De-skewing Algorithm for Accurate Switching Loss Calculation in GaN HEMT

A double pulse test (DPT) method is widely used for switching loss analysis. Considering the high switching capabilities of wide bandgap (WBG) devices such as Gallium Nitride (GaN) and Silicon Carbide (SiC), measurement results are susceptible to errors due to the variable propagation delays offered by different probes. The commercially available methods, such as calibration fixtures, prove inadequate for de-skewing at high voltage and current ranges. Alternatively, the de-skewing process often necessitates circuit modifications, such as replacing the load inductor with a resistor, introducing complexities that compromise the accuracy of the obtained result. This article aims to develop an algorithm for de-skewing the measured data to determine the switching loss of the device accurately and quickly. The algorithm also estimates the effective parasitic inductance of the switching path. To validate the proposed algorithm, a DPT setup is developed using GaN HEMT devices of 650 V/30 A.