JP7109700B2 - Control device - Google Patents

Description

The present disclosure relates to a headlamp control device.

2. Description of the Related Art Conventionally, a plurality of light emitting diodes (hereinafter referred to as "LEDs") connected in series are used as a light source for a headlamp. A group including a plurality of LEDs (hereinafter referred to as "LED group") is divided into a plurality of segments. A plurality of segments can be lit independently of each other. That is, a plurality of segments can be lit individually. As a result, multiple types of light distribution are realized. Specifically, for example, light distribution for low beam and light distribution for high beam are realized. Also, for example, a light distribution for a so-called "variable light distribution headlamp" is realized. Also, for example, a light distribution for a so-called "link indicator" is realized.

In such headlamps, techniques have been developed to detect faults in individual segments. For example, Patent Literature 1 discloses a technique of detecting failures in individual segments using a plurality of voltage detectors corresponding to a plurality of segments.

JP 2007-112237 A

In the technique described in Patent Document 1, a plurality of voltage detectors are provided in a headlamp lighting device. This increases the circuit scale of the lighting device. In other words, there is a problem that it is difficult to reduce the circuit scale of the lighting device.

The present disclosure has been made to solve the above-described problems, and aims to reduce the circuit scale of a lighting device when detecting failures in individual segments.

A control device according to the present disclosure is a control device for a headlight having an LED group including a plurality of segments, and includes a voltage estimating unit that calculates a voltage estimation value corresponding to each segment, and a power supply circuit for the LED group. corresponding to each segment using a shift processing unit that shifts the current supply timing for each segment by a different amount of shift, and a voltage detector that detects the output voltage of the power supply circuit according to the shift processing. and a fault detection section for executing fault detection processing for judging the presence or absence of a fault in each segment by comparing each detected voltage value with the corresponding estimated voltage value. The shift processing and the failure detection processing are executed when the headlights start lighting .

According to the present disclosure, since it is configured as described above, it is possible to reduce the number of voltage detectors in the lighting device when detecting failures in individual segments. As a result, the circuit scale of the lighting device can be reduced.

FIG. 2 is an explanatory diagram showing a main part of the headlamp including the control device according to Embodiment 1; FIG. 2 is a block diagram showing the main part of the control device according to Embodiment 1; FIG. FIG. 4 is an explanatory diagram showing an example of a characteristic table corresponding to characteristic information; FIG. 7 is an explanatory diagram showing an example of shift processing by shifting the control cycle; FIG. 10 is an explanatory diagram showing an example of shift processing due to a decrease in duty ratio; FIG. 11 is an explanatory diagram showing another example of shift processing by shifting the control period; FIG. 10 is an explanatory diagram showing another example of shift processing due to reduction in duty ratio; 2 is a block diagram showing the hardware configuration of main parts of the control device according to Embodiment 1; FIG. 4 is a block diagram showing another hardware configuration of the main part of the control device according to Embodiment 1; FIG. 4 is a block diagram showing another hardware configuration of the main part of the control device according to Embodiment 1; FIG. 4 is a flow chart showing operations in a failure detection mode of the control device according to Embodiment 1; 4 is a flow chart showing operations in a failure detection mode of the control device according to Embodiment 1; FIG. 4 is an explanatory diagram showing main parts of a headlamp including another control device according to Embodiment 1; FIG. 11 is an explanatory diagram showing another example of shift processing by shifting the control period; FIG. 10 is an explanatory diagram showing another example of shift processing due to reduction in duty ratio; FIG. 11 is an explanatory diagram showing another example of shift processing by shifting the control period; FIG. 10 is an explanatory diagram showing another example of shift processing due to reduction in duty ratio; 9 is a flow chart showing the operation in the normal lighting mode of the control device according to Embodiment 2;

Hereinafter, in order to describe this disclosure in more detail, embodiments for implementing this disclosure will be described with reference to the accompanying drawings.

Embodiment 1.
FIG. 1 is an explanatory diagram showing a main part of a headlamp including a control device according to Embodiment 1. FIG. A headlamp including a control device according to Embodiment 1 will be described with reference to FIG.

The headlamp 100 is provided on a vehicle (not shown). A light source of the headlamp 100 is composed of an LED group 1 . The LED group 1 is divided into a plurality of segments SG. Each segment SG includes one LED 2 or multiple LEDs 2 connected in series. An example in which the LED group 1 is divided into three segments SG_1, SG_2, and SG_3 will be mainly described below. Segment SG_1 includes, for example, eight LEDs 2 connected in series with each other. Segment SG_2 includes, for example, three LEDs 2 connected in series with each other. Segment SG_3 contains one LED2, for example.

The headlamp 100 has a lighting device 200 for the LED group 1 . The lighting device 200 includes a power supply circuit 3 . The power supply circuit 3 is configured by, for example, a DC/DC converter. The power supply circuit 3 supplies current to the LED group 1 by constant current control. That is, the power supply circuit 3 supplies a predetermined current to the LED group 1 .

The lighting device 200 includes a switch circuit group 4 . The switch circuit group 4 includes a plurality of switch circuits 5 corresponding to a plurality of segments SG. An example in which the switch circuit group 4 includes three switch circuits 5_1, 5_2, and 5_3 corresponding to the three segments SG_1, SG_2, and SG_3 will be mainly described below.

The lighting device 200 includes a drive circuit 6 . The drive circuit 6 drives one or more selected switch circuits 5 out of the plurality of switch circuits 5 by PWM (Pulse Width Modulation) control. That is, the drive circuit 6 can drive the plurality of switch circuits 5 independently of each other. In other words, the drive circuit 6 is capable of individually driving the plurality of switch circuits 5 .

When each switch circuit 5 is in the ON state, the corresponding segment SG is bypassed so that the predetermined current does not flow through the corresponding segment SG. As a result, the state of the corresponding segment SG is turned off. On the other hand, when each switch circuit 5 is in the OFF state, the corresponding segment SG is not bypassed, so that the above defined current flows through the corresponding segment SG. As a result, the state of the corresponding segment SG is turned on.

