Multi-turn magnetic sensing with mid-range reset and / or rollover counting

Abstract

To provide multi-turn magnetic sensing systems and related methods.SOLUTION: A system provided herein may include a first multi-turn magnetic sensor and a second multi-turn magnetic sensor, where domain walls propagate in an opposite direction in the second multi-turn magnetic sensor relative to the first multi-turn magnetic sensor in response to a magnetic field. A decoder can output a turn count based on states of the first and second multi-turn sensors. The first and second multi-turn sensors can have a reset state corresponding to the turn count having a value between minimum and maximum values of a counting range relative to the reset state.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The disclosed technology relates to multi-turn magnetic sensors and related systems and methods. [Background technology]

[0002] The magnetic sensing system may include a multi-turn magnetic sensor that counts a cumulative number of rotations of a magnetic field. The multi-turn magnetic sensor may include magnetoresistance elements arranged in series with one another as a helical shaped strip. A resistance of one or more of the magnetoresistance elements may change in response to a rotation of the magnetic field. A state of the multi-turn magnetic sensor may be decoded from an output signal of the multi-turn magnetic sensor. Summary of the Invention [Means for solving the problem]

[0003] The innovations described in the claims each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the claims, some prominent features of the disclosure will now be discussed briefly.

[0004] One aspect of the disclosure is a multi-turn magnetic sensing system including a first multi-turn magnetic sensor, a second multi-turn magnetic sensor, and a decoder configured to output a turn count based on output signals from the first multi-turn sensor and the second multi-turn sensor, wherein a domain wall propagates in an opposite direction in the second multi-turn magnetic sensor relative to the first multi-turn magnetic sensor in response to a magnetic field.

[0005] The decoder can determine a turn count within a range from a first value to a second value for the state of the first and second multi-turn sensors relative to the reset state, the turn count for the reset state being between the first and second values. The first and second multi-turn sensors can each count the same number of turns in opposite directions, and the turn count for the reset state can be a midpoint between the first and second values. The first and second multi-turn sensors can each be filled with domain walls in the reset state.

[0006] The decoder can determine the turn count for two or more complete clockwise rotations of the magnetic field from the reset state, and can determine the turn count for two or more complete counterclockwise rotations of the magnetic field from the reset state.

[0007] The multi-turn magnetic sensing system may include a magnetic reset configured to magnetically reset the first and second multi-turn magnetic sensors to a reset state. The decoder may determine a turn count that is within a range from a first value to a second value for the reset state. The turn count for the reset state may be between the first and second values. In a particular embodiment, the magnetic reset may include a coil configured to apply a reset magnetic field to reset the first and second multi-turn magnetic sensors to the reset state. The multi-turn magnetic sensing system may include a memory for storing an index value. The multi-turn magnetic sensing system may update the index value in association with magnetically resetting the first and second multi-turn magnetic sensors. The decoder may generate the turn count based on the index value and the output signals from the first and second multi-turn sensors.

[0008] When operating in a balanced state, the multi-turn sensing system may operate in a subset of valid states of the first and second multi-turn magnetic sensors.

[0009] The first and second multi-turn sensors may have a state corresponding to the same number of turns as the reset state, and the first and second multi-turn sensors may not be configured to move from that state to the reset state by rotation of the magnetic field.

[0010] The turn count may have the same value for at least two different states of the first and second multi-turn sensors.

[0011] The multi-turn magnetic sensing system can include an angle sensor and a processing circuit configured to output a position measurement. The position measurement can be based on a turn count and an angle, the angle being based on an output signal of the angle sensor.

[0012] Another aspect of the disclosure is a multi-turn magnetic sensing system with a mid-range reset. The multi-turn magnetic sensing system includes a first multi-turn magnetic sensor, a second multi-turn magnetic sensor, and a decoder configured to output a turn count associated with a state of the first multi-turn sensor and the second multi-turn sensor. A domain wall propagates in opposite directions in the second multi-turn magnetic sensor and the first multi-turn magnetic sensor in response to a magnetic field. The turn count is in a range from a minimum value to a maximum value for the reset state. The turn count for the reset state is between a first value and a second value.

[0013] The multi-turn magnetic sensing system can include a magnetic reset configured to magnetically reset the first and second multi-turn magnetic sensors to a reset state.

[0014] Another aspect of the disclosure is a method of multi-turn magnetic sensing with a mid-range reset, the method including resetting a first multi-turn sensor and a second multi-turn sensor to a reset state, where domain walls propagate in opposite directions in the first multi-turn sensor and the second multi-turn sensor in response to a rotation of the magnetic field, detecting a first non-zero number of turns of the magnetic field from the reset state based on reading a first value from the first multi-turn sensor and the second multi-turn sensor, the first non-zero number of turns representing a cumulative rotation of the magnetic field is in a clockwise direction from the reset state, and detecting a second non-zero number of turns of the magnetic field relative to the reset state based on reading a second value from the first multi-turn sensor and the second multi-turn sensor, the second non-zero number of turns representing a cumulative rotation of the magnetic field is in a counterclockwise direction from the reset state.

[0015] The method may include generating a position measurement based on the turn count and the angle information.

[0016] The first multi-turn sensor and the second multi-turn sensor may each include a magnetic spiral having the same number of turns.

[0017] The first multi-turn sensor and the second multi-turn sensor may each be filled with a domain wall in a reset state.

[0018] The method may include magnetically resetting a first multi-turn sensor in response to the magnetic field rotating a particular number of turns, updating an index value stored in memory in association with the magnetic resetting, and determining a turn count based on the index value after the magnetic field update and additional rotation, and reading a third value from the first multi-turn sensor and the second multi-turn sensor.

[0019] The method can include generating a position measurement based on turn count and angle information associated with the magnetic field.

[0020] Another aspect of the disclosure is a method of multi-turn magnetic sensing with rollover count, the method including resetting a multi-turn magnetic sensor to a reset state, the multi-turn magnetic sensor including a magnetic spiral having N turns, where N is a positive integer greater than 1, updating an index value associated with the resetting, and determining a turn count based on an output signal from the multi-turn magnetic sensor and the index value, the turn count having a value having a magnitude greater than N.

[0021] Resetting can include applying a reset magnetic field to the multi-turn magnetic sensor using a coil. Resetting can include moving a permanent magnet into proximity with the multi-turn magnetic sensor.

[0022] Determining the turn count can also be based on an output signal from a second multi-turn magnetic sensor, where the domain walls propagate in an opposite direction in the second multi-turn magnetic sensor compared to the multi-turn magnetic sensor. The method can include generating a turn count having a second value after an additional rotation of the magnetic field following the determining, where the value represents a clockwise rotation from the initialized state and the second value represents a counterclockwise rotation from the initialized state. The multi-turn sensor and the second multi-turn sensor can each be filled with domain walls in the reset state.

[0023] The turn count may have a quarter turn resolution.

[0024] The method may include processing an output signal from the angle sensor to generate angle information, and generating a position measurement based on the turn count and the angle information.

[0025] Another aspect of the disclosure is a multi-turn magnetic sensing system having a rollover count. The multi-turn magnetic sensing system includes a multi-turn magnetic sensor and a processing circuit. The multi-turn magnetic sensor includes a magnetic spiral having N turns, where N is a positive integer greater than 1. The processing circuit includes a memory configured to store an index value and a decoder configured to determine a turn count having a value having a magnitude greater than N based on an output signal from the multi-turn magnetic sensor and the index value. The turn count represents a number of rotations of a magnetic field.

[0026] The multi-turn magnetic sensing system can include a magnetic reset configured to magnetically reset the magnetic spiral. The magnetic reset comprises a coil configured to apply a reset magnetic field to magnetically reset the magnetic spiral in response to a control signal from a processing circuit. The processing circuit can update an index value in association with magnetically resetting the magnetic spiral. The processing circuit can update the index value in response to detecting a rotation of the magnetic field after magnetically resetting the magnetic spiral.

[0027] The multi-turn magnetic sensing system may include a second multi-turn magnetic sensor including a second magnetic spiral. The magnetic domain walls may propagate in opposite directions in the magnetic spiral and the second magnetic spiral. The decoder may determine a turn count based on an output signal from the multi-turn magnetic sensor, an output signal from the second multi-turn magnetic sensor, and an index value. The second magnetic spiral may have N turns. The processing circuitry may detect a change in the direction of rotation of the magnetic field. The decoder may determine a turn count at a second value having a magnitude greater than N, the value representing a clockwise rotation from an initialization state, and the second value representing a counterclockwise rotation from an initialization state.

