LED Lighting Device with Flicker Controller for AC Power
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Solution Overview
Problem
When alternating current (AC) power is directly applied to LEDs without an AC rectifier, the on/off states of the LEDs are affected by the input voltage, leading to flicker and reduced light output efficiency due to variable current flow.
Innovation Solution
A lighting device with a flicker controller and bypass units that manage current flow between light-emitting groups, switching between serial and parallel connections based on input voltage levels to maintain consistent light output and prevent flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If AC power is directly applied to LEDs without an AC rectifier, then device complexity is reduced, but light output stability deteriorates causing flicker
Solution Approach 1:
The LED lighting system is divided into multiple light-emitting groups (first light-emitting group, second light-emitting group, etc.) that can be independently controlled. Each group can be selectively connected to the power supply through switching elements, allowing the system to segment the current path and maintain stable operation by preventing simultaneous on/off transitions of all LEDs.
Solution Approach 2:
A flicker controller is introduced as an intermediary device between the AC power supply and the LED groups. This controller includes switching elements that mediate the current flow, preventing direct connection of all LEDs to the fluctuating AC voltage and thereby eliminating flicker while maintaining relatively simple circuitry.
2Device complexity
If LEDs are connected in series to handle AC power directly, then device complexity is reduced, but light output efficiency deteriorates due to variable current flow
Solution Approach 1:
The circuit configuration dynamically switches between series and parallel connections of LED groups based on the AC voltage cycle. During different half-cycles, the flicker controller reconfigures the circuit topology to maintain optimal current flow through the LEDs, ensuring high light output efficiency while adapting to the varying AC voltage without requiring complex rectification circuits.
Data Source
AI summary
Disclosed is a light-emitting device configured in such a manner that all light-emitting elements always emit light irrespective of the magnitude of an input voltage when the magnitude of the voltage is higher than the minimum light-emitting voltage, and that the light-emitting elements are connected to each other in parallel when the magnitude of the voltage is small, and connected to each other in series when the magnitude of the voltage is large.