The proliferation of voltage input rails for delivering point-of-load (POL) power to FPGAs is making power supply designs ever more challenging. As a result, encapsulated power modules are seeing increased use in telecom, cloud computing and industrial equipment because they operate as self-contained power management systems. They are easier to use than discrete solutions and speed time-to-market for both experienced and
novice power-supply designers. Modules include all of the major components -- PWM controller, FETs, inductor and compensation circuitry -- with only the input capacitor and output capacitor needed to create an entire power supply.
This article will highlight a graphical user interface (GUI) that configures, validates and monitors the FPGA’s power supply architecture, and we will explain the GUI’s sequencing feature to power up the voltage rails, and select the power sequence order and rise and fall times.
Power Supply Software Tools
FPGA manufacturers provide various tools that help estimate the power requirements during the power supply planning stage. These tools take into account device selection, architecture evaluation and thermal modelling to arrive at an estimated solution. For example, power supply designers can use the Xilinx Power Estimator (XPE) tool at the pre-design and pre-implementation phase. Power management vendors then take the results from XPE and use the information to provide the necessary guidance for component selection of the power supply.
Since the programmable FPGA is a variable at the planning stage, rule of thumbs can be established for the device families that will vary based on FPGA utilization. Low, middle and high utilization estimates can help determine the power demand under these conditions. Table 1 breaks up the power requirements with a low, mid, and high current estimation for a Virtex 7 FPGA.
Using the Table 1 chart as our guide, we can select various options such as analog discrete or module solutions and digital