An 1.97μ, W/Ch 65nm-CMOS 8-Channel Analog Front-End Acquisition Circuit with Fast-Settling Hybrid DC Servo Loop for EEG Monitoring

Pin Wen Chen, Chi Wei Huang, Chung-Yu Wu

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations

Abstract

In this paper, a 65nm-CMOS 8-channel Analog Front-End (AFE) acquisition circuit is designed and fabricated for long term EEG monitoring. The Capacitively-Coupled Chopper Instrumentation Amplifier (CCCIA) with chopper modulation is used to amplify input EEG signals and suppress flicker noise. To realize low high-pass corner and large Electrode DC Offset (EDO) rejection ability, a fast-settling Hybrid DC Servo Loop (HDSL) is proposed here. It contains Digital DSL (DDSL) and Analog DSL (ADSL) to achieve better trade-off among power consumption, area, and hardware complexity. An energy-efficient 10-bit SAR ADC with offset-calibration comparator is integrated for accurate A/D conversion. The chip is fabricated in 65nm CMOS technology. The measured overall power dissipation of the acquisition circuit is 1.97μW per channel. The input-referred noise of AFE Amplifier (AFEA) is 0.7μV in pass band, and the Noise Efficient Factor (NEF) of the CCCIA is 1.99. The measured HDSL calibration time is 125ms. The fabricated SAR ADC has the power consumption of 0.85μW under 1V supply and the SNDR of 59.8dB at 100kS/s with the Nyquist input frequency. This chip can record EEG signals successfully and the recorded signal has been verified by NeruScan SynAmps RT 64-channel amplifiers.

Original languageEnglish
Title of host publication2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781538648810
DOIs
StatePublished - 26 Apr 2018
Event2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018 - Florence, Italy
Duration: 27 May 201830 May 2018

Publication series

NameProceedings - IEEE International Symposium on Circuits and Systems
Volume2018-May
ISSN (Print)0271-4310

Conference

Conference2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018
CountryItaly
CityFlorence
Period27/05/1830/05/18

Keywords

  • DC servo loop
  • SAR ADC
  • analog front-end
  • chopping
  • electroencephalogram (EEG)
  • low noise

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