Apparatus and system for determining the position of a magnetic source or the orientation of a uniform magnetic field - Patents.com

Abstract

To provide a sensor device that can determine a position of a magnetic source, or orientation of a substantially uniform magnetic field.SOLUTION: A sensor device (1202) comprises: a substrate that is equipped with a plurality of magnetic sensors (H1, H2, H3 and H4) configured to provide a plurality of sensor signals (h1, h2, h3 and h4); a signal combiner (MUX,Σ) that is configured to combine the sensor signal into a combined waveform; and a processing circuit that is configured to extract a position or orientation from the combined waveform, in which the signal combiner is configured to generate the combined waveform by including one or more portions of the sensor signals during respective prescribed time durations (Δ t 11 to Δ t 44). The time durations (Δ t 11 to Δ t 44) are determined during a calibration procedure, and at least two of the time durations (Δ t 11 to Δ t 44) have different values.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates generally to the field of magnetic sensor systems, and more particularly to magnetic position sensor systems and devices for determining the linear or angular position of a sensor device relative to a magnetic source, or a magnetic sensor device for determining the orientation of a substantially uniform magnetic field relative to said magnetic sensor device. [Background technology]

[0002] Magnetic position sensor systems, particularly linear or angular position sensor systems, are known in the art. Many of these systems rely on the measurement of sine and cosine signals and use the arctangent function to calculate the angle.

[0003] However, in reality, magnetic sensors are not perfect, nor are the magnets used in such systems. Magnetic sensors may have, for example, offsets, gain mismatches, position errors, orientation errors. Magnets may have, for example, geometric deviations, material imperfections, mounting imperfections (e.g., position offsets or tilts), and therefore the magnetic fields generated by such magnets are not ideal.

[0004] US8963540 (B2) describes an angular orientation sensor based on the Hall effect, as well as corresponding methods and devices. The sensor device includes a number of Hall sensors and an interconnect unit W that combines the Hall voltages from the multiple sensors to output a step-wave signal that approximates a sine wave. The sensor device further includes a band-pass filter BPF and a phase detection unit. DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0005] It is an object of embodiments of the present invention to provide a sensor device capable of determining the position (e.g. linear or angular position) of a magnetic source that is movable relative to the sensor device or vice versa, or capable of determining the orientation of a substantially uniform magnetic field (e.g. the Earth's magnetic field, or a magnetic field generated by at least one coil).

[0006] It is also an object of an embodiment of the present invention to provide a sensor system comprising such a sensor device and a magnetic source, for example in the form of a permanent magnet or an elongated structure having a number of alternating poles.

[0007] It is an aim of embodiments of the present invention to provide such a sensor device and sensor system that provides position with improved accuracy despite imperfections in the sensor and / or magnetic source.

[0008] It is an object of embodiments of the present invention to provide such sensor devices and sensor systems that are capable of determining said position or orientation at a relatively high rate, for example at least 20 kHz, or at least 100 kHz, or at least 500 kHz, or at least 1 MHz, or at least 2 MHz, or at least 4 MHz, or at least 8 MHz.

[0009] It is an object of an embodiment of the present invention to provide an angular position sensor system for measuring the angular position of a magnet rotating at speeds up to 5000 RPM, or up to 10000 RPM, with an absolute error of less than 5°, or less than 4°, or less than 3°, or less than 2°, or less than 1°, or less than 0.5°, or less than 0.3°.

[0010] It is an object of embodiments of the present invention to provide an angular position sensor device and system, where the device includes multiple Hall elements, but the Hall elements are not trimmed (e.g., to compensate for sensitivity mismatch (or mismatch), or other sensor imperfections such as offset, or geometric imperfections such as non-orthogonality).

[0011] It is an aim of embodiments of the present invention to provide such a sensor device and sensor system which has reduced sensitivity to disturbance fields. [Means for solving the problem]

[0012] These and other objects are achieved by embodiments of the present invention.

[0013] According to a first aspect, the present invention provides a sensor device for determining the position (e.g. linear or angular) of a magnetic source that is movable relative to the sensor device or vice versa, or for determining the orientation of a substantially uniform magnetic field (e.g. the Earth's magnetic field), the sensor device comprising a substrate comprising a plurality of at least two magnetic sensors configured to provide a plurality of at least two sensor signals, a signal combiner (or signal combiner) configured to combine the sensor signals into a (e.g. single) composite waveform, and a processing circuit configured to extract said position or orientation from the composite waveform, the signal combiner being configured to generate the composite waveform by including one or more portions of the sensor signals for respective predetermined durations, the predetermined durations being determined during a calibration procedure, and at least two of said predetermined durations having different values.

[0014] The goal of the calibration procedure is to find some (or several) durations that reduce the overall position or orientation error. Note that there may be several sets of durations that reduce the overall position or orientation error (see, for example, the three solutions proposed in Figures 12, 13, and 14).

[0015] Calibration can be performed at the chip level (without a magnetic source) using a constant magnetic field (e.g., generated by a coil). These calibration values ​​reduce or eliminate errors typically associated with sensor sensitivity mismatch and non-ideal positioning of the sensor elements.

[0016] By "substantially uniform magnetic field orientation" is meant, for example, the orientation of the Earth's magnetic field in an E-compass application, or the orientation of the magnetic field generated by a coil.

[0017] The calibration values ​​may be stored in non-volatile memory (eg, flash) connected to or embedded in the sensor device.

[0018] The substrate may be a semiconductor substrate.

[0019] The sensor device may be contained in a package also called a "chip", although this is not absolutely necessary.

[0020] In one embodiment, the processing circuitry comprises a bandpass filter and a phase detector.

[0021] Phase detection may be based on detecting zero crossings of the bandpass filtered signal, for example using a counter and a comparator, or in other known ways.

[0022] In one embodiment, a signal combiner is configured to generate the composite waveform according to a timing scheme having a predetermined duration Ts, the predetermined duration Ts being divided into a number of timing windows each having a duration of Ts / N, where N is the number of sensors.

[0023] The predetermined time duration Ts is the inverse of the sampling frequency fs at which the (e.g., linear or angular) position or orientation is provided. The value of fs may be in the range of 20 kHz to 20 MHz, or 50 kHz to 15 MHz, or 100 kHz to 10 MHz, for example equal to about 1.0 MHz, or equal to about 16.0 MHz.

[0024] The counter of the phase detector may operate at a clock frequency fc at least 100 times faster than the sampling frequency fs.

[0025] The signal combiner (eg, a multiplexer or a switch) may be operated at a clock frequency at least 100 times faster than the sampling frequency fs.

