Vehicle lamp control device

Abstract

The present invention solves the technical problem occurring during lighting control of a light-emitting element constituting a vehicle lamp. The vehicle lamp control device includes, for example, a first constant current source that supplies a constant current to a light emitting element used in a vehicle lamp; a resistance circuit connected in series with the light emitting element and the first constant current source; a current value control circuit that controls the value of the current of the first constant current source in accordance with a lighting state instruction indicating the lighting state of the light-emitting element; and a resistance value control circuit that changes the value of the resistance of the resistance circuit so as to suppress a change in the value of the voltage applied to the first constant current source when the value of the current supplied to the light-emitting element changes. Furthermore, the vehicle lamp control device is provided with a second constant current source that supplies a current corresponding to the lighting state instruction, and the resistance value control circuit changes the value of the resistance of the resistance circuit in accordance with the value of the current supplied by the second constant current source.

Description

Technical Field

[0001] The present invention relates to a control device for vehicle lamps. Background Art

[0002] This application claims the priority of Japanese Patent Applications No. 2022-199511, No. 2022-199512, and No. 2022-199513, all filed on December 14, 2022, the disclosures of which are incorporated herein by reference in their entirety.

[0003] In recent years, there has been an increasing market demand for rich expressions such as animation display through lamps (hereinafter referred to as "vehicle lamps") mounted on vehicles, such as headlights and taillights, and for high-density information transmission (communication) with external objects and people (following vehicles, oncoming vehicles, drivers of other vehicles, pedestrians, etc.). On the other hand, with the diversification and complication of the expressions required for vehicle lamps, efforts are being made to promote the unification and commonization of the structures for lighting control and the efficiency of the software management system using structures such as OTA (Over The Air).

[0004] For example, Patent Document 1 describes a vehicle lamp configured for the purpose of comprehensively controlling multiple lamps. Additionally, for example, Patent Document 2 describes a vehicle control device (electronic control unit) configured to update the software stored in an ECU (Electronic Control Unit) mounted on a vehicle via OTA.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-49515

[0008] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2019-144669

[0009] Patent Document 3: International Publication No. 2019 / 098138 Summary of the Invention

[0010] (I) Technical Problems to be Solved

[0011] However, when using a light-emitting element that is lit based on constant current control, such as an LED (Light Emitting Diode), as a light source to achieve rich expressions such as animation display, it is necessary to change the value of the current (constant current) flowing from the constant current source to the light-emitting element according to the content of the expression. In addition, in the case of software that controls the lighting of the light-emitting element by OTA update or the like at any time, the value of the current supplied from the constant current source to the light-emitting element may change before and after the software update.

[0012] Here, if the value of the current (constant current) supplied from the constant current source to the light-emitting element is changed in this way, the value of the voltage applied to the constant current source (hereinafter referred to as "Vk".) may sometimes change. Therefore, there is a possibility that the power consumption and heat generation increase due to the excessive value of the voltage (Vk) applied to the constant current source, or a possibility that the light-emitting element does not light up due to the value of the voltage (Vk) applied to the constant current source being lower than the value required for the normal operation of the constant current source (too small) (for example, refer to Patent Document 3). Therefore, when realizing rich expressions based on vehicle lamps and making the lighting control structure more efficient, it is necessary to take some countermeasures against such technical problems.

[0013] In addition, the change in the current flowing through the light-emitting element may be the main cause of the temperature change of the light-emitting element. In addition, the temperature of the light-emitting element also changes according to the environment in which the vehicle is located, the self-heating of the light-emitting element, etc.

[0014] Here, when the temperature of the light-emitting element changes and the value of the voltage (hereinafter referred to as "Vk".) applied to the constant current source changes according to the temperature characteristics of the light-emitting element, there is a possibility that the power consumption and heat generation increase due to the excessive value of the voltage (Vk) applied to the constant current source, or a possibility that the light-emitting element does not light up due to the value of the voltage (Vk) applied to the constant current source being lower than the value required for the normal operation of the constant current source (too small) (for example, refer to Patent Document 3). Therefore, when controlling the lighting of the light-emitting element that constitutes a vehicle lamp, it is necessary to take some countermeasures against such technical problems.

[0015] In addition, in a vehicle lamp that uses a light-emitting element that is lit based on constant current control, such as an LED (Light Emitting Diode), as a light source, due to a short circuit of the light-emitting element, the value of the current flowing through the light-emitting element increases, and as a result, the voltage applied to the constant current source increases, and there is a possibility of causing an increase in power consumption and heat generation (for example, refer to Patent Document 3).

[0016] In the above-mentioned Patent Document 1, the vehicle lamp described controls the lighting states of a plurality of light sources according to the states of a plurality of lighting requests through comprehensive software processing by a signal processing device, but does not address the above-mentioned technical problem. In addition, the technology described in Patent Document 2 is configured for the purpose of eliminating the limitation of the timing for executing the update process of the program, and does not describe the above-mentioned technical problem.

[0017] The present invention has been completed in view of such a background, and an object thereof is to provide a vehicle lamp control device capable of solving the technical problems that occur when controlling the lighting of light-emitting elements constituting a vehicle lamp.

[0018] (2) Technical Solution

[0019] One aspect of the present invention for achieving the above object is a vehicle lamp control device, which includes: a first constant current source that supplies a constant current to a light-emitting element used in a vehicle lamp; a resistance circuit that is connected in series with the light-emitting element and the first constant current source; a current value control circuit that controls the value of the current of the first constant current source according to a lighting state indication indicating the lighting state of the light-emitting element; and a resistance value control circuit that changes the value of the resistance of the resistance circuit to suppress a change in the value of the voltage applied to the first constant current source when the value of the current supplied to the light-emitting element changes.

[0020] Thereby, it is possible to solve the technical problems that occur when controlling the lighting of light-emitting elements constituting a vehicle lamp.

[0021] In addition, another aspect of the present invention for achieving the above object is a vehicle lamp control device, which includes: a first constant current source that supplies a constant current to a light-emitting element used in a vehicle lamp; a resistance circuit that is connected in series with the light-emitting element and the first constant current source; a current value control circuit that controls the value of the current of the first constant current source; and a resistance value control circuit that changes the value of the resistance of the resistance circuit to suppress a change in the value of the voltage applied to the first constant current source when the temperature around the light-emitting element changes.

[0022] Thereby, it is possible to solve the technical problems that occur when controlling the lighting of light-emitting elements constituting a vehicle lamp.

[0023] Another solution of the present invention for achieving the above object is a vehicle lamp control device, which includes: a first constant current source that supplies a constant current to a light-emitting element used in a vehicle lamp; a resistor circuit that is connected in series with the light-emitting element and the first constant current source; a current value control circuit that controls the current value of the first constant current source; and a resistance value control circuit that changes the resistance value of the resistor circuit to suppress the change in the voltage value applied to the first constant current source when the light-emitting element is short-circuited.

[0024] Thus, the technical problem generated when a short circuit occurs in the light-emitting element constituting the vehicle lamp can be solved.

[0025] In addition, the technical problem disclosed in this application and its solution method are clarified through the specific implementation part and the drawings of the specification.

[0026] (III) Beneficial Effects

[0027] According to the present invention, the technical problem generated when controlling the lighting of the light-emitting element constituting the vehicle lamp can be solved. Brief Description of the Drawings

[0028] Figure 1 It is a diagram showing the schematic structure of an electronic control system mounted on a vehicle.

[0029] Figure 2 It is a diagram for explaining the structure of the vehicle lamp control device.

[0030] Figure 3 It is a diagram showing the structure of the rear lamp lighting control circuit and the LED substrate.

[0031] Figure 4A It is a diagram for explaining the technical problem in the lighting control of an LED driven by a constant current.

[0032] Figure 4B It is a diagram for explaining the technical problem in the lighting control of an LED driven by a constant current.

[0033] Figure 5A It is a diagram showing an example of the vehicle lamp control device of the present embodiment.

[0034] Figure 5B It is a diagram showing an example of the vehicle lamp control device of the present embodiment.

[0035] Figure 5C It is a diagram showing an example of the vehicle lamp control device of the present embodiment.

[0036] Figure 5D It is a diagram showing an example of the vehicle lamp control device of the present embodiment.

[0037] Figure 5E This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0038] Figure 6A This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0039] Figure 6B This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0040] Figure 6C This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0041] Figure 6D This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0042] Figure 7 This is a diagram showing an example of a current source.

[0043] Figure 8A This is a diagram for explaining technical problems in the lighting control of an LED driven by a constant current.

[0044] Figure 8B This is a diagram for explaining technical problems in the lighting control of an LED driven by a constant current.

[0045] Figure 9A This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0046] Figure 9B This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0047] Figure 9C This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0048] Figure 9D This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0049] Figure 9E This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0050] Figure 10A This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0051] Figure 10B This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0052] Figure 10C This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0053] Figure 10D This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0054] Figure 11 This is a diagram showing an example of a current source.

[0055] Figure 12 This is a diagram for explaining a technical problem in the lighting control of an LED driven by a constant current.

[0056] Figure 13A This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0057] Figure 13B This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0058] Figure 13C This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0059] Figure 13D This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0060] Figure 13E This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0061] Figure 14A This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0062] Figure 14B This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0063] Figure 14C This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0064] Figure 14D This is a diagram showing an example of the vehicle lamp control device according to the present embodiment.

[0065] Figure 15 This is a diagram showing an example of a current source. Detailed Embodiment

[0066] Hereinafter, the detailed embodiment will be described with reference to the accompanying drawings of the specification. In addition, in the following description, the same or similar structures may be denoted by the same reference numerals and repeated descriptions may be omitted. Further, in the following description, when it is necessary to distinguish between the same type of structures, a suffix (number, letter, etc.) may sometimes be added after the reference numeral that collectively refers to the structure.

[0067] In Figure 1The schematic configuration of the electronic control system 50 mounted on the vehicle 2 is shown as an embodiment of the present invention. The illustrated electronic control system 50 includes various ECUs (Electronic Control Units) that control each part of the vehicle 2 (power train system ECU, chassis system ECU, body system ECU, multimedia system ECU, ADAS (Advanced Driver-Assistance Systems) ECU, etc.). Each ECU includes a processor (CPU (Central Processing Unit), MPU (MicroProcessing Unit), etc.), a storage device (memory, SSD, hard disk, removable recording medium, etc.), and a communication device (CAN transceiver, etc.), and functions as an information processing device (computer). In addition, in this figure, a configuration centered on the body system ECU among the various ECUs mounted on the vehicle 2 is illustrated.

[0068] As shown in this figure, the electronic control system 50 includes a central ECU 21 (first information processing device), a front ECU 22 (second information processing device), and a rear ECU 23 (second information processing device). The electronic control system 50 controls, for example, the lamps of the vehicle 2 such as the headlamp 30 and the rear lamp 40 (hereinafter referred to as "vehicle lamps").

[0069] The central ECU 21 is communicably connected to the front ECU 22 and the rear ECU 23, and performs overall control of the front ECU 22 and the rear ECU 23. The central ECU 21 operates as a master device, for example, and the front ECU 22 and the rear ECU 23 operate as slave devices, for example.

[0070] The front ECU 22 is communicably connected to the headlamp 30. In addition, the rear ECU 23 is communicably connected to the rear lamp 40. The headlamp 30 includes, for example, elements 3 such as a headlamp, a parking lamp, a fog lamp, a DRL (Daytime Running Lamp), a CLL (Clearance Lamp), a Lo / Hi light control mechanism, an ADB (Adaptive Driving Beam), and an automatic leveling system. The rear lamp 40 includes, for example, elements 4 such as a turn signal lamp, a tail lamp, a brake lamp, and a reverse lamp.

[0071] The central ECU 21 sends indication information on the lighting method (lighting mode) (hereinafter referred to as "lighting method indication") to the front ECU 22 and the rear ECU 23. In addition, the central ECU 21 obtains the respective operation information from the front ECU 22 and the rear ECU 23, and provides the obtained operation information to the outside of the vehicle 2.

