LED Fixture Circuit Maintains Brightness During Color Temperature Shift
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Solution Overview
Problem
Existing dimmable LED light fixtures struggle to maintain brightness while changing color temperature, unlike traditional incandescent lamps, which can lead to disruptive light environments and health issues due to inconsistent light exposure.
Innovation Solution
A dimmable LED light fixture with two LED light sources of different Kelvin temperatures (5000K and 2000K) and control circuitry that adjusts the drive current proportionally with a dimmer switch, using a composite signal processing circuit to maintain brightness while changing color temperature across the dimmer switch range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LED light sources are used to achieve energy efficiency and long life, then energy consumption is reduced and lifespan is extended, but color temperature remains constant and does not change with brightness adjustment
Solution Approach 1:
The LED light source is divided into multiple LED chips with different color temperatures (e.g., 3000K and 2000K chips). Each chip type contributes differently to the overall light output, allowing independent control of color temperature characteristics while maintaining energy efficiency benefits of LED technology.
Solution Approach 2:
The patent changes the electrical parameters (current ratio) supplied to different LED chip types to achieve variable color temperature. By adjusting the current distribution among chips with different color temperatures, the system can dynamically change the overall color temperature output while maintaining brightness, resolving the contradiction between energy efficiency and color temperature adaptability.
2Adaptability or versatility
If multiple LED chips with different color temperatures are used to achieve variable color temperature, then color temperature adaptability is improved, but device complexity increases due to additional circuitry for current ratio control
Solution Approach 1:
The control circuitry is designed to perform multiple functions simultaneously: it controls both the brightness level and the color temperature by adjusting current ratios to different LED chip types. This multi-functionality reduces the need for separate control systems, thereby managing complexity while achieving color temperature variability.
Solution Approach 2:
The system dynamically adjusts the current ratio supplied to different LED chip types based on the desired color temperature and brightness level. This dynamic control allows the circuitry to adapt to different operating conditions, achieving color temperature variability without requiring overly complex static control mechanisms.
3Illumination intensity
If brightness is reduced in LED light sources, then energy consumption decreases, but color temperature remains unchanged and may create disruptive light environments
Solution Approach 1:
The patent changes the color temperature parameter independently of brightness by adjusting the current ratio to different LED chip types. When brightness is reduced, the system can simultaneously adjust the color temperature to warmer tones (lower Kelvin values), preventing the harmful effects of bright blue-rich light during nighttime while maintaining appropriate illumination levels.
Solution Approach 2:
The system incorporates control circuitry that can respond to ambient conditions and usage patterns to automatically adjust both brightness and color temperature. This feedback mechanism ensures that the light output is optimized for health considerations, reducing blue light exposure during nighttime hours while maintaining visual comfort.
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 solution allows for a consistent bright light environment with adjustable color temperature, reducing the risk of light disruption and promoting healthier lighting conditions by maintaining brightness while changing color temperature from 5000K to 2000K, creating a warm and relaxing ambiance.
Implementation Method 1
The fixture incorporates a first LED light source producing white or warm light and a second LED light source producing light of a visibly different color
Data Source
AI summary
An LED light fixture, in the form of lamps or luminaires, is comprised on a plurality of LED lights producing bright white or warm light and a plurality of color LED lights producing light of a visibly different color. The fixture includes control circuitry for receiving an input voltage signal from a dimmer switch wherein when the dimmer switch reduces the input voltage to the LED light fixture within a top range setting of the dimmer switch, the brightness of the light is maintained while the color Kelvin temperature of the light spectrum is reduced. If the dimmer switch is increased in the top range, the color temperature increases. This is achieved by increasing the frequency of a reduced input voltage signal during a reduction of the dimmer switch in the top range thereof to supply full driver current to the white or warm light LED's while reducing the driver current to the color LED's. When the dimmer switch is operated below the top range both drive currents to the while and color LED's is reduced to provide a warm relaxing light spectrum but with substantially high luminosity/brightness.