[0026] Preferably, the duration of said portions (eg Δt11 to Δt44) is less than 90% of the duration of the timing window, or less than 80% of the duration of the timing window, or less than 70% of the duration of the timing window.

[0027] In one embodiment, the signal combiner is configured to include only one portion of the sensor signal in each timing window.

[0028] An example of this embodiment is shown in Figure 12. For example, a first timing window w1 includes a portion of a first sensor signal h1 having duration Δt11, a second time window w2 includes a portion of a second sensor signal h2 having duration Δt22, and so on.

[0029] Preferably, these portions are located near the center of the timing window (also known as "centrally aligned") to reduce jitter.

[0030] This embodiment offers the advantage that its implementation is relatively simple, since no additional signals need to be added to the timing window.

[0031] In one embodiment, the number of sensors is even, the sensors are equidistantly spaced on an imaginary circle, and the signal combiner is configured to add or subtract portions of two diametrically opposed sensors in each timing window.

[0032] An example of this embodiment is shown in Figure 13. For example, assuming a sensor device has four sensor elements, with sensors H1 and H3 positioned diametrically opposite one another and sensors H2 and H4 positioned diametrically opposite one another, a waveform of this embodiment is generated such that in a first timing window w1, a portion of the first sensor signal h1 (having width Δt11) and a portion of the third sensor signal h3 (having width Δt13) are added, and in a second time window w2, a portion of the second sensor signal h2 (having width Δt22) and a portion of the fourth sensor signal h4 (having width Δt24) are added.

[0033] Again, it is preferable for all portions to be located near the center of the timing window to reduce jitter.

[0034] This embodiment offers the additional advantage that the position or orientation so determined is highly insensitive to disturbance fields.

[0035] In one embodiment, the signal combiner is configured to add or subtract only two portions of the sensor signals originating from two diametrically opposed sensors in each timing window.

[0036] In one embodiment, the signal combiner is configured to add or subtract portions of at least two, or at least three, or at least four sensor signals in each timing window.

[0037] For example, as shown in FIG. 14, a first timing window w1 may have a portion of a first sensor signal h1 having duration Δt11, add to it a portion of a third sensor signal h3 having duration Δt13, add to it a portion of a second sensor signal h2 having duration Δt12, and add to it a portion of a fourth sensor signal h4 having duration Δt14 (not visible in FIG. 14).

[0038] Again, it is preferable for all portions to be located near the center of the timing window to reduce jitter.

[0039] In one embodiment, the signal combiner is configured to add or subtract a portion of each sensor signal in each timing window, with each portion having a predetermined duration.

[0040] In this embodiment, the number of portions summed in each time window is equal to the number of sensors over the respective duration. If the parameters are well chosen, this embodiment results in the lowest position or orientation error and therefore provides the highest accuracy.

[0041] In one embodiment, the durations of at least two or at least three portions to be added or subtracted have different values ​​from each other.

[0042] For instance, in the example in Figure 13, at least one of the following statements is true: Δt11<>Δt13; Δt22<>Δt24; Δt31<>Δt33; Δt42<>Δt44.

[0043] In one embodiment, the magnetic source (101) is a permanent magnet rotatable about an axis of rotation, and the position determined is the angular position (φ).

[0044] Preferably, the magnetic source is a two-pole permanent magnet, for example a two-pole bar magnet, or a two-pole disk magnet, or a two-pole ring magnet.

[0045] In one embodiment, the magnetic source is an elongated structure having one pole pair or having multiple alternating poles, the sensor device is movable relative to the magnetic structure a fixed distance (also known as an "air gap"), and the position that is determined is a linear position (e.g., x) along the elongated structure.

[0046] In one embodiment, the substantially uniform magnetic field is the Earth's magnetic field or a magnetic field generated by at least one coil, and the orientation determined is an angle (φ) relative to a reference orientation.

[0047] Such a sensor device may be used in an E-compass.

[0048] In one embodiment, some or all of the sensors are configured to measure the magnetic field in a direction perpendicular to the substrate (eg, Bz).

[0049] In one embodiment, some or all of the sensors are configured to measure magnetic fields (eg, Bx, By, Br, Bt) in a direction parallel to the substrate.

[0050] In one embodiment, a first subset of sensors is configured to measure a magnetic field in a direction perpendicular to the substrate (e.g., Bz), and a second subset of sensors is configured to measure a magnetic field in a direction parallel to the substrate (e.g., Bx, By, Br, Bt).

[0051] In one embodiment, some or all of the sensors are configured to measure a radial magnetic field (eg, Br) parallel to the substrate.

[0052] In one embodiment, some or all of the sensors are configured to measure the magnetic field (eg, Bt) in a circumferential direction parallel to the substrate.

[0053] The magnetic field components parallel to the substrate may be denoted as Bx (X-direction) or By (Y-direction), or Br (radially oriented), or Bt (circumferentially oriented, ie tangential to an imaginary circle).

[0054] In one embodiment, some or all of the sensors are horizontal Hall elements.

[0055] In one embodiment, some or all of the sensors are vertical Hall elements and have their axis of maximum sensitivity circumferentially oriented or have their axis of maximum sensitivity oriented radially.

[0056] In one embodiment, some or all of the sensors are magnetoresistive elements and have their axis of maximum sensitivity oriented circumferentially, or alternatively have their axis of maximum sensitivity oriented radially.

[0057] In one embodiment, the sensor is configured to measure magnetic fields in at least two different orientations.

[0058] The sensor can have, for example, four vertical Hall elements, two of the sensors oriented to have their axes of greatest sensitivity in the X direction and the other two sensors oriented to have their axes of greatest sensitivity in the Y direction, where X and Y are orthogonal axes parallel to the substrate, as shown, for example, in FIG. 7.

[0059] As another example, the sensor device may have only two sensors, one vertical Hall element to measure Bx and one vertical Hall element to measure By (e.g., a variation of FIG. 7 having only V1 and V2).

[0060] In one embodiment, the sensor elements are located on an imaginary circle.

[0061] In one embodiment, the sensor elements are located on an imaginary circle and are equidistantly spaced apart.

[0062] According to a second aspect, the present invention also provides a position sensor system comprising a sensor device according to the first aspect and said magnetic source.

[0063] In one embodiment, the predetermined time durations (eg, Δt11 through Δt44) are determined during a calibration procedure performed using a test setup that includes the sensor device and a magnetic source.

[0064] These calibration values ​​not only reduce errors typically associated with sensor sensitivity mismatch, but also correct for non-idealities in the magnetic source.

[0065] The invention is defined by the independent claims. The dependent claims define advantageous embodiments.

