Light Emitting Diodes (LEDs) has become the next generation lighting solutions due to rapid advancement of solid-state lighting technology. Colour consistency is the main issue for multi-colour LEDS. Change in temperature of the LED pn junction leads to changes in light output, wavelength and spectral width. Changing colour consistency creates adverse effects on human perception and comfort. So it is essential to maintain the colour consistency of LED string. This paper proposes a LED driver that controls colour (CCT) by considering the temperature effect on LED voltages. By Nonlinear optimization of LED voltages and the LED currents, CCT deviation are minimized. The optimum LED currents are fed to the feedback controller which adjusts the current to obtain the desired light output for least CCT deviation. Power parameters like Power Factor and THD have been improved to reduce power loss. The system stability has been determined. System performances show that the LED driver is working well.

CCT, LED, photodiode, feedback controller