JP2015080999A - Lighting fixture for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve an adequate operation when a light-emitting element part is disconnected.SOLUTION: In a case that a lighting fixture is equipped with first to n-th light-emitting element parts, which are respectively so configured as to have one or more semiconductor light-emitting elements and are connected to one another in a parallel relationship, and a power consumption part connected to the plural light-emitting element parts in parallel, a switch part for power consumption which switches between on and off of current supply to the power consumption part is provided. In a case that disconnection is detected by any one of first to n-th disconnection detection parts which respectively correspond to the first to n-th light-emitting element parts, a switch control part, which so controls the switch part for power consumption as to be switched off, is provided. Thus, current supply to the power consumption part is stopped during disconnection, while current supply to the light-emitting element part which can emit light is continued, whereby light-emitting action is maintained.

Description

  The present invention relates to a vehicular lamp.

Japanese Patent Application Laid-Open No. 2004-9825

  Patent Document 1 discloses a technology for stopping power supply to a lamp in which a disconnection of a light emitting element has occurred or blinking light emitting elements of other lamps in a short cycle as a vehicular lamp using a semiconductor light emitting element. Has been.

  Incidentally, as in Patent Document 1, there is a lamp provided with power consuming means such as a dummy load circuit in parallel with a light emitting element group as a lamp used as a turn signal lamp. For example, in the case of a configuration using a semiconductor light emitting element such as an LED (Light Emitting Diode), the power consumption is made equal to the case where a conventional incandescent bulb is used, thereby maintaining the compatibility of the vehicle lamp with the vehicle side. Because. This makes it unnecessary to change the design of the control system / feeding system on the vehicle side when the vehicular lamp of the semiconductor light emitting element is mounted on the vehicle body.

In the technique of Patent Document 1, when a disconnection of a light emitting element in a lamp is detected, the lamp turns off the power input path and stops supplying power to the entire light emitting element and the dummy load circuit. Yes. For this reason, even if there is a light emitting element portion where no disconnection occurs, the light emission of that portion is also stopped.
In the control unit on the vehicle body side that supplies power to the lamp, it is possible to detect a disconnection state by a current decrease caused by power input being stopped on the lamp side. In this case, it is also described that the disconnection is notified to the driver (driver) by advancing the blinking cycle of other lamps. In that sense, stopping the power input in the lamp in which the disconnection has occurred is also because the disconnection state can be detected on the vehicle body side.
However, stopping the power supply to the entire light emitting element in which the disconnection has occurred causes the light emitting elements in the lamp in which the disconnection has occurred to be turned off.

  In view of this, the present invention is a method for driving a portion capable of emitting light to emit light and maintaining the light emission operation as much as possible even when a disconnection occurs in part, while also allowing the external (vehicle side) control system to recognize the disconnection. Propose.

First, the vehicular lamp according to the present invention is configured such that each of n has one or a plurality of semiconductor light emitting elements, and n are connected in parallel to each other when n is an integer of 2 or more. An nth light emitting element unit; a power consuming unit connected in parallel to the plurality of light emitting element units; a power consuming switch unit for turning on / off current supply to the power consuming unit; Either one of the first to n-th disconnection detecting units provided corresponding to each of the n light-emitting element units and detecting the disconnection of the corresponding light-emitting element unit, and the first to n-th disconnection detecting units. And a switch control unit that controls the power consumption switch unit to be turned off when a disconnection is detected.
Even if there is a disconnection in any of the first to nth light emitting element parts, the light emitting element part that is not disconnected functions normally by not stopping the power supply to the light emitting element part. Then, the amount of current is reduced by turning off the current supply to the power consumption unit connected in parallel with the light emitting element unit.

Second, in the vehicle lamp according to the present invention described above, the power consumption switch unit is connected in series with the power consumption unit, and the power connection switch unit and the power consumption unit are connected in series. It is desirable that the first to nth light emitting element portions are connected in parallel.
As a result, the current consuming switch unit turns on / off the current only to the power consuming unit.