[0066] These and other features and advantages of the present invention will become apparent from the following description of non-limiting embodiments of the invention, which are illustrated below with reference to the drawings. [Brief description of the drawings]

[0067] [Figure 1] 1 is a schematic diagram of an angular position sensor system comprising a permanent magnet and a sensor device. The magnet is rotatable about an axis of rotation. The sensor device is positioned "on-axis." [Diagram 2] 2 is a schematic diagram of an angular position sensor system comprising a permanent magnet and a sensor device. The magnet is rotatable about an axis of rotation. The sensor device is placed "off-axis", for example next to the magnet or below the magnet. [Diagram 3] FIG. 3 shows a substrate having four horizontal Hall elements arranged on an imaginary circle spaced apart by multiples of 90° as may be used in embodiments of the present invention. [Figure 4] FIG. 4 shows a substrate having six horizontal Hall elements arranged on an imaginary circle spaced apart by multiples of 60° as may be used in embodiments of the present invention. [Diagram 5]FIG. 5 shows a substrate having four vertical Hall elements arranged on an imaginary circle, spaced apart by multiples of 90° and oriented with their axes of greatest sensitivity in the radial direction, as may be used in embodiments of the present invention. [Figure 6] FIG. 6 shows a substrate having six vertical Hall elements arranged on an imaginary circle, spaced apart by multiples of 60° and oriented with their axes of greatest sensitivity in the radial direction, as may be used in embodiments of the present invention. [Figure 7] FIG. 7 shows a substrate having four vertical Hall elements arranged on an imaginary circle, spaced apart by multiples of 90° and oriented with their axis of greatest sensitivity in the circumferential direction, as may be used in embodiments of the present invention. [Figure 8] FIG. 8 shows a substrate having six vertical Hall elements arranged on an imaginary circle, spaced apart by multiples of 60° and oriented with their axis of greatest sensitivity in the circumferential direction, as may be used in embodiments of the present invention. [Figure 9] FIG. 9 illustrates a high level block diagram of a sensor device according to an embodiment of the present invention. [Figure 10] FIG. 10 illustrates a high level block diagram of a sensor device according to an embodiment of the present invention. [Figure 11] FIG. 11 illustrates a high level block diagram of a sensor device according to an embodiment of the present invention. [Figure 12] FIG. 12 shows a more detailed schematic block diagram of a sensor device according to an embodiment of the present invention. [Figure 13] FIG. 13 shows a more detailed schematic block diagram of a sensor device according to an embodiment of the present invention. [Figure 14] FIG. 14 shows a more detailed schematic block diagram of a sensor device according to an embodiment of the present invention.

[0068] The drawings are only schematic and non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes.

[0069] In the various figures, elements which are equivalent in terms of their functionality are usually given the same reference numbers / signs modulo 100 and therefore these elements will usually only be described once. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0070] 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.

[0071] It should be noted that the individual features recited in the following description can be combined with each other in any manner that is technically meaningful (and across different categories, e.g., devices and methods) to represent further embodiments of the present invention. The description of the present invention will be further characterized and specified, particularly in conjunction with the figures.

[0072] Furthermore, it should be understood that the term "and / or" or the phrase "at least one of" or "one or more of," when used herein to combine a first and a second feature, should be interpreted as disclosing a first embodiment of the invention comprising only the first feature, a second embodiment of the invention comprising only the second feature, and a third embodiment of the invention comprising both the first and second features. When more than two features are recited, any combination thereof should also be interpreted as a disclosed embodiment according to the invention.

[0073] Furthermore, the terms "approximately" or "essentially" or "substantially" indicate a tolerance that would be considered normal by a person skilled in the art. In particular, the terms "approximately" or "essentially" or "substantially" should be understood as a tolerance of the amount referred to of up to ±20%, preferably up to ±10%.

[0074] As used herein, the terms "sensor" or "magnetic sensor" may refer to a component or group of components or sub-circuits or structures that can measure a magnetic quantity, such as, for example, a magnetoresistive element, a GMR element, an XMR element, a horizontal Hall plate, a vertical Hall plate, a Wheatstone bridge including at least one magnetoresistive element, or an inductive transducer (e.g., a receiving coil of an inductive magnetic sensor).

[0075] Embodiments of the present invention are typically described using a Cartesian coordinate system having three axes X, Y, Z, fixed to the sensor device, where the X and Y axes are parallel to the substrate (e.g., a semiconductor substrate) and the Z axis is perpendicular to the substrate.

[0076] In this specification, horizontal Hall plates are typically referred to as H1, H2, etc., and the signals obtained from these horizontal Hall plates are typically referred to as h1, h2, etc., and vertical Hall plates are typically referred to as V1, V2, etc., and the signals obtained from these vertical Hall plates are typically referred to as v1, v2, etc.

[0077] The present invention relates to a magnetic position sensor system, in particular to a linear or angular position sensor system comprising a magnetic source and a magnetic position sensor device. The magnetic source can be for example a two-pole disk magnet, or a two-pole ring magnet, or a two-pole bar magnet, or an elongated or circular magnetic structure comprising multiple alternating poles. The present invention also relates to such a magnetic position sensor device itself. However, it is noted that the present invention also works with magnets having at least four poles, or at least six poles, etc.

[0078] Please refer to the figure.

[0079] 1 and 2 show some illustrative examples of angular position sensor systems in which the techniques proposed by the present invention may be applied, but the present invention is not limited thereto and the techniques described further may also be applied, for example, to linear position sensor systems (not explicitly shown). Such linear position sensor systems may, for example, comprise a two-pole bar magnet, or an elongated magnetic structure with at least four alternating magnetic poles. The present invention also relates to a magnetic sensor device configured to determine the orientation of a substantially uniform magnetic field (e.g., the Earth's magnetic field), or a magnetic field generated by at least one coil, such as may be used in an electronic compass (eCompass).

[0080] 1 is a schematic diagram of an angular position sensor system 100 comprising a magnet 101 and a sensor device 102. The magnet 101 is rotatable about an axis of rotation. The sensor device 102 is positioned "on-axis".

[0081] 2 is a schematic diagram showing two angular position sensor systems with sensor devices located "off-axis". The first angular position sensor system comprises a magnet 201 and a sensor device 202a located below the magnet. The second angular position sensor system comprises a magnet 201 and a sensor device 202b located next to the magnet (also called "equatorial" or "satellite position").

[0082] Although Figures 3-8 show some illustrative examples of sensor arrangements that may be used in embodiments of the present invention, the invention is not so limited and other sensor arrangements may be used.

