Sensirion Ag

Harry Figi

Mark Hornung

Andreas Rüegg

Robert Wüest

Lucas Huber

Robert Wuest

A thermal sensor comprises an active element (), e.g., a heater or cooler, at least one temperature sensor (), and processing circuitry (). The processing circuitry causes a change of power supplied to the active element (). It then determines, at a plurality of times, a thermal parameter based on an output signal of the temperature sensors and analyzes the transient behavior of the thermal parameter. Based on this analysis, the processing circuitry determines a contamination signal that is indicative of a contamination on a sensing surface of the thermal sensor. If the thermal sensor comprises a plurality of temperature sensors arranged in different sectors of the sensing surface, a multi-sector thermal signal can be derived from the outputs of the sensors, and determination of the contamination signal can be based on the multi-sector thermal signal.

Detection of contaminations on a sensing surface of a thermal sensor

A flow sensor arrangement for determining the flow of a fluid comprises a substrate. A heater is arranged in or on the substrate as well as at least one first thermocouple for generating a first signal proportional to a temperature difference between a location downstream from the heater and a first reference location, and at least one second thermocouple for generating a second signal proportional to a temperature difference between a location upstream from the heater and a second reference location which second reference location is different from the first reference location. In addition, at least one third thermocouple is arranged in or on the substrate for generating a third signal proportional to a temperature difference between the first reference location and the second reference location. Means are provided for determining a sensing signal indicative of the flow of the fluid over the heater and the first and the second thermocouple dependent on the first signal, the second signal and the third signal.

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Stafa, Switzerland

Harry Figi