谐振式单开关多路低纹波输出LED驱动器

Resonant Single-Switch Multi-Channel Low-Ripple LED Driver

该文提出一种谐振式单开关多路低纹波输出LED驱动器。所提出的LED驱动器由前级Buck-Boost功率因数校正(PFC)变换器与后级谐振式多路均流输出DC-DC变换器通过一个有源开关整合而成,简化了拓扑结构和控制回路。该LED驱动器利用谐振电容的电荷平衡实现多路输出的均流控制,因此只需控制其中一条输出支路的电流,其他输出支路可实现自动均流。利用宽带宽电压模式控制环路,消除了Buck-Boost PFC变换器输出电压纹波对各输出支路的影响,即实现了多路低电流纹波输出。最后搭建了一台82W的三路恒流输出实验样机,验证了理论分析的正确性。

This paper presents a resonant single-switch multi-channel low-ripple LED driver.The proposed LED driver is integrated with a front-end Buck-Boost power factor correction(PFC)converter and a back-end resonant multi-channel current-sharing output DC-DC converter through an active switch,which simplifies the topology and control loop.The proposed LED driver realizes the current sharing control of the multi-output using the charge balance of the resonant capacitor.Therefore,only the current of one output branch is controlled,the current of other output branches can be automatically balanced.Through the wide-bandwidth voltage mode control loop,the effect of the output voltage ripple of the Buck-Boost PFC converter on each output branch is eliminated,i.e.,low output current ripple of the multiple LED strings can be realized.Finally,an 82W three-string LED driver prototype was built to verify the theoretical analysis.