XMR Angle Sensor Startup Verification via Excitation Current
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Solution Overview
Problem
Current safety mechanisms for XMR angle sensors, such as dual sensor concepts and dual die approaches, fail to verify the correctness of the initial angle value during startup and cannot detect systematic errors or 'magnet loss' issues, which can lead to angle measurement errors.
Innovation Solution
An XMR angle sensor arrangement that includes a sensing area for in-plane magnetic fields, a permanent magnet generating a first in-plane magnetic field component, and an excitation current rail path providing a second in-plane magnetic field component through an excitation signal, allowing for the detection of a predictable change in the magnetic field direction, thereby verifying the sensor's functionality and detecting magnet loss during startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual sensor concepts or dual die approaches are used for sensor redundancy, then sensor reliability is improved, but the ability to detect systematic errors and magnet loss during startup deteriorates
Solution Approach 1:
The patent applies preliminary action by performing a self-test measurement before normal operation begins. The excitation current is applied to generate a known magnetic field change, and the sensor response is evaluated to verify correctness before the system starts up, enabling detection of systematic errors and magnet loss that would otherwise go unnoticed
Solution Approach 2:
The patent implements feedback by comparing the actual sensor measurement against an expected value derived from a known excitation signal. The evaluation circuit receives both the sensor output and the excitation signal, computes expected measurements, and compares them to detect deviations indicating systematic errors or magnet loss
2Difficulty of detecting and measuring
If excitation current rail path is added for safety mechanism, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the excitation current rail path to serve multiple functions: it generates a known magnetic field for self-testing, provides a reference signal for comparison, and enables detection of both systematic errors and magnet loss. This multi-functional approach adds detection capability without proportionally increasing complexity
Solution Approach 2:
The patent merges the excitation current rail path with the existing sensor structure, integrating the safety mechanism into the conventional sensor design. The evaluation circuit combines information from the sensor output and excitation signal to perform comprehensive error detection, merging multiple detection functions into a unified system
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 solution enables the reliable verification of the initial angle value and detection of magnet loss during startup, ensuring the correctness of the magnetic field strength and direction, thus enhancing the safety and reliability of XMR angle sensor measurements.
Implementation Method 1
a permanent magnet, which is rotatably arranged with respect to the XMR angle sensor to generate a first in-plane magnetic field component in the sensing area of the XMR angle sensor
Implementation Method 2
an excitation current provider configured to provide the excitation current rail path with an excitation signal having an excitation signal strength, wherein the excitation signal strength of the excitation signal is chosen to generate a second in-plane magnetic field component in the sensing area of the XMR angle sensor
Implementation Method 3
an XMR angle sensor having a sensing area for sensing an in-plane magnetic field and for outputting a sensor signal based on the in-plane magnetic field component sensed in the sensing area
Data Source
AI summary
An XMR angle sensor arrangement with a safety mechanism comprises an XMR angle sensor having a sensing area for sensing an in-plane magnetic field and for outputting a sensor signal based on the in-plane magnetic field component sensed in the sensing area; a permanent magnet, which is rotatably arranged with respect to the XMR angle sensor to generate a first in-plane magnetic field component in the sensing area of the XMR angle sensor; an excitation current rail path, which is arranged proximate to the sensing area of the XMR angle sensor; and an excitation current provider configured to provide the excitation current rail path with an excitation signal having a excitation signal strength, wherein the excitation signal strength of the excitation signal is chosen to generate a second in-plane magnetic field component in the sensing area of the XMR angle sensor which results, due to a super position of the first and second in-plane magnetic field components, in an expected change of the direction of the resulting in-plane magnetic field component, wherein the XMR angle sensor arrangement is correctly functioning when the sensed change of direction of the resulting in-plane magnetic field component due to the excitation signal corresponds to the expected change of direction of the resulting in-plane magnetic field component.