Xilinx FPGAs provide a tremendous amount of design flexibility. Because they are so versatile, defining your power requirements isn’t as straightforward as simply reading an input voltage and load current requirement. You have core rails, auxiliary rails, bank rails and more that provide power to different portions of the chip. Some of these voltages are fixed and some are adjustable to unlock better performance or allow you to set I/O voltage levels compatible with other devices you want to communicate with.
With All Programmable System on Chips like the Zynq and Zynq UltraScale+ devices from Xilinx, you also introduce separate power domains for programmable logic (PL) and processing subsystems (PS). All of these supplies have requirements for sequencing, rise times, accuracy and noise sensitivity. These requirements vary by type, with supplies powering core logic and transceivers requiring higher accuracy and lower noise to achieve maximum performance.
In addition to providing documentation on electrical characteristics, Xilinx also provides a spreadsheet-based estimation tool which is crucial to the upfront design of your product. Xilinx Power Estimator (or XPE) should be a standard part of your design process any time you are working with a Xilinx FPGA or SoC. The tool allows you to enter the specific device you are working with, your resource utilization, physical environment parameters and more. Based on your inputs to the spreadsheet, you will be given a summary of the estimated worst case power consumption of your device based on the profile you defined. This estimation errs on the high side, and should be used when defining your power budget. Below you will find 2 videos that I’ve previously created specifically around using this tool. The first video is general XPE use and the second focuses on defining transceiver power requirements. These walk-throughs should help you understand what you are looking at when you open the tool and give you a pretty good understanding of how to fill in the data.
Xilinx periodically updates this tool so when you are starting a new design be sure to download the latest version from - www.xilinx.com/power
