Application of the Grey-Box Modelling to Simulate GaN HEMTs

A method for obtaining an equivalent circuit of a GaN high electron mobility transistor based on the network analysis over a wide range of operating points is described. The resulting model can predict the device’s RF behaviour, in a frequency range adjustable by the equivalent circuit’s configuration, and can be likewise made to describe large-signal characteristics by augmenting it with the Chalmers-Angelov model [1], after additional I-V measurements. Moreover, the effects of charge-carrier trapping were considered that, most notably, change the transistor’s dynamic output resistance [2]. The possibility of evaluating charge-trapping parameters via the grey-box model is discussed. This approach can provide capabilities for more robust simulation of pulsed-power circuits where GaN HEMTs play a role of switching elements with low rise times and possibilities of the bi-directional functionality.