DE102019135103A1 - Capacitive sensor device and method for operating a capacitive sensor device - Google Patents

Abstract

The invention relates to a capacitive sensor device (100) for an operating device of a vehicle for detecting an approach and / or contact with a first electrically conductive sensor electrode (E1) for the capacitive detection of the presence of an input means in a detection area of the sensor device (100), a control and evaluation device (8) with a first connection contact (9, 9A), a first connection line (11, 11A), a first reference capacitance (CRef-1), a first electrical resistor (R1, R1A) and a first reference connection contact (15A ), wherein the first reference connection contact (15A) can optionally be acted upon with a first defined reference potential (VRef1) or a second defined reference potential (VRef2), and wherein the sensor device (100) furthermore has at least one first Schottky diode (D1) and the first sensor electrode (E1) in this way via the first Schottky diode (D1) to the first reference connection contact (15A) is connected or connectable that the first Schottky diode (D1) blocks when the first reference potential (VRef1) is applied to the first reference connection contact (15A), and the first Schottky diode (D1) opens when the second reference potential (VRef2) is applied to the first reference connection contact (15A).

Description

The invention relates to a capacitive sensor device for an operating device of a vehicle for detecting an approach and / or contact, the sensor device having at least one first electrically conductive sensor electrode for capacitive detection of the presence of an input means in a detection area of the sensor device, which interacts with the environment Presence of an input means in the detection area of the sensor device forms changing sensor capacitance, as well as a control and evaluation device with a first connection contact, at least one first connection line, at least one first reference capacitance, at least one first electrical resistor, and a first reference connection contact that can be acted upon with a defined reference potential. The first sensor electrode is connected or can be connected to the first connection contact of the control and evaluation device via the first connection line and via the first electrical resistor. The first reference capacitance is, on the one hand, connected or connectable to the first connecting line between the first connection contact and the first electrical resistor and, on the other hand, to a base potential.

The present invention also relates to a method for operating such a capacitive sensor device.

Generic, capacitive sensor devices and corresponding methods for operating such sensor devices are known in principle from the prior art, for example from US Pat DE 299 24 441 U1 , the US 9,823,798 B2 or the one not yet published at the time of registration DE 10 2019 128 656 , whereby a wide variety of configurations are known, which differ mainly in their structure or in relation to the method in the control of the individual components.

Against this background, it is an object of the invention to provide an alternative capacitive sensor device, in particular an improved capacitive sensor device, preferably a capacitive sensor device, which has lower parasitic capacitances and / or lower leakage currents. Another object of the invention is to provide a method for operating such a sensor device.

According to the invention, this object is achieved by a capacitive sensor device and by a method for operating such a sensor device with the features according to the respective independent claims. Advantageous embodiments of the invention are the subject matter of the dependent claims, the description and the figures.

A capacitive sensor device designed and in particular set up according to the present invention for an operating device of a vehicle for detecting an approach and / or contact has a first electrically conductive sensor electrode for capacitive detection of the presence of an input means in a detection area of the sensor device as well as a control and evaluation device a first connection contact, a first connection line, in particular a measuring line, a first reference capacitance, a first electrical resistor, in particular a first ohmic resistor, and a first reference connection contact that can be acted upon with a defined reference potential. The sensor electrode forms with the environment a sensor capacitance that changes when an input means is present in the detection area of the sensor device and is or can be connected to the first connection contact of the control and evaluation device via the first connection line and via the first electrical resistor, in particular electrically, ie in particular galvanic. The first reference capacitance is connected or connectable to the first connection line between the first connection contact and the first electrical resistor, preferably via a first connection node, in particular electrically, and on the other hand to a base potential, preferably a zero potential, in particular a ground potential.

A capacitive sensor device according to the present invention is characterized in that the sensor device furthermore has a first Schottky diode, via which the first sensor electrode is further connected or connectable to the first reference connection contact, the first reference connection contact optionally defined with a first one Reference potential or a second defined reference potential can be applied, the first reference potential being greater than the threshold voltage of the first Schottky diode and the first sensor electrode being connected or connectable to the first reference terminal contact via the first Schottky diode in such a way that the first Schottky The diode blocks when the first reference potential is applied to the first reference connection contact, and the second reference potential is less than the threshold voltage of the first Schottky diode and the first sensor electrode is connected to the first reference via the first Schottky diode. Connection contact connected or connectable is that the first Schottky diode opens when the second reference potential is applied to the first reference connection contact.

A sensor device according to the invention, in which the connection of the sensor electrode to the reference connection contact is realized via a Schottky diode, has the advantage, in particular compared to a connection of the sensor electrode to the reference connection contact via a transistor switching device or a transistor switching element, such as it e.g. the DE 10 2019 128 656 suggests that the Schottky diode has a lower parasitic capacitance than a transistor switching device, for example than a MOSFET or a bipolar transistor, and that there is a lower leakage current than with a transistor switching device, for example a MOSFET or a bipolar transistor , as a result of which a higher sensor accuracy can be achieved, since the lower parasitic capacitance and the lower leakage current result in a lower, undesired influence, in particular falsification, of the sensor capacitance. This advantage becomes greater, the more correspondingly connected sensor electrodes a corresponding sensor device has. Furthermore, with a sensor device according to the invention, a capacitive sensor device can be provided which only requires one sensor electrode, but which nevertheless basically enables a continuity test, which will be explained in more detail below.

An “input means” in the sense of the present invention is an input means that causes a change in the capacitive coupling of an environment with the sensor electrode when it comes into the detection range of the sensor device, such as a capacitive input pen or a human hand or parts thereof, such as a finger of a human hand or the like.

In the context of the present invention, the term “detection area” is understood to mean an area, in particular a spatial area, within which an approach and / or contact can be detected, i.e. recognized.

In the context of the present invention, a “control and evaluation device” is understood to mean a combined control and evaluation device which is set up on the one hand to control the sensor device, in particular individual components of the sensor device, in particular corresponding circuit devices, arrangements and / or the like, that a corresponding method for operating the sensor device can be carried out, in particular steps a) to e) of a method according to the invention, and which, on the other hand, is set up to evaluate the detected voltage according to step f). The control and evaluation device is preferably a microcontroller or part of a microcontroller. More than one control and evaluation device can also be provided.

A “connection contact” in the sense of the present invention can be, for example, a connection pin of a corresponding plug contact or a connection contact of a printed circuit board. However, a connection contact does not have to be a pin or the like, but can in principle be any electrical contact, for example any electrical connection contact on a circuit board, for example a soldering contact or the like. This means that a connection contact does not necessarily have to represent an input or output.

A “sensor electrode” of a sensor device according to the invention is in particular an electrically conductive element or an electrically conductive structure for the capacitive detection of an approach and / or contact of an input means, for example a user interface and / or for the detection of a touch of a user interface of an operator control device with the input means, wherein the sensor electrode can preferably form a sensor surface, in particular the user interface of the operating device, or can be arranged below a user surface in an associated operating device, optionally with a dielectric in between.

In the context of the invention, the term “reference potential” is understood to mean a defined electrical potential which is used in particular to establish a defined (reference) state of the sensor device during operation of a sensor device according to the invention and / or in preparation for operation.

In an advantageous embodiment of a sensor device according to the invention, the first electrical resistor is connected or switchable in series between a connection node, via which the reference capacitance is connected to the first connection line, and the sensor electrode. A particularly simple and advantageous arrangement of the individual components of the sensor device can thereby be achieved.

In a particularly advantageous embodiment of a sensor device designed according to the present invention, the sensor device is designed and set up to be operated based on the so-called “capacitive voltage divider method” (CVD method), which is basically known from the prior art, for example from the aforementioned US 9,823,798 B2 , and in particular goes back to the company "Microchip", as well as from the not yet published at the time of this application DE 10 2019 129 802 , to which reference is hereby expressly made for more detailed information.

The first reference capacitance is used in particular to provide a defined charging potential for charge equalization, whereby a particularly advantageous, particularly accurate, sensor device can be provided, the first reference capacitance being able to be charged with a defined charging potential, in particular via the associated first connection line.

In the context of the invention, the term “charging potential” is understood to mean a defined electrical potential which can be selected in particular as required and which can be set, for example, to + 5V or -5V. In a particularly simple embodiment, the charging potential can be the potential of a supply voltage of the control and evaluation device, for example the potential of the positive supply voltage VDD or VCC, as it is sometimes also referred to, which in a vehicle is preferably between + 10V and + 14V, especially around + 12V.

The first electrical resistor enables, in particular, a decoupling of the first reference capacitance from the first sensor electrode in the charging cycle and thus the defined charging of the reference capacitance, in particular quickly and precisely, whereby a particularly good detection accuracy of the sensor device can be achieved, in particular a high resolution or short scanning cycles.

In a preferred embodiment of a sensor device according to the present invention, the sensor device is also designed and set up in such a way that the first reference connection contact can have a first reference potential applied to it, which is preferably greater than + 3V, + 5V or + 10V or even more is above this, in particular if the first Schottky diode is selected in such a way that its parasitic capacitance decreases as the level of the applied reference potential increases, which is particularly preferably the case.

