一种低噪声心电信号采集模拟前端电路设计
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摘要
基于0.18μm CMOS工艺设计了一种由前置放大器、可变增益放大器和G_m-C低通滤波器组成的低噪声心电信号采集前端电路。前置放大器采用了电容耦合结构,其中运算放大器的输入端采用了互补P/NMOS结构以降低1/f噪声的影响,并通过改进的RC密勒补偿技术提高了放大器的响应速度,而可变增益放大器则通过可调电容阵列实现了增益的均匀可调。仿真实验结果表明,所设计的心电信号采集前端电路的总电流仅为4μA,带宽为0.016～162 Hz,增益为40～58 dB且均匀可调,等效输入噪声为1.3μV_(rms)(0.1～200 Hz)。
A low-noise analog front-end( AFE) circuit for ECG signal acquisition is designed based on 0. 18 μm CMOS technology,including a preamplifier,a variable gain amplifier and a G_m-C low-pass filter. The acapacitively-coupled structure is applied in the preamplifier,and the operational amplifier uses the structure of complementary( P/NMOS) to reduce 1/f noise,and the response speed is improved by an improved Miller compensation technique. The variable gain amplifier achieves a continuous tunable gain with an adjustable capacitance array. Simulation results show that the AFE circuit consumes only 4 μA current and achieves a variable gain from 40 dB to 58 dB in the band from 0. 016 Hz to 162 Hz with the input referred noise of 1. 3 μV_(rms)(0. 1 Hz ～ 200 Hz).
A low-noise analog front-end( AFE) circuit for ECG signal acquisition is designed based on 0. 18 μm CMOS technology,including a preamplifier,a variable gain amplifier and a G_m-C low-pass filter. The acapacitively-coupled structure is applied in the preamplifier,and the operational amplifier uses the structure of complementary( P/NMOS) to reduce 1/f noise,and the response speed is improved by an improved Miller compensation technique. The variable gain amplifier achieves a continuous tunable gain with an adjustable capacitance array. Simulation results show that the AFE circuit consumes only 4 μA current and achieves a variable gain from 40 dB to 58 dB in the band from 0. 016 Hz to 162 Hz with the input referred noise of 1. 3 μV_(rms)(0. 1 Hz ～ 200 Hz).
引文
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[2]ZOU Xiaodan,XU Xiaoyuan,YAO Libin,et al.A 1 V450 nW fully integrated programmable biomedical sensor interface chip[J].IEEE Journal of Solid-State Circuits,2009,44(4):1067-1077.
[3]YONATAN K,HANI S,BAKER M,et al.A sub-μW biopotential front end in 65 nm CMOS[C]∥IEEE International Conference on very Large Scale Integration.2017:1-4.
[4]HASAN M N,LEE K S.A wide linear output range biopotential amplifier for physiological measurement frontend[J].IEEE Transactions on Instrumentation and Measurement,2015,64(1):120-131.
[5]LEE H C,WANG J B,JUANG K H,et al.An ECG frontend circuit with single power supply[C]∥IEEE International Conference on Consumer Electronics.2015:270-271.
[6]HARRISON R,CHARLES C.A low-power low-noise CMOSamplifier for neural recording applications[J].IEEE Journal of Solid-State Circuits,2003,38(6):958-965.
[7]ZHANG Hao,LI Ye.A 470 nA performance-enhanced instrumental amplifier for bio-signal acquisition[C]∥IEEEBiomedical Circuits and Systems Conference.2016:288-291.
[8]YANG H C,ALLSTOT D J.Modified modeling of Miller compensation for two-stage operational amplifiers[C]∥IEEE International Sympoisum on Circuits and Systems.1991:2557-2560.
[9]KUO L T,HOU C C,WU M H,et al.A 1 V 9μA analog front end with compressed sensing for electrocardiogram monitoring[C]∥IEEE Asian Solid State Circuits Conference.2015:1-4.
[10]HUANG Feng,LIN Ke,GAO Fang,et al.A 1.2 V 7.2μWECG AFE with continuous time self-calibration filters[C]∥IEEE 11th International Conference on ASIC.2015:1-4.
[11]CHENG C H,CHEN Z X,WU C Y.A 16-channel CMOSchopper-stabilized analog front-end acquisition circuits for ECo G detection[C]∥IEEE International Symposium on Circuits and Systems.2017:1-4.