Efficiency is an important specification in power electronics converters. Low efficiency leads to meaningless heat loss and heat dissipation overdesign. The maximal  efficiency of the buck converter is usually about 98%, but it still has potential to further increases the efficiency. The main purpose of this paper is to design a buck converter with an efficiency higher than 99%. To realize such a goal, the cause of loss in buck converter is analyzed qualitatively first, and then quantitative calculation and device material selection are carried out for a specific working condition. Finally, a prototype is built according to the design results, and the efficiency of the Buck converter is higher than 99%.

Buck converter, efficiency, inductance loss, Capacitance loss