Patent Grant
9285438
Not Applicable.
Not Applicable.
This invention relates generally to electronic circuits, and, more particularly, to an electronic circuit used with a plurality of magnetic field sensing elements that can rapidly identify an angle of a direction of a magnetic field sensed by the plurality of magnetic field sensing elements.
Planar Hall elements and vertical Hall elements are known types of magnetic field sensing elements that can be used in magnetic field sensors. A planar Hall element tends to be responsive to magnetic field perpendicular to a surface of a substrate on which the planar Hall element is formed. A vertical Hall element tends to be responsive to magnetic field parallel to a surface of a substrate on which the vertical Hall element is formed.
Other types of magnetic field sensing elements are known. For example, a so-called “circular vertical Hall” (CVH) sensing element, which includes a plurality of vertical magnetic field sensing elements, is known and described in PCT Patent Application No. PCT/EP2008/056517, entitled “Magnetic Field Sensor for Measuring Direction of a Magnetic Field in a Plane,” filed May 28, 2008, and published in the English language as PCT Publication No. WO 2008/145662, which application and publication thereof are incorporated by reference herein in their entirety. The CVH sensing element is a circular arrangement of vertical Hall elements arranged over a common circular implant region in a substrate. The CVH sensing element can be used to sense a direction (and optionally a strength) of a magnetic field in a plane of the substrate.
Conventionally, all of the output signals from the plurality of vertical Hall elements within the CVH sensing element are needed in order to determine a direction of a magnetic field. Also conventionally, output signals from the vertical Hall elements of a CVH sensing element are generated sequentially, resulting in a substantial amount of time necessary to generate all of the output signals from the CVH sensing element. Thus, determination of the direction of the magnetic field can take a substantial amount of time.
Various parameters characterize the performance of magnetic field sensing elements. These parameters include sensitivity, which is a change in an output signal of a magnetic field sensing element in response to a change of magnetic field experienced by the magnetic sensing element, and linearity, which is a degree to which the output signal of the magnetic field sensing element varies in direct proportion to the magnetic field. These parameters also include an offset, which is characterized by an output signal from the magnetic field sensing element not representative of a zero magnetic field when the magnetic field sensing element experiences a zero magnetic field.
Another parameter that can characterize the performance of a CVH sensing element is the speed with which output signals from vertical Hall elements within the CVH sensing element can be sampled, and thus, the speed with which a direction of a magnetic field can be identified. Yet another parameter that can characterize the performance of a CVH sensing element is the resolution (e.g., angular step size) of the direction of the magnetic field that can be reported by the CVH sensing element.
As described above, the CVH sensing element is operable, with associated circuits, to provide an output signal representative of an angle of a direction of a magnetic field. Therefore, as described below, if a magnet is disposed upon or otherwise coupled to a so-called “target object,” for example, a camshaft in an engine, the CVH sensing element can be used to provide an output signal representative of an angle of rotation, and/or a rotation speed, of the target object.
For reasons described above, a magnetic field sensor that uses a CVH sensing element may have a limit as to how rapidly the magnetic field sensor can identify the direction of a magnetic field, i.e., a rotation angle or rotation speed of a target object. Furthermore, the magnetic field sensor may provide an angular resolution that is too low (too large an angle step size).
Thus, it would be desirable to provide a magnetic field sensor that uses a CVH sensing element (or, more generally, a plurality of magnetic field sensing elements) that can more rapidly identify a direction of a magnetic field, and that can faster sense the direction of the magnetic field with a higher resolution, particularly when the direction of the magnetic field is rotating.
The present invention provides a magnetic field sensor that uses a CVH sensing element (or, more generally, a plurality of magnetic field sensing elements) that can more rapidly identify a direction of a magnetic field, and that can faster sense the direction of the magnetic field with a higher resolution, particularly when the direction of the magnetic field is rotating.
In accordance with one aspect of the present invention, a method of determining a direction of a directional magnetic field includes generating a table of values. Each value is related to a respective difference between an identified respective value along a sinusoid and a ninety-degree value along the sinusoid taken ninety degrees apart from the identified respective value. One of the identified respective values is at a peak of the sinusoid and other identified respective values are at selected phase increments along the sinusoid. The method also includes receiving the directional magnetic field with a plurality of magnetic field sensing elements generating a corresponding plurality of magnetic field sensing element signals. The method also includes identifying a peak magnetic field sensing element from among the plurality of magnetic field sensing elements that generates a largest one of the plurality of magnetic field sensing element signals as a peak magnetic field sensing element signal. The method also includes identifying a ninety degree magnetic field sensing element from among the plurality of magnetic field sensing elements that has a primary response axis about ninety degrees rotated from a direction of a primary response axis of the peak magnetic field sensing element, the ninety degree magnetic field sensing element generating a ninety degree magnetic field sensing element signal. The method also includes computing a difference between the peak magnetic field sensing element signal and the ninety degree magnetic field sensing element signal. The method also includes comparing the computed difference with the table of values to identify the direction of the directional magnetic field. At least one of the above steps is performed by a processor.
In accordance with another aspect of the present invention, a method of determining a direction of a directional magnetic field includes tracking the direction of the directional magnetic field, wherein the directional magnetic field has a first direction subject to a rotation to a second different direction. The tracking includes receiving the directional magnetic field with a plurality of magnetic field sensing elements generating a corresponding plurality of magnetic field sensing element signals. The tracking further includes converting a peak magnetic field sensing element signal from a peak magnetic field sensing element among the plurality of magnetic field sensing elements with a first analog-to-digital converter to generate a first converted signal, wherein the peak magnetic field sensing element signal is a largest magnetic field sensing element signal from among the plurality of magnetic field sensing element signals. The tracking also includes identifying a next peak magnetic sensing element among the plurality of magnetic field sensing elements that is expected to generate a new largest magnetic field sensing element signal as a next peak magnetic field sensing element signal when the magnetic field rotates to the second different direction. The tracking also includes converting the next peak magnetic field sensing element signal with a second different analog-to-digital converter to generate a second converted signal. The tracking also includes calculating whether the direction of the magnetic field is closer to the first direction or to the second direction. At least one of the above steps is performed by a processor.
In accordance with another aspect of the present invention, an electronic circuit for determining a largest direction of a directional magnetic field includes an initialization processor coupled to receive a plurality of magnetic field sensing element signals generated by a corresponding plurality of magnetic field sensing elements. The initialization processor is configured to generate a table of values. Each value is related to a respective difference between an identified respective value along a sinusoid and a ninety-degree value along the sinusoid taken ninety degrees apart from the identified respective value, wherein one of the identified respective values is at a peak of the sinusoid and other identified respective values are at selected phase increments along the sinusoid. The electronic circuit further includes a find peak processor coupled to the initialization processor. The find peak processor is configured to identify a peak magnetic field sensing element from among the plurality of magnetic field sensing elements that generates a largest one of the plurality of magnetic field sensing element signals as a peak magnetic field sensing element signal. The electronic circuit further includes a track peak processor coupled to receive the table of values and coupled to receive the peak magnetic field sensing element signal. The track peak processor is configured to identify a ninety degree magnetic field sensing element from among the plurality of magnetic field sensing elements that has a primary response axis about ninety degrees rotated from the from a direction of a primary response axis of the peak magnetic field sensing element, the ninety degree magnetic field sensing element generating a ninety degree magnetic field sensing element signal. The track peak processor is also configured to compute a difference between the peak magnetic field sensing element signal and the ninety degree magnetic field sensing element signal. The track peak processor is also configured to compare the computed difference with the table of values to identify the direction of the magnetic field.
In accordance with another aspect of the present invention, an electronic circuit for determining a direction of a directional magnetic field that has a first direction subject to a rotation to a second different direction, includes a plurality of magnetic field sensing elements configured to generate a corresponding plurality of magnetic field sensing element signals responsive to the directional magnetic field. The electronic circuit also includes a first analog-to digital converter configured to convert a largest magnetic field sensing element signal as a peak magnetic field sensing element signal from a peak magnetic field sensing element to generate a first converted signal. The electronic circuit also includes a track peak processor configured to identify a second different magnetic sensing element among the plurality of magnetic field sensing elements and proximate to the identified peak magnetic field sensing element as a next peak magnetic field sensing element signal that is expected to generate a new largest magnetic field sensing element signal as a next peak magnetic field sensing element signal when the directional magnetic field rotates to the second different direction. The electronic circuit also includes a second analog-to-digital configured to convert the next peak magnetic field sensing element signal to generate a second converted signal. The track peak processor is coupled to receive the first and second converted signals and is further configured to calculate whether the direction of the magnetic field is closer to the first direction or to the second direction.
