Vehicle lighting fixture

Abstract

Each output terminal OUTi of a dimming IC 310 is connected to a second end of a corresponding light-emitting element 402_i. A microcontroller 302 controls the dimming IC 310 on the basis of an instruction from a vehicle-side ECU 110, and asserts an error signal ERR upon detection of abnormality. A first auxiliary drive circuit 320 is connected to a second end of a marker lamp element 402_1 that functions as a first marker lamp among a plurality of light-emitting elements 402_1 to 402_N. The first auxiliary drive circuit 320 is enabled when the error signal ERR is asserted, and supplies a drive current Iaux1 to the marker lamp element 402_1 upon receiving an input of a first power supply voltage Vstop for instructing lighting of the first marker lamp.

Description

Vehicle lamp

[0001] The present disclosure relates to a vehicle lamp.

[0002] Automobiles are equipped with various types of lamps such as headlamps, small lamps (side marker lamps), turn lamps (turn signals, direction indicators), hazard lamps (emergency lamps), tail lamps, stop lamps (brake lamps), fog lamps, etc.

[0003] In recent years, as part of vehicle design, in addition to these lamps, some vehicles are also equipped with a lamp for animation effect (referred to as animation lamp in the present specification).

[0004] An animation lamp is composed of a combination of a plurality of light-emitting elements and a dimming circuit (lighting circuit). The dimming circuit individually controls the brightness, on and off states of the plurality of light-emitting elements based on a sequence corresponding to the animation.

[0005] Japanese Patent Application Laid-Open No. 2024-38811

[0006] The dimming circuit of an animation lamp has multi-channel outputs. The inventor of the present invention studied a system that uses one or more of the plurality of channels to drive an existing lamp, and came to recognize the following problem. Here, it is assumed that the existing lamp is a tail lamp.

[0007] In such a system, when a failure occurs in the dimming circuit, or when an abnormality occurs in communication with the vehicle-side ECU, the tail lamp becomes uncontrollable.

[0008] It should be noted that this problem can occur not only in animation lamps, but also in systems that drive a plurality of light-emitting elements by a single dimming circuit.

[0009] The present disclosure is made in such a context, and one exemplary objective of an embodiment thereof is to provide a vehicle lamp capable of controlling an existing lamp when an abnormality occurs.

[0010] A vehicle lighting device in one aspect of the present disclosure includes: a plurality of light-emitting elements whose first ends are connected in common; a dimming circuit having a plurality of output terminals, each output terminal being connected to the second end of the corresponding light-emitting element and capable of individually controlling the current flowing through the plurality of light-emitting elements; a microcontroller that communicates with a vehicle-side control device, controls the dimming circuit based on instructions from the vehicle-side control device, and asserts an error signal when it detects an abnormality; and a first auxiliary drive circuit connected to the second end of the marker light element, when a portion of the plurality of light-emitting elements that functions as a first marker light is referred to as a marker light element. The first auxiliary drive circuit is switchable between an enabled state and a disabled state, and is enabled when an error signal is asserted, and is configured to supply a drive current to the marker light element when a first power supply voltage that instructs the lighting of the first marker light is input while enabled.

[0011] Furthermore, any combination of the above components, or any substitution of the components or expressions of this disclosure between methods, apparatus, systems, etc., are also valid forms of this disclosure.

[0012] According to one aspect of this disclosure, the functionality of the existing lamp can be maintained even in the event of an abnormality.

[0013] This is a block diagram showing the configuration of a lighting system according to an embodiment. This is a circuit diagram showing an example of the configuration of the first auxiliary drive circuit. This is a diagram showing an example of a lighting system. This is a circuit diagram of a lighting system according to modified example 1. This is a circuit diagram showing an example of the configuration of the first auxiliary drive circuit and the second auxiliary drive circuit. This is a circuit diagram of a lighting system according to modified example 2.

