WO2023106199A1 - Lighting circuit and vehicle lamp - Google Patents

Lighting circuit and vehicle lamp Download PDF

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Publication number
WO2023106199A1
WO2023106199A1 PCT/JP2022/044360 JP2022044360W WO2023106199A1 WO 2023106199 A1 WO2023106199 A1 WO 2023106199A1 JP 2022044360 W JP2022044360 W JP 2022044360W WO 2023106199 A1 WO2023106199 A1 WO 2023106199A1
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WO
WIPO (PCT)
Prior art keywords
light source
lighting circuit
circuit
period
abnormality
Prior art date
Application number
PCT/JP2022/044360
Other languages
French (fr)
Japanese (ja)
Inventor
洋之輔 原
俊幸 土屋
Original Assignee
株式会社小糸製作所
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Publication date
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Publication of WO2023106199A1 publication Critical patent/WO2023106199A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
    • B60Q1/02—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to illuminate the way ahead or to illuminate other areas of way or environments
    • B60Q1/04—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to illuminate the way ahead or to illuminate other areas of way or environments the devices being headlights
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q11/00—Arrangement of monitoring devices for devices provided for in groups B60Q1/00 - B60Q9/00
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/395—Linear regulators
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/40—Details of LED load circuits
    • H05B45/44—Details of LED load circuits with an active control inside an LED matrix
    • H05B45/48—Details of LED load circuits with an active control inside an LED matrix having LEDs organised in strings and incorporating parallel shunting devices
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/10—Controlling the light source
    • H05B47/105—Controlling the light source in response to determined parameters
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/10—Controlling the light source
    • H05B47/16—Controlling the light source by timing means
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/10—Controlling the light source
    • H05B47/165—Controlling the light source following a pre-assigned programmed sequence; Logic control [LC]
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/20—Responsive to malfunctions or to light source life; for protection
    • H05B47/23—Responsive to malfunctions or to light source life; for protection of two or more light sources connected in series

Definitions

  • the present invention relates to a lighting circuit and a vehicle lamp.
  • Patent Document 1 discloses a lighting circuit that controls the lighting of two light sources connected in series and that can detect an abnormality in the two light sources.
  • voltage detection circuits are provided at two locations (on the upstream side of each light source) in the current path of the drive current, and based on the outputs of the two voltage dividing circuits, Abnormality of each light source is detected. Therefore, two voltage dividing circuits are required, and two analog-to-digital conversion circuits (A/D conversion circuits) for converting the outputs of the voltage dividing circuits into digital signals are also required.
  • An object of the present invention is to provide a lighting circuit capable of detecting an abnormality with a simpler configuration.
  • a main aspect of the present invention for solving the aforementioned problems is a lighting circuit applied to a lamp including a first light source and a second light source connected in series with the first light source, the lighting circuit comprising: a first switch provided, a second switch provided in parallel with the second light source, a drive circuit for supplying drive current to the first and second light sources, and on/off control of the first and second switches and a control circuit for turning on or off the first and second light sources respectively, wherein the control circuit intermittently turns on one of the first and second light sources, a lighting circuit that detects an abnormality of the other light source based on the output voltage of the driving circuit during a first period in which the one light source is turned off and the other light source of the first and second light sources is turned on; be.
  • FIG. 1 is a block diagram of a vehicle lamp 1 using a lighting circuit 40 of this embodiment
  • FIG. 3 is a diagram showing an example of functional blocks implemented by a microcomputer 45
  • FIG. 4A and 4B are diagrams for explaining an abnormality detection operation by the lighting circuit 40 of the present embodiment
  • FIG. 10 is an explanatory diagram of abnormality determination; This is for explaining a modification of the abnormality detection operation by the lighting circuit 40 .
  • FIG. 1 is a diagram showing an example of the configuration of a vehicle lamp 1 using a lighting circuit 40 of this embodiment.
  • the vehicle lamp 1 is a lamp that lights the first light source 10 and the second light source 20 based on the voltage Vbat of the vehicle battery 2 .
  • the vehicle lamp 1 includes a first light source 10 , a second light source 20 and a lighting circuit 40 .
  • the first light source 10 is, for example, a low beam light source, and is connected between a terminal E and a terminal F (described later) of the lighting circuit 40 .
  • the low beam is used to illuminate the vicinity of the vehicle, and is mainly used when driving in urban areas.
  • the first light source 10 has at least one light emitting element 11 .
  • a light emitting diode LED
  • it is not limited to LEDs, and may be other semiconductor light emitting devices such as laser diodes (LD) and organic EL devices.
  • LD laser diodes
  • organic EL devices The same element (LED) as the light emitting element 11 is also used for the light emitting element 21 of the second light source 20 to be described later.
  • the number of light emitting elements 11 of the first light source 10 is one for the sake of simplification. It is assumed that A voltage (forward voltage) generated when the first light source 10 is turned on is voltage VF1.
  • the second light source 20 is, for example, a high beam light source, and is connected between a terminal G and a terminal H (described later) of the lighting circuit 40 .
  • the high beam illuminates a wide and distant area in front of the vehicle, and is mainly used when traveling at high speed on roads with few oncoming or preceding vehicles.
  • the terminal F and the terminal G are connected in the lighting circuit 40 , so the second light source 20 is connected in series with the first light source 10 .
  • the second light source 20 has at least one light emitting element 21 .
  • the number of the light emitting elements 21 of the second light source 20 is one for the sake of simplification. It is assumed that A voltage (forward voltage) generated when the second light source 20 is turned on is voltage VF2.
  • the values of voltage VF1 and voltage VF2 are different.
  • the values of the voltage VF1 and the voltage VF2 differ greatly, it is possible to reliably detect an abnormality in each light source. It should be noted that abnormality can be similarly detected even when voltage VF1 and voltage VF2 are the same (the number of light emitting elements 11 and 21 is the same).
  • the lighting circuit 40 is a circuit for lighting the first light source 10 and the second light source 20 according to instructions from a control device (not shown; hereinafter also referred to as a vehicle-side ECU) provided on the vehicle side.
  • the lighting circuit 40 of this embodiment includes a drive circuit 41, a voltage dividing circuit 42, a memory circuit 44, a microcomputer 45, switches SW1 and SW2, and terminals A to H.
  • the lighting circuit 40 is a module in which the circuits and terminals described above are attached to a substrate.
  • a terminal A is a terminal connected to the positive electrode of the battery 2 via the lighting switch SW0, and a power supply voltage (voltage Vbat) is applied from the battery 2 when the lighting switch SW0 is turned on.
  • a terminal B is a terminal connected to the negative electrode of the battery 2, and a ground level voltage is applied from the battery 2.
  • a terminal C is a terminal to which a control signal S1 is input from the vehicle-side ECU.
  • the control signal S1 is a signal that instructs to turn on/off the first light source 10 and the second light source 20 .
  • a terminal D is a terminal that outputs a detection signal S2 to the vehicle-side ECU.
  • the detection signal S2 is a signal indicating that at least one of the first light source 10 and the second light source 20 has detected an abnormality.
  • Terminals E and F are terminals for connecting the first light source 10 . Also, the terminal E is applied with the output voltage Vout of the drive circuit 41 .
  • Terminals G and H are terminals for connecting the second light source 20 .
  • the terminal G is connected to the terminal F, and the terminal H is connected to the terminal B. As shown in FIG.
  • the switch SW1 is a switch provided between the terminal E and the terminal F (in other words, parallel to the first light source 10) and corresponds to the "first switch".
  • the switch SW1 When the switch SW1 is on (conductive), a path is formed in which current is supplied to the second light source 20 bypassing the first light source 10 . As a result, no current is supplied to the first light source 10, so that the first light source 10 is turned off without lighting.
  • the switch SW1 is off (non-conducting)
  • current is supplied to the first light source 10, and the first light source 10 is turned on.
  • the switch SW2 is a switch provided between the terminal G and the terminal H (in other words, parallel to the second light source 20) and corresponds to a "second switch".
  • a path bypassing the second light source 20 is formed.
  • no current is supplied to the second light source 20, so that the second light source 20 is turned off without lighting.
  • the switch SW2 is off, current is supplied to the second light source 20 and the second light source 20 is turned on.
  • the drive circuit 41 is a circuit (constant current circuit) that supplies a drive current for lighting the first light source 10 and the second light source 20 based on the voltage Vbat of the battery 2. is provided.
  • the drive circuit 41 is composed of, for example, a step-down switching regulator (DC-DC converter). Note that the drive circuit 41 is not limited to a step-down type, and may be a step-up type. Further, the drive circuit 41 is not limited to a switching regulator, and may be a linear regulator, for example.
  • the voltage dividing circuit 42 is a circuit that divides the voltage of the node N between the driving circuit 41 and the terminal E (the output voltage Vout of the driving circuit 41).
  • the voltage dividing circuit 42 includes, for example, two resistors connected in series between the node N and ground (GND). The voltage of node N (output voltage Vout) is divided by two resistors.
  • the storage circuit 44 is a circuit that stores programs and various data for executing control in the microcomputer 45, and is composed of a semiconductor memory, for example.
  • the storage circuit 44 also stores data regarding the voltage VF1 of the first light source 10, data regarding the voltage VF2 of the second light source 20, and the like.
  • the storage circuit 44 stores the values of the voltage VF1 and the voltage VF2 as normal ranges having upper and lower limits.
  • the normal range corresponding to voltage VF1 is defined as range R1
  • the normal range corresponding to voltage VF2 is defined as range R2.
  • the range R1 corresponds to the "first range”
  • the range R2 corresponds to the "second range”.
  • the ranges R1 and R2 are converted into values (ranges) corresponding to the voltage dividing ratio (resistance ratio) of the voltage dividing circuit 42 and stored.
  • the storage circuit 44 is provided separately from the microcomputer 45.
  • the present invention is not limited to this, and the storage circuit 44 and the microcomputer 45 are integrated. may
  • the microcomputer 45 is a circuit that controls the operation of the vehicle lamp 1 and corresponds to a "control circuit".
  • a sampling mode is provided. In the sampling mode, the microcomputer 45 turns on and off the switches SW1 and SW2 at a predetermined cycle T (described later) to intermittently light the first light source 10 and the second light source 20, respectively.
  • FIG. 2 is a diagram showing an example of functional blocks implemented in the microcomputer 45.
