WO2014027987A1

WO2014027987A1 - Light emitting apparatus and method of manufacturing and using the same

Info

Publication number: WO2014027987A1
Application number: PCT/US2012/000355
Authority: WO
Inventors: Bradford K. WHITAKER; Kenneth Brownlee
Original assignee: Whitaker Bradford K; Kenneth Brownlee
Priority date: 2012-08-15
Filing date: 2012-08-15
Publication date: 2014-02-20

Abstract

An apparatus includes a load circuit operatively coupled to a controller circuit through a drive circuit. The drive circuit provides a drive signal to the load circuit in response to receiving a digital indication from the controller circuit. The load circuit includes first and second light emitting sub-circuits connected in parallel. The first and second light emitting sub-circuits provide first and second spectrums of light, respectively.

Description

LIGHT EMITTING APPARATUS AND METHOD OF

MANUFACTURING AND USING THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 61/442,329, which was filed on February 14, 201 1 ; to U.S. Provisional Application No. 61/453,364, which was filed on March 16, 2011 ; to U.S. App. No. 13/372,485 filed Feb. 12, 2012; and to PCT/US2012/025030 filed Feb. 14, 2012, the contents of each of which are incorporated by reference herein as though set forth in full below.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002] This invention relates generally to electrical circuits which emit light. Description of the Related Art [0003] It is desirable to provide different spectrums of light for many different applications, such as lighting. Some lighting systems include high power light emitters, such as incandescent and fluorescent lights, and others include lower power light emitters, such as light emitting diodes (LEDs). Examples of lighting systems which include LEDs are disclosed in U.S. Patent Nos. 7,161,31 1, 7,274,160, 7,321 ,203 and 7,572,028, as well as U.S. Patent Application No. 20070103942. While these lighting systems may be useful for their intended purposes, it is highly desirable to have a lighting system which can provide more controllable lighting.

BRIEF SUMMARY OF THE INVENTION

[0004] The present invention is directed to a light emitting apparatus which provides more controllable lighting. The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Like reference characters are used throughout the several views of the drawings.

[0006] FIG. la and lb are block diagrams of embodiments of a light emitting apparatus.

[0007] FIG. lc is a block diagram of one embodiment of a controller circuit of the light emitting apparatus of FIGS, la and lb.

[0008] FIGS. Id and le are perspective and top views, respectively, of one embodiment of the controller circuit of FIG. lc.

[0009] FIGS. If, lg and lh are block diagrams of other embodiments of the light emitting apparatus of FIGS, la and lb.

[0010] Fig. lj is a block diagram depicting how a controller switch can be electrically connected to both a load circuit and drive controller circuit for one or more controller switches. Fig. lj also depicts how a system can have multiple controller switches 114c and 1 14d, for instance.

[0011] FIG. 2a is a graph which includes examples of a positive unipolar analog signal SACI and negative unipolar analog signal SAC2-

[0012] FIG. 2b is a graph of an example of a bipolar analog signal SAC3- [0013] FIG. 2c is a graph which includes examples of a positive unipolar digital signal SDCI and negative unipolar digital signal SDC2-

[0014] FIG. 2d is a graph of an example of a bipolar digital signal SDC3-

[0015] FIG. 2e is a graph of an example of a positive unipolar digital signal SDC4 having a fifty percent (50%) duty cycle.

[0016] FIG. 2f is a graph of an example of a positive unipolar digital signal SDC₅ having a duty cycle that is less than fifty percent (<50%).

[0017] FIG. 2g is a graph of an example of a positive unipolar digital signal SDC6 having a duty cycle that is greater than fifty percent (>50%).

[0018] FIG. 2h is a graph of an example of positive unipolar digital signal SDC6 having a duty cycle that is equal to fifty percent (=50%).

[0019] FIG. 2i is a graph of an example of positive unipolar digital signal SDC7 having a duty cycle that is equal to fifty percent (=50%). [0020] FIG. 3a is a more detailed block diagram of an embodiment of the light emitting apparatus of FIG. lb.

[0021] FIG. 3b is a more detailed block diagram of an embodiment of the light emitting apparatus of FIG. lb.

[0022] FIG. 4a is a circuit diagram of one embodiment of the light emitting apparatus of FIG. 3.

[0023] FIG. 4b is a circuit diagram of one embodiment of the load circuit of FIG. 4a, wherein N=5 and M=l so that diode string DA includes five diodes DAI , D_A2, DA3, DA4 and D_A5 connected in series and diode string DB includes one diode DBI .

[0024] FIG. 4c is a circuit diagram of another embodiment of the load circuit of FIG. 4a, wherein N=5 and M=l so that diode string D_A includes five diodes D_Ai, D_A_, DA3, DA₄ and D_A5 connected in series and diode string DB includes one diode DB_\ .

[0025] FIG. 4d is a circuit diagram of another embodiment of the light emitting apparatus of FIG. 4a.

[0026] FIG. 4e is a circuit diagram of another embodiment of the load circuit of FIG. 4a, wherein N=5 and M=l so that diode string DA includes five diodes DAI , DA2, DA3, DA₄ and DAS connected in series and diode string DB includes one diode DBI -

[0027] FIG. 5a is a circuit diagram of another embodiment of the light emitting apparatus of FIG. 3.

[0028] FIG. 5b is a circuit diagram of one embodiment of the load circuit of FIG. 5a, wherein N=3 and M=2 and L=l so that diode string D_A includes three diodes DAI, DA2 and DA3 connected in series and diode string DB includes two diodes DB\ and DB₂ connected in series and diode string Dc includes one diode Dei.

[0029] FIG. 6a is a circuit diagram of another embodiment of the light emitting apparatus of FIG. 3.

[0030] FIG. 6b is a circuit diagram of one embodiment of the load circuit of FIG. 6a, wherein N=2 and M=3 and L=2 so that diode string D_A includes two diodes D_Ai and DA2 connected in series and diode string DB includes three diodes DBI, DB₂ and DB₃ connected in series and diode string Dc includes two diodes Dei and DQ.

[0031] FIGS. 7, 8a, 8b, and 8c are circuit diagrams of embodiments of a light emitting apparatus. |

[0032] FIG. 9 is a circuit diagram of one embodiment of a load circuit. [0033] FIGS. 10a, 10b, 10c and lOd are graphs of examples of multi-level DC signal SDCIO, SDCU, S_DCI2 and S_DC13, respectively.

[0034] FIG. 1 1a is a graph of an example of a positive unipolar digital signal SDC7 having a fifty percent (50%) duty cycle.

[0035] FIG. 1 lb is a graph of an example of a digital signal Soigitaii shown with positive unipolar digital signal Sr ;7a (in phantom) of FIG. 1 la.

[0036] FIG. 1 lc is a graph of an example of a digital signal Soigitai2 shown with positive unipolar digital signal Soc7b (in phantom) of FIG. 11a.

[0037] FIG. 1 Id is a graph of an example of a digital signal Soigita_B shown with positive unipolar digital signal SDC7_C (in phantom) of FIG. 1 la.

[0038] FIG. 12a is a graph of an example of a bipolar digital signal SDCS-

[0039] FIG. 12b is a graph of an example of a digital signal Soigitaw shown with signal

SDC8₃ (in phantom) and Socsb (in phantom) of FIG. 12a.

[0040] FIG. 12c is a graph of an example of a digital signal Soig_kais shown with signal SDC8_C (in phantom) and Socsd (in phantom) of FIG. 12a.

[0041] FIG. 12d is a graph of an example of a digital signal Soi_gi_taie shown with signal SDC8e (in phantom) and Socsf (in phantom) of FIG. 12a.

[0042] FIG. 13a is a graph of an example of a digital signal Soi_gi_tan shown with signal SoC8a (in phantom) and Socsb (in phantom) of FIG. 12a.

[0043] FIG. 13b is a graph of an example of a digital signal Soigitais shown with signal SDC8_C (in phantom) and Socsd (in phantom) of FIG. 12a.

[0044] FIG. 13c is a graph of an example of a digital signal SDi_gitai shown with signal SDC8e (in phantom) and Socsf (in phantom) of FIG. 12a.

[0045] FIG. 13d is a graph of voltage versus time for one example of output signal SDrive of FIG. lb modulated with a communication signal SCom. FIG. 13d is a graph 169 of an example of a digital signal of FIG. 12a, wherein graph 169 corresponds to voltage verses time. It should be noted that the digital signal can correspond to drive a signal. Digital signal can include a positive one value ("+1"), a negative one value ("-1") and/or a zero value ("0"). A Communication signal (SCom) at a voltage less than a positive one value but more than zero exists to carry communication. When the digital signal is at the Communication signal the drive signal is at a voltage that replaces the Zero value. It should be noted that the drive signal at a positive one value corresponds to a voltage value that is greater than zero volts and a negative one value corresponds to a voltage value that is less than zero volts.

[0046] FIG. 14a and 14b illustrate light switches and faceplates providing color indication of light temperature.

DETAILED DESCRIPTION OF THE INVENTION

[0047] Some embodiments of the present invention are directed towards a lighting system which emulates an incandescent lamp's dimming characteristic of shifting from a colder color to a warmer color when dimmed. The dimming occurs in a controlled manner so that the amount of warm and cold colors provided is controlled, and can be adjusted. In some embodiments, the lighting system includes only two conductors, so that the lighting system can be retrofitted to existing lighting systems.

[0048] In some embodiments, the emulation is achieved by using a pulse wave modulated (PWM) dimming controller and its associated LED lamp. The controller is modified by adding a switching circuit, which provides a variable duty cycle signal and voltage potential reversing PWM signal. Different frequency spectrum (colors) yellow (warm color) LED's and white (cool color) LED's can be included in the LED lamp, and these LED's are connected in reverse polarity so that they react to the PWM signal respective of polarity (direction).

[0049] One example of this application is, as the controller dims, the cooler color LEDs receive a reduced duty cycle signal, and the warmer LEDs receives a PWM signal at a low duty cycle through the reverse polarity. As the lamp dims further, the duty cycle of the cooler color LED's continues to decrease and the warmer LED duty cycle increases, which provides a warmer color from the Lamp. The duty cycles may also be varied and controlled to energize the LED's for other beneficial effects, such as cooler component temperatures, excitation in response to a communication signal, among other effects.

[0050] It should be noted that conventional circuit symbols are included in the drawings to denote circuit elements, such as transistors and resistors. The circuit elements can be discrete circuit elements and integrated circuit elements. Discrete circuit elements are typically mounted onto a circuit board, such as a printed circuit board (PCB), and integrated circuit components are typically formed with an integrated circuit on a piece of semiconductor material.

[0051] FIG. la and lb are block diagrams of embodiments of a light emitting apparatus 100. It should be noted that light emitting apparatus is powered by a power signal, which is not shown for simplicity. The power signal can be provided to light emitting apparatus 100 in many different ways. In some embodiments, the power to light emitting apparatus 100 is provided by an electrical system of a building. For example, most buildings are wired to provide an AC signal at an electrical outlet. Hence, the power signal provided to light emitting apparatus 100 can be from the AC signal of the building. In some situations, the AC signal is a 120 VAC signal and the power signal provided to light emitting apparatus 100 is a corresponding DC signal that is provided by an AC-to-DC converter. However, the AC-to-DC converter is not shown for simplicity. An example of an AC-to-DC converter is disclosed in U.S. Patent Application No. 12/553,893, filed on September 3, 2009, the contents of which are incorporated herein by reference as though fully set forth herein. Examples of AC-to-DC converters are disclosed in U.S. Patent Nos. 5,347,21 1, 6,643,158, 6,650,560, 6,700,808, 6,775,163, 6,791,853 and 6,903,950, the contents of all of which are incorporated by reference as though fully set forth herein. An example of the DC signal will be discussed in more detail below, such as in FIG. 4a, wherein the DC signal is established by establishing voltages VR_en and VR^.

[0052] In these embodiments, light emitting apparatus 100 includes a load circuit 130 operatively coupled to a controller circuit 1 10 through a drive circuit 120. Drive circuit 120 provides a drive signal S Drive to load circuit 130 in response to a digital indication from controller circuit 1 10. The digital indication can be of many different types, such as a digital signal. In FIGS, la and lb, the digital indication corresponds to a digital control signal, denoted as digital control signal Sontroi-

[0053] In some embodiments, the digital indication is adjustable in response to a dimmer signal provided to controller circuit 1 10. The dimmer signal can be provided to controller circuit 1 10 in many different ways, such as by using a dimmer switch. A dimmer switch is used to adjust the intensity of a lamp. An example of a dimmer switch is disclosed in the above-referenced U.S. Patent Application No. 12/553,893.

[0054] The digital indication can be provided to drive circuit 120 from controller circuit 1 10 in many different ways. In FIG. la, the digital indication is provided to drive circuit 120 from controller circuit 1 10 through a conductive line 1 15 so that digital control signal Scontroi corresponds to a first current flow. Further, in FIG. la, the drive signal Sorive is provided to load circuit 130 from drive circuit 120 through a conductive line 125 so that the drive signal Sorive corresponds to a second current flow. It should be noted that a current flow has units of Amperes.

[0055] In FIG. lb, the digital indication is provided to drive circuit 120 from controller circuit 1 10 through a pair of conductive lines 1 17, which includes conductive lines 1 15 and 1 16, so that the digital control signal Scontroi corresponds to a potential difference between conductive lines 1 15 and 1 16. Further, in FIG. lb, the drive signal Sorive is provided to load circuit 130 from drive circuit 120 through a pair of conductive lines 127, which includes conductive lines 125 and 126, so that the drive signal Sorive corresponds to a potential difference between conductive lines 125 and 126. It should be noted that the potential difference is sometimes referred to as a voltage and has units of volts.

[0056] In some embodiments, the digital indication is adjustable in response to a digital signal provided to controller circuit 1 10 via a digital communication signal SCom on the drive signal Sdrive on conductive lines 125 and 126.

[0057] Fig 13d illustrates how Scontroi and SCom can be modulated with a drive signal SDrive. In this embodiment, control assembly 1 10 provides a control signal Scontroi, which is modulated with a communication signal which is modulated with a drive signal Sorive- Fig 13d shows SCom modulated with SControl and SDrive. Communication signal Scom is shown as being a binary signal which alternates between high and low states for simplicity and ease of discussion. However, it should be noted that communication signal Scom typically includes high and low states chosen to correspond to information, such as binary data, and the binary data is chosen to control the operation of an electrical device. In some embodiments, the electrical device includes an electric motor or Solenoid which is operated in response to Drive signal Sorive and/or communication signal Scom- In one example, the electrical device is a ceiling fan which includes a ceiling fan motor. More information regarding ceiling fans is provided in the above-identified related provisional applications. In another example, the electrical device is a vent fan which includes an electrical vent motor.

[0058] In this embodiment, drive signal Sorive and communication signal Scom are both wired signals because the signals are transmitted along one or more wires, such as a conductive line. In this way, the electrical device is operated in response to receiving a wired signal that is modulated with drive signal SDrive- In these embodiments, the electrical device includes a controller that is responsive to wired control signal Scom- (0059] control assembly 1 10 provides a control signal Scontrob which is modulated with a communication signal which is modulated with a drive signal Sorivej as in Fig 13d. Control Circuit 1 10 and Drive Circuit 120 are combined.

[0060] However, in some embodiments, control signal Scontroi is a wireless signal which is flowed wirelessly to the electrical device. In this way, the electrical device is operated in response to receiving a wireless signal that is not modulated with drive signal Sorive- Information regarding an electrical device will be discussed in more detail presently. In these embodiments, the electrical device includes a controller that is responsive to wireless control signal Scontroi through an antenna.

[0061] Fig lj depicts a system 100b that includes a load circuit 130b operatively coupled to drive controller circuit 150 which in this instance includes drive circuit 120 and control circuit 110. In this embodiment, SDrive generated by the drive controller circuit can include the digital signal 169 as depicted in Fig 13d. Controller Switch 114c contains an integrated circuit that can be powered by either SDrive or V3. V3 can stay active when the digital signal SDrive is not present.

[0062] In this embodiment, electrical controller switch 1 14c is connected to conductive lines 127 and 128 and operatively coupled to drive controller circuit 150. The Controller Switch 1 14c can communicate with the drive controller circuit 150 to change the status of load circuit 130b (e.g. light emitting apparatus 1 10b), and change in status may include one or more of color setting, light intensity, circadian time, activation timer, motion sensing, diagnostics, and system activity. Controller switch 114c can generate communication signal Scom and can also modulate that communication signal with drive signal Sdrive and/or control signal Scontroi. The controller switch may be configured to modulate Scom when drive signal voltage is at a value V3 not equal to zero.

[0063] The controller switch 1 14c is connected to conductive lines 127 and 128. The controller switch 1 14c can read digital signal Sdrive and/or Sc₀m from Fig. 13d or otherwise indicate the status of the light emitting apparatus 1 10b on e.g. a face-plate of the controller switch 1 14c. [0064] In this embodiment, two or more electrical controller switches 1 14c and 1 14d are connected to conductive lines 127 and 128 and operatively coupled to drive controller circuit 150. The Controller Switch 1 14c and 1 14d can communicate to the drive controller circuit 150 to change e.g. the status of the light emitting apparatus 1 10b, and command buffering may be used to assist in an order and priority that may be observed by the drive controller circuit 150 to prevent data collisions from the multiple Controller Switches 114c.

[0065] A controller switch may be a light switch as illustrated in Fig. 14a or 14b. The switch 1400 illustrated in Fig. 14a and 14b has a light bar 1410 across the top of a border above switches 1420 and 1430. Light bar 1410 contains LEDs that emit different colors, and as color of light emitted by the LED lamp or e.g. heat of a heater is adjusted by pushing the left or right sides of switch 1420, the switch adjusts color of the light bar to show a warmer color on the bar as the lamp color or heater setpoint becomes warmer and a cooler color on the bar as the lamp color or heater setpoint becomes cooler. The controller switch transmits a communication signal Scorn in response to the user's input to make the color or temperature warmer or cooler. Switch 1420 may also be used to adjust luminance from a lamp by pushing on the upper and lower portions of switch 1420. The switch will send a communication signal Scorn in response to the user's input. Switch 1430 may be used to turn the room lamp or other load on or off.

[0066] A controller switch may be e.g. a hand-operated switch such as those illustrated in Fig. 14a and 14b. A second switch may therefore be a second wall-switch positioned on another wall to allow a lamp to be operated from another portion of a room. A switch may be a motion detector that transmits modulates Sdrive and/or Scontrol with Scorn as motion is detected or as no motion is detected. A switch may be a color sensor that can provide a signal indicative of color of light sensed in a room. A switch may be a light detector that detects presence and/or intensity of light upon the detector. A switch may be a sensor for a remote control as found in home entertainment systems. The signal transmitted by the remote control may be modulated with Sdrive and/or Scontrol by the detection switch, and the detected signal may be repeated and/or rebroadcast by an emitter that constitutes at least part of the load circuit of a system incorporating the detection switch. A switch may be a timer. For instance, a wall switch may have a button or buttons that provide a control signal to the drive controller circuit to operate for 5, 10, 15, 20, or 30 minutes or other time period either pre-programmed or user input. In this case, a drive controller circuit may include a programmable clock.

[0067] Examples of loads that may be driven in a system as described herein include an LED lamp, a heater, a fan, a wireless transmitter, a communications interface for a phone line, and an infrared blaster to retransmit signals from a remote control or otherwise control e.g. home audio and video equipment.

[0068] The color of light in a room or outside may be adjusted according to a Circadian rhythm. In this instance, a system may have at least one of the following components, any two of the following components, or all three of the following components: a light color sensor for the environment to be controlled; a light intensity sensor; and an astronomical clock. Light color is adjusted using a system as described herein and using e.g. a light intensity sensor to immediately or gradually adjust light in response to dimming in the room as well as time of day. Likewise, color of light in the room can be adjusted as e.g. environmental factors change light color (such as a cloud passing before the sun and changing both intensity and color of light) and/or as time progresses through the day. For instance, light color as provided by an LED lamp may be cooler in the morning and may progress to a warmer color through the day. The astronomical clock and controls may be part of digital drive controller circuit 150 of Fig. lj, for instance, or may be a separate controller circuit in communication with drive controller circuit 150.

[0069] In some embodiments, the digital indication is a bipolar digital control signal and, in some embodiments, the drive signal is a bipolar digital drive signal. The drive circuit provides the bipolar digital drive signal in response to receiving the bipolar digital control signal provided by the controller circuit. In some embodiments, the bipolar digital drive signal is adjustable in response to adjusting the bipolar digital control signal. For example, in some embodiments, the duty cycle of the bipolar digital drive signal is adjustable in response to adjusting the duty cycle of the bipolar digital control signal. Further, in some embodiments, the frequency of the bipolar digital drive signal is adjustable in response to adjusting the frequency of the bipolar digital control signal.

[0070] It should be noted that, in general, analog and digital signals are provided by analog and digital circuits, respectively. Information regarding analog signals is provided in more detail below with FIGS. 2a and 2b, and information regarding digital signals is provided in more detail below with FIGS. 2c, 2d, 2e, 2f and 2g. The digital signal can be of many different types, such as a unipolar digital signal and bipolar digital signal. Information regarding unipolar and bipolar digital signals is provided in more detail below with FIGS. 2c and 2d.

