LED Lighting Unit with Inverter Circuit Color Control
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Solution Overview
Problem
Existing LED lighting systems operated by a DC power supply lack the capability for both dimming and color control, as they can only provide dimming through pulse width modulation without changing the color of the light output.
Innovation Solution
An LED lighting unit incorporating an inverter circuit that cycles between multiple states to control the supply connections to antiparallel LED groupings, allowing for adjustable ratios of time periods to achieve color and dimming control, utilizing an H-bridge circuit with switches to manage the LED connections and current sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a DC power supply with PWM dimmer is used to control LEDs, then dimming capability is provided, but color control capability is lost
Solution Approach 1:
The LED lighting system segments the LED load into two antiparallel groups (first and second LED groups) that can be independently controlled. The inverter circuit separately manages current flow to each group through distinct switching paths, enabling independent control of each group's illumination duration and intensity. This segmentation allows the system to vary the ratio of illumination time between the two groups to achieve color temperature adjustment while maintaining dimming capability through overall duty cycle control.
2Adaptability or versatility
If an inverter circuit with antiparallel LED groups is used, then both dimming and color control are achieved, but device complexity increases
Solution Approach 1:
The inverter circuit is designed as a multi-functional device that simultaneously performs dimming control and color temperature adjustment. By integrating the H-bridge switching architecture with duty cycle modulation capability, the circuit achieves both functions through a single unified control system rather than requiring separate dimming and color control circuits, thereby reducing overall system complexity despite the advanced functionality.
Solution Approach 2:
The inverter circuit employs periodic switching cycles that alternate between illuminating the first LED group and the second LED group. Each cycle consists of sequential illumination periods for each group, with the duration ratios programmably controlled. This periodic action enables color temperature modulation through temporal mixing of different color outputs while maintaining simple average current control for dimming, achieving complex functionality through time-based modulation rather than complex simultaneous control.
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 independent control of color temperature and light intensity, providing a solution for both dimming and color adjustment using a DC power supply, enhancing the functionality of LED lighting systems.
Implementation Method 1
LED lighting unit with color and dimming control... LED module having a pair of antiparallel LED groupings... The inverter circuit can cycle between at least a first state, a second state, and a third state
Data Source
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AI summary
Method and apparatus for a LED lighting unit (200), including an inverter circuit (210) electrically coupled to a LED module (220) having a pair of antiparallel LED groupings. The inverter circuit (210) provides for color and/or dimming control of the LED module (220). A method of adjusting color and/or dimming of a LED module includes the step of cycling between a plurality of states during each of a plurality of time periods.