[0028] The multi-turn magnetic sensing system can include an angle sensor, and the processing circuit can output a position measurement based on the turn count and the angle information from the angle sensor.

[0029] Another aspect of the disclosure is a multi-turn magnetic sensing system with rollover count. The multi-turn magnetic sensing system includes a first multi-turn magnetic sensor, a second multi-turn magnetic sensor, and a decoder configured to output a turn count based on an index value and a state of the first multi-turn sensor and the second multi-turn sensor. The first multi-turn magnetic sensor includes a first magnetic spiral having N turns, where N is a positive integer greater than 1. Domain walls propagate in opposite directions in the second multi-turn magnetic sensor and the first multi-turn magnetic sensor in response to a magnetic field. The decoder is configured to determine a turn count for more than N complete clockwise rotations of the magnetic field from an initialization state, and to determine a turn count for more than N complete counterclockwise rotations of the magnetic field from an initialization state.

[0030] The multi-turn magnetic sensing system can include a magnetic reset configured to magnetically reset the first multi-turn magnetic sensor to a reset state. The multi-turn magnetic sensing system can include a processing circuit configured to update the index value in association with magnetically resetting the first multi-turn magnetic sensor.

[0031] For purposes of summarizing the disclosure, certain aspects, advantages, and novel features of the invention have been described herein. It is to be understood that not all such advantages may necessarily be achieved in accordance with any particular embodiment. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein, without necessarily achieving other advantages that may be taught or suggested herein. [Brief description of the drawings]

[0032] Embodiments of the present disclosure may be described, by way of non-limiting example, with reference to the accompanying drawings, in which: [Figure 1A] FIG. 2 is a schematic diagram of two multi-turn sensors of a multi-turn magnetic sensing system, according to an embodiment. [Figure 1B] 1B is a table summarizing the states and turn counts for the multi-turn magnetic sensing system of FIG. 1A as the magnetic field rotates. [Diagram 2] FIG. 1 is a schematic block diagram of a multi-turn magnetic sensing system with mid-position reset, according to an embodiment. [Diagram 3] FIG. 1 is a schematic block diagram of a multi-turn magnetic sensing system that also includes angle sensing, according to one embodiment. [Figure 4] FIG. 1 is a schematic block diagram of a multi-turn magnetic sensing system that also includes quadrant detection, according to an embodiment. [Figure 5A] FIG. 2 is a schematic diagram of two multi-turn sensors of a multi-turn magnetic sensing system, according to an embodiment. [Figure 5B-1] 5B is a table summarizing the sensor state, index value, and turn count for the multi-turn magnetic sensing system of FIG. 5A as the magnetic field rotates, the multi-turn magnetic sensor is reset, and the index value is updated. [Figure 5B-2] 5B is a table summarizing the sensor state, index value, and turn count for the multi-turn magnetic sensing system of FIG. 5A as the magnetic field rotates, the multi-turn magnetic sensor is reset, and the index value is updated. [Figure 5B-3] 5B is a table summarizing the sensor state, index value, and turn count for the multi-turn magnetic sensing system of FIG. 5A as the magnetic field rotates, the multi-turn magnetic sensor is reset, and the index value is updated. [Figure 6] FIG. 1 is a schematic block diagram of a multi-turn magnetic sensing system with rollover counting, according to an embodiment. [Figure 7]FIG. 1 is a schematic block diagram of a multi-turn magnetic sensing system with rollover counting and angle sensing, according to an embodiment. [Figure 8] FIG. 1 is a schematic block diagram of a multi-turn magnetic sensing system having rollover counting and a single multi-turn magnetic sensor embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the invention described herein may be embodied in many different ways, for example, as defined and covered by the claims. In this description, reference is made to the drawings, where like reference numbers may indicate identical or functionally similar elements. It should be understood that the elements illustrated in the drawings are not necessarily drawn to scale. It should also be understood that certain embodiments may include more elements and / or a subset of the illustrated elements illustrated in the drawings. Furthermore, some embodiments may incorporate features of any suitable combination from two or more drawings. Headings are provided for convenience only and do not affect the scope or meaning of the claims.

[0034] Multi-turn magnetic sensor The multi-turn magnetic sensor can continuously detect rotational or linear motion in the absence of power, and absolute position can be read upon power-up. The multi-turn magnetic sensor can provide true power-on functionality without receiving electrical power. The multi-turn magnetic sensor can operate on the principle of a magnetic spiral or tracker that detects motion in the presence of a moving permanent magnet. The magnetic spiral can include nanowires. The magnetic spiral can include giant magnetoresistance (GMR) material. The resistance of the magnetoresistance element of the magnetic spiral can change in response to a rotation of a magnetic field as the magnetic spiral fills with magnetic domain walls, which can also be referred to as magnetic domains. This effect can be referred to as morphological anisotropy. The turn count can be decoded from the resistance of the magnetoresistance element of the multi-turn magnetic sensor. The turn count can be combined with the angle detected by the angle sensor to provide absolute multi-turn position information.

[0035] A technical challenge for multi-turn magnetic sensors is initializing and / or resetting the multi-turn magnetic sensor at intermediate positions in its measurement range. The present disclosure provides a technical solution to this challenge.

[0036] Another technical challenge associated with multi-turn magnetic sensors is that the number of turns that a multi-turn sensor counts may be limited by the number of turns of the magnetic spiral of the multi-turn magnetic sensor. In various applications, it may be desirable for a multi-turn magnetic sensor to continue counting beyond a turn count limit that is based on the physical geometry of the magnetic spiral. The present disclosure provides a technical solution for counting turns of a magnetic field beyond the limits that may be imposed by the physical geometry of the magnetic spiral of a multi-turn magnetic sensor.

[0037] Resetting a multi-turn magnetic sensor A multi-turn magnetic sensor can be reset by applying a magnetic field having a magnitude higher than the upper magnetic operating limit of the multi-turn magnetic sensor. This can result in the magnetic spiral of the multi-turn magnetic sensor being filled with domain walls. Such a reset can correspond to the multi-turn magnetic sensor being in a maximum turn count state. In some other applications, resetting the magnetic spiral of the multi-turn magnetic sensor can result in the multi-turn magnetic sensor being in a minimum turn count with the magnetic spiral emptying the domain walls.

[0038] The magnetic spiral can take the form of a clockwise (CW) sensor or a counterclockwise (CCW) sensor. A CW multi-turn magnetic sensor can count turns in the presence of a magnetic field rotating in a CW direction. In such a multi-turn magnetic sensor, the turn count can correspond to a magnetoresistive element of the magnetic spiral being filled with a domain wall. The magnetoresistive element can be a leg of the magnetic spiral. A CCW multi-turn magnetic sensor can count turns in the presence of a magnetic field rotating in a CCW direction. The domain walls propagate in the opposite direction in a CW multi-turn magnetic sensor relative to a CCW multi-turn magnetic sensor.

[0039] When a CW sensor is magnetically reset by being filled with domain walls, the CW sensor may be in a state corresponding to a maximum turn count. From the state corresponding to a maximum turn count, the CW sensor can detect multi-turn motion only in the presence of a magnetic field rotating in the CCW direction. Similarly, after a CCW sensor is magnetically reset to a state filled with domain walls, the CCW sensor can detect multi-turn motion only in the presence of a magnetic field rotating in the CW direction.

[0040] Intermediate position reset for multi-turn magnetic sensors Aspects of the disclosure relate to resetting a multi-turn magnetic sensor to a reset state corresponding to a turn count that is between a first value and a second value of a turn count range corresponding to two multi-turn magnetic sensor states. The first value can be a minimum value of the turn count range and the second value can be a maximum value of the turn count range. Thus, the multi-turn magnetic sensing system can track a CW rotation of the magnetic field from the reset state and track a CCW rotation of the magnetic field from the reset state.

[0041] The multi-turn magnetic sensing system may include two multi-turn magnetic sensors, one CW multi-turn magnetic sensor, and one CCW multi-turn magnetic sensor. The domain walls may propagate in opposite directions in the CW multi-turn magnetic sensor and the CCW multi-turn magnetic sensor. Both the CW multi-turn magnetic sensor and the CCW multi-turn magnetic sensor may be reset to a reset state in an initialization phase. The reset state may correspond to both multi-turn magnetic sensors being filled with domain walls.

