Angle sensor bridges including star-connected magnetoresistive elements

An angle sensor may comprise a sensing element including a first half bridge, where magnetic reference directions of resistors of the first half bridge are along a first reference axis. The sensing element may include a second half bridge, where magnetic reference directions of resistors of the second half bridge are along a second reference axis. The sensing element may include a third half bridge, where magnetic reference directions of resistors of the third half bridge are along a third reference axis. At least two of the first reference axis, the second reference axis, or the third reference axis may be non-orthogonal to each other.

BACKGROUND

A magnetic angle sensor may be used to determine an orientation of a magnetic field (e.g., an angle between zero degrees and three hundred and sixty degrees) produced by a magnet. The magnetic angle sensor may be a Hall-effect sensor, a magnetoresistive (MR)-based sensor, a variable reluctance sensor (VRS), a fluxgate sensor, or the like.

SUMMARY

According to some possible implementations, an angle sensor may comprise a sensing element including a first half bridge, associated with a first reference axis, that includes a first resistor and a second resistor, where a magnetic reference direction of the first resistor is opposite from a magnetic reference direction of the second resistor, where the magnetic reference direction of the first resistor and the magnetic reference direction of the second resistor are along the first reference axis; a second half bridge, associated with a second reference axis, that includes a third resistor and a fourth resistor, where a magnetic reference direction of the third resistor is opposite from a magnetic reference direction of the fourth resistor, where the magnetic reference direction of the third resistor and the magnetic reference direction of the fourth resistor are along the second reference axis; and a third half bridge, associated with a third reference axis, that includes a fifth resistor and a sixth resistor, where a magnetic reference direction of the fifth resistor is opposite from a magnetic reference direction of the sixth resistor, where the magnetic reference direction of the fifth resistor and the magnetic reference direction of the sixth resistor are along the third reference axis, and where at least two of the first reference axis, the second reference axis, or the third reference axis are non-orthogonal to each other.

According to some possible implementations, an apparatus, may include a sensing element to: provide a first voltage signal, a second voltage signal, and a third voltage signal, the sensing element including a set of MR elements arranged with respect to a first reference axis, a second reference axis, and a third reference axis, the set of MR elements including a first half bridge associated with the first reference axis, a second half bridge associated with the second reference axis, and a third half bridge associated with the third reference axis, and at least one of the first reference axis, the second reference axis, or the third reference axis is non-orthogonal to at least one other of the first reference axis, the second reference axis, and the third reference axis; and a processor to: receive the first voltage signal, the second voltage signal, and the third voltage signal; and determine, based on the first voltage signal, the second voltage signal, and the third voltage signal, an angle of rotation of a magnetic field applied to the sensing element.

According to some possible implementations, a magnetic sensor may include: a sensing element to provide a first output signal, a second output signal, and a third output signal, the sensing element including: at least two MR elements with magnetic reference directions along a first reference axis, at least two MR elements with magnetic reference directions along a second reference axis, and at least two MR elements having magnetic reference directions along a third reference axis, where at least one of the first reference axis, the second reference axis, or the third reference axis is non-orthogonal to at least one other of the first reference axis, the second reference axis, and the third reference axis; and a processor to perform a functional safety check, associated with the magnetic sensor, based on the first output signal, the second output signal, and the third output signal.

DETAILED DESCRIPTION

A magnetic angle sensor, such as an MR-based angle sensor, may include two sensing elements (e.g., a pair of Wheatstone bridges) that are arranged to provide output signals corresponding to two orthogonal components of a magnetic field (parallel to active surfaces of the sensing elements), such as a y-component of the magnetic field and an x-component of the magnetic field. The angle sensor may provide these output signals (e.g., a voltage signal Vyand a voltage signal Vx), and an angle of rotation (α) of a magnet that generates the magnetic field (and an angle of rotation of a rotatable object to which the magnetic is connected) may be calculated based on the output signals corresponding to the two orthogonal components (e.g., α=arctan(Vy/Vx)).

In some cases, a functional safety check may be implemented in the angle sensor. For example, a vector length associated with the output signals (e.g., a vector length equal to Vx2+Vy2) may be monitored during operation of the angle sensor as a functional safety check. In this example, if the vector length remains substantially constant during operation of the angle sensor (e.g., after calibration and/or temperature compensation), then safe operation of the angle sensor may be assumed. However, such a functional safety check (e.g., based on two output signals) has limited accuracy and/or may have insufficient diagnostic coverage due to being dependent on absolute values of the output signals.

In some cases, functional safety may be improved by including another sensing element in the angle sensor, where the other sensing element is arranged to provide an output signal corresponding to another component of the magnetic field (e.g., a component of the magnetic field that is non-orthogonal to the x-component and the y-component, such as a component at a 45 degree angle from both the x-component and the y-component). However, addition of the other sensing element increases cost, complexity, and size of the angle sensor.

Implementations described herein provide an angle sensor with a sensing element that provides output signals associated with multiple (e.g., three or more) components of a magnetic field, where at least one of the multiple components of the magnetic field is non-orthogonal to one or more (e.g., each) other of the multiple components of the magnetic field. The output signals, associated with the multiple components, may be used to determine the angle of rotation, and may allow for improved and/or additional functional safety checks, increased reliability, diversity, and/or redundancy (e.g., as compared to an angle sensor without such a sensing element). Moreover, the sensing element of the angle sensor includes fewer elements (e.g., resistors, connections, or the like) than the angle sensor described above, thereby reducing cost and/or complexity of the angle sensor while providing improved functional safety.

