Sensor and sensor analysis method

Abstract

The invention relates to a sensor having two power supply interfaces, four measurement paths and two analysis circuits, the measurement paths having anisotropic magnetoresistive components and being connected in total four half-bridges, so that both pole crossing points and rotational directions can be identified and functional safety is achieved. The invention further relates to an associated sensor analysis method.

Description

Technical Field

[0001] The invention relates to a sensor and a related sensor analysis method. Background Art

[0002] The sensor is used, for example, to determine the movement of a pole wheel or a linear device. The pole wheel can be used, for example, to measure the rotation of a wheel. Typically, the pole wheel is mounted in such a way that it rotates at the same speed and in the same direction as the wheel. If the speed of rotation of the pole wheel or a signal indicating this speed and / or the direction of rotation is measured with the aid of a sensor, information about the rotation of the wheel can be obtained. The method can be used, for example, to determine the rotation speed and direction of the wheel. This allows conclusions to be drawn, for example, about the speed of the motor vehicle or whether intervention in the driving stability system is necessary. Summary of the invention

[0003] The object of the present invention is to provide a sensor which replaces the known design or has a better design than the known design. Another object of the present invention is to provide a related method. According to the present invention, this can be achieved by the sensor and the method described in the respective main claims. Advantageous design solutions can be obtained, for example, from the respective subclaims. The contents of the claims become the description content by explicit reference.

[0004] The present invention relates to a sensor. The sensor has a first power supply interface and a second power supply interface. The sensor has a first measurement path with a first measurement interface. The sensor has a second measurement path with a second measurement interface. The sensor has a third measurement path with a third measurement interface. The sensor has a fourth measurement path with a fourth measurement interface. The sensor has a first analysis circuit and a second analysis circuit. All measurement paths are connected between the first power supply interface and the second power supply interface. Each measurement path has at least one upper impedance device / resistance element connected between the first power supply interface and the measurement interface. Each measurement path has at least one lower impedance device connected between the measurement interface and the second power supply interface. The impedance device is in particular an anisotropic magnetoresistive device. Typically, the magnetic orientation of the upper impedance device of each measurement path is different from the magnetic orientation of the lower impedance device. Observed along the x-axis of the sensor, the second measurement path and the third measurement path are arranged between the first measurement path and the fourth measurement path. The impedance device extends in particular along the y-axis of the sensor. The first analysis circuit is connected to the first measurement interface and the fourth measurement interface. The second analysis circuit is connected to the second measurement interface and the third measurement interface.

[0005] With the aid of such sensors, the movement of the magnetic pole wheel can be detected in an advantageous manner, wherein both the rotational speed and the direction of rotation can be detected. The claimed embodiment has proven to be particularly robust. In this case, two evaluation circuits can be used in an especially advantageous manner, wherein one evaluation circuit, in particular the first evaluation circuit, can be used to determine the direction of rotation and the other evaluation circuit can be used to determine the rotational speed. The data obtained by the two evaluation circuits can also be compared with one another.

[0006] In this case, a sensor is particularly a sensor which detects the movement of a pole wheel. A pole wheel is in principle a wheel which has a series of magnets with different poles and which generates a structured magnetic field in the surroundings which can be detected in particular by means of a sensor. Typically, the pole wheel moves along the aforementioned x-axis. Instead of a pole wheel, a linear device can also be used. Typically, a linear device also has a series of magnets with different poles. The pole wheel can also be formed by a gear-like configuration. In this case, there can be, in particular, protruding teeth, which in particular deflect the magnetic field lines of a permanent magnet arranged on the sensor to varying degrees. Such structures with protruding teeth can also be used for linear devices.

[0007] The power supply interface may in particular be an interface for supplying a current or a voltage to the sensor. The second power supply interface may in particular be a ground interface. The first power supply interface may in particular be an interface for a positive supply voltage or a negative supply voltage. The first power supply interface may also be divided into two parts in order to provide different supply voltages for different measurement paths, for example to implement a function in which only some measurement paths are actually used, while other measurement paths are not provided with a supply voltage, so that they are in a disabled state. This will be discussed in detail below.

[0008] Typically, the measuring path is a current path which, as described above, extends between two power supply connections and has at least one upper impedance component and at least one lower impedance component, between which a measuring interface is arranged. The measuring interface does not have to be directly visible on the sensor, but should be located at a position along the conductor at which the voltage can be tapped. There can also be any number of such positions between the two impedance components. For example, connection pads can be provided for the measuring interface.

[0009] Typically, the evaluation circuit is suitable for generating an output variable from two input variables. In this case, the evaluation circuit can be, in particular, a differential amplifier or an operational amplifier. In particular, an output signal in the form of a voltage or current can be generated from the voltage difference at two measuring connections. The output signal can then be further processed in a suitable manner.

[0010] The terms "upper impedance device" and "lower impedance device" are used only to distinguish two different impedance devices from the language. They refer to a typical design, in which the upper impedance device is arranged above the lower impedance device when looking down on the sensor in a vertically oriented paper plane, at least when the respective measuring paths are not kinked. However, the spatial orientation of the upper and lower impedance devices can be arbitrary, depending on the spatial orientation of the sensor. Anisotropic magnetoresistive materials have, in particular, their own magnetic orientation. If the external magnetic field is parallel to this magnetic orientation, the anisotropic magnetoresistive material has a particularly low or particularly high impedance. If the external magnetic field is perpendicular to the magnetic orientation, the impedance changes significantly compared to an external magnetic field orientation parallel to the magnetic orientation. This can be used for the detection of magnetic fields. By using impedance devices with different magnetic orientations, the influence of external magnetic fields can be detected in a particularly beneficial way. For example, a certain external magnetic field can lead to a reduction in the impedance of the upper impedance device, while the impedance of the lower impedance device increases at the same time. The effect is thereby increased and the signal to be measured becomes more pronounced.

