It can take significant time and effort to properly design a power supply, calculate component values, and select active and passive components that fit. The process can become very time-consuming as a designer iterates component value calculation and type selection in order to choose the best discrete components for the required design criteria. A typical design criterion includes efficiency, the size of the design, and the overall solution cost.
Most often you won’t know if you’ll meet the design specifications until the component-level design process is complete. Using design calculations and/or simulation tools, you can determine if you’ve either realized the design target specifications or not. If not, you’ll need to go back and virtually restart the process with new components. This is very time-consuming when done by hand, taking hours or days of complex work.