Magnetic angle sensor with symmetrical geometric arrangement

Abstract

Embodiments of the present disclosure relate to a magnetic angle sensor with a symmetric geometric arrangement. The innovative concepts disclosed herein relate to a magnetic angle sensor (100) and a method for operating the same. The sensor (100) comprises a magnetoresistive arrangement (110) and a magnetic source (120) configured to be movable relative to the magnetoresistive arrangement (110). The magnetoresistive arrangement (110) comprises a first magnetoresistive element (111) configured to generate a first output signal (a), a second magnetoresistive element (112) configured to generate a second output signal (b), and a third magnetoresistive element (113) configured to generate a third output signal (c). The first, second, and third magnetoresistive elements (111, 112, 113) are oriented relative to each other such that they form a symmetric geometric arrangement with a relative angular distance between each other.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to a magnetic angle sensor comprising three magnetoresistive elements which are oriented relative to each other such that they form a symmetrical geometric arrangement with equal angular distance between each other. By exploiting the advantages of said symmetrical geometric arrangement, the concept allows the magnetic angle sensor to meet certain safety integrity levels (SIL) at low cost and low complexity. BACKGROUND

[0002] Magnetic angle sensors can be used to determine the angle of rotation of a magnetic source relative to a magnetic sensor. Examples of magnetic angle sensors can include Hall sensors and magnetoresistive sensors, i.e. so-called xMR sensors, which exploit the magnetoresistive effect. The magnetoresistive effect describes the change in resistivity of a (typically ferromagnetic) material in response to an externally applied magnetic field.

[0003] In safety-critical applications, magnetic angle sensors must meet certain minimum safety requirements, which are international standardized by the International Electrotechnical Commission (IEC) in standards IEC 61508 / IEC 61511. These IEC standards define so-called safety integrity levels (SIL) using requirements which are grouped into two categories: hardware safety integrity and system safety integrity. A device or system must meet the requirements for both categories to achieve a given SIL. SIL is defined as the relative level of risk reduction provided by a safety function, or is defined to specify a target level of risk reduction. In simple terms, SIL is a measure of the performance required of a safety instrumented function.

[0004] In some technical fields, specialized safety integrity levels are conceptualized. For example, in the automotive industry, so-called ASILs (Automotive Safety Integrity Levels) are application risk classification standards defined by ISO 22262, which is a functional safety standard for road vehicles. This is an adaptation of the safety integrity levels (SIL) in IEC 61508 for the automotive industry. ASILs are built by performing a risk analysis of potential hazards by considering the severity, exposure, and controllability of the vehicle operating scenario. The safety goal against this hazard in turn carries the ASIL requirements.

[0005] In the field of magnetic angle sensors, it is required that they meet certain fail-safe operation requirements, e.g. provided by a redundancy concept or similar. For example, it is desirable to provide redundant signals and angle measurements with the same sensor. Furthermore, it is desirable to precisely measure magnetic field components, even if the magnetic field strength can be small. Magnetoresistive angle sensors can be preferred, as they deliver precise measurements even in harsh environments. However, existing magnetoresistive sensors that meet certain safety standards, such as one or more levels in SIL or ASIL, can use rather complex circuit layouts, which have an impact on their form factor (size) and production costs.

[0006] Therefore, it is desirable to provide a magnetoresistive sensor with a simple and thus cost-efficient layout, while including a small form factor and meeting the requirements of certain safety standards. SUMMARY

[0007] This object is achieved according to the independent claims by the magnetoresistive sensor and the corresponding method of operating the magnetoresistive sensor as disclosed herein. Further embodiments and advantageous aspects are suggested in the dependent claims.

[0008] According to the innovative concept described herein, a magnetic angle sensor is provided, which comprises a magnetoresistive arrangement and a magnetic source configured to be movable relative to the magnetoresistive arrangement. The magnetoresistive arrangement comprises a first magnetoresistive element configured to generate a first output signal depending on a positional relationship between the magnetic source and the first magnetoresistive element, a second magnetoresistive element configured to generate a second output signal depending on a positional relationship between the magnetic source and the second magnetoresistive element, and a third magnetoresistive element configured to generate a third output signal depending on a positional relationship between the magnetic source and the third magnetoresistive element. According to the innovative principle, the first, second and third magnetoresistive elements are oriented relative to each other such that they form a symmetrical geometric arrangement with equal angular distances between them.

[0009] Furthermore, a method for operating such a magnetic angle sensor is provided, wherein the method comprises the steps of providing a magnetoresistive arrangement with a first, a second and a third magnetoresistive element, which are oriented relative to each other such that they form a symmetrical geometric arrangement with equal angular distances between each other. The method further comprises the steps of deriving a first output signal (a) from the first magnetoresistive element depending on the positional relationship between a magnetic source and the first magnetoresistive element, and deriving a second output signal (b) from the second magnetoresistive element depending on the positional relationship between the magnetic source and the second magnetoresistive element, and deriving a third output signal (c) from the third magnetoresistive element depending on the positional relationship between the magnetic source and the third magnetoresistive element. The method further comprises the steps of determining three differential signals (dl, d2, d3) depending on the output signals (a, b, c), wherein a first differential signal (dl = b - a) is based on the difference between the first output signal (a) and the second output signal (b), a second differential signal (d2 = c - b) is based on the difference between the second output signal (b) and the third output signal (c), and a third differential signal (d3 = a - c) is based on the difference between the first output signal (a) and the third output signal (c). Furthermore, the method comprises calculating at least three angle signals (al, a2, a3) depending on the three differential signals (dl, d2, d3), wherein each of the three angle signals (al, a2, a3) represents a rotational angle of the magnetic source (120) relative to the magnetoresistive arrangement (110), wherein a first angle signal (al) is calculated depending on the first differential signal (dl) and the second differential signal (d2), a second angle signal (a2) is calculated depending on the second differential signal (d2) and the third differential signal (d3), and a third angle signal (a3) is calculated depending on the first differential signal (dl) and the third differential signal (d3).

