Powering mm-Size Wireless Implants for Brain-Machine Interfaces
Powering mm-Size Wireless Implants for Brain-Machine Interfaces
复制标题
为脑机接口的毫米级无线植入物供电
DOI：
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发表时间：
2011
期刊：
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通讯作者：
M. Mark
中科院分区：
文献类型：
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作者：
M. Mark
在过去的几年里，基于微电极阵列的脑机接口（BMI）已被证明有可能大大改善患有脊髓损伤或肢体丧失等衰弱疾病的人的生活质量。BMI系统最关键的部分之一是神经传感器。理想情况下，它被植入头骨下方，从大脑读取神经信号，并将其无线传输到头骨外的接收器。对这种传感器的电子器件的要求非常严格，特别是在尺寸和功耗方面。理想情况下，植入的传感器节点的整体尺寸受传感器本身尺寸的限制，而不是受电子器件和电源的限制。这项工作调查的植入物的尺寸范围从10毫米的10毫米到1毫米的1毫米的供电选项。无线电力传输被确定为最有前途的选择这样做，并进行了详细的调查。它示出，对于一个给定的植入天线的大小，外部天线和操作频率的最佳组合存在，最大限度地减少整体链路损耗。结合由于健康问题对最大发射和接收功率的限制，推导出mm尺寸植入物可用的最大功率随尺寸的变化。两种不同的AC到DC转换电路的拓扑结构，涵盖预期的输入功率和频率范围，进行了详细分析，并给出了每一个设计准则。最后，1毫米3的无线供电的神经应答器的概念验证实施。它在空气和动物中进行了测试，并提供足够的额外直流电源为神经传感器前端供电，同时支持2 Mbps的无线电链路。所提出的标签是迄今为止报道的最小的无线神经标签，并证明了远程供电的毫米级无线神经植入物的可行性。
Over the last couple of years, Brain-Machine Interfaces (BMI) based on microelectrode arrays have been shown to have the potential to substantially improve the quality of life for people suffering from debilitating conditions such as spinal cord injuries or limb loss. One of the most critical parts of a BMI system is the neural sensor. It is ideally implanted underneath the skull, reads out neural signals from the brain and transmits them wirelessly to a receiver outside the skull. The requirements on the electronics of such a sensor are extremely stringent, especially with respect to size and power consumption. Ideally, the overall size of the implanted sensor node is limited by the size of the sensor itself, rather than the electronics and the power source. This work investigates powering options for implants of sizes ranging from 10 mm by 10 mm down to 1 mm by 1 mm. Wireless power transfer is identified as the most promising option of doing so and is investigated in detail. It is shown, that for a given implant antenna size, an optimum combination of external antenna and frequency of operation exists that minimizes the overall link loss. In combination with limitations on the maximum transmit and received power due to health concerns, the maximum power available to mm-size implants as a function of size is derived. Two different AC-to-DC conversion circuit topologies, covering the expected input power and frequency range, are analyzed in detail and design guidelines for each are given. Finally, a 1 mm 3 proof-of-concept implementation of a wirelessly powered neural transponder is presented. It was tested in air and in animal and provides enough extra DC power to power a neural sensor front-end while supporting a 2 Mbps radio link. The presented tag is the smallest wireless neural tag reported to date and prooves the feasibility of remotely powered mm-size wireless neural implants.