Design and Prototyping of Dimmable LED Driver for General Lighting Application

Light emitting Diode technology (LED) has advanced rapidly which lead to development of brighter and long lasting sources. Due to growing awareness of the need to reduce energy cost, LED lighting is gaining popularity and also used in wide applications. LED's claim to have efficacy of 120 lumens per watt and lifetime of more than 50000 hours. Its compact size, varied colour of lights, higher efficacy and other advantages makes them replace conventional lighting. Applications such as residential and commercial lighting require thousands of lumens, creating a need to drive strings of LED. Irrespective of the driver topology linear regulator, buck, boost or buck-boost, the main aim is to drive the LED with constant current to control the light output. Some of the applications are as simple as ON and OFF, but many applications require dimming the output between 0 and 100 percent, often with fine resolution. The main objective of this work is to design a closed loop driver circuit with buck topology for a given load specification of LED string and include dimming features in it.