  • the microcomputer 45 is implemented by elements and circuits such as a computer CPU and memory as hardware configuration, and is implemented by computer programs etc. as software configuration. is shown as a function block to be implemented.
  • the microcomputer 45 of this embodiment includes a control section 451 , a detection section 452 and a transmission section 453 .
  • the control unit 451 turns on and off the switches SW1 and SW2 based on the control signal S1 input from the vehicle-side ECU (not shown). In other words, the controller 451 turns on or off the first light source 10 by controlling the on/off of the switch SW1. Further, the control unit 451 turns on or off the second light source 20 by controlling the on/off of the switch SW2.
  • the detection unit 452 detects whether or not the first light source 10 and the second light source 20 are abnormal based on the output of the voltage dividing circuit 42 (divided voltage of the output voltage Vout).
  • the input port of the microcomputer 45 connected to the voltage dividing circuit 42 is composed of an A/D conversion input port having an analog-to-digital conversion function, and the output of the voltage dividing circuit 42 is It is converted into a digital signal (digital data) at the input port of the microcomputer 45 .
  • an A/D conversion circuit may be provided in the voltage dividing circuit 42 to input a digital signal.
  • the detection unit 452 compares the data acquired from the voltage dividing circuit 42 with the data stored in the storage circuit 44 .
  • the values in the ranges (ranges R1 and R2) stored in the storage circuit 44 are converted according to the voltage dividing ratio of the voltage dividing circuit 42.
  • FIG. Therefore, comparing the data in the voltage dividing circuit 42 and the data in the storage circuit 44 in the detection unit 452 means comparing the output voltage Vout of the driving circuit 41 with the actual normal ranges (ranges R1 and R2). are equivalent.
  • the detection unit 452 detects an abnormality of the first light source 10 based on whether the output voltage Vout is included in the range R1. Further, an abnormality of the second light source 20 is detected based on whether the output voltage Vout is included in the range R2. The timing (period) for detecting an abnormality in each light source will be described later.
  • the transmission unit 453 transmits a detection signal S2 indicating that fact to the vehicle-side ECU (not shown).
  • FIG. 3 is a diagram for explaining the operation of abnormality detection by the lighting circuit 40 of the present embodiment.
  • "high level” indicates an ON state (conducting state)
  • "low level” indicates an OFF state (non-conducting state). showing.
  • the cycle T shown in the figure is a short period of, for example, 5 ms, and in this cycle T, periods (periods TA, TC) are provided for turning off the first light source 10 and the second light source 20, respectively. That is, in the period T, the first light source 10 and the second light source 20 are controlled to be lit intermittently. Before time t0 in FIG. 3, both the first light source 10 and the second light source 20 are turned on, and the sampling mode is entered at time t0.
  • the control section 451 of the microcomputer 45 turns off the switch SW1 and turns on the switch SW2. That is, the first light source 10 is turned on and the second light source 20 is turned off. Therefore, during the period TA, if the first light source 10 is normal, the voltage of the node N becomes VF1.
  • a detection unit 452 of the microcomputer 45 compares the output of the voltage dividing circuit 42 and the data of the storage circuit 44, and detects whether the output voltage Vout of the driving circuit 41 is included in the range R1 corresponding to the voltage VF1.
  • the control section 451 of the microcomputer 45 turns off both the switches SW1 and SW2. That is, both the first light source 10 and the second light source 20 are turned on. Therefore, if both the first light source 10 and the second light source 20 are normal during the period TB, the voltage of the node N becomes (VF1+VF2). In this embodiment, abnormality detection of each light source is not performed during this period TB. The reason for this will be described later.
  • the control section 451 of the microcomputer 45 turns on the switch SW1 and turns off the switch SW2. That is, the first light source 10 is turned off and the second light source 20 is turned on. Therefore, during the period TC, if the second light source 20 is normal, the voltage of the node N becomes VF2.
  • a detection unit 452 of the microcomputer 45 compares the output of the voltage dividing circuit 42 and the data of the storage circuit 44, and detects whether the output voltage Vout of the driving circuit 41 is included in the range R2 corresponding to the voltage VF2.
  • the same processing is repeated with a period T.
  • the period T corresponds to a "predetermined period”
  • one of the period TA and the period TC corresponds to "one period”
  • the other corresponds to the "second period”.
  • the period TB corresponds to the "third period”.
  • FIG. 4 is an explanatory diagram of abnormality determination.
  • the figure shows a range R1 of the voltage VF1 when the first light source 10 is normally lit and a range R2 of the voltage VF2 when the second light source 20 is normally lit.
  • the range R1 and the range R2 are different.
  • the detection unit 452 of the microcomputer 45 can grasp the light source (either the first light source 10 or the second light source 20) for which abnormality detection is performed, depending on the period (period TA, period TC) during which abnormality is detected. If the output voltage Vout is within the normal range of the light source, the detection unit 452 determines that it is "normal”, and if it is not within the normal range, it determines that it is "abnormal".
  • the detection unit 452 detects whether the output voltage Vout (the voltage at the node N) is within the range R1. Specifically, when the output voltage Vout is the voltage indicated by the dashed-dotted line in the figure, it is included in the range R1, so the detection unit 452 determines that the first light source 10 is normal. When the output voltage Vout is the voltage indicated by the dashed line in the figure, it is not included in the range R1, so the detection unit 452 determines that the first light source 10 is abnormal.
  • the detection unit 452 detects whether the output voltage Vout (the voltage at the node N) is included in the range R2. Specifically, when the output voltage Vout is the voltage indicated by the dashed line in the figure, it is included in the range R2, so the detection unit 452 determines that the second light source 20 is normal. When the output voltage Vout is the voltage indicated by the dashed-dotted line in the drawing, the detection unit 452 determines that the second light source 20 is abnormal because it is not included in the range R2.
  • the detection unit 452 does not detect an abnormality during the period TB in which both the first light source 10 and the second light source 20 are turned on. This is because if the normal range of (VF1+VF2) is set in the period TB and the abnormality is detected, there is a possibility that the abnormality cannot be detected correctly. For example, when VF2>VF1, if the light emitting element 11 of the first light source 10 is short-circuited, the output voltage Vout becomes VF2. The value of the voltage VF2 at this time may fall within the normal range of (VF1+VF2).
  • the output voltage Vout is higher than the upper limit of the normal range (for example, in the case of the MAX value), it can be determined that there is an abnormality due to open (disconnection) of the light emitting elements (light emitting elements 11 and 21). Also, when the output voltage Vout is lower than the lower limit of the normal range (for example, when it is zero), it can be determined that there is an abnormality due to a short circuit of the light emitting elements (light emitting elements 11 and 21). In this way, an open circuit and a short circuit can be detected separately.
  • the upper limit of the normal range for example, in the case of the MAX value
  • the transmission unit 453 transmits a detection signal S2 indicating the result to the vehicle-side ECU. .
  • the vehicle-side ECU When the vehicle-side ECU receives the detection signal S2, it notifies the driver or the like that an abnormality has occurred.
  • notification methods include visual notification such as light emission and display, auditory notification such as sound, and tactile notification such as vibration.
  • the lighting circuit 40 of the present embodiment uses only the voltage at one point (node N) in the current path of the driving current to detect the abnormality of the first light source 10 and the abnormality of the second light source 20 respectively. can be detected. That is, one voltage dividing circuit 42 and one A/D conversion circuit (in this embodiment, the A/D conversion input port of the microcomputer 45) are sufficient. Therefore, an abnormality of each light source can be detected with a simple configuration.
  • FIG. 5 is a diagram for explaining a modification of the abnormality detection operation by the lighting circuit 40.
  • the configuration of the vehicle lamp 1 (the first light source 10, the second light source 20, and the lighting circuit 40) is the same as in the above-described embodiment, and the same reference numerals are used.
  • each of the first light source 10 and the second light source 20 has a longer turn-off time (shorter turn-on time) than in the above-described embodiment.
  • the control unit 451 of the microcomputer 45 turns off the switch SW1 and turns on the switch SW2. That is, the first light source 10 is turned on and the second light source 20 is turned off.
  • the voltage of the node N becomes VF1.
  • the detection unit 452 of the microcomputer 45 compares the output of the voltage dividing circuit 42 and the data of the storage circuit 44 in the period TD to determine whether the output voltage Vout of the driving circuit 41 is included in the range R1 corresponding to the voltage VF1. to detect It should be noted that the abnormality may be detected during the period TE.
  • the control section 451 of the microcomputer 45 turns on both the switches SW1 and SW2. That is, both the first light source 10 and the second light source 20 are turned off. As a result, the voltage of the node N becomes the ground potential (earth). No abnormality is detected during this period TF.
  • the control section 451 of the microcomputer 45 turns on the switch SW1 and turns off the switch SW2. That is, the first light source 10 is turned off and the second light source 20 is turned on.
  • the voltage of the node N becomes VF2 if the second light source 20 is normal.
  • a detection unit 452 of the microcomputer 45 compares the output of the voltage dividing circuit 42 and the data of the storage circuit 44, and detects whether the output voltage Vout of the driving circuit 41 is included in the range R2 corresponding to the voltage VF2.
  • the same processing is repeated with a period T.
  • the first light source 10 and the second light source 20 are intermittently lit.
  • the lighting time of the first light source 10 and the second light source 20 is shorter (the lighting time is longer) than in the above-described embodiment (FIG. 3).
  • the period T corresponds to the "predetermined period”
  • one of the period TD and the period TG corresponds to the "first period”
  • the other for example, the period TG
  • the vehicle lamp 1 of the present embodiment has been described above.
  • the lighting circuit 40 of the vehicle lamp 1 supplies a drive current to the switch SW1 provided in parallel with the first light source 10, the switch SW2 provided in parallel with the second light source 20, and the first light source 10 and the second light source 20. and a microcomputer 45 for turning on or off the first light source 10 and the second light source 20 by controlling the on/off of the switches SW1 and SW2. Then, in a state in which one light source (for example, the second light source 20) is intermittently lit, the microcomputer 45 turns off the second light source 20 and turns on the first light source 10 during the period TA during which the drive circuit 41 is turned on. Abnormality of the first light source 10 is detected based on the output voltage Vout. This makes it possible to detect an abnormality in the first light source 10 with a simple configuration.
  • the microcomputer 45 turns off the first light source 10 and turns on the second light source 20 during the period TC. Abnormality of the second light source 20 is detected based on the output voltage Vout. This makes it possible to detect an abnormality in the second light source 20 with a simple configuration.
