Angular position sensor system, device, method, and magnetic source

Abstract

An angular position sensor system (100; 300; 600; 1900; 2000) comprising: a magnetic source with at least two circular tracks, including a first circular track (T1) having a first number (M1) of magnetic pole pairs and a second circular track (T2) having a second number (N2) of magnetic pole pairs; a sensor device comprising four magnetic sensors (S1 to S4) each configured for measuring at least one, preferably two magnetic field components; a processing circuit for determining an absolute angular position (θ) based on the measured magnetic field components. A position sensor device (220a; 220b) comprising a PCB and two semiconductor substrates or chips. A method (1400; 1500; 1600; 1700) of determining an absolute angular position. A magnetic source (1810; 1910; 2010; 2110) with two or three circular tracks.

Description

[0001] ANGULAR POSITION SENSOR SYSTEM, DEVICE, METHOD, AND MAGNETIC SOURCE

[0002] Field of the invention

[0003] The present invention relates in general to the field of magnetic sensors, and more in particular to an angular position sensor system, an angular position sensor device, a magnetic source, and methods of determining an angular position.

[0004] Background of the invention

[0005] Magnetic sensor systems, in particular angular position sensor systems are known in the art. They offer the advantage of being able to measure an angular position without making physical contact, thus avoiding problems of mechanical wear, scratches, friction, etc.

[0006] Many variants of position sensor systems exist, addressing one or more of the following requirements: using a simple or cheap magnetic source, using a simple or cheap sensor device, being able to measure over a relatively large range, being able to measure with great accuracy, requiring only simple arithmetic, being able to measure at high speed, being highly robust against positioning errors, being highly robust against an external disturbance field, providing redundancy, being able to detect an error, being able to detect and correct an error, having a good signal-to-noise ratio (SNR), etc.

[0007] Often two or more of these requirements conflict with each other, hence a trade-off needs to be made.

[0008] There is always room for improvements or alternatives.

[0009] Summary of the invention

[0010] It is an object of embodiments of the present invention to provide an angular position sensor system, a position sensor device, a magnetic source, and a method of determining an angular position of a position sensor device relative to a magnetic source.

[0011] It is an object of embodiments of the present invention to provide such a system, device, magnetic source, and method, allowing to determine an angular position with an improved accuracy, e.g. in the presence of an external disturbance field.

[0012] It is an object of embodiments of the present invention to provide such a system, device, magnetic source, and method, which are suitable for use in an industrial, automotive and / or robotic environment.

[0013] It is an object of embodiments of the present invention to provide such a position sensor system, wherein the mounting requirements and / or the mounting tolerances of the sensor device relative to the magnetic source are relaxed.

[0014] It is an object of embodiments of the present invention to provide such a position sensor system, that is more robust against ageing effects, (e.g. related to misalignment, mechanical wear, eccentricity).It is an object of embodiments of the present invention to provide such a position sensor system, requiring a less powerful processor, and / or requiring less processing power, and / or using a simpler algorithm.

[0015] It is an object of embodiments of the present invention to provide such a position sensor system, requiring less storage space (e.g. to store a lower number of coefficients).

[0016] It is an object of embodiments of the present invention to provide a magnetic sensor device and a magnetic source for use in such a position sensor system.

[0017] These and other objectives are accomplished by embodiments of the present invention. According to a first aspect, the present invention provides an angular position sensor system comprising: a magnetic source (e.g. in the form of a single element, e.g. in the form of a single circular element, e.g. in the form of a single magnetic ring or a single magnetic disk or a single cylindrical shape) rotatable about a rotation axis, the magnetic source comprising at least two circular tracks including a first circular track (e.g. Tl) having a first number (e.g. Ml) of magnetic pole pairs for generating a first magnetic field having a first periodicity, and a second and optionally also a third circular track (e.g. T2; T2,T3) having a second number (e.g. N2) of magnetic pole pairs for generating a second magnetic field having a second periodicity different from the first periodicity, wherein a first quotient of the first number (e.g. Ml) divided by a greatest common divisor of the first and the second number (e.g. M1,N2) is an even number and a second quotient of the second number (e.g. N2) divided by the greatest common divisor is an odd number, or vice versa (meaning that the first quotient is an odd number and the second quotient is an even number); a sensor device movable relative to the magnetic source, or vice versa; wherein the sensor device comprises four magnetic sensors including a first, second, third and fourth magnetic sensor (e.g. SI, S2, S3, S4) situated at four different sensor locations (e.g. Pl, P2, P3, P4) in the vicinity of the magnetic source, e.g. above said at least two circular tracks, each magnetic sensor configured for measuring at least one, but preferably two magnetic field components (e.g. two orthogonal magnetic field components) oriented in different directions; wherein the first and the third sensor location (e.g. Pl, P3) are angularly spaced by a first angle with respect to the rotation axis; and wherein the second and the fourth sensor location (e.g. P2, P4) are angularly spaced by a second angle with respect to the rotation axis; wherein one of the first and second sensor location is arranged for measuring the first magnetic field, (e.g. is located above the first track), and the other of the first and second sensor location is arranged for measuring the second magnetic field (e.g. is located above a track different from the first track, e.g. above the second or third track); and wherein one of the third and fourth sensor location is arranged for measuring the first magnetic field (e.g. is located above the first track), and the other of the third and fourth sensor location is arranged for measuring the second magnetic field (e.g. is located above a track different from the first track, e.g. above the second or third track); a processing circuit configured for determining an absolute angular position of the magnetic source relative to the sensor device based on the magnetic field components measured by the fourmagnetic sensors, e.g. for increasing increased accuracy, and / or for reducing cross-talk, and / or without requiring determination of a plurality of coefficients in a calibration procedure.

[0018] One could also say that the magnetic source comprises a "primary track" or "master track" for generating said first magnetic field, and at least one "secondary track" or at least one "nonius track" for generating said second magnetic field.

[0019] In case the magnetic source has three circular tracks, the second track and the third track preferably have the same number N2 of magnetic pole pairs, and the magnetic poles of the second and third track are preferably aligned (e.g. radially aligned in FIG. 3A or FIG. 18A, e.g. axially aligned in FIG. 19 to FIG. 21).

[0020] The first angle may be substantially equal to the second angle, e.g. within a tolerance margin of ±10°, or ±7°, or ±5°, or ±4°, or ±3°, or ±2°, or ±1°.

[0021] In an embodiment, each of said first and second angle is substantially equal to an odd multiple of a straight angle divided by the greatest common divisor, e.g. a product of an odd integer number multiplied by 180° and divided by the greatest common divisor.

[0022] The first angle may be chosen such that the first and the third sensor location (SI, S3) are facing substantially a same magnetic pole phase (e.g. within said tolerance margin of at most ±10°), and the second angle may be chosen such that the second and the fourth sensor location (S2, S4) are facing substantially an opposite magnetic pole phase (e.g. within said tolerance margin of at most ±10°).

[0023] In an embodiment, the processing circuit is configured for determining the absolutely angular position based on an additive combination of the signals measured at the first and the third sensor location (e.g. SI, S3), and based on a subtractive combination of the signals measured at the second the fourth sensor location (e.g. S2, S4), for reducing cross-talk interference.

[0024] In an embodiment, a greatest common divisor of the first number (e.g. Ml) and the second number (e.g. N2) is 1, and the first angle has a value in the range 180° ±10° (or 180° with a smaller tolerance margin of ±7°, or ±5°, or ±4°, or ±3°, or ±2°, or ±1°), and the second angle has a value in the range 180° ±10° (or 180° with a smaller tolerance margin of ±7°, or ±5°, or ±4°, or ±3°, or ±2°, or ±1°). The statement that a greatest common divisor (GCD) of Ml and N2 is 1 is equivalent to the statements "Ml and N2 are coprime numbers, or relatively prime or mutually prime". This offers the advantage that the measurement range is 360°.

[0025] It is an advantage of this sensor system that it has a reduced sensitivity to position offset of the sensor device relative to the magnetic source, or stated in other words, that it has reduced mounting requirements and / or reduced requirements for maximum eccentricity.

[0026] Preferably the magnetic source is a single element, e.g. a single circular magnetic source, e.g. a single magnetic disk (see e.g. FIG. 1(a), FIG. 3(a), FIG. 18A) or a single magnetic cylinder (see e.g. FIG. 19, FIG. 20, FIG. 21). The magnetic source can e.g. be made of a single piece of material which is magnetizedafter its formation, or can e.g. be made by joining (e.g. gluing) multiple rings after they are individually magnetized.

[0027] In an embodiment, the at least two tracks are abutting each other, e.g. radially abutting each other as illustrated in FIG. 1(a) or FIG. 3(a), or e.g. axially abutting each other as illustrated in FIG. 19 to FIG. 21.

[0028] In an embodiment, the magnetic source has at least two circular tracks which are spaced from each other by a non-coded region or by a groove having a width in the range from 0.2 to 1.0 mm.

[0029] In an embodiment, the magnetic source comprises two rings or three rings of magnetic material, spaced from each other by a layer or a zone of a non-magnetic material, such as e.g. plastic or ceramic or a non-magnetic metal or alloy, e.g. aluminum or copper. The non-magnetic material may have a thickness (in the axial direction) of at least 0.5 mm, and / or may have a width (in the radial direction) in the range from about 0.25 mm to 1.5 mm.

[0030] In an embodiment, the two or three rings are separated from each other by means of a groove. In an embodiment, the first and second sensor location (Pl, P2) are spaced apart (e.g. in the radial direction as in FIG. 1, or in the axial direction as in FIG. 19 or FIG. 20) by a distance in the range from 1.0 to 3.0 mm, or in the range from 1.5 mm to 2.5 mm,

[0031] In an embodiment, the third and fourth sensor location (P3, P4) are spaced apart by a distance in the range from 1.0 to 3.0 mm, or in the range from 1.5 mm to 2.5 mm.

[0032] Preferably each of the four magnetic sensors is configured for measuring two orthogonal magnetic field components.

[0033] In an embodiment, see e.g. FIG. 1(a) or FIG. 3(a), one of the magnetic field components measured by the four sensors is oriented in a circumferential direction, (typically denoted By), i.e. tangential to an imaginary circle passing through that sensor location; and another of the orthogonal magnetic field components is oriented in an axial direction (typically denoted Bz), i.e. parallel to the direction of the axis or the shaft.

[0034] In an embodiment, see e.g. FIG. 19 to FIG. 21, one of the magnetic field components measured by the four sensors is oriented in a circumferential direction, (typically denoted By), i.e. tangential to an imaginary circle passing through that sensor location; and another of the orthogonal magnetic field components is oriented in a radial direction (typically denoted Bz), i.e. perpendicular to the rotation axis.

[0035] In an embodiment, the tracks are located in a virtual plane, and the first sensor position (Pl) is spaced from the second sensor position (P2) by a predefined distance (ds or dl2) in the radial direction, and the third sensor position (P3) is spaced from the fourth sensor position(P3) by a predefined distance (ds or d34, preferably substantially equal to dl2) in the radial direction, e.g. as illustrated in FIG. 1(a) or FIG. 3(a) or FIG. 5.

[0036] In an embodiment, the tracks are located on a cylindrical surface, and the first sensor position (Pl) is spaced from the second sensor position (P2) by a predefined distance (dl2) in the axial direction,and the third sensor position (P3) is spaced from the fourth sensor position(P3) by said predefined distance (d34) in the axial direction, preferably substantially equal to dl2, e.g. as illustrated in FIG. FIG. FIG. FIG. 20.

[0037] In an embodiment, the four sensor locations (Pl, P2, P3, P4) are located on a virtual line (X) passing through the centre of the magnetic source, or on a virtual line that is located at a small distance from said centre, e.g. at a distance of at most 10% of the outer radius of the magnetic source, or at most 5%, or at most 4%, or at most 3%, or at most 2%, or at most 1%.

[0038] In an embodiment, the first and the second sensor location (Pl, P2) are located on a first side of said centre, and the third and the fourth sensor location (P3, P4) are located on an opposite side of the centre.

[0039] In an embodiment, the magnetic source has two planar circular tracks in the form of two concentric rings, arranged such that an inner radius (Rl) of the second track (T2) is smaller than an inner radius (R2) of the first track (Tl). An example of such a magnetic source is illustrated in FIG. 1(a).

[0040] The at least two circular tracks are concentric tracks.

[0041] The magnetic source preferably has a planar upper surface.

[0042] Preferably an upper surface of all the tracks are located in a single plane perpendicular to the rotation axis.

[0043] In an embodiment, the magnetic source has three planar circular tracks in the form of three concentric rings, arranged such that an inner radius (Rl) of the second track (T2) is smaller than an inner radius (R2) of the first track (Tl), and the inner radius (R2) of the first track (Tl) is smaller than an inner radius (R3) of the third track (T3). An example of such a magnetic source is illustrated in FIG. 18A.

[0044] The at least three circular tracks are concentric tracks.

[0045] The magnetic source preferably has a planar upper surface.

[0046] Preferably an upper surface of all the tracks are located in a single plane perpendicular to the rotation axis.

[0047] Preferably the magnetic sensors are arranged at a predefined distance "above" the tracks (e.g. in the axial direction in FIG. 1; e.g. in the radial direction in FIG. 19), e.g. at a distance in the range from 0.1 to 5.0 mm, or in the range from 0.3 to 5.0 mm, or in the range from 0.5 to 5.0 mm.

[0048] In an embodiment, the magnetic source has two tracks located on a cylindrical surface about the rotation axis, arranged such that a first centreline (Cl) of the first track (Tl) is situated at a first axial position (al), and a second centreline (C2) of the second track (T2) is situated at a second axial position (a2). An example of such a magnetic source is illustrated in FIG. 19.

[0049] Preferably the two tracks are located in a single virtual cylindrical surface, meaning that they preferably have a same outer diameter.

[0050] In an embodiment, the magnetic source has three tracks located on a cylindrical surface about the rotation axis, arranged such that a first centreline (Cl) of the first track (Tl) is situated at a first axialposition (al), and a second centreline (C2) of the second track (T2) is situated at a second axial position (a2), and a third centreline (C3) of the third track (T3) is situated at a third axial position (a3), wherein the first axial position (al) is located between the second axial position (a2) and the third axial position (a3). An example of such a magnetic source is illustrated in FIG. 20.

[0051] Preferably the three tracks are located in a single virtual cylindrical surface, meaning that they preferably have a same outer diameter.

[0052] In an embodiment where the magnetic source has two or three cylindrical tracks, the sensor device, e.g. semiconductor substrates or sensor chips thereof, may be situated at a predefined distance above the tracks, e.g. in the range from 0.1 to 5.0 mm, or in the range from 0.3 to 5.0 mm, or in the range from 0.5 to 5.0 mm, measured in a direction perpendicular to the rotation axis.

[0053] In an embodiment, one of the first and second number (Ml, N2) is an even number, and the other (N2, Ml) of said first and second number is an odd number.

[0054] In an embodiment, the greatest common divisor of the first number (Ml) and the second number (N2) is equal to 1, and the first number (Ml) of pole pairs is an even number, and the second number (N2) of pole pairs is an odd number. An example of such embodiment is shown in FIG. 1(a) and in FIG. 3(a), where Ml=8 and N2=7.

[0055] In an embodiment, the greatest common divisor of the first number (Ml) and the second number (N2) is equal to 1, and the first number (Ml) of pole pairs is an odd number, and the second number (N2) of pole pairs is an even number. An example of such embodiment is shown in FIG. 6 and FIG. 7 where the magnetic source has a first track (central track) with Ml=7 and a second track (inner track) with N2=8, and a third track (outer track) with N3=N2=8.

[0056] In an embodiment, the greatest common divisor of the first number (Ml) and the second number (N2) is equal to 1, and the first number (Ml) of pole pairs is an odd number, and the second number (N2) of pole pairs is also an odd number. Examples are: (Ml=3 and N2=5) or vice versa; (Ml=5 and N2=7) or vice versa; (Ml=7 and N2=9) or vice versa; (Ml=9 and N2=ll) or vice versa; (Ml=ll and N2=13) or vice versa; (Ml=13 and N2=15) or vice versa; (Ml=15 and N2=17) or vice versa; (Ml=17 and N2=19) or vice versa.

[0057] In an embodiment, Ml=3 and N2=2.

[0058] In an embodiment, Ml=2 and N2=3.

[0059] In an embodiment, each of the numbers Ml, N2 is at least 5 and at most 32.

[0060] In an embodiment, Ml is a number in the range from 7 to 24, e.g. Ml is equal to 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15 or 16 or 17 or 18 or 19 or 20 or 21 or 22 or 23 or 24.

[0061] In an embodiment, the first number is one more than the second number, (thus M1=N2+1). Examples are: Ml=8 and N2=7, or Ml=9 and N2=8, or Ml=10 and N2=9, etc.

[0062] In an embodiment, the first number is one less than the second number, (thus M1=N2-1). Examples are: Ml=7 and N2=8, or Ml=8 and N2=9, or Ml=9 and N2=10, etc.In an embodiment, the first number is two more than the second number, (thus Ml=N2+2). In an embodiment, the first number is two less than the second number, (thus Ml=N2-2). In an embodiment, the first number is three more than the second number, (thus Ml=N2+3). Examples are: Ml=7 and N2=4, or Ml=8 and N2=5, or Ml=10 and N2=7, or Ml=ll and N2=8. In an embodiment, the first number is three less than the second number, (thus Ml=N2-3). Examples are: Ml=4 and N2=7, or Ml=5 and N2=8, or Ml=7 and N2=10, or Ml=8 and N2=ll. In an embodiment, the first number of magnetic pole pairs is a value in the range from 5 to 16. In an embodiment, each of said four sensors is configured for measuring two magnetic field components, and the processing circuit is configured for: e) determining a first linear combination (e.g. a first sum or a first difference) and a second linear combination (e.g. a second sum or a second difference) of two parallel magnetic field components measured by the first and the third magnetic sensor (e.g. SI, S3); and for f) determining a third linear combination (e.g. a third sum or a third difference) and a fourth linear combination (e.g. a fourth sum or a fourth difference) of two parallel magnetic field components measured by the second and the fourth magnetic sensor (e.g. S2, S4); and for g) determining said angular position (9) based on the first, second, third and fourth linear combination. The coefficients of the linear combination may be chosen as values inversely proportional to the amplitudes of each measured component. In this way, the mounting requirements may be further relaxed. For example, the angular position sensor system may become less sensitive to a variation of the distance (also referred to as "air gap") between the magnetic source and the first and second semiconductor substrate, e.g. less sensitive to tilt in the system of FIG. 1, e.g. less sensitive to eccentricity in the system of FIG. 19 or FIG. 20.

[0063] In an embodiment, each of said four sensors is configured for measuring two orthogonal magnetic field components, and the processing circuit is configured for: e) determining a first sum (e.g. suml) and a second sum (e.g. sum2) of two parallel magnetic field components (Bzl,Bz3; Byl, By3) measured by the first and the third magnetic sensor (e.g. SI, S3); and for f) determining a first difference (e.g. diffl) and a second difference (e.g. diff2) of two parallel magnetic field components measured by the second and the fourth magnetic sensor (e.g. S2, S4); and for g) determining said angular position (e.g. 9) based on the first and second sum and based on the first and second difference (diffl, diff2).

[0064] It is an advantage of this arrangement that the angular position can be determined with high accuracy, and in a very simple manner, namely based on two sums and two differences, without using a plurality of coefficients that need to be determined during a calibration procedure.

[0065] It is a major advantage of the arrangement described above, that said sums remove the influence from the magnetic track having an odd number of pole pairs, and that said differences remove the influence from the magnetic track having an even number of pole pairs. Or stated in other words, by using the arrangement as described above, and by combining the sensor signals as described above, the cross-talk between the magnetic tracks can be drastically reduced, e.g. substantially removed in a verysimple manner, without requiring the need for determining the values of a relatively large number of coefficients, e.g. in a calibration procedure.

[0066] In an embodiment, the processing circuit is configured for deriving a first angle value (e.g. 9M) from the first and the second linear combination or from the first and second sum (e.g. suml, sum2); and the processing circuit is configured for deriving a second angle value (e.g. 0N) from the third and fourth linear combination or from the first and the second difference (e.g. diffl, diff2); and the processing circuit is configured for determining the angular position (e.g. 9) based on the first and the second angle value (e.g. 9M, 9N).

[0067] The processing circuit may be configured for deriving a first set of quadrature components based on the first and second sum, e.g. by amplitude and / or phase correction, and / or by calculating each of these quadrature components as a weighted sum of suml and sum2; and for determining a second set of quadrature components based on the first and second difference, e.g. by amplitude and / or phase correction, and / or by calculating each of these quadrature components as a weighted sum of diffl and diff2; and for deriving said first angle (9M) from the first set of quadrature components, and for deriving said second angle (9N) from the second set of quadrature components. The weighting factors may be predefined values which are stored in a non-volatile memory during a calibration procedure, or may be determined automatically during actual use of the system.

[0068] In an embodiment, the processing circuit is configured for finding two integer values KI and K2 for which a difference between a first value calculated as (9M+K1*36O°) / M1 and a second value calculated as (9N+K2*360°) / N2 is smaller than a predefined threshold, and for assigning said first value or said second value or a weighted average of said first value and said second value to the angular position 9.

