US20070030714A1 - Enabling Circuit for Avoiding Negative Voltage Transients - Google Patents
Enabling Circuit for Avoiding Negative Voltage Transients Download PDFInfo
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- US20070030714A1 US20070030714A1 US11/535,173 US53517306A US2007030714A1 US 20070030714 A1 US20070030714 A1 US 20070030714A1 US 53517306 A US53517306 A US 53517306A US 2007030714 A1 US2007030714 A1 US 2007030714A1
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- charge
- capacitor
- enabling
- circuit
- converter
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1588—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load comprising at least one synchronous rectifier element
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J2207/20—Charging or discharging characterised by the power electronics converter
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B40/00—Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Definitions
- This invention relates to an enabling circuit for avoiding negative voltage transients from an associated regulating circuit, and more particularly to such an enabling circuit for enabling a synchronous rectifier converter to switch from a first state to second state if the charge on an energy storage element of the synchronous rectifier converter is less than a reference charge.
- a variety of circuits have energy storage element such as capacitors, inductors, and transformers that transfer energy from an input to an output of such circuits. If such energy storage elements are not properly discharged in some instances, unwanted power disturbances, e.g., negative voltage transients, may occur in the output signal causing damage to nearby sensitive components.
- energy storage element such as capacitors, inductors, and transformers that transfer energy from an input to an output of such circuits. If such energy storage elements are not properly discharged in some instances, unwanted power disturbances, e.g., negative voltage transients, may occur in the output signal causing damage to nearby sensitive components.
- such a regulating circuit may be a DC-DC converter.
- DC-DC converters generally accept a DC input at one voltage level and convert it to a DC output at a higher or lower voltage level.
- Such DC-DC converters may be used in a wide variety of electronic devices in conjunction with a variety of systems.
- One such system may be used to provide a battery charging function for portable electronic devices such as laptop computers, cell phones, pagers, personal digital assistants, and the like.
- An SRC does not use any Schottky diodes, but rather uses transistors referred to as “synchronous rectifiers.” Such transistors may be a variety of transistors such as MOS or MOSFET transistors.
- An SRC may also have a variety of internal components that typically include an energy storage element, e.g., a capacitor, inductor, or transformer, with one or more transistors controlled by various control techniques, e.g., pulse width modulation where the switch frequency is constant and the duty cycle varies with the load.
- the SRC may accept an input voltage from a number of different power sources and convert it to an appropriate output voltage to, among other things, provide an appropriate charging current to an associated rechargeable battery.
- a controller used to control the battery charging process.
- controller may be an integrated circuit (IC) having a plurality of input terminals or pins, some of which are connected to the output of the SRC. For instance, two such terminals may be coupled to either side of a sense resistor.
- the sense resistor may be in series with the output of the SRC such that it provides a signal representative of the charging current provided at the output of the SRC.
- an enabling circuit for enabling a DC-DC converter having a capacitor coupled to an output terminal of the DC-DC converter to be controlled by a control signal.
- the enabling circuit may include a comparison circuit configured to compare a feedback signal representative of a charge on the capacitor with a signal representative of a reference charge and to provide an output to in response to the comparison to enable the DC-DC converter to be controlled by the control signal if the charge on the capacitor is less than the reference charge.
- the enabling circuit may also include a discharge path configured to discharge the charge on the capacitor if the charge is greater than the reference charge.
- the system may include a DC-DC converter configured to accept an input power level from a power source and provide a regulated output power level to a load.
- the DC-DC converter may have a capacitor coupled to an output terminal of the DC-DC converter.
- the system may further include an enabling circuit for enabling the DC-DC converter to be controlled by a control signal.
- the enabling circuit may include a comparison circuit configured to compare a feedback signal representative of a charge on the capacitor with a signal representative of a reference charge and to provide an output to in response to the comparison to enable the DC-DC converter to be controlled by the control signal if the charge on the capacitor is less than the reference charge.
- the enabling circuit may also include a discharge path configured to discharge the charge on the capacitor if the charge is greater than the reference charge.
- the method may include monitoring a charge on a capacitor of a DC-DC converter coupled to an output terminal of said DC-DC converter; preventing the DC-DC converter from being controlled by a control signal if the charge is greater than the reference charge; and enabling the DC-DC converter to be controlled by the control signal if the charge is less than the reference charge.
- FIG. 1 is a block diagram of a system including an enabling circuit consistent with the present invention for enabling an associated regulating circuit to switch from a first state to a second state;
- FIG. 2 is a block diagram of an exemplary enabling circuit consistent with the invention for enabling an associated synchronous rectifier converter to switch from one state to another state;
- FIG. 2A is a circuit diagram illustrating an exemplary embodiment of the enabling circuit of FIG. 2 ;
- FIG. 3 is a block diagram of a battery management system utilizing the enabling circuit of FIG. 2 .
- the regulating circuit 102 may be any variety of circuits, e.g., a synchronous rectifier converter, containing an energy storage element 106 , e.g., a capacitor.
- the enabling circuit 104 monitors the charge on the energy storage element 106 and enables the regulating circuit 102 to switch from a first state to a second state when the charge on the energy storage element is below a reference charge.
- the first state may be any variety of states such as a power off state
- the second state may also be any variety of states such as an operating state where the regulating circuit 102 is controlled by a particular control technique.
- the reference charge should be chosen based on the particular system and sensitivity of associated components. In one embodiment, the reference charge may be 3.0 volts.
- the enabling circuit 104 has one input terminal 107 configured to accept a signal, Vdsch, representative of an acceptable reference charge level for the energy storage element 106 .
- the enabling circuit 104 may have another input terminal 109 configured to accept a logic control signal chginh.
- Such logic control signal, chginh has a predetermined state, e.g., low state, when at least one non energy storage element condition related to operation of the regulating circuit 102 is satisfied.
- a condition or conditions may be any variety of other conditions known to those skilled in the art unrelated to the charge on the energy storage element 106 . For instance, one condition may be the proper coupling of an input power source at a proper power level to the input of the regulating circuit 102 .
- the enabling circuit 104 accepts a feedback signal from the regulating circuit 102 along path 119 . Such feedback signal is representative of the charge on the energy storage element 106 .
- the enabling circuit compares the charge on energy storage element 106 with a reference charge and may output an enabling signal if the charge level is less than the reference charge level.
- the enabling circuit 104 may also include various discharging means as further described in reference to FIG. 2 in order to discharge the energy storage element 106 below the reference charge level should the charge be greater than the reference charge level.
- the enabling circuit 104 sends an enabling signal along path 115 to the controller 120 .
- the controller 120 is responsive to the enabling signal to then enable the regulating circuit to switch from a first state, e.g., a non-operating state or a predetermined suitable operating state, to a second state, e.g., another operating state.
- a first state e.g., a non-operating state or a predetermined suitable operating state
- a second state e.g., another operating state.
- an enabling circuit 104 consistent with the invention may advantageously delay operation of the regulating circuit 102 in the second state while maintaining operation of the regulating circuit 102 in the first state until the energy storage element 106 is discharged below a reference charge.
- the enabling circuit 104 may not send an enabling signal to the controller 120 until both the energy storage element 106 is discharged below the reference charge level and a logic control signal, e.g., signal chginh, input to the enabling circuit is at a predetermined state.
- a logic control signal e.g., signal chginh
- Such predetermined state is representative of at least one satisfactory non energy storage element condition.
- Such predetermined state may also be representative of a satisfactory condition for all other non energy storage element conditions.
- an enabling circuit 104 consistent with the invention delays switching the regulating circuit 102 to operation in the second state while maintaining operation of the regulating circuit 102 in the first state, e.g., a non-operating state or a predetermined suitable operating state, until the energy storage element 106 is discharged below a predetermined charge level and a signal representing at least one satisfactory non energy storage element condition related to operation of the regulating circuit is satisfied.