3rdly, in the vehicle lamp which concerns on above-described this invention, it is desirable that each of the said 1st-nth light emitting element part is comprised by the serial connection of several semiconductor light emitting elements.
That is, a plurality of light emitting element portions are provided as a series connection of a plurality of semiconductor light emitting elements. The light emitting element portion where the disconnection has occurred cannot be turned on, but in the other light emitting element portions, a light emitting operation is performed by connecting a plurality of semiconductor light emitting elements in series.

4thly, in the vehicle lamp which concerns on above-mentioned this invention, the said 1st-nth light emitting element part comprises the turn signal lamp for vehicles, and receives the pulse voltage supplied from the vehicle side control part. The vehicle lamp that performs flashing light emission in the first to nth light emitting element portions. Here, when the output current to the vehicle lamp is greater than or equal to a predetermined current value, the vehicle-side control unit supplies a pulse voltage of the first frequency to the vehicle lamp, and the output current to the vehicle lamp is less than the predetermined current value. In this case, a pulse voltage having a second frequency higher than the first frequency is supplied to the vehicle lamp. Here, regarding the input current supplied from the vehicle-side control unit, the sum of the input currents consumed by the n light emitting systems related to the first to nth light emitting element units is consumed by the Idal and the power consuming unit. The input current consumed is Ir, and the input current consumed by the remaining (n−1) light emitting systems when a disconnection occurs in one of the n light emitting systems of the first to nth light emitting element units. Where Ids <the predetermined current value <(Idal + Ir).
Since the power consumption unit is used, power is consumed in addition to the light emitting operation. Therefore, in order to reduce unnecessary power consumption, the configuration of the vehicular lamp of the present invention is suitable for a turn signal lamp with a short lighting time. . In this case, the current consumption is set so as to satisfy the above formula with respect to the predetermined current value, so that a high-speed blinking is performed at the time of partial disconnection.

  According to the present invention, even when disconnection occurs in part, it is possible to realize the operation of exhibiting the function as a lamp as much as possible by driving the light emitting portion to emit light and maintaining the light emitting operation as much as possible. In addition, by turning off the current supply to the power consuming unit at the time of disconnection, the disconnection can be recognized by the external (vehicle side) control system.

It is a block diagram of the vehicular lamp of an embodiment of the invention. It is a circuit diagram of the light emitting element part of embodiment, and a disconnection detection part. It is a circuit diagram of the switch part for power consumption of embodiment, and a power consumption part. It is a circuit diagram of the low voltage monitoring part and switch control part of an embodiment.

Hereinafter, a vehicular lamp according to an embodiment will be described with reference to FIGS. Let the vehicle lamp 1 of embodiment be an example used as a turn signal lamp.
As shown in FIG. 1, the vehicular lamp 1 is connected to a vehicle-side control unit 2 and terminals 10 and 11. The terminal 11 is, for example, a ground terminal.
The vehicle-side control unit 2 supplies a pulse voltage Vp of 24V to the terminal 10 with a period of 0.7 seconds as an example in accordance with the driver's turn signal lamp lighting operation. The pulse voltage Vp input to this terminal 10 is used directly as the light emission drive voltage.

The vehicle-side control unit 2 changes the cycle of the pulse voltage Vp to be output according to the output current. For example, if the output current value is greater than or equal to a predetermined value, for example, a pulse having a period of 0.7 seconds is used, and if the output current value is less than the predetermined value, for example, a pulse having a period of 0.35 seconds is used.
Since the vehicular lamp 1 has a configuration in which the semiconductor light emitting element is driven to emit light with a driving current based on the pulse voltage Vp, for example, when a pulse having a period of 0.7 seconds is supplied, a normal period of 0.7 seconds is used. The turn signal lamp blinks. When a pulse having a cycle of 0.35 seconds is supplied, a so-called high flasher state in which high-speed blinking with a cycle of 0.35 seconds is performed.

