A high efficiency bridgeless flyback PFC converter for adapter application

This paper proposes a high efficiency low cost AC/DC converter for adapter application. In order to achieve high efficiency and low cost for adapter with universal AC input, a single stage bridgeless flyback PFC converter with peak current clamping technique was proposed. Compared with conventional flyback PFC converter, the conduction loss is reduced due to bridgeless structure. And the size of transformer can also be significantly reduced due to lower peak current, which results in lower cost and higher power density. Detailed operation principles and design considerations are illustrated. Experimental results from a 90W prototype with universal input and 20V/4.5A output are presented to verify the operation and performance of the proposed converter. The minimum efficiency at full load is above 91% over the entire input range.