Analysis and design of a forward power converter

With advances in microelectronic fabrication and semiconductor devices, the size of electronic equipment is ever decreasing. Virtually, every piece of electronic equipment is powered from a DC power source, be it a battery or a DC power supply. The power supply constitutes to a main portion of any electronic device. Therefore, the key requirements for a power supply are lighter weight, reduced size, and reduced heat dissipation. There have been two technologies in power supplies: Linear and Switched mode. Though linear supplies have many desirable characteristics such as simplicity, low output ripple, excellent line and load regulation, fast response time to line or load changes, and low EMI, they suffer from poor efficiency and occupy large volumes. Switching power supplies are becoming popular because they offer better solutions to these problems.

Switching voltage regulation is the technique by which an unregulated source power is efficiently converted to regulated load power through the use of controlled power switching devices and energy transfer elements. DC to DC conversion is the heart of any switched mode power supply. There are many choices for DC to DC conversion but forward converter has dominated the market for the past 50 years for commercial power supplies in excess of 50W. At the beginning, this thesis describes the basic functional blocks of a switched mode power supply. Then the design of various elements that are generally used in any switched mode power supply is extensively covered. Later the theory and operating principles and limitations of a forward converter are discussed. Finally, the simulation results for a forward converter and test results on an engineering reference switched mode power supply are presented.