WO2023286550A1 - Lamp - Google Patents

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Publication number
WO2023286550A1
WO2023286550A1 PCT/JP2022/024934 JP2022024934W WO2023286550A1 WO 2023286550 A1 WO2023286550 A1 WO 2023286550A1 JP 2022024934 W JP2022024934 W JP 2022024934W WO 2023286550 A1 WO2023286550 A1 WO 2023286550A1
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WO
WIPO (PCT)
Prior art keywords
ground line
line
power supply
voltage
current
Prior art date
Application number
PCT/JP2022/024934
Other languages
French (fr)
Japanese (ja)
Inventor
優 太田
翔平 柳津
Original Assignee
株式会社小糸製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社小糸製作所 filed Critical 株式会社小糸製作所
Publication of WO2023286550A1 publication Critical patent/WO2023286550A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S45/00—Arrangements within vehicle lighting devices specially adapted for vehicle exteriors, for purposes other than emission or distribution of light
    • F21S45/10—Protection of lighting 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
    • H05B47/175—Controlling the light source by remote control
    • H05B47/18—Controlling the light source by remote control via data-bus transmission
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
    • F21W2102/00—Exterior vehicle lighting devices for illuminating purposes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Definitions

  • This disclosure relates to lighting fixtures.
  • the output voltage of the current regulator generally rises significantly. Therefore, by measuring the output voltage of the current regulator, an increase in the impedance of the ground line can be detected.
  • the voltage regulator when using a voltage regulator that applies a predetermined voltage to a light source that includes a light emitting element, the voltage regulator continues to output a predetermined voltage even if the impedance of the ground line to which the light source is connected increases. Therefore, in a lamp using a voltage regulator, it is difficult to detect disconnection or the like of the ground line to which the light source is connected.
  • the present disclosure has been made in view of the conventional problems as described above, and an object thereof is to provide a lamp that can detect an increase in impedance of a ground line while using a voltage regulator. .
  • the main disclosure for solving the above-mentioned problems is a voltage regulator connected to a first power supply line to which a first voltage of a voltage source is applied and a first ground line and applying a second voltage to the second power supply line.
  • a light source connected to the second power supply line and a second ground line connected to the first ground line; a third ground line connected to the second ground line; a connected fourth ground line and a communication line from the light source are connected, a controller for controlling the light source, and a detector for detecting a current flowing through the third ground line or the fourth ground line; and a determination unit that determines whether or not the second ground line is in a high impedance state based on the detection result of the detection unit.
  • FIG. 1 is a diagram showing an example of a vehicle lamp 10;
  • FIG. 7 is a diagram showing an example of a detection unit 71 and a microcomputer 72;
  • FIG. 4 is a diagram for explaining a current path Y1;
  • FIG. It is a figure for demonstrating current path Y2.
  • 4 is a diagram showing an example of a control board 22 on which a comparator 75 is mounted;
  • FIG. 1 is a diagram showing an example configuration of a vehicle lamp 10 that is an embodiment of the present disclosure.
  • the vehicle lamp 10 is, for example, a headlamp including a light source that is lit based on the voltage V1 of the vehicle battery 11 .
  • the vehicle lamp 10 includes a power supply board 20 , an LED (Light Emitting Diode) board 21 , and a control board 22 .
  • the power supply board 20 is a resin board (PCB: Printed Circuit Board) on which a power supply circuit 30 that generates a predetermined voltage V2 to be applied to the light source based on the voltage V1 and a microcomputer 31 are mounted.
  • PCB Printed Circuit Board
  • the term "substrate” means, for example, a PCB substrate on which a conductive wiring pattern made of copper or the like is formed, unless otherwise specified.
  • the voltage V1 of the battery 11 corresponds to the "first voltage”
  • the predetermined voltage V2 corresponds to the "second voltage”.
  • a power supply line PL1 on the positive electrode side of the battery 11 is connected to the terminal A1, and a ground line GL1 on the negative electrode side of the battery 11 is connected to the terminal A2.
  • the phrase "the configuration X1 and the configuration X2 are connected” means that the configuration X1 and the configuration X2 are wiring (line) such as a cable or a conductive pattern. ) is electrically connected.
  • the level of the ground line GL1 is assumed to be the ground level (hereinafter referred to as "GND level").
  • the power supply line PL1 corresponds to a "first power supply line”
  • the ground line GL1 corresponds to a "first ground line”.
  • the power supply circuit 30 is a step-down voltage regulator that steps down the voltage V1 (eg, 12 V) from the battery 11 to generate a predetermined voltage V2 (eg, 5 V).
  • V1 eg. 12 V
  • V2 e.g. 5 V
  • a wiring pattern extending from the terminal A1 and a wiring pattern P1 extending from the terminal A2 are connected to the power supply circuit 30 . Therefore, the voltage V1 is applied to the power supply circuit 30 with reference to the GND level.
  • a wiring pattern P1 is connected to the terminal A3, and an output node of the power supply circuit 30 is connected to the terminal A4 via the wiring pattern. Therefore, the power supply circuit 30 applies a predetermined voltage V2 to the terminal A4 as a GND level reference.
  • the microcomputer 31 is a circuit that controls the operation of the power supply circuit 30 . Although the details will be described later, the microcomputer 31 stops the operation of the power supply circuit 30 when, for example, disconnection or the like occurs in the ground line GL2 (described later) between the power supply board 20 and the LED board 21 .
  • the LED board 21 is a board on which an LED device 40 that is a light source of the headlamp, terminals B1 and B2, and a connector C1 are mounted.
  • a power line PL2 connected to the terminal A4 is connected to the terminal B1. Therefore, the voltage V2 is applied to the terminal B1 via the power supply line PL2.
  • a ground line GL2 connected to the terminal A3 is connected to the terminal B2. Therefore, the level of the terminal B2 becomes the same GND level as the levels of the ground line GL1 and the wiring pattern P1.
  • Power supply line PL2 corresponds to a "second power supply line”
  • ground line GL2 corresponds to a "second ground line”.
  • the LED device 40 is a light source that lights based on the voltage V2, and includes current sources CS1 to CSn, light emitting elements D1 to Dn, an adjustment section 50, and a detection section 51.
  • n is a value indicating the number of light emitting elements and current sources, and is 1000, for example. Therefore, the LED device 40 of this embodiment includes 1000 current sources CS and 1000 light emitting elements D.
  • Each of the current sources CS1 to CSn supplies constant currents I1 to In corresponding to the output of the adjusting section 50 (described later) to the light emitting elements D1 to Dn.
  • Each of the current sources CS1 to CSn of the present embodiment outputs currents I1 to In corresponding to the duty ratio of an input PWM (Pulse Width Modulation) signal having a predetermined period, for example.
  • the “duty ratio” is, for example, a value determined by a period of one cycle of the PWM signal and a period of high level in one cycle.
  • the current source CS1 stops generating the current I1 when the duty ratio of the input PWM signal is 0 (zero). Further, the current source CS1 increases the value of the generated current I1 when the duty ratio of the PWM signal increases.
  • the current source CS1 has been described here, the same applies to the current sources CS2 to CSn. Also, the current source CS1 is provided between the wiring pattern P2 connected to the terminal B1 and the light emitting element D1.
  • the current source CS1 may be provided not necessarily between the wiring pattern P2 and the light emitting element D1 but between the light emitting element D1 and the wiring pattern P3. That is, the current source CS1 may be connected to the cathode side of the light emitting element D1.
  • the light emitting element D1 is an element that emits light with a luminance corresponding to the current I1 from the current source CS1.
  • the anode of the light emitting element D1 is connected to the current source CS1, and the cathode is connected to the wiring pattern P3 connected to the terminal B2. Therefore, the current source CS1 and the light emitting element D1 are connected in series between the wiring pattern P2 to which the voltage V2 is applied and the wiring pattern P3 at the GND level.
  • the current sources CS2 to CSn and the light emitting elements D2 to Dn are connected between the wiring patterns P2 and P3 in the same manner as the current source CS1 and the light emitting element D1. Therefore, in the present embodiment, n (for example, 1000) serially connected current sources CS and light emitting elements D are connected in parallel between the wiring patterns P2 and P3. In this way, by connecting the series-connected current sources CS and the light emitting elements D in parallel between the wiring patterns P2 and P3, a large number (eg, 1000) of light emitting elements are connected to a low voltage V2 (eg, 5 V). can be driven based on
  • the adjustment unit 50 adjusts the currents I1 to In of the current sources CS1 to CSn based on instructions from the microcomputer 72, which will be described later. Specifically, for example, when the current I1 of the current source CS1 is a desired constant current, the adjustment unit 50 outputs a PWM signal having a duty ratio corresponding to the desired constant current to the current source CS1.
  • the detection unit 51 detects, for example, the temperature and forward voltage of each of the light emitting elements D1 to Dn. Specifically, the detection unit 51 acquires a signal from a temperature sensor (not shown) provided in close proximity to each of the light emitting elements D1 to Dn and a voltage across each of the light emitting elements D1 to Dn.
  • a temperature sensor not shown
  • the connector C1 is a component to which the cable 100 between the LED board 21 and the control board 22 is connected.
  • the cable 100 includes a communication line CL1 for transmitting information to the adjusting section 50, a communication line CL2 for transmitting information from the detecting section 51, and a ground line GL3.
  • the connector C1 connects the wiring from the adjustment unit 50 and the communication line CL1, and connects the wiring from the detection unit 51 and the communication line CL2. Further, the connector C1 connects the GND level wiring pattern P3 and the ground line GL3.
  • the communication lines CL1 and CL2 are illustrated as one wiring in FIG. 1 for convenience, they are not limited to this, and may include a plurality of wirings according to the communication standard. Further, the ground line GL3 of the present embodiment corresponds to the "third ground line" used when the cable 100 transmits various information.
  • the control board 22 is a board on which circuits for controlling the power supply circuit 30 and the LED devices 40 are mounted. Specifically, the control board 22 is mounted with a power supply circuit 70, a detection section 71, a microcomputer 72, and a connector C2, and has terminals E1 and E2.
  • a power line PL3 connected to the power line PL1 is connected to the terminal E1, and a ground line GL4 connected to the ground line GL1 is connected to the terminal A2.
  • a wiring pattern P4 functioning as GND (ground) of the control board 22 is connected to the terminal E2. Therefore, various circuits of the control board 22 operate using the battery 11 as a power source.
  • the power supply line PL3 is connected to the power supply line PL1, and the ground line GL4 is connected to the ground line GL1, but the present invention is not limited to this.
