Mathematic Modeling and Loss Analysis of Power MOSFET Based on Parasitic Parameters

In order to accurately describe the switching characteristic of power metal oxide semiconductor field effect transistor (MOSFET), a model based on parasitic parameters (Miller capacitance and parasitic inductance) was proposed in this paper. The mathematical expressions of both Miller capacitance and transfer characteristic were established by means of fitting method, respectively, and the mathematical expressions on voltage and current were also derived in detail. Moreover, the analysis on equivalent physical circuit was made for the voltage and current oscillation after being turned off. The more precise both voltage and current mathematical expressions are, the more accurate the reflection on loss of power MOSFET is. The simulation results verify the effectiveness of the proposed mathematical analysis model and equivalent physical circuit.