A design for an RGB LED driver with independent PWM control and fast settling time

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (leaves 76-77).A small sized and efficient method to power RGB LEDs for use as backlights in flat panel displays is explored in this thesis. The proposed method is to drive a parallel switched connection of LEDs with a single Average Mode Controlled buck regulator.Specifications for the switching regulator and control circuitry are described. The application circuit demonstrates current settling times between 7[mu]s and 30[mu]s at a switching frequency of 290kHz. Current settling is improved at higher switching frequencies, with settling times approaching a 2[mu]s to 4[mu]s range at 1MHz switching.by Awo Dede O. Ashiabor.M.Eng