[0042] From the reset state, the multi-turn magnetic sensing system can count the cumulative number of turns in the CW and / or CCW directions. If the magnetic field rotates in the CW direction from the reset state, then the CCW sensor counts down from N to 0, where N is the maximum number of turns. At the same time, the CW sensor can remain in the maximum N turns state. Similarly, if the magnetic field rotates in the CCW direction from the reset state, then the CW sensor can count down from N to 0, where N is the maximum number of turns. At the same time, the CCW sensor can remain in the maximum N turns state.

[0043] FIG 1A is a schematic diagram of two multi-turn sensors of a multi-turn magnetic sensing system, according to an embodiment. FIG 1B is a table summarizing the states and turn counts for the multi-turn magnetic sensing system of FIG 1A as the magnetic field rotates. FIG 1A illustrates a multi-turn magnetic sensing system 10 having a CW sensor, and a CCW sensor with magnetic reset capability can measure + / - N turns of a rotating magnetic field with a mid-range magnetic reset.

[0044] Referring to FIG. 1A, a multi-turn magnetic sensing system 10 includes a first magnetic spiral 12 and a second magnetic spiral 14. The magnetic spirals 12 and 14 each implement a respective multi-turn magnetic sensor. The magnetic spirals 12 and 14 each include a plurality of magnetoresistance elements 15 arranged in series with each other. Each side of the magnetic spirals 12, 14 between successive corners of the magnetic spirals 12, 14 includes a magnetoresistance element 15. The magnetic spirals 12 and 14 each include 6 turns and 24 magnetoresistance elements 15. The magnetic spirals 12 and 14 can each include a domain wall generator 16 at the end of the spiral. In certain applications, the first magnetic spiral 12 and the second magnetic spiral 14 can be on a single die. Alternatively, the first magnetic spiral 12 and the second magnetic spiral 14 can be on different dies.

[0045] The multi-turn magnetic sensing system 10 can count + / -3 turns of the magnetic field from a reset state. The reset state can correspond to a turn count that is between the end points of the counting range. For example, in the multi-turn magnetic sensing system 10, the reset state can correspond to the midpoint of the counting range. For a + / -3 counting range, the first magnetic spiral 12 and the second magnetic spiral 14 can each have a measurement range of 6 turns. For example, as illustrated in FIG. 1A, the first magnetic spiral 12 can count 6 turns of the magnetic field in a CW direction, and the second magnetic spiral 14 can count 6 turns of the magnetic field in a CCW direction. In the multi-turn magnetic sensing system 10, the reset state can correspond to the midpoint of the turn counting range. This can be due to the first magnetic spiral 12 and the second magnetic spiral 14 having the same number of turns.

[0046] In this disclosure, CW turns are designated as positive turns and CCW turns are designated as negative turns. The same functions can be described using the opposite convention, where CCW turns are positive turns and CW turns are negative turns.

[0047] The operation of the multi-turn magnetic sensing system 10 may be considered with reference to FIG. 1B. The first magnetic spiral 12 and the second magnetic spiral 14 may be reset. This may fill each of the magnetic spirals 12, 14 with domain walls. In the reset state, both the first magnetic spiral 12 and the second magnetic spiral 14 may be in a maximum state, which is 6 in this example. The turn count of the multi-turn magnetic sensing system 10 may represent the cumulative number of turns from the reset state. Thus, for the reset state, the turn count is 0. This state may be system state A of the multi-turn magnetic sensing system 10.

[0048] As the magnetic field rotates CW for three full turns, the turn count of the second magnetic spiral 14 may decrease and the state of the first magnetic spiral 12 may remain the same. The turn count of the multi-turn magnetic sensing system 10 may increase by one for each full CW rotation of the magnetic field. The states of the multi-turn magnetic sensing system 10 after one full CW rotation from the reset state, one full CW rotation from the reset state, and three full CW rotations from the reset state are B, C, and D in FIG. 1B, respectively.

[0049] As the magnetic field rotates CW for three full turns, the turn count of the second magnetic spiral 14 may decrease and the turn count of the first magnetic spiral 12 may remain the same. The turn count of the multi-turn magnetic sensing system 10 may increase by one for each full CW rotation of the magnetic field. The states of the multi-turn magnetic sensing system 10 after one full CW rotation from the reset state, one full CW rotation from the reset state, and three full CW rotations from the reset state are B, C, and D in FIG. 1B, respectively.

[0050] From system state D, the magnetic field may rotate three full CCW turns. The turn count of the first magnetic spiral 12 may decrease and the turn count of the second magnetic spiral 14 may increase. The turn count of the multi-turn magnetic sensing system 10 may decrease by one for each full CCW rotation of the magnetic field. The states of the multi-turn magnetic sensing system 10 after these full CCW magnetic field rotations from system state D are E, F, and G, respectively. In system state G, after 3 CW and 3 CCW rotations from the reset state, the turn count of the system returns to 0.

[0051] The magnetic field may rotate CW for an additional three full turns, where the first magnetic spiral 12 may decrease and the turn count of the second magnetic spiral 14 may increase.

[0052] After the magnetic field has rotated cumulatively three turns in each direction from the reset state, the multi-turn magnetic sensing system 10 can operate in an equilibrium state. The first system state K and subsequent states in FIG. 1B correspond to the multi-turn magnetic sensing system 10 operating in an equilibrium state. Once equilibrium is reached, the multi-turn magnetic sensing system 10 operates in one of seven system states for every turn of the magnetic field, which correspond to a total turn count of -3 to +3. These seven system states are states J, K, L, M, N, O, and P in FIG. 1B. A pre-processing circuit and decoder can be used to decode the valid pre-equilibrium states into turn counts. In FIG. 1B, states A, B, C, D, E, F, G, H, and I are valid pre-equilibrium states from which the turn count of the system can be decoded.

[0053] 1B, the multi-turn magnetic sensing system 10 can have two or more system states corresponding to the same turn count. For example, there can be a pre-equilibrium state and an equilibrium state that both correspond to the same turn count. As an example, system states H and L both correspond to a turn count of -1. As another example, system states B, F, and N each correspond to a turn count of 1. This example illustrates that two or more pre-equilibrium states can correspond to the same turn count as one equilibrium state.

[0054] 1B shows 16 system states (i.e., states A-P) corresponding to full turns from the reset state. Other valid states are possible for the multi-turn magnetic sensing system 10. Another valid state may be a pre-balance state. As an example of another valid state, one CCW rotation from the reset state is another possible valid state.

[0055] The operation of the multi-turn magnetic sensing system 10 is discussed above with reference to a full rotation of the magnetic field. The multi-turn magnetic sensing system 10 can track turns with different resolutions according to any suitable principles and advantages disclosed herein. For example, the decoder can determine the turn count from the output signals associated with the first magnetic spiral 12 and / or the second magnetic spiral 14 with half-turn resolution or quarter-turn resolution. With half-turn resolution, there can be an intermediate state between any two consecutive states associated with a full turn, which can correspond to a half-turn between two consecutive full-turn states. With quarter-turn resolution, there can be three intermediate states between any two consecutive states associated with a full turn, which can correspond to a quarter-turn, a half-turn, and three-quarter-turn.

[0056] Any of the suitable principles and advantages disclosed with reference to Figures 1A and / or 1B may be applied to a multi-turn magnetic sensing system capable of counting + / -N turns, where the CW and CCW sensors each have a measurement range of 2N turns individually. Any of the suitable principles and advantages disclosed with reference to Figures 1A and / or 1B may be applied to a multi-turn magnetic sensing system with rollover counting and indexing, where the turn count can have a value having a magnitude greater than the number of turns of an individual multi-turn magnetic sensor.

[0057] Although magnetic spirals 12 and 14 are configured to count the same number of turns as each other, any of the suitable principles and advantages disclosed with reference to Figures 1A and / or 1B may be applied to two magnetic spirals capable of counting different numbers of turns, in which case the reset state may not be at the exact midpoint of the system turn count range.

[0058] Multi-turn magnetic sensing system with intermediate position reset - Patents.com The intermediate position reset can be implemented in various multi-turn magnetic sensing systems. Such multi-turn magnetic sensing systems can include additional hardware compared to that shown in FIG. 1A. For example, the multi-turn magnetic system can include a processing circuit and a magnetic reset. The processing circuit can include a signal conditioning circuit and a controller. In certain applications, the multi-turn magnetic system can include one or more additional sensors, such as an angle sensor and / or a quadrant detector. An exemplary multi-turn magnetic sensing system with intermediate position reset can be discussed with reference to FIGS. 2-4.

