Vehicle headlight control device, vehicle headlight assembly, and vehicle

Abstract

The application discloses a vehicle headlamp control device, a vehicle headlamp assembly and a vehicle. The vehicle headlamp control device comprises a power supply module, a comparison module and a headlamp control module. The voltage value of a power supply signal generated by the power supply module changes with the resistance value of an NTC resistor. The comparison module comprises a first input end, a second input end and a first output end. The headlamp control module comprises an analog dimming end, a digital dimming end and a second output end. In the case that the voltage of the power supply signal is greater than or equal to the voltage of a reference signal, a second control signal is associated with the power supply signal. In the case that a first control signal is output at the first output end, the digital dimming mode of the headlamp control module is enabled, and the second control signal is a signal output in the digital dimming mode. The application does not need to configure an MCU chip, and the cost can be reduced.

Description

Technical Field

[0001] This application relates to the field of vehicle headlights, and in particular to a vehicle headlight control device, a vehicle headlight assembly, and a vehicle. Background Technology

[0002] With the development of vehicle lighting, light-emitting diodes (LEDs) are now commonly used as the light source. However, LEDs are prone to performance degradation at high temperatures, such as reduced brightness and accelerated light decay, which severely impacts their lifespan and reliability. Vehicle headlights require high-brightness LEDs with high power output, necessitating negative temperature coefficient (NTC) resistors for effective temperature control. When the temperature reaches a certain level, the LED current is reduced to lower the LED temperature, thereby reducing the probability of LED damage in the vehicle headlights.

[0003] In related technologies, the temperature control scheme for vehicle headlights typically uses a microcontroller unit (MCU) to identify the resistance value of an NTC resistor to determine the headlight temperature. The MCU then controls the output current of the LED headlight control module based on the temperature reading, thereby reducing the LED temperature. The drawback of this scheme is the need for an MCU chip, which results in high costs. Utility Model Content

[0004] This application proposes a vehicle headlight control device, a vehicle headlight assembly, and a vehicle that does not require an MCU chip, thereby reducing costs.

[0005] A control device for vehicle headlights according to a first aspect embodiment of this application includes:

[0006] A power supply module is electrically connected to an NTC resistor inside the vehicle headlight, and the voltage value of the power supply signal generated by the power supply module changes with the resistance value of the NTC resistor.

[0007] The comparison module includes a first input terminal, a second input terminal, and a first output terminal. The first input terminal is electrically connected to the power supply module and is used to input the power supply signal. The second input terminal is used to input a reference signal. The first output terminal is used to output a first control signal when the voltage of the power supply signal is less than the voltage of the reference signal.

[0008] A headlight control module includes an analog dimming terminal, a digital dimming terminal, and a second output terminal. The analog dimming terminal is electrically connected to the power supply module and is used to input the power supply signal. The digital dimming terminal is electrically connected to the first output terminal. The second output terminal is electrically connected to the vehicle headlight and is used to output a second control signal, wherein:

[0009] When the voltage of the power supply signal is greater than or equal to the voltage of the reference signal, the second control signal is associated with the power supply signal;

[0010] When the first control signal is output at the first output terminal, the digital dimming mode of the headlight control module is enabled, and the second control signal is the signal output under the digital dimming mode.

[0011] According to some embodiments of this application, it also includes:

[0012] A dimming mode switching circuit, wherein the dimming mode switching circuit is electrically connected to the first output terminal and the power supply module, wherein:

[0013] When the first control signal is input to the dimming mode switching circuit, the dimming mode switching circuit pulls up the input voltage of the analog dimming terminal.

[0014] According to some embodiments of this application, the power supply module includes a power supply, which is electrically connected to the NTC resistor and the analog dimming terminal;

[0015] The dimming mode switching circuit includes:

[0016] The first switching transistor has its input terminal electrically connected to the power supply, its output terminal connected to the analog dimming terminal via a first resistor, and its control terminal electrically connected to the first output terminal. The first switching transistor is turned on when the first control signal is output from the first output terminal.

[0017] According to some embodiments of this application, the first switching transistor is a PMOS transistor, and the dimming mode switching circuit further includes:

[0018] The transistor has its first output terminal connected to the base of the transistor via a first diode, its emitter grounded, and its collector connected to the control terminal of the first switching transistor.

[0019] According to some embodiments of this application, the dimming mode switching circuit further includes:

[0020] Overvoltage protection circuit, wherein the overvoltage protection circuit is electrically connected to the first switching transistor, wherein:

[0021] If the voltage of the power supply is overvoltage, the overvoltage protection circuit will turn off the first switching transistor.

[0022] According to some embodiments of this application, the analog dimming end includes:

[0023] A first analog dimming pin is electrically connected to the power supply module and is used to input the power supply signal.

[0024] The second analog dimming pin is electrically connected to the power supply module and is used to input the power supply signal.

[0025] According to some embodiments of this application, the comparison module further includes a third input terminal, a fourth input terminal, and a third output terminal;

[0026] The third input terminal is electrically connected to the power supply module and is used to input the power supply signal; the fourth input terminal is used to input a reference signal; the third output terminal is used to output a third control signal when the voltage of the power supply signal is less than the voltage of the reference signal.

