Beaglebone Black power supply question (from an IC noob):

Beaglebone Black power supply question (from an IC noob):
I have an old power supply that’s labelled with output of 5V and 2.5A.
Will this work for a BBB?

I see in the BBB System Reference Manual where it says, “The board requires a regulated 5VDC +/-.25V supply at 1A. A higher current rating may be needed if capes are plugged into the expansion headers.”

How do we determine how much current is too much?

I too am extremely interested in the answer.

@Bernard_Roth what am I looking at? Nothing on that page seems to references the amperage limit for the BBB.

Max is 20v and 3000 mA

Is that for the BBB or just the TI stuff on the BBB?

The BBB uses a TPS65217. It’s in the BBB Reference Manual.

The current rating is a minimum. The voltage range is absolute maximum/minimum.

@Bernard_Roth The tps65217c is 20V tolerant, but I don’t think it will actually operate under those conditions.

A higher current rating on the DC supply is fine. In fact if you plan to use capes you will need more current. The board consumes the current it needs. Having excess available will not cause any issues.

@Gerald_Coley I was just going to ask about the board pulling just what it needs, thank you so much!

So this means that my 5v 10A power adapter will be just fine?

It should be. Make sure the voltage is within spec. After you plug it in check the voltage. Sometimes supplies that large have a minimum current to maintain regulation and the board only tales about .5A.

you have problems when you exceed the Amperage output rating of the adapter. if you do not exceed the output rating of the adapter, it should work just fine.

The voltage output of the adapter must match the device you are going to power; do not plug a 20 Volt adapter into a 5 volt appliance.

Thanks very much for the excellent help, everyone!

if the old beaglebone white is anything to go by (mine has seen a lot of abuse), it will just shut down if more current than supplied is asked for, but not be damaged or anything.

Volts are push, amps are pull. Don’t people learn anything in school these days?

If the power supply has a lot of current, more than a few amps, I would have a fuse. I would hate to have an accident and blow a bunch of traces on the circuit board.

Unless you do something to the board to cause a short like maybe pouring water or melted solder over it, this will not happen. The PMIC shuts down and limits the current.