LED Driver Random Sampling for Accurate Current Measurement
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Solution Overview
Problem
Current LED lighting devices lack compatibility with multiple power supplies and fail to mimic the characteristics of incandescent bulbs, leading to consumer dissatisfaction due to differences in light color temperature and behavior during dimming.
Innovation Solution
A solid-state lighting device that employs an array of LEDs, where a system controller samples the drive signal randomly or semi-randomly to determine a moving average, allowing for accurate measurement of voltage or current conditions, and adjusts the color temperature to mimic incandescent behavior during dimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LED lighting devices are designed specifically for a single power supply, then power supply compatibility is improved, but device versatility deteriorates
Solution Approach 1:
The lighting device incorporates a universal power supply interface that can accept multiple power supply types and configurations. The system includes adaptive detection circuitry that automatically identifies the connected power supply characteristics and adjusts operating parameters accordingly, enabling a single device design to work reliably across different power supply scenarios without requiring device-specific customization.
2Use of energy by moving object
If LED lighting devices maintain constant color temperature, then LED efficiency is improved, but consumer acceptance deteriorates
Solution Approach 1:
The lighting device implements dynamic color temperature adjustment capability that allows the color temperature to vary based on operational conditions such as dimming levels, ambient temperature, and user preferences. The control system monitors these parameters and automatically adjusts the LED drive characteristics to maintain optimal efficiency while providing natural-looking color temperature transitions that match consumer expectations from traditional lighting.
Solution Approach 2:
The system employs multiple LED channels with different color temperatures that can be independently controlled. By dynamically changing the intensity ratios of these channels, the device achieves variable color temperature output while maintaining overall lighting efficiency. This parameter adjustment capability allows the lighting to adapt to different ambient conditions and user preferences, bridging the gap between LED efficiency and consumer acceptance.
3Device complexity
If drive signal is measured using traditional sampling methods, then measurement simplicity is improved, but measurement precision deteriorates
Solution Approach 1:
The measurement system incorporates feedback mechanisms where the sampled drive signal is continuously monitored and compared against reference values. The sampling process includes multiple measurement points within each dimming cycle, and the results are fed back to adjust subsequent sampling parameters. This feedback loop compensates for synchronization errors and interference, progressively improving measurement precision while maintaining relatively simple hardware architecture.
Solution Approach 2:
The system uses periodic sampling synchronized to the dimming cycle frequency, with multiple samples taken at strategically selected phases within each period. By distributing samples across different phases and using moving average calculations, the system effectively filters out periodic interference and synchronization errors, achieving high measurement precision through structured periodic measurement patterns rather than complex real-time processing.
Data Source
AI summary
A lighting device employs at least one string of LEDs as a lighting source. The string of LEDs may be coupled in series between a power supply node and ground. In order to accurately determine a drive current running through or drive voltage across the string of LEDs, the drive current through the string of LEDs or the drive voltage across the string of LEDs is sampled randomly or semi-randomly, and a moving average is determined from each one of the samples. By sampling the drive current through or drive voltage across the string of LEDs randomly or semi-randomly, inaccuracies due to synchronization of the sampling with interference in the drive current signal or the drive voltage signal are effectively prevented. Accordingly, an accurate measurement of the drive current through or the drive voltage across the string of LEDs may be obtained.