Current sensor positioning error correction using auxiliary hall cells

A current sensor may comprise a first Hall cell, a second Hall cell, a third Hall cell, a fourth Hall cell, and a fifth Hall cell to a set of magnetic field values associated with a magnetic field generated by a current passing through a current rail. The second Hall cell may be positioned at a first distance from the first Hall cell, and the third Hall cell may be positioned at a second distance from the first Hall cell such that the third Hall cell is positioned between the first Hall cell and the second Hall cell. The fourth Hall cell may be positioned adjacent to the first Hall cell, and the fifth Hall cell may be positioned at a third distance from the fourth Hall cell. The magnetic field values may be used to determine an amount of current associated with the current passing through the current rail.

BACKGROUND

A magnetic current sensor may determine an amount of current based on sensing a magnetic field, generated by the current, and based on the fact that the generated magnetic field is proportional to the amount of current. Since no galvanic coupling is needed, voltage isolation between a low voltage signal processing circuit and a high voltage current rail is possible up to several kilovolts.

SUMMARY

According to some possible implementations, a magnetic current sensor may comprise: a first primary Hall cell to sense a first magnetic field value, where the first magnetic field value may be associated with a magnetic field generated by a current passing through a current rail; a second primary Hall cell to sense a second magnetic field value, where the second magnetic field value may be associated with the magnetic field generated by the current passing through the current rail, and where the second primary Hall cell may be positioned along an axis at a first distance from the first primary Hall cell, where the axis may be in a direction substantially perpendicular to the current passing through the current rail; and an auxiliary Hall cell to sense a third magnetic field value, where the auxiliary Hall cell may be positioned along the axis at a second distance from the first primary Hall cell, where the second distance may be less than the first distance such that the auxiliary Hall cell is positioned along the axis and between the first primary Hall cell and the second primary Hall cell, and where the first magnetic field value, the second magnetic field value, and the third magnetic field value may be used to determine an amount of current associated with the current passing through the current rail.

According to some possible implementations, a magnetic current sensor, may comprise: a first primary Hall cell to sense a first magnetic field value, where the first magnetic field value may be associated with a magnetic field generated by a current passing through a current rail; a second primary Hall cell to sense a second magnetic field value, where the second magnetic field value may be associated with the magnetic field generated by the current passing through the current rail, and where the second primary Hall cell may be positioned along an axis at a first distance from the first primary Hall cell, where the axis may be in a direction substantially perpendicular to the current passing through the current rail; a first auxiliary Hall cell to sense a third magnetic field value, where the third magnetic field value may be associated with the magnetic field generated by the current passing through the current rail, where the first auxiliary Hall cell may be positioned adjacent to the first primary Hall cell in a direction substantially parallel to a direction of the current; and a second auxiliary Hall cell to sense a fourth magnetic field value, where the fourth magnetic field value may be associated with the magnetic field generated by the current passing through the current rail, where the second auxiliary Hall cell may be positioned along the axis at a second distance from the first auxiliary Hall cell in a direction substantially perpendicular to the current passing through the current rail, and where the first magnetic field value, the second magnetic field value, the third magnetic field value, and the fourth magnetic field value may be used to determine an amount of current associated with the current passing through the current rail.

According to some possible implementations, a method may comprise: sensing, by a first Hall cell included in a current sensor, a first magnetic field value associated with a magnetic field generated by a current passing through a current rail; sensing, by a second Hall cell included in the current sensor, a second magnetic field value associated with the magnetic field generated by the current passing through the current rail, where the second Hall cell may be located on an axis and at a first distance from the first Hall cell, where the axis may be substantially perpendicular to the current and substantially parallel to a face of the current rail; sensing, by a third Hall cell included in the current sensor, a third magnetic field value associated with the magnetic field generated by the current passing through the current rail, where the third Hall cell may be located on the axis and at a second distance from the first Hall cell, where the second distance may be less than the first distance such that the third Hall cell is located on the axis and between the first Hall cell and the second Hall cell; sensing, by a fourth Hall cell included in the current sensor, a fourth magnetic field value associated with the magnetic field generated by the current passing through the current rail, where the fourth Hall cell may be located adjacent to the first Hall cell in a direction substantially parallel to a direction of the current; sensing, by a fifth Hall cell included in the current sensor, a fifth magnetic field value associated with the magnetic field generated by the current passing through the current rail, where the fifth Hall cell may be located on the axis and at a third distance from the fourth Hall cell in a direction substantially perpendicular to the current passing through the current rail; deriving, by the current sensor, a differential Hall signal based on the first magnetic field value and the second magnetic field value; deriving, by the current sensor, a first auxiliary Hall signal based on the third magnetic field value; deriving, by the current sensor, a second auxiliary Hall signal based on the fourth magnetic field value and the fifth magnetic field value; determining, by the current sensor, a corrected differential Hall signal based on the differential Hall signal, the first auxiliary Hall signal, and the second auxiliary Hall signal; and determining, by the current sensor, an amount of current, associated with the current passing through the current rail, based on the corrected differential Hall signal.

DETAILED DESCRIPTION

A differential-Hall based magnetic current sensor may make use of an external current rail (e.g., a trace on a printed circuit board (PCB) plate to which the magnetic current sensor is attached, positioned adjacent to, etc.) in order to determine an amount of current passing through the current rail. The magnetic current sensor may be positioned relative to and attached (e.g., soldered) to the current rail such that two primary Hall cells (e.g., lateral Hall cells included in the magnetic current sensor) are located relative to opposite sides of the current rail (e.g., opposite sides of the center of a symmetric current rail). The primary Hall cells may sense opposite vertical magnetic field values (e.g., associated with a magnetic field generated by the current as the current passes through the current rail) on the opposite sides of the current rail, and may determine the amount of current passing through the current rail based on a vertical differential Hall signal derived from the sensed vertical magnetic field values. However, the vertical differential Hall signal, derived from the vertical magnetic field values, may be sensitive to placement of the magnetic current sensor on the current rail.

For example, if the magnetic current sensor is positioned such that the primary Hall cells are not horizontally equidistant (e.g., in an x-direction on the face of the current rail and substantially perpendicular to the direction of the current) from the center of a symmetric current rail, then the derived vertical differential Hall signal may be affected such that the magnetic current sensor may inaccurately determine the amount of current passing through the current rail. Such a positioning error may be referred to as a horizontal positioning error. In some cases, an assembly process associated with attaching the magnetic current sensor in a position relative to the current rail may allow for a horizontal positioning tolerance (e.g., ±100 micrometers (μm), ±200 μm, etc.) in the x-direction.

As another example, if the magnetic current sensor is positioned such that the primary Hall cells are not vertically separated from the current rail by a known distance (e.g., in a z-direction away from the current rail and substantially perpendicular to the face of the current rail), then the derived vertical differential Hall signal may also be affected such that the magnetic current sensor may inaccurately determine the amount of current passing through the current rail. Such a positioning error may be referred to as a vertical positioning error. In some cases, an assembly process associated with attaching the magnetic current sensor in a position relative to the current rail may allow for a vertical positioning tolerance (e.g., ±65 μm, etc.) in the z-direction. Moreover, vertical positioning error may be introduced after the current sensor is attached to the current rail (e.g., due to swelling).

