Driver Design and Simulation for 6W LED Bulb with PWM Dimming
Keywords:
Driver circuit, Efficacy, Junction temperature, Light emitting Diodes, Line voltage fluctuations, LT Spice, Lumens, ProteusAbstract
The growing awareness of the need to reduce energy cost has increased the popularity of Light Emitting Diodes (LED). Today,
LED’s claim to have more than 120 lumens/watt efficacy, more than 50,000 hours life time and compact size, making them
replace conventional lighting. Applications such as residential and commercial lighting require thousands of lumens, creating a
need to drive LED strings. LED works on DC power and therefore it requires a device that can convert incoming AC power to DC
voltage and regulate the current flowing through the LED during its operation. If the current exceeds manufacturer
recommendations, LED’s become brighter but their light output degrades due to the junction temperature rise and this may
reduce the useful life of LED. Since LED’s are very fast devices, if there is any variations in forward voltage, even for very short
time, it will cause big variation in current which may damage the LED. In order to avoid these problems and to protect LED from
line voltage fluctuations, a proper driver circuit is needed. In this paper the design of driver circuit for a 6W LED bulb with PWM
dimming capability with a buck converter is described. The simulation of the driver circuit done in LT Spice and Proteus and the
obtained results were also explained in this paper.
