JPH08315613A - Dimmer control circuit of headlamp of car - Google Patents

Abstract

PURPOSE: To improve the operability and reliability of a flashing function which suggests manual operations by providing a manually operated dimmer, and when a vehicle is turning or passing other vehicle, allowing light to be flashed manually to the other vehicle. CONSTITUTION: When a vehicle is in a passing or turning condition and a headlamp is blinked to signal a vehicle approaching its front, operational amplifiers U4, U5, U6 are actuated to operate a manually operated dimming switch; that is, in an automatic weak light mode, switching of the manually operated switch from strong light to weak light interrupts a power supply circuit to discharge a capacitor C3 through a diode D2 and to discharge a capacitor C4 via R24, R26. When the manually operated switch is reset in a position for strong light, the power supply is restored, and when a normal rectangular signal is fed to a triode BG1 via the operational amplifiers U3, U5, U6, the triode BG1 becomes conducting and allows the headlight to produce signals suggesting strong and weak light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimmer control circuit for an automobile headlight.

[0002]

BACKGROUND OF THE INVENTION A control circuit is the heart of a dimmer in a vehicle, where it is generated by a photoelectric probe for transmission to subsequent control circuits such as amplification, filtering, shaping, delay and comparison. An electrical signal, a relatively clear signal, is obtained to determine the switching between "strong light" and "weak light", and the mode switching drive signal is applied to the control line CT.
To the actuating relay, which is amplified by the relay to drive the relay into actuation and automatically controls the headlights to switch between "strong light" and "weak light".

[0003]

A problem with the dimming control circuits currently in use is the inability to alter the light for approaching vehicles due to the lack of a flash that is indicative of human operation. For example, Chinese Patent No. 872006
No. 73U "Automatic dimmer controller that improves driving safety" does not have a flash that implies human operation.

Still another problem is that since the controller circuit is composed of individual elements that are adjacent to each other, it takes a lot of time to assemble due to the large number of components and the welding contacts. Bulky manufacturing is expensive and unreliable in transportation. SUMMARY OF THE INVENTION It is an object of the invention to provide a technical solution for a controller circuit with improved maneuverability reliability with a flash which is indicative of human operation.

[0005]

The control circuit proposed in the present invention includes a signal input circuit, a non-inverting amplifier circuit, an inverting amplifier circuit, a low-pass filter, a voltage dividing circuit, a Schmitt circuit, a rectangular wave generator, and a voltage comparison circuit. And an output circuit, the diode D7, the capacitor C8 and the resistor R3 constitute the input circuit, the operational amplifiers U1, R1 and R4 constitute an in-phase amplifier, and the resistors R5, R6, R7 and R2 and the operational amplifier U2. Is the inverting amplifier circuit, and includes resistors R10 and R12.
And C5 form the low pass filter, and resistors R8, R
9, R13 and R25 constitute the voltage dividing circuit,
The resistors R11, R14 and the operational amplifier U3 form a Schmitt circuit, the C3, D2, R18, R19, R20 and the operational amplifier U4 form the rectangular wave generator, and the capacitor C7, the resistors R21, R22, R23 and the capacitor C4. , The resistor R24 and the operational amplifier U5 constitute a second-stage Schmitt circuit, and the resistors R25, R26 and the operational amplifier U6 constitute a voltage comparator, and the triode BG1,
The resistor R27 and the diode D4 are the signal line CT of the relay.
And an output circuit connected to.

[0006]

[Operation] When the mode switching signal is received from the control circuit, the relay amplifies the signal to keep the relay in the operating state, and the vehicle headlamp automatically switches between "strong light" and "weak light". Control to switch. An additional function of the relay is to disconnect the power circuit to interrupt the operation of the controller and discontinue the automatic operation when the manual switch is set to the "low light" position. In order to ensure the stable operation of the controller, the control circuit according to the present invention is formed in the IC of the thick film circuit block and includes four capacitors C3, C4, C5 and C8 and two debacking resistors R1 and R2. All other elements are integrated into the IC block, except that the overall dimensions do not exceed 30mm x 20mm U1 (5), U1 (6),
U2 (10), U2 (8), U1 (4), D1 (5),
It is composed of U4 (6), U5 (10), D4 (+1) and the first to tenth 10-pins to the ground, respectively.

[0007]

The present invention will be described in detail below with reference to the drawings. In FIG. 1, the dotted frame indicates the IC part. The thick film circuit portion includes the input circuits D7, C8, R3 and the operational amplifier U1,
Non-inverting amplifier consisting of R1 and R4; R5, R6, R
Inverting amplifier consisting of 7, R ₂ and operational amplifier U2; R
C9 which consists of 10, R12 and C5 and quadratures the high frequency signal
Low pass filter with R8, R9, R13 and R25
A voltage divider for applying a reference voltage to operational amplifiers U3, U4 and U6; a Schmitt circuit composed of R11, R14 and operational amplifier U3; C3, D2, R1
Schmitt circuit composed of 8, R19, R20 and operational amplifier U4; C7, R21, R22, R23, C
4, a Schmitt circuit composed of R24 and an operational amplifier U5, a voltage comparator composed of R25, R26 and U6; and an output circuit composed of triodes BG1 and R27 and a diode D4.

