Re: [beagleboard] Re: Problem with 5V

[Graham Haddock]

Yes, try some other power supplies. and if they stay between 4.75 and 5.25
under all the different load conditions a BBB can create, it will work fine.

USB power is highly variable from computer to computer.  Sometimes it works
fine, sometimes it does not.
USB-1 was 0.5 Amps max, not enough to run a BBB, while booting or updating
the eMMC.
USB-2 is 0.9 Amps, about enough to handle the peak current from a BBB.
The Voltage limits for USB are 4.5 to 5.5 Volts. No margin if at the limits
under full load.

--- Graham

==



On Wed, Nov 8, 2017 at 12:35 PM,  wrote:

> thanks for the answer. i think i need to find other power and test with
> that. If that new one stays 4.75 - 5.25 it will working normally then?
> how about that, im thinking to run it with USB power via USB connector. is
> it ok?
>
>

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[beagleboard] Re: Problem with 5V

[Graham]

The one time flash means that the Power Management Integrated Circuit 
(PMIC) saw something about your power that it did not like and went into 
self-protect.

The 5 V power for the BBB must remain between 4.5 and 5.5 Volts at all 
times. even a transition out of that range for a millisecond or so will 
trip the self protect.
There are also some rise-time requiremetns when the power is turned on.

It is best to stay between 4.75 and 5.25, so that you have some margin, 
against the self-protect points.

Put an oscilloscope on your 5V power and figure out what is happening.

--- Graham

==

On Tuesday, November 7, 2017 at 12:41:47 PM UTC-6, Pekka R wrote:
>
>
> Hello.
>
> With 5V power, BBB not starting normally, only power led flashes 1 time. 
> And if i connect USB without 5V PSU it starting up. 
> Is there something broken or what? 
>

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