[0010] Furthermore, a computer program is provided, wherein each computer program is configured to implement the above-mentioned method when executed on a computer or signal processor, such that the above-mentioned method is implemented by one of the computer programs. BRIEF DESCRIPTION OF DRAWINGS

[0011] In the following, embodiments of the present disclosure are described in more detail with reference to the accompanying drawings, in which

[0012] Figure 1 A schematic diagram of a magnetic angle sensor according to one embodiment is shown,

[0013] Figure 2 A schematic diagram of a magnetic angle sensor according to another embodiment is shown,

[0014] Figure 3 A magnetic angle sensor in Figure 1 is shown in combination with a family of curves illustrating generated single-ended signals,

[0015] Figure 4 It shows Figure 1 The magnetic angle sensor in the diagram is combined with the family of curves representing the generated differential signal.

[0016] Figure 5 shows a family of curves used to illustrate how to calculate the applied angle based on the differential signal.

[0017] Figure 6 A vector diagram illustrating how to calculate a fourth angle signal from three differential signals and how to calculate the fourth applied angle is shown.

[0018] Figure 7 A schematic diagram of a possible hardware implementation of a magnetic angle sensor according to one embodiment is shown.

[0019] Figure 8 A schematic flowchart illustrating the innovative principles described in this article is shown.

[0020] Figure 9A , Figure 9B A magnetic angle sensor according to one embodiment is shown. Figure 9B ) and existing TMR-based angle sensors ( Figure 9A An illustrative comparison between ) and , and

[0021] Figure 10 A schematic block diagram of a method for operating a magnetic angle sensor according to one embodiment is shown. Detailed Implementation

[0022] In the following description, equivalent or related elements, or elements having equivalent or related functions, are indicated by equivalent or related reference numerals.

[0023] The method steps described in block diagram form and referenced to the block diagram may also be performed in a different order than those described and / or illustrated. Furthermore, method steps relating to specific features of the device may be replaced with those features of the device, and vice versa.

[0024] Figure 1 A schematic diagram of a magnetic angle sensor 100 according to an embodiment of the innovative concept described herein is shown. The angle sensor 100 includes a magnetoresistive arrangement 110 and a magnetic source 120 configured to be movable relative to the magnetoresistive arrangement 110.

[0025] Magnetic source 120 may include a magnetic north pole 121 and a magnetic south pole 122. Magnetic source 120 can generate a magnetic field, such as an in-plane magnetic field (i.e., within the chip plane) exemplarily depicted as arrow 130. Magnetic source 120 can be moved relative to magnetoresistive arrangement 110. For example, magnetic source 120 can be rotated relative to magnetoresistive arrangement 110, such as... Figure 1 The figure depicted in the lower left corner rotates around the central axis 140 degrees.

[0026] The magnetoresistive arrangement 110 includes a first magnetoresistive element 111, which is configured to generate a first output signal (a) based on the positional relationship between the magnetic source 120 and the first magnetoresistive element 111.

[0027] The magnetoresistive arrangement 110 includes a second magnetoresistive element 112, which is configured to generate a second output signal (b) based on the positional relationship between the magnetic source 120 and the second magnetoresistive element 112.

[0028] The magnetoresistive arrangement 110 includes a third magnetoresistive element 113, which is configured to generate a third output signal (c) based on the positional relationship between the magnetic source 120 and the third magnetoresistive element 113.

[0029] Based on the innovative principle described herein, the first, second, and third magnetoresistive elements 111, 112, and 113 are oriented relative to each other in a symmetrical geometric arrangement such that they form an equidistant (i.e., equidistant) angular distance β between each other. The angular distance β may correspond to the angle β between one of the magnetoresistive elements 111, 112, and 113 and an adjacent one of the magnetoresistive elements 111, 112, and 1143.

[0030] As mentioned above, the geometric arrangement of the magnetoresistive elements 111, 112, and 113 is a symmetrical geometric arrangement, that is, each magnetoresistive element 111, 112, and 113 includes the same angular distance β between each other.

[0031] exist Figure 1 In the embodiment shown, the first, second, and third magnetoresistive elements 111, 112, and 113 are arranged in a symmetrical star topology with an equidistant angular distance β = 120° between them.

[0032] Figure 2 Another embodiment is shown, wherein the first, second, and third magnetoresistive elements 111, 112, and 113 are arranged in a symmetrical equiangular triangle with an equidistant angular distance β = 60° between them.

[0033] Each of magnetoresistive elements 111, 112, and 113 may include at least one of the following:

[0034] TMR devices (TMR: Tunneling Magnetoresistance),

[0035] GMR devices (GMR: Giant Magnetoresistance),

[0036] CMR equipment (CMR: giant magnetoresistance),

[0037] EMR equipment (EMR: Extremely High Magnetoresistive), and

[0038] AMR devices (AMR: Anisotropic Magnetoresistance)

[0039] These magnetoresistive devices can be classified as so-called xMR devices. Therefore, each of the first, second, and third magnetoresistive elements 111, 112, and 113 may include at least one xMR device.

