Design and Fabrication of Switching Characterization Set-up for GaN FETs

Wide band gap devices offer significant advantages such as high power density, fast switching and high efficiency. It is important to understand the trade-off involved in switching loss, conduction loss and reverse conduction characteristics for power converter design. Switching characterisation is essential for understanding the behaviour of new enhancement mode Gallium Nitride (GaN) power transistors that are available today. A theoretical method of switching loss estimation is presented in this work along with the development of a double pulse tester (DPT)-board for switching measurements. Careful layout design and measurement methodology is necessary for low measurement noise due to circuit parasitics. The designed DPT board has additional features for synchronous operation, short circuit test and variable temperature measurements. Additionally, the design of an air-core toroidal cage coil inductor is discussed, which ensures non saturated inductive switching of the device, even at high pulsed currents.