The design I am working on is having peripheral connector with +5V power in it providing the voltage to the would-be connected device. There's relatively a long way inside the design from the ATX power supply to the connector, with edge connector involved in between.
I am thinking about building some kind of simple protection from the shortage or overcurrent. The ATX PSU can provide enormous amperage, thus it could be a reality that something happening after the peripheral connector will fry the power lines on the way from the ATX power supply.
I know about several ways:
- fuse. It will blow on overcurrent, and will need to be replaced. For the design, it is not a big issue as it is assumed that owner is able to maintain/repair it;
- polyfuse (MF-MSMF020 or MF-R020). A kind of multi-fuse, while being convenient has several drawbacks. It seems its "protection time" is larger than of fuse; it heats so that there must be no parts around damaged by the heat (e.g. plastics), and if too much stressed, can eventually increase the resistance, as well as having higher initial resistance than fuse;
- some electronic protection circuit.
I want to be as simple as possible; and it is ok if fuse is blown and needs to be replaced on the overcurrent event which would be considered as exception rather than a rule.
Thus the answer may be obvious - use 250 mA fuse, ideally socketed. Maybe like this on the Symbios SCSI card.
I can not find part number for such fuse.
And is there any other better way/device to achieve the protection from the external overload?