The design of a switching power supply has always been considered a kind of magic and art, for all the engineers that design one for the first time.
Fortunately, today the market offers different tools that help the designers. National Semiconductor was the first company to offer the “Simple Switcher” software, and an on-line simulation tool that allows the design and simulation of a switching power supply. New ultra-fast MOSFETs and synchronous high switching frequency PWM controllers allow the realization of high efficient and smaller switching power supply.
All these advantages can be lost if the input filter is not properly designed. An oversized input filter can unnecessarily add cost, volume and compromise the final performance of the system.