Zero-voltage-switching multi-resonant technique-a novel approach to improve performance of high frequency quasi-resonant converters

The power transistor in zero-current-switched quasiresonant converters (ZCS-QRCs) suffers from excessive voltage stress, and the converter regulation characteristics and stability are adversely affected by parasitic oscillations caused by the junction capacitance of the rectifying diode. A novel, multiresonant switch concept is proposed to overcome these problems. A unique multiresonant network arrangement results in absorption of all parasitic components, including transistor output capacitance, diode junction capacitance, and transformer leakage inductance, in the resonant circuit. This results in favorable switching conditions for all devices. Experimental results show that ZVS multiresonant converters are superior to ZVS-QRCs due to reduced transistor voltage stress and improved load range and stability.<>