[0027] The device further includes:

[0028] A pulse width modulation (PWM) control circuit, wherein the input terminals of the PWM control circuit are electrically connected to the first output terminal and the third output terminal respectively, and the output terminal of the PWM control circuit is connected to the digital dimming terminal, wherein:

[0029] When the first control signal is output at the first output terminal and the third control signal is output at the third output terminal, the digital dimming mode of the headlight control module is enabled, and the second control signal is the signal output under the digital dimming mode.

[0030] According to some embodiments of this application, the pulse width modulation control circuit includes:

[0031] The second switching transistor has its control terminal connected to the first output terminal via a second diode, and its control terminal is connected to the third output terminal via a third diode.

[0032] The first voltage divider circuit includes a second resistor, a third resistor, and a fourth resistor. The power supply module is grounded through the second resistor and the third resistor connected in series. The common terminal of the second resistor and the third resistor is connected to the digital dimming terminal. The common terminal of the second resistor and the third resistor is connected to the input terminal of the second switching transistor through the fourth resistor. The output terminal of the second switching transistor is grounded.

[0033] According to a second aspect of this application, a vehicle headlight assembly includes a vehicle headlight and a vehicle headlight control device as described in the first aspect embodiment. An NTC resistor is provided inside the vehicle headlight, and the vehicle headlight control device is connected to the vehicle headlight and the NTC resistor.

[0034] A vehicle according to a third aspect of this application includes a vehicle headlight control device as described in a second aspect embodiment.

[0035] The vehicle headlight control device, vehicle headlight assembly, and vehicle according to the embodiments of this application have at least the following beneficial effects:

[0036] In this embodiment, the headlight control module is equipped with an analog dimming terminal and a digital dimming terminal. The analog dimming terminal is electrically connected to the power supply module and is used to input the power supply signal. When the temperature of the car headlight rises, the resistance of the NTC resistor decreases, and the input voltage of the analog dimming terminal decreases. When the voltage of the power supply signal is greater than or equal to the voltage of the reference signal, the second control signal is associated with the power supply signal. Therefore, the headlight control module reduces the current of the second control signal, thereby reducing the temperature of the car headlight by reducing the current. Furthermore, when the resistance of the NTC resistor continues to decrease until the voltage of the power supply signal is less than the voltage of the reference signal, the comparator module outputs a first control signal. At this time, the digital dimming mode of the headlight control module is enabled. The second control signal is the signal output in the digital dimming mode. At this time, the headlight control module reduces the average current through pulse width modulation dimming, further reducing the temperature of the car headlight. This application does not require the configuration of an MCU chip, which can reduce costs.

[0037] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0038] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0039] Figure 1 A schematic block diagram of the vehicle headlight control device provided in this application;

[0040] Figure 2 A circuit diagram of the vehicle headlight control device provided in this application;

[0041] Icon labels:

[0042] Power supply module 100, NTC resistor 200, comparator module 300, first input terminal 310, second input terminal 320, first output terminal 330, headlight control module 400, analog dimming terminal 410, digital dimming terminal 420, second output terminal 430. Detailed Implementation

[0043] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0044] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0045] In the description of this application, "multiple" refers to two or more. The use of "first" and "second" is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or the order in which the technical features are indicated.

[0046] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0047] To address the problems of the prior art, embodiments of this application provide an auxiliary power supply device, a charger, and a vehicle. The auxiliary power supply device provided in the embodiments of this application will be described first.

[0048] refer to Figure 1 As shown, the first aspect of this application relates to a control device for vehicle headlights, comprising:

[0049] The power supply module 100 is electrically connected to the NTC resistor 200 in the vehicle headlight, and the voltage value of the power supply signal generated by the power supply module 100 changes with the resistance value of the NTC resistor 200.

[0050] The comparison module 300 includes a first input terminal 310, a second input terminal 320, and a first output terminal 330. The first input terminal 310 is electrically connected to the power supply module 100 and is used to input a power supply signal. The second input terminal 320 is used to input a reference signal. The first output terminal 330 is used to output a first control signal when the voltage of the power supply signal is less than the voltage of the reference signal.

[0051] The headlight control module 400 includes an analog dimming terminal 410, a digital dimming terminal 420, and a second output terminal 430. The analog dimming terminal 410 is electrically connected to the power supply module 100 and is used to input a power supply signal; the digital dimming terminal 420 is electrically connected to the first output terminal 330; and the second output terminal 430 is electrically connected to the vehicle headlight and is used to output a second control signal.

[0052] When the voltage of the power supply signal is greater than or equal to the voltage of the reference signal, the second control signal is associated with the power supply signal;

[0053] When the first control signal is output at the first output terminal 330, the digital dimming mode of the headlight control module 400 is enabled, and the second control signal is the signal output in the digital dimming mode.

[0054] In this embodiment, the headlight control module 400 is provided with an analog dimming terminal 410 and a digital dimming terminal 420. The analog dimming terminal 410 is electrically connected to the power supply module 100 and is used to input the power supply signal. When the temperature of the car headlight rises, the resistance of the NTC resistor 200 decreases, and the input voltage of the analog dimming terminal 410 decreases. When the voltage of the power supply signal is greater than or equal to the voltage of the reference signal, the second control signal is associated with the power supply signal. Therefore, the headlight control module 400 reduces the current of the second control signal, thereby reducing the temperature of the car headlight. Furthermore, when the resistance of the NTC resistor 200 continues to decrease until the voltage of the power supply signal is less than the voltage of the reference signal, the comparator module 300 outputs a first control signal. At this time, the digital dimming mode of the headlight control module 400 is enabled. The second control signal is the signal output in the digital dimming mode. At this time, the headlight control module 400 reduces the average current through pulse width modulation dimming, further reducing the temperature of the car headlight. This application does not require the configuration of an MCU chip, which can reduce costs.

