The CMOS design of a high-efficiency transcutaneous power and data system

This paper presents a proposed design for transcutaneous inductive powering links with “suspended-carrier”. The design used to transfer power and data to the implanted devices.This work describes the implementation of a 0.35μm CMOS integrated circuit using 3.3v supply dedicated to cochlear prosthesis. In the wireless biomedical implants the carrier frequency, which represent the resonant frequency of the power amplifier is limited to a few tens of megahertz because of the incremental tissue loss and risk of tissue damage at higher frequencies. The system uses synchronous frequency-shift-keyed (FSK) modulation, with 5/10 MHz carrier frequencies, based on the class E power oscillator. The Class-E power oscillator has been identified as a highly-efficient transmitter circuit for use as a means of transferring power to an implant. Although the high-Q nature of this topology makes rapid modulation difficult, it is feasible to use synchronous frequency-shift-keyed (FSK) modulation of the Class-E circuit thereby combining an efficient power transmitter with a high speed data link. Using this method, the transmitter can be modulated on a cycle-by-cycle basis with little to no additional power loss.