The application of Wireless Power Transmission (WPT) has attracted more and more attention, but the energy efficiency cannot be high due to the inevitable loss. Energy efficient WPT is increasingly demanded especially in implantable devices due to their wireless inefficiency nature. In addition, many implantable devices include digital circuits such as a Microcontroller Unit (MCU) in which the supply voltage may fluctuate severely with the driving clock of digital circuits switches between ground (Gnd) and supply voltage (Vdd), since the power transmitted wirelessly is limited, and the system may even cut off under wireless charging conditions. Therefore, the load regulation is also required in a WPT system. This paper presents a WPT system with load regulation and optimized antenna design for implantable devices, for which measurement results show that the maximum transmission efficiency can reach 79.3% and it can still necessitate a large dynamic load current range. When the load current is switched between 12 uA and 5 mA, the overshoot and undershoot of the output voltage are 150 mV and 80 mV, respectively. Finally, several state-of-the-art WPT applications in biomedical devices are introduced.

中文翻译：

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一种具有负载调节功能的植入式设备无线电能传输系统

无线电力传输（WPT）的应用越来越受到关注，但由于不可避免的损耗，能量效率不能高。由于无线效率低下的特性，尤其是在可植入设备中，对节能 WPT 的需求越来越大。此外，许多可植入设备包括数字电路，例如微控制器单元 (MCU)，其中电源电压可能会随着数字电路的驱动时钟在接地 (Gnd) 和电源电压 (Vdd) 之间切换而发生剧烈波动，因为电源以无线方​​式传输限制，系统甚至可能在无线充电条件下断电。因此，WPT 系统也需要负载调节。本文介绍了一种具有负载调节和优化天线设计的 WPT 系统，用于植入式设备，测量结果表明，最大传输效率可达79.3%，但仍需要较大的动态负载电流范围。当负载电流在 12 uA 和 5 mA 之间切换时，输出电压的过冲和下冲分别为 150 mV 和 80 mV。最后，介绍了生物医学设备中几种最先进的 WPT 应用。