NFC Antenna Switching for Wireless Charging Interference
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Solution Overview
Problem
The integration of wireless charging and Near Field Communication (NFC) functions in portable terminals poses a risk of interference, particularly when using magnetic field coupling at 6.78 MHz, where harmonic components can exceed the rating of NFC IC chips, leading to potential failures.
Innovation Solution
Incorporating a switch or impedance variable circuit between the NFC antenna and circuit to disconnect the NFC during wireless charging, and using a different communication frequency band to prevent interference, ensuring reliable NFC operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If magnetic field coupling at 6.78 MHz is used for wireless charging, then wireless charging function is enabled, but harmonic components at 13.56 MHz interfere with NFC operation causing IC chip failure
Solution Approach 1:
The controller detects whether the terminal is in a wireless charging state before NFC communication occurs, and proactively switches the NFC antenna connection state to prevent harmful electromagnetic induction. This preliminary detection and preventive switching avoids the harmful effect before it can damage the NFC IC chip.
Solution Approach 2:
The NFC antenna switch acts as an intermediary component that controls the connection between the NFC antenna and the NFC IC chip. By switching the connection state based on wireless charging status, it mediates between the wireless charging function and NFC communication, preventing harmful interactions while allowing both functions to operate when appropriate.
2Ease of operation
If NFC antenna is always connected for data communication, then NFC communication availability is improved, but interference from wireless charging electromagnetic induction cannot be avoided
Solution Approach 1:
The NFC antenna connection state is made dynamic rather than static. The switch controlled by the controller adjusts the connection state based on real-time wireless charging status, allowing the system to adapt between maintaining NFC availability and preventing electromagnetic interference as conditions change.
Solution Approach 2:
The system applies preliminary anti-action by detecting the wireless charging state and switching the NFC antenna connection to disconnected state before harmful electromagnetic induction can occur. This preventive measure counteracts the potential harmful effect before it manifests.
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
Prevents NFC circuit failures by disconnecting the NFC antenna during wireless charging, allowing safe operation and reliable data communication, even when the portable terminal is near a wireless charger.
Implementation Method 1
the electric power may be transmitted through electromagnetic induction between a transmitting coil arranged in the wireless charger and the power receiving coil arranged in the portable terminal apparatus
Implementation Method 2
Communication is carried out by using electromagnetic induction between an antenna for communication arranged in the transmission apparatus and an antenna for communication arranged in the portable terminal apparatus
Data Source
AI summary
A portable terminal apparatus according to an embodiment includes a power supply and a power receiving circuit that wirelessly receives electric power for charging the power supply. A first communication circuit transmits and receives information relating to receiving the electric power. A second communication circuit includes a communication antenna, a near field radio communication circuit and a switch arranged between the communication antenna and the near field radio communication circuit. The second communication circuit is selectively configured to communicate with a separate terminal device via near field radio communication. A controller controls the switch to disconnect the communication antenna from the near field radio communication circuit in response to the first communication circuit receiving the information relating to receiving the electric power.