  • the power line PL3 may be connected to the positive electrode of the battery 11 together with the power line PL1
  • the ground line GL4 may be connected to the negative electrode of the battery 11 together with the ground line GL1.
  • the ground line GL4 corresponds to the "fourth ground line”.
  • the connector C2 is a component that connects the cable 100 and the wiring from the detection unit 71 and the microcomputer 72.
  • the connector C ⁇ b>2 connects the ground line GL ⁇ b>3 and the wiring from the detection unit 71 .
  • the GND level wiring pattern P3 on the LED substrate 21 and the detection section 71 are connected via the connector C1, the ground line GL3, and the connector C2.
  • the connector C2 connects the communication line CL1 and wiring for transmitting signals from the microcomputer 72, and connects the communication line CL2 and wiring for transmitting information to the microcomputer 72.
  • the adjustment section 50 and the microcomputer 72 are connected via the connector C1, the communication line CL1, and the connector C2.
  • the detection unit 51 and the microcomputer 72 are connected via the connector C1, the communication line CL2, and the connector C2.
  • the power supply circuit 70 is a circuit that generates a voltage V3 (eg, 5 V) for operating the detection section 71 and the microcomputer 72 based on the voltage V1 applied to the terminal E1.
  • V3 eg, 5 V
  • each of the power supply circuit 70, the detection section 71, and the microcomputer 72 mounted on the control board 22 is connected to the wiring pattern P4 that serves as the GND level of the control board 22.
  • the detection unit 71 is a circuit that detects the current flowing through the ground line GL3, and the microcomputer 72 controls the adjustment unit 50 based on a signal S1 from an external ECU (Electronic Control Unit) and the detection result of the detection unit 51. Control. Further, the microcomputer 72 transmits to the microcomputer 31 a signal for stopping the power supply circuit 30 based on the detection result of the detection unit 71 .
  • ECU Electronic Control Unit
  • FIG. 2 is a diagram showing an embodiment of the detection unit 71 and the microcomputer 72.
  • FIG. 2 since the detection unit 71 and the microcomputer 72a are mainly drawn, the power supply circuit 70 and the like are omitted as appropriate.
  • 2 and FIG. 1 have the same blocks (circuits, terminals, etc.) denoted by the same reference numerals, and detailed description thereof will be omitted.
  • the detection unit 71 includes a resistor 200 that detects the current flowing through the ground line GL3, and an amplifier circuit 201 that amplifies and outputs the voltage across the resistor 200.
  • the resistor 200 is mounted between a terminal (not shown) of the connector C2 connected to the ground line GL3 and a wiring pattern P4 formed on the control board 22. FIG. That is, one end of the resistor 200 is connected to the ground line GL3, and the other end is connected to the wiring pattern P4. Therefore, the current flowing through the ground line GL3 flows to the negative electrode of the battery 11 via the resistor 200 connected in series with the ground line GL3, the wiring pattern P4, the terminal E2, and the ground line GL4.
  • FIG. 2 outlines not only the connection relationship of the resistor 200, the amplifier circuit 201, the microcomputer 72a, and the connector C2 on the control board 22, but also the mounted positions on the control board 22.
  • the resistor 200 is provided in the immediate vicinity of the connector C2, and the amplifier circuit 201 and the microcomputer 72a are provided at a position away from the connector C2. That is, the resistor 200 is arranged between the connector C2 and the microcomputer 72a.
  • the microcomputer 72a includes a CPU and memory (not shown).
  • the CPU of the microcomputer 72a implements various functional blocks in the microcomputer 72a by executing programs stored in the memory. Specifically, a determination unit 300 and a control unit 301 are implemented in the microcomputer 72a.
  • the determination unit 300 determines whether the ground line GL2 has entered a high impedance state. Specifically, when the current flowing through the resistor 200 reaches or exceeds a predetermined value Th (for example, a value (150 mA) that is 50% higher than the current value (100 mA) during normal operation), the determination unit 300 determines that the ground line GL2 is in a high impedance state. It is determined that a predetermined value Th (for example, a value (150 mA) that is 50% higher than the current value (100 mA) during normal operation).
  • Th for example, a value (150 mA) that is 50% higher than the current value (100 mA) during normal operation
  • the ground line GL2 is in a high-impedance state refers to a state in which the impedance of the ground line GL2 itself is increased due to age-related deterioration or disconnection of the ground line GL2, the ground line GL2, the terminals A3 and B2, and a state in which the connection between the terminals A3 and B2 has deteriorated and the impedance between the terminals A3 and B2 has increased. Details of current paths and the like in the vehicle lamp 10 when the ground line GL2 is in a high impedance state will be described later.
  • the control unit 301 controls the adjustment unit 50 based on a signal S1 that is output from an ECU (not shown) and indicates the lighting conditions of the light emitting elements D1 to Dn and detection results such as the temperatures of the light emitting elements D1 to Dn.
  • a signal is output to the communication line CL1.
  • the “lighting condition of the light emitting element D” is a condition including, for example, whether or not the light emitting element D is to be lit, and luminance (current to be passed to the light emitting element D) when the light emitting element D is to be lit.
  • the control unit 301 generates a signal for controlling the adjustment unit 50 so that the brightness determined by the lighting conditions is lowered. That is, the control unit 301 performs so-called temperature derating control on the light emitting elements D1 to Dn.
  • the control unit 301 controls the microcomputer 31 shown in FIG. 30 outputs a signal to stop the operation.
  • a cable 101 including a communication line and a ground line is connected between the microcomputer 31 and the microcomputer 72 shown in FIG.
  • the power supply circuit 30 applies the voltage V2 to the terminal A4 and outputs from the terminal A4 a current Is1 that is the sum of the currents I1 to In flowing through the light emitting elements D1 to Dn as loads.
  • Current Is1 flows to wiring pattern P2 via terminal A4, power supply line PL2, terminal B1, and light emitting elements D1 to Dn.
  • the ground line GL2 connected to the power supply substrate 20 and the ground line GL3 included in the cable 100 are connected to the wiring pattern P2, and the ground line GL2 is sufficiently thicker than the ground line GL3. . That is, the thickness of each line is adjusted so that the impedance of the ground line GL2 is sufficiently smaller than the impedance of the ground line GL3. Therefore, in this embodiment, almost all of the current Is1 that is output from the power supply circuit 30 and flows into the wiring pattern P2 flows to the power supply board 20 via the terminal B2, the ground line GL2, and the terminal A3.
  • the value of the current flowing from the wiring pattern P2 of the LED board 21 to the control board 22 via the ground line GL3 is very small. Therefore, since the current flowing through the resistor 200 of the detection unit 71 shown in FIG. 2 is also small, the determination unit 300 of the microcomputer 72a determines that the current flowing through the resistor 200 is equal to or greater than the predetermined value Th (the ground line GL2 is in the high impedance state). ). As a result, the light-emitting elements D1 to Dn of the LED device 40 are lit under conditions corresponding to the signal S1 and the detection result of the detection section 51.
  • FIG. 4 shows only main blocks for explaining the current path Y2 (chain line). Further, parts, circuits, and the like denoted by the same reference numerals in FIG. 4 and FIG. 1 are the same.
  • the power supply circuit 30 applies the voltage V2 to the terminal A4 and outputs from the terminal A4 a current Is2 that is the sum of the currents I1 to In flowing through the light emitting elements D1 to Dn as loads.
  • Current Is1 flows to wiring pattern P2 via terminal A4, power supply line PL2, terminal B1, and light emitting elements D1 to Dn.
  • the ground line GL2 connecting between the terminals A3 and B2 is disconnected.
  • the current Is2 flowing through the wiring pattern P2 flows through the connector C1 to the ground line GL3.
  • the current Is2 flowing to the ground line GL3 flows from the connector C2 to which the ground line GL3 is connected to the resistor 200 and the wiring pattern P4 in the detection section 71 in FIG.
  • the current Is2 flows from the wiring pattern P4 to the negative electrode of the battery 11 via the terminal E2, the ground line GL4, and the ground line Gl1.
  • the control unit 301 of the microcomputer 72 a outputs a signal for stopping the operation of the power supply circuit 30 to the microcomputer 31 via the cable 101 based on the determination result of the determination unit 300 .
  • the microcomputer 31 stops the operation of the power supply circuit 30 .
  • the generation of the voltage V2 is also stopped. Therefore, the current flowing from the LED device 40 to the ground line GL3 is also sufficiently small (substantially zero).
  • the cable 100 used for exchanging information can be appropriately protected from a large current.
  • FIG. 5 is a diagram showing an embodiment in which the determination section 300 of the microcomputer 72a shown in FIG. 5, the power supply circuit 70 and the like are omitted as appropriate, and blocks (circuits, terminals, etc.) denoted by the same reference numerals as in FIGS. 1 and 2 are the same.
  • a comparator 75 compares the output of the amplifier circuit 201 with the reference voltage Vref to determine whether the ground line GL2 has entered a high impedance state.
  • the level of the reference voltage Vref is set to the level of the output of the amplifier circuit 201 when the current flowing through the resistor 200 reaches a predetermined value Th. Therefore, when the output of the amplifier circuit 201 becomes higher than the reference voltage Vref, the comparator 75 determines that the current flowing through the resistor 200 is higher than the predetermined value Th. That is, the comparator 75 operates as a "determining unit" that determines that the ground line GL2 is in the high impedance state when the output of the amplifier circuit 201 becomes higher than the reference voltage Vref.
  • the control unit 301 described above is implemented in the microcomputer 72b.
  • the control unit 301 transmits a predetermined signal to the microcomputer 31 to stop the operation of the power supply circuit 30 .
  • the comparator 75 and the microcomputer 72b shown in FIG. 5 are used, it is possible to prevent a large current from flowing through the ground line GL3.
  • the lamp shown in FIG. 1 is the vehicle lamp 10, it is not limited to this.
  • the lamp shown in FIG. 1 may be used as a street lamp or a general lighting fixture.
  • the microcomputer 72a can determine whether the ground line GL2 between the power supply substrate 20 and the LED substrate 21 is in the high impedance state.
  • the microcomputer 72 may have a detection section that detects the current flowing through the ground line GL3 as the voltage across the resistor 200. FIG. Even in such a case, the state of the ground line GL2 can be grasped as in the present embodiment.
  • the resistor 200 in the detection unit 71 is connected between the terminal (not shown) of the connector C2 and the wiring pattern P4 so as to detect the current flowing through the ground line GL3, but the present invention is not limited to this.
