LED Lighting Apparatus Detector Current Monitoring
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Solution Overview
Problem
Existing LED lighting systems in passenger aircraft require time-consuming and unreliable visual checks to determine the functionality of LED modules, which is inefficient and not always accurate.
Innovation Solution
An LED lighting apparatus with a control module that generates a PWM signal using a push-pull circuit and includes a measuring circuit to detect a predefined detector current during switched-off times, allowing for the determination of the functional state of the LED lighting module through the measurement of instantaneous current levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If visual checks are used to check LED functionality, then no additional measuring circuit is needed, but the checking process is time-consuming and unreliable
Solution Approach 1:
The LED lighting module performs self-diagnosis by incorporating a measuring circuit that automatically detects the functional state of LEDs through detector current measurement, eliminating the need for manual visual inspection by operators
Solution Approach 2:
The measuring circuit provides continuous feedback about the LED functional state by measuring detector current levels and comparing them against reference values, enabling automatic detection of defective LEDs without manual intervention
2Reliability
If a measuring circuit is added to monitor LED functionality, then functionality check reliability improves, but the device complexity increases
Solution Approach 1:
The measuring circuit is integrated into the existing control module, and the detector current path is merged with the existing signal transmission path between the control module and LED lighting module, eliminating the need for separate monitoring hardware
Solution Approach 2:
The signal transmission path serves dual purposes: transmitting PWM control signals to the LED lighting module and carrying detector current back to the measuring circuit for functionality monitoring
3Illumination intensity
If the PWM signal duty cycle is set to 100%, then the LED brightness is maximized, but the measuring circuit cannot measure detector current during switched-off times
Solution Approach 1:
The PWM signal uses periodic switching with a duty cycle of less than 100%, creating regular switched-off intervals that allow the measuring circuit to periodically sample detector current while maintaining sufficient average LED brightness through high-duty-cycle operation
Data Source
AI summary
The invention relates to an LED lighting apparatus comprisinga control module having a push-pull circuit for generating a pulse-width-modulated (PWM) signal,an LED lighting module which is connected to the control module via a signal transmission path, which is intended to transmit the PWM signal to a signal converter accommodated in the LED lighting module, and to a current source, the brightness of at least one LED being controlled using the signal converter on the basis of the PWM signal received thereby, the LED lighting module also containing a device for generating a detector current having a predefined level, anda measuring circuit for measuring the instantaneous level of the detector current being connected in the control module in such a manner that, during the switched-off times of the PWM signal, the measuring circuit is connected to the LED lighting module via the signal transmission path such that the instantaneous level of the detector current can be measured using the measuring circuit and a functional state of the LED lighting module can be determined therefrom.