[0072] In addition, communication (wireless communication or wired communication (e.g., OTA (Over The Air) communication)) is performed between the central ECU 21 and a device outside the vehicle 2 (e.g., the operator terminal 5). The central ECU 21 obtains update information (including update differences) of the software (including firmware) stored in the front ECU 22 and the rear ECU 23 by communicating with the external device. The above-mentioned software includes, for example, software for realizing various expressions such as animation display through vehicle lamps (e.g., the execution code of a program for generating the lighting state indication described later).

[0073] As the communication methods used in the communication between the central ECU 21, the rear ECU 23, and the rear lamp 40, there are CAN (Controller Area Network), CAN FD (CAN Flexible Data rate), LIN (Local Interconnect Network), FlexRay (registered trademark), Ethernet (registered trademark), various serial communication methods, etc., but the communication methods are not limited to these methods.

[0074] Here, as the structure of the lighting control of the light-emitting element that constitutes the light source of the vehicle lamp, it is the mainstream that the overall ECU such as the central ECU 21 individually sends control instructions to the control devices (microcomputers, etc.) provided in each vehicle lamp, and each control device controls the drive circuit (drive IC, etc.) to perform the lighting control of the light-emitting element.

[0075] In contrast, in Figure 1 the shown electronic control system 50, the ECUs such as the front ECU 22 and the rear ECU 23, which are positioned as subordinates of the central ECU 21 and are between the central ECU 21 and the vehicle lamp, send control instructions to the drive circuit of the vehicle lamp to perform the lighting control of the light-emitting element. Therefore, the load on the central ECU 21 is reduced, and in addition, lighting control with a high load such as animation display can be performed by the front ECU 22 and the rear ECU 23.

[0076] In addition, in Figure 1 the shown electronic control system 50, the lighting control of the light-emitting element performed by the front ECU 22 and the rear ECU 23 is mainly software-based. Therefore, there is no need to provide hardware dedicated to specific functions (turn signal display, tail display, brake display, reverse display, etc.) in the vehicle lamp, and simplification of the structure, improvement of productivity, reduction of maintenance burden, etc. can be achieved.

[0077] In addition, in Figure 1In the electronic control system 50 shown, the software for realizing the functions of the front ECU 22 and the rear ECU 23 can be updated at any time, and the lighting method (lighting mode) of the vehicle lamp can be easily and quickly changed without changing the hardware. Therefore, various requirements for the lighting method of the vehicle lamp such as animation display can be flexibly and quickly responded to.

[0078] Figure 2 Yes Description Figure 1 The block diagram of the electronic control system 50 shown in FIG. 1 is a block diagram focusing on the structure around the rear ECU 23 (hereinafter referred to as the "vehicle lamp control device 1"). In addition, the figure illustrates a structure assuming that the rear ECU 23 performs lighting control of the rear lamp 40 as the element 4 provided on the rear side of the vehicle 2.

[0079] As shown in the figure, the rear light 40 includes a rear light lighting control circuit 41 and an LED substrate 42. Among them, the rear light lighting control circuit 41 is communicatively connected to the rear ECU 23. In addition, the rear light lighting control circuit 41 and the LED substrate 42 are connected via a communication line (CAN, LIN, etc.) or a signal line (direct line (Japanese: ジカ線) (direct wiring)). On the other hand, one or more light-emitting elements constituting the light source of the vehicle lamp are installed on the LED substrate 42. In addition, in this embodiment, the case where the light-emitting element is an LED (Light-Emitting Diode) is used as an example for explanation, but as long as the light-emitting element is a light-emitting element that performs lighting control based on constant current drive, the light-emitting element may also be other types of light-emitting elements (for example, laser diodes, organic EL (OEL: Organic Electro-Luminescence), etc.).

[0080] The rear ECU 23, the rear lamp lighting control circuit 41 and the LED substrate 42 are supplied with power from a battery 6 (power storage device) mounted on the vehicle 2. The rear lamp lighting control circuit 41 and the LED substrate 42 are housed in a housing (casing) of a rear lamp 40 provided on the vehicle 2, for example.

[0081] The rear ECU 23, for example, generates an indication of a lighting state corresponding to the lighting method indication sent from the central ECU 21 (hereinafter referred to as a "lighting state indication") and sends it to the rear light lighting control circuit 41. The rear light lighting control circuit 41 performs lighting control of the LED mounted on the LED substrate 42 according to the lighting state indication sent from the rear ECU 23. The lighting state indication includes, for example, information (parameters) specifying the lighting state of the LED, such as the value of the current flowing through the LED, the timing of lighting the LED, and the speed of changing the brightness of the LED (for example, the time change of the duty ratio when PWM control is performed).

[0082] Figure 3 This is a diagram showing the rear lamp lighting control circuit 41 and the LED substrate 42 of a general vehicle lamp control device 1. As shown in this diagram, the rear lamp lighting control circuit 41 includes a voltage source 411 and a current source 412. Among them, the voltage source 411 applies a driving voltage to one or more LEDs 405 mounted on the LED substrate 42, and the current source 412 supplies a constant current to the LEDs 405.

[0083] Among them, the voltage source 411 is a device that generates a DC voltage of a specified magnitude based on the power supplied from the battery 6, and is constituted by, for example, a DC / DC converter (step-down converter, step-up converter, buck-boost converter, etc.).

[0084] The current source 412 is constituted by, for example, an integrated circuit such as a sink driver IC (hereinafter also referred to as "driver IC"). The current source 412 includes a plurality of constant current sources 4121 capable of individually (independently) controlling the current (constant current) according to the lighting state indication.

[0085] One or more LED columns 400 are provided on the LED substrate 42. One LED column 400 includes one or more LEDs 405 connected in series. A DC voltage of a specified magnitude is applied from the voltage source 411 to the LED column 400. One LED column 400 is connected to one of the plurality of constant current sources 4121 provided in the current source 412. The LED column 400 includes one or more resistance elements 422 for adjusting the voltage applied to the constant current source 4121. In this diagram, a case where one resistance element 422 of the LED column 400 is connected in series with two LEDs 405 is illustrated.

[0086] [First Embodiment]

[0087] Here, in the Figure 3 structure shown, for example, if the lighting state of the LED 405 changes according to the lighting state indication from the rear ECU 23, the value of the current flowing through the LED 405 changes, and the voltage applied to the constant current source 4121 (hereinafter referred to as "Vk") changes. Therefore, there is a possibility that the power consumption and heat generation increase due to the excessive voltage (Vk) applied to the constant current source, or a possibility that the LED 405 does not light due to the excessive small voltage (Vk) applied to the constant current source. Below, with reference to Figure 4A and Figure 4B this situation will be specifically described.

[0088] Next, as an example, consider a case where the brightness of the LED 405 in the LED column 400 is switched from a brightly lit state to a dimly lit state according to the lighting state indication sent from the rear ECU 23. As a case where such a switch is made, for example, there is a case where the LED 405 that has been brightly lit as a brake light is to be dimly lit as a tail light. Hereinafter, the value of the current flowing through the LED 405 when it is brightly lit is set as Ia, and the value of the current flowing through the LED 405 when it is dimly lit is set as Ib (< Ia).

[0089] Here, for example, as Figure 4A shown, consider a case where the resistance value of the resistance element 422 is designed based on Ia, that is, a case where the resistance value of the resistance element 422 is designed in such a way that the value of the voltage (Vk) applied to the constant current source 4121 when a current of Ia flows through the LED column 400 is appropriate. In this case, as Figure 4A shown in (a) of, when the LED 405 is brightly lit, that is, when the value of the current of the LED 405 is Ia, the voltage drop across the resistance element 422 is appropriate, and the value of the voltage (Vk) applied to the constant current source 4121 is also appropriate. On the other hand, as Figure 4A shown in (b) of, when the LED 405 is dimly lit, that is, when the value of the current of the LED 405 is Ib, the voltage drop across the resistance element 422 decreases. As a result, the value of the voltage (Vk) applied to the constant current source 4121 rises (excessively), leading to an increase in power consumption and heat generation.

[0090] In addition, for example, as Figure 4B shown, consider a case where the resistance value of the resistance element 422 is designed based on Ib, that is, a case where the resistance value of the resistance element 422 is designed in such a way that the voltage applied to the constant current source 4121 when a current of Ib flows through the LED 405 is appropriate. In this case, as Figure 4B shown in (a) of, when the LED 405 is dimly lit, that is, when the value of the current flowing through the LED 405 is Ib, the voltage drop across the resistance element 422 is appropriate, and the voltage applied to the constant current source 4121 is also appropriate. On the other hand, as Figure 4B shown in (b) of, when the LED 405 is brightly lit, that is, when the current flowing through the LED 405 is Ia, the voltage drop across the resistance element 422 increases, and the value of the voltage (Vk) applied to the constant current source 4121 decreases. Moreover, when the value of the voltage (Vk) is lower than the lower limit value of the voltage required for the normal operation of the constant current source 4121 (in the case of being too small), the LED 405 does not light up.

[0091] Thus, when the value of the resistance element 422 is fixed, the lighting state of the LED 405 is switched according to the lighting state instruction sent from the rear ECU 23, which may lead to an increase in the power consumption and heat generation of the constant current source 4121 and the non-lighting of the LED 405.

[0092] Therefore, in the present embodiment, by providing a resistance circuit (hereinafter referred to as "resistance circuit 420") capable of changing the resistance value in the LED column 400, such a technical problem is solved. Hereinafter, some structures of the vehicle lamp control device 1 of the present embodiment will be specifically described.

[0093] Figure 5A It is a structural example of the vehicle lamp control device 1 of the present embodiment. In the illustrated vehicle lamp control device 1, a resistance circuit 420 is provided in series with the LED 405 constituting the LED column 400, and a circuit (hereinafter referred to as "resistance value control circuit 440") for controlling the resistance value of the resistance circuit 420 is provided. The resistance circuit 420 includes: a resistance element 422a; a resistance element 422b connected in parallel with the resistance element 422a; and a switch 423 connected in series with the resistance element 422b and for turning on and off the connection with the LED 405. The specific structure of the resistance value control circuit 440 will be described later.

[0094] In the example of this figure, the on / off control of the switch 423 is performed by changing the current value of another constant current source 4121 (hereinafter also referred to as "second constant current source 4121b") different from the constant current source 4121 (hereinafter also referred to as "first constant current source 4121a") that supplies current to the LED column 400 among the plurality of constant current sources 4121 provided in the current source 412.

[0095] The current source 412 controls the current value of the second constant current source 4121b according to the lighting state instruction from the rear ECU 23, thereby controlling the on / off of the switch 423 and switching the resistance value of the resistance circuit 420.

[0096] For example, when the LED 405 is brightly lit (when the current value of the LED 405 increases) according to the lighting state instruction from the rear ECU 23, the current source 412 changes the current value of the second constant current source 4121b, thereby turning off the switch 423 and increasing the resistance value of the resistance circuit 420 (increasing the voltage drop across the resistance circuit 420) to prevent the voltage applied to the first constant current source 4121a from rising.

[0097] Further, for example, when the LED 405 is dimly lit according to the lighting state indication from the rear ECU 23 (when the value of the current through the LED 405 becomes smaller), the current source 412 changes the value of the current of the second constant current source 4121b to turn on the switch 423 and reduce the resistance value of the resistor circuit 420 (reduce the voltage drop across the resistor circuit 420), thereby preventing a decrease in the voltage applied to the first constant current source 4121a.

[0098] Thus, in the illustrated vehicle lighting control device 1, the resistance value of the resistor circuit 420 is changed to suppress a change in the value of the voltage applied to the first constant current source 4121a due to a change in the value of the current supplied to the LED 405 according to the lighting state indication from the rear ECU 23. Therefore, for example, even when the lighting of the light source (LED 405) is controlled in various ways such as by animation, the value of the voltage applied to the first constant current source 4121a can be maintained within a specified range, and an increase in power consumption and heat generation due to an excessive value of the voltage (Vk) applied to the first constant current source 4121a can be prevented. In addition, the non - lighting of the LED 405 due to the value of the voltage (Vk) applied to the first constant current source 4121a being lower than the value required for the normal operation of the first constant current source 4121a (being too small) can be prevented.