[0011] The x-axis is an axis that can define the sensor in a suitable manner. For example, it can extend horizontally in a vertical paper plane when looking down on the sensor. Typically, the y-axis extends transversely to the x-axis, preferably completely perpendicular thereto. In a vertical paper plane when looking down on the sensor, it typically extends vertically upwards. The x-axis and y-axis are used here only to express geometrical relationships in the sensor. Typically, the x-axis and y-axis are not incorporated into the sensor and can be defined in a suitable manner in order to check whether the sensor complies with the claimed embodiment. The x-axis also defines the x-direction and the y-axis also defines the y-direction.

[0012] In particular, it can be pre-set that the second measurement path and the third measurement path cross at a position between the upper impedance device and the lower impedance device. This can be understood in particular from an electrical and / or geometric point of view. In particular, the crossing of the currents does not necessarily mean that the two conductor lines overlap at one point, as seen along the x-axis. As will be described in detail below, this also means that a suitable wiring scheme is selected so that the currents can cross even if there are no intersections between the conductor lines. By the crossing of the measurement paths, the influence of the magnetic field on the second and third measurement paths is balanced. In particular, the degree of coverage of the second measurement path or the third measurement path by the acting magnetic field is of little or no importance. This influence should be as independent of the specific position as possible.

[0013] In particular, it can be provided that the upper impedance element of the second measurement path has a magnetic orientation different from the upper impedance element of the third measurement path and / or transverse to the upper impedance element of the third measurement path. In particular, it can be provided that the lower impedance element of the second measurement path has a magnetic orientation different from the lower impedance element of the third measurement path and / or transverse to the lower impedance element of the third measurement path. In particular, it can be achieved that the magnetic field effects acting on the second and third measurement paths are reversed on the measurement paths, so that the voltage difference between the second measurement interface and the third measurement interface increases. In this way, the signal quality can be improved.

[0014] The upper impedance device of the second measurement path and the lower impedance device of the third measurement path can be arranged in particular along a collinear line or along a collinear line parallel to the y-axis. The upper impedance device of the third measurement path and the lower impedance device of the second measurement path can be arranged in particular along a collinear line or along a collinear line parallel to the y-axis. The intersection of the measurement paths can be achieved by such an arrangement. Here, the magnetic component parallel to the y-axis can reach the impedance device of the second measurement path and the impedance device of the third measurement path. Such a design can be understood in particular as the intersection of two measurement paths. The impedance device can extend in particular along each corresponding longitudinal direction, wherein, typically, the impedance device is longer when viewed along the longitudinal direction than when viewed transversely to the longitudinal direction. The impedance device can be arranged in particular as a flat device, for example a rectangular device on the periphery. Correspondingly, the longitudinal axis can be defined along the maximum extension direction of the impedance device parallel to the side. The impedance device can be understood in particular as a two-dimensional structure.

[0015] Arranging the two impedance components along a common axis means in particular that the two impedance components have the same extension when viewed transversely to the axis. Therefore, the outer edges of the two impedance components can also be located on a common axis.

[0016] According to one design solution, the first measurement path may have a first upper impedance device and a second upper impedance device connected in series therewith. According to one design solution, the first measurement path may have a first lower impedance device and a second lower impedance device connected in series therewith. According to one design solution, the fourth measurement path may have a first upper impedance device and a second upper impedance device connected in series therewith. According to one design solution, the fourth measurement path may have a first lower impedance device and a second lower impedance device connected in series therewith. The two impedance devices just mentioned may in particular each be connected to the other device as an impedance device. By using two impedance devices, a spacing can be generated between the impedance devices, thereby obtaining a higher resolution than by using only one impedance device. In addition, when using the above-mentioned two impedance devices, a very beneficial geometric arrangement can also be achieved, which will be discussed in more detail below.

[0017] The first upper impedance device and the second upper impedance device of the first measurement path may in particular be arranged along a collinear line, or along a collinear line parallel to the y-axis. The first lower impedance device and the second lower impedance device of the first measurement path may in particular be arranged along a collinear line, or along a collinear line parallel to the y-axis. The first upper impedance device and the second upper impedance device of the fourth measurement path may in particular be arranged along a collinear line, or along a collinear line parallel to the y-axis. The first lower impedance device and the second lower impedance device of the fourth measurement path may in particular be arranged along a collinear line, or along a collinear line parallel to the y-axis. This allows for a simple design, which has proven to have significant advantages in terms of sensitivity.

[0018] The first upper impedance device of the first measurement path, the first lower impedance device of the first measurement path, the upper impedance device of the second measurement path, the upper impedance device of the third measurement path, the first upper impedance device of the fourth measurement path, and the first lower impedance device of the fourth measurement path can be arranged in a line, or in a line parallel to the x-axis. The second upper impedance device of the first measurement path, the second lower impedance device of the first measurement path, the lower impedance device of the third measurement path, the lower impedance device of the second measurement path, the second upper impedance device of the fourth measurement path, and the second lower impedance device of the fourth measurement path can be arranged in a line, or in a line parallel to the x-axis. Reference can be made to the design scheme for the y-axis mentioned above. However, unlike the y-axis, the extension length of the impedance device along the x-axis is typically shorter, wherein, in the case of being arranged in a line as described herein, the impedance device is arranged, for example, so that the short side of the rectangle is typically parallel to the x-axis.

[0019] The sensor may have a center point or a center line in particular. The center line may be, for example, perpendicular to the x-axis and / or parallel to the y-axis. The center point may, for example, be located on the center line. The center line may have and / or be defined by the following properties in particular.

