Magnetic sensor apparatus and method for operating a magnetic sensor apparatus

Abstract

The present invention relates to a magnetic sensor apparatus comprising at least one measurement bridge (10) having magnetoresistive elements (R1 to R4), at least one line component (18), by supplying current to which a magnetic field that varies a particular orientation of a polarity (12) of the free layers can be induced, and an operating device (20) by means of which, when the magnetic sensor apparatus is in a constant orientation mode into which the magnetic sensor apparatus can be transferred and / or in which the magnetic sensor apparatus can be held by supplying direct current to the at least one line component (18), a first differential voltage value between two positions of the measurement bridge (10) can be ascertained and / or, when the magnetic sensor apparatus is in an alternating orientation mode into which the magnetic sensor apparatus can be transferred and / or in which the magnetic sensor apparatus can be held by supplying alternating current to the at least one line component (18), a second differential voltage value between the two positions of the measurement bridge (10) can be ascertained, wherein additionally at least an amount of a difference between the second differential voltage value and the first differential voltage value can be ascertained by means of the operating device (20), and an offset value and / or a desired mode of the magnetic sensor apparatus can be determined by the operating device (20) using at least the ascertained amount.

Description

[0001] R. 414747

[0002] - 1 -

[0003] Description

[0004] title

[0005] Magnetic sensor device and method for operating a magnetic sensor device

[0006] The present invention relates to a magnetic sensor device. The present invention also relates to a method for operating a magnetic sensor device.

[0007] State of the art

[0008] Prior art, such as “SET / RESET FUNCTION FOR MAGNETIC SENSORS” (Honeywell, SENSOR PRODUCTS, APPLICATION NOTE, AN213, Solid State Electronics Center, www.magneticsensors.com, (800) 323-8295, Page 1 - Page 8), provides for so-called SET / RESET functions by which a magnetic field is induced by energizing at least one conductor component, by means of which an orientation of the polarities of the free positions of magnetoresistive elements of at least one measuring bridge of a conventional magnetic sensor is varied.

[0009] Disclosure of the invention

[0010] The present invention provides a magnetic sensor device with the features of claim 1 and a method for operating a magnetic sensor device with the features of claim 10. R. 414747

[0011] - 2 -

[0012] Advantages of the invention

[0013] The present invention provides magnetic sensor devices by means of which the conventional problem of thermo-mechanical stress, which in the prior art often leads to measurement inaccuracies and / or erroneous measurements, can be compensated for by the advantageous operability of the respective magnetic sensor device. In particular, the present invention ensures that even if a magnetic sensor device according to the invention has only a single measuring bridge with magnetoresistive elements, reliable measurements are still possible with the respective magnetic sensor device without the occurrence of thermomechanical stress leading to measurement inaccuracies or erroneous measurements.The present invention thus provides an advantageous way to compensate for the thermo-mechanical stress occurring in a magnetic sensor device according to the invention, without the need to equip the respective magnetic sensor device with an additional measuring bridge, additional magnetoresistive elements, or other sensor elements. The present invention therefore enables the creation of a comparatively cost-effective magnetic sensor device that requires relatively little installation space and, despite the thermomechanical stress occurring within it, allows for reliable measurements with high accuracy and a low error rate. Since a magnetic sensor device according to the invention does not require complex sensor elements, its manufacturing process is simplified and its robustness is increased.Furthermore, the present invention facilitates the miniaturization of magnetic sensor devices, thereby also expanding the applicability of magnetic sensor devices.

[0014] As will become clear from the following description, the present invention implements an operating strategy for magnetic sensor devices which significantly reduces their energy consumption during operation. R. 414747

[0015] - 3 -

[0016] This also contributes to cost savings for a user of a magnetic sensor device according to the invention. Furthermore, the reduced energy consumption of magnetic sensor devices according to the invention facilitates their use in mobile devices.

[0017] In an advantageous embodiment of the magnetic sensor device, the operator unit is additionally designed and / or programmed such that, if the specified amount of the difference between the second differential voltage value minus the first differential voltage value is greater than the product of the second differential voltage value and a predetermined factor, the alternating alignment mode can be set as the target mode. The embodiment of the magnetic sensor device described here thus has an operator unit that specifically recognizes when, due to thermomechanical stress in the magnetic sensor device, the alternating alignment mode is preferable to the constant alignment mode, despite its generally higher energy consumption.This ensures that the thermo-mechanical stress occurring in the magnetic sensor device does not lead to measurement inaccuracies or incorrect measurements of the magnetic sensor device.

