A 160μW 8-Channel Active Electrode System for EEG Monitoring

Jiawei Xu, Refet Firat Yazicioglu, Bernard Grundlehner, Pieter Harpe, Kofi A.A. Makinwa, Chris Van Hoof

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140 Citations (Scopus)
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This paper presents an active electrode system for gel-free biopotential EEG signal acquisition. The system consists of front-end chopper amplifiers and a back-end common-mode feedback (CMFB) circuit. The front-end AC-coupled chopper amplifier employs input impedance boosting and digitally-assisted
offset trimming. The former increases the input impedance of the active electrode to 2 G at 1 Hz and the latter limits the chopping induced output ripple and residual offset to 2 mV and 20 mV respectively. Thanks to chopper stabilization, the active electrode achieves 0.8 μVrms (0.5-100 Hz) input referred noise. The use of a back-end CMFB circuit further improves the CMRR of the active electrode readout to 82 dB at 50 Hz. Both front-end and back-end
circuits are implemented in a 0.18 μm CMOS process and the total current consumption of an 8-channel readout system is 88 μA from 1.8 V supply. EEG measurements using the proposed active electrode system demonstrate its benefits compared to passive electrode systems, namely reduced sensitivity to cable motion artifacts and mains interference.
Original languageEnglish
Pages (from-to)555-567
Number of pages13
JournalIEEE Transactions on Biomedical Circuits and Systems
Issue number6
Publication statusPublished - 2011

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  • Elektrotechniek
  • Techniek


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