SCR Dimming Circuit for LED Luminance Control
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Solution Overview
Problem
Conventional SCR dimming circuits for LED loads suffer from low efficiency, flickering, and inadequate dimming performance due to limited adjustability of the dimming phase angle range, which restricts luminance control and power factor optimization.
Innovation Solution
An SCR dimming circuit that includes an SCR element, a rectifier bridge, a conduction angle generator, and a dimming signal generator, which converts sinusoidal AC power to lack-phase AC and DC voltages, and generates a dimming signal to regulate LED luminance by adjusting the dimming phase angle range, allowing for higher efficiency, reduced flickering, and improved power factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional SCR dimming circuits are used to control luminance by cutting off input sine wave, then dimming operation is achieved, but efficiency is low and flicker occurs
Solution Approach 1:
The patent implements dynamic adjustment of the dimming phase angle range through a dimming signal generator that receives a dimming signal and adjusts the conduction angle of the SCR element. This allows the circuit to adaptively optimize the balance between luminance control and energy efficiency by varying the phase angle range rather than using fixed conventional dimming approaches
Solution Approach 2:
The patent changes the parameter of phase angle range from fixed to adjustable. By modifying the phase angle range within which the SCR element conducts, the circuit can optimize energy efficiency while maintaining luminance control capability, directly addressing the efficiency-flicker contradiction
2Illumination intensity
If conventional SCR dimming circuits are used, then dimming operation is achieved, but flicker is produced
Solution Approach 1:
The patent uses dynamic adjustment of the dimming phase angle range to eliminate flicker. The dimming signal generator continuously adjusts the conduction angle within an optimized phase angle range, ensuring smooth luminance transitions without the abrupt changes that cause flicker in conventional fixed-phase-angle circuits
3Adaptability or versatility
If the dimming phase angle range is fixed, then the circuit is simple, but adjustability and dimming performance are limited
Solution Approach 1:
The patent implements a multi-functional dimming signal generator that can adjust the phase angle range dynamically while maintaining circuit simplicity. The same circuit structure provides both dimming control and adaptability adjustment, eliminating the need for separate complex adjustment mechanisms and achieving versatile dimming performance without proportionally increasing complexity
Solution Approach 2:
The patent introduces dynamic adjustability through the dimming signal generator that can modify the phase angle range in real-time. This dynamic capability enhances dimming performance and adaptability while keeping the overall circuit structure relatively simple by integrating the adjustment function into the existing dimming control architecture
4Power
If the dimming phase angle range is not optimized, then the circuit is easy to implement, but power factor is suboptimal
Solution Approach 1:
The patent optimizes power factor by dynamically changing the phase angle range parameter. The dimming signal generator adjusts the conduction angle within an optimized range that maximizes power factor, transforming the circuit from a simple fixed-parameter implementation to an optimized variable-parameter system without requiring complex external control mechanisms
Data Source
AI summary
The present invention relates to an SCR dimming circuit and method for regulating the luminance of an LED load. In one embodiment, an SCR dimming circuit can include: an SCR element that generates a lack-phase AC voltage based on a sinusoidal AC supply; a rectifier bridge that generates a lack-phase DC voltage based on the lack-phase AC voltage; a conduction angle generator that receives the lack-phase DC voltage, and generates a controlling signal representative of a conduction angle of the SCR element; and a dimming signal generator that generates a dimming signal to regulate luminance of the LED load, where the dimming signal generator receives the controlling signal, an adjustable signal, and a clamping voltage, an amplitude of a dimming phase angle range is selected by a fixed signal determined by the clamping voltage, and the dimming phase angle range may be shifted by regulating the adjustable signal.