In accordance with another aspect of the present invention, a method of processing signals generated by a plurality of magnetic field sensing elements includes exposing the plurality of magnetic field sensing elements to a rotating magnetic field and recording maxima and minima signal values for each one of the plurality of magnetic field sensing elements. The method also includes selecting a first one of the plurality of magnetic field sensing elements as a basis magnetic field sensing element having a basis maximum signal value and a basis minimum signal value. The method also includes computing a plurality of initial offset correction values associated with the plurality of magnetic field sensing elements by computing a difference between the basis maximum signal value and the maximum value for each one of the maxima signal values. The method also includes correcting the signals generated by the plurality of magnetic field sensing elements by using the initial offset correction values. At least one of the above steps is performed by a processor.
In accordance with another aspect of the present invention, an electronic circuit for processing signals generated by a plurality of magnetic field sensing element includes an initialization processor coupled to receive the signals generated by a plurality of magnetic field sensing elements while the plurality of magnetic field sensing elements are exposed to a rotating magnetic field. The initialization processor is configured to select a first one of the plurality of magnetic field sensing elements as a basis magnetic field sensing element having a basis maximum signal value and a basis minimum signal value. The initialization processor is further configured to compute a plurality of initial offset correction values associated with the plurality of magnetic field sensing elements by computing a difference between the basis maximum signal value and the maximum value for each one of the maxima signal values. The initialization processor is further configured to correct the signals generated by the plurality of magnetic field sensing elements by using the initial offset correction values.
The foregoing features of the invention, as well as the invention itself may be more fully understood from the following detailed description of the drawings, in which:
Before describing the present invention, some introductory concepts and terminology are explained. As used herein, the term “sensing element” is used to describe a variety of types of electronic elements that can sense a characteristic of the environment. For example, sensing elements include, but are not limited to, pressure sensing elements, temperature sensing elements, motion sensing elements, light sensing elements, acoustic sensing elements, and magnetic field sensing elements.
As used herein, the term “sensor” is used to describe a circuit or assembly that includes a sensing element and other components. In particular, as used herein, the term “magnetic field sensor” is used to describe a circuit or assembly that includes a magnetic field sensing element and electronics coupled to the magnetic field sensing element.
As used herein, the term “magnetic field sensing element” is used to describe a variety of electronic elements that can sense a magnetic field. The magnetic field sensing elements can be, but are not limited to, Hall effect elements, magnetoresistance elements, or magnetotransistors. As is known, there are different types of Hall effect elements, for example, a planar Hall element, a vertical Hall element, and a circular Hall element. As is also known, there are different types of magnetoresistance elements, for example, a giant magnetoresistance (GMR) element, an anisotropic magnetoresistance element (AMR), a tunneling magnetoresistance (TMR) element, an Indium antimonide (InSb) sensor, and a magnetic tunnel junction (MTJ).
As is known, some of the above-described magnetic field sensing elements tend to have an axis of maximum sensitivity parallel to a substrate that supports the magnetic field sensing element, and others of the above-described magnetic field sensing elements tend to have an axis of maximum sensitivity perpendicular to a substrate that supports the magnetic field sensing element. In particular, planar Hall elements tend to have axes of sensitivity perpendicular to a substrate, while magnetoresistance elements and vertical Hall elements (including circular vertical Hall (CVH) sensing elements) tend to have axes of sensitivity parallel to a substrate.
Magnetic field sensors are used in a variety of applications, including, but not limited to, an angle sensor that senses an angle of a direction of a magnetic field, a current sensor that senses a magnetic field generated by a current carried by a current-carrying conductor, a magnetic switch that senses the proximity of a ferromagnetic object, a rotation detector that senses passing ferromagnetic articles, for example, magnetic domains of a ring magnet, and a magnetic field sensor that senses a magnetic field density of a magnetic field.
While a circular vertical Hall (CVH) magnetic field sensing element, which has a plurality of vertical Hall magnetic field sensing elements, is described in examples below, it should be appreciated that the same or similar techniques and circuits apply to any type of sensing elements and to any type of sensors, i.e., to any type of measuring devices. In particular similar circuits and techniques apply to a plurality of separate vertical Hall elements, not arranged in a CVH structure.
Referring to
A particular vertical Hall element (e.g., 12a) within the CVH sensing element 12, which, for example, can have five adjacent contacts, can share some, for example, four, of the five contacts with a next vertical Hall element (e.g., 12b). Thus, a next vertical Hall element can be shifted by one contact from a prior vertical Hall element. For such shifts by one contact, it will be understood that the number of vertical Hall elements is equal to the number of vertical Hall element contacts, e.g., 32. However, it will also be understood that a next vertical Hall element can be shifted by more than one contact from the prior vertical Hall element, in which case, there are fewer vertical Hall elements than there are vertical Hall element contacts in the CVH sensing element.
A center of a vertical Hall element 0 is positioned along an x-axis 20 and a center of vertical Hall element 8 is positioned along a y-axis 22. In the exemplary CVH 12, there are thirty-two vertical Hall elements and thirty-two vertical Hall element contacts. However, a CVH can have more than or fewer than thirty-two vertical Hall elements and more than or fewer than thirty-two vertical Hall element contacts.
In some applications, a circular magnet 14 having a south side 14a and a north side 14b can be disposed over the CVH 12. The circular magnet 14 tends to generate a magnetic field 16 having a direction from the north side 14a to the south side 14b, here shown to be pointed to a direction of about forty-five degrees relative to x-axis 20. Other magnets having other shapes and configurations are possible.
In some applications, the circular magnet 14 is mechanically coupled to a rotating object (a target object), for example, an automobile crank shaft or an automobile camshaft, and is subject to rotation relative to the CVH sensing element 12. With this arrangement, the CVH sensing element 12 in combination with an electronic circuit described below can generate a signal related to the angle of rotation of the magnet 14.
Referring now to
Referring now to
The graph 50 includes a signal 52 representative of output signal levels from the plurality of vertical Hall elements of the CVH taken sequentially with the magnetic field of
Referring briefly to
In
A sine wave 54 is provided to more clearly show the ideal behavior of the signal 52. The signal 52 has variations due to vertical Hall element offsets, which tend to somewhat randomly cause element output signals to be too high or too low relative to the sine wave 54, in accordance with offset errors for each element. The offset signal errors are undesirable. In some embodiments, the offset errors can be reduced by “chopping” each vertical Hall element. Chopping will be understood to be a process by which vertical Hall element contacts of each vertical Hall element are driven in different configurations and signals are received from different ones of the vertical Hall element contacts of each vertical Hall element to generate a plurality of output signals from each vertical Hall element. The plurality of signals can be arithmetically processed (e.g., summed or otherwise averaged) resulting in a signal with less offset.
Full operation of the CVH sensing element 12 of
As will be understood from PCT Patent Application No. PCT/EP2008/056517, groups of contacts of each vertical Hall element can be used in a multiplexed or chopped arrangement to generate chopped output signals from each vertical Hall element. Thereafter, or in parallel (i.e., at the same time), a new group of adjacent vertical Hall element contacts can be selected (i.e., a new vertical Hall element), which can be offset by one or more elements from the prior group. The new group can be used in the multiplexed or chopped arrangement to generate another chopped output signal from the next group, and so on.
Each step of the signal 52 can be representative of a chopped output signal from one respective group of vertical Hall element contacts, i.e., from one respective vertical Hall element. However, in other embodiments, no chopping is performed and each step of the signal 52 is representative of an unchopped output signal from one respective group of vertical Hall element contacts, i.e., from one respective vertical Hall element. Thus, the graph 52 is representative of a CVH output signal with or without the above-described grouping and chopping of vertical Hall elements.
It will be understood that, using techniques described above in PCT Patent Application No. PCT/EP2008/056517, a phase of the signal 52 (e.g., a phase of the signal 54) can be found and can be used to identify the pointing direction of the magnetic field 16 of
Referring now to
A magnet (not shown) can be disposed proximate to the CVH sensing element 72, and can be coupled to a target object (not shown). The magnet can be the same as or similar to the magnet 14 of
As described above, the CVH sensing element 72 can have a plurality of vertical Hall elements, each vertical Hall element comprising a group of vertical Hall element contacts (e.g., five vertical Hall element contacts), of which the vertical Hall element contact 73 is but one example.
In some embodiments, a switching circuit 74 can provide sequential CVH differential output signals 72a, 72b from the CVH sensing element 72.
The CVH differential output signal 72a, 72b is comprised of sequential output signals taken one-at-a-time around the CVH sensing element 72, wherein each output signal is generated on a separate signal path and switched by the switching circuit 74 into the path of the differential output signal 72a, 72b. The signal 52 of
In one particular embodiment, the number of vertical Hall elements (each comprising a group of vertical Hall element contacts) in the CVH sensing element 72 is equal to the total number of sensing element positions, N. In other words, the CVH differential output signal 72a, 72b can be comprised of sequential output signals, wherein the CVH differential output signal 72a, 72b is associated with respective ones of the vertical Hall elements in the CVH sensing element 72 as the switching circuit 74 steps around the vertical Hall elements of the CVH sensing element 72 by increments of one, and N equals the number of vertical Hall elements in the CVH sensing element 72. However, in other embodiments, the increments can be by greater than one vertical Hall element, in which case N is less than the number of vertical Hall elements in the CVH sensing element 72.