[0040] like Figure 1 and Figure 2 As exemplarily depicted, each of the magnetoresistive elements 111, 112, and 113 may include or be configured as an xMR device having at least two xMR elements 111A and 111B connected in a bridging circuit. Therefore, the xMR device may also be referred to as an xMR stack. For example, if the xMR device is a TMR device, the first TMR element 111A may be a first magnetic tunnel junction (MTJ), and the second TMR element 112B may be a second magnetic tunnel junction. The two xMR elements 111A and 111B may include antiparallel magnetization, as exemplarily depicted by arrows within the respective xMR elements 111A and 111B.

[0041] When an xMR device is configured as an AMR device, it will exhibit a half-turn signal (180 degrees) compared to GMR and TMR devices (360 degrees). Therefore, AMR devices are also suitable for the innovative concept described herein with a splitting factor of 2.

[0042] The following embodiments will be described with reference to the star topology described above, wherein the equidistant angular distance β between magnetoresistive elements 111, 112, and 113 is 120°. Figure 1 However, this innovative concept also applies to the equiangular triangular topology with an equidistant angular distance β = 60° between the magnetoresistive elements 111, 112, and 113 mentioned above.

[0043] Figure 3 A magnetoresistive arrangement 110 in a star topology is shown, comprising first, second, and third magnetoresistive elements 111, 112, and 113. The magnetoresistive arrangement 110 generates three sinusoidal signals (a), (b), and (c), which are phase-shifted by an amount corresponding to the angular distance β. According to the star topology, the equidistant angular distance is β = 120°, and therefore, the phase difference between each of the three sinusoidal signals (a), (b), and (c) is Δθ = 120°. For an equiangular triangular topology (…),… Figure 2The equidistant angular distance is β = 60°, and therefore, the phase difference between each of the three sinusoidal signals (a), (b), and (c) is Δθ = 60°.

[0044] Each of the three sinusoidal signals (a), (b), and (c) may include an offset "O" that can be derived from the homogeneous magnetic interference field. Therefore, each of the three sinusoidal signals (a), (b), and (c) may include an amplitude "A", a phase angle θ having the aforementioned phase difference Δθ, and an offset value "O". Thus, the first magnetoresistive element 111 can generate the first signal a = A·cos(θ) + O, and the second magnetoresistive element 112 can generate the second signal. Furthermore, the third magnetoresistive element 113 can generate a third signal. Since these signals (a), (b), and (c) are derived from a single magnetoresistive element 111, 112, and 113, they are also referred to as single-ended signals in this paper.

[0045] Figure 4 Another embodiment is shown. A controller (not shown) connected to the magnetoresistive arrangement 110 can be configured to determine three differential signals from the single-ended output signals (a), (b), and (c) mentioned above, wherein

[0046] The first differential signal d1 is based on a combination of the first output signal (a) and the second output signal (b), for example, according to: d1 = b – a (this is equivalent to: d1 = a – b, but with different signs).

[0047] The second differential signal d2 is based on a combination of the second output signal (b) and the third output signal (c), for example, according to: d2 = c – b (this is equivalent to: d2 = b – c, but with different signs).

[0048] The third differential signal d3 is based on the combination of the first output signal (a) and the third output signal (c), for example, according to: d3 = a – c (which is equivalent to: d3 = c – a, but with different signs).

[0049] In the case that the items mentioned above are single-ended signals (a), (b), and (c), the differential signals d1, d2, and d3 will be:

[0050]

[0051]

[0052]

[0053] As in Figure 4 As can be seen in the right part, the offset "O" is canceled out, the phase difference Δθ remains unchanged, and the amplitude "A" is factored. Increase.

[0054] The differential signals d1, d2, and d3 can be used to calculate the rotation angle between the magnetic source 120 and the reluctance arrangement 110. As can be seen in Figure 5, by applying the tangent (tan) function, three different rotation angles α1, α2, and α3 can be calculated based on the three differential signals d1, d2, and d3.

[0055] Therefore, according to some embodiments, the controller can be configured to calculate three angle signals α1, α2, α3 based on three differential signals d1, d2, d3, wherein each of the angle signals α1, α2, α3 represents a rotation angle of the magnetic source 120 relative to the magnetoresistive arrangement 110, and wherein the controller is configured to:

[0056] The first angle signal α1 is calculated based on the combination of the first differential signal d1 and the second differential signal d2.

[0057] The second angle signal α2 is calculated based on the combination of the second differential signal d2 and the third differential signal d3.

[0058] The third angle signal α3 is calculated based on the combination of the first differential signal d1 and the third differential signal d3.

[0059] Specifically, the first angle signal α1 can be calculated according to the following equation:

[0060]

[0061] The second angle signal α2 can be calculated according to the following equation:

[0062]

[0063] The third angle signal α3 can be calculated using the following equation:

[0064]

[0065] These angle signals α1, α2, and α3 represent the angle information that the magnetic angle sensor 100 may output in its respective application. Therefore, these angle signals α1, α2, and α3 can also be referred to as the application angle.

[0066] However, in addition to calculating the applied angle, the magnetic angle sensor 100 according to the innovative concept described herein can also be configured to apply safety mechanisms or safety measurements using one or more of these applied angles α1, α2, α3 respectively. This can be performed to check whether the magnetic angle sensor 100 complies with certain safety regulations, such as SIL or ASIL.

[0067] For example, the controller can be configured to perform a safety measurement based on the first, second, and third angle signals α1, α2, α3 by comparing them with each other, and to determine whether they are equal or deviate from each other. Therefore, the controller can be configured to check whether:

[0068] α1≈α2≈α3 (Equation 7)

[0069] If the controller can determine that the angle signals α1, α2, and α3 are equal, then the controller can be configured to derive that the angle calculation based on all differential signals d1, d2, and d3 is correctly performed. Additionally or alternatively, the controller can be configured to derive that the calculation of the differential signals d1, d2, and d3 using single-ended signals (a), (b), and (c) is correct. However, further additionally or alternatively, the controller can be configured to derive that each of the magnetoresistive elements 111, 112, and 113 functions normally, and each of the magnetoresistive elements 111, 112, and 113 generates a valid signal.