[0069] In an embodiment, the magnetic source comprises only two tracks (e.g. Tl, T2); and wherein the first sensor (e.g. SI) and the third sensor (e.g. S3) are located above the first track (e.g. Tl), preferably above a centreline (e.g. Cl) of the first track; and wherein the second sensor (e.g. S2) and the fourth sensor (e.g. S4) are located above the second track (e.g. T2), preferably above a centreline (e.g. C2) of the second track.

[0070] An example of this embodiment is illustrated in FIG. 1(a) and FIG. 19.

[0071] In this embodiment, the first and the third sensor location (Pl, P3) are preferably located symmetrically with respect to the centre of the magnetic source, and the second and the fourth sensor location (P2, P4) are preferably located symmetrically with respect to the centre of the magnet. In other words, the centre of the magnet is preferably situated in the middle between Pl and P3, and in the middle between P2 and P4.

[0072] In an embodiment, the magnetic source further comprises a third track (e.g. T3) arranged such that the first track (e.g. Tl) is located between the second track (e.g. T2) and the third track (e.g. T3).

[0073] An example of this embodiment is illustrated in FIG. 3(a) and in FIG. 6, and in FIG. 20.In this embodiment, the first track (e.g. Tl) can also be referred to as the "central track". In FIG. 3 and in FIG. 6 the second track (e.g. T2) can also be referred to as the "inner track", and the third track (e.g. T3) can also be referred to as the "outer track".

[0074] The third track has the same number of magnetic poles as the second track.

[0075] In the embodiment of FIG. 3(a) to FIG. 5, the first and third sensor (e.g. SI, S3) are located above the first track, the second sensor (e.g. S2) is located above the second track, and the fourth sensor (e.g. S4) is located above the third track, the first and the third sensor location are located symmetrically with respect to the rotation axis, but the second and the fourth sensor location are located asymmetrically with respect to the rotation axis. For example, in FIG. 3(a), S2 is located closer to the rotation axis than S4.

[0076] In the embodiment of FIG. 6 and FIG. 7, the second and fourth sensor are located above the first track, the first sensor is located above the second track, and the third sensor is located above the third track, the second and the fourth sensor location are located symmetrically with respect to the rotation axis, but the first and the third sensor location are located asymmetrically with respect to the rotation axis.

[0077] It is an advantage of this system that if offers an improved robustness against magnet eccentricity and / or wobble and / or mounting tolerances.

[0078] In an embodiment, the first and the third sensor (e.g. SI, S3) are situated on the first track (e.g. Tl), the second sensor (e.g. S2) is situated on the second track (e.g. T2), and the fourth sensor (e.g. S4) is situated on the third track (e.g. T3). An example of this embodiment is illustrated in FIG. 3(a) to FIG. 5.

[0079] In an embodiment, the second and the fourth sensor (e.g. S2, S4) are situated on the first track (e.g. Tl), the first sensor (e.g. SI) is situated on the second track (e.g. T2), and the third sensor (e.g. S3) is situated on the third track (e.g. T3). An example of this embodiment is illustrated in FIG. 6 to FIG. 7.

[0080] In an embodiment, the first and the second magnetic sensor (e.g. SI, S2) are integrated in a first semiconductor substrate, and the third and the fourth magnetic sensor (e.g. S3, S4) are integrated in a second semiconductor substrate.

[0081] In an embodiment, the sensor device comprises a printed circuit board and two semiconductor substrates or two sensor chips, and the semiconductor substrates or sensor chips are situated between the printed circuit board and the magnetic source. This offers the advantage that the sensors can be located closer to the magnetic source, that the measured signals can be larger, the signal-to-noise ratio can be improved, and accuracy can be improved.

[0082] In an embodiment, the sensor device comprises a printed circuit board and two semiconductor substrates or two sensor chips, and the printed circuit board is situated between the magnetic source and the semiconductor substrates or the sensor chips.

[0083] In an embodiment, the first and second magnetic sensor (e.g. SI, S2) are incorporated in a first packaged semiconductor device (also referred to as "first chip"), and the third and fourth magneticsensor (e.g. S3, S4) are incorporated in a second packaged semiconductor device (also referred to as "second chip").

[0084] In an embodiment, the first and second packaged semiconductor device are mounted on a single printed circuit board.

[0085] The single PCB may have a U-shape for allowing passage of a shaft, (e.g. as illustrated in FIG. 4). In an embodiment, the first track (e.g. Tl) has a first track width "wl" in the range of 2.0 to 4.0 mm, or in the range from 2.25 to 3.75 mm, or in the range from 2.50 to 3.50 mm, or in the range from 2.75 to 3.25 mm. The track width may be measured in the radial direction of the magnetic source, i.e. perpendicular to the rotation axis (e.g. as in FIG. 1 to FIG. 7), or may be measured in an axial direction of the magnetic source, i.e. parallel to the rotation axis (as in FIG. 19 or FIG. 20).

[0086] In an embodiment, the second track has a second track width w2 substantially equal to the first track width wl, within a tolerance margin of ±25% or ±20% or ±15% or ±10%.

[0087] In an embodiment, the second track has a second track width w2 smaller than the first track width wl.

[0088] In an embodiment, a ratio W2 / W1 of the second track width over the first track width is a value in the range from 15% to 70%, or 15% to 60%, or 15% to 50%, or 15% to 40%, or 15% to 30%.

[0089] In an embodiment, the magnetic source has three circular tracks, and the first track width is a value in the range from 2.0 to 4.0 mm, and each of the second track and the third track has a width in the range from 0.50 to 1.5 mm, or in the range from 0.70 to 1.3 mm, or in the range from 0.75 to 1.25 mm.

[0090] In an embodiment, at least two of the four magnetic sensors are located substantially in the middle of one of the tracks (i.e. "above one of the centrelines of the tracks).

[0091] In an embodiment, the four magnetic sensor are located substantially in the middle of one of the tracks (i.e. "above one of the centrelines of the tracks).

[0092] The first sensor location (Pl) and the second sensor location (P2) are preferably spaced in the radial direction by a distance dl2 in the range from 1.0 to 3.0 mm, or in the range from 1.25 to 2.75 mm, or in the range from 1.5 to 2.5 mm, or in the range from 1.75 to 2.25 mm; and the third and the fourth sensor location (P3, P4) are preferable spaced by a distance d34, preferably equal to dl2.

[0093] In an embodiment, Ml=14 pole pairs, and N2=13 pole pairs, and the magnetic source has three magnetic tracks, and an inner diameter in the range from 25 mm to 50 mm, or from 25 to 45 mm, and an outer diameter that is 8.0 to 14 mm larger than the inner diameter.

[0094] In an embodiment, each of the first, second, third and fourth sensor (e.g. SI, S2, S3, S4) comprises an integrated magnetic concentrator (IMC) disk and two horizontal Hall elements arranged near a periphery of the disk, angularly spaced by 180°. For example as illustrated in FIG. 1(b), FIG. 3(b) and FIG. 10.In an embodiment, each of the first, second, third and fourth sensor comprises a horizontal Hall element and one vertical Hall element. For example as illustrated in FIG. 1(c), FIG. 3(c) and FIG. 11.

[0095] In an embodiment, each of the first, second, third and fourth sensor comprises a horizontal Hall element and two vertical Hall elements, arranged on opposite sides of the horizontal Hall element.

[0096] According to a second aspect, the present invention also provides a sensor device, comprising: four magnetic sensors including a first, second, third and fourth magnetic sensor (e.g. SI, S2, S3, S4), situated at four different sensor locations (e.g. Pl, P2, P3, P4) situated on a virtual line (e.g. X), each magnetic sensor configured for measuring two orthogonal magnetic field components; wherein a distance between the first and second sensor location (e.g. Pl, P2) is a value in the range from 1.0 to 3.0 mm, and a distance between the third and fourth sensor location (e.g. P3, P4) is a value in the range from 1.0 to 3.0 mm, and a distance between the first and the third sensor location (e.g. Pl, P3) is at least 25 mm, e.g. a value in the range from 30 to 60 mm; a processing circuit configured for e) determining a first sum (e.g. suml) and a second sum (e.g. sum2) of two parallel magnetic field components measured by the first and the third magnetic sensor (e.g. SI, S3); and for f) determining a first difference (e.g. diffl) and a second difference (e.g. diff2) of two parallel magnetic field components measured by the second and the fourth magnetic sensor (e.g. S2, S4); and forg) determining an angular position (9) based on the first and second sum (e.g. suml, sum2) and based on the first and second difference (e.g. diffl, diff2).

[0097] This magnetic sensor device may comprise a printed circuit board (PCB) and two semiconductor devices ("chips") mounted to the PCB, communicatively interconnected via a serial bus (e.g. an SPI bus). In this case, the processing circuit may be implemented inside one (or both) of the sensor devices, e.g. as illustrated in FIG. 12, but the present invention is not limited hereto, and in another embodiment, e.g. as illustrated in FIG. 13, the PCB may optionally further comprise an external processor communicatively connected to each of the two sensor devices. In this case, the processing circuit may be part of the external processor.

[0098] According to a third aspect, the present invention also provides a method of determining an angular position of a magnetic source relative to a sensor device, wherein the sensor device comprises a first, second, third and fourth magnetic sensor (e.g. SI, S2, S3, S4) located at four sensor locations (e.g. Pl, P2, P3, P4 respectively); wherein the magnetic source is rotatable about a rotation axis and comprises at least two circular tracks (e.g. two track T1,T2, or e.g. three tracks T1,T2,T3) including a first circular track (e.g. Tl) having a first number (e.g. Ml) of magnetic pole pairs for generating a first magnetic field having a first periodicity, and a second circular track (e.g. T2) and optionally also a third circular track (e.g. T3) having a second number (e.g. N2) of magnetic pole pairs for generating a second magnetic field having a second periodicity; wherein a first quotient of the first number divided by a greatest common divisor of the first and the second number (e.g. M1,N2) is an even number, and a second quotient of the second number divided by said greatest common divisor is an odd number, or vice versa; the method comprising the steps of: a) measuring by the sensor device at least one magnetic field component of thefirst magnetic field at two positions around the rotation axis, one angularly spaced from the other by a first angle with respect to the rotation axis; c) measuring by the sensor device at least one magnetic field component of the second magnetic field at two positions around the rotation axis, one angularly spaced from the other by a second angle with respect to the rotation axis; g) determining an angular position (e.g. 9) based on the measured magnetic field components.

[0099] In an embodiment the first angle may be an angle in the range 180° ±10°, and the second angle may be an angle in the range 180° ±10°.

[0100] In an embodiment, the method comprises the steps of: a) measuring by the first and the second magnetic sensor (e.g. SI, S2) at least one magnetic field component of the first magnetic field at the first sensor location (e.g. Pl), and measuring at least one magnetic field component of the second magnetic field at the second sensor location (e.g. P2); c) measuring by the third and the fourth magnetic sensor (e.g. S3, S4) at least one magnetic field component of the first magnetic field at one of said third and fourth sensor location (e.g. P3, P4), and measuring at least one magnetic field component of the second magnetic field at the other of said third and fourth sensor location (e.g. P3, P4); g) determining an angular position (e.g. 9) based on the measured magnetic field components.

[0101] A flowchart of this method is illustrated in FIG. 14. Preferably one of the numbers Ml, N2 is an even number, and the other number is an odd number.

[0102] In an embodiment, each of said first and second angle are substantially equal to a product of an odd integer number multiplied by 180° and divided by the greatest common divisor.

[0103] In an embodiment, step g) comprises: combining said measured magnetic field components of the first magnetic field at said two positions to produce a first track signal; and combining said measured magnetic field components of the second magnetic field at said two positions to produce a second track signal; and determining said angular position (9) based on said first and second track signal.

[0104] In an embodiment, the greatest common divisor is equal to 1.

[0105] In an embodiment, the first and the second number (e.g. Ml, N2) are co-prime numbers, preferably one being an even number, and the other being an odd number.

[0106] According to a fourth aspect, the present invention also provides a method of determining an angular position of a magnetic source relative to a sensor device, wherein the sensor device comprises a first, second, third and fourth magnetic sensor (e.g. SI, S2, S3, S4) located at four sensor locations (e.g. Pl, P2, P3, P4 respectively), optionally located on a virtual line that passes through the centre of the magnetic source or that is located at a small distance from said centre, or optionally such that Pl and P2 are located on a first virtual line parallel to the rotation axis, and P3 and P4 are located on a second virtual line parallel to the rotation axis; wherein the magnetic source is rotatable about a rotation axis and comprises two concentric circular tracks (e.g. Tl, T2), including a first circular track (e.g. Tl) having a first number (e.g. Ml) of magnetic pole pairs, and a second circular track (e.g. T2) having a second number (e.g. N2) of magnetic pole pairs, the first and second number being co-prime numbers,preferably one even number and one odd number; the method comprising the steps of: a) measuring by said first magnetic sensor (e.g. SI) two (e.g. orthogonal) magnetic field components at a first sensor location (e.g. Pl) situated above the first track (e.g. Tl); b) measuring by said second magnetic sensor (e.g. S2) two (e.g. orthogonal) magnetic field components at a second sensor location (e.g. P2) situated above the second track (e.g. T2); c) measuring by said third magnetic sensor (e.g. S3) two (e.g. orthogonal) magnetic field components at a third sensor location (e.g. P3) situated on the first track (e.g. Tl); d) measuring by said fourth magnetic sensor (e.g. S4) two (e.g. orthogonal) magnetic field components at a fourth sensor location situated above the second track; g) determining an angular position (e.g. 9) based on the measured magnetic field components. A flow-chart of this method is shown in FIG. 15, see also FIG. 2A and FIG. 2B.

[0107] According to a fifth aspect, the present invention also provides a method of determining an angular position of a magnetic source relative to a sensor device; wherein the sensor device comprises a first, second, third and fourth magnetic sensor (e.g. SI, S2, S3, S4) located at four sensor locations (e.g. Pl, P2, P3, P4), optionally located on a virtual line that passes through the centre of the magnetic source or that is located at a small distance from said centre, or optionally Pl and P2 being located on a first virtual line parallel to the rotation axis, and P3 and P4 being located on a second virtual line parallel to the rotation axis; wherein the magnetic source is rotatable about a rotation axis and comprises at least three circular tracks including a first (e.g. central) track (e.g. Tl) having a first number (e.g. Ml) of magnetic pole pairs, and a second (e.g. inner) track (e.g. T2) and a third (e.g. outer) track (e.g. T3) both having a second number (e.g. N2) of magnetic pole pairs, the first and second number (e.g. Ml, N2) being co-prime numbers, preferably one even number and one odd number; the method comprising the steps of: a) measuring by the first magnetic sensor (e.g. SI) two (e.g. orthogonal) magnetic field components (e.g. Byl, Bzl) at the first sensor location (e.g. Pl) above the first track (e.g. Tl); b) measuring by the second magnetic sensor (e.g. S2) two (e.g. orthogonal) magnetic field components (e.g. By2, Bz2) at the second sensor location (e.g. P2) above the second track (e.g. T2); c) measuring by the third magnetic sensor (e.g. S3) two (e.g. orthogonal) magnetic field components (e.g. By3, Bz3) at the third sensor location (e.g. P3) above the first track (e.g. Tl); d) measuring by the fourth magnetic sensor (e.g. S4) two (e.g. orthogonal) magnetic field components (e.g. By4, Bz4) at the fourth sensor location (e.g. P4) above the third track (e.g. T3); g) determining an angular position (e.g. 9) based on the measured magnetic field components. A flow-chart of this method is shown in FIG. 16, see also FIG. 5.

[0108] According to a sixth aspect, the present invention also provides a method of determining an angular position of a magnetic source relative to a sensor device, wherein the sensor device comprises a first, second, third and fourth magnetic sensor (e.g. SI, S2, S3, S4) located at four sensor locations (e.g. Pl, P2, P3, P4), optionally located on a virtual line that passes through the centre of the magnetic source or that is located at a small distance from said centre, or optionally Pl and P2 being located on a first virtual line parallel to the rotation axis, and P3 and P4 being located on a second virtual line parallel tothe rotation axis; wherein the magnetic source is rotatable about a rotation axis and comprises at least three circular tracks including a first (e.g. central) track (e.g. Tl) having a first number (e.g. Ml) of magnetic pole pairs, and a second (e.g. inner) track (e.g. T2) and a third (e.g. outer) track (e.g. T3) both having a second number (e.g. N2) of magnetic pole pairs, the first and second number (e.g. Ml, N2) being co-prime numbers, preferably one even number and one odd number; the method comprising the steps of: a) measuring by the first magnetic sensor (e.g. SI) two (e.g. orthogonal) magnetic field components (e.g. Byl, Bzl) at the first sensor location (e.g. Pl) above the second track (e.g. T2); b) measuring by the second magnetic sensor (e.g. S2) two (e.g. orthogonal) magnetic field components (e.g. By2, Bz2) at the second sensor location (e.g. P2) above the first track (e.g. Tl); c) measuring by the third magnetic sensor (e.g. S3) two (e.g. orthogonal) magnetic field components (e.g. By3, Bz3) at the third sensor location (e.g. P3) above the third track (e.g. T3); d) measuring by the fourth magnetic sensor (e.g. S4) two (e.g. orthogonal) magnetic field components (e.g. By4, Bz4) at the fourth sensor location (e.g. P4) above the first track (e.g. Tl); g) determining an angular position (e.g. 9) based on the measured magnetic field components. A flow-chart of this method is shown in FIG. 17, see also FIG. 7.

[0109] In an embodiment of the third, fourth, fifth or sixth aspect, the magnetic source is rotatable about a rotation axis and comprises at least two circular tracks including a first circular track (e.g. Tl) having a first number (e.g. Ml) of magnetic pole pairs for generating a first magnetic field having a first periodicity, and a second circular track (e.g. T2) and optionally also a third circular track (e.g. T3) having a second number (e.g. N2) of magnetic pole pairs for generating a second magnetic field having a second periodicity, the first and second number (e.g. Ml, N2) being co-prime numbers, preferably one even number and one odd number; and the method comprising the steps of: a) measuring by the first and the second magnetic sensor (e.g. SI, S2) at least one magnetic field component of the first magnetic field at one of said first and second sensor location (e.g. P1,P2), and measuring at least one magnetic field component of the second magnetic field at the other of said first and second sensor location (e.g. Pl, P2); c) measuring by the third and the fourth magnetic sensor (e.g. S3, S4) at least one magnetic field component of the first magnetic field at one of said third and fourth sensor location (e.g. P3, P4), and measuring at least one magnetic field component of the second magnetic field at the other of said third and fourth sensor location (e.g. P3, P4); g) determining an angular position (e.g. 9) based on the measured magnetic field components.

[0110] In an embodiment of the third, fourth, fifth or sixth aspect, two magnetic field components are measured at each of said four sensor locations (e.g. Pl, P2, P3, P4), and the method further comprises the following steps: e) determining a first and a second linear combination for each pair of parallel magnetic field components measured by the first and third magnetic sensor (e.g. SI, S3); f) determining a third and a fourth linear combination for each pair of parallel magnetic field components measured by the second and fourth magnetic sensor (e.g. S2, S4); and step g) comprises: determining said angular position (9) based on the first, second, third and fourth linear combination.In an embodiment of the third, fourth, fifth or sixth aspect, two orthogonal magnetic field components are measured at each of said four sensor locations (e.g. Pl, P2, P3, P4), and the method further comprising the following steps: e) determining a first and a second sum (e.g. suml, sum2) for each pair of parallel magnetic field components measured by the first and third magnetic sensor (e.g. SI, S3); f) determining a first and a second difference (e.g. diffl, diff2) for each pair of parallel magnetic field components measured by the second and fourth magnetic sensor (e.g. S2, S4); and step g) comprises: determining said angular position (e.g. 9) based on the first and second sum (e.g. suml, sum2) and based on the first and second difference (e.g. diffl, diff2).

[0111] In an embodiment, step e) further comprises: matching an amplitude and / or a phase of the first and the second sum (e.g. suml, sum2), and determining said first angle value (e.g. 9M) as a function (e.g. an arctangent function) of a ratio of the first and second sum; and step f) further comprises: matching an amplitude and / or a phase of the first and the second difference (e.g. diffl, diff2), and determining said second angle value (e.g. 9N) as a function (e.g. an arctangent function) of a ratio of the first and second difference. The amplitude and / or phase matching may be performed using the Lissajous approach or Lissajous technique.

[0112] In an embodiment, step g) comprises: finding two integer values KI, K2 for which a first value calculated as (9M+K1*36O°) / M1 is closest to a second value calculated as (9N+K2*360°) / N2, and assigning the first value or the second value or a weighted average of the first value and the second value to the angular position 9.

[0113] According to a seventh aspect, the present invention also provides a magnetic source comprising three circular tracks (e.g. Tl, T2, T3) including a first track (e.g. Tl), a second track (e.g. T2) and a third track (e.g. T3); wherein the first track (e.g. Tl) is located between the second track (e.g. T2) and the third track (e.g. T3); wherein the first track (e.g. Tl) has a first number (e.g. Ml) of magnetic pole pairs; wherein each of the second and third track (e.g. T2, T3) has a second number (e.g. N2) of magnetic pole pairs; wherein the magnetic poles of the second and the third track (e.g. T2, T3) are radially or axially aligned; wherein a greatest common divisor of the first and the second number (e.g. Ml, N2) is 1.