  • the resistor 200 may be connected between the wiring pattern P4 and the terminal E2 so as to detect the current flowing through the ground line GL4. Even when resistor 200 is arranged at such a position, it is possible to detect whether or not ground line GL2 is in the high impedance state.
  • the detection unit 71 detects the current flowing through the ground line GL3, and the determination unit 300 determines whether or not the ground line GL2 is in a high impedance state based on the detection result of the detection unit 71. can. Therefore, in the vehicle lamp 10, disconnection or the like of the ground line GL2 can be detected even when the power supply circuit 30, which is a voltage regulator, is used.
  • the communication line CL1 connecting the adjustment unit 50 and the control unit 301 since the communication line CL1 connecting the adjustment unit 50 and the control unit 301 is used, the light emission conditions of the LED device 40 can be adjusted.
  • the resistor 200 is connected in series to the ground line GL3, and the detection section 71 detects the current flowing through the ground line GL3. Therefore, an abnormality in the ground line GL2 can be detected with high accuracy, for example, compared to a configuration that detects the current flowing through the ground line GL4.
  • the resistor 200 is mounted in the immediate vicinity of the connector C2 on the control board 22, for example, as shown in FIG. Therefore, the power consumed by resistor 200 can be reduced.
  • the ground line GL2 is thicker than the ground line GL3, the current value flowing through the ground line GL3 can be reduced when the ground line GL2 is normal.
  • control unit 301 stops the operation of the power supply circuit 30 when the ground line GL2 is in a high impedance state. Therefore, it is possible to prevent a large current from flowing through the ground line GL3.
  • the LED device 40 (light source) is applied to headlights, but may be applied to street lights, for example. Even in such a case, effects similar to those of the present embodiment can be obtained.
  • Vehicle lamp 11 Battery 20 Power supply board 21 LED board 22 Control boards 30, 70 Power supply circuits 31, 72 Microcomputer 40 LED device 50 Adjustment units 51, 71 Detection unit 75 Comparators 100, 101 Cable 200 Resistor 201 Amplifier circuits CS1 to CSn Current Sources D1 to Dn Light emitting elements A1 to A4, B1, B2, E1, E2 Terminals C1, C2 Connectors PL1 to PL3 Power supply lines GL1 to GL4 Ground lines CL1, CL2 Communication lines P1 to P4 Wiring patterns

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

Provided is a lamp comprising: a voltage regulator (30) to which a first power supply line (PL1) to which a first voltage of a voltage source is applied, and a first ground line (GL1) are connected, and which applies a second voltage to a second power supply line (PL2); a light source (40) to which the second power supply line (PL2), and a second ground line (GL2) connected to the first ground line (GL1) are connected; a control unit to which a third ground line (GL3) connected to the second ground line (GL2), a fourth ground line (GL4) connected to the first ground line (GL1), and communication lines (CL1, CL2) from the light source (40) are connected, and which controls the light source (40); a detection unit (71) which detects an electric current flowing through the third ground line (GL3) or the fourth ground line (GL4); and a determination unit which, on the basis of a detection result from the detection unit (71), determines whether the second ground line (GL2) is brought into a high-impedance state or not.

Description

灯具lamp
　本開示は、灯具に関する。 This disclosure relates to lighting fixtures.
　所定の電流を供給する電流レギュレータを用いて、直列接続された複数の発光素子を含む光源を点灯させる灯具がある（例えば、特許文献１）。 There is a lamp that uses a current regulator that supplies a predetermined current to light a light source that includes a plurality of light emitting elements connected in series (for example, Patent Document 1).
日本国特開２０２０－９５８１６号公報Japanese Patent Application Laid-Open No. 2020-95816
　ところで、電流レギュレータを用いて光源を点灯させる際に、例えば、光源が接続された接地ラインが断線すると、一般に電流レギュレータの出力電圧は大きく上昇する。このため、電流レギュレータの出力電圧を計測することにより、接地ラインのインピーダンスの増加を検出することができる。 By the way, when the light source is turned on using the current regulator, for example, if the ground line to which the light source is connected is broken, the output voltage of the current regulator generally rises significantly. Therefore, by measuring the output voltage of the current regulator, an increase in the impedance of the ground line can be detected.
　しかしながら、発光素子を含む光源に対し、所定の電圧を印加する電圧レギュレータを用いた場合、仮に光源が接続された接地ラインのインピーダンスが増加しても、電圧レギュレータは所定の電圧を出力し続ける。したがって、電圧レギュレータを用いる灯具において、光源が接続された接地ラインの断線等を検出することは難しいという問題がある。 However, when using a voltage regulator that applies a predetermined voltage to a light source that includes a light emitting element, the voltage regulator continues to output a predetermined voltage even if the impedance of the ground line to which the light source is connected increases. Therefore, in a lamp using a voltage regulator, it is difficult to detect disconnection or the like of the ground line to which the light source is connected.
　本開示は、上記のような従来の問題に鑑みてなされたものであって、その目的は、電圧レギュレータを用いつつ、接地ラインのインピーダンスの増加を検出することができる灯具を提供することにある。 The present disclosure has been made in view of the conventional problems as described above, and an object thereof is to provide a lamp that can detect an increase in impedance of a ground line while using a voltage regulator. .
　前述した課題を解決する主たる本開示は、電圧源の第１電圧が印加される第１電源ラインと、第１接地ラインとが接続され、第２電圧を第２電源ラインに印加する電圧レギュレータと、前記第２電源ラインと、前記第１接地ラインに接続された第２接地ラインとが接続された光源と、前記第２接地ラインに接続された第３接地ラインと、前記第１接地ラインに接続された第４接地ラインと、前記光源からの通信ラインとが接続され、前記光源を制御する制御部と、前記第３接地ライン、または前記第４接地ラインに流れる電流を検出する検出部と、前記検出部の検出結果に基づいて、前記第２接地ラインがハイインピーダンス状態になったか否かを判定する判定部と、を備える灯具である。 The main disclosure for solving the above-mentioned problems is a voltage regulator connected to a first power supply line to which a first voltage of a voltage source is applied and a first ground line and applying a second voltage to the second power supply line. , a light source connected to the second power supply line and a second ground line connected to the first ground line; a third ground line connected to the second ground line; a connected fourth ground line and a communication line from the light source are connected, a controller for controlling the light source, and a detector for detecting a current flowing through the third ground line or the fourth ground line; and a determination unit that determines whether or not the second ground line is in a high impedance state based on the detection result of the detection unit.
　本開示によれば、電圧レギュレータを用いつつ、接地ラインのインピーダンスの増加を検出することができる灯具を提供することができる。 According to the present disclosure, it is possible to provide a lamp that can detect an increase in the impedance of the ground line while using a voltage regulator.
車両用灯具１０の一例を示す図である。1 is a diagram showing an example of a vehicle lamp 10; FIG. 検出部７１及びマイコン７２の一例を示す図である。7 is a diagram showing an example of a detection unit 71 and a microcomputer 72; FIG. 電流経路Ｙ１を説明するための図である。FIG. 4 is a diagram for explaining a current path Y1; FIG. 電流経路Ｙ２を説明するための図である。It is a figure for demonstrating current path Y2. コンパレータ７５が実装された制御基板２２の一例を示す図である。4 is a diagram showing an example of a control board 22 on which a comparator 75 is mounted; FIG.
　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.
＝＝＝＝＝本実施形態＝＝＝＝＝
＜＜＜車両用灯具１０の構成＞＞＞
　図１は、本開示の一実施形態である車両用灯具１０の構成の一例を示す図である。車両用灯具１０は、例えば、車両用のバッテリー１１の電圧Ｖ１に基づいて、点灯する光源を含むヘッドランプである。車両用灯具１０は、電源基板２０、ＬＥＤ（Light Emitting Diode）基板２１、及び制御基板２２を含んで構成される。 =====This Embodiment=====
<<<Configuration of vehicle lamp 10>>>
FIG. 1 is a diagram showing an example configuration of a vehicle lamp 10 that is an embodiment of the present disclosure. The vehicle lamp 10 is, for example, a headlamp including a light source that is lit based on the voltage V1 of the vehicle battery 11 . The vehicle lamp 10 includes a power supply board 20 , an LED (Light Emitting Diode) board 21 , and a control board 22 .
＜＜電源基板２０＞＞
　電源基板２０は、電圧Ｖ１に基づいて、光源に印加する所定の電圧Ｖ２を生成する電源回路３０と、マイコン３１とが実装された樹脂製の基板（ＰＣＢ：Printed Circuit Board）であり、端子Ａ１～Ａ４を含む。なお、以下、本実施形態において、「基板」とは、特段断らない限り、例えば、銅等の導電性の配線パターンが形成されているＰＣＢ基板であることとする。また、バッテリー１１の電圧Ｖ１は「第１電圧」に相当し、所定の電圧Ｖ２は「第２電圧」に相当する。 <<Power supply board 20>>
The power supply board 20 is a resin board (PCB: Printed Circuit Board) on which a power supply circuit 30 that generates a predetermined voltage V2 to be applied to the light source based on the voltage V1 and a microcomputer 31 are mounted. Including ~A4. In the present embodiment, hereinafter, the term "substrate" means, for example, a PCB substrate on which a conductive wiring pattern made of copper or the like is formed, unless otherwise specified. Also, the voltage V1 of the battery 11 corresponds to the "first voltage", and the predetermined voltage V2 corresponds to the "second voltage".
　端子Ａ１には、バッテリー１１の正極側の電源ラインＰＬ１が接続され、端子Ａ２には、バッテリー１１の負極側の接地ラインＧＬ１が接続されている。以下、本実施形態では、「構成Ｘ１と、構成Ｘ２と、が接続されている」とは、特段断らない限り、構成Ｘ１と、構成Ｘ２とが、ケーブルや導電性のパターン等の配線（ライン）により電気的に接続されていることをいう。また、本実施形態では、接地ラインＧＬ１のレベルを、グランドレベル（以下、「ＧＮＤレベル」と称する。）とする。なお、電源ラインＰＬ１は、「第１電源ライン」に相当し、接地ラインＧＬ１は、「第１接地ライン」に相当する。 A power supply line PL1 on the positive electrode side of the battery 11 is connected to the terminal A1, and a ground line GL1 on the negative electrode side of the battery 11 is connected to the terminal A2. Hereinafter, in the present embodiment, unless otherwise specified, the phrase "the configuration X1 and the configuration X2 are connected" means that the configuration X1 and the configuration X2 are wiring (line) such as a cable or a conductive pattern. ) is electrically connected. Further, in this embodiment, the level of the ground line GL1 is assumed to be the ground level (hereinafter referred to as "GND level"). The power supply line PL1 corresponds to a "first power supply line", and the ground line GL1 corresponds to a "first ground line".
