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Observer
Observer
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Registered: ‎07-15-2015

KC705 & KC105 maximum current on 3.3V

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Hello,

I'm using the KC705 Evaluation Board in combination with two XM105 debug cards.
I want to power some other hardware through the J16/1 & J16/2 pins of the dabug cards over a longer period.
I am planning to set the HDR_POWER of one card to 2.5V and the HDR_POWER of the other to 3.3V to have one 2.5V and one 3.3V supply.

I'm worrying what is the maximum current I can get out of the J16/1 & J16/2 pins then? (I think the current needed, will be in the range of some hundred mA)


In UG810 figure 1-35 it is written that the VCC3V3 is powered by a switching regulator (U103) which provides up to 10A.
That means I could get up to 10A from the J16/1 & J16/2 pins on the debug card, do I understand that correctly? Or is there a limitation through the debug card(I don't need as much, I just would like to know the approximate limit.

In a thread about another board (SP605) I read, it is capable of providing 3A through 3.3V.
(https://forums.xilinx.com/t5/Xilinx-Boards-and-Kits/SP605-board-FMC-3-3v-shutdown/td-p/250476)
So I guess I'll be on the safe side if I assume up to 2A is no big deal for my board?


Thank you in advance,
asteric

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Moderator
Moderator
13,710 Views
Registered: ‎07-23-2015

Re: KC705 & KC105 maximum current on 3.3V

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@asteric_ The J16 are Through hole headers and they have good current carrying capability going into few Amps. You are OK for the "hundreds of mA" you intend to drive. 

 

That means I could get up to 10A from the J16/1 & J16/2 pins on the debug card, do I understand that correctly? 

 

No. The 3V3 regualtor powers various other devices on KC705 board as well. Check the KC705 Schematic for details. 

 

 

- Giri
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Moderator
Moderator
13,711 Views
Registered: ‎07-23-2015

Re: KC705 & KC105 maximum current on 3.3V

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@asteric_ The J16 are Through hole headers and they have good current carrying capability going into few Amps. You are OK for the "hundreds of mA" you intend to drive. 

 

That means I could get up to 10A from the J16/1 & J16/2 pins on the debug card, do I understand that correctly? 

 

No. The 3V3 regualtor powers various other devices on KC705 board as well. Check the KC705 Schematic for details. 

 

 

- Giri
--------------------------------------------------------------------------------------------------------------------
There's no such thing as a stupid question. Feel free to ask but do a quick search to make sure it ain't already answered.
Keep conversing, give Kudos and Accept Solution when you get one.
-----------------------------------------------------------------------------------------------------------------------

View solution in original post

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Observer
Observer
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Registered: ‎07-15-2015

Re: KC705 & KC105 maximum current on 3.3V

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Thank you for the information.

 

That makes sense. The manual and schematics say quite a lot of components are connected to VCC3V3 (SD card, HDMI, JTAG, SFP+, ...), but not how much current they need or can be used by myself. (At least I cannot find this information. Is this based on experience?)

The VCC5V0 power regulator (2A max) on the other hand seems not to power as many devices. (I'm not using an LCD)

Would it also be possible to get 500mA from the VCC5V0 instead of the VCC3V3?
The schematic is a good hint for an overview, but I don't really get numbers out of it.

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Moderator
Moderator
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Registered: ‎07-23-2015

Re: KC705 & KC105 maximum current on 3.3V

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@asteric_ Not sure if I understand you right. How do you plan to get VCC5V0 on your XM105 boards?

- Giri
--------------------------------------------------------------------------------------------------------------------
There's no such thing as a stupid question. Feel free to ask but do a quick search to make sure it ain't already answered.
Keep conversing, give Kudos and Accept Solution when you get one.
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