Paper Info
Title
A −68 dB THD, 0.6 mm 2 Active Area Biosignal Acquisition System With a 40–320 Hz Duty-Cycle Controlled Filter
Abstract
This paper presents a reconfigurable front-end (FE) circuit for acquiring various low-frequency biomedical signals. An energy and area-efficient tunable filter is proposed for adapting the FE bandwidth to the signal of interest. The filter is designed using a switched-R-MOSFET-C (SRMC) technique to realize the needed ultra-low cutoff frequency. An 8-bit SAR ADC, following the filter, quantizes the signal, while the SAR control logic is re-used to accurately program the filter bandwidth from 40 Hz to 320 Hz with a 40 Hz step. The prototype chip includes the complete FE system, formed of an instrumentation amplifier (IA), a programmable-gain amplifier (PGA), and the proposed tunable filter followed by the SAR ADC. Implemented in 0.13 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS technology, the IC occupies a 0.6 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> active area while consuming 6.3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> dc power from a 2-V supply. Measurement results show a FE gain range of 43–55 dB with an integrated input-referred noise ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V_{\text {IRN}}}$ </tex-math></inline-formula> ) of 3.45 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu V_{\text {rms}}$ </tex-math></inline-formula> , a 66 dB dynamic range (DR), and a total-harmonic distortion (THD) of −68 dB at an input amplitude of 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}V_{PP}$ </tex-math></inline-formula> . The effective number of bits (ENOB) for the ADC is 7.921 bits at 1-kS/s. In real-time Electrocardiogram (ECG), Electromyography (EMG), and Electroencephalography (EEG) measurements, high-fidelity waveforms are acquired using the proposed FE IC, validating the system’s reconfigurability and high-linearity.
Year
DOI
Venue
2020
10.1109/TCSI.2019.2943904
IEEE Transactions on Circuits and Systems I: Regular Papers
Keywords
DocType
Volume
Bandwidth,Iron,Clocks,Electromyography,Electroencephalography,Integrated circuits,Electrocardiography
Journal
67
Issue
ISSN
Citations 
1
1549-8328
0
PageRank 
References 
Authors
0.34
0
3
Name
Order
Citations
PageRank
Yu-Pin Hsu152.13
Zemin Liu26412.71
Mona Mostafa Hella36814.51