　電源回路３０は、バッテリー１１からの電圧Ｖ１（例えば、１２Ｖ）を降圧し、所定の電圧Ｖ２（例えば、５Ｖ）を生成する降圧型の電圧レギュレータである。電源回路３０には、端子Ａ１から延びる配線パターンと、端子Ａ２から延びる配線パターンＰ１と、が接続されている。このため、電源回路３０には、ＧＮＤレベルを基準として、電圧Ｖ１が印加されることになる。また、端子Ａ３には、配線パターンＰ１が接続され、端子Ａ４には、電源回路３０の出力ノードが配線パターンを介して接続される。このため、電源回路３０は、ＧＮＤレベル基準として、端子Ａ４に所定の電圧Ｖ２を印加することになる。 The power supply circuit 30 is a step-down voltage regulator that steps down the voltage V1 (eg, 12 V) from the battery 11 to generate a predetermined voltage V2 (eg, 5 V). A wiring pattern extending from the terminal A1 and a wiring pattern P1 extending from the terminal A2 are connected to the power supply circuit 30 . Therefore, the voltage V1 is applied to the power supply circuit 30 with reference to the GND level. A wiring pattern P1 is connected to the terminal A3, and an output node of the power supply circuit 30 is connected to the terminal A4 via the wiring pattern. Therefore, the power supply circuit 30 applies a predetermined voltage V2 to the terminal A4 as a GND level reference.
　マイコン３１は、電源回路３０の動作を制御する回路である。詳細は後述するが、マイコン３１は、例えば、電源基板２０と、ＬＥＤ基板２１との間の接地ラインＧＬ２（後述）に断線等が生じると、電源回路３０の動作を停止させる。 The microcomputer 31 is a circuit that controls the operation of the power supply circuit 30 . Although the details will be described later, the microcomputer 31 stops the operation of the power supply circuit 30 when, for example, disconnection or the like occurs in the ground line GL2 (described later) between the power supply board 20 and the LED board 21 .
＜＜ＬＥＤ基板２１＞＞
　ＬＥＤ基板２１は、ヘッドランプの光源であるＬＥＤデバイス４０と、端子Ｂ１，Ｂ２、及びコネクタＣ１が実装された基板である。端子Ｂ１には、端子Ａ４に接続された電源ラインＰＬ２が接続されている。このため、端子Ｂ１には、電源ラインＰＬ２を介して電圧Ｖ２が印加される。また、端子Ｂ２には、端子Ａ３に接続された接地ラインＧＬ２が接続されている。このため、端子Ｂ２のレベルは、接地ラインＧＬ１及び配線パターンＰ１のレベルと同じＧＮＤレベルとなる。なお、電源ラインＰＬ２は、「第２電源ライン」に相当し、接地ラインＧＬ２は、「第２接地ライン」に相当する。 << LED board 21 >>
The LED board 21 is a board on which an LED device 40 that is a light source of the headlamp, terminals B1 and B2, and a connector C1 are mounted. A power line PL2 connected to the terminal A4 is connected to the terminal B1. Therefore, the voltage V2 is applied to the terminal B1 via the power supply line PL2. A ground line GL2 connected to the terminal A3 is connected to the terminal B2. Therefore, the level of the terminal B2 becomes the same GND level as the levels of the ground line GL1 and the wiring pattern P1. Power supply line PL2 corresponds to a "second power supply line", and ground line GL2 corresponds to a "second ground line".
　ＬＥＤデバイス４０は、電圧Ｖ２に基づいて点灯する光源であり、電流源ＣＳ１～ＣＳｎ、発光素子Ｄ１～Ｄｎ、調整部５０、及び検出部５１を含んで構成される。なお、ここで「ｎ」は、発光素子、及び電流源の個数を示す値であり、例えば１０００である。したがって、本実施形態のＬＥＤデバイス４０には、１０００個の電流源ＣＳと、１０００個の発光素子Ｄとが含まれている。なお、本実施形態では、ｎは、１０００であることとしたが、１以上の整数であれば良い。 The LED device 40 is a light source that lights based on the voltage V2, and includes current sources CS1 to CSn, light emitting elements D1 to Dn, an adjustment section 50, and a detection section 51. Here, “n” is a value indicating the number of light emitting elements and current sources, and is 1000, for example. Therefore, the LED device 40 of this embodiment includes 1000 current sources CS and 1000 light emitting elements D. FIG. In this embodiment, n is set to 1000, but may be an integer of 1 or more.
　電流源ＣＳ１～ＣＳｎのそれぞれは、調整部５０（後述）の出力に応じた一定の電流Ｉ１～Ｉｎを発光素子Ｄ１～Ｄｎに供給する。本実施形態の電流源ＣＳ１～ＣＳｎのそれぞれは、例えば、入力される所定周期のＰＷＭ（Pulse Width Modulation）信号のデューティ比に応じた電流Ｉ１～Ｉｎを出力する。なお、ここでは、「デューティ比」とは、例えば、ＰＷＭ信号の１周期の期間と、１周期においてハイレベルとなる期間と、で定まる値である。 Each of the current sources CS1 to CSn supplies constant currents I1 to In corresponding to the output of the adjusting section 50 (described later) to the light emitting elements D1 to Dn. Each of the current sources CS1 to CSn of the present embodiment outputs currents I1 to In corresponding to the duty ratio of an input PWM (Pulse Width Modulation) signal having a predetermined period, for example. Here, the “duty ratio” is, for example, a value determined by a period of one cycle of the PWM signal and a period of high level in one cycle.
　電流源ＣＳ１は、入力されるＰＷＭ信号のデューティ比が０（ゼロ）の場合、電流Ｉ１の生成を停止する。また、電流源ＣＳ１は、ＰＷＭ信号のデューティ比が高くなると、生成する電流Ｉ１の値を増加させる。なお、ここでは、電流源ＣＳ１について説明したが、電流源ＣＳ２～ＣＳｎについても同様である。また、電流源ＣＳ１は、端子Ｂ１に接続された配線パターンＰ２と、発光素子Ｄ１との間に設けられる。なお、電流源ＣＳ１は、必ずしも配線パターンＰ２と、発光素子Ｄ１との間ではなく、発光素子Ｄ１と、配線パターンＰ３との間に設けられていても良い。つまり、電流源ＣＳ１は、発光素子Ｄ１のカソード側に接続されていても良い。 The current source CS1 stops generating the current I1 when the duty ratio of the input PWM signal is 0 (zero). Further, the current source CS1 increases the value of the generated current I1 when the duty ratio of the PWM signal increases. Although the current source CS1 has been described here, the same applies to the current sources CS2 to CSn. Also, the current source CS1 is provided between the wiring pattern P2 connected to the terminal B1 and the light emitting element D1. The current source CS1 may be provided not necessarily between the wiring pattern P2 and the light emitting element D1 but between the light emitting element D1 and the wiring pattern P3. That is, the current source CS1 may be connected to the cathode side of the light emitting element D1.
　発光素子Ｄ１は、電流源ＣＳ１からの電流Ｉ１に応じた輝度で発光する素子である。発光素子Ｄ１のアノードは、電流源ＣＳ１に接続され、カソードは、端子Ｂ２に接続された配線パターンＰ３に接続される。このため、電圧Ｖ２が印加された配線パターンＰ２と、ＧＮＤレベルの配線パターンＰ３との間には、電流源ＣＳ１及び発光素子Ｄ１が直列に接続されることになる。 The light emitting element D1 is an element that emits light with a luminance corresponding to the current I1 from the current source CS1. The anode of the light emitting element D1 is connected to the current source CS1, and the cathode is connected to the wiring pattern P3 connected to the terminal B2. Therefore, the current source CS1 and the light emitting element D1 are connected in series between the wiring pattern P2 to which the voltage V2 is applied and the wiring pattern P3 at the GND level.
　また、電流源ＣＳ２～ＣＳｎ、及び発光素子Ｄ２～Ｄｎは、配線パターンＰ２，Ｐ３の間に、電流源ＣＳ１、及び発光素子Ｄ１と同様に接続されている。このため、本実施形態では、配線パターンＰ２，Ｐ３の間には、直列接続された電流源ＣＳ及び発光素子Ｄが、ｎ個（例えば、１０００個）並列に接続されることになる。このように、配線パターンＰ２，Ｐ３の間に、直列接続された電流源ＣＳ及び発光素子Ｄを並列接続することにより、多数（例えば、１０００個）の発光素子を低い電圧Ｖ２（例えば、５Ｖ）に基づいて駆動することができる。 Also, the current sources CS2 to CSn and the light emitting elements D2 to Dn are connected between the wiring patterns P2 and P3 in the same manner as the current source CS1 and the light emitting element D1. Therefore, in the present embodiment, n (for example, 1000) serially connected current sources CS and light emitting elements D are connected in parallel between the wiring patterns P2 and P3. In this way, by connecting the series-connected current sources CS and the light emitting elements D in parallel between the wiring patterns P2 and P3, a large number (eg, 1000) of light emitting elements are connected to a low voltage V2 (eg, 5 V). can be driven based on
　調整部５０は、後述するマイコン７２からの指示に基づいて、電流源ＣＳ１～ＣＳｎの電流Ｉ１～Ｉｎを調整する。具体的には、調整部５０は、例えば電流源ＣＳ１の電流Ｉ１を所望の定電流とする場合、電流源ＣＳ１に対し、所望の定電流に対応するデューティ比のＰＷＭ信号を出力する。 The adjustment unit 50 adjusts the currents I1 to In of the current sources CS1 to CSn based on instructions from the microcomputer 72, which will be described later. Specifically, for example, when the current I1 of the current source CS1 is a desired constant current, the adjustment unit 50 outputs a PWM signal having a duty ratio corresponding to the desired constant current to the current source CS1.
　検出部５１は、例えば、発光素子Ｄ１～Ｄｎのそれぞれの温度、順方向電圧を検出する。具体的には、検出部５１は、発光素子Ｄ１～Ｄｎのそれぞれの直近に設けられた温度センサ（不図示）からの信号と、発光素子Ｄ１～Ｄｎのそれぞれの両端電圧を取得する。 The detection unit 51 detects, for example, the temperature and forward voltage of each of the light emitting elements D1 to Dn. Specifically, the detection unit 51 acquires a signal from a temperature sensor (not shown) provided in close proximity to each of the light emitting elements D1 to Dn and a voltage across each of the light emitting elements D1 to Dn.