In one particular embodiment, the CVH sensing element 72 has thirty-two vertical Hall elements, i.e., N=32, and each step is a step of one vertical Hall element contact position (i.e., one vertical Hall element position). However, in other embodiments, there can be more than thirty-two or fewer than thirty-two vertical Hall elements in the CVH sensing element 72, for example sixty-four vertical Hall elements. Also, the increments of vertical Hall element positions, n, can be greater than one vertical Hall element contact.
In some embodiments, another switching circuit 76 can provide the above-described “chopping” of groups of the vertical Hall elements within the CVH sensing element 72. Chopping will be understood to be an arrangement in which a group of vertical Hall element contacts, for example, five vertical Hall element contacts that form one vertical Hall element, are driven with current sources 86 in a plurality of different connection configurations, and signals are received from the group of vertical Hall element contacts in corresponding different configurations to generate the CVH differential output signal 72a, 72b. Thus, in accordance with each vertical Hall element position, n, there can be a plurality of sequential output signals during the chopping, and then the group increments to a new group, for example, by an increment of one vertical Hall element contact.
The sensing portion 71 can also include current sources 86 configured to drive the CVH sensing element 72 when the CVH sensing element 72.
While current sources 86 are shown, in other embodiments, the current sources 86 can be replaced by voltage sources.
The magnetic field sensor 70 includes an oscillator 78 that provides clock signals 78a, 78b, 78c, which can have the same or different frequencies. A divider 80 is coupled to receive the clock signal 78a and configured to generate a divided clock signal 80a. A switch control circuit 82 is coupled to receive the divided clock signal 80a and configured to generate switch control signals 82a, which are received by the switching circuits 74, 76 to control the sequencing around the CVH sensing element 72, and optionally, to control the chopping of groups of vertical Hall elements within the CVH sensing element 72 in ways described above.
The magnetic field sensor 70 can include a divider 88 coupled to receive the clock signal 78c and configured to generate a divided clock signal 88a, also referred to herein as an “angle update clock” signal.
The magnetic field sensor 70 also includes an x-y direction component circuit 90. The x-y direction component circuit 90 can include an amplifier 92 coupled to receive the CVH differential output signals 72a, 72b. The amplifier 92 is configured to generate an amplified signal 92a. A bandpass filter 94 is coupled to receive the amplified signal 92a and configured to generate a filtered signal 94a. A comparator 96, with or without hysteresis, is configured to receive the filtered signal 94a. The comparator 96 is also coupled to receive a threshold signal 120. The comparator 96 is configured to generate a thresholded signal 96a generated by comparison of the filtered signal 94a with the threshold signal 120.
The x-y direction component circuit 90 also includes an amplifier 114 coupled to receive the divided clock signal 88a. The amplifier 114 is configured to generate an amplified signal 114a. A bandpass filter 116 is coupled to receive the amplified signal 114a and configured to generate a filtered signal 116a. A comparator 118, with or without hysteresis, is coupled to receive the filtered signal 116a. The comparator 118 is also coupled to receive a threshold signal 122. The comparator 118 is configured to generate a thresholded signal 118a by comparison of the filtered signal 116a with the threshold signal 122.
The bandpass filters 94, 116 can have center frequencies equal to 1/T, where T is the time that it takes to sample all of the vertical Hall elements within the CVH sensing element 72.
It should be understood that the amplifier 114, the bandpass filter 116, and the comparator 118 provide a delay of the divided clock signal 88a in order to match a delay of the circuit channel comprised of the amplifier 92, the bandpass filter 94, and the comparator 96. The matched delays provide phase matching, in particular, during temperature excursions of the magnetic field sensor 70.
A counter 98 can be coupled to receive the thresholded signal 96a at an enable input, to receive the clock signal 78b at a clock input, and to receive the thresholded signal 118a at a reset input.
The counter 98 is configured to generate a phase signal 98a having a count representative of a phase difference between the thresholded signal 96a and the thresholded signal 118a.
The phase shift signal 98a is received by a latch 100 that is latched upon an edge of the divided clock signal 88a. The latch 100 is configured to generate a latched signal 100a, also referred to herein as an “x-y angle signal.”
It will be apparent that the latched signal 100a is a multi-bit digital signal that has a value representative of a direction of an angle of the magnetic field experience by the CVH sensing element 72, and thus, an angle of the magnet and target object.
In some embodiments, the clock signals 78a, 78b, 78c each have a frequency of about 30 MHz, the divided clock signal 80a has a frequency of about 8 MHz, and the angle update clock signal 88a has a frequency of about 30 kHz. However in other embodiments, the initial frequencies can be higher or lower than these frequencies
With the magnetic field sensor 70, it will be appreciated that an update rate of the x-y angle signal 100a occurs at a rate equivalent to a rate at which all of the vertical Hall elements within the CVH sensing element 72 are collectively sampled.
Referring now to
As with the magnetic field sensor 70 of
A switching circuit 154 can provide a CVH differential output signal 156a, 156b from a selected one of the vertical Hall elements within the CVH sensing element 72. However, the switching circuit 154 can also provide differential signals 156a, 156b between a selected two of the vertical Hall elements within the CVH sensing element 72. The selections can move among the vertical Hall elements.
The switching circuit 154 can also provide another sequential CVH differential output signal 158a, 158b from another selected one of the vertical Hall elements within the CVH sensing element 72. However, the switching circuit 154 can also provide differential signals 158a, 158b between a selected two of the vertical Hall elements within the CVH sensing element 72. The selections can move among the vertical Hall elements.
As will become apparent from discussion below, unlike the differential signal 72a, 72b generated by the CVH sensing element 72 in
Chopping, and as may be provided by the switching circuit 76 of
The sensing portion 151 includes current sources 86. The sensing portion 151 can also include a switching control circuit 152, configured to provide a switching control signal 152a to control the switching circuit 154, and therefore, to control the vertical Hall elements upon which the magnetic field sensor 150 dwells.
The magnetic field sensor 150 also includes an x-y direction component circuit 153. The x-y direction component circuit 153 is coupled to receive the two differential signals 156a, 156b, and 158a, 158b and is configured to generate a switching circuit control signal 164b, which essentially controls the t vertical Hall elements within the CVH sensing element 72 upon which the magnetic field sensor 150 dwells.
The x-y direction component circuit 153 can include a first analog-to-digital converter 160 coupled to receive the CVH differential output signal 156a, 156b and a second analog-to-digital converter 162 coupled to receive the other CVH differential output signal 158a, 158b. The two analog-to-digital converters 160, 162 are configured to generate respective digital signals 160a, 162a.
An x-y angle processor 164 is coupled to receive the two digital signals 160a, 162a and configured to generate an x-y angle signal 164a. The x-y angle processor 164 is also configured to generate the switching circuit control signal 164b. The x-y angle processor 164 is also configured to generate a control signal 164c to control which one of the analog-to-digital converters 160, 162 is converting at any particular time.
It will become apparent from discussion below that the x-y angle processor 164 can control which vertical Hall elements within the CVH sensing element 72 are being processed. For any given direction of magnetic field it will be understood that some, for example, one, of the vertical Hall elements within the CVH sensing element 72 generates a largest positive output signal, and others, for example, one other, of the vertical Hall elements within the CVH sensing element 72 generates a largest negative output signal. It will also be understood that for the given direction of the magnetic field some others, for example, one other of the vertical Hall elements within the CVH sensing element 72 generate an output signal that is near zero. Which ones of the vertical Hall elements in the CVH sensing element 72 achieve the above signal levels depends upon an angle of the magnetic field relative to the CVH sensing element 72. Also, it will become apparent from discussing below that, since the signals 160a, 160b are digital signals having a particular resolution, in the digital domain, there can be more than one vertical Hall element that generates the largest positive signal, more than one that generates the largest negative signal, and more than one that generates the zero signal.
