Miniature bioelectronic implants promise revolutionary therapies for cardiovascular and neurological disorders. Wireless power transfer (WPT) is a significant method for miniaturization, eliminating the need for bulky batteries in today’s devices. Despite successful demonstrations of millimetric battery-free implants in animal models, the robustness and efficiency of WPT are known to degrade significantly under misalignment incurred by body movements, respiration, heart beating, and limited control of implant orientation during surgery. This article presents an omnidirectional WPT platform for millimetric bioelectronic implants, employing the emerging magnetoelectric (ME) WPT modality, and “magnetic field steering” technique based on multiple transmitter (TX) coils. To accurately sense the weak coupling in a miniature implant and adaptively control the multicoil TX array in a closed loop, we develop an active echo (AE) scheme using a tiny coil on the implant. Our prototype comprises a fully integrated 14.2 mm3 implantable stimulator embedding a custom low-power system-on-chip (SoC) powered by an ME film, a TX with a custom three-channel AE RX chip, and a multicoil TX array with mutual inductance cancellation. The AE RX achieves −161 dBm/Hz input-referred noise with 64 dB gain tuning range to reliably sense the AE signal, and offers fast polarity detection for driver control. AE simultaneously enhances the robustness, efficiency, and charging range of ME WPT. Under 90° rotation from the ideal position, our omnidirectional WPT system achieves $6.8{ \times }$ higher power transfer efficiency (PTE) than a single-coil baseline. The tracking error of AE negligibly degrades the PTE by less than 2% from using ideal control.

中文翻译：

---

用于毫米级磁电生物医学植入物的全向无线电力传输


微型生物电子植入物有望为心血管和神经系统疾病带来革命性的疗法。无线电力传输 （WPT） 是一种重要的小型化方法，消除了当今设备对笨重电池的需求。尽管在动物模型中成功展示了毫米级无电池植入物，但已知 WPT 的稳健性和效率在身体运动、呼吸、心跳和手术过程中对植入物方向的有限控制引起的错位下会显着降低。本文介绍了一个用于毫米级生物电子植入物的全向 WPT 平台，采用新兴的磁电 （ME） WPT 模式和基于多个发射器 （TX） 线圈的“磁场控制”技术。为了准确感知微型植入物中的弱耦合并在闭环中自适应地控制多线圈 TX 阵列，我们在植入物上使用微小线圈开发了一种有源回波 （AE） 方案。我们的原型包括一个完全集成的 14.2 mm3 植入式刺激器，嵌入了一个由 ME 薄膜供电的定制低功耗片上系统 （SoC）、一个带有定制三通道 AE RX 芯片的 TX 和一个具有互感抵消功能的多线圈 TX 阵列。AE RX 可实现 −161 dBm/Hz 的输入参考噪声和 64 dB 的增益调谐范围，以可靠地感应 AE 信号，并为驾驶员控制提供快速极性检测。AE 同时增强了 ME WPT 的稳健性、效率和充电范围。在从理想位置旋转 90° 的情况下，我们的全向 WPT 系统实现了比单线圈基线高 6.8 美元的功率传输效率 （PTE） $ 。与使用理想对照相比，AE 的跟踪误差使 PTE 的降低可以忽略不计地降低不到 2%。