Magnetic Field Sensor Using Current Spinning Phase Sequences
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic field sensors face challenges in providing high angular accuracy and speed, particularly in applications where the angle of the magnetic field is rapidly changing, due to errors associated with temperature variations and mechanical stress.
Innovation Solution
The method involves using a plurality of magnetic field sensing elements configured to generate x-y output signals, with sequential selection and current spinning phases to produce a sequenced-chopped signal representative of the magnetic field angle, employing randomly or pseudo-randomly selected phase sequences to reduce angular errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic field sensing elements are used, then the device structure is simple, but the angular accuracy deteriorates due to temperature variations and mechanical stress errors
Solution Approach 1:
The magnetic field sensor is divided into multiple sensing elements (first, second, third, and fourth elements) arranged in a segmented configuration. Each element contributes to measuring different components of the magnetic field, allowing for more accurate angle determination through combination of multiple measurements rather than relying on a single sensing element.
Solution Approach 2:
The patent implements periodic switching between different sensing elements using switch networks. The first and second sensing elements are switched periodically to generate first and second output signals, while the third and fourth elements are switched periodically to generate third and fourth output signals. This periodic action enables temporal multiplexing of the sensing elements, improving measurement accuracy through sequential sampling while managing device complexity.
2Speed
If the magnetic field angle changes rapidly, then the application requires high speed response, but the angular accuracy deteriorates due to dynamic errors
Solution Approach 1:
The periodic switching between sensing elements is designed with specific timing to capture rapid changes in magnetic field angle. By switching elements at optimized intervals, the system can track fast-changing angles while maintaining accuracy through the periodic sampling and combination of signals from multiple elements.
Solution Approach 2:
The patent combines output signals from multiple sensing elements through a processing network that effectively cancels dynamic errors. The feedback mechanism involves using the differential signals from the segmented elements to compensate for each other's errors, particularly eliminating third-order harmonic errors that occur during rapid angle changes.
3Measurement precision
If temperature variations occur, then environmental conditions change, but the angular accuracy deteriorates due to temperature-induced errors
Solution Approach 1:
The segmented configuration of four sensing elements allows for differential measurement techniques that cancel temperature-induced errors. By measuring with multiple elements and combining their outputs, the system can distinguish between actual magnetic field changes and temperature drift effects.
Solution Approach 2:
The signal processing network implements error cancellation that accounts for temperature variations. The combined output signals from the switched sensing elements create a feedback mechanism that compensates for temperature-induced offsets and drift, maintaining angular accuracy across varying thermal conditions.
4Measurement precision
If mechanical stress is applied, then the sensing element experiences stress, but the angular accuracy deteriorates due to stress-induced errors
Solution Approach 1:
The use of multiple segmented sensing elements allows for spatial distribution of stress effects. By combining measurements from elements at different positions, the system can cancel out stress-induced errors that affect individual elements differently, maintaining overall measurement accuracy under mechanical load.
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 approach significantly enhances the angular accuracy and speed of magnetic field sensor outputs, effectively mitigating errors caused by temperature and mechanical factors, thereby improving the performance in dynamic applications.
Implementation Method 1
A first vertical Hall element can be provided having a first output signal responsive to a magnetic field in an x-y plane
Data Source
Figure 1~1A
Figure 2
Figure 3
AI summary
A magnetic field sensor can use a variety of different current spinning phase sequences in order to suppress repetitive noise and to reduce errors of the magnetic field sensor. An associated method is described.