Smart Card LED Control for Power-Saving Status Indication
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Solution Overview
Problem
Smart cards with light-emitting diodes (LEDs) for visual indication face power insufficiency issues due to high current consumption during high power operations, which can lead to processing inefficiencies and malfunctions.
Innovation Solution
A smart card design that includes a light-emitting element, a fingerprint sensor, and a microcontroller, where the microcontroller controls the current supplied to the light-emitting element by generating a light source control signal to decrease or stop current supply during power-saving periods, preventing power insufficiency by managing indication periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the LED is turned on to provide visual indication, then the user can see the operation status, but the smart card experiences power insufficiency during high current operations
Solution Approach 1:
The patent implements periodic action by controlling the LED to operate in indication periods with on-duty and off-duty sub-periods, rather than continuous operation. The microcontroller generates periodic indication signals that turn the LED on during on-duty sub-periods and off during off-duty sub-periods, allowing the system to balance visual indication needs with power consumption constraints during high current operations
Solution Approach 2:
The patent applies dynamics by making the LED control adaptive and variable based on real-time power conditions. The microcontroller dynamically adjusts the LED operation state according to power consumption levels of other components, transitioning between different operational modes (on during low power periods, off during high power periods) to optimize overall system power management
2Reliability
If the LED remains on continuously, then visual indication is always available, but the smart card may experience malfunction due to power insufficiency
Solution Approach 1:
The system uses periodic indication signals with defined on-duty and off-duty sub-periods to control LED operation. This periodic structure ensures the LED operates only during safe power windows, preventing continuous operation that would cause power insufficiency and system malfunction, thereby maintaining reliability while providing periodic visual feedback
Solution Approach 2:
The microcontroller implements feedback control by monitoring the power consumption state of the smart card system and adjusting LED operation accordingly. When power consumption exceeds safe thresholds during high current operations, the system feedbacks to turn off the LED, preventing power insufficiency conditions that would lead to system malfunction
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
The solution effectively manages power usage by temporarily turning off the LED during high current consumption periods, preventing power insufficiency and ensuring stable operation of the smart card while maintaining visual indication functionality.
Implementation Method 1
light-emitting elements are arranged on the smart card for visual indication. Normally, light-emitting diodes (LED) are used as the light-emitting elements
Data Source
AI summary
A smart card has a light-emitting element, a fingerprint sensor and a microcontroller. An operation of the smart card has a plurality of indication periods to indicate operation statuses of the smart card by the light-emitting element. The control method of the smart card includes generating a light source control signal, controlling a current supplied to the light-emitting element by the microcontroller according to the light source control signal, and decreasing the current supplied to the light-emitting element or stop the current supplied to the light-emitting element during at least one power-saying period in a first indication period of the plurality of indication periods.