[0083] FIG. 3 shows a substrate with four horizontal Hall elements H1-H4 arranged on an imaginary circle spaced apart by multiples of 90°. The substrate is not explicitly shown. The horizontal Hall elements may be integrated into or mounted on said substrate. In a preferred embodiment of the invention, the substrate is a silicon substrate and the sensors are embedded therein. This also applies to FIGS. 4 to 8.

[0084] FIG. 4 shows a substrate having six horizontal Hall elements H1-H6 arranged on an imaginary circle spaced apart by multiples of 60°.

[0085] Although not explicitly shown, it is also possible to use a substrate having eight horizontal Hall elements arranged on an imaginary circle and spaced apart by multiples of 45°, although substrates having more than eight horizontal Hall elements are also possible, e.g. ten Hall elements spaced apart by multiples of 36°, or twelve Hall elements spaced apart by multiples of 30°.

[0086] FIG. 5 shows a substrate in which four vertical Hall elements V1-V4 are arranged on an imaginary circle, spaced apart by multiples of 90°, and oriented with their axis of maximum sensitivity in the radial direction.

[0087] FIG. 6 shows a substrate with six vertical Hall elements V1-V6 arranged on an imaginary circle, spaced apart by multiples of 60° and oriented with their axis of maximum sensitivity in the radial direction.

[0088] Although not explicitly shown, it is also possible to use a substrate having eight vertical Hall elements arranged on an imaginary circle, spaced apart by multiples of 45° and oriented with their axis of maximum sensitivity in the radial direction, although substrates having more than eight vertical Hall elements are also possible, e.g. ten Hall elements spaced apart by multiples of 36°, or twelve Hall elements spaced apart by multiples of 30°.

[0089] FIG. 7 shows a substrate in which four vertical Hall elements V1-V4 are arranged on an imaginary circle, spaced apart by multiples of 90° and oriented with their axis of maximum sensitivity in the circumferential direction, i.e., tangential to the imaginary circle.

[0090] FIG. 8 shows a substrate with six vertical Hall elements V1-V6 arranged on an imaginary circle, spaced apart by multiples of 60° and oriented with their axis of maximum sensitivity in the circumferential direction.

[0091] Although not explicitly shown, it is also possible to use a substrate having eight vertical Hall elements arranged on an imaginary circle, spaced apart by multiples of 45° and oriented with their axis of greatest sensitivity in the circumferential direction, although substrates having more than eight vertical Hall elements are also possible, for example ten Hall elements spaced apart by multiples of 36°, or twelve Hall elements spaced apart by multiples of 30°.

[0092] In the examples shown in Figures 3-8, the sensors are arranged on an imaginary circle and are equally spaced, although this is preferred, but not necessary for the invention to work. Indeed, the invention will work if the sensors are not equidistantly spaced. In fact, the sensors need not be arranged on a single circle, but the invention will also work if the sensors are arranged on two imaginary circles, or at the intersections of a regular grid, or pseudo-randomly.

[0093] In the examples shown in Figures 3 to 8 the sensors are horizontal or vertical Hall elements, however the invention is not limited to this and will also work with other sensor technologies, for example magnetoresistive elements such as xMR, TMR, AMR, GMR or inductive sensors.

[0094] It should be noted that the principles of the present invention also work with sensor configurations including only two sensors, such as, for example, in the variant of FIG. 3 including only two horizontal Hall elements H1 and H2, or in the variant of FIG. 5 including only two vertical Hall elements V1 and V2 with their axes of greatest sensitivity oriented radially, or in the variant of FIG. 7 including only two vertical Hall elements V1 and V2 with their axes of greatest sensitivity oriented circumferentially.

[0095] However, as will be further appreciated, it may be advantageous to use more than two sensors, for example four sensors, or five sensors, or six sensors, or seven sensors, or eight sensors, since the techniques used in embodiments of the present invention may utilize redundancy to increase accuracy and may also be used for error detection.

[0096] For ease of explanation, the present invention will be further described using the sensor device of FIG. 3, but as already mentioned, the present invention is not limited thereto. The present invention can be considered as an alternative or improvement to the apparatus and system described in patent document US8963540(B2), the entirety of which is incorporated herein by reference. Reading this document may be helpful to better understand and appreciate the present invention.

[0097] 9 shows a high-level block-diagram of a sensor device 902 proposed by the present invention. The sensor device 902 comprises a sensor device 905, a “biasing and readout circuit” 910, and a signal processing circuit 920.

[0098] As already mentioned above, several sensor configurations may be used, such as any of the examples shown in Figures 3 to 8, but other sensor configurations comprising at least two sensors oriented in different directions may also be used.

[0099] "Bias and readout" circuits are well known in the art, but are not the primary focus of the present invention, and therefore need not be described in greater detail herein. Suffice it to say that Hall elements and Wheatstone bridges, comprising one or more magnetoresistance elements, are electrical devices having two "excitation nodes" and two "output nodes". They can be biased by applying a known voltage or a known current to the "excitation nodes", and the sensor signal can be obtained as a differential voltage signal across the "output nodes". The bias and readout circuit 910 also typically comprises an amplifier (not explicitly shown) for amplifying the sensor signal. For ease of explanation, it is assumed that the output of the amplifier is a "single-ended" voltage signal (i.e., referenced to ground).

[0100] The "signal processing circuit" 920 is the main contribution of the present invention over the prior art and will be described in more detail. Importantly, most of the signal processing in the sensor device 902 is performed in the analog domain, using time-continuous signals. This offers the advantages that the processing can be very fast without the need for a high-speed digital signal processor (DSP), analog-to-digital converters (DACs) are not absolutely necessary, and quantization errors can be avoided.

[0101] Figure 9 shows a general block diagram. Figure 10 shows a special case of Figure 9, where the signal processing circuit 1020 includes a multiplexer (e.g., an analog N-to-1 multiplexer), a bandpass filter, and a phase detector. A more detailed example is described in Figure 12.

[0102] Figure 11 shows another special case of Figure 9, where the signal processing circuit 1120 includes a number of switches, a signal combiner (e.g., for adding or subtracting signals), a bandpass filter, and a phase detector. More detailed examples are discussed in Figures 13 and 14.

[0103] 12 shows a schematic block diagram of a sensor device proposed by the present invention. The sensor device 1202 comprises a “sensor arrangement” 1205, a “bias and readout circuit” (not explicitly shown) and a signal processing circuit 1220.

