I have seen it on one board. Funny thing is it does not always do it. Gerald
On Fri, Nov 14, 2014 at 11:45 AM, John Syn <[email protected]> wrote: > > From: Graham <[email protected]> > Reply-To: "[email protected]" <[email protected]> > Date: Friday, November 14, 2014 at 8:03 AM > To: "[email protected]" <[email protected]> > Subject: [beagleboard] Re: Labolatory power supply fails to power up > BeagleBone Black > > I have a similar problem, using a "B&K Precision 1550" Lab Bench Power > Supply. > When you turn on the Output of the supply, the BBB Power Light blinks once > and > the BeagleBone Black does not boot. > > If you put an oscilloscope on the output of the supply and watch it turn > on, then > the power supply overshoots up to 6 Volts, before returning to the 5 Volt > setting. > > That is just crazy. I have never seen a bench power supply do this. > Perhaps you should contact B&K, because there must be something wrong with > the voltage regulation on your power supply. > > Regards, > John > > > > It turns out that the Power Management IC used in the Beaglebone Black will > do an over-voltage shutdown at 6 Volts for protection. So, that is why it > does > one-blink then shuts-off. > > So, not only do you need a certain rise time, which the B&K power supply > meets, but you can not have any large overshoot. No good power supply > should have this much overshoot, but the B&K does, so it has problems > running a BBB. > > --- Graham > > == > > On Friday, November 14, 2014 4:03:37 AM UTC-6, bremenpl wrote: >> >> Hello there, >> I have a very strange problem with powering up BeagleBone Black (rev >> C).... When i try to power it up from some cheap AC adapter it works fine, >> but when I connect to to my labolatory power supply the power LED on board >> is lid for a second and then doesnt power up the MCU and turns off intead. >> I have connected both supplys to osciloscope and they are both stable, the >> laboratory one even more. Why is the power controller on the BeagleBone >> Black refusing to power up the MCU when powered from lab supply? I have no >> idea what is this about. I would aprichiate any help. >> > -- > 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 [email protected]. > 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 [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- Gerald [email protected] http://beagleboard.org/ http://circuitco.com/support/ -- 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