One technique that may be used to correct the vertical differential Hall signal is to implement End-of-Line (EOL) calibration after the magnetic current sensor is (fixedly) placed relative to the current rail. EOL calibration may include forcing a known current through the current rail in both directions (e.g., in order to cancel potential sensor-offset effects), and calculating a gain correction factor as a ratio of a target vertical differential Hall signal (e.g., known based on the known current) and an actual vertical differential Hall signal (e.g., derived by the magnetic current sensor). The gain correction factor may then be used to adjust a compensation constant (e.g., stored in an Electrically Erasable Programmable Read-Only Memory (EEPROM) in the magnetic current sensor, on a micro-controller configured to process the differential Hall signal, etc.), and the compensation constant may, during application, automatically and continuously be applied to the derived vertical differential Hall signal in order to cancel the differential Hall signal error (e.g., due to horizontal positioning error or due to vertical positioning error) that may otherwise arise. However, implementing such an EOL calibration process may increase a variety of costs associated with the magnetic current sensor (e.g., additional testing time, additional equipment costs, increased production complexity, etc.). Moreover, EOL calibration may be ineffective with respect to correcting vertical positioning error that is introduced at a later time (e.g., due to swelling after the current sensor is installed).

Implementations described herein may provide a magnetic current sensor that includes one or more auxiliary Hall cells (e.g., lateral Hall cells and/or vertical Hall cells), positioned with respect to two primary Hall cells, that may sense magnetic field values, associated with a magnetic field generated by a current passing through a current rail. Information associated with the magnetic field values sensed by the one or more auxiliary Hall cells may then be used to correct a differential Hall signal error that arises due to a horizontal positioning error and/or a vertical positioning error associated with attaching the magnetic current sensor in a position relative to the current rail.

FIGS. 1A-1Dare diagrams of an overview of an example implementation100described herein. For the purposes of example implementation100, assume that a magnetic current sensor is attached in a position relative to a symmetrical current rail (e.g., a current rail with a constant width in a direction perpendicular to the current) that is external to the magnetic current sensor and that has a width w. Further, assume that the magnetic current sensor includes a pair of primary Hall cells (e.g., lateral Hall cells) separated by a particular horizontal distance (e.g., dT).

As shown inFIG. 1A, the magnetic current sensor may be positioned in a position relative to the current rail such that the midpoint of the current rail (e.g., w midpoint) is not aligned with the midpoint of the distance between the pair of primary Hall cells (e.g., dTmidpoint), but within a horizontal positioning tolerance associated with attaching the magnetic current sensor in a position relative to the current rail. As shown, the magnetic current sensor may be positioned such that the w midpoint and dTmidpoint are separated by a particular horizontal distance (e.g., Δx).

As further shown, during operation, the primary Hall cells may sense opposite vertical magnetic field values (e.g., magnetic field BZ1and magnetic field BZ2) when an unknown current passes through the current rail. As further shown, the magnetic current sensor may derive a vertical differential Hall signal based on the magnetic field values sensed by the primary Hall cells, and may determine an amount of current based on the derived vertical differential Hall signal. However, since dTmidpoint and w midpoint are separated by Δx, and since no correction was made to adjust the vertical differential Hall signal derived in order to compensate for Δx, the amount of current determined by the magnetic current sensor may be inaccurate. In order to solve this problem without implementing EOL calibration, an auxiliary lateral Hall cell (e.g., an additional Hall cell associated with measuring a vertical magnetic field) may be included in the magnetic current sensor.

As shown inFIG. 1B, assume that, instead of including only two primary Hall cells separated by a particular distance dT, the magnetic current sensor includes an auxiliary lateral Hall cell (e.g., an auxiliary Hall cell configured to sense a vertical magnetic field) positioned between the two primary Hall cells. As shown, the auxiliary lateral Hall cell may be positioned such that the auxiliary lateral Hall cell lies at dTmidpoint (i.e., the auxiliary lateral Hall cell may lie halfway between the two primary Hall cells). In some implementations, the auxiliary lateral Hall cell may be positioned at another location between the two primary Hall cells (i.e., the auxiliary lateral Hall cell may be positioned at a location between the primary Hall cells other than at dTmidpoint).

As further shown, during operation, the primary Hall cells may sense opposite vertical magnetic field values (e.g., magnetic field BZ1and magnetic field BZ2) when an unknown current passes through the current rail, and the auxiliary lateral Hall cell may sense another vertical magnetic field value (e.g., magnetic field BZC) at dTmidpoint. As further shown, the magnetic current sensor may derive a vertical differential Hall signal based on the vertical magnetic field values sensed by the primary Hall cells, and may derive an auxiliary vertical Hall signal based on the vertical magnetic field value sensed by the auxiliary lateral Hall cell. As further shown, the magnetic current sensor may then determine a corrected vertical differential Hall signal based on the vertical differential Hall signal and the auxiliary vertical Hall signal (e.g., without EOL calibration), and may determine the amount of current, accordingly.

In this way, a magnetic current sensor may include an auxiliary lateral Hall cell positioned between two primary Hall cells. The auxiliary lateral Hall cell may sense a vertical magnetic field value, associated with a magnetic field generated by a current passing through a current rail, at a position between the two primary Hall cells. The vertical magnetic field value, sensed by the auxiliary lateral Hall cell, may then be used to correct a vertical differential Hall signal error that arises due to a horizontal positioning error associated with attaching the magnetic current sensor in a position relative to the current rail.

For the purposes ofFIG. 1C, once again assume that the magnetic current sensor is attached in a position relative to a symmetrical current rail that is external to the magnetic current sensor and that has a width w. Further, assume that the magnetic current sensor includes a pair of primary Hall cells separated from a face of the current rail by a particular vertical distance (e.g., zT).

As shown inFIG. 1C, the magnetic current sensor may be vertically positioned in a position relative to the current rail such that the pair of primary Hall cells is separated from a face of the current rail by zT. However, as shown, zTmay comprise a known vertical distance associated with the geometry of the magnetic current sensor (e.g., z0) and an unknown vertical distance associated with a vertical positioning error (e.g., Δz).

As further shown, during operation, the primary Hall cells may sense opposite vertical magnetic field values (e.g., magnetic field BZ1and magnetic field BZ2) when an unknown current passes through the current rail. As further shown, the magnetic current sensor may derive a vertical differential Hall signal based on the magnetic field values sensed by the primary Hall cells, and may determine an amount of current based on the derived vertical differential Hall signal. However, since zTis not equal to z0(e.g., due to the Δz vertical positioning error), and since no correction was made to adjust the vertical differential Hall signal derived in order to compensate for Δz, the amount of current determined by the magnetic current sensor may be inaccurate. In order to solve this problem without implementing EOL calibration, a set of auxiliary vertical Hall cells (e.g., a set of Hall cells associated with measuring a horizontal magnetic field) may be included in the magnetic current sensor.

As shown inFIG. 1D, assume that, instead of including only two primary Hall cells, the magnetic current sensor includes a set of three auxiliary vertical Hall cells (e.g., a set of auxiliary vertical Hall cells configured to sense a horizontal magnetic field). As shown, the set of auxiliary vertical Hall cells may be positioned such that a first auxiliary vertical Hall cell and a second auxiliary vertical Hall cell are adjacent to the two primary Hall cells (e.g., in a y-direction along the current rail), and such that a third auxiliary vertical Hall cell is positioned between the first auxiliary vertical Hall cell and the second auxiliary vertical Hall cell (e.g., at dTmidpoint). In some implementations, the auxiliary vertical Hall cells may be positioned in another manner (e.g., such that the third auxiliary vertical Hall cell does not lie at dTmidpoint between the first auxiliary vertical Hall cell and the second auxiliary vertical Hall cell). In some implementations, the second auxiliary vertical Hall cell may be optional, as further described below.

