Ifm Electronic Gmbh

Jörg Schulz

Capacitive door handle sensor comprising at least one transmission electrode and a reception electrode, an operational amplifier configured as a charge amplifier and connected to the reception electrode, a switch for charge transfer, a first and a second switch for discharging the two operational amplifier inputs and, a capacitor arranged between the output and the inverting input of the operational amplifier, and a control unit for controlling and evaluating the measurement, wherein the control unit comprises a reference potential switching output which is connected to a terminal of the switch and is configured to selectively control a capacitance measurement between the transmission electrodes and the reception electrode or between the reception electrode and ground. Furthermore, methods for setting different operating modes are claimed.

Capacitive sensor for the automotive sector with a charge amplifier

An evaluation circuit for a capacitive sensor for detecting the distance, speed, or position of an object, comprises a reference capacitance and a measuring capacitance. A square wave voltage is applied to the reference capacitance and the measuring capacitance via a resistor, and a pulse which has a variable duration is obtained with the aid of a logic linking unit. The reference capacitance is connected to a first switching stage and the measuring capacitance is connected to a further switching stage. A single measuring capacitance has a capacitive coupling to an auxiliary electrode, and the switching stages are part of a logic linking unit. An output of the logic linking unit is connected to an integration stage. A charging capacitor (Ca) is charged or discharged via an output of the integration stage.

Evaluation circuit for a capacitive sensor, capacitive sensor, and actuator in a motor vehicle

The disclosure relates to a method for operating a pulse generator for generating measuring pulses for a capacitive sensor having an adjustable pulse time in the range from 10 ns to 200 ns, having a controllable delay circuit which contains a first integrating RC combination (RTCT) and a second integrating RC combination (RTCT), having a logical combining element having two inputs and one output, an initialization circuit and a control unit, wherein the first input of the logical combining element receives a clock signal, and the second input of the logical combining element receives an analog setting signal (SSE) from the output of the delay circuit, wherein two simultaneous clock signals are generated, of which the first clock signal (T) is led without delay to the first input of the logical combining element, and the second clock signal (T), delayed by the delay circuit, is led to the second input of the logical combining element, time-variable output pulses are generated with the aid of time-variable preloading signals (VL), wherein the output from the delay circuit after each measuring pulse is discharged or charged by the initialization switch.

Method for operating a pulse generator for capacitive sensors, and pulse generator

The present invention provides an electronic circuit for controlling an actuator comprising a transceiver unit () for a bus system the bus terminal () of which has a monostable behavior with an active period of greater than 1 ms, wherein the transceiver unit () is controlled by a microcontroller (), wherein the monostable behavior of the transceiver unit () is switched off with additionally superimposed control pulses, wherein the time interval between two control pulses is smaller than the monostable active period of the transceiver unit () and the control pulses are generated by temporal combination of two control signals the time resolution of which is lower than the pulse duration of the control pulses derived therefrom, which is implemented by use of a RC combination () and/or a logic gate () with a differentiating or delaying effect.

Electronic circuit for controlling an actuator

The present invention relates to an 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 wherein by use of a logic unit a time variable pulse is obtained the duration of which is a measure for the respective measuring capacitance.

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, speed, or position of an object, having a reference capacitance and two measuring capacitances, wherein a square-wave voltage is applied to the reference capacitance and the measuring capacitances via a resistor and a pulse which has a variable period and represents a measure of the particular measuring capacitance is obtained with the aid of a switching stage.

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Tettnang, Germany

Jörg Schulz