IEEE Trans Biomed Circuits Syst. 2023 Oct;17(5):1111-1124. doi: 10.1109/TBCAS.2023.3301493. Epub 2023 Nov 21.
This article presents a multichannel EEG/BIOZ acquisition application specific integrated circuit (ASIC) with 4 EEG channels and a BIOZ channel, a switch resistor low-pass filter (SR-LPF). Each EEG channel includes a frontend, and a 4-channel multiplexed analog-to-digital converter (ADC), while the BIOZ channel features a pseudo sine current generator and a pair of readout paths with multiplexed SR-LPF and ADC. The ASIC is designed for size and power minimization, utilizing a 3-step ADC with a novel signal-dependent low power strategy. The proposed ADC operates at a sampling rate of 1600 S/s with a resolution of 15.2 bits, occupying only 0.093 mm. With the help of the proposed signal-dependent low-power strategy, the ADC's power dissipation drops from 32.2 μW to 26.4 μW, resulting in an 18% efficiency improvement without performance degradation. Moreover, the EEG channels deliver excellent noise performance with a NEF of 7.56 and 27.8 nV/√Hz at the expense of 0.16 mm per channel. In BIOZ measurement, a 5-bit programmable current source is used to generate pseudo sine injection current ranging from 0 to 22 μApp, and the detection sensitivity reaches 2.4 mΩ/√Hz. Finally, the presented multichannel EEG/BIOZ acquisition ASIC has a compact active area of 1.5 mm in an 180nm CMOS technology.
本文提出了一种具有 4 个 EEG 通道和 1 个 BIOZ 通道的多通道 EEG/BIOZ 采集专用集成电路（ASIC），以及一个开关电阻低通滤波器（SR-LPF）。每个 EEG 通道包括前端和一个 4 通道复用模拟数字转换器（ADC），而 BIOZ 通道则具有一个伪正弦电流发生器和一对带有复用 SR-LPF 和 ADC 的读出通道。该 ASIC 旨在最小化尺寸和功耗，采用具有新型信号相关低功耗策略的 3 步 ADC。所提出的 ADC 以 1600 S/s 的采样率工作，分辨率为 15.2 位，仅占用 0.093mm²。借助所提出的信号相关低功耗策略，ADC 的功耗从 32.2μW 降低到 26.4μW，在不影响性能的情况下效率提高了 18%。此外，EEG 通道在每个通道占用 0.16mm²的情况下，提供了出色的噪声性能，噪声等效带宽（NEF）为 7.56 和 27.8nV/√Hz。在 BIOZ 测量中，使用 5 位可编程电流源生成范围为 0 至 22μApp 的伪正弦注入电流，检测灵敏度达到 2.4mΩ/√Hz。最后，所提出的多通道 EEG/BIOZ 采集 ASIC 在 180nmCMOS 技术中具有 1.5mm²的紧凑有源面积。