[0055] The aforementioned power supply module 100 refers to the relevant modules and voltage divider circuits that provide power supply voltage. It can be a separate low-voltage power supply or it can use the power supply voltage of the chip. For example, it can directly share the input voltage of the power supply terminal of the headlight control module 400 as the power supply module 100.

[0056] The aforementioned power supply module 100 is electrically connected to the NTC resistor 200 inside the vehicle headlight, and the voltage value of the power supply signal generated by the power supply module 100 changes with the resistance value of the NTC resistor 200. This means that the power supply module 100 and the NTC resistor 200 are connected in series. When the temperature of the vehicle headlight rises, the resistance value of the NTC resistor 200 decreases. Since the power supply module 100 and the NTC resistor 200 are connected in series, the change in the resistance value of the NTC resistor 200 will affect the voltage value of the power supply signal. For example, if the power supply module 100 is grounded through the NTC resistor 200, and the NTC resistor 200 is used as a pull-down resistor for a certain port, when the NTC resistance decreases, the input voltage of that port also decreases. In other words, the voltage value of the power supply signal generated by the power supply module 100 decreases as the NTC resistance decreases.

[0057] The aforementioned comparison module 300 refers to one, two, or more comparators. The first input terminal 310 of the comparison module 300 receives a power supply signal, and the second input terminal 320 receives a reference signal. Since the voltage of the power supply signal changes with the resistance value of the NTC resistor 200, while the voltage of the reference signal is a fixed voltage, the first output terminal 330 is used to output a first control signal when the voltage of the power supply signal is less than the voltage of the reference signal. This means that when the resistance value of the NTC resistor 200 drops to a preset threshold, the comparison module 300 outputs the first control signal. The first control signal can be either a high level or a low level. In this embodiment, the first control signal is a high level.

[0058] The aforementioned headlight control module 400 refers to the drive control module of the vehicle headlights, such as a drive control chip (Integrated Circuit-IC). The analog dimming of the headlight control module 400 controls the brightness of the light by adjusting the magnitude of the current. That is, the analog dimming terminal 410 is the curve setting terminal of the vehicle headlight in the analog dimming derating process. The analog dimming controls the brightness of the light by adjusting the magnitude of the current. Therefore, the headlight control module 400 adjusts the current output to the vehicle headlights proportionally according to the input voltage value of the analog dimming terminal 410.

[0059] The analog dimming terminal 410 is electrically connected to the power supply module 100 and is used to input power supply signals. The analog dimming terminal 410 can be directly connected to the power supply module 100 through the NTC resistor 200; alternatively, the analog dimming terminal 410 can be connected to the power supply module 100 through a voltage divider resistor and then grounded through the NTC resistor 200. That is, the NTC resistor 200 acts as a pull-down resistor. When the NTC resistor 200 acts as a pull-down resistor, the resistance of the NTC resistor 200 decreases when the temperature of the vehicle headlights rises. Therefore, the input voltage of the analog dimming terminal 410 also decreases due to the pull-down effect of the NTC resistor 200. Thus, the headlight control module 400 can proportionally adjust the current output to the vehicle headlights according to the input voltage value of the analog dimming terminal 410.

[0060] The aforementioned digital dimming terminal 420 refers to the dimming pin used to set the drive control module for PWM dimming or other digital dimming modes, such as a PWM dimming pin. The digital dimming terminal 420 is electrically connected to the first output terminal 330. This connection can be direct or via an intermediate circuit, such as a pulse width modulation control circuit. The headlight control module 400 determines whether the digital dimming mode is enabled based on the input voltage of the digital dimming terminal 420. When the digital dimming mode is enabled, the headlight control module 400 reduces the average output current through PWM dimming, thereby achieving the purpose of derating the vehicle's headlights.

[0061] The aforementioned second output terminal 430 is electrically connected to the vehicle headlights and is used to output a second control signal. This means that the output terminal of the headlight control module 400 is electrically connected to the vehicle headlights; that is, the vehicle headlights act as a load, and the output terminal of the headlight control module 400 is connected to the load terminal. The aforementioned second control signal refers to the voltage and current output by the headlight control module 400 to the vehicle headlights. The headlight control module 400 can control the voltage and current output to the vehicle headlights, thereby controlling the power of the vehicle headlights.

[0062] The above-mentioned situation where the voltage of the power supply signal is greater than or equal to the voltage of the reference signal, where the second control signal is associated with the power supply signal, means that when the resistance of the NTC decreases but does not exceed the preset threshold, the voltage of the power supply signal is greater than or equal to the voltage of the reference signal. At this time, the headlight control module 400 reduces the output current by simulating dimming, that is, the headlight control module 400 adjusts the current of the second control signal proportionally according to the input voltage of the simulating dimming terminal 410.

