Single-stage high-power-factor LED driver with ZVS and current-sharing features

摘要

This paper proposes a single-stage, high-power-factor LED driver with zero-voltage-switching (ZVS) and current-sharing features. A buck-boost typed power-factor corrector (PFC) is integrated with an LLC resonant dc-dc converter to form the presented circuit. Both the active switches can turn on with ZVS, and both the output rectifier diodes can turn off with zero-current-switching (ZCS). The current sharing of LED channels is achieved naturally by employing multiple transformers and connecting their primary windings in series. The proposed single-stage converter has the features of simple circuit structure, low dc-bus voltage, and high system reliability. Operation principles, and circuit analysis of the proposed converter are addressed. Finally, the experimental results of a laboratory prototype are provided to verify the validity of the theoretical predictions and the feasibility of the proposed circuit.