A novel NDIR gas sensing technique based on delta-sigma architecture

This work describes the implementation and the modeling of a gas sensor with delta-sigma architecture. Beyond the conventional technique of periodic heating of light source, our proposed delta-sigma architecture with closed-loop system is obtained by the hybrid combination of a CO₂ (Carbon dioxide) infrared sensor prototype which includes an amplifier, FPGA and discrete electronic devices. After a modeling of system, we derive the relationship between gas concentration and sensor by the heating and cooling times. The measurement results show a practical application for all the NDIR measuring techniques and this work also gives a new approach not only to measure gas concentration fast but also obtain the high resolution.