The first Schottky diode is preferably selected in such a way that its parasitic capacitance decreases in a hyperbolic manner with increasing reference potential, for example as in FIG 4th shown.

In a preferred embodiment of a sensor device according to the present invention, the sensor device is designed and set up in such a way that the second reference potential to which the first reference terminal contact reference potential can be applied is a zero potential (0V), in particular a ground potential ( GND ). Such a potential is, on the one hand, always below the threshold voltage of a Schottky diode and, on the other hand, can be provided particularly easily, especially in a vehicle. This enables a particularly easy-to-implement method for operating a sensor device according to the invention, in particular a particularly advantageous implementation of the operation of the sensor device, in particular according to a method according to the invention.

In a further advantageous embodiment of a sensor device according to the present invention, the sensor device also has an electronic switching device which is designed and configured to be switched between a first switching state and a second switching state, with when the electronic switching device is in the first switching state , the first reference potential is applied to the first reference connection contact so that the first Schottky diode blocks, ie has a high resistance, and when the electronic switching device is in the second switching state, the second reference potential is applied to the first reference connection contact, so that the first Schottky diode opens, ie acts with low resistance. Such an electronic switching device enables the first reference potential or the second reference potential to be selectively applied to the first reference connection contact, in particular in a targeted manner, in a particularly simple manner.

In a further advantageous embodiment of a sensor device according to the present invention, in particular in a further development, the electronic switching device has for this purpose a control switching device which can be switched from a first switching state to a second switching state, with the control switching device being switched to the first Switching state causes the first reference potential to be set at the first reference connection contact and switching the control switching device to the second switching state causes the second reference potential to be set at the first reference connection contact. The control switching device can be an assembly of several switching elements or just a single switching element, for example a transistor switching element or the like, such as a MOSFET (metal-oxide-semiconductor field-effect transistor) or a bipolar transistor.

In a further advantageous embodiment of a sensor device according to the present invention, the sensor device also has a first connection to which the first reference potential is applied, and a second connection to which the second reference potential is applied, the first reference connection contact being connected or connectable to the first connection and to the second connection, in particular via a reference line. This makes it possible to achieve a particularly advantageous embodiment or configuration of a sensor device according to the invention, in particular a particularly advantageous spatial arrangement of the individual components and a particularly simple arrangement.

Particularly preferably, the first reference connection contact is connected or connectable to the first connection and the second connection via the reference line in such a way that it is located between the first connection and the second connection, so that the first Schottky diode is between the first connection and the second connection is connected or connectable to the reference line via the reference connection node. In this way, a particularly advantageous spatial arrangement of the individual components of the sensor device can be achieved.

The first terminal is preferably connected or connectable directly to the first reference potential, in particular electrically, preferably to a first pole of a reference voltage source, and the second terminal to the second reference potential, in particular to a second pole of the reference voltage source. This allows the first reference potential and the second reference potential to be provided in a simple manner. In this way, a corresponding application of the corresponding reference potential to the first reference connection contact can be achieved particularly easily via the reference line, in particular in connection with an electronic switching device.

In a further advantageous embodiment of a sensor device according to the present invention, the sensor device, in particular the electronic switching device, has at least one further electrical resistor, preferably an ohmic resistor, in particular a pull-up resistor, the first reference connection contact via this further electrical resistor is connected or connectable to the first terminal, preferably electrically, ie galvanically, in particular by means of the reference line. A further electrical resistor connected in this way, in conjunction with a correspondingly designed and connected control switching device, makes it possible to provide a particularly simply constructed, electronic switching device which is designed and set up to be switched between a first switching state and a second switching state in such a way that, when the electronic switching device is in the first switching state, the first reference potential is applied to the first reference connection contact so that the first Schottky diode blocks, and when the electronic switching device is in the second switching state, the second reference potential is applied to the first reference connection contact so that the first Schottky diode opens.

In a further advantageous embodiment of a sensor device according to the present invention, the first reference connection contact is also connected or can be connected to the second connection via the control switching device, in particular by means of the reference line, preferably via another line section of the reference line, in particular such that between the first connection and the second connection, in particular along the reference line, the further electrical resistor and the control switching device are connected in series, wherein the first reference connection contact is preferably located between the further electrical resistor and the control switching device. In this way, a particularly simple electronic switching device and thus a particularly advantageous sensor device can be provided.

In a further possible, particularly preferred embodiment of a sensor device according to the invention, the further electrical resistor, in particular if this is a pull-up resistor, and / or the electronic control switching device, in particular also, can be part of the electronic switching device. This enables a particularly simple modular structure.

Alternatively, the further resistor can also be a pull-down resistor, this requiring a correspondingly different arrangement of the further electrical resistor and the control switching device relative to the first and second connection, in particular an arrangement as is basically known from the prior art, in order to apply a first or second reference potential to an electrical line or a connection contact optionally and depending on the switching state of the control switching device.

The electronic switching device or parts or components thereof, for example the control switching device and / or the further electrical resistor, can in principle both be arranged outside of the control and evaluation device, or alternatively also be integrated into the control and evaluation device, wherein in in this case then preferably the design and arrangement of the associated and connection contacts and any connection lines that may be required are adapted accordingly. If the electronic control device is integrated into the control and evaluation device, for example, the control and evaluation device preferably has corresponding connection contacts for connecting the electronic control device to a corresponding voltage source and / or a correspondingly suitable voltage source integrated in the control and evaluation device with which the electronic control device is connected or connectable.

In a further advantageous embodiment of a sensor device according to the present invention, in particular in a further development, the sensor device also has a second connection line, in particular a control line, and the control and evaluation device furthermore has a second connection contact, the control switching device preferably via the second Connection line is connected or connectable to the second connection contact of the control and evaluation device. Particularly preferably, the control and evaluation device is also designed and set up to switch the control switching device, in particular via the second connection line, at least between a first switching state and a second switching state, in particular with the aid of a correspondingly via the second connection contact from the control and switching device Evaluation device can be outputted and transmitted via the second connection line control signal, which in particular can also be generated by the control and evaluation device. The control and evaluation device is particularly preferably designed and set up to output a control signal to the control switching device via the second connection contact and the second connection line. In this way, a particularly simple control of the sensor device can be achieved, in particular a particularly simple synchronization with a detection or measurement of the sensor capacitance. In particular, no additional control device is required. Alternatively or additionally, however, the control switching device can also be activated by a further control device, in particular designed separately from the control and evaluation device of the sensor device.

In a particularly advantageous embodiment of a sensor device according to the present invention, the first connection contact and / or the second connection contact can each be switchable as an input and / or output and in particular each be designed as a so-called GPIO contact, ie in particular as a so-called "general Purpose Input Output ”contact, which can optionally be assigned different functions or signals depending on the switching state, the sensor device, in particular the control and evaluation device of the sensor device, preferably having at least one input and / or output port, in particular one switchable input and / or output port to which the first connection contact and / or the second connection contact is assigned, wherein at least one input and / or output port is preferably designed and set up to output a, in particular defined, voltage, a Detect tension, e To apply a respective, associated connection contact to a, in particular a defined, potential and / or to switch the respective connection contact to a high or low resistance.

The first connection contact and the second connection contact can be assigned to a common input and / or output port, i.e. a common channel or different input and output ports.

Both connection contacts can preferably each be switched as an output, in particular by switching them to low resistance, i.e. to "LOW", and more preferably alternatively as an input by switching them to high resistance, i.e. to "HIGH".

A particularly defined charging potential can preferably be applied to at least one connection contact, in particular to at least one connection pin of an input and / or output port, in particular at least to the first connection contact, in particular to at least the first connection contact, for example a charging potential of + 5V, in particular a supply voltage, preferably the positive supply voltage of the control and evaluation device, and a control potential can be applied to another connection contact, preferably to the second connection contact, in particular to at least one other connection pin of the port.

In a further advantageous embodiment of a sensor device according to the invention, in particular in a further development, the sensor device has at least one analog-digital converter, preferably for detecting at least one voltage present on at least one connection contact, in particular on the first connection contact, the at least one analog-digital -Converter can be coupled in particular to at least one input and / or output port, in particular can be electrically connected, preferably at least one analog-to-digital converter via an input and / or output port to the associated connection contact is electrically connectable, in particular switchable contactable, so that in particular at least one input of an analog-digital converter can be connected to at least one connection contact. A sensor device according to the invention can also have several analog-digital converters.

In a further advantageous embodiment of a sensor device according to the present invention, the control switching device, as already mentioned above, can have a field effect transistor or be a field effect transistor. In this way, a particularly simple electronic switching device and thus a particularly advantageous sensor device can be provided. In conjunction with the further electrical resistor, which is particularly preferably connected in series with the field effect transistor along a reference line, this enables a particularly simple switchover between the first reference potential and the second reference potential at the first reference terminal contact.

