Low Power and Accurate Current Driver IC for Electrical Impedance Tomography Applications

Abstract

In this paper, a current driver targeting for Electrical Impedance Tomography is proposed. The proposed IC is designed based on active electrode configuration. First, high output impedance current driver is implemented with phase compensation scheme through a delay-locked loop (DLL) to significantly alleviate a phase shift and a required power consumption in the driver. Second, low-power pseudo-sine wave generator is used not only for a low-harmonic distortion but also for a flexible injection frequency utilization. Third, the calibration unit is proposed to compensate injection-current amplitude variations among active electrodes. As a results, the proposed current driver IC guarantees more than 1 MO output impedance over a wide range of injection current up to 400 mu A and operating frequency from 1 kHz to 5 MHz, only consuming 2.79 mW.