[0071] Load circuit 130 can be of many different types. In some embodiments, load circuit 130 includes a motor, such as an electrical motor. In some embodiments, load circuit 130 includes a linear variable differential transformer (LVDT). In some embodiments, load circuit 130 includes power storage device, such as a battery, capacitor and inductor. The inductor can be of many different types, such as a solenoid of a fan.

[0072] In the embodiments of FIGS, la and lb, load circuit 130 includes a light emitting circuit, wherein the light emitting circuit includes a light emitting device, such as a light emitting diode (LED). A light emitting diode includes a pn junction formed by adjacent n-type and p-type semiconductor material layers, wherein the p-type semiconductor material layer corresponds to an anode and the n-type semiconductor material layer corresponds to a cathode. The LED flows light in response to driving a potential difference between the anode and cathode to a voltage value equal to or greater than a diode threshold voltage value. The LED is activated in response to driving the potential difference between the anode and cathode to the voltage value equal to or greater than the diode threshold voltage value. Hence, an activated LED flows light.

[0073] Further, the LED does not flow light in response to driving the potential difference between the anode and cathode to a voltage value less than the diode threshold voltage value. The LED is deactivated in response to driving the potential difference between the anode and cathode to the voltage value less than the diode threshold voltage value. Hence, a deactivated LED does not flow light. The diode threshold voltage value depends on many different properties of the LED, such as the material of the n-type and p- type semiconductor material layers. LEDs are provided by many different manufacturers, such as Cree, Inc. and Nichia Corporation. It should be noted that the diode threshold voltage value can be in many different voltage ranges. In some examples, the diode threshold voltage value is between two volts (2 V) and twenty-five volts (25 V). In one particular example, the diode threshold voltage value is twelve volts (12 V). In another example, the diode threshold voltage value is twenty-four volts (24 V). In another example, the diode threshold voltage value is three volts (3 V). [0074] In some embodiments, load circuit 130 provides first and second frequency spectrums of light in response to receiving a bipolar digital drive signal Sorive from drive circuit 120. The first and second frequency spectrums of light can be adjusted in response to adjusting bipolar digital drive signal Sorive- Bipolar digital drive signal Sorive can be adjusted in many different ways, such as by adjusting digital control signal Scontroi- In this way, light emitting apparatus 100 provides controllable lighting. It should be noted that the frequency spectrum of light corresponds to the color of the light.

[0075] In some embodiments, the amount of light provided by load circuit 130 is adjustable in response to adjusting a duty cycle of drive signal Sorive- The amount of light provided by load circuit 130 increases and decreases in response to decreasing and increasing, respectively, the duty cycle of drive signal Sorive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Scontroi- In this way, light emitting apparatus 100 provides controllable lighting.

[0076] FIG. lc is a block diagram of one embodiment of controller circuit 1 10, which is denoted as controller circuit 110a. In this embodiment, controller circuit 1 10a includes a controller switch 1 14 operatively coupled to a controller chip 111. In particular, controller circuit 1 10a includes conductive lines 1 18 and 1 19 which connect controller switch 1 14 and controller chip 11 1 so that a switch signal Sswitch can flow therebetween. Controller chip 1 1 1 can be of many different types, such as a microcontroller. More information regarding microcontrollers is provided below. Controller chip 1 1 1 moves between activated and deactivated conditions in response to moving controller switch 1 14 between activated and deactivated positions, respectively. In this way, controller switch 114 is operatively coupled to controller chip 11 1. Controller switch 114 can be of many different types, such as an ON/OFF light switch and dimmer switch. An embodiment in which controller switch 1 14 is a dimmer switch will be discussed in more detail with FIGS. Id and le.

[0077] In some embodiments, control switch 1 14 is operatively coupled to the wiring of a building. It should be noted that switch signal Sswitch can be a DC signal, which is provided in response to stepping down the AC power signal provided to the building. More information regarding AC and DC signals, as well as providing a DC signal from the AC signal of a building, can be found in the above-referenced U.S. Patent Application No. 12/553,893. [0078] In operation, controller chip 1 1 1 establishes control signal Scontroi between conductive lines 1 15 and 1 16 in response to adjusting switch signal Sswitch- In this embodiment, switch signal Sswitch is adjusted in response to adjusting controller switch 114. In one mode of operation, control signal Scontroi is driven to a first predetermined value in response to moving controller switch 114 to the activated position. Further, control signal Scontroi is driven to a second predetermined value in response to moving controller switch 1 14 to the deactivated position. In this way, controller chip 1 1 1 establishes control signal Scontroi between conductive lines 115 and 116 in response to adjusting switch signal Sswitch- It should be noted that, in some embodiments, control signal Scontroi is a digital control signal.

[0079] FIGS. Id and le are perspective and top views, respectively, of one embodiment of controller circuit 1 10a of FIG. lc. In this embodiment, controller switch 1 14 is embodied as a dimmer switch 114a, and controller chip 1 1 1 is carried by a circuit board 112. Circuit board 1 12 carries input contact pads 108a and 108b and output contact pads 109a and 109b. Conductive lines 1 18 and 1 19 are connected to corresponding terminals of dimmer switch 1 14a and input contact pads 108a and 108b, respectively. Contact pads 108a and 108b are connected to separate leads of controller chip 11 1. Conductive lines 115 and 1 16 are connected to output contact pads 109a and 109b, respectively, and contact pads 109a and 109b are connected to separate leads of controller chip 1 1 1.

[0080] In operation, controller chip 1 1 1 establishes control signal Scontroi between conductive lines 1 15 and 1 16 in response to adjusting switch signal Sswitch- In this embodiment, switch signal Sswitch is adjusted in response to adjusting dimmer switch 1 14a. In one mode of operation, control signal Scontroi is driven to a first predetermined value in response to moving controller switch 114 to the activated position. Further, control signal Scontroi is driven to a second predetermined value in response to moving controller switch 1 14 to the deactivated position. In this way, controller chip 1 11 establishes control signal Scontroi between conductive lines 1 15 and 1 16 in response to adjusting switch signal Sswitch- It should be noted that the value of switch signal Sswitch varies between voltage values because controller switch 1 14 is embodied as dimmer switch 114a. Hence, control signal Scontroi can have many different values. The value of control signal Scontroi is adjustable in response to adjusting the value of switch signal Sswitch- [0081] It should be noted that, in some embodiments, dimmer switch 1 14a and controller chip 1 1 1 are integrated together, along with an AC-to-DC converter. Examples of such embodiments are discussed in more detail in the above-referenced U.S. Patent Application No. 12/553,893.

[0082] FIG. If is a block diagram of one embodiment of a light emitting apparatus, denoted as light emitting apparatus lOOj. In this embodiment, light emitting apparatus lOOj includes load circuit 130 operatively coupled to controller circuit 1 10 through drive circuit 120, as discussed in more detail above with FIGS, la and lb.

[0083] In this embodiment, light emitting apparatus lOOj includes an electrical device 157 operatively coupled to controller circuit 1 10 through drive circuit 120. Electrical device 157 can be operatively coupled to controller circuit 1 10 through drive circuit 120 in many different ways. In this embodiment, electrical device 157 is connected to conductive lines 125 and 126 so that electrical device 157 receives drive signal Sorive- Electrical device 157 operates in response to receiving drive signal Sorive- [0084] Electrical device 157 can be of many different types of electrical devices, such as an appliance. Electrical device 157 can include many different components, such as an electrical circuit. In some embodiments, the electrical circuit includes a computer chip, such as a transceiver and microcontroller, which is capable of flowing a communication signal. Transceivers and microcontrollers are manufactured by many different companies, such as Analog Devices of Cambridge, Massachusetts and NXP Semiconductors of Eindhoven, The Netherlands. Some types of transceivers manufactured by NXP include the GreenChip series of transceivers, such as the SPR TEA1716, SPF TEA172x, SPF TES1731 and TEA 1792 products. Some types of microcontrollers manufactured by NXP include the LPC2361FBD100 and LPC1857FBD208 products.

[0085] In some embodiments, electrical device 157 is a power storage device 158, as indicated by an indication arrow 154 in FIG. If. Electrical device 157 can be many different types of power storage devices, such as a battery, capacitor and inductor. The battery can be of many different types, such as a rechargeable battery. Examples of rechargeable batteries include lithium-ion batteries and button cell batteries. A button cell battery 158a is indicated by an indication arrow 155 in FIG. If. It should be noted that power storage device 158 is charged in response to receiving drive signal Sorive during normal operation. It should also be noted that power storage device 158 can provide signal SDrive to load circuit 130, such as when the DC signal provided to drive circuit 120 is driven to zero volts. The DC signal provided to drive circuit 120 is driven to zero volts such as in a power outage. In this way, power storage device 158 can provide back-up power to load circuit 130.

[0086] As mentioned above, electrical device 157 can include an inductor. The inductor can be of many different types, such as a solenoid of a fan. In the inductor embodiments, the fan can be used to remove heat from load circuit 130. It should be noted that the fan operates in response to receiving drive signal Sorive-

[0087] Drive circuit 120 provides drive signal Sorive to load circuit 130 in response to a digital indication from controller circuit 1 10. The digital indication can be of many different types, such as a digital signal. In FIGS, la and lb, the digital indication corresponds to a digital control signal, denoted as digital control signal Scontroi- [0088] In some embodiments, the digital indication is adjustable in response to a dimmer signal provided to controller circuit 1 10. The dimmer signal can be provided to controller circuit 1 10 in many different ways, such as by using a dimmer switch. A dimmer switch is used to dim a light. An example of a dimmer switch is disclosed in U.S. Patent Application No. 12/553,893, filed on September 3, 2009, the contents of which are incorporated herein by reference as though fully set forth herein.

[0089] The digital indication can be provided to drive circuit 120 from controller circuit 1 10 in many different ways. In FIG. la, the digital indication is provided to drive circuit 120 from controller circuit 1 10 through a conductive line 1 15 so that digital control signal Scontroi corresponds to a first current flow. Further, in FIG. la, the drive signal Sorive is provided to load circuit 130 from drive circuit 120 through a conductive line 125 so that the drive signal Sorive corresponds to a second current flow. It should be noted that a current flow has units of Amperes.

[0090] In FIG. lb, the digital indication is provided to drive circuit 120 from controller circuit 1 10 through a pair of conductive lines 1 17, which includes conductive lines 1 15 and 1 16, so that the digital control signal Scontroi corresponds to a potential difference between conductive lines 1 15 and 116. Further, in FIG. lb, the drive signal Sorive is provided to load circuit 130 from drive circuit 120 through a pair of conductive lines 127, which includes conductive lines 125 and 126, so that the drive signal Sorive corresponds to a potential difference between conductive lines 125 and 126. It should be noted that the potential difference is sometimes referred to as a voltage and has units of volts.

[0091] In some embodiments, the digital indication is a bipolar digital control signal and, in some embodiments, the drive signal is a bipolar digital drive signal. The drive circuit provides the bipolar digital drive signal in response to receiving the bipolar digital control signal provided by the controller circuit. In some embodiments, the bipolar digital drive signal is adjustable in response to adjusting the bipolar digital control signal. For example, in some embodiments, the duty cycle of the bipolar digital drive signal is adjustable in response to adjusting the duty cycle of the bipolar digital control signal. Further, in some embodiments, the frequency of the bipolar digital drive signal is adjustable in response to adjusting the frequency of the bipolar digital control signal.

[0092] It should be noted that, in general, analog and digital signals are provided by analog and digital circuits, respectively. Information regarding analog signals is provided in more detail below with FIGS. 2a and 2b, and information regarding digital signals is provided in more detail below with FIGS. 2c, 2d, 2e, 2f, 2g and 2h. The digital signal can be of many different types, such as a unipolar digital signal and bipolar digital signal. Information regarding unipolar and bipolar digital signals is provided in more detail below with FIGS. 2c and 2d.

[0093] Load circuit 130 can be of many different types. In some embodiments, load circuit 130 includes a motor, such as an electrical motor. In some embodiments, load circuit 130 includes a linear variable differential transformer (LVDT). In some embodiments, load circuit 130 includes power storage device, such as a solenoid.

[0094] In the embodiments of FIGS, la and lb, load circuit 130 includes a light emitting circuit, wherein the light emitting circuit includes a light emitting device, such as a light emitting diode (LED). A light emitting diode includes a pn junction formed by adjacent n-type and p-type semiconductor material layers, wherein the p-type semiconductor material layer corresponds to an anode and the n-type semiconductor material layer corresponds to a cathode. The LED flows light in response to driving a potential difference between the anode and cathode to a voltage value equal to or greater than a diode threshold voltage value. The LED is activated in response to driving the potential difference between the anode and cathode to the voltage value equal to or greater than the diode threshold voltage value. Hence, an activated LED flows light. [0095] Further, the LED does not flow light in response to driving the potential difference between the anode and cathode to a voltage value less than the diode threshold voltage value. The LED is deactivated in response to driving the potential difference between the anode and cathode to the voltage value less than the diode threshold voltage value. Hence, a deactivated LED does not flow light. The diode threshold voltage value depends on many different properties of the LED, such as the material of the n-type and p- type semiconductor material layers. LEDs are provided by many different manufacturers, such as Cree, Inc. and Nichia Corporation. It should be noted that the diode threshold voltage value can be in many different voltage ranges. In some examples, the diode threshold voltage value is between two volts (2 V) and twenty-five volts (25 V). In one particular example, the diode threshold voltage value is twelve volts (12 V). In another example, the diode threshold voltage value is twenty-four volts (24 V).

[0096] In some embodiments, load circuit 130 provides first and second frequency spectrums of light in response to receiving a bipolar digital drive signal Sorive from drive circuit 120. The first and second frequency spectrums of light can be adjusted in response to adjusting bipolar digital drive signal Sorive- Bipolar digital drive signal Sorive can be adjusted in many different ways, such as by adjusting digital control signal Scontroi- In this way, light emitting apparatus 100 provides controllable lighting. It should be noted that the frequency spectrum of light corresponds to the color of the light. It should also be noted that, in some embodiments, load circuit 130 can provide two or more frequency spectrums of light in response to receiving a bipolar digital drive signal Sorive from drive circuit 120.

[0097] In some embodiments, the amount of light provided by load circuit 130 is adjustable in response to adjusting a duty cycle of drive signal Sorive- The amount of light provided by load circuit 130 increases and decreases in response to decreasing and increasing, respectively, the duty cycle of drive signal Sorive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Scontroi- hi this way, light emitting apparatus 100 provides controllable lighting.

[0098] FIG. lg is a block diagram of one embodiment of a light emitting apparatus, denoted as light emitting apparatus 100k. In this embodiment, light emitting apparatus 100k includes a load circuit 130a operatively coupled to controller circuit 1 10 through a drive circuit 120a. Drive circuit 120a provides a drive signal Sorivei to load circuit 130a in response to a first digital indication from controller circuit 110. The first digital indication can be of many different types, such as a digital signal. In FIG. lg, the first digital indication corresponds to a digital control signal, denoted as digital control signal Scontroii - [0099] In FIG. lg, the first digital indication is provided to drive circuit 120a from controller circuit 110 through a pair of conductive lines 1 17a, which includes conductive lines 1 15a and 1 16a, so that the digital control signal Scontroii corresponds to a potential difference between conductive lines 1 15a and 1 16a. Further, in FIG. lg, the drive signal SDrivei is provided to load circuit 130a from drive circuit 120a through a pair of conductive lines 127a, which includes conductive lines 125a and 126a, so that the drive signal Sorivei corresponds to a potential difference between conductive lines 125a and 126a.

[00100] In FIG. lg, the operation of drive circuit 120a is adjustable in response to receiving an indication from controller circuit 110. The indication can be of many different types. In this embodiment, the indication corresponds to a control signal Sc₀ntroi3, which flows between controller circuit 110 and drive circuit 120a through a conductive line 128. In some embodiments, control signal ScontroB is a wireless signal. Drive circuit 120a is repeatably moveable between active and deactive conditions in response to adjusting control signal Scontroo- In the active condition, drive circuit 120a provides drive signal Sorivei and, in the deactive condition, drive circuit 120a does not provide drive signal Sorivei - [00101] In this embodiment, light emitting apparatus 100k includes a load circuit 130b operatively coupled to controller circuit 1 10 through a drive circuit 120b. Drive circuit 120b provides a drive signal SD_rive2 to load circuit 130b in response to a second digital indication from controller circuit 1 10. The second digital indication can be of many different types, such as a digital signal. In FIG. lg, the second digital indication corresponds to a digital control signal, denoted as digital control signal Sc₀ntroi2- [00102] In FIG. lg, the second digital indication is provided to drive circuit 120b from controller circuit 1 10 through a pair of conductive lines 1 17b, which includes conductive lines 1 15b and 1 16b, so that the digital control signal Scontroi2 corresponds to a potential difference between conductive lines 1 15b and 1 16b. Further, in FIG. lg, the drive signal SDrive2 is provided to load circuit 130b from drive circuit 120b through a pair of conductive lines 127b, which includes conductive lines 125b and 126b, so that the drive signal Sorive2 corresponds to a potential difference between conductive lines 125b and 126b. [00103] In FIG. lg, the operation of drive circuit 120b is adjustable in response to receiving an indication from controller circuit 110. The indication can be of many different types. In this embodiment, the indication corresponds to a control signal Scontrow. which flows between controller circuit 1 10 and drive circuit 120b through a conductive line 129. In some embodiments, control signal Scontrow is a wireless signal. Drive circuit 120b is repeatably moveable between active and deactive conditions in response to adjusting control signal Scontrow- In the active condition, drive circuit 120b provides drive signal Sorive2 and, in the deactive condition, drive circuit 120b does not provide drive signal SDrive2- [00104] FIG. lh is a block diagram of one embodiment of a light emitting apparatus, denoted as light emitting apparatus 1001. In this embodiment, light emitting apparatus 1001 includes load circuit 130a operatively coupled to controller circuit 1 10 through drive circuit 120a. Drive circuit 120a provides drive signal S Drive ι to load circuit 130a in response to the first digital indication from controller circuit 1 10. The first digital indication can be of many different types, such as a digital signal. In FIG. lg, the first digital indication corresponds to digital control signal Scontroii -

[00105] In FIG. lg, the first digital indication is provided to drive circuit 120a from controller circuit 1 10 through the pair of conductive lines 117a, which includes conductive lines 1 15a and 1 16a, so that the digital control signal Scontroii corresponds to a potential difference between conductive lines 115a and 1 16a. Further, in FIG. lg, the drive signal Sorivei is provided to load circuit 130a from drive circuit 120a through the pair of conductive lines 127a, which includes conductive lines 125a and 126a, so that the drive signal Sorivei corresponds to a potential difference between conductive lines 125a and 126a.

[00106] In this embodiment, light emitting apparatus 1001 includes electrical device 157, which is operatively coupled to drive circuit 120a. Electrical device 157 can be operatively coupled to drive circuit 120a in many different ways. In this embodiment, electrical device 157 is connected to conductive lines 125a and 126a so that electrical device 157 receives drive signal Sorivei - Electrical device 157 operates in response to receiving drive signal

Sorivei -

[00107] In this embodiment, light emitting apparatus 1001 includes load circuit 130b operatively coupled to controller circuit 1 10 through drive circuit 120b. Drive circuit 120b provides drive signal Sr ive2 to load circuit 130b in response to the second digital indication from controller circuit 1 10. The second digital indication can be of many different types, such as a digital signal. In FIG. lg, the second digital indication corresponds to digital control signal Scontroo-

[00108] In FIG. lg, the second digital indication is provided to drive circuit 120b from controller circuit 1 10 through the pair of conductive lines 1 17b, which includes conductive lines 1 15b and 1 16b, so that the digital control signal Scontroi2 corresponds to a potential difference between conductive lines 1 15b and 1 16b. Further, in FIG. lg, the drive signal SDrive2 is provided to load circuit 130b from drive circuit 120b through the pair of conductive lines 127b, which includes conductive lines 125b and 126b, so that the drive signal Sorive2 corresponds to a potential difference between conductive lines 125b and 126b.

[00109] In this embodiment, light emitting apparatus 1001 includes power storage device 158, which is operatively coupled to drive circuit 120b. Power storage device 158 can be operatively coupled to drive circuit 120b in many different ways. In this embodiment, power storage device 158 is connected to conductive lines 125b and 126b so that power storage device 158 receives drive signal Sorive2- Power storage device 158 operates in response to receiving drive signal Sorive2- As mentioned above, power storage device 158 can be of many different types, such as a rechargeable battery. Button cell battery 158a is indicated by indication arrow 155 in FIG. lh. It should be noted that power storage device 158 can provide signal SDrive2 to load circuit 130a, such as when the DC signal provided to drive circuit 120b is driven to zero volts. The DC signal provided to drive circuit 120b is driven to zero volts such as in a power outage. In this way, power storage device 158 can provide back-up power to load circuit 130b.