[0114] In an embodiment, one of the first and second number (e.g. Ml, N2) is an even number, and the other of said first and second number (e.g. N2, Ml) is an odd number.

[0115] In an embodiment, the three circular tracks are concentric rings, arranged such that an inner radius (e.g. Rl) of the second track (e.g. T2) is smaller than an inner radius (e.g. R2) of the first track (e.g. Tl), and the inner radius (e.g. R2) of the first track (e.g. Tl) is smaller than an inner radius (e.g. R3) of the third track (e.g. T3). An example of such a magnetic source is illustrated in FIG. 18A. Preferably a surface of the three tracks are co-planar.

[0116] In an embodiment, the three circular tracks are cylindrical tracks about said rotation axis, arranged such that a first centreline (e.g. Cl) of the first track (e.g. Tl) is situated at a first axial position(e.g. al), and a second centreline (e.g. C2) of the second track (e.g. T2) is situated at a second axial position (e.g. a2), and a third centreline (e.g. C3) of the third track (e.g. T3) is situated at a third axial position (e.g. a3), wherein the first axial position (e.g. al) is located between the second axial position (e.g. a2) and the third axial position (e.g. a3). An example of such a magnetic source is illustrated in FIG. 20 and FIG. 21. Preferably the three tracks are located in a single virtual cylindrical surface, meaning that they preferably have a same outer diameter.

[0117] The first circular track has a fixed angular offset relative to the second track, and thus also to the third track. This angular offset may be a known, predefined value (e.g. 0°), or may be an unknown, pseudo-random value, depending on how the magnetic source is produced.

[0118] In an embodiment, the magnetic source is produced in a manner such that this angular offset is smallerthan 3°, or smallerthan 2°, orsmallerthan 1°, as illustrated by the dotted ellipse in the example of FIG. 18A.

[0119] The magnetic source may be or may comprise one or more permanent magnetic rings, or may be formed as a monolithic piece of magnetic material, or may be composed of two or three monolithic pieces of magnetic material.

[0120] In an embodiment, the tracks are planar tracks, and each of said first, second and third track is axially magnetized, e.g. as illustrated in FIG. 18B).

[0121] In an embodiment, the tracks are planar tracks, and each of said first, second and third track is axial-lateral (AL) magnetized, or tangentially magnetized, e.g. as illustrated in FIG. 18C.

[0122] In an embodiment, the tracks are cylindrical tracks, and each of said first, second and third track is radially magnetized, or tangentially magnetized, e.g. Figs.19 and 20.

[0123] In an embodiment, the tracks are planar tracks, and the inner and outer track are axially magnetized, and the central track is axial-lateral (AL) or tangentially magnetized.

[0124] In an embodiment, the central track is axially magnetized, and the inner and outer track are axial-lateral (AL) or tangentially magnetized.

[0125] In an embodiment, the first track (Tl) has a first width "wl", the second track (T2) has a second width "w2", and the third track (T3), if present, has a third width "w3", and wl is larger than w2, and wl is larger than w3, or written mathematically: (wl>w2) and (wl>w3).

[0126] In an embodiment, (w2 / w3) is a value in the range from 0.75 to 1.25, or in the range from 0.80 to 1.20, or in the range from 0.90 to 1.10.

[0127] In an embodiment, (wl / w2) > 1.25 and (wl / w3) > 1.25.

[0128] In an embodiment, (wl / w2) > 1.5 and (wl / w3) > 1.5.

[0129] In an embodiment, (wl / w2) > 1.75 and (wl / w3) > 1.75.

[0130] In an embodiment, (wl / w2) > 2.0 and (wl / w3) > 2.0.

[0131] In an embodiment, (wl / w2) > 2.5 and (wl / w3) > 2.5.In an embodiment, wl is a value in the range of 2.0 to 4.0 mm, or in the range from 2.25 to 3.75 mm, or in the range from 2.50 to 3.50 mm, or in the range from 2.75 to 3.25 mm.

[0132] In an embodiment, a ratio (w2 / wl) is a value in the range from 15% to 70%, or 15% to 60%, or 15% to 50%, or 15% to 40%, or 15% to 30%.

[0133] In an embodiment, wl is a value in the range from 2.0 to 4.0 mm, and each of w2 and w3 is a value in the range from 0.50 to 1.5 mm, or in the range from 0.75 to 1.25 mm.

[0134] In an embodiment, M1=(N2+1), or M1=(N2-1), or Ml=(N2+3), or Ml=(N2-3).

[0135] In an embodiment, the magnetic source has an inner diameter (i.e. the inner diameter of the second track) in the range from 25 mm to 50 mm, and an outer diameter (i.e. the outer diameter of the third track) that is 8 mm to 14 mm larger than the inner diameter.

[0136] In an embodiment, Ml=14 pole pairs, and N2=13 pole pairs, and the magnetic source has an inner diameter in the range from 25 mm to 50 mm, and an outer diameter that is 8 mm to 14 mm larger than the inner diameter.

[0137] In an embodiment, Ml=13 pole pairs, and N2=14 pole pairs, and the magnetic source has an inner diameter in the range from 25 mm to 50 mm, and an outer diameter that is 8 mm to 14 mm larger than the inner diameter; and preferably wherein the magnetic poles of the second track and of the third track (e.g. T2, T3) are radially aligned (e.g. if the tracks are planar tracks) or axially aligned (e.g. if the tracks are cylindrical tracks).

[0138] According to an eighth aspect, the present invention also provides an angular position sensor system for determining an angular position of a magnetic source relative to a sensor device, the system comprising: a magnetic source rotatable about a rotation axis, the magnetic source comprising at least two circular tracks (e.g. T1,T2; T1,T2,T3), including a first circular track (e.g. Tl) having a first number (e.g. Ml) of magnetic pole pairs for generating a first magnetic field having a first magnetic field pattern periodicity with respect to said rotation axis , and a second circular track (e.g. T2) and optionally also a third circular track (e.g. T3) having a second number (e.g. N2) of magnetic poles pairs for generating a second magnetic field having a second magnetic field pattern periodicity with respect to said rotation axis; wherein a first quotient of the first number (e.g. Ml) divided by a greatest common divisor of the first and the second number (e.g. M1,N2) is an even number and a second quotient of the second number (e.g. N2) divided by the greatest common divisor is an odd number, or vice versa (meaning that the first quotient is an odd number and the second quotient is an even number); a sensor device movable relative to the magnetic source, or vice versa; wherein the sensor device comprises four magnetic sensors including a first, second, third and fourth magnetic sensor (e.g. SI, S2, S3, S4) situated at four different sensor locations (e.g. Pl, P2, P3, P4), each magnetic sensor configured for measuring at least one but preferably two magnetic field components oriented in different directions (e.g. Byl,By2,By3,By4; or Byl,Bzl,By2,Bz2,By3,Bz3,By4,Bz4); wherein the first and the third sensor location (e.g. Pl, P3) are angularly spaced by a first angle with respect to the rotation axis; and wherein thesecond and the fourth sensor location (e.g. P2, P4) are angularly spaced by a second angle with respect to the rotation axis; each of said first and second angle being substantially equal to a product of an odd integer number multiplied to 180° divided by the greatest common divisor; wherein one of the first and second sensor location (e.g. Pl, P2) is arranged for measuring the first magnetic field, and the other of the first and second sensor location (e.g. P2, Pl) is arranged for measuring the second magnetic field; wherein one of the third and fourth sensor location (e.g. P3, P4) is arranged for measuring the first magnetic field, and the other of the third and fourth sensor location (e.g. P4, P3) is arranged for measuring the second magnetic field; a processing circuit configured for determining an absolute angular position (e.g. 9) of the magnetic source relative to the sensor device based on the magnetic field components (e.g. Byl,By2,By3,By4; Byl,Bzl,By2,Bz2,By3,Bz3,By4,Bz4) measured by the four magnetic sensors (e.g. SI, S2, S3, S4).

[0139] In one particular embodiment, the angular position sensor system may comprise a magnetic source (preferably in the form of a single circular magnetic source, e.g. a circular disk or a cylinder) rotatable about a rotation axis and comprising at least two circular tracks (e.g. two tracks or three tracks) including : one or more first circular tracks having a same first number of magnetic pole pairs for generating a first magnetic field having a first magnetic field pattern periodicity with respect to said rotation axis , and one or more second circular tracks having a same second number of magnetic poles pairs for generating a second magnetic field having a second magnetic field pattern periodicity with respect to said rotation axis; wherein a first quotient (e.g. ql) of the first number divided by a greatest common divisor of the first and the second number (e.g. Ml, N2) is an even number and a second quotient (e.g. q2) of the second number divided by the greatest divisor is an odd number. The angular position sensor system may comprise a sensor device movable relative to the magnetic source, or vice versa.

[0140] In a first variant of the embodiment, the sensor device of the angular position sensor system may comprise a first magnetic sensor located at a first sensor location, and a third magnetic sensor located at a third sensor location, each magnetic sensor configured to measure at least one but preferably two magneticfield components oriented in different directions. The third sensor location may be angularly spaced away from the first sensor location by a first angle with respect to the rotation axis so as the third sensor location may be, with respect to the first location, in correspondence with (e.g. in front, above, near, at) a same magnetic poles phase of one of the first and the second circular track(s) and in correspondence with an opposite magnetic poles phase of the other of the first and the second circular tracks. Preferably, the first magnetic sensor may be on or facing to (e.g. located in front of, toward) a surface of the magnetic source covering both a first magnetic pole phase of said first circular track(s) and a second magnetic pole phase of the second circular track(s), while the third magnetic sensor may facing to another surface of the magnetic source covering a same of one of the first and the second magnetic poles phase and the opposite of the other one of the first and the second magnetic polesphase. In such arrangement. The system may thus comprise a processing circuit configured for determining an absolute angular position (9) of the magnetic source relative to the sensor device based on : an additive combination of the magnetic field components measured by the first and the third magnetic sensors e.g. for providing a first signal indicative of the sensed pole phase of one of the first and the second circular track(s), and a subtractive combination of the magnetic field components measured by the first and the third magnetic sensors e.g. for providing a second signal indicative of the sensed magnetic pole phase of the other one of the first and the second circular track(s).

[0141] In a second variant of the embodiment, the sensor device of the angular position sensor system may comprise a first magnetic sensor located at a first sensor location, a second magnetic sensor located at a second sensor location, a third magnetic sensor located at a third sensor location, and a fourth sensor located at a fourth sensor location, each magnetic sensor configured to measure at least one but preferably two magneticfield components oriented in different directions. The third sensor location may be angularly spaced away from the first sensor location by a first angle with respect to the rotation axis so as to be, with respect to the first sensor location, in correspondence with (e.g. in front, above, near, at, axially or radially aligned) a same magnetic pole phase of one of the first and the second circular track(s) and with an opposite magnetic pole phase of the other one of the first and the second circular track(s). The fourth sensor location may be angularly spaced away from the second sensor location by a second angle with respect to the rotation axis so as to be, with respect to the second sensor location, in correspondence with a same magnetic pole phase of one of the first and the second circular track(s) and with an opposite magnetic pole phase of the other one of the first and the second circular track(s). Preferably, the first and the third sensor may be located on or facing to one(s) of the first circular track(s) and the second circular track(s), while the second and the fourth sensor may be located on or facing to the other one(s) of the first circular track(s) and the second circular track(s). In some arrangement, notably depending on the magnetic source configuration, the second angle can correspond or differ to the first angle, and / or the first sensor location can be axially or radially aligned with one of the second and fourth sensor location, and / or the third sensor location can be axially or radially aligned with the other one of the second and fourth sensor location. The angular position sensor system may then comprise a processing circuit configured for determining an absolute angular position (9) of the magnetic source relative to the sensor device based on an additive or substantive combination of the magnetic field components measured by first and the third magnetic sensors e.g. for providing a first signal (e.g. track signal) indicative of the sensed magnetic poles phase of one of the first and the second circular track(s) with reduced cross-talk interferences from the other circular tracks, and on an additive or subtractive combination of the magnetic field components measured by the second and forth magnetic sensor e.g. for providing a second signal (e.g. second track signal) indicative of the sensed magnetic poles phase of the other of the first and second circular track(s) with reduced cross-talk interferences. Preferably, each of the first and the third magnetic sensor may substantially (e.g. within a tolerancemargin of at most ±10°) facing one of said one or more first circular tracks, while each of the second and the fourth sensor may substantially (e.g. within a tolerance margin of at most ±10°) facing one of said one or more second circular tracks, e.g. for being less sensitive to cross-talk.

[0142] The effect of these sensor locations arrangements is to dispose of couples of sensor signals, each comprising one similar signal indicative of a first (periodic) position of the magnetic source as well as one opposite ( e.g. inversed) signal indicative of a second (periodic) position of the magnetic source. By an additive or subtractive combination of such couple of signals, the unwanted signal (e.g. crosstalk) can be reduced, or even removed from the combined signal. Moreover, by facing the couple of sensors on selected track, the interference of the unwanted signal can be further reduced in the combined signal.

[0143] The absolute angular position of the magnetic source relative to the sensor device may be thus determined based on such couple of signals indicative of a first and a second angular position of the magnetic source, e.g. by using a Vernier or Master-Nonius calculation or approach, or by using one of the first and second angular position for discriminating the period of the other one the first and second angular position.

[0144] The pole phase may notably refer to a relative angular position or alignment of the magnetic poles pairs relative to a specific physical reference point of the system, e.g. a sensor location. In particular, the pole phase may be indicative of a relative angular position or alignment of the poles pair being closest / nearest to the reference point, e.g. the sensor location. The pole phase may thus span to one angular period formed by one pole pair of the track, and being indicated by an angular degree exemplarily starting from 0 degree, e.g. for indicating a transition between one pole pair and the (e.g. clockwise) adjacent pole pair, passing through 180 degree e.g. for indicating a transition between the poles of the pole pair. By an opposite pole phase may be intended a pole phase being shifted by + / - 180 degree with respect to the referenced one.

[0145] In case of the first and the second number are co-prime, i.e. the greatest common divisor of the first and the second number is 1, the above described particular pole phases arrangement may be achieved by the first and the second angle being a straight angle, e.g. 180-degree angle, substantially 180° (e.g. within a tolerance margin preferably of at most ±10°). Otherwise, the above described particular pole phases arrangement may be achieved by the first and the second angle each being substantially equal to an odd multiple of a straight angle divided by the greatest common divisor of the first and the second number (e.g. a product of an odd integer number multiplied to 180° (e.g. with a tolerance margin). For example, in case the greatest common divisor being 2, each of the first and the second angle may be one of : a right angle (e.g. substantially 90°) and a sum of three right angle (e.g. substantially 90°+90°+90°). In case the greatest common divisor being 3, each of the first and the second angle may be one of : a 60° angle, a 180° angle and a 300° angle.

[0146] Examples of this embodiment are shown (inter alia) in FIG. 1, FIG. 3, FIG. 6, FIG. 19, FIG. 20.According to a ninth aspect, the present invention also provides a method of determining an angular position of a magnetic source relative to a sensor device, wherein the magnetic source is rotatable about a rotation axis and comprises at least two circular tracks (e.g. T1,T2; T1,T2,T3), including a first circular track (e.g. Tl) having a first number (e.g. Ml) of magnetic pole pairs for generating a first magnetic field having a first magnetic field pattern periodicity with respect to said rotation axis , and a second circular track (e.g. T2) and optionally also a third circular track (e.g. T3) having a second number (e.g. N2) of magnetic poles pairs for generating a second magnetic field having a second magnetic field pattern periodicity with respect to said rotation axis; wherein a greatest common divisor of the first (e.g. Ml) and second number (e.g. N2) is a positive integer number; and wherein a first quotient of the first number (e.g. Ml) divided by the greatest common divisor is an even number, and a second quotient of the second number (e.g. N2) divided by the greatest common divisor is odd number, or vice versa (meaning that the first quotient is an odd number and the second quotient is an even number); the method comprising the steps of: a) measuring by the sensor device at least one magnetic field component of the first magnetic field at two positions around the rotation axis, one angularly spaced from the other by a first angle with respect to the rotation axis; c) measuring by the sensor device at least one magnetic field component of the second magnetic field at two positions around the rotation axis, one angularly spaced from the other by a second angle with respect to the rotation axis; g) determining an angular position (e.g. 9) based on the measured magnetic field components, notably by combining said measured magnetic field components of the first magnetic field at said two positions to produce a first track signal, by combining said measured magnetic field components of the second magnetic field at said two positions to produce a second track signal, and by determining said angular position (e.g. 9) based on said first and second track signal; wherein each of said first and second angle being substantially equal to a product of an odd integer number multiplied to 180° divided by the greatest common divisor.

[0147] According to another aspect, the present invention also provides a motor assembly comprising a sensor device according to the second aspect.

[0148] According to another aspect, the present invention also provides a motor assembly comprising a processor configured for performing a method according to the third, fourth, fifth, sixth or ninth aspect.

[0149] According to another aspect, the present invention also provides a motor assembly comprising a magnetic source according to the seventh aspect.

[0150] Particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

[0151] Brief description of the drawings

[0152] FIG. 1(a) shows an illustrative example of an angular position sensor system according to an embodiment of the present invention, showing a magnetic source with two concentric circular tracks, each comprising a plurality of alternating magnetic poles, and a sensor device capable of measuring two magnetic field components at each of four different sensor locations schematically indicated by black circles. The sensor device may comprise a printed circuit board and two semiconductor devices, each comprising two magnetic sensors spaced apart by a predefined distance.

[0153] FIG. 1(b) shows an illustrative example of a semiconductor substrate that can be used in the system of FIG. 1(a). The semiconductor substrate comprises two magnetic sensor structures, each comprising an integrated magnetic flux concentrator (IMC) and two horizontal Hall elements.

[0154] FIG. 1(c) shows another illustrative example of such a semiconductor substrate comprising two magnetic sensor structures, each comprising a horizontal Hall element and a vertical Hall element.

[0155] FIG. 1(a) to FIG. 1(c) may be jointly referred to as FIG. 1.

[0156] FIG. 2A shows an illustrative example of a sensor device according to an embodiment of the present invention, which can be used in the angular position sensor system of FIG. 1(a), and shows a set of mathematical formulas for determining an absolute angular position.

[0157] FIG. 2B shows a variant of FIG. 2B, for use in combination with a magnetic source having two circular tracks as in the system of FIG. 1(a), but wherein the inner track has an even number of pole pairs, and the outer track has an odd number of pole pairs, and shows mathematical formulas for determining an absolute angular position.

[0158] FIG. 3(a) shows an illustrative example of another angular position sensor system according to another embodiment of the present invention, showing a magnetic source with three concentric circular tracks, each comprising a plurality of alternating magnetic poles, and a sensor device capable of measuring two magnetic field components at each of four different sensor locations schematically indicated by black circles. The sensor device may comprise a printed circuit board and two semiconductor devices, each comprising two magnetic sensors spaced apart by a predefined distance.

[0159] FIG. 3(b) is a replica of FIG. 1(b).

[0160] FIG. 3(c) is a replica of FIG. 1(c).

[0161] FIG. 3(a) to FIG. 3(c) may be jointly referred to as FIG. 3.

[0162] FIG. 4 shows an illustrative example of a sensor device according to an embodiment of the present invention, which can be used in the angular position sensor system of FIG. 3(a). The device of FIG. 4 can be seen as a variant of the device of FIG. 2A, wherein the third and fourth sensor position are swapped.FIG. 5 shows which magnetic field components are measured by the sensor device of FIG. 3(a) and FIG. 4, and shows mathematical formulas that can be used for determining an absolute angular position of the sensor device relative to the magnetic source. The attentive reader will recognize that these are exactly the same formulas as in FIG. 2A and FIG. 2B.

[0163] FIG. 6 shows a variant of FIG. 3(a), wherein the central track has an odd number of magnetic pole pairs, and the inner and outer track have an even number of magnetic pole pairs, as another embodiment of the present invention.

[0164] FIG. 7 shows which magnetic field components are measured by the sensor device of FIG. 6, and shows again the same mathematical formulas for determining an absolute angular position of the sensor device relative to the magnetic source.

[0165] FIG. 8 shows a graph with simulation results of a first and second sum signal for an arrangement as illustrated in FIG. 5. As can be seen, the amplitudes of the sum curves are relatively large and relatively constant, and the sum signals have a periodicity of eight, corresponding to the periodicity of the first track (sometimes also referred to herein as the "master" track).

[0166] FIG. 9 shows a graph with simulation results of the first and second difference signal for an arrangement as illustrated in FIG. 5. As can be seen, the amplitudes of the difference curves are relatively small, but relatively constant, and the difference signals have a periodicity of seven, corresponding to the periodicity of the second and third track (sometimes also referred to herein as "nonius tracks").

[0167] FIG. 10 and FIG. 11 show illustrative examples of semiconductor substrates with various sensor structures as may be used in embodiments of the present invention.