- the first state e.g., a non-operating state or a predetermined suitable operating state
- FIG. 2 one exemplary system 200 having an enabling circuit 204 consistent with the invention and a synchronous rectifier converter (SRC) 202 is illustrated.
- the SRC accepts an input voltage signal at input terminal 226 and provides an output voltage signal at output terminal 211 .
- the SRC may include an inductor 208 , a capacitor 206 and switches K 1 , K 2 .
- Switches K 1 , K 2 may be any type of transistors and for simplicity are drawn to represent MOS type transistors.
- Such switches K 1 , K 2 may be controlled by a variety of control techniques such as pulse width modulation (PWM) where the switch frequency is constant and the duty cycle varies with load, pulse-frequency modulation, or current-limited pulse-frequency modulation as those control techniques are known to those skilled in the art.
- PWM pulse width modulation
- the enabling circuit 204 may include a comparator circuit 232 , an output decision circuit 234 , and discharge path including resistors R 1 , R 2 and switches K 3 , K 4 .
- the comparator circuit 232 may be any variety of circuits for comparing the charge on the capacitor 206 to a predetermined reference value charge represented by control signal Vdsch input to the comparator circuit.
- the comparator circuit 232 is configured to provide an output signal to maintain the SRC 202 in the first state, e.g., a non-operating state or a predetermined suitable operating state, if the charge on the capacitor 206 is higher than the reference charge.
- the comparator circuit 232 is also configured to provide output signal to switch the SRC 202 from the first state to a second state, e.g., another operating state where switches K 1 , K 2 are under control of the controller 220 , if the charge on the capacitor 206 is less than the reference charge.
- the output decision circuit 234 may be any variety of circuits for performing a desired logic function.
- the output decision circuit 234 accepts the output signal dsch from the comparator circuit 232 and may further accept a logic signal chginh from a separate source.
- the output decision circuit 234 may be configured to output an enabling signal on path 215 to the controller 220 if signal dsch indicates the charge on the capacitor 206 is less than a reference charge level.
- the output decision circuit 234 may alternately require signal dsch to indicate the charge on the capacitor 206 is less than a reference charge level, and require signal chginh to be in a predetermined state, e.g., low state, when at least one non energy storage element condition is satisfied.
- the output decision circuit 234 is not a necessary part of the enabling circuit 204 if the logic signal chginh is not input to the enabling circuit. In this case, the comparator circuit 232 would provide the enabling signal if the charge on the capacitor 206 is less than the reference charge.
- the enabling circuit 204 may also include a discharge path including resistors R 1 , R 2 , and switches K 3 , K 4 to discharge the capacitor 206 below a reference level.
- Switches K 3 , K 4 may be any type of transistors and for simplicity are drawn to represent MOS type transistors. Detailed operation of an enabling circuit and the discharge path is made later with reference to the exemplary enabling circuit of FIG. 2A .
- FIG. 2A a circuit diagram of one exemplary enabling circuit 204 a is illustrated.
- the comparator circuit 232 of FIG. 2 includes a comparator 232 a having its positive input terminal accepting the input signal representative of the charge on the capacitor 206 and its negative input terminal accepting the other input control signal, Vdsch, representative of a reference value charge.
- the output decision circuit 234 includes a NOR gate 234 a.
- the NOR gate 234 a accepts the output from the comparator 232 a and the control signal chginh.
- the output of the NOR gate 234 a is HIGH only if all inputs are LOW. Otherwise, the output of the NOR gate 234 a is LOW.
- the enabling signal sent by the enabling circuit 204 to the controller 220 to enable the regulating circuit 202 to switch from the first state, e.g. switches K 1 , K 2 open, to the second state state, e.g., switches K 1 , K 2 under control of controller 220 is sent when the output of the NOR gate is HIGH.
- Table 1 details the status of the various control signals and switches relative to each other with the output decision circuit 234 functioning as the NOR gate 234 a of FIG. 2A .
- the status of control signal chginh input to the enabling circuit 204 , control signal dsch output from comparator 232 a, control signal chgen output from the NOR gate 234 a, switches K 1 , K 2 of the SRC 202 , and switches K 3 , K 4 of the enabling circuit 204 are all detailed in Table 1.
- TABLE 1 chginh H H L L L dsch H L H L chgen L L L L H K1 OFF OFF OFF PWM K2 OFF OFF OFF PWM K3 ON ON ON OFF K4 ON ON ON ON OFF
- the exemplary enabling circuit 204 a advantageously does not enable switches K 1 , K 2 of the SRC 204 to be controlled by the proper control technique, e.g., PWM control, and maintains switches K 1 , K 2 in an OFF position, until the capacitor 206 of the SRC 202 is discharged below a reference charge (control signal dsch is L), and at least one other non capacitor charge related condition for operation of the regulating circuit (control signal chginh is L) is satisfied.
- control signal dsch is L
- control signal chginh is L
- the other input to the NOR gate 234 a may be the control signal chginh from a separate source.
- control signal chginh is representative of at least one non capacitor related condition pertinent to operation of the SRC 202 .
- this chginh signal is LOW, at least one and perhaps all other non capacitor related conditions pertinent to operation of the SRC 202 are satisfactory. If this chginh signal is HIGH, such condition or conditions are unsatisfactory. Accordingly, if the output control signal dsch from the comparator 232 a is HIGH and the chginh signal is also HIGH, the output signal from the NOR gate 234 a is LOW.
- switches K 1 and K 2 remain OFF or open and the operation of the SRC 202 is delayed. As such, if the SRC is operating to provide a charging current to an associated rechargeable battery, such charging current would not be provided in this instance, nor would current flow from the capacitor 206 through the inductor 208 be possible in this instance.
- switches K 3 , K 4 are closed or in an ON position. A discharge path for the capacitor 206 is then created through the switches K 3 , K 4 .
- Switch K 3 is further coupled in series to resistor R 1
- switch K 4 is further coupled in series to resistor R 2 .
- Resistor R 1 has a resistive value that is higher than the resistive value for resistor R 2 .
- an exemplary battery charging system 300 generally including a power source 344 , an SRC 302 , an enabling circuit 304 consistent with the invention, a rechargeable battery 340 , and a battery charging controller 320 is illustrated.
- a battery charging system 300 may be used in a variety of portable electronic devices such as laptop computers, cell phones, pagers, personal digital assistants, and the like to provide and control power flow to a rechargeable battery 340 , e.g., a lithium, nickel-cadmium, or nickel-metal hydride battery.
- a sensor such as sense resistor 346 may be used in order to provide a sensed signal to the controller 320 indicative of the charging current Ichg to the battery.
- a controller 320 is typically an integrated circuit (IC) and may be sensitive to negative voltage transients that may otherwise occur at either terminal 349 , 351 if the energy storage element 306 is not properly discharged below a reference charge value. Such negative voltage transients may appear on either terminal 349 , 351 due to oscillation induced by an inductor and capacitor group of the SRC 302 .
- the power source 344 may be an AC/DC adapter configured to receive conventional AC voltage from a power outlet and convert it to an applicable DC voltage, or a DC/DC adapter such as a “cigarette lighter” type adapter configured to plug into that type of socket, or other types of power sources.
- the SRC 302 accepts power input from the power source 344 and converts it to a proper output voltage and current level for providing a charging current Ichg to the battery 340 only if the controller 320 receives an enabling signal from the enabling circuit 304 along path 315 . Otherwise, the controller 320 delays providing a charging current Ichg to the battery 340 , while keeping the SRC 302 in a predetermined suitable state.
- This predetermined suitable state may be any variety of states as determined by the position of various switches in the SRC 302 . In the previous embodiment of FIG. 2 , switches K 1 , K 2 of SRC 202 were chosen to be in an open state.
- the SRC 302 is controlled by the controller 320 by any variety of control techniques, e.g., PWM, known by those skilled in the art.
