Abstract: In this paper,taking a 150 kHz switching-mode regulator with MOS power FETs as an example,a mathematical analysis is conducted by use of a state-space average method.And a general dynamic design method for the high frequency switching-mode regulator is developed.First,the state-space average method is used to derive a small signal average model of the power stage.Then the transfer functions of system can be derived.Finally,the computer aided method is used to analyze the dynamic performance and select the parameters of the circuit.