High-Performance Current-Mode-Controller Design of Buck LED Driver With Slope Compensation

A discrete time domain modeling and analysis for the current-mode-controlled (CMC) buck LED driver with slope compensation is presented in this paper. The discrete time domain equation representing the buck LED driver is derived and linearized about the equilibrium state. Also, the switching control law, the proportional-integral compensator is used here as an example of the error amplifier, is linearized about the equilibrium state. The linearized buck LED driver and the control law are then combined to arrive at a linearized CMC buck LED driver. The root-locus method is employed to analyze the closed-loop system. The design guidelines and experimental results for the CMC buck LED driver are presented.