For a particularly simple electronic switching device, therefore, the further electrical resistor and the control switching device, in particular an associated field effect transistor, are preferably connected in series along a reference line, with a first end of the reference line preferably being or connectable to the first terminal, to which in particular the first reference potential is applied, and more preferably a second end of the reference line is or can be connected to the second terminal, to which in particular the second reference potential is applied.

In a further advantageous embodiment of a sensor device according to the present invention, in particular in a further development, the field effect transistor is a metal-oxide-semiconductor field effect transistor (MOSFET), the second connection contact of the control and evaluation device preferably being connected to the second connection line Gate terminal of the field effect transistor is connected or connectable. In principle, however, a bipolar transistor is also possible as an alternative.

In most cases, however, a MOSFET is more advantageous than a comparable bipolar transistor, since it usually leads to a lower voltage drop than a bipolar transistor with other comparable properties in the on state, ie in the conductive state, in particular in a lower voltage drop in the conductive state between drain and source connection than a bipolar transistor in the on state, ie in the conductive state, between collector and emitter. As a result of the lower voltage drop of the MOSFET, the sensor capacitance can be better discharged, i.e. pulled down to a lower voltage level, before potential equalization with the potential applied to the associated reference capacitance after charging. As a result, a greater potential difference can be achieved between the reference capacitance and the sensor capacitance before the potential equalization and thus a higher accuracy of the sensor device, in particular as a result of the improved sensitivity or improved resolution of the sensor device brought about by the above effects.

In a particularly preferred embodiment of a sensor device according to the invention, the drain connection of the MOSFET is preferably connected or connectable to the first connection, in particular electrically, ie galvanically, the first reference potential being particularly preferably applied to the first connection, and the source connection of the MOSFET in particular with the second connection, at which a zero potential (0V), in particular ground ( GND ) is present.

If the field effect transistor of the control switching device is a bipolar transistor, the collector connection of the bipolar transistor is preferably connected or connectable to the first connection, in particular electrically, ie galvanically, the first reference potential being particularly preferably applied to the first connection, and the Source connection of the bipolar transistor, in particular with the second connection, at which a zero potential (0V), in particular ground ( GND ) is present.

In a further advantageous embodiment of a sensor device according to the present invention, in addition to the first electrically conductive sensor electrode, the sensor device has at least one further electrically conductive sensor electrode for capacitive detection of the presence of an input means in a detection area of the sensor device, which also forms a sensor capacitance with the surroundings, in particular a further sensor capacitance in each case, the further sensor capacitance also changing in each case when an input means is present in the detection area of the sensor device, the sensor device preferably also having a further first connection line assigned to the further sensor electrode, a further reference capacitance assigned to the further sensor electrode and has a further first electrical resistor assigned to the further sensor electrode. The control and evaluation device particularly preferably has for at least one further sensor electrode, in particular for each further sensor electrode, furthermore a further first connection contact assigned to the further sensor electrode, wherein in particular at least one further sensor electrode is connected via the associated further first connection line, that is to say assigned to this further sensor electrode, and via the associated further first electrical resistor with the associated further The first connection contact of the control and evaluation device is or can be connected, and wherein the further reference capacitance associated with the at least one further sensor electrode is connected on the one hand between the associated further first connection contact and the associated further first electrical resistor to the associated further first connection line or can be connected, preferably via a corresponding further first connection node, and on the other hand to one or the base potential, preferably a zero potential, in particular a ground potential, verb unden or can be connected, in particular electrically, ie galvanically.

Particularly preferably, a sensor device embodied in this way with a plurality of sensor electrodes also has a plurality of analog-digital converters for detecting an applied voltage on the connection contact assigned to a respective sensor electrode, in particular on the first connection contact assigned to the sensor electrode. In this way, the sensor capacitances or their changes can be recorded separately for the individual sensor electrodes, with a sensor device according to the present invention being particularly preferably designed in such a way that the sensor capacitances or their changes in all sensor electrodes can be recorded separately, in particular at the same time.

By means of such a sensor device, a separate detection of a capacitive approach and / or contact in different areas of a user interface, i.e. spatially resolved, is possible in a particularly simple manner. The multiple sensor electrodes required for this can be integrated into the sensor device in a particularly simple manner, in particular with only little additional effort. In particular, in addition to the respective sensor electrode, only a few further components or only minor changes / adjustments to the components that are basically present in a sensor device according to the invention are required.

In a further, particularly advantageous embodiment of a sensor device according to the present invention, the sensor device also has at least one further Schottky diode assigned to a further sensor electrode, the at least one further sensor electrode having a reference connection contact via the associated further Schottky diode, in particular an associated further reference terminal contact, is or can be connected, in particular analogously to the first Schottky diode and preferably via at least one associated, further reference terminal contact, in particular such that the reference potential applied to the further reference terminal contact on the further Schottky diode is present.

The respective reference terminal contact, in particular the associated further reference terminal contact, in particular likewise, can optionally be acted upon with a first defined reference potential or a second defined reference potential, the first reference potential being greater than the threshold voltage of the associated further Schottky diode is that the second reference potential is less than the threshold voltage and the further sensor electrode is connected or connectable via the associated, further Schottky diode to the reference connection contact, in particular to the respectively associated, further reference connection contact, that the associated, further Schottky -Diode blocks when the respective first reference potential is applied to the reference connection contact, in particular to the respective associated further reference connection contact, and opens when the respective second reference potential is applied to the reference connection contact, in particular e at the respective associated, further reference connection contact.

For this purpose, at least one associated, further reference connection contact is preferably connected or connectable to the first connection and to the second connection, in particular all further, associated reference connection contacts, in particular in each case via a further or a common reference line. In this way, one or more further reference connection contacts can each have a respective first reference potential and a respective second reference potential applied to them in a particularly simple manner, the reference potentials and / or the at least one further Schottky diode being selected such that the respective Schottky diode opens or blocks in a manner analogous to the first Schottky diode, depending on the reference potential applied to the respective reference connection contact.

Like the first Schottky diode, each additional Schottky diode has the advantage that it has a lower parasitic capacitance than a transistor switching device, for example than a MOSFET or a bipolar transistor, and there is less leakage current through the Schottky Diode comes as with a transistor Switching device, for example a MOSFET or a bipolar transistor, whereby a higher sensor accuracy can be achieved, since the lower parasitic capacitance and the lower leakage current result in a lower, undesired influence, in particular falsification, of the sensor capacitance. This advantage becomes greater, the more correspondingly connected sensor electrodes the sensor device has.

In principle, however, it is alternatively also possible to use one or more further sensor electrodes instead of a further Schottky diode via another switching device, for example via a tri-state switch or a transistor, as is the case with DE 10 2019 128 656 proposes to connect to the reference potential, but with the disadvantages of the larger parasitic capacitances and the larger leakage currents described above.

For a particularly simple construction of a sensor device according to the invention with more than one sensor electrode, two or more of the reference connection contacts, in particular all reference connection contacts, are particularly preferably connected or connectable to one another via a common reference line, in particular electrically. As a result, the respective reference connection contacts can be acted upon in a first cycle at the same time with the same first reference potential and / or in a second cycle with the same second reference potential. A separate synchronization is no longer necessary.

A further electrical resistor and a control switching device are particularly preferably connected in series along a reference line and the reference connection contacts, in particular, connected or connectable, preferably electrically, to the reference line between the respective further electrical resistor and the control switching device.

In a particularly advantageous embodiment of a sensor device according to the present invention, only one common reference line is provided and thus only one further electrical resistor and only one control switching device.

In a further advantageous embodiment of a sensor device according to the present invention, the sensor device also has at least one second electrical resistor assigned to a sensor electrode, in particular an ohmic resistor, which is connected in series with the first electrical resistor assigned to the respective sensor electrode, so that the sensor electrode is connected or connectable via the associated first connection line, via the associated, first electrical resistor and the associated second electrical resistor to the associated first connection contact of the control and evaluation device, wherein the first electrical resistor and the second electrical resistor are preferably selected such that the first electrical resistance is much greater than the second electrical resistance, the first electrical resistance in particular being at least ten times as large as the second electrical resistance che resistance. In this way, an improved decoupling of the sensor electrode can be achieved, in particular a discharge of the sensor capacitance can be stabilized.

The first electrical resistance and the second electrical resistance as well as the associated reference capacitance of at least one sensor electrode, in particular each, are particularly preferably selected and the sensor electrode is designed such that the mathematical product of the associated reference capacitance and the associated first electrical resistance is very much greater as the mathematical product of a nominal capacitance of the sensor electrode and the associated second electrical resistance, the product of the associated reference capacitance and the associated first electrical resistance in particular at least 10 times the product of the nominal capacitance of the sensor electrode and the second electrical resistance amounts to. It has been shown that such coordination is particularly advantageous with regard to an achievable detection accuracy of a sensor device according to the invention.

In a further advantageous embodiment of a sensor device according to the present invention, the first sensor electrode and / or at least one further sensor electrode has a first electrode connection, at least one sensor electrode via this first electrode connection with the associated first connection line, that is to say assigned to this sensor electrode, and via this as well is connected or connectable via the associated first electrical resistor to the associated first connection contact of the control and evaluation device, and wherein at least one sensor electrode is also connected or connectable to the associated reference connection contact via this first electrode connection and via the associated Schottky diode, preferably in each case with the aid of an associated third connection node and a further connection line and in particular in each case via the second connection node. In this way, a particularly simple structure of a sensor device according to the invention can be implemented.