[0018] As an advantageous further development, the operator device can additionally be designed and / or programmed such that, by means of the operator device, if at least one temperature measured near and / or in the magnetic sensor device is above a respective predetermined temperature threshold, at least one temporal change of the measured temperature is above a respective predetermined temperature change threshold, a temperature difference between at least two simultaneously measured temperatures is above a respective predetermined temperature difference threshold, and / or a system interacting with the magnetic sensor device outputs a change-alignment mode request signal, which R. 414747

[0019] - 4 -

[0020] The reversible orientation mode can be set as the target mode. Using the options listed here, the operator device of the described embodiment of the magnetic sensor device can also advantageously react to a thermo-mechanical stress in the magnetic sensor device that is highly likely to occur, so that measurement inaccuracies or errors of the magnetic sensor devices are (almost) unlikely.

[0021] Preferably, the operator device is additionally designed and / or programmed such that the constant alignment mode can only be set as the target mode by means of the operator device if at least the specified amount of the difference between the second

[0022] The differential voltage value minus the first differential voltage value is less than the magnitude of the product of the second differential voltage value and the specified factor. The operator unit of the described embodiment of the magnetic sensor device can thus specifically detect when the constant alignment mode can be used instead of the alternating alignment mode to reduce the energy consumption of the magnetic sensor device.

[0023] In a further advantageous embodiment of the magnetic sensor device, the operator unit is additionally designed and / or programmed such that the offset value can be set by means of the operator unit to be equal to the difference between the second differential voltage value minus the first differential voltage value. The offset value set in this way advantageously contributes to "filtering out" the influence of the thermomechanical stress in the magnetic sensor device on the measurement results of the magnetic sensor device, without the need to determine the thermomechanical stress by complex measurements to set the offset value. The embodiment of the magnetic sensor device described here thus exhibits improved sensing accuracy, while nevertheless maintaining its R. 414747

[0024] - 5 -

[0025] The operator unit can be designed as relatively simple electronics that require little installation space.

[0026] Advantageously, the operator device is additionally designed and / or programmed such that, after setting the offset value, taking into account at least the specified amount of the difference between the second differential voltage value and the first differential voltage value, a measured value can be determined by the operator device in at least one subsequent measurement of the magnetic sensor device operating in constant alignment mode, taking into account the difference between a newly measured first differential voltage value and the specified offset value. This results in an "automatic filtering out" of the influence of thermo-mechanical stress in the magnetic sensor device on the measurements performed using the magnetic sensor device operating in constant alignment mode.

[0027] Advantageously, the operator device can additionally be designed and / or programmed such that, after a predetermined maximum time has elapsed since the last setting of the offset value, after a predetermined maximum number of measurements with the previously set offset value, and / or if at least one temperature measured near and / or in the magnetic sensor device exceeds a predetermined temperature threshold, at least one change in the measured temperature over time exceeds a predetermined temperature change threshold, a temperature difference between at least two simultaneously measured temperatures exceeds a predetermined temperature difference threshold, and / or a system interacting with the magnetic sensor device outputs a calibration request signal, the offset value can be reset by means of the operator device.In the embodiment of the magnetic sensor device described here, it is thus ensured that the operator's equipment is (essentially) always alerted in a timely manner to changes in the thermo-mechanical R. 414747.

[0028] - 6 -

[0029] Stresses in the magnetic sensor device are addressed by setting a new / adjusted offset value.

[0030] Preferably, the magnetic sensor device can be switched to and / or maintained in its constant orientation mode by means of only a single current pulse with a duration of 500 ns or less. It is also advantageous if the magnetic sensor device can be switched to and / or maintained in its alternating orientation mode by means of only two opposing current pulses, each with a duration of 500 ns or less. Such short current pulses as (sufficient) current supply advantageously contribute to reducing the energy consumption of the embodiment of the magnetic sensor device described herein.

[0031] For example, the magnetoresistive elements of the measuring bridge can be at least one TMR element, at least one GMR element, and / or at least one AMR element. This allows a variety of different magnetoresistive elements to be used for the embodiment of the magnetic sensor device described here.

[0032] The advantages described above are also achieved by carrying out a corresponding method for operating a magnetic sensor device. It is expressly noted that the method for operating a magnetic sensor device can be further developed according to the embodiments of the magnetic sensor device described above.

[0033] Brief description of the drawings

[0034] Further features and advantages of the present invention are explained below with reference to the figures. Figure 414747 shows: R. 414747

[0035] Figs. 1a to 1c show schematic representations and a coordinate system to explain a first embodiment of the magnetic sensor device;

[0036] Figs. 2a to 2c are schematic representations and a coordinate system to explain a second embodiment of the magnetic sensor device;

[0037] Fig. 3 is a flowchart to explain a first

[0038] Embodiment of the method for operating a magnetic sensor device; and

[0039] Fig. 4 is a flowchart to explain a second

[0040] Embodiment of the method for operating a magnetic sensor device.

[0041] Embodiments of the invention

[0042] Figures 1a to 1c show schematic representations and a coordinate system to explain a first embodiment of the magnetic sensor device.