FIG. 1is a diagram of an overview of an example implementation100described herein. As shown inFIG. 1, a magnet (e.g., mechanically connected to a rotatable object) may rotate about an axis (e.g., an axis through a center of the magnet) and produce a rotating magnetic field (B). As shown, an angle sensor, associated with measuring an angle of rotation (α) of the magnet, may include a sensing element arranged to sense N (N>2) components of the magnetic field (e.g., B1through BN). At least one component of the N components of the magnetic field is non-orthogonal (e.g., at an angle greater than or less than 90 degrees) to each of the other components of the N components. In some implementations, each of the N components may be non-orthogonal to each of the other N components. Additionally, or alternatively, the N components may be evenly spaced over a 360 degree rotation with respect to an active surface of the sensing element. Additional details regarding examples of such sensing elements are described below.

As shown, the sensing element may provide output signals (e.g., voltage signals V1through VN) corresponding to the components of the magnetic field B1through BN. As further shown, the angle sensor may determine the angle of rotation based on the output signals.

As further shown, the angle sensor may also perform one or more functional safety checks based on the output signals. For example, a sum associated with the output signals (e.g., V1+V2+ . . . +VN) may be monitored during operation of the angle sensor as a functional safety check. As another example, a vector length associated with the output signals (e.g., V12+V22+VN2) may be monitored during operation of the angle sensor as a functional safety check. As another example, the angle sensor may determine N different angles of rotation (e.g., α1, α2, . . . , αN) based on the output signals, and may compare the N different angles of rotation as a functional safety check. Such functional safety checks (e.g., based on N output signals) have improved accuracy and/or improved diagnostic coverage as compared to those associated with an angle sensor that does not include the sensing element described with regard toFIG. 1. Moreover, the angle sensor, by providing the N output signals, may perform additional functional safety checks and achieve increased reliability, diversity, and/or redundancy, while reducing size, cost and/or complexity (e.g., as compared to an angle sensor without the sensing element described with regard toFIG. 1).

FIG. 2is a diagram of an example environment200in which apparatuses described herein may be implemented. As shown inFIG. 2, environment200may include a magnet210that may rotate about an axis215, an angle sensor220, and a controller230.

Magnet210may include one or more magnets positioned to rotate about axis215(e.g., an imaginary line). In some implementations, magnet210may be connected (e.g., mechanically) to a rotatable object (not shown) such that a rotation angle of magnet210corresponds to a rotation angle of the rotatable object (e.g., when there exists a non-slip relation between an end face of the rotatable object and magnet210).

In the example environment200shown inFIG. 2, magnet210comprises a first half forming a north pole (N) and a second half forming a south pole (S), so that magnet210comprises one pole pair. In some implementations, magnet210may, without limitation, comprise more than one pole pair. In some implementations, magnet210may include a disk magnet that is positioned concentrically about axis215that passes through the center of magnet210, as shown inFIG. 2. While magnet210is shown as circular inFIG. 2, magnet210may be another shape, such as a square, a rectangular, an ellipse, or the like. For example, magnet210may be of an elliptical shape in an instance where an angle between a plane corresponding to a surface of magnet210and axis215deviates from a substantially perpendicular relation. The plane may include a plane symmetrically cutting through magnet210and including a magnet center of magnet210. In practical cases, the plane may be substantially perpendicular to axis215. As another example, magnet210may include a ring magnet that is positioned to rotate about axis215(along with the rotatable object). A ring magnet may be of interest for an arrangement of magnet210at an end of the rotatable object.

In some implementations, magnet210may include two alternating poles on at least two portions of magnet210. For example, magnet210may include a diametrally magnetized magnet with a north pole on a first half of magnet210and a south pole on a second half of magnet210, as shown inFIG. 2. As another example, magnet210may include an axially magnetized magnet with a first north pole and a first south pole stacked on a first half of magnet210, and a second south pole and a second north pole stacked on a second half of magnet210(not shown).

Additionally, or alternatively, magnet210may include a dipole magnet (e.g., a dipole bar magnet, a circular dipole magnet, an elliptical dipole magnet, etc.), a permanent magnet, an electromagnet, a magnetic tape, or the like. Magnet210may be comprised of a ferromagnetic material (e.g., Hard Ferrite), and may produce a magnetic field. Magnet210may further comprise a rare earth magnet which may be of advantage due to an intrinsically high magnetic field strength of rare earth magnets. As described above, in some implementations, magnet210may be attached to or coupled with a rotatable object for which a rotation angle may be determined (e.g., by angle sensor220, by controller230) based on a rotation angle of magnet210.

Angle sensor220may include one or more apparatuses for sensing components of a magnetic field for use in determining an angle of rotation (e.g., of magnet210, of a rotatable object to which magnet210is connected, etc.). For example, angle sensor220may include one or more circuits (e.g., one or more integrated circuits). In some implementations, angle sensor220may be placed at a position relative to magnet210such that angle sensor220may detect components of the magnetic field produced by magnet210. In some implementations, angle sensor220may include an integrated circuit that includes an integrated controller230(e.g., such that an output of angle sensor220may include information that describes a rotation angle of magnet210and/or the rotatable object). In some implementations, angle sensor220may include a sensing element configured to sense components of the magnetic field, produced by magnet210, that are present at angle sensor220. Additional details regarding angle sensor220are described below with regard toFIG. 3.