Next, the operating principle of the entire block of the thick film circuit will be briefly described. When driving the vehicle with a safety controller in automatic operation mode, i.e. when connected to a corresponding power supply, the photoelectric probe outputs a minimum current when the vehicle is not approaching the front and the vehicle is in front. When approaching, a large current is output and then the output current is reduced again. The process of switching the automatic switching to the low light when another vehicle approaches is as follows. That is, the opto-electrical probe outputs a positive "step" signal which is in turn amplified by operational amplifiers U1 and U2 which convert the signal to a phase of opposite polarity which is then fed to a thick film controller and then generated. Possible unwanted high frequency noise is removed by a low pass filter consisting of R10, R12 and C5, eliminating the deleterious effects of parasitic noise that may be present on the signal, and a relatively good square wave signal on U3. Appears in the output. This allows a constant positive voltage at C3 to be applied to the inverting terminal of the square wave generator U4. Since U4 does not change, the output of the operational amplifier U6 is set to a low control level, and the positive rectangular wave signal appearing at the output of the operational amplifier U3 is transmitted to the base of the triode BG1 via the resistor R17. Then Triode B
G1 becomes conductive and generates a downward rectangular wave signal at its output, which is amplified by the amplifier to activate the relay,
When the control signal is high level, switch the headlight to low brightness,
The red and green lines are cut to connect the three lines of red, brown and yellow.

When the vehicle is overtaking or turning, the headlight must flash to notify the vehicle approaching to the front by a signal. It is operational amplifier U4, U
It suffices to activate 5, 5 and cooperate in parallel with the original manual dimming switch in the vehicle. In automatic low light mode, manual switching from high light to low light shuts off the power supply circuit to the thick film controller, C3 is discharged through diode D2, C4 is R24 and R26.
To discharge through. When the manual switch is reset to the strong light position, the power supply is restored to the thick film controller to generate a rectangular wave signal in U3, which is transmitted to the voltage amplifier U6 for comparison after Schmidt waveform shaping by the operational amplifier U5. It When the triode DG1 receives a regular rectangular wave signal output from the output 14 of the operational amplifier U6 at its base, the triode DG1 becomes conductive and generates a downward rectangular wave pulse at its output CT, and this pulse is transmitted to the relay section to contact the relay. To switch the HI and HO to LI and LO to switch the headlight Q.
The automatic switching is performed by forming multiple automatic switching between the strong light and the weak light to generate a hint signal to the headlight.

Four capacitors C3, C4, C5 and
C8 and two debugging resistors R1 ^*And R2^*Excluding
The remaining parts are integrated in the controller's integrated block.
The size of the pin is not larger than 30mm x 20mm, and the pin
Is as shown in FIG.

[0011]

As described above, in the automatic dimming control device in which the headlight is set to a low light when the vehicle approaches to improve the driving safety,
It has a manual dimmer so that when a vehicle turns or overtakes another vehicle, the light can be manually flashed on the other vehicle.

[Brief description of drawings]

FIG. 1 is a circuit diagram according to the present invention.

FIG. 2 is a schematic diagram of an integrated thick film circuit.

[Explanation of symbols]

 D ... Diode BG ... Triode C ... Capacitor R ... Resistor U ... Operational amplifier PV ... Power line CT ... Signal line K ... Dimmer switch HI, HO ... Signal line for strong light LI, LO ... Signal line for weak light Q ... Headlight light

Claims (2)

[Claims] 1. A control circuit for an automatic dimming controller in a vehicle, the control circuit comprising a signal input circuit, a non-inverting amplifier circuit, an inverting amplifier circuit, a low-pass filter, a voltage dividing circuit, a Schmitt circuit, and a rectangular wave. A generator D, a voltage comparator and an output circuit are provided, a diode D7, a capacitor C8 and a resistor R3 constitute the input circuit, operational amplifiers U1, R1 and R4 constitute the non-inverting amplifier, and R5, R6 and R7. , R2 and operational amplifier U2 constitute the inverting amplifier circuit, and R1
0, R12 and C5 form said low pass filter, R
8, R9, R13 and R25 constitute the voltage dividing circuit, R11 and R14 and the operational amplifier U3 constitute a Schmitt circuit, and C3, D2, R18, R19 and R20.
And an operational amplifier U4 constitutes the rectangular wave generator, and C
7, R21, R22, R23, C4, R24 and the operational amplifier U5 form a second-stage Schmitt circuit, and R25,
R26 and U6 constitute a voltage comparator, and triodes BG1, R27 and D4 constitute an output circuit connected to a signal contact of a relay, and a dimmer control circuit for a vehicle headlight. 2. Four capacitors, C3, C4, C5 and C8 and two debacking resistors R1 and R2.
All other elements are integrated into the IC block except
The overall size does not exceed 30 mm × 20 mm U ₁ (5),
U1 (6), U2 (10), U2 (8), U1 (4),
D1 (5), U5 (6), U5 (10), D4 (+1)
2. The dimmer control circuit for a vehicle headlight according to claim 1, wherein the dimmer control circuit is constituted by first to tenth ten pins for the ground and the ground.