[0063] When the first control signal is output at the first output terminal 330, the digital dimming mode of the headlight control module 400 is enabled, and the second control signal is the signal output in the digital dimming mode. This means that when the resistance of the NTC continues to decrease and exceeds the preset threshold, the headlight control module 400 maintains the current output current and no longer continues to decrease. The headlight control module 400 switches from analog dimming mode to digital dimming mode, such as switching to PWM dimming to reduce the average current of the vehicle headlights and achieve a further de-rating effect.

[0064] Therefore, in the process of derating automotive headlights when they reach a set temperature, this application divides the entire derating process into a first stage and a second stage. In the first stage, derating is achieved through analog dimming, and in the second stage, it is achieved through PWM dimming. At higher brightness levels, analog dimming provides smooth and continuous brightness changes; PWM dimming, on the other hand, can precisely control brightness by adjusting the duty cycle without changing the LED current, maintaining color temperature consistency even at extremely low brightness levels. Therefore, this application combines analog and digital dimming to achieve derating control of automotive headlights, and can also improve the continuity and stability of the derating process. This application does not require an MCU chip, only a comparator module 300. The cost of a comparator is lower than that of an MCU, and it eliminates the need for MCU-related software development and testing, thus reducing costs.

[0065] It should be noted that when derating is achieved through PWM dimming in the second stage, the analog dimming terminal 410 can be disconnected by setting the switching circuit, or the input voltage of the analog dimming terminal 410 can be changed by setting the switching circuit so that it is not within the working range of analog dimming. Alternatively, the power of the headlight control module 400 can be reduced to a preset value and then the current output can be maintained, so that analog dimming no longer works.

[0066] In some implementations, it may also include:

[0067] The dimming mode switching circuit is electrically connected to the first output terminal 330 and the power supply module 100, wherein:

[0068] When the first control signal is input to the dimming mode switching circuit, the dimming mode switching circuit pulls up the input voltage of the analog dimming terminal 410.

[0069] In this embodiment, a dimming mode switching circuit electrically connected to the first output terminal 330 and the power supply module 100 is provided. When a first control signal is input to the dimming mode switching circuit, the input voltage of the analog dimming terminal 410 is pulled up by the dimming mode switching circuit. By pulling up the input voltage of the analog dimming terminal 410 when the first control signal is input, the digital dimming terminal 420 is enabled while the analog dimming mode of the headlight control module 400 is stopped. This can improve the stability during the derating process.

[0070] The aforementioned dimming mode switching circuit is electrically connected to the first output terminal 330 and the power supply module 100. The control terminal of the dimming mode switching circuit can be connected to the first output terminal 330 of the comparison module 300. The dimming mode switching circuit is connected between the power supply module 100 and the analog dimming terminal 410. When the resistance of the NTC resistor 200 drops to a preset threshold, the first output terminal 330 of the comparison module 300 outputs a first control signal, enabling the digital dimming terminal 420 of the headlight control module 400. At this time, derating output is performed through PWM dimming. If the analog dimming terminal 410 is still active at this time, it will work simultaneously with PWM dimming, further reducing the brightness of the car headlights. When the brightness requirement drops to a low level, analog dimming may cause color temperature changes, affecting the lighting effect of the vehicle headlights. Therefore, this application sets up a dimming mode switching circuit that, while the digital dimming terminal 420 is enabled, pulls up the input voltage of the analog dimming terminal 410, so that the input voltage of the analog dimming terminal 410 is outside the analog dimming range, meaning that the analog dimming terminal 410 does not function. This achieves seamless and smooth switching between analog and digital dimming.

[0071] In some embodiments, the power supply module 100 includes a power supply that is electrically connected to the NTC resistor 200 and the analog dimming terminal 410.

[0072] The dimming mode switching circuit may include:

[0073] The first switching transistor has its input terminal electrically connected to the power supply, its output terminal connected to the analog dimming terminal 410 via a first resistor, and its control terminal electrically connected to the first output terminal 330. The first switching transistor is turned on when the first output terminal 330 outputs a first control signal.

[0074] In this embodiment, a first switching transistor and a first resistor are provided between the power supply and the analog dimming terminal 410. When the first output terminal 330 outputs a first control signal, the first switching transistor is turned on, which can pull up the input voltage of the analog dimming terminal 410, so that the input voltage of the analog dimming terminal 410 is outside the analog dimming range. This enables seamless and smooth switching between analog dimming and digital dimming at a low cost.

[0075] Specifically, the first switching transistor can be a MOSFET, a transistor, or any other switching device. For example, an NMOS transistor can be used, with its gate connected to the first output terminal 330. When the first output terminal 330 outputs a high level, the NMOS transistor turns on, pulling up the input voltage of the analog dimming terminal 410 through the first resistor. Of course, a PMOS transistor or other switching devices can also be used.

[0076] In some implementations, the first switching transistor is a PMOS transistor, and the dimming mode switching circuit may further include:

[0077] The transistor has its first output terminal 330 connected to the base of the transistor via a first diode, its emitter grounded, and its collector connected to the control terminal of the first switching transistor.

