Multi-Color LED Dimming Algorithm for Color Consistency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dimming methods for LED lighting systems, such as PWM Dimming, suffer from flicker issues and inefficiency, while Analog Dimming leads to undesirable color variation due to changing current density, which is not effectively corrected by current technologies.
Innovation Solution
A multi-color lighting system that employs a two-pass compensation process to determine driver settings, adjusting initial and color-corrected driver settings to maintain desired color characteristics when dimming, using a microcontroller to control LED driver circuits and account for temperature changes and lifetime degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If PWM Dimming is used to dim LED light output, then light intensity can be controlled, but flicker occurs and efficiency decreases
Solution Approach 1:
The patent applies periodic action through PWM dimming by turning LEDs ON and OFF at fixed frequencies higher than human visual perception threshold. This creates the appearance of continuous light while controlling average intensity through duty cycle variation, thereby eliminating visible flicker while maintaining intensity control.
2Illumination intensity
If PWM Dimming is used to dim LED light output, then light intensity can be controlled, but energy efficiency decreases
Solution Approach 1:
The patent achieves energy efficiency improvement by using PWM dimming at optimized frequencies and duty cycles. By controlling LEDs to operate at full intensity during ON periods and completely OFF during OFF periods, the system avoids the inefficiencies of analog dimming where LEDs operate at reduced current levels, thereby improving overall energy efficiency while maintaining intensity control capability.
3Use of energy by moving object
If Analog Dimming is used to dim LED light output, then energy efficiency improves, but color variation occurs
Solution Approach 1:
The patent applies parameter changes by systematically varying current levels across multiple dimming steps and measuring corresponding color coordinates. This data is used to build correction algorithms that compensate for color shifts, thereby maintaining color consistency while utilizing the energy efficiency benefits of analog dimming.
Solution Approach 2:
The patent implements feedback mechanisms by measuring actual color coordinates at different current levels and using this information to adjust driver settings. The system continuously monitors and corrects color deviations, ensuring color consistency is maintained throughout the dimming range while benefiting from analog dimming efficiency.
4Adaptability or versatility
If multi-color LEDs are used in a lighting system, then color versatility improves, but flicker becomes more pronounced
Solution Approach 1:
The patent applies universality by implementing a unified control algorithm that simultaneously manages multiple color channels (Red, Green, Blue LEDs) with consistent PWM parameters. This ensures all color sources operate at the same frequency and phase relationships, maintaining color versatility while preventing differential flicker that would arise from independent channel control.
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 system produces a color-corrected output light with consistent color characteristics and reduced flicker, improving efficiency and maintaining desired intensity levels even under temperature and degradation changes.
Implementation Method 1
An LED produces light output, when a voltage across two terminals thereof (e.g., anode and cathode) exceeds the LED's forward voltage so that forward current can flow through the LED
Data Source
AI summary
A lighting system having at least three light sources receives an input relating to color coordinates of a target point representing a desired color characteristic for a combined output from the light sources. The system defines first-pass endpoints corresponding to color characteristics of the light sources when operated at respective maximum intensities. The system determines first-pass amounts of respective maximum intensity contributions from the light sources to achieve light of the target point. When dimming the light to an intensity proportion, the system determines first-pass driver settings from the first-pass amounts and the intensity proportion. The system defines second-pass endpoints corresponding to color characteristics of the light sources when operated at the determined first-pass driver settings. The system determines, from the second-pass endpoints, second-pass amounts of respective reduced intensity contributions from the light sources; and the system determines second-pass driver settings for the second-pass amounts.