As a result, multiple types of light distribution are realized. Specifically, for example, the LED group 1 includes one or more segments SG corresponding to light distribution for low beam. A low beam light distribution is realized by lighting the one or more segments SG. Further, for example, the LED group 1 includes one or more segments SG corresponding to light distribution for high beam. Light distribution for high beam is achieved by lighting the one or more segments SG.

The lighting device 200 includes a control device 300 . Control device 300 can communicate with an electronic control unit (hereinafter referred to as “ECU”) 400 . The ECU 400 is provided inside the vehicle and outside the headlamp 100 . ECU 400 is a superior ECU for control device 300 .

ECU 400 transmits a lighting instruction signal S<b>1 for headlamp 100 to control device 300 . The control device 300 receives the transmitted lighting instruction signal S1. The lighting instruction signal S1 is, for example, a signal that instructs lighting of the headlamp 100 with one type of light distribution selected from among the plurality of types of light distribution. In other words, the lighting instruction signal S1 is, for example, a signal that instructs lighting of one or more selected segments SG among the plurality of segments SG.

The control device 300 outputs a control signal (hereinafter referred to as “first control signal”) S2 for realizing the constant current control to the power supply circuit 3 according to the content of the lighting instruction signal S1. That is, the control device 300 outputs the first control signal S2 for realizing the constant current control to the power supply circuit 3 according to the number of the LEDs 2 to be lit with the light distribution indicated by the lighting instruction signal S1. . In other words, the control device 300 controls the power supply circuit 3 by outputting the first control signal S2 to the power supply circuit 3 .

The control device 300 outputs a control signal (hereinafter referred to as “second control signal”) S3 for realizing the PWM control to the drive circuit 6 according to the contents of the lighting instruction signal S1. That is, the control device 300 outputs the second control signal S3 for realizing the PWM control to the drive circuit 6 according to the segment SG to be lit with the light distribution indicated by the lighting instruction signal S1. In other words, the control device 300 controls the drive circuit 6 by outputting the second control signal S3 to the drive circuit 6 .

As a result, lighting of the LED group 1 according to the content of the lighting instruction signal S1 is realized. That is, lighting of the headlamp 100 with the light distribution instructed by the ECU 400 is realized.

Thus, control device 300 has an operation mode (hereinafter referred to as "normal lighting mode") for executing control for lighting headlamp 100 (hereinafter referred to as "lighting control") in accordance with an instruction from ECU 400. ing. Various known techniques can be used for controlling the power supply circuit 3 and the drive circuit 6 by the control device 300 in the normal lighting mode. A detailed description of these techniques is omitted.

In addition to this, the control device 300 has an operation mode (hereinafter referred to as "failure detection mode") for detecting failures in individual segments SG. The failure detection mode will be described below with reference to FIGS. 1 to 7. FIG.

As shown in FIG. 1, lighting device 200 includes voltage detector 7 . As shown in FIG. 2, the control device 300 includes a voltage estimator 11, a shift processor 12, a voltage detector 13 and a failure detector .

A voltage detector 7 continuously detects the output voltage V1 of the power supply circuit 3 .

The voltage estimator 11 executes a process (hereinafter referred to as a "voltage estimation process") of calculating an estimated voltage value (hereinafter referred to as a "voltage estimated value") V2 corresponding to each segment SG. The estimated voltage value V2 is calculated based on information indicating the voltage characteristics of each segment SG (hereinafter referred to as "characteristic information"). The characteristic information is stored in advance in the voltage estimator 11, for example. FIG. 3 shows an example of a characteristic table corresponding to characteristic information.

The shift processing unit 12 executes processing (hereinafter referred to as “shift processing”) for shifting the current supply timing to the LED group 1 by the power supply circuit 3 by a shift amount δ that differs for each segment SG. The shift processing is realized by shifting the control period ΔT in the PWM control by a shift amount δ that differs for each segment SG. Alternatively, the shift process is realized by temporarily lowering the duty ratio DR in the PWM control by a different lowering amount δ for each segment SG. That is, the second control signal S3 is used for the shift processing.

The shift process is performed at the timing when the headlamp 100 starts lighting (hereinafter sometimes referred to as "first timing") or the timing when the content of the lighting instruction to the headlamp 100 changes (hereinafter referred to as "second timing"). ) is executed at least one timing. That is, the second timing is the timing when the content of the lighting instruction signal S1 changes while the headlamp 100 is on. In other words, the second timing is the timing at which the light distribution instructed by the ECU 400 changes while the headlamp 100 is on.

The voltage detection unit 13 performs a process (hereinafter referred to as a "voltage detection process") for sequentially calculating a voltage detection value (hereinafter referred to as a "voltage detection value") V3 corresponding to each segment SG according to the shift process. to execute. The voltage detection value V3 is calculated using the output voltage V1 detected by the voltage detector 7. FIG.

The failure detection unit 14 compares each detected voltage value V3 with the corresponding estimated voltage value V2 to determine whether there is a failure in each segment SG (hereinafter referred to as "failure detection process"). is. Thereby, faults in individual segments SG are detected.

For each segment SG, when it is determined that the segment SG has a failure, the control device 300 stores information indicating the segment SG (hereinafter referred to as "failure segment information"). That is, the failure segment information is information indicating the segment SG in failure. Control device 300 transmits to ECU 400 a signal (hereinafter referred to as "failure notification signal") S4 corresponding to the failure segment information. ECU 400 receives the transmitted failure notification signal S4.

In response to this, the ECU 400 transmits to the control device 300, for example, a lighting instruction signal S1 instructing to turn off the headlamp 100. FIG. Such lighting instruction signal S1 is transmitted, for example, when all segments SG are out of order. Alternatively, the ECU 400 transmits to the control device 300, for example, a lighting instruction signal S1 instructing to turn off the malfunctioning segment SG. Such a lighting instruction signal S1 is transmitted, for example, when only some segments SG are out of order. Further, the ECU 400 executes control for notifying the driver of the vehicle that, for example, the failure of the headlight 100 makes it impossible to realize the light distribution corresponding to the failed segment SG.