[0059] 2 is a schematic block diagram of a multi-turn magnetic sensing system 20, according to an embodiment. The multi-turn magnetic sensing system 20 can track and output a turn count that represents the number of turns of a magnetic field that can be generated by rotation of a magnetic target 21 or other magnetic field source. As illustrated, the magnetic target 21 can be a dipole magnet. The magnetic target 21 can be attached to a rotating shaft in certain applications. The multi-turn magnetic sensing system 20 includes a first multi-turn magnetic sensor 22, a second multi-turn magnetic sensor 24, a signal conditioning circuit 25, a controller 26, and a magnetic reset 27.

[0060] The first multi-turn magnetic sensor 22 is a CW sensor. The second multi-turn magnetic sensor 24 is a CCW sensor. The multi-turn magnetic sensors 22 and 24 can each include a magnetic spiral. An exemplary magnetic spiral is shown in FIG. 1A. The multi-turn magnetic sensors 22 and 24 can include magnetic spirals configured to track any suitable number of turns for a particular application.

[0061] The output signals from the first multi-turn magnetic sensor 22 and the second multi-turn magnetic sensor 24 are conditioned by a signal conditioning circuit 25. The signal conditioning circuit 25 may include any suitable circuitry for modifying the raw analog output signals from the multi-turn magnetic sensors 22 and 24 to make the signals suitable for further processing. The signal conditioning circuit 25 may include, for example, one or more amplifiers and / or one or more filters. The signal conditioning circuit 25 may include a readout circuit 28 that reads out values ​​associated with the magnetoresistance elements of the multi-turn magnetic sensors 22 and 24. In certain applications, the readout circuit 28 may be implemented according to any suitable principles and advantages disclosed in U.S. Pat. No. 10,782,153, the disclosure of which is incorporated herein by reference in its entirety and for all purposes. The signal generated by the readout circuit 28 may be indicative of the resistance of one or more of the magnetoresistance elements of the first multi-turn magnetic sensor 22 or the second multi-turn magnetic sensor 24.

[0062] The controller 26 can include a decoder 29 that can determine the cumulative turn count of the magnetic field from the output signal from the signal conditioning circuitry 25. The controller 26 can digitize the output signal from the signal conditioning circuitry 25 with an analog-to-digital converter (ADC). The digital output signal from the ADC can be provided to the decoder 29 to determine the turn count. The controller 26 can output the turn count to a user interface, for example. The user interface can be implemented using an integrated circuit (IC) 2 The controller 26 may generate a control signal for controlling the magnetic reset 27. The controller 26 may be any suitable interface, including, but not limited to, a serial peripheral interface (SPI) or a serial peripheral interface (C) interface.

[0063] The decoder 29 can output a turn count representing the accumulated number of turns of the magnetic field. The decoder 29 can determine any suitable value, for example, from Table 1B. For example, the decoder 29 can determine the state and turn count of the multi-turn magnetic sensors 22 and 24. The decoder 29 can determine the state of the first multi-turn magnetic sensor 22 and the second multi-turn magnetic sensor 24 based on the output signal from the readout circuit 28. The state of the first multi-turn magnetic sensor 22 can be determined based on a signal representing the resistance of the magnetoresistance element of the first multi-turn magnetic sensor 22. Similarly, the state of the second multi-turn magnetic sensor 24 can be determined based on a signal representing the resistance of the magnetoresistance element of the first multi-turn magnetic sensor 24. The decoder 29 can receive a digital input signal and provide the turn count as a digital output signal. In certain applications, the decoder 29 can implement successive approximation decoding to determine the state of the individual multi-turn magnetic sensors 22 or 24. Such decoding may be implemented in accordance with any suitable principles and advantages disclosed in U.S. Pat. No. 10,830,613, the disclosure of which is incorporated herein by reference in its entirety and for all purposes.

[0064] The decoder 29 can determine the turn count from the states of the multi-turn magnetic sensors 22 and 24. An example mapping of turn count to sensor states is provided in FIG. 1B. In decoding the output signal from the readout circuit 28, the decoder 29 can decode a valid pre-balance state and a valid balance state. The decoder 29 can be a full-turn decoder, a half-turn decoder, or a quarter-turn decoder.

[0065] The controller 26 can control a magnetic reset 27 to reset the multi-turn magnetic sensors 22 and 24 to a reset state. Such a magnetic reset may be performed upon system initialization. In such cases, the reset state may be an initialization state. In some applications, a magnetic reset may be performed in response to one or more of the detection of a system fault, periodically with respect to a rollover count, discussed in more detail below, after reaching a threshold amount of time for system operation, or in response to the detection of any other suitable condition.

[0066] The magnetic reset 27 may include any suitable structure for resetting the multi-turn magnetic sensors 22 and 24. In certain applications, the magnetic reset 27 may include a coil capable of generating a reset magnetic field greater than the upper operating limit of the multi-turn magnetic sensors 22 and 24. The controller 26 may cause a current to flow through the coil to generate the reset magnetic field. The coil may fill the multi-turn magnetic sensors 22 and 24 with magnetic domain walls to place the multi-turn magnetic sensors 22 and 24 in a reset state. The coil may be mounted on a printed circuit board. In some other applications, the magnetic reset 27 may include a permanent magnet that is brought into physical proximity to the multi-turn magnetic sensors 22 and 24 to apply a magnetic field greater than the upper operating limit of the multi-turn magnetic sensors 22 and 24. For such a permanent magnet, the controller 26 may provide a control signal to move the permanent magnet close enough to the multi-turn magnetic sensors 22 and 24 to place them in a reset state. The controller 26 may then move the permanent magnet away from the multi-turn magnetic sensors 22 and 24 to allow the multi-turn magnetic sensing system 20 to track the rotation of the magnetic field.

[0067] Figure 3 is a schematic block diagram of a multi-turn magnetic sensing system 30 including an angle sensor 32, according to an embodiment. The multi-turn magnetic sensing system 30 is similar to the multi-turn magnetic sensing system 20 of Figure 2, except that the multi-turn magnetic sensing system 30 also includes an angle sensor 32, and processing circuitry of the multi-turn magnetic sensing system 30 can combine the angle and turn count to generate a position measurement.

[0068] The angle sensor 32 can detect a magnetic angle associated with the magnetic field. The angle sensor 32 can be a magnetic sensor, such as, but not limited to, an anisotropic magnetoresistive (AMR) sensor or another type of magnetoresistive sensor. As an example, the angle sensor 32 can include two half bridges of magnetoresistive elements. The angle can be determined from the angle sensor 32. For example, the signal conditioning circuit 25 can condition the output signal from the angle sensor 32, and the controller 26 can determine the angle from the conditioned output signal from the angle sensor 32. The angle can be in the range of 0° to 360°. The angle can be determined to any suitable accuracy, such as within 1°, within 0.5°, or within 0.25°.

[0069] The controller 26 can combine the turn count and the angle to generate a position measurement. The position measurement can represent the number of turns and the angle of the magnetic field rotation from a reset state. For example, if the turn count is 2 turns and the angle is 14°, the position measurement can be 734°. The position measurement has a finer resolution than the turn count. In one particular application, the position measurement can have an accuracy of ±0.25°.

[0070] The processing circuitry of the multi-turn magnetic sensing system 30 (e.g., the circuitry of the controller 26) may compensate for the phase shift between the signals associated with the angle sensor and the multi-turn sensor, for example, in accordance with any suitable principles and advantages disclosed in U.S. Pat. No. 10,859,406, the disclosure of which is incorporated herein by reference in its entirety and for all purposes.

[0071] Figure 4 is a schematic block diagram of a multi-turn magnetic sensing system 30 including a quadrant detector 42, according to an embodiment. The multi-turn magnetic sensing system 40 is similar to the multi-turn magnetic sensing system 40 of Figure 3, except that the multi-turn magnetic sensing system 40 also includes a quadrant detector 42, and the processing circuitry of the multi-turn magnetic sensing system 40 can combine the quadrant information with turn count and / or angle information.

[0072] The quadrant detector 42 can detect the quadrant associated with the magnetic field. The angle sensor 42 can be a magnetic sensor, such as, but not limited to, an anisotropic magnetoresistive (AMR) sensor or another type of magnetoresistive sensor. The quadrant can be determined from the quadrant detector 42. For example, the controller 26 can determine the quadrant from an output signal from the quadrant detector 42 conditioned by the signal conditioning circuitry 25. The controller 26 can use the quadrant information to increase safety and / or redundancy. The controller 26 combines the quadrant with the turn count to generate a position measurement and / or to verify the turn count and / or the position measurement. In some cases, a multi-turn magnetic sensing system can include the multi-turn magnetic sensors 22 and 24 and the quadrant detector 42, but not the angle sensor 32.

