The Comparison of the LED Driving and Controlling Circuits

Ben Qian R&D Department

Shanghai Sunlight Opto. Device Co., LTD

Shanghai, China

ben@cool-led.com

Abstract-Along with the continual improvement of the LED’s power and energy efficiency, we see a trend that the LED of high luminance is gradually replacing the traditional lighting sources. LED is also widely used in the automobile lighting, but currently only for each kind of internal lighting and the external lighting as rear signal lamps. Although most LEDs work with a low power, it is certain that the continual improvement of the manufacturing technology and the declining of the cost of the LED will make it possible to see a growing application of the LED in external lighting, even the head lamps. The research of the driving power sources of the high-power LED seems pressing and challenging. At present, the switch converter is of the highest energy efficiency and the best performance among the LED DC driving circuits. Such DC converters are generally used in the regulated power supplies before, while the LED can only be used after adjusting and optimizing all the DC-DC converters because they have to work in constant current power supplies based on its optical and electrical characteristics. This paper mainly elaborates on the merits and the demerits of each kind of LED driving circuit.

Keywords-LED;constant;current BUCK-BOOST; FLYBACK; SEPIC; CUK BOOST BUCK