Development of an integrated volatile organic compounds microsensor for the IoT

The opportune scenario of the internet of things (IoT) provides new perspectives for the gas sensing industry. With these, come new challenges where resistive gas sensors, embedded inside a system on a chip, must be decoded with a short response time and low power consumption. This work aims to design a resistance-to-digital converter following those requirements. Two different types of resistance-to-digital converters are explored, the time-domain and the voltage-domain implementation. The final layout chosen is based on a-time domain approach. Using a relaxation oscillator topology, a RCO is designed and when coupled with a micro-controller, it is used as a gas sensor interface, meeting the IoT specifications.