Magnetic position sensor and calibration thereof

Abstract

The invention discloses a magnetic position sensor and calibration thereof. In described examples, a position sensor (200) may include: a first magnetic field sensor unit (212) having a first sensor output; a second magnetic field sensor unit (214) having a second sensor output; one or more coils (222, 224) having one or more footprints overlapping the first magnetic field sensor unit and the second magnetic field sensor unit; and a processing circuit (524) having a first sensor input, a second sensor input, a current terminal, and a sensing output, the first sensor input coupled to the first sensor output, the second sensor input coupled to the second sensor output, and the current terminal coupled to the one or more coils (222, 224).

Description

Technical Field

[0001] The present description relates to magnetic position sensors and, more particularly, to systems and methods for calibrating magnetic position sensors. Background Art

[0002] There are several different ways to sense position. For example, one available option for position measurement includes using a Hall Effect sensor. A Hall Effect sensor is configured to measure a magnetic field and produce an output voltage representative of the sensed field. The output voltage can be converted into a position measurement for further processing and control. Summary of the invention

[0003] In the described example, a magnetic position sensor may include: a first magnetic field sensor unit having a first sensor output; a second magnetic field sensor unit having a second sensor output; one or more coils having one or more coverage areas overlapping the first magnetic field sensor unit and the second magnetic field sensor unit; and a processing circuit having a first sensor input, a second sensor input, a current terminal and a sensing output, the first sensor input being coupled to the first sensor output, the second sensor input being coupled to the second sensor output, and the current terminal being coupled to the one or more coils.

[0004] In the described example, a sensor device may include: a semiconductor die; a first magnetic field sensor unit having a first sensor output, which is on a first side of the semiconductor die; a second magnetic field sensor unit having a second sensor output, which is on a second side of the semiconductor die opposite to the first side; one or more coils having one or more coverage areas overlapping the first magnetic field sensor unit and the second magnetic field sensor unit; and a processing circuit having a first sensor input and a second sensor input, a current terminal and a processing output, the first sensor input being coupled to the first sensor output, the second sensor input being coupled to the second sensor output, and the current terminal being coupled to the one or more coils.

[0005] In the described example, a method may include: providing a calibration current to one or more coils, the coils having one or more coverage areas overlapping with a first magnetic field sensor unit and a second magnetic field sensor unit of a sensor device; receiving a first sensor signal from the first magnetic field sensor unit, the first sensor signal representing one or more calibration magnetic fields and a second magnetic field provided by the one or more coils in response to the calibration current; receiving a second sensor signal from the second magnetic field sensor unit, the second sensor signal representing one or more calibration magnetic fields and a third magnetic field; extracting a first measurement value of one or more calibration magnetic fields and a second measurement value of the second magnetic field from the first sensor signal; extracting a third measurement value of one or more calibration magnetic fields and a fourth measurement value of the third magnetic field from the second sensor signal; and providing a signal representing a position at a position output based on the first measurement value, the second measurement value, the third measurement value, and the fourth measurement value. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1A is a schematic diagram of an example on-axis position sensing system.

[0007] Figure 1B is a schematic diagram of an example off-axis position sensing system.

[0008] Figure 1C is a schematic diagram of an example linear position sensing system.

[0009] Figure 2 is a schematic diagram illustrating a top plan view of an example semiconductor device including a magnetic position sensor.

[0010] Figure 3 is a schematic diagram illustrating a top plan view of an example magnetic field sensor unit of a magnetic position sensor.

[0011] Figure 4A , Figure 4B , Figure 4C and Figure 4D is a schematic diagram illustrating a top plan view of an example of a semiconductor device including a magnetic position sensor.

[0012] Figure 4E and Figure 4F is a schematic diagram illustrating a cross-sectional view of an example magnetic position sensor.

[0013] Figure 5 is a schematic diagram showing an example circuit for magnetic position sensing with single-source automatic calibration.

[0014] Figure 6 is a schematic diagram of example internal components of a magnetic position detection system.

[0015] Figure 7 , Figure 8 and Fig. 9 is a schematic diagram illustrating an example calibration technique for a magnetic position sensor.

[0016] Fig.10 is a schematic diagram illustrating a top plan view of an example integrated circuit (IC) for a magnetic position sensing system.

[0017] Fig.11 is a schematic diagram illustrating a top plan view of another example semiconductor device including a magnetic position sensor.

[0018] Fig.12 is a flow chart illustrating an example method for magnetic position sensing and calibration. DETAILED DESCRIPTION

[0019] The present specification relates to magnetic position sensors and systems and methods for calibrating magnetic position sensors, such as providing stray field immune position sensing. Typically, high accuracy is desired for rotational / linear position sensing. For example, certain automotive applications may have strict tolerances that are required to be met by the International Standards Organization (ISO). Examples of such requirements include <0.5 degree angular error drift, stray field immunity of up to 5mT DC field in any direction, etc. Although a magnetic position sensor may include multiple magnetic field sensors (e.g., Hall effect sensors / elements) to provide differential signals for position sensing and stray magnetic field elimination, gain mismatches between magnetic field sensors may result in incomplete elimination of stray magnetic fields in the sensor output, which may reduce position sensing accuracy. For example, sensitivity mismatches and sensitivity drifts associated with changes in temperature, stress, or humidity may result in higher angular error drifts. In addition, the distance between magnetic field sensors of a magnetic position sensor providing a differential output may be maximized (e.g., by placing magnetic field sensors on opposite edges / corners of a die) to generate a higher differential signal, but the magnetic field sensor may be more susceptible to sensitivity mismatches due to the increase in separation distance. All of these may increase gain mismatches and reduce position sensing accuracy.

[0020] As described herein, a magnetic position sensor device includes a circuit system that supports automatic calibration operation to mitigate the above-mentioned gain errors, such as sensitivity mismatch and sensitivity drift. According to one example, the magnetic position sensor includes a plurality of magnetic field sensor units and one or more coils, wherein the one or more coils have one or more coverage areas overlapping with the corresponding magnetic field sensor units. In an example where there is more than one coil, the coils are connected in series, and a calibration current can be injected into all coils to generate one or more calibration magnetic fields for each magnetic field sensor unit. Each sensor unit includes one or more Hall effect elements, which are configured to generate a sensor voltage in response to a sensed magnetic field. The sensed magnetic field may include, for example, a combination of an external magnetic field sensed by a plurality of magnetic field sensor units, a calibration magnetic field generated by a coil, and / or a stray magnetic field, and the sensor voltage generated by each sensor unit may represent a combination of these magnetic fields. As described herein, the magnetic position sensor (or associated circuit system) may extract a calibration component from the sensor voltage and calculate a gain factor (or gain corrector factor) based on the calibration component and a calibration magnetic field strength determined based on, for example, a known calibration current. The magnetic position sensor can also be configured to implement gain correction on the signal path (or signal chain) of each sensor unit using a gain factor / gain correction factor, thereby mitigating gain errors between sensor units caused by sensitivity mismatch and sensitivity drift. By mitigating or even eliminating gain errors, stray field immunity can be achieved. In addition, since the same calibration current is injected into all coils, errors associated with inaccurate calibration currents can be offset based on ratiometric angle or position calculations determined from the corresponding sensor voltages.

