# US 10,481,220 B2 · Circular vertical hall (CVH) sensing element with signal processing and arctangent function > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,481,220 B2 - Document ID: US10481220B2 - Status: Granted - Kind: B2 - Application number: 15/012,142 - Filed: 2016-02-01 - Published: 2017-08-03 - Granted: 2019-11-19 - Earliest claimed: 2016-02-01 - Assignees: Allegro MicroSystems, LLC - Applicants: Allegro Microsystems, LLC - Inventors: Octavio H. Alpago; Ezequiel Alves; Hernán D. Romero - Web page: https://patentgrep.com/patent/US10481220B2 ## CPC - G01R 33/077: {Vertical Hall-effect devices} - G01D 5/145: {influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06)} - G01D 5/2448: {Correction of gain, threshold, offset or phase control} - G01R 33/0029: {Treating the measured signals, e.g. removing offset or noise} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - 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 ## Abstract A magnetic field sensor includes a circular vertical Hall (CVH) sensing element to produce a signal representing an external magnetic field as detected by the CVH sensing element, a sigma-delta analog-to-digital converter to generate a converted signal, modulators to produce quadrature modulated signals from the converted signal, and a processor to produce an estimated angle of the external magnetic field using the quadrature modulated signals. An arctangent function may be used to calculate the estimated angle. A sliding window integration scheme may be used over one or more CVH cycles. ## Claims ### Claim 1 A magnetic field sensor, comprising: a circular vertical Hall (CVH) sensing element to produce an analog signal representing an external magnetic field; an analog-to-digital converter coupled to receive the analog signal and produce a digital signal; a quadrature modulator circuit coupled to the digital signal and operable to generate a plurality of quadrature modulated signals comprising a first modulated signal and a second modulated signal, wherein the quadrature modulator circuit comprises: a first modulator to modulate the digital signal by applying a cosine signal to the digital signal to generate the first modulated signal, wherein the cosine signal is associated with a frequency associated with a duty cycle of the CVH sensing element; a second modulator to modulate the signal by applying a sine signal to the digital signal to generate the second modulated signal, wherein the sine signal is associated with the frequency associated with the duty cycle of the CVH sensing element; and a processor stage coupled to use signals representative of the plurality of quadrature modulated signals and operable to perform an arctangent calculation to determine an estimated angle of the external magnetic field, wherein the processor stage comprises a circuit to perform a Coordinate Rotation Digital Computer (CORDIC) algorithm to perform the arctangent calculation on the first modulated signal and the second modulated signal to determine the estimated angle of the external magnetic field. ### Claim 2 (depends on 1) The magnetic field sensor of claim 1 wherein the circuit to perform the CORDIC algorithm is a processor configured to execute instructions that cause the processor to perform the CORDIC algorithm. ### Claim 3 (depends on 2) The magnetic field sensor of claim 2 wherein the instructions are software instructions, firmware instructions, micro-code instructions, or a combination thereof. ### Claim 4 (depends on 1) The magnetic field sensor of claim 1 wherein the arctangent calculation produces an estimated angle has an accuracy greater than a predetermined angle between one or more vertical Hall element contacts of the CVH sensing element. ### Claim 5 (depends on 1) The magnetic field sensor of claim 1 wherein the analog-to-digital converter is a sigma-delta analog-to-digital converter and the digital signal is a pulse stream. ### Claim 6 (depends on 5) The magnetic field sensor of claim 5 wherein the sigma-delta analog-to-digital converter comprises a noise shaping transform that shifts quantization noise to higher frequencies. ### Claim 7 (depends on 1) The magnetic field sensor of claim 1 wherein the processor stage is further configured to perform a sliding window integration using the signals representative of the plurality of quadrature modulated signals. ### Claim 8 (depends on 1) The magnetic field sensor of claim 1 wherein the processor stage is configured to perform the arctangent calculation to compute the estimated angle at a frequency greater than that of a CVH cycle. ### Claim 9 (depends on 1) The magnetic field sensor of claim 1 wherein the processor stage is configured to calculate a quotient of the first modulated signal divided by the second modulated signal. ### Claim 10 (depends on 9) The magnetic field sensor of claim 9 wherein the processor stage is configured to perform the arctangent calculation using the quotient. ### Claim 11 (depends on 1) The magnetic field sensor of claim 1, further comprising at least one filter coupled to the quadrature modulator circuit and to the processor circuit, the at least one filters filtering the first and second modulated signals from the quadrature modulator circuit prior to being provided to the processor circuit. ### Claim 12 (depends on 1) The magnetic field sensor of claim 1, wherein the least one filter is at least one integrator, the at least one integrator integrates the first and second modulated signals from zero to a period of a CVH cycle. ### Claim 13 A method comprising: detecting a magnetic field by a circular vertical Hall (CVH) sensing element; producing, by the CVH sensing element, an analog signal representing the external magnetic field; converting the analog signal to a digital signal; generating a plurality of quadrature modulated signals comprising a first modulated signal and a second modulates signal, the generating comprising: applying a cosine signal to the digital signal to generate the first modulated signal, wherein the cosine signal is associated with a frequency associated with a duty cycle of the CVH sensing element; and applying a sine signal to the digital signal to generate the second modulated signal, wherein the sine signal is associated with the frequency associated with the duty cycle of the CVH sensing element; and performing an arctangent calculation to determine an estimated angle of the external magnetic field, the performing comprising using a Coordinate Rotation Digital Computer (CORDIC) algorithm to perform the arctangent calculation on the first modulated signal and the second modulated signal to determine the estimated angle of the external magnetic field. ### Claim 14 (depends on 13) The method of claim 13 wherein the CORDIC algorithm is performed by a processor configured to execute instructions that cause the processor to perform the CORDIC algorithm. ### Claim 15 (depends on 14) The method of claim 14 wherein the instructions are software instructions, firmware instructions, micro-code instructions, or a combination thereof. ### Claim 16 (depends on 13) The method of claim 13 wherein the performing the arctangent calculation comprises producing an estimated angle that has an accuracy greater than a predetermined angle between one or more vertical Hall element contacts of the CVH sensing element. ### Claim 17 (depends on 13) The method of claim 13 wherein converting the analog signal comprises generating a sigma-delta encoded bit stream representing the analog signal. ### Claim 18 (depends on 17) The method of claim 17 wherein converting the analog signal comprises applying a noise shaping transform to the analog signal that shifts quantization noise to higher frequencies. ### Claim 19 (depends on 13) The method of claim 13 further comprising performing a sliding window integration using the plurality of quadrature modulated signals. ### Claim 20 (depends on 19) The method of claim 19 further comprising performing the arctangent calculation to compute the estimated angle at a frequency greater than that of a CVH cycle. ### Claim 21 (depends on 13) The method of claim 13 further comprising calculating a quotient of the first modulated signal divided by the second modulated signal. ### Claim 22 (depends on 21) The magnetic field sensor of claim 21 wherein performing the arctangent calculation comprises performing the arctangent calculation using the quotient. ### Claim 23 (depends on 13) The magnetic field sensor of claim 13, further comprising filtering the first and second modulated signals from the quadrature modulator circuit prior to being provided to the processor circuit. ### Claim 24 (depends on 23) The magnetic field sensor of claim 23, wherein the filtering comprises integrating the first and second modulated signals from zero to a period of a CVH cycle.