Apple Incorporated, Cupertino, CA 95014, USA.
Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, USA.
Sensors (Basel). 2018 Jan 17;18(1):263. doi: 10.3390/s18010263.
This paper presents a minimally-invasive neural interface for distributed wireless electrocorticogram (ECoG) recording systems. The proposed interface equips all necessary components for ECoG recording, such as the high performance front-end integrated circuits, a fabricated flexible microelectrode array, and wireless communication inside a miniaturized custom-made platform. The multiple units of the interface systems can be deployed to cover a broad range of the target brain region and transmit signals via a built-in intra-skin communication (ISCOM) module. The core integrated circuit (IC) consists of 16-channel, low-power push-pull double-gated preamplifiers, in-channel successive approximation register analog-to-digital converters (SAR ADC) with a single-clocked bootstrapping switch and a time-delayed control unit, an ISCOM module for wireless data transfer through the skin instead of a power-hungry RF wireless transmitter, and a monolithic voltage/current reference generator to support the aforementioned analog and mixed-signal circuit blocks. The IC was fabricated using 250 nm CMOS processes in an area of 3.2 × 0.9 mm² and achieved the low-power operation of 2.5 µW per channel. Input-referred noise was measured as 5.62 µV for 10 Hz to 10 kHz and ENOB of 7.21 at 31.25 kS/s. The implemented system successfully recorded multi-channel neural activities in vivo from a primate and demonstrated modular expandability using the ISCOM with power consumption of 160 µW.
本文提出了一种用于分布式无线脑电（ECoG）记录系统的微创神经接口。所提出的接口配备了 ECoG 记录所需的所有必要组件，例如高性能前端集成电路、制造的柔性微电极阵列以及小型化定制平台内的无线通信。多个接口系统可以部署以覆盖目标大脑区域的广泛范围，并通过内置的皮肤内通信（ISCOM）模块传输信号。核心集成电路（IC）由 16 通道、低功耗推挽双栅前置放大器、具有单时钟引导开关和时滞控制单元的通道内逐次逼近寄存器模数转换器（SAR ADC）、用于通过皮肤进行无线数据传输而不是使用耗电的射频无线发射器的 ISCOM 模块以及用于支持上述模拟和混合信号电路块的单片电压/电流基准发生器组成。该 IC 使用 250nm CMOS 工艺制造，面积为 3.2×0.9mm²，实现了每通道 2.5µW 的低功耗操作。在 10Hz 至 10kHz 时，输入参考噪声测量为 5.62µV，在 31.25kS/s 时 ENOB 为 7.21。所实现的系统成功地从灵长类动物体内记录了多通道神经活动，并通过使用 ISCOM 展示了模块化可扩展性，其功耗为 160µW。