[0104] In the example shown in Figure 12, a sensor device 1205 comprises four horizontal Hall sensors H1-H4 configured as shown in Figure 3. Ideally, the four sensors H1-H4 are arranged on an imaginary circle, have exactly the same layout, are spaced apart by multiples of 90°, and if they are brought into close proximity to a two-pole magnet (e.g., as shown in Figure 1 or Figure 2), the four signals can be described as sinusoidal signals that are phase shifted by 90° with respect to each other.

[0105] However, in practice, the four sensors H1-H4 typically have a sensitivity mismatch (or gain mismatch), i.e. the amplitudes of the four signals are not the same and optionally also have an offset, i.e. the output of the sensor element is not zero even in the absence of a magnetic field. Such imperfections may be measured, for example, during a calibration test of the device, in a test environment where a known magnetic field is applied. The results of such measurements may, for example, result in the values ​​listed in the table below. TIFF0007628590000001.tif41169

[0106] While in the prior art gain and offset mismatches are typically "addressed" by laser trimming, this is not absolutely necessary in the present invention, and therefore the signals h1, h2, h3, h4 obtained from the sensors may have slightly different gains and / or non-zero offsets.

[0107] The signal processing circuit 1220 comprises a multiplexer MUX, in this example a 4 to 1 analog multiplexer, acting as a signal combiner configured to combine portions of the sensor signals h1, h2, h3, h4 into a single composite waveform.

[0108] More specifically, the multiplexer MUX is configured to generate waveforms according to a timing scheme having a predetermined duration Ts (e.g. having a value of approximately 4 μs), which is divided into a number of timing windows w1, w2, w3, w4 each having a duration of Ts / 4 when the four sensors are equally spaced, such that in this example each window has a duration of approximately 1 μs.

[0109] Other values ​​of the predetermined duration Ts can also be used, for example 1 / fs (where fs=20 kHz, or fs=40 kHz, or fs=80 kHz, or fs=200 kHz, or fs=400 kHz, or fs=800 kHz).

[0110] The multiplexer MUX is configured to include a portion of the first sensor signal h1 during a first predetermined duration Δt11 in the first time window w1, a portion of the second sensor signal h2 during a second predetermined duration Δt22 in the second time window w2, a portion of the third sensor signal h3 during a third predetermined duration Δt33 in the third time window w3, and a portion of the fourth sensor signal h4 during a fourth predetermined duration Δt44 in the fourth time window w4 (or the multiplexer MUX is configured to include a portion of the first sensor signal h1 during a first predetermined duration Δt11 in the first time window w1, a portion of the second sensor signal h2 during a second predetermined duration Δt22 in the second time window w2, a portion of the third sensor signal h3 during a third predetermined duration Δt33 in the third time window w3, and a portion of the fourth sensor signal h4 during a fourth predetermined duration Δt44 in the fourth time window w4). Preferably, to reduce or avoid jitter, the portions are aligned to the centre of (or centred within) each time window w1-w4.

[0111] The processing circuit 1220 further comprises a bandpass filter BPF configured to pass primarily the fundamental harmonic of the waveform generated by the multiplexer MUX and to remove higher harmonics. Bandpass filters are well known in the art and therefore need not be described in greater detail herein.

[0112] The output of the bandpass filter is fed to a phase detector configured to detect the phase φ of the signal. The phase detector may be identical to that described in US8963540(B2), but the invention is not limited thereto and any other suitable phase detector may be used. The phase detection may be based on detecting zero crossings of the bandpass filtered signal. The instants of zero crossings may be measured using a counter.

[0113] The main difference between the circuit of FIG. 12 of the present invention and the circuit described in US8963540(B2) is that instead of filling the first time window w1 completely with the first sensor signal h1, filling the second time window w2 completely with the second sensor signal h2, etc., in the present invention the time windows w1-w4 are only partially filled with sensor signals. More specifically, in the first time window w1 only a portion of h1 is used for a predefined period Δt11, in the second time window w only a portion of h2 is used for a second predefined period Δt22, etc. Typically the values ​​of Δt11, Δt22, Δt33 and Δt44 are four different values, although some of the values ​​may be consistent and equal. The values ​​of the periods Δt11, Δt22, Δt33 and Δt44 are preferably determined during a calibration procedure, aiming to maximize the overall accuracy or minimize the overall error.

[0114] Without going into detail here, it can simply be stated that the values ​​of the predetermined durations Δt11, Δt22, Δt33, Δt44 are selected such that the resulting phase or angle φ has good accuracy despite the above-mentioned gain mismatch and non-zero offset.

[0115] As a rule of thumb (and as an initial set of values ​​during the calibration procedure), the periods Δt11, Δt22, Δt33, Δt44 may be selected inversely proportional to the respective gains of the sensors H1 to H4. As will be explained further, more suitable periods may be found during the calibration procedure. In fact, the "best value" may also compensate for some non-idealities of the magnetic sources, e.g. material imperfections, mounting offsets, tilts, etc.

[0116] In practice, at least two of the values ​​Δt11, Δt22, Δt33, and Δt44 will differ from each other, but more often, all of these values ​​will differ from each other. Note that it is the relative durations that are important, not the absolute values ​​of the durations. In one embodiment, the absolute values ​​of Δt11, Δt22, Δt33, and Δt44 may be selected to be approximately 30% to 70% of the durations of the time windows w1 to w4.

[0117] The processing circuit 1220 may further comprise a clock circuit, typically connected to an (external) crystal oscillator.

[0118] The processing circuit 1220 may further comprise control logic for generating control signals for operating the multiplexers according to a timing scheme having predetermined durations Δt11, Δt22, Δt33, Δt44.

[0119] The predetermined durations Δt11, Δt22, Δt33, Δt44 may be stored in a non-volatile memory (e.g., flash) of the sensor device during a calibration procedure and retrieved from the non-volatile memory during actual use of the sensor device, e.g., by a control logic block, although other solutions are also conceivable. For example, it may be possible to implement the processing circuitry using programmable hardware in which the predetermined durations are hard-coded.

[0120] Note that the graph showing the exemplary composite waveform 1231 is a realistic example for a magnetic source positioned at an angle close to 0°, since (relatively) the amplitude of h1 is close to "+1", the amplitude of h2 is close to "0", the amplitude of h3 is close to "-1", and the amplitude of h4 is close to "0". If the magnetic source were positioned or oriented at an angle of 90°, the amplitude of h1 would be close to "0", the amplitude of h2 would be close to "+1", the amplitude of h3 would be close to "0", the amplitude of h4 would be close to "-1", etc. Such other graphs are not described (or included) herein.

[0121] For completeness, it should be noted that the graph with the bandpass filtered signal 1232 shown in FIG. 12 does not actually match the graph showing the composite waveform 1231 and should actually be shifted about 200° to the left, but the reader will understand that the graph of the bandpass filtered signal shown in FIG. 12 nicely illustrates how the zero crossings need to be determined.