Alternatively, however, at least one sensor electrode can also have two electrode connections, as is the case, for example, in that already mentioned at the beginning DE 10 2019 129 802 is detailed. Assuming a suitably suitable configuration of the sensor device, this enables a continuity test of the sensor electrode and thus the provision of a sensor device with improved diagnostic properties.

In a further advantageous embodiment of a sensor device according to the invention, in particular in a further development, the sensor device can furthermore have an electrically conductive shielding electrode, in particular a shielding electrode arranged between the first connecting line and the second connecting line, the shielding electrode preferably and preferably at least temporarily, in particular permanently, during an operation of the sensor device can be acted upon with a defined electrical potential, in particular with a potential that tracks the detected voltage profile over time, and in particular the control and evaluation device is set up to at least temporarily, in particular permanently, the shielding electrode during the execution of a method according to the invention to apply a defined potential, in particular with a potential that tracks the detected voltage profile over time. This makes it possible to reduce undesirable interfering influences, which can lead to a falsifying influence on the capacitive coupling of the sensor electrode with the environment and / or to an undesired influence from other components of the sensor device. As a result, higher accuracy can be achieved with the sensor device.

In a particularly advantageous embodiment of a sensor device designed according to the present invention, the sensor device is designed and set up to be operated in accordance with a method according to the invention, which is described in more detail below.

1. a) Bereitstellen einer erfindungsgemäßen Sensorvorrichtung,
2. b) Aufladen wenigstens einer Referenzkapazität, insbesondere sämtlicher Referenzkapazitäten, indem jeweils ein definiertes Ladepotential an den zugehörigen ersten Anschlusskontakt der Steuerungs- und Auswerteeinrichtung angelegt wird,
3. c) Entladen wenigstens einer mit der Umgebung gebildeten Sensorkapazität wenigstens einer Sensorelektrode, insbesondere sämtlicher mit der Umgebung gebildeten Sensorkapazitäten, indem ein definiertes Referenzpotential an den zugehörigen Referenz-Anschlusskontakt angelegt wird, vorzugsweise ein zweites Referenzpotential, insbesondere ein Nullpotential, welches bewirkt, dass die jeweilige Schottky-Diode öffnet, über welche die zugehörige Sensorelektrode mit dem zugehörigen Referenz-Anschlusskontakt elektrisch verbunden oder verbindbar ist,
4. d) Herbeiführen eines Potentialausgleichs zwischen wenigstens einer Referenzkapazität und der zugehörigen Sensorkapazität der zugehörigen Sensorelektrode, insbesondere zwischen sämtlichen Referenzkapazitäten und der jeweils zugehörigen Sensorkapazität, wobei dazu insbesondere der zugehörige erste Anschlusskontakt der Steuerungs- und Auswerteeinrichtung hochohmig geschaltet wird und ein definiertes Referenzpotential an den zugehörigen Referenz-Anschlusskontakt angelegt wird, vorzugsweise ein erstes Referenzpotential, welches bewirkt, dass die jeweilige Schottky-Diode sperrt, über welche die zugehörige Sensorelektrode mit dem zugehörigen Referenz-Anschlusskontakt elektrisch verbunden oder verbindbar ist,
5. e) Erfassen wenigstens einer anliegenden Spannung an wenigstens einem ersten Anschlusskontakt der Steuerungs- und Auswerteeinrichtung, insbesondere an sämtlichen ersten Anschlusskontakten, und
6. f) Auswerten der erfassten Spannung.

A method according to the invention for operating a sensor device designed according to the present invention is characterized by the steps:

1. a) providing a sensor device according to the invention,
2. b) charging at least one reference capacitance, in particular all reference capacitances, by applying a defined charging potential to the associated first connection contact of the control and evaluation device,
3. c) discharging at least one sensor capacitance formed with the environment of at least one sensor electrode, in particular all sensor capacitances formed with the environment, by applying a defined reference potential to the associated reference terminal contact, preferably a second reference potential, in particular a zero potential, which causes the respective Schottky diode opens, via which the associated sensor electrode is electrically connected or can be connected to the associated reference connection contact,
4. d) Bringing about equipotential bonding between at least one reference capacitance and the associated sensor capacitance of the associated sensor electrode, in particular between all reference capacitances and the respective associated sensor capacitance, in particular the associated first connection contact of the control and evaluation device being switched to high resistance and a defined reference potential to the associated reference -Connection contact is applied, preferably a first reference potential, which causes the respective Schottky diode to block, via which the associated sensor electrode is electrically connected or can be connected to the associated reference connection contact,
5. e) detecting at least one applied voltage on at least one first connection contact of the control and evaluation device, in particular on all first connection contacts, and
6. f) Evaluation of the recorded voltage.

Steps b) and c) can be carried out simultaneously or one after the other, step c) preferably not being carried out until after step b), while steps d), e) and f) are carried out one after the other in the order mentioned in particular only be carried out when steps b) and c) have been carried out to the end.

After the equipotential bonding has been brought about, the voltage set by the equipotential bonding and then applied changes, which is in particular also referred to as the equivalent comparison voltage when an input means penetrates the detection area, the resulting voltage change being proportional to the distance between the input means and the sensor electrode, so that on the basis of the detected voltage it can be recognized whether an input means is located in the detection area of the sensor device or not, in particular at what distance, so that in particular a touch can be distinguished from an approach. Accordingly, can by evaluating the voltage it can be determined whether an input means, for example a human hand, is located in the detection area of the sensor device or not.

In an advantageous embodiment of a method according to the present invention, in order to apply the charging potential to the first connection contact or to the first connection contacts of the control and evaluation device in step b), the connection contact is switched as an output, in particular by switching to low resistance, ie to "LOW" . This enables particularly efficient charging of the associated reference capacitance (s).

In a further advantageous embodiment of a sensor device according to the present invention, the sensor device is therefore designed and set up in such a way that, in order to apply the charging potential to one of the first connection contacts of the control and evaluation device in step b), the first connection contact can be switched as an output, wherein to this end, in particular the first connection contact can be switched to a low resistance.

The switching of the two connection contacts can be implemented particularly easily by means of a control and evaluation device in which the first connection contact and the second connection contact are each part of a so-called GPIO connection ("General Purpose Input / Output connection"), ie as a general one , switchable connection contact, which can be achieved particularly easily by assigning the respective connection contact to an input and / or output port, in particular a switchable input and / or output port.

Preferably, in particular in a further development, the first connection contact and the second connection contact are assigned to a common input and / or output port, ie a common channel, which preferably allows different occupancy, for example with different potentials etc., but in particular can only be controlled logically together. If the first connection contact and the second connection contact are each assigned to one and the same input and / or output port, a synchronization of the two connection contacts can be achieved in a particularly simple manner, whereby short scanning cycles and thus a high resolution can be achieved. In addition, a high level of sensor sensitivity can be achieved in this way, since the synchronization enables a defined initial state to be set reliably and precisely before the start of each measurement. Alternatively, however, an assignment of the two connection contacts to different input and / or output ports is also conceivable.

In a particularly advantageous embodiment of a sensor device according to the invention, the sensor device has a first analog-digital converter and at least one second analog-digital converter formed separately from the first analog-digital converter, each of the two analog-digital converters preferably in each case can be coupled to at least one input and / or output port, in particular can be electrically connected.

If two or more analog-to-digital converters are provided, these can either be assigned to the same input and / or output port, different input and / or output ports and / or different control and evaluation devices, the sensor device for the latter preferably has correspondingly more than one control and evaluation device.

In a further step of a method according to the invention, in particular in an advantageous embodiment of a method according to the invention, a sensor signal can be generated and output depending on the evaluation result, which in particular contains at least one piece of signal information as to whether or not an input means is in the detection area of the sensor device.

In a particularly advantageous embodiment of a method according to the present invention, to apply the defined reference potential in steps c) and d) to the associated reference connection contact, the control switching device is preferably via the second connection contact of the control and evaluation device and the second connection line from the controller - and evaluation device controlled, whereby to apply a reference potential, which causes the respective Schottky diode to block, via which the associated sensor electrode is electrically connected or can be connected to the associated reference connection contact, in particular to apply a first reference potential, and thus to bring about of the equipotential bonding in step d), the control switching device is preferably switched to a first switching state, in particular in a high-resistance and thus non-conductive, blocked switching state, or is held in this, and wherein ei nes reference potential, which causes the respective Schottky diode to open, via which the associated sensor electrode is electrically connected or can be connected to the associated reference connection contact, in particular for applying a second reference potential, and thus for discharging at least one sensor capacitance formed with the environment a sensor electrode in step b), the control switching device is preferably switched into a second switching state, in particular into a low-resistance and therefore conductive, open switching state, or is held in this.