- the enabling circuit 304 delays providing of the charging current Ichg to the battery 340 until the energy storage element 306 is discharged below a reference charge.
- the enabling circuit 304 may also further delay the charging current Ichg to the battery 340 until another control signal, e.g., signal chginh, from another source indicates that at least one non-charge related condition pertinent to operation of the SRC 302 is satisfactory.
Abstract
An enabling circuit for enabling a DC-DC converter having a capacitor coupled to an output terminal of the DC-DC converter to be controlled by a control signal. The enabling circuit may include a comparison circuit configured to compare a feedback signal representative of a charge on the capacitor with a signal representative of a reference charge and to provide an output to in response to the comparison to enable the DC-DC converter to be controlled by the control signal if the charge on the capacitor is less than the reference charge. The enabling circuit may also include a discharge path configured to discharge the charge on the capacitor if the charge is greater than the reference charge. A related system and method are also provided.
Description
- This application is a continuation of prior application Ser. No. 11/142,505 filed Jun. 1, 2005, now U.S. Pat. No. 7,112,943, which itself is a continuation of prior application Ser. No. 10/738,058 filed Dec. 17, 2003, now U.S. Pat. No. 6,906,497, which itself is a continuation of prior application Ser. No. 10/176,141, filed Jun. 20, 2002, now U.S. Pat. No. 6,756,769, the teachings of which are incorporated herein by reference.
- This invention relates to an enabling circuit for avoiding negative voltage transients from an associated regulating circuit, and more particularly to such an enabling circuit for enabling a synchronous rectifier converter to switch from a first state to second state if the charge on an energy storage element of the synchronous rectifier converter is less than a reference charge.
- A variety of circuits have energy storage element such as capacitors, inductors, and transformers that transfer energy from an input to an output of such circuits. If such energy storage elements are not properly discharged in some instances, unwanted power disturbances, e.g., negative voltage transients, may occur in the output signal causing damage to nearby sensitive components.
- For instance, such a regulating circuit may be a DC-DC converter. DC-DC converters generally accept a DC input at one voltage level and convert it to a DC output at a higher or lower voltage level. Such DC-DC converters may be used in a wide variety of electronic devices in conjunction with a variety of systems. One such system may be used to provide a battery charging function for portable electronic devices such as laptop computers, cell phones, pagers, personal digital assistants, and the like.
- One type of DC-DC converter is a synchronous rectifier converter (SRC). An SRC does not use any Schottky diodes, but rather uses transistors referred to as “synchronous rectifiers.” Such transistors may be a variety of transistors such as MOS or MOSFET transistors. An SRC may also have a variety of internal components that typically include an energy storage element, e.g., a capacitor, inductor, or transformer, with one or more transistors controlled by various control techniques, e.g., pulse width modulation where the switch frequency is constant and the duty cycle varies with the load.
- When an SRC is used in conjunction with a battery power management system, the SRC may accept an input voltage from a number of different power sources and convert it to an appropriate output voltage to, among other things, provide an appropriate charging current to an associated rechargeable battery. In such a battery power management system, there is typically an associated controller used to control the battery charging process. Such controller may be an integrated circuit (IC) having a plurality of input terminals or pins, some of which are connected to the output of the SRC. For instance, two such terminals may be coupled to either side of a sense resistor. The sense resistor may be in series with the output of the SRC such that it provides a signal representative of the charging current provided at the output of the SRC.
- If a soft start occurs when the energy storage element, e.g., a capacitor, of the SRC is charged at a significant value, e.g., over several volts, negative voltage transients may appear on either terminal of the sense resistor potentially causing catastrophic failure of the associated controller IC. Accordingly, there is a need for an enabling circuit and method that overcomes the above deficiencies in the prior art and is capable of avoiding negative voltage transients from an associated regulating circuit by enabling the regulating circuit only when the charge on the energy storage element is below a reference charge.
- According to one aspect of the invention, there is provided an enabling circuit for enabling a DC-DC converter having a capacitor coupled to an output terminal of the DC-DC converter to be controlled by a control signal. The enabling circuit may include a comparison circuit configured to compare a feedback signal representative of a charge on the capacitor with a signal representative of a reference charge and to provide an output to in response to the comparison to enable the DC-DC converter to be controlled by the control signal if the charge on the capacitor is less than the reference charge. The enabling circuit may also include a discharge path configured to discharge the charge on the capacitor if the charge is greater than the reference charge.
- According to another aspect of the invention, there is provided a system. The system may include a DC-DC converter configured to accept an input power level from a power source and provide a regulated output power level to a load. The DC-DC converter may have a capacitor coupled to an output terminal of the DC-DC converter. The system may further include an enabling circuit for enabling the DC-DC converter to be controlled by a control signal. The enabling circuit may include a comparison circuit configured to compare a feedback signal representative of a charge on the capacitor with a signal representative of a reference charge and to provide an output to in response to the comparison to enable the DC-DC converter to be controlled by the control signal if the charge on the capacitor is less than the reference charge. The enabling circuit may also include a discharge path configured to discharge the charge on the capacitor if the charge is greater than the reference charge.
- According to yet another aspect of the invention there is provided a method. The method may include monitoring a charge on a capacitor of a DC-DC converter coupled to an output terminal of said DC-DC converter; preventing the DC-DC converter from being controlled by a control signal if the charge is greater than the reference charge; and enabling the DC-DC converter to be controlled by the control signal if the charge is less than the reference charge.
- For a better understanding of the present invention, together with other objects, features and advantages, reference should be made to the following detailed description which should be read in conjunction with the following figures wherein like numerals represent like parts:
-
FIG. 1 is a block diagram of a system including an enabling circuit consistent with the present invention for enabling an associated regulating circuit to switch from a first state to a second state; -
FIG. 2 is a block diagram of an exemplary enabling circuit consistent with the invention for enabling an associated synchronous rectifier converter to switch from one state to another state; -
FIG. 2A is a circuit diagram illustrating an exemplary embodiment of the enabling circuit ofFIG. 2 ; and -
FIG. 3 is a block diagram of a battery management system utilizing the enabling circuit ofFIG. 2 . - Turning to
FIG. 1 , anexemplary system 100 including an enablingcircuit 104 and an associated regulatingcircuit 102 is illustrated. The regulatingcircuit 102 may be any variety of circuits, e.g., a synchronous rectifier converter, containing anenergy storage element 106, e.g., a capacitor. In general, the enablingcircuit 104 monitors the charge on theenergy storage element 106 and enables the regulatingcircuit 102 to switch from a first state to a second state when the charge on the energy storage element is below a reference charge. The first state may be any variety of states such as a power off state, and the second state may also be any variety of states such as an operating state where the regulatingcircuit 102 is controlled by a particular control technique. The reference charge should be chosen based on the particular system and sensitivity of associated components. In one embodiment, the reference charge may be 3.0 volts. - The enabling
circuit 104 has oneinput terminal 107 configured to accept a signal, Vdsch, representative of an acceptable reference charge level for theenergy storage element 106. The enablingcircuit 104 may have anotherinput terminal 109 configured to accept a logic control signal chginh. Such logic control signal, chginh, has a predetermined state, e.g., low state, when at least one non energy storage element condition related to operation of the regulatingcircuit 102 is satisfied. Such a condition or conditions may be any variety of other conditions known to those skilled in the art unrelated to the charge on theenergy storage element 106. For instance, one condition may be the proper coupling of an input power source at a proper power level to the input of the regulatingcircuit 102. - The enabling
