JP2003341425A - Lighting circuit of lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a pseudo lighting state in a lighting system composed of LEDs, in a lighting circuit having a structure for detecting electrical connection in the lighting system by carrying a fine current to the lighting system to detect the fine current. <P>SOLUTION: This lighting circuit is provided with: the lighting system 4 using the LEDs 411 as a light source; and a main lighting circuit 3 for feeding predetermined power to the LEDs to light them. The lighting circuit 3 is equipped with: a means for feeding fine power lower than the predetermined power to the lighting system; and monitor parts 304 and 305 for monitoring the connection of the lighting system 4 to the lighting circuit 3 by detecting that a fine current Id caused by the fine power is carried to the lighting system. A lighting sub-circuit 5 provided with a switch means SW for detecting the power fed to the lighting system to stop the feed of the power to the LEDs 411 in detecting the fine power and to allow the feed of power to the LEDs in detecting the predetermined power is connected to the lighting system 4 side. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting circuit having a monitor circuit for monitoring the lighting state of a lighting device, and more particularly to a lighting circuit using LEDs in the lighting device.

[0002]

2. Description of the Related Art In recent years, LEDs (light emitting diodes) have been used as a light source for lighting devices used as lamps for vehicles such as automobiles.
Is used to effectively reduce the thickness and weight of the lighting device. On the other hand, in terms of the brightness of the lighting device using the LED, the lighting device using the incandescent lamp as the light source is still used. Such an LED and an incandescent light bulb lighting device each have their own lighting circuit, but depending on the type of vehicle, a lighting circuit applicable to both the LED and incandescent light bulb lighting device may be required. . For example,
In a vehicle that consists of a tractor as a driving vehicle and a trailer as a driven vehicle towed by the tractor, the trailer is replaced and towed.Therefore, rear lamps such as tail lamps and stop lamps equipped on the trailer are installed. When some trailers are configured with LEDs and some other trailers are configured with incandescent light bulbs, it is necessary to suitably light each rear lamp when the trailers are exchanged and towed.

An example of a lighting circuit in a conventional tractor and a trailer using an incandescent lamp as a rear lamp will be described with reference to FIG. The tail lamp TL and the stop lamp SL of the rear lamp 8 of the incandescent bulb of the trailer 1 are incandescent bulbs. The tractor 1 has a lighting circuit 3
Are provided, and both are connected via a connector 7. The connector 7 has a stop lamp terminal T
A GND terminal TG and a tail lamp terminal TT connected to S and GND (ground) are provided. The lighting circuit 3 includes a vehicle-mounted power source E as a power source for lighting the incandescent light bulb rear lamp 8, a tail lamp switch 301 for lighting the tail lamp TL, and a brake not shown in the figure for lighting the stop lamp SL. The lighting circuit 3 is provided between the brake switch 303 interlocked with the pedal and the tractor 1 and the trailer 2, and the incandescent lamp rear lamp 8 is provided.
In order to confirm that the stop lamp SL is electrically connected to the vehicle, a monitor lamp 304 for monitoring that the vehicle-mounted power source E is connected to the stop lamp SL, and a monitor for controlling lighting of the monitor lamp 304 And section 305. The brake switch 303 has a common contact SS connected to a stop lamp terminal TS of the connector 7 and a power supply side contact ES connected to a power supply E and the monitor unit 30.
The relay switch is configured to be switchable to the monitor-side terminal MS connected to the switch 5, and is configured as a relay switch that is switched by the brake pedal switch 302 that is turned on when a brake pedal (not shown) is operated.
The monitor unit 305 lights the monitor lamp 304 when the stop lamp SL is connected to the lighting circuit 3 by detecting the current Id flowing through the resistor R0 interposed between the power source E and the monitor side contact MS. It is what makes me.