[0021] In addition, one or more coils can be used as test coils coupled to an external current source. The external current source can supply test currents for trimming in wafer testing and / or bench testing, which can achieve a reduction in testing costs.

[0022] Figure 1A is a schematic diagram of an on-axis position sensing system 110 that may include circuitry to support automatic calibration as described herein. The on-axis position sensing system 110 may include a magnetic position sensor 112 having a center vertically aligned with the center of a rotating counter-rotating magnet 114. The center of the magnetic position sensor 112 is also aligned with the axis of rotation 116. The magnetic position sensor 112 may include a semiconductor die having a horizontal Hall effect element to measure an out-of-plane magnetic field (e.g., along the z-axis) that changes due to the rotation of the magnet, and the output of the horizontal Hall effect element may be processed to calculate the rotation angle of the magnet 114. It should be understood that the magnetic position sensor 112 may be located above or below the magnet 114 along the axis 116.

[0023] Figure 1Bis a schematic diagram of an off-axis position sensing system 150 that may include circuitry to support automatic calibration as described herein. The off-axis position sensing system 150 may include a magnetic position sensor 152 located at the periphery of a rotating counter-rotating magnet 154 and away from (e.g., not coincident with) the magnet's rotational axis 156, such as Figure 1B Magnetic position sensor 152 may include a semiconductor die having vertical Hall effect elements to measure the changing in-plane magnetic field (e.g., along the x-axis and y-axis) due to the rotation of the magnet, and the output of the horizontal Hall effect elements may be processed to calculate the rotation angle of magnet 154.

[0024] Figure 1C is a schematic diagram of a linear position sensing system 170 that can include circuitry to support automatic calibration as described herein. The linear position sensing system 170 can include a magnetic position sensor 172. The magnetic position sensor 172 can measure the position (e.g., relative to the magnetic position sensor 72) and / or linear movement of a magnet 174 along an axis 176. The magnetic position sensor 172 can include a vertical Hall effect element to measure a changing in-plane magnetic field (e.g., along the x-axis or y-axis), and a horizontal Hall effect element to measure an out-of-plane magnetic field (e.g., along the z-axis) that changes due to movement of the magnet, and the output of the horizontal Hall effect element can be processed to determine the position and / or movement of the magnet 174.

[0025] As described above, each of the magnetic position sensors 112, 152, and 172 may include a plurality of magnetic field sensors, each of which includes one or more Hall effect elements. Some magnetic field sensors are paired to sense magnetic fields having opposite directions and generate differential signals (e.g., differential voltage signals) representing the difference between opposite magnetic fields. This arrangement can offset the stray magnetic field components in the differential signal and improve the accuracy of position sensing. However, the gain mismatch between the magnetic field sensors caused by sensitivity mismatch and sensitivity drift associated with changes in temperature, stress, or humidity, for example, may lead to higher angular error drift, etc., which may lead to incomplete elimination of stray magnetic field components, which may reduce the accuracy of position sensing. In addition, in order to maximize / increase the differential signal, the distance between a pair of magnetic field sensors may be increased by, for example, placing a pair of Hall effect elements at opposite corners and / or edges of a semiconductor die. However, due to the increase in separation distance, the magnetic field sensor may be more susceptible to sensitivity mismatch and further increase gain mismatch.

[0026] Figure 22 is a top plan view of an example magnetic position sensor 200 that can address at least some of the above issues. The magnetic position sensor 200 can include a semiconductor die 202 and one or more magnetic field sensor units 212, 214, 216, 218 formed on the die. For example, the magnetic position sensor 200 can include a first magnetic field sensor unit 212, a second magnetic field sensor unit 214, a third magnetic field sensor unit 216, and a fourth magnetic field sensor unit 218. Each magnetic field sensor unit 212, 214, 216, 218 can generate a corresponding sensor signal (e.g., a voltage) in response to a magnetic field measured by the corresponding magnetic field sensor unit. For example, the first magnetic field sensor unit 212 can generate a first sensor signal in response to a magnetic field 213, the second magnetic field sensor unit 214 can generate a second sensor signal in response to a magnetic field 215, the third magnetic field sensor unit 216 can generate a third sensor signal in response to a magnetic field 217, and the fourth magnetic field sensor unit 218 can generate a fourth sensor signal in response to a magnetic field 219. Each of the magnetic fields 213, 215, 217, and 219 may include a combination of multiple magnetic fields, such as an external magnetic field (denoted by B cos and B sin Indicated by), stray magnetic field (marked by B str ) and the calibration magnetic field generated by the magnetic position sensor 200 (denoted by B cal Marking), as described below. Figure 2 In the example shown, the magnetic field is shown in a direction normal to the surface of semiconductor die 202 (eg, along the z-axis). In other examples, the magnetic field may be parallel to the surface of semiconductor die 202 (eg, along the x- and y-axes).

[0027] The first magnetic field sensor unit 212, the second magnetic field sensor unit 214, the third magnetic field sensor unit 216, and the fourth magnetic field sensor unit 218 are spatially arranged spaced apart from each other across a given surface of the semiconductor die 202. According to one example, the first magnetic field sensor unit 212 may be located at a junction of a cross-side edge (e.g., a first corner) of the semiconductor die 202 on a given surface, and the second magnetic field sensor unit 214 may be located at a junction of a cross-side edge (e.g., a second corner) opposite to the first side on a given surface of the semiconductor die 202. In addition, the third magnetic field sensor unit 216 and the fourth magnetic field sensor unit 218 may be on the same side of the semiconductor die 202, but at a corner diametrically opposite to the first sensor unit and the second sensor unit. For example, the first sensor unit, the second sensor unit, the third sensor unit, and the fourth sensor unit may be located at or near a corner of the semiconductor die 202. The first magnetic field sensor unit 212 and the second magnetic field sensor unit 214 may be a pair configured to measure a first opposite external magnetic field (Bcos ) and generates a differential signal representing the difference between the first opposite external magnetic field. In addition, the third magnetic field sensor unit 216 and the fourth magnetic field sensor unit 218 can be another pair, which is configured to measure the second opposite external magnetic field (B sin ) and generates a differential signal representing the difference between the second opposite external magnetic field. To maximize the differential signal, the first sensor unit 212 and the second sensor unit 214 are spaced apart along the first diagonal axis 260 of the semiconductor die 202, and the third sensor unit 216 and the fourth sensor unit 218 are spaced apart along the second diagonal axis 262 of the semiconductor die 202.

