A family of asymmetrical dual switch forward DC-DC converters

Dual-switch forward converter is the preferable candidate in occasion of medium-low power range application under high-line input due to lower voltage stress of switches for the very topology. However duty cycle of the conventional dual-switch topology is less than 50%, which influences its adaptability of wide-range input application. In order to supply appropriate topology for application of medium-low power range under high-line input, asymmetrical dual-switch forward topology is presented in this paper. The presented topology features both lower voltage stress of switches and good adaptability of wide range input. Three types of asymmetrical dual-switch forward topologies are proposed in this paper: RCD reset asymmetrical dual-switch forward converter; resonant reset asymmetrical dual-switch forward converter; active-clamped asymmetrical dual-switch forward converter. Characteristic of these topologies is analyzed in detail and comparison between every two of them is done. Finally, the above characteristic is verified by the experimental result.