[0014] (Outline of Embodiments) An outline of some exemplary embodiments of this disclosure is provided below. This outline is intended to provide a basic understanding of the embodiments and to serve as a prelude to the detailed descriptions that follow later. It simplifies some concepts of one or more embodiments and does not limit the scope of the disclosure. Furthermore, this outline is not a comprehensive overview of all possible embodiments and does not limit the essential components of the embodiments. For convenience, “one embodiment” may be used to refer to one embodiment (example or variation) or more embodiments (example or variation) disclosed herein.

[0015] A vehicle lighting device according to one embodiment includes: a plurality of light-emitting elements whose first ends are connected in common; a dimming circuit having a plurality of output terminals, each output terminal being connected to the second end of the corresponding light-emitting element and capable of individually controlling the current flowing through the plurality of light-emitting elements; a microcontroller that communicates with a vehicle-side control device, controls the dimming circuit based on instructions from the vehicle-side control device, and asserts an error signal when an abnormality is detected; and a first auxiliary drive circuit connected to the second end of the marker light element, when a portion of the plurality of light-emitting elements that functions as a first marker light is referred to as a marker light element. The first auxiliary drive circuit is switchable between an enabled state and a disabled state, and is enabled when an error signal is asserted. In the enabled state, when a first power supply voltage that instructs the lighting of the first marker light is input, it is configured to supply a drive current to the marker light element.

[0016] In this embodiment, when the system is functioning normally, the error signal is negated, the first auxiliary drive circuit is disabled, and the marker light element is controlled by the dimming circuit. When an abnormality occurs, the error signal is asserted, and the first auxiliary drive circuit is enabled. When the first power supply voltage that instructs the marker light element to turn on is supplied, the first auxiliary drive circuit can maintain the function of the marker light by supplying a drive current to the marker light element.

[0017] In one embodiment, the indicator light element may also function as a second indicator light and may further include a second auxiliary drive circuit connected to the second end of the indicator light element. The second auxiliary drive circuit may be switchable between an enabled state and a disabled state, becoming enabled when an error signal is asserted, and in the enabled state, when a second power supply voltage instructing the lighting of the second indicator light is input, it may be configured to supply a drive current to the indicator light element. This allows the indicator light element to have two functions.

[0018] In one embodiment, the second auxiliary drive circuit may be disabled when the first power supply voltage is input, regardless of the error signal. This allows the instruction to light the first indicator light to be prioritized when the first and second power supply voltages are supplied simultaneously, and the indicator light element to emit light at a brightness corresponding to the first indicator light.

[0019] In one embodiment, the first indicator light may be a stop lamp and the second indicator light may be a tail lamp.

[0020] In one embodiment, the first auxiliary drive circuit may include a first P-type transistor and a drive resistor connected in series between a first power supply terminal to which a first power supply voltage is input and an indicator light element, and a second transistor connected between the control electrode of the first transistor and ground, which switches on and off in response to an error signal.

[0021] In one embodiment, among the multiple light-emitting elements, those other than the indicator light elements may be used for animation effects.

[0022] (Embodiments) Preferred embodiments will be described below with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing will be denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate. Furthermore, the embodiments are illustrative and not limiting to the disclosure, and not all features or combinations thereof described in the embodiments are necessarily essential to the disclosure.

[0023] In this specification, "a state in which member A is connected to member B" includes not only cases in which member A and member B are directly connected physically, but also cases in which member A and member B are indirectly connected via other members that do not substantially affect their electrical connection state or impair the functions or effects produced by their connection.

[0024] Similarly, "the state in which member C is provided between member A and member B" includes not only cases where member A and member C, or member B and member C, are directly connected, but also cases where they are indirectly connected via other members that do not substantially affect their electrical connection state or impair the function or effect produced by their combination.