[0168] FIG. 12 shows a high-level block-diagram of a sensor device that can be used in embodiments of the present invention. This sensor device comprises two semiconductor substrates (or sensor chips), each comprising two magnetic sensor structures, and a biasing and readout-circuit, and a processing circuit. The two semiconductor substrates are communicatively interconnected, and one of the semiconductor substrates is configured for determining the absolute angular position.

[0169] FIG. 13 shows a high-level block-diagram of another sensor device that can be used in embodiments of the present invention. This sensor device also comprises two semiconductor substrates, each comprising two magnetic sensor structures, and a biasing and readout-circuit, and a processing circuit, but further comprises an external processor communicatively connected to each of the semiconductor substrates, and configured for determining the absolute angular position.

[0170] FIG. 14 shows a flowchart of a method of determining an absolute angular position proposed by the present invention.

[0171] FIG. 15 shows a flowchart of a method of determining an absolute angular position of an angular position sensor system comprising a magnetic source with two circular tracks and a sensor device having four sensor locations, e.g. as illustrated in FIG. 1, or FIG. 2A, or FIG. 2B, or FIG. 19, as an embodiment of the present invention.FIG. 16 shows a flowchart of a method of determining an absolute angular position of an angular position sensor system comprising a magnetic source with three circular tracks and a sensor device having four sensor locations, e.g. as illustrated in FIG. 3 to FIG. 5, or FIG. 20, as an embodiment of the present invention.

[0172] FIG. 17 shows a flowchart of a method of determining an absolute angular position of an angular position sensor system comprising a magnetic source with three circular tracks and a sensor device having four sensor locations, e.g. as illustrated in FIG. 6 and FIG. 7, or FIG. 20, as an embodiment of the present invention.

[0173] FIG. 18A shows an example of a magnetic source comprising three circular tracks, according to an embodiment of the present invention. FIG. 18B shows an example of an axially magnetized ring magnet. FIG. 18C shows an example of an AL or axial-lateral magnetized ring magnet.

[0174] FIG. 18A, FIG. 18B and FIG. 18C may be jointly referred to as FIG. 18.

[0175] FIG. 19 shows an illustrative example of an angular position sensor system, according to another embodiment of the present invention. The magnetic source comprises two cylindrical tracks.

[0176] FIG. 20 shows an illustrative example of an angular position sensor system, according to another embodiment of the present invention. The magnetic source comprises three cylindrical tracks.

[0177] FIG. 21 shows an example of a magnetic source comprising three cylindrical tracks, according to an embodiment of the present invention.

[0178] The drawings are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. Any reference signs in the claims shall not be construed as limiting the scope. In the different drawings, the same reference signs refer to the same or analogous elements.

[0179] Detailed description of illustrative embodiments

[0180] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

[0181] Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0182] Moreover, the terms top, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of theinvention described herein are capable of operation in other orientations than described or illustrated herein.

[0183] It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

[0184] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0185] Similarly, it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

[0186] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0187] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.In this document, unless explicitly mentioned otherwise, the term "magnetic sensor device" or "sensor device" refers to a device comprising at least one "magnetic sensor" or at least one magnetic "sensor element", preferably integrated in a semiconductor substrate. The sensor device may be comprised in a package, also called "chip", although that is not absolutely required.

[0188] In this document, the term "sensor element" or "magnetic sensor element" or "magnetic sensor" can refer to a component or a group of components or a sub-circuit or a structure capable of measuring a magnetic quantity, such as for example a magneto-resistive (MR) element, a GMR element, an XMR element, a horizontal Hall plate, a vertical Hall plate, a Wheatstone-bridge containing at least one (but preferably four) magneto-resistive elements, etc. or combinations hereof.

[0189] In embodiments of the present invention, the term "magnetic sensor" or "magnetic sensor structure" may refer to an arrangement comprising one or more integrated magnetic concentrators (IMC), also known as integrated flux concentrators, and one or more horizontal Hall elements arranged near the periphery of the IMC, for example a disk shaped IMC with four horizontal Hall elements angularly spaced by multiples of 90°.

[0190] In this document, the expression "ID magnetic pixel" typically refers to a magnetic sensor element capable of measuring only one magnetic field component.

[0191] In this document, the expression "2D magnetic pixel" typically refers to a magnetic sensor structure capable of measuring only two orthogonal magnetic field components.

[0192] In this document, the expression "3D magnetic pixel" typically refers to a magnetic sensor structure capable of measuring three orthogonal magnetic field components.

[0193] In this document, the expression "in-plane component of a magnetic field vector" and "projection of the magnetic field vector in the sensor plane" mean the same. If the sensor device is or comprises a semiconductor substrate, this also means "magnetic field components parallel to the semiconductor plane". In this document, in-plane components are typically labelled Bx or By.

[0194] In this document, the expression "out-of-plane component of a vector" and "Z component of the vector" and "projection of the vector on an axis perpendicular to the sensor plane" mean the same. In this document, out-of-plane components are typically labelled Bz.

[0195] Embodiments of the present invention are typically described using an orthogonal coordinate system which is fixed to the sensor device or to a substrate comprising a group of sensors, and having three axes X, Y, Z, where the X and Y axis are parallel to the substrate, and the Z-axis is perpendicular to the substrate.

[0196] In this document, horizontal Hall plates are typically referred to by Hl, H2, etc., and signals obtained from horizontal Hall plates are typically referred to as hl, h2, etc.

[0197] In this document, vertical Hall plates are typically referred to by VI, V2, etc., and signals obtained from vertical Hall plates are typically referred to as vl, v2, etc.

[0198] In this document, IMC means "integrated magnetic concentrator".1

[0199] In this document, ADC means "analog to digital convertor".

[0200] In this document, DSP means "digital signal processor" or "digital processing circuit". This may comprise a programmable processor.

[0201] In this document "NV-memory" means "non-volatile memory", e.g. flash memory.

[0202] In this document, the expressions "magnetic source" and "magnet" mean the same.

[0203] The term "track" as part of a magnetic source, as used herein, typically refers to a ring-shaped or annular shaped or cylindrical shaped object. These tracks have a "width" extending in the radial or an axial direction, respectively.

[0204] The expression "the sensor is located above the track" means that the sensor is located at a predefined distance measured in a direction perpendicular to the track. In case of planar tracks (e.g. as in FIG. 1) this means at a distance in the axial direction of the magnet. In case of cylindrical tracks (e.g. as in FIG. 19) this means at a distance in the radial direction of the magnet.

[0205] The term "centreline of a track" as used herein refers to a virtual circle, situated at the surface of the track, in the middle of the width, e.g. as illustrated in FIG. 1(a) or FIG. 19. The sensor positions may be located "above" these centrelines, but that is not absolutely required.

[0206] The expression "the sensors or sensor structures are spaced apart by a distance ds" as used herein means that centres (or a reference point) of the sensors or sensor structures are spaced apart by the distance "ds", for example as illustrated in FIG. 1(b) or FIG. 1(c).

[0207] The expression "a vertical Hall element oriented in the X-direction" is a shortcut for saying "a vertical Hall element with an axis of maximum sensitivity oriented in the X-direction".

[0208] In this document, the expression "the sensor is located on the first track" and "the sensor is located above the first track" mean the same. In practice, there is always a certain distance (called "air gap") between the sensor and the track, in order to avoid mechanical wear.

[0209] The abbreviation PCB stands for Printed Circuit Board.

[0210] The abbreviation IC stands for "integrated circuit". In the context of the present invention, an integrated circuit can mean a "semiconductor substrate" (e.g. a CMOS substrate), optionally mounted on a lead frame and / or optionally at least partially surrounded by a moulding compound to form a so called "chip".

[0211] The present invention relates to angular position sensor systems, angular position sensor devices, methods of determining an angular position, and to a magnetic source for use in such an angular position sensor system. More specifically, the present invention provides an absolute angular position sensor system where the accuracy of the angular position determined by the sensor device has a reduced sensitivity to the mounting position of the sensor device relative to the magnetic source, or stated in other words, where the mounting requirements for achieving a certain accuracy are relaxed.In order to achieve this, the inventors came to the idea of providing an angular position sensor system comprising a magnetic source rotatable about a rotation axis, and a sensor device mounted in the vicinity of the magnetic source.

[0212] The magnetic source comprises at least two (e.g. two or three) circular tracks including a first circular track T1 having a first number Ml of magnetic pole pairs, and a second circular track T2 having a second number N2 of magnetic pole pairs. If present, the third track T3 preferably also has N2 magnetic pole pairs. Thus 2x Ml alternating magnetic poles of the first track and 2x N2 alternating magnetic poles of the second track are facing the sensor device.

[0213] Importantly, the first number Ml and the second number N2 are coprime numbers, i.e. that the greatest common divisor of Ml and N2 is 1 (one). In preferred embodiments, one of the first and second number is an even number, and the other is an odd number, e.g. Ml is even and N2 is odd, or Ml is odd and N2 is even, but that is not absolutely required, and it is also possible that both Ml and N2 are odd (e.g. Ml=5 and N2=3, or vice versa).

[0214] The sensor device comprises four magnetic sensors including a first, second, third and fourth magnetic sensor (SI, S2, S3, S4) situated at four different sensor locations (Pl, P2, P3, P4 respectively) above said at least two circular tracks. Each magnetic sensor is configured for measuring at least two magnetic field components, preferably two orthogonal magnetic field components, e.g. in case of planar tracks (as in FIG. 1) one magnetic field component oriented in a circumferential direction, and another magnetic field component oriented in an axial direction of the magnetic source, or e.g. in case of cylindrical tracks (as in FIG. 19) one magnetic field component oriented in the radial direction, and another magnetic field component oriented in the circumferential direction; as can be achieved e.g. using so called 2D magnetic pixels or 3D magnetic pixels, e.g. as illustrated in FIG. 1(b) or FIG. 1(c).

[0215] The first and the second sensor (SI and S2) are preferably implemented on a first semiconductor substrate, and are preferably spaced apart by a predefined distance "dl2", e.g. substantially equal to a predefined value "ds". The third and the fourth sensor (P3 and P4) are preferably implemented on a second semiconductor substrate, and are preferably spaced apart by a predefined distance "d34", e.g. also substantially equal to a predefined value "ds" in a predefined direction X, which may be radially oriented with respect to the magnet (e.g. as in FIG. 1 or FIG. 3 or FIG. 6), or may be axially oriented (e.g. as in FIG. 19 or FIG. 20).

[0216] In case the magnetic source has planar tracks, the first and the third sensor (SI, S3) are preferably angularly spaced by an angle of about 180°, (e.g. within a tolerance margin of ±10°, or ±7°, or ±5°, or ±4°, or ±3°, or ±2°, or ±1°) with respect to the rotation axis, and the second and the fourth sensor (S2, S4) are preferably angularly spaced by an angle of about 180° (e.g. with a similar tolerance margin). Optionally, the four sensor locations (Pl, P2, P3, P4) are located on a virtual line, which preferably passes through the centre of the circular tracks, but that is not absolutely required, and it suffices that this virtual line is located at a small distance from said centre (e.g. at a distance of at most 5.0 mm, or at adistance smaller than 10% of the outer radius of the magnetic source). The first and the second sensor location (Pl, P2) are located on a first side of said centre, and the third and the fourth sensor location (P3, P4) are located on an opposite side of the centre.

[0217] In case the magnetic source has cylindrical tracks, the first and the second sensor SI, S2 may be located on a first line segment parallel to the rotation axis, and the third and fourth sensor S3, S4 may be located on a second line segment parallel to the rotation axis, e.g. as illustrated in FIG. 19 or FIG. 20.

[0218] One of the first and second sensor location is located above the first track Tl, and the other of the first and second sensor location is not located above the first track, but e.g. above the second track T2 or above the third track T3, if present. One of the third and fourth sensor location is located above the first track Tl, and the other of the third and fourth sensor location is not located above the first track, but e.g. above the second track T2 or above the third track T3, if present. Thus two of said four sensor locations are located above the first track Tl.

[0219] The angular position sensor system further comprises a processing circuit configured for determining an absolute angular position (0) based on the measured magnetic field components.

[0220] In an embodiment, the processing circuit is configured for determining a first and a second linear combination of the two parallel magnetic field components measured by the first and the third magnetic sensor (SI, S3), and for determining a third and a fourth linear combination of the two parallel magnetic field components measured by the second and the fourth magnetic sensor (S2, S4), and for determining said angular position (0) based on the first, second, third and fourth linear combination.

[0221] In an embodiment, the processing circuit is configured for determining a first sum (suml) and a second sum (sum2) of two parallel magnetic field components measured by the first and the third magnetic sensor (SI, S3), and for determining a first difference (diffl) and a second difference (diff2) of two parallel magnetic field components measured by the second and the fourth magnetic sensor (S2, S4), and for determining said angular position (0) based on the first and second sum (suml, sum2) and based on the first and second difference (diffl, diff2).

[0222] These are the main underlying principles of the present invention.

[0223] Referring now to the figures.

[0224] FIG. 1(a) shows an illustrative example of an angular position sensor system 100, and shows a magnetic source 110 with two concentric circular tracks Tl, T2, each comprising a plurality of alternating magnetic poles (thereafter also referred as magnetic pole pairs, wherein each pole pair consists of two poles with alternated magnetic polarisation, i.e. one pole of the pair having an opposed or inversed polarisation with respect to the other pole of the pair), and a sensor device 120 capable of measuring two orthogonal magnetic field components By, Bz at four different sensor locations Pl, P2, P3, P4 schematically indicated by black circles.The magnetic source 110 may have an inner diameter in the range from 25 to 50 mm, but of course, the present invention is not limited hereto. In the example of FIG. 1(a), the first track T1 has 8 (eight) magnetic pole pairs, thus the sensor at position Pl will see 16 (sixteen) alternating magnetic poles when the magnet 110 makes a full 360° rotation, and the second track T2 has 7 (seven) magnetic pole pairs, thus the sensor at position P2 will see 14 (fourteen) alternating magnetic poles when the magnet 110 makes a full 360° rotation. Even if the first track T1 (having less magnetic pole pairs than the second track T2) is illustrated in this embodiment as being outside the track T2, this feature is not required for the invention to work, as the track T1 can alternatively be arranged inside the second track T2.

[0225] The sensor device 120 may comprise a printed circuit board (PCB) and two (e.g. only two) semiconductor devices 121, 122 (e.g. two semiconductor substrates or two packaged semiconductor devices, also known as "chips"), each comprising two magnetic sensors (e.g. two 2D magnetic pixels or two 3D magnetic pixels) spaced apart by a predefined distance "ds", e.g. in the range from 1.0 to 3.0 mm, or in the range from 1.5 to 2.5 mm. The first semiconductor device 121 has a first magnetic sensor SI located at a first sensor position Pl situated above the first track T1 (also referred to as "outer track" in this system 100), and has a second magnetic sensor S2 located at a second sensor location P2 situated above the second track T2 (also referred to as "inner track" in this system 100).

[0226] The sensor locations Pl and P3 are preferably situated above the centreline Cl of the first track Tl, i.e. substantially halfway between the inner radius R2 and the outer radius R3 of the first track Tl.

[0227] The sensor locations P2 and P4 are preferably situated above the centreline C2 of the second track T2, i.e. substantially halfway between the inner radius R1 and the outer radius R2 of the second track T2, but the exact positions are not critical for the invention to work.

[0228] In the example shown in FIG. 1(a) the inner track Tl and the outer track T2 are abutting each other, which offers the advantage that the total width (R3-R1) can be reduced, and / or the arrangement can be more compact, without considerably decreasing the accuracy.

[0229] In a variant (not shown) of FIG. 1(a) the two tracks are separated from each other by a small air gap, or by a small groove, or by a small non-magnetic region, but if present, the width of this air gap or groove or non-magnetic region is preferably smaller than 1.0 mm, or smaller than 0.5 mm, or smaller than 0.2 mm.

[0230] FIG. 1(b) shows an illustrative example of such a semiconductor device 121, (the same device can also be used as semiconductor device 122), comprising two magnetic sensors SI, S2, each comprising an integrated magnetic concentrator (IMC) disk and two horizontal Hall elements, arranged for measuring a magnetic field component Bz in the axial direction of the magnetic rings (corresponding to the local Z-direction of the semiconductor substrate), and a magnetic field component By in the circumferential direction of the magnetic rings (corresponding to the local Y-direction of the semiconductor substrate), at two sensor locations Pl and P2. Of course, the semiconductor devices 121,122 may comprise further circuitry, e.g. one or more of: a biasing and readout-circuit, a processing circuit, a communication interface, etc. e.g. as will be described further in FIG. 12 and FIG. 13. The two devices 121, 122 may be identical, or may have identical hardware but different firmware, but that is not absolutely required. In the block-diagram of FIG. 12, the two devices 1221, 1222 are communicatively connected to each other, and one of them may be configured for calculating and providing the absolute angular position. In the block-diagram of FIG. 13 the absolute angular position is calculated by a processor 1335 outside of the sensor devices 1321, 1322. This processor is communicatively connected to each of the sensor devices, and may also be located on the PCB, but that is not absolutely required.

[0231] In a variant (not shown) of FIG. 1(b) each magnetic sensor SI, S2 has an IMC and four horizontal Hall elements, angularly spaced by multiples of 90°. Such a magnetic sensor structure is capable of measuring three orthogonal magnetic field components, and is referred to as a "3D magnetic pixel".

[0232] FIG. 1(c) shows another illustrative example of a semiconductor device 121, (the same device can also be used as semiconductor device 122) comprising two magnetic sensors SI, S2, each comprising a horizontal Hall element and a vertical Hall element, arranged for measuring said axial Bz and circumferential By magnetic field component at two sensor locations Pl, P2.

[0233] In a variant (not shown) of FIG. 1(c), each of the magnetic sensors has a horizontal Hall element, and two vertical Hall elements located on opposite sides of the horizontal Hall element, oriented with their axis of maximum sensitivity in the Y-direction.

[0234] In a further variant (not shown), each of the magnetic sensors comprises one horizontal Hall element and four vertical Hall elements, arranged near the four sides of the horizontal Hall elements, including two vertical Hall elements oriented in the X-direction, and two vertical Hall elements oriented in the Y-direction. Such a magnetic sensor structure is capable of measuring three orthogonal magnetic field components, and is referred to as a "3D magnetic pixel".

[0235] In the illustrative example of FIG. 1(a) the outer track T1 has eight magnetic pole pairs (Ml=8), and the inner track T2 has seven magnetic pole pairs (N2=7). In a variant of FIG. 1, Ml=7, and N2=8, but of course other numbers of Ml and N2 can also be used, for example Ml=3 and N2=5 (or vice versa), or Ml=4 and N2=7 (or vice versa), or Ml=13 and N2=14 (or vice versa).

[0236] The number Ml is preferably a value in the range from 5 to 32. The number N2 may be equal to (Ml+1), or may be equal to (Ml-1), or may be equal to (Ml+2), or may be equal to (Ml-2), or may be equal to (Ml+3), or may be equal to (Ml-3). Preferably the greatest common divisor (GCD) of Ml and N2 is "1".

[0237] In the illustrative example of FIG. 1(a) the first track T1 has a first width wl in the radial direction, and the second trackT2 has a second width w2 in the radial direction. In the particular example of FIG. 1(a) wl is equal to w2 within a tolerance margin of ±10%, butthat is not required forthe inventionto work. In a variant, the outer track T1 has a width wl larger than w2, e.g. at least 25% larger (i.e. wl / w2 > 1.25), or at least 50% larger (i.e. wl / w2 > 1.50), or at least 75% larger (i.e. wl / w2 > 1.75), or at least twice as large (i.e. wl / w2 > 2.0). In another variant, the outer track T1 has a width wl smaller than w2, e.g. at least 25% smaller (i.e. w2 / wl > 1.25), or at least 50% smaller (i.e. w2 / wl > 1.50), or at least 75% smaller (i.e. w2 / wl > 1.75), or at least twice as small (i.e. w2 / wl > 2.0).

[0238] In the illustrative example of FIG. 1(a), the sensor device 120 comprises a printed circuit board 120 with a rectangular shape, but of course, the present invention is not limited thereto, and other suitable shapes of the PCB can also be used.

[0239] FIG. 2A shows an illustrative example of a sensor device 220a that can be used in the angular position sensor system 100 of FIG. 1(a). As can be seen, this sensor device comprises a C-shaped printed circuit board 220a comprising two packaged devices or sensor chips 221, 222, spaced apart from each other along a predefined direction X. As can be seen, the PCB 220a has a through-opening, or a cut-out substantially halfway between the two sensor devices 221, 222. The first sensor chip 221 comprises a first magnetic sensor SI capable of measuring two orthogonal magnetic field components Byl, Bzl oriented in a second direction Y and a third direction Z, perpendicular to the direction X, at a first sensor location Pl (schematically indicated by a black dot), and a second magnetic sensor S2 capable of measuring By2, Bz2 at a second sensor location P2. The second sensor chip 222 comprises a third magnetic sensor S3 capable of measuring two magnetic field components By3, Bz3 and a fourth magnetic sensor S4 capable of measuring two magnetic field components By4, Bz4.

