Wireless Charger Object Detection for NFC Tag Safety
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Solution Overview
Problem
Wireless charging systems often cause heating and potential damage to NFC tags and devices due to thermal issues, and existing solutions disrupt user experience by summarily stopping charging when an NFC-enabled device is detected, failing to distinguish between compatible and non-compatible devices.
Innovation Solution
A wireless power transmitting unit (PTU) that uses a combination of capacitive sensors, Foreign Object Detection, NFC readers, and Bluetooth Low Energy (BLE) responses to differentiate between NFC tags, A4WP compliant phones, and non-compliant devices, allowing for controlled charging decisions to prevent damage while maintaining user experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wireless charging is performed on NFC tags, then charging function is provided, but heating and damage occur to the NFC tags
Solution Approach 1:
The system performs Foreign Object Detection (FOD) and NFC reading before initiating wireless charging to identify NFC tags and determine their compatibility with wireless charging, preventing heating and damage by avoiding charging of incompatible tags
Solution Approach 2:
The system continuously monitors charging status and temperature during wireless charging, and can stop or adjust charging when NFC tags overheat or show signs of damage, providing real-time feedback control to prevent harm
2Object-affected harmful factors
If charging is stopped when NFC-enabled device is detected, then damage to NFC tags is prevented, but user experience is disrupted
Solution Approach 1:
The system applies different charging policies to different types of NFC-enabled devices based on their compatibility characteristics, allowing charging for compatible devices while preventing charging for incompatible tags, rather than applying a blanket stop to all NFC devices
Solution Approach 2:
The system changes charging parameters such as power level and charging rate based on device type and compatibility status, providing optimized charging for compatible devices while limiting power to prevent damage to incompatible tags
3Measurement precision
If multiple detection methods are used to distinguish devices, then accurate device differentiation is achieved, but system complexity increases
Solution Approach 1:
The system segments the detection process into distinct stages: FOD stage to detect foreign objects, NFC reading stage to read tags, and device classification stage to categorize devices, making the complex detection process more manageable and systematic
Solution Approach 2:
The system uses NFC reading as an intermediary step between FOD and final device classification, where NFC tags are read and their compatibility is determined before making charging decisions, providing a structured approach to device differentiation
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 solution effectively distinguishes between supported and unsupported devices, preventing damage to NFC tags and phones, ensuring safe charging while allowing compatible devices to charge without disrupting the user experience.
Implementation Method 1
a PTU may include a transmit (Tx) coil, and a PRU may include a receive (Rx) coil. Magnetic resonance wireless charging may employ a magnetic coupling between the Tx coil and the Rx coil.
Implementation Method 2
Magnetic resonance wireless charging may employ a magnetic coupling between the Tx coil and the Rx coil.
Data Source
AI summary
A method of wirelessly charging batteries of devices includes detecting at least two devices being simultaneously present on a charging mat. It is determined, for each of the at least two devices, whether the device is compatible with a wireless charging standard. It is determined, for each of the two devices, whether the device is enabled for a near field communication. Charging of the devices is prevented if at least one of the devices is enabled for a near field communication but not compatible with the wireless charging standard.