Unified large signal modeling method for DC-DC converters in DCM

A simple and general large signal model for DC-DC converters in discontinuous conduction mode (DCM) is proposed in this paper. The proposed large signal model has the following advantages: 1) unified and general, 2) simple and convenient to be derived, 3) both the steady-state model and small signal model can be obtained easily. Large signal averaged circuit model is built, and small signal model can be derived from it. In this model, the active switch is modeled by a current source, the diode is modeled by a voltage source and the inductor is modeled by a current source. The proposed modeling method is also convenient to be applied to various DC-DC topologies. The Pspice simulation was used to verify the proposed model. A 12 V input and 1.5 V output buck converter was built to verify the analytical analysis.