Multi-Chip NFC Antenna Detuning for Charging Without Interference
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Solution Overview
Problem
Existing NFC systems face interference issues when more than two NFC chips share the same physical communication channel, particularly during wireless charging, which can harm non-wireless charging capable NFC devices.
Innovation Solution
An NFC device with two inductively coupled antennas and matching networks, featuring a detuning circuit that adjusts resonance frequencies to prevent interference, allowing one NFC chip to charge while the other communicates or vice versa, based on battery voltage availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple NFC chips share the same physical communication channel for wireless charging, then wireless charging capability is improved, but communication between NFC chips is disturbed and harmful signal levels are generated
Solution Approach 1:
The patent divides the single NFC communication channel into multiple independent channels by introducing frequency separation. Each NFC chip operates on a distinct frequency (e.g., 13.56 MHz for NFC, 6.78 MHz for wireless charging), effectively segmenting the communication spectrum to avoid interference between wireless charging and NFC operations
Solution Approach 2:
The patent changes the operating frequency parameter of different NFC chips to resolve conflicts. By assigning different frequency parameters to different NFC chips (one for NFC communication, another for wireless charging), the system enables simultaneous operation without harmful signal levels or communication disturbances
2Power
If one NFC chip is activated for wireless charging with high signal levels, then wireless charging efficiency is improved, but other NFC devices not designed for wireless charging are harmed
Solution Approach 1:
The patent segments the NFC chip population into different functional groups operating at different frequencies. The wireless charging NFC chip operates at 6.78 MHz while standard NFC chips operate at 13.56 MHz, creating frequency-based isolation that protects non-WLC devices from harmful high-power signals
Solution Approach 2:
The patent introduces frequency as an intermediary parameter that mediates between wireless charging power transmission and NFC communication. By using frequency separation, high-power wireless charging can occur without directly interfering with standard NFC operations, as the two operations occur in different frequency domains
3Adaptability or versatility
If more than two NFC chips are inductively coupled to share the same physical communication channel, then system functionality is improved, but communication between particular NFC chips is disturbed
Solution Approach 1:
The patent segments the communication spectrum into multiple frequency bands, allowing more than two NFC chips to operate simultaneously without interference. Each chip is assigned a specific frequency, creating independent communication channels that maintain reliability even as system complexity increases
Solution Approach 2:
The patent adds the frequency dimension to the NFC communication system. Instead of sharing the same frequency channel, chips operate at different frequencies, effectively moving the problem from a one-dimensional (single channel) to a multi-dimensional (multiple frequency channels) space, thereby enabling reliable multi-chip operation
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 simultaneous operation of multiple NFC chips without disrupting communication, ensuring efficient wireless charging and data transfer by dynamically managing resonance frequencies based on battery status.
Implementation Method 1
a first NFC antenna and a second NFC antenna, which are inductively coupled to each other
Implementation Method 2
the corresponding antenna circuits are usually operated at the same resonance frequency, which results in a maximum electromagnetic coupling
Implementation Method 3
a first detuning circuit coupled to the first antenna and configured to, when activated, detune a first resonant circuit including the first antenna and the first matching circuit
Data Source
Figure 1~3
Figure 4~5
Figure 6A~6B
AI summary
An NFC device is described herein. According to one exemplary embodiment, the NFC device includes a first NFC antenna and a second NFC antenna, which are inductively coupled to each other (and, during operation, also to the antenna of a further NFC device). The NFC device further includes a first NFC circuit coupled to the first antenna via a first matching network and a second NFC circuit coupled to the second antenna via a second matching network. Furthermore, the NFC device includes a first detuning circuit coupled to the first antenna and configured to, when activated, detune a first resonant circuit formed by the first antenna, the first matching circuit and the first detuning circuit.