Referring now to
The processors 170 can also include an initialization processor 174 coupled to receive the calibrated signals 172a and configured to generate one or more initialized signals 174a. Functions of the initialization processor 174 are described more fully below in conjunction with
However, let it suffice here to say that the initialization processor 174 is coupled to receive a plurality of magnetic field sensing element signals generated by a corresponding plurality of magnetic field sensing elements, for example, by a plurality of vertical Hall elements within the CVH sensing element 72 of
The processors 170 can also include a find peak processor 176 coupled to receive the initialized signals 174a. Functions of the find peak processor 176 are described more fully below in conjunction with
However, let it suffice here to say that the find peak processor 176 configured to identify a magnetic field sensing element (a “peak” magnetic field sensing element) from among the plurality of magnetic field sensing elements, for example, within the CVH sensing element 72 of
The processors 170 can also include a track peak processor 178 coupled to receive information 176b pertaining to the peak magnetic field sensing element and also coupled to receive the lookup table 174b. Functions of the track the processor 178 are described more fully below in conjunction with
However, let it suffice here to say, that the track peak processor 178 is configured to identify a ninety degree magnetic field sensing element from among the plurality of magnetic field sensing elements that has a primary response axis about ninety degrees rotated from the from a direction of a primary response axis of the peak magnetic field sensing element, the ninety degree magnetic field sensing element generating a ninety degree magnetic field sensing element signal. The track peak processor can also be configured to compute a difference between the peak magnetic field sensing element signal and the ninety degree magnetic field sensing element signal, and to compare the computed difference with the table of values to identify the direction of the magnetic field. The track peak processor is configured to generate an x-y angle signal 178b, which is the same as or similar to the x-y angle signal 164a of
Furthermore, in some embodiments, the track peak processor is configured to identify a second different magnetic sensing element among the plurality of magnetic field sensing elements and proximate to the identified peak magnetic field sensing element as a next peak magnetic field sensing element that is expected to generate a new largest magnetic field sensing element signal when the directional magnetic field rotates to the second different direction. The track peak processor is coupled to receive the first and second converted signals 160a, 162a of
The processors 170 can also include reinitialization processor 180. The reinitialization processor 180 is coupled to receive a signal 178a from the track peak processor 178 and configured to generate a recalibration signal 180a. Functions of the recalibration processor are described more fully below in conjunction with
It should be appreciated that
Alternatively, the processing and decision blocks represent steps performed by functionally equivalent circuits such as a digital signal processor circuit or an application specific integrated circuit (ASIC). The flow diagrams do not depict the syntax of any particular programming language. Rather, the flow diagrams illustrate the functional information one of ordinary skill in the art requires to fabricate circuits or to generate computer software to perform the processing required of the particular apparatus. It should be noted that many routine program elements, such as initialization of loops and variables and the use of temporary variables are not shown. It will be appreciated by those of ordinary skill in the art that unless otherwise indicated herein, the particular sequence of blocks described is illustrative only and can be varied without departing from the spirit of the invention. Thus, unless otherwise stated the blocks described below are unordered meaning that, when possible, the steps can be performed in any convenient or desirable order.
Referring now to
Simply stated, the process begins with a calibration at block 202, where gains of signals generated by a plurality of magnetic field sensing elements are calibrated.
At block 204, an initialization occurs, wherein a particular look up table (
At block 206, one of the magnetic field sensing elements (a “peak” magnetic field sensing element) having a largest magnetic field sensing element signal is identified and processed to find a so-called “peak” amplitude.
At block 208, the magnetic field sensing element having the peak amplitude is tracked. The magnetic field sensing element having the peak amplitude can change to other magnetic field sensing elements as a magnetic field being sensed rotates. The magnetic field sensing element having the peak amplitude is processed to identify a pointing direction of a magnetic field.
It should be understood that, because only one (or two) magnetic field sensing elements need to be processed and tracked, the process 200, and the associated magnetic field sensor 150 of
At block 210, the initialization process of block 234 can be repeated.
Referring now to
At block 226, an external directional magnetic field is applied to the magnetic field sensor, for example, the magnetic field sensor 150 of
At block 228, the magnetic field sensing elements are “swept.” In other words, magnetic field sensing element signals from each one of the plurality of magnetic field sensing elements (vertical Hall elements) within the CVH sensing element 72 are collected or sampled. Also at block 228, a magnetic field sensing element from among the plurality of magnetic field sensing elements is identified that generates a largest positive signal value. It will be understood that the identified magnetic field sensing element is approximately aligned with the applied magnetic field.
At block 230 gains of the analog-to-digital converters 160, 162 of
At block 240, the process 220 exits the calibration mode.
The initialization module 204 of
Referring now to
At block 256, in parallel with a physical rotation of the magnetic field at block 254, maximum values, i.e., maximum positive values, and minimum values, i.e., maximum negative values are recorded for each one of the plurality of magnetic field sensing elements within the CVH sensing element 72 of
At block 258, first, any one of the plurality of magnetic field sensing elements is selected to be a “basis” magnetic field sensing element. Then, “delta values” are computed for each one of the plurality of magnetic field sensing elements. The delta values are computed by taking differences between the maximum value recorded for the basis magnetic field sensing element and the maximum values recorded for all of the other ones of the plurality of magnetic field sensing elements. The delta values will be understood to be “first offset correction values,” and can be used to adjust the DC offset of each one of the plurality of magnetic field sensing elements as measurements are taken with the plurality of magnetic field sensing elements. Also at block 258, the maximum and minimum values recorded at block 256 can be adjusted by the respective ones of the first offset correction values.
At block 260, an “actual peak magnitude” is computed. The actual peak magnitude is computed by first taking a sum of the maximum value achieved by the basis magnetic field sensing element plus an absolute value of a minimum value (first corrected by a corresponding one of the first offset correction values) achieved by a magnetic field sensing element one hundred eighty degrees around the CVH sensing element 72 from the basis magnetic field sensing element, and then dividing by two. The actual peak magnitude corresponds to a zero to peak magnitude.
At block 262, a “second offset correction value” is computed. The second offset correction value is computed by taking a difference between the actual peak magnitude computed at block 260 and the peak magnitude of the basis magnetic field sensing element.
At block 264, it is indicated that from this point forward all values read from each one of the plurality of magnetic field sensing elements within the CVH sensing element 72 of
At block 266, a lookup table is generated. The lookup table has a first value corresponding to a differential value generated by a difference between a magnetic field sensing element signal and a magnetic field sensing element signal that is ninety degrees around the CVH sensing element 72 of
Also at block 266, the values in the lookup table generated in accordance with the ideal sinusoid's can be scaled by the actual peak magnitude generated at block 260. In this way values in the lookup table of block 266 can be compared with actual measurements taken below.
The initialization process of
Referring now to
At block 284, magnetic field sensing element signals from all of the magnetic field sensing elements within the CVH sensing element 72 are swept, i.e., magnetic field sensing element signals from each one of the plurality of magnetic field sensing elements within the CVH sensing element 72 are collected or sampled. All of the sampled magnetic field sensing elements can be corrected by the first and second offset correction values generated in blocks 258 and 262 of
At block 286, an actual differential measurement is taken. The actual differential measurement is a difference between the largest magnetic field sensing element signal value of the magnetic field sensing element identified at block 284 and a magnetic field sensing element signal value generated by a magnetic field sensing element ninety degrees around the CVH sensing element from the identified magnetic field sensing element.
It should be appreciated that differential measurements taken here and below can be taken by coupling inputs of one of the two analog-to-digital converters 160, 162 of
At block 288, the actual differential measurement taken at block 286 is compared with values in the lookup table generated in block 266 of
At block 290, the angular offset is stored and can be used to angularly correct any subsequent angular measurements associated with a CVH sensing element 72.
At block 292 the process 280 exits the initialization mode.
Referring now to
Data points 302 correspond to maximum positive signal values achieved by each one of the vertical Hall elements within the CVH sensing element 72 at block 256 of
Referring now to
An ideal sinusoid 322 is shown at a particular phase representative of a zero degree phase. Ideal sinusoid 322a, 322b are shown in predetermined phase increments in one direction apart from the ideal sinusoid 322. Ideal sinusoids 322c, 322d are shown in predetermined phase increments in the other direction apart from the ideal sinusoid 322.
A point 324 on the ideal sinusoid 322 is indicative of a magnitude of the ideal sinusoid 322 at a zero degree phase of the ideal sinusoid 322. A point 326 on the ideal sinusoid 322 is indicative of a magnitude of the ideal sinusoid 322 at a ninety degree phase of the ideal sinusoid 322. The first differential value described above in conjunction with block 266 of
A point 328 on the phase shifted ideal sinusoid 322d is indicative of a magnitude of the phase shifted ideal sinusoid 322d at a zero degree phase of the ideal sinusoid 322. A point 330 on the phase shifted ideal sinusoid 322d is indicative of a magnitude of the phase shifted ideal sinusoid 322d at a ninety degree phase of the ideal sinusoid 322. Another differential value described above in conjunction with block 266 of
It will be understood that the differential value associated with phase shifted ideal sinusoid 322d is different than the differential value associated with the zero degree ideal sinusoid 322. Furthermore, it will be understood that the differential value can be used to identify a phase of the sinusoid, for example, which one of the sinusoids 322, 322a, 322b, 322c, 322d is associated with a particular differential value.
