A Polar-Demodulation-Based Impedance-Measurement IC Using Frequency-Shift Technique With Low Power Consumption and Wide Frequency Range

Cheon, Song-I; Kweon, Soon-Jae; Kim, Young–In; Koo, Jimin; Ha, Sohmyung; Je, Minkyu

doi:10.1109/tbcas.2021.3135836

Cited by 7 publications

(13 citation statements)

References 32 publications

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“…Polar demodulation is a promising alternative which asynchronously measures the magnitude and phase of the bioimpedance [ 29 , 30 , 31 , 32 , 33 , 34 ], as shown in Figure 4 . It is a tetra-polar measurement technique based on determining the magnitude and the phase of a complex impedance, Z X , by extracting and processing two voltage signals, V AZ and V AS , obtained as a response to a sinusoidal excitation current, I ex .…”

Section: Methodsmentioning

confidence: 99%

Wearable and Noninvasive Device for Integral Congestive Heart Failure Management in the IoMT Paradigm

Ausin

Ramos²,

Lorido³

et al. 2023

Sensors

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Noninvasive remote monitoring of hemodynamic variables is essential in optimizing treatment opportunities and predicting rehospitalization in patients with congestive heart failure. The objective of this study is to develop a wearable bioimpedance-based device, which can provide continuous measurement of cardiac output and stroke volume, as well as other physiological parameters for a greater prognosis and prevention of congestive heart failure. The bioimpedance system, which is based on a robust and cost-effective measuring principle, was implemented in a CMOS application specific integrated circuit, and operates as the analog front-end of the device, which has been provided with a radio-frequency section for wireless communication. The operating parameters of the proposed wearable device are remotely configured through a graphical user interface to measure the magnitude and the phase of complex impedances over a bandwidth of 1 kHz to 1 MHz. As a result of this study, a cardiac activity monitor was implemented, and its accuracy was evaluated in 33 patients with different heart diseases, ages, and genders. The proposed device was compared with a well-established technique such as Doppler echocardiography, and the results showed that the two instruments are clinically equivalent.

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Section: Methodsmentioning

confidence: 99%

Wearable and Noninvasive Device for Integral Congestive Heart Failure Management in the IoMT Paradigm

Ausin

Ramos²,

Lorido³

et al. 2023

Sensors

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show abstract

“…Without knowing the injected current exactly, accuracy of the impedance measurement cannot be ensured. By adding a reference resistor in series with the target impedance and measure the voltage across the resistor, the actual current that flows through the target impedance can be known for more accurate impedance measurements [30], [110]. However, this technique requires more circuits and power for measuring the voltage across the reference resistor.…”

Section: Current Driversmentioning

confidence: 99%

“…Fig. 2(a) shows a general block diagram of widely used onchip EIS systems based on the single-tone stimulus method [28]- [30]. A sinusoidal signal generator (SSG) injects a sinusoidal current signal into the target material, and a demodulator extracts the real and imaginary parts of the target impedance by quadrature mixing with the in-phase and quadrature-phase (90 • -shifted) signals.…”

Section: Introductionmentioning

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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“…Alternatively, a low-pass filter (LPF) can be used to reduce power consumption and avoid design complexity [38]. It creates a DC value by averaging the signal φ p (t) regardless of the frequency.…”

Section: Introductionmentioning

confidence: 99%

An Impedance Readout IC with Ratio-Based Measurement Techniques for Electrical Impedance Spectroscopy

Cheon

Kweon

Kim

et al. 2022

Sensors

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This paper presents an error-tolerant and power-efficient impedance measurement scheme for bioimpedance acquisition. The proposed architecture measures the magnitude and the real part of the target complex impedance, unlike other impedance measurement architectures measuring either the real/imaginary components or the magnitude and phase. The phase information of the target impedance is obtained by using the ratio between the magnitude and the real components. This can allow for avoiding direct phase measurements, which require fast, power-hungry circuit blocks. A reference resistor is connected in series with the target impedance to compensate for the errors caused by the delay in the sinusoidal signal generator and the amplifier at the front. Moreover, an additional magnitude measurement path is connected to the reference resistor to cancel out the nonlinearity of the proposed system and enhance the settling speed of the low-pass filter by a ratio-based detection. Thanks to this ratio-based detection, the accuracy is enhanced by 30%, and the settling time is improved by 87.7% compared to the conventional single-path detection. The proposed integrated circuit consumes only 513 μW for a wide frequency range of 10 Hz to 1 MHz, with the maximum magnitude and phase errors of 0.3% and 2.1°, respectively.

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A Polar-Demodulation-Based Impedance-Measurement IC Using Frequency-Shift Technique With Low Power Consumption and Wide Frequency Range

Cited by 7 publications

References 32 publications

Wearable and Noninvasive Device for Integral Congestive Heart Failure Management in the IoMT Paradigm

Wearable and Noninvasive Device for Integral Congestive Heart Failure Management in the IoMT Paradigm

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

An Impedance Readout IC with Ratio-Based Measurement Techniques for Electrical Impedance Spectroscopy

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