[0025] Figure 1 is a block diagram showing the configuration of a lighting system 100 according to an embodiment. The lighting system 100 includes a vehicle-side ECU (Electronic Control Unit) 110 and a vehicle lighting device 200. The vehicle lighting device 200 has the function of an indicator light as well as an animation lighting device. Examples of indicator lights include small lamps, turn signals, hazard lights, taillights, stop lamps, fog lamps, etc. In this embodiment, the vehicle lighting device 200 is a rear lamp installed on the rear side of the vehicle, and the indicator light is a stop lamp.

[0026] The vehicle-side ECU 110 transmits a control signal CTRL to the vehicle lighting fixture 200. The control signal CTRL includes (i) an instruction to illuminate the animation of the vehicle lighting fixture 200 and a specification of the type of animation, and (ii) an instruction to illuminate the stop lamp, which is an indicator light. The vehicle-side ECU 110 and the vehicle lighting fixture 200 are connected via a vehicle bus, such as a CAN (Controller Area Network) or a LIN (Local Interconnect Network), and the control signal CTRL is transmitted to the vehicle lighting fixture 200 via the vehicle bus.

[0027] The vehicle lighting fixture 200 comprises a drive module 300 and a light-emitting element module 400. The light-emitting element module 400 comprises a plurality of N (where N is an integer) light-emitting elements 402_1 to 402_N. The light-emitting elements 402_1 to 402_N are, for example, LEDs (light-emitting diodes), but may also be organic EL (electroluminescence) elements or semiconductor lasers (LD: laser diodes).

[0028] The first ends (cathodes) of multiple light-emitting elements 402_1 to 402_N are connected to each other in common. One of the multiple light-emitting elements 402_1 to 402_N (402_1) functions as a signal light (stop lamp). The light-emitting element 402_1 that functions as a signal light is called a signal light element. In this embodiment, the signal light element 402_1 is a stop lamp and is a red LED.

[0029] The remaining 402_2 to 402_N of the multiple light-emitting elements 402_1 to 402_N are elements for animation, and are also referred to as animation elements. The light-emitting elements 402_2 to 402_N for animation are, for example, white LEDs. The indicator light element 402_1 may also be used for animation.

[0030] The drive module 300 includes a microcontroller 302, a power supply circuit 304, a dimming IC (Integrated Circuit) 310, and a first auxiliary drive circuit 320. The microcontroller 302, also called the lighting ECU, receives a control signal CTRL from the vehicle-side ECU 110. The microcontroller 302 includes a CPU and memory and executes programs.

[0031] The power supply circuit 304 is a DC / DC converter that steps down the battery voltage Vbat to generate the power supply voltage Vdd, which is then supplied to the power supply pin VDD of the dimming IC 310.

[0032] The dimming IC 310 is an ASIC (Application Specific Integrated Circuit) that drives multiple light-emitting elements 402_1 to 402_N of the light-emitting element module 400. The dimming IC 310 has multiple output pins OUT1 to OUTN. Each output pin OUTi (i=1 to N) is connected to the second end (anode) of the corresponding light-emitting element 402_i. The dimming IC 310 individually controls the drive currents Idrv1 to IdrvN flowing through the multiple light-emitting elements 402_1 to 402_N.

[0033] The dimming IC 310 comprises a plurality of constant current drivers 312_1 to 312_N and control logic 314. The drive current Idrvi generated by the constant current driver 312_i can be controlled by analog dimming, PWM (pulse width modulation) dimming, or a combination thereof.

[0034] The control logic 314 individually controls the on / off state and current amount of multiple constant current drivers 312_1 to 312_N in response to control by the microcontroller 302.

[0035] The microcontroller 302 communicates with the vehicle-side ECU 110 and receives the control signal CTRL from the vehicle-side ECU 110. Based on the control signal CTRL, the microcontroller 302 controls the dimming IC 310.