As further shown, during operation, the primary Hall cells may sense opposite vertical magnetic field values (e.g., magnetic field BZ1and magnetic field BZ2) when an unknown current passes through the current rail, and the first auxiliary vertical Hall cell, the second auxiliary vertical Hall cell, and the third auxiliary vertical Hall cell may sense a first horizontal magnetic field value (e.g., magnetic field BX1), a second horizontal magnetic field value (e.g., magnetic field BX2), and a third horizontal magnetic field value (e.g., magnetic field BXC), respectively. As further shown, the magnetic current sensor may derive a vertical differential Hall signal based on the vertical magnetic field values sensed by the primary Hall cells, and may derive an auxiliary horizontal Hall signal based on the horizontal magnetic field values sensed by the set of auxiliary vertical Hall cells. As further shown, the magnetic current sensor may then determine a corrected vertical differential Hall signal based on the vertical differential Hall signal and the auxiliary horizontal Hall signal (e.g., without EOL calibration), and may determine the amount of current, accordingly.

In this way, a magnetic current sensor may include a set of auxiliary vertical Hall cells positioned with respect to two primary Hall cells. The set of auxiliary vertical Hall cells may sense a set of horizontal magnetic field values, associated with a magnetic field generated by a current passing through a current rail. The set of horizontal magnetic field values, sensed by the set of auxiliary vertical Hall cells, may then be used to correct a vertical differential Hall signal error that arises due to a vertical positioning error associated with attaching the magnetic current sensor in a position relative to the current rail.

In some implementations, the magnetic current sensor may include the auxiliary lateral Hall cell and the set of auxiliary vertical Hall cells, as described below. In this way, the magnetic current sensor may be capable of compensating for both a horizontal positioning error and a vertical positioning error associated with attaching the magnetic current sensor to the current rail.

FIG. 2is a diagram of an example environment200in which apparatuses described herein may be implemented. As shown inFIG. 2, environment200may include an external current rail210, a galvanic isolation component220, and a magnetic current sensor230.

External current rail210may include an electrically conductive track between two or more electronic components. For example, external current rail210may include a trace on a PCB that connects two components of an electrical circuit. In some implementations, a current may pass through external current rail210(e.g., from one electrical component to another electrical component, from a current source to an electrical component, etc.).

Galvanic isolation component220may include a component that isolates magnetic current sensor230from external current rail210such that current, passing through external current rail210, may not flow into magnetic current sensor230. In some implementations, galvanic isolation220may be placed (e.g., between external current rail210and magnetic current sensor230) such that magnetic current sensor230is capable of sensing a magnetic field generated by the current passing through external current rail210.

Magnetic current sensor230may include a sensor designed to determine an amount of current passing through external current rail210. For example, magnetic current sensor230may determine the amount of current passing through external current rail210based on sensing a magnetic field generated by the current. In some implementations, magnetic current sensor230may be positioned such that magnetic current sensor230is separated from external current rail210by galvanic isolation component220. In some implementations, magnetic current sensor230may include a differential Hall component (e.g., including a pair of primary Hall cells, an auxiliary lateral Hall cell, and/or a set of auxiliary vertical Hall cells) associated with sensing the magnetic field generated by the current, and one or more other components. Additional details regarding magnetic current sensor230are described below with regard toFIG. 3. In some implementations, magnetic current sensor230may be housed in package comprising a semiconductor chip.

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 components of a magnetic current sensor230included in the example environment200ofFIG. 2. As shown, magnetic current sensor230may include a differential Hall component310, an analog-to-digital convertor (ADC)320, a digital signal processor (DSP)330, a memory component340, and a digital interface350.

Differential Hall component310may include a component designed to sense a magnetic field generated by a current passing through external current rail210. In some implementations, differential Hall component may include a pair of primary Hall cells, an auxiliary lateral Hall cell, and a set of auxiliary vertical Hall cells. Each Hall cell may be capable of sensing a magnetic field value (e.g., a vertical magnetic field value or a horizontal magnetic field value). In some implementations, each Hall cell may provide information associated with the sensed magnetic field values to ADC320. Alternatively, differential Hall cell component310may process analog signals, associated with the sensed magnetic fields (e.g., without analog-to-digital conversion by ADC320) in order to determine a corrected differential Hall signal. Additional details regarding differential Hall component310are described below with regard toFIG. 4.

ADC320may include an analog-to-digital converter that converts an analog signal (e.g., a voltage signal) from differential Hall component310to a digital signal. For example, ADC320may convert analog signals, received from differential Hall component310, into digital signals to be processed by DSP330. ADC320may provide the digital signals to DSP330. In some implementations, magnetic current sensor230may 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 a digital signal from ADC320and may process the digital signal to form an output (e.g., information that identifies the amount of current passing through external current rail210, information associated with the differential Hall signal, information associated with the auxiliary Hall signal, etc.). For example, DSP330may derive and/or receive a digital signal corresponding to a vertical magnetic field value sensed by primary Hall cell(s), the auxiliary lateral Hall cell, and/or the set of auxiliary vertical Hall cells. DSP330may determine a corrected differential Hall signal based on the derived and/or received digital signal(s), and may provide information associated with the corrected differential Hall signal. While implementations described herein are described in the context of DSP330performing processing on digital signals corresponding to sensed magnetic field values, in some implementations, another component of magnetic sensor may perform a similar type of processing. For example, differential Hall component310may perform processing on analog signals corresponding to sensed magnetic field values (e.g., before analog-to-digital conversion is performed).

Memory340may 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 magnetic current sensor230. In some implementations, memory component340may store a compensation constant that is to be applied during processing performed by DSP330.

Digital interface350may include an interface via which magnetic current sensor230may receive and/or provide information from and/or to another device, such as information associated with an amount of current determined by magnetic current sensor230. For example, digital interface may provide the output determined by DSP330, that identifies the amount of current passing through external current rail210.

The number and arrangement of components shown inFIG. 3are provided as an example. In practice, magnetic current sensor230may include additional components, fewer components, different components, or differently arranged components than those shown inFIG. 3. Additionally, or alternatively, a set of components (e.g., one or more components) of magnetic current sensor230may perform one or more functions described as being performed by another set of components of magnetic current sensor230.

FIGS. 4A-4Care diagrams of example components of a differential Hall component310included in the example magnetic current sensor230ofFIG. 3. As shown inFIG. 4A, one example differential Hall component310may include a set of two primary Hall cells410(e.g., primary Hall cell410-1and primary Hall cell410-2), and an auxiliary lateral Hall cell420.

Primary Hall cell410may include a transducer designed to provide an output in response to sensing a vertical magnetic field value corresponding to a current travelling through external current rail210. For example, primary Hall cell410may provide a vertical magnetic field value that allows magnetic current sensor230(e.g., DSP330, differential Hall component310) to derive (e.g., based on vertical magnetic field values provided by two primary Hall cells410) a vertical differential Hall signal that corresponds to the current passing through external current rail210.

Auxiliary lateral Hall cell420may include a transducer designed to provide an output in response to sensing a vertical magnetic field value associated with correcting a vertical differential Hall signal in order to compensate for a horizontal positioning error associated with attaching magnetic current sensor230to external current rail210. For example, auxiliary lateral Hall cell420may provide an output that allows magnetic current sensor230(e.g., DSP330, differential Hall component310) to derive an auxiliary vertical Hall signal and/or correct the vertical differential Hall signal based on the derived auxiliary vertical Hall signal.

