Abstract: This paper introduces a forward zero voltage transition(ZVT) soft switching DC DC converter, and describes its principle and characteristics. Compared to the previous soft switching techniques,ZVT technique achieves zero voltage switching for both the active and passive switches without additional voltage and current stress. In the meantime, the soft switching operation can be easily maintained for wide line voltage range and load range, and the switching losses and noises can be reduced by applying the ZVT auxiliary resonant commutating network to the conventional converters. The circuit and its experimental results are given for 24V/9A DC DC converter using ZVT technique and integrated control block SG3525A.

Key words: zer o-voltage-tr ansition, converter, soft-switching