Current Channeling Circuit for Wide-Range CCT Tuning
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Solution Overview
Problem
Existing tunable white lighting systems face challenges in achieving a wide range of color temperature tunability between 2700K and 6500K, as using only two LEDs results in color points being far below the black body locus, requiring additional LEDs and complex three-channel drivers, which are costly and complex.
Innovation Solution
An interface currents channeling circuit converts two-channel driver outputs into three driving currents, allowing a two-channel driver to power two LED arrays at the ends of a desired range and a third array in the middle, achieving three-step MAE BBL color temperature tunability using a two-channel driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two LED arrays are used with a two-channel driver, then device complexity is reduced, but color temperature tunability range is limited and color points fall far below the black body locus
Solution Approach 1:
The patent segments the lighting system into three separate LED arrays (first, second, and third arrays) with different color characteristics, each controlled by independently adjustable currents. This segmentation allows precise control over the mixed light's color temperature, enabling the system to achieve color points on the black body locus while maintaining relatively simple circuitry through the use of a two-channel driver with current channeling.
2Adaptability or versatility
If three LED arrays are used to achieve wide color temperature tunability, then color temperature range is improved, but device complexity increases
Solution Approach 1:
The patent employs a two-channel driver that performs multiple functions: it directly controls two LED arrays and, through the current channeling circuit, indirectly controls a third LED array. This multi-functionality allows the system to achieve three-array color mixing capability with only a two-channel driver, reducing overall device complexity while maintaining wide color temperature tunability and achieving color points on the black body locus.
Solution Approach 2:
The current channeling circuit acts as an intermediary between the two-channel driver and the three LED arrays. It converts the two independent current channels from the driver into three controlled current outputs, enabling the driver to power all three arrays with different current levels. This intermediary component resolves the complexity issue by providing intelligent current distribution without requiring a more complex three-channel driver.
3Adaptability or versatility
If additional LEDs are added to expand color temperature range, then color temperature tunability is improved, but manufacturing cost increases
Solution Approach 1:
The two-channel driver is designed to perform multiple functions by controlling three LED arrays through current channeling. This multi-functionality eliminates the need for an expensive three-channel driver, reducing manufacturing costs while still achieving wide color temperature tunability (2700K-6504K) and precise color control on the black body locus.
Solution Approach 2:
The patent controls color temperature by changing the current parameters (intensity levels) supplied to three different LED arrays with distinct color characteristics. By adjusting the relative current levels to each array, the system can dynamically shift the mixed light's color temperature across a wide range while maintaining cost-effectiveness through the use of a simpler two-channel driver 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
This solution enables reduced circuit complexity, size, and cost while providing wide-range color temperature tunability, ensuring color points are closer to the black body locus, enhancing user preference and system efficiency.
Implementation Method 1
a first LED array, a second LED array, and a third LED array, each having a different correlated color temperature (CCT)
Implementation Method 2
By appropriate brightness control of the three LED light sources, a mixed light can be generated, the color point is virtually on the black body curve
Data Source
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AI summary
An interface currents channeling circuit may be used to convert two current channels of a conventional two-channel driver into three driving currents for the three strings of LEDs. By doing so, the same two channel driver can be used for applications requiring just two LED arrays as well as three LED arrays.