In some implementations, auxiliary lateral Hall cell420may be positioned between primary Hall cell410-1and primary Hall cell410-2. For example, as shown inFIG. 4A, auxiliary lateral Hall cell420may be positioned such that auxiliary lateral Hall cell420lies at a first distance (e.g., d1) from primary Hall cell410-1and a second distance (e.g., d2) from primary Hall cell410-2(e.g., where d1+d2=dT). In some implementations, d1may equal to d2(i.e., auxiliary lateral Hall cell420may be positioned halfway between primary Hall cell410-1and primary Hall cell410-2). Alternatively, d1may not be equal to d2(i.e., auxiliary lateral Hall cell420may not be positioned halfway between primary Hall cell410-1and primary Hall cell410-2). Additionally, whileFIG. 4Ashows distance dTas a distance that is greater than the width of external current rail210(e.g., w), in some implementations, dTmay be less than or equal to w. Additionally, whileFIG. 4Ashows primary Hall cell410-1, primary Hall cell410-2, and auxiliary lateral Hall cell420as being centered with respect to a y-axis, in some implementations, Hall cell410-1, primary Hall cell410-2, or auxiliary lateral Hall cell420may not be centered with respect to the y-axis.

In some implementations, as described below, primary Hall cell410-1, primary Hall cell410-2, and auxiliary lateral Hall cell420may allow magnetic current sensor230(e.g., DSP330, differential Hall component310) to determine an amount of current, passing through external current rail210, based on a corrected vertical differential Hall signal that has been corrected to compensate for a horizontal positioning error associated with attaching magnetic current sensor230in a position relative to external current rail210.

As shown inFIG. 4B, another example differential Hall component310may include two primary Hall cells410, and a set of auxiliary vertical Hall cells430(e.g., auxiliary vertical Hall cell430-1, auxiliary vertical Hall cell430-2, and auxiliary vertical Hall cell430-3).

Auxiliary vertical Hall cells430may include a transducer designed to provide an output in response to sensing a horizontal magnetic field value associated with correcting a vertical differential Hall signal in order to compensate for a vertical positioning error associated with attaching magnetic current sensor230to external current rail210. For example, auxiliary vertical Hall cells430may provide outputs that allow magnetic current sensor230(e.g., DSP330, differential Hall component310) to derive an auxiliary horizontal Hall signal and/or correct the vertical differential Hall signal based on the derived auxiliary horizontal Hall signal.

In some implementations, auxiliary vertical Hall cell430-1and430-2may be positioned adjacent to primary Hall cell410-1and primary Hall cell410-2, respectively. For example, as shown inFIG. 4B, auxiliary vertical Hall cell430-1may be positioned adjacent to primary Hall cell410-1along a y-axis (e.g., an axis that runs parallel to the current along a face of external current rail). Similarly, as shown, auxiliary vertical Hall cell430-2may be positioned adjacent to primary Hall cell410-2along the y-axis. As further shown, auxiliary vertical Hall cell430-3may be positioned between auxiliary vertical Hall cell430-1and auxiliary vertical Hall cell430-2(e.g., along the x-axis) such that auxiliary vertical Hall cell430-3lies at a third distance (e.g., d3) from auxiliary vertical Hall cell430-1and a fourth distance (e.g., d4) from auxiliary vertical Hall cell430-2(e.g., where d3+d4=dT). In some implementations, d3may equal to d4(i.e., auxiliary vertical Hall cell430-3may be positioned halfway between auxiliary vertical Hall cell430-1and auxiliary vertical Hall cell430-2). Alternatively, d3may not be equal to d4(i.e., auxiliary vertical Hall cell430-3may not be positioned halfway between auxiliary vertical Hall cell430-1and auxiliary vertical Hall cell430-2). In some implementations, differential Hall component310may not include auxiliary vertical Hall cell430-2(e.g., auxiliary vertical Hall cell430-2may be optionally included in differential Hall component310). Alternatively, differential Hall component310may not include auxiliary vertical Hall cell430-1(e.g., auxiliary vertical Hall cell430-1may be optionally when differential Hall component310includes auxiliary vertical Hall cell430-2). Additionally, whileFIG. 4Bshows auxiliary vertical Hall cell430-1, auxiliary vertical Hall cell430-2, and auxiliary vertical Hall cell430-3as being centered with respect to the y-axis, in some implementations, auxiliary vertical Hall cell430-1, auxiliary vertical Hall cell430-2, and auxiliary vertical Hall cell430-3may not be being centered with respect to the y-axis.

In some implementations, as described below, primary Hall cell410-1, primary Hall cell410-2, auxiliary vertical Hall cell430-1, auxiliary vertical Hall cell430-2, and auxiliary vertical Hall cell430-3may allow magnetic current sensor230(e.g., DSP330, differential Hall component310) to determine an amount of current, passing through external current rail210, based on a corrected vertical differential Hall signal that has been corrected to compensate for a vertical positioning error associated with attaching magnetic current sensor230to the in a position relative to external current rail210.

As shown inFIG. 4C, in some implementations, differential Hall component310may include primary Hall cell410-1, primary Hall cell410-2, auxiliary lateral Hall cell420, auxiliary vertical Hall cell430-1, auxiliary vertical Hall cell430-2, and auxiliary vertical Hall cell430-3. Such an implementation may allow magnetic current sensor230(e.g., DSP330, differential Hall component310) to determine an amount of current, passing through external current rail210, based on a corrected vertical differential Hall signal that has been corrected to compensate for both a horizontal positioning error and a vertical positioning error associated with attaching magnetic current sensor230in a position relative to external current rail210.

The number and arrangement of components shown inFIGS. 4A-4Care provided as an example. In practice, differential Hall component310may include additional components, different components, or differently arranged components than those shown inFIGS. 4A-4C.

By positioning a pair of primary Hall cells410in positions relative to opposite sides of external current rail210(e.g., with respect to a center of a symmetric current rail), and due to the differential Hall principle, vertical magnetic field values on opposite sides of a center of external current rail210may be differentiated from an external homogeneous magnetic field (e.g., Earth's magnetic field). For example, consider external current rail210(e.g., a PCB trace) of width w, and a magnetic current sensor230positioned in a position relative to external current rail210such that the vertical distance between each of the pair of primary Hall cells410and external current rail210is z.

An example cross section showing geometry of external current rail210with respect to a vertical magnetic field and a horizontal magnetic field is shown inFIG. 5. Based on the geometry shown inFIG. 5, a vertical magnetic field (e.g., Bz(x,z)) at an x-coordinate and a z-coordinate, with respect to external current rail210, may be derived based on Maxwell's 4th Law:

A horizontal magnetic field (e.g., Bx(x,z)) at the x-coordinate and the z-coordinate may be similarly derived:

A graph illustrating an example of how the vertical magnetic field and the horizontal magnetic field vary with respect to x (e.g., for w=1.7 millimeters (mm) and z0=300 μm) is shown inFIG. 6. In some implementations, it is desirable to attach magnetic current sensor230such that primary Hall cells410are positioned such that primary Hall cells410may derive a maximum differential Hall signal (e.g., in order to accurately determine the amount of current). For example, as shown inFIG. 6, it is desirable to position primary Hall cells410(e.g., included in magnetic current sensor230) at approximately x=−1.0 mm and x=1.0 mm (e.g., a distance between primary Hall cell410-1and primary Hall cell410-2equal to 2.0 mm). With such a placement, primary Hall cells410may accurately sense the vertical magnetic field values such that magnetic current sensor230may derive a corresponding vertical differential Hall signal.