[0036] The microcontroller 302 has data describing the waveforms of the drive currents Idrv1 to IdrvN for each type of animation. When the control signal CTRL includes an animation lighting instruction and a specification of the animation type, the microcontroller 302 causes the dimming IC 310 to generate drive currents Idrv1 to IdrvN having waveforms corresponding to the specified animation. The control signal CTRL may also include data describing the waveforms of the drive currents Idrv1 to IdrvN.

[0037] When the control signal CTRL includes an instruction to turn on the stop lamp, the microcontroller 302 controls the dimming IC 310 so that the constant current driver 312_1 generates a predetermined drive current Idrv1.

[0038] The microcontroller 302 has an anomaly detection function and asserts an error signal ERR when it detects an anomaly. The anomaly may include a communication failure with the vehicle-side ECU 110, an anomaly in the microcontroller 302 itself, an anomaly in the dimming IC 310, or an anomaly in the power supply circuit 304.

[0039] The first auxiliary drive circuit 320 is connected to the second terminal (anode) of the indicator light element 402_1. The first auxiliary drive circuit 320 can be switched between an enabled state and a disabled state, and becomes enabled when the error signal ERR is asserted. On the other hand, the dimming IC 310 becomes disabled when the error signal ERR is asserted.

[0040] In addition to the stop lamp illumination instruction included in the control signal CTRL, the drive module 300 is also supplied with the power supply voltage Vstop as a stop lamp illumination instruction. The power supply voltage Vstop takes two voltage levels: 12V (on) and 0V (off).

[0041] When the first auxiliary drive circuit 320 is enabled, if a power supply voltage Vstop that instructs the stop lamp (marker light) to light up is input, it supplies a drive current Iaux1 to the marker light element 402_1.

[0042] Figure 2 is a circuit diagram showing an example configuration of the first auxiliary drive circuit 320. The first auxiliary drive circuit 320 includes a P-type first transistor M1, a second transistor M2, and resistors R1, R2, and R3.

[0043] The first transistor M1 and the drive resistor R1 are connected in series between the first power supply terminal STOP, to which the first power supply voltage Vstop is input, and the indicator light element 402_1. The first transistor M1 may be a P-channel MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or a PNP-type bipolar transistor.

[0044] The resistor R2 is connected between the gate (or base), which is the control electrode of the first transistor M1, and the first power supply terminal STOP. The second transistor M2 is connected between the gate, which is the control electrode of the first transistor M1, and ground, and is switched on and off in response to the error signal ERR. In this example, the second transistor M2 is an NPN-type bipolar transistor. The second transistor M2 is turned on when the error signal ERR is asserted, and turned off when the error signal ERR is negated. A resistor R3 is inserted between the collector of the second transistor M2 and the gate of the first transistor M1.

[0045] In this example, for the error signal ERR, assertion is assigned to low level and negation is assigned to high level. The error signal ERR inverted by the inverter 322 is input to the base of the second transistor M2.

[0046] When the error signal ERR is asserted (low level), the base voltage of the second transistor M2 exceeds the threshold voltage, and the second transistor M2 is turned on. Thereby, the gate of the first transistor M1 is connected to ground via the resistor R3.

[0047] When the 12V power supply voltage Vstop is supplied, a voltage of Vstop×R2 / (R2+R3) is generated between the gate and source of the first transistor M1, and the first transistor M1 is turned on. At this time, a drive current Iaux1 that is inversely proportional to the resistance value of the drive resistor R1 flows through the first transistor M1. Iaux1=(Vstop−Vds−Vf) / R1 Vds is the drain-source voltage of the first transistor M1, and Vf is the forward voltage of the marker lamp element 402_1.

[0048] The configuration of the first auxiliary drive circuit 320 is not limited to that shown in FIG. 2. For example, the first auxiliary drive circuit 320 may be configured by a constant current source.

[0049] The above is the configuration of the lamp system 100. Next, the operation thereof will be described.

