indicates the charge that must be supplied by the gate driver between the time that the threshold voltage has been reached and the time the drain current rises to Idmax at which time the drain voltage begins to change. Minimizing Qgs2 is a critical factor in reducing switching losses in Q1.
Qoss is the charge that must be supplied to the output capacitance of the MOSFET during every switching cycle. Figure A shows how Qoss is formed by the parallel combination of the voltage dependant (nonlinea.