Dimmable LED Fixture with Amber-White Current Regulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
LED light fixtures fail to simulate the warm glow effect of incandescent bulbs when dimmed, as they maintain constant color temperature, which is perceived as unnatural, and existing solutions with multiple-channel drivers are costly and complex.
Innovation Solution
A dimmable LED light fixture using a single-channel variable-DC LED driver with a current regulator to maintain constant current in an amber LED while reducing the white LED current, altering the combined light color, and optionally incorporating a microcontroller for precise control, allowing the use of off-the-shelf dimmable drivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple-channel LED drivers are used to control white and amber LEDs separately to achieve adjustable color temperature, then the color temperature adjustment capability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines white and amber LED light sources into a single optical system where both LEDs are driven by a single-channel variable-DC driver. The current regulator circuit merges the control functions by automatically adjusting the amber LED current based on the white LED current, eliminating the need for separate driver channels while achieving color temperature adjustment.
Solution Approach 2:
The current regulator is configured to automatically maintain a predetermined relationship between white and amber LED currents without external control signals. The regulator self-adjusts the amber LED current based on the white LED current level, enabling autonomous color temperature adjustment during dimming operations.
2Adaptability or versatility
If multiple-channel LED drivers are used to control white and amber LEDs separately, then the color temperature adjustment capability is improved, but the manufacturing cost increases
Solution Approach 1:
The patent combines white and amber LED light sources into a single optical system where both LEDs are driven by a single-channel variable-DC driver. The current regulator circuit merges the control functions by automatically adjusting the amber LED current based on the white LED current, eliminating the need for separate driver channels while achieving color temperature adjustment.
Solution Approach 2:
The single-channel variable-DC LED driver is designed to perform multiple functions: it drives both white and amber LEDs and works with standard AC dimmer modules. The current regulator adds universal compatibility by automatically adapting the amber LED current to match various dimming levels, making the system compatible with off-the-shelf drivers.
3Use of energy by moving object
If LED light fixtures use constant CCT white LEDs, then the energy efficiency is improved, but the ability to simulate incandescent warm glow effect deteriorates
Solution Approach 1:
The patent uses a composite light source system combining white LEDs (for energy efficiency) and amber LEDs (for color warmth). The optical system integrates both light sources to produce a composite spectrum that maintains LED energy efficiency while adding the warm spectral characteristics of incandescent light through the amber LED contribution.
Solution Approach 2:
The patent dynamically changes the color characteristics of the LED light output by varying the ratio of white to amber LED currents. During dimming, the current regulator increases amber LED current relative to white LED current, shifting the overall light color from cool white to warm amber-white, simulating the incandescent warm glow effect.
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
Achieves accurate simulation of incandescent lamp dimming characteristics with adjustable color temperature, reducing costs and complexity, and enabling retrofitting of existing LED fixtures without replacing them.
Implementation Method 1
a current regulator coupled in series with only the second LED light source, whereby the current in the second LED light source remains substantially constant as the LED driver DC output power is decreased
Implementation Method 2
first and second LED light sources, the first LED light source producing light visibly different in color from that of light produced by the second LED light source
Data Source
AI summary
Electronic circuitry for color-mixing in an LED light fixture during AC power dimming is disclosed to achieve adjustable color temperature. According to one embodiment, a dimmable LED light fixture has first, second, and third LED light sources, the first and second LED light sources producing white light, the third LED light source producing colored light, the LED driver configured to power the LED light sources by providing a single-channel variable-DC current source having two output terminals, and a current regulator for maintaining the current in the third LED light source path substantially constant as the LED driver output current is decreased when the AC power is reduced by the dimmer module, thereby altering the color of the light produced by the combination of the LED light sources.