Linear constant current drive mode of LED signal lamp for automobile

Abstract

The invention relates to a linear constant current drive mode of an LED signal lamp for an automobile, which belongs to the field of electric illumination. The linear constant current drive mode comprises that a linear constant current control module is arranged between a direct current supply and the LED signal lamp for the automobile connected with the direct current supply and provides linear constant current drive for the LED signal lamp for the automobile, wherein the linear constant current control module comprises a voltage-stabilizing unit, a protective unit and an executing unit; and at the stage that the value of the working current of the LED signal lamp is lower than that of set current, the forward working current of an LED generates linear change following the change of input power supply voltage. After the working current of the LED reaches the set working current, the working current of the LED is set at a setting value by a constant current way; and after the value of the working current of the LED is larger than the setting value, the working current of the LED does not generate linear increase following the increase of the power supply voltage, and current outputted by a load is constant. The linear constant current drive mode has the advantages of simple current structure and low production cost, and is particularly suitable for the linear constant current drive of the LED signal lamp of a low current automobile. In addition, the linear constant current drive mode prevents heavy current from damaging the LED.

Description

technical field [0001] The invention belongs to the field of electric lighting, and in particular relates to a control method and a control device for LED lamps used in automobiles. Background technique [0002] In the mid-1980s, LEDs (Light Emitting Diodes, light-emitting diodes) began to be used in automobile central high-mounted stop lamps (CHMSL, Central High Mounted Stop Lamp). Panel backlighting generally adopts LED as a new solid-state light source. After entering the new century, with the improvement of LED power and brightness, in addition to automobile headlights, LED has fully entered the application of automobile lighting and signal systems. [0003] The biggest difference between automotive LED lamps and halogen lamps is that automotive LED lamps cannot be directly powered. Therefore, to use LEDs as lighting sources, it is necessary to solve the problem of power drive. [0004] At present, the driving circuits of automotive LED signal lights can be roughly divi...

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Problems solved by technology

[0015] But relatively speaking, the DC-DC conversion type is relatively expensive, requires a dedicated control chip and peripheral structures such as inductors and capacitors, and has high-frequency oscillation signals. From the perspective of electromagnetic compatibility, the DC-DC conversion type is prone to electrical noise. , will also generate strong electromagnetic interference to the surrounding electrical devices

[0016] Considering that in the field of LED drive control with low current, by properly arranging the connection of LED strings, the power consumption on the drop-down resistor itself is very small. If the DC-DC conversion drive circuit is used, it cannot take advantage of its high efficiency. , on the contrary, it will increase the manufacturing cost a lot, and there is also the possibility that the electrical noise will exceed the standard

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