The Si9150 synchronous buck regulator controller is ideally suited for high-efficiency step down converters in battery-powered equipment. Combined with the Si9943DY MOSFET half-bridge, a 90% efficient, 7.5-W, 3.3-V or 5-V power supply can be implemented using standard surfacemount assembly techniques. The wide input range allows operation from NiCd or NiMH battery packs using six to ten cells.