[0043] The magnetic sensor device shown schematically in Figures 1a and 1b has at least one measuring bridge 10 with magnetoresistive elements R1 to R4. A supply voltage Vcc and a ground 10a are connected to the measuring bridge 10. The magnetoresistive elements R1 to R4 of the measuring bridge 10 can, for example, be at least one TMR element (Tunnel Magnetoresistance), at least one GMR element (Giant Magnetoresistance), and / or at least one AMR element (Anisotropic Magnetoresistance). R. 414747

[0044] - 8 - include. If at least one TMR element and / or at least one GMR element is used as magnetoresistive elements R1 to R4 of the measuring bridge 10, the magnetoresistive elements R1 to R4 each have a free layer in which the respective orientation of their polarity 12 is influenced / varied by a magnetic field prevailing at the respective magnetoresistive element R1 to R4, and each have a reference layer in which the respective orientation of their polarity 14 is fixed, e.g. by so-called laser annealing. The magnetic sensor device of Fig. 1 is shown only as an example.1a to 1c, provided that no magnetic field prevails at the magnetoresistive elements R1 to R4, the polarities 12 of the free positions of all magnetoresistive elements R1 to R4 of the measuring bridge 10 are aligned in the same spatial direction with respect to which the polarities 14 of the reference positions of all magnetoresistive elements R1 to R4 of the measuring bridge 10 are perpendicularly oriented, wherein the polarities 14 of the reference positions of the magnetoresistive elements R1 and R3 are opposite to the polarities 14 of the reference positions of the magnetoresistive elements R2 and R4.

[0045] The respective resistance values ​​R1 to R4 of the magnetoresistive elements R1 to R4 depend on the orientation of the polarity 12 of their free position relative to the polarity 14 of their reference position. This can be used to measure the magnetic field prevailing at the magnetoresistive elements R1 to R4 of the measuring bridge 10. However, thermo-mechanical stress 16 also influences the resistance values ​​R1 to R4 of the magnetoresistive elements R1 to R4.

[0046] The magnetic sensor device therefore has, in addition to the measuring bridge 10, at least one conductor component 18, by means of which an energizing magnetic field influencing / varying the orientation of the polarities 12 of the free positions of the magnetoresistive elements R1 to R4 can be induced. The at least one conductor component 18 can be, for example, at least one conductor and / or at least one coil. Furthermore, the R. 414747

[0047] - 9 -

[0048] Magnetic sensor device, an operator device 20, by means of whose design and / or programming the influence of the thermo-mechanical stress 16 on measurements performed by the magnetic sensor device can be significantly reduced

[0049] Due to the design and / or programming of its operator unit 20, the magnetic sensor device can be operated in either a first operating mode or a second operating mode. The first operating mode of the magnetic sensor device is hereinafter referred to as the constant alignment mode, while the second operating mode is described as the alternating alignment mode.

[0050] Figure 1a schematically depicts the constant alignment mode. Due to the design and / or programming of the operator unit 20, the magnetic sensor device can be switched to and / or maintained in the constant alignment mode by supplying (exclusively) direct current to the at least one conductor component 18. Preferably, only one current pulse 22 is sufficient to switch the magnetic sensor device to or maintain its constant alignment mode. The respective current pulse 22 preferably has a duration of less than or equal to 500 ns (nanoseconds), in particular less than or equal to 350 ns (nanoseconds), and especially less than or equal to 200 ns (nanoseconds). The current pulse 22, which is conducted through the at least one conductor component 18, induces a magnetic field that influences the respective polarity 12 of the free positions of the magnetoresistive elements R1 to R4.As a rule, the aforementioned current pulse 22 is not required for each measurement to hold the magnetic sensor device, but, for example, only for every nth measurement or in the event of other occurrences, such as, in particular, a start of the magnetic sensor device, a change of its operating mode, an exceedance of a measuring range of the magnetic sensor device, or at the request of a user of the magnetic sensor device. R. 414747.

[0051] - 10 -

[0052] The operator device 20 is additionally designed and / or programmed such that, when the magnetic sensor device is in its constant alignment mode, a first differential voltage value VMI between two positions of the measuring bridge 10 can be determined, which is defined according to equation (GL 1) with:

[0053] (Eq. 1) VMI = V+(22) - V.(22), where V+(22) and V-(22) are the voltages tapped at the measuring bridge when the magnetic sensor device is in its constant alignment mode.

