A Fully Integrated Gas Detection System With Programmable Heating Voltage and Digital Output Rate for Gas Sensor Array

In this paper, a gas detection system for 2 x 2 MEMS gas sensor array is proposed. It has multiple measurement channels, programmable heating voltage, programmable measurement time, 24-bit digital output with 8-bit accuracy, wide measurement range and high linearity. The chip is realized in SMIC 180 nm complementary metal oxide semiconductor technology with an area of 1.58 mm x 1.66 mm. The result of the fixed resistance measurement shows that the linearity of the resistance ranges (200 Ω-200 KΩ, 200 Ω -500 KΩ,200 Ω-1 MΩ, 200 Ω-2 MΩ, 200 Ω-5MΩ, and 200 Ω-10MΩ) are all less than 1% at different measurement time intervals. At 1 s measurement time, the circuit has a wide detectable resistance range (200 Ω -10 MΩ), and high linearity of 0.3047%. The experimental results combined with the resistive MEMS gas sensor array show that the circuit has a good detection effect in the gas concentration range (0 ppm-340 ppm), and can even detect the change of gas concentration at a low concentration of 0.1 ppm. Moreover, the system can detect different responses of the same sensor at different heating voltages.