  • the microcomputer 45 repeats the ON/OFF control of the switches SW1 and SW2 in a cycle T so that the first light source 10 and the second light source 20 are intermittently lit. include. This makes it possible to detect an abnormality in the first light source 10 and the second light source 20 with a simple configuration.
  • the cycle T also includes a period TB during which both the first light source 10 and the second light source 20 are turned on. This makes it possible to brighten even when the light sources are intermittently turned on. By not detecting an abnormality in the first light source 10 and the second light source 20 during the period TB, erroneous detection can be suppressed.
  • the microcomputer 45 detects abnormality of the first light source 10 based on whether the output voltage Vout is included in the range R1 in the period TA, and the output voltage Vout is included in the range R2 in the period TC. Abnormality of the light source of the second light source 20 is detected based on whether or not the light source of the second light source 20 is detected. As a result, anomalies of the first light source 10 and the second light source 20 can be reliably detected.
  • the first light source 10 has at least one light emitting element 11 and the second light source 20 has at least one light emitting element 21 .
  • the lighting circuit 40 of this embodiment even if the number of the light emitting elements 11 of the first light source 10 and the number of the light emitting elements 21 of the second light source 20 are different, it is possible to reliably detect an abnormality in each light source. Therefore, it is more effective in this case.
  • the lighting circuit 40 of the present embodiment is suitable for a lamp used in a vehicle (vehicle lamp 1).
  • vehicle lamp 1 vehicle lamp 1
  • the present invention is not limited to this, and may be applied to lighting fixtures such as street lights, for example. Similar effects can be obtained in this case as well.
  • the first light source 10 is a low beam light source and the second light source 20 is a high beam light source, but the present invention is not limited to this.
  • the first light source 10 may be a high beam light source
  • the second light source 20 may be a low beam light source.
  • low beam and high beam may be a combination of other lamps (for example, DRL (Daytime Running Lamp), CLL (Clearance Lamp), turn signal lamp, etc.).
  • DRL Daytime Running Lamp
  • CLL Chiplearance Lamp
  • a DRL is a lamp that lights up during the day to notify pedestrians and drivers of oncoming vehicles of the presence of a vehicle in motion.
  • a CLL is a lamp mounted on the front of a vehicle to indicate the width of the vehicle and its presence.
  • a turn signal lamp is a lamp that blinks to notify drivers of vehicles ahead and behind when the vehicle turns, changes course, and the like.
  • the number is not limited to this, and may be three or more. Also in this case, by performing similar control, an abnormality of each light source can be detected.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Lighting Device Outwards From Vehicle And Optical Signal (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

The present invention provides a lighting circuit capable of detecting an abnormality using a simple configuration. The present invention provides a lighting circuit applied to a lamp comprising a first light source and a second light source connected in series to the first light source. The lighting circuit is provided with: a first switch provided in parallel with the first light source; a second switch provided in parallel with the second light source; a drive circuit for supplying a drive current to the first and second light sources; and a control circuit for lighting up or extinguishing the first and second light sources by on/off control of the first and second switches. In a state in which one of the first and second light sources is intermittently lit up, the control circuit detects an abnormality of the other light source on the basis of an output voltage of the drive circuit during a first time period in which the one light source is extinguished and the other of the first and second light sources is lit up.

Description

点灯回路、及び車両用灯具Lighting circuit and vehicle lamp
　本発明は、点灯回路、及び車両用灯具に関する。 The present invention relates to a lighting circuit and a vehicle lamp.
　灯具（例えば、車両用灯具）に適される点灯回路として、特許文献１には、直列接続された２つの光源の点灯を制御するとともに、２つの光源の異常を検出可能にしたものが開示されている。 As a lighting circuit suitable for a lamp (for example, a vehicle lamp), Patent Document 1 discloses a lighting circuit that controls the lighting of two light sources connected in series and that can detect an abnormality in the two light sources. there is
特開２０２０－８７８３０号公報Japanese Unexamined Patent Application Publication No. 2020-87830
　特許文献１の点灯回路では、駆動電流の電流経路の２箇所（各光源の上流側）に電圧検出用の回路（分圧回路）を設けており、２つの分圧回路の出力に基づいて、各光源の異常を検出している。このため、分圧回路が２つ必要であり、分圧回路の出力をデジタル信号に変換するアナログ－デジタル変換回路（Ａ／Ｄ変換回路）も２つ必要になる。 In the lighting circuit of Patent Document 1, voltage detection circuits (voltage dividing circuits) are provided at two locations (on the upstream side of each light source) in the current path of the drive current, and based on the outputs of the two voltage dividing circuits, Abnormality of each light source is detected. Therefore, two voltage dividing circuits are required, and two analog-to-digital conversion circuits (A/D conversion circuits) for converting the outputs of the voltage dividing circuits into digital signals are also required.
　本発明の目的は、より簡易な構成で、異常を検出可能な点灯回路を提供することにある。 An object of the present invention is to provide a lighting circuit capable of detecting an abnormality with a simpler configuration.
　前述した課題を解決する主たる本発明は、第１光源と、前記第１光源に直列接続された第２光源と、を備える灯具に適用される点灯回路であって、前記第１光源に並列に設けられる第１スイッチと、前記第２光源に並列に設けられる第２スイッチと、前記第１及び第２光源に駆動電流を供給する駆動回路と、前記第１及び第２スイッチのオンオフを制御することにより、前記第１及び第２光源をそれぞれ点灯又は消灯させる制御回路と、を備え、前記制御回路は、前記第１及び第２光源の一方の光源を間欠的に点灯させている状態において、前記一方の光源を消灯させ、前記第１及び第２光源の他方の光源を点灯させる第１期間に、前記駆動回路の出力電圧に基づいて、前記他方の光源の異常の検出を行う点灯回路である。 A main aspect of the present invention for solving the aforementioned problems is a lighting circuit applied to a lamp including a first light source and a second light source connected in series with the first light source, the lighting circuit comprising: a first switch provided, a second switch provided in parallel with the second light source, a drive circuit for supplying drive current to the first and second light sources, and on/off control of the first and second switches and a control circuit for turning on or off the first and second light sources respectively, wherein the control circuit intermittently turns on one of the first and second light sources, a lighting circuit that detects an abnormality of the other light source based on the output voltage of the driving circuit during a first period in which the one light source is turned off and the other light source of the first and second light sources is turned on; be.
　本発明によれば、簡易な構成で、異常を検出可能な点灯回路を提供することができる。 According to the present invention, it is possible to provide a lighting circuit capable of detecting an abnormality with a simple configuration.
本実施形態の点灯回路４０を用いた車両用灯具１のブロック図である。1 is a block diagram of a vehicle lamp 1 using a lighting circuit 40 of this embodiment; FIG. マイコン４５に実現される機能ブロックの一例を示す図である。3 is a diagram showing an example of functional blocks implemented by a microcomputer 45; FIG. 本実施形態の点灯回路４０による異常検出の動作を説明するための図である。4A and 4B are diagrams for explaining an abnormality detection operation by the lighting circuit 40 of the present embodiment; FIG. 異常の判定についての説明図である。FIG. 10 is an explanatory diagram of abnormality determination; 点灯回路４０による異常検出の動作の変形例を説明するためのである。This is for explaining a modification of the abnormality detection operation by the lighting circuit 40 .
　本明細書及び添付図面の記載により、少なくとも以下の事項が明らかとなる。 At least the following matters become clear from the description of this specification and the attached drawings.
＝＝＝＝＝実施形態＝＝＝＝＝
＜＜車両用灯具１の構成＞＞
　図１は、本実施形態の点灯回路４０を用いた車両用灯具１の構成の一例を示す図である。 =====Embodiment=====
<<Configuration of Vehicle Lamp 1>>
FIG. 1 is a diagram showing an example of the configuration of a vehicle lamp 1 using a lighting circuit 40 of this embodiment.
　車両用灯具１は、車両用のバッテリー２の電圧Ｖｂａｔに基づいて、第１光源１０及び第２光源２０を点灯させる灯具である。車両用灯具１は、第１光源１０、第２光源２０、及び点灯回路４０を含んで構成される。 The vehicle lamp 1 is a lamp that lights the first light source 10 and the second light source 20 based on the voltage Vbat of the vehicle battery 2 . The vehicle lamp 1 includes a first light source 10 , a second light source 20 and a lighting circuit 40 .
＜第１光源１０＞
　第１光源１０は、例えば、ロービーム用の光源であり、点灯回路４０の端子Ｅと端子Ｆ（後述）の間に接続されている。なお、ロービームは、自車の近傍を照明するものであり、対向車や先行車にグレアを与えないよう配光規定が定められており、主に市街地を走行する場合に用いられる。 <First light source 10>
The first light source 10 is, for example, a low beam light source, and is connected between a terminal E and a terminal F (described later) of the lighting circuit 40 . The low beam is used to illuminate the vicinity of the vehicle, and is mainly used when driving in urban areas.
　第１光源１０は、少なくとも１つの発光素子１１を有している。本実施形態では発光素子１１として発光ダイオード（ＬＥＤ）が用いられている。ただし、ＬＥＤには限られず、例えば、レーザダイオード（ＬＤ）や有機ＥＬ素子などの他の半導体発光素子でもよい。なお、後述する第２光源２０の発光素子２１についても発光素子１１と同じ素子（ＬＥＤ）が用いられている。 The first light source 10 has at least one light emitting element 11 . In this embodiment, a light emitting diode (LED) is used as the light emitting element 11 . However, it is not limited to LEDs, and may be other semiconductor light emitting devices such as laser diodes (LD) and organic EL devices. The same element (LED) as the light emitting element 11 is also used for the light emitting element 21 of the second light source 20 to be described later.
　また、図１では簡略化のため第１光源１０の発光素子１１の数を１つとしているが、本実施形態の第１光源１０には、発光素子１１が複数（例えば６個）直列接続されていていることとする。また、第１光源１０が点灯することにより発生する電圧（順方向電圧）を電圧ＶＦ１とする。 In FIG. 1, the number of light emitting elements 11 of the first light source 10 is one for the sake of simplification. It is assumed that A voltage (forward voltage) generated when the first light source 10 is turned on is voltage VF1.
