Linear Dimming LED Driver Circuit Color Temperature Adjustment
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Solution Overview
Problem
Conventional LED lamp driving devices face issues with color temperature errors due to the physical properties of blue-light and yellow-light LEDs, leading to reduced yield rates and increased defect inventory, and they are costly with complex circuit architectures that do not allow for flexible dimming and color adjustment.
Innovation Solution
A linear dimming LED driver circuit with a single-stage modulation technique that includes a dimming module, rectification module, conversion module, and control module, using a full-wave bridge rectifier and tri-electrode AC switch to adjust the color temperature by dividing LED strings into specific groups and using a switch to change the color temperature, maintaining a constant driving voltage within 129-135V for improved efficiency and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional multi-stage modulation is used to adjust brightness, then excellent working efficiency is achieved, but specific component cost is incurred and circuit complexity increases
Solution Approach 1:
The patent segments the LED strings into multiple groups (first group, second group, third group) with different color temperatures. By controlling which groups are activated, the system achieves both brightness adjustment and color temperature regulation, replacing the need for complex multi-stage modulation circuits while maintaining high working efficiency.
Solution Approach 2:
The patent makes the LED string groups serve multiple functions: they simultaneously provide brightness control and color temperature adjustment. The same LED groups that emit light also determine the overall color temperature when combined in different ratios, eliminating the need for separate control circuits for each function.
2Illumination intensity
If blue-light LEDs and yellow-light LEDs are mixed to produce required light color, then the lamp can achieve desired color temperature, but color temperature errors occur due to physical properties of different LEDs
Solution Approach 1:
The patent divides LED strings into distinct groups with specific color temperature characteristics (first group, second group, third group). Each group has controlled local quality in terms of color temperature, allowing precise overall color temperature control by adjusting which groups are activated, thereby reducing color temperature errors.
Solution Approach 2:
The patent changes the operating parameters by controlling the conduction angle of each LED string group independently. By adjusting the conduction angle parameters of different color temperature groups, the system achieves precise color temperature control and compensates for physical property variations in different LED types.
3Ease of operation
If the conduction angle of input voltage is adjusted to change brightness, then dimming function is achieved, but the driving voltage changes in stages which affects energy conversion efficiency
Solution Approach 1:
The patent dynamically controls the conduction angle of each LED string group independently based on the required brightness and color temperature. This dynamic adjustment allows continuous dimming without stage-based voltage changes, maintaining optimal energy conversion efficiency across the entire dimming range.
Solution Approach 2:
The patent uses periodic AC waveform control with adjustable conduction angles for each LED group. By controlling which groups conduct during different portions of the AC cycle, the system achieves smooth dimming and color temperature adjustment without multi-stage voltage switching, preserving energy conversion efficiency.
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
The solution allows for flexible adjustment of light color and improved dimming range while maintaining high energy conversion efficiency and reducing component costs, enabling better control over the brightness and color temperature of LED lamps.
Implementation Method 1
the rectification module is a full-wave bridge rectifier
Implementation Method 2
driving a plurality of LED strings to emit light
Data Source
AI summary
A linear dimming LED driver circuit capable of adjusting color temperature used in a lamp of a down light or a tube light to drive a plurality of LED strings to emit light and the LED strings are formed by yellow-light and ultra blue LEDs. The circuit uses a switch to switch the conduction of the LED strings to change the color temperature of the light emission of the lamp, so that the control module will adjust the light emitting brightness of the lamp for better dimming range and work performance of the whole circuit if a driving voltage is in a mono sinusoidal voltage section greater than or equal to 129 volts and smaller than or equal to 135 volts.