Experimental characterization of power VDMOS transistors in commutation and a derived model for computer-aided design

The authors present an experimental method for the characterization of MOS power switching transistors that does not involve technological parameters that are not available to designers. The method is based on the time-domain analysis of the commutation performance of the transistor when constant current are injected into its terminals. The analysis of the time-domain waveforms and the knowledge of the internal structure of the MOS devices are sufficient for the evaluation of the transistor capacitances. It is then possible to introduce a simple large-signal model for power MOSFETs that is particularly well suited to the analysis of circuits using the MOS transistor in commutation (e.g., switching power converters or high-efficiency power amplifiers). The authors also present the model implementation in the SPICE 2 program. Comparison between results obtained experimentally and by computer simulation for several circuits confirms the accuracy of the proposed method