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 SoC is integrated into belt-type EIT system with 32 electrodes and can show the dynamic images of the lung ventilation on the mobile devices. It has 3 key building blocks; 1) a T-switch for high off isolation > 60 dB between electrodes, 2) a I/Q signal generation and demodulation for high fidelity image, and 3) an on-chip fast demodulation scheme to reduce scanning time and ADC speed. As a result, real and imaginary part of images can be reconstructed with 97.3% of accuracy and can be displayed on the mobile devices. 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.