A 2.36μW/Ch CMOS 8-Channel EEG Acquisition Unit with Input Protection Circuits for Applications under Transcranial Direct Current Stimulation

Chung-Yu Wu, Chi Wei Huang, Tzung Lin Tsai*

*Corresponding author for this work

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

3 Scopus citations

Abstract

A 0.18um-CMOS 8-channel EEG acquisition unit with input protection circuits is designed and fabricated for EEG monitoring under the transcranial direct current stimulation (tDCS). The capacitively-coupled chopper instrumentation amplifier (CCCIA) with chopper modulation is used to suppress flicker noise and amplify input EEG signals. To filter out high frequency noise with high linearity, the switched-capacitor low-pass filter (SC-LPF) is proposed. The switched-capacitor amplifier (SC-Amp) is also proposed to drive ADC capacitor array. The input protection circuit (IPC) is implemented by I/O device to keep internal circuits from overstress and artifacts from the tDCS. A 10-bit SAR ADC with offset-calibration comparator is integrated for accurate ADC conversion. The fabricated EEG acquisition unit has programmable gain 57.5/67.6/78.5dB. The measured power dissipation of a single CCCIA circuit is 2.36μW per channel. The measured recovery time is 7.5ms after the tDCS stimulation. It has been verified that the designed chip can record real EEG signals.

Original languageEnglish
Title of host publicationBioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781509006175
DOIs
StatePublished - Oct 2019
Event2019 IEEE Biomedical Circuits and Systems Conference, BioCAS 2019 - Nara, Japan
Duration: 17 Oct 201919 Oct 2019

Publication series

NameBioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings

Conference

Conference2019 IEEE Biomedical Circuits and Systems Conference, BioCAS 2019
CountryJapan
CityNara
Period17/10/1919/10/19

Keywords

  • electroencephalogram (EEG)
  • HD-TDCS
  • input protection
  • low noise
  • switched-capacitor

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