  As shown in FIG. 1, the vehicular lamp 1 according to the present embodiment includes a protection circuit 12, a voltage control circuit 13, an overvoltage monitoring unit 14, a reference voltage generation unit 15, a low voltage monitoring unit 16, and light emitting element units 17A and 17B. , 17C, constant current circuits 18A, 18B, 18C, disconnection detection units 19A, 19B, 19C, a power consumption switch 20, a power consumption unit 21, and a switch control unit 22.

A protection circuit 12 and a voltage control circuit 13 are provided on the drive power supply line 31 from the terminal 10.
The protection circuit 12 includes a reverse connection protection circuit and a surge protection circuit.
The voltage control circuit 13 includes at least one of an overvoltage protection switch that cuts off when an overvoltage is applied, and a DC / DC converter that steps up or steps down the input voltage (= Vp).
Here, it is assumed that at least an overvoltage protection switch is provided. The overvoltage protection switch is normally turned on and applies the pulse voltage Vp to the light emitting element portions 17A, 17B, and 17C, and is turned off when the overvoltage state is reached.
For this operation, the overvoltage monitoring unit 14 monitors whether or not the voltage supplied from the terminal 10 to the drive power supply line 31 is in an overvoltage state (for example, 36 V or more), and the voltage is detected when the overvoltage state is detected. A circuit configuration is employed in which the overvoltage protection switch in the control circuit 13 is turned off.
When the overvoltage protection switch is turned off, the subsequent light emitting element portions 17A, 17B, and 17C are disconnected from the drive power supply line 31, and the drive current is not supplied. That is, an excessive voltage is prevented from being applied to the light emitting element portions 17A, 17B, and 17C, and the light emitting element portions 17A, 17B, and 17C are protected.

Each of the light emitting element portions 17A, 17B, and 17C is constituted by a series connection of six LEDs as semiconductor light emitting elements as shown in FIG. The light emitting element portions 17A, 17B, and 17C are connected to each other in parallel as viewed from the drive power supply line 31.
Constant current circuits 18A, 18B, and 18C are provided for the light emitting element portions 17A, 17B, and 17C, respectively. The LED groups as the light emitting element portions 17A, 17B, and 17C are driven to emit light at a constant current by the constant current circuits 18A, 18B, and 18C.

  The reference voltage generation unit 15 generates a necessary reference voltage Vref using the input voltage. This reference voltage Vref is used as a comparison reference for constant current control of the current flowing through the light emitting element portions 17A, 17B, and 17C in the constant current circuits 18A, 18B, and 18C.

The low voltage monitoring unit 14 monitors whether the pulse voltage Vp supplied to the terminal 10 is in a low voltage state (for example, 16 V or less). When the low voltage is detected, the low voltage monitoring unit 16 supplies the low voltage detection signal Su to the switch control unit 22 through the detection line 32.
Also, disconnection detectors 19A, 19B, and 19C are provided for the light emitting element portions 17A, 17B, and 17C, respectively. The disconnection detection units 19A, 19B, and 19C detect disconnection states in the corresponding light emitting element units 17A, 17B, and 17C, respectively. When any one of the disconnection detection units 19A, 19B, and 19C detects a disconnection, the disconnection detection signal Sd is supplied to the switch control unit 22 by the detection line 30.

On the drive power supply line 31, the power consumption switch unit 20 and the power consumption unit 21 are connected in parallel with the light emitting element units 17A, 17B, and 17C.
As shown in FIG. 3, the power consuming unit 21 is configured as a dummy load circuit including a large number of dummy resistors r.
The power consumption switch unit 20 includes a switch circuit that can disconnect the power consumption unit 21 from the drive power supply line 31 and turn off the current supply to the power consumption unit 21.
The power consuming switch unit 20 turns on / off current supply under the control of the switch control unit 22.
The switch control unit 22 performs an operation of turning off the power consumption switch unit 20 in accordance with the disconnection detection signal Sd and the low voltage detection signal Su described above.