[0070] It is important to note that, depending on the current rotational position of the magnetic source 120 relative to the magnetoresistive arrangement 110, each of the magnetoresistive elements 111, 112, and 113 generates single-ended signals (a), (b), and (c), but with different phase angles. This means that at any given time, each of the magnetoresistive elements 111, 112, and 113 should provide the same signal (at least in terms of its amplitude and signal shape), but with different phase angles, such as θ. and

[0071] Therefore, if the controller can determine that the angle signals α1, α2, α3 are not equal, i.e., if they may deviate from each other by a certain amount, then the controller can be configured to derive: the angle calculation based on all differential signals d1, d2, d3 was not performed correctly. The controller can be configured to derive: the calculation of differential signals d1, d2, d3 using single-ended signals (a), (b), (c) is incorrect. Furthermore, the controller can be configured to derive: at least one of the magnetoresistive elements 111, 112, 113 is not functioning properly, and at least one of the magnetoresistive elements 111, 112, 113 generates an invalid signal. Therefore, the controller can be configured to derive: at least one of the magnetoresistive elements 111, 112, 113 may be faulty.

[0072] By comparing at least one of the angle signals α1, α2, α3, differential signals d1, d2, d3, and single-ended signals (a), (b), (c) with each other, the controller can be configured to determine which of the magnetoresistive elements 111, 112, 113 may be malfunctioning or faulty. In some embodiments, the controller can be configured to generate indications, such as acoustic and / or optical alarms, for notifying the user that the magnetic angle sensor 100 may be faulty and / or for notifying the user which of the magnetoresistive elements 111, 112, 113 may be faulty.

[0073] Therefore, if the controller can determine that one of the first, second, and third angle signals α1, α2, and α3 deviates from the other angle signals by a certain amount, that is, if the controller can determine that at least one of the following conditions is met:

[0074]

[0075]

[0076]

[0077]

[0078]

[0079] Therefore, the controller can be configured to detect based on the determined deviation angle signal:

[0080] One of the first, second, and third magnetoresistive elements 111, 112, and 113 generates a faulty output signal, and / or

[0081] Which of the first, second, and third magnetoresistive elements 111, 112, and 113 generates the faulty output signal?

[0082] Based on the innovative principles described in this paper, in addition to the three application angles α1, α2, and α3 discussed above, a fourth application angle α4 can also be calculated. This additional fourth application angle α4 can also be used as a security measure to apply a higher level of security, such as in terms of SIL or ASIL.

[0083] like Figure 6As can be seen, the controller can be configured to calculate the fourth angle signal α4 based on a combination of the first differential signal d1, the second differential signal d2, and the third differential signal d3. This means that the controller can be configured to calculate the fourth angle signal α4 without providing a fourth magnetoresistive element. Therefore, according to the innovative concept described herein, exactly three magnetoresistive elements 111, 112, and 113 are sufficient to calculate the four different angle signals α1, α2, α3, and α4 that can be used to calculate the applied angle and to perform safety measurements.

[0084] The controller can be configured to calculate the fourth angle signal α4 based on the first, second, and third differential signals d1, d2, and d3 according to the following equation:

[0085]

[0086] exist Figure 6 The left portion of the diagram illustrates a vector diagram used to illustrate the calculation of the fourth angle signal α4 based on three differential signals d1, d2, and d3. According to the vector diagram, the rotation vector of the differential signal d4 is the sum of the rotation vectors of the differential signals d1, d2, and d3. The corresponding phase angle α4 can be calculated according to Equation 12.

[0087] In some embodiments, the controller can be configured to apply safety mechanisms or safety measurements using one or more of the four application angles α1, α2, α3, α4, respectively. This can be performed to check whether the magnetic angle sensor 100 complies with certain safety regulations, such as SIL or ASIL.

[0088] For example, the controller can be configured to perform safety measurements based on the first, third, and fourth angle signals α1, α2, α3, α4 by comparing them with each other, and to determine whether they are equal or deviate from each other. Therefore, the controller can be configured to check whether:

[0089] α1≈α2≈α3≈α4 (Equation 13)

[0090] If the controller can determine that the angle signals α1, α2, α3, and α4 are equal, then the controller can be configured to derive that the angle calculations for the four angle signals α1, α2, α3, and α4 based on the three differential signals d1, d2, and d3 are correctly performed. Additionally or alternatively, the controller can be configured to derive that the calculations for the differential signals d1, d2, and d3 using single-ended signals (a), (b), and (c) are correct. However, further additionally or alternatively, the controller can be configured to derive that each of the magnetoresistive elements 111, 112, and 113 functions normally, and each of the magnetoresistive elements 111, 112, and 113 generates a valid signal.

[0091] Conversely, if the controller can determine that the angle signals α1, α2, and α3 are not equal, i.e., if they may deviate from each other by a certain amount, then the controller can be configured to derive: the angle calculation of the four angle signals α1, α2, α3, and α4 based on the three differential signals d1, d2, and d3 was not performed correctly. The controller can be configured to derive: the calculation of the differential signals d1, d2, and d3 using single-ended signals (a), (b), and (c) is incorrect. Furthermore, the controller can be configured to derive: at least one of the magnetoresistive elements 111, 112, and 113 is not functioning properly, and at least one of the magnetoresistive elements 111, 112, and 113 generates an invalid signal. Therefore, the controller can be configured to derive: at least one of the magnetoresistive elements 111, 112, and 113 may be faulty.