[00110] FIG. 2a is a graph 140 which includes examples of a positive unipolar analog signal SACI and negative unipolar analog signal SAC2, wherein graph 140 corresponds to voltage verses time. In this example, positive unipolar analog signal SACI is a periodic sinusoidal signal having a period Ti, wherein a periodic signal repeats itself after a time corresponding to the period. The period corresponds to a time value and is inversely related to the frequency / of the signal by the relation Ύ-lff, so that the period T increases and decreases as frequency decreases and increases, respectively.

[00111] Positive unipolar analog signal SACI has magnitude VMag which varies about a reference voltage VREF, wherein VREF has a positive voltage value. Signal S_Aci is a positive unipolar signal because it has positive voltage values for period Ti . Signal S_Aci is a positive unipolar signal because it does not have negative voltage values for period Ti. Signal SACI is not a bipolar signal because signal SACI has positive voltage values for period T_\. Signal SACI is not a bipolar signal because signal SACI does not have positive and negative voltage values for period T .

[00112] In this example, negative unipolar analog signal SAC2 is a periodic sinusoidal signal having period Tj. Negative unipolar analog signal SAC2 has magnitude V^ag which varies about a reference voltage -VREF, wherein -VREF has a negative voltage value. Signal SAC2 is a negative unipolar signal because it has negative voltage values for period T_\. Signal SAC2 is a negative unipolar signal because it does not have positive voltage values for period Ύ\. Signal SAC2 is not a bipolar signal because signal SAC has negative voltage values for period Tj. Signal SAC2 is not a bipolar signal because signal S_AC2 does not have positive and negative voltage values for period TV

[00113] FIG. 2b is a graph 141 of an example of a bipolar analog signal SAC3, wherein graph 141 corresponds to voltage verses time. In this example, bipolar analog signal SAC3 is a periodic sinusoidal signal having period TV Bipolar analog signal SAC3 has magnitude VMa which varies about a zero voltage value. Signal SAC3 is a bipolar signal because it has positive and negative voltage values for period T\. Signal SAC3 is not a unipolar signal because signal SAC3 has positive and negative voltage values for period Tj.

[00114] FIG. 2c is a graph 142 which includes examples of a positive unipolar digital signal SDCI and negative unipolar digital signal SDC2, wherein graph 142 corresponds to voltage verses time. In this example, positive unipolar digital signal SDCI is a periodic non- sinusoidal signal having period T_\. Positive unipolar digital signal SDCI has magnitude VMag which varies about positive reference voltage VREF, wherein VREF has a positive voltage value. Signal SDCI is a positive unipolar signal because it has positive voltage values for period T_\. Signal SDCI is a positive unipolar signal because it does not have negative voltage values for period Tj. It should be noted that a voltage value of zero volts corresponds to a positive voltage value. Signal SDCI is not a bipolar signal because signal SDCI has positive voltage values for period T\. Signal SDCI is not a bipolar signal because signal SDCI does not have negative voltage values for period ΊΥ Signal SDCI is not a bipolar signal because signal SDCI does not have positive and negative voltage values for period

[00115] For period Ti, digital signal SDCI includes an active edge between rising and falling edges, as well as a deactive edge between rising and falling edges. The active and deactive edges have constant positive voltage values, wherein the voltage value of the active edge has a larger magnitude than the voltage value of the deactive edge. In a digital circuit, the active edge corresponds to a one (" 1 ") because it has a voltage value greater than positive reference voltage VREF and the deactive edge corresponds to a zero ("0") because it has a voltage value less than positive reference voltage VREF- [00116] In this example, negative unipolar digital signal SDC2 is a periodic non-sinusoidal signal having period Tj. Negative unipolar digital signal SDC2 has magnitude VMag which varies about negative reference voltage -VREF, wherein -VREF has a negative voltage value. Signal SDC2 is a negative unipolar signal because it has negative voltage values for period T) . Signal SDC2 is a negative unipolar signal because it does not have positive voltage values for period Tj. It should be noted that a voltage value of zero volts does not correspond to a negative voltage value. Signal SDC₂ is not a bipolar signal because signal SDCI has negative voltage values for period ΊΥ Signal SDC2 is not a bipolar signal because signal SDC2 does not have positive voltage values for period T_\. Signal SDC2 is not a bipolar signal because signal SDC2 does not have positive and negative voltage values for period Tj. For period T) , digital signal SDC2 includes an active edge between rising and falling edges, as well as a deactive edge between rising and falling edges. The active and deactive edges have constant negative voltage values, wherein the voltage value of the active edge has a larger magnitude than the voltage value of the deactive edge. In a digital circuit, the active edge corresponds to a one ("1 ") because it has a voltage value greater than negative reference voltage -VREF and the deactive edge corresponds to a zero ("0") because it has a voltage value less than negative reference voltage -VREF-

[00117] FIG. 2d is a graph 143 of an example of a bipolar digital signal SDC₃, wherein graph 143 corresponds to voltage verses time. In this example, bipolar digital signal SDC3 is a periodic sinusoidal signal having period T\. Bipolar digital signal SDC3 has magnitude V ag which varies about a zero voltage value. Signal SDC₃ is a bipolar signal because it has positive and negative voltage values for period Ύ_\. Signal SDC3 is not a unipolar signal because signal SDC3 has positive and negative voltage values for period

The positive and negative voltage values of bipolar digital signal SDC3 have magnitudes of V agi and V ag2, respectively, wherein the sum of magnitudes V_Magi and VMag2 is equal to magnitude V ag- In some embodiments, the values of magnitudes V agi and V ag2 are the same so that the value of magnitude VMagi is equal to the value of magnitude V_Mag2- i other embodiments, the values of magnitudes VMagi and VM_ag2 are not the same. For example, in some embodiments, the value of magnitude V_Magi is greater than the value of magnitude V ag2 so that the value of magnitude V_Mag2 is less than the value of magnitude VMagi - In other embodiments, the value of magnitude V_Mag2 is greater than the value of magnitude VMagi so that the value of magnitude V agi is less than the value of magnitude V iagi- [00118] It should be noted that bipolar digital signal SDC3 includes active, deactive, rising and falling edges, which are discussed in more detail above. The active edges of bipolar digital signal SDC3 have values greater than the zero voltage value, and the deactive edges of the bipolar digital signal SDC3 have values less than the zero voltage value.

[00119] FIG. 2e is a graph 144 of an example of a positive unipolar digital signal SDC4 having a fifty percent (50%) duty cycle, wherein graph 144 corresponds to voltage verses time. More information regarding duty cycles can be found in U.S. Patent Nos. 7,042,379 and 7,773,016. In this example, positive unipolar digital signal SDC4 is a periodic non- sinusoidal signal having period T₂. Signal SDC is a positive unipolar signal because it has positive voltage values for period T₂. It should be noted that the deactive edge of signal SDC4 has a zero voltage value, which is a positive voltage value, as mentioned above. Signal SDC4 is not a bipolar signal because signal SDC4 has positive voltage values for period T₂.

[00120] Positive unipolar digital signal SDC4 has a fifty percent (50%) duty cycle because the length of time of its active edge is the same as the length of time of its deactive edge. In this particular example, the active edge of signal SDC4 extends between times t_\ and t₂, wherein time t₂ is greater than time tj. Further, the deactive edge of signal SDC extends between times t₂ and t₃, wherein time t₃ is greater than time t₂. Positive unipolar digital signal SQC4 has a fifty percent (50%) duty cycle because the time difference between times t₂ and ti is the same as the time difference between times t₃ and t₂. In this way, positive unipolar digital signal SDC4 has a fifty percent (50%) duty cycle because the length of time of its active edge is the same as the length of time of its deactive edge. It should be noted that, in this example, time ti corresponds to the time of the rising edge of signal SDC4, time t₂ corresponds to the time of the falling edge of signal SQC4 and the difference between times ti and t₃ corresponds to period T₂.

[00121] FIG. 2f is a graph 145 of an example of a positive unipolar digital signal SDCS having a duty cycle that is less than fifty percent (<50%), wherein graph 145 corresponds to voltage verses time. In this example, positive unipolar digital signal SDCS is a periodic non- sinusoidal signal having period T₂. Signal SDCS is a positive unipolar signal because it has positive voltage values for period T₂. It should be noted that the deactive edge of signal SDC5 has a zero voltage value, which is a positive voltage value, as mentioned above. Signal SDC5 is not a bipolar signal because signal SDCS has positive voltage values for period T₂.

[00122] Positive unipolar digital signal SDCS has a duty cycle that is less than fifty percent (<50%) because the length of time of its active edge is less than the length of time of its deactive edge. In this particular example, the active edge of signal SDCS extends between times and t₂, wherein time t₂ is greater than time t_\. Further, the deactive edge of signal SDCS extends between times t₂ and t₃, wherein time t₃ is greater than time t₂. Positive unipolar digital signal SDCS has a duty cycle that is less than fifty percent (<50%) because the time difference between times t₂ and ti is less than the time difference between times t₃ and t₂. In this way, positive unipolar digital signal SDCS has a duty cycle that is less than fifty percent (<50%) because the length of time of its active edge is less than the length of time of its deactive edge. It should be noted that, in this example, time tj corresponds to the time of the rising edge of signal SDCS_> time t₂ corresponds to the time of the falling edge of signal SDCS and the difference between times ti and t3 corresponds to period T₂.

[00123] FIG. 2g is a graph 146 of an example of a positive unipolar digital signal SDC₆ having a duty cycle that is greater than fifty percent (>50%), wherein graph 146 corresponds to voltage verses time. In this example, positive unipolar digital signal SDC6 is a periodic non-sinusoidal signal having period T₂. Signal SDC6 is a positive unipolar signal because it has positive voltage values for period T₂. It should be noted that the deactive edge of signal SDC6 has a zero voltage value, which is a positive voltage value, as mentioned above. Signal SDC₆ is not a bipolar signal because signal SDC6 has positive voltage values for period T₂.

[00124] Positive unipolar digital signal SDC6 has a duty cycle that is greater than fifty percent (>50%) because the length of time of its active edge is greater than the length of time of its deactive edge. In this particular example, the active edge of signal SDC6 extends between times ti and t₂, wherein time t₂ is greater than time t_\. Further, the deactive edge of signal SDC6 extends between times t₂ and t₃, wherein time t₃ is greater than time t₂. Positive unipolar digital signal SDC6 has a duty cycle that is greater than fifty percent (>50%) because the time difference between times t₂ and ti is greater than the time difference between times t₃ and t₂. In this way, positive unipolar digital signal SDC6 has a duty cycle that is greater than fifty percent (>50%) because the length of time of its active edge is greater than the length of time of its deactive edge. It should be noted that, in this example, time corresponds to the time of the rising edge of signal SDC6_> time t₂ corresponds to the time of the falling edge of signal SDC₆ and the difference between times ti and t₃ corresponds to period T₂.

[00125] FIG. 2h is a graph 146a of an example of positive unipolar digital signal SDC6 having a duty cycle that is equal to fifty percent (=50%), wherein graph 146a corresponds to voltage verses time. In this example, positive unipolar digital signal SDC6 is a periodic non- sinusoidal signal having period T₂. Signal SDC₆ is a positive unipolar signal because it has positive voltage values for period T₂. It should be noted that the deactive edge of signal SDC6 has a zero voltage value, which is a positive voltage value, as mentioned above. Signal SDC6 is not a bipolar signal because signal SDC6 has positive voltage values for period T₂.

[00126] Positive unipolar digital signal SDC6 has a duty cycle that is equal to fifty percent (=50%) because the length of time of its active edge is the same as the length of time of its deactive edge. In this particular example, the active edge of signal SDC6 extends between times t] and t₂, wherein time t₂ is greater than time tj. Further, the deactive edge of signal SDC6 extends between times t₂ and t₃, wherein time t₃ is greater than time t₂. Positive unipolar digital signal SDC₆ has a duty cycle that is equal to fifty percent (=50%) because the time difference between times t₂ and ti is the same as the time difference between times t₃ and t₂. In this way, positive unipolar digital signal SDC₆ has a duty cycle that is equal to fifty percent (=50%) because the length of time of its active edge is equal to the length of time of its deactive edge. It should be noted that, in this example, time ti corresponds to the time of the rising edge of signal SDC6_> time t₂ corresponds to the time of the falling edge of signal SDC6 and the difference between times tj and t₃ corresponds to period T₂.

[00127] FIG. 2i is a graph 146b of an example of positive unipolar digital signal SDC₇ having a duty cycle that is equal to fifty percent (=50%), wherein graph 146b corresponds to voltage verses time. In this example, the pulse between times ti and t₃ corresponds to a number of pulses within period T₂, wherein the number of pulses correspond to a number of bits of information. In this particular example, the number of bits between times ti and t₅ is four and the number of bits between times t₅ and t₉ is three. The number of bits is adjustable in response to adjusting the control signal provided by a controller circuit, such as controller circuit 1 10, which is discussed above. Signal SDC7 can be used to drive the LED's of a light emitting sub-circuit so that information can be flowed in the form of light pulses.

[00128] FIG. 2j is a graph 146c of an example of positive bipolar digital signal SDC9 having a duty cycle that is equal to fifty percent (=50%), wherein graph 146b corresponds to voltage verses time. In this example, the pulse between times tj and t₇ corresponds to a number of pulses within period T₂, wherein the number of pulses correspond to a number of bits of information. It should be noted that some of the pulses correspond to positive pulses and other pulses correspond to negative pulses. Hence, in a circuit in which LED's are connected together in reverse parallel, the positive pulse can be used to drive one LED and the negative pulse can be used to drive the other LED. In this particular example, the number of positive pulses is equal to six (6) and the number of negative pulses is equal to five (5). The number of positive and negative pulses is adjustable in response to adjusting the control signal provided by a controller circuit, such as controller circuit 110, which is discussed above. Signal SDC can be used to drive the LED's of first and second light emitting sub-circuits, which are connected in reverse parallel, so that information can be flowed in the form of light pulses.

[00129] FIG. 3a is a more detailed block diagram of an embodiment of light emitting apparatus 100 of FIG. lb, denoted as light emitting apparatus 100a. In this embodiment, light emitting apparatus 100a includes a load circuit 130a operatively coupled to controller circuit 110 through drive circuit 120. In this embodiment, drive circuit 120 includes a drive input circuit 121 operatively coupled to controller circuit 1 10 and a switching circuit 122 operatively coupled to drive input circuit 121 and load circuit 130a.

[00130] In operation, drive circuit 120 provides drive signal Sorive to load circuit 130a in response to a digital indication from controller circuit 110, wherein the digital indication corresponds to a digital control signal Scontroi- Drive circuit 120 can provide drive signal Sorive to load circuit 130a in many different ways. In this embodiment, drive input circuit 121 provides a drive input signal

to switching circuit 122 in response to receiving digital control signal Scontroi, and switching circuit 122 provides drive signal S Drive to load circuit 130a in response to receiving drive input signal Sin_put from drive input circuit 121.

[00131] In this embodiment, load circuit 130a includes light emitting sub-circuits 131 and 132 connected in parallel so they have opposite polarities. Light emitting sub-circuits 131 and 132 are connected in parallel so they have opposite polarities because an anode of light emitting sub-circuit 131 is connected to a cathode of light emitting sub-circuit 132. Further, light emitting sub-circuits 131 and 132 are connected in parallel so they have opposite polarities because a cathode of light emitting sub-circuit 131 is connected to an anode of light emitting sub-circuit 132. In this embodiment, light emitting sub-circuits 131 and 132 have opposite polarities so that, during a first operating condition, light emitting sub-circuit

131 emits light and light emitting sub-circuit 132 does not emit light and, during a second operating condition, light emitting sub-circuit 131 does not emit light and light emitting sub-circuit 132 does emit light. Light emitting sub-circuits 131 and 132 are repeatably moveable between the first and second conditions in response to load circuit 130a receiving drive signal Sorive- Light emitting sub-circuits 131 and 132 can include many different types of light emitting devices, such as those discussed in more detail above.

[00132] It should be noted that, in this embodiment, signals Scontroi, Si_nput and Sorive are digital signals. In some embodiments, signals Scontroi, S_lnput and Sorive are bipolar digital signals and, in other embodiments, signals Scontroi, S_{ln u}t and Sorive are unipolar digital signals. In some embodiments, signals Scontroi, Si_nput and Sorive are positive unipolar digital signals and, in other embodiments, signals Scontroi, in_put and Sorive are negative unipolar digital signals.

[00133] In this embodiment, light emitting sub-circuits 131 and 132 provide first and second frequency spectrums of light in response to receiving a bipolar digital drive signal Sorive from switching circuit 122. The first and second frequency spectrums of light can be adjusted in response to adjusting bipolar digital drive signal Sorive- Bipolar digital drive signal Sorive can be adjusted in many different ways, such as by adjusting digital control signal Scontroi- In this way, light emitting apparatus 100a provides controllable lighting.

[00134] In some embodiments, the amount of light provided by light emitting sub-circuit 131 is adjustable in response to adjusting a duty cycle of drive signal Sorive- The amount of light provided by light emitting sub-circuit 131 increases and decreases in response to increasing and decreasing, respectively, the duty cycle of drive signal Sorive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Scontroi- In this way, light emitting sub-circuit 131 provides controllable lighting.

[00135] In some embodiments, the amount of light provided by light emitting sub-circuit

132 is adjustable in response to adjusting a duty cycle of drive signal Sorive- The amount of light provided by light emitting sub-circuit 132 increases and decreases in response to increasing and decreasing, respectively, the duty cycle of drive signal SDrive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Scontroi- In this way, light emitting apparatus 100a provides controllable lighting.

[00136] Light emitting sub-circuits 131 and 132 can be of many different types. In the embodiments indicated by indication arrow 152 of FIG. 3a, light emitting sub-circuits 131 and 132 are lamps 123 and 124, respectively. In this embodiment, lamps 123 and 124 each include a light emitting diode. More information regarding light emitting diodes is provided in the Background, as well as with some of the other drawings included herein.

[00137] Light emitting sub-circuits 131 and 132 can provide many different frequency spectrums of light. The frequency spectrum of light can be in the visible spectrum and the non-visible spectrum. The visible spectrum includes frequency spectrums detectable by the normal human eye and the non-visible spectrum includes frequency spectrums that are not detectable by the normal human eye. In general, the visible frequency spectrum includes light having a color of between red and violet, such as red, orange, green, blue, indigo and violet. The non-visible frequency spectrum includes light having a color of infrared and ultraviolet.

[00138] FIG. 3b is a more detailed block diagram of an embodiment of light emitting apparatus 100 of FIG. lb, denoted as light emitting apparatus lOOi. In this embodiment, light emitting apparatus lOOi includes load circuit 130a operatively coupled to controller circuit 1 10 through drive circuit 120. In this embodiment, drive circuit 120 includes drive input circuit 121 operatively coupled to controller circuit 110 and switching circuit 122 operatively coupled to drive input circuit 121 and load circuit 130a.

[00139] In operation, drive circuit 120 provides drive signal Sorive to load circuit 130a in response to a digital indication from controller circuit 110, wherein the digital indication corresponds to a digital control signal Scontroi- Drive circuit 120 can provide drive signal Sprive to load circuit 130a in many different ways. In this embodiment, drive input circuit 121 provides drive input signal Si_nput to switching circuit 122 in response to receiving digital control signal Scontroi, and switching circuit 122 provides drive signal Sorive to load circuit 130a in response to receiving drive input signal Si_{n u}t from drive input circuit 121. [00140] In this embodiment, load circuit 130a includes light emitting sub-circuits 131 and 132 connected in parallel so they have opposite polarities, as well as a communication sub- circuit 134.

[00141] In this embodiment, communication sub-circuit 134 is in communication with controller circuit 1 10 through a conductive line 106 so that a communication signal Scomm can flow therebetween. In this way, communication signal Scomm is a wired signal. In some embodiments, controller circuit 1 10 and communication sub-circuit 134 each include a transceiver (not shown) so that communication signal Scomm is a wireless signal.

[00142] Light emitting sub-circuits 131 and 132 are connected in parallel so they have opposite polarities because an anode of light emitting sub-circuit 131 is connected to a cathode of light emitting sub-circuit 132. Further, light emitting sub-circuits 131 and 132 are connected in parallel so they have opposite polarities because a cathode of light emitting sub-circuit 131 is connected to an anode of light emitting sub-circuit 132. In this embodiment, light emitting sub-circuits 131 and 132 have opposite polarities so that, during a first operating condition, light emitting sub-circuit 131 emits light and light emitting sub- circuit 132 does not emit light and, during a second operating condition, light emitting sub- circuit 131 does not emit light and light emitting sub-circuit 132 does emit light. Light emitting sub-circuits 131 and 132 are repeatably moveable between the first and second conditions in response to load circuit 130a receiving drive signal Sorive- Light emitting sub- circuits 131 and 132 can include many different types of light emitting devices, such as those discussed in more detail above.

[00143] It should be noted that, in this embodiment, signals Scontroi,

and Sorive are digital signals. In some embodiments, signals Scontroi, Sin_put and S_Drj_ve are bipolar digital signals and, in other embodiments, signals Scontroi, Sin_put and Sorive are unipolar digital signals. In some embodiments, signals Scontroi, Si_nput and Sorive are positive unipolar digital signals and, in other embodiments, signals Scontroi, Si_nput and Sorive are negative unipolar digital signals.

