WO2002001696A1

WO2002001696A1 - Device for powering an appliance

Info

Publication number: WO2002001696A1
Application number: PCT/FR2001/001883
Authority: WO
Inventors: Nicolas Berthou; Edouard Escobar; Maurice Cordier
Original assignee: Thales
Priority date: 2000-06-27
Filing date: 2001-06-15
Publication date: 2002-01-03
Also published as: FR2810810A1; FR2810810B1

Abstract

The invention concerns a device for powering an electronic appliance with electric power supply (1). The device comprises means for detecting (3) an interruption in the supply (1), means for storing (2) power tapped from the supply (1), processing means (4) powered by the storage means (2) receiving a signal derived from the detection means (3) and formatting current operations after receiving a signal representing an interruption in the supply (1), so as to enable the appliance to restart and current operations after exhaustion of the power present in the storage means (2) when the supply (1) is once more present after the interruption. The processing means (4) format the current operations after a transparency date (TT) intervening later than the date at which the supply voltage (1) takes on a reference value VOFF.

Description

POWER SUPPLY DEVICE FOR AN ELECTRONIC DEVICE

The invention relates to a power supply device for an electronic device. Such a device supplied by an external electrical network can be subjected to electrical supply cuts to the network harmful to its operation. In order to save its operation, the device may include means for storing energy taken from the network. To perform this function, for example, storage batteries or capacitors. The storage means replace the electrical network during the power cut to supply the device.

To increase the operating time of the device when it is no longer supplied only by the storage means, it is necessary to increase its capacity.

Furthermore, when the power supply network cuts out after the energy contained in the storage means has been used up, the electronic device may lose the progress of the programs it was carrying out and / or the data that 'he manipulated before exhaustion and restarting the device then requires an important time to restart the programs he was performing and / or acquire the lost data again.

The object of the invention is to increase the operating time of the appliance for given energy storage means as well as to reduce the restarting time of the appliance when the electrical supply by the network is again present. after the cut.

In certain fields, such as aeronautics, standards impose to keep an electronic device in operation for durations of power cuts planned in advance, for example 50 milliseconds or 200 milliseconds. To meet such standards, the invention makes it possible to reduce the capacities of the storage means and for example to replace a storage battery with a capacitor. Indeed, a storage battery makes it possible to store more energy per unit of volume than a capacitor, but it has the drawback of requiring periodic maintenance, in particular requiring the change of the battery at scheduled dates. If a storage battery is replaced by a capacitor, the invention therefore makes it possible to remove periodic maintenance from the device. More generally, the invention makes it possible to reduce the size of the storage means.

To achieve the aim stated above, the invention relates to a device for supplying an electronic device powered by a supply of electrical energy, characterized in that it comprises means for detecting a cut in the power supply, energy storage means taken from the power supply, processing means supplied by the storage means, receiving a signal from the detection means and shaping operations in progress after reception of a signal representative of 'A power cut, so as to allow a restart of the device and operations in progress after exhaustion of the energy present in the storage means when the power is again present after the cut.

The invention makes it possible to manage an abnormal operating mode such as for example when micro-cuts appear on the electrical supply.

The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment illustrated by the attached drawing in which: - Figure 1 shows a block diagram of an embodiment of the invention;

- Figure 2 shows in the form of a timing diagram different signals to better understand the operation of the block diagram; - Figure 3 shows an embodiment of the means for detecting a power cut.

In FIG. 1, the supply 1 of electrical energy sends energy to energy storage means 2. These energy storage means comprise for example an accumulator battery or advantageously one or more capacitors . In fact, capacitors are more reliable than accumulator batteries and do not require any particular maintenance. Furthermore, the electrical energy supply 1 is connected to means 3 for detecting a cut in the energy supply 1. The device also includes processing means 4 supplied with energy by the storage means 2. The processing means 4 receive information from the detection means 3. The processing means 4 are advantageously connected to storage means 5. Furthermore the processing means 4 can control connection means 6. These connection means 6 make it possible to connect or disconnect the power supply of secondary functions 7 to the device such as for example display means. When there is no interruption in the supply of electrical energy 1, the secondary functions 7 are connected to the storage means 2 and the processing means perform specific operations of the electronic device and not described here.

When the detection means 3 detect a cut in the energy supply 1, they send information representative of the cut to the processing means 4. When this information is received, the processing means disconnect the supply from the secondary functions 7 and format the specific operations, for example by storing them in the storage means 5 which are advantageously a non-volatile memory such as for example a hard disk or an electrically programmable memory.

It is also possible to directly supply the secondary functions 7 by the power supply 1 with electrical energy without passing through the storage means. This variant makes it possible to dispense with connection means 6. In fact, as soon as a power outage occurs, the secondary functions are no longer supplied with electrical energy. On the other hand, this variant does not make it possible to delay the disconnection of the secondary functions thus ensuring a period of transparency which will be described later using the timing diagram 2c.

