Cho Hyungjoo, Suh Ji-Hoon, Kim Chul, Ha Sohmyung, Je Minkyu
IEEE Trans Biomed Circuits Syst. 2022 Oct;16(5):852-866. doi: 10.1109/TBCAS.2022.3194278. Epub 2022 Nov 30.
This paper presents an intra-body power transfer (IBPT) system that can deliver power greater than 1 mW across an on-body distance of 160 cm. A system simulation model is built for the characterization of the channel and optimization of the power transfer. Our system analysis and experimental validation demonstrate that 1 MHz is an optimal carrier frequency for IBPT in terms of power delivered to the load (PDL) and power efficiency (PE). Prototype TX and RX boards were built, and an IC was fabricated in a 180-nm CMOS process for the RX. The proposed RX IC consists of a voltage doubler (VD) and a charge pump (CP) to obtain a sufficiently high voltage conversion ratio (VCR). Among various rectifier topologies, the VD is the optimal topology for the power receiver front-end because the parasitic ground coupling capacitances, which inevitably exist in the IBPT system, act as an inherent input-coupling capacitance for the VD. The implemented VD utilizes a dynamic V compensation (DVC) for its diode components. Compared to the conventional static V compensation (SVC), DVC in the VD reduces the reverse leakage current of the diode, thus maximizing the power conversion efficiency (PCE) and VCR. In addition, the PDL is enhanced by inserting an inductor on the TX board. It reduces the backward-path impedance without increasing the RX volume, boosting the PDL by up to 9.9 times compared to the PDL without the inductor insertion. The proposed IBPT system delivers up to 178.8 μW of power at 11.7% of maximum power efficiency with 3.3-V DC output voltage and even 1.385 mW of power with the inductor insertion, supporting various biomedical wearable sensors, such as ECG sensor modules.
本文介绍了一种体内功率传输（IBPT）系统，该系统能够在160厘米的身体距离上传输大于1毫瓦的功率。构建了一个系统仿真模型，用于表征信道和优化功率传输。我们的系统分析和实验验证表明，就传输到负载的功率（PDL）和功率效率（PE）而言，1兆赫兹是IBPT的最佳载波频率。制作了原型发射（TX）和接收（RX）板，并采用180纳米CMOS工艺为RX制造了一个集成电路。所提出的RX集成电路由一个倍压器（VD）和一个电荷泵（CP）组成，以获得足够高的电压转换率（VCR）。在各种整流器拓扑结构中，VD是功率接收器前端的最佳拓扑结构，因为IBPT系统中不可避免存在的寄生接地耦合电容充当了VD的固有输入耦合电容。所实现的VD对其二极管组件采用了动态V补偿（DVC）。与传统的静态V补偿（SVC）相比，VD中的DVC降低了二极管的反向漏电流，从而使功率转换效率（PCE）和VCR最大化。此外，通过在TX板上插入一个电感来提高PDL。它在不增加RX体积的情况下降低了反向路径阻抗，与未插入电感时的PDL相比，PDL提高了9.9倍。所提出的IBPT系统在3.3伏直流输出电压下，以11.7%的最大功率效率提供高达178.8微瓦的功率，插入电感时甚至可提供1.385毫瓦的功率，支持各种生物医学可穿戴传感器，如心电图传感器模块。