[0073] Multi-turn magnetic sensing with rollover counting Aspects of the disclosure relate to a rollover count that exceeds a turn count associated with the number of turns of a magnetic tracking of a multi-turn magnetic sensor. In a rollover count, a multi-turn magnetic sensor system can continuously count the number of rotations of a magnetic field beyond a turn count associated with a physical geometry of a multi-turn magnetic sensor of the multi-turn magnetic sensor system. The turn count associated with the physical geometry can be referred to as a sensor turn count. When the multi-turn magnetic sensor reaches a value at an end of a sensor turn count range, the multi-turn magnetic sensor of the system can be reset and an index value can be stored in a memory of the system. In a subsequent decoding of the turn count, the system can determine the turn count based on the state of the multi-turn magnetic sensor and the index value.

[0074] In one particular embodiment, the multi-turn magnetic sensor includes a magnetic spiral having N turns, where N is a positive integer greater than 1. The index value can be updated in association with a reset of the multi-turn magnetic sensor. The turn count can be determined based on an output signal from the multi-turn magnetic sensor and the index value, where the turn count can have a value having a magnitude greater than N. The turn count can also be determined based on an output signal from a second multi-turn magnetic sensor, where the domain walls propagate in an opposite direction in the second multi-turn magnetic sensor compared to the first multi-turn magnetic sensor.

[0075] The ability to continue counting beyond the turn count associated with the physical geometry of the multi-turn magnetic sensor can be achieved by a system including two multi-turn magnetic sensors and a magnetic reset system, where the two multi-turn magnetic sensors include a CW sensor and a CCW sensor. The magnetic reset can be implemented according to any suitable principles and advantages of magnetic reset disclosed herein.

[0076] Both the CW and CCW sensors can be magnetically reset (e.g., filled with domain walls) during an initialization phase. When the magnetic field rotates in the CW direction from the reset state, the CCW sensor can become active and count down from N to 0, where N is the maximum number of turns of the sensor, while the CW sensor can remain in a static state for up to N turns. Similarly, when the magnetic field rotates in the CCW direction from the reset state, the CW sensor can become active and count down from N to 0, where N is the maximum number of turns of the sensor, while the CCW sensor can remain in a static state for up to N turns.

[0077] Applying a magnetic reset whenever the active sensor reaches 0 turns may allow for continuous counting. Following the reset, as rotation continues, the turn count may be indexed up or down, if applicable, as the active sensor state changes from N to N-1. The updated index value may be stored in memory.

[0078] A change in rotation direction can be detected when a static sensor set with N turns changes state. When the static sensor changes stages, the previous static sensor can begin counting down from N to 0 and the previous active sensor can count in the opposite direction.

[0079] Following a change in direction, a magnetic reset may be applied in response to the previously active sensor reaching N turns. After the reset, the index value may be updated in the opposite direction when the state of the newly active sensor changes from N to N-1. The newly active sensor may be reset when it reaches 0 turns.

[0080] FIG 5A is a schematic diagram of two multi-turn sensors of a multi-turn magnetic sensing system, according to an embodiment. FIG 5B-1, FIG 5B-2, and FIG 5B-3 are tables summarizing the sensor state, index value, and turn count for the multi-turn magnetic sensing system of FIG 5A as the magnetic field rotates, the multi-turn magnetic sensors are reset, and the index value is updated. FIG 5A illustrates a multi-turn magnetic sensing system 50 having a 10-turn CW sensor and a 10-turn CCW sensor with magnetic reset capability and index tracking.

[0081] Referring to FIG. 5A, a multi-turn magnetic sensing system 50 includes a first magnetic spiral 52 and a second magnetic spiral 54. The magnetic spirals 52 and 54 each implement a multi-turn magnetic sensor. The magnetic spirals 52 and 54 each include a plurality of magnetoresistance elements 15 arranged in series with each other. Each side of the magnetic spirals 52, 54 between successive corners of the respective magnetic spirals 52, 54 includes a magnetoresistance element 15. The magnetic spirals 52 and 54 include 10 turns and 40 magnetoresistance elements 15, respectively. Any suitable principles and advantages of rollover counting disclosed herein can be applied to magnetic spirals having any suitable number of turns. The magnetic spirals 52 and 54 can each include a domain wall generator 16 at the end of the spiral.

[0082] With magnetic reset and indexing, the multi-turn magnetic sensing system 50 can count rotations of the magnetic field in both the CW and CCW directions beyond the number of turns of the individual magnetic spirals 52, 54. For example, the tables in Figs. 5B-1, 5B-2, and 5B-3 summarize the operation of the multi-turn magnetic sensing system 50 for various rotations of the magnetic field ranging from -23 turns to 27 turns forming an initial state. In this embodiment, the multi-turn magnetic sensing system 50 can track the state of the magnetic spirals 52 and 54 as well as the turn count with an index value. The index value is stored in the memory of the multi-turn magnetic sensing system 50. The multi-turn magnetic sensing system 50 can count any suitable number of turns in the CW direction and any suitable number of turns in the CCW direction.

[0083] As discussed above, in this disclosure, CW turns are designated as positive turns and CCW turns are designated as negative turns. The same functions can be described using the opposite convention, where CCW turns are positive turns and CW turns are negative turns.

[0084] The operation of the multi-turn magnetic sensing system 50 may be discussed with reference to FIGS. 5B-1, 5B-2, and 5B-3. The first magnetic spiral 52 and the second magnetic spiral 54 may be reset to an initialization state. This may fill each of the magnetic spirals 52, 54 with domain walls. In the initialization state, the first magnetic spiral 52 and the second magnetic spiral 54 may both be in a maximum state, which is 10 in this example. The turn count of the multi-turn magnetic sensing system 50 may represent a cumulative number of turns from the initialization state. In the initialization state, the turn count is 0. As shown in FIG. 5B-1, the initialization state corresponds to a turn count of 0. The initialization state also corresponds to an index of 0 in FIG. 5B-1. The index is updated in response to detecting a rotation of the magnetic field from the initialization state. For example, in this example, the index is incremented from 0 to 1 in response to detecting a CW rotation of the magnetic field from the initialization state.

[0085] As the magnetic field rotates CW for 9 full turns, the turn count of the second magnetic spiral 54 may decrease and the state of the first magnetic spiral 52 may remain the same. The turn count of the multi-turn magnetic sensing system 50 may increase by 1 for each full CW rotation of the magnetic field. During this CW rotation, the second magnetic spiral 54 is active and the first magnetic spiral 52 is static.

[0086] The magnetic spiral 54 may be magnetically reset after the magnetic field rotates a full number of CW rotations corresponding to the number of turns of the second magnetic spiral 54. In the multi-turn magnetic sensing system 50, the second magnetic spiral 54 is reset after the magnetic field rotates 10 full turns CW from the reset state. The magnetic spirals 52 and 54 may be reset to a reset state. The reset state may differ from the initialization state due to the index value being non-zero. For example, in the reset state of FIG. 5B-1 corresponding to 10 turns, the magnetic spirals 52 and 54 each have 10 states and the index value is 1. The reset state may be the same as the initialization state when the reset state corresponds to 0 turns. For example, the reset state of FIG. 5B-2 corresponding to 0 turns is the same as the initialization state.

[0087] After the reset, the second magnetic spiral 54 can continue to adjust its turn count and function as an active sensor as the magnetic field rotates in a CW direction. The index value can be adjusted in association with the magnetic reset. The index value can be updated before, during, or after the magnetic reset to keep track of the number of turns associated with the magnetic reset. In certain applications, the index value can be adjusted after the reset. For example, as shown in FIG. 5B-1 and FIG. 5B-2, the index value can be updated corresponding to a full turn after the reset. The index value can be updated corresponding to less than a full turn (e.g., a quarter turn, a half turn, three-quarter turn, etc.) after the reset in various applications. In some other implementations, the index value can be updated before or during the magnetic reset.