circuit 104 accepts a feedback signal from the regulatingcircuit 102 alongpath 119. Such feedback signal is representative of the charge on theenergy storage element 106. The enabling circuit compares the charge onenergy storage element 106 with a reference charge and may output an enabling signal if the charge level is less than the reference charge level. The enablingcircuit 104 may also include various discharging means as further described in reference toFIG. 2 in order to discharge theenergy storage element 106 below the reference charge level should the charge be greater than the reference charge level. - In one embodiment, once the charge on the
energy storage element 106 is below the reference charge, the enablingcircuit 104 sends an enabling signal alongpath 115 to thecontroller 120. Thecontroller 120 is responsive to the enabling signal to then enable the regulating circuit to switch from a first state, e.g., a non-operating state or a predetermined suitable operating state, to a second state, e.g., another operating state. As such, an enablingcircuit 104 consistent with the invention may advantageously delay operation of the regulatingcircuit 102 in the second state while maintaining operation of the regulatingcircuit 102 in the first state until theenergy storage element 106 is discharged below a reference charge. - In another embodiment, the enabling
circuit 104 may not send an enabling signal to thecontroller 120 until both theenergy storage element 106 is discharged below the reference charge level and a logic control signal, e.g., signal chginh, input to the enabling circuit is at a predetermined state. Such predetermined state is representative of at least one satisfactory non energy storage element condition. Such predetermined state may also be representative of a satisfactory condition for all other non energy storage element conditions. In this case, an enablingcircuit 104 consistent with the invention delays switching the regulatingcircuit 102 to operation in the second state while maintaining operation of the regulatingcircuit 102 in the first state, e.g., a non-operating state or a predetermined suitable operating state, until theenergy storage element 106 is discharged below a predetermined charge level and a signal representing at least one satisfactory non energy storage element condition related to operation of the regulating circuit is satisfied. - Turning to
FIG. 2 , oneexemplary system 200 having an enablingcircuit 204 consistent with the invention and a synchronous rectifier converter (SRC) 202 is illustrated. The SRC accepts an input voltage signal atinput terminal 226 and provides an output voltage signal atoutput terminal 211. The SRC may include aninductor 208, acapacitor 206 and switches K1, K2. Switches K1, K2 may be any type of transistors and for simplicity are drawn to represent MOS type transistors. Such switches K1, K2 may be controlled by a variety of control techniques such as pulse width modulation (PWM) where the switch frequency is constant and the duty cycle varies with load, pulse-frequency modulation, or current-limited pulse-frequency modulation as those control techniques are known to those skilled in the art. - The enabling
circuit 204 may include acomparator circuit 232, anoutput decision circuit 234, and discharge path including resistors R1, R2 and switches K3, K4. Thecomparator circuit 232 may be any variety of circuits for comparing the charge on thecapacitor 206 to a predetermined reference value charge represented by control signal Vdsch input to the comparator circuit. Thecomparator circuit 232 is configured to provide an output signal to maintain theSRC 202 in the first state, e.g., a non-operating state or a predetermined suitable operating state, if the charge on thecapacitor 206 is higher than the reference charge. Thecomparator circuit 232 is also configured to provide output signal to switch theSRC 202 from the first state to a second state, e.g., another operating state where switches K1, K2 are under control of thecontroller 220, if the charge on thecapacitor 206 is less than the reference charge. - The
output decision circuit 234 may be any variety of circuits for performing a desired logic function. Theoutput decision circuit 234 accepts the output signal dsch from thecomparator circuit 232 and may further accept a logic signal chginh from a separate source. Theoutput decision circuit 234 may be configured to output an enabling signal onpath 215 to thecontroller 220 if signal dsch indicates the charge on thecapacitor 206 is less than a reference charge level. Theoutput decision circuit 234 may alternately require signal dsch to indicate the charge on thecapacitor 206 is less than a reference charge level, and require signal chginh to be in a predetermined state, e.g., low state, when at least one non energy storage element condition is satisfied. Theoutput decision circuit 234 is not a necessary part of the enablingcircuit 204 if the logic signal chginh is not input to the enabling circuit. In this case, thecomparator circuit 232 would provide the enabling signal if the charge on thecapacitor 206 is less than the reference charge. - The enabling
circuit 204 may also include a discharge path including resistors R1, R2, and switches K3, K4 to discharge thecapacitor 206 below a reference level. Switches K3, K4 may be any type of transistors and for simplicity are drawn to represent MOS type transistors. Detailed operation of an enabling circuit and the discharge path is made later with reference to the exemplary enabling circuit ofFIG. 2A . - Turning to
FIG. 2A , a circuit diagram of one exemplary enablingcircuit 204 a is illustrated. Those skilled in the art will recognize a variety of circuit configurations which may be utilized in an enabling circuit consistent with the present invention. In the exemplary embodiment ofFIG. 2A , thecomparator circuit 232 ofFIG. 2 includes acomparator 232 a having its positive input terminal accepting the input signal representative of the charge on thecapacitor 206 and its negative input terminal accepting the other input control signal, Vdsch, representative of a reference value charge. - The
output decision circuit 234 includes a NORgate 234 a. The NORgate 234 a accepts the output from thecomparator 232 a and the control signal chginh. The output of the NORgate 234 a is HIGH only if all inputs are LOW. Otherwise, the output of the NORgate 234 a is LOW. In this embodiment, the enabling signal sent by the enablingcircuit 204 to thecontroller 220 to enable the regulatingcircuit 202 to switch from the first state, e.g. switches K1, K2 open, to the second state state, e.g., switches K1, K2 under control ofcontroller 220, is sent when the output of the NOR gate is HIGH. - Operation of the exemplary enabling
circuit 204 a in conjunction with thesystem 200 is described further herein with reference to the Truth Table of Table 1. Table 1 details the status of the various control signals and switches relative to each other with theoutput decision circuit 234 functioning as the NORgate 234 a ofFIG. 2A . The status of control signal chginh input to the enablingcircuit 204, control signal dsch output fromcomparator 232 a, control signal chgen output from the NORgate 234 a, switches K1, K2 of theSRC 202, and switches K3, K4 of the enablingcircuit 204 are all detailed in Table 1.TABLE 1 chginh H H L L dsch H L H L chgen L L L H K1 OFF OFF OFF PWM K2 OFF OFF OFF PWM K3 ON ON ON OFF K4 ON ON ON OFF - As illustrated and described more fully herein, the exemplary enabling
circuit 204 a advantageously does not enable switches K1, K2 of theSRC 204 to be controlled by the proper control technique, e.g., PWM control, and maintains switches K1, K2 in an OFF position, until thecapacitor 206 of theSRC 202 is discharged below a reference charge (control signal dsch is L), and at least one other non capacitor charge related condition for operation of the regulating circuit (control signal chginh is L) is satisfied. As such, negative voltage transients that may otherwise occur at theoutput terminal 211 of theSRC 202 are avoided. - As illustrated in the first substantive column of Table 1, if the charge level on
capacitor 206 is greater than a reference charge level as represented by control signal Vdsch input to thecomparator 232 a, then the control signal dsch output from thecomparator 232 a is HIGH. The output control signal dsch from thecomparator 232 a is then input to the NORgate 234 a. - The other input to the NOR
gate 234 a may be the control signal chginh from a separate source. Such control signal chginh is representative of at least one non capacitor related condition pertinent to operation of theSRC 202. In this embodiment, if this chginh signal is LOW, at least one and perhaps all other non capacitor related conditions pertinent to operation of theSRC 202 are satisfactory. If this chginh signal is HIGH, such condition or conditions are unsatisfactory. Accordingly, if the output control signal dsch from thecomparator 232 a is HIGH and the chginh signal is also HIGH, the output signal from the NORgate 234 a is LOW. Thus, switches K1 and K2 remain OFF or open and the operation of theSRC 202 is delayed. As such, if the SRC is operating to provide a charging current to an associated rechargeable battery, such charging current would not be provided in this instance, nor would current flow from thecapacitor 206 through theinductor 208 be possible in this instance. - Turning to the second substantive column of Table 1, if the