[0020] It can be preset that the second measuring path and the third measuring path have the same distance from the center point or the center line along the x-axis. It can be preset that the first measuring path and the fourth measuring path have the same distance from the center point or the center line along the x-axis. In this way, a symmetrical arrangement with respect to the center point or the center line can be achieved. In particular, it can be preset that the second measuring path and the third measuring path are designed closer to each other than the first measuring path and the fourth measuring path.

[0021] In particular, it can be provided that the second measuring path and the third measuring path are arranged in the range of at most 300 micrometers or at most 400 micrometers along the x-axis. Such a small distance has proven to be advantageous, since the exact position of the magnetic field lines intersecting the at least one measuring path is irrelevant, so that the magnetic field has essentially the same influence on the second and third measuring path.

[0022] The first measuring path and the second measuring path have a spacing of at least 500 micrometers and / or at most 700 micrometers from one another along the x-axis. The third measuring path and the fourth measuring path have a spacing of at least 500 micrometers and / or at most 700 micrometers from one another along the x-axis. Such spacing has proven to be advantageous. However, other spacings may also be used depending on the magnetic pole wheel used.

[0023] The distance can be measured, for example, between the center points of the measuring paths or between the complete outer edges of the respective measuring paths. This can prevent, in particular, mutual interference of the measuring paths or magnetic field lines from affecting too many measuring paths at the same time.

[0024] The magnetic orientation of some or all upper impedance devices of the same measurement path may be orthogonal to the magnetic orientation of some or all lower impedance devices. This may, for example, involve each corresponding impedance device in the considered measurement path. It may also involve more considered impedance devices, in particular all considered impedance devices.

[0025] In particular, it can be provided that the magnetic orientation of some or all impedance elements is at an angle of at least 40° and / or at most 50°, or 45° to the y-axis. This enables the magnetic orientation of the impedance elements under consideration to be arranged uniformly.

[0026] Part or all of the impedance elements can be extended / elongated in particular. The central axes can extend in particular along the y-axis. A longitudinally extended design can be understood in particular as a rectangular design, in which two opposite sides are significantly longer than the other two sides. The two opposite sides can in particular be at least 10%, at least 200%, at least 300%, at least 500% or at least 1000% longer than the other sides. The central axis can in particular be the axis of symmetry of the respective impedance element.

[0027] According to an advantageous design, the first power connection can be divided into a first part and a second part. The first part can be switched in particular independently of the second part. In particular, it can be pre-set that the first measuring path and the fourth measuring path can be connected to the first part. In particular, it can be pre-set that the second measuring path and the third measuring path can be connected to the second part. As a result, the measuring path responsible for identifying the rotation can be switched independently of the measuring path responsible for identifying the direction of rotation. As a result, energy can be saved, for example, by selectively switching off the corresponding measuring paths. This will be discussed in more detail below with reference to the method described herein.

[0028] In particular, it can be pre-set that in the second measurement path and / or the third measurement path, the upper impedance component has an upper interface in the y direction, which is connected to a connection line connected to the upper interface of the lower impedance component in the y direction, wherein the measurement interface is located in the connection line. Here, the concept of the lower interface and / or the upper interface is viewed in the y-axis direction, wherein a zero point can be defined, from which the y direction extends along the y-axis. In a top view of the sensor and a vertical paper plane, the y direction can be shown as vertically upward, for example. Correspondingly, even if the sensor may have other orientations in space, the concept of the lower interface or the upper interface can be clearly assigned. It is sufficient to have the configuration described in at least one possible orientation. Through this type of design, the intersection of the second measurement path and the third measurement path can be achieved in a beneficial way without the actual physical intersection of the conductor lines. This avoids the use of another conductive layer to establish the intersection.

[0029] In particular, it can be provided that in the second measurement path and / or the third measurement path, the upper impedance component has a lower interface connected to the power supply interface in the y direction. In particular, it can be provided that in the second measurement path and / or the third measurement path, the lower impedance component has a lower interface connected to the power supply interface in the y direction. This also enables an advantageous design of the interface of such impedance components without requiring a further layer when the measurement paths intersect.

[0030] The x-axis can intersect the y-axis orthogonally or transversely in particular. This can be an angle of 90° in particular. However, angles slightly deviating from this, such as ±1°, 2° or 5°, can also be used.

[0031] The first evaluation circuit can be a differential amplifier in particular. The second evaluation circuit can be a differential amplifier in particular. Such a differential amplifier can generate an output signal, such as a voltage or a current, in particular, which depends on the difference between two input voltage signals, for example is proportional to the difference. These input voltage signals are the voltages at the respective connected measuring interfaces. This allows a direct evaluation of the output signal with respect to the rotational speed in the rotational direction.

[0032] It is particularly advantageous if the impedance element occupies the entire space or at least a major part of the entire space, viewed in the y-direction. The impedance element may in particular completely or at least a major part of the extension of the pole wheel in the y-direction, for example at least 90%.

[0033] In the sensor described here, it can be provided in particular that a support magnet is present which generates a support magnetic field. Typically, this support magnetic field is superimposed on a magnetic field generated by a magnetic pole wheel or another unit to be measured.

[0034] The present invention also relates to a method for analyzing a sensor, in particular a method for analyzing the sensor described herein. The method comprises the following steps:

[0035] - reading out a first output signal of the first analysis circuit and / or a second output signal of the second analysis circuit,

[0036] - identifying a zero crossing point in one of the output signals, and

[0037] - In response thereto, a pole crossing point is identified.

[0038] Such methods can advantageously analyze the sensor to determine the movement of adjacent pole wheels. A pole crossing point means in particular that one pole or two poles have passed the sensor. Typically, the poles on the pole wheels alternate in such a way that a pole is always followed by a pole of opposite magnetization. Typically, only two poles are present on a pole wheel. With regard to the sensors used, reference can be made to all the embodiments described herein and their variants.