[0054] As shown in equations (Eq. 2) to (Eq. 5), the resistance values ​​R1 to R4 of the magnetoresistive elements R1 to R4 of the magnetic sensor device in its constant orientation mode are defined by an inertial resistance Ro, a change in resistance AR caused by the magnetic field prevailing at the respective magnetoresistive element R1 to R4 mag and through a change in resistance caused by thermo-mechanical stress 16 ARstress:

[0055] (Eq. 2) R1 = Ro — ARmag " ARstress,

[0056] (Eq. 3) R2 = Ro + ARmag + ARstress,

[0057] (Eq. 4) R3 = Ro — ARmag ■ ARstress,

[0058] (Eq. 5) R2 = Ro + ARmag + ARstress,

[0059] Fig. 1b schematically depicts the so-called alternating alignment mode. Due to the design and / or programming of the operator device 20, the magnetic sensor device can be energized (only) with alternating current by supplying the at least one line component 18 to the R. 414747

[0060] - 11 -

[0061] The alternating orientation mode is transferred and / or maintained. This can be understood to mean that the current supply to the at least one line component 18 (exclusively) for transferring / maintaining the magnetic sensor device in its alternating orientation mode comprises two opposing current pulses 24a and 24b. Preferably, each of the two opposing current pulses 24a and 24b has a duration of less than or equal to 500 ns (nanoseconds), in particular less than or equal to 350 ns (nanoseconds), and especially less than or equal to 200 ns (nanoseconds).

[0062] The operator device 20 is additionally designed and / or programmed such that, while the magnetic sensor device is in its alternating alignment mode, a second differential voltage value VM2 between the two positions of the measuring bridge 10 can be determined, which is defined according to equation (Eq. 6) with:

[0063] (Eq. 6) V M2 = 1 A(V + (24a) - V-(24a) + V + (24b) - V-(24b)), where V+(24a), V-(24a), V+(24b) and V-(24b) are the voltages tapped at the measuring bridge of the magnetic sensor device in its alternating alignment mode.

[0064] This can also be described by stating that the magnetic sensor device operates in its alternating orientation mode in the so-called "magnetic chopping mode". This causes a rotation of the polarities 12 of the free positions of the magnetoresistive elements R1 to R4 and, accordingly, the resistances R1 to R4 of the magnetoresistive elements R1 to R4 as given by equations (GL 7) to (GL 10):

[0065] (Eq. 7) R1 - Ro ARmag,

[0066] (Eq. 8) R2 = Ro + ARmag, R. 414747

[0067] - 12 -

[0068] (Eq. 9) R3 - Ro ARmag,

[0069] (Eq. 10) R2 = Ro + ARmag,

[0070] It can be seen from equations (Eq. 7) to (Eq. 10) that the change in resistance AR caused by the thermo-mechanical stress 16 s t reThe second differential voltage value VM2 is (almost) completely compensated for in alternating alignment mode. The thermo-mechanical stress 16 present in the magnetic sensor device is thus related to at least a magnitude of a difference A between the second differential voltage value VM2 minus the first differential voltage value VMI, where the difference A is defined according to equation (Eq. 11) with:

[0071] (Eq. 11) A = V M2 - VMI

[0072] In the coordinate system of Fig. 1c, the abscissa indicates a mechanical strain p (in micrometers per meter), while the ordinate indicates a resulting magnetic flux density B (in 10'). 6Tesla). The data determined in constant orientation mode are plotted in the coordinate system using a graph gMi, while another graph gM2 is used for the data of the alternating orientation mode. It can be seen from the coordinate system of Fig. 1c that when the magnetic sensor device is in alternating orientation mode, the thermo-mechanical stress represented by the mechanical strain p has significantly less influence on the data than in constant orientation mode. However, operating the magnetic sensor device in constant orientation mode exhibits significantly reduced energy consumption compared to operating it in alternating orientation mode. R. 414747

[0073] - 13 -

[0074] In order to significantly minimize the influence of the thermo-mechanical stress 16 on measurements of the magnetic sensor device and at the same time ensure a comparatively low energy consumption of the magnetic sensor device, the operator device 20 is designed and / or programmed in such a way that at least the amount of the difference A between the second differential voltage value VM2 minus the first differential voltage value VMI can be determined / is determined by means of the operator device.Subsequently, by means of the operator device 20, taking into account at least the determined amount of the difference A between the second differential voltage value VM2 minus the first differential voltage value VMI, an offset value X for at least one measurement of the magnetic sensor device in the constant alignment mode and / or a target mode of the magnetic sensor device for at least one measurement from a set comprising the constant alignment mode and the alternating alignment mode can be determined / determined.

[0075] At least the magnitude of the difference A between the second differential voltage value VM2 minus the first differential voltage value VMI can thus be advantageously used as a "switching criterion" for switching between the constant alignment mode and the alternating alignment mode. By using the magnitude of the difference A as a "switching criterion" for selecting the target mode of the magnetic sensor device, it can be ensured that (essentially) the operating mode for the magnetic sensor device is always selected which is most advantageous with regard to the thermo-mechanical stress 16 occurring therein and with regard to a desired low energy consumption of the magnetic sensor device.

