This paper presents the high efficiency receiver IC for wireless power transfer application. The active rectifier is designed to have the wide input dynamic range since the input power level strongly depends on the distance between the power transmitter and receiver. The efficiency of the DC-DC converter and LDO is improved by reducing the quiescent power consumption. This chip is implemented in 0.35 μm CMOS and the die are is 5 mm x 2.5 mm.