LED Circuit Dimming Control for Warm Color Temperature Shift
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Solution Overview
Problem
Conventional LED lighting systems lack the ability to dynamically control color temperature in response to changes in brightness, failing to replicate the warm color temperature adjustment similar to incandescent bulbs when dimmed.
Innovation Solution
A lighting apparatus with a circuit design that includes multiple stages of LEDs connected in parallel, each with different color temperatures and resistors, and a driving current controller that adjusts the current levels based on a dimming signal, allowing for precise control of color temperature by varying the driving currents through the stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional LED lighting systems are used with a single color temperature, then the structure is simple and energy efficient, but the ability to dynamically control color temperature in response to brightness changes is lost
Solution Approach 1:
The LED lighting system is divided into multiple independent current paths, each containing LEDs with different color temperatures. This segmentation allows each path to be controlled independently, enabling dynamic color temperature adjustment while maintaining a modular and manageable circuit structure.
Solution Approach 2:
The circuit incorporates dynamic control mechanisms where the driving currents through different color temperature LED paths are adjusted based on dimming levels. This dynamic adjustment enables the system to automatically change color temperature in response to brightness changes, replicating the incandescent bulb effect.
2Adaptability or versatility
If multiple LED stages with different color temperatures are connected in parallel, then color temperature control is enabled, but the device complexity increases
Solution Approach 1:
Each current path in the parallel configuration serves multiple functions: it provides both illumination and color temperature control. The resistors in series with each LED stage serve dual purposes of current limiting and color temperature adjustment, reducing the need for additional dedicated components.
Solution Approach 2:
The system controls color temperature by changing the driving current parameters through each parallel path. By adjusting the current levels in response to dimming signals, the system achieves continuous color temperature variation without requiring complex mechanical or optical switching mechanisms.
3Illumination intensity
If the driving current through LED stages is increased to improve brightness, then illumination intensity improves, but energy consumption increases
Solution Approach 1:
Different current paths are assigned different quality characteristics based on their LED color temperatures and forward voltage drops. The control system selectively activates and adjusts current through specific paths based on the desired brightness level and color temperature, optimizing energy distribution rather than uniformly increasing current through all paths.
Solution Approach 2:
The system uses partial action by selectively activating only the necessary LED paths required to achieve the desired brightness level. At lower dimming levels, only certain color temperature paths are activated, avoiding the energy waste of driving all LED stages at full current regardless of need.
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 the lighting apparatus to adjust color temperature in response to dimming levels, providing a similar warm light experience to incandescent bulbs and enhancing user control over light output.
Implementation Method 1
A lighting apparatus including light-emitting diodes (LEDs) may convert an AC voltage into a rectified voltage and cause the LEDs to emit light depending on the level of the rectified voltage
Data Source
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AI summary
A lighting apparatus including an LED circuit including a plurality of serially connected stages configured to receive a modulated rectified voltage, each of the stages including a first path including a first resistor and a first LED connected in series, and a second path connected to the first path in parallel and including a second LED configured to emit light having a color temperature different from that emitted from the first LED, and a driving current controller configured to adjust an intensity of light output from the LED circuit by adjusting currents applied to driving nodes connected to the stages, depending on a dimming signal associated with a dimming level of the rectified voltage, in which a threshold voltage of the first LED is lower than that of the second LED.