＜第２光源２０＞
　第２光源２０は、例えば、ハイビーム用の光源であり、点灯回路４０の端子Ｇと端子Ｈ（後述）の間に接続されている。なお、ハイビームは、車両前方の広範囲および遠方を照明するものであり、主に対向車や先行車が少ない道路を高速走行する際に用いられる。後述するように、点灯回路４０において端子Ｆと端子Ｇは接続されているため、第２光源２０は、第１光源１０と直列接続されている。 <Second light source 20>
The second light source 20 is, for example, a high beam light source, and is connected between a terminal G and a terminal H (described later) of the lighting circuit 40 . The high beam illuminates a wide and distant area in front of the vehicle, and is mainly used when traveling at high speed on roads with few oncoming or preceding vehicles. As will be described later, the terminal F and the terminal G are connected in the lighting circuit 40 , so the second light source 20 is connected in series with the first light source 10 .
　また、第２光源２０は、少なくとも１つの発光素子２１を有している。図１では簡略化のため第２光源２０の発光素子２１の数を１つとしているが、本実施形態の第２光源２０には、発光素子２１が複数（例えば３個）直列接続されていることとする。また、第２光源２０が点灯することにより発生する電圧（順方向電圧）を電圧ＶＦ２とする。 Also, the second light source 20 has at least one light emitting element 21 . In FIG. 1, the number of the light emitting elements 21 of the second light source 20 is one for the sake of simplification. It is assumed that A voltage (forward voltage) generated when the second light source 20 is turned on is voltage VF2.
　第１光源１０の発光素子１１の数と、第２光源２０の発光素子２１の数が異なると、電圧ＶＦ１と電圧ＶＦ２の値が異なることになる。本実施形態の点灯回路４０では、電圧ＶＦ１と電圧ＶＦ２の値が大きく異なる場合でも、それぞれの光源について、確実に異常を検出することができる。なお、電圧ＶＦ１と電圧ＶＦ２が同じ（発光素子１１と発光素子２１の数が同じ）場合も、同様に異常を検出することができる。 If the number of light emitting elements 11 of the first light source 10 and the number of light emitting elements 21 of the second light source 20 are different, the values of voltage VF1 and voltage VF2 are different. In the lighting circuit 40 of the present embodiment, even if the values of the voltage VF1 and the voltage VF2 differ greatly, it is possible to reliably detect an abnormality in each light source. It should be noted that abnormality can be similarly detected even when voltage VF1 and voltage VF2 are the same (the number of light emitting elements 11 and 21 is the same).
＜点灯回路４０＞
　点灯回路４０は、車両側に設けられた制御装置（不図示：以下、車両側ＥＣＵともいう）の指示に従い、第１光源１０及び第２光源２０を点灯させる回路である。本実施形態の点灯回路４０は、駆動回路４１、分圧回路４２、記憶回路４４、マイコン４５、スイッチＳＷ１，ＳＷ２、及び端子Ａ～Ｈを備えている。なお、点灯回路４０は、上記の各回路及び各端子が、基板に取り付けられたモジュールである。 <Lighting circuit 40>
The lighting circuit 40 is a circuit for lighting the first light source 10 and the second light source 20 according to instructions from a control device (not shown; hereinafter also referred to as a vehicle-side ECU) provided on the vehicle side. The lighting circuit 40 of this embodiment includes a drive circuit 41, a voltage dividing circuit 42, a memory circuit 44, a microcomputer 45, switches SW1 and SW2, and terminals A to H. The lighting circuit 40 is a module in which the circuits and terminals described above are attached to a substrate.
　端子Ａは、点灯スイッチＳＷ０を介してバッテリー２の正極に接続される端子であり、点灯スイッチＳＷ０がオンされることにより、バッテリー２から電源電圧（電圧Ｖｂａｔ）が印加される。 A terminal A is a terminal connected to the positive electrode of the battery 2 via the lighting switch SW0, and a power supply voltage (voltage Vbat) is applied from the battery 2 when the lighting switch SW0 is turned on.
　端子Ｂは、バッテリー２の負極に接続される端子であり、バッテリー２から接地レベルの電圧が印加される。 A terminal B is a terminal connected to the negative electrode of the battery 2, and a ground level voltage is applied from the battery 2.
　端子Ｃは、車両側ＥＣＵから制御信号Ｓ１が入力される端子である。なお、制御信号Ｓ１は、第１光源１０及び第２光源２０の点灯、消灯を指示する信号である。 A terminal C is a terminal to which a control signal S1 is input from the vehicle-side ECU. Note that the control signal S1 is a signal that instructs to turn on/off the first light source 10 and the second light source 20 .
　端子Ｄは、車両側ＥＣＵに検出信号Ｓ２を出力する端子である。なお、検出信号Ｓ２は、第１光源１０及び第２光源２０の少なくとも一方に異常が検出されたことを示す信号である。 A terminal D is a terminal that outputs a detection signal S2 to the vehicle-side ECU. The detection signal S2 is a signal indicating that at least one of the first light source 10 and the second light source 20 has detected an abnormality.
　端子Ｅ及び端子Ｆは、第１光源１０を接続するための端子である。また、端子Ｅには駆動回路４１の出力電圧Ｖｏｕｔが印加される。 Terminals E and F are terminals for connecting the first light source 10 . Also, the terminal E is applied with the output voltage Vout of the drive circuit 41 .
　端子Ｇ及び端子Ｈは、第２光源２０を接続するための端子である。また、点灯回路４０内において、端子Ｇは端子Ｆと接続されており、端子Ｈは端子Ｂと接続されている。 Terminals G and H are terminals for connecting the second light source 20 . In the lighting circuit 40, the terminal G is connected to the terminal F, and the terminal H is connected to the terminal B. As shown in FIG.
　スイッチＳＷ１は、端子Ｅと端子Ｆの間に（換言すると、第１光源１０に並列に）設けられたスイッチであり、「第１スイッチ」に相当する。スイッチＳＷ１がオン（導通）の場合、第１光源１０を迂回して第２光源２０へ電流が供給される経路が形成される。この結果、第１光源１０に電流が供給されなくなるので、第１光源１０は点灯せず消灯状態になる。一方、スイッチＳＷ１がオフ（非導通）の場合、第１光源１０に電流が供給されて、第１光源１０は点灯状態になる。 The switch SW1 is a switch provided between the terminal E and the terminal F (in other words, parallel to the first light source 10) and corresponds to the "first switch". When the switch SW1 is on (conductive), a path is formed in which current is supplied to the second light source 20 bypassing the first light source 10 . As a result, no current is supplied to the first light source 10, so that the first light source 10 is turned off without lighting. On the other hand, when the switch SW1 is off (non-conducting), current is supplied to the first light source 10, and the first light source 10 is turned on.
　スイッチＳＷ２は、端子Ｇと端子Ｈの間に（換言すると、第２光源２０に並列に）設けられたスイッチであり、「第２スイッチ」に相当する。スイッチＳＷ２がオンの場合、第２光源２０を迂回する経路が形成される。この結果、第２光源２０には電流が供給されなくなるので、第２光源２０は点灯せず消灯状態になる。一方、スイッチＳＷ２がオフの場合、第２光源２０に電流が供給されて、第２光源２０は点灯状態になる。 The switch SW2 is a switch provided between the terminal G and the terminal H (in other words, parallel to the second light source 20) and corresponds to a "second switch". When the switch SW2 is on, a path bypassing the second light source 20 is formed. As a result, no current is supplied to the second light source 20, so that the second light source 20 is turned off without lighting. On the other hand, when the switch SW2 is off, current is supplied to the second light source 20 and the second light source 20 is turned on.
　駆動回路４１は、バッテリー２の電圧Ｖｂａｔに基づいて、第１光源１０及び第２光源２０を点灯させるための駆動電流を供給する回路（定電流回路）であり、端子Ａと端子Ｅの間に設けられている。駆動回路４１は、例えば、降圧型スイッチングレギュレータ（ＤＣ－ＤＣコンバータ）で構成されている。なお、駆動回路４１は、降圧型には限られず、昇圧型であってもよい。また、駆動回路４１は、スイッチングレギュレータには限られず、例えばリニアレギュレータでもよい。 The drive circuit 41 is a circuit (constant current circuit) that supplies a drive current for lighting the first light source 10 and the second light source 20 based on the voltage Vbat of the battery 2. is provided. The drive circuit 41 is composed of, for example, a step-down switching regulator (DC-DC converter). Note that the drive circuit 41 is not limited to a step-down type, and may be a step-up type. Further, the drive circuit 41 is not limited to a switching regulator, and may be a linear regulator, for example.
　分圧回路４２は、駆動回路４１と端子Ｅの間のノードＮの電圧（駆動回路４１の出力電圧Ｖｏｕｔ）を分圧する回路である。分圧回路４２は、例えば、ノードＮと接地（ＧＮＤ）との間に直列接続された２つの抵抗を含んで構成される。ノードＮの電圧（出力電圧Ｖｏｕｔ）は、２つの抵抗により分圧される。 The voltage dividing circuit 42 is a circuit that divides the voltage of the node N between the driving circuit 41 and the terminal E (the output voltage Vout of the driving circuit 41). The voltage dividing circuit 42 includes, for example, two resistors connected in series between the node N and ground (GND). The voltage of node N (output voltage Vout) is divided by two resistors.
　記憶回路４４は、マイコン４５における制御を実行させるためのプログラムや各種のデータなどを記憶する回路であり、例えば、半導体メモリで構成されている。なお、記憶回路４４には、第１光源１０の電圧ＶＦ１に関するデータや、第２光源２０の電圧ＶＦ２に関するデータなども記憶されている。 The storage circuit 44 is a circuit that stores programs and various data for executing control in the microcomputer 45, and is composed of a semiconductor memory, for example. The storage circuit 44 also stores data regarding the voltage VF1 of the first light source 10, data regarding the voltage VF2 of the second light source 20, and the like.