In this way, the respective reference connection contact can be subjected to the respective, desired reference potential in a particularly simple manner.

If the reference connection contacts are each connected to one another via a common reference line, only a second connection contact, a second control line and only one control switching device are required to switch between the first reference potential and the second reference potential at the reference connection contacts. This makes it possible to provide a particularly simple and, in particular, only a few components comprising and therefore particularly cost-effective, advantageous sensor device.

The preferred embodiments presented with reference to a capacitive sensor device according to the invention and their advantages also apply accordingly to a method according to the invention for operating such a sensor device and vice versa, even if this is not explicitly explained in the present application, in particular to avoid repetitions.

Further features of the invention emerge from the claims, the figures and the description of the figures. All of the features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown on their own in the figures can be used not only in the respectively specified combination, but also in other combinations or on their own, provided that this combination is technically feasible.

• 1 ein Blockschaltbild einer aus dem Stand der Technik bekannten, kapazitiven Sensorvorrichtung,
• 2 ein Blockschaltbild eines ersten Ausführungsbeispiels einer erfindungsgemäßen kapazitiven Sensorvorrichtung,
• 3 ein Blockschaltbild eines zweiten Ausführungsbeispiels einer erfindungsgemäßen kapazitiven Sensorvorrichtung,
• 4 ein Diagramm, in welchem für ein Ausführungsbeispiel einer Schottky-Diode beispielhalber ein Verlauf einer internen, parasitären Kapazität der Schottky-Diode in Abhängigkeit von einer an der Schottky-Diode anliegenden Spannung dargestellt ist,
• 5 ein Blockschaltbild eines dritten Ausführungsbeispiels einer erfindungsgemäßen kapazitiven Sensorvorrichtung, und
• 6 ein Blockschaltbild eines vierten Ausführungsbeispiels einer erfindungsgemäßen kapazitiven Sensorvorrichtung.

The invention will now be explained in more detail on the basis of several non-restrictive exemplary embodiments and with reference to the accompanying drawings, components with the same function being provided with the same reference numerals. Show:

• 1 a block diagram of a capacitive sensor device known from the prior art,
• 2 a block diagram of a first embodiment of a capacitive sensor device according to the invention,
• 3 a block diagram of a second embodiment of a capacitive sensor device according to the invention,
• 4th a diagram in which, for an exemplary embodiment of a Schottky diode, a profile of an internal, parasitic capacitance of the Schottky diode is shown as a function of a voltage applied to the Schottky diode,
• 5 a block diagram of a third embodiment of a capacitive sensor device according to the invention, and
• 6th a block diagram of a fourth embodiment of a capacitive sensor device according to the invention.

1 shows a block diagram of a generic sensor device known from the prior art 1 such as in the DE 10 2019 128 656 is described, the sensor device 1 two electrically conductive sensor electrodes 3 for the capacitive detection of the presence of an input means in a detection area of the sensor device 1 having, wherein the sensor electrodes 3 each with the environment when an input means is present in the detection area of the sensor device 1 changing sensor capacitance 4th form. Furthermore, the capacitive sensor device 1 a control and evaluation device 8th on which two first connection contacts 9 and a second connection contact 10 has, and which both with a zero potential, in this case with ground ( GND ) is connected, in particular electrically, ie galvanically, and which is also connected or connectable to a supply voltage, for example a supply voltage in a vehicle of in particular + 12V or the like, but this is shown in 1 is not shown.

In the 1 Sensor device shown 1 each has a plurality of first connection lines 11 each with the first connection contact 9 are connected and in particular each as a measuring line 11 serve, the sensor electrodes 3 in each case via these first connection lines 11 and an electrical resistor connected along these lines 7th , which is in particular an ohmic resistor, with the respective associated first connection contact 9 the control and evaluation device 8th are connected.

Via a first connection node 14th is also a reference capacitance 5 on the one hand with the first connection line 11 connected and on the other hand with a base potential, in this case each with a ground potential GND , ie with a zero potential (0V).

Via a second connection node 12th and one electronic switching device in each case 6th can use the sensor electrodes 3 furthermore are each also connected to a ground potential.

At the in 1 sensor device shown 1 can use the two electronic switching devices 6th in each case by means of a common second connection line 13th , which serves in particular as a control line, are controlled, the associated control signal from the control and evaluation device 8th can be generated and via a second connection contact 10 on the second connection line 13th , ie the control line 13th , can be output.

In the 1 Sensor device shown 1 can in particular be operated according to the CVD method, which is also fundamentally known from the prior art, with the reference capacitances for this purpose in a first step 5 in each case via the first connection contacts 9 and the first connection line in 11 can be charged in a defined manner with a defined charging potential, and the sensor electrodes 3 or the sensor capacities formed by these with the environment 4th each by connecting to a ground potential ( GND ) are discharged, with the associated electronic switching devices 6th each from the control and evaluation device 8th via the second connection contact 10 and the common control line 13th can be controlled in such a way that the switches of the electronic switching devices 6th close, with the electronic switching devices 6th in particular each have a transistor or a tri-state switch as a corresponding switching element.

In a next step, especially after the reference capacities 5 are fully and clearly charged, and the sensor electrodes 3 or the sensor capacities formed by these with the environment 4th are discharged in a defined manner, in particular almost completely, are the connections of the sensor electrodes 3 separated with the ground potential, with the electronic switching devices 6th from the control and evaluation device 8th , can be controlled accordingly, in particular can be switched over in such a way that the connection between the second connection node in each case 12th and the ground potential is separated.

Furthermore, the first connection lines 11 or the first connection contacts 9 be separated from the charging potential, which can be easily implemented, for example, using the corresponding GPIO inputs and outputs by switching them to high resistance.

As a result, there is potential equalization between the respective reference capacitance 5 and the associated sensor capacitance 4th a sensor electrode 3 and an equivalent equivalent voltage is established.

If a corresponding input means is now placed in the vicinity of one of the sensor electrodes 3 brought, in particular in their detection area, the capacitive coupling of the sensor electrode changes 3 with the environment and, as a result, the comparison voltage set by the equipotential bonding, which is measured in terms of the associated first connection line 11 that yes as a test lead 11 is used by the control and evaluation device 8th can be captured.

The control and evaluation device 8th for example, corresponding devices, not shown here, for detecting the change in the capacitive coupling of the sensor electrode 3 have with the environment, for example one or more analog-digital converters, which, in particular after bringing about the potential equalization, each with the corresponding first connection lines 11 or the associated first connection contacts 9 can be connected.

2 shows a block diagram of a first embodiment of a capacitive sensor device according to the invention 100 , the sensor device 100 is provided for a control device of a vehicle, not shown here, for example for a steering wheel control device, which can be operated in particular at least partially by an input means approaching a control surface and / or by touching a control surface with an input means, the detection of an approach and / or touching the user interface takes place capacitively.

According to the invention, the sensor device 100 a first electrically conductive sensor electrode E1 for capacitive detection of the presence of an input means, such as a human hand or a finger of a human hand, in a detection area of the sensor device 100 on, with the sensor electrode E1 with the environment a sensor capacitance Cex- 1 forms, which occurs in the presence of a suitable input means in the detection area of the sensor device 100 changes, for example in the presence of a human hand.

Furthermore, the sensor device 100 a control and evaluation device 8th with a first connection contact 9 on as well as a first connection line 11 , which in particular as a measuring line 11 serves, the control and evaluation device 8th in this case in particular a microcontroller and the first sensor electrode E1 via the first connection line 11 with the first connection contact 9 the control and evaluation device 8th connected is.

This embodiment of a sensor device according to the invention 100 also has a second connection contact 10 as well as a second connection line 13th on, which in particular as a control line 13th serves.

According to the invention, the sensor device 100 furthermore a first reference capacitance C _Ref-1 on which by a capacitor C _Ref-1 is formed with a defined capacity, and which on the one hand with the first connection line 11 is electrically connected, in particular between the first connection contact 9 the control and evaluation device 8th as well as the sensor electrode E1 , in particular via a first connection node 14th , and on the other hand with a base potential VBasis, which in this case is preferably a ground potential ( GND ), ie a zero potential (0V).

Between the first reference capacitance C _Ref-1 and the sensor electrode E1 is further still a first electrical resistor according to the present invention R1 , in this case an ohmic resistor R1 , connected in series, in particular between the first connection node 14th over which the first reference capacitance C _Ref-1 with the first connection line 11 is electrically connected, and the sensor electrode E1 .

The sensor electrode E1 has a first electrical electrode connection for their electrical contacting 17th on over which the first sensor electrode E1 with the first connection line 11 and the first connection contact 9 the control and evaluation device 8th connected is.

According to the present invention, the sensor device 100 furthermore at least one first Schottky diode D1 on which the first sensor electrode E1 furthermore with a first reference connection contact 15A is connected, the first reference terminal contact 15A optionally with a first defined reference potential V _Ref1 or a second defined reference potential V _Ref2 can be applied.

In this exemplary embodiment of a sensor device according to the invention 100 is the sensor electrode E1 through their first electrode connection 17th , a section of the first connection line 11 , a second connection node 12th as well as another electrical line 16 and the first Schottky diode D1 with the associated reference connection contact 15A connected.