In the lighting circuit 3, the common contact SS of the brake switch 303 is used when the brake operation is not performed.
Is connected to the monitor side contact MS. Therefore, power supply E-resistance R0-brake switch 303-connector 7-
Since the route of the stop lamp SL-GND is configured,
In this path, a minute current Id generated by the resistor R0
Flow through. This current is, for example, about 6 mA,
This current does not cause the incandescent light bulb constituting the stop lamp SL to be in a visually lit state. Then, the monitor unit 305 detects this minute current Id, and turns on the monitor lamp 304 when it detects it. Thus, the driver of the tractor 1 can confirm that the stop lamp SL is electrically connected to the lighting circuit 3 of the tractor 1 by lighting the monitor lamp 304. Further, when the brake is operated, the brake switch 303 has the common contact S
Since S is switched to the contact ES on the power supply side, the incandescent light bulb of the stop lamp SL is lit with regular brightness, and the brake operation is displayed on the following vehicle. The tail lamp T can be turned on by turning on the tail lamp switch 301 during nighttime driving.
Although the L incandescent light bulb is turned on, if the brake operation is performed in this state, the stop lamp SL is also turned on, so that the brightness of the incandescent light bulb rear lamp 8 as a whole is increased and the brake operation is displayed on the following vehicle. Is possible.

[0005]

In such a conventional lighting circuit, as shown in FIG. 9, a rear lamp is composed of an LED 901 as a stop lamp SL, an LED 902 as a tail lamp TL, and a drive resistor R of each LED. L
It is assumed that the trailer having the ED rear lamp 9 is connected.
In this case, when the brake operation is not performed, the brake switch 303 is provided in the lighting circuit 3 of the tractor 1.
Since the common contact SS is connected to the monitor-side contact MS, the power source E-resistance R0 is the same as in the case of the incandescent lamp rear lamp.
-Brake switch 303-Drive resistance R-LED901
A GND circuit is configured, a minute current Id flows through this circuit, and a minute current Id flows through the LED 901. Therefore, in the lighting circuit 3, L by the monitor lamp 304
Checking the connection state of the ED rear lamp 9 is the same as the case of the incandescent light bulb rear lamp 8, but the stop lamp S
The LED 901 as L is emitted by the minute current Id though it is weak, and the so-called stop lamp SL is in a pseudo lighting state. In particular, in this type of LED rear lamp 9, since a large number of LEDs are arranged in a plane, even if the individual LEDs are pseudo-lighted, the total amount of light of the stop lamp SL increases,
When viewed from the following vehicle, an unfavorable situation may occur in which the stop lamp SL is erroneously determined to be lit.

An object of the present invention is to provide a lighting circuit capable of eliminating a pseudo lighting state in a lighting device composed of LEDs.

[0007]

The lighting circuit of the present invention is L
A lighting device that uses the ED as a light source, and a main lighting circuit that supplies predetermined power to the LEDs to turn on the LEDs, and the main lighting circuit includes means for supplying minute power lower than the predetermined power to the lighting device. The lighting device includes a monitor unit that detects that a minute current accompanying the minute power is flowing to the lighting device and monitors that the lighting device is connected to the main lighting circuit. A sub-lighting circuit including a switch means that detects the supplied power, stops the power supply to the LED when a very small power is detected, and enables the power supply to the LED when a predetermined power is detected. It is characterized by being connected.

In the lighting circuit of the present invention, the tractor is provided with a main lighting circuit, and the trailer pulled by the tractor is provided with a rear lamp lit by the main lighting circuit. The main lighting circuit, which is composed of LEDs, has means for passing a predetermined amount of electric power to the rear lamp to turn on the LED, means for supplying a minute amount of electric power lower than the prescribed amount of electric power to the rear lamp, and a minute current accompanying the minute amount of electric power. The rear lamp is equipped with a monitor that detects that it is flowing through the rear lamp and monitors that the rear lamp is connected to the main lighting circuit.The rear lamp detects the power supplied to the rear lamp and detects minute power. It stops the power supply to the LED when it does, and it can supply the power to the LED when a predetermined power is detected. Sub lighting circuit comprising a switching means for, characterized in that is connected.