[00144] In this embodiment, light emitting sub-circuits 131 and 132 provide first and second frequency spectrums of light in response to receiving a bipolar digital drive signal Sorive from switching circuit 122. The first and second frequency spectrums of light can be adjusted in response to adjusting bipolar digital drive signal Sorive- Bipolar digital drive signal Sorive can be adjusted in many different ways, such as by adjusting digital control signal Scontroi- In this way, light emitting apparatus lOOi provides controllable lighting.

[00145] In some embodiments, the amount of light provided by light emitting sub-circuit

131 is adjustable in response to adjusting a duty cycle of drive signal Sorive- The amount of light provided by light emitting sub-circuit 131 increases and decreases in response to increasing and decreasing, respectively, the duty cycle of drive signal Sorive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Scontroi- In this way, light emitting sub-circuit 131 provides controllable lighting.

[00146] In some embodiments, the amount of light provided by light emitting sub-circuit

132 is adjustable in response to adjusting a duty cycle of drive signal Sorive- The amount of light provided by light emitting sub-circuit 132 increases and decreases in response to increasing and decreasing, respectively, the duty cycle of drive signal Sorive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Scontroi- In this way, light emitting apparatus lOOi provides controllable lighting.

[00147] Light emitting sub-circuits 131 and 132 can be of many different types. In the embodiment indicated by indication arrow 152 of FIG. 3b, light emitting sub-circuits 13a and 132 are lamps 123 and 124, respectively. In this embodiment, lamps 123 and 124 each include a light emitting diode. More information regarding light emitting diodes is provided in the Background, as well as with some of the other drawings included herein.

[00148] Communication sub-circuit 134 can be of many different types. In the embodiment indicated by indication arrow 153 of FIG. 3b, communication sub-circuit 134 is a communication diode 105. Communication diode 105 can be of many different types, such as those included in remote controls, such as for a television. In the embodiment of indication arrow 153, communication diode 105 is in communication with controller circuit 1 10 through drive circuit 120. In this way, communication sub-circuit 134 is in communication with controller circuit 110 through drive circuit 120.

[00149] Communication diode 105 can provide many different frequency spectrums of light. As mentioned above, the frequency spectrum of light can be in the visible spectrum and the non-visible spectrum. The visible spectrum includes frequency spectrums detectable by the normal human eye and the non-visible spectrum includes frequency spectrums that are not detectable by the normal human eye. In general, the visible frequency spectrum includes light having a color of between red and violet, such as red, orange, green, blue, indigo and violet. The non-visible frequency spectrum includes light having a color of infrared and ultraviolet. In this embodiment, light emitting sub-circuits 131 and 132 provide light having a visible frequency spectrum, and communication diode 105 provides light having a non-visible frequency spectrum.

[00150] FIG. 3d is another embodiment of a load circuit, which is denoted as load circuit 130j. In this embodiment, load circuit 130j includes a lamp, denoted as lamp 131a, wherein lamp 131a carries light emitting sub-circuits 131 and 132, as well as communication sub- circuit 134. For illustrative purposes, light emitting sub-circuits 131 and 132 and communication sub-circuit 134 are indicated by corresponding broken lines in FIG. 3d. In this embodiment, light emitting sub-circuits 131 and 132 include diode strings D_A and D_B, respectively, and communication sub-circuit 134 includes a diode string D In general, diode strings DA, D_b and Dc each include one or more light emitting diode. Diode string D_c is shown as including one light emitting diode in FIG. 3d for simplicity, but it can include more than one light emitting diode, if desired.

[00151] FIG. 4a is a circuit diagram 101a of one embodiment of light emitting apparatus 100a of FIG. 3, which is denoted as light emitting apparatus 100b. In this embodiment, light emitting apparatus 100b includes load circuit 130, denoted as load circuit 130b, operatively coupled to controller circuit 1 10 through drive circuit 120. In this embodiment, drive circuit 120 includes drive input circuit 121 operatively coupled to controller circuit 1 10 and switching circuit 122 operatively coupled to drive input circuit 121 and load circuit 130b.

[00152] In this embodiment, controller circuit 1 10 includes a controller chip, which can be of many different types. One type of controller chip is a programmable logic unit. Controller chips are manufactured by many different companies, such as Microchip, Inc., Intel, Atmel and Freescale Semiconductor. Some names of these controller chips are the PIC microcontroller from Microchip, the 8051 microcontrollers from Intel, the AVR microcontrollers from Atmel and the 68C1 1 microcontrollers from Freescale Semiconductor. There is also the ARM microcontroller, which is provided by many different suppliers. [00153] In this embodiment, drive input circuit 121 includes transistors Qi and Q₂, which operate as switches, as will be discussed in more detail below. Transistors Q_\ and Q₂ can be of many different types. In this embodiment, transistors Qi and Q₂ are embodied as metal oxide field effect transistors (MOSFETs). A MOSFET includes a control terminal which controls the flow of a current between source and drain terminals.

[00154] In an n-type MOSFET (NMOS), the current flows between the source and drain terminals in response to driving a signal applied to the control terminal to a voltage level above a threshold voltage level, wherein the threshold voltage level has a positive voltage value. In the n-type MOSFET, the current does not flow between the source and drain terminals in response to driving the signal applied to the control terminal to a voltage level below the threshold voltage level. In this way, the n-type MOSFET operates as a switch.

[00155] In a p-type MOSFET (PMOS), the current flows between the source and drain terminals in response to driving a signal applied to the control terminal to a voltage level below a threshold voltage level, wherein the threshold voltage level has a negative voltage value. In the p-type MOSFET, the current does not flow between the source and drain terminals in response to driving the signal applied to the control terminal to a voltage level above the threshold voltage level. In this way, the p-type MOSFET operates as a switch. Examples of the circuit symbols typically used for NMOS and PMOS transistors are labeled and shown in FIG. 4a.

[00156] In this embodiment, the control terminal of transistor Oj is connected to a first output of controller circuit 110 so it receives a digital control signal Scomroii, and the control terminal of transistor Q₂ is connected to a second output of controller circuit 110 so it receives a digital control signal Scon_trou- In this embodiment, the source terminals of transistors Qi and Q₂ are connected to a reference terminal which applies a reference voltage VRef2, and the drain terminals of transistors Oj and Q₂ are connected to switching circuit 122 and provide drive input signals Si_nputi and S^p^, respectively.

[00157] In this embodiment, switching circuit 122 includes transistors Q₅ and Q₆, which operate as switches, as will be discussed in more detail below. Transistors Q₅ and Q₆ can be of many different types. In this embodiment, transistors Q₅ and Q₆ are embodied as MOSFETs.

[00158] In this embodiment, the control terminal of transistor Q₅ is connected to the drain of transistor Q₂ through a resistor R₂, and the control terminal of transistor Q₆ is connected to the drain of transistor Qi through a resistor R4. Further, the source of transistor Q₅ is connected to the drain of transistor Qi, and the source of transistor Q₆ is connected to the drain of transistor Q₂. In this embodiment, the drains of transistors Q₅ and Q₆ are connected to a reference terminal which applies a reference voltage VR_en. It should be noted that, in this embodiment, reference voltage VR_en is greater than reference voltage VR_CC. However, reference voltage V _en is less than reference voltage V_Ref2 in other embodiments.

[00159] It should be noted that, in general, transistors Qi and Q₂ are the same type of MOSFETS and transistors Q5 and Q₆ are the same type of MOSFETS. For example, in one embodiment, transistors Qi and Q₂ are NMOS transistors and transistors Q₅ and Q₆ are PMOS transistors. In another embodiment, transistors Qj and Q₂ are PMOS transistors and transistors Q$ and Q₆ are NMOS transistors. The type of transistors chosen depends on the relative voltage values between reference voltages VR_en and V_Ref2.

[00160] The control terminal of transistor Q₅ is connected, through a resistor Ri, to the terminal that applies reference voltage VR_efi_> and the control terminal of transistor Q₆ is connected, through a resistor R₃, to the terminal that applies reference voltage V_Ren . As will be discussed in more detail below, drive signal Sorive is provided to load circuit 130b between the sources of transistors Q₅ and Q₆.

[00161] The ratios of the resistance values of resistors R_\ and R₂ determine the voltage value of signal S^a when transistor Q₂ is active. Further, the ratios of the resistance values of resistors R₃ and R₄ determine the voltage value of signal Sin_putl when transistor Q₂ is active.

[00162] Resistors R_\, R₂, R₃ and R₄ can be of many different types. In some embodiments, resistors Ri, R₂, R₃ and R4 are resistors having predetermined resistance values and, in other embodiments, resistors Ri, R₂, R₃ and R4 are resistors having adjustable resistance values. An example of a resistor having an adjustable resistance value is a potentiometer.

[00163] In this embodiment, light emitting apparatus 100b includes an Diode string D_A which includes one or more LEDs connected in series. In this embodiment, the LEDs of string DA are denoted as diodes D_Ai, DA2, DA3 ..DAN, wherein N is a whole number greater than or equal to one. In this embodiment, light emitting apparatus 100b includes an Diode string DB which includes one or more LEDs connected in series. In this embodiment, the LEDs of string DB are denoted as diodes DB I, DB2, DB₃...DBM, wherein M is a whole number greater than or equal to one. It should be noted that, in some embodiments, N and M are equal and, in other embodiments, N and M are not equal. For example, in some embodiments, N is greater than M, in other embodiments, M is greater than N. It should be noted that a diode of diode string DA can be a silicon diode to reduce the likelihood of diode string D_A experiencing a reverse jump current.

[00164] In this embodiment, the LEDs of Diode string D_A are connected in series and each have the same polarity. The LEDs of Diode string D_A are connected in series and each have the same polarity because the terminal of one diode is connected to the opposed terminal of an adjacent diode. For example, the anode of diode D^ is connected to the cathode of diode D_Ai. Further, the cathode of diode D^ is connected to the anode of diode D_A3- It should be noted that the LEDs of Diode string D_A are connected in series and each have the same polarity so that they move between the active and deactive conditions together.

[00165] Further, in this embodiment, the LEDs of Diode string D_B are connected in series and each have the same polarity. The LEDs of Diode string D_B are connected in series and each have the same polarity because the terminal of one diode is connected to the opposed terminal of an adjacent diode. For example, the anode of diode D_B2 is connected to the cathode of diode D_{B I}. Further, the cathode of diode D_B2 is connected to the anode of diode D_B3- It should be noted that the light emitting diodes of Diode string D_B are connected in series and each have the same polarity so that they move between the active and deactive conditions together.

[00166] In this embodiment, light emitting sub-circuits 131 and 132 are connected in parallel so they have opposite polarities, as discussed in more detail above. Light emitting sub-circuits 131 and 132 are connected in parallel so they have opposite polarities because an anode of light emitting sub-circuit 131 is connected to a cathode of light emitting sub- circuit 132. The anode of light emitting sub-circuit 131 is connected to the cathode of light emitting sub-circuit 132 because the anode of Diode string D_A is connected to the cathode of diode string D_B. It should be noted that the anode of Diode string D_A corresponds to the anode of LED D_A1, and the cathode of Diode string D_B corresponds to the cathode of LED DBM-

[00167] Light emitting sub-circuits 131 and 132 are connected in parallel so they have opposite polarities because a cathode of light emitting sub-circuit 131 is connected to an anode of light emitting sub-circuit 132. The cathode of light emitting sub-circuit 131 is connected to the anode of light emitting sub-circuit 132 because the cathode of Diode string DA is connected to the anode of diode string DB- It should be noted that the cathode of Diode string DA corresponds to the cathode of LED DAN, and the anode of Diode string D_B corresponds to the anode of LED DBI .

[00168] In this embodiment, Diode strings D_A and DB provide first and second frequency spectrums of light in response to receiving a bipolar digital drive signal Some fr°^m switching circuit 122. The first and second frequency spectrums of light can be adjusted in response to adjusting bipolar digital drive signal Sorive- Bipolar digital drive signal Sorive can be adjusted in many different ways, such as by adjusting digital control signal Scon_troi- In this way, light emitting apparatus 100b provides controllable lighting.

[00169J In some embodiments, the amount of light provided by Diode string DA is adjustable in response to adjusting a duty cycle of drive signal Sorive- The amount of light provided by Diode string DA increases and decreases in response to increasing and decreasing, respectively, the duty cycle of drive signal Sorive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Scon_troi- In this way, light emitting apparatus 100b provides controllable lighting.

[00170] In some embodiments, the amount of light provided by Diode strings DB is adjustable in response to adjusting a duty cycle of drive signal Sorive- The amount of light provided by Diode strings DB increases and decreases in response to increasing and decreasing, respectively, the duty cycle of drive signal Sorive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Scon_troi- In this way, light emitting apparatus 100b provides controllable lighting.

[00171] It should be noted that an Diode string can include LEDs of the same type and different type. For example, in one embodiment, the Diode string includes diodes having the same diode threshold voltage values, such as twelve volts (12 V). In this way, the Diode string includes LEDs of same types. In another embodiment, the Diode string includes diodes having different diode threshold voltage values, such as twelve volts (12 V) and twenty-four volts (24 V). In this way, the Diode string includes LEDs of different types. [00172] FIG. 4b is a circuit diagram 101b of one embodiment of load circuit 130b of FIG. 4a, wherein N=5 and M=l so that diode string D_A includes five diodes D_Ai, D_A2, D_A3, DA4 and D_A5 connected in series and diode string D_B includes one diode D_{B I}. In this embodiment, diodes DA_I, DA2, D_A3, D_A4 and D_A5 are each the same types of diodes, although one or more of them can be different in other embodiments. In this embodiment, diodes DAI, D_A2, D_A3, D_A4 and D_A5 are each the same types of diodes because they emit the same spectrum of light.

[00173] In some embodiments, diodes D_AI, D_A2, D_A3, D_A4 and D_A5 have the same diode threshold voltage value. For example, in some embodiments, diodes D_AI, D_A2, D_A3, D_A4 and D_A5 each have a diode threshold voltage value of 4.8 volts. In this way, diodes D_A), DA2, DA3, D_a4 and D_A5 are each activated in response to driving the value of drive signal SDrive to be greater than or equal to 24 volts (i.e. more positive than or equal to 24 volts, such as 25 volts). Further, diodes D_AI, D_A2, D_A3, D_A4 and D_AS are each deactivated in response to driving the value of drive signal Sori_ve to be less than 24 volts (i.e. less positive than 24 volts, such as 23 volts).

[00174] In one embodiment, diodes D_Ai, D_A2, D_A3, D_A4 and D_A5 each have a diode threshold voltage value of 2.4 volts and diode D_{B I} has a diode threshold voltage value of 12 volts. In this way, diodes D_AI, D_A2, D_A3, D_A4 and D_AS are each activated in response to driving the value of drive signal Sori_ve to be greater than or equal to 12 volts (i.e. more positive than or equal to 12 volts, such as 13 volts), and diode D_BI is activated in response to driving the value of drive signal Sorive to be less than or equal to -12 volts (i.e. more negative than or equal to -12 volts, such as -13 volts). Further, diodes D_AI, D_A2, D_A3, D_A4 and D_AS are each deactivated in response to driving the value of drive signal Sorive to be less than 12 volts (i.e. less positive than 12 volts, such as 11 volts), and diode DB_I is deactivated in response to driving the value of drive signal Sori_ve to be greater than -12 volts (i.e. more positive than -12 volts, such as -11 volts). In this embodiment, drive signal Sori_ve can correspond to a bipolar digital signal. One example of a bipolar digital signal that can correspond to drive signal Sorive is shown in FIG. 2d, wherein V _AGI corresponds to 12 volts and VM_AG2 corresponds to -12 volts.

[00175] In another embodiment, diodes D_AI, D_A2, D_A3, D_A4 and D_AS each have a diode threshold voltage value of 4.8 volts and diode D_{B I} has a diode threshold voltage value of 8 volts. In this way, diodes D_Ai, D_A2, D_A3, DA₄ and D_A5 are each activated in response to driving the value of drive signal Sorive to be greater than or equal to 24 volts (i.e. more positive than or equal to 24 volts, such as 25 volts), and diode DBI is activated in response to driving the value of drive signal Sorive to be less than or equal to -8 volts (i.e. more negative than or equal to -8 volts, such as -9 volts). Further, diodes DAI, DA2, DA3, DA4 and DAS are each deactivated in response to driving the value of drive signal SDrive to be less than 24 volts (i.e. less positive than 24 volts, such as 23 volts), and diode DBI is deactivated in response to driving the value of drive signal Sorive to be greater than -8 volts (i.e. more positive than -8 volts, such as -7 volts). In this embodiment, drive signal Sorive can correspond to a bipolar digital signal. One example of a bipolar digital signal that corresponds to drive signal Sorive is shown in FIG. 2d, wherein VMAGI corresponds to 24 volts and V_MAG2 corresponds to -8 volts.

[00176J FIG. 4c is a circuit diagram lOld of another embodiment of load circuit 130b of

FIG. 4a, wherein N=5 and M=l so that diode string D_A includes five diodes DAI , DA , DA3, D_A4 and D_A5 connected in series and diode string DB includes one diode DBI. In this embodiment, load circuit 130b includes a diode string Dc, which includes a diode Dei so that L=l .

[00177J In this embodiment, diodes D_Ai, DA2, DA3, D_a4 and DAS are each the same types of diodes, although one or more of them can be different in other embodiments. In this embodiment, diodes DAI , DA2, DA3, D_a4 and D_A5 are each the same types of diodes because they emit the same spectrum of light.

[00178] In some embodiments, diodes DAI, DA , DA3, D_a4 and D_A5 have the same diode threshold voltage value. For example, in some embodiments, diodes DAI , DA2, DA3, D_A4 and DAS each have a diode threshold voltage value of 4.8 volts. In this way, diodes DAI, DA2, DA3, DA₄ and D_A5 are each activated in response to driving the value of drive signal Sorive to be greater than or equal to 24 volts (i.e. more positive than or equal to 24 volts, such as 25 volts). Further, diodes DAI, DA2, DA3, D_a4 and DAS are each deactivated in response to driving the value of drive signal SDrive to be less than 24 volts (i.e. less positive than 24 volts, such as 23 volts).

[00179] In one embodiment, diodes D_Ai, D^, DA3, D_a4 and D_A5 each have a diode threshold voltage value of 2.4 volts and diode DBI has a diode threshold voltage value of 12 volts. In this way, diodes D_Ai, DA₂, DA3, DA₄ and D_A5 are each activated in response to driving the value of drive signal Sorive to be greater than or equal to 12 volts (i.e. more positive than or equal to 12 volts, such as 13 volts), and diode DBI is activated in response to driving the value of drive signal Sorive to be less than or equal to -12 volts (i.e. more negative than or equal to -12 volts, such as -13 volts). Further, diodes D_Ai, DA2, DA3, D_A4 and DAS are each deactivated in response to driving the value of drive signal Sorive to be less than 12 volts (i.e. less positive than 12 volts, such as 1 1 volts), and diode DBI is deactivated in response to driving the value of drive signal Sorive to be greater than -12 volts (i.e. more positive than -12 volts, such as -1 1 volts). In this embodiment, drive signal Sorive can correspond to a bipolar digital signal. One example of a bipolar digital signal that can correspond to drive signal Sorive is shown in FIG. 2d, wherein VMAGI corresponds to 12 volts and VMAG2 corresponds to -12 volts.

[00180] In another embodiment, diodes DAI, DA2, DA3, D_a4 and DAS each have a diode threshold voltage value of 4.8 volts and diode DBI has a diode threshold voltage value of 8 volts. In this way, diodes DAI, DA2, DA3, DA₄ and DAS are each activated in response to driving the value of drive signal Sorive to be greater than or equal to 24 volts (i.e. more positive than or equal to 24 volts, such as 25 volts), and diode DBI is activated in response to driving the value of drive signal Sorive to be less than or equal to -8 volts (i.e. more negative than or equal to -8 volts, such as -9 volts). Further, diodes D_Ai, D_A2, DA3, DA4 and D_A5 are each deactivated in response to driving the value of drive signal Sorive to be less than 24 volts (i.e. less positive than 24 volts, such as 23 volts), and diode DBI is deactivated in response to driving the value of drive signal Sorive to be greater than -8 volts (i.e. more positive than -8 volts, such as -7 volts). In this embodiment, drive signal Sorive can correspond to a bipolar digital signal. One example of a bipolar digital signal that corresponds to drive signal Sorive is shown in FIG. 2d, wherein VMAGI corresponds to 24 volts and VMAG2 corresponds to -8 volts.

[00181] In this embodiment, diode string Dc is connected in parallel with diode strings D_A and DB. The cathode of diode Dei is connected to the anode of diode DBI and the anode of diode Dei is connected to the cathode of diode DBI. In operation, diode Dei emits light when diode string DA emits light, and diode Da does not emit light when diode string D_A does not emit light. Further, diode Da emits light when diode string DA does not emit light, and diode Da does not emit light when diode string D_A does emit light.