[0028] The magnetic position sensor 200 may include one or more coils having one or more footprints that overlap the magnetic field sensor units 212, 214, 216, 218. One or more of the coils may be formed on one or more metal layers on the die and may have a square shape with right angle corners and / or chamfered corners. One or more of the coils may also have other shapes, such as circular, elliptical, hexagonal, octagonal, etc. Figure 2 Each coil can have multiple concentric windings. Figure 2 In the example of , the magnetic position sensor 200 includes a first coil 222, a second coil 224, a third coil 226, and a fourth coil 228, the first coil 222 having a first coverage area overlapping the first magnetic field sensor unit, the second coil 224 having a second coverage area overlapping the second magnetic field sensor unit, the third coil 226 having a third coverage area overlapping the third magnetic field sensor unit, and the fourth coil 228 having a fourth coverage area overlapping the fourth magnetic field sensor unit. The first coil 222 and the second coil 224 can also be spaced apart along the first diagonal axis 260, and the third coil 226 and the fourth coil 228 can also be spaced apart along the second diagonal axis 262. Each of the respective coils 222, 224, 226, and 228 is coupled in series by an electrical connection extending between the paired coils. The first coil 222 can surround the first core region 232, the second coil 224 can surround the second core region 234, the third coil 226 can surround the third core region 236, and the fourth coil 228 can surround the fourth core region 238. The footprint of the coil may include the spatial region or area that the coil projects orthogonally onto the die 202. The core area includes the area surrounded by the coil and the area directly below or above the area.

[0029] exist Figure 2 In the example of FIG. 1 , the magnetic position sensor 200 may be Figure 1A A portion of an on-axis position sensing system 110 (e.g., a magnetic position sensor 112), Figure 1BA portion of an off-axis position sensing system 150 (e.g., a magnetic position sensor 152), or Figure 1C The magnetic field sensor units 212, 214, 216, 218 may each have an in-plane (vertical) or out-of-plane (horizontal) Hall effect element, and the Hall effect element may be in the core region (e.g., Figure 2 The following table provides a summary of the type of Hall effect element used for each type of magnetic position sensor:

[0030]

[0031] Table 1

[0032] As described herein, coils 222, 224, 226, and 228 can be connected in series. For example, first coil 222, second coil 224, third coil 226, and fourth coil 228 can all be connected in series and coupled to current source 250, which can be implemented on semiconductor die 202. In addition, or as an alternative, the input to one or more of coils 222, 224, 226, and 228 can be coupled to an external current terminal, as described herein (e.g., see Fig.10 ). The current source 250 can be used to inject current (eg, I cal ) for automatic calibration. For example, the injected automatic calibration current I cal The current flows through the first coil 222, the second coil 224, the third coil 226 and the fourth coil 228 in series, and induces a corresponding calibration magnetic field B for each magnetic field sensor unit 212, 214, 216, 218. cal In response to the corresponding induced calibration magnetic field B cal , each magnetic field sensor unit 212, 214, 216, 218 generates a corresponding sensor output (eg, a first sensor output, a second sensor output, a third sensor output, a fourth sensor output, respectively) as a voltage. Automatic calibration current I cal It can be an alternating current (AC) signal, or a periodic signal with a frequency outside the frequency of the rotation / movement to be sensed by the magnetic field sensor unit. cal flows through the coil, thus calibrating the magnetic field B cal The same strength may be provided for the first coil 222, the second coil 224, the third coil 226 and the fourth coil 228. Depending on the calibration current I through the coil cal flow direction, calibrate magnetic field B cal The directions can also be the same or opposite.

[0033] As described in this article, due to the same current I cal is injected into each of the one or more coils 222, 224, 226, and 228, and thus any error associated with the calibration current (e.g., the amount of injected current is different from the target amount) can be offset in a ratiometric manner, such as shown in equation (1), and stray field suppression can be achieved to improve the accuracy of the corresponding position calculation. In other words, even if the headroom of each coil is reduced, the series connection of all one or more coils distributed across the semiconductor die 202 (surrounding the single, double, or four Hall effect sensors of each magnetic field sensor unit) ensures matching calibration currents. Specifically, since a single current source can inject the same current into each of the coils 222, 224, 226, and 228, the injected current (e.g., I cal ) can be inherently nullified.

[0034] As another example, in an example where the magnetic position sensor 200 is an on-axis magnetic position sensor, B cos and B sin is the external magnetic field out of plane relative to the Hall effect elements of sensor units 212, 214, 216, and 218, and is related to the magnetic field B generated by the rotating magnet (e.g., magnet 114) through angular position θ and trigonometric functions (sine and cosine). For example, B cos is related to the magnetic field B by cos(θ), and B sin is related to the magnetic field B by sin(θ). The angular position θ can be calculated from the sensed magnetic field (as represented by the sensor output voltage) such as shown in equations (1) to (5):

[0035] V 1 =G 1 (-B cos +B str +B cal ) (1)

[0036] V 2 =G 2 (B cos +B str +B cal ) (2)

[0037] V 3 =G 3 (-B sin +B str +B cal ) (3)

[0038] V 4 =G 4 (Bsin +B str +B cal ) (4)

[0039]

[0040] In equation 1-4, G 1 represents the gain (or sensitivity factor) of the sensor unit 212 when converting the sensed magnetic field into the sensor output voltage, and V 1 represents the voltage output by the sensor unit 212. G 2 represents the gain (or sensitivity factor) of the sensor unit 214 when converting the sensed magnetic field into the sensor output voltage, and V 2 represents the voltage output by the sensor unit 214. G 3 represents the gain (or sensitivity factor) of the sensor unit 216 when converting the sensed magnetic field into the sensor output voltage, and V 3 represents the voltage output by the sensor unit 216. G 4 represents the gain (or sensitivity factor) of the sensor unit 218 when converting the sensed magnetic field into the sensor output voltage, and V 4 represents the voltage output by the sensor unit 218 .

[0041] In the case where the magnetic position sensor 200 is an off-axis magnetic position sensor, the sensor units 212, 214, 216, and 218 may include in-plane Hall effect elements to measure the magnetic field B in the xy plane. x1 , B x3 , B y1 and B y3 , and the angular position θ can be calculated from the sensed magnetic field (as represented by the sensor output voltage) based on the following equation (6):

[0042]

[0043] Based on I cal and the resulting calibration magnetic field B sensed by the corresponding sensor unit cal , a calibration factor may be calculated for each magnetic field sensor unit 212, 214, 216, 218 (e.g., by Figure 5 In this way, corresponding calibration factors (or gains G ) can be determined for the magnetic field sensor units 212 , 214 , 216 , 218 . 1 , G 2 , G 3 and G 4) to implement gain correction for each magnetic field sensor unit 212, 214, 216, 218. Therefore, gain correction can be implemented during operation (e.g., continuously or periodically) to provide an automatic calibration function for the magnetic position sensor 200. By adjusting the gain, it is possible to adjust the gain at V 1 and V 2 The difference between V 3 and V 4 The difference between the two eliminates the stray magnetic field B. str voltage component, thereby achieving stray magnetic field immunity.

[0044] As another example, in response to the calibration current I cal The magnetic field sensor units 212, 214, 216, 218 may generate one or more corresponding sensor signals (e.g., a first sensor signal, a second sensor signal, a third sensor signal, and a fourth sensor signal) and transmit the sensor signals to a signal processing circuit (e.g., see Figure 5-Figure 6 ). The first sensor signal may represent one or more first magnetic fields 213 detected by the first magnetic field sensor unit 212, the second sensor signal may represent one or more second magnetic fields 215 detected by the second magnetic field sensor unit 214, the third sensor signal may represent one or more third magnetic fields 217 detected by the third magnetic field sensor unit 216, and the fourth sensor signal may represent one or more fourth magnetic fields 219 detected by the fourth magnetic field sensor unit 218.