[0078] In this embodiment, the first switching transistor is set as a PMOS transistor, and a bipolar transistor is placed between the first output terminal 330 and the gate of the PMOS transistor. When the first output terminal 330 outputs a high level, the bipolar transistor is turned on, the gate of the PMOS transistor is grounded, the PMOS transistor is turned on, and the input voltage of the analog dimming terminal 410 is pulled up, causing the headlight control module 400 to enter digital dimming mode and exit analog dimming mode. This achieves seamless and smooth switching between analog dimming and digital dimming at a low cost.

[0079] In some implementations, the dimming mode switching circuit further includes:

[0080] Overvoltage protection circuit, which is electrically connected to the first switching transistor, wherein:

[0081] When the power supply voltage is overvoltage, the overvoltage protection circuit turns off the first switching transistor.

[0082] In this embodiment, an overvoltage protection circuit is incorporated to ensure that the first switching transistor is turned off when the power supply voltage is excessive. This prevents the first switching transistor from burning out when the power supply voltage is too high, thus improving the reliability of the circuit.

[0083] Specifically, taking a PMOS transistor as an example, the drain of the PMOS transistor is connected to the power supply. A Zener diode and a resistor are connected in parallel between the drain and the gate of the PMOS transistor. The cathode of the Zener diode is connected to the drain of the PMOS transistor, and the anode of the Zener diode is connected to the gate of the PMOS transistor. When the voltage of the power supply is within the normal range, the Zener diode plays a role in voltage regulation. When the voltage of the power supply is greater than the reverse breakdown voltage of the Zener diode, the Zener diode breaks down in reverse, which causes the gate voltage of the PMOS transistor to rise, and thus causes the PMOS transistor to be turned off.

[0084] In some implementations, the analog dimming terminal 410 may include:

[0085] The first analog dimming pin is electrically connected to the power supply module 100 and is used to input a power supply signal.

[0086] The second analog dimming pin is electrically connected to the power supply module 100 and is used to input power supply signals.

[0087] In this embodiment, the headlight control module 400 performs analog dimming simultaneously through two analog dimming pins, which can improve the derating speed of analog dimming.

[0088] For example, the driver control IC has a first analog dimming pin ICTRL and a second analog dimming pin ADJR. Both ICTRL and ADJR are connected to the power supply via voltage divider resistors, and both are grounded via an NTC resistor 200. Therefore, when the resistance of the NTC resistor 200 decreases, the input voltages of both ICTRL and ADJR change accordingly. The driver control IC performs analog dimming based on the input voltages of ICTRL and ADJR. Testing has shown that using two analog dimming pins simultaneously improves the derating speed of analog dimming compared to a circuit using only one analog dimming pin.

[0089] In some implementations, the comparison module 300 further includes a third input terminal, a fourth input terminal, and a third output terminal;

[0090] The third input terminal is electrically connected to the power supply module 100 and is used to input a power supply signal; the fourth input terminal is used to input a reference signal; the third output terminal is used to output a third control signal when the voltage of the power supply signal is less than the voltage of the reference signal.

[0091] The device may also include:

[0092] A pulse width modulation (PWM) control circuit is included. The input terminals of the PWM control circuit are electrically connected to the first output terminal 330 and the third output terminal, respectively. The output terminal of the PWM control circuit is connected to the digital dimming terminal 420.

[0093] When the first control signal is output at the first output terminal 330 and the third control signal is output at the third output terminal, the digital dimming mode of the headlight control module 400 is enabled, and the second control signal is the signal output in the digital dimming mode.

[0094] In this embodiment, a second comparator is formed by the third input terminal, the fourth input terminal, and the third output terminal. The PWM dimming of the two PWM control loops is realized by the two comparators and the pulse width modulation control circuit, which can ensure the stability of the droop curve of the vehicle headlight PWM dimming mode.

[0095] The aforementioned comparison module 300 also includes a third input terminal, a fourth input terminal, and a third output terminal. This means the comparison module 300 includes two comparators: the first comparator includes a first input terminal 310, a second input terminal 320, and a first output terminal 330; the second comparator includes a third input terminal, a fourth input terminal, and a third output terminal. The input terminals of both the first and second comparators receive a reference voltage and a power supply signal, respectively, to monitor the resistance value of the NTC resistor 200. When the resistance value of the NTC resistor 200 drops to a threshold value, the voltage of the power supply signal is less than the voltage of the reference signal. Both the first and second comparators then output a high level; that is, the first output terminal 330 outputs a first control signal, and the third output terminal outputs a third control signal.

[0096] When the pulse width modulation (PWM) control circuit receives a high-level signal at its input, the digital dimming terminal 420 is enabled, and the headlight control module 400 enters PWM dimming mode. It should be noted that test data revealed that the NTC derating curve of a single-channel PWM dimming system does not overlap with that of the MCU solution in related technologies, exhibiting a partial collapse. The overlap of the derating curves using two-channel PWM dimming is consistent with the MCU solution. Therefore, PWM dimming with two PWM control loops can ensure the stability of the derating curve in the vehicle's headlight PWM dimming mode.

[0097] In some implementations, the pulse width modulation control circuit may include:

[0098] The control terminal of the second switching transistor is connected to the first output terminal 330 through the second diode, and the control terminal of the second switching transistor is connected to the third output terminal through the third diode.

