A Baseline-Tracking Single-Channel I/Q Impedance Plethysmogram IC for Neckband-Based Blood Pressure and Cardiovascular Monitoring

Park, Chan Sam; Kim, Hyunjoong; Lee, Kwangmuk; Keum, Dae Sik; Jang, Dong Pyo; Kim, Jae Joon

doi:10.1109/jssc.2022.3221478

Cited by 9 publications

(17 citation statements)

References 28 publications

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“…The proposed bio-Z interface achieves the best SNR max and a FoM SNR comparable with the state of the art, at the cost of higher power consumption due to the wider input range. Although previous art report better FoM SNR [24], [25], [30], it is worth noting that this work achieves competitive performance while digitizing the signal with high resolution at IF, which comes with several benefits in terms of data throughput, design simplicity, and flexibility as discussed throughout this paper. Furthermore, it can also be seen that our proposed bio-Z interface achieves considerably higher SNR and FoM as compared to previous art employing a low-IF readout architecture and BP ∆Σ ADC [27].…”

Section: B Electrical Characterizationmentioning

confidence: 91%

“…2) Noise Budget: One of the biggest design challenges in bio-Z readouts is achieving a good noise-to-power efficiency, while avoiding saturation of the readout due to a large baseline impedance [26]. Previous works, focusing on 2-electrode bio-Z measurements, propose cancelling the large baseline impedance from the electrodes [24]- [26], [30]. However, in EIM, the baseline bio-Z contains information regarding tissue composition, so it should be measured together with the timevarying bio-Z (requiring an SNR > 100 dB).…”

Section: B Quadrature If-sampling Readoutmentioning

confidence: 99%

“…Nonetheless, the SNR is practically constant above 2.2 kΩ, making the proposed readout suitable for measuring large resistors with sub-Ω sensitivity. Compared to the state of the art [24], [25], [30], the proposed interface achieves a higher SNR max despite employing a larger R DEG in the TCA, as it withstands a wider input voltage range, and avoids additional noise from baselineimpedance-cancelling feedback.…”

Section: B Electrical Characterizationmentioning

confidence: 99%

“…Furthermore, the LPF in [23] introduces significant signal distortions which affect the bio-Z accuracy. In [24]- [26], considerably better power efficiency is achieved, by implementing I/Q demodulation in the analog domain with the zero-second-IF architecture shown in Fig. 2.c.…”

Section: Introductionmentioning

confidence: 99%

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A Bioimpedance Spectroscopy Interface for EIM Based on IF-Sampling and Pseudo 2-Path SC Bandpass $\Delta\Sigma$ ADC

Schrunder,

Huang,

Rodriguez

et al. 2024

IEEE Trans. Biomed. Circuits Syst.

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This paper presents a low-noise bioimpedance (bio-Z) spectroscopy interface for electrical impedance myography (EIM) over the 1 kHz to 2 MHz frequency range. The proposed interface employs a sinusoidal signal generator based on direct-digital-synthesis (DDS) to improve the accuracy of the bio-Z reading, and a quadrature low-intermediate frequency (IF) readout to achieve a good noise-to-power efficiency and the required data throughput to detect muscle contractions. The readout is able to measure baseline and time-varying bio-Z by employing robust and power-efficient low-gain IAs and sixthorder single-bit bandpass (BP) ∆Σ ADCs. The proposed bio-Z spectroscopy interface is implemented in a 180 nm CMOS process, consumes 344.3 -479.3 µW, and occupies 5.4 mm 2 area. Measurement results show 0.7 mΩ/ √ Hz sensitivity at 15.625 kHz, 105.8 dB SNR within 4 Hz bandwidth, and a 146.5 dB figureof-merit. Additionally, recording of EIM in time and frequency domain during contractions of the bicep brachii muscle demonstrates the potential of the proposed bio-Z interface for wearable EIM systems.