In some implementations, magnetic current sensor230(e.g., DSP330, differential Hall component310) may derive the vertical differential Hall signal based on the magnetic field values sensed by primary Hall cell410-1and primary Hall cell410-2. In a case where magnetic current sensor230is positioned such that there is no horizontal positioning error (e.g., when magnetic current sensor230is centered substantially relative or with respect to a center of external current rail210) and where there is no vertical positioning error (e.g., such that z is a known distance equal to z0), the following differential Hall signal may be derived (e.g., where dTis the distance between primary Hall cell410-1and primary Hall cell410-2):

Udifferential⁢-⁢Hall⁡(0,z0)=SHall·(Bz⁡(ⅆT2,z0)-Bz⁡(-ⅆT2,z0))2=SHall·Bz,diff⁡(0,z0);
where Udifferential-Hall(0,z0) represents a vertical differential Hall signal (e.g., in milliVolts (mV)) at the symmetrical center of external current rail210, SHallrepresents a signal conversion factor (e.g., in mV/microTesla (μT)), and Bz,diff(0,z0) represents a vertical magnetic field (e.g., in μT) at the symmetrical center of external current rail210. However, as described above, a horizontal positioning error and/or a vertical positioning error, associated with attaching magnetic current sensor230in a position relative to external current rail210, may arise. Systems and/or methods that may allow magnetic current sensor230to correct a vertical differential Hall signal in order to compensate for a horizontal positioning error are first described below, followed by systems and/or methods that may allow magnetic current sensor230to correct a vertical differential Hall signal in order to compensate for a vertical positioning.

As described above, in some implementations, a horizontal positioning error may occur when attaching magnetic current sensor230in a position relative to external current rail210. For example, a horizontal positioning error may occur when magnetic current sensor230is attached such that magnetic current sensor230is not centered directly relative to a center of external current rail210(e.g., in an x-direction perpendicular to the current and along the face of external current rail210). For example, a horizontal positioning tolerance may allow magnetic current sensor230to be placed 100 μm off center of external current rail210(e.g., Δx=100 μm), placed 200 μm off center of external current rail210(e.g., Δx=200 μm), or the like, thus introducing a horizontal positioning error. In some cases, the vertical differential Hall signal derived from the vertical magnetic field values may be influenced by the horizontal positioning error associated with the placement of magnetic current sensor230as follows:

Udifferential⁢-⁢Hall⁡(Δ⁢⁢x,z0)=SHall·(Bz⁡(ⅆ2+Δ⁢⁢x)-Bz⁡(-ⅆ2+Δ⁢⁢x))2=SHall·Bz,diff⁡(Δ⁢⁢x,z0);
where Udifferential-Hall(Δx,z0) represents a differential Hall signal (e.g., in mV) at horizontal distance Δx from the symmetrical center of external current rail210and known vertical distance z0, SHallrepresents a signal conversion factor (e.g., in mV/μT), and Bz,diff(Δx,z0) represents a magnetic field at horizontal distance Δx from the symmetrical center of external current rail210and known vertical distance z0from external current rail210(e.g., in μT).

As such, the horizontal positioning error may affect (e.g., weaken) the vertical differential Hall signal derived by magnetic current sensor230.FIG. 7shows an example of a dependency of the vertical differential magnetic field, sensed by primary Hall cells410with respect to the horizontal positioning error, from Δx=−4.0 mm to Δx=4.0 mm. As shown, as the positioning error (e.g., Δx) moves further from zero, the vertical differential magnetic field (e.g., used to derive the differential Hall signal) may decrease.FIG. 8an example of a dependency of the vertical differential magnetic field, sensed by primary Hall cells410, with respect to the horizontal positioning error from Δx=−200 μm to Δx=200 μm. As shown, if the horizontal positioning error is equal to ±100 μm, then the vertical differential magnetic field may decrease by approximately −2.2% (e.g., from 200 microTeslas/Amp (μT/A) to approximately 196 μT/A). Similarly, if the horizontal positioning error is equal to ±200 μm, then the vertical differential magnetic field may decrease by approximately −8.4% (e.g., from 200 μT/A to approximately 183 μT/A). Unless a correction is applied in order to compensate for the horizontal positioning error, the horizontal positioning error will result in a similar decrease in the vertical differential Hall signal derived based on the sensed vertical magnetic field values associated with the vertical differential magnetic field. The signal sensitivity decrease resulting from the horizontal positioning error may be compensated for with the inclusion of auxiliary lateral Hall cell420between primary Hall cells410. In some implementations, auxiliary lateral Hall cell420may sense a vertical magnetic field value at a location between primary Hall cells410, and the vertical magnetic field value may be used to compensate for the horizontal positioning error.

For a symmetric external current rail210, (e.g., a straight PCB trace), the target placement for magnetic current sensor230may be the center of external current rail210.FIG. 9is a graphical representation that shows an example of a compensated vertical differential magnetic field with respect to a horizontal positioning error in relation to a symmetric external current rail210. As shown inFIG. 9, for a positioning error range of ±200 μm, the vertical differential magnetic field (e.g., represented by the line corresponding to “Bz, diff (Dx)”), may be corrected based on the vertical magnetic field value sensed by auxiliary lateral Hall cell420(e.g., represented by the line corresponding to “Bz, mid(Dx)”), in order determine the compensated vertical differential magnetic field (e.g., represented by the line corresponding to “Bz, comp(Dx)”) that may be used to derive a corrected vertical differential Hall signal). As shown inFIG. 9, if auxiliary lateral Hall cell420is placed between primary Hall cells410and if magnetic current sensor230is attached exactly on center (e.g., if Δx=0), then auxiliary lateral Hall cell420may sense a vertical magnetic field equal to zero. As shown inFIG. 9, within a particular limit (e.g., −200 μm<Δx<200 μm), the vertical magnetic field value sensed by auxiliary lateral Hall cell420is a linear function of the horizontal positioning error. As such, the auxiliary vertical Hall signal (e.g., derived from the vertical magnetic field value sensed by auxiliary lateral Hall cell420) also behaves linearly. Therefore, it is possible to extract the horizontal positioning error from the auxiliary vertical Hall signal:

UAux=SHall·Bz,Aux=SHall·β·Δ⁢⁢x·I;UMain=SHall·Bz,diff=SHall·(1-α·Δ⁢⁢x2)·S0·I;UAuxUMain=β·Δ⁢⁢x(1-α·Δ⁢⁢x2)·S0≈β·Δ⁢⁢xS0;
where UAuxrepresents the auxiliary vertical Hall signal, UMainrepresents the vertical differential Hall signal, and where α, β, and S0represent known constants associated with external current rail210.

As such, the following correction may be performed, using the auxiliary vertical Hall signal, in order to correct an error that arises in the vertical differential Hall signal due to the horizontal positioning error:

In some implementations, a current rail constant (e.g., c=α1/2·S0/β) may be stored by magnetic current sensor230(e.g., in memory component340as an EEPROM constant for the particular external current rail210). Therefore, based on the vertical differential Hall signal, derived from the vertical magnetic field values sensed by primary Hall cells410, and the auxiliary vertical Hall signal, derived from the vertical magnetic field value sensed by auxiliary lateral Hall cell420, magnetic current sensor230may evaluate the above formula during operation (e.g., via a hardware modules, a state machine in firmware, etc.) in order to compensate for the horizontal positioning error. As described above, examples of the corrected vertical differential magnetic field for different signal errors that arise due to horizontal positioning error with respect to a symmetric external current rail210are shown inFIG. 9by the line corresponding to “Bz,comp(Dx)”. In this way, an auxiliary vertical Hall signal, derived based on a vertical magnetic field value sensed by auxiliary lateral Hall cell420, may be used to compensate for a vertical differential Hall signal error that arises as a result of a horizontal positioning error associated with a symmetric current rail.

