TABLE OF CONTENTS Throughout the early years in my career of designing switching power supplies, I always accumulated a small pile of power transistors on the bench while I was evaluating my power supply designs. I had developed a saying: "If you don't stick your fingers inside the circuit, you won't break it". Unfortunately, you always have to "stick your finger in". So order a lot more power transistors and other semiconductors than you think you need.
The semiconductors are the most fragile components within any switching power supply. Applying them correctly will make them operate reliably over all of the operating conditions of the system. They also have a direct effect on the overall supply.
Kularatna overviews all of the major power switches and rectifiers used in the switching power supply field today, some of which will not be used by the majority of power supply designers except in the very high power market (over a kilowatt). He summarizes each of the semiconductor's advantages and weaknesses.
Marty Brown
During the elapsed half century since the invention of the transistor, the power electronics world has been able to enjoy the benefit of many different types of power semiconductor devices. These devices are able to handle voltages from a few volts to several kilovolts and switching currents from a few milliamperes to kiloamperes. Within a decade from the invention of the transistor, the thyristor was commercialized.
Around 1968 power transistors began replacing the thyristors in switchmode power systems. The...