[0076] Preferably, the operator device 20 is designed and / or programmed such that, by means of the operator device 20, if the determined amount of the difference A between the second differential voltage value VM2 minus the first differential voltage value VMI is greater than an amount of a product R. 414747

[0077] - 14 - of the second differential voltage value VM2 multiplied by a predefined factor n, the alternating alignment mode can be / is defined as the target mode. The factor n can be chosen by the manufacturer of the magnetic sensor device or by a user of the magnetic sensor device. Thus, if the relation (R. 1) applies, the constant alignment mode is switched to the alternating alignment mode:

[0078] (R. 1) IA | > | n * VM2 I

[0079] The alternating alignment mode is thus executed precisely when, due to the comparatively high thermo-mechanical stress 16 in the magnetic sensor device, compensating for the stress's influence on the measurement of the magnetic sensor device is advantageous despite the higher energy consumption. In contrast, if relation (R. 2) holds, the system switches from alternating alignment mode to constant alignment mode.

[0080] (R. 2) | A | < | n * V M2 1

[0081] This allows the more energy-efficient constant alignment mode to be specifically executed when the thermo-mechanical stress 16 in the magnetic sensor device is (essentially) negligible.

[0082] As an additional feature, the selection of the target mode can (optionally) also be made dependent on whether at least one temperature measured near and / or in the magnetic sensor device exceeds a predefined temperature threshold, whether at least one change in the measured temperature over time exceeds a predefined temperature change threshold, whether a temperature difference between at least two simultaneously measured temperatures exceeds a predefined temperature difference threshold, and / or whether a condition is met according to R. 414747.

[0083] - 15 -

[0084] The magnetic sensor device and the interacting system output a change-orientation mode request signal. In particular, by equipping the magnetic sensor device and / or its immediate surroundings with multiple temperature sensors, at least two temperatures can be measured simultaneously near and / or in the magnetic sensor device. For example, the change-orientation mode is then selected as the target mode by means of the operator device 20, provided that the relation (R.1) applies if at least one temperature measured near and / or in the magnetic sensor device exceeds the respective specified temperature threshold, at least one time-dependent change in the measured temperature exceeds the respective specified temperature change threshold, the temperature difference between at least two simultaneously measured temperatures exceeds the respective specified temperature difference threshold, and / or the system interacting with the magnetic sensor device outputs the change-alignment mode request signal. Accordingly, the design and / or programming of the operator device 20 can also ensure that the constant alignment mode is determined as the target mode, provided the relation (R.2) applies if at least one temperature measured near and / or in the magnetic sensor device is below the respective specified temperature threshold, at least one time-dependent change of the measured temperature is below the respective specified temperature change threshold, the temperature difference between at least two simultaneously measured temperatures is below the respective specified temperature difference threshold, and / or the system interacting with the magnetic sensor device does not output a change-alignment mode request signal.

[0085] Alternatively or additionally to the "switching criterion", the offset value X, determined taking into account at least the magnitude of the difference A between the second differential voltage value VM2 minus the first differential voltage value VMI, can also be advantageously used. For example, the operator device 20 can be designed and / or programmed to set the offset value X equal to the difference A between the second differential voltage value VM2 and the first differential voltage value VMI. R. 414747

[0086] - 16 - minus the first differential voltage value VMI according to equation (GL 12) to be determined with:

[0087] (GL 12) X = A = VM2 ■ VMI

[0088] The offset value X determined in this way can be used advantageously. This only requires a design and / or programming of the operator device 20 to determine, in the case of a measurement subsequently carried out after the offset value X has been determined, a measured value V of the magnetic sensor device operating in constant alignment mode, taking into account a difference between a newly measured first differential voltage value VMI minus the determined offset value X according to equation (GL 13) with:

[0089] (GL 13) V = VMI + X

[0090] In this way, measured values ​​V can also be determined in the constant alignment mode of the magnetic sensor device, from which the effects of the thermo-mechanical stress 16 are "corrected out" by using the offset value X. The constant alignment mode, which has a significantly lower energy consumption, can thus be used to determine the measured values ​​V without this being associated with any significant effects of the thermo-mechanical stress 16 present in the magnetic sensor device on the measured values ​​V. In particular, the "switching criterion" explained above can also be combined with the offset value X by choosing the factor n so high that the constant alignment mode is usually used to perform measurements (using the offset value X). The operating strategy of the magnetic sensor device implemented in this way achieves a relatively low energy consumption even with frequent use. R. 414747

[0091] - 17 -

[0092] Preferably, the operator device 20 is designed and / or programmed such that a resetting of the offset value X (only) takes place after a predetermined maximum time has elapsed since the last setting of the offset value X, after a predetermined maximum number of measurements with the previously set offset value, and / or if at least one temperature measured near and / or in the magnetic sensor device exceeds a predetermined temperature threshold, at least one change in the measured temperature over time exceeds a predetermined temperature change threshold, a temperature difference between at least two simultaneously measured temperatures exceeds a predetermined temperature difference threshold, and / or a system interacting with the magnetic sensor device outputs a calibration request signal.This ensures that the offset value X can be redefined as needed, without wasting energy on an unnecessary redefinition of the offset value X.