　ところで、第１光源１０の電圧ＶＦ１や第２光源２０の電圧ＶＦ２は、常に一定ではなく、固体差によるバラツキや、温度などによる変動がある。このため、記憶回路４４には、電圧ＶＦ１および電圧ＶＦ２の値が、それぞれ、上限と下限を有する正常範囲として記憶されている。以下では、電圧ＶＦ１に対応する正常範囲を範囲Ｒ１とし、電圧ＶＦ２に対応する正常範囲を範囲Ｒ２とする。なお、範囲Ｒ１は「第１範囲」に相当し、範囲Ｒ２は「第２範囲」に相当する。記憶回路４４には、範囲Ｒ１，Ｒ２が、それぞれ分圧回路４２の分圧比（抵抗比）に応じた値（範囲）に変換されて記憶されている。 By the way, the voltage VF1 of the first light source 10 and the voltage VF2 of the second light source 20 are not always constant, but vary due to individual differences and temperature. Therefore, the storage circuit 44 stores the values of the voltage VF1 and the voltage VF2 as normal ranges having upper and lower limits. Hereinafter, the normal range corresponding to voltage VF1 is defined as range R1, and the normal range corresponding to voltage VF2 is defined as range R2. Note that the range R1 corresponds to the "first range" and the range R2 corresponds to the "second range". In the storage circuit 44, the ranges R1 and R2 are converted into values (ranges) corresponding to the voltage dividing ratio (resistance ratio) of the voltage dividing circuit 42 and stored.
　図１に示すように、本実施形態の点灯回路４０では、記憶回路４４はマイコン４５と別体に設けられているが、これには限られず、記憶回路４４とマイコン４５が一体に構成されていてもよい。 As shown in FIG. 1, in the lighting circuit 40 of the present embodiment, the storage circuit 44 is provided separately from the microcomputer 45. However, the present invention is not limited to this, and the storage circuit 44 and the microcomputer 45 are integrated. may
＜マイコン４５について＞
　マイコン４５は、車両用灯具１の動作を制御する回路であり、「制御回路」に相当する。なお、本実施形態では、第１光源１０及び第２光源２０を点灯させる際、サンプリングモードが設けられる。サンプリングモードでは、マイコン４５は、所定の周期Ｔ（後述）でスイッチＳＷ１，ＳＷ２をオンオフし、第１光源１０及び第２光源２０をそれぞれ間欠的に点灯させる。 <About microcomputer 45>
The microcomputer 45 is a circuit that controls the operation of the vehicle lamp 1 and corresponds to a "control circuit". In addition, in this embodiment, when the first light source 10 and the second light source 20 are turned on, a sampling mode is provided. In the sampling mode, the microcomputer 45 turns on and off the switches SW1 and SW2 at a predetermined cycle T (described later) to intermittently light the first light source 10 and the second light source 20, respectively.
　図２は、マイコン４５に実現される機能ブロックの一例を示す図である。なお、マイコン４５は、ハードウェア構成としてはコンピュータのＣＰＵやメモリをはじめとする素子や回路で実現され、ソフトウェア構成としてはコンピュータプログラム等によって実現されるが、図２では適宜、それらの連携によって実現される機能ブロックとして示している。
　本実施形態のマイコン４５は、制御部４５１、検出部４５２、及び送信部４５３を含んで構成される。 FIG. 2 is a diagram showing an example of functional blocks implemented in the microcomputer 45. As shown in FIG. The microcomputer 45 is implemented by elements and circuits such as a computer CPU and memory as hardware configuration, and is implemented by computer programs etc. as software configuration. is shown as a function block to be implemented.
The microcomputer 45 of this embodiment includes a control section 451 , a detection section 452 and a transmission section 453 .
　制御部４５１は、車両側ＥＣＵ（不図示）から入力される制御信号Ｓ１に基づいて、スイッチＳＷ１及びスイッチＳＷ２を、それぞれ、オンオフする。換言すると、制御部４５１は、スイッチＳＷ１のオンオフを制御することにより、第１光源１０を点灯又は消灯させる。また、制御部４５１は、スイッチＳＷ２のオンオフを制御することにより、第２光源２０を点灯又は消灯させる。 The control unit 451 turns on and off the switches SW1 and SW2 based on the control signal S1 input from the vehicle-side ECU (not shown). In other words, the controller 451 turns on or off the first light source 10 by controlling the on/off of the switch SW1. Further, the control unit 451 turns on or off the second light source 20 by controlling the on/off of the switch SW2.
　検出部４５２は、分圧回路４２の出力（出力電圧Ｖｏｕｔの分圧電圧）に基づいて、第１光源１０及び第２光源２０の異常の有無を検出する。なお、本実施形態において、分圧回路４２と接続されるマイコン４５の入力ポートは、アナログ－デジタル変換の機能を有するＡ／Ｄ変換入力ポートで構成されており、分圧回路４２の出力は、マイコン４５の入力ポートでデジタル信号（デジタルデータ）に変換される。ただし、これには限られず、例えば、分圧回路４２にＡ/Ｄ変換回路を設けて、デジタル信号を入力するようにしてもよい。 The detection unit 452 detects whether or not the first light source 10 and the second light source 20 are abnormal based on the output of the voltage dividing circuit 42 (divided voltage of the output voltage Vout). In this embodiment, the input port of the microcomputer 45 connected to the voltage dividing circuit 42 is composed of an A/D conversion input port having an analog-to-digital conversion function, and the output of the voltage dividing circuit 42 is It is converted into a digital signal (digital data) at the input port of the microcomputer 45 . However, it is not limited to this, and for example, an A/D conversion circuit may be provided in the voltage dividing circuit 42 to input a digital signal.
　そして、検出部４５２は、分圧回路４２から取得したデータと、記憶回路４４に記憶されたデータとの比較を行なう。なお、前述したように、記憶回路４４に記憶される範囲（範囲Ｒ１，Ｒ２）の値は、分圧回路４２の分圧比に応じて変換されている。このため、検出部４５２において分圧回路４２のデータと記憶回路４４のデータを比較することは、駆動回路４１の出力電圧Ｖｏｕｔと、実際の正常範囲（範囲Ｒ１，Ｒ２）とを比較することと等価である。 Then, the detection unit 452 compares the data acquired from the voltage dividing circuit 42 with the data stored in the storage circuit 44 . As described above, the values in the ranges (ranges R1 and R2) stored in the storage circuit 44 are converted according to the voltage dividing ratio of the voltage dividing circuit 42. FIG. Therefore, comparing the data in the voltage dividing circuit 42 and the data in the storage circuit 44 in the detection unit 452 means comparing the output voltage Vout of the driving circuit 41 with the actual normal ranges (ranges R1 and R2). are equivalent.
　検出部４５２は、出力電圧Ｖｏｕｔが範囲Ｒ１に含まれるか否かに基づいて、第１光源１０の異常を検出する。また、出力電圧Ｖｏｕｔが範囲Ｒ２に含まれるか否かに基づいて、第２光源２０の異常を検出する。なお、各光源の異常の検出のタイミング（期間）については後述する。 The detection unit 452 detects an abnormality of the first light source 10 based on whether the output voltage Vout is included in the range R1. Further, an abnormality of the second light source 20 is detected based on whether the output voltage Vout is included in the range R2. The timing (period) for detecting an abnormality in each light source will be described later.
　送信部４５３は、検出部４５２において異常が検出された場合、車両側ＥＣＵ（不図示）にその旨を示す検出信号Ｓ２を送信する。 When the detection unit 452 detects an abnormality, the transmission unit 453 transmits a detection signal S2 indicating that fact to the vehicle-side ECU (not shown).
＜＜異常の検出について＞＞
　図３は、本実形態の点灯回路４０による異常検出の動作を説明するための図である。なお、図３に示すスイッチＳＷ１，ＳＷ２のパルス状の波形において、「ハイレベル」はオン状態（導通状態）であることを示し、「ローレベル」はオフ状態（非導通状態）であることを示している。 << About detection of anomalies >>
FIG. 3 is a diagram for explaining the operation of abnormality detection by the lighting circuit 40 of the present embodiment. In the pulse waveforms of the switches SW1 and SW2 shown in FIG. 3, "high level" indicates an ON state (conducting state), and "low level" indicates an OFF state (non-conducting state). showing.
　図に示す周期Ｔは、例えば５ｍｓの短い期間であり、この周期Ｔにおいて、第1光源１０と第２光源２０をそれぞれ消灯させる期間（期間ＴＡ，ＴＣ）が設けられている。すなわち、周期Ｔにおいて、第１光源１０及び第２光源２０は、それぞれ間欠的に点灯するように制御される。図３における時刻ｔ０以前は、第１光源１０と第２光源２０をともに点灯させており、時刻ｔ０でサンプリングモードに入る。 The cycle T shown in the figure is a short period of, for example, 5 ms, and in this cycle T, periods (periods TA, TC) are provided for turning off the first light source 10 and the second light source 20, respectively. That is, in the period T, the first light source 10 and the second light source 20 are controlled to be lit intermittently. Before time t0 in FIG. 3, both the first light source 10 and the second light source 20 are turned on, and the sampling mode is entered at time t0.
　時刻ｔ０～時刻ｔ１の期間ＴＡでは、マイコン４５の制御部４５１は、スイッチＳＷ１をオフし、スイッチＳＷ２をオンする。すなわち、第１光源１０を点灯させ、第２光源２０を消灯させる。よって、期間ＴＡにおいて、第１光源１０が正常であればノードＮの電圧はＶＦ１になる。マイコン４５の検出部４５２は、分圧回路４２の出力と記憶回路４４のデータを比較し、駆動回路４１の出力電圧Ｖｏｕｔが、電圧ＶＦ１に対応する範囲Ｒ１に含まれるか否かを検出する。 During a period TA from time t0 to time t1, the control section 451 of the microcomputer 45 turns off the switch SW1 and turns on the switch SW2. That is, the first light source 10 is turned on and the second light source 20 is turned off. Therefore, during the period TA, if the first light source 10 is normal, the voltage of the node N becomes VF1. A detection unit 452 of the microcomputer 45 compares the output of the voltage dividing circuit 42 and the data of the storage circuit 44, and detects whether the output voltage Vout of the driving circuit 41 is included in the range R1 corresponding to the voltage VF1.
　時刻ｔ１～時刻ｔ２の期間ＴＢでは、マイコン４５の制御部４５１は、スイッチＳＷ１とスイッチＳＷ２をともにオフにする。すなわち、第１光源１０と第２光源２０をともに点灯させる。よって、期間ＴＢにおいて、第１光源１０と第２光源２０がともに正常であれば、ノードＮの電圧は（ＶＦ１＋ＶＦ２）になる。なお、本実施形態において、この期間ＴＢには各光源の異常の検出を行わない。この理由については後述する。 During the period TB from time t1 to time t2, the control section 451 of the microcomputer 45 turns off both the switches SW1 and SW2. That is, both the first light source 10 and the second light source 20 are turned on. Therefore, if both the first light source 10 and the second light source 20 are normal during the period TB, the voltage of the node N becomes (VF1+VF2). In this embodiment, abnormality detection of each light source is not performed during this period TB. The reason for this will be described later.