Differential values stored in the lookup table generated at block 266 of
Referring now to
It will be understood that for the given direction of magnetic field experienced by the CVH sensing element 72 of
Thus, the process 350 attempts to identify with a high degree of granularity at what angle the magnetic field is pointing even though it may be pointing between two of the vertical Hall elements, and even though a small range of magnetic field sensing elements within the CVH sensing element 72 of
At block 354, by way of the control signal 164c of
At block 356, it is identified if there is known rotational position information of a sensed magnetic field already available. If there is no rotational position information already available then the process proceeds to block 358.
At block 358, a measured sample value is measured from a random one of the vertical Hall elements of the CVH sensing element 72 of
It will be appreciated that the measured sample value can be any value, because a randomly selected magnetic field sensing element can be at any alignment in relation to the sensed magnetic field, including a zero degree alignment, a ninety degree alignment, a one hundred eighty degree alignment, or any other alignment. Thus, the measured sample value can be zero, a positive value, or a negative value.
At block 360, it is identified if the measured sample value is close to a zero degree value. In other words, it is identified if the measured sample value is large and close to the actual peak magnitude value (positive) identified at block 260 of
At block 360, if the measured sample value is not close to the actual peak value, the process proceeds to block 362. If the measured sample value is close to the actual peak value, the process proceeds to block 363.
At block 363, another vertical Hall element within the CVH sensing element 72 is selected that is ninety degrees around the CVH sensing element from the vertical Hall element randomly selected at block 358. It will be understood that selection of this vertical Hall element that is ninety degrees around the CVH sensing element can result in the magnetic field sensing element that is generating a signal closer to the actual peak signal. The process then proceeds to block 362.
At block 360, if the measured sample value is close to the actual peak value, the process proceeds to block 362.
At block 362, if the sample value generated by the selected magnetic field sensing element is less than zero, then the process proceeds to block 364. At block 364, another vertical Hall element within the CVH sensing element 72 is selected that is one hundred eighty degrees around the CVH sensing element from the vertical Hall element previously selected. The process then proceeds to block 366.
At block 362, if the sample value generated by the selected magnetic field sensing element is not less than zero, then the process proceeds to block 366.
At this point it should be recognized that the selected magnetic field sensing element within the CVH sensing element 72 should be that magnetic field sensing element that is generating a magnetic field sensing element signal value that is the actual peak value identified in block 260 of
At block 366, from the presently selected magnetic field sensing element, a rotation is made by one magnetic field sensing element, for example, in a clockwise direction, from the presently selected magnetic field sensing element. From that newly selected magnetic field sensing element a magnetic field sensing element signal value (a sample value) is taken and stored.
At block 368, it is determined if the sample value taken at block 366 is greater than or equal to the sample value taken at block 364. If the sample value taken at block 366 is greater than or equal to the sample value taken at block 364, then the process proceeds to block 372.
At block 372 is determined if the sample value taken at block 366 is greater than the sample value taken at block 364. At block 372, if the sample value taken at block 366 is greater than the sample value taken at block 364, then the process proceeds to block 374.
At block 374, a location, i.e., a position, of the magnetic field sensing element from which the sample value is taken at block 366 is recorded as a so-called “left edge. The process then returns to block 366. The identified magnetic field sensing element is at one edge of a small range of magnetic field sensing elements within the CVH sensing element 72 that will generate the same magnitude of sample value. The number of magnetic field sensing elements that will generate the same magnitude sample value is related to the number of digital bits (i.e., granularity) that are used to represent the sample values.
At block 372, if the sample value taken at block 366 is not greater than the sample value taken at block 364, then the process returns to block 366.
By looping around the blocks 366, 368, 372, 374, eventually a position of a last magnetic field sensing element in the clockwise direction that produces a largest sample value is identified as the right edge, and the process proceeds to block 370.
At block 370, the right edge magnetic field sensing element position and sample value are recorded.
Referring now to
At block 392, it is identified if a so-called “left edge” has already been identified. The left edge will be understood to be a position of a last magnetic field sensing element in a counterclockwise direction that produces the largest sample value.
At block 392, if the left edge has not already been identified, the process proceeds to block 398
At block 398, a so-called “last element” is identified to be one of the magnetic field sensing elements identified in the loop of blocks 366, 368, 372, 374, some sequential ones of which should have generated the largest sample value. The last element is identified to be the magnetic field sensing element in a counterclockwise direction from the right edge and that generated the largest sample value. At block 398, a position of a magnetic field sensing element for next processing is identified to be the magnetic field sensing element one element counterclockwise from the last element. At block 398 the sample value from this magnetic field sensing element for next processing is measured and stored. The process then proceeds to block 400.
At block 400, if the simple value measured and stored at block 398 is greater than or equal to the sample value of the magnetic field sensing element immediately clockwise from the magnetic field sensing element from which the sample value was taken at block 398, then the process proceeds to block 404.
At block 404, if the sample value measured and stored at block 398 is greater than the sample value of the magnetic field sensing element immediately clockwise from the magnetic field sensing element from which the sample value was taken at block 398, then the process proceeds to block 406.
At block 404, if the sample value measured and stored at block 398 is not greater than the sample value of the magnetic field sensing element immediately clockwise from the magnetic field sensing element from which the sample value was taken at block 398, then the process proceeds to block 408.
At block 406, a location, i.e., a position, of the magnetic field sensing element from which the sample value is taken at block 366 is recorded as a so-called “right edge.” The process then proceeds to block 408. The identified magnetic field sensing element is at another edge of the small range of magnetic field sensing elements within the CVH sensing element 72 that will generate the same magnitude of sample value.
At block 408, from the presently selected magnetic field sensing element, a rotation is made by one magnetic field sensing element, for example, in a counter clockwise direction, from the presently selected magnetic field sensing element. From that newly selected magnetic field sensing element a magnetic field sensing element signal value (a sample value) is taken and stored. The process then returns to block 400.
By looping around the blocks 400, 404, 406, 408, eventually a position of a last magnetic field sensing element in the counter clockwise direction that produces the largest sample value is identified as the left edge, and the process proceeds to block 402.
At block 402, the left edge magnetic field sensing element position and sample value are recorded.
At this point, the above-described small range of magnetic field sensing elements within the CVH sensing element 72 of
For example, in some embodiments, there are sixty-four vertical Hall elements in the CVH sensing element 72, each one of the sixty-four vertical Hall elements incremented by one vertical Hall element contact from an adjacent vertical Hall element. Continuing the example, in some embodiments the sample values of the magnetic field sensing elements have +/−eight bits, i.e., nine bits. For these embodiments, one or two adjacent magnetic field sensing elements within the CVH sensing element may generate the largest sample value. For another exemplary embodiment for which the sample values of the magnetic field sensing elements have +/−3 bits, i.e., 4 bits, seven or eight adjacent magnetic field sensing elements within the CVH sensing element may generate the largest sample value. The number is also determined in part by a direction of the sensed magnetic field relative to the positions of the magnetic field sensing elements.
It is desirable that the magnetic field sensor 150 of
At block 384, a so-called “peak” pointing direction is calculated to be at an angular position midway between the left edge and the right edge identified above. The peak will be understood to represent an angular direction of the sensed magnetic field sensed by the magnetic field sensor 150 of
Where there are an odd number of magnetic field sensing elements between the right edge and the left edge, one of the magnetic field sensing elements between the left edge and the right edge is aligned with the rotational position of the peak. Where there is an even number of magnetic field sensing elements between the right edge and the left edge, there is not a magnetic field sensing element aligned exactly with the peak.
Where there are an odd number of magnetic field sensing elements between the right edge of the left edge, a center one of the magnetic field sensing elements between the right edge and the left edge is identified to be a so-called “peak” magnetic field sensing element. Where there is an even number of magnetic field sensing elements between the right edge and the left edge, a magnetic field sensing element one element, for example, clockwise, from the peak pointing direction identified at block 384 is identified to be the peak magnetic field sensing element.
Also at block 384, a so-called “next peak element” is identified to be the magnetic field sensing element one element, for example, clockwise, from the peak magnetic field sensing element.
Also at block 384, by way of the control signal 164c of
The above processes 350, 390 of
Referring now to
At block 423, one of the analog-to-digital converters 160, 162 of
At block 424, the analog-to-digital converter designated as the peak analog-to-digital converter is used to take a first differential measurement. The first differential measurement is taken between the magnetic field sensing element identified as the peak magnetic field sensing element at block 384 of
At block 426, the analog-to-digital converter designated as the next peak analog-to-digital converter is used to take a second differential measurement. The second differential measurement is taken between the magnetic field sensing element identified at the next peak magnetic field sensing element at block 384 of
It will be appreciated that the conversions performed in blocks 424, 426 can be performed in parallel. However, in other embodiments, the conversions can be performed in series.
