Temperature-regulated gas sensor with gas selective filter

The invention is directed to a gas sensor that includes a hotplate, a support structure, a gas selective filter, and circuitry. The support structure is configured to define a cavity. The gas selective filter is held by the support structure and spans the cavity. Various components are connected to the circuitry, and may include a temperature sensor element, a gas sensing element, and a heater. The temperature sensor element is configured to sense a temperature Tf of the filter. The gas sensing element is sensitive to a target gas in the cavity. The heater is in thermal communication with the gas sensing element. The circuitry is configured to operate the sensing element, estimate a temperature Tf of the filter, and regulate the heater. The circuitry regulates an extent to which power is supplied to the heater based on the estimated temperature Tf of the filter.