　コネクタＣ１は、ＬＥＤ基板２１と、制御基板２２との間のケーブル１００が接続される部品である。ケーブル１００は、調整部５０への情報を伝送する通信ラインＣＬ１、検出部５１からの情報を伝送する通信ラインＣＬ２、及び接地ラインＧＬ３を含む。ここで、コネクタＣ１は、調整部５０からの配線と、通信ラインＣＬ１とを接続するとともに、検出部５１からの配線と、通信ラインＣＬ２とを接続する。さらに、コネクタＣ１は、ＧＮＤレベルの配線パターンＰ３と、接地ラインＧＬ３とを接続する。 The connector C1 is a component to which the cable 100 between the LED board 21 and the control board 22 is connected. The cable 100 includes a communication line CL1 for transmitting information to the adjusting section 50, a communication line CL2 for transmitting information from the detecting section 51, and a ground line GL3. Here, the connector C1 connects the wiring from the adjustment unit 50 and the communication line CL1, and connects the wiring from the detection unit 51 and the communication line CL2. Further, the connector C1 connects the GND level wiring pattern P3 and the ground line GL3.
　なお、通信ラインＣＬ１，ＣＬ２は、例えば図１において、便宜上、１本の配線として記載しているが、これに限られず、通信規格に応じて複数の配線を含んでいても良い。また、本実施形態の接地ラインＧＬ３は、ケーブル１００が各種情報を伝送する際に用いられる「第３接地ライン」に相当する。 Although the communication lines CL1 and CL2 are illustrated as one wiring in FIG. 1 for convenience, they are not limited to this, and may include a plurality of wirings according to the communication standard. Further, the ground line GL3 of the present embodiment corresponds to the "third ground line" used when the cable 100 transmits various information.
＜＜制御基板２２＞＞
　制御基板２２は、電源回路３０やＬＥＤデバイス４０を制御するための回路が実装された基板である。具体的には、制御基板２２には、電源回路７０、検出部７１、マイコン７２、及びコネクタＣ２が実装されるとともに、制御基板２２は、端子Ｅ１，Ｅ２を有する。 <<control board 22>>
The control board 22 is a board on which circuits for controlling the power supply circuit 30 and the LED devices 40 are mounted. Specifically, the control board 22 is mounted with a power supply circuit 70, a detection section 71, a microcomputer 72, and a connector C2, and has terminals E1 and E2.
　端子Ｅ１には、電源ラインＰＬ１に接続された電源ラインＰＬ３が接続され、端子Ａ２には、接地ラインＧＬ１に接続された接地ラインＧＬ４が接続されている。また、端子Ｅ２には、制御基板２２のＧＮＤ（グランド）として機能する配線パターンＰ４が接続されている。このため、制御基板２２の各種回路は、バッテリー１１を電源として動作する。 A power line PL3 connected to the power line PL1 is connected to the terminal E1, and a ground line GL4 connected to the ground line GL1 is connected to the terminal A2. A wiring pattern P4 functioning as GND (ground) of the control board 22 is connected to the terminal E2. Therefore, various circuits of the control board 22 operate using the battery 11 as a power source.
　なお、本実施形態では、電源ラインＰＬ３は、電源ラインＰＬ１に接続され、接地ラインＧＬ４は、接地ラインＧＬ１に接続されることとしたが、これに限られない。例えば、電源ラインＰＬ３は、バッテリー１１の正極に、電源ラインＰＬ１とともに接続され、接地ラインＧＬ４は、バッテリー１１の負極に、接地ラインＧＬ１とともに接続されても良いい。なお、接地ラインＧＬ４は、「第４接地ライン」に相当する。 In this embodiment, the power supply line PL3 is connected to the power supply line PL1, and the ground line GL4 is connected to the ground line GL1, but the present invention is not limited to this. For example, the power line PL3 may be connected to the positive electrode of the battery 11 together with the power line PL1, and the ground line GL4 may be connected to the negative electrode of the battery 11 together with the ground line GL1. Note that the ground line GL4 corresponds to the "fourth ground line".
　コネクタＣ２は、ケーブル１００と、検出部７１及びマイコン７２からの配線を接続する部品である。ここで、コネクタＣ２は、接地ラインＧＬ３と、検出部７１からの配線とを接続する。この結果、ＬＥＤ基板２１におけるＧＮＤレベルの配線パターンＰ３と、検出部７１とは、コネクタＣ１、接地ラインＧＬ３、及びコネクタＣ２を介して接続されることになる。 The connector C2 is a component that connects the cable 100 and the wiring from the detection unit 71 and the microcomputer 72. Here, the connector C<b>2 connects the ground line GL<b>3 and the wiring from the detection unit 71 . As a result, the GND level wiring pattern P3 on the LED substrate 21 and the detection section 71 are connected via the connector C1, the ground line GL3, and the connector C2.
　また、コネクタＣ２は、通信ラインＣＬ１と、マイコン７２からの信号が伝送される配線とを接続するとともに、通信ラインＣＬ２と、マイコン７２へ情報を伝送するための配線とを接続する。この結果、調整部５０と、マイコン７２とは、コネクタＣ１、通信ラインＣＬ１、及びコネクタＣ２を介して接続されることになる。また、検出部５１と、マイコン７２とは、コネクタＣ１、通信ラインＣＬ２、及びコネクタＣ２を介して接続されることになる。 In addition, the connector C2 connects the communication line CL1 and wiring for transmitting signals from the microcomputer 72, and connects the communication line CL2 and wiring for transmitting information to the microcomputer 72. As a result, the adjustment section 50 and the microcomputer 72 are connected via the connector C1, the communication line CL1, and the connector C2. Also, the detection unit 51 and the microcomputer 72 are connected via the connector C1, the communication line CL2, and the connector C2.
　電源回路７０は、端子Ｅ１に印加された電圧Ｖ１に基づいて、検出部７１、及びマイコン７２を動作させるための電圧Ｖ３（例えば、５Ｖ）を生成する回路である。なお、本実施形態では、制御基板２２に実装された電源回路７０、検出部７１、及びマイコン７２のそれぞれは、制御基板２２のＧＮＤレベルとなる配線パターンＰ４が接続されている。 The power supply circuit 70 is a circuit that generates a voltage V3 (eg, 5 V) for operating the detection section 71 and the microcomputer 72 based on the voltage V1 applied to the terminal E1. In this embodiment, each of the power supply circuit 70, the detection section 71, and the microcomputer 72 mounted on the control board 22 is connected to the wiring pattern P4 that serves as the GND level of the control board 22. FIG.
　検出部７１は、接地ラインＧＬ３に流れる電流を検出する回路であり、マイコン７２は、外部のＥＣＵ（Electronic Control Unit）からの信号Ｓ１、及び検出部５１の検出結果に基づいて、調整部５０を制御する。また、マイコン７２は、検出部７１の検出結果に基づいて、電源回路３０を停止させる信号をマイコン３１に対して送信する。 The detection unit 71 is a circuit that detects the current flowing through the ground line GL3, and the microcomputer 72 controls the adjustment unit 50 based on a signal S1 from an external ECU (Electronic Control Unit) and the detection result of the detection unit 51. Control. Further, the microcomputer 72 transmits to the microcomputer 31 a signal for stopping the power supply circuit 30 based on the detection result of the detection unit 71 .
　図２は、検出部７１、及びマイコン７２の一実施形態を示す図である。なお、図２においては、検出部７１、及びマイコン７２ａを中心に描いているため、電源回路７０等は適宜省略している。また、図２と、図１とで、同じ符号が付されたブロック（回路、端子等）は、同じであるため、詳細な説明は省略する。 FIG. 2 is a diagram showing an embodiment of the detection unit 71 and the microcomputer 72. FIG. In addition, in FIG. 2, since the detection unit 71 and the microcomputer 72a are mainly drawn, the power supply circuit 70 and the like are omitted as appropriate. 2 and FIG. 1 have the same blocks (circuits, terminals, etc.) denoted by the same reference numerals, and detailed description thereof will be omitted.
　検出部７１は、接地ラインＧＬ３に流れる電流を検出する抵抗２００と、抵抗２００の両端の電圧を増幅して出力する増幅回路２０１と、を含んで構成される。抵抗２００は、接地ラインＧＬ３が接続されたコネクタＣ２の端子（不図示）と、制御基板２２に形成された配線パターンＰ４との間に実装されている。つまり、抵抗２００の一端は、接地ラインＧＬ３に接続され、他端は、配線パターンＰ４に接続されている。このため、接地ラインＧＬ３に流れる電流は、接地ラインＧＬ３に直列接続された抵抗２００、配線パターンＰ４、端子Ｅ２，及び接地ラインＧＬ４を介して、バッテリー１１の負極へと流れることになる。 The detection unit 71 includes a resistor 200 that detects the current flowing through the ground line GL3, and an amplifier circuit 201 that amplifies and outputs the voltage across the resistor 200. The resistor 200 is mounted between a terminal (not shown) of the connector C2 connected to the ground line GL3 and a wiring pattern P4 formed on the control board 22. FIG. That is, one end of the resistor 200 is connected to the ground line GL3, and the other end is connected to the wiring pattern P4. Therefore, the current flowing through the ground line GL3 flows to the negative electrode of the battery 11 via the resistor 200 connected in series with the ground line GL3, the wiring pattern P4, the terminal E2, and the ground line GL4.
　なお、図２は、制御基板２２における、抵抗２００、増幅回路２０１、マイコン７２ａ、及びコネクタＣ２の接続関係のみならず、制御基板２２上の実装された位置の概要を示している。本実施形態で、抵抗２００は、コネクタＣ２の直近に設けられ、コネクタＣ２から離れた位置に、増幅回路２０１と、マイコン７２ａとが設けられている。つまり、抵抗２００は、コネクタＣ２と、マイコン７２ａとの間に配置されている。このように、抵抗２００を、他の回路部品より、コネクタＣ２に近い位置に配置することにより、より精度良く、接地ラインＧＬ３の電流を計測することができる。 Note that FIG. 2 outlines not only the connection relationship of the resistor 200, the amplifier circuit 201, the microcomputer 72a, and the connector C2 on the control board 22, but also the mounted positions on the control board 22. FIG. In this embodiment, the resistor 200 is provided in the immediate vicinity of the connector C2, and the amplifier circuit 201 and the microcomputer 72a are provided at a position away from the connector C2. That is, the resistor 200 is arranged between the connector C2 and the microcomputer 72a. Thus, by arranging the resistor 200 at a position closer to the connector C2 than other circuit components, the current of the ground line GL3 can be measured with higher accuracy.