[0050] - When the normal drive module 300 is operating normally and communication with the vehicle-side ECU 110 is also normal, the error signal ERR is negated and the first auxiliary drive circuit 320 is disabled. When the first auxiliary drive circuit 320 is disabled, it is stopped regardless of the voltage level of the power supply voltage Vstop, and the first drive current Iaux1 is zero.

[0051] When the control signal CTRL includes an animation lighting instruction, multiple light-emitting elements 402_1 to 402_N light up with brightness and order corresponding to the specified animation.

[0052] When the control signal CTRL includes an instruction to illuminate the stop lamp (marker light), the marker light element 402_1 emits light with the brightness of a stop lamp.

[0053] - When the microcontroller 302 detects an abnormality in the drive module 300, the error signal ERR is asserted, and the first auxiliary drive circuit 320 is enabled. When a 12V power supply voltage Vstop is input as an instruction to light the stop lamp, the first auxiliary drive circuit 320 supplies a drive current Iaux1 to the indicator light element 402_1. As a result, the indicator light element 402_1 lights up with the brightness required for a stop lamp.

[0054] The above describes the operation of the lighting system 100. With this lighting system 100, when the drive module 300 is functioning normally, the dimming IC 310 can be used to drive multiple light-emitting elements 402_1 to 402_N. If a malfunction occurs in the drive module 300, the lighting animation will not be possible, but the first auxiliary drive circuit 320 can control the on / off state of the indicator light element 402_1, thereby maintaining the function of the stop lamp.

[0055] Figure 3 shows an example of the configuration of the lighting system 100. The lighting system 100 constitutes a rear lamp and includes a left rear lamp 200L, a center rear lamp 200C, and a right rear lamp 200R. The configuration of each lamp 200L, 200C, and 200R is as described above, but the microcontroller 302 is provided only in the center rear lamp 200C, and the left rear lamp 200L and the right rear lamp 200R operate under the control of the microcontroller 302. Note that the microcontroller 302 may be provided in the left rear lamp 200L, or in the right rear lamp 200R, or in each of the rear lamps 200L, 200C, and 200R.

[0056] Next, we will describe a modified version of the lighting system 100.

[0057] Figure 4 is a circuit diagram of a lighting system 100A according to modified example 1. The lighting system 100A includes a vehicle-side ECU 110 and a vehicle lighting fixture 200A. The vehicle lighting fixture 200 includes a light-emitting element module 400 and a drive module 300A.

[0058] The configuration of the light-emitting element module 400 is the same as that in Figure 1, and includes a plurality of N light-emitting elements 402_1 to 402_N. In this modified example, light-emitting elements 402_1 and 402_2 are indicator light elements, and their anodes are connected to each other. They serve as both a first and second indicator light. Here, the first indicator light is a stop lamp, and the second indicator light is a tail lamp.

[0059] The control signal CTRL (i) includes an instruction to light up the animation of the vehicle lighting fixture 200 and the specification of the type of animation, (ii) an instruction to light up the stop lamp which is the first indicator light, and (iii) an instruction to light up the tail lamp which is the second indicator light.

[0060] When the control signal CTRL includes an instruction to turn on the stop lamp, the microcontroller 302 operates at least one of the constant current drivers 312_1 and 312_2 so that the light-emitting elements 402_1 and 402_2 light up with the brightness of a stop lamp.

[0061] When the control signal CTRL includes an instruction to turn on the taillights, the microcontroller 302 operates at least one of the constant current drivers 312_1 and 312_2 so that the light-emitting elements 402_1 and 402_2 emit light at a brightness suitable for taillights.

[0062] When the taillights are on and the vehicle is in motion, pressing the brake pedal will trigger a signal to illuminate the stop lamps. In this case, the function of the stop lamps, which have higher brightness, takes precedence. When the control signal CTRL includes both a signal to illuminate the taillights and a signal to illuminate the stop lamps, the microcontroller 302 operates at least one of the constant current drivers 312_1 and 312_2 so that the light-emitting elements 402_1 and 402_2 emit light at the brightness required for stop lamps.

