Magnetic Angle Switch Circuit Immune to Temperature Variations
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Solution Overview
Problem
Conventional magnetic switch circuits, such as brake light sensors, are sensitive to sensitivity and offset errors, as well as temperature variations, due to their reliance on absolute magnetic field strength measurements.
Innovation Solution
A magnetic angle switch circuit that determines the angle of a magnetic field instead of its absolute value, using trigonometric functions and magneto-resistive elements or Hall sensors, to produce a binary output immune to changes in magnetic field strength and temperature, with adjustable angular thresholds and orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic switch circuits use absolute magnetic field strength measurements, then the switching function can be implemented, but the circuit becomes sensitive to sensitivity and offset errors as well as temperature variations
Solution Approach 1:
The patent changes the measurement parameter from absolute magnetic field strength to magnetic field angle. By measuring the angle of the magnetic field vector rather than its magnitude, the system becomes immune to temperature-induced sensitivity changes and offset errors, as these affect the field strength but not its directional angle.
Solution Approach 2:
Instead of measuring the magnetic field strength directly, the patent inverts the approach by measuring the angle of the magnetic field. This inversion transforms a measurement that is sensitive to temperature and sensitivity errors into one that is inherently immune to these factors.
2Ease of operation
If Hall sensors are used to detect magnetic field changes, then brake pedal movement can be monitored, but the output signal becomes dependent on magnetic field strength which introduces sensitivity errors
Solution Approach 1:
The patent changes the output parameter of the Hall sensor system from magnetic field strength to magnetic field angle. By processing the Hall sensor signals to extract the angle of the magnetic field vector, the system maintains its ability to monitor brake pedal movement while eliminating sensitivity and offset errors from the output signal.
3Extent of automation
If magnetic field strength is used to control switch output, then the switch function is achieved, but the system becomes vulnerable to sensitivity and offset errors
Solution Approach 1:
The patent inverts the control parameter from magnetic field strength to magnetic field angle. This inversion allows the switching function to be maintained while achieving immunity to sensitivity and offset errors, as the angle measurement is not affected by these factors.
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 magnetic angle switch circuit provides robust and accurate switching points with improved temperature stability and reduced sensitivity to errors, enabling reliable operation across a wide range of angles and temperatures.
Implementation Method 1
a magnetic sensor circuit which is configured to determine a sensor signal indicative of an angle of a magnetic field
Implementation Method 2
The magneto-resistors may be magneto-resistive elements based on anisotropic magnetoresistance (AMR), giant magnetoresistance (GMR), or preferably based on tunnel magnetoresistance (TMR)
Implementation Method 3
a Hall sensor, a magnetic field that changes in dependence on the movement
Data Source
AI summary
A magnetic angle switch circuit including a magnetic sensor circuit configured to determine a sensor signal indicative of an angle of a magnetic field; and a switch circuit configured to compare the sensor signal against a threshold signal indicative of a predefined angular threshold, and output a binary signal indicative of whether the angle of the magnetic field exceeds or falls below the predefined angular threshold.