Magnetic Sensor Diagnostic Pin for Target Placement Verification
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Solution Overview
Problem
Magnetic-field sensors face challenges in accurately detecting the position and rotational parameters of targets, particularly when the target is a gear-toothed object, due to variations in tooth spacing and shape, which can lead to improper signal separation and functionality issues.
Innovation Solution
An integrated circuit (IC) with magnetoresistance circuitry, analog circuitry, digital circuitry, and diagnostic circuitry, including a multiplexor, that converts magnetic field signals into channel signals and output signals indicating speed and rotational direction, and provides a test signal to verify the distance and tooth configuration compliance using ADC codes and range/offset parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic-field sensor uses standard magnetoresistance circuitry to detect target position, then the basic detection function is achieved, but the sensor cannot accurately detect targets with varying tooth spacing and shapes due to signal separation issues
Solution Approach 1:
The patent implements a feedback mechanism where the sensor output is monitored and compared against expected signal characteristics. When signal separation falls outside predefined ranges, the system generates diagnostic indicators that feedback to the control processor, enabling real-time adjustment and compensation for different target configurations.
Solution Approach 2:
The patent dynamically adjusts signal processing parameters including gain, offset, and filtering characteristics based on detected signal characteristics. The system modifies these parameters in real-time to optimize detection accuracy for different target types, tooth spacings, and shapes, allowing the same hardware to adapt to varying measurement conditions.
2Reliability
If the sensor operates without diagnostic assessment capabilities, then the device complexity is reduced, but the system cannot verify proper target placement or detect installation errors
Solution Approach 1:
The patent combines the primary detection function with diagnostic assessment capabilities into a single integrated sensor unit. The diagnostic circuitry shares resources with the main detection circuit, including analog-to-digital converters and signal processing pathways, thereby implementing comprehensive monitoring without proportionally increasing overall device complexity.
Solution Approach 2:
The sensor performs self-diagnosis by automatically monitoring its own output signals and comparing them against expected ranges. The diagnostic circuitry assesses signal validity, detects placement errors, and generates status indicators without requiring external testing equipment, enabling the system to self-verify proper operation and target installation.
3Loss of information
If the sensor provides full ADC code range output, then the signal resolution is maximized, but the system cannot provide diagnostic information about signal validity or target placement
Solution Approach 1:
The patent segments the ADC output into multiple functional channels: one channel provides the full-resolution measurement data for position detection, while separate diagnostic channels provide validity assessment and placement verification information. This segmentation allows simultaneous delivery of high-resolution measurement data and diagnostic status information without compromising either function.
Solution Approach 2:
The patent implements multi-functionality by having the same sensor hardware and signal processing circuitry serve dual purposes: generating high-resolution position data and simultaneously providing diagnostic assessment. The diagnostic functions reuse existing ADC resources and signal pathways, enabling the system to extract multiple types of information from the same physical measurements without requiring separate dedicated circuits.
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
Enables accurate detection of target position and rotational parameters, ensuring proper signal separation and functionality by determining valid tooth configurations and adjusting ADC codes to enhance signal-to-noise ratio, thus improving the reliability of magnetic-field sensors in various applications.
Implementation Method 1
a first magnetoresistance circuitry configured to receive a magnetic field signal from a target, and configured to convert the magnetic field signal received to a first channel signal; a second magnetoresistance circuitry configured to receive the magnetic field signal from the target, and configured to convert the magnetic field signal received to a second channel signal
Data Source
AI summary
In one aspect, an integrated circuit (IC) includes a magnetic-field sensor. The magnetic field sensor includes a first and second magnetoresistance circuitries configured to receive a magnetic field signal from a target and convert the magnetic field signal received to a first signal and second signal; analog circuitry configured to receive the first and second signals; digital circuitry configured to receive a first and second analog output signals from analog circuitry and to convert the first and second analog output signals to a first and second digital signals representing a first and second channel output signals; and diagnostic circuitry configured to receive, from the digital circuitry, an input signal related to a separation of the first and second channel output signals, and configured to provide a test signal at a pin of the IC indicating whether a distance between the IC and the target complies with at least one rule.