Practical investigation of the gate bias effect on the reverse recovery behavior of the body diode in power MOSFETs

This work considers an alternative method of reducing the body diode reverse recovery by taking advantage of the MOSFET body effect, and applying a bias voltage to the gate before reverse recovery. A test method is presented, allowing the accurate measurement of voltage and current waveforms during reverse recovery at high di/dt. Different bias voltages and dead times are combined, giving a loss map which makes it possible to evaluate the practical efficacy of gate bias on reducing the MOSFET body diode reverse recovery, while comparing it to the well known methods of dead time optimization. A selection of 60V devices for synchronous rectification are compared for their suitability for gate bias, while a selection of 600V devices are compared for the efficacy of gate bias for the zero voltage transition converter application. The results show that many of the tested devices benefit from greatly reduced reverse recovery after the application of gate bias.