A Wireless Power and Data Transfer System for Medical Implants Using a Miniaturized Inductive Link With Frequency-Splitting Enhancement

Abstract

This article presents an enhanced-frequency- splitting-based wireless power and data transfer (EFS-WPDT) system that simultaneously delivers power and forward data over a compact inductive link. For data transmission, the proposed system employs frequency-shift keying (FSK) based on frequency-splitting enhancement (FSE), which is enabled by dynamic link-load isolation (LLI) and time-interleaved LC resonance. This approach e ffectively addresses the conventional tradeoffs among power delivered to the load (PDL), data rate (DR), and power transfer e fficiency (PTE). The dynamic LLI decouples the load during each resonance phase, which is critical for enabling FSE, and is implemented using a quasi- resonant boost converter (QRBC) that provides a boosted and regulated output voltage. For time-interleaved operation, reliable peak detection is achieved by a body-tuned peak detector (BTPD), which maintains accurate timing across varying link conditions. A frequency-to-amplitude converter enhances sensi- tivity by amplifying envelope di fferences, enabling robust data demodulation even in the miniaturized link. The presented ICs, fabricated in a 180-nm bipolar-CMOS-DMOS (BCD) process, simultaneously achieve 60.2% overall PTE, 43.4-mW PDL, and 1-Mb/s DR with a sub-centimeter receiver (RX) coil. As a result, the figure of merit (FoM) for data transmission is improved to a level comparable to previous works using centimeter-scale links, while the FoM for power delivery is improved by 2 .5× co