[0122] As mentioned above, the phase φ may be measured using an incremental counter, the counter value indicating the angle or phase φ to be measured may be output, for example, as a digital value, or as a serial value, or as an analog value on an output port of the sensor device.

[0123] In a variant of the sensor device 1202 (not shown), in which the sensor device 1205 comprises, for example, five sensors H1 to H5, the sample period Ts is divided into five time windows w1 to w5 each having a duration of Ts / 5, and each of these five time windows w1 to w5 is partially filled by one of the sensor signals h1 to h5, more specifically over a respective period Δt11 to Δt55, the values ​​of which can be determined during a calibration procedure.

[0124] Figure 13 shows a schematic block diagram of a sensor device 1302, which can be seen as a variation of the sensor device 1202 of Figure 12, with the main difference being that the multiplexer MUX of Figure 12 is replaced by a number of switches and a signal combiner Σ configured to add or subtract two parts of the sensor signal in each timing window w1, w2, w3, w4. It is noted that subtracting two signals with substantially the same amplitude but opposite signs approximately doubles the signal amplitude.

[0125] More specifically, in the example shown in Figure 13: in a first time window w1, the portion Δt11 of the first sensor signal h1 is added or subtracted from the portion Δt13 of the third sensor signal, In a second time window w2, the portion Δt22 of the second sensor signal h2 is added or subtracted from the portion Δt24 of the fourth sensor signal h4 (this is not very visible in FIG. 13 because the amplitudes of h2 and h4 are close to 0 in the example shown). in a third time window w3, the portion Δt31 of the first sensor signal h1 and the portion Δt33 of the third sensor signal h3 are added or subtracted, In the fourth time window w4, portion Δt42 of the fourth sensor signal h4 and portion Δt44 of the fourth sensor signal h4 are added or subtracted (again, this is not very visible in FIG. 13 since in the shown example the amplitudes of h2 and h4 are close to 0).

[0126] As can be seen in FIG. 3, sensors S1 and S3 are positioned diametrically opposite one another, as are sensors S2 and S4.

[0127] As a rule of thumb (and as an initial set of values ​​during a calibration procedure), the periods Δt11 and Δt13 may be selected inversely proportional to the gain of the sensor H1, the periods Δt22 and Δt24 may be selected inversely proportional to the gain of the sensor H2, the periods Δt31 and Δt33 may be selected inversely proportional to the gain of the sensor H3, and the periods Δt42 and Δt44 may be selected inversely proportional to the gain of the sensor H4, although this set of predefined values ​​may not yield the best possible result, as will be explained further. In fact, the "best values" may also compensate for some non-idealities of magnetic sources, such as material defects, mounting offsets, tilt, etc.

[0128] An advantage is that the position or orientation φ provided by the sensor device 1302 of FIG. 13 is less sensitive to external disturbance fields.

[0129] Everything else described above for the sensor device of FIG. 12 is also applicable here mutatis mutandis.

[0130] FIG. 14 shows a schematic block diagram of a sensor device 1402, which can be seen as a variation of the sensor device 1302 of FIG. 13 and thus as a further variation of the sensor device 1202 of FIG.

[0131] The main difference between the sensor device 1402 of FIG. 14 and the sensor device 1302 of FIG. 13 is that the signal combiner Σ is configured to add or subtract more than two, e.g., four, parts of the sensor signal, e.g., three sensor signals, or four sensor signals, in each timing window w1, w2, w3, w4.

[0132] More specifically, in the example shown in FIG. 14, the portion to be added or subtracted in the first time window w1 can be written as sum1=a11*h1+a12*h2+a13*h3+a14*h4, where a11, a12, a13, a14 can be positive or negative coefficients, and the signal combiner Σ adds the signal portion if the sign of the coefficient is positive, and subtracts the signal portion if the sign of the coefficient is negative. The portion of h1 is the time portion over a period Δt11 that is equal to or proportional to the absolute value of the coefficient a11. Or, it is written in mathematical terms Δt11=abs(a11). Similarly, Δt12=abs(a12), Δt13=abs(a13), Δt14=abs(a14).

[0133] Similarly, the signals generated in the second time window w2 can be written as sum2=a21*h1+a22*h2+a23*h3+a24*h4, the signals generated in the third time window w3 can be written as sum3=a31*h1+a32*h2+a33*h3+a34*h4, and the signals generated in the fourth time window w4 can be written as sum4=a41*h1+a42*h2+a43*h3+a44*h4.

[0134] Although one skilled in the art would expect the values ​​of coefficients a12, a14, a21, a23, a32, a34, a41, and a43 to be equal to zero, the inventors have found that coefficients a11-a44 can in fact be used not only to calculate the linear or angular position or orientation of the magnetic field, but also to improve the accuracy (or reduce errors) associated with non-idealities of the sensor array and / or magnetic source. It can also be stated that signals h1-h4 contain position information and redundant information (because there are more than two sensors), but in classical solutions there is no way to extract or use the redundant information present in the signals to improve the signal accuracy. The technique proposed by the present invention makes it possible to use the redundant information to reduce the overall error. This is an important advantage of the present invention. It will be appreciated that, in general, the more sensors there are, the more coefficients can be used to improve the overall accuracy.

[0135] All else discussed above for the embodiment of FIG. 13 is also applicable here mutatis mutandis.

[0136] Calibration Procedure: While finding optimal values ​​for coefficients a11 to a44 in Figure 14 and / or for durations Δt11, Δt22, Δt33, Δt44 in Figure 12 and / or for durations Δt11, Δt13, Δt22, Δt44, Δt31, Δt33, Δt42, Δt44 in Figure 13 is not essential to understanding the operating principle of the present invention, the following paragraphs provide possible methods for finding optimal or sub-optimal values.

[0137] Given the hardware of Figures 12-14 with its timing scheme, the task of finding durations or coefficients can be considered as an optimization procedure to find a "global optimum" or a "local optimum" in a multidimensional space. As already mentioned above, there is probably only one "overall best solution", but there are probably multiple sub-optimal solutions, which, when used in the sensor device or sensor system proposed by the present invention, may not result in the lowest possible error, but may still be able to achieve at least a 2.0-fold error reduction compared to a solution where the entire window w1 is filled with signal h1 and the entire window t2 is filled with signal h2 (without trimming), etc. It is explicitly pointed out that the present invention is not only aimed at a single best solution using the best set of coefficients or periods, but also aimed at sub-optimal solutions, as long as they provide at least a 2.0-fold error reduction.