[0088] The multi-turn magnetic sensing system 50 can detect a change in the rotation direction of the magnetic field. In response to a change in the rotation direction of the magnetic field, the static sensor can change state and the magnetic spirals 52 and 54 can count in the opposite direction. For example, FIG. 5B-2 shows that the first spiral 52 can transition from a turn count of 10 to a turn count of 9, and the second spiral 54 can transition from a turn count of 3 to a turn count of 4 for a full CCW rotation after the magnetic field rotation direction change. This illustrates that the previous static sensor can become active in conjunction with the change in rotation direction. When both magnetic spirals 52 and 54 have a valid state different from their respective reset states, it can indicate that there is a change in rotation direction within half the number of turns of the magnetic spirals 52 and 54.

[0089] As the magnetic field rotates CCW, the turn count of the first magnetic spiral 52 may decrease and the turn count of the second magnetic spiral 54 may increase. The magnetic spirals 52 and 54 may be reset in conjunction with the CCW rotation of the magnetic field, causing the magnetic spiral 52 or 54 to reach an end point (e.g., 0 or 10 in Figs. 5B-1 to 5B-3) turn count. For example, a magnetic reset may be performed in conjunction with the second magnetic spiral 54 reaching a maximum turn count, which corresponds to the number of turns of the second magnetic spiral 54 in Fig. 5B-2. In some other applications where the magnetic field transitions from rotating CW to rotating CCW and the second spiral has a count closer to the maximum count value than the minimum count value, a magnetic reset may be performed in conjunction with the first magnetic spiral 52 reaching a minimum turn count.

[0090] The index may be updated in association with a magnetic reset. If the magnetic field changes from rotating CW to CCW and then a magnetic reset is performed, the index value may be decreased. The index value may be adjusted in opposite directions for magnetic resets associated with CW rotation and magnetic resets associated with CCW rotation.

[0091] As the magnetic field rotates CCW after the reset, the turn count of the first magnetic spiral 52 may decrease and the state of the second magnetic spiral 54 may remain the same. The turn count of the multi-turn magnetic sensing system 50 may decrease by one for each full CCW rotation of the magnetic field. During this CCW rotation, the first magnetic spiral 52 is active and the second magnetic spiral 54 is static.

[0092] The magnetic spiral 54 may be magnetically reset after the magnetic field has rotated a full number of CCW turns corresponding to the number of turns of the first magnetic spiral 52. In a multi-turn magnetic sensing system 50, the first magnetic spiral 52 is reset after the magnetic field has rotated 10 full CCW turns from the reset state. The magnetic spirals 52 and 54 may be reset to the reset state.

[0093] After resetting, the first magnetic spiral 52 can continue to adjust its turn count and function as an active sensor when the magnetic field rotates in a CCW direction. The index value can be adjusted after resetting. For example, as shown in Figures 5B-2 and 5B-3, the index value can be decreased in association with a reset and a CCW rotation.

[0094] The multi-turn magnetic sensing system 50 can keep count of the accumulated number of turns of the magnetic field in the CW and CCW directions by magnetically resetting and updating the index value. The turn count can be determined from the state and index value of the magnetic spirals 52 and 54. The multi-turn magnetic sensing system 50 can count to count turns with any suitable number of magnetic field direction changes and any suitable number of magnetic resets.

[0095] As shown in Figures 5B-1-5B-3, the multi-turn magnetic sensing system 50 can have two or more combinations of magnetic tracking 52 and 54 states and index values ​​corresponding to the same turn count. For example, a turn count of 4 corresponds to both (a) a first magnetic spiral 52 having a turn count of 10, a second magnetic spiral 54 having a turn count of 6, and an index value of 1, and (b) a first magnetic spiral 52 having a turn count of 4, a second magnetic spiral 54 having a turn count of 10, and an index value of 1. As another example, a turn count of 23 corresponds to both (a) a first magnetic spiral 52 having a turn count of 10, a second magnetic spiral 54 having a turn count of 7, and an index value of 3, and (b) a first magnetic spiral 52 having a turn count of 6, a second magnetic spiral 54 having a turn count of 7, and an index value of 3.

[0096] In Figures 5B-1-5B-3, turn counts corresponding to full turns from the initialization state are shown. Other valid states are possible for the multi-turn magnetic sensing system 50. Other valid states may include states associated with changes in rotation direction at different turn counts. Other valid states may correspond to turn counts having values ​​outside the ranges of the tables of Figures 5B-1-5B-3.

[0097] The operation of the multi-turn magnetic sensing system 50 is discussed above with reference to a full rotation of the magnetic field. The multi-turn magnetic sensing system 50 can track turns with different resolutions according to any suitable principles and advantages disclosed herein. For example, the decoder can determine the turn count from the output signals associated with the first magnetic spiral 52 and / or the second magnetic spiral 54 with half-turn or quarter-turn resolution. With half-turn resolution, there can be an intermediate state between any two consecutive states associated with a full turn, which can correspond to a half-turn between two consecutive full-turn states. With quarter-turn resolution, there can be three intermediate states between any two consecutive states associated with a full turn, which can correspond to a quarter-turn, a half-turn, and three-quarter-turn.

[0098] Any suitable principles and advantages disclosed with reference to FIG. 5A and / or FIGS. 5B-1 to 5B-3 may be applied to a multi-turn magnetic sensing system, including a magnetic spiral having any suitable number of turns for multi-turn magnetic sensing.

[0099] Although magnetic spirals 52 and 54 have the same number of turns, any of the suitable principles and advantages disclosed with reference to FIG. 5A and / or FIGS. 5B-1 to 5B-3 may be applied to two magnetic spirals having different numbers of turns.

[0100] 6 is a schematic block diagram of a multi-turn magnetic sensing system 60, according to an embodiment. The multi-turn magnetic sensing system 60 can implement indexing and rollover counting, which allows the multi-turn magnetic sensing system 60 to count more rotations of the magnetic field in the CW and CCW directions than the number of turns of the multi-turn sensor 22 or 24.

[0101] In the multi-turn magnetic sensing system 60, the first multi-turn magnetic sensor 22 is a CW sensor and the second multi-turn magnetic sensor 24 is a CCW sensor. The signal conditioning circuit 25 can condition the signals from the first multi-turn sensor 22 and the second multi-turn sensor 24. The multi-turn magnetic sensing system 60 includes a controller 62 that can adjust and store an index value in a memory 64 for rollover counting. The index value can be updated in association with a maximum or minimum turn count reached for one of the multi-turn magnetic sensors 22, 24 due to the rotation of the magnetic field. The controller 62 can control a magnetic reset to magnetically reset the multi-turn magnetic sensors 22 and / or 24 in response to a maximum or minimum turn count reached for one of the multi-turn magnetic sensors 22, 24 due to the rotation of the magnetic field. The multi-turn magnetic sensing system 60 can count infinitely in either the CW or CCW direction.

[0102] The multi-turn magnetic sensing system 60 is similar to the multi-turn magnetic sensing system 20 of Figure 2, except that the multi-turn magnetic sensing system 60 includes a controller 62 having index values ​​stored in a memory 64 and a decoder 65 that uses the index values ​​to decode the turn count. The memory 64 may include any suitable non-transitory memory for storing the index values. The controller 62 may include a counter for updating the index values.

[0103] The decoder 65 can decode the turn count based on the signals from the first and second multi-turn magnetic sensors 22 and 24 and the index value stored in the memory 64. The decoder 65 can output a turn count representative of the accumulated number of turns of the magnetic field. The decoder 65 can determine the turn count according to any suitable principles and advantages discussed with reference to Figures 5A-5B-3. One exemplary mapping of turn count to sensor state and index value is provided in Figures 5B-1-5B-3.

[0104] The controller 65 can control the magnetic reset 27 to magnetically reset the first multi-turn magnetic sensor 22 to a reset state in response to detecting the rotation of the magnetic field causing the first multi-turn magnetic sensor 22 to reach an end value, such as a maximum or minimum turn count of the first multi-turn magnetic sensor 22. In certain cases, the magnetic reset 27 can magnetically reset the second multi-turn magnetic sensor 24 while magnetically resetting the first multi-turn magnetic sensor 22. The controller 65 can control the magnetic reset 27 to magnetically reset the second multi-turn magnetic sensor 24 to a reset state in response to detecting the rotation of the magnetic field causing the second multi-turn magnetic sensor 24 to reach an end value, such as a maximum or minimum turn count of the second multi-turn magnetic sensor 24. In certain cases, the magnetic reset 27 can magnetically reset the first multi-turn magnetic sensor 22 while magnetically resetting the second multi-turn magnetic sensor 24.

