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1V Power supply under-powered

Former Member

What's the maximum power that can by drawn by the Zynq PL? Has this been tested?

I have build a large design (80%) that need to runs at 100MHz, but when I program the bitstream to the Zedboard. The Zynq reset a few ms after being DONE.

Also, I have probed the 1V power supply at C357. After, the PL is DONE, the voltage go down to about 560mV and go back up to 1V probably because the PL resets.

What could be causing this?

Is it because the PL draw to much power?

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  • 0

    I though I'd let you know that I have confirmed this issue.

    I bypassed the 1V power supply by using an external power supply. Now, the design is working and as much as 3A is drawn from the 1V power supply.

    This is much more than the 2A the MAX15021ATI+ (onboard 1V PSU) is capable of.

  • 0 in reply to Former Member

    You are correct that the 1V supply on ZedBoard has a max capacity of 2A. This is shared between all of the 1V requirements on Zynq 7020 -- Vccint, Vccpint, and Vccbram. We estimated what a reasonably aggressive design might do using the tools available at the time which was 13.2 Beta Xilinx Power Estimator. We then added 50% margin to cover any inaccuracies.

     

    It is unfortunate that ZedBoard is not capable of supplying what your application requires. If you are willing, I am very interested in correlating what we created in XPE to what your design is doing. Have you analyzed what your design should be drawing in XPE? If so, will you please share it?

     

    As changing the 1V supply on ZedBoard would require extensive redesign and we believe it is sufficient for the majority of users, we will not redesign the ZedBoard power supplies.  For those that need more than 2A on the 1V rail, we recommend you use the ZC702 board instead.

     

    Bryan

  • 0 in reply to bhfletcher

    Xilinx Power Analyzer calculates that my design will use around 1.2A ( http://www.louif.com/power_analysis.png ). I think this is not considering what the ARM processor is using (0.6A).

    So, I cannot account for up to 1.2A of power usage. Also, 3A is a peak usage, so it may have been transcient.

  • 0 in reply to Former Member

    I would agree that this screenshot does not include show the PS running -- notice the Vccp___ supplies. Vccpint is only drawing 23 mA. So there is definitely something missing here. Assuming the PS is 0.6A, that extra 1.2A is still a mystery. We have re-analyzed a Zynq 7020 design in the latest 2013.1 XPE with a 80-90% loaded design, and we are still getting ~1.2A, including the PS. I have never known XPE to be more than 20% off. Perhaps we are not including something. Or maybe XPE has a bug this time. Perhaps your design has characteristics that we haven't mapped properly in XPE, such as clock rate, fanout, etc.

     

    If you'd like to take a look at our analysis, see the XPE spreadsheet here.

    7_Series_XPE_2013_1_ZedBoard_130610.xlsm
    https://avnet.egnyte.com/h-s/20130611/67cc6ff8db144e92

     

    Bryan

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  • 0 in reply to Former Member

    I would agree that this screenshot does not include show the PS running -- notice the Vccp___ supplies. Vccpint is only drawing 23 mA. So there is definitely something missing here. Assuming the PS is 0.6A, that extra 1.2A is still a mystery. We have re-analyzed a Zynq 7020 design in the latest 2013.1 XPE with a 80-90% loaded design, and we are still getting ~1.2A, including the PS. I have never known XPE to be more than 20% off. Perhaps we are not including something. Or maybe XPE has a bug this time. Perhaps your design has characteristics that we haven't mapped properly in XPE, such as clock rate, fanout, etc.

     

    If you'd like to take a look at our analysis, see the XPE spreadsheet here.

    7_Series_XPE_2013_1_ZedBoard_130610.xlsm
    https://avnet.egnyte.com/h-s/20130611/67cc6ff8db144e92

     

    Bryan

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