A CMOS Magnitude/Phase Measurement Chip for Impedance Spectroscopy

Kassanos, Panagiotis; Triantis, Iasonas F.; Demosthenous, Andreas

doi:10.1109/jsen.2013.2251628

Cited by 68 publications

(69 citation statements)

References 30 publications

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“…Currently, a variety of methods, including offset cancellation, fully balanced current conveyor, replicating current comparator and differential current conveyor have been used to maximize speed with minimal power consumption due to demand for sophisticated applications that require high-performance CMOS current comparators. Researchers have also attempted to develop CMOS current comparators suitable for biomedical applications by measuring the electrical impedance [34].…”

Section: Resultsmentioning

confidence: 99%

“…The CMOS current comparator presented in reference [34] was applied in biomedical applications to measure the EIS (electrical impedance spectroscopy). This measurement is carried out using a magnitude/phase measurement system consisting of a block combination of two IA (instrumentation amplifiers), two clock less comparators, phase detector, switch modulator and Gm-C Integrator.…”

Section: Clock Less Continuous-time Multistep Comparator In a Plethormentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of Low Power and High Speed CMOS Current Comparators

Rahman

Reaz²,

Marufuzzaman

et al. 2016

Transactions on Electrical and Electronic Materials

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Over the past few decades, CMOS current comparators have been used in a wide range of applications, including analogue circuits, MVL (multiple-valued logic) circuits, and various electronic products. A current comparator is generally used in an ADC (analog-to-digital) converter of sensors and similar devices, and several techniques and approaches have been implemented to design the current comparator to improve performance. To this end, this paper presents a bibliographical survey of recently-published research on different current comparator topologies for low-power and high-speed applications. Moreover, several aspects of the CMOS current comparator are discussed regarding the design implementation, parameters, and performance comparison in terms of the power dissipation and operational speed. This review will serve as a comparative study and reference for researchers working on CMOS current comparators in low-power and high-speed applications.

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Section: Resultsmentioning

confidence: 99%

Section: Clock Less Continuous-time Multistep Comparator In a Plethormentioning

confidence: 99%

Evaluation of Low Power and High Speed CMOS Current Comparators

Rahman

Reaz²,

Marufuzzaman

et al. 2016

Transactions on Electrical and Electronic Materials

View full text Add to dashboard Cite

show abstract

“…Various methods are used to extract the real and imaginary parts (i.e., the Cartesian coordinates) of the (complex) bio-impedance [9]. Another promising alternative method is measuring the magnitude and the phase (i.e., the polar coordinates) of the (complex) bio-impedance [10].…”

Section: Bio-impedance Measurementmentioning

confidence: 99%

Mixed-Signal IC With Pulse Width Modulation Wireless Telemetry for Implantable Cardiac Pacemakers in 0.18-μm CMOS

Rezaeiyan

Zamani

Shoaei

et al. 2018

IEEE Trans. Biomed. Circuits Syst.

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A low-power mixed-signal IC for implantable pacemakers is presented. The proposed system features three independent intracardiac signal readout channels with pulse-width-modulated outputs. Also, the proposed system is capable of measuring the amplitude and phase of the bioimpedance with pulse-width-modulated outputs for use in rate adaptive pacemakers. Moreover, a stimulation system is embedded, offering 16 different amplitudes from 1 to 7.8 V. A backscattering transmitter transfers the output signals outside the body with very little power consumption. The proposed low-power mixed-signal IC is fabricated in a 0.18-μm HV CMOS process and occupies 2.38 mm. The biopotential channels extract the heart signals with 9.2 effective number of bits and the bioimpedance channels measure the amplitude and phase of the heart impedance with 1.35 Ω accuracy. The complete IC consumes only 4.2 μA from a 1-V power supply.

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“…However, the demodulation speed is restricted by the highorder low-pass filters. In recent years, digital demodulators have been widely used, including the synchronous sampling method [11], the DFT, FFT [12]- [14] and quadrature methods [15]- [18], etc. The synchronous sampling method is low-cost but the demodulation speed is also restricted by the low sampling rate.…”

Section: Introductionmentioning

confidence: 99%

A Recursive Demodulator for Real-Time Measurement of Multiple Sinusoids

Sun

Cao

et al. 2018

IEEE Sensors J.

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Abstract-A fast demodulator for real-time measurement of the amplitudes and phases of multiple sinusoids is highly desired in many applications. When the sampling frequency is fixed, the number of samples needed for demodulation determines the time consumption and hence the demodulation speed. In this paper, a quadrature demodulation method is firstly presented, which requires that the samples cover exactly integer periods of the multi-frequency signal. Secondly, a new recursive demodulation method is proposed, which can not only overcome the limitation of the quadrature method, but also provide greater flexibility between accuracy and speed, i.e. either to obtain a higher speed at an expense of a lower accuracy, or vice versa. The proposed method can work with a sample series of any length as long as more than twice the number of sinusoids and generate demodulation results for all sinusoids simultaneously. Thirdly, a resource-saving and fast implementation of the recursive demodulator was proposed and constructed on a DSP/FPGA, which enables in-situ and on-line application of the recursive demodulator. Experiments were carried out to investigate the performance of the proposed demodulator, including relative error, standard deviation and their variations with the number of samples involved in the demodulation, and compare with other conventional methods.Index Terms-Recursive demodulator, Quadrature method, Demodulation speed, DSP/FPGA I. INTRODUCTION n the active measurement of various object parameters, an external excitation signal is applied on the target object through a sensor. By measuring the response signal that carries the information of the object's characteristic parameters, the parameters to be measured can be derived. Sinusoid is a kind of commonly used excitation signal. To quickly obtain the target parameters of the object under excitation of a series of given frequencies, multiple sinusoids of the given frequencies can be combined as an excitation signal so that the unknowns are measured simultaneously. Because the response sensor signal is also composed of multiple sinusoids with the same frequencies and the frequencies are pre-known, only the amplitudes and phases of the sinusoids need to be obtained. The active measurement is required in many industrial and biomedical applications, such as industrial process tomography [1]- [3], bio-impedance measurement [4]- [6], eddy current testing [7], [8] and built-in self-test [9], etc. Because the characteristic parameters of the target object are often rapidly changing, real-time and fast measurement of the amplitudes and phases of multiple sinusoids in the response sensor signal is highly desired in sensor data processing.The demodulation process can be implemented using an analog method [10], which consists of multiplexers and filters. However, the demodulation speed is restricted by the highorder low-pass filters. In recent years, digital demodulators have been widely used, including the synchronous sampling method [11], the DFT, FFT [12]- [14] and...

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A CMOS Magnitude/Phase Measurement Chip for Impedance Spectroscopy

Cited by 68 publications

References 30 publications

Evaluation of Low Power and High Speed CMOS Current Comparators

Evaluation of Low Power and High Speed CMOS Current Comparators

Mixed-Signal IC With Pulse Width Modulation Wireless Telemetry for Implantable Cardiac Pacemakers in 0.18-μm CMOS

A Recursive Demodulator for Real-Time Measurement of Multiple Sinusoids

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