[0039] The pole crossing point can be determined in particular independently of the direction of rotation using the first output signal. The second output signal or its amplitude and / or its sign, in particular the second output signal at the same point in time or its amplitude and / or its sign, can then be used to determine the direction of rotation. However, the reverse method steps can also be used. Typically, a zero crossing point of one of the output signals indicates that the magnetic pole wheel has continued to rotate by a certain angle value, so that the sign of one of the output signals has changed.

[0040] It is to be understood that in the case of use of a possible offset, the corresponding method steps, i.e. the identification of not the zero crossing point but the mean value of the signal passing through a certain value, in particular different from zero, are considered equivalent. The offset or mean value can be calculated, for example, as a function of an upper and a lower limit of the signal, for example as the arithmetic mean between these two values. The upper and lower limits can, for example, delimit the actual measured signal or also a range of values. The offset or mean value can also be determined by an area integration of the measured signal.

[0041] In particular, it can be provided that, in the case of a zero crossing of an output signal, the direction of rotation is identified based on the sign of the further output signal. Thus, the sign of the further output signal is used to determine the direction of rotation, while the zero crossing is used to identify the pole crossing. This can be achieved in principle by the first output signal being used to identify the sign and the second output signal being used to identify the zero crossing, or vice versa.

[0042] In particular, it can be pre-set that in response to a fault condition or a request, the power supply to the first and fourth measuring paths or the power supply to the second and third measuring paths is switched off. Energy can be saved in this way, for example, because the direction of rotation does not usually change for a long time when the vehicle is moving forward in normal operation, so that there is no need to repeatedly re-identify the direction of rotation. In this way, both measuring paths can be switched off without losing critical information. Such a request can, for example, come from a vehicle control system that recognizes that the vehicle is moving forward in normal operation. Fault states can be detected by different units of the motor vehicle. For example, inconsistencies in generated output data or generated output signals can be detected. In this case, some of the measuring paths can be switched off, in particular those measuring paths for which a functional fault is expected. Functional safety can be significantly increased in this way, because the sensor function can still be performed even in the event of a fault in one or both measuring paths.

[0043] In particular, zero crossings of the two output signals can be determined. In particular, a pole crossing determined with the aid of the first output signal can be compared with a pole crossing determined with the aid of the second output signal. This can, for example, mean that a fault is detected if pole crossings detected with the aid of different output signals are spaced apart from one another by more than an absolute or relative threshold value, or if the difference between the repetition rates of pole crossings detected with the aid of different output signals exceeds an absolute or relative threshold value.

[0044] If three zero crossings of an output signal are detected within a defined period of time, a common zero crossing can be formed from these three zero crossings before further processing steps. In particular, it can be achieved that, in the case where, due to certain fluctuations in the output signal, a pole crossing leads not only to one zero crossing, but to three zero crossings in succession, these zero crossings can be further processed correctly. Such a triple zero crossing can mean, in particular, that the excitation magnetic field is too strong or that the pole spacing of the pole wheel is too large in relation to the sensor specifications. However, by using the common zero crossing described herein, further analysis can be performed in such cases as if only one zero crossing had been detected initially.

[0045] Furthermore, to achieve the switching of the measuring path, in particular, the first measuring path can be divided into two parts according to the sensor embodiment described above. Alternatively, the second measuring path can also be divided into two parts.

[0046] According to one embodiment, it can be provided that a zero crossing is detected if the output signal crosses a predetermined value or an average value of the signal. The predetermined value can be stored permanently, in particular for a longer period of time, for example.

[0047] For example, the average value can be

[0048] - determined by the upper and lower limits of the signal,

[0049] - determined by the upper / peak and lower extremes of the signal, and / or

[0050] - is determined to be a valid value of the signal.

[0051] Typically, the upper and lower limits of a signal define the range of values ​​that the signal actually occupies within a specific time period. The upper and lower limits typically define the range that the signal can occupy in principle. The effective value can be determined, for example, by integrating the area of ​​the signal within a predetermined time period.

[0052] The invention also relates to a control device configured to perform the method described herein. Furthermore, the invention also relates to a sensor comprising such a control device. Furthermore, the invention also relates to a non-volatile computer-readable storage medium having a program code stored thereon, which, when executed, causes a processor to perform the method described herein. With respect to the method described herein, all embodiments described herein and their variants may be used accordingly.

[0053] The invention also relates to a sensor arrangement with a sensor as described herein and a pole wheel or a linear element with a plurality of poles. The sensor can be arranged relative to the pole wheel or the linear element in particular in such a way that the sensor can sense a movement of the pole wheel or the linear element. With regard to the sensor, all the designs described herein and their variants can be used.

[0054] The configuration described here is based in particular on a total of four half-bridges. These half-bridges are arranged differently around a central point. Typically, different types of impedance components are present in each measurement path in order to amplify the respective signal.

[0055] As described above as an advantageous embodiment, the distances from the first measuring path and the fourth measuring path to the center point are identical or at least substantially identical, which in particular allows the occurrence of zero crossings of the generated output signal to be extremely reliable. Typically, the output signal is processed without an offset, but it can also be processed with an offset. Such an offset can occur, for example, when using strong magnetic fields.

[0056] The design described here has a particularly good functional safety. The signal that is typically used to detect the direction of rotation can also be used for pulse detection or identification. In this case, another signal that is originally used for pulse detection can also be used to detect the direction of rotation. This allows a functional cross-check. During a fault, for example, the current consumption is reduced in order to signal a fault state. As described above, this can be achieved in particular by disabling two measuring paths. However, the function of detecting the pole crossing point is still maintained.

