A novel energy recycling clamp circuit

The reverse recovery of the output rectifying diodes in converters often causes excessive power loss in semiconductor devices and voltage spikes across the diodes, resulting in lower efficiency. There are many kinds of snubber circuits used to clamp voltage spike across the diodes and recycle the reverse recovery energy, which have many limitations such as the bad effect for spike killing, not working in output short circuit. To overcome the limitations a novel snubber circuit is put forward in the paper, which is lossless and more effective than the prior ones. In addition, during the main circuit operates in the current limit mode, the snubber circuit operates normally. The principle and analysis of the snubber circuit are presented in the paper. In a 3 kW telecom power supply very good results are obtained by applying the circuit.