Electronic system comprising a power supply module and an electronic device

Abstract

The invention relates to an electronic system comprising a power supply module (5) configured to supply power to an electronic device (3), the electronic device (3) comprising at least one light source (9), a rechargeable battery (13), and a switching module (12) configured such that - in a first configuration, the rechargeable battery (13) is electrically coupled to the power supply module via the switching module (12) and the light source (9) is not supplied with power, - in a second configuration, the rechargeable battery (13) is disconnected from the power supply module (5) and electrically coupled to the light source (9) via the switching module so as to supply it with power, the system being characterized in that the switching module (12) is a bidirectional chopper the first configuration of which is a series chopper configuration and the second configuration of which is a parallel chopper configuration.

Description

Description Title of the invention: Electronic system comprising a power supply module and an electronic device technical field

[0001] The present invention relates to the technical field of electronics, and in particular to the management of the electrical consumption of electronic devices, especially imaging devices.

[0002] The invention relates particularly to an electronic system comprising a power supply module configured to power an electronic device. Technological background

[0003] In the field described above, it is known that the current consumption of electronic devices can vary. In particular, the temporary activation of certain components of the device can generate a significant power surge.

[0004] For example, some imaging devices are configured to capture three-dimensional images using a laser diode that emits pulsed light, such as infrared. Activating this light source generates regular current spikes, which can cause problems.

[0005] For example, in the case of an architecture in which the device control data and the supply current pass through the same coaxial cable, the current spikes passing through the cable generate electromagnetic noise that can disrupt the transmission of commands, and therefore the proper functioning of the system.

[0006] Furthermore, some electronic control units are not capable of supplying sufficiently high current values, so it may be necessary to use a more powerful, and therefore more expensive, electronic control unit simply to ensure the operation of said components, for example, simply to ensure the operation of the laser diode in the in the case of an imaging device. Thus, for all other operations of the device, the electronic unit is, from the point of view of its power supply, oversized. Summary of the invention

[0007] The invention provides a solution to the aforementioned problem by means of a system comprising an electronic control unit powering an electronic device.

[0008] According to one aspect of the invention, an electronic system is proposed comprising a power supply module configured to power an electronic device, the electronic device comprising at least one light source, a battery, and a switching module configured so that - In a first configuration, the battery is electrically coupled to the power supply module via the switching module and the diode is not powered, - in a second configuration, the accumulator is disconnected from the power supply module and electrically coupled to the light source via the switching module in order to power it, the switching module being a bidirectional chopper whose first configuration is a series chopper configuration and the second configuration is a parallel chopper configuration.

[0009] Thus, thanks to the invention, the light source, which requires a significant current to activate, is not powered directly by the power supply module but by the battery, which charges when the light source is inactive or switched off. This allows the device to be powered by a power supply module with a lower capacity. Furthermore, avoiding excessive current in the system prevents electromagnetic interference problems.

[0010] According to one embodiment, the system includes an electronic control unit comprising the power supply module and connected to the electronic device by a coaxial cable; the electronic control unit being configured to control and power the electronic device via the coaxial cable.

[0011] According to one embodiment, the electronic device is an optical measuring device or an imaging device.

[0012] According to one embodiment, the light source is a laser diode.

[0013] According to one embodiment, the light source is a vertical cavity laser diode emitting from the surface.

[0014] According to one embodiment, the switching module is configured to switch from the first configuration to the second configuration when the voltage across the battery reaches a first predetermined value.

[0015] According to one embodiment, the switching module is configured to switch from the second configuration to the first configuration when the voltage across the battery reaches a second predetermined value.

[0016] According to one embodiment, the system includes an optical sensor.

[0017] According to one embodiment, the light source is configured to generate periodic light pulses.

[0018] According to one embodiment, the switching module comprises a first switch coupled between the electronic control unit and a first terminal of the light source, and / or a second switch coupled between a second terminal of the light source and ground, and / or a capacitor coupled between the first terminal of the light source and ground, and / or a resistor coupled between the first terminal of the light source and an inductor whose first terminal is coupled to the resistor and whose second terminal is coupled to a third switch, and / or a fourth switch whose first terminal is coupled to the second terminal of the inductor and ground, the accumulator being coupled between a second terminal of the fourth switch and ground, the system being configured to be in the first configuration when the first switch is closed and the second switch is open, and in the second configuration when the first switch is open and the second switch is closed.