[0092] By comparing at least one of the angle signals α1, α2, α3, α4, the differential signals d1, d2, d3, and the single-ended signals (a), (b), (c) with each other, the controller can be configured to determine which of the magnetoresistive elements 111, 112, 113 may be malfunctioning or potentially faulty. In some embodiments, the controller can be configured to generate indications, such as acoustic and / or optical alarms, for notifying the user that the magnetic angle sensor 100 may be faulty and / or for notifying the user which of the magnetoresistive elements 111, 112, 113 may be faulty.

[0093] Therefore, if the controller can determine that one of the first, second, third, and fourth angle signals α1, α2, α3, and α4 deviates by a certain amount from the other angle signals, then the controller can be configured to detect based on the determined deviation angle signal:

[0094] One of the first, second, and third magnetoresistive elements 111, 112, and 113 generates a faulty output signal, and / or

[0095] Which of the first, second, and third magnetoresistive elements 111, 112, and 113 generates the faulty output signal?

[0096] For safety reasons, the four angle signals α1, α2, α3, and α4 are calculated based on the three differential signals d1, d2, and d3 as mentioned above. Additionally or alternatively, the controller can be configured to increase / enhance the safety level by performing further safety integrity double-check verification according to the following equation:

[0097]

[0098] According to Equation 14 above, the controller can be configured to perform security measurements based on the first, second, and third differential signals d1, d2, d3 by checking whether the sum of the first quadratic term containing the first and third differential signals d1 and d3 and the second quadratic term containing the first, second, and third differential signals d1, d2, d3 is a constant.

[0099] First and second terms This can correspond to the cosine of the fourth angle signal α4. 2 And the second quadratic term This can correspond to the sin of the fourth angle signal α4. 2 Therefore, based on the fourth angle signal α4, it is possible to check whether the criterion cos 2 α4+sin 2 α4 = 1.

[0100] If the controller can determine that the criteria in Equation 14 are met, then the controller can be configured to derive that the angle calculations for the four angle signals α1, α2, α3, and α4 based on the three differential signals d1, d2, and d3 are correctly performed. Additionally or alternatively, the controller can be configured to derive that the calculations for the differential signals d1, d2, and d3 using the single-ended signals (a), (b), and (c) are correct. However, further additionally or alternatively, the controller can be configured to derive that each of the magnetoresistive elements 111, 112, and 113 functions normally, and each of the magnetoresistive elements 111, 112, and 113 generates a valid signal.

[0101] Conversely, if the controller can determine that the criteria in Equation 14 are not met, then the controller can be configured to derive that the angle calculations for the four angle signals α1, α2, α3, and α4 based on the three differential signals d1, d2, and d3 were not performed correctly. The controller can be configured to derive that the calculations for the differential signals d1, d2, and d3 using single-ended signals (a), (b), and (c) are incorrect. Furthermore, the controller can be configured to derive that at least one of the magnetoresistive elements 111, 112, and 113 is not functioning properly, and at least one of the magnetoresistive elements 111, 112, and 113 generates an invalid signal. Therefore, the controller can be configured to derive that at least one of the magnetoresistive elements 111, 112, and 113 may be faulty. In some embodiments, the controller can be configured to determine which of the magnetoresistive elements 111, 112, and 113 may be malfunctioning or faulty.

[0102] Figure 7 Possible hardware configurations of the magnetic angle sensor 100 described herein are illustrated. The magnetoresistive arrangement 110 may include the three magnetoresistive elements 111, 112, and 113 mentioned above, which are oriented relative to each other such that they form a symmetrical geometric arrangement with equal angular distances between them, for example, a star topology with 120° equidistant angular distances or an equiangular triangle configuration with 60° equidistant angular distances.

[0103] The first magnetoresistive element 111 can generate a first analog output signal (a). The second magnetoresistive element 112 can generate a second analog output signal (b). The third magnetoresistive element 113 can generate a third analog output signal (c). The first, second, and third analog output signals (a), (b), and (c) can be fed into the controller 150.

[0104] The controller 150 may include an ADC (analog-to-digital converter) for discretizing the analog output signals (a), (b), and (c). For example, a first ADC "ADC1" may be configured to convert the first analog output signal (a) into a first digital output signal, a second ADC "ADC2" may be configured to convert the second analog output signal (b) into a second digital output signal, and a third ADC "ADC3" may be configured to convert the third analog output signal (c) into a third digital output signal.

[0105] like Figure 7As shown, the magnetic angle sensor 100 can be implemented using a magnetoresistive arrangement 110, which is configured as an analog sensor with an external processor (controller) 150. Alternatively, the magnetic angle sensor 100 can be implemented using a magnetoresistive arrangement 110 and a controller 150 integrated on a single chip, wherein the controller 150 is configured as an integrated DSP (digital signal processor).

[0106] Figure 8 This provides a schematic overview of the innovative principles described in this article. For example... Figure 7 As shown in the diagram, this schematic assumes that the magnetic angle sensor 100 is implemented using the analog-to-digital converter described above. However, it is also applicable to a single chip with a DSP.

[0107] In box 181, differential measurements are performed, and based on these measurements, referring to equations 1, 2, and 3 as described above, three differential signals d1, d2, and d3 are calculated from the three single-ended signals (a), (b), and (c). As can be seen in box 181, this can be achieved by using the outputs of analog-to-digital converters “ADC1,” “ADC2,” and “ADC3,” respectively. To emphasize that the three differential signals are not yet normalized, they are referred to in box 181 using the uppercase letters D1, D2, and D3.

[0108] Box 181 illustrates an optional step in which the differential signals D1, D2, and D3 can be normalized, for example, by performing AOP (amplitude-phase shift) calibration.

