A mathematical model for power MOSFET capacitances

The capacitance-voltage equations are derived and then directly implemented into a power MOSFET model as an alternative to the sub-circuit approach. The goal is to develop a fast and simple power MOSFET model whose parameters depend on easily measured external device properties rather than internal phenomena. By deriving equations directly from device physics one obtains accurate functioning over a wide range of circuit conditions and device types. The capacitance-voltage characteristics of the interelectrode capacitances in the power MOSFET are mathematically described. The internal charge conditions which determine the capacitances for different operating states are presented. Experimental three-terminal capacitance data are compared with simulated results, followed by a brief description of how the parameters were determined