Specific examples of voltage estimation processing, shift processing, voltage detection processing, and failure detection processing will now be described with reference to FIGS. It is assumed that the lighting instruction signal S1 after time t0 instructs lighting of all the segments SG_1, SG_2, and SG_3. It is also assumed that no failure has occurred in any segment SG. In other words, assume that all segments SG are normal.

<First specific example (see FIG. 4)>
In the first specific example, the duty ratio DR_1 corresponding to the segment SG_1 is set to 100%, the duty ratio DR_2 corresponding to the segment SG_2 is set to 100%, and the duty ratio DR_2 corresponding to the segment SG_3 is set to 100%. Duty ratio DR_3 is set to 100%. The shift processing in the first specific example shifts the control cycle ΔT by a different shift amount δ for each segment SG. In the figure, each of ΔT_1, ΔT_2 and ΔT_3 corresponds to one cycle of PWM.

The voltage estimator 11 calculates an estimated voltage value V2_1 corresponding to the segment SG_1, an estimated voltage value V2_2 corresponding to the segment SG_2, and an estimated voltage value V2_3 corresponding to the segment SG_3 based on the characteristic information.

Time t0 corresponds to the first timing or the second timing. At time t0, shift processing is started. That is, the shift processing unit 12 executes processing to shift the control period ΔT_1 corresponding to the segment SG_1 by the shift amount δ_1 (δ_1=0). Further, the shift processing unit 12 executes processing to shift the control period ΔT_2 corresponding to the segment SG_2 by the shift amount δ_2 (δ_2>δ_1). Further, the shift processing unit 12 executes processing to shift the control period ΔT_3 corresponding to the segment SG_3 by the shift amount δ_3 (δ_3>δ_2).

At time t1, the switch circuit 5_1 is in the OFF state, and the switch circuits 5_2 and 5_3 are in the ON state. Therefore, the voltage detection unit 13 uses the output voltage V1_1 detected by the voltage detector 7 at the time t1 to calculate the voltage detection value V3_1 corresponding to the segment SG_1. That is, the voltage detection value V3_1 is calculated by the following equation (1).

V3_1=V1_1 (1)

At time t2, switch circuits 5_1 and 5_2 are off, and switch circuit 5_3 is on. Therefore, the voltage detection unit 13 uses the output voltage V1_1 detected by the voltage detector 7 at the time t1 and the output voltage V1_2 detected by the voltage detector 7 at the time t2 to detect the segment SG_2. A voltage detection value V3_2 is calculated. That is, the voltage detection value V3_2 is calculated by the following equation (2).

V3_2=V1_2-V1_1 (2)

At time t3, switch circuits 5_1, 5_2, and 5_3 are off. Therefore, the voltage detection unit 13 uses the output voltage V1_2 detected by the voltage detector 7 at the time t2 and the output voltage V1_3 detected by the voltage detector 7 at the time t3 to detect the segment SG_3. A voltage detection value V3_3 is calculated. That is, the voltage detection value V3_3 is calculated by the following equation (3).

V3_3=V1_3-V1_2 (3)

In this manner, the voltage detection value V3_1, the voltage detection value V3_2, and the voltage detection value V3_3 are sequentially calculated.

The failure detection unit 14 calculates a difference value ΔV_1 between the calculated voltage detection value V3_1 and the calculated voltage estimated value V2_1. The failure detection unit 14 determines whether the calculated difference value ΔV_1 is within a predetermined range (hereinafter referred to as “reference range”) Vth. When the calculated difference value ΔV_1 is within the reference range Vth, the failure detection unit 14 determines that there is no failure in the segment SG_1. Otherwise, the fault detector 14 determines that there is a fault in the segment SG_1.

Further, the failure detection unit 14 calculates a difference value ΔV_2 between the calculated voltage detection value V3_2 and the calculated voltage estimated value V2_2. The failure detection unit 14 determines whether the calculated difference value ΔV_2 is a value within the reference range Vth. When the calculated difference value ΔV_2 is within the reference range Vth, the failure detection unit 14 determines that there is no failure in the segment SG_2. Otherwise, the fault detector 14 determines that there is a fault in segment SG_2.

Further, the failure detection unit 14 calculates a difference value ΔV_3 between the calculated voltage detection value V3_3 and the calculated voltage estimated value V2_3. The failure detection unit 14 determines whether the calculated difference value ΔV_3 is a value within the reference range Vth. When the calculated difference value ΔV_3 is a value within the reference range Vth, the failure detection unit 14 determines that there is no failure in the segment SG_3. Otherwise, the fault detector 14 determines that there is a fault in the segment SG_3.

Thus, it is determined whether there is a failure in each of the segments SG_1, SG_2, and SG_3.

<Second specific example (see FIG. 5)>
In the second specific example, the duty ratio DR_1 is set to 100%, the duty ratio DR_2 is set to 100%, and the duty ratio DR_3 is set to 100%. The shift process in the second specific example temporarily lowers the duty ratio DR by a different amount of reduction δ for each segment SG. In the figure, ΔT corresponds to one cycle of PWM.

The voltage estimation process in the second specific example is the same as the voltage estimation process in the first specific example. Therefore, repetitive description is omitted.

At time t0, shift processing is started. That is, the shift processing unit 12 executes processing to temporarily decrease the duty ratio DR_1 by the decrease amount δ_1 (δ_1=0). Further, the shift processing unit 12 executes processing to temporarily decrease the duty ratio DR_2 by a decrease amount δ_2 (δ_2>δ_1). Further, the shift processing unit 12 executes a process of temporarily decreasing the duty ratio DR_3 by a decrease amount δ_3 (δ_3>δ_2).

As a result, the duty ratio DR_2 temporarily drops to a value (eg, 80%) lower than the set value (ie, 100%). Also, the duty ratio DR_3 temporarily decreases to a value (eg, 60%) lower than the set value (ie, 100%).

As a result, at time t1, the switch circuit 5_1 is in the OFF state, and the switch circuits 5_2 and 5_3 are in the ON state. At time t2, the switch circuits 5_1 and 5_2 are in the OFF state, and the switch circuit 5_3 is in the ON state. At time t3, the switch circuits 5_1, 5_2, and 5_3 are in the off state.

