I would like to ask for some help in implementing short-circuit protection on outputs of a PCB. I have a PCB, which is powered with 12 V DC from an external PSU. This power line gets routed to PCB’s output connector in two ways: directly or through a relay controlled by one of the PCB’s processor. A simple diagram showing this is provided below.
The goal is to implement short circuit protection on all of the output connections in a way that when a short circuit occurs, the board does not reset itself but only the short circuited output is disconnected with automatic reconnection when the short-circuit is removed.
As it is now, a short-circuit causes the external PSU to activate its short circuit protection and powers down the whole board. After trying with resettable PTCs on each output, the situation improves slightly. The board goes down, the PTC disconnects and the board is powered back up even if the short circuit is not removed. My understanding is that the fuses are too slow compared to PSU's internal circuit protection.
The next option I am looking at are intelligent power switches (IPS), such as for example the L6375S or L6370. Not ideal though, since I would like of limit the current at max 1 A (those ICs have their output currents set at 0.5 and 2.5 A, with short circuit currents at 1.1 and 3.2 A). But it's a start.
Does anyone have any experience with IPS? Would they get the job done? Are there any other options you would recommend?
A big thanks to everyone for any ideas, comments or other input. Cheers!
p.s.: User can connect different loads to the outputs. While inductive loads are not expected, they can’t be completely ruled out. However, if ruling them out would lead to an elegant solution, I could probably live with that.