Method for bidirectional transferring of charge between measuring and charging capacitors in capacitive proximity sensor of motor vehicle, involves discharging capacitors that exhibit larger capacitance than measuring capacitor

摘要

The method involves delivering a large voltage pulse to a control port (2) via a triggering unit (AE). A coupling network (AN) comprising screening capacitors (C26) is arranged between a measuring capacitor (Cx) or a test electrode (EL). A small voltage is delivered to the control port. The capacitors are discharged after a selector switching element (S2) reaches a switching position, where the capacitors exhibit larger capacitance than the measuring capacitor such that a part of a charge from the measuring capacitor arrives at the charging capacitor and not at the capacitors. The small voltage pulse is a zero magnitude voltage pulse. Independent claims are also included for the following: (1) an electronic selector switch controlled pulse charge transfer device (2) a capacitive proximity sensor (3) a motor vehicle.