Diehl Ako Stiftung & Co. Kg

Roland Müller

Werner Kaps

Harald Mangold

A circuit configuration for a capacitive touch switch contains at least one sensor circuit with a capacitive sensor element which changes its capacitance value when touched, and an evaluation circuit which is supplied with an output signal from the sensor circuit in order to determine whether the capacitive sensor element is actuated or not. The at least one sensor circuit has a capacitance which is connected in parallel with the capacitive sensor element, and a capacitance/frequency converter which is connected to the parallel circuit containing the capacitance and the capacitive sensor element and generates, at its output, a frequency signal whose frequency depends on the total capacitance of the parallel circuit containing the capacitance and the capacitive sensor element. The evaluation circuit may thus use a significant change in the frequency of the output signal from the sensor circuit to deduce, in a simple manner, that the capacitive sensor element has been touched.

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Opfenbach, Germany

Roland Müller