[0099] Further, in the illustrated vehicle lighting control device 1, the current source 412 changes the value of the current of the second constant current source 4121b, which is different from the first constant current source 4121a, among the plurality of constant current sources 4121 included in the current source 412. That is, the resistance value of the resistor circuit 420 is changed by using the second constant current source 4121b, which is one of the constant current sources 4121 of the current source 412. Therefore, a structure for controlling the resistance value of the resistor circuit 420 according to the lighting state indication can be realized with a simple structure.

[0100] In addition, a change in the value of the current supplied from the constant current source 4121 to the LED 405 may also occur when the software stored in the rear ECU 23 for implementing the process of generating the lighting state indication is updated based on the information received by the rear ECU 23 from the central ECU 21. Even in this case, the value of the voltage (Vk) applied to the first constant current source 4121a can be maintained within a specified range.

[0101] Figure 5B is constituted by using transistors Figure 5AThe case of the switch 423 shown. In this example, the emitter of the transistor is connected to the voltage source 411, and the collector is connected to the resistance element 422b. In addition, the base of the transistor is connected to the second constant current source 4121b via the resistance element 422c and is connected to the voltage source 411 via the resistance element 422d. A voltage determined by the following values is applied to the base of the transistor: the value of the voltage of the voltage source 411, the value of the current supplied from the second constant current source 4121b, the resistance value of the resistance element 422c, and the resistance value of the resistance element 422d. That is, in the vehicle lamp control device 1 shown in this figure, the aforementioned resistance value control circuit 440 is composed of the resistance element 422c and the resistance element 422d.

[0102] In addition, in Figure 5B this example, the switch 423 is constituted by a PNP-type transistor. Therefore, when the value of the current supplied from the second constant current source 4121b is small and the voltage drop at the resistance element 422d is below a specified value, the switch 423 is turned off, and when the value of the above current is large and the voltage drop at the resistance element 422d exceeds the specified value, the switch 423 is turned on.

[0103] In addition, the switch 423 can also be constituted by other types of elements such as a field effect transistor (FET: Field-Effect Transistor), for example. When the switch 423 is constituted by a field effect transistor, the drain is connected to the voltage source 411, and the source is connected to the resistance element 422b. In addition, for the gate, it is connected to the second constant current source 4121b via the resistance element 422c and is connected to the voltage source 411 via the resistance element 422d.

[0104] In this way, the on / off of the switch 423 can be controlled by changing the value of the current supplied from the second constant current source 4121b. In addition, the structure for controlling the resistance value of the lighting state indication control resistance circuit 420 can be simply constituted using the resistance element and the switch 423.

[0105] Figure 5C is another structural example of the vehicle lamp control device 1. In this example, the diode 424 connected in the forward direction to the LED column 400 is used to replace Figure 5BThe resistor element 422b connected in series with the switch 423 of the resistor circuit 420. When the switch 423 is off, the resistance value of the resistor circuit 420 becomes the resistance value of the resistor element 422a. Further, when the switch 423 is on, the resistance value of this resistor circuit 420 becomes zero. In addition, in order to make the resistance value of the resistor circuit 420 a specified value other than zero even when the switch 423 is on, for example, a resistor element may be connected in series with the switch 423. The specific structure is omitted in this figure, but as the resistance value control circuit 440 in this resistor circuit 420, for example, the circuit shown in Figure 5B (a circuit composed of the resistor element 422c and the resistor element 422d) can be used.

[0106] Figure 5D is another structural example of the vehicle lamp control device 1. In this example, the resistance value of the resistor circuit 420 connected to the LED column 400 is changed by the variable resistor element 522a connected in series with the LED column 400. In this example, as the variable resistor element 522a, a potentiometer (hereinafter referred to as "analog potentiometer") of a type that sets the resistance value by an analog value (voltage value) is used.

[0107] As shown in this figure, the analog value input terminal 5221 of the variable resistor element 522a is connected to the second constant current source 4121b. A voltage obtained by dividing the voltage of the voltage source 411 by the resistance value of the resistor element 522b and the resistance value of the resistor element 522c is applied to the input terminal 5221. The resistance value of the resistor element 522b and the resistance value of the resistor element 522c are set, for example, according to the range of the resistance value required for the resistor circuit 420. In the case of this circuit, the resistance value control circuit 440 is composed of the resistor element 522b and the resistor element 522c.

[0108] Similarly to Figure 5D the vehicle lamp control device 1 shown in Figure 5E is a case where the resistance value of the resistor circuit 420 connected to the LED column 400 is changed by the variable resistor element 522a connected in series with the LED column 400. In this example, as the variable resistor element 522a, a potentiometer (hereinafter referred to as "digital potentiometer") of a type that sets the resistance value by inputting a digital value specifying the resistance value is used.

[0109] In this example, the analog voltage value divided by the resistor element 522b and the resistor element 522c is converted into a digital value by the A / D conversion circuit 525, and the converted digital value is input to the digital value input terminal 5222 of the variable resistor element 522a. In the case of this circuit, the resistance value control circuit 440 is composed of the resistor element 522b, the resistor element 522c, and the A / D conversion circuit 525.

[0110] Thus, a structure that changes the resistance value of the resistance element 422 connected to the LED column 400 according to the lighting state indication from the rear ECU 23 can be simply configured using a variable resistance element such as an analog potentiometer or a digital potentiometer. In addition, when a digital potentiometer is used as the variable resistance element 522a, the advantages of the digital potentiometer (high precision, high resolution, small size, high stability, long life, high reliability, etc.) can be enjoyed.

[0111] In addition, in the structure described above Figures 5A - 5C shown, since the resistance values of the resistance element 422a and the resistance element 422b are fixed, the resistance value of the resistance circuit 420 can only be switched stepwise (discontinuously). In contrast, in Figure 5D or Figure 5E shown structures, since a variable resistance element is used, the resistance value of the resistance circuit 420 can be changed continuously. Therefore, the value of the resistance circuit 420 can be finely controlled. For example, in the case of finely controlling the lighting state of the light-emitting element such as in the case of performing an animation display, the resistance value of the resistance circuit 420 can follow the change in the lighting state of the light-emitting element with high precision.

[0112] Figures 6A - 6D is another structural example of the vehicle lamp control device 1. In the vehicle lamp control device 1 shown in Figures 5A - 5E , the resistance value of the resistance circuit 420 is changed by the constant current source 4121 (second constant current source 4121b) of the current source 412. In contrast, in the vehicle lamp control device 1 shown in Figures 6A - 6D , the LED substrate 42 is provided with a communication function, the LED substrate 42 receives the lighting state indication from the rear ECU 23, and the LED substrate 42 controls a switch according to the received lighting state indication to change the resistance value of the resistance circuit 420.

[0113] Figure 6A The resistance circuit 420 in the vehicle lamp control device 1 shown in Figure 5A or Figure 5B is, for example, the same as that shown in. In this example, on the LED substrate 42, a communication circuit 431 (such as a CAN transceiver) for receiving the lighting state indication, a decoder circuit 432 for decoding the lighting state indication, a D / A conversion circuit 433 for converting the decoded digital value into an analog value, and a conduction-disconnection control circuit 434 for controlling the switch 423 based on the converted analog value are provided.

[0114] In addition, the lighting state instruction received by the communication circuit 431 includes, for example, a parameter for instructing to turn on or off the switch 423. The D / A conversion circuit 433 generates an analog value corresponding to the value of the above parameter and inputs it to the on / off control circuit 434. In the example of the figure, the resistance value control circuit 440 is composed of the communication circuit 431, the decoder circuit 432, the D / A conversion circuit 433, and the on / off control circuit 434.

[0115] Thus, the structure of changing the resistance value of the resistor circuit 420 according to the lighting state instruction from the rear ECU 23 can also be realized by the structure shown in the figure. In addition, in the case of such a structure, the above structure can be realized without consuming the resources (constant current source) of the current source 412.

[0116] exist Figure 6B In, with Figure 5C In the case of the vehicle lamp control device 1 shown in FIG. 1 , the diode 424 connected in the forward direction is used to replace the Figure 6A In this example, the resistance value of the resistance circuit 420 when the switch 423 is turned on can be made substantially zero. In addition, for example, by connecting the resistance element 422b having a resistance value greater than zero in series with the switch 423, the resistance value of the resistance circuit 420 when the switch 423 is turned on can be made a prescribed value greater than zero. In the example of the figure, the resistance value control circuit 440 is composed of a communication circuit 431, a decoder circuit 432, a D / A conversion circuit 433, and an on / off control circuit 434.

[0117] exist Figure 6C as well as Figure 6D In, with Figure 5D as well as Figure 5E Similarly, in the illustrated vehicle lamp control device 1 , the resistance circuit 420 is configured using the variable resistance element 522 a .

[0118] Figure 6C is with Figure 5D Similarly, an analog potentiometer is used as the variable resistance element 522a. In this example, the LED substrate 42 is provided with: a communication circuit 431 (CAN transceiver, etc.) for receiving the lighting state indication; a decoder circuit 432 for decoding the lighting state indication; and a D / A conversion circuit 433 for converting the decoded digital value into an analog value and inputting it to the analog value input terminal 5221 of the variable resistance element 522a. In the example of the figure, the resistance value control circuit 440 is composed of the communication circuit 431, the decoder circuit 432 and the D / A conversion circuit 433.

[0119] Figure 6D is with Figure 5ESimilarly, in the case where a digital potentiometer is used as the variable resistance element 522a. In this example, on the LED substrate 42, a communication circuit 431 (such as a CAN transceiver) that receives the lighting state indication is provided; and a decoder circuit 432 that decodes the lighting state indication and inputs the decoded digital value to the input terminal 5222 of the digital value of the variable resistance element 522a. In the example of this figure, the resistance value control circuit 440 is composed of the communication circuit 431 and the decoder circuit 432.

[0120] As described above, the vehicle lamp control device 1 of the present embodiment changes the resistance value of the resistance circuit 420 to suppress the change in the voltage value (Vk) applied to the first constant current source 4121a when the value of the current supplied to the LED 405 changes. Therefore, for example, even when the lighting control of the LED 405 is performed in various ways such as by animation, the voltage value applied to the first constant current source 4121a can be maintained within a specified range. Thus, it is possible to prevent an increase in power consumption and heat generation due to an excessive voltage value (Vk) applied to the first constant current source 4121a, and the non-illumination of the LED 405 due to the voltage value (Vk) applied to the first constant current source 4121a being lower than the value required for the normal operation of the first constant current source 4121a (too small).

[0121] Figure 7 It is a block diagram showing a structural example of the current source 412. The illustrated current source 412 is configured using a sink drive IC, for example. As shown in this figure, the illustrated current source 412 includes a communication processing unit 451, an input / output processing unit 452, and a current generation unit 453.

[0122] The communication processing unit 451 functions as a CAN transceiver, for example. The communication processing unit 451 performs communication with the rear ECU 23, such as receiving information (lighting state indication, etc.) sent from the rear ECU 23. The information received by the communication processing unit 451 from the rear ECU 23 is notified to the current generation unit 453, for example.

[0123] The input / output processing unit 452 includes an analog input processing unit 4521 and a digital input processing unit 4522. The analog input processing unit 4521 receives an analog value input from the outside and notifies the received analog value to the current generation unit 453. The digital input processing unit 4522 receives a digital value input from the outside and notifies the received digital value to the current generation unit 453.

[0124] The current generation unit 453 controls the value of the current output from the constant current source 4121 based on the information (lighting state indication, etc.) notified by the communication processing unit 451 and the information notified by the input / output processing unit 452.

[0125] As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments and includes various modifications. In addition, the above-described embodiments have described the structure in detail for easy understanding of the present invention, and it is not necessary to be limited to having all the structures described. In addition, for a part of the structure of the above-described embodiments, addition, deletion, or replacement can be made in other structures.

[0126] For example, in the above content, one LED column 400 provided on the LED substrate 42 has been described. However, in the case where a plurality of LED columns 400 are provided on the LED substrate 42, the above-described structure can be applied to each LED column 400.