FIG. 10is a graphical representation of an example of an uncompensated horizontal positioning sensitivity error and a compensated horizontal positioning sensitivity error for a symmetric external current rail. The uncompensated horizontal positioning sensitivity error in relation to horizontal positioning error is shown by the line corresponding to “Uncomp_Error”. The compensated horizontal positioning sensitivity error in relation to horizontal positioning error is shown by the line corresponding to “Comp_Error”.

In the case of an asymmetric external current rail210(e.g., a current rail with a non-constant width in a direction perpendicular to the current), the maximum vertical differential magnetic field is shifted relative to the center position of the asymmetric external current rail210. The zero vertical magnetic field point is similarly offset (e.g., whereas the zero vertical magnetic field point is located at x=0 for a symmetric external current rail210), but the linear behavior of the vertical differential magnetic field with respect to the horizontal positioning error (as described above) holds true.

FIG. 11is a graphical representation that shows an example of a compensated vertical differential magnetic field with respect to horizontal positioning error in relation to an asymmetric external current rail210. As shown inFIG. 11, for a horizontal positioning error range of ±200 μm, the vertical differential magnetic field (e.g., represented by the line corresponding to “Bz_diff/2”), may be corrected based on the vertical magnetic field value sensed by auxiliary lateral Hall cell420(e.g., represented by the line corresponding to “Bz_Hall3”), in order determine the compensated vertical differential magnetic field (e.g., represented by the line corresponding to “Bcomp”) that may be used to derive a corrected vertical differential Hall signal). As shown inFIG. 11, if auxiliary lateral Hall cell420is placed between primary Hall cells410and if magnetic current sensor230is attached exactly on center (e.g., if Δx=0), then auxiliary lateral Hall cell420may sense a negative magnetic field value (e.g., since external current rail210is asymmetric). As such, a current rail dependent offset (e.g., Δx0, particular to geometry of external current rail210) should be considered when correcting the vertical differential Hall signal error that arises due to the horizontal positioning error:

In some implementations, a set of current rail constants (e.g., c1=α1/2·S0/β, c2=α1/2·Δx0) may be stored by magnetic current sensor230(e.g., as an EEPROM constant for the particular external current rail210).

Therefore, based on the vertical differential Hall signal, derived from the vertical magnetic field values sensed by primary Hall cells410, the auxiliary vertical Hall signal, derived from the vertical magnetic field value sensed by auxiliary lateral Hall cell420, and the current rail dependent offset, magnetic current sensor230may evaluate the above formula during operation in order to compensate for the horizontal positioning error. As described above, examples of the corrected vertical differential magnetic field for different signal errors that arise due to horizontal positioning error with respect to an asymmetric external current rail210are shown inFIG. 11by the line corresponding to “Bcomp”. In this way, an auxiliary vertical Hall signal, derived based on a vertical magnetic field value sensed by auxiliary lateral Hall cell420, may be used to compensate for a vertical differential Hall signal error that arises as a result of a horizontal positioning error associated with an asymmetric current rail.

FIG. 12is a graphical representation of an example of an uncompensated horizontal positioning sensitivity error and a compensated horizontal positioning sensitivity error for an asymmetric external current rail. The uncompensated horizontal positioning sensitivity error in relation to position tolerance is shown by the line corresponding to “Uncomp_Positioning_Error”. The compensated horizontal positioning sensitivity error in relation to position tolerance is shown by the line corresponding to “Comp_Positioning_Error”.

In some implementations, optimal constants (e.g., c1=α1/2·S0/β, c2=α1/2·Δx0, where c2may not be used for a symmetric external current rail210) may be determined from geometry of external current rail210and positioning of primary Hall cells410and auxiliary lateral Hall cell420. For example, fitting the vertical differential Hall signal function and the auxiliary vertical Hall signal function may result in an asymptotically optimal performance. From a practical perspective, the constants may be modified to reach a more desired behavior over a specific Δx region.

In some implementations, the auxiliary vertical Hall signal may be corrected in order to suppress a background field-effect. Implementations described thus far are described in the context of a negligible homogeneous background field (e.g., a background magnetic field significantly less than the vertical differential Hall field). However, if the homogeneous background field is not negligible, then magnetic current sensor230may correct the auxiliary vertical Hall signal based on the background field as follows:
UAux,Background_Corrected=UAux−(UHall1+UHall2)/2;

where UAux,Background_Correctedrepresents the corrected auxiliary vertical Hall signal, UAux, represents the uncorrected auxiliary vertical Hall signal, UHall1represents a Hall signal corresponding to a vertical magnetic field sensed by primary Hall cell410-1, and UHall2represents a Hall signal corresponding to a vertical magnetic field sensed by primary Hall cell410-2.

The auxiliary vertical Hall signal correction may require a modification in the analog front-end of magnetic current sensor230(e.g., chopping scheme and circuitry). The vertical differential Hall signal is already background field corrected by definition:
UMain=(UHall1−UHall2)/2.
where UMainrepresents the vertical differential Hall signal determined based on the vertical magnetic field values sensed by primary Hall cell410-1and primary Hall cell410-2.

FIG. 13is a graphical representation of an example of a compensated vertical differential magnetic field with respect to a background field correction. As shown inFIG. 13, the vertical magnetic field value sensed by auxiliary lateral Hall cell420(e.g., represented by the line corresponding to “Bz_mid (Dx)”) may be corrected by using background field correction function (e.g., represented by the line corresponding to “Bz,ave (uT/A”) in order to determine a background corrected auxiliary vertical magnetic field value (e.g., represented by the line corresponding to “Bz,mid-comp(uT/A)”). The vertical differential magnetic field (e.g., represented by the line corresponding to “Bz,diff(Dx)”) may then be corrected based on the background corrected auxiliary vertical magnetic field value in order to determine the corrected vertical differential magnetic field (e.g., represented by the line corresponding to “Bz,comp(Dx)”).FIG. 14is a graphical representation of an example of an uncompensated horizontal positioning sensitivity error and a compensated horizontal positioning sensitivity error with respect to a background field correction. The uncompensated horizontal positioning sensitivity error in relation to a non-negligible background field is shown by the line corresponding to “Uncomp_Error”. The compensated horizontal positioning sensitivity error in relation to a non-negligible background field is shown by the line corresponding to “Optimal_Comp_Error”.

In some implementations, after determining the corrected vertical differential Hall signal that compensates for the horizontal positioning error, magnetic current sensor230(e.g., DSP330, differential Hall component310) may determine the amount of current passing through external current rail210based on the corrected vertical differential Hall signal, as described above. Magnetic current sensor230may also provide (e.g., via digital interface350) information associated with the amount of current and/or other information sensed, determined, and/or derived by magnetic current sensor230(e.g., information associated with the corrected vertical differential Hall signal, information associated with the auxiliary vertical Hall signal, etc.).

Additionally, or alternatively, (e.g., after determining the vertical differential Hall signal that compensates for the horizontal positioning error, without determining the vertical differential Hall signal that compensates for the horizontal positioning error) magnetic current sensor230may determine a corrected vertical differential Hall signal that compensates for a vertical positioning error associated with attaching magnetic current sensor230in a position relative to external current rail230.

