Conference Paper

A 28-μW EEG readout front-end utilizing a current-mode instrumentation amplifier and a source-follower-based LPF

Dept. of Biomed. Eng., Univ. of Macau, Macau, China
DOI: 10.1109/PRIMEASIA.2010.5604878 Conference: Microelectronics and Electronics (PrimeAsia), 2010 Asia Pacific Conference on Postgraduate Research in
Source: IEEE Xplore


A novel low-power EEG readout front-end featuring a current-mode instrumentation amplifier (CMIA) followed by a 4th-order gain-compensated source-follower-based lowpass filter (LPF) is proposed. The CMIA is of current-conveyor topology and is chopper-stabilized to improve the common-mode noise rejection and suppress the dc-offset and 1/f noise. The typical gain-loss problem of source-follower-based LPF is alleviated by adopting a gain-compensation technique. Optimized in 0.35-μm CMOS, the achieved CMRR is >100 dB from 0.01 to 16 Hz, and >90 dB up to 40 Hz. With the chopper stabilization, the noise voltage density is 248 nV√Hz at 0.01 Hz and 197 nV√Hz at 100 Hz. The power consumption is 28 μW at 3 V.

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    • "Most of present clinical treatments require the patients, who are under a long-time continuous monitoring, to be connected by many signal acquisition devices. This may cause inconvenience to the subject and it will affect the original EEG signal characteristics (Corrigan et al., 2000; Zhang et al., 2000). The realisation of portable wearable devices for external bio potential recording is fundamental issue to monitor human without restricting their mobility. "
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    ABSTRACT: Electroencephalogram (EEG) plays a vital role in several medical diagnosis (brain tumour detection, Alzheimer disease, epilepsy, etc.), engineering applications (emotion detection, drowsiness detection, stress assessment, etc.) and others. However, the cost of the EEG device is usually high (< $20,000) and it is still a challenging issue for many consumers. The cost of the EEG data acquisition device is purely depends on number of EEG channels, mode of signal transmission (wired/wireless), data resolution, software portability, etc. In recent years, the development of handy embedded systems opens a gateway to design and develop the data acquisition devices at a cheaper cost. In this work, we have used SBC TS 7800 (500 MHz, 128 MB RAM) for designing the EEG wired data acquisition device. This embedded system is used to acquire the data from the 32 EEG channels and to save the them in American Standard Code for Information Interchange (ASCII) values in either .txt or xls format for further research investigations. All the EEG channels are made up of Ag/Ag-Cl and have an impedance of 10 kΩ. This complete system is operating in Linux platform, and programs are developed using C and JAVA programming languages.
    Full-text · Article · Jan 2013 · International Journal of Medical Engineering and Informatics
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    ABSTRACT: A novel ultra low power, area-efficient, current-mode instrumentation amplifier (CMIA) with embedded bandpass filter, for acquisition of bio-potential signals is presented. A novel bias front-end is also presented, which achieves CMRR of 195dB at 1Hz in the presence of ±5% component mismatch. The CMIA has a tunable bandwidth, from 160Hz to 7.2kHz with input referred rms noise of 2.24 μV in frequency band of 5mHz to 160Hz. The CMIA is designed in 180nm mixed-mode CMOS technology and provides rail to rail output voltage of 1.65V(p-p) while dissipating 39 μW, at 1.8V supply voltage. The output of CMIA doesn't need any further signal conditioning.
    No preview · Conference Paper · Jan 2013