Active Clamp Forward Converter with Light-load Efficiency Optimization Control Strategy

Abstract

This paper proposes a new control strategy applicable to active clamp forward converter (ACFC) under light load conditions. Conventional ACFC is difficult to achieve high efficiency under light load conditions due to conduction losses caused by the excessive freewheeling current. The proposed control strategy can significantly improve the light-load efficiency while reducing conduction losses without the need for additional circuitry. The feasibility and performance of the proposed control strategy are experimentally verified with a USB PD adapter prototype designed for a universal AC input and 65W maximum output.