[0045] As described herein, each of the sensor signals may represent one or more magnetic fields detected at each respective magnetic field sensor unit 212, 214, 216, 218. Examples of one or more of the magnetic fields may include a magnetic field generated by a calibration current I cal The induced calibration magnetic field B cal , a common stray magnetic field B across the semiconductor die 202 str , and a time-varying magnetic field (B) in response to the field provided by an object (e.g., a magnet) whose position is to be determined sin , B cos , B x1 , B x3 , B y1 , B y3 ).

[0046] Thus, the first sensor signal may represent one or more calibration magnetic fields and a first external magnetic field (eg, B sin , B cos , B x1 , B x3 , B y1 , By3 ), the second sensor signal may represent one or more calibration magnetic fields and a second magnetic field (e.g., B sin , B cos , B x1 , B x3 , B y1 , B y3 ), the third sensor signal may represent one or more calibration magnetic fields and a third external magnetic field (e.g., B sin , B cos , B x1 , B x3 , B y1 , B y3 ), the fourth sensor signal may represent one or more calibration magnetic fields and a fourth external magnetic field (e.g., B sin , B cos , B x1 , B x3 , B y1 , B y3 Since the same current is injected into all coils 222, 224, 226, 228, the calibration current I cal Any errors associated are cancelled out based on the set of ratios of equations (1)-(6) and may not appear as error components in the differential signal provided by the sensor unit.

[0047] Figure 3 FIG. 3 is a top plan view of an example magnetic field sensor unit 300 of a magnetic position sensor. The magnetic field sensor unit 300 may be Figure 2 A portion of the magnetic field sensor units 212 , 214 , 216 , 218 . Figure 3 The example magnetic field sensor unit 300 includes four Hall effect elements (e.g., sensors) 312, 314, 316, 318 at respective corners of the magnetic field sensor unit 300, and includes a coil 322 having a footprint that overlaps the magnetic field sensor unit 500 and surrounds its core region 332 that surrounds the Hall effect elements 312, 314 and 316, 318. It should be understood that any number (e.g., 1, 2, 4, etc.) of Hall effect elements may be implemented on the magnetic field sensor unit 300.

[0048] Figure 4A4 is a top plan view of another example magnetic field sensor unit 402 and coil 422 that may be part of magnetic position sensor 200. Magnetic field sensor unit 402 and coil 422 may be part of an off-axis magnetic position sensor and include in-plane Hall effect elements 412 and 414 and outer core region 424 that overlap coil 422. In some examples, Hall effect element 412 may be configured to sense a magnetic field along the x-axis (e.g., a combination of a calibration magnetic field generated by coil 422 and an external magnetic field), and Hall effect element 414 may be configured to sense another magnetic field along the y-axis (e.g., a combination of a calibration magnetic field generated by coil 422 and another external magnetic field).

[0049] Figure 4B 4 is a top plan view of another example magnetic field sensor unit 402 and coil 422 that may be part of magnetic position sensor 200. Magnetic field sensor unit 402 and coil 422 may be part of a magnetic linear position sensor and include in-plane Hall effect elements 412 and 414 overlapping coil 422 and external core region 424, and out-of-plane Hall effect element 426 in core region 424. Hall effect element 426 may sense a magnetic field along the z-axis (e.g., a combination of a calibration magnetic field generated by coil 422 and an external magnetic field). Figure 4B The arrangement allows generating in-plane and out-of-plane calibration magnetic fields for calibrating the magnetic field sensor unit 402 comprising in-plane and out-of-plane Hall effect elements.

[0050] Figure 4C and Figure 4D is a top plan view of additional examples of magnetic field sensor units 402 and coils 422. Figure 4C and Figure 4D , the coil 422 may include two unequal windings 422a and 422b. Figure 4C , windings 422a and 422b are connected via an underground channel portion 422c to allow the calibration current I cal From winding 422a to winding 422b. Figure 4C In the calibration current I cal The magnetic field sensor unit 402 may include an in-plane Hall effect element 412 / 414 located below a portion of windings 422a and 422b to sense an in-plane calibration magnetic field 430 (eg, along the x / y axis).

[0051] Figure 4E and Figure 4F is a cross-sectional view of an example magnetic position sensor, such as magnetic position sensor 200 including magnetic field sensor unit 402 and coil 422 . Figure 4E Examples may include out-of-plane Hall effect elements, such as Hall effect element 426. Figure 4E As shown, sensor 400 includes a coil 422 formed in a metal layer. Coil(s) 422 have a footprint that overlaps (e.g., surrounds) a Hall effect element (such as within a polysilicon layer located below the coil). Figure 4E In the example of FIG. 4 , coil 422 does not overlap Hall effect element 426, and Hall effect element 426 is in core region 424. The die also includes circuitry 430 formed within the die that can perform the position sensing functions described herein. Figure 4F An example magnetic position sensor 200 is shown having in-plane Hall effect elements, such as Hall effect elements 412 and 414 , directly beneath (and overlapping) coil 422 .

[0052] Figure 5 is a block diagram of an example system 500 for magnetic position detection. System 500 may include one or more magnetic field sensor units 512, one or more corresponding coils 522, signal processing circuitry 524, position determination circuitry 526, calibration controller 528, and calibration current source 532. System 500 may be part of circuit system 430. In some examples, system 500 may be part of an application specific integrated circuit (ASIC). Various components of system 500, such as calibration controller 528, signal processing circuitry 524, and position determination circuitry 526, may be implemented based on digital logic circuits, or may be implemented as software modules that are then executed by a processor to perform the functions of calibration controller 528, signal processing circuitry 524, and position determination circuitry 526 as described herein.

[0053] like Figure 5 As shown, the signal processing circuit 524 can have one or more inputs coupled to the corresponding outputs of the magnetic field sensor unit 512. Figure 2 Similarly, the signal processing circuit 524 may have a first sensor input coupled to the first sensor output of the first magnetic field sensor unit, a second sensor input coupled to the second sensor output of the second magnetic field sensor unit, a third sensor input coupled to the third sensor output of the third magnetic field sensor unit, and a fourth sensor input coupled to the fourth sensor output of the fourth magnetic field sensor unit.

[0054] The signal processing circuit 524 can have a command terminal 525 connected to the output of the calibration controller 528. The command terminal 525 can also be coupled to the control input of the calibration current source 532. The calibration controller 528 can be configured to provide a calibration current command at 525 to control the calibration current source 532 to provide a calibration current to the one or more coils 522 through an input current terminal 534, which is coupled to the one or more coils 522. Therefore, the calibration controller 528 can control the calibration current source 532 to apply a calibration current to the one or more coils 522 based on the calibration current command. In this way, the system 500 can provide a calibration current through the one or more coils 522 via the current terminal so that the one or more coils 522 generate a corresponding calibration magnetic field to be applied to the corresponding magnetic field sensor unit 512.