[0127] As described above, the vehicle lamp control device 1 of the present embodiment includes: a first constant current source that supplies a constant current to a light-emitting element used in a vehicle lamp; a resistance circuit that is connected in series with the light-emitting element and the first constant current source; a current value control circuit that controls the value of the current of the first constant current source according to a lighting state indication indicating the lighting state of the light-emitting element; and a resistance value control circuit that changes the value of the resistance of the resistance circuit to suppress a change in the value of the voltage applied to the first constant current source when the value of the current supplied to the light-emitting element changes.

[0128] According to the above structure, it is possible to change the value of the resistance of the resistance circuit to suppress a change in the value of the voltage applied to the first constant current source when the value of the current supplied to the light-emitting element changes. For example, even when the lighting control of the light-emitting element of the vehicle lamp is performed in various ways such as by animation, the value of the voltage applied to the first constant current source can be maintained within a specified range. Therefore, it is possible to prevent an increase in power consumption, heat generation, and non-lighting of the light-emitting element due to the value of the voltage applied to the first constant current source being too large or too small.

[0129] In addition, the vehicle lamp control device 1 of the present embodiment further includes a second constant current source that supplies a current corresponding to the lighting state indication, and the resistance value control circuit changes the value of the resistance of the resistance circuit according to the value of the current supplied by the second constant current source.

[0130] In this way, the vehicle lamp control device 1 changes the value of the resistance of the resistance circuit by using the constant current source (second constant current source) provided in the current source having a plurality of constant current sources. Therefore, it is possible to realize a structure for controlling the value of the resistance of the resistance circuit according to the lighting state indication with a simple structure.

[0131] In addition, the above-mentioned resistance circuit of the vehicle lamp control device 1 of the present embodiment includes: a first resistance element connected in series with the light-emitting element; and a second resistance element and a switch connected in series with the light-emitting element and connected in parallel with the first resistance element. The resistance value control circuit turns the switch on and off according to the current value of the second constant current source.

[0132] According to the above structure, a structure for controlling the resistance value of the resistance circuit according to the lighting state indication can be realized with a simple structure.

[0133] In addition, the above-mentioned resistance circuit of the vehicle lamp control device 1 of the present embodiment includes: a first resistance element connected in series with the light-emitting element; and a diode and a switch connected in series and forward-connected with the light-emitting element and connected in parallel with the first resistance element. The resistance value control circuit turns the switch on and off according to the current value of the second constant current source.

[0134] According to the above structure, a structure for controlling the resistance value of the resistance circuit according to the change in the temperature of the light-emitting element can be realized with a simple structure. In addition, the resistance value of the resistance circuit can be made zero by energizing the diode.

[0135] In addition, the above-mentioned resistance circuit of the vehicle lamp control device 1 of the present embodiment includes a variable resistance element whose resistance value changes according to a control voltage, and the above-mentioned resistance value control circuit outputs a control voltage corresponding to the current value of the second constant current source.

[0136] In this way, by using the variable resistance element, a structure for changing the resistance value of the resistance circuit according to the lighting state indication can be realized with a simple structure.

[0137] In addition, the first constant current source and the second constant current source of the vehicle lamp control device 1 of the present embodiment are different constant current sources of an integrated circuit having a plurality of constant current sources.

[0138] Therefore, by using an integrated circuit having a plurality of constant current sources such as a driving IC, a structure for changing the resistance value of the resistance circuit according to the lighting state indication can be realized with a simple structure.

[0139] In addition, the vehicle lamp control device 1 of the present embodiment further includes a receiving circuit that receives a lighting state indication from another device communicably connected, and the resistance value control circuit changes the resistance value of the resistance circuit according to the lighting state indication received by the receiving circuit.

[0140] In this way, according to the above structure, since another device such as a rear ECU directly controls the resistance value of the resistance circuit, a structure for changing the resistance value of the resistance circuit according to the lighting state indication can be realized without consuming the resources (constant current sources) of the current source (driving IC).

[0141] In addition, the above-mentioned resistance circuit of the vehicle lighting control device 1 of the present embodiment includes: a first resistance element, which is connected in series with the light-emitting element; and a second resistance element and a switch, which are connected in series with the light-emitting element and connected in parallel with the first resistance element, and the resistance value control circuit is configured to turn the switch on and off according to the lighting status indication.

[0142] According to the above configuration, a configuration for controlling the resistance value of the resistance circuit according to the lighting state instruction can be realized with a simple configuration.

[0143] In addition, the vehicle lighting control device 1 of the present embodiment includes a second information processing device, which is communicatively connected to the first information processing device, and the second information processing device stores software for implementing a process for generating a lighting status indication, receives software update information from the first information processing device, and based on the received update information, updates the software to content that causes the value of the current supplied to the light-emitting element to change before and after the update.

[0144] The change in the value of the current supplied to the light emitting element also occurs when the software for implementing the process of generating the lighting state indication stored in the second information processing device is updated based on the information received from the first information processing device. According to the above structure, even in such a case, the value of the voltage applied to the first constant current source can be maintained within a specified range.

[0145] [Second embodiment]

[0146] exist Figure 3 In the structure shown, when the temperature of LED405 changes and the value of the voltage applied to the constant current source (hereinafter referred to as "Vk") changes, there is a possibility that the power consumption and heat generation will increase due to the excessive value of the voltage (Vk) applied to the constant current source, or the LED405 may not light up due to the excessive value of the voltage (Vk) applied to the constant current source.

[0147] In addition, when the ambient temperature changes, for example, the lighting method of LED 405 is changed according to the lighting state instruction from the rear ECU 23, and the value of the current supplied to LED 405 changes, the temperature of LED 405 changes. Figure 8A as well as Figure 8B Next, as an example, a case where the temperature of the LED 405 rises (a case where the temperature of the LED 405 rises from a low temperature (Tb) to a high temperature (Ta (>Tb))) is considered.

[0148] Here, for example,Figure 8A As shown, consider the case where the resistance value of the resistance element 422 of the LED substrate 42 is designed based on the low temperature (Tb), that is, the case where the value of the voltage (Vk) of the constant current source 4121 is appropriate when the temperature of the LED 405 is the low temperature (Tb). In this case, as Figure 8A shown in (a) of, when the temperature of the LED 405 is the low temperature (Tb), the voltage drop of the LED 405 is appropriate, and the value of the voltage (Vk) applied to the constant current source 4121 is also appropriate. On the other hand, as Figure 8A shown in (b) of, if the temperature of the LED 405 rises to the high temperature (Ta), the voltage drop of the LED 405 decreases. As a result, the value of the voltage (Vk) applied to the constant current source 4121 rises (excessively), leading to an increase in power consumption and heat generation.

[0149] In addition, for example, as Figure 8B shown, consider the case where the resistance value of the resistance element 422 of the LED substrate 42 is designed based on the high temperature (Ta), that is, the case where the value of the voltage (Vk) of the constant current source 4121 is appropriate when the temperature of the LED 405 is the high temperature (Ta). In this case, as Figure 8B shown in (a) of, when the temperature of the LED 405 is the high temperature (Ta), the voltage drop of the LED 405 is appropriate, and the value of the voltage (Vk) applied to the constant current source 4121 is also appropriate. On the other hand, as Figure 8B shown in (b) of, if the temperature of the LED 405 drops to the low temperature (Tb), the voltage drop of the LED 405 increases. As a result, the value of the voltage (Vk) applied to the constant current source 4121 decreases. Moreover, when the value of the voltage (Vk) is lower than the lower limit value of the voltage required for the normal operation of the constant current source 4121 (in the case of being too small), the LED 405 does not light up.

[0150] In this way, when the value of the resistance element 422 is fixed, due to the temperature change of the LED 405, it is possible to cause an increase in the power consumption and heat generation of the constant current source 4121 and the non - lighting of the LED 405.

[0151] Therefore, in the present embodiment, by providing a resistance circuit (hereinafter referred to as "resistance circuit 420") capable of changing the resistance value in the LED column 400, such a technical problem is solved. Next, some structures of the vehicle lamp control device 1 of the present embodiment will be specifically described.

[0152] Figure 9AThis is a structural example of the vehicle lamp control device 1 according to the present embodiment. In the illustrated vehicle lamp control device 1, a resistor circuit 420 is provided in series with the LED 405 that constitutes the LED array 400, and a circuit for controlling the resistance value of the resistor circuit 420 (hereinafter referred to as "resistance value control circuit 440") is provided. The resistor circuit 420 includes: a resistor element 422a; a resistor element 422b that is connected in parallel with the resistor element 422a; and a switch 423 that is connected in series with the resistor element 422b and conducts or disconnects the connection with the LED 405. The specific structure of the resistance value control circuit 440 will be described later.

[0153] A temperature sensor 45 is provided at a specified position on the LED substrate 42. The temperature sensor 45 acquires information indicating the temperature around the LED 405 (hereinafter referred to as "temperature information"). The temperature information acquired (measured) by the temperature sensor 45 is notified (input) to the current source 412 of the rear lamp lighting control circuit 41 via a circuit such as a wiring or a communication line. In addition, the temperature information does not necessarily have to be the temperature of the element of the LED 405 itself, as long as it is information such as the temperature around the LED 405 that can indirectly determine or estimate the temperature of the LED 405. For example, the temperature information can also be acquired by other types of sensors based on other principles, such as an optical sensor, a total radiation thermometer, an optical pyrometer, or an infrared thermometer.

[0154] In the example of this figure, the on / off control of the switch 423 is performed by changing the current value of another constant current source 4121 among the multiple constant current sources 4121 provided in the current source 412, which is different from the constant current source 4121 (hereinafter also referred to as "first constant current source 4121a") that supplies current to the LED array 400 (hereinafter also referred to as "second constant current source 4121b").

[0155] The current source 412 controls the current value of the second constant current source 4121b based on the notified temperature information, thereby controlling the on / off of the switch 423 and switching the resistance value of the resistor circuit 420.

[0156] For example, when the temperature of the LED 405 is high, the current source 412 changes the current value of the second constant current source 4121b, thereby disconnecting the switch 423 and increasing the resistance value of the resistor circuit 420 (increasing the voltage drop across the resistor circuit 420) to prevent the voltage applied to the first constant current source 4121a from rising.

[0157] In addition, for example, when the temperature of the LED 405 is low, the current source 412 changes the current value of the second constant current source 4121b, thereby turning on the switch 423 and reducing the resistance value of the resistor circuit 420 (reducing the voltage drop across the resistor circuit 420) to prevent the voltage applied to the first constant current source 4121a from decreasing.

[0158] In addition, the boundary values (threshold values) used to determine the high or low temperature of the LED 405 are set according to, for example, the characteristics of the LED 405 and the characteristics of the current source 412 (constant current source 4121).

[0159] In this way, in the illustrated vehicle lamp control device 1, the resistance value of the resistance circuit 420 is changed to suppress the change in the voltage value applied to the first constant current source 4121a due to the change in the temperature of the LED 405. Therefore, even when the temperature of the LED 405 changes, the voltage value applied to the first constant current source 4121a can be maintained within a specified range. Therefore, it is possible to prevent an increase in power consumption and heat generation due to an excessive voltage value (Vk) applied to the first constant current source 4121a. In addition, it is possible to prevent the LED 405 from not lighting up due to the voltage value (Vk) applied to the first constant current source 4121a being lower than the value required for the normal operation of the first constant current source 4121a (being too small).

[0160] In addition, in the illustrated vehicle lamp control device 1, the current source 412 changes the current value of the second constant current source 4121b different from the first constant current source 4121a among the plurality of constant current sources 4121 included in the current source 412, that is, uses the second constant current source 4121b, one of the constant current sources 4121 of the current source 412, to change the resistance value of the resistance circuit 420. Therefore, it is possible to realize a structure for controlling the resistance value of the resistance circuit 420 according to the lighting state indication with a simple structure.

[0161] Figure 9B is the case of forming using a transistor Figure 9A for the switch 423 shown. In this example, the emitter of the transistor is connected to the voltage source 411, and the collector is connected to the resistance element 422b. In addition, the base of the transistor is connected to the second constant current source 4121b via the resistance element 422c and is also connected to the voltage source 411 via the resistance element 422d. A voltage determined by the following values is applied to the base of the transistor: the voltage value of the voltage source 411, the current value supplied from the second constant current source 4121b, the resistance value of the resistance element 422c, and the resistance value of the resistance element 422d. That is, in the example of this figure, the resistance value control circuit 440 is composed of the resistance element 422c and the resistance element 422d.

