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

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 effectively addresses the conventional tradeoffs among power delivered to the load (PDL), data rate (DR), and power transfer efficiency (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 sensitivity by amplifying envelope differences, 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\times $compared to prior state-of-the-art systems, employing a single inductive link.