A 256-Channel Actively-Multiplexed µECoG Implant with Column-Parallel Incremental $DeltaSigma$ ADCs Employing Bulk-DACs in 22-nm FDSOI Technology
A 256-Channel Actively-Multiplexed µECoG Implant with Column-Parallel Incremental $DeltaSigma$ ADCs Employing Bulk-DACs in 22-nm FDSOI Technology
复制标题
具有列并行增量 $DeltaSigma$ ADC 的 256 通道主动复用 µECoG 植入，采用 22 nm FDSOI 技术中的 Bulk-DAC
DOI：
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发表时间：
2022
期刊：
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通讯作者：
C. Lopez
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作者：
Xiaohua Huang;Horacio Londoño;M. Ballini;C. Hoof;Jan Genoe;S. Haesler;Georges G. E. Gielen;N. V. Helleputte;C. Lopez
脑皮质电图（ECoG）记录是一种非穿透性电生理技术，在空间分辨率、脑覆盖和侵入性bb0之间取得了很好的平衡。由于这个原因，它被广泛用于神经疾病的诊断，并有望用于假肢的应用。尽管ECoG电极直到最近都相当大（直径约4mm），但一些研究表明，微尺度电极（直径< 1mm）更适合于研究皮质病理学和实施神经假体[2]。设计灵活、高密度的$mumathsf{ECoG}$阵列具有挑战性，因为每个电极都必须单独寻址，从而导致布线瓶颈。因此，无源μ ECoG阵列的电极数量有限，空间覆盖率较差。相比之下，主动$mumathsf{ECoG}$阵列的出现提供了更高的空间覆盖率和更好的空间分辨率。最突出的有源阵列[4]采用硅纳米膜晶体管复用电极，显著减少了信号路由。然而，该阵列中的源从动器严重限制了其噪声性能。此外，多路复用的$mumathsf{ECoG}$阵列对读出IC （ROIC）提出了额外的设计挑战：i)与常规非多路复用的ROIC[3]相比，需要至少N倍的带宽（BW）（其中N:1为多路复用比）；ii) N个电极的电极直流偏置（EDOs）是调制的，不能用传统的交流耦合或直流伺服回路（DSLs）去除；iii)需要足够低的噪声来补偿由电极复用引起的噪声混叠。
Electrocorticography (ECoG) recording is a non-penetrating electrophysiology technique that achieves a good balance between spatial resolution, brain coverage and invasiveness [1]. For this reason, it is widely used for the diagnosis of neural disorders and holds promise for prosthetic applications. Although ECoG electrodes have been until recently quite large (~4mm diameter), several studies have shown that micro-scale electrodes (< 1mm diameter) are better suited for studying cortical pathology and implementing neural prostheses [2]. The design of flexible, high-density $mumathsf{ECoG}$ arrays is challenging since every electrode must be individually addressed, resulting in a wiring bottleneck. Therefore, passive µECoG arrays have a limited electrode count and suffer from poor spatial coverage [3]. In contrast, active $mumathsf{ECoG}$ arrays have emerged to provide higher spatial coverage with better spatial resolution. The most prominent active array [4] uses Si nanomembrane transistors to multiplex the electrodes and significantly reduce the signal routing. However, the source follower in this array severely limits its noise performance. Moreover, multiplexed $mumathsf{ECoG}$ arrays impose additional design challenges on the readout IC (ROIC): i) compared to regular non-multiplexed ROICs [3], at least N times higher bandwidth (BW) is required (where N:1 is the multiplexing ratio); ii) the electrode DC offsets (EDOs) from N electrodes are modulated and cannot be removed with traditional AC coupling or DC servo loops (DSLs); and iii) sufficiently low noise is needed to compensate for the noise aliasing caused by the electrode multiplexing.