Abstract

Gallium Nitride High Electron Mobility Transistors (GaN HEMT) are widely used in high-frequency applications owing to their fast-switching speed and low switching loss. However, the large dVDS/dt transients can cause severe crosstalk, current overshoot, and EMI issues. While conventional gate drivers can mitigate these issues by slowing down the switching process, the switching loss is significantly increased. To reduce the switching loss under dVDS/dt limitation, this paper proposes a gate-side feedback active gate driver (AGD) to adaptively regulate the switching transient by providing three-stage driving currents. Switching points of the three-stage driving currents are determined by detecting the start of the Miller plateau through gate voltage slope and identifying its termination when the gate voltage exceeds the Miller plateau voltage. With the detected signal, the gate driving current during the Miller plateau is reduced to suppress dVDS/dt and mitigate current overshoot. Under 400 V/20 A conditions, experimental results show that the proposed driver can effectively control dVDS/dt and suppress current overshoot, while reducing the dVDS/dt-related switching interval by 68.13% and switching loss by 51.8%, thereby confirming its effectiveness.

IPC Classification

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