Factors Affecting Self-Sustained Switching Oscillations of Cascode GaN Devices and Mitigation Strategy during Parameter Design

With the fast development of wide band-gap devices, GaN is occupying a larger market than before. As one of the commercial devices, cascode GaN has shown several advantages. However, its cascode configuration brings oscillation problems. Although some related research has been done, comprehensive experimental tests to analyze the factors affecting self-sustained oscillations have not been conducted so far. In this paper, it is the first time that the effects of gate resistors, gate driving voltages, and snubbers on self-sustained oscillations during both turn-on and turn-off transients are comprehensively and experimentally studied. It is shown that decreasing gate resistors, increasing positive driving voltage, decreasing negative driving voltage, and adding snubber circuits can suppress the self-sustained switching oscillations.