Controller230may include one or more circuits associated with determining a rotation angle of magnet210, and providing information associated with the rotation angle of magnet210and hence the rotation angle of the rotatable object to which magnet210is connected. For example, controller230may include one or more circuits (e.g., an integrated circuit, a control circuit, a feedback circuit, etc.). Controller230may receive input signals from one or more sensors, such as one or more angle sensors220, may process the input signals (e.g., using an analog signal processor, a digital signal processor, etc.) to generate an output signal, and may provide the output signal to one or more other devices or systems. For example, controller230may receive one or more input signals from angle sensor220, and may use the one or more input signals to generate an output signal comprising the angular position of magnet210and/or the rotatable object to which magnet210is connected.

The number and arrangement of apparatuses shown inFIG. 2are provided as an example. In practice, there may be additional apparatuses, fewer apparatuses, different apparatuses, or differently arranged apparatuses than those shown inFIG. 2. Furthermore, two or more apparatuses shown inFIG. 2may be implemented within a single apparatus, or a single apparatus shown inFIG. 2may be implemented as multiple, distributed apparatuses. Additionally, or alternatively, a set of apparatuses (e.g., one or more apparatuses) of environment200may perform one or more functions described as being performed by another set of apparatuses of environment200.

FIG. 3is a diagram of example elements of angle sensor220included in example environment200ofFIG. 2. As shown, angle sensor220may include a sensing element310, an analog-to-digital convertor (ADC)320, a digital signal processor (DSP)330, an optional memory element340, and a digital interface350.

Sensing element310may include an element for sensing one or more components of a magnetic field present at angle sensor220(e.g., the magnetic field generated by magnet210). For example, sensing element310may include a MR-based sensing element, elements of which are comprised of a magnetoresistive material (e.g., nickel-iron (NiFe)), where the electrical resistance of the magnetoresistive material may depend on a strength and/or a direction of the magnetic field present at the magnetoresistive material. Here, sensing element310may operate based on an anisotropic magnetoresistance (AMR) effect, a giant magnetoresistance (GMR) effect, a tunnel magnetoresistance (TMR) effect, or the like. As another example, sensing element310may include a Hall-based sensing element that operates based on a Hall-effect. As an additional example, sensing element310may include a variable reluctance (VR) based sensing element that operates based on induction. In some implementations, angle sensor220may include multiple sensing elements310. Additional details regarding sensing element310are described below.

ADC320may include an analog-to-digital converter that converts an analog signal from the set of sensing elements310to a digital signal. For example, ADC320may convert analog signals, received from the set of sensing elements310, into digital signals to be processed by DSP330. ADC320may provide the digital signals to DSP330. In some implementations, angle sensor220may include one or more ADCs320.

DSP330may include a digital signal processing device or a collection of digital signal processing devices. In some implementations, DSP330may receive digital signals from ADC320and may process the digital signals to form output signals (e.g., destined for controller230as shown inFIG. 2), such as output signals associated with determining the rotation angle of magnet210rotating with a rotatable object.

Optional memory element340may include a read only memory (ROM) (e.g., an EEPROM), a random access memory (RAM), and/or another type of dynamic or static storage device (e.g., a flash memory, a magnetic memory, an optical memory, etc.) that stores information and/or instructions for use by angle sensor220. In some implementations, optional memory element340may store information associated with processing performed by DSP330. Additionally, or alternatively, optional memory element340may store configurational values or parameters for the set of sensing elements310and/or information for one or more other elements of angle sensor220, such as ADC320or digital interface350.

Digital interface350may include an interface via which angle sensor220may receive and/or provide information from and/or to another device, such as controller230(seeFIG. 2). For example, digital interface350may provide the output signal, determined by DSP330, to controller230and may further receive information from the controller230.

The number and arrangement of elements shown inFIG. 3are provided as an example. In practice, angle sensor220may include additional elements, fewer elements, different elements, or differently arranged elements than those shown inFIG. 3. Additionally, or alternatively, a set of elements (e.g., one or more elements) of angle sensor220may perform one or more functions described as being performed by another set of elements of angle sensor220.

FIGS. 4A-4Eare diagrams associated with an example implementation of sensing element310included in angle sensor220.FIGS. 4A-4Cshow an example bridge400of sensing element310in angle sensor220. As shown inFIGS. 4A-4C, in some implementations, bridge400may include resistors410-1through410-6.

Bridge400includes one or more circuits that provide output signals based on a direction (e.g., an angle) of a magnetic field applied to bridge400. In some implementations, example bridge400may be coupled to a power supply in order to receive an input voltage signal (identified as VbiasinFIGS. 4A-4C). In some implementations, bridge400may be further coupled to a ground (not shown). As described in further detail below, output signals (e.g., voltages, output signals, output voltages, output voltage signals, or the like) provided by bridge400may be used to determine the angle of rotation of magnet210and/or to perform one or more functional safety checks associated with angle sensor220.

Resistor410may include a resistor, such as an MR-based resistor, with an electrical resistance that depends on an angle of an in-plane component of a magnetic field applied to resistor410(i.e., a component of the magnetic field that is parallel to an active surface of resistor410). The angle of the magnetic field may form an angle with respect to a magnetic reference direction associated with resistor410.

