Design, modeling and simulation of DC-DC converter for low voltage applications

This paper presents design, modeling and simulation of a low-power digitally controlled synchronous rectifier (SR) buck converter. Due importance is given in the model to the effect of non-linear parameters in low voltage converters, such as equivalent series resistance ESL of the inductor, ESR of capacitor and R_DS(on) of MOSFET switches. A digital PID controller is design adopting direct digital design approach, further to improve its transient response the design is modified to achieve Auto-tuned discrete PID Controller (AT-PID).The performances of two controllers are compared. Simulations of a digital control synchronous buck are performed with Matlab/Simulink. The simulation results show that the approach enables high-speed dynamic performance.