Current Regulation Circuit for Contactless Card Stability

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Solution Overview

Problem

Existing remotely powered contactless cards experience errors due to variations in current consumption during data processing, which can be misinterpreted by the terminal as a response, leading to incorrect interpretations.

Innovation Solution

Incorporating a current regulation circuit that can be enabled or disabled by the processing module, using current mirrors and a current source to maintain a constant current during data processing phases, and an impedance regulation circuit to control power and voltage, ensuring stable current consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a current regulation circuit is kept continuously active to maintain constant current, then current stability is improved, but energy consumption increases

Engineering Contradiction:
Improvecurrent stabilityVSAvoidenergy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The current regulation circuit is designed to dynamically change its state based on operational requirements. It is activated during data processing phase P2 when current stability is needed, and deactivated during other phases when stability requirements are lower, allowing the system to adapt its regulation behavior to current operational needs

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The current regulation circuit operates periodically rather than continuously. It is enabled during specific phases (particularly phase P2 for data processing) and disabled during other phases, creating a periodic activation pattern that reduces overall energy consumption while maintaining current stability when actually needed

Inventive Principle:
Principle #19Periodic action

2Use of energy by moving object

If current varies during data processing, then energy optimization is improved, but signal accuracy deteriorates

Engineering Contradiction:
Improveenergy optimizationVSAvoidsignal accuracy
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The operational cycle is segmented into distinct phases (P0, P1, P2, P3) with different current stability requirements. The current regulation circuit is selectively applied to specific phases where it is most needed (particularly P2 for data processing), rather than being applied uniformly across all phases, thus optimizing both energy consumption and signal accuracy

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If the current regulation circuit is always active, then current constancy is improved, but operational efficiency deteriorates

Engineering Contradiction:
Improvecurrent constancyVSAvoidoperational efficiency
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The current regulation circuit is activated only during specific phases of the operational cycle, particularly during phase P2 when data processing occurs and current stability is critical. During other phases where current constancy is less critical, the regulation circuit is deactivated, thereby improving operational efficiency while maintaining current constancy when needed

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 solution stabilizes current consumption, preventing misinterpretation by the terminal and optimizing energy usage, thereby reducing errors and extending the operational distance between the card and terminal.

Implementation Method 1

The contactless card comprises an antenna (9) connected to a data processing module (11), via the intermediary of a rectifier (13). The terminal emits a field continuously. Thus, when the card is close to the terminal, it is powered by antenna (9)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The contactless card comprises an antenna (9) connected to a data processing module (11), via the intermediary of a rectifier (13)

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP3113331B1Remotely powered contactless card
Publication Date: 2021.04.21 STMICROELECTRONICS SA
  • EP3113331B1 patent drawingFigure 1A~1C
  • EP3113331B1 patent drawingFigure 2A~2B
  • EP3113331B1 patent drawingFigure 3

AI summary

The invention relates to a contactless card (100) configured to be powered by an antenna (9) connected to the input of a rectifier (13) whose output is coupled to a processing module (32) which can consume a first current (13), the contactless card comprising a current regulation circuit (34) also connected to the output of the rectifier (13), capable of absorbing a second current (11) such that the sum of the first and second currents is a constant current.