[0055] In response to the calibration current being applied to the one or more coils 522, the magnetic field sensor unit 512 can generate corresponding sensor signals representing the detected magnetic field and provide the sensor signals to the signal processing circuit 524. As described herein (e.g., see Equations 1-6), each of the sensor signals can represent multiple magnetic field components. For example, the signal processing circuit 524 can receive a first sensor signal at a first sensor input, a second sensor signal at a second sensor input, a third sensor signal at a third sensor input, and a fourth sensor signal at a fourth sensor input. The first sensor signal can represent one or more calibration magnetic fields and a first external magnetic field (e.g., B sin , B cos , B x1 , B x3 , B y1 , B y3 ), the second sensor signal may represent one or more calibration magnetic fields and a second magnetic field (e.g., B sin , B cos , B x1 , B x3 , B y1 , B y3 ), the third sensor signal may represent one or more calibration magnetic fields and a third external magnetic field (e.g., B sin , B cos , B x1 , B x3 , B y1 , B y3 ), the fourth sensor signal may represent one or more calibration magnetic fields and a fourth external magnetic field (e.g., B sin , B cos , B x1 , B x3 , B y1 , B y3Each of the sensor signals may also include a common stray magnetic field (B) sensed by each corresponding magnetic sensor unit 512. str )’s weight.

[0056] The signal processing circuit 524 can be configured to determine a calibration factor for each of the first magnetic field sensor unit, the second magnetic field sensor unit, the third magnetic field sensor unit, and the fourth magnetic field sensor unit based on the first sensor signal, the second sensor signal, the third sensor signal, and the fourth sensor signal, respectively. The signal processing circuit 524 can apply the calibration factor determined for each magnetic field sensor unit 512 to adjust the gain for the corresponding sensor unit. One or more gains may include a first gain of the first magnetic field sensor, a second gain of the second magnetic field sensor, a third gain of the third magnetic field sensor, and a fourth gain of the fourth magnetic field sensor. The calibration factor can be determined and maintained unchanged, or it can be determined during operation (e.g., continuously or intermittently).

[0057] The signal processing circuit 524 can then generate an output signal at the sensing output based on the corresponding adjusted gains of the first magnetic field sensor unit, the second magnetic field sensor unit, the third magnetic field sensor unit, and the fourth magnetic field sensor unit. The output signal can represent the detected angular position / linear position. In one example, the one or more gains include the average gain of the first magnetic field sensor unit and the second magnetic field sensor unit. In another example, the one or more gains include the average gain of the first magnetic field sensor unit, the second magnetic field sensor unit, the third magnetic field sensor unit, and the fourth magnetic field sensor unit. The position determination circuit 526 can use the output signal to calculate the angle, such as shown in Equation 5.

[0058] Figure 6 is a block diagram of an example signal processing circuit 524 that may be implemented for a multi-channel magnetic position detection circuit. For example, Figure 6 The signal processing circuit 524 is Figure 5 An example of a signal processing circuit 524. Therefore, Figure 6 For a description, see Figure 5 Description of the . Figure 6 In the example of FIG. 1 , an example of on-axis position sensing is shown, where an external out-of-plane magnetic field +B is sensed. cos (pointing out of the paper), -B cos (point to the inside of the paper), +B sin (pointing away from the paper) and -B sin (Pointing into the paper). In some examples, Figure 6 The signal processing circuit 524 can provide off-axis sensing, where + / -B cos Can be affected by in-plane magnetic field + / -B xReplace, and + / -B sin Can be affected by in-plane magnetic field + / -B y In addition, in some examples, Figure 6 The signal processing circuit 524 can provide linear position sensing, where + / -B cos or + / -B sin One of them can be detected by the in-plane magnetic field + / - B x or + / -B y replace.

[0059] The signal processing circuit 524 includes a corresponding signal path (also referred to as a signal chain) for each magnetic field sensor unit, each path including a main path and a calibration path. Each signal path has a corresponding input 602, 604, 606 and 608 and a corresponding output 610, 612, 614 and 616. For example, the first signal path has an analog front end (AFE) 620 having an input 602 coupled to the sensor unit output to receive the sensor signal voltage V 1 . AFE 620 may include an input amplifier and filter circuitry (e.g., a low pass filter) to provide an analog output to an input of an analog-to-digital converter (ADC) 622. ADC 622 may convert the analog output to a corresponding digital signal at ADC output 624, providing the digital signal for processing by a main processing path 626 and a calibration processing path 628. Processing paths 626 and 628 may be located on the same die as the magnetic field sensor unit, or on different circuit systems (e.g., on a printed circuit board). In some examples, signal processing circuit 524 may include a set of AFEs and ADCs that may be shared between different magnetic sensor units.

[0060] The main processing path 626 includes a low pass filter 630 and a gain stage 632. The low pass filter may filter the digital signal at 624 (e.g., V 1 628), and provides a corresponding digital filtered signal to the input of a gain stage 632. Gain stage 632 amplifies the corresponding digital filtered signal based on its variable gain (which is corrected by calibration processing path 628) to provide an output representative of the measured magnetic field.

[0061] The calibration processing path 628 includes an extraction circuit 634 and a calibration correction factor circuit 636. The extraction circuit 634 can extract a measure of the calibration magnetic field (e.g., V 1 For example, the extraction circuit 634 may extract the calibration field using at least one of a bandpass filter, a root mean square (RMS) operation, an autocorrelation operation, or a Fourier transform operation. The extracted calibration field represents V 1The component of the injected calibration current in response to the first sensor unit sensing. As described herein, the calibration current can be injected once, continuously, or intermittently, and can have a frequency outside the frequency of the rotation / movement to be sensed by the magnetic sensor unit. Therefore, V 1 The calibration magnetic field component (V cal1 ) and V 1 The external magnetic field components may have different frequency bands and / or have different frequency characteristics, based on which the extraction circuit 634 may separate the calibration magnetic field and the external magnetic field components.

[0062] The calibration correction factor calculator 636 may calculate a gain correction factor CF based on an extracted calibration signal (eg, provided by the extraction circuit 634). 1 . Gain correction factor CF 1 is applied to gain stage 632 to set the gain for the corresponding first signal processing path, which provides a gain-corrected measurement of the sensed magnetic field at the signal path output 610.

[0063] Each of the other signal processing paths may be configured the same as the first signal processing path and thus configured to be based on the magnetic field sensor output signal V 2 、V 3 and V 4 An individual gain is set for each corresponding signal processing path. That is, each signal processing path of the signal processing circuit 524 can extract the first sensor signal V by performing processing in its corresponding calibration path. 1 , the second sensor signal V 2 , the third sensor signal V 3 and the fourth sensor signal V 4 Each of the associated calibration voltages V cal (For example, V cal1 、V cal2 、V cal3 、V cal4 The signal processing circuit 524 may also be configured to calculate a corresponding gain correction factor CF (eg, CF 1 CF 2 CF 3 CF 4 The gain correction factor may be based on, for example, a calibration voltage (V cal1 、V cal2 、V cal3 、V cal4 ) and a calibration magnetic field, which may be based on a known calibration current I calThus, each signal processing path can provide a corresponding gain-corrected magnetic field measurement at its corresponding path output 610, 612, 614, and 616. It should be understood that the signal processing circuit 524 can be configured to operate in a time-interleaved manner to allow passive or active calculation of gain and / or gain correction factors.

