# US 11,307,017 B2 · Single channel magnetoresistance-based angle sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,307,017 B2 - Document ID: US11307017B2 - Status: Granted - Kind: B2 - Application number: 16/749,074 - Filed: 2020-01-22 - Published: 2021-07-22 - Granted: 2022-04-19 - Earliest claimed: 2020-01-22 - Assignees: Allegro MicroSystems, LLC - Applicants: Allegro MicroSystems, LLC - Inventors: Hernán D. Romero - Web page: https://patentgrep.com/patent/US11307017B2 ## CPC - G01B 7/30: for measuring angles or tapers; for testing the alignment of axes - G01D 5/145: {influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06)} - G01D 3/0365: {the undesired influence being measured using a separate sensor, which produces an influence related signal} - G01D 5/24485: {using other sensors} - H03F 3/45: Differential amplifiers (differential sense amplifiers G11C7/062) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - H03F: AMPLIFIERS ## Abstract In one aspect, an angle sensor includes analog circuitry configured to generate an analog value having a tangent value, an analog-to-digital converter configured to convert the analog value to a digital value and digital circuitry configured to receive the digital value. The analog circuitry includes a plurality of magnetoresistance elements that include a first magnetoresistance element configured to provide a cosine value indicative of a magnetic field along a first axis and a second magnetoresistance element configured to provide a sine value indicative of the magnetic field along a second axis orthogonal to the first axis. The tangent value is determined by the cosine and sine values. The digital circuitry includes an angle processor configured to use the digital value and a fixed value in an arctangent algorithm to generate an angle of a direction of the magnetic field. ## Claims ### Claim 1 An angle sensor comprising: analog circuitry configured to generate an analog value having a tangent value, the analog circuitry comprising a plurality of magnetoresistance elements comprising: a first magnetoresistance element configured to provide a cosine value indictive of a magnetic field along a first axis; and a second magnetoresistance element configured to provide a sine value indicative of the magnetic field along a second axis orthogonal to the first axis, wherein the tangent value is determined by the cosine value and the sine value; an analog-to-digital converter (ADC) configured to convert the analog value to a digital value; and digital circuitry configured to receive the digital value, the digital circuitry comprising an angle processor configured to use the digital value and a fixed value in an arctangent algorithm to generate an angle of a direction of the magnetic field, wherein the analog circuitry comprises: a variable gain amplifier configured to receive a first current inversely proportional to the cosine value; a transistor having a drain configured to provide the first current and a gate connected to an output of an amplifier; and the variable gain amplifier having a first input configured to receive a reference voltage. ### Claim 2 (depends on 1) The angle sensor of claim 1, wherein the variable gain amplifier having a second input connected to the first magnetoresistance element, and wherein the transistor having a source connected to the first magnetoresistance element. ### Claim 3 (depends on 1) The angle sensor of claim 1, wherein the variable gain amplifier having a second input connected to a source of the transistor, and wherein in a first mode the source of the transistor is connected to the first magnetoresistance element and in a second mode, the source of the source of the transistor is connected to a fixed current. ### Claim 4 (depends on 1) The angle sensor of claim 1, wherein in the first mode the fixed value is 1 and in the second mode the fixed value is zero. ### Claim 5 (depends on 1) The angle sensor of claim 1, wherein the variable gain amplifier is further configured to receive a second current inversely proportional to the sine value. ### Claim 6 (depends on 1) The angle sensor of claim 1, wherein the transistor is a first transistor, the amplifier is a first amplifier and the reference voltage is a first reference voltage, wherein the analog circuitry further comprises: a second transistor having a drain configured to provide the second current, a source connected to the second magnetoresistance element and a gate connected to an output of a second amplifier; and the amplifier having a first input configured to receive a second reference voltage. ### Claim 7 (depends on 1) The angle sensor of claim 1, wherein the amplifier is further configured to receive a second current from a fixed current source. ### Claim 8 (depends on 7) The angle sensor of claim 7, wherein the analog circuitry further comprises a bridge comprising the second magnetoresistance element, wherein a differential output of the bridge is proportional to a sine indicative of the magnetic field along the second axis, wherein the bridge provides an input voltage to the variable gain amplifier. ### Claim 9 (depends on 1) The angle sensor of claim 1, wherein the analog circuitry further comprises: a Gilbert cell configured to receive a first current inversely proportional to the cosine value and to receive a second current from a fixed current source; a transistor having a drain configured to provide the first current and a gate connected to an output of a first amplifier; and the first amplifier having a first input connected to a source of the transistor and to a first resistor connected to a ground and having a second