TRIAC Dimmer Bleeder Switching for LED Current Hold Control
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Solution Overview
Problem
Conventional LED lighting systems with TRIAC dimmers face inefficiencies due to high power consumption by the bleeder unit, which affects the operation efficiency and can lead to malfunction if the current falls below a holding current.
Innovation Solution
A high-efficiency TRIAC dimmer switch control system is introduced, comprising a constant current control unit, a bleeder unit, and a bleeder control unit, which dynamically controls the bleeder circuit by generating control signals based on sensing signals to optimize power usage and maintain normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bleeder unit operates continuously to maintain TRIAC dimmer operation, then the reliability of the dimmer is improved, but the power consumption increases
Solution Approach 1:
The bleeder unit is controlled to operate periodically rather than continuously. The control system activates the bleeder unit only during specific periods when the LED current is insufficient to maintain TRIAC dimmer operation, thereby reducing overall power consumption while ensuring reliable dimmer operation when needed.
Solution Approach 2:
The system uses feedback from current sensing to control the bleeder unit operation. The control circuit monitors the LED current and adjusts the bleeder unit activation based on the sensed current level, ensuring the bleeder operates only when necessary to maintain the holding current threshold for reliable TRIAC dimmer operation.
2Reliability
If the bleeder unit operates continuously to prevent malfunction, then the system reliability is improved, but the overall system efficiency deteriorates
Solution Approach 1:
The bleeder unit is activated periodically based on system conditions rather than operating continuously. This periodic operation maintains system reliability by ensuring TRIAC dimmer function when LED current is insufficient, while minimizing energy loss by keeping the bleeder inactive during periods when LED current is adequate.
Solution Approach 2:
The bleeder unit operation is made dynamic and adaptive to system conditions. The control circuit adjusts the bleeder activation status in real-time based on the LED current level, transitioning between active and inactive states to optimize the balance between reliability and energy efficiency.
3Reliability
If the bleeder current is increased to ensure TRIAC dimmer operation, then the reliability is improved, but the power loss increases
Solution Approach 1:
The bleeder unit provides current periodically rather than continuously. By activating the bleeder only during AC cycles or periods when LED current falls below the holding current threshold, the system ensures reliable TRIAC dimmer operation when needed while minimizing the total energy loss associated with bleeder current.
Solution Approach 2:
The system dynamically changes the bleeder current parameter based on operating conditions. The control circuit adjusts whether the bleeder is active or inactive, effectively changing the bleeder current from a continuous value to a conditional value that is non-zero only when necessary for reliable TRIAC dimmer operation.
Data Source
AI summary
System and method for controlling one or more light emitting diodes. For example, the system for controlling one or more light emitting diodes includes a current generator configured to generate a first current flowing through one or more light emitting diodes. The one or more light emitting diodes are configured to receive a rectified voltage generated by a rectifying bridge coupled to a TRIAC dimmer. Additionally, the system includes a bleeder configured to receive the rectified voltage, and a controller configured to receive a sensing voltage from the current generator and output a control signal to the bleeder. The sensing voltage indicates a magnitude of the first current.