At this point two differential measurements have taken, one for each of two adjacent magnetic field sensing elements within the CVH sensing element 72 of
It will be understood from discussion below the designations of peak ADC and next peak ADC can switch back and forth between the two analog-to-digital converters 160, 162 of
The process proceeds to block 428. At block 428, the differential measurement taken at block 424 is compared with the lookup table generated at block 266 of
It will be appreciated that the differential measurements are more sensitive to the phase of the sinusoids of
Returning to
The process proceeds to block 430. At block 430, it is determined if the magnetic field sensing element used to take the differential measurement is aligned with the sensed magnetic field. This determination can be made merely by using the differential measurement. If the differential measurement corresponds for example, to the sinusoids 322 of
At block 430, if the magnetic field sensing element used to take the differential measurement is aligned with the sensed magnetic field, then, optionally, the process can continue to block 442, entering a “reinitialize” mode. The reinitialize mode corresponds to the reinitialize module 230 of
At block 444 the process returns from the reinitialize mode and returns to block 428.
At block 430, if the magnetic field sensing element used to take the differential measurement is not aligned with the sensed magnetic field, the process proceeds to block 432.
At block 432, it is determined if the angle of the sensed magnetic field has rotated into or toward the next peak magnetic field sensing element identified at block 384 of
At block 432, if the angle of the sensed magnetic field has rotated into the next peak magnetic field sensing element and the process proceeds to block 434.
At block 434, designations of the two analog-to-digital converters, originally designated at block 424, 426, are reversed.
At block 436, magnetic field sensing elements are re-designated. The magnetic field sensing element previously designated to be the next peak magnetic field sensing element is now designated to be the peak sensing element. Also, a new next peak sensing element is identified to be adjacent to the newly designated peak sensing element in the direction of rotation of the sensed magnetic field. The process then returns to blocks 424, 426. Conversions can again be done in parallel.
At block 432, if the angle of the sensed magnetic field has not rotated into the next peak magnetic field sensing element and the process proceeds to block 438. Block 438 essentially identifies whether the direction of rotation of the magnetic field has changed to the other rotation.
At block 438, it can be identified by way of the differential measurements being used in comparison with the lookup table 266 of
At block 440, the magnetic field sensing element presently designated as the next peak magnetic field sensing element is changed. A new magnetic field sensing element is designated as the next peak magnetic field sensing element. The new magnetic field sensing element designated as the next peak magnetic field sensing element is selected to be the magnetic field sensing element that is on the opposite side rotationally from the peak magnetic field sensing element from the magnetic field sensing element presently designated as the next peak magnetic field sensing element. The process then returns to block 424.
It will be appreciated this process 420 can track the pointing direction of the sensed magnetic field. It will also be appreciated that, by using two analog-to-digital converters, at the time that the sensed magnetic field rotates from being aligned with one magnetic field sensing element to being aligned with another magnetic field sensing element, samples are already available from the other magnetic field sensing element. Thus, the process 42, used to track the direction of the sensed magnetic field, can be faster and can track faster rotating magnetic fields then a process that uses only one analog-to-digital converter.
Referring now to
At block 454, since, according to block 430 of
At block 456, the differential measurement taken at block 454 is divided by two, and the result is designated to be a new or updated “actual peak magnitude.”
Using the new or updated actual peak magnitude, the lookup table originally generated at block 266 of
At block 460, the process returns to the track peak mode, and, in particular, to block 444 of
Having described preferred embodiments of the invention it will now become apparent to those of ordinary skill in the art that other embodiments incorporating these concepts may be used. Additionally, the software included as part of the invention may be embodied in a computer program product that includes a computer-readable storage medium. For example, such a computer-readable storage medium can include a computer-readable memory device, such as a solid state memory, a hard drive device, a CD-ROM, a DVD-ROM, or a computer diskette, having computer-readable program code segments stored thereon. A computer-readable transmission medium can include a communications link, either optical, wired, or wireless, having program code segments carried thereon as digital or analog signals. Accordingly, it is submitted that that the invention should not be limited to the described embodiments but rather should be limited only by the spirit and scope of the appended claims.
All publications and references cited herein are expressly incorporated herein by reference in their entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4668914 | Kersten et al. | May 1987 | A |
| 4761569 | Higgs | Aug 1988 | A |
| 4829352 | Popovic et al. | May 1989 | A |
| 5541506 | Kawakita et al. | Jul 1996 | A |
| 5572058 | Biard | Nov 1996 | A |
| 5612618 | Arakawa | Mar 1997 | A |
| 5619137 | Vig et al. | Apr 1997 | A |
| 5621319 | Bilotti et al. | Apr 1997 | A |
| 5657189 | Sandhu | Aug 1997 | A |
| 5694038 | Moody et al. | Dec 1997 | A |
| 5831513 | Lue | Nov 1998 | A |
| 5844411 | Vogt | Dec 1998 | A |
| 5942895 | Popovic et al. | Aug 1999 | A |
| 6064199 | Walter et al. | May 2000 | A |
| 6064202 | Steiner et al. | May 2000 | A |
| 6073043 | Schneider | Jun 2000 | A |
| 6091239 | Vig et al. | Jul 2000 | A |
| 6100680 | Vig et al. | Aug 2000 | A |
| 6166535 | Irle et al. | Dec 2000 | A |
| 6232768 | Moody et al. | May 2001 | B1 |
| 6236199 | Irle et al. | May 2001 | B1 |
| 6265864 | De Winter et al. | Jul 2001 | B1 |
| 6288533 | Haeberli et al. | Sep 2001 | B1 |
| 6297627 | Towne et al. | Oct 2001 | B1 |
| 6356741 | Bilotti et al. | Mar 2002 | B1 |
| 6424147 | Kato | Jul 2002 | B1 |
| 6525531 | Forrest et al. | Feb 2003 | B2 |
| 6542068 | Drapp et al. | Apr 2003 | B1 |
| 6545462 | Schott et al. | Apr 2003 | B2 |
| 6622012 | Bilotti et al. | Sep 2003 | B2 |
| 6768301 | Hohe et al. | Jul 2004 | B1 |
| 6969988 | Kakuta et al. | Nov 2005 | B2 |
| 7030606 | Kato et al. | Apr 2006 | B2 |
| 7038448 | Schott et al. | May 2006 | B2 |
| 7085119 | Bilotti et al. | Aug 2006 | B2 |
| 7119538 | Blossfeld | Oct 2006 | B2 |
| 7159556 | Yoshihara | Jan 2007 | B2 |
| 7184876 | Teulings et al. | Feb 2007 | B2 |
| 7235968 | Popovic et al. | Jun 2007 | B2 |
| 7259556 | Popovic et al. | Aug 2007 | B2 |
| 7307824 | Bilotti et al. | Dec 2007 | B2 |
| 7362094 | Voisine et al. | Apr 2008 | B2 |
| 7714570 | Thomas et al. | May 2010 | B2 |