Therefore, the voltage detection unit 13 executes voltage detection processing similar to the voltage detection processing in the first specific example. Thereby, the voltage detection value V3_1, the voltage detection value V3_2, and the voltage detection value V3_3 are sequentially calculated.

The failure detection process in the second specific example is the same as the failure detection process in the first specific example. Therefore, repetitive description is omitted.

<Third specific example (see FIG. 6)>
In the third specific example, the duty ratio DR_1 is set to 80%, the duty ratio DR_2 is set to 70%, and the duty ratio DR_3 is set to 60%. The shift processing in the third specific example shifts the control cycle ΔT by a different shift amount δ for each segment SG. In the figure, each of ΔT_1, ΔT_2 and ΔT_3 corresponds to one cycle of PWM.

The voltage estimation process in the third specific example is the same as the voltage estimation process in the first specific example. Therefore, repetitive description is omitted.

At time t0, shift processing is started. That is, the shift processing unit 12 executes processing to shift the control period ΔT_1 by the shift amount δ_1 (δ_1=0). Further, the shift processing unit 12 executes processing to shift the control period ΔT_2 by a shift amount δ_2 (δ_2>δ_1). Further, the shift processing unit 12 executes processing to shift the control period ΔT_3 by a shift amount δ_3 (δ_3>δ_2).

As a result, at time t1, the switch circuit 5_1 is in the OFF state, and the switch circuits 5_2 and 5_3 are in the ON state. At time t2, the switch circuits 5_1 and 5_2 are in the OFF state, and the switch circuit 5_3 is in the ON state. At time t3, the switch circuits 5_1, 5_2, and 5_3 are in the off state.

Therefore, the voltage detection unit 13 executes voltage detection processing similar to the voltage detection processing in the first specific example. Thereby, the voltage detection value V3_1, the voltage detection value V3_2, and the voltage detection value V3_3 are sequentially calculated.

The failure detection process in the third specific example is the same as the failure detection process in the first specific example. Therefore, repetitive description is omitted.

<Fourth specific example (see FIG. 7)>
In the fourth specific example, the duty ratio DR_1 is set at 80%, the duty ratio DR_2 is set at 70%, and the duty ratio DR_3 is set at 60%. The shift process in the fourth specific example temporarily lowers the duty ratio DR by a different amount of reduction δ for each segment SG. In the figure, ΔT corresponds to one cycle of PWM.

The voltage estimation process in the fourth specific example is the same as the voltage estimation process in the first specific example. Therefore, repetitive description is omitted.

At time t0, shift processing is started. That is, the shift processing unit 12 executes processing to temporarily decrease the duty ratio DR_1 by the decrease amount δ_1 (δ_1=0). Further, the shift processing unit 12 executes processing to temporarily decrease the duty ratio DR_2 by a decrease amount δ_2 (δ_2>δ_1). Further, the shift processing unit 12 executes a process of temporarily decreasing the duty ratio DR_3 by a decrease amount δ_3 (δ_3>δ_2).

As a result, the duty ratio DR_2 temporarily decreases to a value (eg, 50%) lower than the set value (eg, 70%). Also, the duty ratio DR_3 temporarily decreases to a value (eg, 20%) lower than the set value (ie, 60%).

As a result, at time t1, the switch circuit 5_1 is in the OFF state, and the switch circuits 5_2 and 5_3 are in the ON state. At time t2, the switch circuits 5_1 and 5_2 are in the OFF state, and the switch circuit 5_3 is in the ON state. At time t3, the switch circuits 5_1, 5_2, and 5_3 are in the off state.

Therefore, the voltage detection unit 13 executes voltage detection processing similar to the voltage detection processing in the first specific example. Thereby, the voltage detection value V3_1, the voltage detection value V3_2, and the voltage detection value V3_3 are sequentially calculated.

The failure detection process in the fourth specific example is the same as the failure detection process in the first specific example. Therefore, repetitive description is omitted.

Note that in the second specific example and the fourth specific example, the duty ratios DR_2 and DR_3 are temporarily lowered by executing the shift process. In other words, some of the segments SG_1, SG_2, and SG_3 that should be lit are temporarily not lit, so that the brightness of the headlamp 100 is temporarily reduced. On the other hand, each of the shift amounts δ_1, δ_2, δ_3 is set to a sufficiently small value. This makes it possible to avoid such a decrease in brightness being perceived by humans.

Hereinafter, the plurality of functions of the control device 300 (including the functions of the voltage estimation unit 11, the shift processing unit 12, the voltage detection unit 13, and the failure detection unit 14) are collectively referred to simply as "multiple functions". It is sometimes called "individual function". Also, the "F" designation may be used for such functions.

Next, the hardware configuration of main parts of the control device 300 will be described with reference to FIGS. 8 to 10. FIG.

As shown in FIG. 8, the control device 300 has a processor 21 and a memory 22 . Programs corresponding to a plurality of functions F are stored in the memory 22 . The processor 21 reads and executes programs stored in the memory 22 . Thereby, a plurality of functions F are realized.

Alternatively, the control device 300 has a processing circuit 23 as shown in FIG. The processing circuit 23 executes processing corresponding to a plurality of functions F. FIG. Thereby, a plurality of functions F are realized.

Alternatively, as shown in FIG. 10, the control device 300 has a processor 21, a memory 22 and a processing circuit . The memory 22 stores programs corresponding to some of the functions F. FIG. The processor 21 reads and executes programs stored in the memory 22 . This implements some of these functions. The processing circuit 23 also executes processing corresponding to the remaining functions among the plurality of functions F. FIG. This implements such residual functionality.

The processor 21 is composed of one or more processors. The individual processors are, for example, CPUs (Central Processing Units), GPUs (Graphics Processing Units), microprocessors, microcontrollers or DSPs (Digital Signal Processors).

The memory 22 is composed of one or more nonvolatile memories. Alternatively, the memory 22 is composed of one or more nonvolatile memories and one or more volatile memories. That is, the memory 22 is composed of one or more memories. Each memory uses, for example, a semiconductor memory or a magnetic disk. More specifically, each volatile memory uses RAM (Random Access Memory), for example. In addition, individual nonvolatile memory, for example, ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), those using a solid state drive or hard disk drive is.

