Hybrid AMR and Hall Sensor Assembly for 360-Degree Angle Measurement
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Solution Overview
Problem
Magnetic sensors, particularly in automotive applications, face challenges in accurately measuring the direction of a magnetic field over a full 360° range without the complexity and cost of GMR sensors, and existing solutions like Hall sensors suffer from ambiguities near 0° and 180° angles.
Innovation Solution
A magnetic field sensor assembly combining AMR sensors and Hall effect sensors, with processing circuitry to determine the uncorrected magnetic field angle and apply offset angles based on logical combinations of output signals from both types of sensors, allowing for unambiguous 360° measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GMR sensors are used to achieve high sensitivity and 360° measurement capability, then measurement precision is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent combines AMR sensors and Hall effect sensors in a hybrid configuration where AMR sensors provide high sensitivity for angle measurement and Hall sensors provide polarity information. This merging of two simpler sensor types achieves the 360° measurement capability without requiring complex GMR sensor structures, thus improving measurement precision while controlling device complexity
Solution Approach 2:
The sensor system is designed to perform multiple functions: AMR sensors measure angle magnitude with high sensitivity while Hall sensors determine field polarity. The processing circuitry integrates both sensor types to provide complete directional information (0-360°), making the system universally capable of full-range angle measurement without requiring expensive GMR technology
2Measurement precision
If AMR sensors are used to achieve high sensitivity, then measurement precision is improved, but device complexity increases due to separate fabrication requirements
Solution Approach 1:
The patent merges AMR sensors with Hall effect sensors in a unified package where the Hall sensor is positioned adjacent to the AMR sensor bridge. This combination allows the system to leverage the high sensitivity of AMR sensors while using the simpler Hall sensor to resolve polarity ambiguities, achieving complete 360° measurement without the full complexity of GMR sensors
Solution Approach 2:
The Hall sensor acts as an intermediary element that provides polarity information to the AMR sensor system. By detecting the direction of the magnetic field (positive or negative polarity), the Hall sensor enables the AMR sensor to distinguish between 0-180° and 180-360° ranges, effectively extending the measurement capability without requiring the AMR sensor itself to be overly complex
3Device complexity
If single-sensor systems are used to reduce device complexity, then device complexity is reduced, but measurement precision deteriorates due to ambiguities near 0° and 180° angles
Solution Approach 1:
The patent combines AMR sensors with Hall effect sensors to resolve measurement ambiguities. The AMR sensor provides sensitive angle measurement while the Hall sensor provides polarity information that eliminates ambiguities near 0° and 180°. This merging of sensor types achieves complete 360° unambiguous measurement without requiring excessive complexity in a single sensor design
Solution Approach 2:
The processing circuitry uses feedback from both the AMR sensor and Hall sensor to continuously determine the correct angle range. The Hall sensor's polarity detection provides feedback that guides the AMR sensor reading into the correct 180° quadrant, eliminating ambiguities and ensuring precise measurement across the full 360° range
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 combination provides a cost-effective and robust solution for accurately determining the direction of a magnetic field over a full 360° range, avoiding ambiguities and the limitations of single-sensor systems, enabling immediate and accurate operation in safety-critical applications.
Implementation Method 1
sensors based on the magnetoresistive effect. Anisotropic magnetoresistive (AMR) and giant magnetoresistive (GMR) sensors are particular examples of sensor types based on the magnetoresistive effect
Implementation Method 2
sensors based on the Hall effect or the magnetoresistive effect
Data Source
AI summary
A magnetic field sensor assembly for measuring an angular direction of a sensed magnetic field relative to the assembly is disclosed. The sensor assembly includes a sensor of a first type configured to sense an orientation of the sensed magnetic field, a sensor of a second type configured to measure an orientation and a direction of the sensed magnetic field and processing circuitry connected to each of the magnetic field sensors. The processing circuitry being configured to process output signals from the sensor of the first type to determine an uncorrected sensed magnetic field angle and to apply an offset angle to the uncorrected magnetic field angle dependent on a logical combination of signs of output signals from the sensors of the first and second types.