On Thu, Nov 14, 2013 at 2:28 PM, Derek dlahouss@mtu.edu wrote:
Christopher Thomas <christopher <at> firemothindustries.com> writes:
PYB20-Q24-S5 is an isolated supply that will output 5V at 4A. But that digikey pricing suggests their not economical
yet.http://www.digikey.com/product-search/en/power-supplies-board-mount/dc-dc-co...
While not the best for the job, it's certainly appealing at .22c versus
$39.
the current solution i've put in is around the $1, $1.50 mark. however as christopher points out and looking at the datasheet the thermal characteristics may be um.... well, you'd better have a metal heat sink basically. so buck converter it's more likely to be.
But taps out at 3A. if there's a way to cull some wattage from the 20w point.
nope. 2x 5V USBs (0.5A rated each) so that's 5W, 2x 3.3V USBs (over-current because they're MiniPCIe cards - some of the 3G MiniPCIe boards draw 0.7A) so that's still 2.5W each x 2 making 10W. the RTL81366 is 3W because it's 5-port Gigabit - we're lucky it's even as low as 3W. and the CPU Card is going to be around 4 (any more is pushing it).
10+3+4 = 17.
so... 5V * 3A = 15W is not enough.
What about running the voltage regulators in parallel? 2 * 3A = 5.5A, or so.
maybe... except if it's double the cost of the components to do the same job, why would you do that? :)
http://electronicdesign.com/power/double-your-output-current-parallel-voltag...
will take a look this evening.
l.