Wavelet based MOSFET switching loss analysis

Switching loss calculation in MOSFET requires device parameters like turn-on and turn-off time, input and output capacitances, parasitic inductances and circuit parameters like voltage, current and operating frequency. Using these parameters switching loss is calculated with given approximate mathematical formulae. This paper presents a wavelet based method for switching loss calculation. It requires only the voltage and current waveforms during switching and calculates the power loss and also provides the frequency content during switching. The information regarding frequency content can be utilized for designing snubber as well as for EMI analysis. Multi Resolution Analysis (MRA) is used to decompose signals in wavelet domain and the signals are transformed in different frequency bands. The power is calculated in each band by multiplication of current and voltage wavelet coefficients. Simulation results are presented for a MOSFET with inductive load to support the method described.