FPGA based buck controller for LED white light tuning

New developmentsin solid state lighting allows us to use energy efficient LEDs in general lighting. Solid state lighting provides both energy and environmental benefits. One of the main specialties of LEDs over conventional light source is the controllability of its color temperature. This paper illustrates dynamic color temperature tuning of the multi colored LEDs to get different shades of white color using FPGA. The color tuning allows the user to control the human performance. The principle of additive color mixing algorithm is adopted for getting the desired white color from a set of multicolored LEDs. The control of intensity and color temperature is achieved by 4 channel current controlled buck converter by adjusting the PWM of each. The output current compensation for the LED is given by a type 2 PI controller. The proposed design and control algorithm assure very small color temperature variations and allows the user a full control over the luminance.