capacitor 206 is discharged below the reference charge represented by control signal Vdsch, the output control signal dsch from thecomparator 232 a goes LOW indicating the charge level on thecapacitor 206 is acceptable. However, if another non capacitor charge related condition is unsatisfactory, the control signal chginh remains HIGH. As such, the output of the NORgate 234 a remains LOW and the operation of theSRC 202 is still delayed. - Turning to the third substantive column of Table 1, if the control signal chginh is LOW representing a satisfactory starting condition for at least one non-charge related condition, but the output control signal dsch from the
comparator 232 a is HIGH, then the output signal chgen from the NORgate 234 a remains LOW. As such, the operation of theSRC 202 is still delayed. - As illustrated in the fourth substantive column of Table 1, it is not until the
capacitor 206 is discharged below the reference charge level (control signal dsch output from thecomparator 232 a is LOW), and at least one if not all other non-charge related conditions for operation of the regulating circuit (control signal chginh is LOW) are satisfied, that the control signal chgen output of the NORgate 234 a is HIGH. Once the control signal chgen is HIGH, switches K3 and K4 of the enablingcircuit 204 open or are in an OFF position. The HIGH control signal chgen enables thecontroller 220 to drive theSRC 202. Hence, switches K1, K2 are controlled by an appropriate control technique, e.g., PWM. - If the enabling signal is not present in this embodiment, switches K3, K4 are closed or in an ON position. A discharge path for the
capacitor 206 is then created through the switches K3, K4. Switch K3 is further coupled in series to resistor R1, while switch K4 is further coupled in series to resistor R2. Resistor R1 has a resistive value that is higher than the resistive value for resistor R2. As such, when switches K3, K4 are closed because no enabling signal from the NORgate 234 a is present, a discharge path is created and resistor R2 serves to discharge thecapacitor 206. - Turning to
FIG. 3 , an exemplary battery charging system 300 generally including apower source 344, anSRC 302, an enablingcircuit 304 consistent with the invention, arechargeable battery 340, and abattery charging controller 320 is illustrated. Such a battery charging system 300 may be used in a variety of portable electronic devices such as laptop computers, cell phones, pagers, personal digital assistants, and the like to provide and control power flow to arechargeable battery 340, e.g., a lithium, nickel-cadmium, or nickel-metal hydride battery. - A sensor such as
sense resistor 346 may be used in order to provide a sensed signal to thecontroller 320 indicative of the charging current Ichg to the battery. Such acontroller 320 is typically an integrated circuit (IC) and may be sensitive to negative voltage transients that may otherwise occur at either terminal 349, 351 if theenergy storage element 306 is not properly discharged below a reference charge value. Such negative voltage transients may appear on either terminal 349, 351 due to oscillation induced by an inductor and capacitor group of theSRC 302. - Once a
power source 344 is properly coupled to the system 300, it provides an input DC voltage signal to theSRC 302. Thepower source 344 may be an AC/DC adapter configured to receive conventional AC voltage from a power outlet and convert it to an applicable DC voltage, or a DC/DC adapter such as a “cigarette lighter” type adapter configured to plug into that type of socket, or other types of power sources. - Advantageously, the
SRC 302 accepts power input from thepower source 344 and converts it to a proper output voltage and current level for providing a charging current Ichg to thebattery 340 only if thecontroller 320 receives an enabling signal from the enablingcircuit 304 alongpath 315. Otherwise, thecontroller 320 delays providing a charging current Ichg to thebattery 340, while keeping theSRC 302 in a predetermined suitable state. This predetermined suitable state may be any variety of states as determined by the position of various switches in theSRC 302. In the previous embodiment ofFIG. 2 , switches K1, K2 ofSRC 202 were chosen to be in an open state. TheSRC 302 is controlled by thecontroller 320 by any variety of control techniques, e.g., PWM, known by those skilled in the art. - Advantageously therefore, the enabling
circuit 304 delays providing of the charging current Ichg to thebattery 340 until theenergy storage element 306 is discharged below a reference charge. The enablingcircuit 304 may also further delay the charging current Ichg to thebattery 340 until another control signal, e.g., signal chginh, from another source indicates that at least one non-charge related condition pertinent to operation of theSRC 302 is satisfactory. - The embodiments that have been described herein, however, are but some of the several which utilize this invention and are set forth here by way of illustration but not of limitation. It is obvious that many other embodiments, which will be readily apparent to those skilled in the art, may be made without departing materially from the spirit and scope of the invention.
Claims (18)
1. An enabling circuit for enabling a DC-DC converter having a capacitor coupled to an output terminal of said DC-DC converter to be controlled by a control signal, said enabling circuit comprising:
a comparison circuit configured to compare a feedback signal representative of a charge on said capacitor with a signal representative of a reference charge and to provide an output in response to said comparison to prevent said DC-DC converter from being controlled by said control signal if said charge on said capacitor is greater than said reference charge.
2. The enabling circuit of claim 1 , wherein said comparison circuit comprises a discharge path configured to discharge said charge on said capacitor if said charge is greater than said reference charge.
3. The enabling circuit of claim 2 , wherein said discharge path comprises at least one switch, said at least one switch configured to close to create said discharge path from said capacitor if said charge on said capacitor is greater than said reference charge.
4. The enabling circuit of claim 3 , further comprising an output decision circuit configured to receive at least said output from said comparison circuit and provide an enabling signal to enable said DC-DC converter to switch from a first state wherein said DC-DC converter is not controlled by said control signal to a second state wherein said DC-DC converter is controlled by said control signal if said charge on said capacitor is less than said reference charge.
5. The enabling circuit of claim 4 , wherein said output decision circuit is further configured to receive a condition signal, and wherein said output decision circuit provides said enabling signal in response to said condition signal.
6. The enabling circuit of claim 4 , wherein said comparison circuit comprises a comparator.
7. The enabling circuit of claim 1 wherein said comparison circuit is configured to enable said DC-DC converter to be controlled by said control signal if said charge on said capacitor is less than said reference charge.
8. A system comprising:
a DC-DC converter configured to accept an input power level from a power source and provide a regulated output power level to a load, said DC-DC converter having a capacitor coupled to an output terminal of said DC-DC converter; and
an enabling circuit for enabling said DC-DC converter to be controlled by a control signal, said enabling circuit comprising:
a comparison circuit configured to compare a feedback signal representative of a charge on said capacitor with a signal representative of a reference charge and to provide an output in response to said comparison to prevent said DC-DC converter from being controlled by said control signal if said charge on said capacitor is greater than said reference charge.
9. The system of claim 8 , wherein said comparison circuit comprises a discharge path configured to discharge said charge on said capacitor if said charge is greater than said reference charge.
10. The system of claim 9 , wherein said discharge path comprises at least one switch, said at least one switch configured to close to create said discharge path from said capacitor if said charge on said capacitor is greater than said reference charge.
11. The system of claim 9 , further comprising an output decision circuit configured to receive at least said output from said comparison circuit and provide an enabling signal to enable said DC-DC converter to switch from a first state wherein said DC-DC converter is not controlled by said control signal to a second state wherein said DC-DC converter is controlled by said control signal if said charge on said capacitor is less than said reference charge.
12. The enabling circuit of claim 11 , wherein said output decision circuit is further configured to receive a condition signal, and wherein said output decision circuit provides said enabling signal in response to said condition signal.
13. The system of claim 8 , wherein said comparison circuit comprises a comparator.
14. The system of claim 8 wherein said comparison circuit is configured to enable said DC-DC converter to be controlled by said control signal if said charge on said capacitor is less than said reference charge.
15. A method comprising:
monitoring a charge on a capacitor of a DC-DC converter coupled to an output terminal of said DC-DC converter;
preventing charging of said capacitor if said charge of said capacitor is greater than a reference charge; and
enabling said DC-DC converter to be controlled by a control signal if said charge of said capacitor is less than said reference charge.