Here, in the configuration of FIG. 1 described above, the input current consumed by the light emitting element portions 17A, 17B, and 17C and the constant current circuits 18A, 18B, and 18C is Iin1, Iin2, Iin3, and the power consuming portion. The input current consumed at 21 is Ir.
The sum of input currents (= Iin1 + Iin2 + Iin3) consumed by the three light emitting systems related to the light emitting element portions 17A, 17B, and 17C is defined as Idal.
Further, Ids is the maximum value as the sum of the input currents consumed by the remaining two light emitting systems when a disconnection occurs in one of the three light emitting systems related to the light emitting element portions 17A, 17B, and 17C.
The vehicle side control unit 2
Supplying a pulse voltage Vp having a predetermined frequency (first frequency) so as to perform a normal blinking operation when the output current to the vehicular lamp 1 is equal to or greater than a predetermined current value Ic;
When the output current to the vehicular lamp 1 is less than the predetermined current value Ic, the pulse voltage Vp having a higher frequency (second frequency) is supplied so as to perform a blinking operation faster than the normal blinking.
In this case, in the vehicular lamp 1 of the present embodiment,
Ids <Ic <(Idal + Ir)
Iin1, Iin2, Iin3, and Ir are set so as to satisfy the above.
However, “Ids” indicates the maximum value as the sum of the input currents consumed in the remaining two systems when a disconnection occurs in one of the three light emitting systems related to the light emitting element units 17A, 17B, and 17C. .
For example, when the light emitting element portion 17A is disconnected, the current consumption by the remaining two systems = Iin1 + Iin3, when the light emitting element portion 17B is disconnected, the current consumption by the remaining two systems = Iin2 + Iin3, and when the light emitting element portion 17B is disconnected, the remaining power Current consumption by the two systems = Iin1 + Iin2, but “Ids” is the maximum value among “Iin1 + Iin3”, “Iin2 + Iin3”, and “Iin1 + Iin2”.

The circuit configuration of the disconnection detectors 19A, 19B, and 19C will be described with reference to FIG.
The disconnection detectors 19A, 19B, and 19C have the same circuit configuration. Each includes a differential amplifier AP1, resistors R1 to R5, capacitors C1 to C3, and an NPN transistor Q1. The disconnection detectors 19A, 19B and 19C are supplied with a comparison voltage Vcp generated by dividing the voltage Vcc line with resistors R10 and R11.

The disconnection detection unit 19A will be described as a representative. The cathode side in the series connection of the LEDs of the light emitting element portion 17A is connected to the inverting input terminal of the differential amplifier AP1 via the resistor R1. A capacitor C1 is connected between the inverting input terminal and the ground. The comparison voltage Vcp is input to the non-inverting input terminal of the differential amplifier AP1 through the resistor R5. The resistor R2 is a feedback resistor of the differential amplifier AP1.
The output terminal of the differential amplifier AP1 is connected to the base of the NPN transistor Q1 via the resistor R3. A capacitor C3 is connected between the output terminal of the differential amplifier AP1 and the ground. A resistor R4 is connected between the base and emitter of the NPN transistor Q1, and the emitter is connected to the ground. The collector of the NPN transistor Q1 is connected to the output line 30. A capacitor C2 for removing noise from the detection signal is inserted between the detection line 30 and the ground.

In such a disconnection detector 19A, disconnection detection is performed as follows.
When the light emission operation as the turn signal lamp is performed, the pulse voltage Vp is applied to the light emitting element portion 17A, and the light emission drive current flows intermittently according to the voltage application. When there is no disconnection and the light emission drive current normally flows at intermittent cycles, a voltage smoothed by charging / discharging of the capacitor C1 is applied to the inverting input terminal of the differential amplifier AP1. On the other hand, when a disconnection occurs in the LED series circuit in the light emitting element portion 17A and no current flows, the potential at the inverting input terminal of the differential amplifier AP1 is lowered.
That is, when the potential at the inverting input terminal of the differential amplifier AP1 falls below the comparison voltage Vcp due to disconnection, the output voltage of the differential amplifier AP1 rises, a base current is applied to the NPN transistor Q1, and the NPN transistor Q1 is turned on. . As a result, the detection line 30 is almost at the ground level.
As will be described later with reference to FIG. 4, the detection line 30 is normally set to a predetermined potential. The potential of the detection line 30 is the disconnection detection signal Sd, and this potential is almost at the ground level, indicating disconnection detection.