Here, in the present invention, the sub lighting circuit is preferably formed integrally with the lighting device or the rear lamp, but it may be formed separately.

According to the present invention, even when a minute current for monitoring the connection state of the lighting device in the main lighting circuit is flowing through the lighting device, the sub-lighting circuit detects the minute current and the switching means. By turning off, the minute current does not flow through the LED of the lighting device, and the LED does not light up slightly. With this, it is possible to monitor the connection state of the lighting device and prevent the LEDs of the lighting device from being pseudo-lighted, so that a highly reliable lighting device can be obtained.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual configuration diagram of an embodiment in which the present invention is applied to a rear lamp of a trailer towed by a tractor as in the case described with reference to FIG.
The tractor 1 is equipped with a lighting circuit 3 on the tractor side as shown in FIG. 8, and the trailer 2 towed by the tractor 1 is equipped with a rear lamp 4 using an LED as a light source.
The rear lamp 4 is integrally provided with a trailer lighting circuit 5. In the present specification, the lighting circuit 3 provided in the tractor 1 is referred to as a main lighting circuit, and the lighting circuit 5 of the rear lamp 4 provided in the trailer 2 is referred to as a sub lighting circuit. The main lighting circuit 3 and the sub lighting circuit 5 are electrically connected to each other via the wiring 6 and the connector 7.

FIG. 2 is an exploded perspective view of a part of the rear lamp 4. The rear lamps 4 are, here, lamp chambers 402, 403 arranged in two rows in front of a lamp body 401.
Reflectors 404 and 405 are arranged in the interior, respectively, and lenses 40 and 40 are provided in front of the lamp chambers 402 and 403, respectively.
6 and 407 are attached to each light chamber 40.
A large number of LEDs 410 and 411 in 2,403 respectively
LED substrates 408 and 409, which are arranged in a plane, are installed. In this embodiment, the rear lamp 4
Is originally configured by using a rear lamp that uses an incandescent lamp as a light source, and LED lamps 408 and 408 are installed in the lamp chambers 402 and 403 instead of the incandescent lamp, respectively, and thus the rear lamp for the LED is installed. The example shown in FIG. Then, here, the LED board 408 in which the yellow light color LED 410 is arranged is provided inside one of the lamp chambers 402, and is configured as a turn signal lamp TSL,
In the other lamp chamber 403, an LED board 409 in which red-light color LEDs 411 are arranged is installed and configured as a tail & stop lamp T & SL.

FIG. 3 shows the tail and stop lamp T & S.
It is a circuit diagram of the sub lighting circuit 51 of 1st Embodiment of the sub lighting circuit 5 for lighting L. Many red light LE
A plurality of D411 connected in series is connected in parallel to form a light emitting portion 501 as the rear lamp 4, but here, for convenience, six LEDs 41 are provided.
It shows a case where ones connected in series are connected in two rows in parallel. The cathode side of each LED row is the GND of the connector 72 that constitutes one of the connectors 7.
It is connected to the (ground) terminal TG, and the anode side is connected to the connector 7 via tail lamp driving resistors R1 and R2, respectively.
Connected to the tail lamp terminal TT of. Further, on the anode side, a FET (field effect transistor) that constitutes the switching element SW via the stop lamp driving resistors R3 and R4, here a P-channel type MOSFET 502.
Connected to the drain of. This MOSFET 502
Is the stop lamp terminal TS of the connector 72.
It is connected to the. Further, a load resistor R5 for flowing a minute current is connected between the stop lamp terminal TS and the GND terminal TG of the connector 72, and the voltage across the load resistor R5, that is, the stop lamp terminal TS. Voltage dividing resistors R6 and R7 connected in series are connected to divide the voltage between the GND terminal TG and the voltage Vd divided by the voltage dividing resistors R6 and R7 is applied to the gate of the MOSFET 502. I am letting you.