[0064] In addition, each signal processing path of the signal processing circuit 524 provides a signal at 610, 612, 614, and 616 that represents a gain-corrected version of the processed magnetic field signal measurement, each version including a gain-corrected magnetic field component, a stray field component, and a calibration component for the field measured from the object (e.g., a rotating magnet). For example, at 610, the gain-corrected magnetic field signal measurement for the first magnetic field sensor can be represented as:

[0065]

[0066] In equation (7), k 1 is a constant associated with the coil design of the first magnetic field sensor, G 1 / CF 1 is the calibrated gain implemented at gain stage 632 .

[0067] Additionally, the second signal path provides a gain-corrected field signal measurement for the second magnetic field sensor at 612, which may be expressed as:

[0068]

[0069] In equation (8), k 2 is the constant associated with the coil of the second magnetic field sensor, G 2 / CF 2 is the calibrated gain for the corresponding gain stage. The signals at 610 and 612 may be combined (eg, by a subtraction function 640) to provide a gain at 642 equal to 2B cos The output can be determined as follows:

[0070]

[0071] The input sensor voltage V provided by the third magnetic field sensor unit and the fourth magnetic field sensor unit 3 and V 4 The signal processing paths of 614 and 616 can be configured to be identical to provide corresponding gain-corrected magnetic field signal measurements at 614 and 616. The gain-corrected magnetic field signal measurements at 614 and 616 are combined (e.g., by subtraction function 650) to provide a value equal to 2B at 652. sinAdvantageously, when the outputs of the corresponding path pairs are combined (e.g., by subtraction functions 642 and 652), stray magnetic field components can be eliminated. By including a filter (e.g., a low pass filter) in the signal path, the calibration field component representing the induced field in response to the calibration current can be removed from the signal. The signal processing circuit 524 can be configured to generate a signal based on the combined output representing the sensed position (e.g., 2B cos and 2B sin , B y3 -B y1 and B x3 -B x1 etc.) to generate a position output signal, such as an angle θ (see, e.g., Equations 5 and 6) and / or a linear position.

[0072] The systems and methods described herein may be implemented to provide calibration (eg, automatic calibration) of each respective signal path and may be used with other configurations of magnetic field sensor units implemented in a magnetic position sensor. Figure 7-Figure 9 is an illustration of different example magnetic field sensor configurations that may implement the automatic calibration techniques described herein. For example, Figure 7 2 shows a signal chain for a pair of magnetic field sensor units 702 and 704 (such as sensor units 212 and 214). Figure 7 As shown, each sensor unit generates a voltage, which includes a voltage for the main input field component B in , stray field component B str and the calibration field component B cal By signal processing and subtraction of the processed signals, a differential signal representing the difference between opposite external magnetic fields can be determined, such as 2B in As shown. Stray field components are common in the differential signal and can be cancelled, and the calibration field component can be isolated and used for automatic calibration of the signal chain gain as described herein. The calibration field component can also be removed from the signal chain (e.g., by filtering). Figure 7 The example configuration allows the gain (or gain correction factor) to be determined for each magnetic sensor unit individually, and the calibration operation can be more efficient in eliminating gain errors between a pair of magnetic field sensor units.

[0073] Figure 8 Another example of a calibration signal chain for a magnetic field sensor unit is shown. Figure 8 As shown, each sensor unit provides a corresponding signal, which includes a signal for the main input field component B in , stray field component B str and the calibration field component B cal Sensor units 802 and 804 can sense opposite external magnetic fields B in and the opposite calibration magnetic field B calIn addition, the sensor units 812 and 814 can sense opposite external magnetic fields B in and the opposite calibration magnetic field B cal The sensor units 802 and 812 can sense the external magnetic field B in the same first direction. in and the opposite calibration magnetic field B cal The sensor units 804 and 814 can sense the external magnetic field B in the same second direction (opposite to the first direction). in and the opposite calibration magnetic field B cal .

[0074] exist Figure 8 In the example, the sensor signals output by the sensor units 802 and 812 may be subtracted to extract the signal 2B. cal-0 The sensor signals output by sensor units 804 and 814 may also be subtracted to extract the calibrated magnetic field components as shown in FIG2B. cal-1 The calibration magnetic field component shown. Calibration magnetic field component 2B cal-0 and 2B cal-1 Can be used for automatic calibration of signal chain gain as described in this article. For example, 2B cal-0 can be used to generate an average gain correction factor for sensor units 802 and 812, and 2B cal-1 The average gain correction factor may be used to generate an average gain correction factor for sensor units 804 and 814. In addition, the sensor signals provided by sensor units 802 and 812 may be summed, the sensor signals provided by sensor units 804 and 814 may also be summed, and the difference between the sum of the sensor signals from sensor units 802 / 812 and the sum of the sensor signals from sensor units 804 / 814 may be determined. The difference (shown as 4B in (or 2B for on-axis sensing sin and 2B cos , and for off-axis sensing is B x1 -B x3 and B y1 -B y3 ) can be expressed as removing the stray magnetic field (B str ) and the calibration magnetic field (B cal ) component of an external magnetic field and can be used for position sensing. Figure 8 The arrangement can reduce the complexity of the operations involved in extracting the calibration component magnetic field component and calculating the gain factor.

[0075] Fig. 9 Another example signal chain for a magnetic field sensor unit is shown. Fig. 9 As shown, each of the sensor units 902 and 904 generates a voltage including a component B for the external magnetic field. in , stray field component Bstr and the calibration magnetic field component B cal The sensor units 902 and 904 sense opposite external magnetic fields and opposite calibration magnetic fields. The signals from the sensor units can be subtracted to remove stray field components and provide components for the main input signal and the calibration component, such as 2B in +2B cal The calibration field component may be isolated and used for automatic calibration of the signal chain gain, such as described herein, to determine an average gain correction factor for sensor units 902 and 904 . Fig. 9 The arrangement can reduce the complexity of the operations involved in extracting the calibration component magnetic field component and calculating the gain factor.

[0076] Fig.10 FIG. 1 is a top plan view of an example integrated circuit (IC) 1000 for a magnetic position sensing system. Fig.10 As shown, IC 1000 includes a plurality of magnetic field sensor units 1002, each of which may have a number of one or more magnetic field sensors (eg, Hall effect sensors), such as those described herein (eg, see Figure 3 ). IC 1000 also includes one or more coils 1004 having one or more corresponding footprints overlapping with sensor unit 1002. Fig.10 In the example of , a corresponding coil is overlaid on each sensor unit, and the coils are connected in series between the current input and output, as shown at 1010 and 1012.

