SCR Dimming Circuit for Uniform LED Brightness
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Solution Overview
Problem
SCR dimming methods for LED lamps result in non-uniform brightness due to large phase angles, leading to poor visual effects as not all LED lamps are turned on when the input voltage is insufficient.
Innovation Solution
A method and device that adjust the phase angle of a SCR switch to generate a stable direct current signal, which is rectified and used to control the output current adjusting circuit, allowing all connected LED lamp groups to be turned on or off uniformly by adjusting the phase angle of the SCR switch, utilizing an N-channel MOS transistor to manage the voltage and resistance for optimal brightness control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SCR switch phase angle is increased for dimming control, then power factor and harmonic distortion are improved, but LED lamp brightness uniformity deteriorates
Solution Approach 1:
The patent introduces a stable direct current signal as an intermediary between the SCR switch phase angle and the LED lamp groups. This signal mediates the control relationship, ensuring that when the phase angle changes, all LED lamp groups receive uniform control signals through the rectified and converted direct current, preventing the non-uniform brightness that would otherwise occur with direct phase angle control.
2Reliability
If SCR switch phase angle is increased for dimming control, then power factor is improved, but LED lamp turning on completeness deteriorates
Solution Approach 1:
The stable direct current signal generated by rectifying and converting the SCR switch output serves as a mediator that ensures complete and uniform turning on of all LED lamp groups. This intermediary signal processing step guarantees that even when phase angle is large, the control signal is sufficient to turn on all LED lamps uniformly, rather than causing partial turning on.
3Ease of operation
If phase angle control is used for dimming, then dimming function is achieved, but visual effect deteriorates due to non-uniform brightness
Solution Approach 1:
The patent uses a stable direct current signal as an intermediary to improve the visual effect while maintaining the dimming function. This signal is generated by rectifying and converting the SCR switch output, and it uniformly controls all LED lamp groups, ensuring that the dimming effect is achieved without the non-uniform brightness that would otherwise degrade the visual effect.
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 ensures uniform brightness and improved visual effect by controlling the LED lamp groups to turn all on or all off based on the stable direct current signal corresponding to the SCR switch's phase angle, addressing the non-uniformity issue and enhancing the visual impact.
Implementation Method 1
adjusting a phase angle of a SCR switch and outputting an alternating current signal related to the phase angle of the SCR switch
Implementation Method 2
rectifying the alternating current signal
Data Source
AI summary
A method for generating a stable direct current signal, a silicon controlled switch dimming method and device, the silicon controlled switch dimming method comprising: adjusting a phase angle of a silicon controlled switch and outputting an alternating current signal related to the phase angle of the silicon controlled switch (S101); rectifying the alternating current signal (S102); converting the rectified electric signal into a steady direct current signal one-to-one corresponding to the phase angle of the silicon controlled switch, and the stable direct current signal decreases as the phase angle of a silicon controlled switch increases (S103); controlling turning on or off of an output current regulating circuit according to the magnitude of the stable direct current signal so as to control the plurality of serially connected LED lamp groups to be turned all on or all off (S104). The generated stable DC signal one-to-one corresponds to the phase angle of the silicon controlled switch and decreases with the increase of the phase angle of the silicon controlled switch. The stable direct current signal can control work status of the plurality of LED lamp groups connected in series, thereby making the plurality of LED lamp groups connected in series be turned all on or all off.