[0162] In addition, in Figure 9B the example, the switch 423 is formed using a PNP-type transistor. Therefore, when the current value supplied from the second constant current source 4121b is small and the voltage drop at the resistance element 422d is below a specified value, the switch 423 is turned off, and when the above current value is large and the voltage drop at the resistance element 422d exceeds the specified value, the switch 423 is turned on.

[0163] In addition, the switch 423 can also be constituted by other types of elements such as a field-effect transistor (FET: Field-Effect Transistor), for example. When the switch 423 is constituted by a field-effect transistor, the drain is connected to the voltage source 411, and the source is connected to the resistance element 422b. Further, for the gate, it is connected to the second constant current source 4121b via the resistance element 422c, and is connected to the voltage source 411 via the resistance element 422d.

[0164] In this way, the on / off of the switch 423 can be controlled by changing the value of the current supplied from the second constant current source 4121b. In addition, a structure for controlling the resistance value of the resistance circuit 420 based on temperature information can be simply constituted using the resistance element and the switch 423.

[0165] Figure 9C This is another structural example of the vehicle lamp control device 1. In this example, a diode 424 connected in the forward direction to the LED column 400 is used to replace Figure 9B the resistance element 422b connected in series with the switch 423 of the resistance circuit 420. The resistance value of the resistance circuit 420 when the switch 423 is off becomes the resistance value of the resistance element 422a. In addition, when the switch 423 is on, the resistance value of this resistance circuit 420 becomes zero. Further, in order to make the resistance value of the resistance circuit 420 a specified value other than zero even when the switch 423 is on, for example, a resistance element may be connected in series with the switch 423. Although the specific structure is omitted in this figure, as the resistance value control circuit 440 in this resistance circuit 420, for example, the circuit shown in Figure 9B (a circuit constituted by the resistance element 422c and the resistance element 422d) can be used.

[0166] Figure 9D This is another structural example of the vehicle lamp control device 1. In this example, the resistance value of the resistance circuit 420 connected to the LED column 400 is changed by a variable resistance element 522a connected in series with the LED column 400. In this example, as the variable resistance element 522a, a potentiometer (hereinafter referred to as an "analog potentiometer") of a type that sets the resistance value by an analog value (voltage value) is used.

[0167] As shown in the figure, the input terminal 5221 of the analog value of the variable resistor element 522a is connected to the second constant current source 4121b. A voltage obtained by dividing the voltage of the voltage source 411 by the resistance value of the resistor element 522b and the resistance value of the resistor element 522c is applied to the input terminal 5221. The resistance values of the resistor element 522b and the resistor element 522c are set, for example, according to the range of the resistance value required by the resistor circuit 420. In the case of this circuit, the resistance value control circuit 440 is composed of the resistor element 522b and the resistor element 522c.

[0168] And Figure 9D Similarly, Figure 9E The vehicle lamp control device 1 shown is a case where the resistance value of the resistor circuit 420 connected to the LED column 400 is changed by the variable resistor element 522a connected in series with the LED column 400. In this example, as the variable resistor element 522a, a potentiometer (hereinafter referred to as "digital potentiometer") that sets the resistance value by using a digital value specifying the resistance value is used.

[0169] In this example, the analog voltage value divided by the resistor element 522b and the resistor element 522c is converted into a digital value by the A / D conversion circuit 525, and the converted digital value is input to the digital value input terminal 5222 of the variable resistor element 522a. In the case of this circuit, the resistance value control circuit 440 is composed of the resistor element 522b, the resistor element 522c, and the A / D conversion circuit 525.

[0170] In this way, the structure that changes the resistance value of the resistor circuit 420 according to the short - circuit information can be simply composed of variable resistor elements such as an analog potentiometer and a digital potentiometer. In addition, when using a digital potentiometer as the variable resistor element 522a, the advantages of the digital potentiometer (high precision, high resolution, small size, high stability, long life, high reliability, etc.) can be enjoyed.

[0171] In addition, in the structure shown above, Figures 9A - 9C since the resistance values of the resistor element 422a and the resistor element 422b are fixed, the resistance value of the resistor circuit 420 can only be switched periodically (discontinuously). In contrast, in Figure 9D or Figure 9E the structure shown, since a variable resistor element is used, the resistance value of the resistor circuit 420 can be changed continuously. Therefore, the value of the resistor circuit 420 can be finely controlled according to the temperature information.

[0172] Figures 10A - 10D is another structural example of the vehicle lamp control device 1. In Figures 9A - 9EIn the vehicle lamp control device 1 shown, the value of the resistance of the resistance circuit 420 is changed by the constant current source 4121 (second constant current source 4121b) of the current source 412. In contrast, in Figures 10A - 10D In the vehicle lamp control device 1 shown, the short-circuit information acquisition unit 4125 of the rear lamp lighting control circuit 41 notifies the rear ECU 23 of the temperature information acquired by the temperature sensor 45, and the rear ECU 23 sends a switching instruction (hereinafter referred to as "resistance value instruction") of the value of the resistance of the resistance circuit 420 to the LED substrate 42 based on the notified temperature information. The LED substrate 42 switches the value of the resistance of the resistance circuit 420 based on the resistance value instruction received from the rear ECU 23.

[0173] Figure 10A The resistance circuit 420 in the vehicle lamp control device 1 shown is, for example, the same as Figure 9A or Figure 9B shown. As shown in this figure, the temperature information acquired (measured) by the temperature sensor 45 is notified to the rear ECU 23 via a circuit such as a wiring or a communication line. In this example, on the LED substrate 42, a communication circuit 431 (such as a CAN transceiver) for receiving a lighting state instruction, a decoder circuit 432 for decoding the received lighting state instruction, a D / A conversion circuit 433 for converting the decoded digital value into an analog value, and a conduction-disconnection control circuit 434 for controlling the conduction and disconnection of the switch 423 based on the converted analog value are provided.

[0174] In addition, in the lighting state instruction received by the communication circuit 431, for example, a parameter indicating conduction or disconnection of the switch 423 is included. The D / A conversion circuit 433 generates an analog value corresponding to the value of the above parameter and inputs it to the conduction-disconnection control circuit 434. In the case of this example, the resistance value control circuit 440 is composed of the communication circuit 431, the decoder circuit 432, the D / A conversion circuit 433, and the conduction-disconnection control circuit 434.

[0175] In this way, a structure for controlling the value of the resistance of the resistance circuit 420 according to the temperature information can also be realized by the structure shown in this figure. In addition, in the case of such a structure, the above structure can be realized without consuming the resources (constant current source) of the current source 412.

[0176] In Figure 10B In the vehicle lamp control device 1 shown, similarly to the case of the vehicle lamp control device 1 shown in Figure 9C replace with a forward-connected diode 424 Figure 10AThe resistance element 422b of the resistance circuit 420. In this example, the resistance value of the resistance circuit 420 when the switch 423 is turned on can be made zero. Further, for example, by connecting in series a resistance element 422b having a resistance value greater than zero with the switch 423, the resistance value of the resistance circuit 420 when the switch 423 is turned on can be made a specified value greater than zero.

[0177] In Figure 10C and Figure 10D with Figure 9D and Figure 9E shown in the vehicle lamp control device 1, the resistance circuit 420 is similarly constituted by using a variable resistance element 522a.

[0178] Figure 10C is a case where Figure 9D similarly uses an analog potentiometer as the variable resistance element 522a. In this example, on the LED substrate 42, there are provided: a communication circuit 431 (such as a CAN transceiver) that receives a resistance value indication; a decoder circuit 432 that decodes the resistance value indication; and a D / A conversion circuit 433 that converts the decoded digital value into an analog value and inputs it to the analog value input terminal 5221 of the variable resistance element 522a. In the case of this circuit, the resistance value control circuit 440 is constituted by the communication circuit 431, the decoder circuit 432, and the D / A conversion circuit 433.

[0179] Figure 10D is a case where Figure 9E similarly uses a digital potentiometer as the variable resistance element 522a. In this example, on the LED substrate 42, there are provided: a communication circuit 431 (such as a CAN transceiver) that receives a resistance value indication; and a decoder circuit 432 that decodes the resistance value indication and inputs the decoded digital value to the digital value input terminal 5222 of the variable resistance element 522a. In the case of this circuit, the resistance value control circuit 440 is constituted by the communication circuit 431 and the decoder circuit 432.

[0180] As described above, the vehicle lamp control device 1 of the present embodiment varies the resistance value of the resistance circuit 420 to suppress the change in the voltage value (Vk) applied to the first constant current source 4121a due to the change in the temperature of the LED 405. Therefore, even when the temperature of the LED 405 changes, the voltage value applied to the first constant current source 4121a can be maintained within a specified range. Accordingly, it is possible to prevent an increase in power consumption and heat generation due to the voltage value (Vk) applied to the first constant current source 4121a being too large, and the non - lighting of the LED 405 due to the voltage value (Vk) applied to the first constant current source 4121a being lower than the value required for the normal operation of the first constant current source 4121a (being too small).

[0181] Figure 11 It is a block diagram showing a structural example of the current source 412. The illustrated current source 412 is configured using, for example, a sink drive IC. As shown in this figure, the illustrated current source 412 includes a communication processing unit 451, an input / output processing unit 452, and a current generation unit 453.

[0182] The communication processing unit 451 functions as, for example, a CAN transceiver. The communication processing unit 451 performs communication with the rear ECU 23, such as receiving information (resistance value indication, etc.) sent from the rear ECU 23. The information received by the communication processing unit 451 from the rear ECU 23 is, for example, notified to the current generation unit 453.

[0183] The input / output processing unit 452 includes an analog input processing unit 4521 and a digital input processing unit 4522. The analog input processing unit 4521 receives an analog value input from the outside (for example, if the temperature sensor 45 of the LED substrate 42 is of a type that outputs an analog value (analog voltage value) representing temperature, it is the analog value input from the temperature sensor 45), and notifies the received analog value to the current generation unit 453. The digital input processing unit 4522 receives a digital value input from the outside, and notifies the received digital value to the current generation unit 453 (for example, if the temperature sensor 45 of the LED substrate 42 is of a type that outputs a digital value representing temperature, it is the digital value input from the temperature sensor 45).

[0184] The current generation unit 453 controls the value of the current output from the constant current source 4121 based on the information (temperature information, etc.) notified by the input / output processing unit 452 and the information (resistance value indication, etc.) notified by the communication processing unit 451.

[0185] As described above, the embodiments of the present invention have been described in detail, but the present invention is not limited to the above embodiments and includes various modification examples. In addition, the above embodiments have described the structure in detail for easy understanding of the present invention, and it is not necessary to be limited to having all the described structures. In addition, for a part of the structure of the above embodiments, addition, deletion, and replacement can be made in other structures.

[0186] For example, in the above content, one LED column 400 has been described, but in the case where a plurality of LED columns 400 are provided on the LED substrate 42, the above-described structure can be applied to each LED column 400.

[0187] As described above, the vehicle lamp control device 1 according to the present embodiment includes: a first constant current source that supplies a constant current to a light-emitting element used in a vehicle lamp; a resistance circuit that is connected in series with the light-emitting element and the first constant current source; a current value control circuit that controls the value of the current of the first constant current source; and a resistance value control circuit that changes the resistance value of the resistance circuit to suppress a change in the value of the voltage applied to the first constant current source when the temperature around the light-emitting element changes.

[0188] In this way, the vehicle lamp control device 1 changes the resistance value of the resistance circuit to suppress a change in the value of the voltage applied to the first constant current source when the temperature of the light-emitting element changes. Therefore, even when the temperature of the light-emitting element changes, the value of the voltage applied to the first constant current source can be maintained within a specified range. Therefore, it is possible to prevent an increase in power consumption, heat generation, and non-illumination of the light-emitting element due to the value of the voltage applied to the first constant current source being too large or too small.

