Solid-State Magnetic Switch Circuit for Axis-Specific Sensing
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Solution Overview
Problem
Reed switches are limited by their mechanical nature, leading to size constraints, reliability issues such as sticking or demagnetization, vulnerability to shock and vibration, and inability to sense magnetic fields along specific axes, requiring external circuits for debounce and lacking configurability.
Innovation Solution
A magnetically-activated solid state switch comprising a magnetic field sensor, a solid state output switch, control circuitry, a charge pump, and a low-power regulator, which implements ON/OFF logic and periodically turns off to maintain charge for magnetic field sensing, allowing for precise control and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a reed switch is used as a magnetic switch, then magnetic field sensing is achieved, but the device size is relatively large and size reduction options are limited
Solution Approach 1:
The patent replaces the mechanical reed switch system with a solid-state magnetic field sensor system. The sensor uses magnetic field detection elements (such as Hall effect sensors or magnetoresistive sensors) to sense the magnetic field and control the switching operation electronically, eliminating the need for mechanical moving parts and the glass enclosure, thereby reducing size while improving reliability.
2Adaptability or versatility
If a reed switch is used, then magnetic field sensing is achieved, but the device cannot be configured to sense along specific axes and senses in all three dimensions
Solution Approach 1:
The patent employs multiple magnetic field sensors arranged in specific spatial orientations (e.g., one sensor for vertical axis detection, another for horizontal axis detection). Each sensor is positioned and oriented to detect magnetic field components along specific axes, allowing the system to be configured for unidirectional or multidirectional sensing by selectively using the output of specific sensors.
3Reliability
If a reed switch is used under shock and vibration conditions, then magnetic field sensing is achieved, but contact bounce occurs requiring external debounce circuits
Solution Approach 1:
The patent replaces the mechanical contact-based switching mechanism with a solid-state electronic switching mechanism. The magnetic field sensor outputs a signal that is processed by control circuitry to drive a solid-state switch (such as a transistor or MOSFET), eliminating mechanical contacts and thereby eliminating contact bounce entirely, with no need for external debounce circuits.
4Reliability
If a reed switch is enclosed in plastic to improve durability, then shock and vibration resistance is improved, but cost and size increase
Solution Approach 1:
The patent eliminates the need for a protective glass or plastic enclosure by replacing the entire mechanical reed switch structure with a solid-state magnetic field sensor and electronic circuitry. The solid-state components are inherently more resistant to shock and vibration, and the integrated circuit design allows for compact packaging without requiring additional protective housing.
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 solid state switch is durable, resistant to shock and vibration, configurable to sense magnetic fields along multiple axes, and does not suffer from sticking or mechanical failure, enabling reliable and efficient magnetic field detection.
Implementation Method 1
a magnetic field sensor configured to make one or more magnetic field measurements and produce corresponding output signals; The magnetic field sensor may include one or more Hall effect elements.
Data Source
AI summary
Magnetically-activated solid state switches can include a magnetic field sensor, control circuitry configured to implement a comparison or ON/OFF logic, an output switch, a rectifier, power regulator, and charge pump, as shown. A magnetically-activated solid state switch can include a sensor bias or driver block. An analog front end may be present to amplify and/or condition the output signals produced by magnetic field sensor. Terminals can accommodate a unidirectional DC input signal or a bidirectional or AC input signal. In the ON state, the solid state output switch is configured by the control circuitry to turn OFF at a periodic rate to maintain sufficient charge to allow the solid state magnetic field sensor to sense a magnetic field. In the OFF state, the low-power regulator can periodically turn on and provide power to the magnetic field sensor for taking a magnetic field measurement.