[0109] In box 183, at least three, and preferably four, angle signals α1, α2, α3, and α4 can be calculated from the three differential signals d1, d2, and d3, as described above with reference to equations 4, 5, 6, and 12. These four angle signals α1, α2, α3, and α4 can be used as so-called applied angles. That is, these four angle signals α1, α2, α3, and α4 can represent and indicate the angular position of the magnetic source 120 relative to the magnetoresistive arrangement 110.

[0110] The magnetic angle sensor 100 of the innovative concept described herein can be configured to provide a safety integrity check mechanism to improve its safety integrity level. Therefore, in block 184, two different safety measurements can be performed, wherein in the first safety measurement, the calculated angle signals α1, α2, α3, α4 can be compared with each other to determine a deviation of at least one of the four angle signals α1, α2, α3, α4; that is, the controller 150 can be configured to check whether α1≈α2≈α3≈α4.

[0111] Alternatively or additionally, in the second security measurement, differential signals d1, d2, and d3 can be used for additional security integrity checks, wherein the controller 150 can be configured to verify whether the standard is met.

[0112] Figure 9A and Figure 9B The innovative magnetic angle sensor 100 described herein is shown. Figure 9B ) and the existing TMR-based sensor 900 ( Figure 9A An overview of the advantages compared to [other components].

[0113] Existing sensor concepts use four TMR elements 911, 912, 913, 914, where each TMR element includes a pair of two TMR stacks 901, ..., 908. In total, the existing sensor 900 uses eight TMR stacks 901, ..., 908, and because four TMR elements 911, 911, 913, and 914 are required, a four-channel ADC is correspondingly needed.

[0114] Two TMR elements 911 and 912 are connected by a positive bridge, while two other TMR elements 913 and 914 are connected by a negative bridge. Each pair, that is, each TMR element 911, 912, 913, and 914, generates one cosine signal and one sinine signal. Therefore, the negative bridge generates a negative cosine signal 921 and a negative sinine signal 922, while the positive bridge generates a positive cosine signal 923 and a positive sinine signal 924.

[0115] Using this existing sensor concept, two differential signals can be generated: (SIN-P – COS_P) and (SIN_N – COS_N). Therefore, only one application angle can be calculated from these two differential signals. Furthermore, the two application angles derived from the four single-ended signals can be used for safety measurements.

[0116] The innovative concept described herein uses only three magnetoresistive elements 111, 112, and 113. Each magnetoresistive element 111, 112, and 113 may include two magnetoresistive stacks. Therefore, this magnetic angle sensor 100 uses only six magnetoresistive stacks instead of the eight TMR stacks in the existing sensor concept 900.

[0117] Since only three magnetoresistive elements 111, 112, and 113 are used, a three-channel ADC is sufficient, instead of the four-channel ADC used in the existing sensor concept 900. Using the three magnetoresistive elements 111, 112, and 113 arranged in a symmetrical magnetoresistive arrangement 110 as described herein, three differential signals d1, d2, and d3 can be generated instead of the two differential signals in the existing sensor concept 900.

[0118] Using this innovative magnetic angle sensor 100, four application angles α1, α2, α3, and α4 can be calculated, instead of just one application angle as in the existing sensor concept 900. Furthermore, according to the innovative magnetic angle sensor 100, these four angle signals α1, α2, α3, and α4 can also be used for safety measurements, instead of just two angles as in the existing sensor concept 900.

[0119] Figure 10 A schematic block diagram of a method for operating a magnetic angle sensor 100 according to the innovative principles described herein is shown.

[0120] In block 201, the magnetoresistive arrangement 110 is provided with first, second, and third magnetoresistive elements 111, 112, and 113, which are oriented relative to each other in a symmetrical geometric (e.g., star-shaped or isogonal triangular) arrangement with equal angular distances between them.

[0121] In block 202, a first single-ended output signal (a) is derived from the first magnetoresistive element 111, and a first output signal (b) is derived based on the positional relationship between the magnetic source 120 and the first magnetoresistive element 111. Furthermore, a second single-ended input signal (b) is derived from the second magnetoresistive element 112, and a second output signal (b) is derived based on the positional relationship between the magnetic source 120 and the second magnetoresistive element 112. Additionally, a third single-ended output signal (c) is derived from the third magnetoresistive element 113, and a third output signal (c) is derived based on the positional relationship between the magnetic source 120 and the third magnetoresistive element 113.

[0122] In box 203, three differential signals d1, d2, and d3 are determined based on the single-ended output signals (a), (b), and (c), where...

[0123] The first differential signal d1 = b – a is based on the combination of the first output signal (a) and the second output signal (b).

[0124] The second differential signal d2 = c – b is based on the combination of the second output signal (b) and the third output signal (c).

[0125] The third differential signal d3 = a – c is based on the combination of the first output signal (a) and the third output signal (c).

[0126] In box 204, at least three angle signals α1, α2, and α3 are calculated based on three differential signals d1, d2, and d3, where each of the three angle signals α1, α2, and α3 represents a rotation angle of the magnetic source 120 relative to the magnetoresistive arrangement 110.

[0127] The first angle signal α1 is calculated based on the first differential signal d1 and the second differential signal d2.

[0128] The second angle signal α2 is calculated based on the second differential signal d2 and the third differential signal d3.

[0129] The third angle signal α3 is calculated based on the first differential signal d1 and the third differential signal d3.

