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 (R
³
) 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 R
³
rectifier are fabricated in 0.35µm CMOS process. The measured maximum received power and receiver efficiency are 102mW and 92.6%, respectively.