RF-Triggered NFC Power Switching Without a Power Button

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Solution Overview

Problem

Existing NFC devices require a power button for activation, which can be inconvenient and may lead to accidental power-off, and passive NFC tags lack a mechanism to maintain power without continuous RF signal reception.

Innovation Solution

An NFC device design that uses a passive NFC tag circuit to connect a battery voltage output terminal to an internal system voltage input terminal in response to a system power-on command from an external NFC device, maintaining the connection without additional RF signal input, using a switch circuit and microcontroller unit to manage power states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a power button is included in the NFC device, then the device can be manually activated and deactivated, but the device becomes more complex and prone to accidental power-off

Engineering Contradiction:

Improvemanual power controlVSAvoidpower button structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent removes the power button from the NFC device structure entirely, extracting the manual power control function and replacing it with automatic RF-triggered power activation. This eliminates the physical component while maintaining power control capability through a different mechanism.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The NFC device automatically activates power when it detects an RF signal from an external NFC device, eliminating the need for manual user intervention. The system serves itself by autonomously determining when power should be activated based on the presence of communication signals.

Inventive Principle:

Principle #25Self-service

2Reliability

If the NFC device maintains power continuously, then the internal system remains ready for operation, but energy is consumed unnecessarily when not in use

Engineering Contradiction:

Improvesystem readinessVSAvoidbattery consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

Instead of continuous power maintenance, the system uses periodic activation triggered by RF signal detection. The power system transitions between off and on states based on the periodic presence of NFC communication signals, optimizing energy usage while maintaining operational readiness when needed.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The power state of the NFC device becomes dynamic rather than static, automatically transitioning between powered-off and powered-on states based on external RF signal conditions. This dynamic behavior allows the system to adapt its power consumption to actual operational needs.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If the NFC device uses passive NFC tag circuit without battery, then the device structure is simplified, but the device cannot maintain power without continuous RF signal reception

Engineering Contradiction:

Improvepower supply structureVSAvoidpower maintenance duration

Core Design Contradiction:

Device complexityVSDuration of action of stationary object

Solution Approach 1:

The patent merges the advantages of both active and passive NFC approaches by combining a battery with a passive tag circuit. The battery provides long-term power storage while the passive tag circuit enables RF-triggered activation, creating a hybrid system that leverages both energy storage and signal-responsive operation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The battery is pre-charged and ready to provide power before RF signal reception occurs. When an RF signal is detected, the pre-prepared battery power is immediately activated to sustain the internal system, eliminating the need for continuous RF signaling while maintaining operational capability.

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 continuous operation of the NFC device without a power button, ensuring power is maintained until the battery lifespan ends, facilitating convenient and reliable NFC communication.

Implementation Method 1

The passive RFID tag generates operating voltages necessary for the passive RFID tag by using an RF signal transmitted by an RFID reader

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS12457011B2NFC device powered on in response to radio frequency signal, NFC tag circuit included therein, and method of operating the NFC device

Publication Date: 2025.10.28 3A LOGICS CO LTD

AI summary

Disclosed is an NFC device not having a power button. The NFC device includes a battery including a voltage output terminal from which a battery voltage is output, an internal system including a voltage input terminal and using the battery voltage as an operating voltage, and an NFC tag circuit configured to connect the voltage output terminal of the battery and the voltage input terminal of the internal system in response to only a system power-on command included in a system power-on NFC signal that is transmitted by an external NFC device and to maintain the connection between the voltage output terminal of the battery and the voltage input terminal of the internal system in response to the battery voltage.