[0093] Figures 2a to 2c show schematic representations and a coordinate system to explain a second embodiment of the magnetic sensor device.

[0094] The magnetic sensor device schematically depicted in Figures 2a and 2b differs from the previously described embodiment only in the orientation of the polarities 12 of the free positions of some magnetoresistive elements R1 and R2 of its measuring bridge 10. If no magnetic field prevails at the magnetoresistive elements R1 to R4 of the measuring bridge of the magnetic sensor device of Figures 2a to 2c, the polarities 12 of the free positions of the magnetoresistive elements R1 and R2 are oriented opposite to the polarities 12 of the free positions of the magnetoresistive elements R3 and R4, wherein the polarities 14 of the reference positions of all magnetoresistive elements R1 to R4 of the measuring bridge 10 are oriented perpendicular to the polarities 12 of all free positions of the magnetoresistive elements R1 to R4 of the measuring bridge 10, and the polarities 14 of the reference positions of the R. 414747

[0095] - 18 - magnetoresistive elements R1 and R3 are oriented opposite to the polarities 14 of the reference positions of magnetoresistive elements R2 and R4. The operator unit 20 of the magnetic sensor device of Figs. 2a to 2c can thus be designed and / or programmed to control all the functions already explained above.

[0096] Regarding the features and properties of the magnetic sensor device of Figs. 2a to 2c and its advantages, reference is therefore made to the description of the embodiment of Figs. 1a to 1c.

[0097] Fig. 3 shows a flowchart to explain a first embodiment of the method for operating a magnetic sensor device.

[0098] The method described below can, for example, be used to operate one of the magnetic sensor devices shown in Figures 1 and 2. However, it should be noted that the applicability of the method described here is not limited to these magnetic sensor devices. Instead, the method can be carried out with (almost) any magnetic sensor device that has at least one measuring bridge with magnetoresistive elements and at least one conductor component, provided that a magnetic field inducing / varying the orientation of the polarities of the free positions of the magnetoresistive elements is induced by energizing the at least one conductor component.

[0099] The method includes a process step S1 in which a first differential voltage value between two positions of the measuring bridge is determined during operation of the magnetic sensor device in a constant alignment mode, in which the magnetic sensor device is energized and / or held by applying direct current to at least one line component. (See R. 414747)

[0100] - 19 -

[0101] Energizing the at least one line component with direct current can in particular be understood as energizing the at least one line component with only a single current pulse, especially with only one current pulse with a duration of less than or equal to 500 ns (nanoseconds).

[0102] The method also includes a process step S2 in which a second differential voltage value between the two positions of the measuring bridge is determined during operation of the magnetic sensor device in an alternating alignment mode, wherein the magnetic sensor device is brought into and / or maintained in the alternating alignment mode by energizing the at least one conductor component with alternating current. Energizing the at least one conductor component with alternating current can be understood as energizing the at least one conductor component with only two opposing current pulses, in particular with exactly two opposing current pulses, each with a duration of less than or equal to 500 ns (nanoseconds).

[0103] To determine whether, with regard to thermo-mechanical stress occurring in the magnetic sensor device and with regard to a desired low energy consumption of the magnetic sensor device, executing process step S1 instead of process step S2 or executing process step S2 instead of process step S1 is most advantageous, the method also includes a process step S3, which can be repeated, for example, after each execution of process step S1 or process step S2. When process step S3 is executed, at least the magnitude of a difference between the (last determined) first differential voltage value and the (last determined) second differential voltage value is calculated.In process step S3, taking into account at least the determined amount of the difference between the first differential voltage value and the second differential voltage value, a target mode for at least one measurement of the magnetic sensor device is determined by selecting the target mode from an R. 414747.

[0104] - 20 - The set comprising the constant alignment mode realized by process step S1 and the alternating alignment mode effected by process step S2 is selected. In particular, it can be examined whether the relation (R. 1) or the relation (R. 2) specified above exists. If relation (R. 1) exists, process step S2 (instead of process step S1) is executed for the next requested measurement. If, on the other hand, relation (R. 2) exists, the next requested measurement is effected by process step S1 (instead of process step S2). Optionally, after each execution of process step S3, a further process step S4 can wait until a new measurement is requested before the respective requested measurement is executed in the specified target mode.

[0105] The magnetic sensor devices described above can be used, for example, as an angle sensor, especially in a vehicle, or as an e-compass / 3D magnetometer, particularly in consumer electronics, such as a mobile device.

