A phase-domain readout circuit for a CMOS-compatible thermal-conductivity-based carbon dioxide sensor

The measurement of carbon-dioxide (CO2) concentration is very important in home and building automation, e.g. to control ventilation in energy-efficient buildings. This application requires compact, low-cost sensors that can measure CO₂ concentration with a resolution of <200 ppm over a 2500ppm range. Conventional optical (NDIR...