[00182] In some embodiments, diode string Dc emits the same frequency spectrum of light as diode string DA, and, in other embodiments, diode string Dc emits a different frequency spectrum of light from diode string DA- In some embodiments, the frequency spectrum of light emitted by diode string Dc corresponds to visible light. In other embodiments, the frequency spectrum of light emitted by diode string Dc corresponds to non-visible light. For example, in some embodiments, the frequency spectrum of light emitted by diode string Dc corresponds to infrared light. In other embodiments, the frequency spectrum of light emitted by diode string Dc corresponds to ultraviolet light.

[00183] FIG. 4d is a circuit diagram of another embodiment of light emitting apparatus 100a of FIG. 4a. In this embodiment, a diode string Dc is connected in parallel with diode strings D_A and DB, wherein diode string Dc provides light 104. Light 104 can be of many different types, such as visible light and non-visible light. More information regarding visible light and non-visible light is provided in more detail above. In one particular embodiment, diode string Dc includes a LED which provides infrared light. Diode string Dc can be used to proved optical pulses for optical communication with a remote device, wherein the remote device is not shown.

[00184] FIG. 4e is a circuit diagram lOlf of another embodiment of a load circuit 130b of FIG. 4a, which is denoted as load circuit 130i, wherein N=5 and M=l so that diode string D_A includes five diodes D_Ai, DA2, DA3, D_a4 and D_A5 connected in series and diode string D_B includes one diode DBI- In this embodiment, load circuit 130b includes a diode string Dc, which includes a diode Dei so that L=l . This embodiment of circuit diagram lOlf is similar to circuit diagram 101 d of FIG. 4c. In this embodiment, however, load circuit 130i includes a switch 1 13a connected in series with diode string D_A, a switch 113b connected in series with diode string DB and a switch 1 13c connected in series with diode string Dc. Switches 1 13a, 1 13b and 1 13 are operatively coupled to a controller circuit 110a, which can be the same or similar to controller circuit 1 10. In some embodiments, controller circuit 110a is a portion of controller circuit 1 10, so that controller circuit 1 10a is included with controller circuit 1 10.

[00185] In this embodiment, the operation of diode string D_A is adjustable in response to receiving an indication from controller circuit 1 10a. The indication can be of many different types. In this embodiment, the indication corresponds to control signal ScontroD, which flows between controller circuit 1 10a and switch 1 13a through conductive line 128. In some embodiments, control signal ScontroD is a wireless signal. Diode string D_A is repeatably moveable between active and deactive conditions in response to adjusting control signal Sc₀ntroi3- In the active condition, current flows though diode string D_A in response to establishing drive signal Sorive and, in the deactive condition, current does not flow though diode string D_A in response to establishing drive signal Sorive-

[00186] In this embodiment, the operation of diode string DB is adjustable in response to receiving an indication from controller circuit 1 10a. The indication can be of many different types. In this embodiment, the indication corresponds to control signal Scon_trow, which flows between controller circuit 1 10a and switch 1 13b through conductive line 129. In some embodiments, control signal ScontroM is a wireless signal. Diode string DB is repeatably moveable between active and deactive conditions in response to adjusting control signal Scon_trow- In the active condition, current flows though diode string D_B in response to establishing drive signal Sorive and, in the deactive condition, current does not flow though diode string DB in response to establishing drive signal Sorive-

[00187] In this embodiment, the operation of diode string Dc is adjustable in response to receiving an indication from controller circuit 1 10a. The indication can be of many different types. In this embodiment, the indication corresponds to control signal Scontroi9, which flows between controller circuit 110a and switch 1 13c through a conductive line 129a. In some embodiments, control signal Sc_ontroi9 is a wireless signal. Diode string Dc is repeatably moveable between active and deactive conditions in response to adjusting control signal Scon_troi9- In the active condition, current flows though diode string Dc in response to establishing drive signal Sorive and, in the deactive condition, current does not flow though diode string Dc in response to establishing drive signal Sorive-

[00188] It should be noted that, in general, one or more of switches 1 13a, 1 13b and 1 13c can be in the active condition. For example, in one situation switches 1 13a and 1 13b are in the active condition and switch 1 13c is in the deactive condition. In another situation, switches 1 13a and 1 13b are in the deactive condition and switch 1 13c is in the active condition. In this way, the frequency spectrum of light provided by load circuit 130i is adjustable in response to adjusting a control signal.

[00189] FIG. 5a is a circuit diagram 101c of another embodiment of light emitting apparatus 100a of FIG. 3, which is denoted as light emitting apparatus 100c. In this embodiment, light emitting apparatus 100c includes load circuit 130, denoted as a load circuit 130c, operatively coupled to controller circuit 110 through drive circuit 120. In this embodiment, drive circuit 120 includes drive input circuit 121 operatively coupled to controller circuit 1 10 and switching circuit 122 operatively coupled to drive input circuit 121 and load circuit 130c.

[00190] In this embodiment, drive input circuit 121 includes transistors Qi and Q₂, which operate as switches, as will be discussed in more detail below. Transistors i and Q₂ can be of many different types. In this embodiment, transistors Qi and Q₂ are embodied as MOSFETs.

[00191] In this embodiment, the control terminal of transistor Qi is connected to a first output of controller circuit 110 so it receives a digital control signal Scontroii, and the control terminal of transistor Q₂ is connected to a second output of controller circuit 1 10 so it receives a digital control signal Scontroi3- In this embodiment, the source terminals of transistors Qi and Q₂ are connected to a reference terminal which applies reference voltage Ref2, and the drain terminals of transistors Qi and Q₂ are connected to switching circuit 122 and provide drive input signals Sinp_Utl and Sin_pue, respectively.

[00192] In this embodiment, switching circuit 122 includes transistors Q₅ and Q₆, which operate as switches, as will be discussed in more detail below. Transistors Q₅ and Q₆ can be of many different types. In this embodiment, transistors Q₅ and Q are embodied as MOSFETs.

[00193] In this embodiment, the control terminal of transistor Q₅ is connected to an output of controller circuit 110 so it receives a digital control signal Sc_ontroi2 and the control terminal of transistor Q₆ is connected to an output of controller circuit 1 10 so it receives a digital control signal Scontrow- Further, the source of transistor Q₅ is connected to the drain of transistor Qj. In this embodiment, the sources of transistors Q₂, Q₅ and Q₆ are connected to load circuit 130c, as will be discussed in more detail below. In this embodiment, the drains of transistors Q₅ and Q₆ are connected to a reference terminal which applies a reference voltage VR_en . It should be noted that, in this embodiment, reference voltage VR_en is greater than reference voltage VR_ef2. However, reference voltage V _en is less than reference voltage VR_CO in other embodiments. As will be discussed in more detail below, more than one drive signal is provided by switching circuit 122 to load circuit 130c.

[00194] In this embodiment, load circuit 130c includes light emitting sub-circuits 131, 132 and 133. In this embodiment, light emitting sub-circuit 131 includes Diode string D_A which includes one or more LEDs connected in series. In this embodiment, the LEDs of string DA are denoted as diodes D_AI, DA2, DA3...D_AN, wherein N is a whole number greater than or equal to one.

[00195] In this embodiment, light emitting sub-circuit 132 includes an Diode string DB which includes one or more LEDs connected in series. In this embodiment, the LEDs of string DB are denoted as diodes D_{B I}, D_B2, DB₃...D_BM5 wherein M is a whole number greater than or equal to one. In this embodiment, light emitting sub-circuit 133 includes an Diode string Dc which includes one or more LEDs connected in series.

{00196] In this embodiment, the LEDs of string Dc are denoted as diodes Dei, Dc2, D_C3-..DBL, wherein L is a whole number greater than or equal to one. It should be noted that, in some embodiments, N and M are equal and, in other embodiments, N and M are not equal. In some embodiments, N and L are equal and, in other embodiments, N and L are not equal. Further, in some embodiments, M and L are equal and, in other embodiments, M and L are not equal.

[00197] In this embodiment, the LEDs of Diode string D_A are connected in series and each have the same polarity. The LEDs of Diode string D are connected in series and each have the same polarity because the terminal of one diode is connected to the opposed terminal of an adjacent diode. For example, the anode of diode D_A2 is connected to the cathode of diode D_Ai . Further, the cathode of diode D_A2 is connected to the anode of diode D_A3- It should be noted that the LEDs of Diode string D_A are connected in series and each have the same polarity so that they move between the active and deactive conditions together.

[00198] Further, in this embodiment, the LEDs of Diode string D_B are connected in series and each have the same polarity. The LEDs of Diode string D_B are connected in series and each have the same polarity because the terminal of one diode is connected to the opposed terminal of an adjacent diode. For example, the anode of diode D_B2 is connected to the cathode of diode D_{B I}. Further, the cathode of diode D_B2 is connected to the anode of diode DB₃- It should be noted that the light emitting diodes of Diode string D_B are connected in series and each have the same polarity so that they move between the active and deactive conditions together.

[00199] In this embodiment, the LEDs of Diode string Dc are connected in series and each have the same polarity. The LEDs of Diode string Dc are connected in series and each have the same polarity because the terminal of one diode is connected to the opposed terminal of an adjacent diode. For example, the anode of diode Dc₂ is connected to the cathode of diode Dei- Further, the cathode of diode Dc₂ is connected to the anode of diode Dc3- It should be noted that the LEDs of Diode string Dc are connected in series and each have the same polarity so that they move between the active and deactive conditions together.

[00200] In this embodiment, the anode of Diode string D_A is connected to an anode of Diode string Dc, and the anodes of Diode strings D_A and D_c are connected to the drain of transistor Qj and the source of transistor Q₆. In this embodiment, the cathode of Diode string DB is connected to the cathode of Diode string Dc and the drain of transistor Qi and the source of transistor Q₅, and the anode of diode string DB is connected to the cathode of diode string D_A and the drain of transistor Q₂. In this embodiment, the cathode of Diode string DB is connected to the cathode of Diode string Dc and the drain of transistor Qi and the source of transistor Q₅.

[00201] In this embodiment, Diode strings D_A, D_B and Dc provide first, second and third frequency spectrums of light, respectively, in response to receiving a bipolar digital drive signal S Drive &om switching circuit 122. The first, second and third frequency spectrums of light can be adjusted in response to adjusting bipolar digital drive signal Sorive- Bipolar digital drive signal Sorive can be adjusted in many different ways, such as by adjusting digital control signal Scontroi- In this way, light emitting apparatus 100c provides controllable lighting.

[00202] In some embodiments, the amount of light provided by Diode string D_A is adjustable in response to adjusting a duty cycle of drive signal Sorive- The amount of light provided by Diode string D_A increases and decreases in response to increasing and decreasing, respectively, the duty cycle of drive signal Sorive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Scon_troi- In this way, light emitting apparatus 100c provides controllable lighting.

[00203] In some embodiments, the amount of light provided by Diode strings D_B is adjustable in response to adjusting a duty cycle of drive signal Sorive- The amount of light provided by Diode strings D_B increases and decreases in response to increasing and decreasing, respectively, the duty cycle of drive signal Sorive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Sco_ntroi- In this way, light emitting apparatus 100c provides controllable lighting.

[00204] In some embodiments, the amount of light provided by Diode strings Dc is adjustable in response to adjusting a duty cycle of drive signal Some- The amount of light provided by Diode strings Dc increases and decreases in response to increasing and decreasing, respectively, the duty cycle of drive signal Sorive- The duty cycle of drive signal Sorive can be adjusted in many different ways, such as by adjusting the duty cycle of digital control signal Scontroi- In this way, light emitting apparatus 100c provides controllable lighting.

[00205] FIG. 5b is a circuit diagram of one embodiment of load circuit 130c of FIG. 5a, wherein N=3 and M=2 and L=l so that diode string D_A includes three diodes D_Ai, DA2 and DA3 connected in series and diode string DB includes two diodes DBI and DB₂ connected in series and diode string Dc includes one diode Dei- In this embodiment, diodes DAI, D_A2 and D A3 are each the same types of diodes, although one or more of them can be different in other embodiments. In this embodiment, diodes D_Ai, DA2 and DA3 are each the same types of diodes because they emit the same spectrum of light. In this embodiment, diodes D_&\ and DB2 are each the same types of diodes, although one or more of them can be different in other embodiments. In this embodiment, diodes DBI and D_B2 are each the same types of diodes because they emit the same spectrum of light. In this embodiment, diodes DBI and DB₂ are each the same types of diodes, although one or more of them can be different in other embodiments.

[00206] In some embodiments, diodes DAI, D_a2 and DA3 are the same types of diodes as diodes DBI and DB₂, although they can be different types in other embodiments. In some embodiments, diodes DAI, DA2 and DA3 are the same types of diodes as diode Dci, although they can be different types in other embodiments. In some embodiments, diodes DBI and DB2 are the same types of diodes as diode Dci, although they can be different types in other embodiments.

[00207] In some embodiments, diodes DAI , DA2 and DA3 have the same diode threshold voltage value. For example, in some embodiments, diodes D_Ai, DA2 and DA3 each have a diode threshold voltage value of 8 volts. In this way, diodes D_Ai, DA2 and DA3 are each activated in response to driving the value of drive signal So_rive2 to be greater than or equal to 24 volts (i.e. more positive than or equal to 24 volts, such as 25 volts). Further, diodes DAI, DA2 and DA3 are each deactivated in response to driving the value of drive signal SDrive2 to be less than 24 volts (i.e. less positive than 24 volts, such as 23 volts).

[00208] In one embodiment, diodes D_A1, DA2 and DA3 each have a diode threshold voltage value of 4 volts and diodes DBI and DB₂ each have a diode threshold voltage value of 6 volts and diode Dei has a diode threshold voltage value of 12 volts. In this way, diodes DAI, DA2 and DA3 are each activated in response to driving the value of drive signal Sorive2 to be greater than or equal to 12 volts (i.e. more positive than pr equal to 12 volts, such as 13 volts), and diodes DBI and DB₂ are activated in response to driving the value of drive signal SDrive3 to be less than or equal to -12 volts (i.e. more negative than or equal to - 12 volts, such as - 13 volts) and diode Dei is activated in response to driving the value of drive signal SDrivei to be less than or equal to -12 volts (i.e. more negative than or equal to -12 volts, such as - 13 volts). Further, diodes DAI, DA2 and DA are each deactivated in response to driving the value of drive signal Sorive2 to be less than 12 volts (i.e. less positive than 12 volts, such as 1 1 volts), and diodes DBI and DB2 are deactivated in response to driving the value of drive signal Sonve3 to be greater than -12 volts (i.e. more positive than - 12 volts, such as -1 1 volts) and diode D_Ci is deactivated in response to driving the value of drive signal Sorivei to be greater than - 12 volts (i.e. more positive than - 12 volts, such as -1 1 volts). In this embodiment, drive signals Sorivei, Sorive2 and Sorive3 can each correspond to a bipolar digital signal.

[00209] One example of a bipolar digital signal that can correspond to drive signals Sorivei , Sorive2 and SDrive3 is shown in FIG. 2d. Drive signals SDrivei can correspond to a first version of bipolar digital signal SDC3 wherein VMAGI corresponds to 12 volts and VMAG2 corresponds to - 12 volts. Drive signals Sorive2 can correspond to a second version of bipolar digital signal SDC3 wherein VMAGI corresponds to 12 volts and VMAG2 corresponds to -12 volts. Drive signals Sorive3 can correspond to a third version of bipolar digital signal SDC3 wherein VMAGI corresponds to 12 volts and VMAG2 corresponds to -12 volts.

[00210] In another embodiment, diodes DAI, DA2 and DA3 each have a diode threshold voltage value of 5 volts and diodes

and DB₂ each have a diode threshold voltage value of 4 volts and diode Dei has a diode threshold voltage value of 6 volts. In this way, diodes DAI, DA2 and DA3 are each activated in response to driving the value of drive signal Sorive2 to be greater than or equal to 15 volts (i.e. more positive than or equal to 15 volts, such as 16 volts), and diodes DBI and DB₂ are activated in response to driving the value of drive signal SDrive3 to be less than or equal to -8 volts (i.e. more negative than or equal to -8 volts, such as -9 volts) and diode Dci is activated in response to driving the value of drive signal SDrivei to be less than or equal to -6 volts (i.e. more negative than or equal to -6 volts, such as -7 volts).

[00211] Further, diodes D_Ai, DA2 and DA3 are each deactivated in response to driving the value of drive signal Sorive2 to be less than 24 volts (i.e. less positive than 24 volts, such as 23 volts), and diode DBI is deactivated in response to driving the value of drive signal Sorive3 to be greater than -8 volts (i.e. more positive than -8 volts, such as -7 volts) and diode Dci is deactivated in response to driving the value of drive signal Sorivei to be greater than -6 volts (i.e. more positive than -6 volts, such as -5 volts).

[00212] One example of a bipolar digital signal that can correspond to drive signals SDrivei, Sorive2 and Sorive3 is shown in FIG. 2d. Drive signals Sorive2 can correspond to a first version of bipolar digital signal SDC3 wherein V AGI corresponds to 15 volts and VMAG2 corresponds to -15 volts. Drive signals Sorive3 can correspond to a second version of bipolar digital signal SDC3 wherein VMAGI corresponds to 8 volts and V AG2 corresponds to -8 volts. Drive signals Sorive3 can correspond to a third version of bipolar digital signal SDC3 wherein VMAGI corresponds to 6 volts and VMAG2 corresponds to -6 volts.

[00213] FIG. 6a is a circuit diagram of another embodiment of light emitting apparatus 100a of FIG. 3, which is denoted as circuit diagram lOOd. In this embodiment, light emitting apparatus lOOd includes load circuit 130, denoted as a load circuit 130d, operatively coupled to controller circuit 1 10 through drive circuit 120. In this embodiment, drive circuit 120 includes drive input circuit 121 operatively coupled to controller circuit 1 10 and switching circuit 122 operatively coupled to drive input circuit 121 and load circuit 130d.

[00214] In this embodiment, drive input circuit 121 includes transistors Qj, Q₂ and Q₃, which operate as switches, as will be discussed in more detail below. Transistors Qi, Q₂ and Q₃ can be of many different types. In this embodiment, transistors Qi, Q₂ and Q₃ are embodied as MOSFETs.

[00215] In this embodiment, the control terminal of transistor Qj is connected to the first output of controller circuit 1 10 so it receives a digital control signal Scontroii , and the control terminal of transistor Q₂ is connected to the third output of controller circuit 110 so it receives a digital control signal Scontroi3 and the control terminal of transistor Q₃ is connected to a fifth output of controller circuit 1 10 so it receives a digital control signal Scontroi5- In this embodiment, the source terminals of transistors Qi , Q₂ and Q3 are connected to the reference terminal which applies reference voltage NReo, and the drain terminals of transistors Qi, Q₂ and Q₃ are connected to switching circuit 122 and provide drive input signals S input], ]n_pu and Sinp_Ut3, respectively.

[00216] In this embodiment, switching circuit 122 includes transistors Q₄, Q₅ and Q , which operate as switches, as will be discussed in more detail below. Transistors Q₄, Q₅ and Q can be of many different types. In this embodiment, transistors Q₄, Q and Q₆ are embodied as MOSFETs.

[00217] In this embodiment, the control terminal of transistor Q₄ is connected to an output of controller circuit 1 10 so it receives the digital control signal Scontroi2, the control terminal of transistor Q₅ is connected to an output of controller circuit 1 10 so it receives a digital control signal Scon_trow and the control terminal of transistor Q₆ is connected to an output of controller circuit 1 10 so it receives a digital control signal Scontroi6- [00218] Further, the source of transistor Q₄ is connected to the drain of transistor Qi, the source of transistor Q₅ is connected to the drain of transistor Q₂ and the source of transistor Q₆ is connected to the drain of transistor Q₃. In this embodiment, the sources of transistors Q₄, Q₅ and Q are connected to load circuit 130d, as will be discussed in more detail below.

[00219] It should be noted that drive input circuit 121 provides drive input signals S_lnputi, Stnput. and Sfoputf to switching circuit 122, wherein drive input signals Sin_puti flows between the drain of transistor Qi and the source of transistor Q₄, drive input signals Si_nput2 flows between the drain of transistor Q₂ and the source of transistor Q₅ and drive input signals Sinput3 flows between the drain of transistor Q₃ and the source of transistor Q₆.

[00220] In this embodiment, the drains of transistors Q₄, Q and Q₆ are connected to the reference terminal which applies the reference voltage V _en - It should be noted that, in this embodiment, reference voltage VR_en is greater than reference voltage V_Ref2. However, reference voltage VR_en is less than reference voltage VR_ef2 in other embodiments. As will be discussed in more detail below, more than one drive signal is provided by switching circuit 122 to load circuit 130d.

[00221] In this embodiment, load circuit 130d includes light emitting sub-circuits 135, 136 and 137. It should be noted that light emitting sub-circuits 135, 136 and 137 can each include an Diode string, as described in more detail above with FIG. 4a. For example, in this embodiment, light emitting sub-circuit 135 includes Diode strings DA and Dp connected in parallel. Further, light emitting sub-circuit 136 includes Diode strings DB and DE connected in parallel and light emitting sub-circuit 137 includes Diode strings Dc and Dp connected in parallel. It should be noted that Diode strings DA and Dp are connected in parallel in the same manner as described above in FIG. 4a, Diode strings DB and DE are connected in parallel in the same manner as described above in FIG. 4a and Diode strings Dc and Dp are connected in parallel in the same manner as described above in FIG. 4a.