[0019] Of course, the different features, variants and embodiments of the invention can be combined with each other in various ways as long as they are not incompatible or mutually exclusive. Brief description of the figures

[0020] Furthermore, various other features of the invention become apparent from the attached description made with reference to the drawings which illustrate non-limiting embodiments of the invention and where:

[0021] [Fig. 1] is a schematic view of an electronic system according to one embodiment of the invention,

[0022] [Fig. 2] is an electrical diagram of an electronic device from the system in Figure 1,

[0023] [Fig. 3] is a timing diagram illustrating the operation of the electronic device in Figure 2.

[0024] It should be noted that in these figures the structural and / or functional elements common to the different variants may have the same references.

[0025] An electronic system as schematically represented in Figure 1 is designated as a whole by the reference symbol 1.

[0026] For example, system 1 is an optical sensor, for example, an imaging system configured to perform image captures, including three-dimensional images or simple depth measurements, notably by implementing so-called "time-of-flight" measurements. To this end, system 1 includes a light source 9 configured to generate light pulses, and an optical sensor 8 configured to detect said light pulses, for example after reflection from elements of the system's environment.

[0027] For example, electronic system 1 can be embedded in a motor vehicle and be part of a driver assistance system.

[0028] The electronic system 1 here comprises an electronic control unit 2 (also called ECU, for "Electronic Control Unit", according to Anglo-Saxon terminology) and an electronic device 3. The electronic control unit is configured to power and control the electronic device 3, which includes the sensor 8 and the light source 9. The same coaxial cable 4 allows the transmission of a power supply current 12 and computer control instructions from the electronic control unit 2 to the electronic device 3.

[0029] The electronic control unit 2 here includes a power supply module 5 configured to provide the supply current 12, and a computer processing module configured to generate the computer control instructions.

[0030] A serializer circuit 6 is coupled here between the computer processing module 23 and the coaxial cable 4 and is configured to adapt the computer instructions to the transfer on the coaxial cable 4.

[0031] In order to limit interference between the supply current 12 and the computer instructions, the electronic control unit 2 also includes a filter 7 coupled between the power supply module 5 and the coaxial cable 4. For example here, the filter is of the PoC type ("Power Over Coax", according to Anglo-Saxon terminology) and allows the continuous supply signal and the transmitted data to be combined.

[0032] The electronic device 3 here includes a power management integrated circuit 10 (PMIC, for "Power Management Integrated Circuit", according to Anglo-Saxon terminology), coupled between the coaxial cable 4 and the sensor 8, which is configured to perform operations on the supply voltage of the sensor 8, for example power regulation and sequencing operations.

[0033] A deserializer circuit 11 is coupled between the coaxial cable 4 and the sensor 8 and is configured to reshape the computer instructions modified by the serializer circuit 6.

[0034] The optical sensor 8 is here a photodiode or an array of photodiodes, and the light source 9 is here a laser diode, for example a cavity laser diode vertical emitting by the surface (VCSEL, "Vertical Cavity Surface-Emitting Laser", according to the Anglo-Saxon terminology).

[0035] A second filter 71 allows the continuous power supply signal and the received data to be separated.

[0036] The electronic device 3 comprises a switching module 12 coupled to the light source 9 and a battery 13, here a first capacitor. The switching module is either in a first configuration or a second configuration. Depending on the configuration of the switching module 12, the diode 9 will be powered or not.

[0037] In the first configuration, the switching module 12 is configured to couple the accumulator 13 to the electronic control unit 2 so that it charges. In this first configuration, the light source 9 is disconnected from the electronic control unit 2 and the capacitor 13 and is not powered. It therefore does not emit a light signal.

[0038] In its second configuration, the accumulator 13 is disconnected from the electronic control unit 2 and is electrically coupled to the light source 9. In this second configuration, the diode 9 is powered by the accumulator 13 and therefore emits a light signal.

[0039] Preferably, the duration for which the switching module 12 is in its first configuration is significantly greater than the duration for which the switching module is in its second configuration 12, for example at least three times greater, so that the signal emitted by the diode is pulsed.

[0040] Thus, supplying the light source 9 with the accumulator 13 avoids the generation of a peak in the supply current 12 (corresponding to the light pulse of the light source) in the coaxial cable, since the diode is never directly supplied by the electronic control unit, but by the accumulator 13.

[0041] According to some embodiments, the switching module 12 can perform operations on the voltage across the diode and on the voltage across the first capacitor 13, in particular voltage step-up or voltage step-down operations, as will be seen below.