16. The method of claim 15 , further comprising discharging said capacitor if said charge is greater than said reference charge.
17. The method of claim 16 , wherein said discharge operation further comprises closing a switch to create a discharge path from said capacitor to ground.
18. The method of claim 15 wherein said enabling step occurs if at least one non capacitor condition is satisfied.
Priority Applications (1)
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US11/535,173 US20070030714A1 (en) | 2002-06-20 | 2006-09-26 | Enabling Circuit for Avoiding Negative Voltage Transients |
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US10/176,141 US6756769B2 (en) | 2002-06-20 | 2002-06-20 | Enabling circuit for avoiding negative voltage transients |
US10/738,058 US6906497B2 (en) | 2002-06-20 | 2003-12-17 | Enabling circuit for avoiding negative voltage transients |
US11/142,505 US7112943B2 (en) | 2002-06-20 | 2005-06-01 | Enabling circuit for avoiding negative voltage transients |
US11/535,173 US20070030714A1 (en) | 2002-06-20 | 2006-09-26 | Enabling Circuit for Avoiding Negative Voltage Transients |
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US11/142,505 Continuation US7112943B2 (en) | 2002-06-20 | 2005-06-01 | Enabling circuit for avoiding negative voltage transients |
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US10/738,058 Expired - Fee Related US6906497B2 (en) | 2002-06-20 | 2003-12-17 | Enabling circuit for avoiding negative voltage transients |
US11/142,505 Expired - Lifetime US7112943B2 (en) | 2002-06-20 | 2005-06-01 | Enabling circuit for avoiding negative voltage transients |
US11/535,173 Abandoned US20070030714A1 (en) | 2002-06-20 | 2006-09-26 | Enabling Circuit for Avoiding Negative Voltage Transients |
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US10/738,058 Expired - Fee Related US6906497B2 (en) | 2002-06-20 | 2003-12-17 | Enabling circuit for avoiding negative voltage transients |
US11/142,505 Expired - Lifetime US7112943B2 (en) | 2002-06-20 | 2005-06-01 | Enabling circuit for avoiding negative voltage transients |
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Families Citing this family (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6114814A (en) * | 1998-12-11 | 2000-09-05 | Monolithic Power Systems, Inc. | Apparatus for controlling a discharge lamp in a backlighted display |
US6949912B2 (en) * | 2002-06-20 | 2005-09-27 | 02Micro International Limited | Enabling circuit for avoiding negative voltage transients |
US6888339B1 (en) * | 2003-04-03 | 2005-05-03 | Lockheed Martin Corporation | Bus voltage control using gated fixed energy pulses |
US7193379B2 (en) * | 2003-10-20 | 2007-03-20 | Wabtec Holding Corp. | Electronic circuit arrangement for switching an electrical load in a fail safe manner |
CN1898997A (en) * | 2003-11-03 | 2007-01-17 | 美国芯源系统股份有限公司 | Driver for light source having integrated photosensitive elements for driver control |
US8618805B2 (en) * | 2004-03-25 | 2013-12-31 | 02Micro, Inc. | Battery pack with a battery protection circuit |
US7180268B2 (en) * | 2004-03-25 | 2007-02-20 | O2Micro International Limited | Circuits capable of trickle precharge and/or trickle discharge |
US7323829B2 (en) * | 2004-08-20 | 2008-01-29 | Monolithic Power Systems, Inc. | Minimizing bond wire power losses in integrated circuit full bridge CCFL drivers |
TWI318084B (en) | 2004-10-13 | 2009-12-01 | Monolithic Power Systems Inc | Methods and protection schemes for driving discharge lamps in large panel applications |
TWI345430B (en) * | 2005-01-19 | 2011-07-11 | Monolithic Power Systems Inc | Method and apparatus for dc to ac power conversion for driving discharge lamps |
US20060186937A1 (en) * | 2005-02-22 | 2006-08-24 | Rajendran Nair | Active noise regulator |
US7439685B2 (en) * | 2005-07-06 | 2008-10-21 | Monolithic Power Systems, Inc. | Current balancing technique with magnetic integration for fluorescent lamps |
US7420829B2 (en) | 2005-08-25 | 2008-09-02 | Monolithic Power Systems, Inc. | Hybrid control for discharge lamps |
US7291991B2 (en) * | 2005-10-13 | 2007-11-06 | Monolithic Power Systems, Inc. | Matrix inverter for driving multiple discharge lamps |
CN1953631A (en) * | 2005-10-17 | 2007-04-25 | 美国芯源系统股份有限公司 | A DC/AC power supply device for the backlight application of cold-cathode fluorescent lamp |
US7423384B2 (en) | 2005-11-08 | 2008-09-09 | Monolithic Power Systems, Inc. | Lamp voltage feedback system and method for open lamp protection and shorted lamp protection |
US7394203B2 (en) * | 2005-12-15 | 2008-07-01 | Monolithic Power Systems, Inc. | Method and system for open lamp protection |
US7619371B2 (en) | 2006-04-11 | 2009-11-17 | Monolithic Power Systems, Inc. | Inverter for driving backlight devices in a large LCD panel |
US7804254B2 (en) * | 2006-04-19 | 2010-09-28 | Monolithic Power Systems, Inc. | Method and circuit for short-circuit and over-current protection in a discharge lamp system |
US7420337B2 (en) * | 2006-05-31 | 2008-09-02 | Monolithic Power Systems, Inc. | System and method for open lamp protection |
CN101453818B (en) * | 2007-11-29 | 2014-03-19 | 杭州茂力半导体技术有限公司 | Discharge lamp circuit protection and regulation apparatus |
US10007286B2 (en) | 2011-01-24 | 2018-06-26 | Sunrise Micro Devices, Inc. | Switching regulator overload detector |
WO2012102933A2 (en) | 2011-01-24 | 2012-08-02 | Sunrise Micro Devices, Inc. | Detection of insufficient supplied power |
WO2014089314A1 (en) * | 2012-12-05 | 2014-06-12 | Remy Technologies, Llc | System, method, and circuitry to rectify an alternating current signal with mosfet half-bridge circuitry |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6580258B2 (en) * | 1993-03-23 | 2003-06-17 | Linear Technology Corporation | Control circuit and method for maintaining high efficiency over broad current ranges in a switching regulator circuit |
Family Cites Families (106)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5744915A (en) | 1978-03-20 | 1998-04-28 | Nilssen; Ole K. | Electronic ballast for instant-start lamps |
US5481160A (en) | 1978-03-20 | 1996-01-02 | Nilssen; Ole K. | Electronic ballast with FET bridge inverter |
US5422546A (en) | 1978-03-20 | 1995-06-06 | Nilssen; Ole K. | Dimmable parallel-resonant electric ballast |
US4476425A (en) | 1982-08-06 | 1984-10-09 | Alan Chernotsky | Battery charger |
US4535399A (en) | 1983-06-03 | 1985-08-13 | National Semiconductor Corporation | Regulated switched power circuit with resonant load |
US4541041A (en) | 1983-08-22 | 1985-09-10 | General Electric Company | Full load to no-load control for a voltage fed resonant inverter |
US4586119A (en) | 1984-04-16 | 1986-04-29 | Itt Corporation | Off-line switching mode power supply |
JPS613764A (en) | 1984-06-18 | 1986-01-09 | Fuji Photo Film Co Ltd | Semiconductor light source for image output device |
US4621313A (en) | 1985-06-28 | 1986-11-04 | Zenith Electronics Corporation | Soft-start capacitor discharge circuit |
