A Novel Gate Driver Approach Using an Inductive Feed Forward for a Robust Turn-on of GaN Power Transistors with Gate Injection

Many GaN power transistors contain a PN junction between gate and the channel region close to the source. In order to maintain the on-state, current must continuously be supplied to the junction. Therefore, the commonly recommended approach uses a gate bias voltage of 12 V to compensate the Miller current through a boost circuit. For the same purpose, a novel gate driving method based on an inductive feed forward has been presented. With this, stable turn-on can be achieved even for a bias voltage of only 5 V. The effectiveness of this concept is demonstrated by double pulse measurements, switching currents up to 27 A and a voltage of 400 V. For both approaches a compact design with low source inductance is characterized. In addition to the significant reduction of the gate bias voltage and peak gate current, the new approach reduces the switching losses for load currents A.