Dual Hall Sensor Rotation Angle Determining Unit
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Solution Overview
Problem
Existing integrated rotation angle determining sensor units in motor vehicles are not sufficiently fail-safe, cost-effective, and prone to interference from static magnetic fields, particularly in safety-critical applications like determining the rotation angle of a steering wheel.
Innovation Solution
A dual Hall sensor system with redundant design, where two semiconductor layers with monolithically integrated Hall sensors and activation/evaluation units are arranged concentrically around the rotation axis, along with magnetoresistive sensors, to provide high resolution and compensation for static interference fields, and are housed in a shared IC with a metal carrier to reduce mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single Hall sensor system is used, then the device complexity is reduced, but the reliability is insufficient for safety-critical applications
Solution Approach 1:
The patent implements a redundant Hall sensor system where a second Hall sensor system is integrated alongside the first Hall sensor system on the same semiconductor layer. This redundancy provides beforehand cushioning against sensor failures, ensuring continues operation even if one sensor system fails, which is critical for safety applications like steering angle detection.
Solution Approach 2:
The patent merges two Hall sensor systems into a single integrated semiconductor layer, combining the functionality of multiple sensors and their evaluation circuits into one unified structure. This merging approach achieves the reliability benefits of redundancy while minimizing the increase in device complexity through integrated circuit design.
2Measurement precision
If magnetic field sensors are used to determine shaft position, then the measurement capability is achieved, but the system is susceptible to static magnetic interference
Solution Approach 1:
The patent employs differential evaluation of signals from multiple Hall sensors arranged in specific patterns. By comparing the outputs of sensors positioned at different locations around the shaft, the system can detect and compensate for static magnetic interference through feedback mechanisms that distinguish between rotational signal changes and constant interference fields.
Solution Approach 2:
The Hall sensors are arranged in asymmetric patterns relative to the shaft axis, with sensors positioned at specific angular intervals. This asymmetric arrangement, combined with differential signal processing, enables the system to reject symmetric static interference fields while maintaining sensitivity to the rotational position signal.
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
The solution achieves high resolution in determining rotation angles while effectively suppressing static magnetic interference, ensuring reliability and cost-effectiveness, particularly in safety-critical applications by using redundant Hall sensor systems and magnetoresistive sensors.
Implementation Method 1
A first Hall sensor system of a monolithic design is formed in the first semiconductor layer... A second Hall sensor system of a monolithic design is formed in the second semiconductor layer... The three Hall sensors of the first Hall sensor system are arranged along a first circle section
Implementation Method 2
If additional structural elements, in particular sensors for measuring mechanical stresses and/or other types of magnetic field sensors, are provided as part of the rotation angle determining sensor unit
Data Source
AI summary
An integrated rotation angle determining sensor unit in a measuring system for determining a rotation angle, comprising a shaft, rotatable around a rotation axis, having a transducer, a first semiconductor layer designed as a die being provided, which has an upper side arranged perpendicularly to the rotation axis and an underside and a first Hall sensor system monolithically formed in the first semiconductor layer, and a second semiconductor layer designed as a die being provided, which has an upper side arranged perpendicularly to the rotation axis and an underside and a second Hall sensor system monolithically formed in the second semiconductor layer, each Hall sensor system including at least one first Hall sensor and a second Hall sensor and a third Hall sensor.