　マイコン７２ａは、図示しないＣＰＵ及びメモリ等を含む。マイコン７２ａのＣＰＵは、メモリに格納されたプログラムを実行することにより、マイコン７２ａに、各種機能ブロックを実現する。具体的には、マイコン７２ａには、判定部３００、及び制御部３０１が実現される。 The microcomputer 72a includes a CPU and memory (not shown). The CPU of the microcomputer 72a implements various functional blocks in the microcomputer 72a by executing programs stored in the memory. Specifically, a determination unit 300 and a control unit 301 are implemented in the microcomputer 72a.
　判定部３００は、増幅回路２０１の出力に基づいて、接地ラインＧＬ２がハイインピーダンス状態となったか否かを判定する。具体的には、判定部３００は、抵抗２００に流れる電流が所定値Ｔｈ（例えば、通常時の電流値（１００ｍＡ）より５０％高い値（１５０ｍＡ））以上となると、接地ラインＧＬ２がハイインピーダンス状態であると判定する。 Based on the output of the amplifier circuit 201, the determination unit 300 determines whether the ground line GL2 has entered a high impedance state. Specifically, when the current flowing through the resistor 200 reaches or exceeds a predetermined value Th (for example, a value (150 mA) that is 50% higher than the current value (100 mA) during normal operation), the determination unit 300 determines that the ground line GL2 is in a high impedance state. It is determined that
　ここで、「接地ラインＧＬ２がハイインピーダンス状態」とは、接地ラインＧＬ２に経年劣化、または断線が生じて接地ラインＧＬ２自身のインピーダンスが増加した状態と、接地ラインＧＬ２と、端子Ａ３，Ｂ２と、の間の接続状態が悪化し、端子Ａ３，Ｂ２間のインピーダンスが増加した状態と、を含む。なお、接地ラインＧＬ２がハイインピーダンス状態となった際の車両用灯具１０における電流経路等についての詳細は後述する。 Here, "the ground line GL2 is in a high-impedance state" refers to a state in which the impedance of the ground line GL2 itself is increased due to age-related deterioration or disconnection of the ground line GL2, the ground line GL2, the terminals A3 and B2, and a state in which the connection between the terminals A3 and B2 has deteriorated and the impedance between the terminals A3 and B2 has increased. Details of current paths and the like in the vehicle lamp 10 when the ground line GL2 is in a high impedance state will be described later.
　制御部３０１は、ＥＣＵ（不図示）から出力され、発光素子Ｄ１～Ｄｎの点灯条件を示す信号Ｓ１と、発光素子Ｄ１～Ｄｎの温度等の検出結果と、に基づいて、調整部５０を制御する信号を、通信ラインＣＬ１に出力する。なお、ここで、「発光素子Ｄの点灯条件」とは、例えば、発光素子Ｄを点灯させるか否か、点灯させる場合の輝度（発光素子Ｄに流す電流）を含む条件である。なお、制御部３０１は、例えば、発光素子Ｄ１～Ｄｎの温度が高い場合、点灯条件で定まる輝度が低くなるよう、調整部５０を制御する信号を生成する。つまり、制御部３０１は、発光素子Ｄ１～Ｄｎに対し、いわゆる温度ディレーティング制御を行う。 The control unit 301 controls the adjustment unit 50 based on a signal S1 that is output from an ECU (not shown) and indicates the lighting conditions of the light emitting elements D1 to Dn and detection results such as the temperatures of the light emitting elements D1 to Dn. A signal is output to the communication line CL1. Here, the “lighting condition of the light emitting element D” is a condition including, for example, whether or not the light emitting element D is to be lit, and luminance (current to be passed to the light emitting element D) when the light emitting element D is to be lit. Note that, for example, when the temperature of the light emitting elements D1 to Dn is high, the control unit 301 generates a signal for controlling the adjustment unit 50 so that the brightness determined by the lighting conditions is lowered. That is, the control unit 301 performs so-called temperature derating control on the light emitting elements D1 to Dn.
　また、制御部３０１は、抵抗２００に流れる電流が所定値Ｔｈ以上となり、判定部３００が、接地ラインＧＬ２がハイインピーダンス状態となったことを判定すると、図１に示すマイコン３１に対し、電源回路３０の動作を停止させるための信号を出力する。なお、本実施形態では、図１に示すマイコン３１と、マイコン７２との間には、通信ライン及び接地ラインを含むケーブル１０１が接続されている。 When the current flowing through the resistor 200 becomes equal to or greater than the predetermined value Th and the determination unit 300 determines that the ground line GL2 is in a high impedance state, the control unit 301 controls the microcomputer 31 shown in FIG. 30 outputs a signal to stop the operation. In this embodiment, a cable 101 including a communication line and a ground line is connected between the microcomputer 31 and the microcomputer 72 shown in FIG.
＝＝接地ラインＧＬ２が正常（ハイインピーダンス状態でない）の場合＝＝
　まず、図３を参照しつつ、接地ラインＧＬ２が正常な場合におけるＬＥＤデバイス４０に流れる電流の主な経路Ｙ１について説明する。なお、「接地ラインＧＬ２が正常な場合」とは、例えば、端子Ａ３と、端子Ｂ２との間を接続する接地ラインＧＬ２に劣化、断線等がなく、端子Ａ３と、端子Ｂ２との間のインピーダンスが小さい状態をいう。また、図３では、便宜上、電流の経路Ｙ１（点線）を説明する際の主要なブロックのみを図示している。さらに、図３と、図１とで同じ符号が付された部品、回路等は同じである。 ==When the ground line GL2 is normal (not in a high impedance state)==
First, referring to FIG. 3, the main path Y1 of current flowing through the LED device 40 when the ground line GL2 is normal will be described. Note that "when the ground line GL2 is normal" means, for example, that the ground line GL2 connecting between the terminals A3 and B2 is free from deterioration, disconnection, etc., and the impedance between the terminals A3 and B2 is is small. Also, in FIG. 3, for the sake of convenience, only main blocks are shown for explaining the current path Y1 (dotted line). Furthermore, the parts, circuits, etc. denoted by the same reference numerals in FIG. 3 and FIG. 1 are the same.
　図３において、電源回路３０は、電圧Ｖ２を端子Ａ４に印加するとともに、負荷である発光素子Ｄ１～Ｄｎに流れる電流Ｉ１～Ｉｎの合計値となる電流Ｉｓ１を、端子Ａ４から出力する。電流Ｉｓ１は、端子Ａ４，電源ラインＰＬ２、端子Ｂ１、発光素子Ｄ１～Ｄｎを介して、配線パターンＰ２へと流れることになる。 In FIG. 3, the power supply circuit 30 applies the voltage V2 to the terminal A4 and outputs from the terminal A4 a current Is1 that is the sum of the currents I1 to In flowing through the light emitting elements D1 to Dn as loads. Current Is1 flows to wiring pattern P2 via terminal A4, power supply line PL2, terminal B1, and light emitting elements D1 to Dn.
　ここで、配線パターンＰ２には、電源基板２０に接続される接地ラインＧＬ２と、ケーブル１００に含まれる接地ラインＧＬ３と、が接続されているが、接地ラインＧＬ２は、接地ラインＧＬ３のより十分太い。つまり、接地ラインＧＬ２のインピーダンスは、接地ラインＧＬ３のインピーダンスより十分小さくなるよう、それぞれのラインの太さが調整されている。したがって、本実施形態では、電源回路３０から出力され、配線パターンＰ２に流入する電流Ｉｓ１のほぼ全ては、端子Ｂ２、接地ラインＧＬ２、端子Ａ３を介して、電源基板２０へと流れることになる。 Here, the ground line GL2 connected to the power supply substrate 20 and the ground line GL3 included in the cable 100 are connected to the wiring pattern P2, and the ground line GL2 is sufficiently thicker than the ground line GL3. . That is, the thickness of each line is adjusted so that the impedance of the ground line GL2 is sufficiently smaller than the impedance of the ground line GL3. Therefore, in this embodiment, almost all of the current Is1 that is output from the power supply circuit 30 and flows into the wiring pattern P2 flows to the power supply board 20 via the terminal B2, the ground line GL2, and the terminal A3.
　このような場合、ＬＥＤ基板２１の配線パターンＰ２から、接地ラインＧＬ３を介して、制御基板２２へ流れる電流の値は非常に小さい。したがって、図２に示す、検出部７１の抵抗２００に流れる電流も小さいため、マイコン７２ａの判定部３００が、抵抗２００に流れる電流が所定値Ｔｈ以上である（接地ラインＧＬ２がハイインピーダンス状態である）と判定することはない。この結果、ＬＥＤデバイス４０の発光素子Ｄ１～Ｄｎは、信号Ｓ１、及び検出部５１の検出結果に応じた条件で点灯することになる。 In such a case, the value of the current flowing from the wiring pattern P2 of the LED board 21 to the control board 22 via the ground line GL3 is very small. Therefore, since the current flowing through the resistor 200 of the detection unit 71 shown in FIG. 2 is also small, the determination unit 300 of the microcomputer 72a determines that the current flowing through the resistor 200 is equal to or greater than the predetermined value Th (the ground line GL2 is in the high impedance state). ). As a result, the light-emitting elements D1 to Dn of the LED device 40 are lit under conditions corresponding to the signal S1 and the detection result of the detection section 51. FIG.
＝＝接地ラインＧＬ２が異常（ハイインピーダンス状態である）の場合＝＝
　つぎに、図４を参照しつつ、接地ラインＧＬ２が異常な場合におけるＬＥＤデバイス４０に流れる電流の主な経路Ｙ２について説明する。ここで、「接地ラインＧＬ２が異常な場合」とは、例えば、端子Ａ３と、端子Ｂ２との間を接続する接地ラインＧＬ２が、上述したハイインピーダンス状態となることをいう。なお、図４では、便宜上、電流の経路Ｙ２（一点鎖線）を説明する際の主要なブロックのみを図示している。さらに、図４と、図１とで同じ符号が付された部品、回路等は同じである。 == When the ground line GL2 is abnormal (high impedance state) ==
Next, the main path Y2 of the current flowing through the LED device 40 when the ground line GL2 is abnormal will be described with reference to FIG. Here, "when the ground line GL2 is abnormal" means, for example, that the ground line GL2 connecting between the terminal A3 and the terminal B2 is in the above-described high impedance state. For convenience, FIG. 4 shows only main blocks for explaining the current path Y2 (chain line). Further, parts, circuits, and the like denoted by the same reference numerals in FIG. 4 and FIG. 1 are the same.