[0189] In addition, the vehicle lamp control device 1 according to the present embodiment further includes a second constant current source that supplies a current corresponding to the temperature around the light-emitting element, and the resistance value control circuit changes the resistance value of the resistance circuit according to the value of the current supplied by the second constant current source.

[0190] In this way, the vehicle lamp control device 1 changes the resistance value of the resistance circuit by using the constant current source (second constant current source) provided in the current source having a plurality of constant current sources. Therefore, a structure for controlling the resistance value of the resistance circuit according to the temperature around the light-emitting element can be realized with a simple structure.

[0191] In addition, the above resistance circuit of the vehicle lamp control device 1 according to the present embodiment includes: a first resistance element that is connected in series with the light-emitting element; and a second resistance element and a switch that are connected in series with the light-emitting element and are connected in parallel with the first resistance element, and the resistance value control circuit turns the switch on and off according to the value of the current of the second constant current source.

[0192] According to the above structure, a structure for controlling the resistance value of the resistance circuit according to the temperature around the light-emitting element can be realized with a simple structure.

[0193] In addition, the above resistance circuit of the vehicle lamp control device 1 according to the present embodiment includes: a first resistance element that is connected in series with the light-emitting element; and a diode and a switch that are connected in series with the light-emitting element in the forward direction and are connected in parallel with the first resistance element, and the resistance value control circuit turns the switch on and off according to the value of the current of the second constant current source.

[0194] According to the above structure, a structure can be realized by a simple structure to control the resistance value of the resistance circuit according to the temperature around the light-emitting element. In addition, the resistance value of the resistance circuit can be made zero by energizing the diode.

[0195] In addition, the above resistance circuit of the vehicle lamp control device 1 according to the present embodiment includes a variable resistance element whose resistance value changes according to a control voltage, and the resistance value control circuit outputs a control voltage corresponding to the current value of the second constant current source.

[0196] In this way, by using the variable resistance element, a structure can be realized by a simple structure to control the resistance value of the resistance circuit according to the temperature around the light-emitting element.

[0197] In addition, the first constant current source and the second constant current source of the vehicle lamp control device 1 according to the present embodiment are different constant current sources of an integrated circuit having a plurality of constant current sources.

[0198] Therefore, an integrated circuit having a plurality of constant current sources such as a driving IC can be used, and a structure can be realized by a simple structure to control the resistance value of the resistance circuit according to the temperature around the light-emitting element.

[0199] In addition, the vehicle lamp control device 1 according to the present embodiment further includes: a temperature information acquisition circuit that acquires temperature information indicating the temperature around the light-emitting element; a notification circuit that notifies the temperature information to other devices communicably connected; and a reception circuit that receives a resistance value instruction notified by other devices based on the temperature information, where the resistance value instruction is used to indicate the resistance value of the resistance circuit, and the resistance value control circuit changes the resistance value of the resistance circuit according to the resistance value instruction received by the reception circuit.

[0200] In this way, according to the above structure, other devices such as a rear ECU directly control the resistance value of the resistance circuit, so a structure can be realized to change the resistance value of the resistance circuit according to the lighting state instruction without consuming the resources (constant current sources) of the current source (driving IC).

[0201] In addition, the above resistance circuit of the vehicle lamp control device 1 according to the present embodiment includes: a first resistance element connected in series with the light-emitting element; and a second resistance element and a switch connected in series with the light-emitting element and connected in parallel with the first resistance element, and the resistance value control circuit conducts and disconnects the switch according to the resistance value instruction.

[0202] According to the above structure, a structure can be realized by a simple structure to control the resistance value of the resistance circuit according to the resistance value instruction.

[0203] [Third Embodiment]

[0204] InFigure 3 In the structure shown, for example, if one of the LEDs 405 that make up the LED column 400 is short-circuited, the voltage drop across the LED column 400 decreases, and the value of the voltage applied to the constant current source 4121 that supplies current to the LED column 400 (hereinafter referred to as "Vk") increases, which may cause an increase in the power consumption and heat generation of the constant current source 4121. Next, with reference to Figure 12 This situation will be specifically described.

[0205] For example, consider the case where the value of the resistance element 422 is designed as follows: The LED column 400 includes two LEDs 405a and 405b connected in series, and when they are normally lit, the value of the voltage (Vk) of the constant current source 4121 is appropriate.

[0206] In this case, as Figure 12 shown in (a) of, when both the LED 405a and the LED 405b are operating normally, the voltage drops across the LED 405a and the LED 405b are appropriate, and the value of the voltage (Vk) applied to the constant current source 4121 is also appropriate.

[0207] On the other hand, as Figure 12 shown in (b) of, if one of the LEDs 405 (for example, "LED 405a") is short-circuited, the voltage drops across the LED 405a and the LED 405b decrease, and the value of the voltage (Vk) applied to the constant current source 4121 changes, resulting in an increase in the power consumption and heat generation of the constant current source 4121.

[0208] In this way, in Figure 3 the structure of the vehicle lamp control device 1 shown, if the resistance value of the resistance element 422 is fixed, when the LED 405 is short-circuited, it may cause an increase in the power consumption and heat generation of the constant current source 4121.

[0209] Therefore, in the present embodiment, by providing a resistance circuit capable of changing the resistance value in the LED column 200, the above technical problem is solved. Next, the specific structure of the vehicle lamp control device 1 of the present embodiment will be described.

[0210] Figure 13AThis is a structural example of the vehicle lamp control device 1 according to the present embodiment. In the illustrated vehicle lamp control device 1, a resistance circuit 420 is provided in series with the LEDs 405 constituting the LED array 400, and a circuit for controlling the resistance value of the resistance circuit 420 (hereinafter referred to as "resistance value control circuit 440") is provided. The resistance circuit 420 includes: a resistance element 422a; a resistance element 422b connected in parallel with the resistance element 422a; and a switch 423 connected in series with the resistance element 422b and configured to conduct or disconnect the connection to the LED 405. The specific structure of the resistance value control circuit 440 will be described later.

[0211] In the example of this figure, the conduction and disconnection of the switch 423 are controlled by changing the current value of another constant current source 4121 (hereinafter also referred to as "second constant current source 4121b") different from the constant current source 4121 (hereinafter also referred to as "first constant current source 4121a") that supplies current to the LED array 400 among the plurality of constant current sources 4121 provided in the current source 412.

[0212] The current source 412 has a short-circuit information acquisition unit 4125 for acquiring information indicating whether a short circuit has occurred in the LEDs 405 constituting the LED array 400 (hereinafter referred to as "short-circuit information"). The short-circuit information acquisition unit 4125 can be, for example, a short-circuit detection circuit provided in the driving IC constituting the current source 412, or a circuit separately provided in the rear lamp lighting control circuit 41.

[0213] In addition, the short-circuit information acquisition unit 4125 determines whether a short circuit has occurred in the LEDs 405 of the LED array 400 by monitoring, for example, the voltage value (Vk) of the first constant current source 4121a of the current source 412. For example, the short-circuit information acquisition unit 4125 detects whether a short circuit has occurred in the LEDs 405 of the LED array 400 connected to the first constant current source 4121a based on whether the voltage value (Vk) of the first constant current source 4121a is higher than a specified voltage. Here, the above-mentioned specified voltage is set based on, for example, the voltage value applied to the LED array 400 by the voltage source 411, the resistance value of the resistance circuit 420, the voltage drop of the LEDs 405, and the constant current value of the first constant current source 4121a.

[0214] The current source 412 controls the current value of the second constant current source 4121b according to the short-circuit information acquired by the short-circuit information acquisition unit 4125, and switches the conduction and disconnection of the switch 423.

[0215] For example, when the current source 412 detects that none of the LEDs 405 constituting the LED column 400 is short-circuited based on the short-circuit information, it maintains the current value of the second constant current source 4121b at a specified value, turns on the switch 423, and reduces the resistance value of the resistor circuit 420 (reduces the voltage drop across the resistor circuit 420) to maintain the voltage value (Vk) applied to the first constant current source 4121a in an appropriate manner.

[0216] Further, for example, when the current source 412 detects that one of the LEDs 405 constituting the LED column 400 is short-circuited through the short-circuit information, it controls the current value of the second constant current source 4121b, turns off the switch 423, and increases the resistance value of the resistor circuit 420 (increases the voltage drop across the resistor circuit 420) to prevent the voltage value (Vk) applied to the first constant current source 4121a from rising.

[0217] In addition, it is also assumed that when there are three or more LEDs 405 constituting the same LED column 400, two or more of the LEDs 405 are short-circuited simultaneously. In this case, the short-circuit information acquisition unit 4125 can also acquire information indicating whether at least any one of the multiple LEDs 405 is short-circuited as the short-circuit information, and control the resistance value of the resistor circuit 420 based on the magnitude of the voltage drop grasped from the acquired short-circuit information. By doing so, even when two or more of the LEDs 405 constituting the LED column 400 are short-circuited simultaneously, the change in the voltage value (Vk) applied to the first constant current source 4121a can be appropriately suppressed. Further, when it is detected that all the LEDs 405 constituting the LED column 400 are short-circuited, the current source 412, for example, stops supplying current from the first constant current source 4121a to the LED column 400, or treats the LED column 400 as a small resistance load, and controls the resistance value of the resistor circuit 420 in the same manner as when a part of the LEDs 405 are short-circuited, suppressing the change in the voltage value (Vk) applied to the first constant current source 4121a.

[0218] In this way, the illustrated vehicle lamp control device 1 controls the resistance value of the resistor circuit 420 by controlling the current value supplied from the second constant current source based on the short-circuit information, thereby suppressing the change in the voltage value (Vk) applied to the first constant current source 4121a. Therefore, even when the LEDs 405 constituting the LED column 400 are short-circuited, the voltage value (Vk) applied to the first constant current source 4121a can be maintained at an appropriate value.

[0219] In the illustrated vehicle lamp control device 1, the current source 412 changes the value of the current of the second constant current source 4121b different from the first constant current source 4121a among the plurality of constant current sources 4121 included in the current source 412, that is, the second constant current source 4121b, which is one of the constant current sources 4121 of the current source 412, changes the value of the resistance of the resistance circuit 420. Therefore, a structure for controlling the value of the resistance of the resistance circuit 420 according to the short-circuit information can be realized with a simple structure.

[0220] Figure 13B It is composed of transistors Figure 13A 4. The switch 423 shown in FIG. 4 is a case where the emitter of the transistor is connected to the voltage source 411, and the collector is connected to the resistor 422b. In addition, the base of the transistor is connected to the second constant current source 4121b via the resistor 422c, and is connected to the voltage source 411 via the resistor 422d. A voltage determined by the following values is applied to the base of the transistor: the value of the voltage of the voltage source 411, the value of the current supplied from the second constant current source 4121b, the value of the resistance of the resistor 422c, and the value of the resistance of the resistor 422d. That is, in the example of the figure, the resistance value control circuit 440 is composed of the resistor 422c and the resistor 422d.

[0221] In addition, Figure 13B In the example, a PNP type transistor is used to constitute the switch 423. Therefore, when the value of the current supplied from the second constant current source 4121b is small and the voltage drop at the resistor 422d is less than a specified value, the switch 423 is turned off, and when the value of the current is large and the voltage drop at the resistor 422d exceeds a specified value, the switch 423 is turned on.

[0222] In addition, the switch 423 may also be formed using other types of elements such as a field effect transistor (FET). When the switch 423 is formed using a field effect transistor, the drain is connected to the voltage source 411, and the source is connected to the resistor 422b. In addition, the gate is connected to the second constant current source 4121b via the resistor 422c, and is connected to the voltage source 411 via the resistor 422d.

[0223] Thus, the on and off of the switch 423 can be controlled by changing the value of the current supplied from the second constant current source 4121b. In addition, the structure for controlling the resistance value of the resistance circuit according to the short-circuit information can be simply configured using a resistance element and the switch 423.

