Integrated Chip Power Receiver for Wireless Bio-implantable Devices

Wireless bio-medical devices employ inductive link as medium for transfer of energy between the external source and the implant. But, the inductive power picked by receiver results in high voltage, that may largely exceed the voltage compliance of low voltage integrated chips. The high voltage at the receiver is due to high load impedance offered by electrodes within the implant. To limit the magnitude of induced voltage, majority of the low voltage circuits use power inefficient methods like voltage clippers and shunt regulators. Therefore, to overcome voltage limitation and to enhance power efficiency, a power receiver topology based on step-down approach is designed and implemented for input voltage as high as 30 V. The implemented design consists of rectifier and series voltage regulator. In addition a battery charger circuit that ensures safe and reliable charging of the implant battery is designed and tested. The proposed design is fabricated in 0.35 mu m high voltage BCD foundry. Rectifier and regulator power efficacy are analyzed based on simulation and measurement results.