　時刻ｔ２～時刻ｔ３の期間ＴＣでは、マイコン４５の制御部４５１は、スイッチＳＷ１をオンし、スイッチＳＷ２をオフする。すなわち、第１光源１０を消灯させ、第２光源２０を点灯させる。よって、期間ＴＣにおいて、第２光源２０が正常であればノードＮの電圧はＶＦ２になる。マイコン４５の検出部４５２は、分圧回路４２の出力と記憶回路４４のデータを比較し、駆動回路４１の出力電圧Ｖｏｕｔが、電圧ＶＦ２に対応する範囲Ｒ２に含まれるか否かを検出する。 During the period TC from time t2 to time t3, the control section 451 of the microcomputer 45 turns on the switch SW1 and turns off the switch SW2. That is, the first light source 10 is turned off and the second light source 20 is turned on. Therefore, during the period TC, if the second light source 20 is normal, the voltage of the node N becomes VF2. A detection unit 452 of the microcomputer 45 compares the output of the voltage dividing circuit 42 and the data of the storage circuit 44, and detects whether the output voltage Vout of the driving circuit 41 is included in the range R2 corresponding to the voltage VF2.
　以下、同様の処理を周期Ｔで繰り返し行う。これにより、第１光源１０と第２光源２０が、それぞれ、異なるタイミングで間欠的に点灯されている状態となる。なお、周期Ｔは、「所定周期」に相当し、期間ＴＡと期間ＴＣのうちの一方（例えば期間ＴＡ）は、「１期間」に相当し、他方（例えば期間ＴＣ）は「第２期間」に相当する。また、期間ＴＢは「第３期間」に相当する。 After that, the same processing is repeated with a period T. As a result, the first light source 10 and the second light source 20 are intermittently lit at different timings. Note that the period T corresponds to a "predetermined period", one of the period TA and the period TC (for example, the period TA) corresponds to "one period", and the other (for example, the period TC) corresponds to the "second period". corresponds to Also, the period TB corresponds to the "third period".
　図４は、異常の判定についての説明図である。
　図には、第１光源１０が正常に点灯した場合の電圧ＶＦ１の範囲Ｒ１と、第２光源２０が正常に点灯した場合の電圧ＶＦ２の範囲Ｒ２が示されている。本実施形態では、第１光源１０の発光素子１１の数と、第２光源２０の発光素子２１の数が異なるため、範囲Ｒ１と範囲Ｒ２が異なっている。 FIG. 4 is an explanatory diagram of abnormality determination.
The figure shows a range R1 of the voltage VF1 when the first light source 10 is normally lit and a range R2 of the voltage VF2 when the second light source 20 is normally lit. In this embodiment, since the number of light emitting elements 11 of the first light source 10 and the number of light emitting elements 21 of the second light source 20 are different, the range R1 and the range R2 are different.
　マイコン４５の検出部４５２は、異常の検出を行う期間（期間ＴＡ，期間ＴＣ）により、異常検出の対象の光源（第１光源１０と第２光源２０の何れか）を把握できる。そして、検出部４５２は、出力電圧Ｖｏｕｔが、その光源の正常範囲内に含まれれば「正常」と判定し、正常範囲内に含まれなければ「異常」と判定する。 The detection unit 452 of the microcomputer 45 can grasp the light source (either the first light source 10 or the second light source 20) for which abnormality detection is performed, depending on the period (period TA, period TC) during which abnormality is detected. If the output voltage Vout is within the normal range of the light source, the detection unit 452 determines that it is "normal", and if it is not within the normal range, it determines that it is "abnormal".
　例えば、第１光源１０を点灯させ、第２光源２０を消灯させる期間ＴＡでは、検出部４５２は、出力電圧Ｖｏｕｔ（ノードＮの電圧）が範囲Ｒ１に含まれるか否かを検出する。具体的には、出力電圧Ｖｏｕｔが、図の一点鎖線で示す電圧の場合、範囲Ｒ１に含まれるので、検出部４５２は、第１光源１０が正常であると判定する。出力電圧Ｖｏｕｔが、図の破線で示す電圧の場合、範囲Ｒ１に含まれないので、検出部４５２は、第１光源１０が異常であると判定する。 For example, during a period TA during which the first light source 10 is turned on and the second light source 20 is turned off, the detection unit 452 detects whether the output voltage Vout (the voltage at the node N) is within the range R1. Specifically, when the output voltage Vout is the voltage indicated by the dashed-dotted line in the figure, it is included in the range R1, so the detection unit 452 determines that the first light source 10 is normal. When the output voltage Vout is the voltage indicated by the dashed line in the figure, it is not included in the range R1, so the detection unit 452 determines that the first light source 10 is abnormal.
　また、第２光源２０を点灯させ、第１光源１０を消灯させる期間ＴＣでは、検出部４５２は、出力電圧Ｖｏｕｔ（ノードＮの電圧）が範囲Ｒ２に含まれるか否かを検出する。具体的には、出力電圧Ｖｏｕｔが、図の破線で示す電圧の場合、範囲Ｒ２に含まれるので、検出部４５２は、第２光源２０が正常であると判定する。出力電圧Ｖｏｕｔが、図の一点鎖線で示す電圧の場合、範囲Ｒ２に含まれないので、検出部４５２は、第２光源２０が異常であると判定する。 Also, during the period TC in which the second light source 20 is turned on and the first light source 10 is turned off, the detection unit 452 detects whether the output voltage Vout (the voltage at the node N) is included in the range R2. Specifically, when the output voltage Vout is the voltage indicated by the dashed line in the figure, it is included in the range R2, so the detection unit 452 determines that the second light source 20 is normal. When the output voltage Vout is the voltage indicated by the dashed-dotted line in the drawing, the detection unit 452 determines that the second light source 20 is abnormal because it is not included in the range R2.
　また、前述したように、第１光源１０と第２光源２０をともに点灯させる期間ＴＢでは、検出部４５２は異常の検出を行わない。これは、期間ＴＢにおいて（ＶＦ１＋ＶＦ２）の正常範囲を設定して異常の検出を行うと、正しく検出できないおそれがあるからである。例えば、ＶＦ２＞ＶＦ１である場合に、第１光源１０の発光素子１１がショートすると、出力電圧ＶｏｕｔはＶＦ２となる。このときの電圧ＶＦ２の値が、（ＶＦ１＋ＶＦ２）の正常範囲に含まれてしまうおそれがあり、正常範囲に含まれると、第１光源１０の異常を検出できないことになる。 Also, as described above, the detection unit 452 does not detect an abnormality during the period TB in which both the first light source 10 and the second light source 20 are turned on. This is because if the normal range of (VF1+VF2) is set in the period TB and the abnormality is detected, there is a possibility that the abnormality cannot be detected correctly. For example, when VF2>VF1, if the light emitting element 11 of the first light source 10 is short-circuited, the output voltage Vout becomes VF2. The value of the voltage VF2 at this time may fall within the normal range of (VF1+VF2).
　なお、出力電圧Ｖｏｕｔが正常範囲の上限よりも高い場合（例えばＭＡＸ値の場合）は、発光素子（発光素子１１，２１）のオープン（断線）による異常と判定することができる。また、出力電圧Ｖｏｕｔが正常範囲の下限よりも低い場合（例えばゼロの場合）は、発光素子（発光素子１１，２１）のショート（短絡）による異常と判定することができる。このように、オープンとショートを区別して検出することもできる。 If the output voltage Vout is higher than the upper limit of the normal range (for example, in the case of the MAX value), it can be determined that there is an abnormality due to open (disconnection) of the light emitting elements (light emitting elements 11 and 21). Also, when the output voltage Vout is lower than the lower limit of the normal range (for example, when it is zero), it can be determined that there is an abnormality due to a short circuit of the light emitting elements (light emitting elements 11 and 21). In this way, an open circuit and a short circuit can be detected separately.
　検出部４５２により第１光源１０と第２光源２０の何れかに異常が発生していることが検出されると、送信部４５３は、その結果を示す検出信号Ｓ２を、車両側ＥＣＵに送信する。 When the detection unit 452 detects that one of the first light source 10 and the second light source 20 is abnormal, the transmission unit 453 transmits a detection signal S2 indicating the result to the vehicle-side ECU. .
　車両側ＥＣＵは、検出信号Ｓ２を受信すると、運転手などに異常が生じていることを示す通知を行う。通知方法としては、例えば、発光や表示などの視覚的通知、音などの聴覚的通知、振動などの触覚的通知などがあり、車両側ＥＣＵは、そのうち何れかを用いて通知を行う。 When the vehicle-side ECU receives the detection signal S2, it notifies the driver or the like that an abnormality has occurred. Examples of notification methods include visual notification such as light emission and display, auditory notification such as sound, and tactile notification such as vibration.
　以上説明したように、本実施形態の点灯回路４０は、駆動電流の電流経路のうちの１箇所（ノードＮ）の電圧のみを用いて第１光源１０の異常と第２光源２０の異常をそれぞれ検出することが出来る。つまり、分圧回路４２、及びＡ/Ｄ変換回路（本実施形態では、マイコン４５のＡ／Ｄ変換入力ポート）がそれぞれ１つでよい。よって、簡易な構成で、各光源の異常を検出可能である。 As described above, the lighting circuit 40 of the present embodiment uses only the voltage at one point (node N) in the current path of the driving current to detect the abnormality of the first light source 10 and the abnormality of the second light source 20 respectively. can be detected. That is, one voltage dividing circuit 42 and one A/D conversion circuit (in this embodiment, the A/D conversion input port of the microcomputer 45) are sufficient. Therefore, an abnormality of each light source can be detected with a simple configuration.
＜＜変形例＞＞
　図５は、点灯回路４０による異常検出の動作の変形例を説明するための図である。
　なお、車両用灯具１（第１光源１０，第２光源２０，点灯回路４０）の構成は前述の実施形態と同じであり、同一符号を用いている。 <<Modification>>
FIG. 5 is a diagram for explaining a modification of the abnormality detection operation by the lighting circuit 40. As shown in FIG.
The configuration of the vehicle lamp 1 (the first light source 10, the second light source 20, and the lighting circuit 40) is the same as in the above-described embodiment, and the same reference numerals are used.
