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5,949 Views
Registered: ‎11-23-2016

Maximum power-on current Virtex-5 (f.e. XC5VFX130T)

Hello!

I want to use the XC5VFX130T in my experiment, but in datasheet and all internet (!!!) i could not find information about maximum power-on current.

But there i found minimum power-on current (see the picture). It is useful information, but not full for me. I need to know maximum current too!

 

And I want to know how the current changes when the chip is power-on. Can I submit a chip in the form of constant resistance through the power-on process?

 

Thank you very much!
From your answer depends on which sources power I choose. And my well-being! :)

 

Снимок.PNG
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Registered: ‎07-23-2015

@maestro_xil12 You need to use Xilinx Power Estimator tool (XPE) if you don't have the RTL. If you have the RTL, you can use ISE Power Analyzer. 

 

I would suggest going through below tutorials

 

XPE:  https://www.xilinx.com/products/technology/power/xpe.html

          http://www.xilinx.com/support/documentation/sw_manuals/xilinx14_7/ug440-xilinx-power-estimator.pdf

          http://www.xilinx.com/video/hardware/using-the-xilinx-power-estimator.html

 

XPA:  https://www.xilinx.com/support/documentation/sw_manuals/xilinx14_7/isehelp_start.htm#xpa_c_overview.htm

- Giri
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Registered: ‎11-23-2016

Thank you. I know about this.

But you do not understand my question. I want to know the maximum power-on  (not minimum!) current.

XPE can tell me about static current, but not about maximum power-on curent! Or i am not corect?

Help me, please! Thank you.

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Registered: ‎11-23-2016

Hmmm.

I took advantage of the program XPE and noticed that when using the process of "Maximum" currents are painted in blue only for Vcco and Vccaux. At the core voltage not release happen? Why is that?

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Registered: ‎07-23-2015

XPE is meant to calculate the Total On Chip Power of your device for the resources you use. 

 

Regd. Blue, if power-on supply current values exceed the estimated operating current requirements the cell will turn blue. 

- Giri
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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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Registered: ‎11-23-2016

Sorry for my stupidity, but still I have not received an answer to the question.
I'm looking for a current versus voltage when switched on (like a picture). Can you give me this information? At what voltage current begins to flow? 300mv or what? Many thanks!

 

u6jju.png
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Registered: ‎07-23-2015

@maestro_xil12 You initially mentioned requiring maximum current "I want to know the maximum power-on  (not minimum!) current." which is what the XPE will help you. 

 

Regarding the current vs voltage graph, don't think there is that data available. But why do you need that? 

 

Once you input all the logic you plan to use in XPE and have the process set to Maximum, the tool gives out the worst case Current consumption of each rail. Design your board based on those values and you should be good to go. 

- Giri
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Keep conversing, give Kudos and Accept Solution when you get one.
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Registered: ‎11-23-2016

Thank you!

I need to know current vs voltage graph because i want to make a power supply for XC5VFX130T.

OK, one more question: at what voltage FPGA begins to pass current? At 300 mv or not?

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Registered: ‎07-23-2015

@maestro_xil12  i want to make a power supply for XC5VFX130T.

 

Use the value from XPE as the Maximum Power Consumption and check the current consumption for each rails and desing you Power supply by choosing Power regulators with some margin. 

 

For e.g. if XPE reports your VCCINT Power rail to draw 6A (With Process:Maximum), use a regulator that can supply 8A to account for worst case scenario. 

 

The moment you power on the FPGA, it starts consuming power i.e. drawing current. Once you start configuring additional current will be required once the buffers are powered on and your FPGA is functional. 

- Giri
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Registered: ‎01-08-2012


@gnarahar wrote:

 

Once you input all the logic you plan to use in XPE and have the process set to Maximum, the tool gives out the worst case Current consumption of each rail. Design your board based on those values and you should be good to go. 


 

I wish that were true.

See (e.g.) AR#59294 for a counter-example.

 

Perhaps it would be more correct to say that "[XPE] gives out the worst case average Current consumption of each rail in the steady state, with the supply voltages in the recommended range."

 

 

On a test board of mine I measured (short term) transceiver currents of about twice the maximum given by XPE.

This was a problem at the time, because I had designed the PSU to limit current to about twice the value given by XPE.  Sometimes it would pull that rail down and reset the whole board (which would then get stuck in a loop: overcurrent -> rail collapse -> reset -> rail recovery -> boot -> program FPGA -> overcurrent).

In that particular case the problem was solved by taking the transceivers out of reset one at a time, which limited the peak current to a safe value.

 

Allan

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