Dimmable LED Fixture for Concurrent CCT and Brightness Control
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Solution Overview
Problem
Conventional LED dimming circuits struggle to simultaneously adjust brightness and color temperature (CCT) due to standard dimmers modifying current through LED drivers, leading to difficulties in maintaining color temperature output while allowing for brightness adjustment.
Innovation Solution
A dimmable LED light fixture with integrated control circuitry that utilizes a dimmer switch and a CCT controller to independently adjust brightness and color temperature, allowing for smooth transitions between different CCT settings and maintaining user-defined setpoints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If standard dimming circuits are used to adjust brightness, then brightness control is achieved, but color temperature cannot be adjusted concurrently
Solution Approach 1:
The LED light fixture is divided into multiple LED modules, each emitting different color temperatures (e.g., warm white, cool white). This segmentation allows independent control of each module's brightness through separate PWM signals, enabling concurrent adjustment of overall brightness and color temperature by mixing different proportions of colored LED outputs.
2Illumination intensity
If LED driver current is modified for dimming, then brightness adjustment is achieved, but color temperature remains unchanged
Solution Approach 1:
Different LED modules are assigned different color temperature characteristics (local quality). By independently controlling the drive current to each module with separate PWM dimming circuits, the system can adjust the brightness contribution of each color temperature component locally, thereby achieving overall brightness control while simultaneously adjusting the mixed color temperature output.
3Adaptability or versatility
If multiple LED color temperatures are mixed, then color temperature control is improved, but system complexity increases
Solution Approach 1:
Multiple LED modules with different color temperatures are combined in a single light fixture, and their control circuits are merged into a unified system. The control circuit receives a single control signal and generates appropriate PWM signals for each LED module, coordinating their brightness ratios to achieve the desired color temperature while simplifying the overall control architecture.
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
Enables concurrent control of brightness and CCT, providing a warm and cozy lighting environment by maintaining or adjusting these parameters based on dimmer switch and CCT controller positions, mimicking the color changes of incandescent lamps.
Implementation Method 1
The LED lamp includes a bank of LEDs emitting light during operation to produce composite light having a brightness and a composite CCT
Implementation Method 2
LED light sources do not exhibit visible spectrum radiation at all wave lengths of the spectrum and are measured according to a correlated color temperature (CCT) scale
Data Source
AI summary
Components and circuitry for controlling a bank of LEDs based on a dimmer switch and a CCT controller to maintain a brightness level while changing the color temperature of an emitted composite light, to adjust a brightness level simultaneous to changing the color temperature of the emitted composite light, and to drive the bank of LEDs to generate the composite light based on selection of one or more CCT setpoints of the CCT controller.