Power-oscillator based high efficiency inductive power-link for transcutaneous power transmission

Transcutaneous power transmission is a critical issue for long term reliable operation of implantable systems. This paper reports a power-oscillator based inductive power link to power up any implantable unit inside the human body. Instead of using power amplifier which requires high drive requirement, two power-oscillator based inductive powering schemes have been presented to achieve high link efficiency. The first scheme utilizes a class-E power oscillator whereas the second scheme uses a differential cross-coupled power oscillator to drive the inductive link. Resonant inductive link has been used to achieve better link efficiency. Simulation results indicate that for a coupling coefficient of 0.45, the class-E power-oscillator based scheme shows a link efficiency of 66% and the differential cross-coupled power-oscillator based scheme shows more than 90% link efficiency. The system has been designed using 0.5-μm standard CMOS process and both of the systems can handle more than 10 mW of power which is adequate for safe operation of biomedical implants.