[0057] In particular, a disturbance field can be detected in response to a deviation of the mean value of the second output signal from the zero point by at least a predetermined value. This can be forwarded, for example, as a fault message to other components and / or as a fault state for controlling the sensor. In this case, the mean value can be calculated, for example, over a predetermined number of measured values ​​or over a predetermined time period.

[0058] In particular, a fault state, in particular a fault state in which the excitation magnetic field is too strong and / or the pole spacing is too large, can be identified in response to the identification of three zero crossing points in the first output signal within a predetermined time period. Such a fault state is also called a triple fault (Triplet). It indicates the above-mentioned fault cause. It can be forwarded to other components as a fault report and / or used as a fault state for controlling sensors, for example. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Professionals will learn more about the features and advantages of the embodiments described in the following drawings.

[0060] Figure 1 : This is the sensor according to the first embodiment,

[0061] Figure 2 : This is the sensor according to the second embodiment, and

[0062] Figure 3 : This is the output signal curve. DETAILED DESCRIPTION

[0063] Figure 1 The sensor 50 according to the first embodiment of the invention is shown purely schematically. The sensor 50 has a first power supply connection Vcc and a second power supply connection Vss. The second power supply connection Vss is here a ground connection. The first power supply connection Vcc provides a positive or negative power supply voltage compared to ground.

[0064] The sensor 50 has a first measurement path 100, a second measurement path 200, a third measurement path 300 and a fourth measurement path 400. As shown in the figure, the measurement paths 100, 200, 300 and 400 are respectively connected between two power supply interfaces Vcc and Vss, so that the necessary operating voltage can be provided to them in an appropriate manner.

[0065] The x-axis and y-axis are defined in the sensor 50. This is shown according to the coordinate system in the lower left corner. Here, the x-axis is Figure 1 The y-axis is in the horizontal direction of the paper plane. Figure 1 The vertical direction in the plane of the paper, with the two axes perpendicular to each other. A pole wheel or linear device not shown in the figure typically moves in the x-axis direction.

[0066] As shown in the figure, the second measurement path 200 and the third measurement path 300 are disposed between the first measurement path 100 and the fourth measurement path 400 as viewed along the x-axis.

[0067] The measurement paths 100, 200, 300 and 400 have multiple impedance devices. These impedance devices will be described below. As shown in the figure, the top view of the impedance device is rectangular. Here, the long sides are parallel to each other. Similarly, the short sides are also parallel to each other. The short sides extend along the x-axis. The long sides extend along the y-axis. The impedance device is composed of anisotropic magnetoresistive material. This type of anisotropic magnetoresistive material each has a magnetic orientation. The magnetic orientation of each impedance device is shown in the figure. Here, part of the magnetic orientation is set at an angle of 45° to the y-axis and has a gradient from the lower left to the upper right; part of the magnetic orientation is set at an angle of 45° to the y-axis and has a gradient from the upper left to the lower right. The magnetic orientation shown in the figure represents a preferred design. In principle, each measurement path 100, 200, 300, 400 has two types of magnetically oriented impedance devices. These impedance devices are connected in series in principle to enhance the anisotropic magnetoresistive effect.

[0068] The first measurement path 100 has a first measurement interface 130. The second measurement path 200 has a second measurement interface 230. The third measurement path 300 has a third measurement interface 330. The fourth measurement path 400 has a fourth measurement interface 430. The impedance device connected between the first power supply interface Vcc and each corresponding measurement interface 130, 230, 330, 430 is called an upper impedance device. The impedance device connected between each corresponding measurement interface 130, 230, 330, 430 and the second power supply interface Vss is called a lower impedance device. This is only used for semantic distinction, basically referring to Figure 1 However, this does not represent the actual orientation in the sensor 50 when the sensor 50 is arbitrarily oriented in space, because the sensor 50 can be arbitrarily oriented in space in principle.

[0069] The first measurement path 100 has a first upper impedance device 111 and a second upper impedance device 112. In addition, the first measurement path also has a first lower impedance device 121 and a second lower impedance device 122. Correspondingly, the fourth measurement path 400 has a first upper impedance device 411, a second upper impedance device 412, a first lower impedance device 421 and a second lower impedance device 422. Therefore, each has two lower impedance devices and two upper impedance devices, thereby improving the overall effect. In addition, more uniform induction can be achieved along the y-axis, that is, the strength of the influence of the acting magnetic field along the y-axis is not so important.

[0070] The second measurement path 200 has an upper impedance component 210 and a lower impedance component 220. The third measurement path 300 has an upper impedance component 310 and a lower impedance component 320. The two upper impedance components 210 and 310 are arranged as mirror images in terms of magnetic orientation. The same applies to the two lower impedance components 320, 220. As shown in the figure, the second measurement path 200 and the third measurement path 300 intersect each other, so that when viewed from the y direction, the lower impedance component 320 of the third measurement path 300 is below the upper impedance component 210 of the second measurement path 200, and when viewed from the y direction, the lower impedance component 220 of the second measurement path 200 is below the upper impedance component 310 of the third measurement path 300.

[0071] As shown in the figure, the first upper impedance device 111 of the first measurement path 100, the first lower impedance device 121 of the first measurement path 100, the upper impedance device 210 of the second measurement path 200, the upper impedance device 310 of the third measurement path 300, the first upper impedance device 411 of the fourth measurement path 400, and the first lower impedance device 421 of the fourth measurement path 400 are arranged at the same height. This applies to both the upper short sides of the above-mentioned corresponding impedance devices and the lower short sides of the corresponding impedance devices. The same applies to other impedance devices, that is, the second upper impedance device 112 of the first measurement path 100, the second lower impedance device 122 of the first measurement path 100, the lower impedance device 320 of the third measurement path 300, the lower impedance device 220 of the second measurement path 200, the second upper impedance device 412 of the fourth measurement path 400, and the second lower impedance device 422 of the fourth measurement path 400.

