Energy efficient PWM Dimmable Smart Digital LED driver

Abstract

Lighting technology is progressing day by day from incandescent lamps, CFL, Induction lamps to the LEDs. LED is the future of lighting as it is having longer life greater than 50000 hours, absence of mercury, good light output, energy efficient. PWM dimming is used to control the brightness of LED. Proposed technology uses PIC16F877A microcontroller to generate PWM (Pulse Width Modulation) pulse applied as input to dimming input of constant current LED driver. Microcontroller generates PWM signal of 1.95 KHz frequency to automatically dim the LED module with respect to 24 hour. Because of which light output is reduced during the time when minimum amount of light intensity is required which results in huge energy saving. Ambient temperature is displayed on Liquid Crystal Display. Experiments are performed with various duty cycles of pulse width modulation technology and results are compared with traditional dimming technology suitable for automatic dimming feature. PWM technology possesses highest efficiency of 90 percent. It was also found that as we dim the LEDs, junction temperature also reduces which does elongates the lifetime of LED module.