[0105] Figure 7 is a schematic block diagram of a multi-turn magnetic sensing system 70 including an angle sensor 32, according to an embodiment. The multi-turn magnetic sensing system 70 is similar to the multi-turn magnetic sensing system 60 of Figure 6, except that the multi-turn magnetic sensing system 70 also includes an angle sensor 32, and a processing circuit of the multi-turn magnetic sensing system 70 can combine the angle and turn count to generate a position measurement. The angle sensor 32 can be implemented according to any suitable principles and advantages discussed with reference to Figure 3.

[0106] The quadrant detector may be implemented with a multi-turn magnetic sensing system with rollover counting according to any suitable principles and advantages discussed with reference to FIGS. 6 and / or 7.

[0107] Although certain embodiments are disclosed having rollover counting in both CW and CCW directions, any suitable principles and advantages of rollover counting and indexing disclosed herein may be applied to a multi-turn magnetic sensing system arranged to unidirectionally count turns from an initialized state. Such a magnetic sensing system can count cumulative turns of a magnetic field in either a CW or CCW direction.

[0108] FIG. 8 is a schematic block diagram of an embodiment of a multi-turn magnetic sensing system 80 and a single multi-turn magnetic sensor 82 with rollover counting. The multi-turn magnetic sensing system 80 is similar to the multi-turn magnetic sensing system 60 of FIG. 6, except that the multi-turn magnetic sensing system 80 includes a single multi-turn magnetic sensor 82. The multi-turn magnetic sensing system 80 can cumulatively count turns of the magnetic field from an initialization state in either a CW or CCW direction, depending on whether the multi-turn magnetic sensor 82 is a CCW sensor such as the second multi-turn magnetic sensor 24 or a CW sensor such as the first multi-turn magnetic sensor 22, and the initialization state. The controller 62 can update an index value stored in the memory 64, and the decoder 65 can decode the turn count according to any suitable principles and advantages discussed with reference to FIGS. 5A-7 as applied to counting cumulative turns of the magnetic field in either a CW or CCW direction.

[0109] In some other applications, a single multi-turn magnetic sensor may be used for rollover counting in both the CW and CCW directions. In response to the single multi-turn magnetic sensor reaching a domain wall-empty state due to the rotation of the magnetic field in a first direction, the single multi-turn magnetic sensor may be magnetically reset to be domain wall-filled and the index value may be updated accordingly. In response to the single multi-turn magnetic sensor reaching a domain wall-filled state due to the rotation of the magnetic field in a second direction opposite the first direction, the single multi-turn magnetic sensor may be reset to be domain wall-empty and the index value may be updated accordingly.

[0110] Uses, Terminology, and Conclusions The multi-turn magnetic sensing systems disclosed herein may be implemented in any suitable application that can benefit from counting turns of a rotating magnetic field. Exemplary applications include, but are not limited to, electronic power steering (EPS) applications such as EPS steer-by-wire actuator applications, parking lock actuators, seat belt retractors, transmission actuators, other vehicle applications, robotic and / or cobot applications such as arm joint position tracking, rotary to linear actuator applications, wire drawing encoder applications, other industrial automation applications, etc.

[0111] In the embodiments described above, sensors, circuits, systems, and methods for multi-turn magnetic sensing are described with reference to specific embodiments, however, it should be understood that the principles and advantages of the embodiments may be used with any other suitable sensors, circuits, systems, and methods having multi-turn magnetic sensing.

[0112] Unless the context clearly requires otherwise, throughout the specification and claims, words such as "comprise," "comprising," "include," "including," and the like, should be interpreted in an inclusive sense, i.e., "including, but not limited to," as opposed to an exclusive or exhaustive sense. The words "coupled" or "connected," as generally used herein, refer to two or more elements that may be directly connected or connected by one or more intermediate elements. Thus, the various schematic diagrams shown in the figures depict example configurations of elements and components, but additional intervening elements, devices, features, or components may be present in an actual embodiment (assuming the functionality of the depicted circuit is not adversely affected). Additionally, the words "herein," "above," "below," and words of similar import, when used herein, shall refer to the entire specification and not any particular portion of the specification. Where the context permits, words in the detailed description using singular or plural numerical values ​​may also include the plural or singular numerical values, respectively. The word "or" referring to a list of two or more items is intended to cover the following interpretations of the word: any item in the list, every item in the list, and any combination of items in the list. All numerical values ​​provided herein are intended to include similar values ​​within the error of measurement.

[0113] Additionally, conditional language used herein, such as, among others, "can," "could," "might," "may," "eg," "for example," "such as," and the like, is generally intended to convey that certain embodiments include particular features, elements, and / or steps while other embodiments do not, unless specifically stated otherwise or understood within the context when used otherwise.

[0114] The teachings of the embodiments provided herein may be applied to other systems, not necessarily those described above. Elements and acts of the various embodiments described above may be combined to provide further embodiments. The acts of the methods discussed herein may be performed in any order, as appropriate. Moreover, the acts of the methods discussed herein may be performed sequentially or in parallel, as appropriate.

[0115] Although certain embodiments of the present invention have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the present disclosure. Indeed, the novel circuits, methods, and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and changes in the form of the circuits, methods, devices, and systems described herein may be made without departing from the spirit of the present disclosure. For example, while the disclosed embodiments are presented in a given configuration, alternative embodiments may implement similar functionality with different components and / or circuit topologies, and some elements may be deleted, moved, added, subdivided, combined, and / or modified. Each of these elements may be implemented in a variety of different ways. Any suitable combination of elements and functions of the various embodiments described above may be combined to provide further embodiments. The appended claims and their equivalents are intended to cover such forms or modifications as are within the scope and spirit of the present disclosure. Accordingly, the scope of the present invention is defined by reference to the claims.

[0116] The claims presented herein are in single dependent form for purposes of filing with the USPTO, but it is understood that any claim may depend on any prior claim of the same type unless clearly technically not feasible. [Explanation of symbols]

[0117] 10 Multi-turn magnetic sensing system 12 First Magnetic Spiral 14 The Second Magnetic Spiral 15 Magnetoresistance element 16 Domain wall generator 20 Multi-turn magnetic sensing system 21 Magnetic Target 22 First multi-turn magnetic sensor 24 Second Multi-Turn Magnetic Sensor 25 Signal conditioning circuit 26 Controller 27 Magnetic Reset 28 Readout circuit 29 Decoder 30 Multi-turn magnetic sensing system 32 Angle Sensor 40 Multi-turn magnetic sensing system 42 Quadrant Detector 50 Multi-turn magnetic sensing system 52 First Magnetic Spiral 54 Second Magnetic Spiral 60 Multi-turn magnetic sensing system 62 Controller 64 Memory 65 Decoder 70 Multi-turn magnetic sensing system 80 Multi-turn magnetic sensing system 82 Multi-turn magnetic sensor

Claims

1. 1. A multi-turn magnetic sensing system comprising: a first multi-turn magnetic sensor; a second multi-turn magnetic sensor, wherein a domain wall propagates in an opposite direction in the second multi-turn magnetic sensor relative to the first multi-turn magnetic sensor in response to a magnetic field; a decoder configured to output a turn count based on output signals from the first multi-turn magnetic sensor and the second multi-turn magnetic sensor.

2. 2. The multi-turn magnetic sensing system of claim 1, wherein the decoder is configured to determine the turn count within a range from a first value to a second value for a state of the first multi-turn magnetic sensor and the second multi-turn magnetic sensor for a reset state, and the turn count for the reset state is between the first value and the second value.

3. 3. The multi-turn magnetic sensing system of claim 2, wherein the first multi-turn magnetic sensor and the second multi-turn magnetic sensor are each configured to count an equal number of turns in opposite directions, and the turn count for the reset state is a midpoint between the first value and the second value.

4. The multi-turn magnetic sensing system of claim 2 , wherein the first multi-turn magnetic sensor and the second multi-turn magnetic sensor are each filled with domain walls in the reset state.

5. 2. The multi-turn magnetic sensing system of claim 1, wherein the decoder is configured to determine the turn count for two or more full clockwise rotations of the magnetic field from a reset state, and to determine the turn count for two or more full counterclockwise rotations of the magnetic field from the reset state.

6. 2. The multi-turn magnetic sensing system of claim 1, further comprising a magnetic reset configured to magnetically reset the first multi-turn magnetic sensor and the second multi-turn magnetic sensor to a reset state, wherein the decoder is configured to determine the turn count for the reset state within a range from a first value to a second value, the turn count for the reset state having a value between the first value and the second value.

