Enhanced offset compensation technique for thermal conductivity sensing of a gas concentration sensor

Abstract

A gas concentration sensor configured to measure a gas concentration of a target gas includes a reference chamber configured to contain a reference gas; a measurement chamber configured to contain the target gas; and a measurement circuit, configurable in a calibration mode and an operational mode, including a resistive bridge circuit including a first resistive element arranged in the reference chamber and a second resistive element arranged in the measurement chamber. The resistive bridge circuit is configured to receive an input voltage and generate a measurement signal based on the input voltage. During the calibration mode, the input voltage has a first voltage value at which the resistive bridge circuit has a negligible sensitivity to thermal conductivity such that the measurement signal is representative of an offset. The measurement circuit is configured to, during the operational mode, subtract the offset from the measurement signal to generate a compensated measurement signal.