Chapter 19 - Efficient wireless power transfer system for biomedical applications

Abstract

Current ultra-low-power biomedical instruments possess a wireless power transfer (WPT) system using an inductive link, which provides an increasingly attractive method to deliver power to biomedical implants safely. Biomedical implanted devices are becoming popular in a wide range of areas, such as cardiac pacemakers, retinal prosthesis, cochlear implants, defibrillators, smart orthopedic implants, artificial hearts, etc. The system consists of two primary coils, such as a transmitter coil placed at the outside of the human body and receiver coil placed inside the body. The inductive link has a function for desirable power transmission from the transmitter circuit to the receiver circuit without the use of the battery. A brief design was enlightened for evaluation of the performance of the inductive link, with high transmission efficiency. The transmitter and receiver circuit included an oscillator, driver, and a Class-E power amplifier as the power conditioning units for the WPT system. Finally, the challenges, along with solutions, are highlighted in developing an optimal design of the inductive link for implantable devices.