jfgist
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Simple Power Question (Passing Power to Peripherals)

Thu Oct 31, 2013 3:59 pm

I've been doing some searching but there is a lot of information to weed through and I can't get a clear answer.

For the Rev2 boards (both models)...If my power supply can provide enough current to power peripherals will the RPi pass it through the onboard USB ports.

For example, I have some USB speakers that could draw up to 1A, the Model B could draw up to 700mA. If I have a 2A or 3A supply will I be able to power the speakers directly from the Pi?

I'm not interested in powering over the GPIO pins and I would like to avoid a powered hub to save space.

Thanks

ShiftPlusOne
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Re: Simple Power Question (Passing Power to Peripherals)

Thu Oct 31, 2013 6:48 pm

No, the pi power input has a polyfuse that will prevent this from happening.

Dilligaf
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Re: Simple Power Question (Passing Power to Peripherals)

Thu Oct 31, 2013 6:52 pm

I know you said you're not interested but over the gpio it will work, from the micro usb you're still limited by the input fuse, unless you replace it with a larger fuse or jump it.

jfgist
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Re: Simple Power Question (Passing Power to Peripherals)

Thu Oct 31, 2013 7:08 pm

Ahh, I see that now in the schematic.

I am thinking my best bet would be to use a Model A (that's only going to draw 300mA) and I should still have ~800mA to power peripherals.
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jfgist
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Re: Simple Power Question (Passing Power to Peripherals)

Thu Oct 31, 2013 7:10 pm

Dilligaf wrote:I know you said you're not interested but over the gpio it will work, from the micro usb you're still limited by the input fuse, unless you replace it with a larger fuse or jump it.
Now that I am getting a better understanding...

I guess my concern with going through the GPIO is that I would lose that fuse protection.

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mahjongg
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Re: Simple Power Question (Passing Power to Peripherals)

Thu Oct 31, 2013 10:33 pm

jfgist wrote:I guess my concern with going through the GPIO is that I would lose that fuse protection.
yes, unless of course you add your own polyfuse with a higher rating.

Dilligaf
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Re: Simple Power Question (Passing Power to Peripherals)

Thu Oct 31, 2013 10:49 pm

Just put an inline fuse in the wiring to the gpio

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Tage
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Re: Simple Power Question (Passing Power to Peripherals)

Fri Nov 01, 2013 1:26 am

just replace the polyfuse with a piece of wire. and make sure you have a quality 5V power supply that makes the polyfuse not necessary.

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