  Here, as can be seen from FIG. 2, the detection line 30 is common to the disconnection detection units 19A, 19B, and 19C. That is, the NPN transistors Q1 of the disconnection detectors 19A, 19B, and 19C are connected. Therefore, when any one of the light emitting element portions 17A, 17B, and 17C is disconnected, the potential of the detection line 30, that is, the disconnection detection signal Sd becomes the ground level.

Next, the circuit configuration of the power consumption switch unit 20 will be described with reference to FIG. The power consuming switch unit 20 includes a switch transistor Q10, a control transistor Q11, resistors R11 to R13, and capacitors C10 and C11.
The switching transistor Q10 is configured by, for example, a P-channel FET (Field Effect Transistor), and the source and drain thereof are connected between the drive power supply line 31 and the power consumption unit 21. That is, when the switching transistor Q10 is turned on, a current flows through the power consumption unit 21, and when it is turned off, the current supply to the power consumption unit 21 is turned off.
A capacitor C10 and a resistor R12 are connected between the gate and source of the switching transistor Q10, and a collector of the control transistor Q11, which is an NPN transistor, is connected to the gate of the switching transistor Q10 via a resistor R11.
A resistor R15 is connected between the base and emitter of the control transistor Q11, and the base is connected to the drive power supply line 31 via resistors R14 and R13. A capacitor C11 is inserted between the base and ground. The emitter of the control transistor Q11 is connected to the ground. Here, a connection point between the resistor R14 and the capacitor C11 is shown as a connection point TA, and this connection point TA is connected to a switch control unit 22 described below with reference to FIG.

The circuit configuration of the switch control unit 22 and the low voltage monitoring unit 16 will be described with reference to FIG.
As shown in FIG. 4, the low voltage monitoring unit 16 includes a Zener diode ZD, a capacitor C20, resistors R20 and R21, and an NPN transistor Q20 whose cathode side is connected to the drive power supply line 31. The anode of the Zener diode ZD is connected to the base of the NPN transistor Q20 via the resistor R20, and a capacitor C20 is connected between the anode and ground. The resistor R21 is connected between the base and emitter of the NPN transistor Q20, and the emitter is grounded.
In this case, if the pulse voltage Vp applied to the drive power supply line 31 is in a normal state of 24 V, for example, the NPN transistor Q20 is turned on, but a predetermined voltage according to the selection of the breakdown voltage of the Zener diode ZD, for example, When it becomes 16V or less, the NPN transistor Q20 is turned off. The potential state of the detection line 32 that varies depending on the on / off state of the NPN transistor Q20 is the low voltage detection signal Su.

The switch control unit 22 is provided with a disconnection corresponding part 22A and a low voltage corresponding part 22B.
First, the disconnection corresponding part 22A includes resistors R30 to R35, capacitors C30 to C33, and NPN transistors Q30 and Q31.
The potential divided by the resistors R30 and R31 with respect to the predetermined potential + B is supplied to the detection line 30 between the disconnection detectors 19A, 19B, and 19C and becomes the base voltage of the NPN transistor Q30. A capacitor C30 is connected between the base of the NPN transistor Q30 and the ground. The emitter of the NPN transistor Q30 is grounded.
A resistor R32 and a capacitor C31 are connected between the predetermined potential Vcc and the ground, and the connection point is connected to the collector of the NPN transistor Q30 via the resistor R33.
The connection point between the resistor R32 and the capacitor C31 is connected to the base of the NPN transistor Q31 via the resistor R34. A resistor R35 and capacitors C32 and C33 are connected between the base of the NPN transistor Q30 and the ground. The emitter of the NPN transistor Q30 is grounded, and the collector is connected to the above-described connection point TA (see the connection point TA in FIG. 3).