The tail and stop lamp T & SL thus constructed is connected to the connector 71 of the main lighting circuit 3 of the tractor shown in FIG. 8 via the connector 72. That is, FIG. 4 shows a circuit configuration in which the main lighting circuit 3 is connected to the sub lighting circuit 51 of the tail & stop lamp T & SL of FIG. This main lighting circuit 3
As described above, the vehicle-mounted power source E, the tail lamp switch 301 for lighting each LED 411 of the light emitting section 501 as a tail lamp, the brake switch 303 for lighting the LED 411 as a stop lamp, and the tractor 1 as described above. A monitor lamp 304 for monitoring that a vehicle-mounted power source is connected to the rear lamp 4 in order to confirm that the lighting circuit with the trailer 2 is electrically connected, and the monitor lamp 304. Is connected to the tail & stop lamp T & SL by a connector 71 forming the other side of the connector 7.
The brake switch 303 includes a common contact SS connected to the stop lamp terminal TS of the connector 71, a contact ES connected to the power source E, and a contact MS connected to the monitor unit 305.
And a relay switch which is switched by a brake pedal switch 302 which is turned on when a brake pedal of the tractor 1 which is not shown in the figure is operated. The monitor unit 305 detects the minute current Id flowing through the resistor R0 interposed between the power source E and the monitor-side contact MS to connect the tail & stop lamp T & SL to the main lighting circuit 3 of the tractor 1. The monitor lamp 304 is sometimes turned on.

According to the main lighting circuit 3 and the sub lighting circuit 5 of this structure, when the brake operation is not performed, the brake switch 303 has the common contact SS connected to the monitor side contact MS and is set by the resistor R0. The minute current Id generated is the stop lamp terminal TS of the connector 7.
Applied to. This applied minute current Id is tail &
The current is passed through the load resistor R5 of the stop lamp T & SL, and the voltage across the load resistor R5 is divided into resistors R6, R.
The voltage Vd divided by 7 is input to the gate of the MOSFET 502. This voltage is the stop lamp terminal TS
Therefore, the P-channel MOSFET 502 is turned off because it becomes a small negative voltage. Therefore, the minute current Id applied to the stop lamp terminal TS is MO
Each LED 41 is blocked by the SFET 502.
No one is applied to the anode of each LED 411
A minute current Id does not flow to the light emitting section 501 and the light emitting section 501 is not turned on.

On the other hand, when the brake contact is performed and the common contact SS of the brake switch 303 is switched to the contact ES on the power source side, the predetermined voltage of the vehicle-mounted power source E is supplied through the stop lamp terminal TS of the connector 7 to the tail & stop lamp T & S.
Applied to L. This predetermined voltage is divided by the voltage dividing resistors R6 and R7, and the divided voltage Vd is the MOSFET 50.
The divided voltage Vd is input to the gate of the MOSFET 2. However, the divided voltage Vd becomes a negative voltage higher than a predetermined level with respect to the predetermined voltage as compared with the voltage when the minute current is divided.
02 is turned on. As a result, the predetermined voltage of the stop lamp terminal TS flows through the stop lamp drive resistors R3 and R4 through the MOSFET 502 and is passed to each LED 411 to turn on each LED 411. As a result, the light emitting unit 501 is turned on with regular brightness, and the brake operation is displayed on the following vehicle.

When the vehicle is running at night, the tail lamp switch 301 is turned on to apply a predetermined voltage of the vehicle-mounted power source E to the tail lamp driving resistors R1 and R2 through the tail lamp terminal TT of the connector 7, and a required current flows through each LED 411. Therefore, each LED 411 is turned on and functions as a tail lamp for the following vehicle. Further, even in this state, when the brake operation is not performed, only the minute current Id flows through the stop lamp terminal TS, so that the MOSFET 502 is in the off state, and the minute current Id flows through the LED 411. There is no such thing. Further, when the brake operation is performed while the tail lamp switch 301 is in the on state, a predetermined voltage of the vehicle-mounted power source E is applied to the stop lamp terminal TS of the connector 7 and the MOSFET 502 is turned on as described above. A current flows through each LED 411 in a state of being overlapped, and the current flowing through each LED 411 is increased, the overall brightness of the tail & stop lamps T & SL is increased, and the braking operation can be displayed on the following vehicle. Become.

