A battery-based constant current source (Bb-CCS) for biomedical applications

A constant current source is essential for impedance measurement techniques in several biomedical applications. The impedance measurement studies in biomedical applications such as bioelectrical impedance analysis (BIA), electrical impedance plethysmography (IPG), electrical impedance myography (EIM), electrical impedance cardiography (ICG), electrical impedance spectroscopy (EIS), electrical impedance tomography (EIT) all need a high precision impedance measurement circuit with high signal to noise ratio (SNR). Moreover the impedance measurement circuit applied to the biomedical, clinical or medical applications such as human subject studies should have a better patient safety. In this direction a Battery-based Constant Current Source (Bb-CCS) is developed for biomedical applications. The Bb-CCS is developed with a modified Howland current source (MHCS) fed by a battery based power supply (BBPS). The current amplitude, frequency and waveforms are set as the circuit variables which are found as adjustable as per the requirements. The frequency responses, load response, Fast Fourier Transform (FFT) of the Bb-CCS are studied and results show that the Bb-CCS can be suitably used for multifrequency impedance measurement methods in biomedical applications.