　この変形例では、第１光源１０及び第２光源２０について、それぞれ、前述の実施形態よりも消灯時間を長く（点灯時間を短く）している。 In this modification, each of the first light source 10 and the second light source 20 has a longer turn-off time (shorter turn-on time) than in the above-described embodiment.
　時刻ｔ１０～時刻ｔ１２の期間ＴＤ及び期間ＴＥでは、マイコン４５の制御部４５１は、スイッチＳＷ１をオフし、スイッチＳＷ２をオンする。すなわち、第１光源１０を点灯させ、第２光源２０を消灯させる。この期間ＴＤ，ＴＥでは第１光源１０が正常であればノードＮの電圧はＶＦ１になる。 During periods TD and TE from time t10 to time t12, the control unit 451 of the microcomputer 45 turns off the switch SW1 and turns on the switch SW2. That is, the first light source 10 is turned on and the second light source 20 is turned off. During the periods TD and TE, if the first light source 10 is normal, the voltage of the node N becomes VF1.
　マイコン４５の検出部４５２は、期間ＴＤにおいて、分圧回路４２の出力と記憶回路４４のデータを比較し、駆動回路４１の出力電圧Ｖｏｕｔが、電圧ＶＦ１に対応する範囲Ｒ１に含まれるか否かを検出する。なお、期間ＴＥにおいて異常の検出を行っても良い。 The detection unit 452 of the microcomputer 45 compares the output of the voltage dividing circuit 42 and the data of the storage circuit 44 in the period TD to determine whether the output voltage Vout of the driving circuit 41 is included in the range R1 corresponding to the voltage VF1. to detect It should be noted that the abnormality may be detected during the period TE.
　時刻ｔ１２～時刻ｔ１３の期間ＴＦでは、マイコン４５の制御部４５１は、スイッチＳＷ１とスイッチＳＷ２をともにオンする。すなわち、第１光源１０と第２光源２０をともに消灯させる。これにより、ノードＮの電圧は接地電位（アース）になる。この期間ＴＦでは、異常の検出は行わない。 During the period TF from time t12 to time t13, the control section 451 of the microcomputer 45 turns on both the switches SW1 and SW2. That is, both the first light source 10 and the second light source 20 are turned off. As a result, the voltage of the node N becomes the ground potential (earth). No abnormality is detected during this period TF.
　時刻ｔ１３～時刻ｔ１４の期間ＴＧでは、マイコン４５の制御部４５１は、スイッチＳＷ１をオンし、スイッチＳＷ２をオフする。すなわち、第１光源１０を消灯させ、第２光源２０を点灯させる。この期間ＴＧでは第２光源２０が正常であればノードＮの電圧はＶＦ２になる。マイコン４５の検出部４５２は、分圧回路４２の出力と記憶回路４４のデータを比較し、駆動回路４１の出力電圧Ｖｏｕｔが、電圧ＶＦ２に対応する範囲Ｒ２に含まれるか否かを検出する。 During the period TG from time t13 to time t14, the control section 451 of the microcomputer 45 turns on the switch SW1 and turns off the switch SW2. That is, the first light source 10 is turned off and the second light source 20 is turned on. During this period TG, the voltage of the node N becomes VF2 if the second light source 20 is normal. A detection unit 452 of the microcomputer 45 compares the output of the voltage dividing circuit 42 and the data of the storage circuit 44, and detects whether the output voltage Vout of the driving circuit 41 is included in the range R2 corresponding to the voltage VF2.
　以下、同様の処理を周期Ｔで繰り返し行う。これにより、第１光源１０と第２光源２０が、それぞれ、間欠的に点灯されている状態となる。この変形例では、前述の実施形態（図３）と比べて、第１光源１０及び第２光源２０の点灯時間が短く（消灯時間が長く）なっている。また、両方点灯する期間がなく、両方消灯する期間（期間ＴＧ）がある。よって、前述の実施形態よりも暗くなる。なお、周期Ｔは、「所定周期」に相当し、期間ＴＤと期間ＴＧのうちの一方（例えば期間ＴＤ）は、「第１期間」に相当し、他方（例えば期間ＴＧ）は「第２期間」に相当する。 After that, the same processing is repeated with a period T. As a result, the first light source 10 and the second light source 20 are intermittently lit. In this modification, the lighting time of the first light source 10 and the second light source 20 is shorter (the lighting time is longer) than in the above-described embodiment (FIG. 3). Moreover, there is no period during which both are lit, and there is a period (period TG) during which both are extinguished. Therefore, it becomes darker than the previous embodiment. Note that the period T corresponds to the "predetermined period", one of the period TD and the period TG (for example, the period TD) corresponds to the "first period", and the other (for example, the period TG) corresponds to the "second period." Equivalent to
　この変形例においても、第１光源１０及び第２光源２０の一方を点灯させ、他方を消灯させる期間を設けることで、第１光源１０と第２光源２０の異常の検出を行うことができる。 Also in this modified example, by providing a period in which one of the first light source 10 and the second light source 20 is turned on and the other is turned off, an abnormality of the first light source 10 and the second light source 20 can be detected.
＝＝＝＝＝まとめ＝＝＝＝＝
　以上、本実施形態の車両用灯具１について説明した。車両用灯具１の点灯回路４０は、第１光源１０に並列に設けられるスイッチＳＷ１と、第２光源２０に並列に設けられるスイッチＳＷ２と、第１光源１０及び第２光源２０に駆動電流を供給する駆動回路４１と、スイッチＳＷ１及びスイッチＳＷ２のオンオフを制御することにより、第１光源１０及び第２光源２０をそれぞれ点灯又は消灯させるマイコン４５を備えている。そして、マイコン４５は、一方の光源（例えば第２光源２０）を間欠的に点灯させている状態において、第２光源２０を消灯させ、第１光源１０を点灯させる期間ＴＡに、駆動回路４１の出力電圧Ｖｏｕｔに基づいて、第１光源１０の異常の検出を行う。これにより、簡易な構成で、第１光源１０の異常を検出可能である。 =====Summary=====
The vehicle lamp 1 of the present embodiment has been described above. The lighting circuit 40 of the vehicle lamp 1 supplies a drive current to the switch SW1 provided in parallel with the first light source 10, the switch SW2 provided in parallel with the second light source 20, and the first light source 10 and the second light source 20. and a microcomputer 45 for turning on or off the first light source 10 and the second light source 20 by controlling the on/off of the switches SW1 and SW2. Then, in a state in which one light source (for example, the second light source 20) is intermittently lit, the microcomputer 45 turns off the second light source 20 and turns on the first light source 10 during the period TA during which the drive circuit 41 is turned on. Abnormality of the first light source 10 is detected based on the output voltage Vout. This makes it possible to detect an abnormality in the first light source 10 with a simple configuration.
　また、マイコン４５は、他方の光源（例えば第１光源１０）を間欠的に点灯させている状態において、第１光源１０を消灯させ、第２光源２０を点灯させる期間ＴＣに、駆動回路４１の出力電圧Ｖｏｕｔに基づいて、第２光源２０の異常の検出を行う。これにより、簡易な構成で、第２光源２０の異常を検出可能である。 In a state where the other light source (for example, the first light source 10) is intermittently lit, the microcomputer 45 turns off the first light source 10 and turns on the second light source 20 during the period TC. Abnormality of the second light source 20 is detected based on the output voltage Vout. This makes it possible to detect an abnormality in the second light source 20 with a simple configuration.
　また、マイコン４５は、第１光源１０及び第２光源２０が間欠的に点灯するよう、スイッチＳＷ１及びスイッチＳＷ２のオンオフの制御を、周期Ｔで繰り返し、期間ＴＡ及び期間ＴＣは、それぞれ、周期Ｔに含まれる。これにより、簡易な構成で、第１光源１０と第２光源２０の異常を検出可能である。 In addition, the microcomputer 45 repeats the ON/OFF control of the switches SW1 and SW2 in a cycle T so that the first light source 10 and the second light source 20 are intermittently lit. include. This makes it possible to detect an abnormality in the first light source 10 and the second light source 20 with a simple configuration.
　また、周期Ｔには、第１光源１０と第２光源２０をともに点灯させる期間ＴＢが含まれる。これにより、各光源を間欠的にさせている状態においても明るくするようにできる。なお、この期間ＴＢにおいて第１光源１０及び第２光源２０の異常の検出を行わないことにより、誤検出を抑制することができる。 The cycle T also includes a period TB during which both the first light source 10 and the second light source 20 are turned on. This makes it possible to brighten even when the light sources are intermittently turned on. By not detecting an abnormality in the first light source 10 and the second light source 20 during the period TB, erroneous detection can be suppressed.
　また、マイコン４５は、期間ＴＡでは、出力電圧Ｖｏｕｔが範囲Ｒ１に含まれるか否かに基づいて、第１光源１０の異常の検出を行い、期間ＴＣでは、出力電圧Ｖｏｕｔが、範囲Ｒ２に含まれるか否かに基づいて、第２光源２０の光源の異常の検出を行う。これにより、第１光源１０と第２光源２０の異常をそれぞれ確実に検出することができる。 Further, the microcomputer 45 detects abnormality of the first light source 10 based on whether the output voltage Vout is included in the range R1 in the period TA, and the output voltage Vout is included in the range R2 in the period TC. Abnormality of the light source of the second light source 20 is detected based on whether or not the light source of the second light source 20 is detected. As a result, anomalies of the first light source 10 and the second light source 20 can be reliably detected.
　また、第１光源１０は、少なくとも１つの発光素子１１を有し、第２光源２０は、少なくとも１つの発光素子２１を有している。本実施形態の点灯回路４０では、第１光源１０の発光素子１１の数と、第２光源２０の発光素子２１の数が異なっていても、それぞれの光源について異常を確実に検出することができるので、この場合より効果的である。 Also, the first light source 10 has at least one light emitting element 11 and the second light source 20 has at least one light emitting element 21 . In the lighting circuit 40 of this embodiment, even if the number of the light emitting elements 11 of the first light source 10 and the number of the light emitting elements 21 of the second light source 20 are different, it is possible to reliably detect an abnormality in each light source. Therefore, it is more effective in this case.