JPH0724463B2 (en) | 1986-03-07 | 1995-03-15 | 株式会社東芝 | Power converter |
US4672528A (en) | 1986-05-27 | 1987-06-09 | General Electric Company | Resonant inverter with improved control |
US4864483A (en) | 1986-09-25 | 1989-09-05 | Wisconsin Alumni Research Foundation | Static power conversion method and apparatus having essentially zero switching losses and clamped voltage levels |
JPH07118915B2 (en) | 1987-01-30 | 1995-12-18 | 株式会社日立メデイコ | Resonant DC-DC converter |
US4727469A (en) | 1987-03-23 | 1988-02-23 | Reliance Comm/Tec Corporation | Control for a series resonant power converter |
US4833584A (en) | 1987-10-16 | 1989-05-23 | Wisconsin Alumni Research Foundation | Quasi-resonant current mode static power conversion method and apparatus |
EP0415923B2 (en) | 1987-10-29 | 2000-05-10 | Rifala Pty. Ltd. | High efficiency converter |
US4849682A (en) | 1987-10-30 | 1989-07-18 | Anton/Bauer, Inc. | Battery charging system |
US4912622A (en) | 1988-03-07 | 1990-03-27 | General Electric Company | Gate driver for a full-bridge lossless switching device |
US4860189A (en) | 1988-03-21 | 1989-08-22 | International Business Machines Corp. | Full bridge power converter circuit |
US4814962A (en) | 1988-05-27 | 1989-03-21 | American Telephone And Telegraph Company, At&T Bell Laboratories | Zero voltage switching half bridge resonant converter |
US4952849A (en) | 1988-07-15 | 1990-08-28 | North American Philips Corporation | Fluorescent lamp controllers |
US5019996A (en) | 1988-08-29 | 1991-05-28 | Advanced Micro Devices, Inc. | Programmable power supply level detection and initialization circuitry |
US5027263A (en) | 1988-09-16 | 1991-06-25 | Kyushu University | Switching power source means |
US4855888A (en) | 1988-10-19 | 1989-08-08 | Unisys Corporation | Constant frequency resonant power converter with zero voltage switching |
FR2649277B1 (en) | 1989-06-30 | 1996-05-31 | Thomson Csf | METHOD AND DEVICE FOR GRADING LIGHT FOR A FLUORESCENT LAMP FOR THE REAR LIGHTING OF A LIQUID CRYSTAL SCREEN |
US4935857A (en) | 1989-08-22 | 1990-06-19 | Sundstrand Corporation | Transistor conduction-angle control for a series-parallel resonant converter |
US5017800A (en) | 1989-09-29 | 1991-05-21 | Wisconsin Alumni Research Foundation | AC to DC to AC power conversion apparatus with few active switches and input and output control |
US5027264A (en) | 1989-09-29 | 1991-06-25 | Wisconsin Alumni Research Foundation | Power conversion apparatus for DC/DC conversion using dual active bridges |
US4953068A (en) | 1989-11-08 | 1990-08-28 | Unisys Corporation | Full bridge power converter with multiple zero voltage resonant transition switching |
US4992919A (en) | 1989-12-29 | 1991-02-12 | Lee Chu Quon | Parallel resonant converter with zero voltage switching |
US5198969A (en) | 1990-07-13 | 1993-03-30 | Design Automation, Inc. | Soft-switching full-bridge dc/dc converting |
US5231563A (en) | 1990-09-07 | 1993-07-27 | Itt Corporation | Square wave converter having an improved zero voltage switching operation |
US5132888A (en) | 1991-01-07 | 1992-07-21 | Unisys Corporation | Interleaved bridge converter |
US5291382A (en) | 1991-04-10 | 1994-03-01 | Lambda Electronics Inc. | Pulse width modulated DC/DC converter with reduced ripple current coponent stress and zero voltage switching capability |
US5132889A (en) | 1991-05-15 | 1992-07-21 | Ibm Corporation | Resonant-transition DC-to-DC converter |
US5208740A (en) | 1991-05-30 | 1993-05-04 | The Texas A & M University System | Inverse dual converter for high-power applications |
US5235501A (en) | 1991-07-19 | 1993-08-10 | The University Of Toledo | High efficiency voltage converter |
US5157592A (en) | 1991-10-15 | 1992-10-20 | International Business Machines Corporation | DC-DC converter with adaptive zero-voltage switching |
US5285372A (en) | 1991-10-23 | 1994-02-08 | Henkel Corporation | Power supply for an ozone generator with a bridge inverter |
US5384516A (en) | 1991-11-06 | 1995-01-24 | Hitachi, Ltd. | Information processing apparatus including a control circuit for controlling a liquid crystal display illumination based on whether illuminatio power is being supplied from an AC power source or from a battery |
US5448467A (en) | 1992-04-13 | 1995-09-05 | Ferreira; Jan A. | Electrical power converter circuit |
US5305191A (en) | 1992-04-20 | 1994-04-19 | At&T Bell Laboratories | Drive circuit for zero-voltage switching power converter with controlled power switch turn-on |
US5268830A (en) | 1992-04-20 | 1993-12-07 | At&T Bell Laboratories | Drive circuit for power switches of a zero-voltage switching power converter |
US5430641A (en) | 1992-04-27 | 1995-07-04 | Dell Usa, L.P. | Synchronously switching inverter and regulator |
US5355073A (en) | 1992-09-30 | 1994-10-11 | Compaq Computer Corporation | Battery pack sensor for an AC adapter |
US5412557A (en) | 1992-10-14 | 1995-05-02 | Electronic Power Conditioning, Inc. | Unipolar series resonant converter |
US5448155A (en) | 1992-10-23 | 1995-09-05 | International Power Devices, Inc. | Regulated power supply using multiple load sensing |
US5742148A (en) | 1992-11-24 | 1998-04-21 | Seiko Instruments Inc. | Charge/discharge control circuit and chargeable electric power source apparatus |
US5402329A (en) | 1992-12-09 | 1995-03-28 | Ernest H. Wittenbreder, Jr. | Zero voltage switching pulse width modulated power converters |
US5363020A (en) | 1993-02-05 | 1994-11-08 | Systems And Service International, Inc. | Electronic power controller |
US5420779A (en) | 1993-03-04 | 1995-05-30 | Dell Usa, L.P. | Inverter current load detection and disable circuit |
CA2096559C (en) | 1993-05-19 | 1999-03-02 | Daniel Pringle | Resonant unity power factor converter |
JP3006383B2 (en) | 1993-05-24 | 2000-02-07 | 日本電気株式会社 | Radio immunity test apparatus, radio immunity evaluation method, and radio wave irradiation unit |
KR960010713B1 (en) | 1993-08-17 | 1996-08-07 | 삼성전자 주식회사 | Electronic ballast |
US5418703A (en) | 1993-08-31 | 1995-05-23 | International Business Machines Corp. | DC-DC converter with reset control for enhanced zero-volt switching |
US5510974A (en) | 1993-12-28 | 1996-04-23 | Philips Electronics North America Corporation | High frequency push-pull converter with input power factor correction |
AUPM364394A0 (en) | 1994-02-01 | 1994-02-24 | Unisearch Limited | Improved power converter with soft switching |
DE69518572T2 (en) | 1994-04-29 | 2001-04-19 | Andre Bonnet | Static converter with controlled switch and control circuit |
US5917722A (en) | 1994-05-11 | 1999-06-29 | B&W Loudspeakers Ltd. | Controlled commutator circuit |
CH688952B5 (en) | 1994-05-26 | 1998-12-31 | Ebauchesfabrik Eta Ag | supply circuit for an electroluminescent sheet. |
CA2124370C (en) | 1994-05-26 | 1998-09-29 | Ivan Meszlenyi | Self oscillating dc to dc converter |
JP3027298B2 (en) | 1994-05-31 | 2000-03-27 | シャープ株式会社 | Liquid crystal display with backlight control function |