[0042] Figure 2 is an electrical diagram partially illustrating the electronic device 2, and more specifically, the switching module in this embodiment. For the sake of simplicity, the electronic control unit 2 is schematically represented as a single block. The voltage and current supplied by the control module 2 to the switching module 13 are denoted V2 and V12, respectively.

[0043] A reverse current protection diode 14, or reverse current protection diode, is here coupled between the electronic control unit 2 and the switching module 12 in order to prevent, during the operation of the switching module, a reverse current from damaging the electronic control unit 2.

[0044] The switching module 12 includes a first switch 15, coupled between the cathode of the anti-reverse diode 14 and the anode of the diode 9. A second switch 16 is coupled between the cathode of the diode 9 and ground.

[0045] The switching module 12 further includes a second capacitor 17, one terminal of which is connected to the cathode of diode 9 and the other terminal of which is connected to ground. A resistor 18 is connected in series with an inductor 19 between the first terminal of the second capacitor 17 and the first terminal of a third switch 20, the other terminal of which is connected to ground.

[0046] A fourth switch 21 is coupled between the first terminal of the third switch and a first terminal of the first capacitor 13. A second terminal of the first capacitor 13 is coupled to ground.

[0047] In this example, each of the switches 14, 15, 20, and 21 contains a transistor or a set of transistors, for example, one or more metal-oxide-gate field-effect transistors, or MOSFETs (Metal-Oxide Field-Effect Transistors). The switches are controlled by the computer processing module 23.

[0048] In the configuration described here, the switching module 12 is a synchronous bidirectional chopper which, in the first configuration, has a series chopper configuration ("Buck driver", according to Anglo-Saxon terminology) and, in the second configuration, has a parallel chopper configuration ("Boost driver", according to Anglo-Saxon terminology).

[0049] A dotted outline with the numerical reference 22 delimits the portion of the switching module which, in each configuration, forms a synchronous chopper (series or parallel). The complementary opening and closing of the two switches 15 and 16 allows switching from the first configuration to the second configuration. Thus, the chopper 22 and the switches 14 and 15 (controlled by the computer processing module) form the bidirectional chopper.

[0050] In particular, in the first configuration, the first switch 15 is closed (the corresponding MOSFET transistor(s) are conducting) and the second switch 16 is open (the MOSFET transistor(s) are blocked). The chopper 22 behaves as a series chopper whose input voltage is V2, and whose output voltage is V13 across the first capacitor 13.

[0051] In the second configuration, the first switch 15 is open (the corresponding MOSFET transistor(s) are off) and the second switch 16 is closed (the MOSFET transistor(s) are on). The chopper 22 behaves as a parallel chopper whose input voltage is the voltage V13 across the first capacitor, and whose output voltage is the voltage V9 across diode 9.

[0052] In either of the first and second configurations, the third switch 20 and the fourth switch 21 are configured to switch in a complementary manner.

[0053] The operation of the switching module 12 will be described below in relation to the timing diagram in Figure 3.

[0054] The first four lines of the timing diagram relate to the states of switches 15, 16, 20, and 21 (or to the gate voltages of the corresponding transistors). On these lines, a high level corresponds to a closed, or conducting, state of the corresponding switch, and a low, or zero, level corresponds to an open, or blocked, state of the corresponding switch.

[0055] The fifth line of the timing diagram illustrates the evolution of the voltage V13 across the first capacitor 13. The sixth line of the timing diagram illustrates the evolution of the supply current 12 and the seventh and last line illustrates the evolution of the current 19 through the diode 9.

[0056] Two successive periods, P1 and P2, of the operating switching module are illustrated here. In each period, the switching module is first in the first configuration, then in the second configuration. Initially, all switches are either open or blocked.

[0057] At a first instant tl, the switching module transitions to the first configuration. The first switch 15 becomes conducting and the second switch remains blocked. The third and fourth switches switch in a complementary manner. For example, the duty cycle al of the third switch 20 in the first configuration is determined here according to the following formula:

[0058] [Math. 1]

[0059] al = (713 - V2) / V13

[0060] The first capacitor 13 charges and the voltage V13 across it gradually increases. The current 12 reaches an initial value. Due to the series chopper configuration of the switching module 13, the voltage V13 across the capacitor is greater than the voltage between the anode of diode 9 and ground.

