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AssigneeHuf Huelsbeck & Fuerst GmbH & Co. KG
InventorBerthold Sieg
Estimating the term…
A method for evaluating a capacitance of a sensor electrode of a proximity sensor includes charging the electrode with a charge voltage. Simultaneously, a compensation capacitance is charged by coupling the compensation capacitance between a reference voltage and ground. The sensor electrode and the compensation capacitance are decoupled from voltage sources and a state of charge of the sensor electrode and of the compensation capacitance is maintained. The sensor electrode is coupled to the compensation capacitance and the charges are balanced; then decoupled from the compensation capacitance and the charge is maintained. The compensation capacitance is then coupled to an evaluation network. The charge of a hold capacitance in the evaluation network is reversed by a charge-reversal current which is dependent on the current flow of the compensation capacitance. The charge of the hold capacitance is evaluated after one or more such cycles.
A method for evaluating the capacitance of a sensor electrode of a proximity sensor, having the steps:
A sensor device for detecting proximities, having a capacitive sensor electrode, wherein a sensor electrode switch device is provided, and the sensor electrode is coupled to the sensor electrode switch device, wherein a charge voltage source is coupled to the sensor electrode switch device, wherein a compensation capacitor is formed, which is coupled to at least one compensation capacitor switch device, wherein a reference voltage source is coupled to the compensation capacitor switch device, wherein the compensation capacitor switch device can be activated to either couple the compensation capacitor to the reference voltage source and ground in order to charge the compensation capacitor, or to decouple the compensation capacitor from the reference voltage source, in order to maintain the charge, wherein an evaluation network is formed, which can be coupled to the compensation capacitor via an evaluation network switch device, wherein the evaluation network has at least one support capacitor, wherein the sensor electrode switch device can be activated in order to couple the sensor electrode to at least the charge voltage source and, alternatively, to the compensation capacitor.
Dependencies are inferred from the claim text.