hippy
Posts: 10967
Joined: Fri Sep 09, 2011 10:34 pm
Location: UK

Pi Zero - Power supply fuse

Thu Nov 26, 2015 9:30 am

Does the Pi Zero have a resettable fuse on-board, and if so; what is it rating / how much current can be drawn out of the USB socket ?

I imagine a lot of the circuitry can be deduced from what has already been published for other Pi models but I'll ask anyway; will there be a full circuit diagram released ?

drgeoff
Posts: 12420
Joined: Wed Jan 25, 2012 6:39 pm

Re: Pi Zero - Power supply fuse

Thu Nov 26, 2015 11:17 am

Pi Zero is not universally known nomenclature. What do you mean?

All RPis have a self-healing fuse on the microUSB power input. The very first RPis had additional such fuses in the power feeds to the two USB ports. These limited the current to around 100mA; enough for a keyboard or mouse but not a USB powered hard drive or Wi-Fi dongle.
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PhilE
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Location: Cambridge

Re: Pi Zero - Power supply fuse

Thu Nov 26, 2015 11:18 am


ame
Posts: 3902
Joined: Sat Aug 18, 2012 1:21 am
Location: New Zealand

Re: Pi Zero - Power supply fuse

Thu Nov 26, 2015 11:50 am

drgeoff wrote:Pi Zero is not universally known nomenclature. What do you mean?

All RPis have a self-healing fuse on the microUSB power input. The very first RPis had additional such fuses in the power feeds to the two USB ports. These limited the current to around 100mA; enough for a keyboard or mouse but not a USB powered hard drive or Wi-Fi dongle.
You must be new here.
Hmm. What can I put here?

drgeoff
Posts: 12420
Joined: Wed Jan 25, 2012 6:39 pm

Re: Pi Zero - Power supply fuse

Thu Nov 26, 2015 1:20 pm

Aha!

Since my previous post, I've been out to buy a copy of MagPi with PiZero stuck on the front cover.

The component below the D and M in HDMI looks like a polyfuse.
Quis custodiet ipsos custodes?

drgeoff
Posts: 12420
Joined: Wed Jan 25, 2012 6:39 pm

Re: Pi Zero - Power supply fuse

Thu Nov 26, 2015 2:39 pm

I'm wrong again. That is a diode.

Enough mistakes for one day. :(
Quis custodiet ipsos custodes?

hippy
Posts: 10967
Joined: Fri Sep 09, 2011 10:34 pm
Location: UK

Re: Pi Zero - Power supply fuse

Thu Nov 26, 2015 2:54 pm

This was one of the best images of the board a quick Google search turned up ...

http://media.gizmodo.co.uk/wp-content/u ... -zero1.jpg

Components on one side only. No "F1" or other "F" component I could see so I would expect it has been left out for the sake of cost.

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