　図４において、電源回路３０は、電圧Ｖ２を端子Ａ４に印加するとともに、負荷である発光素子Ｄ１～Ｄｎに流れる電流Ｉ１～Ｉｎの合計値となる電流Ｉｓ２を、端子Ａ４から出力する。電流Ｉｓ１は、端子Ａ４，電源ラインＰＬ２、端子Ｂ１、発光素子Ｄ１～Ｄｎを介して、配線パターンＰ２へと流れることになる。 In FIG. 4, the power supply circuit 30 applies the voltage V2 to the terminal A4 and outputs from the terminal A4 a current Is2 that is the sum of the currents I1 to In flowing through the light emitting elements D1 to Dn as loads. Current Is1 flows to wiring pattern P2 via terminal A4, power supply line PL2, terminal B1, and light emitting elements D1 to Dn.
　ここで、図４においては、例えば、端子Ａ３，Ｂ２の間を接続する接地ラインＧＬ２が断線していることとする。このような場合、配線パターンＰ２に流れる電流Ｉｓ２は、コネクタＣ１を介して、接地ラインＧＬ３へと流れる。そして、接地ラインＧＬ３へと流れた電流Ｉｓ２は、接地ラインＧＬ３が接続されたコネクタＣ２から、図２の検出部７１内の抵抗２００、配線パターンＰ４へと流れる。さらに、電流Ｉｓ２は、配線パターンＰ４から、端子Ｅ２、接地ラインＧＬ４、接地ラインＧｌ１を介して、バッテリー１１の負極へと流れることになる。 Here, in FIG. 4, for example, it is assumed that the ground line GL2 connecting between the terminals A3 and B2 is disconnected. In such a case, the current Is2 flowing through the wiring pattern P2 flows through the connector C1 to the ground line GL3. Then, the current Is2 flowing to the ground line GL3 flows from the connector C2 to which the ground line GL3 is connected to the resistor 200 and the wiring pattern P4 in the detection section 71 in FIG. Furthermore, the current Is2 flows from the wiring pattern P4 to the negative electrode of the battery 11 via the terminal E2, the ground line GL4, and the ground line Gl1.
　このような場合、図２に示す抵抗２００に流れる電流は所定値Ｔｈより大きくなるため、マイコン７２ａの判定部３００は、抵抗２００に流れる電流が所定値Ｔｈ以上である（接地ラインＧＬ２がハイインピーダンス状態である）と判定する。 In such a case, the current flowing through the resistor 200 shown in FIG. state).
　そして、マイコン７２ａの制御部３０１は、判定部３００の判定結果に基づいて、電源回路３０の動作を停止させる信号を、ケーブル１０１を介してマイコン３１に出力する。この結果、マイコン３１は、電源回路３０の動作を停止させることになる。電源回路３０の動作が停止すると、電圧Ｖ２の生成も停止される。したがって、ＬＥＤデバイス４０から、接地ラインＧＬ３に流れる電流も十分小さくなる（ほぼゼロとなる）。 Then, the control unit 301 of the microcomputer 72 a outputs a signal for stopping the operation of the power supply circuit 30 to the microcomputer 31 via the cable 101 based on the determination result of the determination unit 300 . As a result, the microcomputer 31 stops the operation of the power supply circuit 30 . When the operation of the power supply circuit 30 is stopped, the generation of the voltage V2 is also stopped. Therefore, the current flowing from the LED device 40 to the ground line GL3 is also sufficiently small (substantially zero).
　このように、車両用灯具１０では、電源基板２０と、ＬＥＤ基板２１と、の間を接続する接地ラインＧＬ２がハイインピーダンス状態になった場合であっても、ケーブル１００の接地ラインＧＬ３に大きな電流が流れることを防ぐことができる。したがって、本実施形態では、情報のやりとりに用いられるケーブル１００を、大電流から適切に保護することができる。 Thus, in the vehicle lamp 10, even when the ground line GL2 connecting between the power supply board 20 and the LED board 21 is in a high impedance state, a large current flows through the ground line GL3 of the cable 100. can be prevented from flowing. Therefore, in this embodiment, the cable 100 used for exchanging information can be appropriately protected from a large current.
＝＝＝他の実施形態＝＝＝
　図５は、図２に示すマイコン７２ａの判定部３００をコンパレータ７５で実現させた場合の実施形態を示す図である。なお、図５においては、電源回路７０等は適宜省略し、図１及び図２と、同じ符号が付されたブロック（回路、端子等）は、同じである。 ===Other Embodiments===
FIG. 5 is a diagram showing an embodiment in which the determination section 300 of the microcomputer 72a shown in FIG. 5, the power supply circuit 70 and the like are omitted as appropriate, and blocks (circuits, terminals, etc.) denoted by the same reference numerals as in FIGS. 1 and 2 are the same.
　コンパレータ７５は、増幅回路２０１の出力と、基準電圧Ｖｒｅｆとを比較し、接地ラインＧＬ２がハイインピーダンス状態となったか否かを判定する。ここで、基準電圧Ｖｒｅｆのレベルは、抵抗２００に流れる電流が所定値Ｔｈとなる際の増幅回路２０１の出力のレベルに設定されている。したがって、増幅回路２０１の出力が、基準電圧Ｖｒｅｆより高くなると、コンパレータ７５は、抵抗２００に流れる電流が所定値Ｔｈより高いこと判定する。つまり、コンパレータ７５は、増幅回路２０１の出力が、基準電圧Ｖｒｅｆより高くなると、接地ラインＧＬ２がハイインピーダンス状態であることを判定する「判定部」として動作する。 A comparator 75 compares the output of the amplifier circuit 201 with the reference voltage Vref to determine whether the ground line GL2 has entered a high impedance state. Here, the level of the reference voltage Vref is set to the level of the output of the amplifier circuit 201 when the current flowing through the resistor 200 reaches a predetermined value Th. Therefore, when the output of the amplifier circuit 201 becomes higher than the reference voltage Vref, the comparator 75 determines that the current flowing through the resistor 200 is higher than the predetermined value Th. That is, the comparator 75 operates as a "determining unit" that determines that the ground line GL2 is in the high impedance state when the output of the amplifier circuit 201 becomes higher than the reference voltage Vref.
　マイコン７２ｂには、上述した制御部３０１が実現される。制御部３０１は、コンパレータ７５から、接地ラインＧＬ２がハイインピーダンス状態であることを示す判定結果が出力されると、電源回路３０の動作を停止すべく、マイコン３１に所定の信号を送信する。この結果、図５に示すコンパレータ７５、及びマイコン７２ｂを用いた場合であっても、接地ラインＧＬ３に大きな電流が流れることを防ぐことができる。 The control unit 301 described above is implemented in the microcomputer 72b. When the comparator 75 outputs the determination result indicating that the ground line GL2 is in the high impedance state, the control unit 301 transmits a predetermined signal to the microcomputer 31 to stop the operation of the power supply circuit 30 . As a result, even when the comparator 75 and the microcomputer 72b shown in FIG. 5 are used, it is possible to prevent a large current from flowing through the ground line GL3.
＝＝＝変形例＝＝＝
＜＜灯具＞＞
　図１に示した灯具は、車両用灯具１０であることとしたがこれに限られない。例えば、図１に示した灯具は、街路灯や一般的な照明器具に用いられても良い。そのような場合であっても、マイコン７２ａは、電源基板２０と、ＬＥＤ基板２１との間の接地ラインＧＬ２がハイインピーダンス状態であるか否かを判定することができる。 === Variation ===
<< Light fixture >>
Although the lamp shown in FIG. 1 is the vehicle lamp 10, it is not limited to this. For example, the lamp shown in FIG. 1 may be used as a street lamp or a general lighting fixture. Even in such a case, the microcomputer 72a can determine whether the ground line GL2 between the power supply substrate 20 and the LED substrate 21 is in the high impedance state.
＜＜電圧源＞＞
　また、図１の灯具は、バッテリー１１を電圧源として動作することとしたが、バッテリー１１以外の電圧源が接続されても良い。具体的には、商用電源を所定電圧に変換するＡＣ－ＤＣコンバータ（不図示）や、ＤＣ－ＤＣコンバータを電圧源として動作することとしても良い。 <<Voltage source>>
Also, although the lamp in FIG. 1 operates using the battery 11 as a voltage source, a voltage source other than the battery 11 may be connected. Specifically, an AC-DC converter (not shown) that converts a commercial power supply to a predetermined voltage or a DC-DC converter may be operated as a voltage source.
＜＜検出部＞＞
　また、マイコン７２は、接地ラインＧＬ３に流れる電流を、抵抗２００の両端の電圧として検出する検出部を有しても良い。このような場合であっても、本実施形態と同様に、接地ラインＧＬ２の状態を把握することができる。 <<Detector>>
Further, the microcomputer 72 may have a detection section that detects the current flowing through the ground line GL3 as the voltage across the resistor 200. FIG. Even in such a case, the state of the ground line GL2 can be grasped as in the present embodiment.
＜＜抵抗２００の位置＞＞
　また、検出部７１における抵抗２００は、接地ラインＧＬ３に流れる電流を検出できるよう、コネクタＣ２の端子（不図示）と、配線パターンＰ４との間に接続されたがこれに限られない。例えば、抵抗２００は、接地ラインＧＬ４に流れる電流を検出できるよう、配線パターンＰ４と、端子Ｅ２との間に接続されても良い。このような位置に抵抗２００が配置された場合であっても、接地ラインＧＬ２がハイインピーダンス状態であるか否かを検出することができる。 <<position of resistor 200>>
Also, the resistor 200 in the detection unit 71 is connected between the terminal (not shown) of the connector C2 and the wiring pattern P4 so as to detect the current flowing through the ground line GL3, but the present invention is not limited to this. For example, the resistor 200 may be connected between the wiring pattern P4 and the terminal E2 so as to detect the current flowing through the ground line GL4. Even when resistor 200 is arranged at such a position, it is possible to detect whether or not ground line GL2 is in the high impedance state.
　ただし、接地ラインＧＬ４には、電源回路７０、マイコン７２からの電流も定常的に流れる。このため、抵抗２００を配線パターンＰ４と、端子Ｅ２との間に接続するより、コネクタＣ２と、配線パターンＰ４との間に接続した場合の方が、抵抗２００で消費される電力を小さくすることができる。 However, current from the power supply circuit 70 and the microcomputer 72 also steadily flows through the ground line GL4. Therefore, the power consumed by the resistor 200 can be reduced when the resistor 200 is connected between the connector C2 and the wiring pattern P4 rather than when the resistor 200 is connected between the wiring pattern P4 and the terminal E2. can be done.
