Low power current sources for bioimpedance measurements: a comparison between Howland and OTA-based CMOS circuits

Bertemes-Filho, Pedro; Vincence, V. C.; Santos, Márcio Silveira dos; Zanatta, Ilson Xavier

doi:10.5617/jeb.380

Cited by 22 publications

(14 citation statements)

References 48 publications

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“…The allowable injected current amplitude must comply with international safety standards [ 17 ]. As a result, the current source requires large output impedance in high-frequency broadband, and output current ensures low distortion and meets low-power requirements for acupuncture point skin impedance measurements which is limited in existing integrated current source [ 18 – 22 ]. For current source design studies, most have used the Howland topology circuit architecture, which is designed with discrete electronic component connections [ 22 – 25 ].…”

Section: Introductionmentioning

confidence: 99%

“…As a result, the current source requires large output impedance in high-frequency broadband, and output current ensures low distortion and meets low-power requirements for acupuncture point skin impedance measurements which is limited in existing integrated current source [ 18 – 22 ]. For current source design studies, most have used the Howland topology circuit architecture, which is designed with discrete electronic component connections [ 22 – 25 ]. Current source design [ 24 ] uses a Howland topology to achieve a high output impedance (1.7 MΩ at 50 kHz) for the current source by using a resistor with a precision tolerance of 0.01%.…”

Section: Introductionmentioning

confidence: 99%

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A Low-Power Stable Wideband Current Source for Acupuncture Point Skin Impedance Measurements

Qiu

Zhao

et al. 2021

Journal of Healthcare Engineering

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A low-power stable wideband current source for acupuncture point skin impedance measurements has been designed employing a differential architecture and negative feedback. The circuits extend bandwidth to 1 MHz, reducing harmonic distortion to 0.24% at 1 MHz. The output impedance is 37 MΩ at 100 kHz and 11 MΩ at 1 MHz. The stability of the output current of the current source when connected to different loads is below 0.1% at frequencies up to 500 kHz and increases to 0.74% at 1 MHz. The circuit was manufactured in a 0.13-μm CMOS technology and measured results are presented. The area of the current source is 0.09 mm2 and its consumption is 1.2 mW. It is intended for low-power acupuncture point skin impedance measurements.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Low-Power Stable Wideband Current Source for Acupuncture Point Skin Impedance Measurements

Qiu

Zhao

et al. 2021

Journal of Healthcare Engineering

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“…The proposed measurement system ( Figure 4 ), which was an implementation of a Howland Pump circuit ( Figure 3 ) was a voltage controlled current source and, by driving its input with varying frequency voltage waveforms generated by a Tektronix AFG3021 function generator, the resulting current waveforms were applied to the samples. This circuit topology was implemented in applications that required a steady current at a wide frequency bandwidth for bioimpedance measurements [ 45 , 46 , 47 ]. Output current was adjusted with V REF and R 1 applying a voltage to pin V REF and selecting a resistor value (R 1 ) ( Figure 3 ).…”

Section: Methodsmentioning

confidence: 99%

Evaluation of Cancer Cell Lines by Four-Point Probe Technique, by Impedance Measurements in Various Frequencies

et al. 2021

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Cell-based biosensors appear to be an attractive tool for the rapid, simple, and cheap monitoring of chemotherapy effects at a very early stage. In this study, electrochemical measurements using a four-point probe method were evaluated for suspensions of four cancer cell lines of different tissue origins: SK–N–SH, HeLa, MCF-7 and MDA-MB-231, all for two different population densities: 50 K and 100 K cells/500 μL. The anticancer agent doxorubicin was applied for each cell type in order to investigate whether the proposed technique was able to determine specific differences in cell responses before and after drug treatment. The proposed methodology can offer valuable insight into the frequency-dependent bioelectrical responses of various cellular systems using a low frequency range and without necessitating lengthy cell culture treatment. The further development of this biosensor assembly with the integration of specially designed cell/electronic interfaces can lead to novel diagnostic biosensors and therapeutic bioelectronics.

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“…The voltage-mode approach is characterized by the current generation through the voltage in one or more of the active circuit's nodes. Such topologies include the well-known Howland current pump (HCP) [14][15][16][17][18][19], the Tietze topology [20], the load-in-the-loop topology [21], and differential-difference topologies [22][23][24]. Current-mode approach makes use of operational transconductance amplifiers (OTAs) [7,11,25,26] or current conveyors (CCII) [15,27,28] for the current excitation.…”

Section: Introductionmentioning

confidence: 99%

Analysis, Simulation, and Development of a Low-Cost Fully Active-Electrode Bioimpedance Measurement Module

Dimas¹,

Alimisis²,

Georgakopoulos³

et al. 2021

Technologies

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A low-cost 1 kHz–400 kHz operating frequency fully-active electrode bioimpedance measurement module, based on Howland current source, is presented in this paper. It includes a buffered positive feedback Howland current source, implemented with operational amplifiers, as well as an AD8421 instrumentation amplifier, for the differential voltage measurements. Each active electrode module can be connected to others, assembling a wearable active electrode module array. From this array, 2 electrodes can be selected to be driven from a THS413 fully differential amplifier, activating a mirrored Howland current source. This work performs a complete circuit analysis, verified with MATLAB and SPICE simulations of the current source’s transconductance and output impedance over the frequency range between 1 kHz and 1 MHz. Resistors’ tolerances, possible mismatches, and the operational amplifiers’ non-idealities are considered in both the analysis and simulations. A comparison study between four selected operational amplifiers (ADA4622, OPA2210, AD8034, and AD8672) is additionally performed. The module is also hardware-implemented and tested in the lab for all four operational amplifiers and the transconductance is measured for load resistors of 150 Ω, 660 Ω, and 1200 Ω. Measurements showed that, using the AD8034 operational amplifier, the current source’s transconductance remains constant for frequencies up to 400 KHz for a 150 Ω load and 250 kHz for a 1200 Ω load, while lower performance is achieved with the other 3 operational amplifiers. Finally, transient simulations and measurements are performed at the AD8421 output for bipolar measurements on the 3 aforementioned load resistor values.

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Low power current sources for bioimpedance measurements: a comparison between Howland and OTA-based CMOS circuits

Cited by 22 publications

References 48 publications

A Low-Power Stable Wideband Current Source for Acupuncture Point Skin Impedance Measurements

A Low-Power Stable Wideband Current Source for Acupuncture Point Skin Impedance Measurements

Evaluation of Cancer Cell Lines by Four-Point Probe Technique, by Impedance Measurements in Various Frequencies

Analysis, Simulation, and Development of a Low-Cost Fully Active-Electrode Bioimpedance Measurement Module

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