A voltage regulator module system with variable frequency modulation

A novel variable frequency modulation technique and apparatus for multiphase synchronous rectified voltage regulator module (Voltage Regulator Module, VRM) is proposed in this application. The proposed technique provides zero voltage switching (Zero Voltage Switching, ZVS) for high-side and low-side power switches under both light and heavy load conditions and thereby increasing the efficiency as compared to conventional approach. The dependency of switching frequency on the load condition for the proposed modulation technique and the related conduction loss are analyzed. It will be shown that the frequency increases under light load condition in order to retain ZVS and decrease the conduction loss. Although the switching loss will slightly increase due to the increase of switching frequency, the analysis and experimental results will shown the contribution of frequency increasing can cover this additional loss. Experimental results derived from a single-phase and an eight-phase synchronous rectified VRM show