　また、通常時（正常時）において、ケーブル１００の接地ラインＧＬ３に流れる電流値は、比較的小さい。このため、抵抗２００をコネクタＣ２と、配線パターンＰ４との間に接続することにより、精度良く、接地ラインＧＬ２の異常を検出することができる。
＝＝＝まとめ＝＝＝
　以上、本実施形態の車両用灯具１０について説明した。車両用灯具１０では、検出部７１は、接地ラインＧＬ３に流れる電流を検出し、判定部３００は、検出部７１の検出結果に基づいて、接地ラインＧＬ２がハイインピーダンス状態であるか否かを判定できる。このため、車両用灯具１０では、電圧レギュレータである電源回路３０を用いる場合であっても、接地ラインＧＬ２の断線等を検出することができる。 In addition, the current value flowing through the ground line GL3 of the cable 100 is relatively small at normal times (normal times). Therefore, by connecting the resistor 200 between the connector C2 and the wiring pattern P4, it is possible to accurately detect the abnormality of the ground line GL2.
===Summary===
The vehicle lamp 10 of the present embodiment has been described above. In the vehicle lamp 10, the detection unit 71 detects the current flowing through the ground line GL3, and the determination unit 300 determines whether or not the ground line GL2 is in a high impedance state based on the detection result of the detection unit 71. can. Therefore, in the vehicle lamp 10, disconnection or the like of the ground line GL2 can be detected even when the power supply circuit 30, which is a voltage regulator, is used.
　また、本実施形態では、調整部５０と、制御部３０１と、を接続する通信ラインＣＬ１で接続されているため、ＬＥＤデバイス４０の発光条件を調整することができる。 In addition, in the present embodiment, since the communication line CL1 connecting the adjustment unit 50 and the control unit 301 is used, the light emission conditions of the LED device 40 can be adjusted.
　また、抵抗２００は、接地ラインＧＬ３に直列接続され、検出部７１は、接地ラインＧＬ３に流れる電流を検出する。このため、例えば、接地ラインＧＬ４に流れる電流を検出する構成とする場合に比べ、精度良く、接地ラインＧＬ２の異常を検出できる。 Also, the resistor 200 is connected in series to the ground line GL3, and the detection section 71 detects the current flowing through the ground line GL3. Therefore, an abnormality in the ground line GL2 can be detected with high accuracy, for example, compared to a configuration that detects the current flowing through the ground line GL4.
　また、抵抗２００は、例えば、図２で示すように、制御基板２２において、コネクタＣ２の直近に実装されている。したがって、抵抗２００で消費される電力を低減することができる。 Also, the resistor 200 is mounted in the immediate vicinity of the connector C2 on the control board 22, for example, as shown in FIG. Therefore, the power consumed by resistor 200 can be reduced.
　また、本実施形態では、接地ラインＧＬ２は、接地ラインＧＬ３より太いため、接地ラインＧＬ２が正常の場合、接地ラインＧＬ３に流れる電流値を小さくすることができる。 Also, in the present embodiment, since the ground line GL2 is thicker than the ground line GL3, the current value flowing through the ground line GL3 can be reduced when the ground line GL2 is normal.
　また、制御部３０１は、接地ラインＧＬ２がハイインピーダンス状態である場合、電源回路３０の動作を停止させる。このため、接地ラインＧＬ３に大電流が流れることを防ぐことができる。 Also, the control unit 301 stops the operation of the power supply circuit 30 when the ground line GL2 is in a high impedance state. Therefore, it is possible to prevent a large current from flowing through the ground line GL3.
　また、例えば、本実施形態では、ＬＥＤデバイス４０（光源）は、ヘッドライトに適用されることとしたが、例えば、街路灯に適用されても良い。そのような場合であっても、本実施形態と同様の効果を得ることができる。 Also, for example, in the present embodiment, the LED device 40 (light source) is applied to headlights, but may be applied to street lights, for example. Even in such a case, effects similar to those of the present embodiment can be obtained.
　上記の実施形態は、本開示の理解を容易にするためのものであり、本開示を限定して解釈するためのものではない。また、本開示は、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、本開示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 for facilitating understanding of the present disclosure, and are not for limiting interpretation of the present disclosure. Further, it goes without saying that the present disclosure may be modified or improved without departing from its spirit, and that equivalents thereof are included in the present disclosure.
　本出願は、２０２１年７月１６日出願の日本特許出願（特願２０２１－１１７８８３）に基づくものであり、その内容はここに参照として取り込まれる。 This application is based on a Japanese patent application (Japanese Patent Application No. 2021-117883) filed on July 16, 2021, the contents of which are incorporated herein by reference.
　本開示によれば、電圧レギュレータを用いつつ、接地ラインのインピーダンスの増加を検出することができる灯具を提供できる。 According to the present disclosure, it is possible to provide a lamp that can detect an increase in the impedance of the ground line while using a voltage regulator.
１０　車両用灯具
１１　バッテリー
２０　電源基板
２１　ＬＥＤ基板
２２　制御基板
３０，７０　電源回路
３１，７２　マイコン
４０　ＬＥＤデバイス
５０　調整部
５１，７１　検出部
７５　コンパレータ
１００，１０１　ケーブル
２００　抵抗
２０１　増幅回路
ＣＳ１～ＣＳｎ　電流源
Ｄ１～Ｄｎ　発光素子
Ａ１～Ａ４，Ｂ１，Ｂ２，Ｅ１，Ｅ２　端子
Ｃ１，Ｃ２　コネクタ
ＰＬ１～ＰＬ３　電源ライン
ＧＬ１～ＧＬ４　接地ライン
ＣＬ１，ＣＬ２　通信ライン
Ｐ１～Ｐ４　配線パターン
  10 Vehicle lamp 11 Battery 20 Power supply board 21 LED board 22 Control boards 30, 70 Power supply circuits 31, 72 Microcomputer 40 LED device 50 Adjustment units 51, 71 Detection unit 75 Comparators 100, 101 Cable 200 Resistor 201 Amplifier circuits CS1 to CSn Current Sources D1 to Dn Light emitting elements A1 to A4, B1, B2, E1, E2 Terminals C1, C2 Connectors PL1 to PL3 Power supply lines GL1 to GL4 Ground lines CL1, CL2 Communication lines P1 to P4 Wiring patterns

Claims (7)

  1. 　電圧源の第１電圧が印加される第１電源ラインと、第１接地ラインとが接続され、第２電圧を第２電源ラインに印加する電圧レギュレータと、
    　前記第２電源ラインと、前記第１接地ラインに接続された第２接地ラインとが接続された光源と、
    　前記第２接地ラインに接続された第３接地ラインと、前記第１接地ラインに接続された第４接地ラインと、前記光源からの通信ラインとが接続され、前記光源を制御する制御部と、
    　前記第３接地ライン、または前記第４接地ラインに流れる電流を検出する検出部と、
    　前記検出部の検出結果に基づいて、前記第２接地ラインがハイインピーダンス状態になったか否かを判定する判定部と、
    　を備える灯具。     a voltage regulator connected to a first power supply line to which a first voltage of a voltage source is applied and a first ground line and applying a second voltage to the second power supply line;
    a light source to which the second power supply line and a second ground line connected to the first ground line are connected;
    a control unit connected to a third ground line connected to the second ground line, a fourth ground line connected to the first ground line, and a communication line from the light source and controlling the light source;
    a detection unit that detects a current flowing through the third ground line or the fourth ground line;
    a determination unit that determines whether or not the second ground line is in a high impedance state based on the detection result of the detection unit;
    A lamp with
  2. 　前記光源は、複数の発光素子と、前記複数の発光素子のそれぞれに流れる電流を調整する調整部と、を含み、
    　前記通信ラインは、前記調整部と、前記制御部とを接続する、
    　請求項１に記載の灯具。     The light source includes a plurality of light emitting elements and an adjustment unit that adjusts the current flowing through each of the plurality of light emitting elements,
    the communication line connects the adjustment unit and the control unit;
    The lamp according to claim 1.
  3. 　前記第３接地ラインに直列接続された抵抗を含み、
    　前記検出部は、前記抵抗に生じる電圧に基づいて、前記第３接地ラインに流れる電流を検出する、
    　請求項１または請求項２に記載の灯具。     including a resistor connected in series with the third ground line;
    The detection unit detects the current flowing through the third ground line based on the voltage generated across the resistor.
    The lamp according to claim 1 or 2.
  4. 　前記第３接地ラインが接続されたコネクタと、
    　前記コネクタと、前記制御部と、前記検出部と、前記抵抗とが実装された基板と、
    　を含み、
    　前記抵抗は、前記基板において、前記コネクタと、前記制御部との間に配置される、
    　請求項３に記載の灯具。     a connector to which the third ground line is connected;
    a substrate on which the connector, the control unit, the detection unit, and the resistor are mounted;
    including
    the resistor is arranged on the substrate between the connector and the control unit;
    The lamp according to claim 3.
  5. 　前記第２接地ラインは、第３接地ラインより太い、
    　請求項３または請求項４に記載の灯具。     the second ground line is thicker than the third ground line,
    The lamp according to claim 3 or 4.
  6. 　前記制御部は、前記第２接地ラインがハイインピーダンス状態であることが判定されると、前記電圧レギュレータの動作を停止させる、
    　請求項１～５の何れか一項に記載の灯具。     The control unit stops the operation of the voltage regulator when it is determined that the second ground line is in a high impedance state.
    The lighting fixture according to any one of claims 1 to 5.
  7. 　前記灯具は、車両に用いられる、
    　請求項１～６の何れか一項に記載の灯具。     The lamp is used in a vehicle,
    The lighting fixture according to any one of claims 1 to 6.
PCT/JP2022/024934 2021-07-16 2022-06-22 Lamp WO2023286550A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017056854A (en) * 2015-09-17 2017-03-23 市光工業株式会社 Display lamp device
JP2018113175A (en) * 2017-01-12 2018-07-19 東芝ライテック株式会社 Power supply device and illumination device equipped with this power supply device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017056854A (en) * 2015-09-17 2017-03-23 市光工業株式会社 Display lamp device
JP2018113175A (en) * 2017-01-12 2018-07-19 東芝ライテック株式会社 Power supply device and illumination device equipped with this power supply device

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