The processing circuit 23 is composed of one or more digital circuits. Alternatively, the processing circuit 23 is composed of one or more digital circuits and one or more analog circuits. That is, the processing circuit 23 is composed of one or more processing circuits. Individual processing circuits are, for example, ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), FPGA (Field Programmable Gate Array), SoC (System on a Chip), or system LSI (Large Scale) is.

Here, when the processor 21 is composed of a plurality of processors, the correspondence relationship between the plurality of functions F and the plurality of processors is arbitrary. That is, each of the plurality of processors may read and execute a program corresponding to one or more functions among the plurality of functions F. The processor 21 may include dedicated processors corresponding to individual functions F.

Moreover, when the memory 22 is composed of a plurality of memories, the correspondence relationship between the plurality of functions F and the plurality of memories is arbitrary. That is, each of the plurality of memories may store a program corresponding to one or more corresponding functions among the plurality of functions F. Memory 22 may include dedicated memory corresponding to individual functions F. FIG.

Further, when the processing circuit 23 is composed of a plurality of processing circuits, the correspondence relationship between the plurality of functions F and the plurality of processing circuits is arbitrary. That is, each of the plurality of processing circuits may execute processing corresponding to one or more corresponding functions among the plurality of functions F. The processing circuitry 23 may include dedicated processing circuitry corresponding to individual functions F. FIG.

Next, with reference to the flowchart shown in FIG. 11, the operation of the control device 300 will be described, focusing on the operation in the failure detection mode. That is, the processing shown in FIG. 11 is started at the first timing or the second timing.

When the lighting instruction signal S1 indicates lighting of two or more segments SG (step ST1 "YES"), the shift processing unit 12 starts shift processing (step ST2). As a result, the two or more segments SG sequentially start lighting as described with reference to FIGS. At this time, the processing of steps ST3 to ST5 below is executed, and the processing of step ST6 below is executed as appropriate.

That is, for the first segment SG among the two or more segments SG, the voltage estimation unit 11 calculates the voltage estimation value V2 (step ST3), and the voltage detection unit 13 calculates the voltage detection value V3. (Step ST4), the failure detection unit 14 determines whether or not there is a failure (step ST5). If it is determined that there is a failure (step ST5 "NO"), failure segment information is stored (step ST6).

By looping these processes (step ST7 "NO"), the voltage estimation process, the voltage detection process, and the failure detection process are executed for all the segments SG among the two or more segments SG.

When failure detection processing for all segments SG is completed (step ST7 "YES"), if failure segment information indicating at least one segment SG is stored (step ST8 "YES"), control device 300 sends a failure notification signal S4 to the ECU 400 (step ST9). Otherwise ("NO" in step ST8), control device 300 shifts from the failure detection mode to the normal lighting mode (step ST10).

If the lighting instruction signal S1 indicates lighting of only one segment SG (step ST1 "NO"), the shift process is unnecessary. Therefore, the process of step ST2 is skipped. This causes the one segment SG to start lighting. The voltage estimation process (step ST3), the current estimation process (step ST4) and the failure detection process (step ST5) are executed only once without looping.

Next, the effects of using the control device 300 will be described.

A conventional control device uses a plurality of voltage detectors corresponding to a plurality of segments when calculating voltage detection values corresponding to individual segments. P_1, P_2, and P_3 in FIG. 1 indicate examples of positions corresponding to positions where a plurality of voltage detectors are provided. There is a problem that the circuit scale of the lighting device becomes large due to the provision of the plurality of voltage detectors.

On the other hand, by performing the shift process, the voltage detection unit 13 can use one voltage detector 7 to calculate the voltage detection value V3 corresponding to each segment SG. That is, by using control device 300, the number of voltage detectors 7 in lighting device 200 can be reduced. As a result, the circuit scale of lighting device 200 can be reduced.

Next, a modification of the control device 300 will be described with reference to FIG.

Normally, the voltage characteristic of each segment SG has current dependency. Therefore, as shown in FIG. 12, in the lighting device 200, the current flowing through each segment SG is detected, and a value indicating the detected current (hereinafter referred to as "current detection value") I is sent to the control device 300. It may be input. The voltage estimator 11 may use the input detected current value I to calculate the estimated voltage value V2 based on characteristic information including the current-voltage characteristic of each segment SG. As a result, the estimated voltage value V2 can be calculated with higher accuracy. As a result, the presence or absence of a failure in each segment SG can be determined with higher accuracy.

Moreover, the voltage characteristic of each segment SG usually has temperature dependence. Therefore, as shown in FIG. 12, the temperature of the headlamp 100 is detected by the temperature detector 8, and a value indicating the detected temperature (hereinafter referred to as "temperature detection value") T is input to the controller 300. It can be anything. The temperature detector 8 is composed of, for example, a thermistor. The voltage estimating section 11 may use the input temperature detection value T to calculate the voltage estimation value V2 based on characteristic information including the temperature-voltage characteristic of each segment SG. As a result, the estimated voltage value V2 can be calculated with higher accuracy. As a result, the presence or absence of a failure in each segment SG can be determined with higher accuracy.

As described above, the control device 300 according to Embodiment 1 is a control device 300 for the headlamp 100 having the LED group 1 including a plurality of segments SG, and the estimated voltage value corresponding to each segment SG A voltage estimating unit 11 that calculates V2, a shift processing unit 12 that performs shift processing for shifting the current supply timing to the LED group 1 by the power supply circuit 3 by a shift amount δ that differs for each segment SG, and a shift processing unit 12 that performs shift processing. , a voltage detection unit 13 that sequentially calculates a voltage detection value V3 corresponding to each segment SG using a voltage detector 7 that detects the output voltage V1 of the power supply circuit 3; and a failure detection unit 14 that performs failure detection processing for determining the presence or absence of a failure in each segment SG by comparing with the value V2. This makes it possible to reduce the number of voltage detectors 7 in the lighting device 200 when detecting a failure in each segment SG. As a result, the circuit scale of the lighting device 200 can be reduced.