In some implementations, as shown inFIGS. 4A-4C, resistors410-1,410-2, and410-3may connected to form a first group of resistors410, while resistors410-4,410-5, and410-6may connected to form a second group of resistors410. In some aspects, each group of resistors410(e.g., each group of three resistors410, each half bridge of resistors410, and/or the like) may be connected to an individual power supply in order to further improve functional safety of angle sensor200. As shown, each group of resistors410may be arranged such that magnetic reference directions of resistors410in each group are angularly separated. For example, resistors410-1,410-2, and410-3may be arranged such that magnetic reference directions of resistors410-1,410-2, and410-3are angularly separated by approximately 120 degrees. As another example, resistors410-4,410-5, and410-6may be arranged such that magnetic reference directions of resistors410-4,410-5, and410-6are angularly separated by approximately 120 degrees. In some implementations, as shown inFIGS. 4A-4C, a group of resistors410may be arranged with equal angular separation of the magnetic reference directions of resistors410included in the group of resistors410.

Additionally, or alternatively, a group of resistors410may be arranged such that angular separation of the magnetic reference directions of resistors410is not equal. For example, a magnetic reference direction of a first resistor410may be angularly separated from a magnetic reference direction of a second resistor410by a first amount (e.g., 140 degrees), while the magnetic reference direction of the second resistor410may be angularly separated from a magnetic reference direction of a third resistor410by a second amount (e.g., 100 degrees), and the magnetic reference direction of the third resistor410may be angularly separated from a magnetic reference direction of the first resistor410by a third amount (e.g., 120 degrees).

In some implementations, a group of resistors410may be arranged such that a magnetic reference direction of at least one resistor410is non-orthogonal to a magnetic reference direction of each other resistor in the group of resistors. Additionally, or alternatively, a subset of a group of resistors410may be arranged such that magnetic reference directions of the subset of resistors410are orthogonal. Here, another resistor410, not included in the subset of resistors410, may be arranged such that a magnetic reference direction of the other resistor410is non-orthogonal to the magnetic reference directions of the subset of resistors410.

As further shown inFIGS. 4A-4C, a given resistor410, included in the first group of resistors410, may be arranged such that the magnetic reference direction of the given resistor410opposes (e.g., is angularly separated by approximately 180 degrees) a magnetic reference direction of a corresponding resistor410included in the second group of resistors410. For example, as shown, resistors410-1and410-4are arranged such that magnetic reference directions of resistors410-1and410-4are opposing. Similarly, resistors410-2and410-5are arranged such that magnetic reference directions of resistors410-2and410-5are opposing. As further shown, resistors410-3and410-6are arranged such that magnetic reference directions of resistors410-3and410-6are opposing.

Resistances of resistors410-1through410-6as function of the angle of rotation are described by the following equations:
R410-1=R×(O+cos(α))
R410-2=R×(O+cos(α+2π/3))
R410-3=R×(O+cos(α+4π/3))
R410-4=R×(O−cos(α))
R410-5=R×(O−cos(α+2π/3))
R410-6=R×(O−cos(α+4π/3))
where R represents a maximum resistance of each resistor410, and O represents an angular offset associated with positioning of bridge400.

In some implementations, during operation, bridge400may provide multiple output signals associated with components of a magnetic field applied to bridge400, where at least one component, of the components of the magnetic field, is non-orthogonal to each of the other components of the magnetic field. In some implementations, bridge400may provide the multiple output signals based on selectively connecting (i.e., switching) resistors410to different voltage terminals during operation of angle sensor220in order to form different bridge configurations.

For example, as shown inFIG. 4A, a first bridge configuration may be formed at a first time during operation by connecting resistors410-1and410-4to a first voltage terminal (e.g., the upper Vbiasterminal as shown inFIG. 4A) and connecting resistors410-2,410-3,410-5, and410-6to a second voltage terminal (e.g., the lower Vbiasterminal as shown inFIG. 4A). Here, as shown inFIG. 4A, bridge400may output a first voltage signal (V1) associated with the first bridge configuration. An amplitude of V1depends on a resistance of the first bridge configuration. The resistance of the first bridge configuration is described by the following equation:

R1=Rp⁡(R410-2,R410-3)R410-1+Rp⁡(R410-2,R410-3)⁢Rp⁡(R410-5,R410-6)R410-4+Rp⁡(R410-5,R410-6)
where Rp(R410-2, R410-3) and Rp(R410-5, R410-6) represent equivalent resistances of parallel resistors410-2and410-3and parallel resistors410-5and410-6, respectively, described by the following equations:

Continuing with this example, as shown inFIG. 4B, a second bridge configuration may be formed at a second time during operation (e.g., immediately following the first time) by switching connections of resistors410such that resistors410-2and410-5are connected to the first voltage terminal and resistors410-1,410-3,410-4, and410-6are connected to the second voltage terminal. Here, as shown inFIG. 4B, bridge400may output a second voltage signal (V2) associated with the second bridge configuration. An amplitude of V2depends on a resistance of the second bridge configuration. The resistance of the second bridge configuration is described by the following equation:

R2=Rp⁡(R410-3,R410-1)R410-2+Rp⁡(R410-3,R410-1)⁢Rp⁡(R410-6,R410-4)R410-5+Rp⁡(R410-6,R410-4)
where Rp(R410-3, R410-1) and Rp(R410-6, R410-4) represent equivalent resistances of parallel resistors410-1and410-3and parallel resistors410-4and410-6, respectively, described by the following equations:

Continuing with this example, as shown inFIG. 4C, a third bridge configuration may be formed at a third time during operation (e.g., immediately following the second time) by switching connections of resistors410such that resistors410-3and410-6are connected to the first voltage terminal and resistors410-1,410-2,410-4, and410-5are connected to the second voltage terminal. Here, as shown inFIG. 4C, bridge400may output a third voltage signal (V3) associated with the third bridge configuration. An amplitude of V3depends on a resistance of the third bridge configuration. The resistance of the third bridge configuration is described by the following equation:

R3=Rp⁡(R410-1,R410-2)R410-3+Rp⁡(R410-1,R410-2)⁢Rp⁡(R410-4,R410-5)R410-6+Rp⁡(R410-4,R410-5)
where Rp(R410-1, R410-2) and Rp(R410-4, R410-5) represent equivalent resistances of parallel resistors410-1and410-2and parallel resistors410-4and410-5, respectively, described by the following equations:

FIG. 4Dis a diagram of an example graphical representation showing resistance of each bridge configuration of bridge400with respect to the angle of rotation. Notably, as shown inFIG. 4D, for a given angle of rotation, a sum of the resistances corresponding to each bridge configuration is approximately equal to zero (e.g., for a given value of R and O).

