Class E RF amplifier design in an ultrasonic link for wireless power delivery to implanted medical devices

Abstract

Ultrasonic power transfer is a promising alternative to electromagnetic induction for providing wireless power to active implanted medical devices. In a portable ultrasonic power link for devices like cochlear implants, there is a key requirement for an inverter circuit that is capable of driving the transmitting piezoelectric transducer with high efficiency in order to maximize battery life and overall device reliability. In the following paper, a high efficiency Class E amplifier is presented for use on the transmit side of an ultrasonic transcutaneous energy transfer (UTET) link. The amplifier is characterized by a peak efficiency of 90.8% at an output power level of 293 mW and drive frequency of 1.275 MHz.

Applications of Wireless Power Transfer in Medicine: State-of-the-Art Reviews

“…Vihvelin et al developed an ultrasonic power transfer system to power implantable devices. 56 Portable ultrasonic power links require device reliability and maximized battery life, which is achieved by an inverter circuit delivering high efficiency to the transmitting piezoelectric transducer. The efficiency for the wireless ultrasonic power link is the product of each energy conversion shown in Fig.…”