Characteristics of the Howland current source for bioelectric impedance measurements systems

Yazdanian, Hassan; Mosayebi-Samani, Mohsen; Mahanm, Amin

doi:10.1109/icbme.2013.6782216

Cited by 14 publications

(4 citation statements)

References 10 publications

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“…This expression matches that of the well-known Howland current source (Yazdanian et al, 2013;Mahnam et al, 2016) but the circuit in Figure 5 presents high input impedances and can be built with the ABB.…”

Section: Voltage To Current Converterssupporting

confidence: 53%

An analog building block for signal conditioning instrumentation circuits

Haberman¹,

Spinelli²

2021

IJIT

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The design of analogue signal conditioning circuits for instrumentation applications often requires designing a specific circuit for each case. For board-level design solutions, these circuits are generally implemented by using operational amplifiers (OA) and instrumentation amplifiers (IA). An analogue building block (ABB) is proposed, which can be implemented with three standard OAs. Using different connection schemes and just adding a few resistors, it allows implementing several analogue circuits such as common-mode conditioners, single-ended to differential and differential to single-ended converters, voltage and current amplifiers, current to voltage and voltage to current converters, among others. The proposed ABB is analysed and applied to several typical analogue conditioning problems. The design equations and experimental results for these circuits are presented.

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Section: Voltage To Current Converterssupporting

confidence: 53%

An analog building block for signal conditioning instrumentation circuits

Haberman¹,

Spinelli²

2021

IJIT

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“…The measurement of the radial artery pulse using bioimpedance and the process of PWV assessment are depicted in Figure 1. To begin, a current pump is utilized to inject a constant sinusoidal current into the wrist, independent of the resistance value of the targeted area [20,21]. This current injection is performed through two electrodes located on the distal and proximal ends, which serve as the injection points for the differential signal.…”

Section: Measurement Setup For Radial Artery Pulse Using Bioimpedancementioning

confidence: 99%

Arterial Pulse Wave Velocity Signal Reconstruction Using Low Sampling Rates

Hong,

Coté

2024

Biosensors

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Pulse Wave Velocity (PWV) analysis is valuable for assessing arterial stiffness and cardiovascular health and potentially for estimating blood pressure cufflessly. However, conventional PWV analysis from two transducers spaced closely poses challenges in data management, battery life, and developing the device for continuous real-time applications together along an artery, which typically need data to be recorded at high sampling rates. Specifically, although a pulse signal consists of low-frequency components when used for applications such as determining heart rate, the pulse transit time for transducers near each other along an artery takes place in the millisecond range, typically needing a high sampling rate. To overcome this issue, in this study, we present a novel approach that leverages the Nyquist–Shannon sampling theorem and reconstruction techniques for signals produced by bioimpedance transducers closely spaced along a radial artery. Specifically, we recorded bioimpedance artery pulse signals at a low sampling rate, reducing the data size and subsequently algorithmically reconstructing these signals at a higher sampling rate. We were able to retain vital transit time information and achieved enhanced precision that is comparable to the traditional high-rate sampling method. Our research demonstrates the viability of the algorithmic method for enabling PWV analysis from low-sampling-rate data, overcoming the constraints of conventional approaches. This technique has the potential to contribute to the development of cardiovascular health monitoring and diagnosis using closely spaced wearable devices for real-time and low-resource PWV assessment, enhancing patient care and cardiovascular disease management.

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“…In the development of ERT system, it is important to have a stable current source with broad bandwidth and high output impedance. Howland current source (HCS) circuit is a well known high performance, voltage controlled current source (VCCS) which capable to provide high output impedance as well as high frequency bandwidth [7]. The HCS consists of an operational amplifier (op-amp) and several resistors.…”

Section: Ert Front-end Circuitmentioning

confidence: 99%

Front-End Circuit in Electrical Resistance Tomography (ERT) for Two-Phase Liquid and Gas Imaging

Yunus

Rahim

et al. 2014

Jurnal Teknologi

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A steady and precise Voltage Control Current Source (VCCS ) with broad bandwidth plays a very important role in the quality of final images for the Electrical Resistance Tomography (ERT) system. Therefore, a model of current source is proposed in the paper which implement advanced Howland current pump as VCCS. The model are simulated through a software named multisim, and the simulation results show the proposed high-speed operational amplifier (op-amp) LM7171 is capable to produce constant output current at 10 mA (peak) when the frequency changes between 1 kHz to 500 kHz with load varies from 10 Ω to 1 kΩ. A two-dimensional (2D) simulation was performed using COMSOL and the results showed that the model is capable to detect air bubble (radius=10 mm) in a two-phase liquid and gas. The result presented with opposite excitation method with 150 kHz current at 10 mA. The measurement of boundary potentials are significantly influenced by bubble positions particularly towards the boundary. They are hoped to provide useful approaches for the design of practical and low-cost VCCS in ERT system.

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Characteristics of the Howland current source for bioelectric impedance measurements systems

Cited by 14 publications

References 10 publications

An analog building block for signal conditioning instrumentation circuits

An analog building block for signal conditioning instrumentation circuits

Arterial Pulse Wave Velocity Signal Reconstruction Using Low Sampling Rates

Front-End Circuit in Electrical Resistance Tomography (ERT) for Two-Phase Liquid and Gas Imaging

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