usb current B+

[steave]

I need to connect an internet key on usb.
the currents are compatible?
by testing everything is ok.
HW is sized well. can I be sure?

thanks

[drgeoff]

What is an "internet key"?

And even when we know what you mean by such a generic term it will probably be helpful if you tell us the specific make and model number.

[steave]

example:
http://consumer.huawei.com/it/mobile-br ... /index.htm


now, i'm testing with huawei k3765, hspa usb stick


the problem is not the kind of intenet key (or whatever you want to call it) but his current consumption.
nb.
the current consumption varies according to the status of connection on the network umts

How can supply B + with security?
I can't find the scheme portion of usb.

thanks

[fruitoftheloom]

If you have a 5V2A PSU you can increase the USB Current from 600ma to 1200ma

https://projects.drogon.net/testing-set ... berry-pi-b

In config.txt add:

Code: Select all

max_usb_current=1

[steave]

thank you.
if you need an external power supply,
1- can i feed B+ from + 5V connector gpio and micro usb disconnected ?
I tried.
I noticed that for a moment the red light goes off, during startup.
there are contraindications?

2- you tell me where I can find the whole scheme of B +, so i understand how it works
Thanks again

[Burngate]

The full schematic of the B+ hasn't been published.
However, from https://www.raspberrypi.org/documentati ... /README.md
and data-sheets for the 9514 USB chip and the AP2553 power-control chip, it's possible to make an educated guess as to what's going on.
I did exactly that, almost a year ago. Since I can't find my original post, here's a copy.

USBpower-B+.png

[Burngate]

Not sure why the picture isn't appearing; I'll try again.

USBpower-B+.png (5.39 KiB) Viewed 1820 times

[steave]

ok. thanks.

are there problems if the power of B + is given (+5v, 2,4 pin) in gpio and not by micro usb? There are limitations to the maximum current hw? eg. size tracks etc ..