[0240] While not explicitly shown in FIG. 2A (but see e.g. FIG. 12 or FIG. 13), the sensor device 220a also comprises a processing circuit 1252a or a processor 1355 for determining an absolute angular position of the magnetic source 110 of FIG. 1(a). The processing circuit may be incorporated inside one of the sensor devices 221, 222, or may be incorporated in both sensor devices 221, 222 (e.g. for redundancy purposes), and / or may be provided as an external processor outside of the sensor devices 221, 222.

[0241] The sensor device 120 is capable of determining an absolute position of the magnetic source, e.g. in a manner similar as described in EP42351O8(A1), e.g. using a plurality of coefficients that may be determined during a calibration procedure. In fact, based on the signals measured by each of the semiconductor substrates 221, 222 two angular position values can be determined, and by combining them, e.g. averaging them, a more accurate value for the absolute angular position is obtained.

[0242] In a preferred embodiment, however, the processing circuit is configured for calculating a first sum "suml" and a second sum "sum2" of the signals obtained from the first sensor SI and the third sensor S3 (which in the example of FIG. 1(a) are to be located above the first track T1 having an even number of magnetic pole pairs), and for calculating a first difference "diffl" and a second difference " diff2 of the signals obtained from the second sensor S2 and the fourth sensor S4 (which in the exampleof FIG. 1(a) are located above the second track T2 having an odd number of magnetic pole pairs), for example in accordance with the following formulas:

[0243] suml = Bzl+Bz3 [1]

[0244] sum2 = Byl+By3 [2]

[0245] diffl = Bz2-Bz4 [3]

[0246] diff2 = By2-By4 [4]

[0247] FIG. 8 and FIG. 9 shows an illustrative example how these sum and difference signals may look like.

[0248] The inventors surprisingly discovered that, by calculating the sums of corresponding magnetic field components measured by the sensors that are located above the first track T1 having an even number of magnetic pole pairs, a first set of signals (suml, sum2) is obtained having the same periodicity as the first track T1 (in the example of FIG. 1(a) and FIG. 8 this periodicity is 8 (eight), and the period is 36078=45°), and which have an amplitude that is substantially constant over the full 360° rotation, which means in fact, that the influence of the magnetic field generated by the second track T2 is largely or even completely removed. It is important to realize that these sum signals may be obtained without requiring a set of coefficients that need to be determined during a calibration procedure, which is a huge advantage that should not be underestimated.

[0249] Likewise, the inventors discovered that, by calculating the differences of corresponding magnetic field components measured by the sensors that are located above the second track T2 having an odd number of magnetic pole pairs, a second set of signals (diffl, diff2) is obtained having the same periodicity as the second track T2 (in the example of FIG. 1(a) and FIG. 9 this periodicity is 7 (seven), and the period is 360° / 7 « 51,4°), and which have an amplitude that is substantially constant over the full 360° rotation, which means (again) that the influence of the magnetic field generated by the other track is largely or even completely removed.

[0250] In other words, the cross-talk between the two adjacent tracks is largely or completely removed by selecting one track with an even number of pole pairs and another track with an odd number of pole pairs, and by arranging the four sensors as described above, (e.g. at approximately diametrically opposite locations), and by measuring two orthogonal magnetic field components on said four sensor locations, and by calculating the pairwise sums and differences, without requiring a set of coefficients that need to be determined during a calibration procedure. This is true even if the two tracks are abutting each other, thus allowing miniaturisation of the angular position sensor system. The absolute angular position can then be derived from the two sums and the two differences, or written in mathematical terms:

[0251] 9=fl(suml,sum2, diffl, diff2) [5]

[0252] where f is a predefined function or technique.

[0253] For example, the absolute position can be determined as follows: by determining a first angle 0M based on the sum signals, e.g. in accordance with the formula:

[0254] 9M=f2(suml,sum2) [6]where f2 is a predefined function or technique; and by determining a second angle 9N based on the difference signals, e.g. in accordance with the formula:

[0255] 0N=f3(diffl,diff2) [7]

[0256] where f3 is a predefined function or technique; and by determining an absolute angle 0 based on 0M and ON, e.g. in accordance with the formula:

[0257] 0=f4(0M, ON) [8]

[0258] where f4 is a predefined function or technique, e.g. using the nonius-principle.

[0259] In a particular embodiment, the sum signals suml, sum2 are converted into a first set of quadrature signals sumlq, sum2q, e.g. by amplitude and / or phase matching e.g. using the Lissajous approach, and the first angle 0M is determined using an actangent function, e.g. in accordance with the formula:

[0260] 0M=atan2(sumlq,sum2q) [9]

[0261] where atan2 is the two-argument arctangent function. Likewise, the difference signals diffl, diff2 are converted into a second set of quadrature signals difflq, diff2q, and the second angle ON is determined using an actangent function, e.g. in accordance with the formula:

[0262] 0N=atan2(difflq,diff2q)

[0010]

[0263] It is noted that the amplitudes of the sum signals (e.g. about 40 mT in FIG. 8) may be much higher than the amplitudes of the difference signals (e.g. about 7 mT in FIG. 9), but an accurate value of the absolute angle 0 can still be obtained, e.g. by determining the angle 0 in accordance with the formula:

[0264] 0= 0M+(kl*360° / Ml)

[0011]

[0265] where kl is the segment number of the first track T1 for which the measured values of ON and 0M show a best match. The value of kl may be determined using a Vernier (or Nonius) approach, e.g. using the unique relationship between the values of the two angles 0M, ON (for example relying on a difference calculation between the two angles). The value of kl can also be determined for example as follows: by finding two integer values kl, k2 for which the expression 0M+(kl*360° / Ml) is closest to the expression 0N+(k2*360° / N2).

[0266] Interestingly, the hardware of a particular sensor device 220 can be used in combination with a relatively large number of magnetic sources 110 having substantially the same dimensions (e.g. same inner and outer radius of the tracks), but having different numbers of magnetic pole pairs. For example in the example of FIG. 1(a) Ml=8 and N2=7, but the same sensor device 120, loaded with other firmware, can also be used in combination with a magnet having an outer track T1 with Ml=10 and an inner track T2 with N2=9, or with a magnet having an outer track T1 with Ml=10 and an inner track T2 with N2=7, etc.FIG. 2B illustrates that a sensor device 220b having the same hardware as the sensor device 220a of FIG. 2A can even be used in combination with a magnetic source having an inner track with an even number of magnetic pole pairs, and an outer track having an odd number of magnetic pole pairs. The track with the even number of magnetic pole pairs can still be referred to as the "first track" with Ml magnetic pole pairs, and the track with the odd number of magnetic pole pairs can still be referred to as the "second track" with N2 magnetic pole pairs, and SI and S3 are still located above the first track Tl, and S2 and S4 are still located above the second track T2. FIG. 2B shows that the same formulas as illustrated in FIG. 2A are applicable. As mentioned above, the sensor device 220a and the sensor device 220b may have the same hardware but different firmware.

[0267] It is noted that an absolute angle value can also be determined if Ml is an odd number, and N2 is also an odd number, but the value may be less accurate, e.g. due to cross-talk.

[0268] FIG. 3(a) shows an illustrative example of another angular position sensor system 300, which can be seen as a variant of the angular position sensor system 100 of FIG. 1 and FIG. 2. The main differences between the system 300 of FIG. 3(a) and the system 100 of FIG. 1(a) are the following: i) the magnetic source 310 has three concentric circular tracks, namely, a first track Tl (also referred to as central track), a second track T2 (also referred to as inner track) and a third track T3 (also referred to as outer track). Importantly: the third track T3 has the same number N3 of magnetic pole pairs as the second track T2 (thus N3=N2), and the magnetic pole pairs of the second track T2 and the third track T3 are radially aligned;

[0269] ii) the fourth sensor location P4 is located on the third track T3 instead of the second track T2. Thus, in this embodiment, the sensor devices 321 and 322 are arranged asymmetrically with respect to the centre of the magnetic source 310, but this may offer the advantage that the angular position sensor system is more robust against mounting position offset and / or against a shifting of the rotating axis along a virtual line on which the sensors lie, because a decrease of the signals of SI may be compensated by an increase of the signals of S3 (for example), such that a combination of the signals of SI and S3 may remain substantially unchanged. Likewise, a combination of the signals of S2 and S4 may remain substantially unchanged.

[0270] Everything else mentioned above is also applicable here, for example:

[0271] - the four sensor locations Pl to P4 of FIG. 3(a) may be located on a virtual line, which passes through the centre of the magnet or which is located at a short distance from the centre (e.g. at a distance of at most 10% of the outer radius of the magnetic source, or at most 5%, or at most 3%, or at most 2%, or at most 1%), but as described above, that is not absolutely required;

[0272] - the four sensors SI to S4 are preferably configured for each measuring two orthogonal magnetic field components, one in the axial direction and one in the circumferential direction of the magnetic source;- the three tracks Tl, T2, T3 preferably abut each other, meaning that no air gap or groove or non-magnetic zone is required to separate the tracks, although it may. If present, such air gap or groove or non-magnetic zone is preferably smaller than 1.0 mm, or smaller than 0.5 mm, or smaller than 0.2 mm.

[0273] In preferred embodiments, the track width wl of the first track Tl (measured in the radial direction) is preferably larger than the track width w2 of the second track T2, preferably at least 25% or at least 50% or at least 75% larger, or written mathematically: wl>w2, e.g. (wl / w2) > 1.25, or (wl / w2) > 1.50, or (wl / w2) > 1.75. The track width wl of the first track Tl is preferably also larger than the track width w3 of the third track T3, e.g. at least 25% larger, or at least 50% larger, or at least 75% larger. The track width w2 of the second track T2 may be substantially equal to the track width w3 of the third track T3 (e.g. within a tolerance margin of ±25%, or ±20%, or ±15%, or ±10%, or ±5%), but that is not absolutely required.

[0274] FIG. 3(b) and FIG. 3(c) are identical to FIG. 1(b) and FIG. 1(c), showing that the same 2D magnetic pixels described above can also be used in the angular position sensor system 300 of FIG. 3. The variants hereof, having more horizontal Hall elements or more vertical Hall elements, e.g. the 3D magnetic pixels described above, can also be used in the angular position sensor system of FIG. 3(a).

[0275] FIG. 4 shows an illustrative example of a sensor device 420 that can be used in the angular position sensor system 300 of FIG. 3(a). The sensor device 420 of FIG. 4 can be seen as a variant of the device 220a of FIG. 2A wherein the positions of S3 and S4 are swapped; and / or can also be seen as a variant of the device 220b of FIG. 2B where the position of SI and S2 are swapped. The hardware of the sensor devices 220a of FIG. 2A, 220b of FIG. 2B and 420 of FIG. 4 may be exactly the same, but the firmware may be different.

[0276] FIG. 5 shows which magnetic field components are measured by the magnetic sensors SI to S4 of the sensor devices 320 of FIG. 3(a) and 420 of FIG. 4, and shows mathematical formulas that may be used for determining an absolute angular position 9 of the sensor device 320 relative to the magnetic source 310. The attentive reader will recognize that these formulas are exactly the same formulas as in FIG. 2A and FIG. 2B.

[0277] FIG. 6 shows an angular position sensor system 600 which can be seen as a variant of the angular position sensor system 300 of FIG. 3(a). The main difference being that, the central track Tl of the magnetic source 610 has an odd number Ml of magnetic pole pairs, and each of the inner track T2 and outer track T3 has an even number N2 of magnetic pole pairs. In the specific example shown, Ml=7 and N2=8, but the present invention is not limited hereto, and magnetic sources with other numbers ofmagnetic pole pairs can also be used. Everything else mentioned above is also applicable here, for example, the magnetic poles of the second and third track T2, T3 are radially aligned; the width wl of the first track may be larger than the widths w2 and w3 of the second and third track, the widths w2 and w3 may be substantially equal (e.g. within a tolerance margin of ±25%, or ±20%, or ±15%, or ±10%, or ±5%), etc.

[0278] The angular position sensor system 600 further comprises a sensor device 620 comprising four sensors SI to S4 located on four different sensor positions Pl to P4, which may be located on a virtual line, which passes through the centre of the magnet or which is located at a short distance from the centre (e.g. at a distance of at most 10% of the outer radius of the magnetic source, or at most 5%, or at most 3%, or at most 2%, or at most 1%). Pl and P2 are located on one side of the centre of the magnetic source, P3 and P4 on the other side of the centre. As can be seen, P2 and P4 are situated above the central track Tl, Pl is located above the inner track T2, and P3 is located above the outer track T3. Thus the semiconductor substrates or sensor chips 621, 622 are located asymmetrically with respect to the centre of the magnetic source 610. As described above, this offers the advantage of having a reduced sensitivity of position offset, especially in the radial direction.

[0279] FIG. 7 is a variant of FIG. 5, and shows which magnetic field components are measured by the magnetic sensors SI to S4 of the sensor device 620 of FIG. 6, and shows mathematical formulas that can be used for determining an absolute angular position 9 of the sensor device 620 relative to the magnetic source 610. The attentive reader will recognize that these formulas are (again) exactly the same formulas as shown in FIG. 2A and FIG. 2B and FIG. 5, and that the magnetic field components obtained from SI and S3, which are located above tracks with an even number of magnetic pole pairs are summed, and that the magnetic field components obtained from S2 and S4, which are located above a track with an odd number of magnetic pole pairs, are subtracted.

[0280] Everything else described above is also applicable here, mutatis mutandis, for example, the sensor device 620 may also comprise a C-shaped printed circuit board similar to that shown in FIG. 4, and again the same hardware devices as described above (e.g. in FIG. 2A, FIG. 2B, and FIG. 5) can also be used in the system of FIG. 6 and FIG. 7, but the firmware may be different.

[0281] FIG. 8 shows a graph with simulation results of the first and second sum signal suml, sum2 for an arrangement as illustrated in FIG. 3(a) to FIG. 5 with a magnetic source 310 having a first track width wl=3.0 mm and a second and third track width w2=w3=1.0 mm. As can be seen, the amplitudes of both sum curves are relatively large (e.g. in the order of about 40 to 50 ml) and the amplitudes are substantially constant. As can be seen, the signals have a periodicity of eight, corresponding to the periodicity of 360° / 8=45° of the first track Tl of FIG. 3(a). Importantly, the sum signals suml, sum2 do not show a significant influence (cross-talk) from neighbouring track(s) having only seven magnetic polepairs. Similar simulations can of course also be performed for other magnetic sources, e.g. having only two circular tracks, and / or having other dimensions, and / or having other periodicities, and the amplitudes of the sum signals will likely change, but also in this case, the sum signals measured above tracks having an even number of magnetic pole pairs will not experience a significant influence from the magnetic field caused by neighbouring track(s) having an odd number of magnetic pole pairs.

[0282] FIG. 9 shows a graph with simulation results of the first and second difference signal diffl, diff2, for the arrangement illustrated in FIG. 3(a) to FIG. 5. As can be seen, the amplitudes of both difference curves are relatively small (e.g. in the order of about 7 mT) and the amplitudes are substantially constant over a full 360° rotation of the magnetic source. As can be seen, the difference signals have a periodicity of seven, corresponding to the periodicity of 360° / 7 « 51.4° of the second and third track T2, T3 of the magnetic source 310 of FIG. 3(a). Importantly, the difference signals diffl, diff2 do not show a significant influence (cross-talk) from neighbouring track(s) having eight magnetic pole pairs. Similar simulations can of course be performed for other magnetic sources, e.g. having only two circular tracks, and / or having other dimensions, and / or having other periodicities, but also in this case, the difference signals measured above tracks having an odd number of magnetic pole pairs will not experience a significant influence from the magnetic field caused by neighbouring track(s) having an even number of magnetic pole pairs.

[0283] FIG. 10 shows a semiconductor substrate 1021 that can be used (twice) in embodiments of the present invention, e.g. in the system 100 of FIG. 1(a) to FIG. 2B, in the system 300 of FIG. 3(a) to FIG. 5, in the system 600 of FIG. 6 and FIG. 7, but also in the systems of FIG. 19 and FIG. 20. The semiconductor substrate 1021 comprises two magnetic sensor structures, each comprising an integrated magnetic concentrator disk (IMC) spaced apart by a predefined distance dl2 in a first direction X, and each comprising two horizontal Hall elements H1,H2; H3,H4 arranged near a periphery of the IMC, angularly spaced apart by 180°. The first magnetic sensor structure allows to measure a magnetic field component Byl oriented in the Y-direction by subtracting the signals hl, h2 obtained from the two Hall elements Hl, H2, and allows to measure a magnetic field component Bzl oriented in the Z-direction by adding the signals hl, h2 obtained from the Hall elements Hl, H2. An IMC with 2 horizontal Hall elements spaced apart by 180° is a 2D magnetic pixel. Likewise, the second magnetic pixel can measure By2 at the second sensor location P2 by subtracting the signals h3, h4 obtained from the horizontal Hall elements H3, H4, and can measure Bz2 at the second sensor location P2 by adding the signals h3, h4.

[0284] In a variant (not shown), the semiconductor substrate 1021 comprises two 3D magnetic pixels, each comprising an IMC and four horizontal Hall elements angularly spaced apart by multiples of 90°, two of which are located on the X-axis.It is noted that the magnetic field component Bz2 is written to be equal to (h3+h4) without a scaling factor, because the signals obtained from the magnetic sensors need to be scaled anyway, and abstraction is made of the scaling factor. Abstraction of the scaling factor(s) is used throughout this application.

[0285] FIG. 11 shows another semiconductor substrate 1121 that can be used (twice) in embodiments of the present invention, e.g. in the system 100 of FIG. 1(a) to FIG. 2B, in the system 300 of FIG. 3(a) to FIG. 5, in the system 600 of FIG. 6 and FIG. 7, but also in the systems of FIG. 19 and FIG. 20. The semiconductor substrate 1121 comprises two magnetic sensor structures, each comprising a horizontal Hall element Hl, H2 and at least one vertical Hall element VI, V2 having an axis of maximum sensitivity oriented in the Y-direction. The vertical Hall element VI allows to measure a magnetic field component Byl oriented in the Y-direction, and the horizontal Hall element Hl allows to measure a magnetic field component Bzl oriented in the Z-direction.

[0286] In a variant (not shown), each sensor structure comprises two vertical Hall elements, located on opposite sides of the horizontal Hall element, both vertical Hall elements oriented in the Y-direction. The signals of these two vertical Hall elements may be added or averaged.

[0287] In another or a further variant (not shown), the semiconductor substrate 1121 comprises two 3D magnetic pixels, each comprising a horizontal Hall element and at least two vertical Hall elements, one oriented in the X-direction and another oriented in the Y-direction, or each comprising a horizontal Hall element and four vertical Hall elements, two being oriented in the X-direction, and the other two being oriented in the Y-direction. The signals of the vertical Hall elements oriented in the same direction may be added or averaged.

[0288] FIG. 12 shows a schematic block diagram of a sensor device 1220, as may be used in angular position sensor systems proposed by the present invention, e.g. in the angular position sensor system 100 of FIG. 1(a) to FIG. 2B, and / or in the angular position sensor system 300 of FIG. 3(a) to FIG. 5, and / or in the angular position sensor system 600 of FIG. 6 and FIG. 7.

[0289] The sensor device 1220 comprises a carrier, e.g. a printed circuit board (e.g. having an overall rectangular shape or a C-shape), and two semiconductor substrates or two sensor chips 1221, 1222. Each semiconductor substrate or sensor chip comprises:

[0290] - two magnetic sensor structures, e.g. two 2D-magnetic pixels, configured for measuring two orthogonal magnetic field components By, Bz at two different locations spaced apart in an X-direction, e.g. the sensor structures of FIG. 10 or FIG. 11, or variants thereof. Each magnetic sensor SI to S4 may be configured to provide a plurality of sensor signals originating from a plurality of magnetic sensor elements (e.g. from one or more Hall elements);- a biasing and readout circuit 1251a, 1251b for biasing the magnetic sensors. Biasing and readout circuits are known in the art, and hence need not be described in full detail here. It suffices to say that they may comprise for example one or more current sources and / or voltage sources, one or more amplifiers, one or more multiplexers, etc.

[0291] - a processing circuit 1252a, 1252b comprising at least one analog-to-digital convertor (ADC). The processing circuit may be configured for combining (in the analog or digital domain) signals obtained from the magnetic sensor elements to form magnetic field components, e.g. using the formulas of FIG. 10;

[0292] - a communication interface 1253a, 1253b configured for transmitting and / or receiving digital data to / from the other semiconductor substrate or sensor chip, e.g. via a serial bus, e.g. via an SPI-bus or another suitable communication bus;

[0293] At least one of the semiconductor substrate or sensor chip 1221, 1222 further comprises: - an output circuit 1254a for providing said absolute angular position 9.

[0294] In the example shown in FIG. 12, the second sensor chip 1222 may be configured for providing four magnetic field component values By3, By4, Bz3, Bz4 to the first sensor chip 1221, and the first sensor chip 1221 may be configured for receiving these values, and the processing circuit 1252a of the first sensor chip 1221 may be further configured for determining an absolute angular position 9 based on said eight magnetic field components. In an embodiment, the processing circuit may be configured for calculating the two sums (suml, sum2) and the two differences (diffl, diff2) described above, e.g. in accordance with the formulas shown in FIG. 2A, FIG. 2B, FIG. 5 or FIG. 7), and for determining the absolute angular position 9 based on these sums and differences.

