New Control Strategy for Synchronous Rectifier to Maximize Efficiency of Full-Bridge Converter with Asymmetric PWM Method

This paper proposed a novel driving method for synchronous rectifier (SR) of the asymmetric pulse-width-modulation (APWM) controlled full-bridge (FB) converter. To maximize the efficiency of converter, the current flows through the channel of SR switches rather than through the body-diode of SR switches. In addition, the reverse recovery current by operation of body-diode in SR switches are dramatically reduced. The switching losses from SR are minimized by considering transients of SR switch operation. The proposed SR driving method is applied in both discontinuous (DCM) and continuous (CCM) current mode. Then, the operations of converter with proposed SR driving method are mathematically analyzed. The performances of converter are evaluated by experimental results from an implemented converter prototype with 800 W.