Comprehensive MOSFET Capacitance Characterization Based on Charge Trajectories

A novel method for determining the parasitic capacitance of power MOSFETs is proposed. Unlike conventional methods that rely on small-signal measurements under specific bias conditions, the proposed method leverages the instantaneous switching waveforms of a MOSFET to characterize its capacitance. The switching waveform inherently establishes appropriate bias voltages for all electrodes, reflecting real-world operating conditions. By analyzing charge transfer trajectories during switching, the gate-source, drain-gate, and drain-source capacitances are determined. Evaluations demonstrate that the capacitance models derived from the proposed method accurately reproduce the switching waveforms in a boost converter using a silicon carbide (SiC) MOSFET, leading to a ${4}\times $ reduction in switching timing errors compared to conventional models obtained through the small-signal measurements.