[0295] One or both of the processing circuits 1252a, 1252b may comprise a digital processing circuit and / or a programmable processor, e.g. a CPU or a Digital Signal Processor (DSP).

[0296] Preferably each semiconductor substrate 1221, 1222 also comprises a temperature sensor (not shown), and each semiconductor substrate or sensor chip is further configured for temperature compensating the sensitivity of the magnetic sensor elements, in known manners.

[0297] The sensor device 1220 may further comprise at least one non-volatile memory (not shown), e.g. flash, which may be incorporated in the processing circuits 1252a, 1252b, or may be connected to the processing circuits 1252a, 1252b, and which may store executable instructions and / or one or more parameters, for example one or more of the following: the number of magnetic tracks (e.g. 2 or 3), the number of magnetic pole pairs of each track (e.g. Ml and N2), a look-up table for implementing the arctangent function, etc.

[0298] In some embodiments, the non-volatile memory also stores an angular offset value related to an angular offset between the magnetic poles of the first track T1 and the second track T2 of a magnetic source as in FIG. 1(a), or between the central track T1 on the one hand and the inner & outer track T2, T3 on the other hand of a magnetic source as shown in FIG. 3(a) or in FIG. 6, in case the first track T1 isnot radially aligned with the other two tracks T2, T3, but has a random or pseudo-random angular position relative to the other two tracks. This angular offset can be measured during a calibration procedure (e.g. at system-level or sub-assembly-level), and can be stored in said non-volatile memory for use during normal operation.

[0299] In the embodiment of FIG. 12, the overall angular position 9 is calculated by the processing circuit situated inside one of the sensor chips 1221, but the present invention is not limited hereto, and it is also possible that the angular position 9 is calculated outside of the sensor devices 1221, 1222, as will be described next (in FIG. 13).

[0300] It is noted that a block-diagram similar to that of FIG. 12 is also applicable for the systems of FIG. 19 and FIG. 20, except that the two semiconductor devices 1221, 1222 would not be mounted on a single PCB, but on two separate PCBs, and these two PCBs may be interconnected by means of an electrical cable. The use of two separate PCB's is of course also possible for the angular position sensor systems shown in FIG. 1 to FIG. 7, but not preferred.

[0301] FIG. 13 shows a schematic block diagram of a sensor device 1320, as can be used in angular position sensor systems proposed by the present invention, e.g. in the angular position sensor system 100 of FIG. 1(a) to FIG. 2B, and / or in the angular position sensor system 300 of FIG. 3(a) to FIG. 5, and / or in the angular position sensor system 600 of FIG. 6 and FIG. 7.

[0302] The sensor device 1320 of FIG. 13 can be seen as a variant of the sensor device 1220 of FIG. 12, the main difference being that the sensor device 1320 further comprises a processing circuit outside of the sensor chips 1321, 1322, e.g. processor 1355, communicatively connected to both semiconductor substrates or sensor chips 1321, 1322, and that each of the semiconductor substrates or sensor chips 1321, 1322 is configured for providing four magnetic field values to the processor 1355; and that the processor 1355 is configured for determining the absolute angular position 9 based on these magnetic field component values. In an embodiment, the processor 1355 is configured for calculating the two sums (suml, sum2) and the two differences (diffl, diff2) described above, e.g. in accordance with the formulas shown in any of FIG. 2A, FIG. 2B, FIG. 5 or FIG. 7), and for determining the absolute angular position 9 based on these sums and differences.

[0303] Preferably the processor 1355 is a programmable processor. Preferably the sensor device 1320 comprises at least one non-volatile memory incorporated inside, or connected to this processor 1355. Optionally the sensor device 1320 may also comprise a second non-volatile memory connected to the processing circuit 1352a, and / or a third non-volatile memory connected to the processing circuit 1352b.

[0304] In the embodiment shown in FIG. 13, the processor 1355 is communicatively connected to the two sensor chips via output circuits 1354a, 1354b, but the present invention is not limited hereto, and the processor 1355 may also be connected in another suitable manner, e.g. via a shared bus, or via two serial busses, e.g. via two SPI busses.It is noted that a block-diagram similar to that of FIG. 13 is also applicable for the systems of FIG. 19 and FIG. 20, except that the two semiconductor devices 1321, 1322 would not be mounted on a single PCB, but on two separate PCBs, and that the external processor 1355 may be mounted on one of these PCBs or on a third PCB. The PCBs may be interconnected by means of one or more electrical cables. The use of two or three separate PCB's is of course also possible for the angular position sensor systems shown in FIG. 1 to FIG. 7, but not preferred.

[0305] FIG. 14 shows a flowchart of a method 1400 of determining an absolute angular position of an angular position sensor system 100 comprising a magnetic source 110 with at least two (e.g. two or three) circular tracks (e.g. T1 and T2, or T1 and T2 and T3) and a sensor device having four sensor locations Pl to P4, e.g. as illustrated in any of FIG. 1, FIG. 2B, FIG. 3A to FIG. 5, or FIG. 6 or FIG. 7 or FIG. 19 or FIG. 20.

[0306] The method 1400 comprises the following steps:

[0307] i) optionally providing in step 1401 a magnetic source that is rotatable about a rotation axis and that comprises at least two circular tracks including a first circular track (Tl) having a first number (Ml) of magnetic pole pairs for generating a first magnetic field with a first periodicity, and a second circular track (T2) and optionally also a third circular track (T3) having a second number (N2) of magnetic pole pairs for generating a second magnetic field having a second periodicity, the first and second number (Ml, N2) being co-prime numbers, preferably one even number and one odd number;

[0308] ii) optionally providing in step 1402 a sensor device comprising a first, second, third and fourth magnetic sensor (SI, S2, S3, S4) located at four sensor locations (Pl, P2, P3, P4), optionally located on two virtual line segments which are angularly spaced apart by 180° ±10° with respect to the rotation axis, or optionally located a virtual line that passes through the centre of the magnetic source or that is located at a small distance from said centre, or optionally Pl and P2 being located on a first virtual line parallel to the rotation axis, and P3 and P4 being located on a second virtual line parallel to the rotation axis;

[0309] a) measuring in step 1403 by the first and the second magnetic sensor (SI, S2) at least one magnetic field component of the first magnetic field at the first sensor location (Pl), and measuring at least one magnetic field component of the second magnetic field at the second sensor location (Pl, P2);

[0310] c) measuring in step 1405 by the third and the fourth magnetic sensor (S3, S4) at least one magnetic field component of the first magnetic field at one of said third and fourth sensor location (P3, P4), and measuring at least one magnetic field component of the second magnetic field at the other of said third and fourth sensor location (P3, P4);

[0311] g) determining in step 1409 an angular position (9) based on the measured magnetic field components.

[0312] The method 1400 of FIG. 14 is a generic method.In an embodiment, two orthogonal magnetic field components are measured at each of said four sensor locations (Pl, P2, P3, P4), and the method further comprises the following steps:

[0313] e) determining a first and a second linear combination for each pair of parallel magnetic field components measured by the first and third magnetic sensor (SI, S3);

[0314] f) determining a third and a fourth linear combination for each pair of parallel magnetic field components measured by the second and fourth magnetic sensor (S2, S4);

[0315] and step g) comprises: determining said angular position (9) based on the first, second, third and fourth linear combination.

[0316] In an embodiment, the method further comprises the following steps:

[0317] e) determining a first and a second sum (suml, sum2) for each pair of parallel magnetic field components measured by the first and third magnetic sensor (SI, S3);

[0318] f) determining a first and a second difference (diffl, diff2) for each pair of parallel magnetic field components measured by the second and fourth magnetic sensor (S2, S4);

[0319] and step g) comprises: determining said angular position (9) based on the first and second sum (suml, sum2) and based on the first and second difference (diffl, diff2).

[0320] FIG. 15 shows a flowchart of a method 1500 of determining an absolute angular position of an angular position sensor system 100 comprising a magnetic source 110 with two circular tracks Tl, T2 and a sensor device 120 having four sensor locations Pl to P4, e.g. as illustrated in FIG. 1 and FIG. 2B, or as illustrated in FIG. 19. The method 100 comprises the following steps:

[0321] i) optionally providing in step 1501 a magnetic source that is rotatable about a rotation axis and that comprises two (e.g. concentric) circular tracks including a first circular track having a first number (Ml) of magnetic pole pairs, and a second circular track having a second number (N2) of magnetic pole pairs, the first and second number (Ml, N2) being coprime numbers, e.g. one of the first and second number (Ml, N2) being an even number, the other (N2, Ml) of the first and second number being an odd number;

[0322] ii) optionally providing in step 1502 a sensor device comprising a first, second, third and fourth magnetic sensor (SI, S2, S3, S4) located at four sensor locations (Pl, P2, P3, P4), optionally located on a virtual line that passes through the centre of the magnetic source or that is located at a small distance from said centre; or optionally Pl and P2 being located on a first virtual line parallel to the rotation axis, and P3 and P4 being located on a second virtual line parallel to the rotation axis;

[0323] a) measuring in step 1503 by the first magnetic sensor (SI) two (e.g. orthogonal) magnetic field components (e.g. Byl, Bzl) at the first sensor location (Pl) above the first track (Tl);b) measuring in step 1504 by the second magnetic sensor (S2) two (e.g. orthogonal) magnetic field components (e.g. By2, Bz2) at the second sensor location (P2) above the second track (T2);

[0324] c) measuring in step 1505 by the third magnetic sensor (S3) two (e.g. orthogonal) magnetic field components (e.g. By3, Bz3) at the third sensor location (P3) above the first track (Tl);

[0325] d) measuring in step 1506 by the fourth magnetic sensor (S4) two (e.g. orthogonal) magnetic field components (e.g. By4, Bz4) at the fourth sensor location (P4) above the second track (T2);

[0326] e) optionally determining in step 1507 a first and a second linear combination for each pair of parallel magnetic field components measured by the first and third magnetic sensor (SI, S3), e.g. a first and a second sum (suml, sum2) in accordance with the formulas: suml=(Bzl+Bz3), sum2=(Byl+By3);

[0327] f) optionally determining in step 1508 a third and a fourth linear combination for each pair of parallel magnetic field components measured by the second and fourth magnetic sensor (S2, S4), e.g. a first difference (diffl) and a second difference (diff2), e.g. in accordance with the formulas: diffl=(Bz2-Bz4), diff2=(By2-By4);

[0328] g) determining in step 1509 an angular position (9) based on the measured magnetic field components, e.g. based on the linear combinations, e.g. based on the first and second sum (suml, sum2) and based on the first and second difference (diffl, diff2).

[0329] The small distance of step ii) is for example at most 10% of the outer radius of the magnetic source, or at most 5%, or at most 2%, or at most 1%.

[0330] In an embodiment, Ml is odd and N2 is odd.

[0331] In an embodiment, Ml is even and N2 is odd.

[0332] In an embodiment, Ml is odd and N2 is even.

[0333] The tracks of the magnetic source may be axially magnetized, or may be axial-lateral (AL) magnetized, or tangentially magnetized. This is particularly suitable for a magnetic source having planar tracks (e.g. as illustrated in FIG. 1 to FIG. 7).

[0334] The tracks of the magnetic source may be radially magnetized, or may be axial-lateral (AL) magnetized, or tangentially magnetized. This is particularly suitable for a magnetic source having cylindrical tracks (e.g. as illustrated in FIG. 19 or FIG. 20).

[0335] One magnetic field component may be oriented in the axial direction of the magnetic source, the other magnetic field component may be oriented in a circumferential direction of the magnetic source. This is particularly suitable for a magnetic source having planar tracks.

[0336] One magnetic field component may be oriented in the radial direction of the magnetic source, the other magnetic field component may be oriented in a circumferential direction of the magnetic source. This is particularly suitable for a magnetic source having cylindrical tracks.

[0337] The method may further comprise: converting the two sum signals into a first set of quadrature signals, and converting the two difference signals into a second set of quadrature signals, and deriving a first angle 9M from the first set of quadrature signals, and deriving a second angle 9N from the secondset of quadrature signals, and deriving the angular position 9 from the first angle 9M and the second angle 9N.

[0338] FIG. 16 shows a flowchart of a method 1600 of determining an absolute angular position of an angular position sensor system 300 comprising a magnetic source 310 with three circular tracks Tl, T2, T3, and a sensor device 320 having four sensor locations Pl to P4, e.g. as illustrated in FIG. 3(a) to FIG. 5, or as illustrated in FIG. 20. The method 1500 comprises the following steps:

[0339] i) optionally providing in step 1601 a magnetic source that is rotatable about a rotation axis and that comprises three concentric circular tracks including a first (e.g. central) track (Tl) having a first number (Ml) of magnetic pole pairs, and a second (e.g. inner) track (T2) and a third (e.g. outer) track (T3) both having a second number (N2) of magnetic pole pairs; the first and second number (Ml, N2) being coprime numbers, e.g. one of the first and second number (Ml, N2) being an even number, the other (N 2, Ml) of the first and second number being an odd number;

[0340] ii) optionally providing in step 1602 a sensor device comprising a first, second, third and fourth magnetic sensor (SI, S2, S3, S4) located at four sensor locations (Pl, P2, P3, P4), optionally located on a virtual line that passes through the centre of the magnetic source or that is located at a small distance from said centre; or optionally Pl and P2 being located on a first virtual line parallel to the rotation axis, and P3 and P4 being located on a second virtual line parallel to the rotation axis;

[0341] a) measuring in step 1603 by the first magnetic sensor (SI) two (e.g. orthogonal) magnetic field components (e.g. Byl, Bzl) at the first sensor location (Pl) above the first track (Tl);

[0342] b) measuring in step 1604 by the second magnetic sensor (S2) two (e.g. orthogonal) magnetic field components (e.g. By2, Bz2) at the second sensor location (P2) above the second track (T2);

[0343] c) measuring in step 1605 by the third magnetic sensor (S3) two (e.g. orthogonal) magnetic field components (e.g. By3, Bz3) at the third sensor location (P3) above the first track (Tl);

[0344] d) measuring in step 1606 by the fourth magnetic sensor (S4) two (e.g. orthogonal) magnetic field components (e.g. By4, Bz4) at the fourth sensor location (P4) above the third track (T3);

[0345] e) optionally determining in step 1607 a first and a second linear combination for each pair of parallel magnetic field components measured by the first and third magnetic sensor (SI, S3), e.g. a first and a second sum (suml, sum2) in accordance with the formulas: suml=(Bzl+Bz3), sum2=(Byl+By3);

[0346] f) optionally determining in step 1608 a third and a fourth linear combination for each pair of parallel magnetic field components measured by the second and fourth magnetic sensor (S2, S4), e.g. a first difference (diffl) and a second difference (diff2), e.g. in accordance with the formulas: diffl=(Bz2-Bz4), diff2=(By2-By4);

[0347] g) determining in step 1609 an angular position (9) based on the measured magnetic field components, e.g. based on the linear combinations, e.g. based on the first and second sum (suml, sum2) and based on the first and second difference (diffl, diff2).The small distance of step ii) is for example at most 10% of the outer radius of the magnetic source, or at most 5%, or at most 2%, or at most 1%.

[0348] In an embodiment Ml is even, and N2 is odd. FIG. 3 to FIG. 5 show such an embodiment, with Ml=8 and N2=7, but other values of Ml and N2 can also be used.

[0349] In an embodiment, Ml is odd and N2 is odd.

[0350] In an embodiment, Ml is odd and N2 is even.

[0351] The tracks of the magnetic source may be axially magnetized, or may be axial-lateral (AL) magnetized, or tangentially magnetized. This is particularly suitable for a magnetic source having planar tracks (e.g. as illustrated in FIG. 1 to FIG. 7).

[0352] The tracks of the magnetic source may be radially magnetized, or may be axial-lateral (AL) magnetized, or tangentially magnetized. This is particularly suitable for a magnetic source having cylindrical tracks (e.g. as illustrated in FIG. 19 or FIG. 20).

[0353] One magnetic field component may be oriented in the axial direction of the magnetic source, the other magnetic field component may be oriented in a circumferential direction of the magnetic source. This is particularly suitable for a magnetic source having planar tracks.

[0354] One magnetic field component may be oriented in the radial direction of the magnetic source, the other magnetic field component may be oriented in a circumferential direction of the magnetic source. This is particularly suitable for a magnetic source having cylindrical tracks.

[0355] The method may further comprise: converting the two sum signals into a first set of quadrature signals, and converting the two difference signals into a second set of quadrature signals, and deriving a first angle 9M from the first set of quadrature signals, and deriving a second angle 0N from the second set of quadrature signals, and deriving the angular position 9 from the first angle 9M and the second angle 9N.

[0356] FIG. 17 shows a flowchart of a method 1700 of determining an absolute angular position of an angular position sensor system comprising a magnetic source with three circular tracks and a sensor device having four sensor locations Pl to P4, e.g. as illustrated in FIG. 6 to FIG. 7, or as illustrated in FIG. 20. The method comprises the following steps:

[0357] i) optionally providing in step 1701 a magnetic source that is rotatable about a rotation axis and that comprises three circular tracks including a first (e.g. central) track (Tl) having a first number (Ml) of magnetic pole pairs, and a second (e.g. inner) track (T2) and a third (e.g. outer) track (T3) both having a second number (N2) of magnetic pole pairs; the first and second number (Ml, N2) being coprime numbers, e.g. one of the first and second number (Ml, N2) being an even number, the other (N2, Ml) of the first and second number being an odd number;

[0358] ii) optionally providing in step 1702 a sensor device comprising a first, second, third and fourth magnetic sensor (SI, S2, S3, S4) located at four sensor locations (Pl, P2, P3, P4), optionally located on avirtual line that passes through the centre of the magnetic source or that is located at a small distance from said centre; or optionally Pl and P2 being located on a first virtual line parallel to the rotation axis, and P3 and P4 being located on a second virtual line parallel to the rotation axis;

[0359] a) measuring in step 1703 by the first magnetic sensor (SI) two (e.g. orthogonal) magnetic field components (e.g. Byl, Bzl) at the first sensor location (Pl) above the second track (T2);

[0360] b) measuring in step 1704 by the second magnetic sensor (S2) two (e.g. orthogonal) magnetic field components (e.g. By2, Bz2) at the second sensor location (P2) above the first track (Tl);

[0361] c) measuring in step 1705 by the third magnetic sensor (S3) two (e.g. orthogonal) magnetic field components (e.g. By3, Bz3) at the third sensor location (P3) above the third track (T3);

[0362] d) measuring in step 1706 by the fourth magnetic sensor (S4) two (e.g. orthogonal) magnetic field components (e.g. By4, Bz4) at the fourth sensor location (P4) above the first track (Tl);

[0363] e) optionally determining in step 1707 a first and a second linear combination for each pair of parallel magnetic field components measured by the first and third magnetic sensor (SI, S3), e.g. a first and a second sum (suml, sum2) in accordance with the formulas: suml=(Bzl+Bz3), sum2=(Byl+By3);

[0364] f) optionally determining in step 1708 a third and a fourth linear combination for each pair of parallel magnetic field components measured by the second and fourth magnetic sensor (S2, S4), e.g. a first difference (diffl) and a second difference (diff2), e.g. in accordance with the formulas: diffl=(Bz2-Bz4), diff2=(By2-By4);

[0365] g) determining in step 1709 an angular position (9) based on the measured magnetic field components, e.g. based on the linear combinations, e.g. based on the first and second sum (suml, sum2) and based on the first and second difference (diffl, diff2).

[0366] The small distance of step ii) is for example at most 10% of the outer radius of the magnetic source, or at most 5%, or at most 2%, or at most 1%.

[0367] In an embodiment Ml is odd, and N2 is even. FIG. 6 and FIG. 7 show such an embodiment, with Ml=7 and N2=8, but other values of Ml and N2 can also be used.

[0368] In an embodiment, Ml is odd and N2 is odd.

[0369] In an embodiment, Ml is odd and N2 is even.

[0370] The tracks of the magnetic source may be axially magnetized, or may be axial-lateral (AL) magnetized, or tangentially magnetized. This is particularly suitable for a magnetic source having planar tracks (e.g. as illustrated in FIG. 1 to FIG. 7).

[0371] The tracks of the magnetic source may be radially magnetized, or may be axial-lateral (AL) magnetized, or tangentially magnetized. This is particularly suitable for a magnetic source having cylindrical tracks (e.g. as illustrated in FIG. 19 or FIG. 20).

[0372] One magnetic field component may be oriented in the axial direction of the magnetic source, the other magnetic field component may be oriented in a circumferential direction of the magnetic source. This is particularly suitable for a magnetic source having planar tracks.One magnetic field component may be oriented in the radial direction of the magnetic source, the other magnetic field component may be oriented in a circumferential direction of the magnetic source. This is particularly suitable for a magnetic source having cylindrical tracks.

[0373] The method may further comprise: converting the two sum signals into a first set of quadrature signals, and converting the two difference signals into a second set of quadrature signals, and deriving a first angle 9M from the first set of quadrature signals, and deriving a second angle 0N from the second set of quadrature signals, and deriving the angular position 9 from the first angle 9M and the second angle 9N.

