The efficient deployment of silicon super-junction MOSFETs as synchronous rectifiers

Charge-compensated or "Super-junction" MOSFETs exhibit low on-state resistances and low switching losses. However, the reverse recovery behaviour of their intrinsic diodes and their output capacitance characteristics make their deployment as synchronous rectifiers challenging. A simple auxiliary circuit is proposed to address these issues, by reversing the direction of current flow in the MOSFET channel at turn-off, thereby deactivating the intrinsic antiparallel diode and partially charging the MOSFET output capacitance. The proposed technique is verified on a 400 V, 1 kW buck converter.