An active-clamp snubber for isolated half-bridge DC-DC converters

In the conventional isolated half-bridge DC-DC converter, the leakage-inductance-related losses degrade the converter efficiency and limit the increase of the converter switching frequency. A novel active-clamp circuit is proposed to recycle the energy stored in the leakage inductance and thus improves the converter efficiency. By transferring the energy in the leakage inductance to a capacitor, the leakage inductance energy is recycled. Moreover, the proposed active-clamp circuit avoids the body diodes conduction of primary-side switches. Hence the body diodes conduction and reverse-recovery losses are eliminated. The principles of operation and simulation results are presented. The experimental results show the proposed active-clamp circuit improves the efficiency of the half-bridge DC-DC converter.