[0374] FIG. 18A shows an example of a magnetic source 1810 comprising three concentric circular tracks: a first track or central track Tl, a second track or inner track T2, and a third track or outer track T3. The first track Tl has a first number Ml of magnetic pole pairs. The second track T2 has a second number N2 of magnetic pole pairs different from the first number (thus Ml * N2). The third track T3 has a third number N3 of magnetic pole pairs, equal to N2 (thus N3=N2). The magnetic poles of the second track and the third track are radially aligned.

[0375] The numbers Ml and N2 are coprime numbers, or relatively prime or mutually prime, i.e. the greatest common divisor (GCD) of Ml and N2 is 1.

[0376] In an embodiment, Ml is odd and N2 is odd.

[0377] In an embodiment, one of the first and second number (Ml, N2) is an even number, and the other of said first and second number is an odd number.

[0378] In an embodiment, Ml is even and N2 is odd.

[0379] In an embodiment, Ml is odd and N2 is even.

[0380] In an embodiment, each of Ml and N2 is larger than 3 and smaller than 32, or larger than 6 and smaller than 24, or larger than 8 and smaller than 20.

[0381] In an embodiment, M1=(N2+1), or M1=(N2-1), or Ml=(N2+2), or Ml=(N2-2), or Ml=(N2+3), or Ml=(N2-3).

[0382] In an embodiment, Ml=14 pole pairs, and N2=13 pole pairs, and the magnetic source has an inner diameter in the range from 25 mm to 50 mm, and an outer diameter that is 8 mm to 14 mm larger than the inner diameter.

[0383] In an embodiment, Ml=13 pole pairs, and N2=14 pole pairs, and the magnetic source has an inner diameter in the range from 25 mm to 50 mm, and an outer diameter that is 8 mm to 14 mm larger than the inner diameter.

[0384] In the example shown in FIG. 18A, the inner track T2 has an inner radius R1 and an outer radius R2, the central track Tl has an inner radius R2 and an outer radius R3, and the outer track T3 has an inner radius R3 and an outer radius R4. The width wl of the first track Tl, measured in the radial directionis equal to (R3-R2). The width w2 of the second trackT2, measured in the radial direction is equal to (R2-Rl). The width w3 of the third track T3, measured in the radial direction is equal to (R4-R3).

[0385] In a variant (not shown), the tracks are separated by a non-coded region, e.g. by a groove which may be filled with a non-magnetic material such as e.g. Aluminum.

[0386] In an embodiment, the magnetic source has an inner diameter (i.e. the inner diameter of the second track) in the range from 25 mm to 50 mm, and an outer diameter (i.e. the outer diameter of the third track) that is 8 mm to 14 mm larger than the inner diameter.

[0387] The first circular track T1 has a fixed angular offset relative to the second track T2, and thus also to the third track T3. This angular offset may be a predefined value (e.g.0°), or may be a pseudo-random value, depending on how the magnetic source is produced. If the angular offset is a predefined value, equal to zero or different from zero, this angular offset value is also taken into account in the methods described above, e.g. in step g) of the method 1400, 1500, 1600, 1700 of FIG. 14 to FIG. 17.

[0388] Such a magnetic source can e.g. be produced by first making a magnetic source having a U-shaped cross-section, where the two legs of the U-shape form the second and the third track, and where a groove is formed between these legs for receiving a central ring. Angular alignment of the central ring (=first track) with the U-shape can e.g. be accomplished by using a central ring with one or more protrusions that engage in corresponding holes or cavities or openings or blind holes or grooves of the U-shape, or vice versa (i.e. the U-shape having protrusions, and the central ring having holes or openings or cavities or grooves).

[0389] But that is not absolutely required, and in an embodiment, the central track T1 may have a pseudo-random angular offset relative to the inner T2 and outer track T3. When the latter magnetic source is used in a sensor system as described above, the unknown pseudo-random angular offset can be determined during a calibration procedure, and stored in a non-volatile memory of the sensor device, e.g. inside one of the sensor chips, or in the non-volatile memory of a processing circuit connected to the two sensor devices, or connected to a processor outside of the sensor devices, and can be taken into account in step g).

[0390] In an embodiment, the first track (Tl) has a first width "wl", the second track (T2) has a second width "w2", and the third track (T3) has a third width "w3", and wl is larger than w2, and wl is larger than w3, or written mathematically: (wl>w2) and (wl>w3).

[0391] In an embodiment the second track width w2 is substantially equal to the third track width w3 (e.g. within a predefined tolerance margin), or written mathematically: (w2 / w3) is a value in the range from 0.75 to 1.25, or in the range from 0.80 to 1.20, or in the range from 0.90 to 1.10.

[0392] In an embodiment, (wl / w2) > 1.25 and (wl / w3) > 1.25.

[0393] In an embodiment, (wl / w2) > 1.5 and (wl / w3) > 1.5.

[0394] In an embodiment, (wl / w2) > 1.75 and (wl / w3) > 1.75.

[0395] In an embodiment, (wl / w2) > 2.0 and (wl / w3) > 2.0.In an embodiment, (wl / w2) > 2.5 and (wl / w3) > 2.5.

[0396] In an embodiment, wl is a value in the range of 2.0 to 4.0 mm, or in the range from 2.25 to 3.75 mm, or in the range from 2.50 to 3.50 mm, or in the range from 2.75 to 3.25 mm.

[0397] In an embodiment, a ratio (w2 / wl) is a value in the range from 15% to 70%, or 15% to 60%, or 15% to 50%, or 15% to 40%, or 15% to 30%.

[0398] In an embodiment, wl is a value in the range from 2.0 to 4.0 mm, and each of w2 and w3 is a value in the range from 0.50 to 1.5 mm (or in the range from 0.75 to 1.25 mm).

[0399] In an embodiment, each of said first, second and third track is axially magnetized, e.g. as illustrated in FIG. 18B).

[0400] In an embodiment, each of said first, second and third track is axial-lateral (AL) magnetized, or tangentially magnetized, e.g. as illustrated in FIG. 18C.

[0401] In an embodiment, the inner and outer track are axially magnetized, and the central track is axial-lateral (AL) or tangentially magnetized.

[0402] In an embodiment, the central track is axially magnetized, and the inner and outer track are axial-lateral (AL) or tangentially magnetized.

[0403] FIG. 19 shows an illustrative example of an angular position sensor system 1900, comprising a magnetic source 1910 with two cylindrical tracks Tl, T2. The angular position sensor system 1900 can be seen as a variant of the angular position sensor system 100 of FIG. 1(a). The main differences being that:

[0404] i) the tracks Tl, T2 are located on a cylindrical surface, and have a same outer radius Ro; ii) the track widths wl and w2 are measured in the axial direction;

[0405] iii) the two semiconductor substrates or sensor chips 1821, 1822 are located at a radial position larger than the outer radius Ro of the magnetic source 1810;

[0406] iv) the magnetic source may be radially magnetized, or tangentially magnetized;

[0407] v) the magnetic sensors SI to S4 are preferably configured for measuring one magnetic field component oriented in the radial direction of the magnetic source (Bz relative to the semiconductor substrate), and one magnetic field component oriented in a circumferential direction (By relative to the semiconductor substrate);

[0408] vi) the sensor locations Pl, P2 may be located on a first virtual line oriented in the axial direction of the magnetic source (the X-direction of the semiconductor substrate), and the sensor locations P3, P4 may be located on a second virtual line oriented in the axial direction;

[0409] vii) the semiconductor substrates or sensor chips 1821, 1822 may be mounted to a first and a second printed circuit board (not shown), and these PCB's may be mounted to a housing or a chassis (not shown), e.g. symmetrically with respect to the rotation axis.Everything else described above for FIG. 1(a) to FIG. 2B and variants thereof, is also applicable here, mutatis mutandis, for example:

[0410] - the first track T1 may contain a first number (Ml) of magnetic pole pairs, and the second track may contain a second number (N2) of magnetic pole pairs, where Ml and N2 are coprime numbers. In an embodiment, Ml is even, and N2 is odd. In an embodiment, Ml is odd and N2 is even. In an embodiment, Ml is odd and N2 is also odd;

[0411] - the width wl of the first track T1 may be substantially equal to the width w2 of the second track T2 (within a tolerance margin of ±25%, or ±20%, or ±15%, or ±10%, or ±5%);

[0412] - the same formulas mentioned above, in FIG. 2A or FIG. 2B, e.g. depending on the positions of the sensors, can be used to determine an absolute angular position of the magnetic source relative to the sensor devices 1921, 1922, or e.g. relative to the chassis or housing they are mounted to;

[0413] - the absolute position may be calculated by a processing circuit inside one (or both) of the sensor devices 1921, 1922 (e.g. in a manner similar to FIG. 12), or by an external processor (not shown in FIG. 19, but see e.g. FIG. 13) mounted on the same PCB that also contains the first sensor device 1921, for example.

[0414] In the embodiment shown in FIG. 19, SI and S3 are located above Tl, and S2 and S4 are located above T2. This corresponds to the arrangement of FIG. 2A, and the same formulas are applicable.

[0415] FIG. 20 shows an illustrative example of an angular position sensor system 2000, comprising a magnetic source 2010 with three cylindrical tracks Tl, T2, T3. The angular position sensor system 2000 can be seen as a variant of the angular position sensor system 300 of FIG. 3(a) and / or as a variant of the system 600 of FIG. 6, and / or as a further variant of the angular position sensor system 1900 of FIG. 19.

[0416] The main difference between the system 2000 of FIG. 20 and the system 1900 of FIG. 19 is that the magnetic source comprises three tracks instead of two, and that the semiconductor substrates 2021, 2022 are preferably mounted at different axial positions (i.e. axially offset), hence asymmetrically with respect to the rotation axis.

[0417] Similarly to the embodiments of the magnetic source with three cylindrical tracks illustrated in Figs.5-7, the sensor locations Pl, P2 may be located on a first virtual line oriented in the axial direction of the magnetic source (the X-direction of the semiconductor substrate), and the sensor locations P3, P4 may be located on a second virtual line oriented in the axial direction.

[0418] Pl and P2 are located on one side of the lateral surface of the magnetic source, P3 and P4 on the other side of the surface. As can be seen, P2 and P3 are situated substantially above the central track Tl, P4 is located above or in vicinity of the track T2, and Pl is located above or in vicinity of the track T3, so as to be more robust against (axially) mounting position offset and / or against an axially shifting of the magnetic source.In a variant (not shown) of FIG. 20, Ml is even, N2 is odd, SI and S3 are located above Tl, S2 is located above T2 and S4 is located above T3. This corresponds to the arrangement of FIG. 5, and the same formulas are applicable.

[0419] In another variant (not shown), Ml is odd, N2 is even, S2 and S4 are located above Tl, SI is located above T2, and S3 is located above T3. This corresponds to the arrangement of FIG. 7, and the same formulas are applicable.

[0420] FIG. 21 shows an example of a magnetic source 2110 comprising three cylindrical tracks, as may be used in the angular position sensor system 2000 of FIG. 20.

[0421] The first track T1 has a first number Ml of magnetic pole pairs. The second track T2 has a second number N2 of magnetic pole pairs different from the first number (thus Ml * N2). The third track T3 has a third number N3 of magnetic pole pairs, equal to N2 (thus N3=N2). The magnetic poles of the second track and the third track are radially aligned.

[0422] The numbers Ml and N2 are coprime numbers, or relatively prime or mutually prime, i.e. the greatest common divisor (GCD) of Ml and N2 is 1.

[0423] In an embodiment, Ml is odd and N2 is odd.

[0424] In an embodiment, Ml is even and N2 is odd.

[0425] In an embodiment, Ml is odd and N2 is even.

[0426] In an embodiment, each of Ml and N2 is larger than 3 and smaller than 32, or larger than 6 and smaller than 24, or larger than 8 and smaller than 20.

[0427] In an embodiment, M1=(N2+1), or M1=(N2-1), or Ml=(N2+2), or Ml=(N2-2), or Ml=(N2+3), or Ml=(N2-3).

[0428] In an embodiment, Ml=14 pole pairs, and N2=13 pole pairs, or vice versa.

[0429] In an embodiment, the first track (Tl) has a first width "wl", the second track (T2) has a second width "w2", and the third track (T3) has a third width "w3", and wl is larger than w2, and wl is larger than w3, or written mathematically: (wl>w2) and (wl>w3).

[0430] In an embodiment the second track width w2 is substantially equal to the third track width w3 (e.g. within a predefined tolerance margin), or written mathematically: (w2 / w3) is a value in the range from 0.75 to 1.25, or in the range from 0.80 to 1.20, or in the range from 0.90 to 1.10.

[0431] In an embodiment, (wl / w2) > 1.25 and (wl / w3) > 1.25.

[0432] In an embodiment, (wl / w2) > 1.5 and (wl / w3) > 1.5.

[0433] In an embodiment, (wl / w2) > 1.75 and (wl / w3) > 1.75.

[0434] In an embodiment, (wl / w2) > 2.0 and (wl / w3) > 2.0.

[0435] In an embodiment, (wl / w2) > 2.5 and (wl / w3) > 2.5.

[0436] In an embodiment, wl is a value in the range of 2.0 to 4.0 mm, or in the range from 2.25 to 3.75 mm, or in the range from 2.50 to 3.50 mm, or in the range from 2.75 to 3.25 mm.In an embodiment, a ratio (w2 / wl) is a value in the range from 15% to 70%, or 15% to 60%, or 15% to 50%, or 15% to 40%, or 15% to 30%.

[0437] In an embodiment, wl is a value in the range from 2.0 to 4.0 mm, and each of w2 and w3 is a value in the range from 0.50 to 1.5 mm (or in the range from 0.75 to 1.25 mm).

[0438] Previously described embodiments concern an angular position system able or configured to determine an angular position of the magnetic source within a full angular range, i.e. the measurement range of the described angular position sensor systems is 360°, as the greatest common divisor (GCD) of Ml and N2 is 1.

[0439] According to another aspect of the invention, the invention also concerns angular position systems having a measurement range that is a fraction of the full angular range.

[0440] The inventors also noticed that the previously described technical teaching for reducing or eliminating the cross-talk interferences can also be applied to these systems, e.g. by applying the same poles arrangements of the magnetic source and the same relative positioning of the sensor locations to fractions of 360°.

[0441] According to such aspect of the invention, the angular position sensor system for determining an angular position of a magnetic source relative to a sensor device can thus comprise a magnetic source rotatable about a rotation axis, the magnetic source comprising at least two circular tracks (T1,T2; T1,T2,T3), including :

[0442] -a first circular track (Tl) having a first number (Ml) of magnetic pole pairs for generating a first magnetic field having a first magnetic field pattern periodicity with respect to said rotation axis (e.g. a periodically repetitive first magnetic field pattern with respect to the rotation axis), and

[0443] -a second circular track (T2) and optionally also a third circular track (T3) having a second number (N2) of magnetic poles pairs for generating a second magnetic field having a second magnetic field pattern periodicity with respect to said rotation axis (e.g. a periodically repetitive second magnetic field pattern with respect to the rotation axis).

[0444] As for the above described systems, the angular position sensor system comprises a sensor device movable relative to the magnetic source, or vice versa; the sensor device comprising four magnetic sensors including a first, second, third and fourth magnetic sensor situated at four different sensor locations, each magnetic sensor configured for measuring at least one but preferably two magnetic field components oriented in different directions, preferably orthogonal directions. One of the first and second sensor location is arranged for measuring the first magnetic field, and the other of the first and second sensor location is arranged for measuring the second magnetic field. One of the third and fourth sensor location is arranged for measuring the first magnetic field, and the other of the third and fourth sensor location is arranged for measuring the second magnetic field. The angular position sensor system further comprises a processing circuit configured for determining an absolute angular position (9) of the magnetic source relative to the sensor device based on the magnetic field componentsmeasured by the four magnetic sensors (SI, S2, S3, S4), notably configured for combining said measured magnetic field components of the first magnetic field to a first track signal for at least reducing, preferably eliminating, disturbance from the second magnetic field (e.g. cross-talk between the magnetic tracks), for combining said measured magnetic field components of the second magnetic field to a second track signal for at least reducing, preferably eliminating, disturbance from the first magnetic field, and for determining said angular position (9) based on said first and second track signal.

[0445] According to this aspect of the invention, the measuring range of the system can be 360° or a fraction thereof. In fact, the measuring range is then determined by the number of replications of the above described odd and pair magnetic poles pairs arrangement of the magnetic source, that is indicated by the greatest common divisor GCD (or greatest common factor GCF, i.e. the largest positive integer that divides each of the two integers) of the first and second number (Ml, N2). In case of a GDC of one, i.e. a simple odd and even magnetic pole pairs arrangement (as previously described and exemplary illustrated by Figures 1,3,5-7,18-21) the measurement range can reach 360°. In case of a GCD of 2, i.e. a simple duplication of the odd and even magnetic pole pairs arrangement around the magnetic source, the measurement range of the angular position system will then be reduced to a half turn (180°, i.e.

[0446] 360° / GCD). A triple arrangement will be characterized by a GCD of 3 and the measurement range will be limited to 120°.

[0447] The relative positioning of the first, second, third and fourth sensor location depends thus on the greatest common divisor GCD of the first (Ml) and second number (N2). The first and the third sensor location can advantageously angularly spaced by a first angle with respect to the rotation axis; while the second and the fourth sensor location are angularly spaced by a second angle with respect to the rotation axis, each of said first and second angle being substantially equal to a product of an odd integer number multiplied to 180° divided by the greatest common divisor (i.e. i-180° / GCD , where the factor "i" is an odd integer number), notably within a tolerance margin (e.g. a tolerance margin of % pole angular size, or ±10°, or ±7°, or ±5°, or ±4°, or ±3°, or ±2°, or ±1°). The second angle can be equal to or different of the first angle.

[0448] The same aspect of the invention also concerns a related method of determining an angular position of a magnetic source relative to a sensor device, wherein the measuring range is equal to 360° or a fraction thereof, the method comprising:

[0449] a) measuring by the sensor device at least one magnetic field component of the first magnetic field at two positions around the rotation axis, one angularly spaced from the other by the first angle with respect to the rotation axis;

[0450] c) measuring by the sensor device at least one magnetic field component of the second magnetic field at two positions around the rotation axis, one angularly spaced from the other by the second angle with respect to the rotation axis;g) determining an angular position (9) based on the measured magnetic field components, notably comprising:

[0451] combining said measured magnetic field components of the first magnetic field to a first track signal for at least reducing, preferably eliminating, disturbance from the second magnetic field (e.g. cross-talk between the magnetic tracks), and

[0452] for combining said measured magnetic field components of the second magnetic field to a second track signal for at least reducing, preferably eliminating, disturbance from the first magnetic field, and

[0453] for determining said angular position (9) based on said first and second track signal.

[0454] These solutions mitigate up to eliminate cross-talk disturbance in magnetic field components used to determine the relative angular position between the magnetic source and the sensor device , not only for systems having a measuring range of 360° but also for systems having a measuring range of a fraction of 360°, as exploiting simple combinations of couple of measure at two points where the magnetic source relatively present a particular inter-poles arrangement.

[0455] In fact, at these relative positioning, the sensors assigned to one of the first and the second magnetic fields are (always) each faced to a same polarized magnetic pole with a similar magnetic field intensity (as the number of pole pairs divided by the greatest common divisor is odd), while the sensors assigned to the other of the first and the second magnetic field are (always) faced to opposed or inversed polarized poles with similar magnetic field intensities (as the number of pole pairs divided by the greatest common divisor is even).

[0456] The inventors noticed that due to this particular situation between the first and the second magnetic field, the cross-talk disturbances at these positions are both similar but with opposed direction, i.e. the disturbance of the other magnetic field being additive at one point, destructive at the other point. A simple combination (such as an addition or a subtraction) of measurement at these two positions can thus remove up to eliminate the cross-talk from measurement of the magnetic field components to be used to determine the angular position, leading to a more accurate angle determination.

[0457] About particular embodiments, everything else described above about system having a measuring range of 360° is also applicable here, mutatis mutandis, for example a magnetic source having a third track, arranged either radially or axially.

[0458] In fact, in preferred embodiments the magnetic source also comprises a third circular track (axially or radially) arranged so as the first track is located between the second track and the third track, and one of the two sensors sensing the second magnetic field is located in the vicinity of the second circular track and the other in the vicinity of the third circular track (e.g. as exemplarily illustrated in Figs.

[0459] 3,6,7 and 20). These embodiments are also effective for providing magnetic field components being more robust to axially or radially inaccuracies and / or displacements between the magnetic source andthe sensor device, even for system having a measuring range equal to a fraction of 360°, as a magnetic intensity decrease of a sensed component of one magnetic field due to such inaccuracies is generally coupled by a magnetic intensity increase of the other sensed component of the same magnetic field.

[0460] Even if the illustrated embodiments of the angular position sensor system, device and magnetic source are related to a magnetic source having a first circular track with a first number (Ml) of magnetic pole pairs and a second (eventually even a third) circular track(s) having a second number (N2) of magnetic pole pairs, the first and the second number being co-prime (i.e. the greatest common divisor of the first number (Ml) and the second number (N2) is equal to 1), the invention is not limited to a such arrangement that may provide an (unique) angle determination up to a full mechanical turn of the magnetic source.