The low voltage corresponding unit 22B in the switch control unit 22 includes resistors R40 to R43, capacitors C40 to C42, and an NPN transistor Q40.
A resistor R41 and a capacitor C40 are connected between the predetermined potential Vcc and the ground, and the connection point is connected to the detection line 32 via the resistor R40.
The connection point between the resistor R41 and the capacitor C40 is connected to the base of the NPN transistor Q40 via the resistor R42. A resistor R43 and capacitors C41 and C42 are connected between the base and the ground of the NPN transistor Q40. The emitter of the NPN transistor Q40 is grounded, and the collector is connected to the above-described connection point TA (see the connection point TA in FIG. 3).

  In the above configuration, the switch control unit 22 controls the switch transistor Q10 of the power consumption switch unit 20 to be turned off when the disconnection is detected and when the low voltage state is detected, and the power consumption unit 21 The current supply to is turned off. Hereinafter, this operation will be described.

First, the operation according to the disconnection detection signal Sd will be described.
When none of the disconnection detectors 19A, 19B, and 19C detects a disconnection, that is, when a current normally flows through the light emitting element portions 17A, 17B, and 17C, the potential of the detection line 30 is shown in FIG. The potential is divided by the resistors R30 and R31. In this case, since the base current flows through the NPN transistor Q30 and the NPN transistor Q30 is in the ON state, the current from the predetermined potential Vcc flows from the resistor R33 → the NPN transistor Q30 → the ground. In this case, the NPN transistor Q31 cannot obtain a base current and is turned off, and the connection point TA is disconnected from the ground.
Therefore, in the power consumption switch section 20 of FIG. 3, the control transistor Q11 is turned on, and thereby the switch transistor Q10 is turned on. As a result, the power consuming unit 21 is connected to the drive power supply line 31, and a current flows through the dummy resistor r group.

If any one of the disconnection detectors 19A, 19B, and 19C is disconnected, the potential state of the detection line 30 is substantially at the ground level. In this case, the NPN transistor Q30 of the switch control unit 22 in FIG. 4 is turned off, and the current from the predetermined potential Vcc becomes the base current of the NPN transistor Q31 via the resistor R34, so that the NPN transistor Q31 is turned on. This creates a current path from the connection point TA to the ground.
Accordingly, in the power consuming switch unit 20 of FIG. 3, the control transistor Q11 is turned off, and thereby the switch transistor Q10 is turned off. Accordingly, the power consuming unit 21 is disconnected from the drive power supply line 31 and the current to the dummy resistor r group is turned off.
In this case, since the light emitting element portions 17A, 17B, and 17C remain connected to the drive power supply line 31, the light emitting operation is maintained in the light emitting element portion that is not disconnected.
Moreover, the amount of current flowing through the vehicular lamp 1 is reduced by turning off the current supply to the power consuming unit 21. When at least one of the light emitting element portions 17A, 17B, and 17C is disconnected and the power consuming portion 21 is disconnected from the driving power supply line 31, the vehicle-side control portion 2 has a predetermined output current for the vehicle lamp 1. The current value is less than Ic. For this reason, the vehicle side control part 2 shortens the period of the pulse voltage Vp according to the electric current fall about the said vehicle lamp 1 (pulse voltage Vp output of a 2nd frequency). As a result, the flashing light emission in the light emitting element portion capable of emitting light without disconnection is in a high flasher state.

Next, the operation according to the low voltage detection signal Su will be described.
When the pulse voltage Vp is not less than or equal to the predetermined voltage, the NPN transistor Q20 of the low voltage monitoring unit 16 in FIG. 4 is on. Therefore, the current from the predetermined potential Vcc flows through the resistor R40 → NPN transistor Q20 → ground. In this case, the NPN transistor Q40 cannot obtain a base current and is turned off, and the connection point TA is disconnected from the ground.
Therefore, in the power consumption switch section 20 of FIG. 3, the control transistor Q11 is turned on, and thereby the switch transistor Q10 is turned on. Accordingly, the power consuming unit 21 is connected to the drive power supply line 31 and a current flows through the dummy resistor r group.

