An Active Electrode Readout Circuit

  • Jiawei Xu
  • Refet Firat Yazicioglu
  • Chris Van Hoof
  • Kofi Makinwa
Chapter
Part of the Analog Circuits and Signal Processing book series (ACSP)

Abstract

This chapter presents an AE with gain, which results in a better noise-power tradeoff than a buffer-based AE. The proposed AE utilizes an instrumentation amplifier (IA) with state-of-the-art performance, making it suitable for dry-electrode EEG acquisition. The IA is based on an AC-coupled chopper amplifier, equipped with impedance boosting and digitally-assisted offset trimming. These techniques improve the IA’s input impedance and reduce its intrinsic offset, respectively. Mismatch between two AEs is usually a dominant contributor of a low CMRR. As shown in this chapter, the mismatch problem is addressed by a back-end common-mode feedback (CMFB) circuit, leading to a 30 dB improvement of CMRR. In addition, the AE-based EEG readout circuit is benchmarked with a reference EEG system to demonstrate the AE’s benefits, namely, reduced sensitivity to cable motion artifacts and mains interference.

Keywords

CMFB Impedance boosting DC servo Chopper amplifier 

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Copyright information

© Springer International Publishing AG 2018

Authors and Affiliations

  • Jiawei Xu
    • 1
  • Refet Firat Yazicioglu
    • 2
  • Chris Van Hoof
    • 3
  • Kofi Makinwa
    • 4
  1. 1.Holst Centre / imecEindhovenThe Netherlands
  2. 2.Galvani BioelectronicsStevenageUK
  3. 3.ESAT-MICASKU Leuven / imecLeuvenBelgium
  4. 4.Delft University of TechnologyDelftThe Netherlands

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