In some implementations, angle sensor220may determine the angle of rotation and/or perform one or more improved functional safety checks based on the first voltage signal, the second voltage signal, and the third voltage signal.FIG. 4Eshows a diagram associated with determination of the angle of rotation based on the output signals provided by bridge400. As shown inFIG. 4E, in some implementations, angle sensor220may determine the angle of rotation based on reference axes corresponding to magnetic reference directions of resistors410.

For example, as shown, a sine component of the magnetic field, with respect to a first reference axis (e.g., an axis corresponding to the magnetic reference direction of resistors410-1and410-4), is represented by V1, while a cosine component of the magnetic field, with respect to the first reference axis, is represented by a combination of V2and V3(e.g., (V2−V3)/(2×cos(30°)). Similarly, a sine component of the magnetic field, with respect to a second reference axis (e.g., an axis corresponding to the magnetic reference direction of resistors410-2and410-5, representing a 120° clockwise rotation from the first reference axis), is represented by V2, while a cosine component of the magnetic field, with respect to the second reference axis, is represented by a combination of V3and V1(e.g., (V3−V1)/(2×cos(30°)). Further, in this example, a sine component of the magnetic field, with respect to a third reference axis (e.g., an axis corresponding to the magnetic reference direction of resistors410-3and410-6, representing a 240° clockwise rotation from the first reference axis), is represented by V3, while a cosine component of the magnetic field, with respect to the third reference axis, is represented by a combination of V1and V2(e.g., (V1−V2)/(2×cos(30°)).

As further shown inFIG. 4E, angle sensor220may determine the angle of rotation based on the sine components and the cosine components associated with each reference axis (e.g., based on inverse tangents of each sine component divided by a corresponding cosine component, and correcting for the rotation of the reference axis).

In some implementations, angle sensor220may perform one or more improved functional safety checks using the output signals and/or the determined angle of rotation. For example, since a sum of resistances of each bridge configuration should be approximately equal to zero for a given angle of rotation (as shown above with regard toFIG. 4D), a sum of the output signals should also be approximately equal to zero (e.g., V1+V2+V3=0). Here, angle sensor220may determine whether the sum of the output signals is approximately equal to zero (e.g., within a threshold amount, such as 0.1 volts, 0.05 volts, or the like). If so, then safe operation of angle sensor220may be assumed. Conversely, if the sum of the output signals is not approximately equal to zero (e.g., differs from zero by an amount equal to or greater than the threshold amount), then angle sensor220may determine that one or more elements of bridge400are not operating properly, and may act accordingly (e.g., send a warning message and/or notification to controller230, raise an error flag, disable bridge400, or the like).

As another example, the arrangement of bridge400should result in a vector sum of the output signals being substantially constant during operation (e.g., V12+V22+V32=constant). Here, angle sensor220may determine whether the vector sum of the output signals is substantially constant (e.g., whether the vector sum varies at a rate that satisfies threshold). If so, then safe operation of angle sensor220may be assumed. Conversely, if the vector sum of the output signals is not substantially constant (e.g., varying at a rate that is greater than the threshold), then angle sensor220may determine that one or more elements of bridge400are not operating properly, and may act accordingly (e.g., send a warning message to controller230, raise an error flag, disable bridge400, or the like).

As another example, the arrangement of bridge400should result in each determined angle of rotation (e.g., α1, α2, and α3inFIG. 4E) substantially matching. Here, angle sensor220may determine whether each determined angle of rotation substantially matches (e.g., whether differences between each of α1, α2, and α3are less than or equal to a threshold difference, such as 0.1 degrees, 0.5 degrees, or the like). If so, then safe operation of angle sensor220may be assumed. Conversely, if the determined angles of rotation do not substantially match (e.g., if a difference greater than the threshold), then angle sensor220may determine that one or more elements of bridge400are not operating properly, and may act accordingly (e.g., send a warning message and/or notification to controller230, raise an error flag, disable bridge400, or the like).

In some implementations, when two or more determined angles of rotation substantially match, and a third determined angle does not, then angle sensor220may identify which determined angle of rotation does not match, and act accordingly. For example, if α1substantially matches α2, and α3does not substantially match α1or α2, then angle sensor220may continue determining α1or α2, discontinue determining α3, and send a warning message and/or notification, raise an error flag, or the like, regarding a possible error or malfunction associated with determining α3.

In some implementations, angle sensor220may perform one or more functional safety checks before determining the angle of rotation in order to conserve processing resources, reduce power consumption, or the like. For example, angle sensor220may determine whether the sum of the output signals is approximately equal to zero before determining the angle(s) of rotation. Here, if the sum of the output signals is not approximately equal to zero, as described above, then angle sensor220may refrain from determining the angle of rotation (e.g., since safe operation may not be assumed), thereby conserving processing resources, reducing power consumption, or the like.

