Wireless Charging Polling for NFC Tag Detection
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Solution Overview
Problem
Conventional wireless charging systems, such as those adhering to the A4WP standard, fail to detect small NFC devices and RFID tags effectively, leading to potential damage or fire hazards due to their inability to distinguish between intended charging devices and nearby sensitive objects within the magnetic field.
Innovation Solution
A modified wireless charging system that progressively increases polling signal power at 13.56 MHz frequency to detect NFC tags, allowing for incremental power steps and extended detection duration, enabling safe identification of proximal tags without causing damage, and switching back to 6.78 MHz for charging if no tag is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional A4WP wireless charging systems use magnetic field for power transfer, then charging efficiency is improved, but nearby sensitive objects such as NFC tags and RFID devices may be damaged or cause fire hazards
Solution Approach 1:
The system performs NFC polling detection before initiating A4WP charging power transfer. By detecting the presence of NFC tags or RFID devices in advance using a separate detection coil, the system can prevent harmful magnetic field exposure to sensitive objects before charging begins, thus avoiding damage or fire hazards while maintaining charging efficiency when safe to proceed
Solution Approach 2:
The patent introduces a separate NFC detection coil as an intermediary component that operates independently from the A4WP charging coil. This detection coil serves as a mediator to identify sensitive objects in the vicinity before full power charging starts, allowing the system to differentiate between intended charging devices and sensitive objects that should not be exposed to high-power magnetic fields
2Measurement precision
If the system increases polling signal power to detect NFC tags, then detection capability is improved, but risk of damaging the NFC tags increases
Solution Approach 1:
The system uses a separate NFC detection coil that operates at low power specifically for detection purposes, rather than using the full-power A4WP charging coil. This partial action approach allows the system to perform detection with minimal power exposure to NFC tags, improving detection capability while avoiding damage. The detection function is separated from the charging function to enable safe polling
Solution Approach 2:
The system changes the operational parameters by using a dedicated detection coil with different characteristics than the charging coil. The detection coil is optimized for low-power NFC frequency operation, allowing the system to adjust power levels and frequency parameters specifically for safe NFC tag detection without affecting the main charging performance
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 system effectively detects NFC tags in less than 200 ms, preventing overheating and potential fires, while ensuring safe operation by ceasing power transfer when sensitive devices are present, thus enhancing safety and charging uniformity.
Implementation Method 1
PTUs of A4WP use an induction coil to generate a magnetic field from within a charging base station, and a second induction coil in the PRU (i.e., portable device) takes power from the magnetic field
Implementation Method 2
a second induction coil in the PRU (i.e., portable device) takes power from the magnetic field and converts the power back into electrical current to charge the battery
Implementation Method 3
Magnetic resonance coupling is the near field wireless transmission of electromagnetic energy between two coils that are tuned to resonate at the same frequency
Data Source
AI summary
The disclosure relates to a method, apparatus and system to wirelessly charge a device without creating fire hazard or other risks to nearby sensitive objects. An exemplary embodiment includes a memory circuitry and a chipset. The chipset communicates with the memory circuitry and is configured to selectively communicate with one of a wireless charging module and an NFC module to detect presence of the sensitive device. The chipset can be further configured to: transmit a first polling signal at a first power level for a first duration and detect a response from the sensitive device; if no response is detected during the first duration, transmit a second polling signal at a second power level for a second duration; cease polling signal transmission if response is received to either the first or the second polling signals; and engage the wireless charging module to charge the proximally located wireless device if no response is detected from the sensitive device during the first or the second duration.