Design and implementation of a LED driver with current balancing

In this paper, the design and implementation of a LED driver with current balancing are presented. The proposed driver includes a boost power factor correction converter as front-stage and a half-bridge resonant inverter as rear-stage. With the current balancing scheme, the driver is suitable to drive the multi-string LEDs. The effect of the LED equivalent model on the resonant circuit and the driver operating principles are discussed. The design and characteristics of proposed current balancing scheme are also considered. Finally, a two-stage LED driver with current balancing is implemented to drive 4 strings LED module, which contains 15 pieces 1 W white light LEDs for each string. Experimental results show that the proposed circuit can be operated at 90∼264 Vrms AC input voltage range and the highest efficiency is 87.9 %.