LED Controller Feedback for Luminance Consistency
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Solution Overview
Problem
LED lighting systems with constant current drivers often experience varying luminance intensity due to changes in AC voltage, leading to inconsistent brightness, which is undesirable for applications requiring consistent illumination.
Innovation Solution
An LED controller with path switches, a management center, and a line waveform sensor that divides LEDs into groups and adjusts the driving current to maintain a target value, independent of input voltage fluctuations, ensuring consistent luminance intensity across different AC voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If constant current drivers are used to control LEDs, then LED lifespan and energy efficiency are improved, but luminance intensity varies with AC voltage fluctuations
Solution Approach 1:
The patent implements a feedback mechanism where the controller detects the input voltage level and adjusts the driving current accordingly. When input voltage increases, the controller decreases the target current value to compensate, maintaining constant luminance output despite voltage fluctuations. This closed-loop control resolves the contradiction by using feedback to balance energy efficiency with luminance consistency.
Solution Approach 2:
The patent dynamically adjusts the target current value based on real-time input voltage conditions. Rather than using a fixed current setting, the system modifies operating parameters (current target values) in response to changing voltage conditions, enabling the LED driver to maintain consistent luminance across varying AC voltage inputs while preserving energy efficiency benefits.
2Loss of energy
If downstream LEDs are turned on and off based on input voltage thresholds, then power consumption is optimized, but luminance intensity becomes inconsistent
Solution Approach 1:
The patent changes the operating parameters (target current values) based on input voltage levels. Instead of simply turning LEDs on/off at fixed voltage thresholds, the system adjusts current magnitudes continuously or in steps according to voltage conditions, maintaining optimized power consumption while achieving consistent luminance output across different voltage inputs.
3Illumination intensity
If the target current value is increased to compensate for voltage drops, then luminance intensity is maintained, but power factor impact increases
Solution Approach 1:
The patent implements dynamic adjustment of target current values that decreases when input voltage increases. This opposite-direction adjustment strategy maintains luminance intensity by compensating for voltage drops without excessively increasing current during high-voltage conditions, thereby reducing harmful power factor impacts while preserving visible light output consistency.
Data Source
AI summary
LED controllers, LED lighting systems and control methods capable of providing an average luminance intensity independent from the variation of an AC voltage. LEDs are divided into LED groups electrically connected in series between a power source and a ground. A disclosed LED controller has path switches, a management center and a line waveform sensor. Each path switch is for coupling a corresponding LED group to the ground. The management center controls the path switches. When turning off an upstream path switch, the management center controls a downstream path switch for a downstream LED group to make the driving current passing the upstream LED group substantially approach a target value. The line waveform sensor is coupled to the power source, sensing the waveform of the input voltage of the power source. The line waveform sensor is configured to decrease the target value when the input voltage increases.