一种单级无电解电容LED驱动电路

A Single-Stage Electrolytic-Capacitor-Free LED Driving Circuit

基于Flyback的单级LED驱动电路的隔离变压器漏电感严重影响了驱动电路的工作效率,同时由于电解电容的存在,缩短了LED驱动电路的寿命。研究了一种带漏电感能量回馈通路的Buck-Boost＋Flyback单级PFC驱动电路,利用一个二极管作为变压器漏电感能量回馈通路,消除开关管上的电压尖峰。建立了一定输出功率条件下中间级电容两端上限电压与电容值之间的函数关系,根据关系曲线选取合理的瓷片电容取代电解电容。研制一台输入130～260 V,输出为33 V/150 mA的实验样机验证了理论的正确性。

Due to the isolation transformer leakage inductance, the efficiency of single-stage LED driver circuit based on Flyback was seriously affacted, and electrolytic capacitors shorten the life of the LED driver circuit. This paper studied on a Buck-Boost ＋ Flyback single-stage PFC drive circuit which exploited a diode path to recover the leakage inductance energy and alleviated the voltage spike on switch. The function of extreme capacitor voltage and the capacitance with a certain output power was established. According to the function curve, the reasonable ceramics could be selected to replace electrolytic capacitor. An input 130--260 V, output 33 V/150 mA experimental prototype was established and debugged, the correctness of theoretical analysis is validated by experiments.