Circuit for operating a capacitive sensor and sensor apparatus

A sensor apparatus, comprising:

• a capacitive sensor which is configured to be operated alternately over a first time interval in a first mode, over a second time interval in a second mode, and over a third time interval in a third mode;
• and
• a circuit configured to operate the capacitive sensor, the circuit including:
• a GM stage configured to receive a sensor voltage applied to a sensor output of the capacitive sensor and to output a current, and
• an integrator configured to integrate the output current over a time course and to output an output voltage resulting therefrom,
• wherein the circuit is configured to provide the output voltage to an analog-to-digital converter,
• wherein the circuit is configured to provide the output voltage to the capacitive sensor as a feedback voltage in the first mode and in the second mode,
• wherein the circuit is configured to perform, in the first mode, an offset correction in the GM stage and the integrator,
• wherein the circuit is configured to switch the sensor output of the capacitive sensor to high impedance in the second mode, and
• wherein the circuit is configured to provide a reference voltage to the capacitive sensor in the third mode.