An Efficient Switching Transient Analytical Model for P-GaN Gate HEMTs With Dynamic CG(VDS, VGS)

Accurate gate capacitance model is essentially important for switching transient analytical modeling of gallium nitride (GaN) high-electron-mobility transistor. In this article, by analyzing the charging of p-GaN/AlGaN/GaN gate structure, a dynamic gate capacitance C_G(V_DS, V_GS) model considering its dependence on both V_DS and V_GS is proposed, which has been validated by C_G measurement results with varying V_DS and V_GS. It has been identified in this article that the conventional static C_G model without considering its dependence on V_GS during switching could result in a lower C_G and underestimated Miller effect, resulting in discrepancy from the measured switching transient. By comparison, the implementation of the dynamic C_G(V_DS, V_GS) characteristics in the switching analytical model yields improved accuracy, by considering the two-dimensional electron gas accumulation and its impact on dynamic C_GD and Miller effect during switching transient. The switching transient analysis and dynamic gate capacitance C_G(V_DS, V_GS) characteristics are valuable for future high-frequency GaN-based power converter design.