I've got a 24V incoming supply, and a need for a number of supplies (+12,
+5, -5, and +3.3). The +/- 5V supplies are for a bit of analog circuitry on a largely digital board, so they have low current requirements. My plan for the +5V supply is to just hang a 78xx05 off the +12V. +12V and +3.3V are going to come from switchers off of +24V.Anyone have any suggestions for a clever way to get -(something) from one of the positive supplies? I'm thinking that if I can get some negative voltage for cheap from one of the existing switchers that I can then regulate it to -5V with a 79xx05. I expect I'll end up using a charge pump -- but suggestions are welcome.