[00222] In this embodiment, light emitting sub-circuit 135 is connected to the source of transistor Q₅ so that the anode of Diode string D_A is connected to the source of transistor Q₅ and the cathode of Diode string Do is connected to the source of transistor Q₅. As mentioned above, the source of transistor Q₅ is connected to the drain of transistor Q₂. Hence, the anode of Diode string D_A is connected to the drain of transistor Q₂ and the cathode of Diode string Do is connected to the drain of transistor Q₂.

[00223] In this embodiment, light emitting sub-circuit 135 is connected to the drain of transistor Q₃ so that the cathode of Diode string D_A is connected to the drain of transistor Q₃ and the anode of Diode string Do is connected to the drain of transistor Q₃. As mentioned above, the drain of transistor Q₃ is connected to the source of transistor Q₆. Hence, the cathode of Diode string DA is connected to the source of transistor Q₆ and the anode of Diode string Do is connected to the source of transistor Q₆.

[00224] In this embodiment, light emitting sub-circuit 136 is connected to the source of transistor Q₄ so that the anode of Diode string DE is connected to the source of transistor Q₄ and the cathode of Diode string DB is connected to the source of transistor Q₄. As mentioned above, the drain of transistor Qi is connected to the source of transistor Q₄. Hence, the anode of Diode string DE is connected to the drain of transistor Qi and the cathode of Diode string DB is connected to the drain of transistor Qi .

[00225] In this embodiment, light emitting sub-circuit 136 is connected to the drain of transistor Q₃ so that the anode of Diode string DB is connected to the drain of transistor Q₃ and the cathode of Diode string DE is connected to the drain of transistor Q₄. As mentioned above, the drain of transistor Q₃ is connected to the source of transistor Q₆. Hence, the anode of Diode string DB is connected to the drain of transistor Q₃ and the cathode of Diode string DE is connected to the drain of transistor Q₄. [00226] In this embodiment, light emitting sub-circuit 137 is connected to the source of transistor Q₄ so that the anode of Diode string Dp is connected to the source of transistor Q₄ and the cathode of Diode string Dc is connected to the source of transistor Q₄. As mentioned above, the drain of transistor Qi is connected to the source of transistor Q . Hence, the anode of Diode string Dp is connected to the drain of transistor Qj and the cathode of Diode string Dc is connected to the drain of transistor Qi.

[00227] In this embodiment, light emitting sub-circuit 137 is connected to the source of transistor Q₅ so that the cathode of Diode string DF is connected to the source of transistor Q₅ and the anode of Diode string Dc is connected to the source of transistor Q . As mentioned above, the drain of transistor Q₂ is connected to the source of transistor Q₅. Hence, the cathode of Diode string Dp is connected to the drain of transistor Q₂ and the anode of Diode string Dc is connected to the drain of transistor Q₂.

[00228] FIG. 6b is a circuit diagram of one embodiment of load circuit 130c of FIG. 6a, wherein N=2 and M=3 and L=2 so that diode string DA includes two diodes D_Ai and DA_ connected in series and diode string DB includes three diodes DBI , DB₂ and DB₃ connected in series and diode string Dc includes two diodes Dci and D^. Further, in this embodiment of load circuit 130c, P=3 and Q=l and R=2 so that diode string Do includes three diodes DDI, DQ₂ and D_D3 connected in series and diode string DE includes one diode DEI and diode string DF includes two diodes DFI and Dp₂ connected in series.

[00229] In this embodiment, diodes DAI and DA_ are each the same types of diodes, although one or more of them can be different in other embodiments. In some embodiments, diodes DAI and DA2 have the same diode threshold voltage value. For example, in some embodiments, diodes DAI and DA2 each have a diode threshold voltage value of 8 volts. In one embodiment, diodes DAI and DA₂ each have a diode threshold voltage value of 4 volts and diodes DBI and DB₂ each have diode threshold voltage values of 6 volts and diodes Dci and Dc₂ each have a diode threshold voltage value of 12 volts. In other embodiments, diodes DAI and DA2 have different diode threshold voltage values.

[00230] In this embodiment, diodes D_Bi, DB₂ and D_B3 are each the same types of diodes, although one or more of them can be different in other embodiments. In some embodiments, diodes DBI, DB₂ and DB3 have the same diode threshold voltage value. For example, in some embodiments, diodes DBI, DB₂ and DB₃ each have a diode threshold voltage value of 12 volts. In one embodiment, diodes DBI , DB₂ and DB₃ each have a diode threshold voltage value of 6 volts and diodes DAI and DA₂ each have diode threshold voltage values of 4 volts and diodes Da and Dc₂ each have a diode threshold voltage value of 12 volts. In other embodiments, diodes DBI and DB₂ have different diode threshold voltage values.

[00231] In this embodiment, diodes Dei and Dc₂ are each the same types of diodes, although one or more of them can be different in other embodiments. In some embodiments, diodes Dei and Dc₂ have the same diode threshold voltage value. For example, in some embodiments, diodes Dei and Dc₂ each have a diode threshold voltage value of 12 volts. In one embodiment, diodes Dei and Dc₂ each have a diode threshold voltage value of 6 volts and diodes DAI and DA₂ each have diode threshold voltage values of 4 volts and diodes DBI, DB₂ and DB₃ each have a diode threshold voltage value of 12 volts.

[00232] In other embodiments, diodes Dei and Dc₂ have different diode threshold voltage values, so that diodes DC1 and DC2 are activated in response to different amplitude signals. Signals having different amplitudes are discussed in more detail above, as well as below with FIGS. 10a, 10b, 10c and lOd.

[00233] FIG. 7 is a circuit diagram of one embodiment of a light emitting apparatus lOOf. In this embodiment, light emitting apparatus lOOf includes a load circuit 13 Of operatively coupled to controller circuit 1 10 (not shown) through a drive circuit 120f. Drive circuit 120f provides drive signal Sohve to load circuit 13 Of in response to receiving control signals ScontroJi, Scontroi2, S_Controi3 and S_Comroi4 from controller circuit 1 10.

[00234] In this embodiment, drive circuit 120f includes transistors Qj, Q₂, Q₃ and Q₄, which operate as switches, as will be discussed in more detail below. Transistors Qi, Q₂, Q₃ and Q₄ are operatively coupled to load circuit 130d. Transistors Qi, Q₂, Q₃ and Q₄ can be of many different types. In this embodiment, transistors Q_ls Q₂, Q₃ and Q are embodied as MOSFETs.

[00235] In this embodiment, the control terminal of transistor Q_\ is connected to the first output of controller circuit 1 10 so it receives digital control signal Scomroii, the control terminal of transistor Q₂ is connected to the second output of controller circuit 1 10 so it receives digital control signal Sc₀ntroi2, the control terminal of transistor Q₃ is connected to a third output of controller circuit 110 so it receives a digital control signal Sc₀ntroi3 and the control terminal of transistor Q₃ is connected to a fourth output of controller circuit 1 10 so it receives digital control signal Sc_ontroi4- [00236] In this embodiment, the source terminals of transistors Q_ls Q₂, Q₃ and Q4 are connected to separate reference terminals which apply reference voltages V_REF3J VR_ef4, -VR_CG and -VRef₄, respectively. Further, the drain terminals of transistors Qi and Q4 are connected together and to load circuit 13 Of, and the drain terminals of transistors Q₂ and Q₃ are connected together and to load circuit 130f.

[00237] In this embodiment, load circuit 130f includes a light emitting sub-circuit 138, which includes diode DAI- It should be noted that, in general, light emitting sub-circuit 138 can include one or more diodes. However, light emitting sub-circuit 138 includes one diode in this embodiment for illustrative purposes. Diode D_Ai includes an anode connected to the drains of transistors Q₂ and Q₃ and a cathode connected to the drains of transistors Qi and Q₄.

[00238] In this embodiment, load circuit 130f includes a light emitting sub-circuit 139, which includes diodes DBI, DB₂ and DB₃. It should be noted that, in general, light emitting sub-circuit 138 can include one or more diodes. However, light emitting sub-circuit 138 includes three diodes in this embodiment for illustrative purposes. Diodes DBI, DB₂ and D_B3 are connected in series so that the cathode of diode DBI is connected to the anode of diode DB₂, and the cathode of diode DB₂ is connected to the anode of diode DB₃. Further, the cathode of diode DB₃ is connected to the drains of transistors Q₂ and Q₃. In this way, diodes DBI , DB₂ and DB₃ are connected in series.

[00239] In this embodiment, light emitting sub-circuits 138 and 139 are connected in reverse parallel. Light emitting sub-circuits 138 and 139 are connected in reverse parallel so that the anode of diode DBI is connected to the cathode of transistor D_Ai and the cathode of transistor DB₃ is connected to the anode of transistor DAI- In this way, light emitting sub- circuits 138 and 139 are connected in reverse parallel.

[00240] In this embodiment, the anode of diode DBI and the cathode of transistor D_Ai are connected to the drains of

and Q4 and the cathode of transistor DB₃ and the anode of transistor D_Ai are connected to the drains of transistors Q₂ and Q₃. In this way, load circuit 130f is connected to drive circuit 120f.

[00241] In this embodiment, the diodes of light emitting sub-circuit 139 are the same types of diodes because diodes DBI , DB₂, and DB₃ are the same types of diodes. However, in other embodiments, one or more of diodes DBI, DB₂, and DB₃ are different. For example, in one embodiment, diode DBI and DB₂ are the same types of diodes and diode DB₃ is a different type of diode from diodes DBI and DB₂. In some embodiments, diode DAI is the same type of diode as diodes D_B1, DB₂, and DB₃. However, in other embodiments, diode DAI is a different type of diode from diodes DBI, DB₂, and DB₃.

[00242] In some embodiments, diodes DBI, DB₂ and DB₃ have the same diode threshold voltage value. For example, in some embodiments, diodes DBI, DB₂ and DB₃ each have a diode threshold voltage value of 8 volts. In this way, diodes DBI, DB₂ and DB₃ are each activated in response to driving the value of drive signal Sorive to be greater than or equal to 24 volts (i.e. more positive than or equal to 24 volts, such as 25 volts). Further, diodes DBI, DB₂ and DB₃ are each deactivated in response to driving the value of drive signal Sorive to be less than 24 volts (i.e. less positive than 24 volts, such as 23 volts).

[00243] In one embodiment, diodes D_B1, DB₂ and DB₃ each have a diode threshold voltage value of 4 volts and diode D_Ai has a diode threshold voltage value of 6 volts. In this way, diodes DB₂ and DB₃ are each activated in response to driving the value of drive signal SDrive to be greater than or equal to 12 volts (i.e. more positive than pr equal to 12 volts, such as 13 volts), and diode D_Ai is activated in response to driving the value of drive signal SDrive to be less than or equal to -6 volts (i.e. more negative than or equal to -6 volts, such as -7 volts). Further, diodes DBI , DB₂ and DB₃ are each deactivated in response to driving the value of drive signal Sorive to be less than 12 volts (i.e. less positive than 12 volts, such as 1 1 volts), and diode D_A1 is deactivated in response to driving the value of drive signal Sorive to be greater than -6 volts (i.e. more positive than -6 volts, such as -5 volts). In this embodiment, drive signal Sorive can correspond to a bipolar digital signal, as will be discussed in more detail presently.

[00244] One example of a bipolar digital signal that can correspond to drive signal Sorive is shown in FIG. 2d. Drive signal Sorive can correspond to a version of bipolar digital signal Soc3 wherein VMAGI corresponds to 12 volts and VMAG2 corresponds to -12 volts.

[00245] In another embodiment, diodes DBI, DB₂ and DB₃ each have a diode threshold voltage value of 5 volts and diode D_Ai has a diode threshold voltage value of 4 volts. In this way, diodes DAI , DA2 and ΌΑΙ are each activated in response to driving the value of drive signal Sorive2 to be greater than or equal to 15 volts (i.e. more positive than or equal to 15 volts, such as 16 volts), and diode D_Ai is activated in response to driving the value of drive signal Sorive3 to be less than or equal to -5 volts (i.e. more negative than or equal to -5 volts, such as -6 volts). [00246] Further, diodes DBI, DB₂ and DB₃ are each deactivated in response to driving the value of drive signal Sorive3 to be less than 15 volts (i.e. less positive than 15 volts, such as 14 volts), and diode DAI is deactivated in response to driving the value of drive signal Sorive3 to be greater than -5 volts (i.e. more positive than -5 volts, such as -4 volts).

[00247] FIG. 8a is a circuit diagram of one embodiment of a light emitting apparatus lOOg. In this embodiment, light emitting apparatus l OOg includes transistors Q₇ and Q₈, which operate as switches, as will be discussed in more detail below. Transistors Q₇ and Q₈ can be of many different types. In this embodiment, transistors Q₇ and Q₈ are embodied as MOSFETs.

[00248] In this embodiment, the source of transistor Q₇ is connected to the first output of controller circuit 1 10 (not shown) so it receives digital control signal Scontroii, and the control terminal of transistor Q₈ is connected to the first output of controller circuit 1 10 (not shown) through resistor R₂ so it receives digital control signal Scontroii - In some embodiments, resistor R₃ is connected between the source of transistor Q₇ and the first output of controller circuit 1 10 that provides digital control signal Scontroi as indicated by an indication arrow 150.

[00249] In this embodiment, the control terminal of transistor Q₈ is connected to a reference terminal which applies reference voltage V _en through transistor Ri, and the drain terminal of transistor Q₈ is connected to the reference terminal which applies reference voltage VRen . In this way, the control terminal of transistor Q₇ is connected to the drain terminal of transistor Q₈ through resistor Ri and the reference terminal which applies reference voltage V ^n - In some embodiments, resistor R₄ is connected between the drain of transistor Q₈ and reference terminal which applies reference voltage VR_en, as indicated by an indication arrow 151. In this way, the control terminal of transistor Q₇ is connected to the drain terminal of transistor Q₈ through resistors Rj and R₄ and the reference terminal which applies reference voltage VR_en ·

[00250] In this embodiment, light emitting apparatus lOOg includes light emitting sub- circuit 131 connected to the drain of transistor Q₇ and the reference terminal which applies reference voltage V_Ren . In this embodiment, light emitting apparatus lOOg includes diode string D_A, wherein diode string D_A includes diodes D_Ai, DA2, DA3,.■ -DAN. Diode string D_A is discussed in more detail above. [00251] In this embodiment, light emitting apparatus lOOg includes light emitting sub- circuit 132 connected to the source of transistor Q₈ and the first output of controller circuit 1 10 (not shown) that provides digital control signal Scontroii - ^m this embodiment, light emitting apparatus lOOg includes diode string DB, wherein diode string DB includes diodes DBI, DB2, DB3, . . .DBN- Diode string DB is discussed in more detail above.

[00252] FIG. 8b is a circuit diagram of one embodiment of a light emitting apparatus lOOh. In this embodiment, light emitting apparatus lOOh includes transistors Q₇ and Q₈, which operate as switches, as will be discussed in more detail below. Transistors Q₇ and Q₈ can be of many different types. In this embodiment, transistors Q₇ and Q₈ are embodied as MOSFETs.

[00253] In this embodiment, the source of transistor Q₇ is connected to the first output of controller circuit 1 10 (not shown) so it receives digital control signal Scontroii, an the control terminal of transistor Q₈ is connected to the first output of controller circuit 1 10 (not shown) through resistor R₂ so it receives digital control signal Scontroii - In some embodiments, resistor R₃ is connected between the source of transistor Q₇ and the first output of controller circuit 1 10 that provides digital control signal Scontroii , as indicated by an indication arrow 150.

[00254] In this embodiment, the control terminal of transistor Q₈ is connected to a reference terminal which applies reference voltage VR_en through transistor R_{l s} and the drain terminal of transistor Q₈ is connected to the reference terminal which applies reference voltage VRen - In this way, the control terminal of transistor Q₇ is connected to the drain terminal of transistor Q₈ through resistor

and the reference terminal which applies reference voltage VR_en - In some embodiments, resistor R4 is connected between the drain of transistor Q₈ and reference terminal which applies reference voltage V _en , as indicated by an indication arrow 151. In this way, the control terminal of transistor Q₇ is connected to the drain terminal of transistor Q₈ through resistors Ri and R4 and the reference terminal which applies reference voltage V_Ren .

[00255] In this embodiment, light emitting apparatus lOOh includes light emitting sub- circuit 131 connected to the drain of transistor Q₇ and the reference terminal which applies reference voltage VR_en · In this embodiment, light emitting apparatus 1 OOh includes diode string DA, wherein diode string D_A includes diodes DAI, DA2, DA3, - DAN- Diode string D_A is discussed in more detail above. [00256] In this embodiment, light emitting apparatus lOOh includes light emitting sub- circuit 132 connected to the source of transistor Qg and the first output of controller circuit 1 10 (not shown) that provides digital control signal Scontroii - In this embodiment, light emitting apparatus lOOh includes diode string DB, wherein diode string DB includes diodes DBI , DB₂, DB3, . . .DBN- Diode string DB is discussed in more detail above.

[00257] Fig. 8c depicts a light emitting apparatus lOOh that includes a light emitting sub- circuit having an integrated circuit for the DC to DC conversion and current control. The integrated circuit depicted in Fig. 8c substitutes for various transistors and/or MOSFETs depicted in e.g. Fig. 4a that control maximum current that may be supplied and provide a DC voltage that matches load and/or accommodates voltage variation of electrical wires or other supply rails, especially at the end of long runs.

[00258] FIG. 9 is a circuit diagram of one embodiment of a load circuit 130g. In this embodiment, load circuit 130g includes light emitting sub-circuits 131 and 132 connected in reverse parallel, as discussed in more detail above with FIG. 4b. Load circuit 130g is driven by drive signal Sorive, which is discussed in more detail above.

[00259] In this embodiment, diode string DA includes diodes D_Ai, DA₂, DA3,. - DAN connected in series with a diode DCOMI, wherein DCOMI is a different type of diode than the diodes of diode string DA. In this embodiment, diode DCOMI provides a different spectrum of light than the diodes of diode string D_A. In one embodiment, diode DCOMI provides a spectrum of light at a higher frequency than the diodes of diode string D_A. For example, in one embodiment, diode string provides a visible spectrum of light and diode DCOMI provides an ultraviolet spectrum of light. In another embodiment, diode DCOMI provides a spectrum of light at a lower frequency than the diodes of diode string DA- For example, in one embodiment, diode string provides a visible spectrum of light and diode DCOMI provides an infrared spectrum of light. In general, diode strings DA and DB provide visible light for illumination and diodes DCOMI and DCOM2 provide light for communication. For example, diodes DCOMI and DCOM2 can provide light pulses for communicating with an electronic device, such as a television. It should be noted that the visible light provided by diode strings D_A and DB can illuminate the electronic device. Examples of drive signal Sohve will be discussed in more detail presently. Light pulses are discussed in more detail above, such as with FIGS. 2h, 2i and 2j. [00260] FIG. 10a is a graph 159a of an example of a multi-level DC signal SDC₁₀, wherein graph 159a corresponds to voltage verses time. In this example, multi-level DC signal Socio is a positive unipolar digital signal and can be periodic and non-periodic. DC signal Socio is a multi-level signal because it can have more than one non-zero voltage value. For example, in this embodiment, multi -level DC signal SDCIO has a value of VREF₂ between times ti and t₂ and multi-level DC signal Socio has a value of VREFI between times t₂ and t₃. Hence, multi-level DC signal Socio has magnitudes V_Mag which varies about positive reference voltages VREFI and VREF2, wherein VREFI and VREF₂ have positive voltage values. Reference voltages VREFI and V EF2 can have many different voltage values. In one embodiment, VREFI and V EF₂ are 12 volts and 24 volts, respectively. In another embodiment, VREFI and VREF2 are 3 volts and 24 volts, respectively. Multi-level DC signal SDCI2 has a value of zero volts between times t₃ and t4, and Multi-level DC signal SDCI2 has a value of zero volts between times t₅ and t .

[00261] In some embodiments, the value of VREFI and V EF2 depends on the number of diodes included in a diode string that is driven by multi-level DC signal Socio- As the number of diodes increases and decreases, the positive value of VREFI and VREF2 increase and decreases, respectively.

[00262] FIG. 10b is a graph 159b of an example of a multi-level DC signal S_Dcn, wherein graph 159b corresponds to voltage verses time. In this example, multi-level DC signal Soci i is a negative unipolar digital signal and can be periodic and non-periodic. DC signal Socn is a multi-level signal because it can have more than one non-zero voltage value. For example, in this embodiment, multi-level DC signal Socn has a value of -VREF2 between times ti and t2 and multi-level DC signal Socn has a value of -VREFI between times t₂ and t₃. Hence, multi-level DC signal SDCI I has magnitudes V ag which varies about negative reference voltages -VREFI and -VRE_F2, wherein -VREFI and -VREF2 have negative voltage values. Reference voltages -VREFI and -VREF2 can have many different voltage values. In one embodiment, -VRE_F1 and -VREF2 are -12 volts and -24 volts, respectively. In another embodiment, -VREFI and -VREF2 are -3 volts and -24 volts, respectively. Multi-level DC signal Soci2 has a value of zero volts between times t₃ and U, and Multi-level DC signal Soci2 has a value of zero volts between times t₅ and -

[00263] In some embodiments, the value of -VREFI and -VRE_F2 depends on the number of diodes included in a diode string that is driven by multi-level DC signal Socn- As the number of diodes increases and decreases, the negative value of -VREFI and -VREF2 increase and decreases, respectively.

