A 124 dB dynamic range sigma-delta modulator applied to non-invasive EEG acquisition using chopper-modulated input-scaling-down technique  

作　　者：Kaiquan CHEN Mingyi CHEN Longlong CHENG Liang QI Guoxing WANG Yong LIAN 

机构地区：[1]Department of Micro/Nano Electronics,Shanghai Jiao Tong University,Shanghai 200240,China [2]China Electronic Cloud Brain(Tianjin)Technology Co.,Ltd.,Tianjin 300309,China

出　　处：《Science China(Information Sciences)》2022年第4期19-33,共15页中国科学（信息科学）（英文版）

基　　金：supported by National Natural Science Foundation of China(Grant No.62174109).

摘　　要：With the advancement of brain science in recent years,the non-invasive brain-computer interfaces(BCIs)based on electroencephalogram(EEG)acquisition have been widely adopted in various brain-inspired applications.The acquisition of multi-channel microvolts EEG signals corrupted by the motion artifacts(MAs)of up to several volts poses enormous challenges to the design of analog front-end(AFE),especially the analog-to-digital converter(ADC),which is necessary to achieve low noise,wide dynamic range(DR),high accuracy as well as low power.In this paper,a wide DRΣ∆modulator with chopper-modulated inputscaling-down(CM-ISD)technique has been proposed to deal with large input offset while extending dynamic range.Fabricated in 180 nm CMOS technology,the prototype occupies a core area of 0.32 mm^(2).With a 40 Hz input signal and 125 Hz Nyquist bandwidth,the measured signal-to-noise ratio(SNR)and signalto-noise and distortion ratio(SNDR)are 117 and 110 dB,respectively.Thanks to the proposed CM-ISD technique,the modulator is capable of withstanding a full-scale(4.5 V_(pp))input whereas the measured DR has been extended from 99 to 124 dB.The power consumption is 2.75 mW under 5 V supply voltage,corresponding to 170.6 dB Schreier figure-of-merit(FoMS).The multi-channel EEG acquisition has been demonstrated based on the proposed modulator,showing its potential in advanced non-invasive BCI systems.

关 键 词：analog-to-digital converter(ADC) Σ∆modulator brain computer interface(BCI) electroencephalogram(EEG) dynamic range(DR) motion artifacts(MA) 

分 类 号：TN911.7[电子电信—通信与信息系统] R741.044[电子电信—信息与通信工程]