A novel regenerative snubber circuit for flyback topology converters

Switch mode power suppliers based on isolated flyback topology have voltage stresses on semiconductor switches caused by transformer leakage inductance. Those voltage stresses have to be mitigated by implementing active or passive clamp preferably with partial leakage energy recovery. In this paper a new integrated semi-active regenerative (lossless) snubber is proposed. The proposed snubber topology is featured by the snubber inductor integrated into the main transformer thus decreasing component count and saving the PCB space. Partial coupling of snubber inductor with a secondary side makes it possible to recover part of the transformer leakage energy directly to the secondary side with potential to increase snubber efficiency. The operation of the proposed snubber is analyzed and simulation results are presented. Interesting is that with the proposed snubber various side effects can be reached like reduction of RMS current in secondary side, ZCS and ZVS modes for secondary side rectifier and primary main switch along with achieved primary goal – voltage stress limitation and transformer leakage energy recovery.