| 摘要 |
A circuit arrangement for determining the capacitance of at least two capacitive sensor elements (104a~104n), the capacitance of each of which changing depending on the state of activation of the respective element, said arrangement comprising: a charging power source (600) adapted to generate a charging voltage; an integration capacitor (300), wherein a first connection of the integration capacitor is coupled to the charging power source (600); a number of sensor circuits (100a~100n), wherein the number of sensor circuits (100a~100n) corresponds to the number of sensor elements (104a~104n) and wherein a sensor circuit (100a~100n) is assigned to each sensor element (104a~104n), wherein each sensor circuit (100a~100n) comprises: a controllable switching means (101), a charging diode (102) and a recharging diode (103), wherein the controllable switching means (101) and the charging diode (102) are connected in series between the charging power source (600) and a connection of the capacitive sensor element (104) and the recharging diode (103) is connected between the connection of the capacitive sensor element (104) and a second connection of the integration capacitor (300); a control unit (700) that is adapted to trigger the respective controllable switching means (101a~101n) of the sensor circuits (100a~100n) in such a way that only one of the switching means is closed, and the remaining switching means are open; and an evaluation circuit (500) connected to the second connection of the integration capacitor (300) and adapted such that said evaluation circuit evaluates a voltage in effect at the second connection of the integration capacitor (300) so as to determine the capacitance of the sensor element whose switching means is closed. |
