Design of a digital DC-DC converter

• Main Author: Guo, Jianhong.
• Other Authors: Tan Meng Tong
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Power electronics
• Online Access: http://hdl.handle.net/10356/15995
• Institution: Nanyang Technological University

Technological advancement has led to the creation of smaller and more sophisticated devices. The capability to maintain the reliability and stability of the DC-DC converters and regulating the low output voltage turn out to be a major concern for many researchers nowadays. In the recent years, major researches have been directed towards digital control which can offer higher flexibility, robustness and programmability in creating the next generation power converters. This report describes the design of a high frequency digital DC-DC buck converter that uses voltage mode control with digital feedback. The DC-DC converter consists of a power switching stage, a low pass filter stage and a digital feedback architecture comprising an Analog to Digital (A/D) converter, a digital compensator and a digital pulse width modulator (the key building blocks behind digital control). Two different techniques of digital compensation namely State Machine and Proportional-Integral-Derivative (PID) control are designed and implemented respectively with a fast clock DPWM scheme. The digital DC-DC converter was realized in Xilinx Virtex-4 FPGA board and a P160 analog module. Experimental results shows that the converter using PID digital control technique has achieved higher efficiency, tighter output regulation and higher speed dynamic response. This project has verified the superiority of integrated digital solution, thereby demonstrating the potential of digital DC-DC converters for newer generation applications.