[0072] The spacing between the second measuring path 200 and the third measuring path 300 should be as small as possible. Here, with the center line 60 as a reference, the spacings a2 and a3 of the second measuring path 200 and the third measuring path 300 from the center line are respectively about 130 microns. The spacing a1 between the first measuring path 100 and the second measuring path 200 and the spacing a4 between the fourth measuring path 400 and the third measuring path 300 are respectively about 660 microns. Such dimensions have proven to be very useful for typical applications. As shown in the figure, the spacings are each referenced to the center point of each corresponding measuring path 100, 200, 300, 400 observed from the x direction.

[0073] The sensor 50 has a first analysis circuit AW1 and a second analysis circuit AW2. They are configured as differential amplifiers. They each have a positive input terminal (+) and a negative input terminal (-). Their respective output signals indicate the difference between the two input signals. As shown in the figure, the first analysis circuit AW1 is connected to the first measurement interface 130 and the fourth measurement interface 430. Therefore, the output signal of the first analysis circuit AW1 is proportional to the voltage difference on the two measurement interfaces 130 and 430. Here, the two outer measurement paths, namely the first measurement path 100 and the fourth measurement path 400, can be used to identify the rotation direction of the magnetic pole wheel moving near the sensor 50, typically in the x direction.

[0074] The second analysis circuit AW2 is connected to the second measurement interface 230 and the third measurement interface 330. Therefore, the voltage difference between the two measurement interfaces 230 and 330 can be determined and further analyzed. If the output signal has a zero crossing point, it typically indicates that a pole crossing point has occurred in the magnetic pole wheel.

[0075] Figure 2 A sensor 50 according to a second embodiment is shown. Here, the impedance device is arranged with Figure 1 The designs shown are identical, but the connections are different. In particular, respective soldering pads are provided for the measuring interfaces 130, 230, 330 and 430. These soldering pads can be contacted in particular by means of soldering wires. A soldering pad is also provided for the second power supply interface Vss. Figure 1 The design shown is different, and the first power supply interface Vcc is divided into two parts. There is a first part Vcc1, which supplies power to the first measurement path 100 and the fourth measurement path 400. In addition, there is a second part Vcc2, which supplies power to the second measurement path 200 and the third measurement path 300. Here, the two parts Vcc1 and Vcc2 are not electrically connected to each other. However, a gap is preset at the separation point 70, which is in principle suitable for connecting the two parts Vcc1 and Vcc2 to each other through the continuation of the electrical connection. The two parts Vcc1 and Vcc2 of the first power supply interface Vcc also have corresponding pads for welding.

[0076] As shown in the figure, the wiring method of the line is that the two impedance components 220, 320 arranged below in the y direction of the second measurement path 200 and the third measurement path 300 are contacted from above, wherein the connection is made with the respective upper side of the other impedance component 210, 310. By such mutual connection, the above-mentioned electrical crossover can be realized without further connection levels. This significantly simplifies the production of the sensor.

[0077] like Figure 2 As shown, when viewed from the x direction, the pad of the second power interface Vss is located at the center, thereby achieving a symmetrical grounding interface.

[0078] Figure 3 The output signal curves of the evaluation circuits AW1 and AW2 are shown. These signal curves are essentially sinusoidal, which represent an ideal shape. The analysis is based on the step of determining the zero crossing points of the output signal of the second evaluation circuit AW2, optionally in the form of a common zero crossing point of the output signals. This indicates that a pole crossing point has occurred, i.e. the pole wheel has continued to rotate by a certain angle. The direction of rotation can then be inferred from the sign of the output signal of the first evaluation circuit AW1 here. Depending on whether the sign there is negative or positive, the pole wheel rotates in one direction or the other.

[0079] As an alternative, zero crossings can also be determined in the output signal of the first evaluation circuit AW1, optionally in the form of a common zero crossing, and the direction of rotation can be determined from the sign of the output signal of the second evaluation circuit AW2.

[0080] If a malfunction occurs or energy conservation is required, especially according to Figure 2 In the embodiment shown, some of the measuring paths can be switched off, for example, in order to signal a fault state. For example, the first measuring path 100 and the fourth measuring path 400 can be switched off by grounding the first part Vcc1 of the first power supply connection Vcc. In this case, only the second measuring path 200 and the third measuring path 300 remain in operation. The pole crossing points of the magnetic pole wheel can still be determined based on the zero crossing points of the determined output signal. Although the direction of rotation can no longer be determined here, this is typically not necessary if the vehicle only drives forward during normal operation. Before reversing, the vehicle must first be parked, which can be detected, and then, for example, the sensor 50 can resume operation of all measuring paths 100, 200, 300, 400.

[0081] To meet further requirements in terms of functional safety, for example, a strong homogeneous magnetic offset can be detected. In addition, it is possible to detect whether the excitation signal is too strong or whether the pole pitch of the magnetic pole wheel is too large.

[0082] The steps of the method according to the invention can be carried out in the order specified. However, they can also be carried out in another order if technically feasible. The method according to the invention can be carried out in one of the embodiments, for example, with a specific combination of steps, so that other steps are no longer carried out. However, in principle, more steps can also be carried out, including those not mentioned.

[0083] It should be noted that in the claims and description, for example, for ease of understanding, features may be described in combination, although they can also be used separately. A person skilled in the art will recognize that these features can also be used independently with other features or in combination with other features.

[0084] The references in the dependent claims may characterize preferred combinations of the respective features, but do not exclude other combinations of features.

