Resistive Matching using an AC Boost Converter for Efficient Ultrasonic Wireless Power Transfer

Abstract

This paper presents a method to increase the power conversion of ultrasonic receivers in implantable medical devices. A perfect complex conjugate match between the piezo-electric receiver and the power conversion circuit is required for maximum power transfer. A boost converter in front of the rectifier enables a close to perfect resistive match. The boost converter transforms the AC voltage into a pulse width modulated square wave voltage. This saves an extra impedance transformation between the receiver and the rectifier. From circuit simulation results, it follows that this new method has the highest efficiency compared with prior art.