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US 2017/0254674 A1Published application
Capacitive Sensor, The Associated Evaluation Circuit And Actuator For A Motor Vehicle
AssigneeIfm Electronic GmbH
InventorJörg Schulz
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AssigneeIfm Electronic GmbH
InventorJörg Schulz
Estimating the term…
The invention relates to a capacitive sensor, the associated evaluation circuit and an actuator for a motor vehicle having the above-mentioned sensor for detecting the distance, the speed or the position of an object, having a reference capacitance 1 and two measuring capacitances 2, wherein a square-wave voltage 3 is applied to the reference capacitance 1 and the measuring capacitances 2 via a resistor and a pulse 7 which has a variable period and represents a measure of the particular measuring capacitance 2 is obtained with the aid of a switching stage 4, wherein the reference capacitance 1 is connected to the input of a first switching stage 41 and the measuring capacitances 2 are connected to the inputs of further switching stages 42, 43, wherein the switching stages 42, 43 have enable inputs which are controlled by the output of the first switching stage 41, wherein the outputs of the switching stages 42, 43 are each connected to the input of one of the integration stages 5, wherein a charging capacitor 8 is charged via the outputs of the integration stages 5, wherein a starting signal is generated when the threshold voltage of a first switching stage 41 is reached and a stop signal is generated when the threshold voltage of a second switching stage 42, 43 is reached.
Evaluation circuit for a capacitive sensor for detecting the distance, speed or position of an object, comprising a reference capacitance and two measuring capacitances, wherein the reference capacitance and the measuring capacitances are supplied with a square wave voltage via a resistor, and with the aid of a switching stage a time variable pulse is obtained which is a measure for the respective measuring capacitance,
Capacitive sensor comprising an evaluation circuit for detecting the distance, speed or position of an object, comprising a reference capacitance and two measuring capacitances, wherein the reference capacitance and the measuring capacitances are supplied with a square wave voltage via a resistor, and with the aid of a switching stage a time variable pulse is obtained which is a measure for the respective measuring capacitance,
Actuator in a motor vehicle comprising a capacitive sensor comprising an evaluation circuit for detecting the distance, speed or position of an object, comprising a reference capacitance and two measuring capacitances, wherein the reference capacitance and the measuring capacitances are supplied with a square wave voltage via a resistor, and with the aid of a switching stage a time variable pulse is obtained which is a measure for the respective measuring capacitance, characterized in that the reference capacitance is connected to the input of a first switching stage and the measuring capacitances are connected to the inputs of further switching stages, wherein the further switching stages include enable inputs which are triggered by the output of the first switching stage, wherein the outputs of the further switching stages are respectively connected to the input of the integration stages, wherein a charging capacitor is charged via the outputs of the integration stages, wherein upon reaching the threshold voltage of a first switching stage a start signal and upon reaching the threshold voltage of a second switching stage a stop signal is generated.
Dependencies are inferred from the claim text.