XPower Overview

XPower provides power and thermal estimates after PAR, for FPGA designs, and after CPLDfit, for CPLD designs. XPower does the following:

Estimates how much power the design will consume
Identifies how much power each net or logic element in the design is consuming
Verifies that junction temperature limits are not exceeded

Files Used by XPower

XPower uses the following file types:

CXT - File produced by CPLDfit and used by XPower to calculate and display power consumption.
NCD - An physical design file produced by MAP and PAR that contains information on an FPGA. Xilinx recommends using a fully placed and routed NCD design (produced by PAR) to get the most accurate power estimate. Using a mapped-only NCD (produced by MAP) file may compromise accuracy.
PCF - An optional user-modifiable ASCII Physical Constraints File (PCF) produced by MAP. The PCF contains timing constraints that XPower uses to identify clock nets (by using the period constraint) and GSRs (by looking at TIGs). Temperature and voltage information is also available if these constraints have been set in the User Constraints FIle (UCF).

Note: The Innoveda CAE tools create a file with a .pcf extension when generating a plot of an Innoveda schematic. This PCF is not related to a Xilinx PCF. Because XPower automatically reads a PCF with the same root name as your design file, make sure your directory does not contain an Innoveda PCF with the same root name as your NCD file.

VCD - Output file from simulators. XPower uses this file to set frequencies and activity rates of internal signals, which are signals that are not inputs or outputs but internal to the design. For a list of supported simulators, see the “VCD Data Entry” section of this chapter.
XAD - Output file that provides most of the information contained in the VCD file, but is much smaller in size to reduce runtime.
XML - Settings file from XPower. Settings for a design can be saved to an XML file and then reloaded into XPower for the same design. Data input such as frequencies, toggle rates, and capacitance loads can be saved to this file to avoid entering the same information the next time the design is loaded into XPower.