Active electrode IC combining EEG, electrical impedance tomography, continuous contact impedance measurement and power supply on a single wire

The IC presented integrates the front-end for EEG and Electrical Impedance Tomography acquisition on the electrode, together with contact impedance monitoring, so as to improve signal quality and functional integration of the two techniques for brain imaging applications. Only 4 wires connect the electrode to the back-end. The readout circuit consumes 1 mW, while the input referred noise for EEG signal acquisition is 0.45 μV_RMS between 0.5 and 100 Hz, doubling when both EEG and EIT are acquired simultaneously.