LED Driving Circuit Flicker Reduction via Sequential Mode
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Solution Overview
Problem
Existing light emitting diode (LED) driving circuits face challenges in efficiently operating with alternating current (AC) power, leading to increased complexity and manufacturing costs, and often result in flicker issues when transitioning between high and low forward voltage levels.
Innovation Solution
A driving circuit that includes a dimmer to modulate AC voltage based on selected dimming levels, a full-wave rectifier to generate driving voltage, and a driving module that selects between stop, resistance, and sequential driving modes to improve flicker reduction and light efficiency, utilizing a bleeder circuit to control bleeder current in conjunction with a TRIAC dimmer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate circuits such as switching mode power supply are used to drive LED with AC power, then LED can be driven by AC power, but circuit complexity increases and manufacturing costs rise
Solution Approach 1:
The LED lighting system is divided into multiple independently controllable LED groups (first LED group, second LED group, third LED group) with different forward voltage levels. Each group can be selectively activated based on the input voltage level, allowing AC power adaptation without requiring complex power conversion circuits. The segmentation enables direct AC driving while maintaining circuit simplicity.
2Adaptability or versatility
If sequential driving scheme is used to drive multiple LED groups with AC power, then AC power driving is achieved, but flicker occurs when transitioning between high and low forward voltage levels
Solution Approach 1:
A bleeder circuit is implemented to pre-charge the bleeder capacitor during the voltage transition period before LED groups are switched. This preliminary action ensures that when transitioning from high forward voltage level to low forward voltage level, the bleeder capacitor maintains sufficient charge to prevent flicker by providing continuous current to the dimmer circuit, thus eliminating the harmful flicker effect during mode transitions.
3Use of energy by moving object
If sequential driving scheme is used to improve light efficiency, then light efficiency is improved, but flicker occurs during voltage transitions
Solution Approach 1:
The bleeder capacitor acts as an intermediary energy storage element between the rectifier circuit and the LED groups. During sequential driving transitions, the bleeder capacitor mediates the voltage changes by maintaining a stable voltage level, ensuring continuous current flow to prevent flicker while allowing the sequential driving scheme to maintain high light efficiency. The dimmer circuit also serves as an intermediary to smoothly control transitions between different LED group configurations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces flicker, enhances light efficiency, and improves electrical characteristics by dynamically adjusting driving modes based on dimming levels, ensuring stable operation of LED groups across varying voltage conditions.
Implementation Method 1
a rectifier full-wave rectifying the modulated AC voltage output from the dimmer to generate and output a driving voltage
Implementation Method 2
a light emitting diode (LED)
Data Source
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AI summary
Disclosed herein are a driving circuit and a lighting apparatus for a light emitting diode capable of improving a flicker, light efficiency, and electrical characteristics. The disclosed driving circuit for a light emitting diode includes: a dimmer modulating an AC voltage input depending on a selected dimming level; a rectifier full-wave rectifying the modulated AC voltage output from the dimmer to generate and output a driving voltage; and a driving module receiving the driving voltage of the rectifier to detect the selected dimming level and controlling a driving mode of a plurality of light emitting diode groups depending on the detected dimming level, in which the driving module selects one of a resistance driving mode driving all the plurality of light emitting diode groups and a sequential driving mode sequentially driving the plurality of light emitting diode groups to improve light efficiency and electrical characteristics.