[0085] Reference numerals list

[0086] 50 Sensors

[0087] 60 Centerline

[0088] 70 separation point

[0089] 100 First measurement path

[0090] 111 First upper impedance device

[0091] 112 second upper impedance device

[0092] 121 First Lower Impedance Device

[0093] 122 Second lower impedance device

[0094] 130 First measurement interface

[0095] 200 Second measurement path

[0096] 210 Upper impedance device

[0097] 220 Low impedance device

[0098] 230 Second measurement interface

[0099] 300 Third measurement path

[0100] 310 Upper impedance device

[0101] 320 Low Impedance Device

[0102] 330 Third measurement interface

[0103] 400 Fourth measurement path

[0104] 411 First Upper Impedance Device

[0105] 412 second upper impedance device

[0106] 421 First Lower Impedance Device

[0107] 422 second lower impedance device

[0108] Vcc first power supply interface

[0109] Vcc1 Part 1

[0110] Vcc2 Part 2

[0111] Vss Second power supply interface

[0112] AW1 First analysis circuit

[0113] AW2 Second analysis circuit

[0114] a Spacing

Claims

1. A sensor (50), comprising: - a first power supply interface (Vcc), - Second power supply interface (Vss), a first measuring path (100) having a first measuring interface (130), a second measuring path (200) with a second measuring interface (230), a third measuring path (300) with a third measuring interface (330), a fourth measuring path (400) with a fourth measuring interface (430), - a first analyzing circuit (AW1), and - a second analysis circuit (AW2), -in, All measurement paths (100, 200, 300, 400) are connected between a first power supply interface (Vcc) and a second power supply interface (Vss). - wherein each measurement path (100, 200, 300, 400) has at least one upper impedance device (111, 112, 210, 310, 411, 412), and the upper impedance device is connected between the first power supply interface (Vcc) and the measurement interface (130, 230, 330, 430), - wherein each measurement path (100, 200, 300, 400) has at least one lower impedance device (121, 122, 220, 320, 421, 422), and the lower impedance device is connected between the measurement interface (130, 230, 330, 430) and the second power supply interface (Vss), - wherein the impedance devices (111, 112, 121, 122, 210, 220, 310, 320, 411, 412, 421, 422) are anisotropic magnetoresistive devices, - wherein the magnetic orientation of the upper impedance device (111, 112, 210, 310, 411, 412) of each measurement path (100, 200, 300, 400) is different from the magnetic orientation of the lower impedance device (121, 122, 220, 320, 421, 422), wherein the second measurement path (200) and the third measurement path (300) are located between the first measurement path (100) and the fourth measurement path (400) when viewed along the x-axis of the sensor (50), - wherein the impedance device (111, 112, 121, 122, 210, 220, 310, 320, 411, 412, 421, 422) extends along the y-axis of the sensor (50), - wherein the first analysis circuit (AW1) is connected to the first measurement interface (130) and the fourth measurement interface (430), and - wherein the second evaluation circuit (AW2) is connected to the second measurement interface (230) and the third measurement interface (330).

2. The sensor (50) according to claim 1, - wherein the second measurement path (200) and the third measurement path (300) intersect at respective locations between the upper impedance device (210, 310) and the lower impedance device (220, 320).

3. A sensor (50) according to any one of the preceding claims, wherein the magnetic orientation of the upper impedance component (210) of the second measurement path (200) is different from the magnetic orientation of the upper impedance component (310) of the third measurement path (300) and / or is oriented transversely to the magnetic orientation of the upper impedance component (310) of the third measurement path (300), and / or -in, The magnetic orientation of the lower impedance component (220) of the second measurement path (200) is different from and / or oriented transversely to the magnetic orientation of the lower impedance component (320) of the third measurement path (300).

4. A sensor (50) according to any one of the preceding claims, - wherein the upper impedance device (210) of the second measurement path (200) and the lower impedance device (320) of the third measurement path (300) are arranged along a collinear line or along a collinear line parallel to the y-axis, and / or -in, The upper impedance device (310) of the third measurement path (300) and the lower impedance device (220) of the second measurement path (200) are arranged along a collinear line or along a collinear line parallel to the y-axis.

5. A sensor (50) according to any one of the preceding claims, - wherein the first measurement path (100) comprises a first upper impedance device (111) and a second upper impedance device (112) connected in series with the first upper impedance device, and / or -in, The first measurement path (100) comprises a first lower impedance device (121) and a second lower impedance device (122) connected in series with the first lower impedance device. and / or - wherein the fourth measurement path (400) comprises a first upper impedance device (411) and a second upper impedance device (412) connected in series with the first upper impedance device, and / or - wherein the fourth measurement path (400) comprises a first lower impedance device (421) and a second lower impedance device (422) connected in series with the first lower impedance device.

6. The sensor (50) according to claim 5, - wherein the first upper impedance device (111) and the second upper impedance device (112) of the first measurement path (100) are arranged along a collinear line or along a collinear line parallel to the y-axis, and / or -in, The first lower impedance device (121) and the second lower impedance device (122) of the first measurement path (100) are arranged along a collinear line or along a collinear line parallel to the y-axis. and / or - wherein the first upper impedance device (411) and the second upper impedance device (412) of the fourth measurement path (400) are arranged along a collinear line or along a collinear line parallel to the y-axis, and / or - wherein the first lower impedance device (421) and the second lower impedance device (422) of the fourth measurement path (400) are arranged along a collinear line or along a collinear line parallel to the y-axis.