[0077] IC 1000 may include an on-chip current source 1050. The current source may be configured to inject a calibration current into a series-connected arrangement of one or more coils 1004, such as described herein. Fig.10In the example of , the IC also includes a multiplexer (MUX) 1052. MUX 1052 has inputs 1054 and 1056 coupled to respective outputs of current source 1050. MUX 1052 also has inputs 1058 and 1060 coupled to terminals 1062 and 1064, respectively. Terminals 1062 and 1064 may be implemented as conductive pads or pins that are arranged and configured to enable external circuitry to access inputs 1058 and 1060 directly or indirectly through other circuitry. MUX 1052 may select which input or inputs are electrically connected to current inputs and outputs 1010 and 1012 in response to a select signal provided to a control input 1070 of MUX 1052. For example, MUX 1052 may switch between an on-chip current source 1050 or an external current source (not shown) that has its output coupled to terminals 1062 and 1064. MUX 1052 may select on-chip current source 1050 in a first case to inject a calibration current into the coil in response to a selection signal at 1070, such as that provided by a calibration controller (e.g., from Figure 5 5 (e.g., the calibration controller 528 of the IC 1000). In another example, the MUX can select inputs 1058 and 1060 in a second case based on the signal provided to the MUX, while one or more external current terminals 1060 are coupled to terminals 1062 and 1604 to provide current to one or more coils, thereby enabling an external current to be applied to the coil 1004. In one example, an external current source can be connected to terminals 1062 and 1064 to provide an external current to the coil as part of a trimming process, where one or more fuses or register entries can be set during wafer and / or bench testing of the IC 1000. That is, the coil 1004 described herein can be used for multiple purposes, namely, to implement calibration during operation and to perform trimming during device testing.

[0078] Fig.11 1 is a top plan view of another example semiconductor die 1102 of a magnetic position sensor configured to implement automatic calibration. Semiconductor die 1102 may be an example of semiconductor die 202 and may include a single coil 1122 and magnetic field sensor units 1112, 1114. According to an example, single coil 1122 has a single footprint that overlaps multiple magnetic field sensor units 1112, 1114 (e.g., first magnetic field sensor unit and second magnetic field sensor unit). In an example where the position sensing system is on an axis (e.g., a magnetic position sensor such as Figure 1A The single coil 1122 may surround the core region 1132. The first magnetic field sensor unit 1112 and the second magnetic field sensor unit 1114 may be in the core region 1132 (eg, Fig.11as shown), or may overlap with coil 1122 in an off-axis position sensor.

[0079] Fig.12 An example method 1200 for magnetic position sensing using single-source automatic calibration is provided. The method 1200 may include providing 1202 a calibration current to one or more coils having one or more coverage areas overlapping with a first magnetic field sensor unit and a second magnetic field sensor unit of a sensor device. For example, the provision of the calibration current may be implemented by a calibration controller 528, which enables a calibration current source 532 to inject current into the one or more coils, such as described herein. The method 1200 may include receiving 1204 a first sensor signal from a first magnetic field sensor unit. The first sensor signal may represent one or more calibration magnetic fields and a second magnetic field provided by the one or more coils in response to the calibration current. The method 1200 may also include receiving 1206 a second sensor signal from a second magnetic field sensor unit, wherein the second sensor signal represents one or more calibration magnetic fields and a third magnetic field. For example, the signal processing circuit 524 may receive the first sensor signal and the second sensor signal based on the sensor signal provided by the one or more sensor units, such as described herein. The method 1200 may include extracting 1208 a first measurement value of the one or more calibration magnetic fields and a second measurement value of the second magnetic field from the first sensor signal. The method 1200 may include extracting 1210 a third measurement of one or more calibration magnetic fields and a fourth measurement of the third magnetic field from the second sensor signal. The extraction of the first measurement, the second measurement, and the third measurement may be performed by the signal processing circuit 524. The method 1200 may include providing 1212 a signal representing the position at a position output based on the first measurement, the second measurement, the third measurement, and the fourth measurement. For example, providing the signal may be performed by the position determination circuit 526.

[0080] In addition, the method may include determining one or more gains of the first magnetic field sensor unit and the second magnetic field sensor unit based on the first sensor signal and the second sensor signal, generating a first intermediate signal based on the first sensor signal and the one or more gains, generating a second intermediate signal based on the second sensor signal and the one or more gains, extracting third measurement values ​​of the second magnetic field and the third magnetic field based on combining the first intermediate signal and the second intermediate signal, and providing a signal based on the third measurement values.

[0081] In this specification, the term "coupled" may encompass connections, communications, or signal paths that enable a functional relationship consistent with this specification. For example, if device A generates a signal to control device B to perform an action, then: (a) in the first example, device A is coupled to device B through a direct connection; or (b) in the second example, if the intervening component C does not change the functional relationship between device A and device B, device A is coupled to device B through the intervening component C, so that device B is controlled by device A via the control signal generated by device A.

[0082] In this specification, a device that is "configured to" perform a task or function may be configured (e.g., programmed and / or hardwired) by a manufacturer at the time of manufacture to perform that function, and / or may be configurable (or reconfigurable) by a user after manufacture to perform that function and / or other additional or alternative functions. Configuration may be programmable by firmware and / or software of the device, by the construction and / or layout of hardware components and interconnections of the device, or a combination thereof. In addition, a circuit or device described herein as including certain components may instead be configured to be coupled to these components to form the described circuit system or device. For example, a structure described herein as including one or more semiconductor elements (such as transistors), one or more passive elements (such as resistors, capacitors and / or inductors), and / or one or more sources (such as voltage and / or current sources) may instead include only semiconductor elements within a single physical device (e.g., a semiconductor die and / or an integrated circuit (IC) package), and may be configured to be coupled to at least some of the passive elements and / or sources at the time of manufacture or after manufacture (e.g., by an end user and / or a third party) to form the structure.

[0083] The phrase “based on” means “based at least in part on.” Thus, if X is based on Y, then X may be a function of Y and any number of other factors.

[0084] In this specification, unless otherwise specified, “about”, “approximately” or “substantially” before a parameter means within the range of + / - 10% of the parameter, or if the parameter is zero, within a reasonable value range around zero.

[0085] Modifications of the described embodiments are possible within the scope of the claims, and other embodiments are possible.

Claims

1. A position sensor, comprising: a first magnetic field sensor unit having a first sensor output; a second magnetic field sensor unit having a second sensor output; one or more coils having one or more footprints overlapping the first magnetic field sensor unit and the second magnetic field sensor unit; as well as A processing circuit having a first sensor input, a second sensor input, a current terminal, and a sense output, wherein the first sensor input is coupled to the first sensor output, the second sensor input is coupled to the second sensor output, and the current terminal is coupled to the one or more coils.

2. The position sensor according to claim 1, wherein the processing circuit is configured to: providing a calibration current through the one or more coils via the current terminals so that the one or more coils provide one or more calibration magnetic fields; receiving at the first sensor input a first sensor signal representative of the one or more first magnetic fields; receiving at the second sensor input a second sensor signal representative of the one or more first magnetic fields; determining one or more gains of the first magnetic field sensor unit and the second magnetic field sensor unit based on the first sensor signal and the second sensor signal; and A signal representative of position is provided at the sensing output based on the one or more gains. 3 . The position sensor of claim 2 , wherein the one or more gains comprise an average gain of the first magnetic field sensor unit and the second magnetic field sensor unit. 4 . The position sensor of claim 2 , wherein the one or more gains include a first gain of the first magnetic field sensor and a second gain of the second magnetic field sensor.

