基于可变电感的谐振式多路均流LED驱动器

摘要

In order to solve the problems of the traditional LED driver adopting the frequency control with high EMI,pulse width modulation (PWM)with the complex control circuit,and the LLCC,LCLC resonant topology realizing constant current output system with the large volume,high cost and low power density,a resonant multi-channel sharing current LED driver based on variable inductor is presented.The variable inductor(VI)is used to replace the fixed inductance,which changes the resonant frequency for achieving dimming and controlling.Meanwhile,the resonant is introduced to realize the high conversion efficiency in ZVS(zero voltage switching)of all devices.The current sharing capacitor is used in each channel to simplify the structure of the circuit.Based on the theoretical analysis and simulation,an 11 W laboratory prototype is built to achieve the 4-channel LED driver.The research results show the multiple LED driver improves the characteristic of the current-sharing and frequency conversion dimming,as well as the power density and the service life of LED drivers,suiting for application in sur-gery dimming and home lighting.%为了解决现有LED驱动器采用变频控制实现后级的调光EMI高、脉宽调制(PWM)控制电路结构复杂,引入LLCC,LCLC等高阶谐振拓扑实现恒流输出系统体积大,成本高且功率密度低等问题,提出了一种基于可变电感的谐振式多路均流LED驱动器.采用可变电感(VI)代替固定电感值的方法,改变谐振频率实现调光及后级控制;引入谐振实现各开关管零电压开关(zero voltage switching,ZVS);将谐振电容用于各路均流以简化驱动器系统结构.根据LED驱动电路理论分析和仿真,设计制作了11 W实验样机,实现了4路LED均流调光.研究结果表明多路LED驱动电路改善了驱动器的均流和变频调光性能,提高了驱动器的功率密度和使用寿命,适合在手术照明和家庭照明中应用.