Page 1 of 1

USB Power Output

Posted: 26 Jul 2018, 21:23
by timjones
What is the maximum USB Power output for the 2 ports? I am trying to drive an 7" LCD display and having the power off of the USB port it only flickers.

Re: USB Power Output

Posted: 27 Jul 2018, 06:23
by volker
If you want to operate the waveshare 7" on a RevPi Core 3 you need to use an external powered USB hub because we have restricted the USB ports of a RevPi Core 3 to the 500 mA maximum current defined by USB norm.
On a RevPi Connect you can draw up to 1 A from a single USB port but only 1 A in sum for both USB ports together (this is a violation of the USB norm but we've recognized that many vendors are violating the rule, e.g. waveshare or several GSM stick vendors). Please note that you could have simply answered your question by looking on the side printing of the case or the spec sheet ("Shop" or "Project" section). We have limited resources to run this forum and thus I would kindly ask you to search such information on these resources before posting in the forum.

Re: USB Power Output

Posted: 27 Jul 2018, 16:01
by timjones
Thanks! Is there any plans of releasing the schematic for the RevPi Connect?

Re: USB Power Output

Posted: 27 Jul 2018, 22:53
by volker
They will be published. Please give us some time for preparing them for the web.

Re: USB Power Output

Posted: 30 Oct 2024, 17:21
by hakaies
Can someone confirm the USB power output for a REVPI CORE SE+ 32GB 100367

Thank you.

Re: USB Power Output

Posted: 31 Oct 2024, 21:03
by nicolaiB
Hi

You can find these information in our datasheet (eg https://revolutionpi.com/wp-content/upl ... ore-SE.pdf)
2 x USB A (total current draw from both sockets together max. 900 mA)
900 mA USB output current (sum of both USB outputs) is only available with input voltages >11 V. The bridging time of voltage
dips of at least 10 ms required by EN 61131- 2 is only guaranteed with a supply voltage of 20.4… 28.8 V. At 12 V input voltage
this time decreases drastically, especially when driving loads by USB ports
Hope this helps,

Nicolai