Further, the shift processing is realized by shifting the control period ΔT corresponding to each segment SG by a different shift amount δ for each segment SG. As a result, shift processing can be realized without lowering the duty ratio DR. As a result, for example, the shift process can be realized while maintaining the duty ratio DR corresponding to all segments SG at 100%.

Further, the shift process is realized by decreasing the duty ratio DR corresponding to each segment SG by a different decrease amount δ for each segment SG. At this time, each decrease amount δ is set to a sufficiently small value. As a result, the shift processing can be realized without making a human perceive a decrease in brightness due to a decrease in the duty ratio DR.

Further, when the headlamp 100 starts lighting, shift processing and failure detection processing are executed. Thereby, failures in individual segments SG can be detected at the first timing.

Also, when the content of the lighting instruction for the headlamp 100 changes, the shift process and the failure detection process are executed. As a result, a failure in each segment SG can be detected at the second timing.

Also, the voltage estimator 11 calculates an estimated voltage value V2 using the detected current value I corresponding to each segment. Thereby, the voltage estimated value V2 can be calculated with high accuracy. As a result, it is possible to accurately determine whether or not there is a failure in each segment SG.

Also, the voltage estimator 11 uses the temperature detection value T to calculate an estimated voltage value V2. Thereby, the voltage estimated value V2 can be calculated with high accuracy. As a result, it is possible to accurately determine whether or not there is a failure in each segment SG.

Embodiment 2.
Timings at which shift processing, failure detection processing, and the like are executed are not limited to the first timing and the second timing. In Embodiment 2, a modification of the control device 300, in which shift processing, failure detection processing, and the like are executed at different timings, will be described.

That is, the shift processing, the failure detection processing, and the like are executed at at least one of the first timing and the second timing, and the following timing (hereinafter referred to as "third timing"): ) may be executed. In other words, the shift process, the failure detection process, and the like may be executed at least one of the first timing, the second timing, and the third timing.

The third timing is the timing at which the output voltage V1 detected by the voltage detector 7 changes even though the content of the lighting instruction for the headlamp 100 by the ECU 400 (that is, the content of the lighting instruction signal S1) has not changed. is. The control device 300 has a function of shifting from the normal lighting mode to the failure detection mode at a third timing. As a result, shift processing, failure detection processing, and the like are executed.

Here, specific examples of the voltage estimation process, the shift process, the voltage detection process, and the failure detection process at the third timing will be described with reference to FIGS. 13 to 16. FIG. It is assumed that the lighting instruction signal S1 after time t0 instructs lighting of all the segments SG_1, SG_2, and SG_3.

<Fifth specific example (see FIG. 13)>
Time t0 corresponds to the first timing or the second timing. At the first timing or the second timing, voltage estimation processing, shift processing, voltage detection processing, and failure detection processing similar to those described with reference to FIG. 4 in the first embodiment are executed. It is determined by the failure detection process that there is no failure in any of the segments SG, and the control device 300 shifts from the failure detection mode to the normal lighting mode. Thereafter, control device 300 monitors output voltage V1 detected by voltage detector 7 .

After that, at time t4, it is assumed that the output voltage V1 has decreased due to the failure of the segment SG_3. On the other hand, at time t5, it is assumed that the control device 300 shifts from the normal lighting mode to the failure detection mode. As a result, the voltage estimation process, the shift process, the voltage detection process, and the failure detection process are executed at the third timing.

That is, the voltage estimation unit 11 calculates an estimated voltage value V2_1 corresponding to the segment SG_1, an estimated voltage value V2_2 corresponding to the segment SG_2, and an estimated voltage value V2_3 corresponding to the segment SG_3 based on the characteristic information.

At time t5, shift processing is started. That is, the shift processing unit 12 executes processing to shift the control period ΔT_1 corresponding to the segment SG_1 by the shift amount δ_1 (δ_1=0). Further, the shift processing unit 12 executes processing to shift the control period ΔT_2 corresponding to the segment SG_2 by the shift amount δ_2 (δ_2>δ_1). Further, the shift processing unit 12 executes processing to shift the control period ΔT_3 corresponding to the segment SG_3 by the shift amount δ_3 (δ_3>δ_2).

At time t6, the switch circuit 5_1 is in the off state, and the switch circuits 5_2 and 5_3 are in the on state. Therefore, the voltage detection unit 13 uses the output voltage V1_1 detected by the voltage detector 7 at time t6 to calculate the voltage detection value V3_1 corresponding to the segment SG_1. The voltage detection value V3_1 is calculated by the above equation (1).

At time t7, switch circuits 5_1 and 5_2 are off, and switch circuit 5_3 is on. Therefore, the voltage detection unit 13 uses the output voltage V1_1 detected by the voltage detector 7 at the time t6 and the output voltage V1_2 detected by the voltage detector 7 at the time t7 to detect the segment SG_2. A voltage detection value V3_2 is calculated. The voltage detection value V3_2 is calculated by the above equation (2).

At time t8, switch circuits 5_1, 5_2, and 5_3 are off. Therefore, the voltage detection unit 13 uses the output voltage V1_2 detected by the voltage detector 7 at the time t7 and the output voltage V1_3 detected by the voltage detector 7 at the time t8 to detect the segment SG_3. A voltage detection value V3_3 is calculated. The voltage detection value V3_3 is calculated by the above equation (3).

In this manner, the voltage detection value V3_1, the voltage detection value V3_2, and the voltage detection value V3_3 are sequentially calculated.

Next, the failure detection unit 14 executes failure detection processing. In the failure detection process, it is determined that there is no failure in the segment SG_1 because the difference value ΔV_1 is within the reference range Vth. Moreover, since the difference value ΔV_2 is within the reference range Vth, it is determined that there is no failure in the segment SG_2. On the other hand, since the difference value ΔV_3 is outside the reference range Vth, it is determined that there is a failure in the segment SG_3.

Thus, it is determined whether there is a failure in each of the segments SG_1, SG_2, and SG_3.

<Sixth example (see FIG. 14)>
Time t0 corresponds to the first timing or the second timing. At the first timing or the second timing, voltage estimation processing, shift processing, voltage detection processing, and failure detection processing similar to those described with reference to FIG. 5 in the first embodiment are executed. It is determined by the failure detection process that there is no failure in any of the segments SG, and the control device 300 shifts from the failure detection mode to the normal lighting mode. Thereafter, control device 300 monitors output voltage V1 detected by voltage detector 7 .

