Zero cross switch at turn-off for PWM switching converter

The authors have developed a quasiresonant DC-to-DC converter that has lower switching losses than the conventional pulsewidth modulated converter and is more amenable to higher switching frequencies. They present a detailed discussion of the concepts of the quasiresonant DC-to-DC converter, including principles of operation in which the discharge of the input capacitor is controlled to enable zero-cross switching during on-to-off transitions of the switching devices based on the resonant combination of the input capacitor and the transformer leakage inductance. Analytical data are also presented