Struggling finding good information, I would like to know which protections should be on a USB device ? The device is custom battery charger pcb (using MP2607 from MPS) which should be plugged on AC adapter (which will not be supplied with the device).
I guess it should have least ESD protection, but there shouldn't be any overvoltage, because it is not connected to the power grid.
If you have good links or good information, I would really appreciate