A capacitive sensor configured for connection between a heating element and a heating current supply comprises a common mode choke (CMC) for AC-decoupling the heating element from the heating current supply. The CMC comprises first and second inductively coupled windings, the first winding for connection between a first terminal of the heating current supply and a first terminal of the heating element and the second winding for connection between a second terminal of the heating element and a second terminal of the heating current supply. The capacitive sensor further comprises a control and evaluation circuit for injecting an AC signal into the heating element via a measurement node, measuring a voltage on and/or a current across the measurement node, and to derive an impedance between the heating element and a counter electrode from the measurement. The CMC comprises a third winding inductively coupled with the first and second windings, the third winding being operatively coupled with the measurement node.
Capacitive sensor configured for using heating element as antenna electrode
2018-11-20
Patent
Elektronische Ressource
Englisch
IPC: | G01D MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE , Anzeigen oder Aufzeichnen in Verbindung mit Messen allgemein / B60H ARRANGEMENTS OR ADAPTATIONS OF HEATING, COOLING, VENTILATING, OR OTHER AIR-TREATING DEVICES SPECIALLY FOR PASSENGER OR GOODS SPACES OF VEHICLES , Anordnung oder Einbau der Heizung, Kühlung, Lüftung oder anderer Luftbehandlungsvorrichtungen für die Fahrzeugräume für Reisende oder Fracht / B60N SEATS SPECIALLY ADAPTED FOR VEHICLES , Sitze besonders für Fahrzeuge ausgebildet / B60R Fahrzeuge, Fahrzeugausstattung oder Fahrzeugteile, soweit nicht anderweitig vorgesehen , VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR |
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