As described above, the tail and stop lamp T
A small current flows from the main lighting circuit 3 of the tractor 1 to the tail & stop lamps T & SL when & SL is not lit.
Is lit, and the normal electrical connection state to the tail & stop lamp T & SL can be confirmed. On the other hand, in the sub lighting circuit 51 of the trailer 2, the MOSFET 502 is not turned off and the minute current Id does not flow to the LED 411 when the minute current Id is flowing.
The LED 411 does not light up slightly, and there is no erroneous display of the brake operation for the following vehicle. Whether the tail & stop lamp T & SL is turned on as a tail lamp or not, the LED 411 is turned on as a stop lamp by a brake operation or the brightness at the time of lighting is increased to perform the same brake operation as before. Is displayed as described above.

Next, circuit examples of different embodiments of the present invention will be described. In each of the following embodiments, the case where the tail and stop lamp as in the first embodiment is applied will be described. In the following description, the same parts as those in the first embodiment are designated by the same reference numerals. FIG. 5 is a circuit diagram of a lighting circuit according to the second embodiment, in which the sub lighting circuit 5 for the tail & stop lamp T & SL is shown.
In Fig. 2, a load resistor R5 for flowing a minute current Id is connected in series with the voltage dividing resistors R6 and R7. In addition,
Here, for the sake of explanation, one of the load resistor R5 and the voltage dividing resistor R
Although an example in which 7 and 7 are different resistors is shown, one of the voltage dividing resistors R7 may also be used as the load resistor R5.

In the sub lighting circuit 52 of the second embodiment, the minute current Id is divided into the voltage dividing resistors R6 and R7 and the load resistor R5.
Flows over the small current Id and each resistance R
It is possible to keep the MOSFET 502 in an off state by using the voltage Vd obtained by 5, 5, R6 and R7 and prevent the LED 411 from being pseudo-lit by the minute current Id. Further, when the voltage of the vehicle-mounted power source E is applied to the stop lamp terminal TS, the divided voltage Vd obtained by the resistors R5, R6 and R7.
As the MOSFET 502 is turned on by the LE, the LE lamp is used as a stop lamp as in the first embodiment.
D411 is turned on. As shown in FIG. 5, when the load resistance R5 and the voltage dividing resistances R6 and R7 are connected in series, the effect of reducing the number of parts cannot be obtained, but the load resistance R
When 5 is used as one of the voltage dividing resistors R7, the effect of reducing the number of parts can be obtained.

FIG. 6 shows the sub lighting circuit 53 of the third embodiment.
3 is a circuit diagram of the small current Id in each of the embodiments.
In this example, the load resistor R5 flowing through and one of the voltage dividing resistors R7 are constituted by variable resistors VR5 and VR7, respectively. That is, when the value of the minute current Id generated in the main lighting circuit 3 provided in the tractor 1 is different for each tractor or each main lighting circuit, or when there is a variation, the tail of the trailer 2 is & If the voltage Vd divided in the sub-lighting circuit 5 of the stop lamp T & SL is different due to the fluctuation or change of the minute current Id, the on / off state of the MOSFET 502 cannot be controlled properly, and in some cases, The voltage Vd obtained by the minute current Id increases and MO
There is a case where the SFET 502 is turned on and the LED 411 is pseudo-lighted. In this case, the variable resistors VR5,
By adjusting each resistance value of one of the load resistance and the voltage dividing resistance by VR7, the MOSFET 502 can be surely turned off even if the minute current Id in the main lighting circuit 3 is different, and pseudo lighting is prevented in advance. It will be possible. Also in this embodiment, one variable resistor may be configured to serve as one of the voltage dividing resistors and the load resistor, which is effective in reducing the number of parts.

