Control circuit for LED car lamp

Abstract

The invention relates to a LED car lamp control circuit comprising a LED car lamp assembly which includes several LEDs, at least one reflecting unit and at least one heat elimination unit; a driving circuit for controlling the LED to keep a stable brightness, chrominance and color temperature by controlling the input magnitude of the LED driving current; and a temperature sensing circuit for sensing the temperature of a certain measuring point of the LED car lamp assembly, and triggers the driving circuit to execute the action of output driving current magnitude correction by electronic signal as soon as the temperature reaches a preset value. Consequently, the invention can realize the even brightness, stable temperature of the LED, thereby avoids the damage to the LED caused by extra high temperature and avoids the changed brightness, chrominance and color temperature of the LED out of the criterion of relative car lamp controlling laws, consequently, can prolongs the service life of the LED.

Description

technical field [0001] The invention relates to a control circuit for LED car lights, especially a design for adjusting the driving current of the LED by sensing the change of the temperature or forward voltage of the LED, thereby making the brightness output value of the LED stable. Background technique [0002] Press, the current technology for LED (Light Emitting Diode) technology has made its brightness comparable to that of ordinary light bulbs, and there are also products with lighting functions that use high-brightness LEDs as the luminous body of the product, for example LED lights. When the LED is used as the illuminant of the car light set, the car light set must still meet the requirements of the relevant regulations on car lights, such as standard specifications such as the brightness of the car light and the chromaticity or color temperature of the light. The so-called chromaticity is a standard defined by the International Commission on Illumination (CIE), whi...

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Problems solved by technology

[0003] However, the aforementioned LEDs have defects such as changes in brightness and light chromaticity or color temperature as the temperature changes.

In other words, the LED has the characteristic of temperature coefficient of forward voltage (Temperature Coefficient of Forward Voltage), that is, when the lamp equipped with LED is started and used for a period of time, the LED will generate a certain The heat causes the temperature of the LED body to rise, and the forward voltage of the LED will drop at this time, and the temperature rise will cause the internal quantum efficiency of the LED to decrease, which will weaken the brightness of the LED and the color If the brightness or color temperature of the vehicle light changes, so that the brightness and chromaticity or color temperature of the said vehicle light do not meet the requirements of the regulations on the control of vehicle lights

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