7. 7. The multi-turn magnetic sensing system of claim 6, wherein the magnetic reset comprises a coil configured to apply a reset magnetic field to reset the first multi-turn magnetic sensor and the second multi-turn magnetic sensor to the reset state.

8. 7. The multi-turn magnetic sensing system of claim 6, further comprising: a memory configured to store an index value, wherein the multi-turn magnetic sensing system is configured to update the index value in association with magnetically resetting the first multi-turn magnetic sensor and the second multi-turn magnetic sensor, and wherein the decoder is configured to generate the turn count based on the index value and the output signals from the first multi-turn magnetic sensor and the second multi-turn magnetic sensor.

9. The multi-turn magnetic sensing system of claim 1 , wherein the multi-turn magnetic sensing system operates in a subset of valid states of the first multi-turn magnetic sensor and the second multi-turn magnetic sensor when operating in a balanced state.

10. 2. The multi-turn magnetic sensing system of claim 1, wherein the first multi-turn magnetic sensor and the second multi-turn magnetic sensor have states corresponding to the same number of turns as a reset state, and the first multi-turn magnetic sensor and the second multi-turn magnetic sensor are not configured to move from the states to the reset state with a rotation of the magnetic field.

11. The multi-turn magnetic sensing system of claim 1 , wherein the turn count has the same value for at least two different states of the first multi-turn magnetic sensor and the second multi-turn magnetic sensor.

12. 2. The multi-turn magnetic sensing system of claim 1, further comprising an angle sensor and processing circuitry configured to output a position measurement, the position measurement being based on the turn count and an angle, the angle being based on an output signal of the angle sensor.

13. 1. A multi-turn magnetic sensing system having a mid-range reset, comprising: a first multi-turn magnetic sensor; a second multi-turn magnetic sensor, wherein domain walls propagate in opposite directions in the second multi-turn magnetic sensor and the first multi-turn magnetic sensor in response to a magnetic field; a decoder configured to output a turn count associated with a state of the first multi-turn magnetic sensor and the second multi-turn magnetic sensor, the turn count being within a range from a minimum value to a maximum value for a reset state, the turn count for the reset state being between the minimum value and the maximum value.

14. The multi-turn magnetic sensing system of claim 13 , further comprising a magnetic reset configured to magnetically reset the first multi-turn magnetic sensor and the second multi-turn magnetic sensor to the reset state.

15. 1. A method of multi-turn magnetic sensing with mid-range reset, comprising: resetting a first multi-turn sensor and a second multi-turn sensor to a reset state, where domain walls propagate in opposite directions in the first multi-turn sensor and the second multi-turn sensor in response to a rotation of a magnetic field; detecting a first non-zero number of turns of the magnetic field from the reset state based on reading first values ​​from the first multi-turn sensor and the second multi-turn sensor, the first non-zero number of turns representing a cumulative rotation of the magnetic field in a clockwise direction from the reset state; detecting a second non-zero number of turns of the magnetic field relative to the reset state based on reading second values ​​from the first multi-turn sensor and the second multi-turn sensor, the second non-zero number of turns representing that the accumulated rotation of the magnetic field is in a counterclockwise direction from the reset state.

16. The method of claim 15 further comprising generating a position measurement based on the turn count and the angle information.

17. The method of claim 15 , wherein the first multi-turn sensor and the second multi-turn sensor each comprise a magnetic spiral having the same number of turns.

18. The method of claim 15 , wherein the first multi-turn sensor and the second multi-turn sensor are each filled with a domain wall in the reset state.

19. magnetically resetting the first multi-turn sensor in response to the magnetic field rotating a particular number of turns; updating an index value stored in a memory in association with said magnetically resetting; 16. The method of claim 15, further comprising: determining a turn count based on the index value after the updating and an additional rotation of the magnetic field, and reading a third value from the first multi-turn sensor and the second multi-turn sensor.

20. The method of claim 15 , further comprising generating a position measurement based on turn count and angle information associated with the magnetic field.

21. 1. A method of multi-turn magnetic sensing with rollover counting, comprising: resetting a multi-turn magnetic sensor to a reset state, the multi-turn magnetic sensor comprising a magnetic spiral having N turns, where N is a positive integer greater than 1; updating an index value in association with said resetting; determining a turn count based on an output signal from the multi-turn magnetic sensor and the index value, the turn count having a value having a magnitude greater than N.

22. The method of claim 21 , wherein the resetting comprises applying a reset magnetic field to the multi-turn magnetic sensor using a coil.

23. The method of claim 21 , wherein the resetting comprises moving a permanent magnet into proximity with the multi-turn magnetic sensor.

24. 22. The method of claim 21, wherein the determining is also based on an output signal from a second multi-turn magnetic sensor, and wherein domain walls propagate in an opposite direction in the second multi-turn magnetic sensor compared to the multi-turn magnetic sensor.

25. generating a turn count having a second value after an additional rotation of the magnetic field subsequent to said determining; the value represents a clockwise rotation from an initialization state; 25. The method of claim 24, wherein the second value represents a counterclockwise rotation from the initialized state.

26. 25. The method of claim 24, wherein the multi-turn magnetic sensor and the second multi-turn magnetic sensor are each filled with domain walls in the reset state.

27. 22. The method of claim 21, wherein the turn count has a quarter turn resolution.

28. processing an output signal from the angle sensor to generate angle information; The method of claim 21 , further comprising: generating a position measurement based on the turn count and the angle information.

29. 1. A multi-turn magnetic sensing system with rollover counting, comprising: a multi-turn magnetic sensor comprising a magnetic spiral having N turns, N being a positive integer greater than 1; processing circuitry; The processing circuitry comprises: a memory configured to store the index value; a decoder configured to determine a turn count having a value having a magnitude greater than N based on an output signal from the multi-turn magnetic sensor and the index value, the turn count representing a number of rotations of a magnetic field.

30. 30. The multi-turn magnetic sensing system of claim 29, further comprising a magnetic reset configured to magnetically reset the magnetic spiral.

31. 31. The multi-turn magnetic sensing system of claim 30, wherein the magnetic reset comprises a coil configured to apply a reset magnetic field to magnetically reset the magnetic spiral in response to a control signal from the processing circuit.

32. 31. The multi-turn magnetic sensing system of claim 30, wherein the processing circuitry is configured to update the index value in association with magnetically resetting the magnetic spiral.

33. 31. The multi-turn magnetic sensing system of claim 30, wherein the processing circuitry is configured to update the index value in response to detecting a rotation of the magnetic field after magnetically resetting the magnetic spiral.

34. 30. The multi-turn magnetic sensing system of claim 29, further comprising a second multi-turn magnetic sensor, the second multi-turn magnetic sensor comprising a second magnetic spiral, domain walls propagating in opposite directions in the magnetic spiral and the second magnetic spiral, and the decoder configured to determine the turn count based on the output signal from the multi-turn magnetic sensor, the output signal from the second multi-turn magnetic sensor, and the index value.

35. The multi-turn magnetic sensing system of claim 34 , wherein the second magnetic spiral has N turns.

36. The multi-turn magnetic sensing system of claim 34 , wherein the processing circuitry is configured to detect changes in a rotational direction of the magnetic field.

37. 35. The multi-turn magnetic sensing system of claim 34, wherein the decoder is configured to determine the turn count at a second value having a magnitude greater than N, the value representing a clockwise rotation from an initialization state, and the second value representing a counterclockwise rotation from the initialization state.

38. 30. The multi-turn magnetic sensing system of claim 29, further comprising an angle sensor, wherein the processing circuitry is configured to output a position measurement based on the turn count and angle information from the angle sensor.

39. 1. A multi-turn magnetic sensing system with rollover counting, comprising: a first multi-turn magnetic sensor comprising a first magnetic spiral having N turns, where N is a positive integer greater than 1; a second multi-turn magnetic sensor, wherein domain walls propagate in opposite directions in the second multi-turn magnetic sensor and the first multi-turn magnetic sensor in response to a magnetic field; a decoder configured to output a turn count based on an index value and a state of the first multi-turn magnetic sensor and the second multi-turn magnetic sensor, the decoder being configured to determine the turn count for more than N complete clockwise rotations of the magnetic field from an initialization state, and to determine the turn count for more than N complete counterclockwise rotations of the magnetic field from the initialization state.

40. a magnetic reset configured to magnetically reset the first multi-turn magnetic sensor to a reset state; 40. The multi-turn magnetic sensing system of claim 39, further comprising: a processing circuit configured to update the index value in association with magnetically resetting the first multi-turn magnetic sensor.

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