Question, anyone out there know how possibly to turn off the positive
    rail with an N-channel mosfet instead? This would be much better as
    typically N-channel have a much lower Ron.

Sure.  Look into "hot swap controllers", which are somewhat likely to
include appropriate gate drive boosters (Vg will need to be some volts
higher than your positive supply voltage to use N channel mosfets there.)  I
have in front of me a board from the dumpster with a whole bunch of LTC1641
chips on it, for instance.  This is aimed (I think) at hot swap of 48V telco
supplies, but the data sheets says it works for supplies down to 9V.  I'd be
surprised if there aren't similar low voltage solutions, especially with the
growing number of hot-swap technologies (ie USB.)  (like the LTC1422?)

BillW

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