An experimental study on switching waveform design with gate charge control for power MOSFETs

Abstract

Designing switching waveforms is a technique for mitigating a trade-off between loss and noise in switching power devices. A novel and simple method has been proposed to compute the gate waveform to realize a designed switching waveform. The gate current pulse is calculated to eliminate the deviation between the designed target waveform and the observed waveform at the moment using a linear combination of drain-source voltage or drain current responses to a small gate charge pulse train. In this paper, a verification system including a simple gate current pulse generator consisting of operational amplifiers and transistors was built together with a conventional voltage source gate driver, and validation of the proposed method was experimentally performed using the drain-source voltage waveform of a Si MOSFET during the turn-off phase. Applying the obtained drain-source voltage responses to the proposed method, the gate current pulse to be added to realize a given target waveform was calculated and superimposed on the output of the gate driver. The measured drain-source voltage waveform was well-matched to the target. In addition, the impact of the drain current values on the design of the drain-source waveform was verified.