[00264] FIG. 10c is a graph 159c of an example of a multi-level DC signal SDCI2, wherein graph 159c corresponds to voltage verses time. In this example, multi-level DC signal Soci2 is a bipolar digital signal and can be periodic and non-periodic. DC signal Soci2 is a multi-level signal because it can have more than one non-zero voltage value. For example, in this embodiment, multi-level DC signal Spcn has a value of VREF2 between times ti and t₂ and multi-level DC signal SDCI2 has a value of VREFI between times t₂ and t₃. Multi-level DC signal SDCI2 has a value of -VREFI between times t₃ and and multi-level DC signal SDCI2 has a value of VREFI between times U and t₅. Multi-level DC signal Soci2 has a value of -VREF2 between times t$ and t₇ and multi-level DC signal SDCI2 has a value of -VREFI between times t₇ and tg. Multi-level DC signal Soci2 has a value of zero volts between times t₅ and t6.

[00265] Hence, multi-level DC signal Soci2 has magnitudes VMag which varies about positive reference voltages VREFI and V EF2, wherein VREFI and VREF2 have positive voltage values. Further, multi-level DC signal Soci2 has magnitudes V ag which varies about negative reference voltages -VREFI and -VREF2, wherein -VREFI and -VREF2 have negative voltage values.

[00266] Reference voltages VREFI and VREF2 can have many different voltage values. In one embodiment, VREFI and V EF₂ are 12 volts and 24 volts, respectively. In another embodiment, VREFI and VRE_F2 are 3 volts and 12 volts, respectively.

[00267] Reference voltages -VREFI and -VREF2 can have many different voltage values. In one embodiment, -VREFI and -VREF2 are -12 volts and -24 volts, respectively. In another embodiment, -VREFI and -VREF2 are -3 volts and -24 volts, respectively. In another embodiment, -VREFI and -VREF₂ are -3 volts and -12 volts, respectively.

[00268] FIG. lOd is a graph 159d of an example of a multi-level DC signal Socn, wherein graph 159d corresponds to voltage verses time. In this example, multi-level DC signal SDCB is a bipolar digital signal and can be periodic and non-periodic. DC signal Socn is a multi-level signal because it can have more than one non-zero voltage value. For example, in this embodiment, multi-level DC signal SDCB has a value of V EF4 between times ti and t2 and multi-level DC signal SDCI3 has a value of VREFI between times t₂ and t₃. Multi-level DC signal SDCB has a value of VREF3 between times t4 and t₅. Multi-level DC signal SDCB has a value of -VREF2 between times t6 and t₇ and multi-level DC signal SDCI₃ has a value of -VREFI between times t₇ and t₈. Multi-level DC signal SDCB has a value of zero volts between times t₃ and , and Multi-level DC signal SDCI3 has a value of zero volts between times t and t_$.

[00269] Hence, multi-level DC signal SQCU has magnitudes VMag which varies about positive reference voltages VRE_F1, VREF2, VRE_F3 and VREF₄, wherein VREFI , VRE_F2, REF3 and REF4 have positive voltage values and V EF4 is more positive than VREF3, REF3 is more positive than VREF2 and VREF2 is more positive than VREFI -

[00270J Further, multi-level DC signal Socn has magnitudes Vi jag which varies about negative reference voltages -VREFI, -VRE_F2, -V_REF3 and -VREF_4> wherein -VREFI, -VREF2, - VREF3 and -VREF4 have negative voltage values and -VREF4 is more negative than VREF3, VREF3 is more negative than VREF2 and VREF₂ is more negative than VREFI - [00271] Reference voltages VREFI, VRE_F2, VREF3 and VRE_F4 can have many different voltage values. In one embodiment, VREFI, VREF2, VRE_F3 and VREF4 are 3 volts, 6 volts, 12 volts and 24 volts, respectively.

[00272] Reference voltages -VREFI, -VRE_F2, -VREFS and -VREF4 can have many different voltage values. In one embodiment, -VREFI , -VREF2, -VREF3 and -VREF4 are -3 volts, -6 volts, - 12 volts and -24 volts, respectively.

[00273] In some embodiments, the number of reference voltage values depends on the number of light emitting sub-circuits. Further, as the number of light emitting sub-circuits increases and decreases, the number of reference voltage values increase and decreases, respectively. As the number of positive polarity light emitting sub-circuits increases and decreases, the number of positive reference voltage values increase and decreases, respectively. Further, as the number of negative polarity light emitting sub-circuits increases and decreases, the number of negative reference voltage values increase and decreases, respectively.

[00274] FIG. 11a is a graph 147 of an example of a positive unipolar digital signal SDC7 having a fifty percent (50%) duty cycle, wherein graph 147 corresponds to voltage verses time. More information regarding positive unipolar digital signal SDC7 is provided above with FIG. 2e. In this example, positive unipolar digital signal SDC7 is a periodic non- sinusoidal signal having period T₂. Signal SDC7 is a positive unipolar signal because it has positive voltage values for period T₂. It should be noted that the deactive edge of signal SDC7 has a zero voltage value, which is a positive voltage value, as mentioned above. Signal SDC7 is not a bipolar signal because signal SDC7 has positive voltage values for period T₂.

[00275] Positive unipolar digital signal SDC7 has a fifty percent (50%) duty cycle because the length of time of its active edge is the same as the length of time of its deactive edge. In this particular example, the active edge of signal SDC₇ extends between times tj and t₂, wherein time t₂ is greater than time t]. The portion of signal SDC7 with the active edge between times and t₂ is denoted as signal SDC7₃- Further, the deactive edge of signal SDC7 extends between times t₂ and t₃, wherein time t₃ is greater than time t₂. The active edge of signal SDC7 extends between times t₃ and t4, wherein time is greater than time t₃. The portion of signal SDC7 with the active edge between times t₃ and is denoted as signal Soc _b- Further, the deactive edge of signal SDC7 extends between times U and t₅, wherein time t₅ is greater than time U- ■ The active edge of signal SDC7 extends between times t₅ and t6, wherein time ¼ is greater than time t₅. The portion of signal SDC7 with the active edge between times t₅ and t6 is denoted as signal SDC7_C- Further, the deactive edge of signal SDC7 extends between times te and t₇, wherein time t₇ is greater than time

[00276] Positive unipolar digital signal SDC7 has a fifty percent (50%) duty cycle because the time difference between times t₂ and is the same as the time difference between times t₃ and t₂. In this way, positive unipolar digital signal SDC7 has a fifty percent (50%) duty cycle because the length of time of its active edge is the same as the length of time of its deactive edge. It should be noted that, in this example, time ti corresponds to the time of the rising edge of signal SDC7, time t₂ corresponds to the time of the falling edge of signal SDC7 and the difference between times t_\ and t₃ corresponds to period T₂. It should be noted that, in this example, Positive unipolar digital signal SDC7 has a fifty percent (50%) duty cycle between times t₃ and t₅ and between times t₅ and t₇.

[00277] FIG. lib is a graph 147a of an example of a digital signal S_Digitaii shown with positive unipolar digital signal Soc7a (in phantom) of FIG. 11a, wherein graph 147a corresponds to voltage verses time. It should be noted that digital signal Soigitaii can correspond to drive signal S_Drive of FIG. 10. In this example, the digital signal S_Di_gitaii has [00278] a zero value ("0") between times and ti_a,

[00279] a one value ("1") between times tia and tib,

[00280] a zero value ("0") between times tib and t_lc,

[00281] a one value ("1") between times tj_c and tia, [00282] a zero value ("0") between times tid and t_]e,

[00283] a one value ("1") between times t_le and tif,

[00284] a zero value ("0") between times tif and ti_g,

[00285] a zero value ("0") between times t_lg and tih,

[00286] a zero value ("0") between times tih and t]j,

[00287] a one value ("1") between times tn and tij,

[00288] a zero value ("0") between times ti_j and tj_k, and

[00289] a zero value ("0") between times tik and t₂.

[00290] It should be noted that (Fig 1 lb?)

[00291] time tia is greater than time t),

[00292] time ti_b is greater than time t_la,

[00293] time t_lc is greater than time ti_b,

[00294] time ti_d is greater than time ti_c,

[00295] time ti_e is greater than time tid,

[00296] time tjf is greater than time ti_e,

[00297] time t_lg is greater than time tif,

[00298] time tn, is greater than time ti_g,

[00299] time , is greater than time tih,

[00300] time ti_j is greater than time tu,

[00301] time t)k is greater than time tij and

[00302] time t₂ is greater than time tik.

[00303] Digital signal S_Di_gitaii has a duty cycle less than fifty percent (50%) because the length of time of its active edge is the less than the length of time of its deactive edge. In this particular example, the active edge of digital signal Soigitaii extends between times t_{l a} and ti_b, times t_{] c} and ti_d, times t_{] e} and tjf and times tjj and tij.

[00304] FIG. 11c is a graph 147b of an example of a digital signal Soigitan shown with positive unipolar digital signal S_Dc7b (in phantom) of FIG. 11a, wherein graph 147c corresponds to voltage verses time. It should be noted that digital signal SoigUan can correspond to drive signal Sorive of FIG. 10. In this example, the digital signal Soigitan has [00305] a zero value ("0") between times t₃ and t_3a,

[00306] a one value ("1") between times t_3a and t_3b,

[00307] a zero value ("0") between times ι¾ and t_3c, [00308] a zero value ("0") between times t_3c and t₃d,

[00309] a one value ("1") between times t_3d and t_3e,

[00310] a one value ("1") between times t_3e and t_3f,

[00311] a zero value ("0") between times t_3f and t_3g,

[00312] a zero value ("0") between times t_3g and t_3h,

[00313] a zero value ("0") between times t_3h and t₃j,

[00314] a one value (" 1 ") between times t₃, and t¾,

[00315] a zero value ("0") between times t¾ and and

[00316] a zero value ("0") between times t_3k and t4.

[00317] It should be noted that

[00318] time t_3a is greater than time t₃,

[00319] time t₃b is greater than time t_3a,

[00320] time t_3c is greater than time t₃b,

[00321] time t_3d is greater than time t_3c,

[00322] time t_3e is greater than time t_3ij,

[00323] time t_3f is greater than time t_3e,

[00324] time t_3g is greater than time t_3f,

[00325] time t_3h is greater than time t_3g,

[00326] time t₃i is greater than time t_3h,

[00327] time t_3j is greater than time t₃j,

[00328] time t_3k is greater than time t¾ and

[00329] time t4 is greater than time t_3k.

[00330] Digital signal S_Di_gkai2 has a duty cycle less than fifty percent (50%) because the length of time of its active edge is the less than the length of time of its deactive edge. In this particular example, the active edge of digital signal Soigi_taii extends between times t_3a and t_3b, times t₃d and t_3e, times t_3e and t_3f and times t₃j and t_3j. It should be noted that the duty cycles of digital signal Soigitaii and Soi_gitai2 are the same.

[00331] FIG. lid is a graph 147c of an example of a digital signal Soigi_taU shown with positive unipolar digital signal SDC7_C (in phantom) of FIG. 11a, wherein graph 147c corresponds to voltage verses time. It should be noted that digital signal SoigitaB can correspond to drive signal Sorive of FIG. 10. In this example, the digital signal Soigitatt has [00332] a zero value ("0") between times t₅ and t_5a, [00333] a zero value ("0") between times t_5a and t_5b,

[00334] a zero value ("0") between times t₅b and t_5c,

[00335] a one value ("1") between times t_5c and t_Sd,

[00336] a zero value ("0") between times t₅₍j and t_5e,

[00337] a one value (" 1 ") between times t_5e and t₅f,

[00338] a zero value ("0") between times t₅f and t_5g,

[00339] a one value (" 1 ") between times t_5g and t₅h,

[00340] a zero value ("0") between times t₅h and t₅j,

[00341] a one value ("1") between times t₅i and t₅j,

[00342] a zero value ("0") between times t₅j and t5k, and

[00343] a zero value ("0") between times t₅k and t6.

[00344] It should be noted that

[00345] time t_5a is greater than time t₅,

[00346] time t₅b is greater than time t_5a,

[00347] time t_5c is greater than time t_5b,

[00348] time t_5<j is greater than time t_5c,

[00349] time t_5e is greater than time t₅d,

[00350] time t_5f is greater than time t_5e,

[00351] time t_5g is greater than time t_5f,

[00352] time t_5h is greater than time t_5g,

[00353] time t₅i is greater than time t_5h,

[00354] time t_5j is greater than time t₅j,

[00355] time t_5k is greater than time t¾ and

[00356] time t6 is greater than time t_5k.

[00357] Digital signal S_Di_gitai3 has a duty cycle less than fifty percent (50%) because the length of time of its active edge is the less than the length of time of its deactive edge. In this particular example, the active edge of digital signal SDigitaU extends between times t_5c and t_5d, times t_5e and t_5f, times t_5g and t_5h and times t_5i and t₅j. Digital signal S_Di_gitai3 has a duty cycle less than fifty percent (50%) because the length of time of its active edge is the less than the length of time of its deactive edge. It should be noted that the duty cycles of digital signal Soigitaii, Soigitai2 and Soi_gitai3 are the same. [00358] FIG. 12a is a graph 148 of an example of a bipolar digital signal SDCS, wherein graph 148 corresponds to voltage verses time. More information regarding bipolar digital signals is provided above, such as with FIG. 2d. It should be noted that bipolar digital signal Socscan correspond to drive signal Sorive of FIG. 10. In this example, bipolar digital signal SDCS is a periodic non-sinusoidal signal having period Tj, and has a magnitude which varies about a zero voltage value. Bipolar digital signal SDCS has positive and negative active edges, wherein the positive and negative active edges correspond to positive and negative voltage values, respectively, as will be discussed in more detail presently.

[00359] In this particular example, a first positive active edge of signal SDCS extends between times t] and t₂, wherein time t₂ is greater than time tj. The portion of signal SDCS with the first positive active edge between times ti and t₂ is denoted as signal Socsa- Further, a first negative active edge of signal SDCS extends between times t₂ and t₃, wherein time t₃ is greater than time t₂. The portion of signal SDCS with the first negative active edge between times t₂ and t₃ is denoted as signal Socs_b- [00360] In this particular example, the difference between times tj and t₂ is the same as the difference between times t₂ and t₃. In this way, the length of time of the first positive active edge of signal SDCS is the same as the length of time of the first negative active edge of signal SDCS-

[00361] A second positive active edge of signal SDCS extends between times t₃ and Ϊ4, wherein time Ϊ4 is greater than time t₃. The portion of signal SDCS with the second positive active edge between times t₃ and U is denoted as signal SDCS_C- Further, a second negative active edge of signal SDCS extends between times and t₅, wherein time t₅ is greater than time t4. The portion of signal SDCS with the second negative active edge between times t4 and t₅ is denoted as signal Socsd- [00362] In this particular example, the difference between times t₃ and is the same as the difference between times U and t₅. In this way, the length of time of the second positive active edge of signal SDCS is the same as the length of time of the second negative active edge of signal S_Dcs-

[00363] A third positive active edge of signal SDCS extends between times t₅ and wherein time t6 is greater than time t₅. The portion of signal SDCS with the third positive active edge between times t₅ and t6 is denoted as signal Socs_e- Further, a third negative active edge of signal SDCS extends between times and t₇, wherein time t₇ is greater than time t$. The portion of signal Socg with the third negative active edge between times t^ and t₇ is denoted as signal Socs_f-

[00364] In this particular example, the difference between times t₅ and t$ is the same as the difference between times and t₇. In this way, the length of time of the third positive active edge of signal SDCS is the same as the length of time of the third negative active edge of signal S_Dcs-

[00365] FIG. 12b is a graph 148a of an example of a digital signal Soi_gi_taw shown with signal Socsa (in phantom) and Soc8b (in phantom) of FIG. 12a, wherein graph 148a corresponds to voltage verses time. It should be noted that digital signal Soi_gi_taw can correspond to drive signal Sorive of FIG. 10. Digital signal S Digital can include a positive one value ("+1"), a negative one value ("-1") and/or a zero value ("0"). A positive one value corresponds to a voltage value that is greater than zero volts and a negative one value corresponds to a voltage value that is less than zero volts.

[00366] In this example, signal Soigitai4 has

[00367] a zero value ("0") between times ti and tj_a,

[00368] a zero value ("0") between times t_la and tib,

[00369] a zero value ("0") between times tib and t_lc,

[00370] a positive one value ("+1") between times ti_c and ti_d,

[00371] a zero value ("0") between times tid and ti_e,

[00372] a positive one value ("+1") between times tj_e and tif,

[00373] a zero value ("0") between times tif and t_lg, and

[00374] a zero value ("0") between times t_lg and t₂.

[00375] As mentioned above,

[00376] time tia is greater than time ti,

[00377] time tjb is greater than time ti_a,

[00378] time tic is greater than time tib,

[00379] time tia is greater than time ti_c,

[00380] time tie is greater than time tid,

[00381] time tif is greater than time ti_e,

[00382] time tig is greater than time tif and

[00383] time t₂ is greater than time ti_g. [00384] Between times t] and t₂, signal Soigitaw has a duty cycle less than fifty percent (50%) because the length of time of its active edge is the less than the length of time of its deactive edge. In this particular example, the active edge of signal SoigitaM between times t] and t₂ extends between times ti_c and ti_d and times ti_e and ti_f, wherein the active edges correspond to a positive one value ("+1 ").

[00385] In this example, signal Soigitaw has

[00386] a zero value ("0") between times t₂ and t_2a,

[00387] a negative one value ("-1") between times t_2a and t_¾,

[00388] a negative one value between times t_¾ and t_2c,

[00389] a zero value ("0") between times t_2c and t₂₍j,

[00390] a zero value ("0") between times t₂d and t_2e,

[00391] a negative one value between times t_2e and t₂f,

[00392] a zero value ("0") between times t_2f and t_2g, and

[00393] a zero value ("0") between times t_2g and t₃.

[00394] As mentioned above,

[00395] time t_2a is greater than time t₂,

[00396] time t₂b is greater than time t_2a,

[00397] time t_2c is greater than time t₂b,

[00398] time t_2d is greater than time t_2c,

[00399] time t_2e is greater than time t₂d,

[00400] time t_2f is greater than time t_2e,

[00401] time t_2g is greater than time t_2f and

[00402] time t₃ is greater than time t_2g.

[00403] Between times t₂ and t₃, signal Soigi_taw has a duty cycle less than fifty percent (50%) because the length of time of its negative active edge is the less than the length of time of its deactive edge. In this particular example, the negative active edge of signal SDigitai4 between times t₂ and t₃ extends between times t_2a and t₂b, times t₂b and t_2c and times t_2e and t₂f, wherein the negative active edges correspond to a negative one value ("-1").

[00404] FIG. 12c is a graph 148b of an example of a digital signal Soigkais shown with signal S_Dc8c (in phantom) and Socsd (in phantom) of FIG. 12a, wherein graph 148b corresponds to voltage verses time. It should be noted that digital signal Soiguais can correspond to drive signal Strive of FIG. 10. Digital signal Soigitais can include a positive one value ("+1"), a negative one value ("-1") and/or a zero value ("0"). A positive one value corresponds to a voltage value that is greater than zero volts and a negative one value corresponds to a voltage value that is less than zero volts.

[00405] In this example, signal Soigitais has

[00406] a zero value ("0") between times t₃ and t_3a,

[00407] a positive one value ("+1") between times t_3a and t_3b,

[00408] a positive one value ("+1") between times t_3b and t_3c,

[00409] a zero value ("0") between times t_3c and t₃a,

[00410] a zero value ("0") between times t₃d and t_3e,

[00411] a positive one value ") between times t_3e and t_3f,

[00412] a zero value ("0") between times t₃f and t_3g, and

[00413J a zero value ("0") between times t_3g and -

[00414] As mentioned above,

[00415] time t_3a is greater than time t₃,

[00416] time t₃b is greater than time t_3a,

[00417] time t_3c is greater than time t_3b,

[00418] time t₃d is greater than time t_3c,

[00419] time t_3e is greater than time t₃₍j,

[00420] time t_3f is greater than time t_3e,

[00421] time t_3g is greater than time t₃f and

[00422] time is greater than time t_3g.

[004231 Between times t₃ and t4, signal Soigi_tais has a duty cycle less than fifty percent

(50%) because the length of time of its active edge is the less than the length of time of its deactive edge. In this particular example, the active edge of signal S_Di_gitai5 between times t₃ and t4 extends between times t_3a and t_3b, times t₃b and t_3c and times t_3e and t₃f.