[0224] Figure 13C FIG. 4 is another configuration example of the vehicle lamp control device 1. In this example, the diode 424 connected in the forward direction to the LED array 400 is used instead ofFigure 13B A resistor element 422b that is serially connected to a switch 423 of a resistor circuit 420. When the switch 423 is off, the resistance value of the resistor circuit 420 becomes the resistance value of the resistor element 422a. Further, when the switch 423 is on, the resistance value of this resistor circuit 420 becomes zero. In addition, in order to make the resistance value of the resistor circuit 420 a specified value other than zero even when the switch 423 is on, for example, a resistor element may be connected in series with the switch 423. Although the specific structure is omitted in this figure, as the resistance value control circuit 440 in this resistor circuit 420, for example, the Figure 13B circuit shown (a circuit composed of a resistor element 422c and a resistor element 422d) can be used.

[0225] Figure 13D is another structural example of the vehicle lamp control device 1. In this example, the resistance value of the resistor circuit 420 connected to the LED column 400 is changed by a variable resistor element 522a serially connected to the LED column 400. In this example, as the variable resistor element 522a, a potentiometer of a type that sets the resistance value by inputting an analog value (voltage value) (hereinafter referred to as an "analog potentiometer") is used.

[0226] As shown in this figure, an analog value input terminal 5221 of the variable resistor element 522a is connected to a second constant current source 4121b. A voltage obtained by dividing the voltage of the voltage source 411 by the resistance value of the resistor element 522b and the resistance value of the resistor element 522c is applied to the input terminal 5221. The resistance value of the resistor element 522b and the resistance value of the resistor element 522c are set, for example, according to the range of the resistance value required for the resistor circuit 420. In this example, the resistance value control circuit 440 is composed of the resistor element 522b and the resistor element 522c.

[0227] Similar to Figure 13D the above, Figure 13E the vehicle lamp control device 1 shown is a case where the resistance value of the resistor circuit 420 connected to the LED column 400 is changed by a variable resistor element 522a serially connected to the LED column 400. In this example, as the variable resistor element 522a, a potentiometer of a type that sets the resistance value by inputting a digital value for specifying the resistance value (hereinafter referred to as a "digital potentiometer") is used.

[0228] In this example, the value of the analog voltage divided by the resistance element 522b and the resistance element 522c is converted into a digital value by the A / D conversion circuit 525, and the converted digital value is input to the input terminal 5222 of the digital value of the variable resistance element 522a. In the case of this circuit, the resistance value control circuit 440 is composed of the resistance element 522b, the resistance element 522c, and the A / D conversion circuit 525.

[0229] In this way, the structure that changes the resistance value of the resistance circuit 420 according to the short-circuit information can be simply constituted by using variable resistance elements such as an analog potentiometer and a digital potentiometer. In addition, when a digital potentiometer is used as the variable resistance element 522a, the advantages of the digital potentiometer (high precision, high resolution, small size, high stability, long life, high reliability, etc.) can be enjoyed.

[0230] In addition, in the structure shown above Figures 13A - 13C , since the resistance values of the resistance element 422a and the resistance element 422b are fixed, the resistance value of the resistance circuit 420 can only be switched stepwise (discontinuously). In contrast, in the structure shown in Figure 13D or Figure 13E , since the variable resistance element 522a is used, the resistance value of the resistance circuit 420 can be changed continuously. Therefore, the value of the resistance circuit 420 can be finely controlled according to the short-circuit information. For example, when a plurality of LEDs 405 in the same LED column 400 are short-circuited simultaneously, the value of the resistance circuit 420 can be controlled according to the number of short-circuited LEDs 405.

[0231] Figures 14A - 14D is another structural example of the vehicle lamp control device 1. In the vehicle lamp control device 1 shown in Figures 13A - 13E , the resistance value of the resistance circuit 420 is changed by the constant current source 4121 (second constant current source 4121b) of the current source 412. In contrast, in the vehicle lamp control device 1 shown in Figures 14A - 14D , the short-circuit information acquired by the short-circuit information acquisition unit 4125 of the rear lamp lighting control circuit 41 is notified to the rear ECU 23, and the rear ECU 23 sends an instruction to switch the resistance value of the resistance circuit 420 (hereinafter referred to as "resistance value instruction") to the LED substrate 42 based on the notified short-circuit information. The LED substrate 42 switches the resistance value of the resistance circuit 420 based on the resistance value instruction received from the rear ECU 23.

[0232] Figure 14A The resistance circuit 420 in the vehicle lamp control device 1 shown in Figure 13A or Figure 13BThe same as shown. As shown in this figure, the short - circuit information obtained by the short - circuit information acquisition unit 4125 of the rear - lamp lighting control circuit 41 is notified to the rear ECU 23 via a circuit such as a wiring or a communication line. In this example, on the LED substrate 42, there are provided: a communication circuit 431 (such as a CAN transceiver) for receiving the short - circuit information; a decoder circuit 432 for decoding the received short - circuit information; a D / A conversion circuit 433 for converting the decoded digital value into an analog value; and a conduction - breaking control circuit 434 for controlling the conduction and breaking of the switch 423 based on the converted analog value.

[0233] In addition, in the resistance - value indication received by the communication circuit 431, for example, there is a parameter indicating the conduction or breaking of the switch 423. The D / A conversion circuit 433 generates an analog value corresponding to the value of the above - mentioned parameter and inputs it to the conduction - breaking control circuit 434. In this example, the resistance - value control circuit 440 is composed of the communication circuit 431, the decoder circuit 432, the D / A conversion circuit 433, and the conduction - breaking control circuit 434.

[0234] In this way, the structure of controlling the resistance value of the resistance circuit 420 according to the short - circuit information can also be realized by the structure shown in this figure. In addition, in the case of such a structure, the above - mentioned structure can be realized without consuming the resources (constant - current source) of the current source 412.

[0235] In Figure 14B the vehicle lamp control device 1 shown, similar to the case of the vehicle lamp control device 1 shown in Figure 13C the resistance element 422b of the resistance circuit 420 is replaced with a forward - connected diode 424. In this example, the resistance value of the resistance circuit 420 when the switch 423 is conducting can be made zero. In addition, for example, by connecting a resistance element 422b with a resistance value greater than zero in series with the switch 423, the resistance value of the resistance circuit 420 when the switch 423 is conducting can be made a specified value greater than zero. Figure 14A

[0236] In Figure 14C and Figure 14D similar to the vehicle lamp control device 1 shown in Figure 13D and Figure 13E the resistance circuit 420 is constituted by using a variable - resistance element 522a.

[0237] Figure 14C is similar to Figure 13D ​The case where an analog potentiometer is similarly used as the variable resistance element 522a. In this example, on the LED substrate 42, there are provided: a communication circuit 431 (such as a CAN transceiver) that receives a resistance value indication; a decoder circuit 432 that decodes the resistance value indication; and a D / A conversion circuit 433 that converts the decoded digital value into an analog value and inputs it to the analog value input terminal 5221 of the variable resistance element 522a. In the case of this circuit, the resistance value control circuit 440 is composed of the communication circuit 431, the decoder circuit 432, and the D / A conversion circuit 433.

[0238] Figure 14D is the same as Figure 13E The case where a digital potentiometer is similarly used as the variable resistance element 522a. In this example, on the LED substrate 42, there are provided: a communication circuit 431 (such as a CAN transceiver) that receives a resistance value indication; and a decoder circuit 432 that decodes the resistance value indication and inputs the decoded digital value to the digital value input terminal 5222 of the variable resistance element 522a. In the case of this circuit, the resistance value control circuit 440 is composed of the communication circuit 431 and the decoder circuit 432.

[0239] As described above, when a short circuit occurs in the LED 405 in the vehicle lamp control device 1 of the present embodiment, the value of the resistance of the resistance circuit 420 is changed to suppress the change in the value of the voltage (Vk) applied to the first constant current source 4121a. Therefore, even when a short circuit occurs in the LED 405, the value of the voltage applied to the first constant current source 4121a can be maintained within a specified range. Thus, it is possible to prevent an increase in power consumption and heat generation due to an excessive value of the voltage (Vk) applied to the first constant current source 4121a.

[0240] Figure 15 It is a block diagram showing a structural example of the current source 412. The illustrated current source 412 is constituted by, for example, a sink drive IC. As shown in this figure, the illustrated current source 412 includes a communication processing unit 451, an input / output processing unit 452, and a current generation unit 453.

[0241] The communication processing unit 451 functions as, for example, a CAN transceiver. The communication processing unit 451 performs communication with the rear ECU 23, such as sending short circuit information to the rear ECU 23 and receiving information (such as a resistance value indication) sent from the rear ECU 23. The information received by the communication processing unit 451 from the rear ECU 23 is, for example, notified to the current generation unit 453.

[0242] The input / output processing unit 452 includes an analog input processing unit 4521 and a digital input processing unit 4522. The analog input processing unit 4521 receives an analog value input from the outside and notifies the received analog value to the current generation unit 453. The digital input processing unit 4522 receives a digital value input from the outside and notifies the received digital value to the current generation unit 453.

[0243] The current generation unit 453 controls the value of the current output from the constant current source 4121 based on the information (such as resistance value indication) notified by the communication processing unit 451. The current generation unit 453 has a short-circuit information acquisition unit 4125 that acquires the aforementioned short-circuit information.

[0244] As described above, the embodiments of the present invention have been described in detail, but the present invention is not limited to the above-described embodiments and includes various modifications. In addition, the above-described embodiments have described the structure in detail for easy understanding of the present invention, and it is not necessary to be limited to having all the structures described. In addition, for a part of the structure of the above-described embodiments, addition, deletion, and replacement can be made in other structures.

[0245] For example, in the above content, one LED column 400 has been described. However, in the case where a plurality of LED columns 400 are provided on the LED substrate 42, the above-described structure can be applied to each LED column 400.

[0246] As described above, the vehicle lamp control device 1 of the present embodiment includes: a first constant current source that supplies a constant current to a light-emitting element used in a vehicle lamp; a resistance circuit that is connected in series with the light-emitting element and the first constant current source; a current value control circuit that controls the value of the current of the first constant current source; and a resistance value control circuit that changes the resistance value of the resistance circuit to suppress a change in the voltage value applied to the first constant current source when a short circuit occurs in the light-emitting element.

[0247] In this way, when a short circuit occurs in the light-emitting element, the vehicle lamp control device 1 changes the resistance value of the resistance circuit to suppress a change in the voltage value applied to the first constant current source. Therefore, even when a short circuit occurs in the light-emitting element, the voltage value applied to the first constant current source can be maintained within a specified range. Therefore, it is possible to prevent an increase in power consumption and heat generation due to an excessive voltage value applied to the first constant current source caused by a short circuit of the light-emitting element.

[0248] In addition, the vehicle lamp control device 1 of the present embodiment further includes a second constant current source that supplies a current corresponding to whether the light-emitting element is short-circuited, and the resistance value control circuit changes the resistance value of the resistance circuit according to the value of the current supplied by the second constant current source.

[0249] Thus, the vehicle lamp control device 1 uses one of the constant current sources (second constant current source) of a current source (such as a driving IC) having a plurality of constant current sources to change the resistance value of the resistance circuit. Therefore, a structure that controls the resistance value of the resistance circuit according to the short circuit of the light emitting element can be realized with a simple structure.

[0250] In addition, the above-mentioned resistance circuit of the vehicle lamp control device 1 of the present embodiment includes: a first resistance element connected in series with the light emitting element; and a second resistance element and a switch connected in series with the light emitting element and connected in parallel with the first resistance element. The above-mentioned resistance value control circuit turns on and off the switch according to the current value of the second constant current source.

[0251] According to the above structure, a structure that controls the resistance value of the resistance circuit according to the short circuit of the light emitting element can be realized with a simple structure.

[0252] In addition, the above-mentioned resistance circuit of the vehicle lamp control device 1 of the present embodiment includes: a first resistance element connected in series with the light emitting element; and a diode and a switch connected in series with the light emitting element in the forward direction and connected in parallel with the first resistance element. The above-mentioned resistance value control circuit turns on and off the switch according to the current value of the second constant current source.

[0253] According to the above structure, a structure that controls the resistance value of the resistance circuit according to the short circuit of the light emitting element can be realized with a simple structure. In addition, the resistance value of the resistance circuit can be made zero by energizing the diode.