[0461] The invention may also provide an angular position sensor system, device and magnetic source providing a position measurement up to a portion of a full mechanical turn. In such arrangements, the magnetic source comprising a first circular track with a first number (Ml) of magnetic pole pairs and a second (eventually even a third) circular track(s) having a second number (N2) of magnetic pole pairs, the first and the second number being not co-prime, i.e. the first number (Ml) and the second number ( N2) having a greatest common divisor greater than 1. Such anguler position sensor system may provide an angle determination up to a portion of the full mechanical turn (e.g. up to an angular measurement range corresponding to a full angle divided by the greatest common divisor of the first and the second number of pole pairs).

[0462] In this non-coprime arrangement, the pairs of magnetic sensors allocated to sense the same magnetic field (e.g. the first and third sensor locations pair, and the second and the fourth sensor locations pair) may be angular spaced by either the first or the second angle, each angle being substantially equal to an odd multiple of a straight angle divided by the greatest common divisor of the first and the second number. In other words, the first and / or the second angle may correspond to a product of an odd integer number multiplied to 180° (e.g. with a tolerance margin). In some arrangement, the second angle may correspond or differ to the first angle. In some embodiments, the first sensor location may be axially or radially aligned with one of the second and fourth sensor location, and / or the third sensor location may be axially or radially aligned with the other one of the second and fourth sensor location.

[0463] In some embodiments, the greatest common divisor may be 2. The measuring range is thus limited to (up to) a straight mechanical angle. The first number (Ml) of magnetic pole pairs and the second number (N2) may be : Ml=4 and N2=6, Ml=6 and N2=10, Ml=10 and N2=14, Ml=14 and N2=18, Ml=18 and N2=22, Ml=22 and N2=26, Ml=26 and N2=30, Ml=30 and N2=34, Ml=34 and N2=38, or vice versa for any of these examples. The second number N2 may an even number and the first number Ml may be Ml=N2+2 or Ml=N2-2, e.g. Ml=16 and N2=14, or Ml=18 and N2=16, or Ml=20 and N2=18, or vice versa for any of these examples. In these embodiments, each of the first and the second anglemay be either a right angle (e.g. substantially 90°) or a sum of three right angle (e.g. substantially 90°+90°+90°) for disposing of the above described effect of the invention. In fact, these sensor locations arrangements provide couples of sensor signals, each comprising one similar signal indicative of one of the (sensed) first and second magnetic field as well as one opposite (e.g. inversed) signal indicative of the other of the (sensed) first and second magnetic field. By an additive or subtractive combination of such couple of signals, the unwanted signal (e.g. crosstalk) can be reduced, or even removed from the combined signal.

[0464] In other embodiments, the greatest common divisor may be 3. The measuring range is thus limited to (up to) a 120° mechanical angle. The first number (Ml) of magnetic pole pairs and the second number (N2) may be: Ml=6 and N2=9, Ml=9 and N2=15, Ml=15 and N2=21, Ml=21 and N2=27, Ml=27 and N2=33, Ml=33 and N2=39, Ml=39 and N2=45, Ml=45 and N2=51, Ml=51 and N2=57, or vice versa for any of these examples. The second number N2 may be a multiple of 3 and the first number Ml may be Ml=N2+3 or Ml=N2-3, e.g. Ml=24 and N2=21, or Ml=27 and N2=24, or Ml=30 and N2=27, or vice versa for any of these examples. In these embodiments, each of the first and the second angle may one of : a 60° angle, a 180° angle, and a 300° angle, so as to dispose of couples of similar and opposite sensor signals indicative of the (sensed) first and second magnetic field. By an additive or subtractive combination of such couple of signals, the unwanted signal (e.g. crosstalk) can be thus reduced, or even removed from the combined signal.

[0465] In other embodiments, the greatest common divisor may be greater than 3, e.g. 4 (measuring range limited up to a 90° mechanical angle), 5 (measuring range limited up to a 72° mechanical angle), 6 (measuring range limited up to a 60° mechanical angle), or even 12 (measuring range limited up to a 30° mechanical angle).

[0466] REFERENCE NUMERALS

[0467] (modulo 100)

[0468] -00 angular position sensor system -10 magnetic source

[0469] -20 magnetic sensor device (e.g. PCB with two semiconductor substrates / chips)

[0470] -21 first semiconductor substrate / integrated circuit / sensor chip

[0471] -22 second semiconductor substrate / integrated circuit / sensor chip

[0472] -51 biasing and readout circuit -52 processing circuit

[0473] -53 communication interface -54 output circuit;

[0474] -55 (external) processor

[0475] Pl, P2, P3, P4 first, second, third, fourth sensor position

[0476] SI, S2, S3, S4 first, second, third, fourth magnetic sensor (e.g. 2D magnetic pixel)

[0477] Tl, T2, T3 first, second, third circular track

Claims

1. 58Claims1. An angular position sensor system (100; 300; 600; 1900; 2000) comprising:- a magnetic source (110; 310; 610; 1910; 2010) rotatable about a rotation axis,the magnetic source comprising at least two circular tracks (T1,T2; T1,T2,T3), including a first circular track (Tl) having a first number (Ml) of magnetic pole pairs for generating a first magnetic field having a first periodicity, and a second circular track (T2) and optionally also a third circular track (T3) having a second number (N2) of magnetic pole pairs for generating a second magnetic field having a second periodicity;wherein a first quotient of the first number (Ml) divided by a greatest common divisor of the first and the second number (M1,N2) is an even number, and a second quotient of the second number (N2) divided by said greatest common divisor is an odd number, or vice versa;- a sensor device (120; 320; 620) movable relative to the magnetic source, or vice versa; wherein the sensor device comprises four magnetic sensors including a first, second, third and fourth magnetic sensor (SI, S2, S3, S4) situated at four different sensor locations (Pl, P2, P3, P4), each magnetic sensor configured for measuring at least one but preferably two magnetic field components oriented in different directions (Byl,By2,By3,By4; Byl,Bzl,By2,Bz2,By3,Bz3,By4,Bz4);wherein the first and the third sensor location (Pl, P3) are angularly spaced by a first angle with respect to the rotation axis;and wherein the second and the fourth sensor location (P2, P4) are angularly spaced by a second angle with respect to the rotation axis;wherein one of the first and second sensor location (Pl, P2) is arranged for measuring the first magnetic field, and the other of the first and second sensor location (P2, Pl) is arranged for measuring the second magnetic field;wherein one of the third and fourth sensor location (P3, P4) is arranged for measuring the first magnetic field, and the other of the third and fourth sensor location (P4, P3) is arranged for measuring the second magnetic field;- a processing circuit configured for determining an absolute angular position (9) of the magnetic source relative to the sensor device based on the magnetic field components (Byl,By2,By3,By4; Byl,Bzl,By2,Bz2,By3,Bz3,By4,Bz4) measured by the four magnetic sensors (SI, S2, S3, S4).

2. An angular position sensor system (100; 300; 600; 1900; 2000) according to claim 1, wherein each of the first angle and the second angle corresponds to an odd multiple of a straight angle divided by the greatest common divisor of the first and the second number.

3. An angular position sensor system (100; 300; 600; 1900; 2000) according to claim 1 or 2,59wherein the greatest common divisor of the first number (Ml) and the second number (N2) is equal to 1, and each of the first angle and the second angle is a straight angle; and wherein :the first number (Ml) of pole pairs is an even number, and the second number (N2) of pole pairs is an odd number; orthe first number (Ml) of pole pairs is an odd number, and the second number (N2) of pole pairs is an even number.

4. An angular position sensor system (100; 300; 600; 1900; 2000) according to claim 2 or 3, wherein the processing circuit configured for determining :one of an additive combination of the magnetic field components measured by one pair of the first and the third magnetic sensor pair and the second and the fourth magnetic sensor pair for providing a first signal being indicative of an angular position of one of the first and second circular track with reduced cross-talk interference;a subtractive combination of the magnetic field components measured by the other pair of the first and the third magnetic sensors pair and the second and the fourth magnetic sensor pair for providing a second signal being indicative of an angular position of the other of the first and second circular track with reduced cross-talk interference;the absolute angular position (0) based on the first angular signal and on the second angular signal.

5. An angular position sensor system (100; 300; 600; 1900; 2000) according to any of the previous claims, wherein the processing circuit is configured for:e) determining a linear combination of two magnetic field components of the first magnetic field measured by one of the first and the second magnetic sensor (SI, S2) and by one of the third and fourth magnetic sensor (S3, S4);f) determining a linear combination of two magnetic field components of the second magnetic field measured by the other of the first and the second magnetic sensor (SI, S2) and by the other of the third and fourth magnetic sensor (S3, S4);g) determining said angular position (0) based on said linear combinations;preferably wherein each of said four sensors is configured for measuring two magnetic field components, and preferably wherein the processing circuit is configured for:e) determining a first linear combination and a second linear combination of two parallel magnetic field components (Bzl,Bz3; Byl, By3) measured by one of the first and the second magnetic sensor (SI, S2) and by one of the third and fourth magnetic sensor (S3, S4);60f) determining a third linear combination and a fourth linear combination of two parallel magnetic field components (Bz2,Bz4; By2,By4) measured by the other of the first and second magnetic field component and by the other of the third and fourth magnetic sensor (S2, S4);g) determining said angular position (9) based on the first, second, third and fourth linear combination.

6. An angular position sensor system (100; 300; 600; 1900; 2000) according to any of the previous claims, wherein each of said four sensors is configured for measuring two orthogonal magnetic field components, and wherein the processing circuit is configured for:e) determining a first sum (suml) and a second sum (sum2) of two parallel magnetic field components (Bzl,Bz3; Byl, By3) measured by one of the first and the second magnetic sensor (SI, S2) and by one of the third and the fourth magnetic sensor (S3, S4);f) determining a first difference (diffl) and a second difference (diff2) of two parallel magnetic field components (Bz2,Bz4; By2,By4) measured by the other of the first and second magnetic sensor (SI, S2) and by the other of the third and the fourth magnetic sensor (S3, S4);g) determining said angular position (9) based on the first and second sum (suml, sum2) and based on the first and second difference (diffl, diff2).

7. An angular position sensor system (100; 300; 600; 1900; 2000) according to claim 3 or 4, wherein the processing circuit is configured for deriving a first angle value (9M) from the first and the second linear combination or from the first and second sum (suml, sum2);and wherein the processing circuit is configured for deriving a second angle value (9N) from the third and fourth linear combination or from the first and the second difference (diffl, diff2);and wherein the processing circuit is configured for determining the angular position (9) based on the first and the second angle value (9M, 9N).

8. An angular position sensor system (100; 1900) according to any of the previous claims, wherein the magnetic source (110) comprises only two tracks (Tl, T2);wherein the first sensor (SI) and the third sensor (S3) are located in the vicinity of the first track (Tl), e.g. above the first track (Tl), preferably above a centreline (Cl) of the first track (Tl);and wherein the second sensor (S2) and the fourth sensor (S4) are located in the vicinity of the second track (T2), e.g. above the second track (T2), preferably above a centreline (C2) of the second track (T2).

9. An angular position sensor system (300; 600; 2000) according to any of the claims 1 to 7 ,61wherein the magnetic source (310; 610; 2010) further comprises the third track (T3) arranged such that the first track (Tl) is located between the second track (T2) and the third track (T3);preferably the magnetic poles of the second and the third track (T2, T3) being radially or axially aligned.

10. An angular position sensor system (300; 600; 2000) according to claim 9,wherein the first and the third sensor (SI, S3) are situated on the first track (Tl), the second sensor (S2) is situated on the second track (T2), and the fourth sensor (S4) is situated on the third track (T3);or wherein the second and the fourth sensor (S2, S4) are situated on the first track (Tl), the first sensor (SI) is situated on the second track (T2), and the third sensor (S3) is situated on the third track (T3).

11. An angular position sensor system (100; 300; 600; 1900; 2000) according to any of the previous claims,wherein the first and second magnetic sensor (SI, S2) are incorporated in a first packaged semiconductor device (221; 421; 621; 1921; 2021);and wherein the third and fourth magnetic sensor (S3, S4) are incorporated in a second packaged semiconductor device (222; 422; 622; 1922; 2022).

12. An angular position sensor system (100; 300; 600; 1900; 20900) according to any of the previous claims, wherein the first track (Tl) has a first track width wl in the range of 1.0 to 5.0 mm, preferably in the range of 2.0 to 4.0 mm.

13. An angular position sensor system (100; 300; 600; 1900; 2000) according to any of the previous claims,wherein each of the first, second, third and fourth sensor (SI, S2, S3, S4) comprises an integrated magnetic concentrator (IMC) disk and two horizontal Hall elements arranged near a periphery of the disk, angularly spaced by 180°;or wherein each of the first, second, third and fourth sensor comprises a horizontal Hall element and one vertical Hall element;or wherein each of the first, second, third and fourth sensor comprises a horizontal Hall element and two vertical Hall elements, arranged on opposite sides of the horizontal Hall element.

14. A sensor device (120; 220a; 220b; 320; 620) comprising:62- four magnetic sensors including a first, second, third and fourth magnetic sensor (SI, S2, S3, S4), situated at four different sensor locations (Pl, P2, P3, P4) situated on a virtual line (X), each magnetic sensor configured for measuring two orthogonal magnetic field components (Byl,Bzl; By2,Bz2; By3,Bz3; By4,Bz4);wherein a distance between the first and second sensor location (Pl, P2) is a value in the range from 1.0 to 3.0 mm, and a distance between the third and fourth sensor location (P3, P4) is a value in the range from 1.0 to 3.0 mm, and a distance between the first and the third sensor location (Pl, P3) is at least 25 mm;- a processing circuit configured for e) determining a first sum (suml) and a second sum (sum2) of two parallel magnetic field components (Bzl,Bz3; Byl, By3) measured by the first and the third magnetic sensor (SI, S3),and for f) determining a first difference (diffl) and a second difference (diff2) of two parallel magnetic field components (Bz2,Bz4; By2,By4) measured by the second and the fourth magnetic sensor (S2, S4);and for g) determining and angular position (9) based on the first and second sum (suml, sum2) and based on the first and second difference (diffl, diff2).

15. An angular position sensor system (100; 300; 600; 1900; 2000) comprising:a magnetic source (110; 310; 610; 1910; 2010) rotatable about a rotation axis, the magnetic source comprising : a first circular track having a first number of magnetic pole pairs for generating a first magnetic field having a first periodicity, and a second circular track having a second number of magnetic pole pairs for generating a second magnetic field having a second periodicity; wherein a quotient of the first number divided by a greatest common divisor of the first and the second number ( N2) is an even number, and a second quotient of the second number divided by said greatest common divisor is an odd number;- a sensor device movable relative to the magnetic source, or vice versa; wherein the sensor device comprises a first magnetic sensor located at a first sensor location and a second magnetic sensor located at a second sensor location, each magnetic sensor configured for measuring at least one but preferably two magnetic field components oriented in different directions; wherein the first and the second sensor location are angularly spaced by a predefined angle with respect to the rotation axis around or above the magnetic source; the predefined angle corresponding to an odd multiple of a straight angle divided by the greatest common divisor of the first and the second number of magnetic pole pairs; and- a processing circuit configured for determining an absolute angular position (9) of the magnetic source relative to the sensor device based on :an additive combination of the magnetic field components measured by the first and the second magnetic sensor for providing a first signal being indicative of a first angular position of the magnetic source, preferably of the first circular track, and ona subtractive combination of the magnetic field components measured by the first and the second magnetic sensor for providing a second signal being indicative of a second angular position of the magnetic source, preferably of the second circular track.

16. A method (1400) of determining an angular position of a magnetic source (110; 310; 610; 1910; 2010) relative to a sensor device (120; 320; 620),wherein the sensor device comprises a first, second, third and fourth magnetic sensor (e.g. SI, S2, S3, S4) located at four sensor locations (e.g. Pl, P2, P3, P4);wherein the magnetic source is rotatable about a rotation axis and comprises at least two circular tracks (T1,T2; T1,T2,T3) including a first circular track (Tl) having a first number (Ml) of magnetic pole pairs for generating a first magnetic field having a first periodicity, and a second circular track (T2) and optionally also a third circular track (T3) having a second number (N2) of magnetic pole pairs for generating a second magnetic field having a second periodicity;wherein a first quotient of the first number divided by a greatest common divisor of the first and the second number (M1,N2) is an even number, and a second quotient of the second number divided by said greatest common divisor is an odd number, or vice versa;the method comprising the steps of:a) measuring (1403) by the sensor device at least one magnetic field component of the first magnetic field at two positions around the rotation axis, one angularly spaced from the other by a first angle with respect to the rotation axis;c) measuring (1405) by the sensor device at least one magnetic field component of the second magnetic field at two positions around the rotation axis, one angularly spaced from the other by a second angle with respect to the rotation axis;g) determining (1409) an angular position (9) based on the measured magnetic field components.

17. A method (1400) according to the claim 16, each of said first and second angle being substantially equal to a product of an odd integer number multiplied by 180° and divided by the greatest common divisor.

18. A method (1400) according to the claim 16 or 17, wherein step g) comprises:- combining said measured magnetic field components of the first magnetic field at said two positions to produce a first track signal; and- combining said measured magnetic field components of the second magnetic field at said two positions to produce a second track signal; and- determining said angular position (9) based on said first and second track signal.

19. A method (1400) according to any one of the claims 16 to 18,wherein said combining said measured magnetic field components of the first magnetic field comprises: additive or subtractive combining the magnetic field components measured by one pair of the first and the third magnetic sensor pair and the second and the fourth magnetic sensor pair for providing a first track signal indicative of an angular position of the first circular track with reduced crosstalk interference; andwherein said combining said measured magnetic field components of the second magnetic field comprises: additive or subtractive combining the magnetic field components measured by the other pair of the first and the third magnetic sensor pair and the second and the fourth magnetic sensor pair for providing a second track signal indicative of an angular position of the second and / or third circular track with reduced cross-talk interference.

20. A method (1400) according to any of the claims 16 to 19, wherein the first and the second number (Ml, N2) are co-prime numbers, preferably one even number and one odd number.

21. A method (1400) according to any of the claims 16 to 20,wherein the magnetic source is rotatable about a rotation axis and comprises at least two circular tracks including a first circular track (Tl) having a first number (Ml) of magnetic pole pairs for generating a first magnetic field having a first periodicity, and a second circular track (T2) and optionally also a third circular track (T3) having a second number (N2) of magnetic pole pairs for generating a second magnetic field having a second periodicity, the first and second number (Ml, N2) being co-prime numbers, preferably one even number and one odd number;the method comprising the steps of:a) measuring (1403) by the first and the second magnetic sensor (SI, S2) at least one magnetic field component of the first magnetic field at one of said first and second sensor location (P1,P2), and measuring at least one magnetic field component of the second magnetic field at the other of said first and second sensor location (Pl, P2);c) measuring (1405) by the third and the fourth magnetic sensor (S3, S4) at least one magnetic field component of the first magnetic field at one of said third and fourth sensor location (P3, P4), and measuring at least one magnetic field component of the second magnetic field at the other of said third and fourth sensor location (P3, P4);65g) determining (1409) an angular position (9) based on the measured magnetic field components.

22. A method according to any of the claims 16 to 21, wherein two magnetic field components are measured at each of said four sensor locations (Pl, P2, P3, P4);and wherein the method further comprises the following steps:e) determining (1407; 1507; 1607) a first and a second linear combination for each pair of parallel magnetic field components measured by the first and third magnetic sensor (SI, S3);f) determining (1408; 1508; 1608) a third and a fourth linear combination for each pair of parallel magnetic field components measured by the second and fourth magnetic sensor (S2, S4); and wherein step g) comprises:g) determining (1409; 1509; 1609) said angular position (9) based on the first, second, third and fourth linear combination.

23. A method according to any of the claims 16 to 22, wherein two orthogonal magnetic field components are measured at each of said four sensor locations (Pl, P2, P3, P4);further comprising the following steps:e) determining (1407; 1507; 1607) a first and a second sum (suml, sum2) for each pair of parallel magnetic field components measured by the first and third magnetic sensor (SI, S3);f) determining (1408; 1508; 1608) a first and a second difference (diffl, diff2) for each pair of parallel magnetic field components measured by the second and fourth magnetic sensor (S2, S4); and wherein step g) comprises:g) determining (1409; 1509; 1609) said angular position (9) based on the first and second sum (suml, sum2) and based on the first and second difference (diffl, diff2).

24. A magnetic source (2010; 2110) comprising three circular tracks (Tl, T2, T3) including a first track (Tl), a second track (T2) and a third track (T3);wherein the first track (Tl) is located between the second track (T2) and the third track (T3); wherein the first track (Tl) has a first number (Ml) of magnetic pole pairs;wherein each of the second and third track (T2, T3) has a second number (N 2) of magnetic pole pairs;wherein the magnetic poles of the second and the third track (T2, T3) are radially aligned or axially aligned;wherein a greatest common divisor of the first and the second number (Ml, N2) is 1; preferably one of the first number (Ml) and the second number (N2) is an even number, and the other of the first number and the second number (N2) is an odd number.

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