A 13.56 MHz Wireless Power Transfer System with Bidirectional Data Link and Closed-loop Power Control for Implantable Neuromuscular Stimulator

Abstract

This paper presents a 13.56 MHz wireless power transfer (WPT) system for fully implantable neuromuscular stimulator. Bidirectional wireless data link and closed-loop power control functions are incorporated into the WPT system for stable power delivery to the implant. The external power transmitter (PTX) module includes a DC-DC converter and a Class-E power amplifier (PA) for tunable high efficiency power transmission. The forward link command is modulated on the carrier by amplitude-shift keying (ASK) modulation. The implantable power receiver (PRX) module receives power and data simultaneously from the coupling inductors. PTX and PRX are implemented with discrete components and integrated circuit, respectively. Measurement results showed over 90% Class-E PA efficiency and 42% PRX power conversion efficiency.