Derivation of network functions for PWM DC-DC Buck converter in DCM including effects of parasitic components on diode duty-cycle

The paper considers an open loop-operation of a PWM DC-DC Buck converter at a constant duty-cycle. Under these conditions, the converters compensate the effects of the parasitic resistances adjusting the diode duty-cycle D1. All four network functions describing the frequency-domain behavior of a discontinuous conduction mode (DCM) operated DC-DC buck converter power stage are derived considering D1 adjustments. These network functions are derived in a closed form both manually and by using a symbolic circuit simulator. Bode plots of the network functions are also given for the buck converter. These functions are derived by utilizing a small signal equivalent circuit of the switching-cell composed of controlled current sources and resistances. Experimental results confirm the accuracy of theoretical derivations.