The Power Vdmosfet Body Diode Of The Optimization Study

The evolution of faster and more powerful processors is driving ICs to lower operating voltages and higher current requirements. This demand for higher power/current densities puts even greater emphasis on the need to improve the efficiency of the power supply. To meet this challenge, many designers are considering synchronous rectifiers. The high density power MOSFET designs have been incorporated into DCDC buck converter. For Synchronous buck converter used in DCDC applications, one major contributor to switching losses is reverse recovery, sometimes is greater than the on-resistance. The low side MOSFET used in synchronous buck converters must be optimized to attain higher power efficiency. The purpose of this paper is to introduce three methods to reduce power loss of the low side MOSFET used in synchronous buck converters. First we only optimize device parameters without adjust device structure. And reverse recovery charge is reduced 30%. Second we present a novel VDMOS structure with an integral transistor to parallel body-diode. And reverse recovery charge is reduced at least 36.7%. . Third we present a novel VDMOS structure with an integral schottky diode to parallel body-diode. And reverse recovery charge is reduced 40.8%.