Abstract
LEDs for lighting application are becoming widely adopted due to economic, energy and environmental reasons. LEDs are conventionally powered by DC sources or AC sources with AC-DC converters. More and more recent research works have been focusing on direct AC powering LEDs without AC-DC converters. Enhanced reliability, lower cost and easy to replace existing lighting fixtures due to the elimination of AC-DC converter are advantages of AC LEDs. DC LED drivers architectures including AC-DC converter based LED drivers are reviewed and compared with direct AC powering LEDs. Issues like flicker effects, current limiting and protection, efficiency and LEDs reverse break down in AC LEDs and recent AC LEDs patents are discussed.
Keywords: Light Emitting Diodes, AC LED, LED Driver, Opto-Electronic Device, Lighting.
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