28.5 A 0.6V/0.9V 26.6-to-119.3µW ΔΣ-Based Bio-Impedance Readout IC with 101.9dB SNR and <0.1Hz 1/f Corner

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28.5 A 0.6V/0.9V 26.6-to-119.3µW ΔΣ-Based Bio-Impedance Readout IC with 101.9dB SNR and <0.1Hz 1/f Corner
Title:
28.5 A 0.6V/0.9V 26.6-to-119.3µW ΔΣ-Based Bio-Impedance Readout IC with 101.9dB SNR and <0.1Hz 1/f Corner
Journal Title:
2021 IEEE International Solid- State Circuits Conference (ISSCC)
Keywords:
Publication Date:
03 March 2021
Citation:
Zhang, T., Son, H., Gao, Y., Lan, J., & Heng, C.-H. (2021). 28.5 A 0.6V/0.9V 26.6-to-119.3µW ΔΣ-Based Bio-Impedance Readout IC with 101.9dB SNR and <0.1Hz 1/f Corner. 2021 IEEE International Solid- State Circuits Conference (ISSCC). https://doi.org/10.1109/isscc42613.2021.9365801
Abstract:
Bio-impedance (BioZ) is an important physiological parameter in wearable healthcare sensing. Besides the inherent cardiac and respiratory information, BioZ can be also used for other emerging applications such as non-invasive blood status sensing [1]. A conventional 4-electrode (4E) setup eliminates the effect of electrode-tissue impedance (ETI) at the expense of user comfort, system complexity, and cost. On the other hand, a 2-electrode (2E) setup avoids short-falls of 4E but can only capture relative changes of BioZ instead of its absolute value. In addition, a readout front-end (RFE) with wide dynamic range (DR) and high signal-to-noise ratio (SNR) is needed to deal with small BioZ variation (0.1~10Ω) as well as large baseline resistance (>10kΩ). A conventional RFE architecture employing an instrumentation amplifier (IA) and ADC has to trade-off between resolution, DR and noise [2,3]. Although flicker noise in the current generator (CG) is mitigated through dynamic element matching (DEM) [2], the reference current (IREF) noise issue remains unaddressed. In [5], digital-assisted baseline cancellation and IREF correlated noise cancellation are proposed, which help eliminate IREF noise and input-dependent noise [4] due to the large signal in the current-balance instrumentation amplifier (CBIA). Nevertheless, larger noise is still observed due to the finite residual current (I res ) from the baseline cancellation.
License type:
Publisher Copyright
Funding Info:
This research / project is supported by the A*STAR - Programmatic - Cyber-Physicalchemical Interfaces
Grant Reference no. : A18A1b0045
Description:
© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
ISBN:
978-1-7281-9549-0
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