Simulation of a current source with a cole-cole load for multi-frequency electrical impedance tomography

Author

Santos, Susana Aguiar ; Schlebusch, Thomas ; Leonhardt, Steffen

Author_Institution

Med. Inf. Technol., RWTH Aachen Univ., Aachen, Germany

fYear

2013

fDate

3-7 July 2013

Firstpage

6445

Lastpage

6448

Abstract

An accurate current source is one of the keys in the hardware of Electrical impedance Tomography systems. Limitations appear mainly at higher frequencies and for non-simple resistive loads. In this paper, we simulate an improved Howland current source with a Cole-Cole load. Simulations comparing two different op-amps (THS4021 and OPA843) were performed at 1 kHz to 1 MHz. Results show that the THS4021 performed better than the OPA843. The current source with THS4021 reaches an output impedance of 20 MΩ at 1 kHz and above 320 kΩ at 1 MHz, it provides a constant and stable output current up to 4 mA, in the complete range of frequencies, and for Cole-Cole (resistive and capacitive) load.

Keywords

bioelectric phenomena; biomedical electronics; constant current sources; electric impedance imaging; electric impedance measurement; Howland current source simulation; OPA843 op-amps; THS4021 op-amps; capacitive load; cole-cole load; frequency 1 kHz to 1 MHz; hardware; multifrequency electrical impedance tomography system; resistive load; Capacitance; Current measurement; Hardware; Impedance; Integrated circuit modeling; Load modeling; Tomography; Cole-Cole model; Electrical Impedance Tomography (EIT); Improved Howland current source;

fLanguage

English

Publisher

ieee

Conference_Titel

Engineering in Medicine and Biology Society (EMBC), 2013 35th Annual International Conference of the IEEE

Conference_Location

Osaka

ISSN

1557-170X

Type

conf

DOI

10.1109/EMBC.2013.6611030

Filename

6611030