This power supply design is for my course on Udemy -- Crash Course Electronics and PCB Design. Every month, I create a "bonus" lecture on varied subjects; anything from retro computing to AI. This month I decided to design a simple solderless breadboard power supply since all the units on amazon are so poorly designed. This is a good example of robust design within a budget. Addtionally, it addresses the problem that few newbies realize about USB power supplies, and that is a USB port typically puts out from 4.5-4.7V, RARELY will you get 5V at the USB connector, especially under load.
Thus, not only will a 5V linear regulator NOT work, simply connecting the USB VBUS to your 5V supply is a very bad idea since its typically poorly regulated, noisy, and not 5.0V. Therefore, this design features a boost/buck converter to make certain the 5V supply IS 5V regardless of how low (or high) the input is.
Please check the course out at: https://www.udemy.com/crash-course-electronics-and-pcb-design