Switch Mode Power Supplies

For many years prior to the 1970s, engineers designed and built switch mode power supplies (SMPSs) using methods based largely on intuitive and exper- imentally derived techniques. In general, these power supplies were able to achieve their primary goal of high-efficiency power conversion; unfortu- nately, due to the lack of adequate theoretical analysis techniques, many of these power supplies only marginally met their desired performance require- ments. In many cases, they were considered to be unreliable.