When the pulse voltage Vp becomes equal to or lower than the predetermined voltage, the NPN transistor Q20 of the low voltage monitoring unit 16 in FIG. 4 is turned off. Therefore, the current from the predetermined potential Vcc becomes the base current of the NPN transistor Q40 via the resistor R42, so that the NPN transistor Q40 is turned on. This creates a current path from the connection point TA to the ground.
Therefore, in the power consumption switch unit 20 of FIG. 3, the control transistor Q11 is turned off, and the switch transistor Q10 is also turned off. As a result, the power consumption unit 21 is disconnected from the drive power supply line 31 and the current to the dummy resistor r group is turned off.

As can be seen from the above description, in the present embodiment, the first to third light emitting element portions 17A, 17B, and 17C each having a plurality of LEDs and connected in parallel with each other, The power consumption unit 21 connected in parallel with the light emitting element units 17A, 17B, and 17C, and the power consumption switch unit 20 that turns on / off the current supply to the power consumption unit 21 are provided. Also, first to third disconnection detectors 19A, 19B, and 19C that are provided corresponding to each of the first to third light emitting element units 17A, 17B, and 17C and detect disconnection of the corresponding light emitting element units, And a switch control unit 22 that controls the power consumption switch unit 20 to be turned off when a disconnection is detected by any one of the disconnection detection units 19A, 19B, and 19C.
Thereby, even if there is a disconnection in any of the light emitting element portions 17A, 17B, and 17C, the current supply to the power consuming portion 21 is stopped, but the power supply to the light emitting element portion is not stopped. That is, the light emitting element part which is not disconnected functions normally. For example, even if disconnection occurs in the light emitting element portion 17A, the light emitting operation of the light emitting element portions 17B and 17C is continued. Therefore, even when disconnection occurs in part, the light emitting function as the vehicular lamp 1 can be exhibited as much as possible.
In addition, by turning off the current supply to the power consumption unit 21, the amount of current flowing through the vehicular lamp 1 is reduced. As described above, the current values Iin1, Iin2, Iin3 and the power consuming unit 2 consumed in each system of the first to third light emitting element units 17A, 17B, and 17C so as to satisfy Ids <Ic <(Idal + Ir). The vehicle-side control unit 2 (see FIG. 1) shortens the cycle of the pulse voltage Vp in accordance with the current decrease for the vehicle lamp 1. As a result, the flashing light emission in the light emitting element portion capable of emitting light is in a high flasher state. Accordingly, the driver or the like can recognize an abnormality caused by disconnection or the like. That is, in the present embodiment, the flashing light emission can be continued as much as possible after the abnormality notification function is exhibited.

The power consumption switch unit 20 is connected in series with the power consumption unit 21, and the series connection of the power consumption switch unit 20 and the power consumption unit 21 is connected in parallel with the light emitting element units 17A, 17B, and 17C. Thus, a configuration in which the current on / off only for the power consuming unit by the power consuming switch unit 21 is specifically realized.
Each of the light emitting element portions 17A, 17B, and 17C includes a plurality of semiconductor light emitting elements (LEDs) connected in series. For this reason, although the light emitting element part which a disconnection generate | occur | produced becomes impossible to light, in other light emitting element parts, light emission operation | movement with sufficient light quantity by the serial connection of several LED is performed.

  The vehicular lamp 1 of the present embodiment is desirably used as a turn signal lamp. This is because the configuration including the power consumption unit 21 consumes power in addition to the light emitting operation, but unnecessary power consumption is reduced if the turn signal lamp has a short lighting time. In addition, when the wire is disconnected, it blinks at a high speed because the function as a turn signal lamp that blinks and emits light is not impaired.

