TRIAC Dimmer LED Control Circuit Flicker Reduction
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Solution Overview
Problem
Conventional TRIAC dimmer systems for LED lighting suffer from flickering issues when the conduction angle is low or AC input voltage is high, leading to undesirable brightness variations and user perception of flicker.
Innovation Solution
The system employs signal processing components and comparators to determine the condition of the TRIAC dimmer, generating signals to control the switch's operation, ensuring stable output by adjusting the switch's state based on modulation frequency and duty cycle, thereby maintaining consistent brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional TRIAC dimmer systems are used for LED lighting, then the system can operate with simple control circuitry, but flickering occurs when conduction angle is low or AC input voltage is high
Solution Approach 1:
The system performs preliminary detection of TRIAC dimmer conditions (conduction angle, AC input voltage) before LED driving begins. The controller detects whether the TRIAC dimmer is in a first condition (conduction angle ≥ threshold and AC voltage ≤ threshold) or second condition (conduction angle < threshold or AC voltage > threshold), and prepares appropriate driving strategies in advance to prevent flickering
Solution Approach 2:
The system dynamically adjusts the LED driving strategy based on real-time TRIAC dimmer conditions. When in the first condition, the controller drives LEDs with dynamic switching (opened and closed at modulation frequency). When in the second condition, the controller maintains the switch closed for extended periods until conditions change, adapting the driving mode to prevent flickering
2Illumination intensity
If the TRIAC dimmer conduction angle is reduced to achieve dimming, then the LED brightness can be reduced, but flickering increases
Solution Approach 1:
The system dynamically changes the switch control strategy based on conduction angle detection. When conduction angle is sufficient (first condition), normal dynamic switching occurs at modulation frequency for smooth dimming. When conduction angle becomes too low (second condition), the system extends the closed period of the switch to maintain continuous current flow and eliminate flickering
Solution Approach 2:
The system changes the operating parameters of the LED driver based on detected conditions. By adjusting when the switch opens and closes based on conduction angle and voltage levels, the system maintains stable LED operation across different dimming levels without flickering
3Power
If the AC input voltage is increased to improve power delivery, then the power supply capability is enhanced, but flickering occurs
Solution Approach 1:
The controller detects AC input voltage levels before LED driving and prepares appropriate control strategies. When high voltage is detected (second condition), the system adjusts switch timing to accommodate the higher voltage input, preventing flickering while maintaining power delivery capability
Solution Approach 2:
The system continuously monitors AC input voltage and TRIAC conduction angle, providing feedback to the controller. Based on this feedback, the controller adjusts the switch control signals to maintain stable LED operation regardless of voltage fluctuations or dimmer settings
Data Source
AI summary
System and method for dimming control of one or more light emitting diodes. An example system includes one or more signal processing components configured to receive a first signal associated with a TRIAC dimmer, process information associated with the first signal, determine whether the TRIAC dimmer is in a first condition or a second condition, generate a second signal based on at least information associated with the first signal, and send the second signal to a switch. The one or more signal processing components are further configured to, if the TRIAC dimmer is determined to be in the first condition, generate the second signal to cause the switch to be opened and closed corresponding to a modulation frequency.