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Section: B Electrical Characterizationmentioning

confidence: 91%

Section: B Quadrature If-sampling Readoutmentioning

confidence: 99%

Section: B Electrical Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Bioimpedance Spectroscopy Interface for EIM Based on IF-Sampling and Pseudo 2-Path SC Bandpass $\Delta\Sigma$ ADC

Schrunder,

Huang,

Rodriguez

et al. 2024

IEEE Trans. Biomed. Circuits Syst.

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“…To achieve such a high dynamic range, baseline cancellation techniques are commonly employed [17]. These techniques often entail subtracting the calculated baseline value from the received signal at the amplifier [18]- [20], as depicted in the Fig. 1.…”

mentioning

confidence: 99%

Impedance-Readout Integrated Circuits for Electrical Impedance Spectroscopy: Methodological Review

Cheon,

Choi,

Kang

et al. 2024

IEEE Trans. Biomed. Circuits Syst.

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This review paper provides a comprehensive overview of impedance-readout integrated circuits (ICs) for electrical impedance spectroscopy (EIS) applications. The readout IC, a crucial component of on-chip EIS systems, significantly affects key performance metrics of the entire system, such as frequency range, power consumption, accuracy, detection range, and throughput. With the growing demand for portable, wearable, and implantable EIS systems in the Internet-of-Things (IoT) era, achieving high energy efficiency while maintaining a wide frequency range, high accuracy, wide dynamic range, and high throughput has become a focus of research. Furthermore, to enhance the miniaturization and convenience of EIS systems, many emerging systems utilize two-electrode or dry electrode configurations instead of the conventional four-electrode configuration with wet electrodes for impedance measurement. In response to these trends, various technologies have been developed to ensure reliable operations even at two-or dryelectrode interfaces. This paper reviews the principles, advantages, and disadvantages of techniques employed in state-ofthe-art impedance-readout ICs, aiming to achieve high energy efficiency, wide frequency range, high accuracy, wide dynamic range, low noise, high throughput, and/or high input impedance. The thorough review of these advancements will provide valuable insights into the future development of impedance-readout ICs and systems for IoT and biomedical applications.

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Advancing Electrical Impedance Spectroscopy (EIS): Low-power, High-accuracy, Wide-dynamic-range, and High-throughput Impedance Measurement Circuits and Architectures

Choi,

Cheon,

Kang

et al. 2024

Low-Cost Diagnostics

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This chapter offers an extensive introduction to readout circuit architectures designed to measure impedances across a frequency range in electrical impedance spectroscopy (EIS). The impedance readout circuit, an essential component of on-chip EIS systems, significantly affects key system performances, including precision and speed of measurements, noise, and power consumption. With an increasing demand for implantable, wearable, and portable EIS systems, researchers have been focusing on achieving higher energy efficiency while maintaining high precision and speed in measurements. Additionally, to improve the compactness and ease of use of EIS systems, various systems use two-electrode and dry-electrode setups rather than the conventional four- and wet-electrode configurations. Numerous innovative methods have been developed to provide reliable measurements using two- and dry-electrode interfaces. This chapter discusses advances in impedance-readout architectures and their pros and cons. These approaches are designed to achieve low power consumption, broad frequency and input ranges, high accuracy with low noise, rapid measurement times, and/or high input impedance. The in-depth analyses of each of these improvements for EIS systems will provide insights into the future progress of small-form-factor EIS systems for biomedical and Internet of Things (IoT) applications.

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A Baseline-Tracking Single-Channel I/Q Impedance Plethysmogram IC for Neckband-Based Blood Pressure and Cardiovascular Monitoring

Cited by 9 publications

References 28 publications

A Bioimpedance Spectroscopy Interface for EIM Based on IF-Sampling and Pseudo 2-Path SC Bandpass $\Delta\Sigma$ ADC

A Bioimpedance Spectroscopy Interface for EIM Based on IF-Sampling and Pseudo 2-Path SC Bandpass $\Delta\Sigma$ ADC

Impedance-Readout Integrated Circuits for Electrical Impedance Spectroscopy: Methodological Review

Advancing Electrical Impedance Spectroscopy (EIS): Low-power, High-accuracy, Wide-dynamic-range, and High-throughput Impedance Measurement Circuits and Architectures

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