Modeling And Implementation Of Digital Controlled Multiphase DC-DC Converters

With the rapid development of microprocessors, the specifications for their power supplies become more and more stringent. It is required to maintain the output voltage within a tight tolerance with presence of large transient load current steps and slew rates.Digitally controlled multi-phase architecture based on identical DC-DC converter modules is presented. Digital voltage mode control is applied for voltage regulation, together with the digital active droop method for adaptive voltage positioning. The chain control algorithm is designed to obtain the average phase current. A parallel structure is developed for the voltage and current sharing regulation loops to avoid the bandwidth limitations in inner and outer loop structures. Closed loop modeling of a multi-phase converter with identical parameters in each phase shows that the voltage and current regulation loops are decoupled. The loop gains for voltage and current regulation alone are derived for compensator design. Simulation and statistical analysis are used to verify that the designed compensator meets system specifications within the given parameter distributions.Experiments in a two-phase 9V-to-1.5V 3A synchronous buck converter controlled by TMS320F2812 are performed to verify the system structure, loop design and control approaches presented in this thesis.