A 13.56MHz Wireless Power Transfer System with Dual-Output Regulated Active Rectifier for Implantable Medical Devices

In this paper, a 13.56 MHz wireless power transfer system with dual-output regulated active rectifier is developed for implantable medical devices. The rectifier employs pulse-skip modulation (PSM) to regulate two output voltages without using power consuming low dropout regulators (LDOs). The proposed automatic digital offset compensation adjusts both turn-on timing and turn-off timing to compensate the turn-on and turn-off delays of the comparator. The simulation results show that the proposed active rectifier achieves 94% efficiency. The entire wireless power transmission system including power amplifier, resonant tanks, and rectifier, has 67.2% maximum power conversion efficiency (PCE). Compared to the conventional approach with ideal LDOs, 19.2% efficiency improvement is obtained.