Magnetic Field Angle Sensor Low Power Mode Asymmetric Channels
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Solution Overview
Problem
Magnetic field sensors used in automobile control systems face challenges in accurately detecting the position of rotating objects like steering wheels while minimizing power consumption and ensuring safety through redundant channels, as existing systems often result in high power consumption and inaccuracies due to long sleep periods during low power mode operations.
Innovation Solution
A magnetic field sensor configuration using two channels with magnetic field sensing elements offset by a predetermined angle, including a converter circuit and processor to compare signals and determine the target angle with increased precision, allowing longer sleep times while maintaining accuracy and safety through redundant channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic field sensors use redundant identical circuits to meet safety specifications, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies asymmetry by using two channels with magnetic field sensing elements offset by a predetermined non-zero angle (e.g., 45 degrees) rather than using identical redundant circuits. This asymmetric configuration allows the system to meet safety specifications through diverse measurement perspectives while reducing overall device complexity compared to fully redundant identical circuit implementations.
2Use of energy by moving object
If magnetic field sensors activate portions of the device for short awake time intervals during each clock cycle, then power consumption is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent applies preliminary action by performing angle determination using the asymmetric two-channel configuration during brief awake intervals. The system prepares and executes measurements efficiently during these short active periods, leveraging the predetermined angular offset to achieve sufficient precision without requiring extended measurement times, thus maintaining low power consumption.
3Use of energy by moving object
If magnetic field sensors use longer sleep times during low power mode, then power consumption is reduced, but angle detection accuracy deteriorates
Solution Approach 1:
The patent applies parameter changes by utilizing the predetermined angular offset between channels as a key parameter that enables accurate angle determination from limited measurement data. This parameter configuration allows the system to achieve sufficient measurement precision from brief awake intervals, enabling longer sleep times while maintaining acceptable angle detection accuracy.
4Measurement precision
If magnetic field sensors use two channels with sensing elements offset by a predetermined angle, then angle detection precision is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the measurement function across two separate channels, each with its own magnetic field sensing elements oriented at different angles. This segmentation allows the system to achieve improved angle detection precision through multiple measurement perspectives while keeping each individual channel relatively simple, balancing overall device complexity.
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 configuration enables more precise angle detection of rotating objects, reducing power consumption and improving accuracy by allowing longer sleep times during low power mode operations while maintaining the safety benefits of redundant channels.
Implementation Method 1
the magnetic field is typically detected by one or more magnetic field sensing elements, such as Hall effect elements or magnetoresistance elements
Implementation Method 2
the magnetic field is typically detected by one or more magnetic field sensing elements, such as Hall effect elements or magnetoresistance elements
Data Source
AI summary
A magnetic field sensor that detects an angle of a target includes a first channel having first and second magnetic field sensing elements that are orthogonal with respect to each other and produce first and second magnetic field signals, and a second channel having third and fourth magnetic field sensing elements that are orthogonal with respect to each other and produce third and fourth magnetic field signals. The third sensing element is positioned at an angle (e.g., 45-degrees) with respect to the first sensing element. The magnetic field sensor includes a low power mode circuit that uses comparators to compare the first, second, third, and fourth magnetic field signals to a first, second, third, and fourth threshold, respectively. A processor is configured to use an output of the low power mode circuit to determine the angle of the target.