7. The sensor (50) according to any one of claims 5 to 6, - wherein a first upper impedance device (111) of the first measurement path (100), a first lower impedance device (121) of the first measurement path (100), The upper impedance device (210) of the second measurement path (200), the upper impedance device (310) of the third measurement path (300), the first upper impedance device (411) of the fourth measurement path (400) and the first lower impedance device (421) of the fourth measurement path (400) are arranged on a line, or on a line parallel to the x-axis, and / or -in, a second upper impedance device (112) of the first measurement path (100), a second lower impedance device (122) of the first measurement path (100), The lower impedance device (320) of the third measurement path (300), the lower impedance device (220) of the second measurement path (200), the second upper impedance device (412) of the fourth measurement path (400) and the second lower impedance device (422) of the fourth measurement path (400) are arranged on a line, or on a line parallel to the x-axis.

8. A sensor (50) according to any one of the preceding claims, - wherein the sensor (50) has a center point or center line (60), -in, Along the x-axis, the distance between the second measurement path (200) and the center point or center line (60) is the same as the distance between the third measurement path (300) and the center point or center line, and / or -in, Along the x-axis, the first measurement path (100) is at the same distance from the center point or center line (60) as the fourth measurement path (400) is from the center point or center line.

9. A sensor (50) according to any one of the preceding claims, wherein the second measuring path (200) and the third measuring path (300) are arranged along the x-axis in the range of a maximum of 300 micrometers or a maximum of 400 micrometers.

10. The sensor (50) according to any one of the preceding claims, wherein the first measuring path (100) and the second measuring path (200) are spaced apart from one another along the x-axis by at least 500 micrometers and / or at most 700 micrometers, and / or -in, The third measuring path (300) and the fourth measuring path (400) are spaced apart from one another along the x-axis by at least 500 micrometers and / or at most 700 micrometers.

11. A sensor (50) according to any one of the preceding claims, - wherein the magnetic orientation of some or all upper impedance components (111, 112, 210, 310, 411, 412) of the same measurement path (100, 200, 300, 400) is orthogonal to the magnetic orientation of some or all lower impedance components (121, 122, 220, 320, 421, 422).

12. A sensor (50) according to any one of the preceding claims, - wherein the magnetic orientation of some or all of the impedance components (111, 112, 121, 122, 210, 220, 310, 320, 411, 412, 421, 422) is at an angle of at least 40° and / or at most 50° or 45° to the y-axis.

13. A sensor (50) according to any one of the preceding claims, - wherein some or all of the impedance components (111, 112, 121, 122, 210, 220, 310, 320, 411, 412, 421, 422) extend longitudinally, with respective central axes extending along the y-axis.

14. A sensor (50) according to any one of the preceding claims, -in, The first power supply interface (Vcc) is divided into a first part (Vcc1) and a second part (Vcc2), - wherein the first part (Vcc1) is switchable independently of the second part (Vcc2), - wherein the first measurement path (100) and the fourth measurement path (400) are connected to the first portion (Vcc1), and - wherein the second measurement path (200) and the third measurement path (300) are connected to the second portion (Vcc2).

15. A sensor (50) according to any one of the preceding claims, -in, In the second measurement path (200) and / or the third measurement path (300), the upper impedance component (210, 310) has an upper interface in the y direction, which is connected to a connection line connected to the upper interface of the lower impedance component (220, 320) in the y direction, wherein the measurement interface (230, 330) is located in the connection line.

16. A sensor (50) according to any one of the preceding claims, -in, In the second measurement path (200) and / or the third measurement path (300), the upper impedance device (210, 310) has a lower interface in the y direction, and the lower interface is connected to the power supply interface (Vcc, Vss). and / or - wherein, in the second measurement path (200) and / or the third measurement path (300), the lower impedance device (220, 320) has a lower interface in the y direction, and the lower interface is connected to the power supply interface (Vcc, Vss).

17. A sensor (50) according to any one of the preceding claims, wherein: The x-axis is orthogonal to the y-axis.

18. A sensor (50) according to any one of the preceding claims, - wherein the first analysis circuit (AW1) is a differential amplifier, and / or -in, The second analyzing circuit (AW2) is a differential amplifier.

19. Method for analyzing a sensor (50) according to any of the preceding claims, wherein: The method comprises the following steps: - reading out a first output signal of the first analysis circuit (AW1) and / or a second output signal of the second analysis circuit (AW2), - identifying a zero crossing point in one of the output signals, and - In response thereto, a pole crossing point is identified.

20. The method according to claim 19, wherein, at a zero crossing of one output signal, the direction of rotation is identified based on the sign of the other output signal.

21. A method according to any one of claims 19 or 20, - wherein, in response to a fault condition or a request: - shutting down the power supply of the first measurement path (100) and the fourth measurement path (400), or - Switching off the power supply to the second measurement path (200) and the third measurement path (300).

22. A method according to any one of claims 19 to 21, - wherein the zero crossing points of the two output signals are determined, and -in, The pole crossing point determined with the aid of the first output signal and the pole crossing point determined with the aid of the second output signal are compared with one another.

23. A method according to any one of claims 19 to 22, - wherein, if three zero crossings of an output signal are detected within a predetermined period of time, a common zero crossing is formed from these three zero crossings before a further processing step.

24. A method according to any one of claims 19 to 23, wherein a disturbing field is detected in response to a deviation of the average value of the second output signal from zero by at least a predetermined value within a predetermined period of time.

25. A method according to any one of claims 19 to 24, -in, In response to identifying three zero crossing points in the first output signal within a predetermined time period, a fault state of excessive excitation magnetic field and / or excessive pole pitch is identified.

26. A method according to any one of claims 19 to 25, - wherein a zero crossing is identified if the output signal crosses a predetermined value or a signal average value, - Among them, the average - determined by the upper and lower limits of the signal, - determined by the upper and lower extremes of the signal, and / or - is determined to be a valid value of the signal.

Images