A 13.56MHz wireless power transfer system with reconfigurable resonant regulating rectifier and wireless power control for implantable medical devices

A 13.56MHz wireless power transfer system with a 1X/2X reconfigurable resonant regulating (R3) rectifier and wireless power control for biomedical implants is presented. Output voltage regulation is achieved through two mechanisms: the local PWM loop of the secondary side controls the duty cycle of switching the rectifier between the 1X and 2X modes; and to adapt to load and coupling variations, the duty cycle information encoded in Manchester code is fed back wirelessly to the primary side using a novel backscattering uplink technique to adjust the transmitter power of the primary coil. The primary transmitter and the secondary R3 rectifier are fabricated in 0.35μm CMOS process. The measured maximum received power and receiver efficiency are 102mW and 92.6%, respectively.