Self-Sustained Turn-OFF Oscillation of Cascode GaN HEMTs: Occurrence Mechanism, Instability Analysis, and Oscillation Suppression

This article presents a comprehensive study on the occurrence mechanism, instability analysis, and suppression methods of self-sustained turn- off oscillation, which occurs cascode gallium nitride high electron mobility transistors (cascode GaN HEMTs). In beginning, oscillation waveforms are analyzed, indicate that is determined by test circuit instability. Based double pulse test, impact load current $I_L$ , dc bus voltage notation="LaTeX">$V_{\text{DC}}$ gate resistance notation="LaTeX">$R_{G}$ identified. To investigate resonant circuit, small-signal ac model derived. model, influences various parameters analyzed. The analyses reveal possible can suppress oscillation. effectiveness proposed validated experimental data simulation results in end.