That first Schottky diode D1 is in such a way with the first reference connection contact 15A connected that it locks when this is connected to this reference connection contact 15A applied reference potential greater than the threshold voltage of this Schottky diode D1 is, and that it opens when that first reference connection contact 15A applied reference potential less than the threshold voltage of this Schottky diode D1 is. This can be compared to the electronic switching device 6th out 1 , discharging the sensor capacitance C _ex-1 the sensor electrode E1 being controlled.

To control the respective on the first reference connection contact 15A applied reference potential V _Ref1 or. V _Ref2 , is in this embodiment of a sensor device according to the invention 100 also an electronic switching device 6th provided, which is designed and set up to be switched between a first switching state and a second switching state, wherein when the electronic switching device 6th is in the first switching state, the first reference potential V _Ref1 at the first reference connection contact 15A so that the first Schottky diode D1 locks, and if the electronic switching device 6th is in the second switching state, the second reference potential V _Ref2 at the first reference connection contact 15A so that the first Schottky diode D1 opens.

In this case, the electronic switching device 6th in addition a control switching device S0 in the form of a MOSFET S0 on, the drain connection of which via a first section of a reference line 15th and another electrical resistor R0 , especially an ohmic resistor R0 , in the present case as a pull-up resistor R0 is used, with a first connection at which the first reference potential V _Ref1 is applied, which is + 5V in this example, is connected. The source connection of the MOSFET S0 is via a second section of the reference line 15th with a second connection at which the second reference potential V _Ref2 is applied, which in this example is a ground potential GND is connected.

The control switching device S0 , in this case the MOSFET S0 , in particular its gate connection, is via the second connection line 13th , which serves in particular as a control line, with the second connection contact 10 the control and evaluation device 8th connected, the control and evaluation device 8th designed and set up for this purpose, the control switching device S0 to switch between a first switching state and a second switching state, a switchover to the first switching state in which the MOSFET S0 blocks that on the first reference connection contact 15A the first reference potential V _Ref1 sets and switching to the second switching state, in which the MOSFET S0 in a through state, ie a conductive state, that is at the first reference connection contact 15A the second reference potential V _Ref2 adjusts.

This embodiment of a sensor device according to the invention 100 is also designed to carry out a method according to the invention, which will be described in more detail below, wherein the sensor device 100 , especially the control and evaluation device 8th , for this purpose is also designed and set up, in particular, on the first connection contact 9 to detect and evaluate a voltage, the control and evaluation device 8th in this exemplary embodiment has a switchable input and output for this purpose, in particular a GPIO connection contact 9 , which can be switched either as an input or output, what by the switch S1 should be symbolized, as well as an analog-to-digital converter ADC1 , which one with the first connection contact 9 is connectable.

1. a) Bereitstellen der Sensorvorrichtung 100,
2. b) Aufladen der ersten Referenzkapazität C_Ref-1 , indem jeweils ein definiertes Ladepotential an den zugehörigen ersten Anschlusskontakt 9 der Steuerungs- und Auswerteeinrichtung 8 angelegt wird, insbesondere mithilfe der Schalteinrichtung S1,
3. c) Entladen der mit der Umgebung gebildeten ersten Sensorkapazität C_ex-1 , der ersten Sensorelektrode E1, indem das zweite definiertes Referenzpotential V_Ref2 , welches in diesem Fall ein Massepotential GND ist, an den zugehörigen ersten Referenz-Anschlusskontakt 15A angelegt wird, welches bewirkt, dass die erste Schottky-Diode D1 öffnet, über welche die zugehörige Sensorelektrode E1 mit dem zugehörigen Referenz-Anschlusskontakt 15A elektrisch verbunden ist,
4. d) Herbeiführen eines Potentialausgleichs zwischen wenigstens der ersten Referenzkapazität C_Ref-1 und der ersten Sensorkapazität C_ex-1 der ersten Sensorelektrode E1, wobei dazu insbesondere der zugehörige erste Anschlusskontakt 9 der Steuerungs- und Auswerteeinrichtung 8 hochohmig geschaltet wird und das definierte erste Referenzpotential V_Ref1 , welches in diesem Fall +5V beträgt, an den ersten Referenz-Anschlusskontakt 15A angelegt wird, was bewirkt, dass die erste Schottky-Diode D1 sperrt,
5. e) Erfassen der an dem ersten Anschlusskontakt 9 der Steuerungs- und Auswerteeinrichtung 8, anliegenden Spannung mittels des ersten Analog-Digital-Konverters ADC1, und
6. f) Auswerten der erfassten Spannung.

To operate the in 2 pictured sensor device 100 according to a method according to the invention, the following steps are carried out:

1. a) Providing the sensor device 100 ,
2. b) Charging the first reference capacitance C _Ref-1 by adding a defined charging potential to the associated first connection contact 9 the control and evaluation device 8th is applied, in particular with the help of the switching device S1 ,
3. c) discharging the first sensor capacitance formed with the environment C _ex-1 , the first sensor electrode E1 by adding the second defined reference potential V _Ref2 , which in this case is a ground potential GND is to the associated first reference connection contact 15A which causes the first Schottky diode D1 opens over which the associated sensor electrode E1 with the associated reference connection contact 15A is electrically connected,
4. d) bringing about equipotential bonding between at least the first reference capacitance C _Ref-1 and the first sensor capacitance C _ex-1 the first sensor electrode E1 , with this in particular the associated first connection contact 9 the control and evaluation device 8th is switched to high resistance and the defined first reference potential V _Ref1 , which in this case is + 5V, to the first reference connection contact 15A is applied, which causes the first Schottky diode D1 locks
5. e) Detecting the at the first connection contact 9 the control and evaluation device 8th , applied voltage by means of the first analog-digital converter ADC1 , and
6. f) Evaluation of the recorded voltage.

For applying the defined reference potential V _Ref1 , V _Ref2 in steps c) and d) on the associated first reference connection contact 15A becomes the control switchgear S0 accordingly via the second connection contact 10 the control and evaluation device 8th and the second connection line 13th from the control and evaluation device 8th is controlled, whereby to apply the second reference potential V _Ref2 which causes the first Schottky diode D1 blocks and thus to bring about the equipotential bonding in step d), the control switching device S0 is switched to a first switching state or is held in this, and for applying the first reference potential V _Ref1 which causes the first Schottky diode D1 opens and thus for discharging the first sensor capacitance C _ex-1 the first sensor electrode E1 in step c), the control switching device S0 is switched to a second switching state or is held in this.

3 shows a block diagram of a second embodiment 200 a sensor device according to the invention 200 , in which the first sensor electrode E1 next to the first electrode connection 17th a second electrode connection 18th has over which the sensor electrode E1 in this case with the associated Schottky diode D1 and via this with the associated reference connection node 15A connected is. This enables a continuity test of the sensor electrode at least in sections E1 , in some cases a complete continuity test, depending on the design of the sensor electrode E1 , the sensor electrode E1 particularly preferred as in the 4a and 4b the DE 10 2019 129 802 is trained.

4th shows a diagram in which for an embodiment of a Schottky diode D1 , D2 , D3 , (see. 1 to 3 and 5 and 6th ) a profile of an internal, parasitic capacitance of the Schottky diode D1 , D2 , D3 depending on one at the Schottky diode D1 , D2 , D3 applied voltage is shown in order to make it clear that it is advantageous for a high measurement accuracy if at the time of the measurement in each case a voltage as high as possible on the Schottky diode D1 , D2 , D3 is applied in order to have the lowest possible parasitic capacitance that negatively affects the measurement accuracy.

5 shows a block diagram of a third exemplary embodiment of a capacitive sensor device according to the invention 300 , this sensor device 300 next to the first electric conductive sensor electrode E1 two further electrically conductive sensor electrodes E2 , E3 for the capacitive detection of the presence of an input means in a detection area of the sensor device 300 has, which also each have a further sensor capacitance with the environment C _ex-2 , C _ex-2 form, the sensor device 300 for each additional sensor electrode E2 , E3 furthermore in each case a further first, the respective further sensor electrode E2 , E3 assigned connection cable 11B , 11C , in each case a further, the respective further sensor electrode E2 , E3 assigned reference capacity C _Ref-2 , C _Ref-3 , and in each case a further first, the respective further sensor electrode E2 , E3 associated electrical resistance R2 , R3 having.

The control and evaluation device 8th also has for each additional sensor electrode E2 , E3 in each case a further first, the respective further sensor electrode E2 , E3 assigned connection contact 9B , 9C on and each additional sensor electrode E2 , E3 is via the associated, respective further first connection line 11B , 11C and via the associated, further first electrical resistance R2 , R3 ; R1B , R1C with the associated further first connection contact 9B , 9C the control and evaluation device 8th connected.

In each case, the ones for the other sensor electrodes E2 , E3 associated, further reference capacities C _Ref-2 , C _Ref-3 on the one hand, in each case between the associated, further first connection contact 9B , 9C and the associated, further first electrical resistor R2 , R3 with the associated, further first connection cable 11B , 11C connected and on the other hand with the base potential V _base .