[0254] In addition, the above-mentioned resistance circuit of the vehicle lamp control device 1 of the present embodiment includes a variable resistance element whose resistance value changes according to a control voltage. The above-mentioned resistance value control circuit outputs a control voltage corresponding to the current value of the second constant current source.

[0255] Thus, by using the variable resistance element, a structure that controls the resistance value of the resistance circuit according to the short circuit of the light emitting element can be realized with a simple structure.

[0256] In addition, the first constant current source and the second constant current source of the vehicle lamp control device 1 of the present embodiment are different constant current sources of an integrated circuit having a plurality of constant current sources.

[0257] Therefore, an integrated circuit such as a driving IC having a plurality of constant current sources can be used to realize a structure that controls the resistance value of the resistance circuit according to the short circuit of the light emitting element with a simple structure.

[0258] In addition, the vehicle lamp control device 1 of the present embodiment further includes: a short-circuit information acquisition unit that acquires short-circuit information indicating whether a light-emitting element is short-circuited; a notification circuit that notifies the short-circuit information to other devices communicably connected; and a reception circuit that receives a resistance value instruction notified by other devices based on the short-circuit information, where the resistance value instruction is used to indicate the value of the resistance of the above resistance circuit, and the above resistance value control circuit changes the value of the resistance of the above resistance circuit according to the resistance value instruction received by the reception circuit.

[0259] Thus, according to the above structure, other devices such as the rear ECU directly control the value of the resistance of the resistance circuit. Therefore, a structure can be realized in which the value of the resistance of the resistance circuit changes according to the short circuit of the light-emitting element without consuming the resources (constant current source) of the current source (driver IC).

[0260] Description of reference numerals:

[0261] 1: Vehicle lamp control device; 2: Vehicle; 5: Operator terminal; 6: Battery; 21: Central ECU; 22: Front ECU; 23: Rear ECU; 30: Headlamp; 40: Rear lamp; 41: Rear lamp lighting control circuit; 411: Voltage source; 412: Current source; 4121: Constant current source; 4121a: First constant current source; 4121b: Second constant current source; 4125: Short-circuit information acquisition unit; 42: LED substrate; 45: Temperature sensor; 400: LED column; 405: LED; 420: Resistance circuit; 422: Resistance element; 422a: Resistance element; 422b: Resistance element; 422c: Resistance element; 422d: Resistance element; 423: Switch; 424: Diode; 522a: Variable resistance element; 522b: Resistance element; 522c: Resistance element; 525: A / D conversion circuit; 431: Communication circuit; 432: Decoder circuit; 433: D / A conversion circuit; 434: Conductivity on / off control circuit; 451: Communication processing unit; 452: Input / output processing unit; 453: Current generation unit.

Claims

1. A lighting control device for a vehicle, comprising: A first constant current source that supplies a constant current to a light-emitting element used in a vehicle lamp; A resistance circuit connected in series with the light-emitting element and the first constant current source; A current value control circuit that controls the value of the current of the first constant current source according to a lighting state indication indicating the lighting state of the light-emitting element; and A resistance value control circuit that changes the resistance value of the resistance circuit to suppress a change in the voltage value applied to the first constant current source when the value of the current supplied to the light-emitting element changes.

2. The lighting control device for a vehicle according to claim 1, characterized in that: It further comprises a second constant current source that supplies a current corresponding to the lighting state indication, The resistance value control circuit changes the resistance value of the resistance circuit according to the value of the current supplied by the second constant current source.

3. The lighting control device for a vehicle according to claim 2, characterized in that: The resistance circuit includes: A first resistance element connected in series with the light-emitting element; and A second resistance element and a switch connected in series with the light-emitting element and in parallel with the first resistance element, The resistance value control circuit turns on and off the switch according to the value of the current of the second constant current source.

4. The lighting control device for a vehicle according to claim 2, characterized in that: The resistance circuit includes: A first resistance element connected in series with the light-emitting element; and A diode and a switch connected in series with the light-emitting element in the forward direction and in parallel with the first resistance element, The resistance value control circuit turns on and off the switch according to the value of the current of the second constant current source.

5. The lighting control device for a vehicle according to claim 2, characterized in that: The resistance circuit includes a variable resistance element whose resistance value changes according to a control voltage, The resistance value control circuit outputs the control voltage corresponding to the value of the current of the second constant current source.

6. The lighting control device for a vehicle according to claim 2, characterized in that: The first constant current source and the second constant current source are different constant current sources of an integrated circuit having a plurality of constant current sources respectively.

7. The lighting control device for a vehicle according to claim 1, characterized in that: It further comprises a receiving circuit that receives the lighting state indication from another device communicably connected, The resistance value control circuit changes the resistance value of the resistance circuit according to the lighting state indication received by the receiving circuit.

8. The lighting control device for a vehicle according to claim 7, characterized in that: The resistance circuit includes: A first resistance element connected in series with the light-emitting element; and A second resistance element and a switch connected in series with the light-emitting element and in parallel with the first resistance element, The resistance value control circuit turns on and off the switch according to the lighting state indication.

9. The lighting control device for a vehicle according to claim 7, characterized in that: The resistance circuit includes: A first resistance element connected in series with the light-emitting element; and A diode and a switch connected in series with the light-emitting element in the forward direction and connected in parallel with the first resistance element, The resistance value control circuit turns on and off the switch according to the lighting state indication.

10. The vehicle lamp control device according to claim 7, characterized in that, The resistance circuit includes a variable resistance element whose resistance value changes according to a control voltage, The resistance value control circuit outputs the control voltage.

11. The vehicle lamp control device according to claim 1, characterized in that, A second information processing device is provided, and the second information processing device is communicably connected to the first information processing device, The second information processing device Stores software for implementing the process of generating the lighting state indication, Receives update information of the software from the first information processing device, Based on the received update information, updates the software to change the value of the current supplied to the light-emitting element before and after the update.

12. The vehicle lamp control device according to claim 1, characterized in that, The vehicle lamp is a rear lamp, The light-emitting element constitutes the light source of the rear lamp.

13. A vehicle lamp control device, comprising: A first constant current source that supplies a constant current to a light-emitting element used in a vehicle lamp; A resistance circuit connected in series with the light-emitting element and the first constant current source; A current value control circuit that controls the current value of the first constant current source; and A resistance value control circuit that changes the resistance value of the resistance circuit to suppress a change in the voltage value applied to the first constant current source when the temperature around the light-emitting element changes.

14. The vehicle lamp control device according to claim 13, characterized in that, It further includes a second constant current source that supplies a current corresponding to the temperature around the light-emitting element, The resistance value control circuit changes the resistance value of the resistance circuit according to the current value supplied by the second constant current source.

15. The vehicle lamp control device according to claim 14, characterized in that, The resistance circuit includes: A first resistance element connected in series with the light-emitting element; and A second resistance element and a switch connected in series with the light-emitting element and connected in parallel with the first resistance element, The resistance value control circuit turns on and off the switch according to the current value of the second constant current source.

16. The vehicle lamp control device according to claim 14, characterized in that, The resistance circuit includes: A first resistance element connected in series with the light-emitting element; and A diode and a switch connected in series with the light-emitting element in the forward direction and connected in parallel with the first resistance element, The resistance value control circuit turns on and off the switch according to the current value of the second constant current source.

17. The vehicle lamp control device according to claim 14, characterized in that, The resistance circuit includes a variable resistance element whose resistance value changes according to a control voltage, The resistance value control circuit outputs the control voltage corresponding to the value of the current of the second constant current source.

18. The vehicle lamp control device according to claim 14, wherein: The first constant current source and the second constant current source are different constant current sources of an integrated circuit including a plurality of constant current sources, respectively.

19. The vehicle lamp control device according to claim 13, characterized in that, It further includes: A temperature information acquisition circuit that acquires temperature information indicating the temperature around the light-emitting element; A notification circuit that notifies the temperature information to other devices communicably connected; And A reception circuit that receives a resistance value indication notified by the other device based on the temperature information, the resistance value indication being used to indicate the value of the resistance of the resistance circuit, The resistance value control circuit changes the value of the resistance of the resistance circuit according to the resistance value indication received by the reception circuit.

20. The vehicle lamp control device according to claim 19, wherein: The resistance circuit includes: A first resistance element connected in series with the light-emitting element; and A second resistance element and a switch connected in series with the light-emitting element and in parallel with the first resistance element, The resistance value control circuit turns on and off the switch according to the resistance value indication.

21. The vehicle lamp control device according to claim 19, wherein: The resistance circuit includes: A first resistance element connected in series with the light-emitting element; and A diode and a switch connected in series and forward-connected with the light-emitting element and in parallel with the first resistance element, The resistance value control circuit turns on and off the switch according to the resistance value indication.

22. The vehicle lamp control device according to claim 19, wherein: The resistance circuit includes a variable resistance element whose resistance value changes according to a control voltage, The resistance value control circuit outputs the control voltage.

23. The vehicle lamp control device according to claim 13, wherein: The vehicle lamp is a rear lamp, The light-emitting element constitutes the light source of the rear lamp.

24. A vehicle lamp control device, comprising: A first constant current source that supplies a constant current to a light-emitting element used in a vehicle lamp; A resistance circuit connected in series with the light-emitting element and the first constant current source; A current value control circuit that controls the value of the current of the first constant current source; and A resistance value control circuit that changes the value of the resistance of the resistance circuit to suppress a change in the value of the voltage applied to the first constant current source when the light-emitting element is short-circuited.

25. The vehicle lamp control device according to claim 24, wherein: It further includes a second constant current source that supplies a current corresponding to whether the light-emitting element is short-circuited, The resistance value control circuit changes the value of the resistance of the resistance circuit according to the value of the current supplied by the second constant current source.

26. The vehicle lamp control device according to claim 25, wherein: The resistance circuit includes: A first resistance element connected in series with the light-emitting element; and A second resistor element and a switch, which are connected in series with the light-emitting element and in parallel with the first resistor element, The resistance value control circuit turns the switch on and off according to the value of the current of the second constant current source.

27. The vehicle lamp control device according to claim 25, characterized in that The resistance circuit includes: A first resistor element, which is connected in series with the light-emitting element; and A diode and a switch, which are connected in series with the light-emitting element in the forward direction and in parallel with the first resistor element, The resistance value control circuit turns the switch on and off according to the value of the current of the second constant current source.

28. The vehicle lamp control device according to claim 25, characterized in that The resistance circuit includes a variable resistor element whose resistance value changes according to a control voltage, The resistance value control circuit outputs the control voltage corresponding to the value of the current of the second constant current source.

29. The vehicle lamp control device according to claim 25, characterized in that The first constant current source and the second constant current source are respectively different constant current sources of an integrated circuit having a plurality of constant current sources.

30. The vehicle lamp control device according to claim 24, wherein It further includes: A short-circuit information acquisition unit, which acquires short-circuit information indicating whether the light-emitting element is short-circuited; A notification circuit, which notifies the short-circuit information to other devices that are communicably connected; And A receiving circuit, which receives a resistance value indication notified by the other device based on the short-circuit information, and the resistance value indication is used to indicate the resistance value of the resistance circuit, The resistance value control circuit changes the resistance value of the resistance circuit according to the resistance value indication received by the receiving circuit.

31. The vehicle lamp control device according to claim 30, characterized in that The resistance circuit includes: A first resistor element, which is connected in series with the light-emitting element; and A second resistor element and a switch, which are connected in series with the light-emitting element and in parallel with the first resistor element, The resistance value control circuit turns the switch on and off according to the resistance value indication.

32. The vehicle lamp control device according to claim 30, characterized in that The resistance circuit includes: A first resistor element, which is connected in series with the light-emitting element; and A diode and a switch, which are connected in series with the light-emitting element in the forward direction and in parallel with the first resistor element, The resistance value control circuit turns the switch on and off according to the resistance value indication.

33. The vehicle lamp control device according to claim 30, characterized in that The resistance circuit includes a variable resistor element whose resistance value changes according to a control voltage, The resistance value control circuit outputs the control voltage.

34. The vehicle lamp control device according to claim 24, characterized in that The vehicle lamp is a rear lamp, The light-emitting element constitutes the light source of the rear lamp.

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