[0106] Fig. 4 shows a flowchart to explain a second embodiment of the method for operating a magnetic sensor device.

[0107] The method of Fig. 4 can also be carried out, for example, using one of the magnetic sensor devices of Figs. 1 and 2. However, it should be noted that the feasibility of the method of Fig. 4 is not limited to these magnetic sensor devices. Instead, the method of Fig. 4 can be carried out with (almost) any magnetic sensor device that has at least one measuring bridge with magnetoresistive elements and at least one conductor component, provided that a magnetic field influencing / varying the orientation of the polarities of the free positions of the magnetoresistive elements is induced by energizing the at least one conductor component. R. 414747

[0108] - 21 -

[0109] The process schematically represented by the flowchart in Fig. 4 also includes the process steps S1 and S2 already explained above, and possibly also the (optional) process step S4. The constant alignment mode described above can be implemented by executing process step S1, while the alternating alignment mode described above is achieved by executing process step S2.

[0110] Instead of process step S3, the method shown in Fig. 4 has a process step S5 in which at least the magnitude of the difference between the (last determined) first differential voltage value and the (last determined) second differential voltage value is determined. In a further process step S6, taking into account the determined magnitude of the difference between the first and second differential voltage values, an offset value X is then set for at least one measurement of the magnetic sensor device operated in constant alignment mode, i.e., by performing process step S1. Optionally, in process step S6, the offset value X can be set equal to the determined magnitude of the difference between the first and second differential voltage values, so that the determined magnitude of the difference can be used immediately for the next measurement carried out by means of process step S1.To avoid sudden jumps in the measured values ​​of the magnetic sensor device, the offset value X can also be gradually adjusted in process step S6 to the determined amount of the difference between the first differential voltage value and the second differential voltage value. For example, the offset value X in process step S6 can be redefined as the average between the previous offset value X and the determined amount of the difference. Alternatively, a low-pass filter could be used. R. 414747.

[0111] - 22 -

[0112] After executing process steps S5 and S6, the process can be continued with process step S1 using the offset value X, or with the (optional) process step S4. In process step S1, executed after process step S6, the respective measured value is then determined taking into account the difference between a newly measured first differential voltage value minus the defined offset value.

[0113] In an (optional) process step S7, it can additionally be determined whether at least one predefined condition exists for resetting the offset value. Process step S7 can be repeated, for example, after each execution of process step S1. The at least one predefined condition could be, for example...The following checks are performed: whether a predetermined maximum time has elapsed since the last setting of the offset value X; whether a predetermined maximum number of measurements have been performed with the previously set offset value; whether at least one temperature measured near and / or in the magnetic sensor device exceeds a predetermined temperature threshold; whether at least one change in the measured temperature over time exceeds a predetermined temperature change threshold; whether a temperature difference between at least two simultaneously measured temperatures exceeds a predetermined temperature difference threshold; and / or whether a system interacting with the magnetic sensor device outputs a calibration request signal. If at least one predetermined condition is met, the procedure of Fig. 4 can be continued with process steps S2, S5, and S6. Otherwise, the procedure of Fig. 4 can be continued with process step S1, or S6 with process step S1.Proceed with process step S4.

[0114] Each of the methods described above can be integrated into software, such as a microcontroller. The methods described above can also be combined with machine learning algorithms. Neural networks and linear regressions can be (co-)used for this purpose. R. 414747

[0115] - 23 - will be. The learning steps can be performed during calibration of the magnetic sensor device, after integration of the magnetic sensor device into an end product, or in a measurement environment of the magnetic sensor device.

[0116] Each of the methods described here can minimize the power consumption of the magnetic sensor device while simultaneously achieving advantageous compensation for the thermo-mechanical stress on the measured values ​​of the magnetic sensor device. Although not shown in Figures 3 and 4, the methods shown in Figures 3 and 4 can also be combined into a single method.

Claims

R. 414747 - 24 - Claims 1. Magnetic sensor device comprising: at least one measuring bridge (10) with magnetoresistive elements (R1 to R4); at least one conductor component (18) by means of which a magnetic field varying a respective orientation of a polarity (12) of the free positions of the magnetoresistive elements (R1 to R4) can be induced;and an operator device (20) which is designed and / or programmed such that, when the magnetic sensor device is in a constant alignment mode in which the magnetic sensor device can be brought into and / or maintained by energizing the at least one line component (18) with direct current, a first differential voltage value between two positions of the measuring bridge (10) can be determined, and, when the magnetic sensor device is in an alternating alignment mode in which the magnetic sensor device can be brought into and / or maintained by energizing the at least one line component (18) with alternating current, a second differential voltage value between the two positions of the measuring bridge (10) can be determined; characterized in that; R. 414747 - 25 - the operator device (20) is additionally designed and / or programmed such that at least an amount of a difference between the second differential voltage value minus the first differential voltage value can be determined by means of the operator device (20), and, taking into account at least the determined amount of the difference between the second differential voltage value minus the first differential voltage value, an offset value for at least one measurement of the magnetic sensor device in the constant alignment mode and / or a target mode of the magnetic sensor device for at least one measurement from a set comprising the constant alignment mode and the alternating alignment mode can be determined by means of the operator device (20).

