H-Bridge Derived Topology for Dynamic On-Resistance Evaluation in Power GaN HEMTs

Gallium nitride high electron mobility transistors outperform Silicon devices due to their excellent physical properties. However, being an immature technology, it exhibits dynamic on-state resistance (Rds,on). This causes increased conduction loss and leads to reduced operating efficiency. To evaluate the dynamic Rds,on of the device, a measurement circuit is required. In literature, a standardized double pulse test is widely used for the measurement of Rds,on. However, due to the uncontrolled off-state time and inability to independently adjust, the test conditions result in restricted measurement. This article proposes a measurement circuit of the device in power electronics operations. The circuit uses an H-Bridge-derived topology with capacitive storage to enable forward and reverse conduction mode measurement of the device. In all the modes, the circuit allows measurement from the first switching cycle and independent control over the testing conditions by using a hysteresis current control. The proposed measurement circuit is validated using simulation and experimentation. Finally, analytical efficiency compared with the state-of-the-art measurement circuits is provided.