[0063] Alternatively, the vehicle's ECU may coordinate the taillights and brake lights. That is, when the driver presses the brake pedal while the taillights are on, a control signal CTRL containing only an instruction to turn on the brake lights may be sent to the drive module 300A.

[0064] The drive module 300A is supplied with a first power supply voltage Vstop, which instructs the stop lamps to light up, as well as a second power supply voltage Vtail, which instructs the tail lamps to light up. The second power supply voltage Vtail becomes 12V when instructing the tail lamps to light up.

[0065] The drive module 300A further includes a second auxiliary drive circuit 330 connected to the second terminal (anode) of the marker light elements 402_1 and 402_2. The second auxiliary drive circuit 330 is switchable between an enabled state and a disabled state, and becomes enabled when the error signal ERR is asserted. When the second auxiliary drive circuit 330 is enabled, it is configured to supply a drive current Iaux2 to the marker light elements 402_1 and 402_2 when a second power supply voltage Vtail, which instructs the lighting of the second marker light (tail lamp), is input.

[0066] As described above, the signals for illuminating the taillights and the brake lights may occur simultaneously, and therefore, both the first power supply voltage Vstop and the second power supply voltage Vtail may be supplied. In this case, the first auxiliary drive circuit 320 and the second auxiliary drive circuit 330 are configured so that the first auxiliary drive circuit 320 operates preferentially.

[0067] Specifically, the second auxiliary drive circuit 330 is connected to both the second power supply terminal TAIL, to which the second power supply voltage Vtail is supplied, and the first power supply terminal STOP, to which the first power supply voltage Vstop is supplied. The second auxiliary drive circuit 330 is configured to be disabled regardless of the error signal ERR when a high (12V) first power supply voltage Vstop is supplied.

[0068] Figure 5 is a circuit diagram showing an example configuration of the first auxiliary drive circuit 320 and the second auxiliary drive circuit 330. The configuration of the first auxiliary drive circuit 320 is the same as in Figure 2. The second auxiliary drive circuit 330 includes a third transistor M3, a fourth transistor M4, and resistors R4 to R6. The third transistor M3 and the drive resistor R4 are connected in series between the second power supply terminal TAIL and the anodes of the indicator light elements 402_1 and 402_2.

[0069] Resistor R5 is connected between the gate, which is the control electrode of the third transistor M3, and the second power supply terminal TAIL. The fourth transistor M4 is connected between the gate of the third transistor M3 and ground. Resistor R6 is inserted between the collector of the fourth transistor M4 and the gate of the third transistor M3.

[0070] Logic gate 332 controls the fourth transistor M4 based on the error signal ERR and the first power supply voltage Vstop. Specifically, when the first power supply voltage Vstop is high (12V), logic gate 332 outputs low, turning off the fourth transistor M4. When the first power supply voltage Vstop is low (0V) and the error signal ERR is asserted (low in this example), logic gate 332 outputs high, turning on the fourth transistor M4.

[0071] When the fourth transistor M4 is turned on, the gate of the third transistor M3 is connected to ground via resistor R6. In this state, when the second power supply voltage Vtail of 12V is supplied, a voltage of Vtail × R5 / (R5 + R6) is generated between the gate and source of the third transistor M3, and the third transistor M3 turns on. At this time, a drive current Iaux2 flows through the third transistor M3, which is inversely proportional to the resistance value of the drive resistor R4. Iaux2 = (Vtail - Vds - Vf) / R4 Vds is the drain-source voltage of the third transistor M3, and Vf is the forward voltage of the indicator light elements 402_1 and 402_2.

[0072] The above describes the configuration of the modified vehicle lighting device 200A. With this vehicle lighting device 200A, the indicator light elements 402_1 and 402_2 can be made to emit light as different indicator lights, namely a stop lamp and a tail lamp. Furthermore, if an abnormality occurs in the drive module 300, the indicator light elements 402_1 and 402_2 can be driven using the first auxiliary drive circuit 320 and the second auxiliary drive circuit 330, thereby maintaining the functions of the stop lamp and tail lamp.

