Analysis and Implementation of an Active Clamp ZVS Forward Converter

Abstract

The system analysis and circuit implementation of ZVS forward converter with center-tapped rectifier are presented in this paper. To reduce the voltage stress of active switch in the forward converter, one auxiliary switch and one clamp capacitor are used in the adopted converter to recycle the energy stored in the transformer leakage. The resonant circuit based on the output capacitance of switches and leakage inductance of the transformer achieves zero voltage switching turn-on for both switches in the adopted converter to increase the total circuit efficiency. The center-tapped rectifier is used at the secondary side to achieve full-wave rectifier. In the high output current applications, the synchronous rectifier can be used in the secondary side to further reduce the conduction losses of rectifier diodes. The operation principles of the adopted ZVS forward converter with center-tapped rectifier are analyzed in detail. The design consideration and circuit example of ZVS forward converter are presented. Finally experimental results based on a ZVS forward converter with 5 V/16 A output load are provided to verify the effectiveness of the adopted converter