When reviewing the total static power at maximum process, I see that the power supply summary does not add up to the total on-chip power.
Why are they different?
The device static power summary, at maximum process, does not match the sum of the Power supply current summary in XPE 2015.2 and beyond.
The worse case total device static power, at maximum process, is reported under Total On-Chip Power Summary per power supply source row on the summary tab.
The UltraScale devices operate within the maximum static power specification. There is a per rail current specification associated with the worse case device static power, which is reported under Power Supply summary.
The maximum static current of each supply rail is tuned during the manufacturing process to achieve maximum yield benefit. This results in a variations up to 10% per supply rail current.
In some cases, the current of one rail can increase, while another rail decreases to compensate, and the total device static power will be within the worse case power estimation in the total static on-chip power value.
This feature in XPE helps you to design a power supply system with enough headroom to handle any manufacturing process variation in a given device.
We do not recommend manually calculating the device static current from the supply current fields to compute the actual design static power.