An Accurate Switching Current Measurement Based on Resistive Shunt Applied to Short Circuit GaN HEMT Characterization

The use of a resistive shunt is one of the simplest and most used methods for measuring current in an electronic device. Many researchers use this method to measure drain current during short-circuiting of fast devices such as GaN HEMTs. However, the high switching speed of these devices together with the non-ideality of the shunt resistors produces an overestimation of the current in the initial phases of the transient. In this paper, a passive compensation network is proposed, which is formed by adding an inductor to the voltage measurement circuit and allows an accurate measurement of the current using the resistive shunt even in the presence of very fast devices. The proposed method is validated by simulations and experimental measurements.