Each of the other sensor electrodes E2 , E3 is also via another Schottky diode D2 , D3 with an associated reference connection contact 15B , 15C connected, with the individual reference connection contacts in this embodiment 15A , 15B and 15C each via a common reference line 15th are connected and each using a common electronic switching device 6th in each case simultaneously with the first reference potential V _Ref1 or the second reference potential V _Ref2 can be acted upon, whereby a particularly simple sensor device 300 can be provided, which enables a spatially resolved capacitive detection at the same time, in addition to each first connection contact 9A , 9B , 9C a separate analog-digital converter each ADC1 assigned.

6th shows a block diagram of a fourth embodiment of a capacitive sensor device according to the invention 400 , this sensor device 400 furthermore for each sensor electrode E1 , E2 , E3 a second electrical resistor associated therewith R2A , R2B , R2C has, which with that of the respective sensor electrode E1 , E2 , E3 associated first electrical resistance R1A , R1B , R1C is connected in series so that the sensor electrodes E1 , E2 , E3 in each case via the associated first connection line 11A , 11B , 11C , via the associated, first electrical resistance R1A , R1B , R1C and the associated second electrical resistance R2A , R2B , R2C with the associated first connection contact 9A , 9B , 9C the control and evaluation device 8th are connected.

The first electrical resistance R1A , R1B , R1C and the second electrical resistor R2A , R2B , R2C are selected in the present case in such a way that the first electrical resistance R1A , R1B , R1C is in each case at least ten times as large as the associated second electrical resistance R2A , R2B , R2C , in particular so that the condition C _Refx * R1x »C _ex-x * R2x is always fulfilled.

If steps b) and d) of a method according to the invention are carried out simultaneously, a switching state of the sensor device that is required for this is established 400 particularly preferably maintained at least for a time t1 = C _ex-x * R2x.

The switching state for bringing about the equipotential bonding in step d) is preferably maintained for at least a time t2 = C _Refx * (R1x + R2x) before the actual measurement is started.

This makes it possible to ensure in a simple manner that the reference capacitances are sufficiently charged C _Ref-1 , C _Ref-2 , C _Ref-3 , a sufficient discharge of the sensor capacities C _ex-1 , C _ex-2 , C _ex-3 and adequate equipotential bonding takes place.

Wird VRef2 = 0V, d.h. als GND gewählt, wie bei den beschriebenen Ausführungsbeispielen, ergibt sich: $${\text{C}}_{\text{ex}-\text{x}}={\text{C}}_{\text{Refx}}*\left({\text{V}}_{\text{Ref}1}-\text{Vx}\right)\text{/Vx},$$

und damit eine besonders einfache Ermittlung der jeweiligen kapazitiven Kopplung einer Sensorelektrode Ex mit der Umgebung.The following applies to the voltage Vx, which is recorded depending on the capacitive coupling of a sensor electrode Ex with the environment: $$\text{Vx}=\left({\text{C.}}_{\text{Refx}}*{\text{<figure-callout id="1" label="V Ref" filenames="DE102019135103A1\_0003.png,DE102019135103A1\_0004.png" state="{{state}}">V</figure-callout>}}_{\text{Ref}}+{\text{C.}}_{\text{ex}-\text{x}}*{\text{V}}_{\text{Ref}2}\right)\text{/}\left({\text{C.}}_{\text{Refx}}+{\text{C.}}_{\text{ex}-\text{x}}\right)$$

If VRef2 = 0V, ie as GND selected, as in the exemplary embodiments described, results in: $${\text{C.}}_{\text{ex}-\text{x}}={\text{C.}}_{\text{Refx}}*\left({\text{V}}_{\text{Ref}1}-\text{Vx}\right)\text{/ Vx},$$

and thus a particularly simple determination of the respective capacitive coupling of a sensor electrode Ex with the environment.

List of reference symbols

1

capacitive sensor device from the prior art

100, 200, 300, 400

capacitive sensor device according to the invention

3

Sensor electrode

4th

Sensor capacity (capacity of the sensor electrode with the environment)

5

Reference capacity

6th

electronic switchgear

7th

electrical resistance, especially pull-up resistance

8th

Control and evaluation device

9, 9A, 9B, 9C

first connection contact

10

second connection contact

11, 11A, 11B, 11C

first connection line (measuring line)

12, 12A, 12B, 12C

second connection node

13th

second connection line (control line)

14, 14A, 14B, 14C

first connection node

15th

Reference line

15A, 15B, 15C

Reference connection node

16, 16A, 16B, 16C

further connection cable

17th

first electrode connection

18th

second electrode connection

Cex-1, Cex-2, Cex-3

Sensor capacity (capacity of the first sensor electrode with the environment)

CRef-1, CRef-2, CRef-3

Reference capacity

ADC1, ADC2, ADC3

Analog-to-digital converter

D1, D2, D3

Schottky diode

E1, E2, E3

Sensor electrode

GND

Ground potential

R0

further electrical resistance (especially pull-up resistance)

R1, R2, R3,

first electrical resistance

R1A, R1B, R1C

R2A, R2B, R2C

second electrical resistance

S0

Control switching element

S1, S2, S3

Electronic switching device for controlling a GPIO output on the respective first connection contact

VBasis

Base potential

VRef1

first reference potential

VRef2

second reference potential

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 29924441 U1 [0003]
• US 9823798 B2 [0003, 0016]
• DE 102019128656 [0003, 0008, 0052, 0078]
• DE 102019129802 [0016, 0059, 0105]

Claims (15)

