A Resonant Converter with PWM Control

A dc-to-dc converter of resonant type regulated by PWM means is presented. The converter consists of two stages. The first stage is the boost converter with a switch of MOS FET. The change of the output voltage is regulated by this switch. The second stage is the self-oscillating inverter with rectified output. In the dc side of the output rectifier, a parallel capacitor is connected. A resonant condition is satisfied between the capacitor and the leakage inductance of the inverter transformer. The resonant frequency is almost the same as that of the oscillating frequency. With the resonance phenomena, the switching loss of the transistor is decreased. A good regulation is obtained by the feedback from the output to the boost converter.