Abstract：Two-stage circuit is widely used in the high-power LED driver supply. However, the cost increases for requiring more components and two sets of control, and the full-bridge diode rectifier also reduces the converter efficiency due to the large conduction losses. This paper presents a novel single-stage (SS) bridgeless Boost-Buck circuit. Boost circuit serves as a PFC stage and Buck as a DC/DC stage. Bridgeless structure can reduce conduction losses effectively, the proposed DCM+CCM control strategy is used to simplify the control. At last, a prototype with 85~135Vrms input and 2A/150W output was set up to verify the theoretical analysis．The power efficiency>90%, high power factor≥0.985 and THD<17% were achieved at rated output power. The experimental results show that the proposed topology has better performance than two-stage Boost+Buck in low-input voltage & high-input current occasion.
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2015, Vol. 16 