In this way, angle sensor220may provide output signals associated with three or more components of a magnetic field, where at least one of the three or more components of the magnetic field is non-orthogonal to each other component of the magnetic field. The output signals, associated with the multiple components, may be used to determine the angle of rotation, and may allow for improved and/or additional functional safety checks, increased reliability, diversity, and/or redundancy (e.g., as compared to an angle sensor without the sensing element of angle sensor220). Moreover, the sensing element of angle sensor220includes only six resistors410, thereby reducing cost and/or complexity of angle sensor220while providing improved functional safety.

The number and arrangement of resistors410shown inFIGS. 4A-4C, and the examples shown inFIGS. 4D and 4Eare provided merely as examples. In practice, sensing element310may include additional resistors410, fewer resistors410, different resistors410, or differently arranged resistors410than those shown inFIGS. 4A-4C. Additionally, angular separations, orientations of magnetic reference directions, equations for determining the angle of rotation, resistance values, or the like, associated withFIGS. 4A-4Eare provided merely as examples, and other examples are possible.

FIGS. 5A-5Dare diagrams associated with another example implementation of sensing element310included in angle sensor220.FIGS. 5A-5Cshow an example bridge500of sensing elements310in angle sensor220. As shown inFIGS. 5A-5C, in some implementations, bridge500may include resistors410-1through410-6. Bridge500and resistors410may be arranged in a manner similar to that described above with regard to bridge400.

In some implementations, during operation, bridge500may provide multiple output signals associated with components of a magnetic field applied to bridge500, where at least one component, of the components of the magnetic field, is non-orthogonal to each of the other components of the magnetic field. In some implementations, bridge500may provide the multiple output signals based on selectively connecting (i.e., switching) resistors410to different voltage terminals during operation of angle sensor220in order to form different bridge configurations or disconnecting resistors410from all voltage terminals during operation.

For example, as shown inFIG. 5A, a first bridge configuration may be formed at a first time during operation by connecting resistors410-1and410-4to a first voltage terminal (e.g., the upper Vbiasterminal as shown inFIG. 5A), connecting resistors410-2and410-5to a second voltage terminal (e.g., the lower Vbiasterminal as shown inFIG. 5A), and disconnecting resistors410-3and410-6from both voltage terminals. Here, as shown inFIG. 5A, bridge500may output a first voltage signal (V1) associated with the first bridge configuration. An amplitude of V1depends on a resistance of the first bridge configuration. The resistance of the first bridge configuration is described by the following equation:

Continuing with this example, as shown inFIG. 5B, a second bridge configuration may be formed at a second time during operation (e.g., immediately following the first time) by connecting resistors410-2and410-5to the first voltage terminal, connecting resistors410-3and410-6to the second voltage terminal, and disconnecting resistors410-1and410-4from both voltage terminals. Here, as shown inFIG. 5B, bridge500may output a second voltage signal (V2) associated with the second bridge configuration. An amplitude of V2depends on a resistance of the second bridge configuration. The resistance of the second bridge configuration is described by the following equation:

Continuing with this example, as shown inFIG. 5C, a third bridge configuration may be formed at a third time during operation (e.g., immediately following the second time) by connecting resistors410-3and410-6to the first voltage terminal, connecting resistors410-1and410-4to the second voltage terminal, and disconnecting resistors410-2and410-5from both voltage terminals. Here, as shown inFIG. 5C, bridge500may output a third voltage signal (V3) associated with the third bridge configuration. An amplitude of V3depends on a resistance of the third bridge configuration. The resistance of the third bridge configuration is described by the following equation:

FIG. 5Dis a diagram of an example graphical representation showing resistance of each bridge configuration of bridge500with respect to the angle of rotation. Notably, as shown inFIG. 5D, for a given angle of rotation, a sum the resistances corresponding to each bridge configuration is approximately equal to zero (e.g., for a given value of R and O).

In some implementations, angle sensor220may determine the angle of rotation based on the first voltage signal, the second voltage signal, and the third voltage signal. For example, angle sensor220may determine the angle of rotation based on the following equations (similar to those described in association withFIG. 4E, and accounting for a 30° shifted angle axis):
α1=arctan[2×cos(30°)×V1/(V2−V3)]−30°
α2=arctan[2×cos(30°)×V2/(V3−V1)]−150°
α3=arctan[2×cos(30°)×V3/(V1−V2)]−270°

In some implementations, angle sensor220may perform one or more improved functional safety checks associated with bridge500, in a manner similar to that described above with regard to bridge400.

The number and arrangement of resistors510shown inFIGS. 5A-5C, and the example shown inFIG. 5Dare provided merely as examples. In practice, sensing element310may include additional resistors410, fewer resistors410, different resistors410, or differently arranged resistors410than those shown inFIGS. 5A-5C. Additionally, angular separations, orientations of magnetic reference directions, equations for determining the angle of rotation, resistance values, or the like, associated withFIGS. 5A-5Dare provided merely as examples, and other examples are possible.

FIGS. 6A and 6Bare diagrams associated with an additional example implementation of sensing element310included in angle sensor220.FIG. 6Ashows an example bridge600of sensing element310in angle sensor220. As shown inFIG. 6, in some implementations, bridge600may include resistors410-1through410-6.