As described above, in some implementations, a vertical positioning error may occur when attaching magnetic current sensor230in a position relative to external current rail210. For example, a vertical positioning error may occur when magnetic current sensor230is attached such that a distance (e.g., in the z-direction perpendicular to the face of external current rail210) between primary Hall cells410and the face of external current rail210is greater than or less than a known distance (e.g., z0) by an unknown amount (e.g., Δz). For example, a vertical positioning tolerance, combined with non-coplanarity of leads, may allow magnetic current sensor230to be placed such that Δz is equal to a value up to ±65 μm, thus introducing a vertical positioning error. Moreover, additional variations of Δz (e.g., ±5 μm) may occur due to swelling associated with magnetic current sensor230(e.g., after magnetic current sensor230is attached to external current rail210). In some cases, the vertical differential Hall signal derived from the vertical magnetic field values sensed by primary Hall cells410may be influenced by the vertical positioning error as follows:
Udifferential-Hall(0,z0+Δz)=SHall·Bz,diff(0,z0+Δz)
where Udifferential-Hall(0,z0+Δz) represents a differential Hall signal (e.g., in mV) at horizontal distance zero from the symmetrical center of external current rail210and an unknown vertical distance z0+Δz, SHallrepresents a signal conversion factor (e.g., in mV/μT), and Bz,diff(0,z0+Δz) represents a magnetic field at horizontal distance zero from the symmetrical center of external current rail210and the unknown vertical distance z0+Δz from external current rail210(e.g., in μT).

As such, the vertical positioning error may affect the vertical differential Hall signal derived by magnetic current sensor230.FIG. 15shows an example of a dependency of the vertical differential magnetic field, sensed by primary Hall cells410with respect to the vertical positioning error, from Δz=−70.0 μm to Δz=70.0 μm. As shown, as the positioning error (e.g., Δz) moves further from zero, the vertical differential magnetic field (e.g., used to derive the vertical differential Hall signal) may be affected. As shown, if the vertical positioning error is equal to ±65 μm, then the vertical differential magnetic field may be affected (e.g., be increased or be decreased) by approximately ±6.6% (e.g., by increasing from approximately 184 microTeslas/Amp (μT/A) to approximately 196 μT/A or by decreasing from approximately 184 μT/A to approximately 172 μT/A). As shown, the sensitivity error is linear over Δz. Unless a correction is applied in order to compensate for the vertical positioning error, the vertical positioning error will result in a similar decrease in the vertical differential Hall signal derived based on the sensed vertical magnetic field values associated with the vertical differential magnetic field. The signal sensitivity decrease resulting from the vertical positioning error may be compensated for with the inclusion of a set of auxiliary vertical Hall cells430. In some implementations, the set of auxiliary vertical Hall cells430may sense a set of horizontal magnetic field values at locations adjacent to primary Hall cells410, and the set of horizontal magnetic field values may be used to compensate for the vertical positioning error in the vertical differential Hall signal.

A back-bias independent vertical differential Hall field may be determined based on the vertical magnetic field values sensed by primary Hall cells410as follow:

Bz,diff⁡(0,z0+Δ⁢⁢z)=Bz,left⁡(0,z0+Δ⁢⁢z)-Bz,right⁡(0,z0+Δ⁢⁢z)2.
Additionally, it is possible to determine a magnetic field value that represents the inhomogeneity of the horizontal magnetic field (e.g., Bx,inh(0, z0+Δz)) based on the horizontal magnetic field values sensed by the set of auxiliary vertical Hall cells430:

Bx,inh⁡(0,z0+Δ⁢⁢z)=Bx,center⁡(0,z0+Δ⁢⁢z)-Bx,left⁡(0,z0+Δ⁢⁢z)+Bx,right⁡(0,z0+Δ⁢⁢z)2;
where Bx,center(0, z0+Δz) represents the horizontal magnetic field value sensed by auxiliary vertical Hall cell430-3, Bx,left(0, z0+Δz) represents the horizontal magnetic field value sensed by auxiliary vertical Hall cell430-1, and Bx,right(0, z0+Δz) represents the horizontal magnetic field value sensed by auxiliary vertical Hall cell430-2. Bx,inh(0, z0+Δz) is also background field compensated, and dependent on Δz (e.g., more so than Bz,diff(0, z0+Δz)).

As such, it is possible to determine a linear combination of the two independent magnetic fields that is Δz invariant while remaining proportional to the current passing through external current rail210:
Bcombined(0,z0+Δz)=C×Bz,diff(0,z0+Δz)−Bx,inh(0,z0+Δz0);
where Bcombined(0, z0) is a combined magnetic field value that compensate for vertical positioning error Δz, and C is a current rail constant, associated with external current rail210and the Hall-cell arrangement, determined based on w, z0, and dT.

Notably, in some implementations, the set of auxiliary vertical Hall cells430may not include auxiliary vertical Hall cell430-2(e.g., shown as optional inFIGS. 4B and 4C). In such a case, Bx,inh(0, z0+Δz)) may be determined as follows:
Bx,inh(0,z0+Δz)=Bx,center(0,z0+Δz)−Bx,left(0,z0+Δz).
However, by auxiliary vertical Hall cell430-2, symmetry between the horizontal magnetic field values may be achieved, in addition to additional robustness against horizontal positioning error (e.g., Δx).

FIG. 16is a graphical representation that shows an example of a combined magnetic field, determined based on a vertical differential magnetic field and a horizontal magnetic field, that is independent of vertical positioning error. As shown, for a vertical positioning error range of ±70 μm, the vertical differential magnetic field (e.g., represented by the line corresponding to “Bz,diff(μT/A)”), may be combined with the horizontal magnetic field value that represents the inhomogeneity of the horizontal magnetic field (e.g., represented by the line corresponding to “Bx,aux(μT/A)”), in order determine a combined magnetic field value (e.g., represented by the line corresponding to “Bcombined (μT/A)”) that has been corrected to compensate for vertical positioning error, and may be used to derive a corrected vertical differential Hall signal).

In some implementations, a horizontal differential Hall signal (e.g., Ux,inh) that represents the differential magnetic field value that corresponds to the inhomogeneity of the horizontal magnetic field (e.g., Bx,inh) may be derived in an analog front-end of magnetic current sensor230(e.g., similar to the manner in which Uz,diff, corresponding to Bz,diff, is derived, as described above). Magnetic current sensor230may then combine the derived Hall signals (e.g., Ux,inhand Uz,diff).

In some implementations, magnetic current sensor230(e.g., DSP330) may be designed to combine the derived Hall signals after analog-to-digital conversion is performed on the derived Hall signals (e.g., by ADC320).FIG. 17Ais a block diagram showing example circuitry associated with combining the derived Hall signals (e.g., the vertical differential Hall signal and the auxiliary horizontal Hall signal), in order to compensate for a vertical positioning error, after analog-to-digital conversion is performed on the derived Hall signals. As shown, analog-to-digital conversion may be separately performed on each derived Hall signal, and the converted derived Hall signals may be combined in the digital domain (e.g., using a geometry dependent EEPROM constant associated with external current rail210).

Alternatively, magnetic current sensor230may be designed to combine the derived Hall signals before analog-to-digital conversion is performed on the derived Hall signals.FIG. 17Bis a block diagram showing example circuitry associated with combining the derived Hall signals, in order to compensate for a vertical positioning error, before analog-to-digital conversion is performed on the derived Hall signals. As shown, magnetic current sensor230may be designed such that the derived Hall signals are combined in the analog domain. Magnetic current sensor230(e.g., ADC320) may then perform analog-to-digital conversion on the combined Hall signal. For example, the derived signals may be combined in the analog domain by implementing a programmable gain amplifier that is configured based on the geometry dependent EEPROM constant (e.g., EEPROM CONST, shown as variation 2). As another example, the derived signals may be combined in the analog domain by implementing a hard wired constant value (e.g., A=2.0, shown as variation 3) when external current rail210has a particular geometry to reach a Δz-invariant behavior of 2×Uz,diff−Ux,inh.

