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EP-4740701-A1 - DEVICE AND METHOD FOR CONTROLLING THE POWER SUPPLY OF LIGHT SOURCES FOR A MOTOR VEHICLE

EP4740701A1EP 4740701 A1EP4740701 A1EP 4740701A1EP-4740701-A1

Abstract

The invention relates to luminous systems for motor vehicles. The invention provides a device and method that make it possible to increase the efficiency of a converter depending on variations in its load. This is made possible through use of a synchronous-converter circuit rather than an asynchronous converter as is commonly used for automotive lighting applications.

Inventors

  • KRICK, SEBASTIAN

Assignees

  • Valeo Vision

Dates

Publication Date
20260513
Application Date
20240704

Claims (11)

  1. [Claim 1] Device for controlling the electrical power supply (100, 200, 300) of a plurality of light sources, subassemblies of which are configured to selectively perform different lighting functions of a motor vehicle, the control device comprising a converter circuit (110, 210, 310) controlled by a control unit (120, 220, 320), characterized in that the converter circuit (110, 210, 310) is a synchronous switching converter circuit comprising two transistors, in that the control unit (120, 220, 320) is configured to provide a switching signal (122, 222, 322) to the converter circuit, and in that the frequency of said switching signal is dependent on an average intensity of electrical charging current to be provided to the light sources, an indication of which is provided by an input signal (102, 202, 302) and which depends on the lighting functions to be performed.
  2. [Claim 2] Control device (100, 200, 300) according to the preceding claim, characterized in that the indication of an average intensity of electric charging current to be supplied to the light sources comprises an indication of a subset of light sources to be supplied.
  3. [Claim 3] Control device (200) according to one of the preceding claims, characterized in that it comprises a memory element (230) in which a predetermined switching frequency is recorded (232) for each average intensity of electric load current to be supplied to the light sources, and in that the control unit (220) is configured to read the switching frequency which corresponds to the average intensity of electric load current indicated by the input signal (202) in the memory element (230), in order to produce a switching signal (222) having a corresponding frequency.
  4. [Claim 4] Control device (100, 200, 300) according to one of the preceding claims, characterized in that the converter circuit (110, 210, 310) is operated in forced continuous conduction mode.
  5. [Claim s] Control device (100, 200, 300) according to one of the preceding claims, characterized in that the converter circuit synchronous (110, 210, 310) includes metal-oxide-semiconductor, MOS, transistors.
  6. [Claim s] Driving device (100, 200, 300) according to one of claims 1 to 4, characterized in that the synchronous converter circuit (110, 210, 310) comprises Gallium nitride, GaN, type transistors.
  7. [Claim 7] Control device (300) according to one of the preceding claims, characterized in that the control unit (320) comprises a memory element and is configured to determine the switching frequency as a function of the indication (302) of at least one light function to be performed, by selecting a switching frequency value from among several predetermined switching frequency values stored in the memory element.
  8. [Claim 8] Control device (300) according to one of claims 1 to 6, characterized in that the control unit (320) is configured to adapt the switching frequency as a function of an indication of the temperature (304) of at least one light source to be supplied.
  9. [Claim 9] Control device (300) according to claim 8, characterized in that it comprises a memory element (330) in which are recorded (332), for predetermined temperature indications (T1, T2), a predetermined switching frequency for each average intensity of electric charging current to be supplied to the light sources, and in that the control unit (320) is configured to read the switching frequency which corresponds to the indicated temperature (304) and to the at least one light function to be carried out indicated by the input signal (302) in the memory element (330), in order to produce a switching signal (322) having a corresponding frequency.
  10. [Claim 10] Control device (100, 200, 300) according to one of the preceding claims, characterized in that the synchronous converter circuit (110, 210, 310) is a “boost” voltage booster circuit.
  11. [Claim 11] Method for limiting losses in a power supply control device (100, 200, 300) of a plurality of light functions of a motor vehicle according to one of claims 1 to 9, characterized in that the method comprises the steps: a) receiving, by the control unit (120, 230, 320), an input signal (102, 202, 302) comprising an indication of an average intensity of electric charging current to be supplied to the light sources (10, 20, 30); b) generating, by the control unit (120, 220, 320), a switching signal (122, 222, 322) having a frequency which depends on the average intensity of electric charging current indicated by the input signal (102, 202, 302); c) controlling, by the control unit (120, 220, 320), the synchronous converter circuit (110, 210, 310) of said control device, by means of said switching signal (122, 222, 322).