The electronic device can of course comprise several types of secondary functions, some supplied directly by the power supply 1 and others via the storage means 2 and connection means 6.

Figure 2 shows three timing diagrams 2a, 2b and 2c. These three chronograms have the same time scale. The first timing diagram 2a represents an example of evolution over time of the voltage of the electrical energy supply 1. At first the supply voltage is at a value Vcc allowing to operate normally the electronic device. Then a cut in the power supply 1 appears and the supply voltage drops following a slope to a low value which is prolonged. Subsequently at the end of the cut, the supply voltage rises, also following a slope until the value V _C c is again reached.

Between the low value and the value V _C c. of the voltage, there are shown on the timing diagram 2a two voltages, one V _O FF and the other V _O N greater than VOFF- The usefulness of these two voltages V ₀ N and VOFF will be described later. The timing diagram 2b describes the output signal from the detection means 3. Firstly, this signal is in state 1, this state is representative of the absence of interruption in the supply 1 of electrical energy. Then at the moment when the voltage of the electric power supply 1 drops until reaching the voltage V ₀ FF or advantageously shortly after, on the detection date To, the signal represented on the timing diagram 2b takes a zero value representative of a cut in the supply of electrical energy 1.

Advantageously, the date of detection T _D occurs later than the moment when the supply voltage 1 of the device decreases when reaching the voltage VOFF- This time shift makes it possible to avoid any untimely detections of a power cut of very short duration, for example of the order of a few microseconds.

The signal represented on the timing diagram 2b remains in the zero state as long as the supply voltage does not rise to a value greater than the voltage VON-

The timing diagram 2c represents the power consumed by the electronic device during the interruption of the supply 1 of electrical energy. Initially the device operates normally and the power consumed is said to be nominal, it is noted PN- Then when the cut-off appears, that is to say that the voltage Vcc drops below the voltage V _O FF, the power consumed advantageously remains equal to the power PN until the transparency date T _τ . Advantageously, the transparency date T _τ occurs later than the detection date TD, thus ensuring a period during which the operation of the device is not altered. Between the dates TD and TT, the processing means 4 ensure, in addition to their normal functions for processing specific operations of the device, a time counting up to the date of transparency TT. When this is reached, the processing means format the specific operations in progress. For example, they store in the non-volatile memory 5 all the information necessary for the subsequent resumption of these operations.

Also after the date TT, the processing means 4 disconnect the secondary functions 7 of the apparatus, thereby reducing the power consumed up to a reduced power PR, less than the nominal power PN. Then the device consumes the energy contained in the storage means 2 by dissipating a power PR as long as the storage means 2 allow it.

Then, if the cut is prolonged, the device stops and no longer consumes energy. It is understood that if the power cut 1 ends before the device has exhausted the energy contained in the storage means 2, the device will resume normal operation at power P before s' Stop.

FIG. 3 represents an exemplary embodiment of the means 3 for detecting a cut in the power supply 1. The voltage of the supply 1 is connected to the detection means at point 10. This supply voltage first undergoes a filtering step represented in box 11. Next to box 12 are determined the detection thresholds V _O N and VOFF- The signal from frame 12 is then filtered in frame 13 and then shaped in frame 14. At the outlet of frame 14, the frame 15 shown makes it possible to galvanically isolate the output signal from the detection means with respect to the means of processing 4. The frame 15 is followed by means 16 for shaping the signal representative of the interruption of the supply 1, signal supplied to the processing means 4.

More specifically, the point 10 is connected to a ground 20 via two resistors 21 and 22, both forming a voltage divider. Resistor 21 being connected to point 10 and resistor 22 to ground 20. The common point of these two resistors is connected to ground 20 by means of a capacitor 23. The common point of the two resistors 21 and 22 is also connected to the input of frame 12 by via a resistor 24. The capacitor 23 and the resistor 22 both form a time constant making it possible to define the time TD. At the input of the frame 12, the resistor 24 is connected to the inverting input of an operational amplifier 25. The non-inverting input of the operational amplifier 25 is connected to a reference voltage 40, via d a resistor 26. The output of the operational amplifier 25 is connected to the anode of a diode 27. The cathode of this diode 27 is connected to the non-inverting input of the operational amplifier 25 via a resistor 28. The electronic components grouped in frame 12 give an example of an embodiment of the comparison of the supply voltage 1 with the two voltages V _O FF and V ₀ N. When the supply voltage 1 has a value Vcc, the operational amplifier 25 is saturated and its output voltage is close to its negative supply voltage. The diode 27 does not conduct and no current flows through the resistors 26 and 28. Thus the voltage of the non-inverting input of the operational amplifier 25 is equal to the reference voltage 40. Then, when the supply voltage 1 decreases, and as the potential of the inverting input decreases until it becomes lower than the potential of the non-inverting input, then the output voltage of the operational amplifier 25 rapidly increases substantially to its positive supply voltage .

