A merged dual-gate power MOSFET is described which greatly improves the light-load energy efficiency of high-speed (PIMHz) low-voltage DC/DC conversion by dynamically reducing input capacitance and gate drive losses during lowcurrent load conditions. The W-switched MOSFET concept is experimentally verified using a TrenchFET employing a 30X reduction in input capacitance during light load. Efficiency improvements better than 25% and a decade increase in useable load current were confirmed for a 1-cell LiIon to 5-V boost converter, without adversely affecting the converter's transient response. Various figure-of-merits for W-switched MOSFETs are also proposed to analyze the limits of W-switching.

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