[0061] When the voltage V13 reaches a predetermined voltage threshold, here at a second instant t2, all the switches go into the blocked state until a third instant t3. Between instants t2 and t3, the switching module is in a transient configuration, that is to say, it is neither in the first configuration, nor in the second configuration. During this period, the voltage V13 across the first capacitor 13 remains substantially constant and no current flows in the switching module 12. Such a transient period is advantageous in order to prevent the first switch 15 and the second switch 16 from being simultaneously conducting.

[0062] At time t3, the switching module 12 transitions to the second configuration. The second switch 16 becomes conducting, and the first switch 15 remains blocked. The third switch 20 and the fourth switch 21 switch in a complementary manner. For example, the duty cycle of the third switch 20 in the second configuration is determined here according to the following formula:

[0063] [Math. 2]

[0064] al = V9 / V13,

[0065] The first capacitor 13 discharges and supplies the diode 9 which is traversed by the current 19. Due to the parallel chopper configuration of the switching module 12, the voltage V13 across the capacitor is greater than the voltage across the diode 9.

[0066] When the voltage V13 across the first capacitor 13 reaches a second predetermined threshold, here at a fourth instant t4, the switching module 12 returns to the transient configuration and all switches either pass through or remain in a blocked state.

[0067] The second period P2 unfolds in a manner similar to the unfolding of the first period.

[0068] The embodiments described here in connection with Figures 1 to 3 are by no means limiting. In particular, although a connection between the electronic control unit 2 and the electronic device 3 via a coaxial cable has been described here, the invention is compatible with communication and power supply via separate lines.

[0069] Furthermore, the implementation methods of switches in the form of one or more MOSFET transistors described here are by no means limiting, and it would be possible to consider implementing the switches in any other way.

[0070] Various other modifications may be made to the invention within the scope of the attached claims.

Claims

Demands 1. An electronic system (1) comprising a power supply module (5) and an electronic device (3), said power supply module (5) being configured to power an electronic device (3), the electronic device (3) comprising at least one light source (9), a battery (13) and a switching module (12) and being configured so that - in a first configuration, the accumulator (13) is electrically coupled to the power supply module (5) via the switching module (12) and the light source (9) is not powered, - in a second configuration, the accumulator (13) is disconnected from the power supply module (5) and electrically coupled to the light source (9) via the switching module (12) so as to power it, the system (1) being characterized in that the switching module (12) is a bidirectional chopper whose first configuration is a series chopper configuration and the second configuration is a parallel chopper configuration.

2. Electronic system (1) according to claim 1, comprising an electronic control unit (2) which includes the power supply module (5) and which is connected to the electronic device (3) by a coaxial cable (4), the electronic control unit (2) being configured to control and power the electronic device (3) via the coaxial cable (4).

3. Electronic system (1) according to claim 1 or 2, the system (1) being an optical measuring device or an imaging device.

4. Electronic system (1) according to any one of claims 1 to 3, wherein the light source (9) is a laser diode.

5. Electronic system (1) according to claim 4, wherein the light source (9) is a vertical cavity laser diode emitting from the surface.

6. Electronic system (1) according to any one of claims 1 to 5, wherein the switching module (12) is configured to switch from the first configuration to the second configuration when the voltage across the accumulator (13) reaches a first predetermined value.

7. Electronic system (1) according to any one of claims 1 to 6, wherein the switching module (12) is configured to switch from the second configuration to the first configuration when the voltage across the accumulator (13) reaches a second predetermined value.

8. Electronic system (1) according to any one of claims 4 to 7 taken in their dependence on claim 3, comprising an optical sensor (8).

9. Electronic system (1) according to any one of claims 1 to 8, wherein the light source (9) is configured to generate periodic light pulses.

10. Electronic system (1) according to any one of claims 1 to 8, wherein the switching module (12) comprises a first switch (15) coupled between the power supply module (5) and a first terminal of the light source (9), a second switch (16) coupled between a second terminal of the light source (9) and ground, a capacitor (17) coupled between the first terminal of the light source (9) and ground, a resistor (18) coupled between the first terminal of the light source (9) and a coil (19) having a first terminal coupled to the resistor (18) and a second terminal coupled to a third switch (21), a fourth switch having a first terminal coupled to the second terminal of the coil (18) and ground, the accumulator (13) being coupled between a second terminal of the fourth switch (21) and ground,the system being configured to be in the first configuration when the first switch (15) is closed and the second switch (16) is open, and in the second configuration when the first switch (15) is open and the second switch (16) is closed.

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