Inductive Energy Transfer Touch Sensing Interference

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Solution Overview

Problem

Inductive energy transfer systems face inefficiencies due to power losses and interference with touch sensing devices during energy transfer, limiting device portability and safety, as well as potential hazards from charging cords.

Innovation Solution

A method where the inductive energy transfer system periodically turns off energy transfer to allow touch sensing devices to function by having the receiver device signal the transmitter to turn off for specific periods, enabling touch sampling while energy is not being transferred.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If inductive energy transfer is performed continuously, then energy transfer efficiency is improved, but touch sensing device performance deteriorates due to noise interference

Engineering Contradiction:
Improvepower lossVSAvoidtouch sensing device performance
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system implements periodic interruption of inductive energy transfer at predetermined time intervals. During these interruption periods, the transmitter device stops transferring energy, allowing the touch sensing device to operate without electromagnetic interference. This periodic action resolves the contradiction by alternating between energy transfer mode and touch sensing mode, ensuring both functions can operate effectively.

Inventive Principle:
Principle #19Periodic action

2Productivity

If inductive energy transfer is performed continuously, then charging speed is improved, but device portability is reduced due to safety hazards from charging cords

Engineering Contradiction:
Improvecharging speedVSAvoiddevice portability
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The system replaces the mechanical charging cord connection with wireless inductive energy transfer. The transmitter device wirelessly transmits energy to the receiver device through electromagnetic fields, eliminating the need for physical plugging and unplugging of charging cords. This substitution maintains charging speed while significantly improving device portability and safety by removing the mechanical connection hazard.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of energy

If inductive energy transfer is performed continuously, then energy transfer efficiency is improved, but noise interference to touch sensing device increases

Engineering Contradiction:
Improvepower lossVSAvoidnoise interference
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The system periodically interrupts energy transfer to create noise-free windows for touch sensing operation. By stopping energy transfer at predetermined intervals, the electromagnetic noise generated during inductive coupling is eliminated, allowing the touch sensing device to detect touches accurately. This periodic interruption directly addresses the harmful noise interference while maintaining overall energy transfer efficiency.

Inventive Principle:
Principle #19Periodic 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

This approach enhances the efficiency of inductive energy transfer by reducing power losses and minimizes interference with touch sensing devices, improving device portability and safety by allowing touch detection during energy transfer.

Implementation Method 1

The charging device transfers energy to the electronic device through inductively coupling between a transmitter coil in the charging device and a receiver coil in the electronic device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2993760B1Operating an inductive energy transfer system
Publication Date: 2018.06.06 APPLE INC
  • EP2993760B1 patent drawingFigure 1~2
  • EP2993760B1 patent drawingFigure 3
  • EP2993760B1 patent drawingFigure 4

AI summary

A receiver device in an inductive energy transfer system can include a touch sensing device. If the input surface of the touch sensing device is touched, a transmitter device can periodically stop transferring energy to allow the touch sensing device to sense touch samples while inductive energy transfer is inactive. Additionally or alternatively, a transmitter device can produce an averaged duty cycle by transferring energy to the receiver device for one or more periods at a first duty cycle step and for one or more periods at different second first duty cycle step. Additionally or alternatively, a transmitter device can reduce a current level received by a DC-to-AC converter if the current received by the DC-to-AC converter equals or exceeds a threshold. Additionally or alternatively, a transmitter device can ping a receiver device and transfer energy only after a response signal is received from the receiver device.