Uniform Models of PWM DC–DC Converters for Discontinuous Conduction Mode Considering Parasitics

Abstract

Uniform steady-state and small-signal circuit models for pulsewidth-modulated dc-dc converters operated in discontinuous conduction mode are presented. The models are developed using a new approach that accurately accounts for nonlinearity of current waveform due to component parasitic resistances. The uniform model structure for a set of dc-dc converters is transformed by substituting the practical inductor with an equivalent inductor in series connection with the output capacitor. The resulting models are used to derive the uniform expressions of voltage transfer ratio, efficiency, and various transfer functions. The proposed models can be considered as an alternative to the previously established techniques, and are shown to be fairly accurate in steady-state and small-signal representations through detailed simulations and experimental tests.