Patent · US Active

Circuit configuration for a capacitive touch switch

US7375656B2 · kind B2 · utility

19Cited by

4References

12Claims

0Family size

Assignee

Diehl AKO Stiftung & Co. KG · DE

Inventors

Roland Muller · Weiling, DE
Harald Mangold · Lippach, DE
Werner Kaps · Weiler-Simmerberg, DE

Key dates

Filing date	Dec 19, 2005
Grant date	May 20, 2008
Priority date	—
Expiry date	Jul 8, 2026

Classification

Technology area (CPC H)Electricity
CPC primaryH03K2217/960715
WIPO fieldBasic communication processes
WIPO sectorElectrical engineering

Abstract

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.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.