When developing your design in the Vivado tools or Vitis environment, you must ensure that your design is within the constraints of your power delivery and thermal solution, which is typically based on early power estimation as determined by the Power Design Manager (PDM) tool. It is extremely important to ensure your design is properly constrained, because changes to your power delivery and thermal solution can be costly.
At a minimum, Xilinx recommends applying the total power budget, maximum process, and worst-case junction temperature to create a worst-case power analysis, using the following XDC constraints:
set_operating_conditions -design_power_budget <Power in Watts>
set_operating_conditions -process maximum
set_operating_conditions -junction_temp <Max Tj based on Temp Grade>ΘJa = (Tj – Ta)/ Pd. Units are Celsius per
watt (°C/W).The most accurate power estimation can be achieved after the Theta Ja of the
thermal design is known. You can apply the Theta Ja and the maximum supported ambient
temperature (Ta) of the application to report_power using the following
constraints to replace the junction temperature setting. Using these constraints allows
report_power to estimate the junction temperature more accurately
and therefore, give a more accurate static power estimation.
set_operating_conditions -design_power_budget <Power in Watts>
set_operating_conditions -process maximum
set_operating_conditions -ambient_temp <Max Supported by Application>
set_operating_conditions -thetaja <Increase in Tj for every W dissipated C/W>In addition, you can specify the power delivery design using XDC constraints.
Using this approach allows report_power to report the margin on the
total power, check the power estimation on the power rails, and report the margin based
on the specified estimation and power rail consolidation. For more information on these
constraints, see the
Vivado
Design Suite User Guide: Power Analysis and Optimization
(UG907).
create_power_rail <power rail name> -power_sources {supply1, supply2 ,..}
add_to_power_rail <power rail name> -power_sources {supply1, supply2, ..}
set_operating_conditions -supply_current_budget {<supply rail name> <current budget in Amp>} -voltage {<supply rail name> <voltage>}