Li, J;
Jiang, D;
Wu, Y;
Demosthenous, A;
(2025)
A 30MHz Wideband 92.7dB SNR 99.6% Accuracy Bioimpedance Spectroscopy IC Using Time-to-Digital Demodulation with Co-Prime Delay Locked Sampling.
In:
Digest of Technical Papers - IEEE International Solid-State Circuits Conference.
(pp. pp. 572-574).
IEEE: San Francisco, CA, USA.
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Abstract
The permittivity and conductivity of bioimpedance in tissues are governed by α, β, and y dispersions, with biological features detectable in the tens of MHz range. Wideband spectroscopy is required in many applications including body fluid volume assessment [1], cancer diagnosis [2], anatomical characterization [3], and plant content estimation [4]. However, state-of-the-art bioimpedance ICs are limited to frequencies up to 10MHz, which hampers biological research. For example, estimating starch content in cassavas requires wideband spectroscopy with frequencies up to 30MHz [4]. In a wideband system using analog I-Q demodulation, accuracy is limited by the large distortion from its multiplication process; a phase error of 4.32° at 10MHz was reported in [2]. In a wideband system using digital I-Q demodulation, a phase error of 0.15% at 10MHz was reported in [5] but at the expense of a large power consumption (12.2mW for the amplifier and ADC alone) and a mediocre SNR of 65dB. This paper presents a wideband (30MHz) bioimpedance spectroscopy IC achieving both high SNR (92.7dB) and high accuracy (99.6%) with low power consumption (3.18mW). The IC employs time-to-digital (T-D) demodulation and features: 1) a co-prime delay-locked (CDL) sampling approach achieving an equivalent sampling rate of 21.6GHz with a 240MHz sampling clock; 2) a delay-locked loop (DLL) architecture utilizing a compact phase comparator for high accuracy delay generation; 3) optimized wideband design for the current generator and readout front end to further reduce power consumption. The IC has 0.39% magnitude error and 0.57° phase error at 30MHz bioimpedance spectroscopy measurements.
| Type: | Proceedings paper |
|---|---|
| Title: | A 30MHz Wideband 92.7dB SNR 99.6% Accuracy Bioimpedance Spectroscopy IC Using Time-to-Digital Demodulation with Co-Prime Delay Locked Sampling |
| Event: | 2025 IEEE International Solid-State Circuits Conference (ISSCC) |
| Dates: | 16 Feb 2025 - 20 Feb 2025 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1109/ISSCC49661.2025.10904781 |
| Publisher version: | https://doi.org/10.1109/isscc49661.2025.10904781 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10208573 |
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