In some implementations, as shown inFIG. 6A, resistors410-1through410-6may be arranged to form three non-orthogonal half bridges. For example, resistor410-1and410-4may be arranged to form a first half bridge associated with a first reference axis (e.g., a 0° angle with respect to a vertical direction ofFIG. 6B), resistor410-2and410-5may be arranged to form a second half bridge associated with a second reference axis (e.g., a 120° clockwise angle of rotation with respect to a vertical direction ofFIG. 6B), and resistor410-3and410-6may be arranged to form a third half bridge associated with a third reference axis (e.g., a 240° clockwise angle of rotation with respect to a vertical direction ofFIG. 6B). As shown, in some implementations, the first, second, and third half bridges may be connected to the first and second voltage terminals. In some implementations, the first, second, and third half bridges may be permanently connected to the first and second voltage terminals.

In some implementations, during operation, bridge600may concurrently provide multiple output signals associated with components of a magnetic field applied to bridge600, where at least one component, of the components of the magnetic field, is non-orthogonal to each of the other components of the magnetic field. For example, as shown inFIG. 6A, bridge600may output a first voltage signal (V1) associated with voltage between the first half bridge and the second half bridge. An amplitude of V1depends on an equivalent resistance of the first half bridge and the second half bridge. The equivalent resistance of the first half bridge and the second half bridge is described by the following equation:

Continuing with this example, bridge600may output a second voltage signal (V2) associated with voltage between the second half bridge and the third half bridge. An amplitude of V2depends on an equivalent resistance of the second half bridge and the third half bridge. The equivalent resistance of the second half bridge and the third half bridge is described by the following equation:

Continuing with this example, bridge600may output a third voltage signal (V3) associated with voltage between the third half bridge and the first half bridge. An amplitude of V3depends on an equivalent resistance of the third half bridge and the first half bridge. The equivalent resistance of the third half bridge and the first half bridge is described by the following equation:

FIG. 6Bis a diagram of an example graphical representation showing equivalent resistances of bridge600with respect to the angle of rotation. Notably, as shown inFIG. 6B, for a given angle of rotation, a sum the resistances corresponding to each bridge configuration is approximately equal to zero (e.g., for a given value of R and O). In some implementations, bridge600may have a reduced area consumption with a slight reduction in signal amplitude as compared to a prior angle sensor. For example, bridge600may reduce area consumption by approximately 50% as compared to a prior angle sensor with similar capabilities (e.g., a prior angle sensor with three full Wheatstone bridges), with an amplitude reduction of approximately 12%, as illustrated inFIG. 6B(e.g., by the line labeled “88% of Prior”).

In some implementations, angle sensor220may determine the angle of rotation based on the first voltage signal, the second voltage signal, and the third voltage signal, in a manner similar to the described above with regard to bridge400. Additionally, or alternatively, angle sensor220may perform one or more improved functional safety checks associated with bridge600, in a manner similar to that described above with regard to bridge400.

The number and arrangement of resistors410shown inFIG. 6A, and the example shown inFIG. 6Bare provided merely as examples. In practice, sensing element310may include additional resistors410, fewer resistors410, different resistors410, or differently arranged resistors410than those shown inFIG. 6A. Additionally, angular separations, orientations of magnetic reference directions, equations for determining the angle of rotation, resistance values, or the like, associated withFIGS. 6A and 6Bare provided merely as examples, and other examples are possible.

FIG. 7is a diagram associated with another example implementation of sensing element310included in angle sensor220.FIG. 7shows an example bridge700of sensing element310in angle sensor220. As shown inFIG. 7, in some implementations, bridge700may include two of each of resistors410-1through410-6.

In some implementations, bridge700may operate a manner similar to that of bridge600ofFIG. 6. In some implementations, inclusion of additional resistors410in bridge700may provide for increased reliability and/or redundancy.

The number and arrangement of resistors410shown inFIG. 7are provided merely as an example. In practice, sensing element310may include additional resistors410, fewer resistors410, different resistors410, or differently arranged resistors410than those shown inFIG. 7. Additionally, angular separations, orientations of magnetic reference directions, equations for determining the angle of rotation, resistance values, or the like, associated withFIG. 7are provided merely as examples, and other examples are possible.

FIG. 8is a diagram associated with an additional example implementation of sensing element310included in angle sensor220.FIG. 8shows an example bridge800of sensing element310in angle sensor220. As shown inFIG. 8, in some implementations, bridge800may include resistors410-1through410-10.

In some implementations, as shown inFIG. 8, resistors410-1through410-10may be arranged to form five non-orthogonal half bridges. For example, resistor410-1and410-6may be arranged to form a first half bridge associated with a first reference axis (e.g., a 0° angle with respect to a vertical direction ofFIG. 8), resistor410-2and410-7may be arranged to form a second half bridge associated with a second reference axis (e.g., a 72° clockwise angle of rotation with respect to a vertical direction ofFIG. 8), resistor410-3and410-8may be arranged to form a third half bridge associated with a third reference axis (e.g., a 144° clockwise angle of rotation with respect to a vertical direction ofFIG. 8), resistor410-4and410-9may be arranged to form a fourth half bridge associated with a fourth reference axis (e.g., a 216° clockwise angle of rotation with respect to a vertical direction ofFIG. 8), and resistor410-5and410-10may be arranged to form a fifth half bridge associated with a fifth reference axis (e.g., a 288° clockwise angle of rotation with respect to a vertical direction ofFIG. 8). In some implementations, the first, second, third, fourth, and fifth half bridges may be connected to a respective voltage terminals. In some implementations, the first, second, third, fourth, and fifth half bridges may be permanently and/or directly connected to the first and second voltage terminals.

In some implementations, during operation, bridge800may concurrently provide multiple output signals associated with components of a magnetic field applied to bridge800, where at least one component, of the components of the magnetic field, is non-orthogonal to each of the other components of the magnetic field.

