A 10.4 mW Electrical Impedance Tomography SoC for Portable Real-Time Lung Ventilation Monitoring System

An electrical impedance tomography (EIT) SoC is proposed for the portable real-time lung ventilation monitoring system. The proposed EIT SoC is integrated into belt-typefabric system with 32 electrodes and can show the dynamic images of the lung ventilation on the mobile devices. To get high fidelity images, a T-switch is adopted for high off-isolation between electrodes more than 60 dB, and I/Q signal generation and demodulation can obtain both real and imaginary part of images. For the real-time imaging, an on-chip fast demodulation scheme is proposed, and it can also reduce speed requirements of ADC for low-power consumption. The proposed EIT SoC of 5.0 mm × 5.0 mm is fabricated in 0.18 μm CMOS technology, and consumes only 10.4 mW with 1.8 V supply. As a result, EIT images were reconstructed with 97.3% of accuracy and up to 20 frames/s real-time lung images can be displayed on the mobile devices.