Cmos-compatible dew point sensor device and method of determining a dew point

A method of determining a dew point, comprising:

• providing a capacitor comprising a plurality of capacitor elements each having a capacitance;
• for each of the capacitor elements determining an increase of its capacitance caused by a decrease of the temperature of the capacitor;
• and
• deriving the dew point from a temperature at which the increases of the capacitances or values corresponding to the increases of the capacitances exceed a predefined limit by
• generating a set of binary digits, each of the binary digits corresponding to one of the capacitor elements and indicating whether the capacitance of the capacitor element is within a predefined range,
• comparing such sets of binary digits generated at different temperatures and determining the number of capacitor elements for which the corresponding binary digits of the sets are different, and
• repeating the comparison for a sequence of such sets generated at decreasing temperatures until the increase of the numbers thus obtained exceeds a predefined limit.

A dew point sensor device, comprising:

• a semiconductor substrate;
• a Peltier element;
• a temperature sensor;
• a capacitor at a surface above the substrate, the temperature sensor and the capacitor being arranged so that the temperature of the capacitor can be measured by the temperature sensor;
• the capacitor comprising a plurality of capacitor elements each having a capacitance;
• the electronic circuit being configured for an individual determination of the capacitances;
• the electronic circuit being configured for a generation of a set of binary digits, each of the binary digits corresponding to one of the capacitor elements and indicating whether the capacitance of the capacitor element is within a predefined range;
• and
• the electronic circuit being configured for a comparison of the set of binary digits generated at a first temperature with the set of binary digits generated at a second temperature, and for a determination of the number of capacitor elements for which the corresponding binary digits are different at the first temperature and the second temperature.