A Microcontrolled Constant Current Source for Wideband Bioimpedance Measurements

Daniela Loi, Claudia Palla, Gianfranco Marongiu, Michele Gallamini, and Gianmarco Angius

Keywords

Multifrequency measurement, Constant current source, Bioelectrical impedance measurement

Abstract

We describe a programmable wide frequency bandwidth current source realized using a COTS-based (Commercial Off-the-Shelf) design. It is capable of injecting sinusoidal, square or triangle current waveforms of amplitude ranging from 12μApp to 1.2mApp and frequency up to 1MHz, into the human body through a pair of electrodes. The device is controlled by a graphic user-friendly interface, which allows users to monitor data transmission and acquisition as well as to set current injection parameters. In addition to current injection, the system is meant for sensing in real time the resulting response. The measured voltage drop across tissue impedance can be amplified with a programmable gain and converted into digital values with 10 bits of resolution before being transmitted to a PC through USB transmission for further processing.

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