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

doi:10.1109/BIOCAS.2019.8919120

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 proceeding › Conference contribution › peer-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 language	English
Title of host publication	BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings
Publisher	Institute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)	9781509006175
DOIs	https://doi.org/10.1109/BIOCAS.2019.8919120
State	Published - Oct 2019
Event	2019 IEEE Biomedical Circuits and Systems Conference, BioCAS 2019 - Nara, Japan Duration: 17 Oct 2019 → 19 Oct 2019

Publication series

Name	BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings

Conference

Conference	2019 IEEE Biomedical Circuits and Systems Conference, BioCAS 2019
Country	Japan
City	Nara
Period	17/10/19 → 19/10/19

Keywords

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

Access to Document

10.1109/BIOCAS.2019.8919120

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Wu, C-Y., Huang, C. W., & Tsai, T. L. (2019). A 2.36μW/Ch CMOS 8-Channel EEG Acquisition Unit with Input Protection Circuits for Applications under Transcranial Direct Current Stimulation. In BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings [8919120] (BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/BIOCAS.2019.8919120

Wu, Chung-Yu ; Huang, Chi Wei ; Tsai, Tzung Lin. / A 2.36μW/Ch CMOS 8-Channel EEG Acquisition Unit with Input Protection Circuits for Applications under Transcranial Direct Current Stimulation. BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings. Institute of Electrical and Electronics Engineers Inc., 2019. (BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings).

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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.",

keywords = "electroencephalogram (EEG), HD-TDCS, input protection, low noise, switched-capacitor",

author = "Chung-Yu Wu and Huang, {Chi Wei} and Tsai, {Tzung Lin}",

year = "2019",

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doi = "10.1109/BIOCAS.2019.8919120",

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series = "BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings",

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Wu, C-Y, Huang, CW & Tsai, TL 2019, A 2.36μW/Ch CMOS 8-Channel EEG Acquisition Unit with Input Protection Circuits for Applications under Transcranial Direct Current Stimulation. in BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings., 8919120, BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings, Institute of Electrical and Electronics Engineers Inc., 2019 IEEE Biomedical Circuits and Systems Conference, BioCAS 2019, Nara, Japan, 17/10/19. https://doi.org/10.1109/BIOCAS.2019.8919120

A 2.36μW/Ch CMOS 8-Channel EEG Acquisition Unit with Input Protection Circuits for Applications under Transcranial Direct Current Stimulation. / Wu, Chung-Yu; Huang, Chi Wei; Tsai, Tzung Lin.

BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings. Institute of Electrical and Electronics Engineers Inc., 2019. 8919120 (BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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N2 - 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.

AB - 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.

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KW - HD-TDCS

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KW - low noise

KW - switched-capacitor

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BT - BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings

PB - Institute of Electrical and Electronics Engineers Inc.

Y2 - 17 October 2019 through 19 October 2019

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Wu C-Y, Huang CW, Tsai TL. A 2.36μW/Ch CMOS 8-Channel EEG Acquisition Unit with Input Protection Circuits for Applications under Transcranial Direct Current Stimulation. In BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings. Institute of Electrical and Electronics Engineers Inc. 2019. 8919120. (BioCAS 2019 - Biomedical Circuits and Systems Conference, Proceedings). https://doi.org/10.1109/BIOCAS.2019.8919120