A Study on Novel Active Clamp Snubber Applied DC-DC Quasi Resonant Flyback Converter to Effectively Reduce Switch Voltage Surge

In this paper, active clamp snubber method was proposed to reduce effectively the switching surge voltage of the conventional quasi resonant (QR) flyback converter. The usefulness and practicality of the proposed method in QR flyback converter were verified through steady-state analysis and its experimental results. The performance of the proposed circuit was compared with the RCD snubber method. It was verified from the experimental results that the switch peak voltage of the proposed method was limited below 5% while the switch peak voltage of the RCD snubber was continuously increasing accordingly with the load current. Furthermore, this new active clamp snubber method could be applied to QR flyback and its power conversion efficiency was superior to the RCD snubber one.