input connected to: an output of a second amplifier; a second resistor connected to a third resistor; and a half-bridge whose two magnetoresistance elements are proportional to +cos and −cos of the magnetic field angle. ### Claim 10 (depends on 9) The angle sensor of claim 9, wherein a first input of the second amplifier is connected to the half-bridge whose two magnetoresistance MR elements are proportional to +cos and −cos of the magnetic field angle and to the first magnetoresistance (proportional to cos of the magnetic field angle element and a second input of the second amplifier connected to the second resistor and a third resistor, the third resistor being connected to ground. ### Claim 11 (depends on 1) The angle sensor of claim 1, wherein in the fixed value is 1. ### Claim 12 (depends on 1) The angle sensor of claim 1, wherein the first magnetoresistance element is a giant magnetoresistance element or a tunnel magnetoresistance element. ### Claim 13 (depends on 12) The angle sensor of claim 12, wherein the second magnetoresistance element is a giant magnetoresistance element or a tunnel magnetoresistance element. ### Claim 14 (depends on 1) The angle sensor of claim 1, wherein the angle processor is a CORDIC (Coordinate Rotation Digital Computer). ### Claim 15 An angle sensor comprising: analog circuitry configured to generate an analog value having a tangent value, the analog circuitry comprising a plurality of magnetoresistance elements comprising: a first magnetoresistance element configured to provide a cosine value indictive of a magnetic field along a first axis; and a second magnetoresistance element configured to provide a sine value indicative of the magnetic field along a second axis orthogonal to the first axis, wherein the tangent value is determined by the cosine value and the sine value; an analog-to-digital converter (ADC) configured to convert the analog value to a digital value; and digital circuitry configured to receive the digital value, the digital circuitry comprising an angle processor configured to use the digital value and a fixed value in an arctangent algorithm to generate an angle of a direction of the magnetic field; and a third magnetoresistance element configured to provide the sine value indicative of the magnetic field along the second axis, wherein the analog circuitry comprises an amplifier having a first input connected to the first magnetoresistance element and the second magnetoresistance element, a second input connected to the first magnetoresistance element and the second magnetoresistance element and a first output connected to the second magnetoresistance element and the ADC and a second output connected to the third magnetoresistance element and the ADC. ### Claim 16 (depends on 15) The angle sensor of claim 15, wherein the first magnetoresistance element and/or the second magnetoresistance element is a giant magnetoresistance element or a tunnel magnetoresistance element. ### Claim 17 (depends on 16) The angle sensor of claim 16, wherein the third magnetoresistance element is a giant magnetoresistance element or a tunnel magnetoresistance element. ### Claim 18 An angle sensor comprising: analog circuitry configured to generate an analog value having a tangent value, the analog circuitry comprising a plurality of magnetoresistance elements comprising: a first magnetoresistance element configured to provide a cosine value indictive of a magnetic field along a first axis; and a second magnetoresistance element configured to provide a sine value indicative of the magnetic field along a second axis orthogonal to the first axis, wherein the tangent value is determined by the cosine value and the sine value; an analog-to-digital converter (ADC) configured to convert the analog value to a digital value; and digital circuitry configured to receive the digital value, the digital circuitry comprising an angle processor configured to use the digital value and a fixed value in an arctangent algorithm to generate an angle of a direction of the magnetic field; a bridge comprising the second magnetoresistance element; a third magnetoresistance element configured to provide the cosine value indicative of the magnetic field along the first axis; and a fourth magnetoresistance element configured to provide the cosine value indicative of the magnetic field along the first axis; wherein the analog circuitry comprises: a buffer connected to an output of the bridge; a first amplifier having a first input, a second input connected to the first magnetoresistance element and an output connected to the third magnetoresistance element and the ADC; a first resistor connected to the buffer and the first input of the first amplifier; a second resistor connected to the first input of the amplifier and the output of the first amplifier; a second amplifier having a first input, a second input connected to the first magnetoresistance element and an output connected to the fourth magnetoresistance element and the ADC; a third resistor connected to the buffer and the first input of the second amplifier; and a fourth resistor connected to the first input of the second amplifier and the output of the second amplifier. ### Claim 19 (depends on 18) The angle sensor of claim 18, wherein the first magnetoresistance element and/or the second magnetoresistance element is a giant magnetoresistance element or a tunnel magnetoresistance element. ### Claim 20 (depends on 19) The angle sensor of claim 19, wherein the third magnetoresistance element and/or the fourth magnetoresistance element is a giant magnetoresistance element or a tunnel magnetoresistance element.