LED Driver Multi-Mode Color Control With Reduced Flicker
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Solution Overview
Problem
Conventional LED-based illumination systems face challenges in efficiently determining how to generate a desired color point with multiple LEDs, leading to higher complexity and cost, and issues with power consumption and flicker.
Innovation Solution
A method for controlling a plurality of LEDs by receiving a set point representing desired color and intensity, determining subsets of LEDs with corresponding intensity set points, and selecting subsets that meet predetermined criteria such as CRI, efficiency, and flicker reduction, using a control unit to adjust current and duty cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If more than three LEDs or LED groups are used to generate a wider color gamut, then color rendering capability is improved, but device complexity increases and calculation becomes indeterminate
Solution Approach 1:
The patent segments the control problem by dividing the set of four or more LEDs into different subsets (first subset and second subset). Each subset is controlled independently with its own intensity set points, transforming an indeterminate system-level problem into two determinate subset-level problems that can be solved separately and then combined.
Solution Approach 2:
The patent introduces intensity set points as intermediary variables that mediate between the desired color point and the actual LED outputs. By calculating intensity set points for each subset based on color characteristics, the system creates a intermediate representation that simplifies the control of multiple LEDs to achieve the target color.
2Loss of energy
If conventional methods are used to control multiple LEDs, then power consumption increases, but control efficiency remains low
Solution Approach 1:
The patent changes the control parameters by using intensity set points that are specifically calculated to optimize both power consumption and control efficiency. By adjusting the intensity parameters of individual LEDs within subsets based on their color characteristics and the desired color point, the system achieves energy-efficient control without sacrificing productivity.
3Measurement precision
If multiple subsets of LEDs are controlled independently, then color precision is improved, but flicker may occur
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual color output and comparing it with the desired color point. Based on this feedback, the intensity set points for each subset are adjusted to maintain color precision while coordinating the operation of multiple LED subsets to minimize flicker effects.
Solution Approach 2:
The patent uses periodic action by implementing coordinated switching and dimming cycles for different LED subsets. By synchronizing the operation of subsets and using periodic intensity adjustments, the system maintains precise color control while reducing visible flicker through rhythmic, coordinated operation.
Data Source
AI summary
Method of controlling an LED fixture comprising a plurality of LEDs, the plurality of LED comprising at least four LEDs, configured to emit light of different colors, the method comprising:receiving a set point representing a desired color and intensity for the light to be generated by the LED fixture;determining, based on available color characteristics of the plurality of LEDs, at least two different subsets of the plurality of LEDs and a set of intensity set points for each of the at least two different subsets, wherein each set of intensity set points results in obtaining or approximating the desired color and intensity by the LED fixture;selecting the subsets of the plurality of LEDs with the corresponding sets of intensity set points which meet a predetermined criterion;use a selected subset to drive the plurality of LEDs with the corresponding set of intensity set points.