[0130] As mentioned above, three angle signals α1, α2, and α3, or even four angle signals α1, α2, α3, and α4, can be calculated from three differential signals d1, d2, and d3. Furthermore, two different safety measurements can be performed using the following method:

[0131] Check if α1≈α2≈α3≈α4

[0132] And / or by checking whether

[0133]

[0134] Although some aspects have already been described in the context of the apparatus, it is clear that these aspects also represent descriptions of the corresponding methods, where a box or device corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method step also represent descriptions of corresponding boxes, items, or features of the corresponding apparatus.

[0135] Some or all of the method steps may be performed by (or by using) hardware devices, such as microprocessors, programmable computers, or electronic circuits. In some embodiments, such devices may perform one or more of the most important method steps.

[0136] Depending on certain implementation requirements, the embodiments may be implemented in hardware or software, or at least partially in hardware, or at least partially in software. The implementation can be performed using digital storage media such as floppy disks, DVDs, Blu-ray discs, CDs, ROMs, PROMs, EPROMs, EEPROMs, or flash memory, which stores electronically readable control signals that cooperate (or are capable of cooperating with) a programmable computer system to cause the corresponding method to be executed. Therefore, the digital storage medium can be computer-readable.

[0137] Some embodiments include a data carrier having electronically readable control signals that can cooperate with a programmable computer system to enable one of the methods described herein to be performed.

[0138] Typically, an embodiment can be implemented as a computer program product having program code that, when run on a computer, is operable to perform one of the methods. For example, the program code can be stored on a machine-readable medium.

[0139] Other embodiments include a computer program for performing one of the methods described herein, the program being stored on a machine-readable medium.

[0140] In other words, one embodiment of the method disclosed herein is therefore a computer program having program code for performing one of the methods described herein when the computer program is run on a computer.

[0141] Therefore, another embodiment of the method disclosed herein is a data carrier (or digital storage medium or computer-readable medium) including a computer program recorded thereon for performing one of the methods described herein. Data carriers, digital storage media, or recording media are generally tangible and / or non-transitory.

[0142] Therefore, another embodiment of the method disclosed herein represents a data stream or signal sequence for performing one of the methods described herein. The data stream or signal sequence may, for example, be configured to be transmitted via a data communication connection (e.g., via the Internet).

[0143] Another embodiment includes a processing component, such as a computer or programmable logic device, configured or adapted to perform one of the methods described herein.

[0144] Another embodiment includes a computer on which a computer program for performing one of the methods described herein is installed.

[0145] Another embodiment includes an apparatus or system configured to transmit (e.g., electronically or optically) a computer program for performing one of the methods described herein to a receiver. For example, the receiver may be a computer, a mobile device, a memory device, etc. For example, the apparatus or system may include a file server for transmitting the computer program to the receiver.

[0146] In some embodiments, a programmable logic device (e.g., a field-programmable gate array) may be used to perform some or all of the functionality of the methods described herein. In some embodiments, the field-programmable gate array may cooperate with a microprocessor to perform one of the methods described herein. Generally, the methods are preferably performed by any hardware device.

[0147] The apparatus described herein can be implemented using hardware devices, or using a computer, or a combination of hardware devices and a computer.

[0148] The methods described herein can be performed using hardware devices, computers, or a combination of hardware devices and computers.

[0149] While this disclosure has been described with reference to illustrative embodiments, it is not intended to be interpreted in a limiting sense. Various modifications and combinations of exemplary embodiments and other embodiments of this disclosure will be apparent to those skilled in the art upon reference to this specification. Therefore, the appended claims are intended to cover any such modifications or embodiments.

Claims

1. A magnetic angle sensor (100), comprising: A magnetoresistive arrangement (110) and a magnetic source (120), the magnetic source (120) being configured to be movable relative to the magnetoresistive arrangement (110). The magnetoresistive arrangement (110) includes: The first magnetoresistive element (111) is configured to generate a first output signal (a) based on the positional relationship between the magnetic source (120) and the first magnetoresistive element (111). The second magnetoresistive element (112) is configured to generate a second output signal (b) based on the positional relationship between the magnetic source (120) and the second magnetoresistive element (112). The third magnetoresistive element (113) is configured to generate a third output signal (c) based on the positional relationship between the magnetic source (120) and the third magnetoresistive element (113). The first magnetoresistive element (111), the second magnetoresistive element (112), and the third magnetoresistive element (113) are oriented relative to each other in a symmetrical geometric arrangement such that they form a symmetrical arrangement with equal angular distances between them. The magnetic angle sensor also includes a controller configured to determine three differential signals ( d 1 、d 2 、 d 3 ),in First differential signal ( d 1 =b–a Based on the combination of the first output signal (a) and the second output signal (b), The second differential signal ( d 2 =c–b Based on the combination of the second output signal (b) and the third output signal (c), and The third differential signal ( d 3 =a–c Based on the combination of the first output signal (a) and the third output signal (c), The controller is configured to operate based on the three differential signals ( d 1 、d 2 、d 3 To calculate three angle signals ( α 1 、 α 2 、α 3 ), wherein the angle signal ( α 1 、α 2 、α 3 Each angle signal in the diagram represents a rotation angle of the magnetic source (120) relative to the magnetoresistive arrangement (110), and the controller is configured to: According to the first differential signal ( d 1 ) and the second differential signal ( d 2 The combination of these signals is used to calculate the first angle signal. α 1 ), According to the second differential signal ( d 2 ) and the third differential signal ( d 3 The combination of these signals is used to calculate the second angle signal. α 2 ),as well as According to the first differential signal ( d 1 ) and the third differential signal ( d 3 The combination of these signals is used to calculate the third angle signal. α 3 ).

2. The magnetic angle sensor (100) according to claim 1. The first magnetoresistive element (111), the second magnetoresistive element (112), and the third magnetoresistive element (113) are arranged in a symmetrical star shape with an angular distance of 120° between them.

