The next step in selecting appropriate DC/DC converters is to decide how much current is required to properly size the power supplies. Quiescent current information is easy to find, but dynamic power consumption, or the operating current, depends on how the FPGA is used. Xilinx tools allow an easy estimation of the required current for each FPGA. The Xilinx Power Estimator spreadsheet tool provides an accurate estimation of the current requirements before beginning the actual design. A good estimation will help prevent costly board component changes later in the design. The final design power estimation tool is called XPower Analyzer. This takes a user’s post-PAR design and simulation results as inputs to produce very accurate results. Both tools can be downloaded from the Xilinx website.