NFC Antenna Wireless Charging via Induced Current Detection

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Solution Overview

Problem

Current wireless charging systems for mobile devices require a separate charging receiver for each device, which is inconvenient for users with multiple mobile devices.

Innovation Solution

A method that utilizes a mobile device's existing NFC antenna to detect and redirect induced current above a threshold for an extended duration to a power management module for battery charging, eliminating the need for a dedicated charging receiver.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate charging receiver is used for each mobile device, then wireless charging can be achieved, but device complexity and accessory requirements increase

Engineering Contradiction:
Improvewireless charging capabilityVSAvoidcharging receiver requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The NFC antenna, originally designed solely for near field communication, is made multi-functional by enabling it to also serve as a wireless charging receiver. The antenna detects induced current from the charging station's electromagnetic field and redirects it to the power management module for battery charging, eliminating the need for a separate dedicated charging receiver.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the NFC communication function and wireless charging reception function into a single antenna system. The NFC antenna structure and circuitry are utilized dual-purpose: for both NFC data communication and for receiving wireless charging energy through electromagnetic induction, thereby reducing the number of separate components needed.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If an existing NFC antenna is used for charging, then device complexity is reduced, but current detection and threshold verification are required

Engineering Contradiction:
Improveantenna configurationVSAvoidcurrent threshold detection
Core Design Contradiction:
Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The power management module continuously monitors the current induced in the NFC antenna and compares it against a predetermined threshold. When the induced current exceeds the threshold for a specified duration, the system activates charging mode. This feedback mechanism ensures reliable detection of the charging station's electromagnetic field while preventing false activation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary verification by monitoring the induced current level and duration before initiating battery charging. This preliminary detection phase ensures that the NFC antenna is properly positioned near a charging station and that sufficient energy is available, preventing improper or insufficient charging.

Inventive Principle:
Principle #10Preliminary action

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 wireless battery charging without the need for a separate charging receiver, allowing multiple NFC-enabled devices to use a single charging station, improving convenience and reducing accessory requirements.

Implementation Method 1

NFC is a wireless technology that allows two devices to wirelessly communicate over a short distance of about 10 cm or less. NFC is standardized internationally within NFC Forum specifications and defined in, for example, ISO/IEC 18092, ISO/IEC 18000-3, ISO/IEC 21481, ECMA-340, ISO 14443, and the like, and any previous or subsequent versions. NFC technology is commonly used for contactless, short-range communications based on radio frequency identification (RFID) standards, using electromagnetic field induction to enable communication between electronic devices

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Charging receiver 104 then inductively receives energy via antenna 106 from an electromagnetic field generated by charging station 102

Methodology Applied
Scientific EffectElectromagnetic field generation: Electromagnetic Induction

Data Source

PatentEP2792043B1Method and apparatus for charging a battery in a mobile device through a near field communication (NFC) antenna
Publication Date: 2020.11.11 MARVELL ASIA PTE LTD
  • EP2792043B1 patent drawingFigure 1
  • EP2792043B1 patent drawingFigure 2
  • EP2792043B1 patent drawingFigure 3

AI summary

A near field communication (NFC) antenna in a mobile device is used to wirelessly charge a battery in the mobile device by placing the mobile device on, or in very close proximity to, a charging station that emits an electromagnetic field. An induced current from the NFC antenna is detected that is above a predetermined threshold for longer than a predetermined duration. The induced current is used to charge the battery in the mobile device.