In the present embodiment, the switch control unit 22 controls the power consumption switch unit 20 to be turned off when the low voltage monitoring unit 16 detects that the input voltage (Vp) is equal to or lower than a predetermined voltage. . That is, when the voltage (Vp) supplied for light emission driving decreases, the load is reduced by disconnecting the power consuming unit 21, and the driving current to each LED of the light emitting element units 17A, 17B, and 17C is secured. be able to. Therefore, even if a certain low voltage state occurs, the light emission operation can be maintained.
Further, although the light emitting element portions 17A, 17B, and 17C are arranged in parallel, when a plurality of light emitting elements are used for the convenience of the amount of emitted light, a plurality of light emitting element portions are connected in parallel to each other so that one series system is provided. The forward voltage (Vf) at can be made not to become too large. Thereby, the range of the low voltage which can be light-emitted can be expanded.

  In the present embodiment, the power consumption unit 21 is continuously supplied with current supplied to the light emitting element units 17A, 17B, and 17C corresponding to both the case where the disconnection occurs and the case where the low voltage state occurs. Although the current supply is turned off, a configuration for realizing such an operation can be realized with an efficient circuit configuration using the switch control unit 22 and the power consumption switch unit 20.

Although the embodiments have been described above, various modifications corresponding to the present invention can be considered.
For example, the power consuming unit 21 is a dummy load circuit using a dummy resistor r, but other than this, a circuit using other passive elements or active elements, a circuit imitating the current-voltage characteristics of an incandescent lamp, and not a dummy. It may be a circuit unit having some other operation function.
Moreover, the number of n as a 1st-nth light emitting element part is not restricted to three. n may be 2 or more. Further, the number of LEDs constituting the light emitting element portion may not be plural but one.
The present invention is also suitable for application to lamps other than turn signal lamps, such as tail lamps and stop lamps.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle lamp, 16 ... Low voltage monitoring part, 17A, 17B, 17C ... Light emitting element part, 19A, 19B, 19C ... Disconnection detection part, 20 ... Power consumption switch part, 21 ... Power consumption part, 22 ... Switch Control unit

Claims (4)

When n is an integer greater than or equal to 2, each of the first to nth light emitting element portions each having one or a plurality of semiconductor light emitting elements and connected in parallel with each other;
A power consuming unit connected in parallel with the plurality of light emitting element units;
A power consuming switch unit for turning on / off current supply to the power consuming unit;
A first to n-th disconnection detection unit that is provided corresponding to each of the first to n-th light-emitting element units and detects disconnection of the corresponding light-emitting element unit;
A switch control unit that controls the power consumption switch unit to be turned off when a disconnection is detected by any of the first to nth disconnection detection units;
Vehicular lamp equipped with The power consumption switch unit is connected in series with the power consumption unit,
The vehicular lamp according to claim 1, wherein a series connection of the power consuming switch unit and the power consuming unit is connected in parallel to the first to nth light emitting element units. The vehicular lamp according to claim 1, wherein each of the first to nth light emitting element units is configured by connecting a plurality of semiconductor light emitting elements in series. The first to nth light emitting element units constitute a turn signal lamp for a vehicle, and the first to nth light emitting element units emit flashing light by receiving a pulse voltage supplied from a vehicle side control unit. A vehicle lamp to perform,
When the vehicle-side controller supplies a pulse voltage of the first frequency to the vehicle lamp when the output current to the vehicle lamp is equal to or greater than a predetermined current value, and the output current to the vehicle lamp is less than the predetermined current value When a pulse voltage having a second frequency higher than the first frequency is supplied to the vehicular lamp,
For the input current supplied from the vehicle-side control unit, Idal is the sum of the input currents consumed by the n light emitting systems related to the first to nth light emitting element units, and the input current is consumed by the power consuming unit. Ir, the sum of input currents consumed by the remaining (n-1) light emitting systems when a disconnection occurs in one of the n light emitting systems of the first to nth light emitting element units. Let Ids be the maximum value as
Ids <predetermined current value <(Idal + Ir)
The vehicle lamp according to any one of claims 1 to 3, wherein:

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