A Bio-Impedance Readout IC With Digital-Assisted Baseline Cancellation for Two-Electrode Measurement

Ha, Hyunsoo; Sijbers, Wim; Wegberg, Roland van; Xu, Jiawei; Konijnenburg, Mario; Vis, Peter; Breeschoten, Arjan; Song, Shunfeng; Hoof, Chris Van; Helleputte, Nick Van

doi:10.1109/jssc.2019.2939077

Cited by 48 publications

(36 citation statements)

References 19 publications

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“…It can be seen that the performance of the dedicated bio-signal acquisition ASIC is relatively good. Since the reconfigurable architecture presented in this article has a current balanced IA (CBIA) architecture, it can fundamentally achieve the previously announced CBIA voltage noise level [7,19,20]. An appropriate paper to compare with the ideas pursued in this article is IMEC Xu's 2018 paper.…”

Section: Fabrication and Measurement Resultsmentioning

confidence: 99%

Simultaneous Voltage and Current Measurement Instrumentation Amplifier for ECG and PPG Monitoring

Kim

2021

Electronics

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An instrumentation amplifier (IA) capable of sensing both voltage and current at the same time has been introduced and applied to electrocardiogram (ECG) and photoplethysmogram (PPG) measurements for cardiovascular health monitoring applications. The proposed IA can switch between the voltage and current sensing configurations in a time–division manner faster than the ECG and PPG bandwidths. The application-specific integrated circuit (ASIC) of the proposed circuit design was implemented using 180 nm CMOS fabrication technology. Input-referred voltage noise and current noise were measured as 3.9 µVrms and 172 pArms, respectively, and power consumption was measured as 34.9 µA. In the current sensing configuration, a current noise reduction technique is applied, which was confirmed to be a 25 times improvement over the previous version. Using a single IA, ECG and PPG can be monitored in the form of separated ECG and PPG signals. In addition, for the first time, a merged ECG/PPG signal is acquired, which has features of both ECG and PPG peaks.

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Section: Fabrication and Measurement Resultsmentioning

confidence: 99%

Simultaneous Voltage and Current Measurement Instrumentation Amplifier for ECG and PPG Monitoring

Kim

2021

Electronics

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“…This is because the center frequency of the BPF is controlled by the frequency of an external clock, rather than g m of the transconductors, therefore ω 0 can be precisely controlled over process, voltage, and temperature (PVT) variations. A chopper-based mixer with a sequentially varying clock frequency and a subsequent LPF stage was used in [59] where its operational principle is similar to that of lock-in amplifiers, also commonly used in bio-impedance sensors [52], [70]. This architecture achieved a 60 nW ultra-low-power consumption, however, because it sequentially demodulates over the desired frequency band, it cannot perform the filtering operation over its entire frequency range at once.…”

Section: Discussionmentioning

confidence: 99%

Continuous-Time Analog Filters for Audio Edge Intelligence: Review and Analysis on Design Techniques

Kim¹,

Liu²

2022

Preprint

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Silicon cochlea designs capture the functionality of the biological cochlea. Their use has been explored for cochlea prosthesis applications and more recently in edge audio devices which are required to support always-on operation. As their stringent power constraints pose several design challenges, IC designers are forced to look for solutions that use low standby power. One promising bio-inspired approach is to combine the continuous-time analog filter channels of the silicon cochlea with a small memory footprint deep neural network that is trained on edge tasks such as keyword spotting, thereby allowing all blocks to be embedded in an IC. This paper reviews the analog filter circuits used as feature extractors for current edge audio devices, starting with the original biquad filter circuits proposed for the silicon cochlea. Our analysis starts from the interpretation of a basic biquad filter as a two-integrator-loop topology and reviews the progression in the design of second-order low-pass and band-pass filters ranging from OTA-based to source-followerbased architectures. We also derive and analyze the small-signal transfer function and discuss performance aspects of these filters. The analysis of these different filter configurations can be applied to other application domains such as biomedical devices which employ a front-end bandpass filter.

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“…The output of SRO is divided coarsely by N times using D Flip-Flop (D-FF) and the C REF of FLL circuit is fine controlled through proper sizing. The complete transfer function H BPF (s) of the proposed time-domain BPF is given in (5). Its center frequency ω 0 and Q-factor are given in (6) where the Q-factor is designed as 2 for each BPF channel by proper sizing of the switching transistors in the SROs.…”

Section: B Time-domain Band-pass Filtermentioning

confidence: 99%

“…However, most of them traded off between power and latency. In [3], a 142 nW VAD IC using sequential mixer-based FEx was proposed where the operational principle is similar to that used for bio-impedance sensors [4], [5]. However, this sequential frequency scanning is too undersampled for the KWS and results in a 512 ms latency for VAD.…”

Section: Introductionmentioning

confidence: 99%

A 23-μW Keyword Spotting IC With Ring-Oscillator-Based Time-Domain Feature Extraction

Kim

Gao²,

Graça³

et al. 2022

IEEE J. Solid-State Circuits

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This article presents the first keyword spotting (KWS) IC which uses a ring-oscillator-based time-domain processing technique for its analog feature extractor (FEx). Its extensive usage of time-encoding schemes allows the analog audio signal to be processed in a fully time-domain manner except for the voltage-to-time conversion stage of the analog front-end. Benefiting from fundamental building blocks based on digital logic gates, it offers a better technology scalability compared to conventional voltage-domain designs. Fabricated in a 65 nm CMOS process, the prototyped KWS IC occupies 2.03mm 2 and dissipates 23 µW power consumption including analog FEx and digital neural network classifier. The 16-channel time-domain FEx achieves 54.89 dB dynamic range for 16 ms frame shift size while consuming 9.3 µW. The measurement result verifies that the proposed IC performs a 12-class KWS task on the Google Speech Command Dataset (GSCD) with >86% accuracy and 12.4 ms latency.

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A Bio-Impedance Readout IC With Digital-Assisted Baseline Cancellation for Two-Electrode Measurement

Cited by 48 publications

References 19 publications

Simultaneous Voltage and Current Measurement Instrumentation Amplifier for ECG and PPG Monitoring

Simultaneous Voltage and Current Measurement Instrumentation Amplifier for ECG and PPG Monitoring

Continuous-Time Analog Filters for Audio Edge Intelligence: Review and Analysis on Design Techniques

A 23-μW Keyword Spotting IC With Ring-Oscillator-Based Time-Domain Feature Extraction

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