2. Magnetic sensor device according to claim 1, wherein the operator device (20) is additionally designed and / or programmed such that, by means of the operator device (20), if the determined amount of the difference between the second differential voltage value minus the first differential voltage value is greater than an amount of a product of the second differential voltage value times a predetermined factor, the alternating alignment mode can be set as the target mode.

3. Magnetic sensor device according to claim 2, wherein the operator device (20) is additionally designed and / or programmed such that, by means of the operator device (20), if at least one temperature measured near and / or in the magnetic sensor device is above a predetermined temperature threshold, at least one change in the measured temperature over time is above a predetermined temperature change threshold, a temperature difference between at least two simultaneously measured temperatures is above a predetermined temperature difference threshold, and / or a system interacting with the magnetic sensor device R. 414747 - 26 - The system outputs a change-alignment mode request signal, and the change-alignment mode can be set as the target mode.

4. Magnetic sensor device according to claim 2 or 3, wherein the operator device (20) is additionally designed and / or programmed such that the constant alignment mode can only be set as the target mode by means of the operator device (20) if at least the specified amount of the difference between the second differential voltage value minus the first differential voltage value is less than the amount of the product of the second differential voltage value times the specified factor.

5. Magnetic sensor device according to one of the preceding claims, wherein the operator device (20) is additionally designed and / or programmed such that the offset value can be set by means of the operator device (20) equal to the difference between the second differential voltage value minus the first differential voltage value.

6. Magnetic sensor device according to one of the preceding claims, wherein the operator device (20) is additionally designed and / or programmed such that, after setting the offset value taking into account at least the determined amount of the difference between the second differential voltage value minus the first differential voltage value, a measured value can be determined by means of the operator device (20) taking into account a difference between a newly measured first differential voltage value minus the determined offset value in at least one subsequent measurement of the magnetic sensor device in the constant alignment mode.

7. Magnetic sensor device according to one of the preceding claims, wherein the operator device (20) is additionally designed and / or programmed such that, after the expiry of a predetermined maximum time, R. 414747 - 27 - after the last setting of the offset value, after a predetermined maximum number of measurements with the previously set offset value and / or if at least one temperature measured near and / or in the magnetic sensor device is above a predetermined temperature threshold, at least one time change of the measured temperature is above a predetermined temperature change threshold, a temperature difference between at least two simultaneously measured temperatures is above a predetermined temperature difference threshold and / or a system interacting with the magnetic sensor device outputs a calibration request signal, the offset value can be reset by means of the operator device (20).

8. Magnetic sensor device according to one of the preceding claims, wherein the magnetic sensor device can be transferred and / or maintained in its constant orientation mode by means of only one current pulse (22) with a duration of less than or equal to 500 ns and / or the magnetic sensor device can be transferred and / or maintained in its alternating orientation mode by means of only two opposing current pulses (24a, 24b) each with a duration of less than or equal to 500 ns.

9. Magnetic sensor device according to one of the preceding claims, wherein the magnetoresistive elements (R1 to R4) of the measuring bridge (10) are at least one TMR element, at least one GMR element and / or at least one AMR element.

10. Method for operating a magnetic sensor device with at least one measuring bridge (10) with magnetoresistive elements (R1 to R4) and at least one line component (18), by means of which an energizing current induces a magnetic field varying a respective orientation of a polarity (12) of the free positions of the magnetoresistive elements (R1 to R4), by performing at least one of the following steps: R. 414747 - 28 - Determining a first differential voltage value between two positions of the measuring bridge (10) while the magnetic sensor device is in a constant orientation mode, in which the magnetic sensor device is transferred and / or held by energizing the at least one line component (18) with direct current (S1); and / or Determining a second differential voltage value between the two positions of the measuring bridge (10) while the magnetic sensor device is in an alternating alignment mode in which the magnetic sensor device is transferred and / or held by means of current flowing through at least one line component (18) with alternating current (S2); characterized by the steps: Determine at least the magnitude of a difference between the first differential voltage value and the second differential voltage value (S5); and Determining an offset value for at least one measurement of the magnetic sensor device in constant alignment mode, taking into account at least the determined amount of the difference between the second differential voltage value minus the first differential voltage value (S6) and / or a target mode of the magnetic sensor device for at least one measurement from a set comprising the constant alignment mode and the alternating alignment mode, taking into account at least the determined amount of the difference between the second differential voltage value minus the first differential voltage value (S3).

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