The potential of the reference voltage 40 is fixed in such a way that the rapid growth of the output voltage of the operational amplifier occurs when the supply voltage 1 decreases by taking the value VOFF-

As a result, the diode 27 becomes conductive and the resistors 26 and 28 then behave as a voltage divider between the strongly positive output voltage of the operational amplifier 25 and the reference voltage 40. Thus the potential of the input not reversing of the operational amplifier 25 goes up to form a new threshold defined as a function of VON- This threshold is that which must be exceeded by the potential of the inverting input of the operational amplifier 25 so that the output voltage of the operational amplifier 25 decreases again. The values of resistors 26 and 28 are defined according to the desired VON value.

The output voltage of the operational amplifier 25 can be compared to binary information in the form of a voltage close to one of the two positive and negative supply voltages of the operational amplifier 25.

The electronic components grouped together in frame 25 make it possible to carry out detection of a power cut 1 with hysteresis, that is to say that the information relating to the start of the cut occurs for a supply voltage 1 equal to VOFF, that the information relating to the end of the cut-off occurs for a supply voltage 1 equal to V _O N and finally that the values of V ₀ N and V _O FF are different.

The output of the operational amplifier 25 is connected to the frame 13 to ground 20 via a resistor 29 connected in series with a capacitor 30. The common point of the resistor 28 and the capacitor 29 are connected to the non-inverting input of an operational amplifier 31 located in frame 14. The inverting input of the operational amplifier 31 is connected to the common point of a resistor 32 and the cathode of a Zener diode 33. The anode of the Zener diode is connected to earth 20.

Resistor 31 is also connected to a reference voltage. The inverting input of the operational amplifier 30 thus remains at a stable voltage. The output of the operational amplifier 30 is saturated either at its positive supply voltage or at its negative supply voltage. This makes it possible to format the detection signal. The output of the operational amplifier 30 is connected to isolation means shown in frame 15. These isolation means comprise for example a light-emitting diode 34 whose radiation controls the base of a phototransistor 35. The collector of the phototransistor 35 forms the output of the frame 15 which is connected to the shaping means, for example a non-cell 16. The output of the non-cell 16 delivers the signal representative of the power cut 1 to the processing means 4. The phototransistor emitter 35 is for example connected to a ground 36 different from ground 20.

Claims

1. Device for supplying an electronic device supplied with a power supply (1) with electrical energy, characterized in that it comprises means (3) for detecting a power cut (1), means storage (2) of energy taken from the power supply (1), processing means (4) supplied by the storage means (2), receiving a signal from the detection means (3) and shaping operations in progress after reception of a signal representative of a power cut (1), so as to allow a restart of the apparatus and operations in progress after exhaustion of the energy present in the storage means (2) when the supply (1) is again present after the cut and in that the processing means (4) format the operations in progress after a transparency date (TT) occurring later than the date at wherein the supply voltage (1) takes a value V _O FF r ference.

2. Device according to claim 1, characterized in that the storage means (2) comprise one or more capacitors.

3. Device according to one of the preceding claims, characterized in that it comprises non-volatile storage means (5) in which the processing means (4) write, after reception of the signal representative of a cut-off of the power supply (1), parameters relating to the operations in progress, the parameters allowing, when the device is restarted, the continuation of the operations in progress.

4. Device according to claim 3, characterized in that the processing means (4) enter the parameters relating to the operations in progress, after a transparency date (TT) occurring later than the date on which the voltage of the power supply (1) takes a reference VOFF value.

5. Device according to one of the preceding claims, characterized in that it comprises connection means. (6) of the power supply (1) of secondary functions (7) of the device, in that the connection means (6) are controlled by the processing means (4) and in that the connection means ( 6) disconnect the power supply from the secondary functions (7) when a power failure (1) is detected.

6. Device according to claim 5, characterized in that the connection means (6) disconnect the supply of the secondary functions (7) after a transparency date (TT) occurring later than the date on which the voltage of the power supply (1) takes a reference value V _O FF.

7. Device according to one of the preceding claims, characterized in that the detection means (3) deliver to the processing means (4) a signal representative of a power cut on the date of detection (TD), occurring later than the date on which the supply voltage (1) takes a reference value V _O FF.

8. Device according to one of claims 2, 4 or 6, characterized in that the transparency date (TT) occurs later than the detection date (T _D ).

9. Device according to one of the preceding claims, characterized in that the detection means (3) detect a cut with hysteresis.