It will not protect against reverse polarity.A full wave rectifier will cause a voltage drop and then you o longer have 5V. Yes I could have added some reverse protection, but I must admit out of 200,00 boards shipped I have sen about 10 cases of reverse polarity. So adding he cost to all boards for that feature does not make a lot of sense. I removed the NCP349 on the BBB..Out of the 150,000 of those shipped, I think we maybe had 3 cases of reverse polarity.
Gerald On Thu, May 22, 2014 at 2:15 AM, Eric Fort <eric.f...@gmail.com> wrote: > are you saying that the ncp349 *CONTAINS* a full wave bridge rectifier? I > certainly didn't see that in the data sheet. Note the point is protection > from overvoltage and possibly, thus the question, polarity reversal which > may or may not be the same as severe under voltage. > > Eric > > > On Wed, May 21, 2014 at 11:18 PM, Bayani Custodio < > bayani.p.custo...@gmail.com> wrote: > >> Full wave bridge rectifier, if they make 'me small enough would be the >> cat's meow. Worked we'll on an old project back in the op amp days. >> >> Sent from my iPad >> >> On May 21, 2014, at 11:41 PM, Eric Fort <eric.f...@gmail.com> wrote: >> >> the ncp349 chip used for overvoltage protection on the dc power input for >> the beaglebone seems to do a good job of providing overvoltage protection. >> Even looking at it's datasheet though, I'm not completely sure if it will >> protect the board against reverse polarity. (I'm not out to overtly or >> purposely try this but I too have occasionally made mistakes...) >> >> so should the beagle bone white/black be protected from application of >> reverse polarity being applied, i.e. powering it with -5v instead of +5v, >> by the ncp349 (or might it be a good idea to add a reverse polarity diode >> across DC in that will pop the power supply & save the board. >> >> Eric >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to beagleboard+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to beagleboard+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to beagleboard+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