3. The magnetic angle sensor (100) according to claim 1. in, The first magnetoresistive element (111), the second magnetoresistive element (112) and the third magnetoresistive element (113) are arranged in a symmetrical equiangular triangle with an angular distance of 60° between them.

4. The magnetic angle sensor (100) according to claim 1. The controller is configured to: pass the first angle signal ( α 1 ), the second angle signal ( α 2 ) and the third angle signal ( α 3 ) compare with each other to obtain the first angle signal ( α 1 ), the second angle signal ( α 2 ) and the third angle signal ( α 3 Based on this, safety measurements are performed, and it is determined whether they are equal or deviate from each other.

5. The magnetic angle sensor (100) according to claim 4, wherein If the controller determines the first angle signal ( α 1 ), the second angle signal ( α 2 ) and the third angle signal ( α 3 One of the angle signals deviates from the other angle signals by a certain amount. The controller is then configured to detect based on the determined deviation angle signal: One of the first magnetoresistive element (111), the second magnetoresistive element (112), and the third magnetoresistive element (113) generates a faulty output signal, and / or Which of the first magnetoresistive element (111), the second magnetoresistive element (112), and the third magnetoresistive element (113) generates a faulty output signal? 6. The magnetic angle sensor (100) according to claim 1. The controller is configured to operate according to the first differential signal ( d 1 ) and the second differential signal ( d 2 ) and the third differential signal ( d 3 The combination of these signals is used to calculate the fourth angle signal. α 4 ).

7. The magnetic angle sensor (100) according to claim 6. The controller is configured to transfer the first angle signal ( α 1 ), the second angle signal ( α 2 The third angle signal ( α 3 ) and the fourth angle signal ( α 4 They are compared to each other to determine whether they are equal or deviate from each other.

8. The magnetic angle sensor (100) according to claim 7, wherein If the controller determines the first angle signal ( α 1 ), the second angle signal ( α 2 The third angle signal ( α 3 ) and the fourth angle signal ( α 4 One of the angle signals deviates from the other angle signals by a certain amount. The controller is then configured to determine the deviation angle signal as a basis: One of the first magnetoresistive element (111), the second magnetoresistive element (112), and the third magnetoresistive element (113) generates a faulty output signal, and / or Which of the first magnetoresistive element (111), the second magnetoresistive element (112), and the third magnetoresistive element (113) generates a faulty output signal? 9. The magnetic angle sensor (100) according to any one of claims 6 to 8. The controller is configured to use the first differential signal ( d 1 ), the second differential signal ( d 2 ) and the third differential signal ( d 3 Based on this, safety measurements are implemented in the following manner: Checking the first differential signal ( d 1 ) and the third differential signal ( d 3 The first quadratic term and the first differential signal () d 1 ), the second differential signal ( d 2 ) and the third differential signal ( d 3 Is the sum of the second quadratic terms of () a constant? 10. The magnetic angle sensor (100) according to claim 9. The controller is configured to perform the security measurement based on the following equation. in d 1 This represents the first differential signal. d 2 This represents the second differential signal, and d 3 This refers to the third differential signal.

11. The magnetic angle sensor (100) according to claim 1. The first magnetoresistive element (111), the second magnetoresistive element (112), and the third magnetoresistive element (113) include at least one of the following: TMR devices (TMR: tunneling magnetoresistive) GMR devices (GMR: giant magnetoresistance). CMR equipment (CMR: giant magnetoresistance). EMR equipment (EMR: Extra Large Magnetoresistive), and AMR equipment (AMR: Anisotropic magnetoresistance).

12. A method for operating a magnetic angle sensor (100), the method comprising the steps of: A magnetoresistive arrangement (110) is provided having a first magnetoresistive element (111), a second magnetoresistive element (112), and a third magnetoresistive element (113), wherein the first magnetoresistive element (111), the second magnetoresistive element (112), and the third magnetoresistive element (113) are oriented relative to each other in a symmetrical geometric arrangement such that they form a symmetrical arrangement with equal angular distances between them. Based on the positional relationship between the magnetic source (120) and the first magnetoresistive element (111), a first output signal (a) is derived from the first magnetoresistive element (111). Based on the positional relationship between the magnetic source (120) and the second magnetoresistive element (112), a second output signal (b) is derived from the second magnetoresistive element (112). Based on the positional relationship between the magnetic source (120) and the third magnetoresistive element (113), a third output signal (c) is derived from the third magnetoresistive element (113). The three differential signals are determined based on the output signals (a, b, c). d 1 、d 2 、d 3 ),in First differential signal ( d 1 =b–a Based on the combination of the first output signal (a) and the second output signal (b), The second differential signal ( d 2 =c–b Based on the combination of the second output signal (b) and the third output signal (c), and The third differential signal ( d 3 =a–c Based on the combination of the first output signal (a) and the third output signal (c), And based on the three differential signals ( d 1 、d 2 、d 3 To calculate at least three angle signals ( α 1 、α 2 、α 3 ), wherein the three angle signals ( α 1 、α 2 、α 3 Each angle signal in the equation represents the rotation angle of the magnetic source (120) relative to the magnetoresistive arrangement (110), wherein First angle signal ( α 1 According to the first differential signal ( d 1 ) and the second differential signal ( d 2 The combination of ) is calculated, Second angle signal ( α 2 According to the second differential signal ( d 2 ) and the third differential signal ( d 3 The combination of ) is calculated, and Third angle signal ( α 3 According to the first differential signal ( d 1 ) and the third differential signal ( d 3 The combination of ) is used for calculation.

13. A computer-readable digital storage medium having a computer program stored thereon, the computer program having program code for performing the method according to claim 12 when executed on a computer.

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