Description

Description Title: DEVICE AND METHOD FOR CONTROLLING THE ELECTRICAL POWER SUPPLY OF LIGHT SOURCES FOR A MOTOR VEHICLE [0001] This invention relates to the field of motor vehicle lighting, and in particular it relates to such systems using light sources with electroluminescent semiconductor elements powered by means of a converter circuit. [0002] A light-emitting diode, LED, is a semiconductor electronic component capable of emitting light of a predetermined wavelength when an electrical voltage at least equal to a threshold value is applied to its terminals. Beyond this threshold value called forward voltage, the intensity of the luminous flux emitted by an LED generally increases proportionally with the average intensity of the supply electric current. Their small size and low electricity consumption make LED components interesting in the field of light modules for motor vehicles. LED-type light sources can, for example, be used to produce distinctive optical signatures by placing the components along predetermined contours. The limited space available for the use of such light sources, their potentially high number to produce interesting effects, as well as the limited electrical energy available in a closed system such as a motor vehicle, further accentuates power losses, which result in undesirable localized heating. [0003] It is known to power light-emitting diodes that perform a plurality of lighting functions of a motor vehicle by means of voltage-stepping and/or step-up converter circuits. Thus, an input voltage, generally provided by an internal battery of the motor vehicle, is converted into a charging voltage suitable for powering the required light sources. [0004] In particular, a voltage boost converter (for example of the BOOST type) is often associated with at least one step-down converter (for example of the BUCK type) for example as described in FIG. 6. A first voltage Vout is generated there by a voltage boost circuit 610 to power modules light sources 6010 and 6020, each comprising a voltage step-down circuit (6011, 6021) and at least one light source (6012, 6022). [0005] The average output voltage of the voltage-boosting converter circuit corresponds to the input voltage requirements of the voltage-stepping circuits, and generally varies little or not at all. Therefore, a change in the power requirement almost always corresponds to a change in current. The "load", i.e. the power requirement, therefore corresponds to an average current intensity. [0006] It has been proposed in patent document EP 3503684 B1 to increase the efficiency of a converter as a function of variations in the input voltage supplied to the converter. While it is desirable to limit losses in such a system, it turns out in practice that the input voltage supplied by a battery of the motor vehicle generally remains constant and exhibits only minimal fluctuations. The impact of this solution on the efficiency of the system therefore remains limited. [0007] The invention aims to overcome at least one of the problems posed by the prior art. More specifically, the invention aims to propose a device and a method which make it possible to increase the efficiency of a converter as a function of variations in its load. [0008] According to a first aspect of the invention, a device for controlling the power supply of a plurality of light sources is proposed. Subsets of light sources are configured to selectively perform different light functions of a motor vehicle. The control device comprises a converter circuit controlled by a control unit. The control device is remarkable in that the converter circuit is a synchronous switching converter circuit comprising two transistors, in that the control unit is configured to provide a switching signal to the converter circuit, and in that the frequency of said switching signal is dependent on an average intensity of electric charging current to be provided to the light sources, an indication of which is provided by an input signal and which depends on the light functions to be performed. [0009] It is understood that the fact that the frequency is dependent on the average current intensity to be supplied means that the control device is configured to, in an initial state, receive a first indication of average non-zero load electric current intensity, and supply a first corresponding average non-zero load electric current intensity, by supplying a switching signal clocked at a first frequency; and, in a subsequent state, receive a second indication of average non-zero load electric current intensity by the input signal, which is different from the first, and supply a second corresponding average non-zero load electric current intensity, by supplying a switching signal clocked at a second non-zero frequency different from the first non-zero frequency. [0010] A switching signal is understood to mean a signal intended to switch the transistors of the converter. Preferably, the switching sig