Using the averaged switch modeling approach,a non-linear large-signal averaged model of non-ideal PWM switch is derived,taking into account all parasitic resistances and threshold voltage of diode.

It establishes unified equations of such circuits by describing the switching components in the circuits as ideal switches in the circuits,then solved by the backward Euler method.

Low frequency small signal transfer function deduction algorithm is systematically presented for switching power converter using state space average method,and its average model is given based on PWM switch model.