Microcircuit Card LED Control Using Dual-Voltage Phases

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Solution Overview

Problem

Current microcircuit cards, particularly those equipped with biometric sensors, lack the ability to effectively display information to users, limiting their functionality and user interaction.

Innovation Solution

Incorporating a light-emitting diode (LED) control mechanism using two voltage phases, where a first circuit provides a supply voltage at a lower value to power the microcontroller and biometric sensor during communication phases, and a second circuit applies a higher voltage to the LED to control its emission, allowing the LED to provide information to the user during specific phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a light-emitting diode is added to provide visual feedback, then the card can display information to the user, but the device complexity increases

Engineering Contradiction:
Improveinformation display capabilityVSAvoidcircuit complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent combines the LED control function with the existing communication conductor between the first and second circuits. The same conductor that carries communication signals during the first phase is reused to control the LED during the second phase, eliminating the need for separate LED control wiring and reducing overall device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The conductor serving the second circuit is given multiple functions: it serves as a communication channel during the first operating phase and as an LED control line during the second operating phase. This multi-functionality reduces the total number of components and simplifies the device structure

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

2Loss of information

If the LED is controlled during communication phases, then visual feedback can be provided, but it may cause interference with communication signals

Engineering Contradiction:
Improvevisual feedback capabilityVSAvoidcommunication reliability
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The patent implements periodic switching between two distinct operating phases: a first phase dedicated to communication where the LED remains off, and a second phase dedicated to LED control where visual feedback is provided. This time-division approach ensures that communication and LED control operations do not interfere with each other

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

Before enabling LED control, the system first completes the communication phase entirely. The transition to the second phase occurs only after communication is finished, ensuring that no interference occurs between communication signals and LED control signals

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If a single supply voltage is used for all circuits, then the power supply design is simplified, but the LED cannot be controlled to emit light selectively

Engineering Contradiction:
Improvepower supply designVSAvoidLED control capability
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent employs dynamic voltage adjustment where the supply voltage to the second circuit is changed based on the operating phase. During the first phase, a first voltage value is applied, and during the second phase, a second voltage value is applied to enable LED control. This dynamic approach allows simple power supply design while maintaining full LED control capability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the voltage parameter of the supply based on the operating phase. By adjusting the voltage level dynamically, the system achieves selective LED control without requiring complex power supply circuits, maintaining design simplicity while enabling operational flexibility

Inventive Principle:
Principle #35Parameter changes

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 the microcircuit card to provide visual feedback to the user, such as indicating fingerprint recognition or enrollment processes, while maintaining efficient energy consumption and preventing light emission during communication phases.

Implementation Method 1

a light-emitting diode having a first terminal connected to the conductor and a second terminal connected to a first terminal of the second circuit

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Data Source

PatentEP4002211B1Microcircuit board
Publication Date: 2023.09.13 STMICROELECTRONICS (ROUSSET) SAS
  • EP4002211B1 patent drawingFigure 1~2
  • EP4002211B1 patent drawingFigure 3
  • EP4002211B1 patent drawingFigure 4~5

AI summary

This description relates to a microcircuit board (1) comprising: a first circuit (100) supplying a supply voltage (Vdd); a second circuit (108) connected to the first circuit (100) by an electrical conductor (110) and supplied by the supply voltage (Vdd); and a light-emitting diode (116) having a first terminal connected to the conductor (110) and a second terminal connected to a first terminal (118) of the second circuit (108), in which, during a first phase of operation, the first circuit (100) supplies a first value of the supply voltage (Vdd) and the second circuit (108) applies a first voltage on the first terminal (118), and, during a second phase of operation, the first circuit (100) supplies a second value of the supply voltage (Vdd) and the second circuit (108) applies a second voltage on the first terminal (118).