FIG. 7 shows a sub lighting circuit 54 of the fourth embodiment.
FIG. 4 is a circuit diagram of the example, which is an example using a relay switch as a switching element. That is, the relay coil 511 of the relay switch 510 is connected between the stop lamp terminal TS of the connector 72 and the GND terminal TG, and the common contact S0 of the relay contacts 512 is connected to the stop lamp terminal TS.
In addition, one switching contact S1 is connected to the load resistor R5, and the other switching contact S2 is connected to the LED 411 via the stop lamp drive resistors R3 and R4. The relay switch 510 includes a relay coil 5 when a minute current Id is flowing through the stop lamp terminal TS.
11 is de-excited so that the common contact S0 becomes one of the switching contacts S
1 and connect the stop lap terminal TS to the in-vehicle power supply E
When the required voltage is applied, the common contact S0 is connected to the other switching contact S1 by exciting the relay coil 511.

In the fourth embodiment, when the minute current Id is passed from the main lighting circuit 3 to the stop lamp terminal TS of the connector 72, the relay coil 511 is not excited and the relay contact 512 has the common contact S0. Of the main lighting circuit 3 of the tractor 1 because the minute current Id flows through the load resistance R5 by connecting to the switching contact S1 of
5, the monitor lamp 304 is turned on and the connection is confirmed. At this time, depending on the switching state of the relay contact 512,
The minute current Id does not flow through the stop lamp drive resistors R3 and R4 or the LED 411, and the pseudo lighting of the LED 411 is prevented. On the other hand, when the required voltage of the vehicle-mounted power source E is applied to the stop lamp terminal TS of the connector 72 by the brake operation, the relay coil 511 is excited and the common contact S0 of the relay contacts 512 is connected to the other switching contact S2, and the required voltage is increased. Are stop lamp drive resistors R4 and R5
To the LED 411, and the LED 411 is turned on. At this time, since the required voltage is not applied to the load resistor R5 due to the switching state of the relay contact 512, an excessive current does not flow in the load resistor R5,
The power consumption is suppressed and the load resistor R5 is not burned out.

Here, in the above embodiment, the LED is detected by detecting a minute current in the tail & stop lamp T & SL.
An example is shown in which the sub-lighting circuit 5 that turns off the power supply to the terminal 411 is configured integrally with the tail & stop lamp T & SL, but the sub-lighting circuit 5 is provided between the main lighting circuit 3 and the tail & stop lamp T & SL. As long as it is inserted, for example, on the wiring 6 between the connector 7 for electrically connecting the tractor 1 and the trailer 2 and the tail & stop lamp T & SL, the tail & stop lamp T & SL is provided.
It may be configured separately from.

Further, in each of the above-mentioned embodiments, the LED and the stop lamp are respectively lit as the tail lamp and the stop lamp, but the tail lamp and the stop lamp are different from each other.
It is also possible to configure it as a lamp in which D is turned on. Needless to say, the number of LEDs constituting the lamp and the configuration of series connection and parallel connection can be appropriately changed.

Further, the illumination device according to the present invention is not limited to the tail & stop lamp of the above embodiment. Further, the present invention is not limited to a lighting circuit as a vehicle lamp including a tractor and a trailer, and the present invention can be similarly applied to any lighting circuit configured to monitor a state of a lighting device by passing a minute current. Needless to say. Furthermore, the present invention can be configured so that a minute voltage is generated in the main lighting circuit, a minute current generated by applying the minute voltage to the lighting device is detected, and the connection of the lighting device is confirmed. Needless to say.

