A 13.56 MHz Current-Mode Wireless Power Receiver With Energy-Investment Capability

A 13.56 MHz current-mode wireless power receiver with energy-investment capability is presented. An investing voltage controller and a zero-crossing current switching controller are presented to control the switching timing of the power MOSFETs. Both the controllers use the sample-and-hold circuits and the digital controlled delay lines to tolerate the process variations. The highest operation frequency of the controllers is 6.78 MHz. This chip is fabricated in a 0.18-μm CMOS process. It achieves a peak power conversion efficiency of 67.1% when the input power is 6 mW.