For example, in a first implementation shown inFIG. 8(labeled as differential measurement set1inFIG. 8), bridge800may output a first voltage signal (V1-3) associated with voltage between the first half bridge and the third half bridge, an amplitude of which depends on an equivalent resistance of the first half bridge and the third half bridge. As further shown, bridge800may output a second voltage signal (V3-5) associated with the voltage between the third half bridge and the fifth half bridge, an amplitude of which depends on an equivalent resistance of the third half bridge and the fifth half bridge. As further shown, bridge800may output a third voltage signal (V2-4) associated with the voltage between the second half bridge and the fourth half bridge, an amplitude of which depends on an equivalent resistance of the second half bridge and the fourth half bridge. As further shown, bridge800may output a fourth voltage signal (V4-1) associated with the voltage between the fourth half bridge and the first half bridge, an amplitude of which depends on an equivalent resistance of the fourth half bridge and the first half bridge. As further shown, bridge800may output a fifth voltage signal (V5-2) associated with the voltage between the fifth half bridge and the second half bridge, an amplitude of which depends on an equivalent resistance of the fifth half bridge and the second half bridge.

As another example, in a second implementation shown inFIG. 8(labeled as differential measurement set2inFIG. 8), bridge800may output a first voltage signal (V1-2) associated with voltage between the first half bridge and the second half bridge, an amplitude of which depends on an equivalent resistance of the first half bridge and the second half bridge. As further shown, bridge800may output a second voltage signal (V2-3) associated with the voltage between the second half bridge and the third half bridge, an amplitude of which depends on an equivalent resistance of the second half bridge and the third half bridge. As further shown, bridge800may output a third voltage signal (V3-4) associated with the voltage between the third half bridge and the fourth half bridge, an amplitude of which depends on an equivalent resistance of the third half bridge and the fourth half bridge. As further shown, bridge800may output a fourth voltage signal (V4-5) associated with the voltage between the fourth half bridge and the fifth half bridge, an amplitude of which depends on an equivalent resistance of the fourth half bridge and the fifth half bridge. As further shown, bridge800may output a fifth voltage signal (V5-1) associated with the voltage between the fifth half bridge and the first half bridge, an amplitude of which depends on an equivalent resistance of the fifth half bridge and the first half bridge.

In the above examples, angle sensor220may determine the angle of rotation based on the first voltage signal, the second voltage signal, the third voltage signal, the fourth voltage signal, and the fifth voltage signal, in a manner similar to the described above. Additionally, or alternatively, angle sensor220may perform one or more improved functional safety checks associated with bridge800, in a manner similar to that described above. For example, since a sum of resistances of each bridge configuration should be approximately equal to zero for a given angle of rotation, a sum of the output signals should also be approximately equal to zero (e.g., V1-3+V3-5+V2-4+V4-1+V5-2=0 for differential measurement set1, or V1-2+V2-3+V3-4+V4-5+V5-1=0 for differential measurement set2). Here, angle sensor220may determine whether the sum of the output signals is approximately equal to zero (e.g., within a threshold amount, such as 0.1 volts, 0.05 volts, or the like). If so, then safe operation of angle sensor220may be assumed. Conversely, if the sum of the output signals is not approximately equal to zero (e.g., differs from zero by an amount equal to or greater than the threshold amount), then angle sensor220may determine that one or more elements of bridge800are not operating properly, and may act accordingly (e.g., send a warning message and/or notification to controller230, raise an error flag, disable bridge800, or the like).

As another example, the arrangement of bridge800should result in a vector sum of the output signals being substantially constant during operation (e.g., V1-32+V3-52+V2-42+V4-12+V5-22=constant for differential measurement set1, or V1-22+V2-32+V3-42+V4-52+V5-12=constant for differential measurement set2). Here, angle sensor220may determine whether the vector sum of the output signals is substantially constant. If so, then safe operation of angle sensor220may be assumed. Conversely, if the vector sum of the output signals is not substantially constant (e.g., varying at a rate that is greater than the threshold), then angle sensor220may determine that one or more elements of bridge800are not operating properly, and may act accordingly (e.g., send a warning message to controller230, raise an error flag, disable bridge800, or the like).

The number and arrangement of resistors410shown inFIG. 8are provided merely as examples. In practice, sensing element310may include additional resistors410, fewer resistors410, different resistors410, or differently arranged resistors410than those shown inFIG. 8. Additionally, angular separations, orientations of magnetic reference directions, equations for determining the angle of rotation, resistance values, or the like, associated withFIG. 8are provided merely as examples, and other examples are possible.

Implementations described herein provide an angle sensor with a sensing element that provides output signals associated with multiple (e.g., three or more) components of a magnetic field, where at least one of the multiple components of the magnetic field is non-orthogonal to each other of the multiple components of the magnetic field. The output signals, associated with the multiple components, may be used to determine the angle of rotation, and may allow for improved and/or additional functional safety checks, increased reliability, diversity, and/or redundancy (e.g., as compared to an angle sensor without such a sensing element). Moreover, the sensing element of the angle sensor includes fewer elements (e.g., resistors, connections, or the like) than a prior angle sensor, thereby reducing cost and/or complexity of the angle sensor while providing improved functional safety.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementations to the precise form disclosed. Modifications and variations are possible in light of the above disclosure or may be acquired from practice of the implementations. For example, while the implementations described herein are described in the context of three reference axes and five reference axes, in practice another number of reference axes may be utilized.