Magnetic Field Sensor Shunt Layout for Accessory Magnet Detection
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Solution Overview
Problem
Electronic devices face limitations in detecting magnets in accessory devices due to proximity issues, leading to false triggers and compatibility challenges, and there is a need to prevent unwanted detection of internal magnets while allowing detection of external magnets for accessory compatibility.
Innovation Solution
Incorporating a shunt assembly that alters the magnetic field emitted by internal device magnets to prevent detection by the magnetic field sensor, while allowing detection of external magnets, and using this detection to deactivate the display and microphone as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic field sensor is placed in proximity to internal magnets to detect accessory magnets, then the detection sensitivity is improved, but false triggers occur due to detection of internal magnets
Solution Approach 1:
A shunt assembly is introduced as an intermediary component between the internal magnets and the magnetic field sensor. The shunt assembly selectively redirects magnetic flux to block the sensor from detecting internal magnets while allowing detection of external accessory magnets, thereby resolving the contradiction between detection sensitivity and false trigger prevention
Solution Approach 2:
The shunt assembly is positioned at specific locations around the magnetic field sensor to create localized magnetic flux redirection. This selective positioning allows the sensor to maintain high sensitivity to external magnets while being protected from internal magnet interference in specific directional zones
2Adaptability or versatility
If multiple sensors are added to detect various accessory devices, then accessory compatibility is improved, but device complexity increases
Solution Approach 1:
The magnetic field sensor is designed to perform multiple detection functions by detecting magnetic fields from different accessory devices (e.g., Bixby chip, S-Pen, earphones) through a single sensor location. The shunt assembly enables this universal detection capability while maintaining a single sensor configuration, avoiding the need for multiple specialized sensors
3Use of energy by moving object
If the battery dimensions are increased for longer usage time, then energy capacity is improved, but the number of available sensor locations is reduced
Solution Approach 1:
The shunt assembly acts as a mediator that enables the magnetic field sensor to be positioned in locations that would otherwise be unsuitable due to proximity to internal magnets. This allows flexible sensor placement in space not occupied by the larger battery, maintaining detection capability while accommodating increased battery capacity
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
Enables compatible detection of magnets in various accessory devices without false triggers, enhances user privacy by disabling the microphone when an accessory covers the display, and improves the signal-to-noise ratio for accurate magnetic field detection.
Implementation Method 1
a shunt assembly that alters the magnetic field emitted by internal device magnets to prevent detection by the magnetic field sensor
Implementation Method 2
a magnetic field sensor configured to generate a switching signal based upon detection of at least a threshold magnetic field
Data Source
AI summary
An electronic device is disclosed. The electronic device includes a device magnet designed to magnetically couple with an accessory device magnet. The electronic device further includes a display assembly and a magnetic field sensor configured to detect the accessory device magnet, thereby providing an indication that the accessory device is covering the display assembly. The electronic device further includes a shunt assembly designed to reduce the magnitude of the magnetic field of the device magnet, as determined by the magnetic field sensor, while allowing the magnetic field from the accessory device to sufficiently reach the magnetic field sensor. As such, the magnetic field sensor can be placed near the device magnet without triggering the magnetic field sensor. The electronic device may further include a microphone. Communication between the microphone and an integrated circuit can cease based on the magnetic field sensor detecting the accessory device magnet.