A multi-channel constant current lighting circuit for automobiles

A lighting circuit and automotive technology, applied in the field of electricity, can solve problems such as changes in LED lighting brightness, achieve lighting stability, overcome temperature drift, and facilitate adjustments

Active Publication Date: 2016-06-29
YANFENG VISTEON AUTOMOTIVE ELECTRONICS +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a multi-channel constant current lighting circuit for automobiles, the multi-channel constant current lighting circuit for automobiles should solve the problem that the brightness of automobile LED lighting changes with the battery voltage in the prior art technical problem

Method used

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  • A multi-channel constant current lighting circuit for automobiles

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Embodiment 1

[0013] like figure 1 As shown, a multi-channel constant current lighting circuit for automobiles of the present invention includes a pulse width modulation signal output terminal of a microcontroller MCU, a positive pole of a battery BATTERY, a ground terminal, an error detection circuit, and a negative feedback circuit , a first branch lighting circuit, a second branch lighting circuit, a third branch lighting circuit and a fourth branch lighting circuit, wherein the error detection circuit includes a first triode Q1 and a A second transistor Q2, the negative feedback circuit includes a third transistor Q3, a first resistor R1, a second resistor R2, a third resistor R3, a first diode D1 and a ninth resistor R9, the models of the first transistor Q1 and the second transistor Q2 are the same, the first transistor Q1 and the second transistor Q2 form a differential pair, and the first transistor Q1 The base is connected to the output end of the pulse width modulation signal, th...

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Abstract

A multi-channel constant-current lighting circuit for automobiles comprises an error detecting circuit, a negative feedback circuit and a plurality of branch lighting circuits, wherein the error detecting circuit comprises a differential pair comprising two homotype triodes; the negative feedback circuit comprises a triode, a resistor and a diode; each branch lighting circuit comprises a proportional current source circuit respectively; and each proportional current source circuit comprises a branch resistor, a branch triode and a branch LED respectively. The differential pair comprising the two triodes can solve the problems caused by temperature shifting and instable supply voltage by detecting error current numbers of a power supply and cooperating with the negative feedback circuit, so that the lighting is more stable and the lighting circuits are independent of one another; the current of the LEDs can be adjusted conveniently, and multi-channel output capability can be expanded conveniently; and the current can be adjusted through PWM (Pulse-Width Modulation) signals with different duty ratios output by a micro-controller, thereby realizing software dimming without changing the circuits.

Description

technical field [0001] The invention relates to the electrical field, in particular to a lighting circuit, in particular to a multi-channel constant current lighting circuit for automobiles. Background technique [0002] Electronic components in cars such as radios, air conditioning control heads, and instrument clusters are illuminated by LEDs. The customer requires that the brightness of the LED lighting should have a stable performance under different temperatures and different car battery voltages (usually between 9v~16v). In the prior art, the commonly used LED lighting circuits are as follows: ① LED and current-limiting resistor are connected in series, and then connected to the positive terminal and negative terminal of the power supply. This circuit is the simplest, but the current of the LED changes with the battery voltage, resulting in a significant change in brightness. ② Add a switching transistor on the basis of ①, and the MCU (microcontroller) in the car ECU...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05B37/02B60Q1/00
Inventor 王辉
Owner YANFENG VISTEON AUTOMOTIVE ELECTRONICS
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