| 7746065 | Pastre et al. | Jun 2010 | B2 |
| 7759929 | Forsyth | Jul 2010 | B2 |
| 7797604 | Lee et al. | Sep 2010 | B2 |
| 7872322 | Schott et al. | Jan 2011 | B2 |
| 7911203 | Thomas et al. | Mar 2011 | B2 |
| 7965076 | Schott | Jun 2011 | B2 |
| 7994774 | Thomas et al. | Aug 2011 | B2 |
| 8321173 | Wallance | Nov 2012 | B2 |
| 20020114269 | Onggosanusi et al. | Aug 2002 | A1 |
| 20050225318 | Bailey | Oct 2005 | A1 |
| 20060011999 | Schott et al. | Jan 2006 | A1 |
| 20070029998 | Popovic et al. | Feb 2007 | A1 |
| 20070105244 | Okita | May 2007 | A1 |
| 20080100285 | Matsumoto et al. | May 2008 | A1 |
| 20090001965 | Ausserlechner et al. | Jan 2009 | A1 |
| 20090121707 | Schott | May 2009 | A1 |
| 20090174395 | Thomas et al. | Jul 2009 | A1 |
| 20100026282 | Kaita et al. | Feb 2010 | A1 |
| 20100102809 | May | Apr 2010 | A1 |
| 20100133632 | Schott | Jun 2010 | A1 |
| 20100156397 | Yabusaki et al. | Jun 2010 | A1 |
| 20100164491 | Kejik et al. | Jul 2010 | A1 |
| 20100181993 | Fernandez et al. | Jul 2010 | A1 |
| 20110031965 | Saruki et al. | Feb 2011 | A1 |
| 20110037459 | Okada | Feb 2011 | A1 |
| 20110248708 | Thomas et al. | Oct 2011 | A1 |
| 20110298447 | Foletto et al. | Dec 2011 | A1 |
| 20120299588 | Petrie | Nov 2012 | A1 |
| Number | Date | Country |
|---|---|---|
| 101995558 | Mar 2011 | CN |
| 102171588 | Aug 2011 | CN |
| 102193073 | Sep 2011 | CN |
| 10 2005 014 509 | Oct 2006 | DE |
| 10 2006 037 226 | Feb 2008 | DE |
| 10 2007 036 984 | Jan 2009 | DE |
| 10 2010 010 560 | Sep 2011 | DE |
| 0 631 416 | Dec 1994 | EP |
| 0 875 733 | Nov 1998 | EP |
| 0 916 074 | May 1999 | EP |
| 2 000 814 | Dec 2008 | EP |
| 58-055688 | Apr 1983 | JP |
| 2003-042709 | Feb 2003 | JP |
| 2005-241269 | Sep 2005 | JP |
| 2010-014607 | Jan 2010 | JP |
| 2010-078366 | Apr 2010 | JP |
| 200643376 | Dec 2006 | TW |
| WO 9810302 | Mar 1998 | WO |
| WO 9854547 | Dec 1998 | WO |
| WO 0002266 | Jan 2000 | WO |
| WO 03036732 | May 2003 | WO |
| WO 2004025742 | Mar 2004 | WO |
| WO 2005029106 | Mar 2005 | WO |
| WO 2006056289 | Jun 2006 | WO |
| WO 2006074989 | Jul 2006 | WO |
| WO 2008 145662 | Dec 2008 | WO |
| WO 2008145662 | Dec 2008 | WO |
| WO 2009124969 | Oct 2009 | WO |
| WO 2013017211 | Feb 2013 | WO |
| Entry |
|---|
| Drljaca, et al.; “Nonlinear Effects in Magnetic Angular Position Sensor With Integrated Flux Concentrator;” Proc. 23rd International Conference on Microelectronics (MIEL 2002); vol. 1; NIS; Yugoslavia; May 12-15, 2002; pp. 223-226. |
| Taiwan Office Action dated Fabruwy 18, 2014; for TW Pat. App. No. 101132371; 7 pages. |
| Taiwan Office Action (English translation) dated Feb. 18, 2014; for TW Pat. App. No. 101132371; 8 pages. |
| Notice of Allowance dated Mar. 14, 2014; for U.S. Appl. No. 13/035,257; 7 pages. |
| Letter to Taiwan International Patent & Law Office dated Apr. 28, 2014; for Taiwan Pat. App. No. 101132371; 3 pages. |
| Email from Taiwan International Patent & Law Office dated May 16, 2014; for Taiwan Pat. App. No. 101132371; 2 pages. |
| Taiwan Response to Office Action (with claims in Taiwanese) filed May 16, 2015; for Taiwan Pat. App. No. 101132371; 14 pages. |
| Taiwan Claims (English transiation) as filed with Response to Office Action filed May 16, 2014; for Taiwan Pat. App. No. 101132371; 12 pages. |
| Notice of Allowance dated Jun. 11, 2014; from U.S. Appl. No. 13/113/603; 30 pages. |
| PCT Search Report and Written Opinion of the ISA; dated Sep. 6, 2013; for PCT Pat. App. No. PCT/US2012/024426; 11 pages. |
| Allegro Microsystems, Inc.; “High Precision Linear Hall Effect Sensor IC with a Push/Pull, Pulse Width Modulated Output;” A1351; pp. 1-23. |
| Allegro Microsystems, Inc.; “High Precision 2-Wire Linear Hall Effect Sensor IC with a Pulse Width Modulated Output;” A1354; pp. 1-22. |
| Allegro Microsystems, Inc.; “High Precision Linear Hall-Effect Sensor with an Open Drain Pulse Width Modulated Output;” A1356; pp. 1-20. |
| Allegro Microsystems, Inc.; “Low-Noise Programmable Linear Hall Effect Sensor ICs with Adjustable Bandwidth (50 kHz Maximum) and Analog Output;” A1360, A1361 and A1362; pp. 1-25. |
| Baschirotto et al.; “Development and Analysis of a PCB Vector 2-D Magnetic Field Sensor System for Electronic Compasses;” IEEE Sensors Journal, vol. 6, No. 2; Apr. 2006; pp. 365-371. |
| Kejik, et al.; “Purley CMOS Angular Position Sensor Based on a New Hall Microchip;” 34th Annual Conference of IEEE Industrial Electronics; IECON; Nov. 10-13, 2008; pp. 1777-1781. |
| Kejik,.et al.; “Ultra Low-Power Angular Position Sensor for High-Speed Portable Applications;” 2009 IEEE Sensors Conference; Oct. 25-28, 2009; pp. 173-176. |
| Reymond, et al.; “True 2D CMOS Integrated Hall Sensor;” 2007 IEEE Sensors Conference; Oct. 28-31, 2007; pp. 860-863. |
| Gerhauser; “Intelligente 3D-Magnetfeld Snesorik;” Fraunhofer-Institut for Integrierte Schaltungen IIS; www.iis.fraunhofer.de/asic/analog; Oct. 2009; 2 pages. |
| Melexis Microelectronic Integrated Systems; MLX90333; “Triaxis 3D-Joystick Position Sensor;” Data Sheet; Mar. 2009; 43 pages. |
| MEMSIC Corporation; AN-00MM-004; “Electronic Tilt Compensation;” Mar. 2008; 5 pages. |
| MEMSIC Corporation; AN-00MM-003; “Magnetic Sensor Calibration;” Mar. 2008; 5 pages. |
| MEMSIC Corporation; AN-00MM-002; “Magnetometer Soldering Methodology;” Jun. 2008; 2 pages. |
| MEMSIC Corporation; AN-00MM-001; “Magnetometer Fundamentals;” Jun. 2008; 6 pages. |
| MEMSIC Corporation; AN-00MM-005; “Magnetic Sensor Placement Guidelines;” Oct. 2008; 2 pages. |
| MEMSIC Corporation; MMC312xMQ; “Tri-axis Magnetic Sensor, with I2C Interface;” Aug. 14, 2008; 9 pages. |
| MEMSIC Corporation; MMC314xMS; “Ultra Small 3-axis Magnetic Sensor, with I2C Interface;” Mar. 31, 2010; 8 pages. |
| Micronas GmbH; “HAL® 3625 Programmable Direct Angle Sensor;” Product Information; Sep. 2009; 2 pages. |
| Final Office Action dated Oct. 30, 2013; for U.S. Appl. No. 13/035,257; 21 pages. |
| Petrie; “Circuit and Method for Processing Signals Generated by a Plurality of Sensors;” U.S. Appl. No. 13/035,257, filed Feb. 25, 2011; 52 pages. |
| Petrie; “Circuits and Methods for Processing a Signal Generated by a Plurality of Measuring Devices;” U.S. Appl. No. 13/113,603, filed May 23, 2011; 59 pages. |
| Petrie; “Circular Vertical Hall Mangetic Field Sensing Element and Method With a Plurality of Continuous Output Signals;” U.S. Appl. No. 13/035,243, filed Feb. 25, 2011; 56 pages. |
| PCT International Preliminary Report on Patentability and Written Opinion of the ISA dated Dec. 5, 2013; for PCT Pat. App. No. PCT/US2012/034892; 10 pages. |
| PCT Invitation to Pay Additional Fees with Partial Search Report; dated Feb. 6, 2013; for PCT Pat. App. No. PCT/US2012/052639; 7 pages. |
| Kaufmann et al.; “Novel Coupling Concept for Five-Contact Vertical Hall Devices;” 16th International Solid-State Sensors, Actuators and Microsystems (Transducers) Conference; Jun. 5-9, 2011; 4 sheets. |
| PCT International Preliminary Report on Patentability and Written Opinion of the ISA dated Apr. 10, 2014; for PCT Pat. App. No. PCT/US2012/052639; 19 pages. |
| PCT Search Report and Written Opinion of the ISA; dated May 7, 2012; for PCT Pat. App. No. PCT/US2012/024426; 12 pages. |
| Banjevic; “High Bandwidth CMOS Magnetic Sensors Based on the Miniaturized Circular Vertical Hall Device;” Sep. 2011; 153 pages. |
| Melexis MLX 90324; ““Under-the-Hood” Triaxis Rotary Position feat. SENT Protocol;” 3901090324 Data Sheet; Dec. 2008; 40 pages. |