[0138] Returning to Figure 12 (with 4 sensors), it can be seen that there are only 4 coefficients to be optimized, or in general, if the sensor configuration has N sensors, there are N coefficients to be optimized. In Figure 13 there are 2*N coefficients to be optimized, and in Figure 14 there are up to N*N coefficients to be optimized.

[0139] From these examples, it is clear that the number of coefficients or periods to be optimized depends on the number of sensors (N) and on the number of signals that the hardware can add or subtract in a single time window. The latter may depend on the hardware implementation, e.g., on the number of adders or subtractors present in the combiner circuit Σ. This is a designer's choice.

[0140] To account for imperfections or non-idealities of the magnetic source, such as tilt, mounting offsets, etc., the calibration procedure must be performed on the configuration including the magnetic source and the sensor device that will be used in combination in the final product. In practice, optimal values ​​typically differ for each individual sensor and magnet.

[0141] Once a sensor layout has been selected (e.g., having four horizontal Hall elements as shown in FIG. 3) and the number of coefficients to be optimized has been selected (values ​​ranging from N to N*N), the following algorithm can be used to find a “local minimum” for the angular position sensor system: a) providing a hardware setup comprising a magnetic source and a sensor device (e.g. the sensor device of FIG. 12 or FIG. 13 or FIG. 14 ) and connecting the magnetic source with a precise reference angular sensor device (e.g. using an optical encoder mounted on the same shaft) that can be used to determine the actual mechanical position of the magnetic source; b) selecting an initial set of coefficient values; c) applying this set of coefficient values, positioning the magnetic source at various positions, for example over a full stroke of 360°, in steps of, for example, 5°, and at each step determining the angular position φ provided by the sensor device, calculating the difference (i.e. the error) between the actual (mechanical) position and the position provided by the sensor device, and storing the maximum or worst error as the "error" of this set of coefficient values; d) modifying one of the coefficients (e.g., by increasing or decreasing it) and repeating step c) for the modified set of coefficients and storing the "worst case error" for this modified set of coefficients; e) Starting with the initial set of coefficients, repeat step d) for each of the coefficients to determine which modification provides the best improvement, and then consider the initial set of coefficients with this one modified coefficient that provides the best improvement as the new "initial set" of coefficients. f) Repeating steps c)-e) a predetermined number of times (e.g., up to 100 times, or up to 250 times) or until the resulting error is less than a predetermined threshold (e.g., less than 5°, or less than 4°, or less than 3°, or less than 2°).

[0142] In other words, the algorithm starts with an initial set of coefficient values ​​and incrementally improves the coefficient set by modifying one coefficient at a time, i.e., the coefficient that provides the greatest improvement when increased or decreased by a fixed value, e.g., ±0.05. It has been noted that such incremental improvement approaches do not always find a "global optimum", but typically find a "local optimum" in the coefficient space.

[0143] Many variations of this algorithm are possible: for example, the above algorithm can first be performed in a coarse manner by moving the magnetic source in steps of, for example, 60° and modifying the coefficients in steps of ±0.05, and when a near-optimal solution for the set of coefficients is found, the algorithm can be repeated with smaller angle rotations (e.g., in steps of 30°) and / or smaller coefficient steps (e.g., ±0.02).

[0144] It goes beyond the scope of the present invention to describe the most efficient algorithm for finding the "supra" optimal set of parameters, but it will be appreciated that the above algorithm is sufficient to enable the present invention.

[0145] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive.

[0146] From reading the present disclosure, other modifications will be apparent to persons skilled in the art, and may involve other features which are already known in the art and which may be used instead of or in addition to features already described herein.

[0147] Variations to the disclosed embodiments can be understood and effected by the skilled artisan, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality of elements or steps. The mere fact that certain measures are recited in different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0148] Any reference signs in the claims should not be construed as limiting the scope. The following is an invention described at the beginning of the present application. <Claim 1> A sensor device (1202, 1302, 1402) for determining the position of a magnetic source movable relative to said sensor device or vice versa, or for determining the orientation of a substantially uniform magnetic field, e.g. the Earth's magnetic field, a substrate comprising a plurality of at least two magnetic sensors configured to provide a plurality of at least two sensor signals; a signal combiner (MUX, Σ) configured to combine said sensor signals (h1, h2, h3, h4) into a combined waveform (1231, 1331, 1431); a processing circuit configured to extract the position or orientation from the composite waveform (1231, 1331, 1431), the signal combiner (MUX, Σ) is configured to generate the composite waveform (1231, 1331, 1431) by including one or more portions of the sensor signals (h1, h2, h3, h4) for respective predetermined durations (Δt11 to Δt44); The predetermined durations (Δt11 to Δt44) are determined during a calibration procedure; A sensor device, characterized in that at least two of the predetermined durations (Δt11 to Δt44) have different values. <Claim 2> The sensor device (1202, 1302, 1402) of claim 1, wherein the processing circuit comprises a bandpass filter and a phase detector. <Claim 3> A sensor device (1202, 1302, 1402) as claimed in claim 1 or 2, wherein the signal combiner (MUX, Σ) is configured to generate the composite waveform (1231, 1331, 1431) according to a timing scheme having a predetermined duration Ts, the predetermined duration being divided into several timing windows (w1, w2, w3, w4) each having a duration of Ts / N, where N is the number of sensors. <Claim 4> The sensor device (1202) of claim 3, wherein the signal combiner (MUX, Σ) is configured to include only one portion of the sensor signal (h1, h2, h3, h4) in each timing window (w1, w2, w3, w4). <Claim 5> the number of sensors is even; the sensors are equidistantly spaced on an imaginary circle; 4. The sensor device (1302) of claim 3, wherein the signal combiner (MUX, Σ) is configured to add or subtract portions of two diametrically opposed sensors in each timing window (w1, w2, w3, w4). <Claim 6> The sensor device (1402) of claim 3, wherein the signal combiner (MUX, Σ) is configured to add or subtract portions of at least two or at least three or at least four sensor signals (h1, h2, h3, h4) in each timing window (w1, w2, w3, w4). <Claim 7> The sensor device (1402) of claim 6, wherein the signal combiner (MUX, Σ) is configured to add or subtract a portion of each sensor signal (h1, h2, h3, h4) in each timing window (w1, w2, w3, w4), each portion having a predetermined duration (Δt11 to Δt44). <Claim 8> A sensor device (1402) according to claim 6 or 7, wherein the durations (Δt11 to Δt44) of at least two or at least three parts to be added or subtracted have different values ​​from each other. <Claim 9> The magnetic source (101) is a permanent magnet that is rotatable around a rotation axis, A sensor device (1202, 1302, 1402) according to any of claims 1 to 8, wherein the determined position is an angular position (φ). <Claim 10> the magnetic source is an elongated structure having one pole pair or having a number of alternating poles; the sensor device is movable relative to the magnetic structure by a fixed distance; A sensor device (1202, 1302, 1402) according to any of the preceding claims, wherein the determined position is a linear position (x) along the elongated structure. <Claim 11> the substantially uniform magnetic field being the Earth's magnetic field or a magnetic field generated by at least one coil; 9. A sensor device (1202, 1302, 1402) according to any one of claims 1 to 8, wherein the determined orientation is an angle (φ) relative to a reference orientation. <Claim 12> some or all of the sensors are configured to measure a magnetic field (Bz) perpendicular to the substrate; or some or all of the sensors are configured to measure magnetic fields (Bx, By, Br, Bt) in a direction parallel to the substrate; or a first subset of sensors configured to measure a magnetic field (Bz) in a direction perpendicular to the substrate and a second subset of sensors configured to measure a magnetic field (Bx, By, Br, Bt) in a direction parallel to the substrate; or some or all of the sensors are configured to measure a radial magnetic field (Br) parallel to the substrate; or A sensor device (1202, 1302, 1402) according to any of claims 1 to 11, wherein some or all of the sensors are configured to measure a circumferential magnetic field (Bt) parallel to the substrate. <Claim 13> A sensor device (1202, 1302, 1402) according to any of claims 1 to 12, wherein the sensor is configured to measure magnetic fields of at least two different orientations. <Claim 14> A sensor device (1202, 1302, 1402) according to any of claims 1 to 13, wherein the sensor elements are located on an imaginary circle, optionally spaced equidistantly. <Claim 15> A sensor device (1202, 1302, 1402) according to any one of claims 1 to 14, The magnetic source (101). <Claim 16> 16. The position sensor system of claim 15, wherein the predetermined durations (Δt11 to Δt44) are determined during a calibration procedure performed with a test setup including the sensor device and the magnetic source.

