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LED Constant Current Power Supply

Sep 26, 2019

LED Constant Current Power Supply

LED constant current power supply is used to supply power to LED lamps. Since the current flowing through the LEDs is automatically detected and controlled during power supply operation, there is no need to worry that excessive current flows through the LEDs at the moment of power-on, and there is no need to worry about short-circuiting of the load, breaking down the power supply.


Constant current driving mode can avoid the change of LED forward voltage and cause current fluctuation, while constant current makes the brightness of LED stable, and it is also convenient for LED lamp factory to ensure product consistency when mass production is implemented. Therefore, many manufacturers have already been fully aware of the importance of the driving power. Many LED luminaire manufacturers have abandoned the constant voltage mode, and used the slightly higher cost constant current mode to drive the LED luminaire.


Some manufacturers are worried that the choice of electrolytic capacitors on the power driver board will affect the life of the power supply. In fact, it is a misunderstanding. For example, if 105 degrees is used, the high temperature electrolytic capacitor with a life of 8000 hours will be reduced by 10 degrees according to the current life expectancy of electrolytic capacitors, and the driver life expectancy doubled, so it has a working life of 16,000 hours in a 95 degree environment, a working life of 32,000 hours in a 85 degree environment, and a working life of 64,000 hours in a 75 degree environment. If the actual operating temperature is lower, then the life will be longer! From this point of view, it has no effect on the life of the drive power as long as we choose electrolytic capacitors of high quality.


There is also one point worthy of attention for LED lighting companies: As the LED will release a lot of heat during the working process, the working temperature of the light will rise rapidly. The higher the LED power, the greater the heating effect. The increase of the temperature of the LED chip will lead to the performance of the light-emitting device. The change and the electro-optical conversion efficiency are attenuated, and even fail when the situation is serious. According to the experimental test, the luminous flux decreases by 3% for every 5 degrees Celsius increase of the LED's own temperature. Therefore, the LED lamp must pay attention to the heat dissipation of the LED light source itself. Try to increase the heat dissipation area of the LED light source as much as possible, and try to reduce the working temperature of the LED itself. If conditions permit, it is better to separate the power supply part from the light source part. It is not advisable to pursue the small volume blindly and ignore the operating temperature of the lamp and the power supply.