Wireless Charging Control Using NFC Modulation Detection

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Solution Overview

Problem

Existing wireless charging devices lack the capability to differentiate between passive and active NFC devices, which can lead to potential damage to passive devices due to excessive power transfer.

Innovation Solution

A wireless charging device equipped with a detection unit that analyzes the modulation characteristic of an NFC signal to distinguish between passive and active NFC devices, with a controller that adjusts the charging process accordingly to prevent damage to passive devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the charging unit transfers power to all detected NFC devices, then active NFC devices can be charged efficiently, but passive NFC devices may receive excessive power and be damaged

Engineering Contradiction:

Improvecharging efficiencyVSAvoidexcessive power to passive devices

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary detection of the NFC device type before initiating the charging process. The detection unit analyzes the modulation characteristic of the NFC signal to identify whether the external device is passive or active, and the controller pre-determines the appropriate charging strategy based on this detection, preventing excessive power transfer to passive devices before damage can occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the modulation characteristic of the NFC signal during the charging process. Based on the feedback from the detection unit about the device type, the controller dynamically adjusts the power transfer level, maintaining safe operation for passive devices while enabling efficient charging for active devices.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If the charging unit prevents charging for all detected NFC devices, then passive NFC devices are protected from damage, but active NFC devices cannot be charged

Engineering Contradiction:

Improveprotection from excessive powerVSAvoidcharging capability

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system applies different charging characteristics to different types of NFC devices. Passive NFC devices receive protective treatment with limited or no power transfer, while active NFC devices receive full charging power. This local differentiation based on device type allows simultaneous protection of vulnerable devices and efficient charging of chargeable devices.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The controller changes the power transfer parameter based on the detected NFC device type. When a passive device is detected, the power transfer parameter is set to zero or a protective level. When an active device is detected, the power transfer parameter is adjusted to enable efficient charging, thus adapting the charging behavior to the specific device characteristics.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If the wireless charging device does not differentiate between passive and active NFC devices, then the device complexity is reduced, but the reliability of the charging process deteriorates due to potential device damage

Engineering Contradiction:

Improvedetection and control mechanismVSAvoidsafe charging operation

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system replaces complex mechanical or hardware-based device identification mechanisms with signal analysis of the existing NFC communication. By analyzing the modulation characteristic of the NFC signal that is already being exchanged for communication purposes, the system identifies device type without requiring additional sensors, physical switches, or complex identification hardware.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 prevents damage to passive NFC devices by ensuring that they do not receive excessive power, while allowing active devices to be charged efficiently.

Implementation Method 1

a charging unit configured to charge an external device by wirelessly transferring power to the external device

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a detection unit configured to detect whether the external device is a passive near field communication (NFC) device or an active NFC device by analyzing a modulation characteristic of an NFC signal

Methodology Applied

Scientific EffectNear field communication electromagnetic field generation: Electromagnetic Induction

Data Source

PatentUS20250023395A1Wireless charging device and operating method

Publication Date: 2025.01.16 NXP BV

AI summary

In accordance with a first aspect of the present disclosure, a wireless charging device is provided, comprising: a charging unit configured to charge an external device by wirelessly transferring power to said external device; a detection unit configured to detect whether the external device is a passive near field communication (NFC) device or an active NFC device by analyzing a modulation characteristic of an NFC signal received by the external device; a controller configured to control the charging unit in dependence on an output of the detection unit, wherein said output indicates whether the external device is a passive NFC device or an active NFC device. In accordance with a second aspect of the present disclosure, a corresponding method of operating a wireless charging device is conceived.