Mechanism analysis of different undamped oscillations for GaN devices

Gallium nitride high electron mobility transistors (GaN HEMTs) are widely used due to their advantages of fast switching speed and low on-resistance. However, these may lead to undamped oscillations. Current research primarily focuses on the mechanism analysis and modeling of single-mode undamped oscillation, without considering transition between different undamped oscillations. There is a lack of theoretical research on systems that satisfy mechanism of different undamped oscillations. This article analyses the transition mechanism of undamped oscillations in the turn-OFF process. First, the generation mechanism of different oscillation is analysed. Then, a high-frequency equivalent model is established to study the influence of various parasitic parameters on oscillations. Finally, the accuracy of proposed theory is verified by experiment. The theory and modelling in this article comprehensively analyse the generation and transition mechanism of undamped oscillations and provide a systematic theoretical basis for studying undamped oscillations.