　また、本実施形態の点灯回路４０は、車両に用いられる灯具（車両用灯具１）に好適である。ただし、これには限られず、例えば、街路灯などの灯具に適用されても良い。この場合においても、同様の効果を得ることができる。 Also, the lighting circuit 40 of the present embodiment is suitable for a lamp used in a vehicle (vehicle lamp 1). However, the present invention is not limited to this, and may be applied to lighting fixtures such as street lights, for example. Similar effects can be obtained in this case as well.
　また、前述の実施形態では、第１光源１０をロービーム用の光源とし、第２光源２０をハイビーム用の光源としたが、これには限られない。例えば、第１光源１０がハイビーム用の光源でもよく、第２光源２０がロービーム用の光源でもよい。 Also, in the above embodiment, the first light source 10 is a low beam light source and the second light source 20 is a high beam light source, but the present invention is not limited to this. For example, the first light source 10 may be a high beam light source, and the second light source 20 may be a low beam light source.
　また、ロービームとハイビームには限られず、他のランプ（例えば、ＤＲＬ（Daytime Running Lamp）、ＣＬＬ（Clearance Lamp）、ターンシグナルランプなど）の組み合わせでもよい。なお、ＤＲＬとは、日中に、走行中の車両の存在を歩行者や対向車の運転者等に知らせるために点灯するランプである。ＣＬＬとは車両の幅方向の大きさとその存在を示すために車両の前面に装備するランプである。ターンシグナルランプとは、車両の旋回および進路変更等を前方および後方の車両の運転者に知らせるために点滅するランプである。 Also, it is not limited to low beam and high beam, and may be a combination of other lamps (for example, DRL (Daytime Running Lamp), CLL (Clearance Lamp), turn signal lamp, etc.). A DRL is a lamp that lights up during the day to notify pedestrians and drivers of oncoming vehicles of the presence of a vehicle in motion. A CLL is a lamp mounted on the front of a vehicle to indicate the width of the vehicle and its presence. A turn signal lamp is a lamp that blinks to notify drivers of vehicles ahead and behind when the vehicle turns, changes course, and the like.
　また、前述の実施形態では、光源が２つ（第１光源１０，第２光源２０）であったが、これには限られず、３つ以上であってもよい。この場合も、同様の制御を行うことで、各光源の異常を検出することができる。 Also, in the above-described embodiment, there were two light sources (the first light source 10 and the second light source 20), but the number is not limited to this, and may be three or more. Also in this case, by performing similar control, an abnormality of each light source can be detected.
　上記の実施形態は、本発明の理解を容易にするためのものであり、本発明を限定して解釈するためのものではない。また、本発明は、その趣旨を逸脱することなく、変更や改良され得るとともに、本発明にはその等価物が含まれるのはいうまでもない。 The above embodiments are intended to facilitate understanding of the present invention, and are not intended to limit and interpret the present invention. Further, the present invention can be modified and improved without departing from its spirit, and it goes without saying that the present invention includes equivalents thereof.
　本国際出願は、２０２１年１２月９日に出願された日本国特許出願である特願２０２１－１９９８６２号に基づく優先権を主張するものであり、当該日本国特許出願である特願２０２１－１９９８６２号の全内容は、本国際出願に援用される。 This international application claims priority based on Japanese Patent Application No. 2021-199862 filed on December 9, 2021, which is Japanese Patent Application No. 2021-199862. The entire contents of this International Application are incorporated by reference.
　本発明の特定の実施の形態についての上記説明は、例示を目的として提示したものである。それらは、網羅的であったり、記載した形態そのままに本発明を制限したりすることを意図したものではない。数多くの変形や変更が、上記の記載内容に照らして可能であることは当業者に自明である。 The foregoing descriptions of specific embodiments of the invention have been presented for purposes of illustration. They are not intended to be exhaustive or to limit the invention to the precise forms described. Those skilled in the art will appreciate that many variations and modifications are possible in light of the above description.
１　車両用灯具
２　バッテリー
１０　第１光源
１１　発光素子
２０　第２光源
２１　発光素子
４０　点灯回路
４１　駆動回路
４２　分圧回路
４４　記憶回路
４５　マイコン
４５１　制御部
４５２　検出部
４５３　送信部
ＳＷ０　点灯スイッチ
ＳＷ１，ＳＷ２　スイッチ
Ａ～Ｆ　端子 1 vehicle lamp 2 battery 10 first light source 11 light emitting element 20 second light source 21 light emitting element 40 lighting circuit 41 driving circuit 42 voltage dividing circuit 44 memory circuit 45 microcomputer 451 control section 452 detection section 453 transmission section SW0 lighting switches SW1 and SW2 Switch A to F terminals

Claims (8)

  1. 　第１光源と、前記第１光源に直列接続された第２光源と、を備える灯具に適用される点灯回路であって、
    　前記第１光源に並列に設けられる第１スイッチと、
    　前記第２光源に並列に設けられる第２スイッチと、
    　前記第１及び第２光源に駆動電流を供給する駆動回路と、
    　前記第１及び第２スイッチのオンオフを制御することにより、前記第１及び第２光源をそれぞれ点灯又は消灯させる制御回路と、
    　を備え、
    　前記制御回路は、前記第１及び第２光源の一方の光源を間欠的に点灯させている状態において、前記一方の光源を消灯させ、前記第１及び第２光源の他方の光源を点灯させる第１期間に、前記駆動回路の出力電圧に基づいて、前記他方の光源の異常の検出を行う、
    　点灯回路。     A lighting circuit applied to a lamp including a first light source and a second light source connected in series with the first light source,
    a first switch provided in parallel with the first light source;
    a second switch provided in parallel with the second light source;
    a drive circuit that supplies a drive current to the first and second light sources;
    a control circuit for turning on or off the first and second light sources by controlling on/off of the first and second switches;
    with
    In a state in which one of the first and second light sources is intermittently lit, the control circuit turns off the one light source and turns on the other light source of the first and second light sources. detecting an abnormality of the other light source based on the output voltage of the drive circuit in one period;
    lighting circuit.
  2. 　請求項１に記載の点灯回路であって、
    　前記制御回路は、前記他方の光源を間欠的に点灯させている状態において、前記他方の光源を消灯させ、前記一方の光源を点灯させる第２期間に、前記駆動回路の出力電圧に基づいて、前記一方の光源の異常の検出を行う、
    　点灯回路。     The lighting circuit according to claim 1,
    In a state in which the other light source is intermittently lit, the control circuit turns off the other light source, and during a second period in which the one light source is turned on, based on the output voltage of the drive circuit, detecting an abnormality in the one light source;
    lighting circuit.
  3. 　請求項２に記載の点灯回路であって、
    　前記制御回路は、前記一方及び他方の光源が間欠的に点灯するよう、前記第１及び第２スイッチのオンオフの制御を、所定周期で繰り返し、
    　前記第１及び第２期間は、それぞれ、前記所定周期に含まれる、
    　点灯回路。     The lighting circuit according to claim 2,
    The control circuit repeats on/off control of the first and second switches at a predetermined cycle so that the one and the other light sources are intermittently lit,
    The first and second periods are each included in the predetermined cycle,
    lighting circuit.
  4. 　請求項３に記載の点灯回路であって、
    　前記所定周期には、前記第１及び第２光源をともに点灯させる第３期間が含まれる、
    　点灯回路。     The lighting circuit according to claim 3,
    The predetermined period includes a third period in which both the first and second light sources are turned on.
    lighting circuit.
  5. 　請求項２～４の何れかに記載の点灯回路であって、
    　前記制御回路は、
    　前記第１期間では、前記出力電圧が第１範囲に含まれるか否かに基づいて、前記他方の光源の異常の検出を行い、
    　前記第２期間では、前記出力電圧が、前記第1範囲とは異なる第２範囲に含まれるか否かに基づいて、前記一方の光源の異常の検出を行う、
    　点灯回路。     The lighting circuit according to any one of claims 2 to 4,
    The control circuit is
    In the first period, an abnormality of the other light source is detected based on whether the output voltage is included in the first range;
    In the second period, an abnormality of the one light source is detected based on whether the output voltage is included in a second range different from the first range.
    lighting circuit.
  6. 　請求項５に記載の点灯回路であって、
    　前記第1及び第２光源は、それぞれ、少なくとも１つの発光素子を有し、
    　前記第１光源の前記発光素子の数と、前記第２光源の前記発光素子の数が異なる、
    　点灯回路。     The lighting circuit according to claim 5,
    each of the first and second light sources has at least one light emitting element;
    The number of the light emitting elements of the first light source is different from the number of the light emitting elements of the second light source,
    lighting circuit.
  7. 　請求項１～４の何れか一項に記載の点灯回路であって、
    　前記灯具は、車両に用いられる車両用灯具である、
    　点灯回路。     The lighting circuit according to any one of claims 1 to 4,
    The lamp is a vehicle lamp used in a vehicle,
    lighting circuit.
  8. 　前記第１及び第２光源と、
    　請求項１～４の何れか一項に記載の点灯回路と、
    　を備える車両用灯具。     the first and second light sources;
    a lighting circuit according to any one of claims 1 to 4;
    A vehicle lamp.
PCT/JP2022/044360 2021-12-09 2022-12-01 Lighting circuit and vehicle lamp WO2023106199A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021-199862 2021-12-09
JP2021199862A JP2023085687A (en) 2021-12-09 2021-12-09 Lighting circuit and vehicle lamp fitting

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016045999A (en) * 2014-08-20 2016-04-04 株式会社デンソー Light emission device
WO2017086220A1 (en) * 2015-11-18 2017-05-26 株式会社小糸製作所 Lighting circuit and vehicular lamp
JP2019114424A (en) * 2017-12-22 2019-07-11 株式会社デンソー Front lighting system for vehicle, breaking of wire detection method
JP2020087830A (en) * 2018-11-29 2020-06-04 株式会社小糸製作所 Lamp failure detector and setting method therefor, luminous source failure detector and setting method therefor, and lamp assembly

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016045999A (en) * 2014-08-20 2016-04-04 株式会社デンソー Light emission device
WO2017086220A1 (en) * 2015-11-18 2017-05-26 株式会社小糸製作所 Lighting circuit and vehicular lamp
JP2019114424A (en) * 2017-12-22 2019-07-11 株式会社デンソー Front lighting system for vehicle, breaking of wire detection method
JP2020087830A (en) * 2018-11-29 2020-06-04 株式会社小糸製作所 Lamp failure detector and setting method therefor, luminous source failure detector and setting method therefor, and lamp assembly

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