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arXiv · 2506.07710

A 40.68-MHz, 200-ns-Settling Active Rectifier and TX-Side Load Monitoring for Minimizing Radiated Power in Biomedical Implants

Ronald Wijermars·Yi-Han Ou-Yang·Sijun Du·Dante Gabriel Muratore
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Abstract

This letter describes a 40.68 MHz wireless power transfer receiver for implantable applications focused on minimizing tissue heating. The system features a novel power radiated efficiency optimization strategy and a fast-settling active rectifier that maintains high efficiency during load and link variations required for downlink communication. The power radiated efficiency optimization explicitly reduces tissue heating while enabling transmitter-side load monitoring for closed-loop control. The active rectifier was fabricated in 40nm CMOS and achieves a voltage conversion ratio of 93.9% and a simulated power conversion efficiency of 90.1% in a 0.19 $mm^2$ area, resulting in a 118 mW/$mm^2$ power density while integrating the resonance and filter capacitors. The worst-case settling of the on- and off-delay compensation in the active rectifier is 200 ns, which is the fastest reported to date.

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Ronald Wijermars, Yi-Han Ou-Yang, Sijun Du, Dante Gabriel Muratore. 2025-06-09. A 40.68-MHz, 200-ns-Settling Active Rectifier and TX-Side Load Monitoring for Minimizing Radiated Power in Biomedical Implants. https://arxiv.org/abs/2506.07710

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