This is a simple buck converter with an output of 5v 4A for an input between 5v and 15v.

The board also has a polarity inversion protection, over tension and over current / short circuit protection tested with laboratory equipment.

The efficiency seems to be around 75%, that may lead to an overheating in case of high intensity output. MAke sure yours is cooled enough.

This PCB was made tiny so I could test it in the worst conditions but I highly recommend making it wider.

You can also change a few components to make the PCB cheaper. Especially the 47uH inductance which can be replaced by a bigger through hole one making it cheaper.

Some pins here are only for test purposes, and yoou also can change some resistors to adjust the output volatge following the formula : Vout = Vf ( 1 + R2/R1) where Vf = 1.23V .

There's also some curves made with easyeda simulation mode to make sure the protections I made would work. These aren't only designed for the converter but also to other devices using the input. Maybe some improvments should be made there but keep in mind this module is for consumer electronics only.

Have fun with my work !