In some implementations, magnetic current sensor230may correct the vertical differential Hall signal for both horizontal positioning error and vertical positioning error (e.g., by implementing auxiliary lateral Hall cell420, and a set of auxiliary vertical Hall cells430), as described below with regard toFIGS. 18A and 18B.

FIGS. 18A and 18Bare flow charts of an example process1800for determining an amount of current, associated with a current passing through a current rail, using a differential Hall signal that has been corrected in order to compensate for a horizontal positioning error and a vertical positioning error associated with attaching a current sensor to the current rail. In some implementations, one or more process blocks of example process1800may be performed by magnetic current sensor230. In some implementations, one or more process blocks may be performed by a device other than magnetic current sensor230, such as a processor connected to magnetic current sensor230.

As shown inFIG. 18A, process1800may include sensing a first vertical magnetic field value associated with a magnetic field generated by a current passing through a current rail (block1805). For example, magnetic current sensor230(e.g., primary Hall cell410-1) may sense a first vertical magnetic field value associated with a magnetic field generated by a current passing through a current rail, as described above.

As further shown inFIG. 18A, process1800may include sensing a second vertical magnetic field value associated with the magnetic field (block1810). For example, magnetic current sensor230(e.g., primary Hall cell410-2) may sense a second vertical magnetic field value associated with the magnetic field, as described above.

As further shown inFIG. 18A, process1800may include sensing a third vertical magnetic field value associated with the magnetic field (block1815). For example, magnetic current sensor230(e.g., auxiliary lateral Hall cell420) may sense a third vertical magnetic field value associated with the magnetic field, as described above.

As further shown inFIG. 18A, process1800may include sensing a first horizontal magnetic field value associated with the magnetic field (block1820). For example, magnetic current sensor230(e.g., auxiliary vertical Hall cell430-1) may sense a first horizontal magnetic field value associated with the magnetic field, as described above.

As further shown inFIG. 18A, process1800may include sensing a second horizontal magnetic field value associated with the magnetic field (block1825). For example, magnetic current sensor230(e.g., auxiliary vertical Hall cell430-2) may sense a second horizontal magnetic field value associated with the magnetic field, as described above.

As further shown inFIG. 18A, process1800may include sensing a third horizontal magnetic field value associated with the magnetic field (block1830). For example, magnetic current sensor230(e.g., auxiliary vertical Hall cell430-3) may sense a third horizontal magnetic field value associated with the magnetic field, as described above.

As shown inFIG. 18B, process1800may include deriving a vertical differential Hall signal based on the first vertical magnetic field value and the second vertical magnetic field value (block1835). For example, magnetic current sensor230(e.g., DSP330, differential Hall component310, etc.) may derive a vertical differential Hall signal based on the first vertical magnetic field value and the second vertical magnetic field value. In some implementations, magnetic current sensor230may derive the vertical differential Hall signal based on providing the first vertical magnetic field value, the second vertical magnetic field value, and a signal conversion factor as inputs to a function that provides, as an output, the vertical differential Hall signal, as described above.

As further shown inFIG. 18B, process1800may include deriving an auxiliary vertical Hall signal based on the third vertical magnetic field value (block1840). For example, magnetic current sensor230(e.g., DSP330, differential Hall component310, etc.) may derive an auxiliary vertical Hall signal based on the third vertical magnetic field value. In some implementations, magnetic current sensor230may derive the auxiliary vertical Hall signal based on providing the third vertical magnetic field value and a signal conversion factor as inputs to a function that provides, as an output, the auxiliary vertical Hall signal, as described above.

As further shown inFIG. 18B, process1800may include determining a first corrected vertical differential Hall signal based on the vertical differential Hall signal and the auxiliary vertical Hall signal (block1845). For example, magnetic current sensor230(e.g., DSP330, differential Hall component310, etc.) may determine a first corrected vertical differential Hall signal based on the vertical differential Hall signal and the auxiliary vertical Hall signal. In some implementations, magnetic current sensor230may determine the first corrected vertical differential Hall signal based on providing the vertical differential Hall signal, the auxiliary vertical Hall signal, a set of known current rail constants, and/or a current rail dependent offset (e.g., in the case of an asymmetric external current rail210) as inputs to a function that provides, as an output, the first corrected vertical differential Hall signal, as described above.

Additionally, or alternatively, magnetic current sensor230may determine a horizontal positioning error, associated with attaching magnetic current sensor230in a position relative to external current rail210, based on the auxiliary vertical Hall signal and the vertical differential Hall signal, as described above. In some implementations, magnetic current sensor230may provide and/or store information associated with the horizontal positioning error.

As further shown inFIG. 18B, process1800may include deriving an auxiliary horizontal Hall signal based on the first horizontal magnetic field value, the second horizontal magnetic field value, and the third horizontal magnetic field value (block1850). For example, magnetic current sensor230(e.g., DSP330, differential Hall component310, etc.) may derive an auxiliary horizontal Hall signal based on the first horizontal magnetic field value, the second horizontal magnetic field value, and the third horizontal magnetic field value. In some implementations, magnetic current sensor230may derive the auxiliary horizontal Hall signal based on providing the first horizontal magnetic field value, the second horizontal magnetic field value, the third horizontal magnetic field value, and a signal conversion factor as inputs to a function that provides, as an output, the auxiliary horizontal Hall signal, as described above.

As further shown inFIG. 18B, process1800may include determining a second corrected vertical differential Hall signal based on the first corrected vertical differential Hall signal and the auxiliary horizontal Hall signal (block1855). For example, magnetic current sensor230(e.g., DSP330, differential Hall component310, etc.) may determine a second corrected vertical differential Hall signal based on the first corrected vertical differential Hall signal and the auxiliary horizontal Hall signal. In some implementations, magnetic current sensor230may determine the second corrected vertical differential Hall signal based on providing the first corrected vertical differential Hall signal, the auxiliary horizontal Hall signal, and/or other information as inputs to a function that provides, as an output, the second corrected vertical differential Hall signal, as described above.

Additionally, or alternatively, magnetic current sensor230may determine a vertical positioning error, associated with attaching magnetic current sensor230in a position relative to external current rail210, based on the auxiliary horizontal Hall signal and the first corrected vertical differential Hall signal, as described above. In some implementations, magnetic current sensor230may provide and/or store information associated with the vertical positioning error.

As further shown inFIG. 18B, process1800may include determining an amount of current, associated with the current passing through the current rail, based on the second corrected vertical differential Hall signal (block1860). For example, magnetic current sensor230(e.g., DSP330, differential Hall component310, etc.) may determine an amount of current, associated with the current passing through external current rail210, based on the second corrected vertical differential Hall signal. In some implementations, magnetic current sensor230may determine the amount of current based on providing the second corrected vertical differential Hall signal as an input to a function that provides, as an output, the amount of current passing through external current rail210. In some implementations, current sensor230may provide and/or store information that identifies the amount of current.

AlthoughFIGS. 18A and 18Bshow example blocks of process1800, in some implementations, process1800may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted inFIGS. 18A and 18B. Additionally, or alternatively, two or more of the blocks of process1800may be performed in parallel.

Implementations described herein may provide a magnetic current sensor that includes one or more auxiliary Hall cells, positioned with respect to two primary Hall cells, that may sense magnetic field values, associated with a magnetic field generated by a current passing through a current rail. Information associated with the magnetic field values sensed by the one or more auxiliary Hall cells may then be used to correct a differential Hall signal error that arises due to a horizontal positioning error and/or a vertical positioning error associated with attaching the magnetic current sensor in a position relative to the current rail.