Analysis of winding capacitance effects on ringing choke converters

Effects of parasitic winding capacitance on the circuit operations of ringing choke converters are analyzed in this paper. Intrinsically, the ringing choke converter is a blocking oscillator but its flyback magneto-motive force is rectified for dc output. By adding a transition capacitor to increase the winding capacitance, the stabilization of output voltage is improved, and the required dummy load can be decreased. This article analyzes the switching pattern of ringing choke converters by qualitative state-plane analysis and verifies the parasitic capacitance effects at a 35-Watt circuit.