[0073] In Figure 4, two light-emitting elements 402_1 and 402_2 are used as indicator light elements, but it is also possible to use only one light-emitting element as an indicator light element.

[0074] Figure 6 is a circuit diagram of the lighting system 100B according to the modified example 2. The lighting system 100A includes a vehicle-side ECU 110 and a vehicle lighting fixture 200B. The vehicle lighting fixture 200 includes a light-emitting element module 400 and a drive module 300B.

[0075] Modification 1 and Modification 2 are similar in that the vehicle lighting device 200B has the function of two marker lights, but they differ in that separate light-emitting elements 402_1 and 402_2 are assigned to the two marker lights. That is, light-emitting element 402_1 functions as the first marker light, and light-emitting element 402_2 functions as the second marker light.

[0076] The output of the first auxiliary drive circuit 320 is connected to the anode of only the first indicator light element 402_1, and the output of the second auxiliary drive circuit 330 is connected to the anode of only the first indicator light element 402_2.

[0077] The present disclosure has been described above based on embodiments. These embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their components and processing processes, and that such modifications are also within the scope of the present disclosure.

[0078] This disclosure relates to vehicle lighting equipment.

[0079] 100 Lighting system, 110 Vehicle-side ECU, 200 Vehicle lighting fixture, 300 Drive module, 302 Microcontroller, 304 Power supply circuit, 310 Dimming IC, 312 Constant current driver, 314 Control logic, 320 First auxiliary drive circuit, M1 First transistor, M2 Second transistor, R1 Drive resistor, R2 Resistor, R3 Resistor, 400 Light-emitting element module, 402 Light-emitting element, 330 Second auxiliary drive circuit.

Claims

1. A vehicle lighting device comprising: a plurality of light-emitting elements whose first ends are connected in common; a dimming circuit having a plurality of output terminals, each output terminal being connected to the second end of the corresponding light-emitting element and capable of individually controlling the current flowing through the plurality of light-emitting elements; a microcontroller that communicates with a vehicle-side control device and controls the dimming circuit based on instructions from the vehicle-side control device, and asserts an error signal when it detects an abnormality; and a first auxiliary drive circuit connected to the second end of the marker light element, where a portion of the plurality of light-emitting elements that functions as a first marker light is referred to as a marker light element, wherein the first auxiliary drive circuit is switchable between an enabled state and a disabled state, enters the enabled state when the error signal is asserted, and is configured to supply a drive current to the marker light element when a first power supply voltage instructing the lighting of the first marker light is input in the enabled state.

2. The vehicle lighting device according to claim 1, wherein the indicator light element also functions as a second indicator light, and further comprises a second auxiliary drive circuit connected to the second end of the indicator light element, the second auxiliary drive circuit is switchable between an enabled state and a disabled state, becomes enabled when the error signal is asserted, and is configured to supply a drive current to the indicator light element when a second power supply voltage instructing the lighting of the second indicator light is input in the enabled state.

3. The vehicle lighting device according to claim 2, characterized in that the second auxiliary drive circuit is disabled when the first power supply voltage is input, regardless of the error signal.

4. The vehicle lighting device according to claim 2 or 3, characterized in that the first indicator light is a stop lamp and the second indicator light is a tail lamp.

5. The vehicle lighting device according to any one of claims 1 to 3, characterized in that the first auxiliary drive circuit includes a first P-type transistor and a drive resistor connected in series between a first power terminal to which the first power supply voltage is input and the indicator light element, and a second transistor connected between the control electrode of the first transistor and ground, which switches on and off in response to the error signal.

6. The vehicle lighting device according to any one of claims 1 to 3, characterized in that, among the plurality of light-emitting elements, the light-emitting elements other than the indicator light elements are used for animation effects.

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