Bleeder Controller for TRIAC Dimmer LED Current Stability
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Solution Overview
Problem
Conventional LED lighting systems using TRIAC dimmers face challenges in maintaining stable LED current due to the reduced input power required for equivalent illumination compared to incandescent lights, leading to instability and potential blinking of LEDs.
Innovation Solution
A system for controlling LEDs that includes a current regulator, a bleeder controller, and a bleeder unit, where the bleeder controller generates a bleeder control signal based on the LED current and rectified voltage, allowing or disallowing the generation of a bleeder current to maintain stable operation of the TRIAC dimmer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If TRIAC dimmers are used with LED lighting systems, then the lighting system can achieve dimming functionality, but the LED current becomes unstable and LEDs may blink due to reduced input power requirements
Solution Approach 1:
The patent implements a feedback mechanism where the bleeder control unit continuously monitors the LED current and adjusts the bleeder current accordingly. When LED current is detected to be unstable or when dimming is not actively used, the system automatically activates the bleeder unit to provide compensation current, thereby maintaining stable LED operation and preventing blinking while preserving dimming functionality.
Solution Approach 2:
The system dynamically changes the parameter of bleeder current based on operating conditions. The bleeder control unit adjusts the bleeder current magnitude according to the detected LED current level and dimming state, transitioning between different operating modes (with/without bleeder compensation) to maintain optimal LED performance across various dimming levels.
2Reliability
If bleeder units are added to compensate for reduced input power, then TRIAC dimmer holding current requirements are met, but the device complexity increases
Solution Approach 1:
The bleeder unit is designed with multi-functionality, serving both as a compensation mechanism for maintaining TRIAC holding current and as a protective feature against LED blinking. The same circuit components (transistor, resistor, capacitor) perform multiple functions: providing bleeder current when needed, maintaining stability during dimming, and protecting the LED circuit from instability, thereby reducing the need for separate dedicated components.
Solution Approach 2:
The bleeder control unit automatically detects when bleeder current is needed based on LED current monitoring and activates the bleeder unit accordingly. The system self-regulates by continuously monitoring its own state and adjusting the bleeder current without external intervention, making the added complexity self-managing and reducing the need for additional control circuits.
Data Source
AI summary
System and method for controlling one or more light emitting diodes. For example, the system includes: a current regulator including a first regulator terminal and a second regulator terminal, the first regulator terminal being configured to receive a diode current flowing through the one or more light emitting diodes, the current regulator being configured to generate a sensing signal representing the diode current, the second regulator terminal being configured to output the sensing signal; a bleeder controller including a first controller terminal and a second controller terminal, the first controller terminal being configured to receive the sensing signal from the second regulator terminal, the bleeder controller being configured to generate a first bleeder control signal based at least in part on the sensing signal, the second controller terminal being configured to output the first bleeder control signal.