Analog Angle Sensor Digital Feedback Loop Gain Offset Correction
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Solution Overview
Problem
Magnetic field sensors face challenges in accurately detecting rotational angles of targets due to variations in magnetic field sensitivity caused by manufacturing tolerances, aging, and temperature changes, leading to inaccuracies in cosine and sinusoidal projections.
Innovation Solution
A magnetic field sensor system comprising multiple magnetic field sensing elements, analog frontend circuits, and a digital feedback circuit that adjusts gain and offset of sensor signals based on feedback signals generated from peak-to-peak amplitudes and offsets to correct for sensitivity mismatches and temperature variations, allowing for precise rotational angle detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic field sensors are used to detect rotational angles, then rotational angle detection is enabled, but manufacturing tolerances and aging cause sensitivity variations leading to measurement inaccuracies
Solution Approach 1:
The patent implements a feedback mechanism where the sensor output is fed back through a digital-to-analog converter to generate a correction signal. This feedback loop continuously monitors the sensor output and adjusts the input signal to compensate for sensitivity variations caused by manufacturing tolerances and aging, thereby maintaining measurement precision over time.
Solution Approach 2:
The patent dynamically adjusts the input signal parameters (amplitude and phase) based on feedback information. By changing these parameters in response to detected sensitivity variations, the system compensates for drift and maintains accurate rotational angle detection despite manufacturing tolerances and environmental changes.
2Duration of action of stationary object
If magnetic field sensors operate over extended periods, then continuous rotational angle detection is achieved, but temperature changes and aging cause sensitivity drift reducing measurement accuracy
Solution Approach 1:
The feedback mechanism continuously monitors sensor output and adjusts the input signal to compensate for temperature-induced sensitivity drift. This ongoing adjustment ensures that measurement precision is maintained throughout extended operation periods despite environmental variations and aging effects.
Solution Approach 2:
The system performs preliminary calibration and characterization of the sensor's frequency response at different temperatures. This preliminary information is stored and used to predict and compensate for future drift, enabling the system to maintain accuracy during extended operation without requiring continuous real-time calibration.
3Speed
If analog signal processing is used in magnetic field sensors, then real-time signal processing is achieved, but sensitivity mismatches between sensing elements cause projection inaccuracies
Solution Approach 1:
The patent uses feedback to measure the actual output of the sensor and compares it with the expected output based on the input signal. The difference (error signal) is then used to adjust the input signal parameters, compensating for sensitivity mismatches between the cosine and sinusoidal sensing elements while maintaining real-time processing capability.
Solution Approach 2:
The patent replaces complex analog matching circuits with a digital feedback mechanism that uses a digital-to-analog converter to generate correction signals. This substitution allows for more precise compensation of sensitivity mismatches while maintaining real-time processing speed, as digital processing can be performed at higher rates than analog adjustment 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
The system enhances the accuracy of rotational angle detection by compensating for sensitivity mismatches and temperature-induced changes, improving the reliability of magnetic field sensors in various applications.
Implementation Method 1
Magnetic field sensors generally include a magnetic field sensing element and other electronic components. Magnetic field sensors provide an electrical signal representative of a sensed magnetic field.
Implementation Method 2
Various types of magnetic field sensing elements are known, including Hall Effect elements and magnetoresistance (MR) elements.
Implementation Method 3
Various types of magnetic field sensing elements are known, including Hall Effect elements and magnetoresistance (MR) elements.
Data Source
AI summary
An angle sensor comprising: a plurality of magnetic field sensing elements configured to detect a magnetic field and generate a respective plurality of analog magnetic field signals; a plurality of analog frontend circuits each analog frontend circuit associated with a respective magnetic field sensing element; and a digital feedback circuit configured to generate digital magnetic field signals from the plurality of analog magnetic field signals and generate digital error correction values, wherein the plurality of analog frontend circuits are configured to obtain the digital error correction values from the digital feedback circuit, generate analog correction values from the digital error correction values, and apply the analog correction values to the plurality of analog magnetic field signals to generate a plurality of corrected analog magnetic field signals.