[0099] The first voltage divider circuit includes a second resistor, a third resistor, and a fourth resistor. The power supply module 100 is grounded through the second and third resistors connected in series. The common terminal of the second and third resistors is connected to the digital dimming terminal 420. The common terminal of the second and third resistors is connected to the input terminal of the second switching transistor through the fourth resistor. The output terminal of the second switching transistor is grounded.

[0100] In this embodiment, a pulse width modulation (PWM) control circuit is constructed using a second switching transistor and a first voltage divider circuit. When the comparator module 300 outputs a high level, the second switching transistor is turned on. The first voltage divider circuit, composed of a second resistor, a third resistor, and a fourth resistor, pulls down the input voltage of the digital dimming terminal 420 to a preset range, thereby enabling the digital dimming terminal 420. The PWM dimming mode can be turned on and off based on the output level of the comparator module 300, further improving the overall circuit reliability.

[0101] In this embodiment, the second switching transistor can be a MOSFET, a transistor, or any other switching device. For example, an NMOS transistor can be used. The gate of the NMOS transistor is connected to the first output terminal 330 and the third output terminal through a diode. When the first output terminal 330 and the third output terminal output a high level, the NMOS transistor is turned on, and the voltage of the power supply is pulled down by the second and third resistors. When the NMOS transistor is turned on, the third and fourth resistors are connected in parallel. The parallel resistance decreases, and the voltage input to the digital dimming terminal 420 drops to the operating range, enabling the digital dimming terminal 420. Of course, a PMOS transistor or other switching devices can also be used. It should be understood that when using a PMOS transistor or a transistor or other switching transistor, the corresponding circuit needs to be adjusted accordingly.

[0102] The following describes a specific circuit example of this application, for reference... Figure 2 As shown, the circuit structure of a vehicle headlight control device is as follows:

[0103] The power supply module includes a power supply VDD LB as the power source and voltage divider resistors such as resistors R3 and R4. The power supply VDD LB is the 6.6V operating voltage of the drive control IC.

[0104] The comparator module includes a comparator UIB, which contains two comparators. The first input corresponds to pin -INB, the second input corresponds to pin +INB, and the first output corresponds to pin OUTB. Similarly, the third, fourth, and third inputs correspond to pins -INA, +INA, and OUTA, respectively.

[0105] The headlight control module includes a drive control IC. The analog dimming pins of the drive control IC include a first analog dimming pin (ICTRL) and a second analog dimming pin (ADJR). The digital dimming pin is PWMDC. The second output pins are ISP and ISN. The ISP and ISN pins of the drive control IC are connected to the output load terminal via resistors R32, R34, R33, and R35. The output load terminal has capacitors C11, C12, C13, and C14 connected in parallel, along with a filter and energy storage inductor. Capacitors C11, C12, C13, and C14 are filter and energy storage capacitors. The vehicle headlights include three loads: LED1, LED2, and LED3, all connected to the output load terminal. It should be understood that the number of loads for the vehicle headlights is not limited to three LEDs; the number of LEDs can be increased or decreased according to actual needs.

[0106] The dimming mode switching circuit includes MOSFET Q1, transistor T1, diode D1, resistor R10, resistor R11, resistor R2, etc.

[0107] The pulse width modulation control circuit includes MOSFET Q2, resistors R12, R13, R16, R17, and R18.

[0108] Specifically, the power supply VDD LB is connected to the first analog dimming pin ICTRL via resistors R4 and R6 connected in series. Resistor R4 is the first resistor. The first analog dimming pin ICTRL is grounded via resistors R6, R9, and NTC resistor R20 connected in series. The power supply VDD LB is connected to the second analog dimming pin ADJR via resistor R3. The second analog dimming pin ADJR is grounded via resistors R3, R4, R9, and NTC resistor R20 connected in series. The power supply VDD LB is connected to the drain of MOSFET Q1, and the source of MOSFET Q1 is connected to one end of resistor R5. MOSFET Q1 is a PMOS transistor. The output pin OUTB of comparator UIB is connected to the base of transistor T1 via a series connection of diode D1, resistor R10, and resistor R11. Diode D1 is the first diode. The emitter of transistor T1 is grounded. The collector of transistor T1 is connected to the gate of MOSFET Q1 via resistor R2. A parallel connection of Zener diode Z1 and resistor R1 is used between the drain and gate of MOSFET Q1 as an overvoltage protection circuit. When the voltage of the power supply VDD LB exceeds the reverse breakdown voltage of Zener diode Z1, Zener diode Z1 breaks down in reverse, causing the gate voltage of MOSFET Q1 to rise. MOSFET Q1 then turns off, thus achieving overvoltage protection.

[0109] The specific working process of analog dimming is as follows: The operating voltage VDD LB of the driver control IC is divided by resistors R4, R9, and NTC resistor R20, and then enters the first analog dimming pin ICTRL of the IC through resistor R6. When the temperature of the vehicle headlights rises, the temperature of the NTC resistor R20, which acts as a pull-down resistor, also rises and its resistance decreases. Therefore, the dimming voltage entering the first analog dimming pin ICTRL also decreases. The driver control IC will then reduce the output current according to the input voltage of the first analog dimming pin ICTRL, thereby achieving LED derating. The working principle of the first analog dimming pin ADJR is the same as that of the first analog dimming pin ICTRL, and will not be described in detail here.

