Wireless Charging Multiplexer for NFC Tag Coexistence

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Solution Overview

Problem

Conventional wireless charging systems using the Alliance for Wireless Power (A4WP) standards are unable to detect and safely coexist with nearby NFC tags, as they are damaged by the magnetic field used for charging due to the inability to differentiate between power losses from NFC devices and other objects, leading to false detection and potential device damage.

Innovation Solution

The implementation of a wireless charging multiplexer that uses frequency or time multiplexing to detect NFC tags by generating both an A4WP magnetic field for charging and an NFC signal on the same resonator coil, allowing for continuous detection and reduction of the charging field to avoid interference and damage, while maintaining efficient charging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a magnetic field is generated for wireless charging, then charging power is delivered to the device, but NFC tags nearby are damaged due to inability to differentiate power losses

Engineering Contradiction:

Improvecharging powerVSAvoidNFC tag damage

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent segments the detection and charging functions by implementing a two-phase process: first detecting NFC tags during a detection phase before full charging begins, then separately managing charging power delivery. This segmentation allows the system to identify NFC tags and prevent damage by avoiding full power delivery to areas with NFC tags present.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary detection of NFC tags before initiating full wireless charging power delivery. By conducting load detection and NFC tag identification in advance (during beacon intervals or power save states), the system can prepare appropriate power management decisions to prevent NFC tag damage before harmful power levels are reached.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If load detection is performed continuously, then NFC tags can be detected accurately, but charging efficiency decreases due to false detections and power losses

Engineering Contradiction:

ImproveNFC tag detection accuracyVSAvoidcharging efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent implements periodic load detection during specific beacon intervals or power save states rather than continuous detection. This periodic approach reduces false detections and power losses while maintaining adequate NFC tag detection capability, thereby improving charging efficiency without sacrificing detection accuracy.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent utilizes existing beacon intervals and power save states for NFC tag detection purposes, rather than creating separate dedicated detection periods. By leveraging already-present system states for dual purposes (communication/beaconing and NFC detection), the patent avoids additional power consumption and maintains charging efficiency while achieving accurate detection.

Inventive Principle:

Principle #25Self-service

3Object-affected harmful factors

If the magnetic field is reduced when NFC tag is detected, then NFC tag damage is prevented, but charging area coverage is reduced

Engineering Contradiction:

ImproveNFC tag protectionVSAvoidcharging area

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent applies local quality by reducing magnetic field strength specifically in regions where NFC tags are detected, while maintaining full charging power in areas without NFC tags. This localized power management allows the system to protect NFC tags in specific locations while preserving full charging capability in other areas, thus maintaining overall charging area coverage.

Inventive Principle:

Principle #3Local quality

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 accurate detection of NFC tags without disrupting wireless charging, preventing false detections and protecting NFC devices from damage by reducing the magnetic field when an NFC tag is detected, thus ensuring safe and effective coexistence with wireless charging systems.

Implementation Method 1

Wireless charging or inductive charging uses a magnetic field to transfer energy between two devices. PTUs of A4WP use an induction coil to generate a magnetic field from within a charging base station

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Magnetic resonance coupling is the near field wireless transmission of electrical energy between two coils that are tuned to resonate at the same frequency

Methodology Applied

Scientific EffectNear field communication: Electromagnetic Induction

Implementation Method 3

Methodology Applied

Scientific EffectTime multiplexing:

Data Source

PatentUS10673487B2Method, system and apparatus to optimize A4WP wireless charging and NFC co-existence

Publication Date: 2020.06.02 INTEL CORP

AI summary

The disclosure relates generally to method, system and apparatus to optimize wireless charging to identify a proximal Near-Field Communication (NFC) tag and prevent damage by a magnetic wireless charging field. The disclosed embodiment provide different methods for NFC tag detection without impacting A4WP wireless charging. In an exemplary method, dedicated NFC reader is used to interleave the NFC and A4WP signals on the same coil. In one implementation the signals are frequency-multiplexed. In another implementation, the signals are time-multiplexed.