Comparison of Howland and General Impedance Converter (GIC) circuit based current sources for bio-impedance measurements

Qureshi, Tabassum-Ur-Razaq, Chatwin, Chris, Huber, Nicolas, Zarafshani, Ali, Tunstall, Benjamin and Wang, Wei (2010) Comparison of Howland and General Impedance Converter (GIC) circuit based current sources for bio-impedance measurements. Journal of Physics: Conference Series, 224 (1). 012167. ISSN 1742-6588

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Abstract

The current source is a key component in bio-impedance measurement systems. The accuracy of the current source can be measured in terms of its output impedance together with other parameters, with certain applications demanding extremely high output impedance. This paper presents an investigation and comparison of different current source designs based on the Enhanced Howland circuit combined with a General Impedance Converter (GIC) circuit using both ideal and non-ideal operational amplifiers. Under differing load conditions two different settings of the GIC are evaluated and the results are compared to show its performance settings. Whilst the study has shown that over a wide bandwidth (i.e. 100Hz-100MHz) the output impedance is limited, operation over a more limited range offers output impedance in the Giga-ohm range, which can be considered as being infinite.

Item Type: Article
Keywords: Bioimpedance measurement; Current sources; General impedance converters; High output; Key component; Load condition; Output impedance; Wide bandwidth
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Subjects: Q Science > QA Mathematics
Q Science > QA Mathematics > QA0075 Electronic computers. Computer science
R Medicine > R Medicine (General) > R856 Biomedical engineering. Electronics. Instrumentation
T Technology
T Technology > TK Electrical engineering. Electronics Nuclear engineering
T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7800 Electronics
Depositing User: Chris Chatwin
Date Deposited: 30 Aug 2012 09:10
Last Modified: 07 Mar 2017 08:57
URI: http://sro.sussex.ac.uk/id/eprint/40504

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