[0110] In this circuit, the power supply VDD LB is connected to the +INA pin of the comparator UIB as the input of the reference signal through a voltage divider circuit consisting of resistors R27, R28, and R26. Similarly, the power supply VDD LB is connected to the +INB pin of the comparator UIB as the input of the reference signal through a voltage divider circuit consisting of resistors R31, R30, and R29.

[0111] The comparator UIB's pin -INA is connected to the NTC resistor R20 through resistor R24, and the comparator UIB's pin -INB is connected to the NTC resistor R20 through resistor R25. Therefore, the comparator UIB can detect the change in the resistance value of the NTC resistor through pins -INA and -INB by the input voltage. The output pin OUTA of comparator UIB is connected to the gate of MOSFET Q2 via a series connection of resistor R21, diode D3, resistor R12, and resistor R13. Similarly, the output pin OUTB of comparator UIB is connected to the gate of MOSFET Q2 via a series connection of resistor R22, diode D2, resistor R12, and resistor R13, forming two PWM control loops. The second diode is D2, and the third diode is D3. The source of MOSFET Q2 is grounded, and the drain of MOSFET Q2 is connected to the PWMDC pin of the driver control IC via resistor R16. The power supply VDD LB is grounded via a series connection of resistors R17 and R18. The common terminal of resistors R17 and R18 is connected to the PWMDC pin. The second resistor is R17, the third resistor is R18, and the fourth resistor is R16. Additionally, a Zener diode Z2 is placed between the gate and drain of MOSFET Q2 to protect the gate from high voltage damage and to clamp the voltage, providing a stable input voltage to the gate of MOSFET Q2.

[0112] The specific process of switching from analog dimming to digital dimming is as follows:

[0113] When analog dimming is activated, the output current of the drive control IC decreases as the resistance of the NTC resistor R20 decreases. When it drops to a preset value, such as 0.6Ω, the input voltage of +IN A is greater than that of -IN A, and the output OUT A of the comparator UIB is high. The high level output of OUT A passes through resistor R21, pull-down resistor R19, and filter capacitor C6, then through diode D3 for unidirectional conduction, and then through resistors R12, R13, R14, and R15 for voltage division to reach the gate of MOSFET Q2, controlling the conduction and cutoff of MOSFET Q2. VDD LB is pulled down by resistors R17 and R18. When MOSFET Q2 is turned on, resistors R16 and R18 are connected in parallel. As the parallel resistance decreases, the voltage input to the PWMDC pin of the drive control IC decreases. In this embodiment, applying a voltage of 0-3V to the PWMDC pin of the drive control IC can set the internal PWM of the chip, and then adjusting the average current of the output through the PWM to achieve derating.

[0114] Simultaneously, when the OUT B output of comparator UIB is high, transistor T1 is turned on, the gate of MOSFET Q1 is pulled down to the bottom, and MOSFET Q1 is turned on. This pulls up the input voltage of the first analog dimming pin ICTRL and the second analog dimming pin ADJR to a level exceeding the allowable analog dimming range, causing the driver control IC to exit analog dimming mode. It should be understood that during the analog dimming phase, the OUT B output of comparator UIB is low, transistor T1 is turned off, and MOSFET Q1 is also turned off. Therefore, the input voltage of the first analog dimming pin ICTRL and the second analog dimming pin ADJR will not be pulled up, and analog dimming can proceed normally.

[0115] It should be understood that when the resistance of NTC resistor R20 does not drop to a preset value, for example, higher than 0.6Ω, OUT A outputs a low level, and comparators UIB's OUT A and OUT B output low levels, MOSFET Q2 is turned off. At this time, resistor R16 is disconnected, and the voltage input to the PWMDC pin of the chip control IC increases. In this embodiment, when a voltage of 3-5V is applied to the PWMDC pin, the internal PWM of the drive control IC is disabled. That is, when the inputs of UIB pins 3-IN A and -IN B are greater than those of pins +IN A and +IN B, MOSFET Q2 is turned off, and the internal PWM of the drive control IC is disabled.

[0116] When the temperature rises, the resistance of NTC resistor R20 decreases. Through resistors R24 and R25, the voltage at the UIB pins -INA and -INB decreases, so OUT A and OUT B output a high level. MOSFET Q2 turns on. At this time, the chip IC can perform internal PWM dimming, thereby adjusting the output and further achieving the derating effect.

[0117] It should be noted that the allowable dimming voltage range of the first analog dimming pin ICTRL and the second analog dimming pin ADJR of the driver control IC, as well as the enable voltage range of the pin PWMDC and the preset duty cycle of PWM dimming, are all implemented through the underlying software preset of the driver control IC. This application does not involve any software-level improvements.

[0118] The second aspect of this application discloses a vehicle headlight assembly, including a vehicle headlight and a vehicle headlight control device as described above. An NTC resistor is provided inside the vehicle headlight, and the vehicle headlight control device is connected to the vehicle headlight and the NTC resistor.

[0119] As can be seen, in the vehicle headlight assembly of the second aspect embodiment of this application, the present application replaces the MCU with a comparator, eliminating the need for an MCU chip, thereby reducing costs, and enabling switching between analog dimming and digital dimming, ensuring the stability and reliability of vehicle headlight derating.

