USB short circuit on power - does it damage the PC?
When you want "inline" protection without much voltage drop, it is quite common to use p-MOSFET in place of diode. When power supply is connected correctly, internal diode in MOSFET will conduct and as soon as load voltage rises over MOSFET threshold, transistor opens and there is its "on" resistance only (no problem to get a part with down to tens of miliohm resistance with reasonable price and package). If someone inverts power supply, the internal diode is in reverse direction and gate voltage won't reach threshold (unpowered load => source terminal is at the same ground potential as gate).







simulate this circuit &ndash; Schematic created using CircuitLab

If your load has lot of capacitance, it would be wise to check that internal diode in the chosen transistor can handle inrush current and/or add external diode from drain to source.