[00424] In this example, signal S_Di_gitai5 has

[00425] a zero value ("0") between times U and tta,

[00426] a negative one value ("-1 ") between times U and t4b,

[00427] a zero value ("0") between times t4b and t4_C,

[00428] a zero value ("0") between times t _C and t4_d,

[00429] a zero value ("0") between times d and Ue,

[00430] a negative one value ("-1 ") between times t4e and Uf, [00431] a zero value ("0") between times t4f and t4_g, and

[00432] a zero value ("0") between times g and t₅.

[00433] As mentioned above,

[00434] time t4_a is greater than time U,

[00435] time t4b is greater than time t4_a,

[00436] time t4_C is greater than time tb,

[00437] time t4d is greater than time t4_C,

[00438] time t4e is greater than time t4<j,

[00439] time Ui is greater than time t4_e,

[00440] time t4_g is greater than time t4f and

[00441] time t₅ is greater than time t_g.

[00442] Between times t4 and t₅, signal Soigi_tais has a duty cycle less than fifty percent

(50%) because the length of time of its negative active edge is the less than the length of time of its deactive edge. In this particular example, the negative active edge of signal Soigi_tais between times U and t₅ extends between times t4_a and t4 and times t4_e and f, wherein the negative active edges correspond to a negative one value ("-1").

[00443] It should be noted that the duty cycle of signal Soigi_tais between times t₃ and is different than the duty cycle of signal Soigi_tais between times and t₅. In this example, the duty cycle of signal Soigi_tais between times t₃ and is greater than the duty cycle of signal Soigi_tais between times t4 and t₅. In other examples, the duty cycle of signal Soigitais between times t₃ and is less than or equal to the duty cycle of signal Soigi_tais between times t4 and t₅. In this way, the duty cycle of signal Soigi_tais between times t₃ and t4 and the duty cycle of signal Soigi_tais between times and t₅ are adjustable.

[00444] FIG. 12d is a graph 148c of an example of a digital signal Soi_gitai6 shown with signal Socse (in phantom) and Socsf (in phantom) of FIG. 12a, wherein graph 148c corresponds to voltage verses time. It should be noted that digital signal Soi_gitai6 can correspond to drive signal Sorive of FIG. 10. Digital signal Soi_gitai6 can include a positive one value ("+1"), a negative one value ("-1") and/or a zero value ("0"). A positive one value corresponds to a voltage value that is greater than zero volts and a negative one value corresponds to a voltage value that is less than zero volts.

[00445] In this example, signal Soi_gitai6 has

[00446] a zero value ("0") between times t₅ and t_5a, [00447] a zero value ("0") between times t_5a and t₅b,

[00448] a positive one value ("+1 ") between times t₅b and t _c,

[00449] a zero value ("0") between times t_5c and t₅₍j,

[00450] a zero value ("0") between times t_5ci and t_5e,

[00451] a positive one value ("+1 ") between times t_5e and t₅f,

[004521 a zero value ("0") between times t₅f and t_5g, and

[00453] a zero value ("0") between times t_5g and t6.

[00454] As mentioned above,

[00455] time t_5a is greater than time t₅,

[00456] time t5 is greater than time t_5a,

[00457] time t_5c is greater than time t₅b,

[00458] time t₅d is greater than time t_5c,

[00459] time t_5e is greater than time t ₍₁,

[00460] time t₅f is greater than time t₅e,

[00461] time t_5g is greater than time t₅f and

[00462] time t6 is greater than time t_5g.

[00463] Between times t₅ and , signal SDigitaie has a duty cycle less than fifty percent

(50%) because the length of time of its active edge is the less than the length of time of its deactive edge. In this particular example, the active edge of signal S_Di_gitai6 between times t₅ and t6 extends between times t₅b and t_5c and times t_5e and t₅f.

[00464] In this example, signal Soigitaie has

[00465] a zero value ("0") between times t6 and t6_a,

[00466] a zero value ("0") between times and t b,

[00467] a zero value ("0") between times t6b and t^,

[00468] a negative one value ("-1 ") between times t^_c and d,

[00469] a zero value ("0") between times t^a and t6_e,

[00470] a negative one value ("-1") between times t^ and t^f,

[00471] a zero value ("0") between times f and t6_g, and

[00472] a zero value ("0") between times t6_g and t₇.

[00473] As mentioned above,

[00474] time t6a is greater than time t$,

[00475] time t6b is greater than time t^, [00476] time t^ is greater than time t^,

[00477] time i is greater than time t^,

[00478] time t_& is greater than time t6d,

[00479] time is greater than time t$_e,

[00480] time tg_g is greater than time fa and

[00481] time t₇ is greater than time t6_g.

[00482] Between times and t₇, signal Soigitai₆ has a duty cycle less than fifty percent (50%) because the length of time of its negative active edge is the less than the length of time of its deactive edge. In this particular example, the negative active edge of signal SDi_gitai6 between times t6 and t₇ extends between times t^ and t d and times t6_e and t6f, wherein the negative active edges correspond to a negative one value ("-1").

[00483] It should be noted that the duty cycle of signal Soigitai6 between times t₅ and is the same as the duty cycle of signal Soi_gi_taie between times and t₇. In other examples, the duty cycle of signal Soi_gitai6 between times t₅ and t₆ is different from the duty cycle of signal SDi_gita!6 between times t and t₇. In other examples, the duty cycle of signal Soigitaie between times t₅ and t^ is greater than or less than the duty cycle of signal Soi_g ai6 between times t6 and t₇. In this way, the duty cycle of signal Soi_gitai6 between times t₅ and te and the duty cycle of signal SDi_gitai6 between times and t₇ are adjustable.

[00484] FIG. 13a is a graph 149a of an example of a digital signal Soi itai7 shown with signal Socsa (in phantom) and Socsb (in phantom) of FIG. 12a, wherein graph 149a corresponds to voltage verses time. It should be noted that digital signal Soigitan can correspond to drive signal Sorive of FIG. 10. Digital signal Soigitan can include a positive one value ("+1"), a negative one value ("-1") and/or a zero value ("0")· A positive one value corresponds to a voltage value that is greater than zero volts and a negative one value corresponds to a voltage value that is less than zero volts.

[00485] In this example, signal Soigitan has

[00486] a zero value ("0") between times ti and ti_a,

[00487] a positive one value ("+1") between times t_la and ti_b,

[00488] a zero value ("0") between times ti_b and t_lc,

[00489] a negative one value ("-1 ") between times tj_c and ti_d,

[00490] a zero value ("0") between times tid and ti_e,

[00491] a positive one value ("+1") between times ti_e and ti_f, [00492] a positive one value ("+1") between times t^ and ti_g, and

[00493] a zero value ("0") between times ti_g and t₂.

[00494] As mentioned above,

[00495] time t_2a is greater than time t₂,

[00496] time t_2b is greater than time t_2a,

[004971 time t_2c is greater than time t₂b,

[00498] time t₂a is greater than time t_2c,

[00499] time t_2e is greater than time t_2d,

[00500] time t_2f is greater than time t_2e,

[00501] time t_2g is greater than time t_2f and

[00502] time t₃ is greater than time t_2g.

[00503] Between times ti and t₂, signal SDi_gitai7 has a duty cycle equal to fifty percent

(50%) because the length of time of its positive and negative active edges is the same as the length of time of its deactive edge. In this particular example, the positive active edge of signal SDi_gitai7 between times ti and t₂ extends between times tj_a and tib, times tj_e and tif and times ti_f and tj_g. Further, the negative active edge of signal Soigitan between times ti and t₂ extends between times t_5c and t_5tj.

[00504] In this example, signal Soigitan has

[005051 a zero value ("0") between times t₂ and t_2a,

[00506] a negative one value ("-1 ") between times t_2a and t¾,

[00507] a negative one value ("-1") between times t_¾ and t_2c,

[00508] a zero value ("0") between times t_2c and t₂d,

[00509] a zero value ("0") between times t₂₍j and t_2e,

[00510] a negative one value ("-1") between times t _e and t₂f,

[00511] a zero value ("0") between times t_2f and t_2g, and

[00512] a zero value ("0") between times t_2g and t₃.

[00513] As mentioned above,

[00514] time t_2a is greater than time t₂,

[00515] time t_2b is greater than time t_2a,

[00516] time t_2c is greater than time t₂b,

[005171 time t_2d is greater than time t_2c,

[00518] time t_2e is greater than time t₂a, [00519] time t_2f is greater than time t_2e,

[00520] time t_2g is greater than time t_2f and

[00521] time t₃ is greater than time t_2g.

[00522] Between times t₂ and t₃, signal Soi_gi_tan has a duty cycle less than fifty percent (50%) because the length of time of its negative active edge is the less than the length of time of its deactive edge. In this particular example, the negative active edge of signal Soigitai7 between times t₂ and t₃ extends between times t_2a and t₂b, times t_¾ and t_2c and times t_2e and t₂f, wherein the negative active edges correspond to a negative one value ("-1")·

[00523] It should be noted that the duty cycle of signal Soi_gi_tan between times and t₂ is different than the duty cycle of signal Sa_ltan between times ti and t₂. In this example, the duty cycle of signal Soigitan between times and t₂ is greater than the duty cycle of signal Soigitan between times t₂ and t₃. In other examples, the duty cycle of signal S_Di_gitai7 between times and t₂ is less than or equal to the duty cycle of signal Soi_gi_tan between times t₂ and t₃. In this way, the duty cycle of signal S_Di_gitai7 between times and t₂ and the duty cycle of signal Soigitan between times t₂ and t₃ are adjustable.

[00524] FIG. 13b is a graph 149b of an example of a digital signal Soigi_tais shown with signal Socsc (in phantom) and Socsd (in phantom) of FIG. 12a, wherein graph 149b corresponds to voltage verses time. It should be noted that digital signal Soi_gitais can correspond to drive signal So_rive of FIG. 10. Digital signal Soigitais can include a positive one value ("+1"), a negative one value ("-1") and/or a zero value ("0"). A positive one value corresponds to a voltage value that is greater than zero volts and a negative one value corresponds to a voltage value that is less than zero volts.

[00525] In this example, signal Soigitais has

[00526] a zero value ("0") between times t₃ and t_3a,

[00527] a positive one value ("+1") between times t_3a and t₃b,

[00528] a positive one value ("+1") between times t₃b and t_3c,

[00529] a zero value ("0") between times t_3c and t₃d,

[00530] a zero value ("0") between times t₃d and t_3e,

[00531] a positive one value ("+1") between times t_3e and t_3f,

[00532] a zero value ("0") between times t₃f and t_3g, and

[00533] a zero value ("0") between times t_3g and Ϊ4.

[00534] As mentioned above, [00535] time t_3a is greater than time t₃,

[00536J time t_3b is greater than time t_3a,

[00537] time t_3c is greater than time t_3b,

[00538] time t₃₍j is greater than time t_3c,

[00539] time t3_e is greater than time t_3d,

[00540] time t_3f is greater than time t_3e,

[00541] time t_3g is greater than time t_3f and

[00542] time U is greater than time t_3g.

[00543] Between times t₃ and t4, signal S_Di_gitai8 has a duty cycle less than fifty percent (50%) because the length of time of its active edge is the less than the length of time of its deactive edge. In this particular example, the active edge of signal Soigitais between times t₃ and t4 extends between times t_3a and t_3b, times t₃b and t_3c and times t_3e and t₃f.

[00544] In this example, signal Soigitais has

[00545] a zero value ("0") between times t4 and t4_a,

[00546] a negative one value ("- 1 ") between times U_a and t4_b,

[00547] a zero value ("0") between times t4b and t4_C,

[00548] a zero value ("0") between times t4_C and d,

[00549] a zero value ("0") between times t4d and Ue,

[00550] a negative one value ("-1 ") between times t4_e and t4f,

[00551] a zero value ("0") between times t4f and t4_g, and

[00552J a zero value ("0") between times t4_g and t₅.

[00553] As mentioned above,

[00554] time Ua is greater than time t4,

[00555] time Ub is greater than time t4_a,

[00556] time Uc is greater than time t4b,

[00557] time Ud is greater than time t4_C,

[00558] time t4_e is greater than time Ud,

[00559] time t4f is greater than time t4_e,

[00560] time t4_g is greater than time Uf and

[00561] time t₅ is greater than time t4_g.

[00562] Between times t4 and t₅, signal S_Di_giiai8 has a duty cycle less than fifty percent

(50%) because the length of time of its negative active edge is the less than the length of time of its deactive edge. In this particular example, the negative active edge of signal Soigitais between times t4 and t₅ extends between times Ua and t4b and times t4_e and t4f, wherein the negative active edges correspond to a negative one value ("-1").

[00563] It should be noted that the duty cycle of signal Soi_gi_tais between times t₃ and t4 is different than the duty cycle of signal Soi_gi_tais between times t4 and t₅. In this example, the duty cycle of signal Soigitais between times t₃ and is greater than the duty cycle of signal Soigitais between times t4 and t₅. In other examples, the duty cycle of signal Soigitais between times t₃ and I4 is less than or equal to the duty cycle of signal Soigitais between times t4 and t₅. In this way, the duty cycle of signal Soi_gi_tais between times t₃ and t4 and the duty cycle of signal Soigit_ais between times t4 and t₅ are adjustable.

[00564] FIG. 13c is a graph 149c of an example of a digital signal Soi_gitai9 shown with signal Socs_e (in phantom) and Socs_f (in phantom) of FIG. 12a, wherein graph 149c corresponds to voltage verses time. It should be noted that digital signal Soi_gitai9 can correspond to drive signal So_nve of FIG. 10. Digital signal Soigitai9 can include a positive one value ("+1"), a negative one value ("-1") and/or a zero value ("0"). A positive one value corresponds to a voltage value that is greater than zero volts and a negative one value corresponds to a voltage value that is less than zero volts.

[00565] In this example, signal Soi_gitai9 has

[00566] a zero value ("0") between times t₅ and t_5a,

[00567] a positive one value ("+1") between times t_5a and t₅b,

[00568] a negative one value ("-1") between times t₅b and t_5c,

[00569] a zero value ("0") between times t_5c and t_5c),

[00570] a positive one value ("+1") between times t₅₍j and t_5e,

[00571] a positive one value between times t _e and t_5f,

[00572] a zero value ("0") between times t_5f and t_5g, and

[00573] a zero value ("0") between times t_5g and -

[00574] As mentioned above,

[00575] time t_5a is greater than time t₅,

[00576] time t₅b is greater than time t_5a,

[00577] time t_5c is greater than time t₅b,

[00578] time t_5d is greater than time t_5c,

[005791 time t_5e is greater than time t₅₍j, [00580] time t₅f is greater than time t_5e,

[00581] time t_5g is greater than time t₅f and

[00582] time t^ is greater than time t_5g.

[00583] Between times t₅ and t6, signal SDi_gitai9 has a duty cycle equal to fifty percent (50%) because the length of time of its positive and negative active edges is the same as the length of time of its deactive edge. In this particular example, the positive active edge of signal Soi_gitai9 between times t₅ and extends between times t_5a and t₅b, times t₅d and t_5e and times t_5e and t f. Further, the negative active edge of signal Soigitai9 between times t₅ and t$ extends between times t₅b and t_5c.

[00584] In this example, signal SDi_gitai9 has

[00585] a negative one value ("-1 ") between times t6 and t^,

[00586] a negative one value between times t$_a and t6b,

[00587] a zero value ("0") between times teb and t^,

[00588] a positive one value ("+1 ") between times t6_C and t6d,

[00589] a zero value ("0") between times t6d and tge,

[00590] a zero value ("0") between times _e and t6f,

[00591] a positive one value ("+1") between times and t6_g, and

[00592] a zero value ("0") between times t^ and t₇.

[00593] As mentioned above,

[00594] time t^a is greater than time

[00595] time t6b is greater than time t^,

[00596] time tec is greater than time t^,

[00597] time t6d is greater than time t6_C,

[00598] time t6e is greater than time t$d,

[00599] time t$f is greater than time t6_e,

[00600] time t6_g is greater than time ½ and

[00601] time t₇ is greater than time t6_g.

[00602] Between times t and t₇, signal SDi_gitai9 has a duty cycle equal to fifty percent

(50%) because the length of time of its positive and negative active edges is the same as the length of time of its deactive edge. In this particular example, the positive active edge of signal Soi_gitai9 between times t6 and t₇ extends between times t^ and t^ and times t^e and wherein the positive active edges correspond to a positive one value ("+1"). Further, the negative active edge of signal Soi_gitai9 between times ¼ and t₇ extends between times ¼ and tfo and times t^ and b, wherein the negative active edges correspond to a negative one value ("-1").

[00603] It should be noted that the duty cycle of signal Soigitai9 between times t₅ and ¼ is the same as the duty cycle of signal SDi_gitai between times ¼ and t₇. In other examples, the duty cycle of signal Soi_gitai9 between times t₅ and t6 is different from the duty cycle of signal SDigitai9 between times t6 and t₇. In other examples, the duty cycle of signal SoigitaW between times t₅ and ¾ is greater than or less than the duty cycle of signal S_Di_gitai6 between times ¼ and t₇. In this way, the duty cycle of signal SDi_gitai9 between times t₅ and ¼ and the duty cycle of signal SDi_gitai9 between times t$ and t are adjustable.

[00604] The embodiments of the invention described herein are exemplary and numerous modifications, variations and rearrangements can be readily envisioned to achieve substantially equivalent results, all of which are intended to be embraced within the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method comprising providing a digital signal Sdrive having a square waveform and varying between a first voltage and a second voltage, maintaining a voltage of the signal Sdrive substantially constant at a third voltage that is between the first voltage and the second voltage for a period of time as said voltage of the digital signal Sdrive changes from the first voltage to the second voltage, and modulating at least one of a digital signal Scontrol and a digital signal Scorn with the digital signal Sdrive during said period of time.

2. A method according to claim 1 in which the third voltage has a value other than zero volts.

3. A method according to claim 1 or claim 2 wherein the third voltage is other than midway between the first voltage and the second voltage.

4. A method according to claim 3 wherein the third voltage is sufficiently high to enable a controller switch to function in the absence of the digital signal Sdrive, the controller switch being in electrical communication with a drive controller circuit which generates the digital signal Sdrive.

5. A method according to any of claims 1-4 in which the first voltage has a value greater than the second voltage, the signal Sdrive has a falling edge as Sdrive changes from the first voltage to the second voltage, and the period during which Sdrive is held substantially constant occurs on the falling edge of the signal Sdrive before the voltage of Sdrive is equal to the second voltage.

6. A system comprising a drive circuit in electrical communication with a digital drive controller circuit, wherein the drive controller circuit produces a digital electrical signal Sdrive having a square waveform varying between a first voltage and a second voltage, the first voltage providing a first potential sufficient to drive a first LED to emit a first color of light and having a second potential sufficient to drive a second LED to emit a second color of light, the second LED having a second polarity opposite to the first polarity; wherein the system further comprises a first controller switch configured to generate a first digital communication signal Scoml and to modulate the signal Scoml with at least one of Sdrive and Scontrol.

7. A system according to claim 6 wherein the first controller switch is configured to modulate the signal Scoml with Sdrive.

8. A system according to claim 7 further comprising a second controller switch configured to generate a second digital communication signal Scom2 that communicates a command to the drive controller circuit to change at least one of a luminance of the first LED and a luminance of the second LED, and wherein the second controller switch is configured to modulate the signal Scom2 with at least one of Sdrive and Scontrol.

9. A system according to claim 8 wherein the second controller switch is configured to modulate the signal Scom2 with Sdrive.

10. A system according to claim 6 wherein the first controller switch is configured to modulate the signal Scoml with Scontrol.

11. A system according to claim 8 wherein the second controller switch is configured to modulate the signal Scom2 with Scontrol.

12. A system according to any of claims 6-11 wherein the drive controller circuit is configured to provide a third voltage having a value other than zero volts and that is between the first voltage and the second voltage.

13. A system according to claim 12 wherein the drive controller circuit is configured to maintain a voltage of the signal Sdrive substantially constant at the third voltage for a period of time as said voltage of the digital signal Sdrive changes from the first voltage to the second voltage, and the first and second controller switches are configured to modulate at least one of the digital signals Scoml and Scom2 respectively with the digital signal Sdrive during said period of time.

14. A system according to claim 8 wherein the drive controller circuit comprises a radio to receive a digital signal Scom3 that is transmitted wirelessly.

15. A system according to any of claims 6-14 and further comprising a load circuit.

16. A system according to claim 15 wherein the first control switch is in electrical communication with both the load circuit and the drive controller circuit.

17. A system according to claim 15 or claim 16 wherein the load circuit comprises the first LED and the second LED.

18. A system according to any of claims 6-17 wherein the first controller switch is configured to communicate with the drive controller circuit to adjust a color setting.

19. A system according to any of claims 6-17 wherein the first controller switch is configured to communicate with the drive controller circuit to adjust light luminance.

20. A system according to any of claims 6-17 wherein , the first controller switch is configured to communicate with the drive controller circuit to adjust a color setting to follow a Circadian clock.

21. A system according to any of claims 6-17 and further comprising a timer to control the drive controller circuit.

22. A system according to any of claims 6-17 and further comprising a motion sensor to control the drive controller circuit in response to said motion.

23. A system of claims 6-17 where the controller switch indicates the system status.