| 摘要 |
A method for evaluating a capacitance of a sensor electrode of a proximity sensor includes charging the electrode with a charge voltage. Simultaneously, a compensation capacitance is charged by coupling the compensation capacitance between a reference voltage and ground. The sensor electrode and the compensation capacitance are decoupled from voltage sources and a state of charge of the sensor electrode and of the compensation capacitance is maintained. The sensor electrode is coupled to the compensation capacitance and the charges are balanced; then decoupled from the compensation capacitance and the charge is maintained. The compensation capacitance is then coupled to an evaluation network. The charge of a hold capacitance in the evaluation network is reversed by a charge-reversal current which is dependent on the current flow of the compensation capacitance. The charge of the hold capacitance is evaluated after one or more such cycles. |
