Method for setting a scanning frequency of a capacitive touch-sensitive switch, operating method for a capacitive touch-sensitive switch and capacitive touch-sensitive switch

1. A method for adjusting a scanning frequency of a capacitive touch-sensitive switch having a capacitive sensor element and a sensor circuit, the method comprising:

operating the touch-sensitive switch by using a first measurement method and at a scanning frequency having been selected from a group of available scanning frequencies;

detecting measurement signals of the sensor circuit, and carrying out the detection of the measurement signals by including a step of generating an amplitude/time graph;

checking whether the detected measurement signals contain or could contain a critical alias effect, and carrying out the check as to whether the detected measurement signals contain or could contain a critical alias effect by including a step of converting the generated amplitude/time graph into an amplitude/frequency graph and checking whether the amplitude/frequency graph contains a peak;

setting the scanning frequency as a selection frequency for a detection operating mode of the touch-sensitive switch when no critical alias effect and no possibility of a critical alias effect are identified during the check; and

not setting the scanning frequency as the selection frequency when no peak is identified during the check as to whether the amplitude/frequency graph contains a peak.

2. The method according to claim 1 , which further comprises:

repeating the operation of the touch-sensitive switch, the detection of the measurement signals of the sensor circuit and the checking of the measurement signals, for a plurality of different scanning frequencies; and

setting one of the plurality of scanning frequencies during the checking of the measurement signals of which neither a critical alias effect nor a possibility of a critical alias effect is identified, as the selection frequency.

3. A capacitive touch-sensitive switch, comprising:

a capacitive sensor element;

a sensor circuit connected to said capacitive sensor element; and

a control unit connected to said sensor circuit for driving said sensor circuit, said control unit configured to execute the operating method according to claim 2 .

4. The method according to claim 1 , which further comprises, when no critical alias effect and no possibility of a critical alias effect are identified in each case during the checking of the measurement signals of a plurality of scanning frequencies, setting a scanning frequency of the plurality of scanning frequencies being best suited as the selection frequency, as the selection frequency.

5. The method according to claim 1 , which further comprises selecting the first measurement method from a measurement method having a charge-charge cycle or a discharge-discharge cycle.

6. An operating method for a capacitive touch-sensitive switch, the method comprising:

adjusting a scanning frequency of the capacitive touch-sensitive switch according to claim 1 ; and

operating the capacitive touch-sensitive switch at the adjusted scanning frequency for detecting a switch actuation.

7. The operating method according to claim 6 , which further comprises performing the adjustment of the scanning frequency of the capacitive touch-sensitive switch in an initialization procedure at least one of when the capacitive touch-sensitive switch is first brought into operation or periodically during the operation of the capacitive touch-sensitive switch.

8. The operating method according to claim 7 , which further comprises performing the operation of the touch-sensitive switch for detecting a switch actuation by using a second measurement method differing from the first measurement method.

9. The operating method according to claim 8 , which further comprises selecting the second measurement method from a measurement method having a charge-discharge cycle or a discharge-charge cycle.

10. The operating method according to claim 6 , which further comprises performing the operation of the touch-sensitive switch for detecting a switch actuation by using a second measurement method differing from the first measurement method.

11. The operating method according to claim 10 , which further comprises selecting the second measurement method from a measurement method having a charge-discharge cycle or a discharge-charge cycle.

12. A capacitive touch-sensitive switch, comprising:

a capacitive sensor element;

a sensor circuit connected to said capacitive sensor element; and

a control unit connected to said sensor circuit for driving said sensor circuit, said control unit configured to execute the method for adjusting the scanning frequency of the capacitive touch-sensitive switch according to claim 1 .

13. A method for adjusting a scanning frequency of a capacitive touch-sensitive switch having a capacitive sensor element and a sensor circuit, the method comprising:

operating the touch-sensitive switch by using a first measurement method and at a scanning frequency having been selected from a group of available scanning frequencies;

detecting measurement signals of the sensor circuit;

checking whether the detected measurement signals contain or could contain a critical alias effect;

when an alias effect is identified during the check as to whether the detected measurement signals contain or could contain a critical alias effect, carrying out a check as to whether the identified alias effect would be critical in the detection operating mode of the touch-sensitive switch;

setting the scanning frequency as a selection frequency for a detection operating mode of the touch-sensitive switch when no critical alias effect and no possibility of a critical alias effect are identified during the check; and

not setting the scanning frequency as the selection frequency when no peak is identified during the check as to whether an amplitude/frequency graph contains a peak.

14. The method according to claim 13 , which further comprises carrying out the check as to whether the identified alias effect would be critical in the detection operating mode of the touch-sensitive switch by including a step of comparing a frequency at which the peak in the amplitude/frequency graph is identified with a threshold value.

15. A method for adjusting a scanning frequency of a capacitive touch-sensitive switch having a capacitive sensor element and a sensor circuit, the method comprising:

operating the touch-sensitive switch by using a first measurement method and at a scanning frequency having been selected from a group of available scanning frequencies;

detecting measurement signals of the sensor circuit, and carrying out the detection of the measurement signals by including a step of generating an amplitude/time graph;

checking whether the detected measurement signals contain or could contain a critical alias effect, and carrying out the check as to whether the detected measurement signals contain or could contain a critical alias effect by including a step of converting the generated amplitude/time graph into an amplitude/frequency graph and checking whether the amplitude/frequency graph contains a peak;

carrying out the check as to whether an identified alias effect would be critical in the detection operating mode of the touch-sensitive switch by including a step of comparing a frequency at which the peak in the amplitude/frequency graph is identified with a threshold value;

setting the scanning frequency as a selection frequency for a detection operating mode of the touch-sensitive switch when no critical alias effect and no possibility of a critical alias effect are identified during the check; and

not setting the scanning frequency as the selection frequency when no peak is identified during the check as to whether the amplitude/frequency graph contains a peak.