Aerospace LED Life Monitor Using Current and Temperature Compensation
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Solution Overview
Problem
Existing LED-based lighting systems lack the ability to monitor key operational parameters, such as current and temperature, which are crucial for predicting the remaining life and detecting failure conditions, especially in flight-critical applications where unpredicted malfunctions can occur due to degradation or failure.
Innovation Solution
A system that monitors the operational life and performance of LEDs by recording the time in operation, measuring current and temperature, and using these parameters to compensate for clock signal frequency, allowing for real-time monitoring and testing for failure conditions, including short and open circuit conditions, even when the LEDs are turned off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive, open-loop control systems are used for LED-based lights, then device complexity is reduced, but reliability deteriorates due to inability to monitor key operational parameters
Solution Approach 1:
The patent implements feedback mechanisms by continuously monitoring LED operational parameters (current, temperature, voltage) and using this information to adjust control decisions. The system measures key parameters during operation and feeds this data back to the control logic, enabling closed-loop control that improves reliability while managing complexity through targeted parameter monitoring rather than comprehensive system monitoring.
Solution Approach 2:
The system performs self-diagnosis and self-monitoring by using the LED's own operational characteristics (current-voltage relationships, temperature responses) to assess its health status. The monitoring system leverages existing operational data without requiring separate diagnostic test equipment, allowing the LED system to self-evaluate its operational condition during normal operation.
2Reliability
If key LED parameters are monitored in real-time, then reliability improves through prediction of remaining operational life, but device complexity increases due to additional sensing and processing requirements
Solution Approach 1:
The monitoring system is designed to serve multiple functions simultaneously: it monitors current for both operational control and life prediction, measures temperature for both thermal management and reliability assessment, and collects voltage data for both efficiency optimization and failure prediction. This multi-functionality reduces overall system complexity by consolidating monitoring capabilities into a unified system that extracts multiple benefits from the same sensor infrastructure.
Solution Approach 2:
The system tracks changes in key operational parameters (current, voltage, temperature) over time and uses these parameter trends to predict remaining operational life. By monitoring how parameters evolve during operation rather than relying on fixed thresholds, the system can estimate LED degradation and predict failures before they occur, improving reliability without requiring complex predictive models.
3Reliability
If testing for failure conditions is performed only when LEDs are turned on, then ease of operation is maintained, but reliability deteriorates due to inability to detect open circuit conditions when LEDs are off
Solution Approach 1:
The system performs preliminary testing of LED circuits by applying test signals during periods when the LEDs are not actively emitting light. The monitoring system can detect open circuit and short circuit conditions by measuring electrical characteristics during these idle periods, before actual failure occurs during operation. This preliminary detection capability ensures reliability without interfering with normal operational simplicity.
Solution Approach 2:
The system implements periodic testing cycles where failure condition detection is performed at regular intervals during LED off-periods. Rather than continuously monitoring during operation (which would complicate the system), the monitoring system periodically inserts test measurements during natural idle periods, maintaining ease of operation while ensuring reliability through regular assessment of circuit integrity.
Data Source
AI summary
A system (10) and method for monitoring the operational life and/or performance of one or more light-emitting diodes (LEDs) (20) based on sensed parameters are disclosed. The remaining life of each LED may be predicted by counting the clock cycles during which the LED-based light is activated. LED current and/or temperature measurements may be used to control the clock signal and, thus, to compensate the predicted life value. Furthermore, operational characteristics of the LED-based light may be monitored based on LED current and/or voltage measurements. Such characteristics may include performance (e.g., intensity) and failure conditions (e.g., open or short circuits).