Multi-Channel LED Driver Control for Natural Dimming Color Shift

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Solution Overview

Problem

Discrete-spectrum light sources like LEDs and CFLs do not follow Plank's law when dimmed, resulting in unnatural color temperature changes that can appear distracting or unnatural to the human eye, especially when placed near traditional black body radiator light sources.

Innovation Solution

A lighting control system that uses multiple LED drivers to adjust the intensity of LED light sources based on a single digital message, allowing for precise control of color temperature by varying the intensity of discrete-spectrum light sources to mimic the behavior of traditional black body radiators, ensuring consistent and natural color shifts during dimming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If discrete-spectrum light sources (LEDs/CFLs) are dimmed, then energy consumption is reduced, but color temperature changes become unnatural and distracting

Engineering Contradiction:
Improveenergy consumptionVSAvoidunnatural color temperature changes
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the color temperature of discrete-spectrum light sources to match the color temperature trajectory of black body radiators during dimming. Instead of maintaining fixed color temperatures, the system varies multiple parameters (intensity of different wavelength LEDs, color temperature) to simulate natural incandescent behavior, thereby reducing the harmful effect of unnatural color shifts while maintaining energy efficiency.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple LED drivers are used to control color temperature, then color temperature control precision is improved, but device complexity increases

Engineering Contradiction:
Improvecolor temperature control precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the lighting control into multiple independent channels, each controlled by a separate LED driver. Each driver manages specific wavelength LEDs (e.g., red, green, blue channels) independently, allowing precise control of color temperature through coordinated adjustment of multiple segments. This segmentation enables fine-grained color temperature control while maintaining modular device architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies universality by designing LED drivers that can simultaneously perform multiple functions: controlling intensity, adjusting color temperature, and simulating dimming behavior. The drivers are configured to work together as an integrated system that can produce various color temperatures and dimming curves, reducing the need for separate dedicated control devices and minimizing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If discrete-spectrum light sources mimic black body radiator behavior, then visual naturalness is improved, but control system complexity increases

Engineering Contradiction:
Improvevisual naturalnessVSAvoidcontrol system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies copying by replicating the dimming behavior characteristics of black body radiators using discrete-spectrum LED sources. The control system is programmed with predefined dimming curves and color temperature trajectories that mirror traditional incandescent lamp behavior. By copying the temporal and spectral characteristics of natural light sources, the system achieves visual naturalness without requiring complex real-time calculations, instead using predetermined patterns that simplify control.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3235345B1Multi-channel lighting fixture having multiple light-emitting diode drivers
Publication Date: 2024.03.06 LUTRON TECHNOLOGY COMPANY LLC
  • EP3235345B1 patent drawingFigure 1
  • EP3235345B1 patent drawingFigure 2
  • EP3235345B1 patent drawingFigure 3

AI summary

A lighting control system (300) for controlling a cumulative light emitted by a lighting fixture (310, 320, 330) having a plurality of LED light sources (312, 322A-B, 332A-C)) may comprise a plurality of LED drivers (314, 324A-B, 334A-C) adapted to be coupled to a respective one of the LED light sources and configured to control an intensity of the respective LED light source, and a controller (340) configured to transmit a single digital message (305) for controlling the cumulative light emitted by the lighting fixture. Each of the plurality of LED drivers is configured to adjust the intensity of the respective LED light source to a preset intensity in response to the single digital message transmitted by the controller (340).