[0120] The third aspect of this application also relates to a vehicle including the vehicle headlight control device described in the first aspect embodiment.

[0121] In this embodiment, the vehicle can be any new energy vehicle equipped with a charger, such as a hybrid vehicle or a pure electric vehicle. Specifically, the vehicle can be a private car, such as a sedan, SUV, MPV, or pickup truck. The vehicle can also be a commercial vehicle, such as a van, bus, small truck, or large trailer.

[0122] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A vehicle headlight control device, characterized in that, include: A power supply module (100) is electrically connected to an NTC resistor (200) in the vehicle headlight, and the voltage value of the power supply signal generated by the power supply module (100) changes with the resistance value of the NTC resistor (200). A comparison module (300) includes a first input terminal (310), a second input terminal (320), and a first output terminal (330). The first input terminal (310) is electrically connected to the power supply module (100) and is used to input the power supply signal. The second input terminal (320) is used to input a reference signal; the first output terminal (330) is used to output a first control signal when the voltage of the power supply signal is less than the voltage of the reference signal. A headlight control module (400) includes an analog dimming terminal (410), a digital dimming terminal (420), and a second output terminal (430). The analog dimming terminal (410) is electrically connected to the power supply module (100) and is used to input the power supply signal. The digital dimming terminal (420) is electrically connected to the first output terminal (330). The second output terminal (430) is electrically connected to the vehicle headlight and is used to output a second control signal, wherein: When the voltage of the power supply signal is greater than or equal to the voltage of the reference signal, the second control signal is associated with the power supply signal; When the first control signal is output at the first output terminal (330), the digital dimming mode of the headlight control module (400) is enabled, and the second control signal is the signal output under the digital dimming mode.

2. The vehicle headlight control device according to claim 1, characterized in that, Also includes: A dimming mode switching circuit is electrically connected to the first output terminal (330) and the power supply module (100), wherein: When the first control signal is input to the dimming mode switching circuit, the dimming mode switching circuit pulls up the input voltage of the analog dimming terminal (410).

3. The vehicle headlamp control device according to claim 2, characterized by The power supply module (100) includes a power supply, which is electrically connected to the NTC resistor (200) and the analog dimming terminal (410); The dimming mode switching circuit includes: The first switching transistor has its input terminal electrically connected to the power supply, its output terminal connected to the analog dimming terminal (410) via a first resistor, and its control terminal electrically connected to the first output terminal (330). The first switching transistor is turned on when the first control signal is output from the first output terminal (330).

4. The vehicle headlamp control device according to claim 3, characterized by The first switching transistor is a PMOS transistor, and the dimming mode switching circuit further includes: The transistor has its first output terminal (330) connected to the base of the transistor via a first diode, its emitter grounded, and its collector connected to the control terminal of the first switching transistor.

5. The vehicle headlight control device according to claim 3, characterized in that, The dimming mode switching circuit also includes: Overvoltage protection circuit, wherein the overvoltage protection circuit is electrically connected to the first switching transistor, wherein: If the voltage of the power supply is overvoltage, the overvoltage protection circuit will turn off the first switching transistor.

6. The vehicle headlight control device according to claim 1, characterized in that, The analog dimming terminal (410) includes: The first analog dimming pin is electrically connected to the power supply module (100) and is used to input the power supply signal; The second analog dimming pin is electrically connected to the power supply module (100) and is used to input the power supply signal.

7. The vehicle headlight control device according to claim 1, characterized in that, The comparison module (300) also includes a third input terminal, a fourth input terminal, and a third output terminal; The third input terminal is electrically connected to the power supply module (100) and is used to input the power supply signal; The fourth input terminal is used to input a reference signal; The third output terminal is used to output a third control signal when the voltage of the power supply signal is less than the voltage of the reference signal; The device further includes: A pulse width modulation (PWM) control circuit, wherein the input terminals of the PWM control circuit are electrically connected to the first output terminal (330) and the third output terminal respectively, and the output terminal of the PWM control circuit is connected to the digital dimming terminal (420), wherein: When the first control signal is output at the first output terminal (330) and the third control signal is output at the third output terminal, the digital dimming mode of the headlight control module (400) is enabled, and the second control signal is the signal output under the digital dimming mode.

8. The vehicle headlight control device according to claim 7, characterized in that, The pulse width modulation control circuit includes: The second switch is connected to the first output terminal (330) via a second diode, and the control terminal of the second switch is connected to the third output terminal via a third diode. The first voltage divider circuit includes a second resistor, a third resistor, and a fourth resistor. The power supply module (100) is grounded through the second resistor and the third resistor connected in series. The common terminal of the second resistor and the third resistor is connected to the digital dimming terminal (420). The common terminal of the second resistor and the third resistor is connected to the input terminal of the second switching transistor through the fourth resistor. The output terminal of the second switching transistor is grounded.

9. A vehicle headlight assembly, characterized in that, The device includes a vehicle headlight and a vehicle headlight control device as described in any one of claims 1 to 8, wherein an NTC resistor (200) is provided inside the vehicle headlight, and the vehicle headlight control device is connected to the vehicle headlight and the NTC resistor (200).

10. A vehicle, characterized in that, Includes the vehicle headlight control device as described in any one of claims 1 to 8.

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