[0027]

As described above, according to the present invention, even when a minute current for monitoring the connection state of the lighting device in the main lighting circuit is passed through the lighting device, the minute current is supplied to the sub lighting circuit. By detecting and turning off the switching means, the minute current does not flow through the LED of the lighting device, and the LED does not light up slightly. With this, it is possible to monitor the connection state of the lighting device and prevent the LEDs of the lighting device from being pseudo-lighted, so that a highly reliable lighting device can be obtained. In particular, the present invention applies to tractor and trailer tails and
When applied as a vehicle lamp such as a stop lamp, when the stop lamp is not lit, a small current flows from the main lighting circuit of the tractor to the stop lamp, so that the monitor lamp is lit in the tractor and the stop lamp is lit. A normal electrical connection to the LED can be confirmed. On the other hand, in the sub-lighting circuit, the switch means is turned off when the minute current is flowing, so that the minute current does not flow to the LED. Does not light up slightly due to a small current, and the effect that the brake operation for the following vehicle is not erroneously displayed is obtained.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram of an embodiment in which the present invention is applied to a rear lamp of a tractor / trailer.

FIG. 2 is a partially exploded perspective view of an example of a rear lamp.

FIG. 3 is a circuit diagram of a sub lighting circuit according to the first embodiment of the present invention.

FIG. 4 is a circuit diagram for explaining an operation of the sub lighting circuit of the first embodiment connected to a main lighting circuit.

FIG. 5 is a circuit diagram of a sub lighting circuit according to a second embodiment of the present invention.

FIG. 6 is a circuit diagram of a sub lighting circuit according to a third embodiment of the present invention.

FIG. 7 is a circuit diagram of a sub lighting circuit according to a fourth embodiment of the present invention.

FIG. 8 is a circuit diagram of an example of a conventional lighting circuit.

FIG. 9 is a circuit diagram for explaining a problem when a conventional lighting circuit is applied to an LED lighting device.

[Explanation of symbols]

1 tractor 2 trailers 3 Main lighting circuit 4 rear lamp 5 (51-54) Sub lighting circuit 6 wiring 7 (71, 72) connector 8 incandescent light bulb rear lamp 9 LED rear lamp 401 light body 402,403 Light room 408,409 LED substrate 410,411 LED 501 light emitting part 502 MOSFET (switching element) 510 relay switch R1, R2 tail lamp drive resistance R3, R4 Stop lamp drive resistance R5 load resistance R6, R7 partial pressure resistance VR5, VR7 variable resistor

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3K039 LA03 LB05 LC05 LD06 MA05                 3K073 AA13 AA39 AA49 AA50 AA76                       AA92 BA09 CE15 CF06 CF10                       CJ08 CJ17

Claims (3)

[Claims] 1. An illumination device using an LED as a light source, and the L
A main lighting circuit for supplying a predetermined power to the ED to turn it on, a means for supplying a minute power lower than the predetermined power to the lighting device to the main lighting circuit, and a minute current accompanying the minute power. Is supplied to the lighting device. The monitoring device detects that the lighting device is flowing through the lighting device and monitors that the lighting device is connected to the main lighting circuit. When the electric power is detected, the supply of the electric power to the LED is stopped when the minute electric power is detected, and when the predetermined electric power is detected, the L
A lighting circuit for a lighting device, to which a sub-lighting circuit including a switch means that enables supply of electric power to the ED is connected. 2. The tractor is provided with a main lighting circuit,
In a vehicle lighting device in which a trailer towed by the tractor is provided with a rear lamp lit by the main lighting circuit, the rear lamp of the trailer is an LED.
In the main lighting circuit, means for passing a predetermined electric power to the rear lamp to turn on the LED, means for supplying a minute electric power lower than the predetermined electric power to the rear lamp, and the minute electric power Is provided with a monitor unit that detects that a minute current is flowing through the rear lamp and monitors whether the rear lamp is connected to the main lighting circuit. The rear lamp is supplied to the rear lamp. A sub-lighting circuit is connected which detects electric power and stops the supply to the LED when the minute electric power is detected, and enables the supply to the LED when the predetermined electric power is detected. A lighting circuit for a lighting device, which is characterized in that 3. The lighting circuit for a lighting device according to claim 1, wherein the sub lighting circuit is formed integrally with the lighting device or the rear lamp.