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C6678 Power spreadsheet (1.25GHz Vs. 1.0GHz)

NK49690
Prodigy 200 points

Hi,

We are using "C6678_Power_Consumption_Summary_Rev1_0_3.xlsm" to estimate power needed.

We notice that with same parameters there is about 70% increase in Core power (CVDD) when Core frequency increases from 1.0GHz to 1.25GHz.

We notice that with same parameters there is about 18% increase in Core power (CVDD) when Core frequency increases from 0.8GHz to 1.0GHz.

Is this normal? Is there a problem in the spreadsheet?

Please see below:

800MHz:

1000MHz:

1250MHz:

  • 0
    TI__Mastermind 30825 points

    The numbers in the power spreadsheet are correct.  There's a significant shift in leakage current (part of the baseline power numbers to achieve the 1.25GHz speed of operation do to the need to bias the voltage level a higher to achieve the performance required.)

    That said, the CorePac CVDD Activity numbers you have (443 and 848mW) for the cores looks like it may have come from a combination of 80% SP and 20% CC, which is not a realistic scenario.  Very few kernels achieve 8 operations per cycle and you're suggesting it's operating at this 80% of the time.  A more realistic scenario is about 27-30% SP for a very Signal Processing Intensive code.

    Best Regards,

    Chad

  • 0 in reply to Chad Courtney
    Prodigy 200 points

    Hi Chad,

    Thank you for your reply!

    We have changed the scenario to 30% SP 60% CC as shown below.

    1. However; in all cases we notice that power consumption for DVDD18 of the DSP is only 34mW. Is this all needed from 1.8V supply to DSP?

    2. There is no parameter to select if we use one or two SGMII ports. How is this shown and calculated in the spreadsheet?

    3. There is no parameter to select if we use one or two PCIe Lanes. How is this shown and calculated in the spreadsheet?

    Thank you and best regards,

    Naseeb

  • 0 in reply to NK49690
    TI__Mastermind 30825 points

    It looks like items that use the 1.8V Supply (I2C, UART, SPI, EMIF16) you have disabled, so there's just the baseline clocking power associated with it.

    For PCIe assume if you're using 1 lane @ 100% that it's a total of 50% utilization, for SGMII for 1 port @ 100% it's 50% total utilization.

    Best Regards,

    Chad

  • 0 in reply to Chad Courtney
    Prodigy 200 points

    Thank you Chad!