Efficiency improvement of switched-mode power converters under light-load conditions

Modern power supplies must comply with strict regulations regarding efficiency and stand-by mode consumption. Thus, efficiency optimization in the whole operating range is mandatory and becomes a major design challenge, being specially difficult when both heavy and light load conditions must be addressed. This paper proposes an improved gate drive circuit to adapt the gate voltage to the load conditions. Thus, an optimum tradeoff between conduction and gating losses can be found, optimizing the power converter efficiency in the entire operating range. An efficient and cost effective implementation is proposed and tested, proving the feasibility of the proposed approach.