Single-Channel Magnetoresistance Angle Sensing With Tangent Processing
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Solution Overview
Problem
Traditional magnetic-field angle sensors require two channels to determine the tangent value of a magnetic field angle, leading to increased integrated circuit area and power consumption.
Innovation Solution
An analog circuitry generates an analog value proportional to the tangent value of the magnetic field angle using magnetoresistance elements, which is then converted to a digital value and processed using a CORDIC algorithm to calculate the angle, reducing the need for a two-channel solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a two-channel solution is used to determine the tangent value of the magnetic field angle, then measurement precision is improved, but integrated circuit area increases
Solution Approach 1:
The patent combines the sine and cosine signal processing into a single channel by using an analog circuit that directly computes the tangent value from the magnetoresistance element outputs. Instead of maintaining separate processing paths for sine and cosine signals, the invention merges these operations into one integrated path that produces the tangent value in a single channel, thereby reducing the integrated circuit area while preserving measurement precision.
2Measurement precision
If a two-channel solution is used to determine the tangent value of the magnetic field angle, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent reduces power consumption by merging the two-channel processing architecture into a single-channel architecture. The analog circuit directly computes the tangent value from the magnetoresistance element outputs without requiring separate processing channels for sine and cosine signals. This consolidation reduces the number of active circuit components and their associated power consumption while maintaining the precision needed for accurate angle determination.
3Device complexity
If analog circuitry is used to generate tangent value directly, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs parameter changes by using the ratio of resistance changes in the magnetoresistance elements to compute the tangent value. This approach transforms the problem from requiring precise physical alignment of multiple channels to requiring accurate measurement of resistance parameters. The analog circuit processes these resistance parameters to generate the tangent value, reducing device complexity while managing manufacturing precision requirements through parameter-based computation rather than geometry-based computation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces integrated circuit area and power consumption while accurately determining the angle of a magnetic-field vector, enhancing efficiency and performance.
Implementation Method 1
The analog circuitry includes a plurality of magnetoresistance elements that include a first magnetoresistance element configured to provide a cosine value indicative of the 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
Data Source
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AI summary
An angle sensor (12) is provided which includes analog circuitry (14) configured to generate an analog value having a tangent value, an analog-to-digital converter (18) configured to convert the analog value to a digital value and digital circuitry (20) 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 (146) configured to use the digital value and a fixed value (148) in an arctangent algorithm to generate an angle of a direction of the magnetic field.