An 8MHz 31.25kS/s Impedance-Monitoring IC Based on IF-Sampling Architecture with a Band-Pass Delta-Sigma ADC

Kweon, Soon-Jae; Gil, José María Mengual; Park, Chulhyun; Oh, Saewoong; Jung, Yoontae; Choi, Injun; Cheon, Song-I; Dang, Hung Phan; Koo, Ja-Hyuck; Kim, Geunhoe; Ha, Sohmyung; Je, Minkyu

doi:10.23919/vlsicircuits52068.2021.9492406

Cited by 7 publications

(10 citation statements)

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“…The current injection is preferred to the direct voltage excitation in most biomedical applications to prevent any injection of unwanted high currents. When the target impedance is small as <1 kΩ [48], the simplest way, in which a waveform is generated by a current DAC and the current is injected directly to the target material, can be adopted without any current driver [48], [67]. In many cases, a separate current driver is needed because most waveform-generation and linearity-enhancement circuits are operated in the voltage domain.…”

Section: Discussionmentioning

confidence: 99%

“…For the generation of DAC-based sinusoids, direct digital synthesizers (DDSs) are widely used in on-chip EIS systems [35], [36], [39], [47], [48]. Fig.…”

Section: A Dac-based Sinusoidmentioning

confidence: 99%

Section: A Open-loop Current Driversmentioning

confidence: 99%

“…The simplest open-loop method of injecting a current to an impedance is to generate a waveform using a current DAC and inject the DAC's output current directly to the target impedance [48], [53]- [57], [65], [70]- [72], [74]- [80]. Many of such current DACs use the cascode current-source structures to have an high output impedance [48], [53]- [57], [70], [77]. Among them, there are two advanced current mirrors with higher output impedance than the typical cascode structures: a regulated cascode structure [71] and a triple cascode structure [74].…”

Section: A Open-loop Current Driversmentioning

confidence: 99%

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On-Chip Sinusoidal Signal Generators for Electrical Impedance Spectroscopy: Methodological Review

Kweon¹,

Rafi

Cheon

et al. 2022

IEEE Trans. Biomed. Circuits Syst.

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This paper reviews architectures and circuit implementations of on-chip sinusoidal signal generators (SSGs) for electrical impedance spectroscopy (EIS) applications. In recent years, there have been increasing interests in on-chip EIS systems, which measure a target material's impedance spectrum over a frequency range. The on-chip implementation allows EIS systems to have low power and small form factor, enabling various biomedical applications. One of the key building blocks of on-chip EIS systems is on-chip SSG, which determines the frequency range and the analysis precision of the whole EIS system. On-chip SSGs are generally required to have high linearity, wide frequency range, and high power and area efficiency. They are typically composed of three stages in general: waveform generation, linearity enhancement, and current injection. First, a sinusoidal waveform should be generated in SSGs. The generated waveform's frequency should be accurately adjustable over a wide range. The firstly generated waveform may not be perfectly linear, including unwanted harmonics. In the following linearity-enhancement step, these harmonics are attenuated by using filters typically. As the linearity of the waveform is improved, the precision of the EIS system gets ensured. Lastly, the filtered voltage waveform is now converted to a current by a current driver. Then, the current sinusoidal signal is injected into the target impedance. This review discusses the principles, advantages, and disadvantages of various techniques applied to each step in state-of-the-art on-chip SSGs. In addition, state-of-the-art designs are compared and summarized.

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Section: Discussionmentioning

confidence: 99%

“…For the generation of DAC-based sinusoids, direct digital synthesizers (DDSs) are widely used in on-chip EIS systems [35], [36], [39], [47], [48]. Fig.…”

Section: A Dac-based Sinusoidmentioning

confidence: 99%

Section: A Open-loop Current Driversmentioning

confidence: 99%

Section: A Open-loop Current Driversmentioning

confidence: 99%

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On-Chip Sinusoidal Signal Generators for Electrical Impedance Spectroscopy: Methodological Review

Kweon¹,

Rafi

Cheon

et al. 2022

IEEE Trans. Biomed. Circuits Syst.

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“…The low-IF architecture, shown in Fig. 2.d [27], demodulates the input signal to IF, and digitizes directly at IF with a continuous time (CT) bandpass (BP) ∆Σ ADC to avoid 1/f noise and DC offset. Moreover, since it employs I/Q demodulation in digital domain, it can flexibly trade-off data throughput and impedance sensitivity as required for the application.…”

Section: Introductionmentioning

confidence: 99%

A Bioimpedance Spectroscopy Interface for EIM Based on IF-Sampling and Pseudo 2-Path SC Bandpass ΔΣ ADC

Fernandez 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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A Low-Distortion Current-Mode Signal Generator for Wide-Range Bioimpedance Spectroscopy

Schrunder,

Rusu

2023

2023 IEEE International Symposium on Circuits and Systems (ISCAS)

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This paper presents a low-distortion current-mode sinusoidal signal generator for bioimpedance spectroscopy measurements. The proposed full current-mode operation enables linearity enhancement and potential savings in silicon area and power consumption. Programmability in the low-pass filter and current driver enables impedance measurements from 0.2 Ω to 10 kΩ over a wide frequency range from 1 kHz to 1 MHz. The current generator, designed in a 0.18 µm CMOS process, consumes between 736 µW at the lowest frequency and gain, and 1.70 mW at the highest frequency and gain, and occupies 1.76 mm 2 silicon area. Post-layout simulation results show a spuriousfree dynamic range larger than 40 dBc over the entire frequency range, which enables bioimpedance measurements with errors below 1%, as it is required for wearable devices evaluating neuromuscular disorders.

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An 8MHz 31.25kS/s Impedance-Monitoring IC Based on IF-Sampling Architecture with a Band-Pass Delta-Sigma ADC

Cited by 7 publications

References 0 publications

On-Chip Sinusoidal Signal Generators for Electrical Impedance Spectroscopy: Methodological Review

On-Chip Sinusoidal Signal Generators for Electrical Impedance Spectroscopy: Methodological Review

A Bioimpedance Spectroscopy Interface for EIM Based on IF-Sampling and Pseudo 2-Path SC Bandpass ΔΣ ADC

A Low-Distortion Current-Mode Signal Generator for Wide-Range Bioimpedance Spectroscopy

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