Magnetic-Field Sensor Test Pin for ADC Range and Offset Control
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Solution Overview
Problem
Magnetic-field sensors face challenges in accurately detecting the rotational speed and direction of ferromagnetic targets, particularly when the target is not properly aligned or has an invalid tooth configuration, leading to insufficient signal separation and improper function.
Innovation Solution
An integrated circuit (IC) with magnetoresistance circuitry, analog circuitry, digital circuitry, and diagnostic circuitry that includes a test pin to output ADC codes, allowing for determination of range and offset parameters, ensuring proper target alignment and valid tooth configuration, thereby enhancing signal separation and sensor functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic-field sensor uses standard ADC output pins only, then the rotational speed and direction can be detected, but the range and offset parameters cannot be adjusted or tested, leading to insufficient signal separation when target alignment is improper
Solution Approach 1:
The test pin is designed to serve multiple functions: it can output ADC codes for range and offset parameter testing, and can also be used for diagnostic purposes. This multi-functionality allows the same hardware resource to provide both standard rotation detection and advanced parameter adjustment capabilities, resolving the contradiction between measurement precision and adaptability
2Reliability
If the sensor operates without a test pin for parameter control, then the device complexity is reduced, but the ability to determine proper target alignment and valid tooth configuration is lost
Solution Approach 1:
The test pin acts as an intermediary interface between the digital circuitry and the external testing equipment. It provides a dedicated output path for ADC codes that enables parameter verification without requiring complex internal circuitry modifications. This intermediary approach enhances reliability by enabling target alignment verification while maintaining relatively simple device architecture
3Adaptability or versatility
If the magnetic-field sensor lacks diagnostic circuitry, then the device complexity is minimized, but the functionality to ensure valid tooth configuration and proper alignment cannot be implemented
Solution Approach 1:
The diagnostic functionality is extracted as a separate circuit module that can be independently configured and tested. The test pin provides a dedicated output for diagnostic purposes, separating the parameter testing function from the main rotation detection pathway. This extraction approach enables enhanced adaptability for diagnostic capabilities while keeping the overall device complexity manageable through functional separation
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 enables accurate detection of rotational speed and direction by determining range and offset parameters, ensuring proper target alignment and valid tooth configuration, thus improving the magnetic-field sensor's functionality and reliability.
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 digital circuitry that includes a first and second analog-to-digital converter (ADC). The digital circuitry is configured to receive a first and second analog output signals and, using the first and second ADC, configured to convert the first and second analog output signals to a first and second digital signals. The magnetic-field sensor also includes diagnostic circuitry configured to receive, from the digital circuitry, an input signal related to the first and/or the second digital signals and configured to provide a test signal at a pin of the IC. In response to a range parameter, the diagnostic circuitry is further configured to provide the test signal comprising a range of codes from the first and/or the second ADC corresponding to the range parameter.