After that, at time t4, it is assumed that the output voltage V1 has decreased due to the failure of the segment SG_3. On the other hand, at time t5, it is assumed that the control device 300 shifts from the normal lighting mode to the failure detection mode. As a result, the voltage estimation process, the shift process, the voltage detection process, and the failure detection process are executed at the third timing.

The voltage estimation process in the sixth specific example is the same as the voltage estimation process in the fifth specific example. Therefore, repetitive description is omitted.

At time t5, shift processing is started. That is, the shift processing unit 12 executes processing to temporarily decrease the duty ratio DR_1 by the decrease amount δ_1 (δ_1=0). Further, the shift processing unit 12 executes processing to temporarily decrease the duty ratio DR_2 by a decrease amount δ_2 (δ_2>δ_1). Further, the shift processing unit 12 executes a process of temporarily decreasing the duty ratio DR_3 by a decrease amount δ_3 (δ_3>δ_2).

As a result, the duty ratio DR_2 temporarily drops to a value (eg, 80%) lower than the set value (ie, 100%). Also, the duty ratio DR_3 temporarily decreases to a value (eg, 60%) lower than the set value (ie, 100%).

As a result, at time t6, the switch circuit 5_1 is in the OFF state, and the switch circuits 5_2 and 5_3 are in the ON state. At time t7, the switch circuits 5_1 and 5_2 are in the OFF state, and the switch circuit 5_3 is in the ON state. At time t8, the switch circuits 5_1, 5_2, and 5_3 are in the OFF state.

Therefore, the voltage detection unit 13 executes voltage detection processing similar to the voltage detection processing in the fifth specific example. Thereby, the voltage detection value V3_1, the voltage detection value V3_2, and the voltage detection value V3_3 are sequentially calculated.

The failure detection process in the sixth specific example is the same as the failure detection process in the fifth specific example. Therefore, repetitive description is omitted.

<Seventh example (see FIG. 15)>
Time t0 corresponds to the first timing or the second timing. At the first timing or the second timing, voltage estimation processing, shift processing, voltage detection processing, and failure detection processing similar to those described with reference to FIG. 6 in the first embodiment are executed. It is determined by the failure detection process that there is no failure in any of the segments SG, and the control device 300 shifts from the failure detection mode to the normal lighting mode. Thereafter, control device 300 monitors output voltage V1 detected by voltage detector 7 .

After that, at time t4, it is assumed that the output voltage V1 has decreased due to the failure of the segment SG_3. On the other hand, at time t5, it is assumed that the control device 300 shifts from the normal lighting mode to the failure detection mode. As a result, the voltage estimation process, the shift process, the voltage detection process, and the failure detection process are executed at the third timing.

The voltage estimation process in the seventh specific example is the same as the voltage estimation process in the fifth specific example. Therefore, repetitive description is omitted.

At time t5, shift processing is started. That is, the shift processing unit 12 executes processing to shift the control period ΔT_1 by the shift amount δ_1 (δ_1=0). Further, the shift processing unit 12 executes processing to shift the control period ΔT_2 by a shift amount δ_2 (δ_2>δ_1). Further, the shift processing unit 12 executes processing to shift the control period ΔT_3 by a shift amount δ_3 (δ_3>δ_2).

As a result, at time t6, the switch circuit 5_1 is in the OFF state, and the switch circuits 5_2 and 5_3 are in the ON state. At time t7, the switch circuits 5_1 and 5_2 are in the OFF state, and the switch circuit 5_3 is in the ON state. At time t8, the switch circuits 5_1, 5_2, and 5_3 are in the OFF state.

Therefore, the voltage detection unit 13 executes voltage detection processing similar to the voltage detection processing in the fifth specific example. Thereby, the voltage detection value V3_1, the voltage detection value V3_2, and the voltage detection value V3_3 are sequentially calculated.

The fault detection process in the seventh specific example is the same as the fault detection process in the fifth specific example. Therefore, repetitive description is omitted.

<Eighth example (see FIG. 16)>
Time t0 corresponds to the first timing or the second timing. At the first timing or the second timing, voltage estimation processing, shift processing, voltage detection processing, and failure detection processing similar to those described with reference to FIG. 7 in the first embodiment are executed. It is determined by the failure detection process that there is no failure in any of the segments SG, and the control device 300 shifts from the failure detection mode to the normal lighting mode. Thereafter, control device 300 monitors output voltage V1 detected by voltage detector 7 .

After that, at time t4, it is assumed that the output voltage V1 has decreased due to the failure of the segment SG_3. On the other hand, at time t5, it is assumed that the control device 300 shifts from the normal lighting mode to the failure detection mode. As a result, the voltage estimation process, the shift process, the voltage detection process, and the failure detection process are executed at the third timing.

The voltage estimation process in the eighth specific example is the same as the voltage estimation process in the fifth specific example. Therefore, repetitive description is omitted.

At time t5, shift processing is started. That is, the shift processing unit 12 executes processing to temporarily decrease the duty ratio DR_1 by the decrease amount δ_1 (δ_1=0). Further, the shift processing unit 12 executes a process of temporarily decreasing the duty ratio DR_2 by a decrease amount δ_2 (δ_2>δ_1). Further, the shift processing unit 12 executes a process of temporarily decreasing the duty ratio DR_3 by a decrease amount δ_3 (δ_3>δ_2).

As a result, the duty ratio DR_2 temporarily drops to a value (eg, 50%) lower than the set value (ie, 70%). Also, the duty ratio DR_3 temporarily decreases to a value (eg, 20%) lower than the set value (ie, 60%).

As a result, at time t6, the switch circuit 5_1 is in the OFF state, and the switch circuits 5_2 and 5_3 are in the ON state. At time t7, the switch circuits 5_1 and 5_2 are in the OFF state, and the switch circuit 5_3 is in the ON state. At time t8, the switch circuits 5_1, 5_2, and 5_3 are in the OFF state.

