[BBB] How much current is supplied with 3.3V header pin?

[JeongHwan Kim]

Hi, everyone

I'm attaching the audio codec breakout board with BBB.

How much current is supplied with 3.3V header pin of BBB?

I wonder if BBB can supply current enough to the attached audio codec board.

Thanks in advance.

JeongHwan Kim

[Dennis Lee Bieber]

On Sun, 21 Mar 2021 07:29:27 -0700 (PDT), in
gmane.comp.hardware.beagleboard.user JeongHwan Kim

<frog007.kernel.kr-Re...@public.gmane.org> wrote:


>I'm attaching the audio codec breakout board with BBB.

A link to the documentation of said board would be useful -- I don't
know if there are multiple makers of boards that qualify as an "audio codec
breakout".

>How much current is supplied with 3.3V header pin of BBB?

How are you powering the BBB? Note that, if using the USB-2 interface,
the entire board is running from a 5V 500mA supply (if the source can
provide it). Using the barrel connector with a wall-wart supply can provide
around 2.5A. You would now have to check the documentation for the voltage
regulation chip on the BBB to find out how much gets passed through it...

Documentation for the PMIC indicate 1.2A available output powering the
entire board. The BBB SRM shows that it has four LDOs, two at 100mA and two
at 285mA (I'd guess at least one of those is providing the 3.3V outputs on
the connectors). The spec sheet for the PMIC (-C variant) says 400mA for
the those two LDOs

The SRM states the expansion board headers provide up to 250mA @ 3.3V
(I can't tell if that is shared by the two pins, or if each pin can supply
250mA for a total of 500mA). The VDD 5V can provide 1A.

This is as much research as I'm willing to put in... All the documents
are available on-line (well, maybe the PMIC is blocked depending upon one's
country -- TI is weird that way).


--
Dennis L Bieber

[JeongHwan Kim]

Thank you for reply.

I'm using USB2 interface for powering BBB.

The codec which I mentioned is WM8731 (https://www.cirrus.com/products/wm8731/)

I'm using MikroElectronika breakout board (https://www.mikroe.com/audio-codec-proto-board)

2021년 3월 22일 월요일 오전 1시 56분 1초 UTC+9에 Dennis Bieber님이 작성:

[Dennis Lee Bieber]

On Sun, 21 Mar 2021 20:58:18 -0700 (PDT), in

gmane.comp.hardware.beagleboard.user JeongHwan Kim
<frog007.kernel.kr-Re...@public.gmane.org> wrote:

>
>I'm using USB2 interface for powering BBB.

Which, for a compliant USB2 socket, provides a maximum of 500mA. Most
of that is used by the SoC and support (I think I read that the peak during
boot is around 400mA), so the amount available on the 3.3V pins will likely
be less than the 250mA (which should be available if using a 5V barrel jack
power supply). The main 5V pins are disabled under USB power.



--
Dennis L Bieber