Circuit arrangement for detecting the capacitance or capacitance change of a capacitive circuit element or component

Circuit arrangement for detecting the capacitance or capacitance change of a capacitive circuit element or component, comprising:

• a voltage source,
• at least one charging switch and at least one recharging switch,
• a control device which controls the charging switch and the recharging switch and which contains a clock generator,
• a storage capacitor, and
• an evaluation circuit which is connected to the storage capacitor,
• wherein the voltage source is connectable to the electrode of the capacitive circuit element or component via the charging switch in a closed position of the charging switch,
• wherein the second electrode of the capacitive circuit element or component is connected or connectable to a terminal of the voltage source, which terminal is away from the charging switch, so that the capacitive circuit element or component is charged by the voltage source when the charging switch is closed,
• wherein an electrode of the storage capacitor is connected or connectable to the electrode of the capacitive circuit element or component which is connected to the charging switch, and the second electrode of the storage capacitor is connectable via the closed recharging switch to the second electrode of the capacitive circuit element or component so that the capacitive circuit element or component is discharged onto the storage capacitor or the charge stored in the capacitive circuit element or component is recharged into the storage capacitor when the charging switch is opened and the recharging switch is closed, and
• wherein the evaluation circuit is able to determine the capacitance or capacitance change of the capacitive circuit element or component from the voltage on the storage capacitor after a certain number of charging and recharging cycles,
• wherein a capacitive noise voltage compensation element is provided which has a noise voltage compensation electrode connected to the second electrode of the storage capacitor, a second noise voltage compensation electrode connected to the second electrode of the capacitive circuit element or component, and
• wherein the noise voltage compensation element is arranged to be influenced by LF noise voltage in the same way as the capacitive circuit element or component.