US5514921A (en) | 1994-06-27 | 1996-05-07 | General Electric Company | Lossless gate drivers for high-frequency PWM switching cells |
US5615093A (en) | 1994-08-05 | 1997-03-25 | Linfinity Microelectronics | Current synchronous zero voltage switching resonant topology |
KR0137917B1 (en) | 1994-10-28 | 1998-05-15 | 김광호 | Back-light driving circuit of liquid crystal display element |
JP2757810B2 (en) | 1995-03-08 | 1998-05-25 | 日本電気株式会社 | Power supply |
FR2733095B1 (en) | 1995-04-11 | 1997-05-09 | Alcatel Converters | DEVICE WITH VARIABLE INDUCTANCE AND USE THEREOF FOR PROVIDING A CURRENT SOURCE FOR A ZERO VOLTAGE SWITCHING CELL |
US5694007A (en) | 1995-04-19 | 1997-12-02 | Systems And Services International, Inc. | Discharge lamp lighting system for avoiding high in-rush current |
EP0741447A3 (en) | 1995-05-04 | 1997-04-16 | At & T Corp | Circuit and method for controlling a synchronous recifier converter |
KR0148053B1 (en) | 1995-05-12 | 1998-09-15 | 김광호 | Backlight driving control device and its driving control method of liquid crystal display elements |
US5638260A (en) | 1995-05-19 | 1997-06-10 | Electronic Measurements, Inc. | Parallel resonant capacitor charging power supply operating above the resonant frequency |
US5834889A (en) | 1995-09-22 | 1998-11-10 | Gl Displays, Inc. | Cold cathode fluorescent display |
JP2914251B2 (en) | 1995-10-31 | 1999-06-28 | 日本電気株式会社 | Inverter device |
KR0177873B1 (en) | 1995-12-02 | 1999-05-15 | 변승봉 | Soft switching full bridge dc-dc converter with high frequency of a circulating free current type |
US5875103A (en) | 1995-12-22 | 1999-02-23 | Electronic Measurements, Inc. | Full range soft-switching DC-DC converter |
WO1997024016A1 (en) | 1995-12-26 | 1997-07-03 | General Electric Company | Control and protection of dimmable electronic fluorescent lamp ballast with wide input voltage range and wide dimming range |
IT1289479B1 (en) | 1996-01-26 | 1998-10-15 | Schlafhorst & Co W | CIRCUITAL ARRANGEMENT OF VOLTAGE TRANSFORMATION FOR THE POWER SUPPLY OF A HIGH ELECTRIC USER |
US5684683A (en) | 1996-02-09 | 1997-11-04 | Wisconsin Alumni Research Foundation | DC-to-DC power conversion with high current output |
US5669238A (en) | 1996-03-26 | 1997-09-23 | Phillips Petroleum Company | Heat exchanger controls for low temperature fluids |
US5723970A (en) * | 1996-04-05 | 1998-03-03 | Linear Technology Corporation | Battery charging circuitry having supply current regulation |
US5781419A (en) | 1996-04-12 | 1998-07-14 | Soft Switching Technologies, Inc. | Soft switching DC-to-DC converter with coupled inductors |
US5619402A (en) | 1996-04-16 | 1997-04-08 | O2 Micro, Inc. | Higher-efficiency cold-cathode fluorescent lamp power supply |
US5784266A (en) | 1996-06-14 | 1998-07-21 | Virginia Power Technologies, Inc | Single magnetic low loss high frequency converter |
US5719474A (en) | 1996-06-14 | 1998-02-17 | Loral Corporation | Fluorescent lamps with current-mode driver control |
US5736842A (en) | 1996-07-11 | 1998-04-07 | Delta Electronics, Inc. | Technique for reducing rectifier reverse-recovery-related losses in high-voltage high power converters |
US5715155A (en) | 1996-10-28 | 1998-02-03 | Norax Canada Inc. | Resonant switching power supply circuit |
KR100199506B1 (en) | 1996-10-29 | 1999-06-15 | 윤문수 | A zero voltage/current switching circuit for reduced ripple current of the full-bridge dc/dc converter |
US5734261A (en) | 1996-11-05 | 1998-03-31 | National Instruments Corporation | Input protection circuit which includes optocoupler protection during over-voltage conditions |
US5781418A (en) | 1996-12-23 | 1998-07-14 | Philips Electronics North America Corporation | Switching scheme for power supply having a voltage-fed inverter |
US5894412A (en) | 1996-12-31 | 1999-04-13 | Compaq Computer Corp | System with open-loop DC-DC converter stage |
US5932976A (en) | 1997-01-14 | 1999-08-03 | Matsushita Electric Works R&D Laboratory, Inc. | Discharge lamp driving |
US5748457A (en) | 1997-01-24 | 1998-05-05 | Poon; Franki Ngai Kit | Family of zero voltage switching DC to DC converters |
US5774346A (en) | 1997-01-24 | 1998-06-30 | Poon; Franki Ngai Kit | Family of zero voltage switching DC to DC converters with coupled output inductor |
US5880940A (en) | 1997-02-05 | 1999-03-09 | Computer Products, Inc. | Low cost high efficiency power converter |
US6011360A (en) | 1997-02-13 | 2000-01-04 | Philips Electronics North America Corporation | High efficiency dimmable cold cathode fluorescent lamp ballast |
US5764494A (en) | 1997-03-13 | 1998-06-09 | Lockheed Martin Corporation | Saturable reactor and converter for use thereof |
US5930121A (en) | 1997-03-14 | 1999-07-27 | Linfinity Microelectronics | Direct drive backlight system |
US5923129A (en) | 1997-03-14 | 1999-07-13 | Linfinity Microelectronics | Apparatus and method for starting a fluorescent lamp |
JP3216572B2 (en) | 1997-05-27 | 2001-10-09 | 日本電気株式会社 | Drive circuit for piezoelectric transformer |
US5939830A (en) | 1997-12-24 | 1999-08-17 | Honeywell Inc. | Method and apparatus for dimming a lamp in a backlight of a liquid crystal display |
US6184660B1 (en) * | 1998-03-26 | 2001-02-06 | Micro International, Ltd. | High-side current-sensing smart battery charger |
US6114814A (en) | 1998-12-11 | 2000-09-05 | Monolithic Power Systems, Inc. | Apparatus for controlling a discharge lamp in a backlighted display |
US6127815A (en) * | 1999-03-01 | 2000-10-03 | Linear Technology Corp. | Circuit and method for reducing quiescent current in a switching regulator |
US6259615B1 (en) | 1999-07-22 | 2001-07-10 | O2 Micro International Limited | High-efficiency adaptive DC/AC converter |
US6330169B2 (en) * | 2000-02-25 | 2001-12-11 | Condor D.C. Power Supplies Inc. | Converter output regulation via channel resistance modulation of synchronous rectifiers |
SE519148C2 (en) * | 2000-04-07 | 2003-01-21 | Ericsson Telefon Ab L M | Method and device for regulating low voltages in flyback type DC converters with multiple outputs |
-
2002
- 2002-06-20 US US10/176,141 patent/US6756769B2/en not_active Expired - Fee Related
-
2003
- 2003-12-17 US US10/738,058 patent/US6906497B2/en not_active Expired - Fee Related
-
2005
- 2005-06-01 US US11/142,505 patent/US7112943B2/en not_active Expired - Lifetime
-
2006
- 2006-09-26 US US11/535,173 patent/US20070030714A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6580258B2 (en) * | 1993-03-23 | 2003-06-17 | Linear Technology Corporation | Control circuit and method for maintaining high efficiency over broad current ranges in a switching regulator circuit |
Also Published As
Publication number | Publication date |
---|---|
US20040130309A1 (en) | 2004-07-08 |
US20050218878A1 (en) | 2005-10-06 |
US6906497B2 (en) | 2005-06-14 |
US20030234633A1 (en) | 2003-12-25 |
US7112943B2 (en) | 2006-09-26 |
US6756769B2 (en) | 2004-06-29 |
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