Capacitive sensor device (100, 200, 300, 400) for an operating device of a vehicle for detecting an approach and / or contact, comprising: - a first electrically conductive sensor electrode (E1) for capacitive detection of the presence of an input means in a detection area of the sensor device (100 _{, 200, 300, 400), the sensor electrode (E1) forming a sensor capacitance (C ex-1} ) which changes with the presence of an input means in the detection area of the sensor device (100, 200, 300, 400), - a control and evaluation device (8) with a first connection contact (9, 9A), - a first connection line (11, 11A), - a first reference _{capacitance (C Ref-1} ), - a first electrical resistor (R1, R1A), and - a with a defined reference _potential (V Ref1, V _Ref2 ) can be acted upon first reference connection contact (15A), the first sensor electrode (E1) via the first connection line (11, 11A) and via the first n electrical resistance (R1, R1A) is connected or can be connected to the first connection contact (9, 9A) of the control and evaluation device (8), and wherein the first reference capacitance (C _Ref-1 ) on the one hand between the first connection contact (9, 9A) and the first electrical resistor (R1, R1A) is connected or connectable to the first connection line (11, 11 A) and, on the other hand, is connected or connectable to a base potential (V _base ), characterized in that the sensor device (100, 200, 300, 400) furthermore has at least one first Schottky diode (D1), via which the first sensor electrode (E1) is also connected or can be connected to the first reference connection contact (15A), the first reference connection contact (15A) A first defined reference _potential (V Ref1) or a second defined reference _{potential (V Ref2) can optionally be} applied, the first reference _potential (V Ref1) being greater than the threshold voltage of the first Schottky diode (D1) and the first sensor electrode (E1) is connected or connectable to the first reference connection contact (15A) via the first Schottky diode (D1) in such a way that the first Schottky diode (D1) blocks when the first reference _potential (V Ref1) is applied to the first reference connection contact (15A), and wherein the second reference _potential (V Ref2) is less than the threshold voltage of the first Schottky diode (D1) and the first sensor electrode (E1) is via the first Schottky diode (D1) is connected or connectable to the first reference connection contact (15A) so that the first Schottky diode (D1) opens when the second reference _potential (V Ref2) is applied to the first reference connection contact (15A) . Sensor device (100, 200, 300, 400) according to Claim 1 , characterized in that the sensor device (100, 200, 300, 400) furthermore has an electronic switching device (6) which is designed and set up to be switched between a first switching state and a second switching state, wherein when the electronic Switching device (6) is in the first switching state, the first reference _potential (V Ref1) is applied to the first reference connection contact (15A) so that the first Schottky diode (D1) blocks, and when the electronic switching device (6) is in the second switching state , the second reference _potential (V Ref2) is applied to the first reference connection contact (15A), so that the first Schottky diode (D1) opens. Sensor device (100, 200, 300, 400) according to Claim 1 or 2 , characterized in that the electronic switching device (6) has a control switching device (S0) which can be switched from a first switching state to a second switching state, a switchover to the first switching state causing the first reference connection contact (15A _{) sets} the first reference potential (V Ref1) and switching to the second switching state causes the second reference _potential (V Ref2) to be set at the first reference connection contact (15A). Sensor device (100, 200, 300, 400) according to one of the preceding claims, characterized in that the sensor device (100, 200, 300, 400) furthermore has a first connection to which the first reference _potential (V Ref1) is applied, and a second connection to which the second reference _potential (V Ref2) is applied, wherein the first reference connection contact (15A) is or can be connected to the first connection and to the second connection, in particular via a reference line (15). Sensor device (100, 200, 300, 400) according to Claim 4 , characterized in that the sensor device (100, 200, 300, 400) has at least one further electrical resistor (R0), the first reference connection contact (15A) being connected or connectable to the first connection via this further electrical resistor (R0) is, in particular by means of the reference line (15). Sensor device (100, 200, 300, 400) according to Claim 3 and one of the Claims 4 or 5 , characterized in that the first reference connection contact (15A) is connected or can be connected to the second connection via the control switching device (S0), in particular by means of the reference line (15). Sensor device (100, 200, 300, 400) according to one of the Claims 3 to 6th , characterized in that the sensor device (100, 200, 300, 400) furthermore has a second connection line (13) and the control and evaluation device (8) furthermore has a second connection contact (10), the control switching device (S0) via the second connection line (13) is or can be connected to the second connection contact (10) of the control and evaluation device (8), and wherein the control and evaluation device (8) is designed and set up for this purpose, the control switching device (S0) at least to switch between a first switching state and a second switching state. Sensor device (100, 200, 300, 400) according to one of the Claims 3 to 7th , characterized in that the control switching device (S0) has or is a field effect transistor (S0). Sensor device (100, 200, 300, 400) according to Claim 8 , characterized in that the field effect transistor (S0) is a metal-oxide-semiconductor field effect transistor, the second connection contact (10) of the control and evaluation device (8) via the second connection line (13) in particular with the gate connection of the field effect transistor (S0) is connected or connectable. Sensor device (300, 400) according to one of the preceding claims, characterized in that the sensor device (300, 400) in addition to the first electrically conductive sensor electrode (E1) at least one further electrically conductive sensor electrode (E2, E3) for capacitive detection of the presence of an input means in a detection area of the sensor device (300, 400), which also forms a further sensor capacitance (C _ex-2 , C _ex-2 ) with the surroundings, the sensor device (300, 400) for each further sensor electrode (E2, E3 ), furthermore - a further first connection line (11B, 11C) assigned to the further sensor electrode (E2, E3), - a further reference capacitance (C _Ref-2 , C _Ref-3 ) assigned to the further sensor electrode (E2, E3), and - has a further first electrical resistor (R2, R3) assigned to the further sensor electrode (E2, E3), the control and evaluation device (8) for each further sensor electrode de (E2, E3), furthermore has a further first connection contact (9B, 9C) assigned to the further sensor electrode (E2, E3), at least one further sensor electrode (E2, E3) via the associated further first connection line (11B, 11C ) and via the associated, further first electrical resistor (R2, R3; R1B, R1C) is or can be connected to the associated further first connection contact (9B, 9C) of the control and evaluation device, the further reference _{capacitance (C Ref-2} , C Ref- ₃ ) on the one hand between the associated, further first connection contact (9B, 9C) and the associated, further first electrical resistor (R2, R3; R1B, R1C) is or can be connected to the associated, further first connection line (11B, 11C) and on the other hand is connected or connectable to one or the base potential (V _base). Sensor device (300, 400) according to Claim 10 , characterized in that the sensor device (300, 400) furthermore has at least one further Schottky diode (D2, D3) assigned to a further sensor electrode (E2, E3), the at least one further sensor electrode (E2, E3) via the associated , another Schottky diode (D2, D3) is connected or can be connected to a reference connection contact (15B, 15C), in particular an associated further reference connection contact (15B, 15C), the reference connection contact (15A, 15B, 15C ), in particular the respectively associated further reference connection contact (15B, 15C), can optionally be _{acted upon with a respective first defined reference potential} (V Ref1) or a respective second defined reference _potential (V Ref2), the respective first reference _potential (V Ref1) is greater than the threshold voltage of the associated, further Schottky diode (D2, D3), the respective second reference _potential (V Ref2) is less than the threshold voltage, and further e sensor electrode (E2, E3) in such a way via the associated, further Schottky diode (D2, D3) with the reference connection contact (15A, 15B, 15C), in particular with the respectively associated, further reference connection contact (15B, 15C), connected or connectable is that the associated, further Schottky diode (D1) blocks when the respective first reference _potential (V Ref1) is applied to the reference connection contact (15A, 15B, 15C), in particular to the respectively associated, further reference connection contact (15B, 15C), and opens when the respective second reference _potential (V Ref2) is applied to the reference connection contact (15A, 15B, 15C), in particular to the respective associated further reference connection contact (15B, 15C). Sensor device (300, 400) according to one of the preceding claims, characterized in that the sensor device (400) further comprises at least one of a sensor electrode (E1, E2, E3) assigned, second electrical resistor (R2A, R2B, R2C), which with the the first electrical resistor (R1A, R1B, R1C) assigned to the respective sensor electrode (E1, E2, E3) is connected in series so that the sensor electrode (E1, E2, E3) via the associated first connection line (11 A, 11B, 11C), via the associated first electrical resistor (R1A, R1B, R1C) and the associated second electrical resistor (R2A, R2B, R2C) with the associated first connection contact (9A , 9B, 9C) of the control and evaluation device (8) is connected or connectable, wherein the first electrical resistor (R1A, R1B, R1C) and the second electrical resistor (R2A, R2B, R2C) are selected such that the first electrical Resistance (R1A, R1B, R1C) is approximately at least ten times as large as the second electrical resistance (R2A, R2B, R2C). Sensor device (100, 300, 400) according to one of the preceding claims, characterized in that the first sensor electrode (E1) and / or at least one further sensor electrode (E2, E3) has a first electrode connection (17), at least one sensor electrode (E1 , E2, E3) via this first electrode connection (17) to the associated first connection line (11, 11A, 11B, 11C) and via this and via the associated first electrical resistor (R1, R2, R3; R1A, R1B, R1C) is connected or connectable to the associated first connection contact (9, 9A, 9B, 9C) of the control and evaluation device (8), and at least one sensor electrode (E1, E2, E3) also via this first electrode connection (17) and via the associated Schottky diode (D1, D2, D3) is connected or can be connected to the associated reference connection contact (15A). Method for operating a capacitive sensor device (100, 200, 300, 400) which, according to one of the Claims 1 to 13th is formed, characterized by the steps: g) providing a sensor device, which according to one of the Claims 1 to 13th h) charging at least one reference capacitance (C _Ref-1 , C _Ref-2 , C _Ref-3 ) by applying a defined charging potential to the associated first connection contact (9, 9A, 9B, 9C) of the control and evaluation device (8) is applied, i) discharging at least one sensor capacitance (C _ex-1 , C _ex-2 , C _ex-3 ) formed with the environment at least one sensor electrode (E1, E2, E3) by adding a defined reference _{potential (V Ref2} ) is applied to the associated reference connection contact (15A), which causes the respective Schottky diode (D1, D2, D3) to open, via which the associated sensor electrode (E1, E2, E3) with the associated reference connection contact ( 15A, 15B, 15C) is electrically connected or connectable, j) bringing about a potential equalization between at least one reference capacitance (C _Ref-1 , C _Ref-2 , C _Ref-3 ) and the associated sensor capacitance (C _ex-1, C _{ex- 2} , C _ex-3 ) of the associated sensor electrode (E1, E2, E3), with this in particular ere the associated first connection contact (9, 9A, 9B, 9C) of the control and evaluation device (8) is switched to high resistance and a defined reference _potential (V Ref1) is applied to the associated reference connection contact (15A, 15B, 15C), which causes the respective Schottky diode (D1, D2, D3) to block, via which the associated sensor electrode (E1, E2, E3) is electrically connected or can be connected to the associated reference connection contact (15A, 15B, 15C), k) Detecting at least one applied voltage at at least one first connection contact (9, 9A, 9B, 9C) of the control and evaluation device (8), and I) evaluating the detected voltage. Procedure according to Claim 14 , wherein the sensor device (100, 200, 300, 400) according to one of Claims 7 to 13th is designed, characterized in that to apply the defined reference _potential (V Ref1, V _Ref2 ) in step c) and d) on the associated reference connection contact (15A, 15B, 15C) the control switching device (S0) in each case correspondingly via the second Connection contact (10) of the control and evaluation device (8) and the second connection line (13) is controlled by the control and evaluation device (8), for applying a reference _potential (V Ref1), which causes the respective Schottky diode (D1, D2, D3) blocks, via which the associated sensor electrode (E1, E2, E3) is electrically connected or can be connected to the associated reference connection contact (15A, 15B, 15C), and thus to bring about potential equalization in step d) , the control switching device (S0) is switched to a first switching state or is held in this, and wherein for applying a reference _potential (V Ref2), which causes the respective Schottky diode e (D1, D2, D3) opens, via which the associated sensor electrode (E1, E2, E3) is electrically connected or can be connected to the associated reference connection contact (15A, 15B, 15C) and thus at least one formed with the environment for discharging Sensor capacitance (C _ex-1 , C _ex-2 , C _ex-3 ) of at least one sensor electrode (E1, E2, E3) in step c), the control switching device (S0) is switched to a second switching state or is held in this .

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