Therefore, the voltage detection unit 13 executes voltage detection processing similar to the voltage detection processing in the fifth specific example. Thereby, the voltage detection value V3_1, the voltage detection value V3_2, and the voltage detection value V3_3 are sequentially calculated.

The fault detection process in the eighth specific example is the same as the fault detection process in the fifth specific example. Therefore, repetitive description is omitted.

In the sixth specific example and the eighth specific example, by executing the shift process at the third timing, the non-failed segments SG_1 and SG_2 among the segments SG_1, SG_2 and SG_3 to be lit are turned on. Some segments SG_2 are temporarily turned off. As a result, the brightness of the headlamp 100 is temporarily lowered. On the other hand, as described in the first embodiment, each of the shift amounts δ_1, δ_2, δ_3 is set to a sufficiently small value. This makes it possible to avoid such a decrease in brightness being perceived by humans.

Next, with reference to the flowchart shown in FIG. 17, the operation of the control device 300 will be described with a focus on the operation in the normal lighting mode. That is, the process shown in FIG. 17 is started when control device 300 shifts from the failure detection mode to the normal lighting mode.

First, control device 300 starts monitoring output voltage V1 detected by voltage detector 7 (step ST21). Further, the control device 300 starts lighting control according to the content of the lighting instruction from the ECU 400 (step ST22).

When the content of the lighting instruction has changed ("YES" in step ST23), the process of control device 300 returns to step ST22. When the output voltage V1 changes (step ST24 "YES") even though the content of the lighting instruction has not changed (step ST23 "NO"), the control device 300 shifts from the normal lighting mode to the failure detection mode. (step ST25). Thereby, the processing shown in FIG. 11 is started.

As described above, in the control device 300 according to the second embodiment, when the output voltage V1 of the power supply circuit 3 changes in a case where the content of the lighting instruction to the headlight 100 does not change, the shift processing and failure Detection processing is performed. Thereby, failures in individual segments SG can be detected at the third timing.

Also, the corresponding segment SG is temporarily turned off by executing the shift process. At this time, since each shift amount δ is set to a sufficiently small value, it is possible to avoid a decrease in brightness of the headlamp 100 from being perceived by humans.

In addition, within the scope of the disclosure of the present application, it is possible to freely combine each embodiment, modify any component of each embodiment, or omit any component in each embodiment. .

A control device according to the present disclosure can be used for a headlamp.

1 LED group 2 LED 3 power supply circuit 4 switch circuit group 5 switch circuit 6 drive circuit 7 voltage detector 8 temperature detector 11 voltage estimation unit 12 shift processing unit 13 voltage detection unit 14 Failure detection unit 21 Processor 22 Memory 23 Processing circuit 100 Headlight 200 Lighting device 300 Control device 400 ECU.

Claims (8)

A control device for a headlamp having an LED group including a plurality of segments, comprising:
a voltage estimator that calculates a voltage estimate corresponding to each segment;
a shift processing unit that performs shift processing for shifting the current supply timing to the LED group by the power supply circuit by a shift amount that differs for each segment;
a voltage detection unit that sequentially calculates voltage detection values corresponding to the individual segments using a voltage detector that detects the output voltage of the power supply circuit in accordance with the shift processing;
a failure detection unit that performs failure detection processing for determining whether or not there is a failure in each of the segments by comparing each of the detected voltage values with the corresponding estimated voltage value;
The control device, wherein the shift processing and the failure detection processing are executed when the headlamp starts lighting. A control device for a headlamp having an LED group including a plurality of segments, comprising:
a voltage estimator that calculates a voltage estimate corresponding to each segment;
a shift processing unit that performs shift processing for shifting the current supply timing to the LED group by the power supply circuit by a shift amount that differs for each of the segments;
a voltage detection unit that sequentially calculates voltage detection values corresponding to the individual segments using a voltage detector that detects the output voltage of the power supply circuit in accordance with the shift processing;
a failure detection unit that performs a failure detection process for determining whether or not there is a failure in each of the segments by comparing each of the detected voltage values with the corresponding estimated voltage value;
The control device, wherein the shift processing and the failure detection processing are executed when the content of the lighting instruction for the headlamp is changed. A control device for a headlamp having an LED group including a plurality of segments, comprising:
a voltage estimator that calculates a voltage estimate corresponding to each segment;
a shift processing unit that performs shift processing for shifting the current supply timing to the LED group by the power supply circuit by a shift amount that differs for each of the segments;
a voltage detection unit that sequentially calculates voltage detection values corresponding to the individual segments using a voltage detector that detects the output voltage of the power supply circuit in accordance with the shift processing;
a failure detection unit that performs a failure detection process for determining whether or not there is a failure in each of the segments by comparing each of the detected voltage values with the corresponding estimated voltage value;
The control device according to claim 1, wherein the shift processing and the failure detection processing are executed when the output voltage of the power supply circuit changes when the content of the lighting instruction for the headlamp has not changed. 4. The control device according to claim 3 , wherein the execution of the shift processing temporarily turns off the corresponding segment. A control device for a headlamp having an LED group including a plurality of segments, comprising:
a voltage estimator that calculates a voltage estimate corresponding to each segment;
a shift processing unit that performs shift processing for shifting the current supply timing to the LED group by the power supply circuit by a shift amount that differs for each segment;
a voltage detection unit that sequentially calculates voltage detection values corresponding to the individual segments using a voltage detector that detects the output voltage of the power supply circuit in accordance with the shift processing;
a failure detection unit that performs a failure detection process for determining whether or not there is a failure in each of the segments by comparing each of the detected voltage values with the corresponding estimated voltage value;
The control device, wherein the voltage estimator calculates the voltage estimated value using current detection values corresponding to the individual segments. The shift processing is realized by shifting the control period corresponding to each of the segments by a different shift amount for each segment . 6. A control device according to any one of claims 3 and 5 . The shift processing is realized by lowering the duty ratio corresponding to each of the segments by a different reduction amount for each segment . A control device according to any one of claims 3 and 5 . The control device according to any one of claims 1, 2, 3 and 5, wherein the voltage estimator calculates the voltage estimation value using a temperature detection value. .

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