5. The position sensor of claim 3, wherein the first sensor signal represents the one or more calibration magnetic fields and the second magnetic field, and the second sensor signal represents the one or more calibration magnetic fields and the third magnetic field; and The processing circuit is configured to: extracting first measurements of the one or more calibration magnetic fields from the first sensor signal; extracting second measurements of the one or more calibration magnetic fields from the second sensor signal; determining one or more magnitudes of the one or more calibration magnetic fields based on the calibration current; and The one or more gains are determined based on the first and second measurements and the one or more amplitudes.

6. The position sensor of claim 5, wherein the first measurement value and the second measurement value are extracted based on processing the first sensor signal and the second sensor signal, respectively, using at least one of a bandpass filter, a root mean square operation, an autocorrelation operation, or a Fourier transform operation.

7. The position sensor of claim 5, wherein the processing circuit is configured to: generating a first intermediate signal based on the first sensor signal and the one or more gains; generating a second intermediate signal based on the second sensor signal and the one or more gains; extracting third measurements of the second magnetic field and the third magnetic field based on combining the first intermediate signal and the second intermediate signal; and The signal is provided based on the third measurement value.

8. The position sensor according to claim 7, further comprising a third magnetic field sensor unit having a third sensor output and a fourth magnetic field sensor unit having a fourth sensor output, wherein the one or more coverage areas overlap with the third magnetic field sensor unit and the fourth magnetic field sensor unit; wherein the processing circuit has a third sensor input and a fourth sensor input, the third sensor input being coupled to the third sensor output, and the fourth sensor input being coupled to the fourth sensor output; and The processing circuit is configured to: receiving at the third sensor input a third sensor signal representative of the one or more first and fourth magnetic fields; receiving at the fourth sensor input a fourth sensor signal representative of the one or more first magnetic fields and a fifth magnetic field; generating a third intermediate signal based on the third sensor signal and the one or more gains; generating a fourth intermediate signal based on the fourth sensor signal and the one or more gains; extracting fourth measurements of the fourth magnetic field and the fifth magnetic field based on combining the third intermediate signal and the fourth intermediate signal; and The signal is provided based on a ratio between the third measurement value and the fourth measurement value. 9 . The position sensor of claim 1 , wherein the one or more coils include a single coil having a single footprint that overlaps the first magnetic field sensor unit and the second magnetic field sensor unit. 10 . The position sensor according to claim 9 , wherein the single coil surrounds a core region, and the first magnetic field sensor unit and the second magnetic field sensor unit overlap the core region. 11 . The position sensor of claim 9 , wherein the first magnetic field sensor unit and the second magnetic field sensor unit overlap the single coil.

12. The position sensor of claim 1 , wherein the one or more coils comprise: a first coil having a first footprint overlapping the first magnetic field sensor unit; as well as a second coil having a second footprint overlapping the second magnetic field sensor unit; and The first coil and the second coil are connected in series.

13. The magnetic position sensor of claim 11 , wherein the first coil surrounds a first core region and the second coil surrounds a second core region; and The first magnetic field sensor unit overlaps with the first core region, and the second magnetic field sensor unit overlaps with the second core region. 14 . The magnetic position sensor of claim 11 , wherein the first magnetic field sensor unit overlaps the first coil, and the second magnetic field sensor unit overlaps the second coil.

15. The magnetic position sensor of claim 10, further comprising: a third magnetic field sensor unit having a third sensor output; as well as a fourth magnetic field sensor unit having a third sensor output; wherein the one or more coils further comprise: a third coil having a third footprint overlapping the third magnetic field sensor unit; and a fourth coil having a fourth footprint overlapping the fourth magnetic field sensor unit; and The first coil, the second coil, the third coil and the fourth coil are connected in series. 16 . The magnetic position sensor of claim 1 , wherein the first and second magnetic field sensor units are on opposite sides of a semiconductor die, and the one or more coils are on the semiconductor die.

17. The magnetic position sensor of claim 1 wherein each of the first magnetic field sensor and the second magnetic field sensor comprises an in-plane Hall effect element.

18. The magnetic position sensor of claim 1 wherein each of the first magnetic field sensor and the second magnetic field sensor comprises an out-of-plane Hall effect element.

19. The magnetic position sensor of claim 1 wherein the first magnetic field sensor comprises an in-plane Hall effect element and the second magnetic field sensor comprises an out-of-plane Hall effect element.

20. A sensor device comprising: Semiconductor die; a first magnetic field sensor unit having a first sensor output on a first side of the semiconductor die; a second magnetic field sensor unit having a second sensor output on a second side of the semiconductor die opposite the first side; one or more coils having one or more footprints overlapping the first magnetic field sensor unit and the second magnetic field sensor unit; as well as A processing circuit having a first sensor input coupled to the first sensor output, a second sensor input coupled to the second sensor output, a current terminal coupled to the one or more coils, and a processing output.

21. The sensor device of claim 20, wherein the one or more coils comprise: a first coil having a first footprint overlapping the first magnetic field sensor unit; as well as a second coil having a second footprint overlapping the second magnetic field sensor unit, The first coil and the second coil are connected in series. 22 . The sensor device of claim 20 , wherein the one or more coils overlap at least a portion of the first magnetic field sensor unit or the second magnetic field sensor unit. 23 . The sensor device of claim 20 , wherein the one or more coils surround one or more core regions, and the first magnetic field sensor unit and the second magnetic field sensor unit overlap the one or more core regions.

24. A method comprising: providing a calibration current to one or more coils having one or more footprints overlapping with a first magnetic field sensor unit and a second magnetic field sensor unit of the sensor device; receiving a first sensor signal from the first magnetic field sensor unit, the first sensor signal representing one or more calibration magnetic fields provided by the one or more coils in response to the calibration current and a second magnetic field; receiving a second sensor signal from the second magnetic field sensor unit, the second sensor signal being representative of the one or more calibration magnetic fields and a third magnetic field; extracting first measurements of the one or more calibration magnetic fields and second measurements of the second magnetic field from the first sensor signal; extracting third measurements of the one or more calibration magnetic fields and a fourth measurement of the third magnetic field from the second sensor signal; as well as A signal representative of a position is provided at a position output based on the first measurement, the second measurement, the third measurement, and the fourth measurement.

25. The method according to claim 24, further comprising: determining one or more gains of the first magnetic field sensor unit and the second magnetic field sensor unit based on the first sensor signal and the second sensor signal; generating a first intermediate signal based on the first sensor signal and the one or more gains; generating a second intermediate signal based on the second sensor signal and the one or more gains; extracting third measurements of the second magnetic field and the third magnetic field based on combining the first intermediate signal and the second intermediate signal; and The signal is provided based on the third measurement value.

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