Claims

1. A sensor device (1202, 1302, 1402) for determining a position of a magnetic source movable relative to said sensor device, or for determining a position of said sensor device movable relative to a magnetic source, or for determining an orientation of a substantially uniform magnetic field, a substrate comprising a plurality of at least two magnetic sensors configured to provide a plurality of at least two sensor signals; a signal combiner (MUX, Σ) configured to combine said sensor signals (h1, h2, h3, h4) into a composite waveform (1231, 1331, 1431) according to a timing scheme corresponding to the arrangement of said sensors; a processing circuit configured to extract said position or orientation from said composite waveform (1231, 1331, 1431), the signal combiner (MUX, Σ) is configured to generate the composite waveform (1231, 1331, 1431) by including one or more portions of the sensor signals (h1, h2, h3, h4) for respective predetermined durations (Δt11 to Δt44); the predetermined durations (Δt11 to Δt44) correspond to the placement of the sensor and are determined during a calibration procedure; A sensor device, characterized in that at least two of the predetermined durations (Δt11 to Δt44) have different values.

2. The sensor device (1202, 1302, 1402) of claim 1, wherein the processing circuitry comprises a bandpass filter and a phase detector.

3. 2. The sensor device (1202, 1302, 1402) of claim 1, wherein the timing scheme has a predetermined duration Ts, the predetermined duration being divided into several timing windows (w1, w2, w3, w4) each having a duration of Ts / N, where N is the number of sensors.

4. The sensor device (1202) of claim 3, wherein the signal combiner (MUX, Σ) is configured to include only one portion of the sensor signal (h1, h2, h3, h4) in each timing window (w1, w2, w3, w4).

5. the number of sensors is even; the sensors are equidistantly spaced on an imaginary circle; The sensor device (1302) of claim 3, wherein the signal combiner (MUX, Σ) is configured to add or subtract portions of two diametrically opposed sensors in each timing window (w1, w2, w3, w4).

6. The sensor device (1402) of claim 3, wherein the signal combiner (MUX, Σ) is configured to add or subtract portions of at least two or at least three or at least four sensor signals (h1, h2, h3, h4) in each timing window (w1, w2, w3, w4).

7. The sensor device (1402) of claim 6, wherein the signal combiner (MUX, Σ) is configured to add or subtract a portion of each sensor signal (h1, h2, h3, h4) in each timing window (w1, w2, w3, w4), each portion having a predetermined duration (Δt11 to Δt44).

8. The sensor device (1402) of claim 6, wherein the durations (Δt11 to Δt44) of at least two or at least three portions to be added or subtracted have different values ​​from each other.

9. The magnetic source (101) is a permanent magnet rotatable about an axis of rotation; The sensor device (1202, 1302, 1402) of claim 1, wherein the position determined is an angular position (φ).

10. the magnetic source is an elongated structure having one pole pair or having a plurality of alternating poles; the sensor device is movable relative to the magnetic structure by a fixed distance; The sensor device (1202, 1302, 1402) of claim 1, wherein the determined position is a linear position (x) along the elongated structure.

11. the substantially uniform magnetic field being the Earth's magnetic field or a magnetic field generated by at least one coil; The sensor device (1202, 1302, 1402) of claim 1, wherein the determined orientation is an angle (φ) relative to a reference orientation.

12. some or all of the sensors are configured to measure a magnetic field (Bz) in a direction perpendicular to the substrate; or some or all of the sensors are configured to measure magnetic fields (Bx, By, Br, Bt) in a direction parallel to the substrate; or a first subset of sensors configured to measure a magnetic field (Bz) in a direction perpendicular to the substrate and a second subset of sensors configured to measure a magnetic field (Bx, By, Br, Bt) in a direction parallel to the substrate; or some or all of the sensors are configured to measure a radial magnetic field (Br) parallel to the substrate; or The sensor device (1202, 1302, 1402) of claim 1, wherein some or all of the sensors are configured to measure a circumferential magnetic field (Bt) parallel to the substrate.

13. The sensor device (1202, 1302, 1402) of claim 1, wherein the sensor is configured to measure magnetic fields of at least two different orientations.

14. The sensor device (1202, 1302, 1402) of claim 1, wherein the sensors are located on an imaginary circle, optionally spaced equidistantly.

15. A sensor device (1202, 1302, 1402) according to claim 1, The magnetic source (101).

16. 16. The position sensor system of claim 15, wherein the predetermined time duration (Δt11 to Δt44) is determined during a calibration procedure performed with a test setup including the sensor device and the magnetic source.

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