| Response to Office Action dated Oct. 9, 2013 as filed on Feb. 10, 2014 for U.S. Appl. No. 13/113,603. |
| Office Action dated Jun. 3, 2013; for U.S. Appl. No. 13/035,257; 25 pages. |
| PCT Search Report and Written Opinion of the ISA; dated May 21, 2013; for PCT Pat. App. No. PCT/US2012/052639; 25 pages. |
| Email from Taiwan International Patent & Law Office dated Sep. 2, 2014; for Taiwan Pat. App. No. 101132371; 2 pages. |
| Taiwan Allowance Decision dated Aug. 27, 2014; for Taiwan Pat. App. No. 101132371; 2 pages. |
| Office Action; dated Oct. 9, 2013; for U.S. Appl. No. 13/113,603; 33 pages. |
| PCT Search Report and Written Opinion; dated Nov. 26, 2012; for PCT Pat. App. No. PCT/US2012/034892; 13 pages. |
| Response filed Aug. 20, 2013; to Office Action dated Jun. 3, 2013; for U.S. Appl. No. 13/035,257; 13 pages. |
| Allegro Microsystems, Inc.; “A1140/41/42/43 Data Sheet: Sensitive Two-Wire Chopper-Stabilized Unipolar Hall-Effect Switches;” published Sep. 9, 2004; pp. 1-11. |
| Allegro Microsystems, Inc.; “A1174 Data Sheet: Ultrasensitive Hall Effect Latch with Internally or Externally Controlled Sample and Sleep Periods for Track Ball and Scroll Wheel Applications;” published Jul. 25, 2008; pp. 1-13. |
| Allegro Microsystems, Inc.; “A1230 Data Sheet: Ultra-Sensitive Dual-Channel Quadrature Hall-Effect Bipolar Switch;” published Mar. 26, 2010; 16 sheets. |
| Allegro Microsystems, Inc.; “A1351 Data Sheet: High Precision Linear Hall Effect Sensor with a Push/Pull, Pulse Width Modulated Output;” published Mar. 7, 2008; pp. 1-23. |
| Allegro Microsystems, Inc.; “A1360, A1361 and A1362 Data Sheet: Low-Noise Programmable Linear Hall Effect Sensors with Adjustable Bandwidth (50 kHz Maximum) and Analog Output;” published Mar. 18, 2008; pp. 1-25. |
| Allegro Microsystems, Inc.; “A3212 Data Sheet: Micropower, Ultra-Sensitive Hall-Effect Switch;” published Sep. 22, 2004; pp. 1-12. |
| Allegro Microsystems, Inc.; “ATS675LSE Data Sheet: Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications;” published Jul. 11, 2008; pp. 1-13. |
| Allegro Microsystems, Inc.; “27701-AN Data Sheet: Hall-Effect IC Applications Guide;” Application Information, Rev. 2; http://www.allegromicro.com/en/products/design/hall-effect-sensor-ic-applications-guide/AN27701.pdf; downloaded Sep. 29, 2010; pp. 1-40. |
| Allegro Microsystems, Inc.; “3235 Data Sheet 27633A, Dual-Output Hall-Effect Switch;” http://www.datasheetcatalog.org/datasheets/90/205047—DS.pdf; downloaded Sep. 29, 2010; 6 sheets. |
| Allegro Microsystems, Inc.; “A3425 Data Sheet: Dual, Chopper-Stabilized, Ultra-Sensitive Bipolar Hall-Effect Switch;” published Jun. 28, 2002; pp. 1-10. |
| Atherton et al.; “Sensor Signal Conditioning—an IC Designer's Perspective;” IEEE Electro International; Apr. 26-28, 1991; pp. 129-134. |
| Austria Microsystems; “AS5040 datasheet; 10-Bit Programmable Magnetic Rotary Encoder;” Revision 1.1; Jan. 2004; pp. 1-20. |
| Banjevic et al; “2D CMOS Integrated Magnetometer Based on the Miniaturized Circular Vertical Hall Device;” International Solid-State Sensors, Actuators and Microsystems Conference; Transducers; Jun. 21-25, 2009; pp. 877-880. |
| Blanchard et al.; “Cylindrical Hall Device;” International Electron Devices Meeting; Dec. 8-11, 1996; pp. 541-544. |
| Burger et al.; “New fully integrated 3-D silicon Hall sensor for precise angular-position measurements;” Sensors and Actuators, A 67; May 1998; pp. 72-76. |
| Dwyer; Allegro Microsystems, Inc.; “AN296061 Data Sheet: Ring Magnet Speed Sensing for Electronic Power Steering;” published Jul. 21, 2009; pp. 1-4. |
| Freitas et al.; “Giant magnetoresistive sensors for rotational speed control;” Jorunal of Applied Physics, vol. 85, No. 8; Apr. 15, 1999; pp. 5459-5461. |
| Gilbert; “Technical Advances in Hall-Effect Sensing;” Allegro Microsystems, Inc. Product Description; May 10, 2008; 7 sheets. |
| Häberli et al.; “Contactless Angle Measurements by CMOS Magnetic Sensor with On Chip Read-Out Circuit;” The 8th International Conference on Solid-State Sensors and Actuators and Eurosensors IX; Jan. 25-29, 1995; pp. 134-137. |
| Häberli et al.; “Two-Dimensional Magnetic Microsensor with On-Chip Signal Processing for Contactless Angle Measurement;” IEEE Journal of Solid-State Circuits, vol. 31, No. 12; Dec. 1996; pp. 1902-1907. |
| Hiligsmann et al.; “Monolithic 360 Degrees Rotary Position Sensor IC;” 2004 IEEE Proceedings of Sensors, vol. 3; Oct. 24-27, 2004; pp. 1137-1142. |
| Kejik et al.; “Circular Hall Transducer for Angular Position Sensing;” International Solid-State Sensors, Actuators and Microsystems Conference; Transducers; Jun. 2007; pp. 2593-2596. |
| Lou Law; “Angle Position Sensing with 2-Axis Hall ICs;” Sensors Magazine, vol. 20, No. 3; Mar. 2003; 7 sheets. |
| Masson et al.; “Multiturn and high precision through-shaft magnetic sensors;” Sensor + Text Conference; Proceedings II; May 2009; pp. 41-46. |
| Metz et al.; “Contactless Angle Measurement Using Four Hall Devices on Single Chip;”; International Conference on Solid State Sensors and Actuators; Transducers; vol. 1; Jun. 16-19, 1997; pp. 385-388. |
| Munter; “A Low-offset Spinning-current Hall Plate;” Sensors and Actuators, vol. A21-A23; Jan. 1990; pp. 743-746. |
| Novotechnik Siedle Group; “How New Angular Positioning Sensor Technology Opens a Broad Range of New Applications;” Vert-X Technology; Dec. 2001; pp. 1-5. |
| Paranjape et al.; “A CMOS-compatible 2-D vertical Hall magnetic-field sensor using active carrier confinement and post-process micromachining;” The 8th International Conference on Solid-State Sensors and Acutators, Physical vol. 53, Issues 1-3; May 1996; pp. 278-283. |
| Petoussis et al.; “A Novel Hall Effect Sensor Using Elaborate Offset Cancellation Method;” Sensors & Transducers Journal, vol. 100, Issue 1; Jan. 2009; pp. 85-91. |
| Popovic; “Not-plate-like Hall magnetic sensors and their applications;” Sensors and Actuators A: Physical, vol. 85, Issues 1-3; Aug. 2000; pp. 9-17. |
| Roumenin et al.; “Vertical Hall Effect Devices in the Basis of Smart Silicon Sensors;” IEEE Workshop on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications; Sep. 5-7, 2005; pp. 55-58. |
| Roumenin; “Magnetic sensors continue to advance towards perfection;” Sensors and Actuators A: Physical, vol. 46-47, Issues 1-3; Jan.-Feb. 1995; pp. 273-279. |
| Schneider et al.; “Temperature Calibration of CMOS Magnetic Vector Probe for Contactless Angle Measurement System;” International Electron Devices Meeting; Dec. 8-11, 1996; pp. 533-536. |
| SENSIMA technology sa; “CVHD: a new concept of Angular Position Sensor;” Slide Presentation for Allegro Microsystems; Mar. 2009; 17 sheets. |
| Sentron; AN-101; “Angular position sensing with 2-Axis Hall IC 2SA-10;” Feb. 12, 2004; http://www.diegm.uniud.it/petrella/Azionamenti%20Elettrici%20II/Sensori%20e%20trasduttori/Data%20Sheet%20-%202SA-10.pdf; pp. 1-7. |
| van der Meer; et al; “CMOS quad spinning-current Hall-sensor system for compass application;” IEEE Proceedings of Sensors, vol. 3; Oct. 24-27, 2004; pp. 1434-1437. |
| Vogelgesang et al.; Robert Bosch GmbH; “GMR sensors in automotive application;” CS-SNS/ECS Slides Presentation; Mar. 2, 2005; 16 sheets. |
| Voider; “The CORDIC Trigonometric Computing Technique;” The Institute of Radio Engineers, Inc.; IRE Transactions on Electronic Computers, vol. EC, Issue 3; Sep. 1959; pp. 226-230. |
| Number | Date | Country | |
|---|---|---|---|
| 20130080087 A1 | Mar 2013 | US |
