Powering FPGAs made easy


Let me take a step back to acknowledge that powering FPGAs have become more complicated over time and I will explain this statement shortly.  But, the purpose of this blog is to help simplify the power solution for the FPGA to help you create a quick and easy solution.

Before you read any further, I want to point out that this particular blog is not meant for power experts (I don’t want to waste your time!) but, rather, for digital engineers that will be using the FPGA for their project or assignment and need to create a simple, quick and easy power solution to get their FPGA up and running.  

Now that I have narrowed down my audience, let me explain what I meant by ‘powering FPGAs have become more complicated over time.’ 

While powering an FPGA, you need to consider several aspects of power design such as:

  • Increased number of out voltage rails
  • Set point accuracy needed for the rails
  • Optimizing passive layout in the design for low ripple noise
  • AC transient response needed, and compensation loops

Let’s not forget sequencing and many more needed features.   A typical FPGA power solution on the FPGA development kit looks like the one showed in Figure 1 that requires additional expertise beyond just selecting the right device and inductor.  One needs to consider part placement and layout intricacies.

Typical FPGA power solution on FPGA development kit

Figure 1. Typical FPGA power solution

So, how can you simplify the design?

Luckily for us, there are solutions to help make things easy.  In this post, I want to focus on two innovative and creative technologies that will help you get to your design goal quickly and easily. 

The first technology I want to highlight is a design tool made for creating the power solution for your FPGA (paper designs with simulated results), WEBENCH FPGA Architect

WEBENCH FPGA Architect is a design tool that allows you to:

  1. Pick the FPGA vendor of your choice
  2. Pick the FPGA product family that you will be using
  3. Populate the power needs defined by the FPGA power estimator tool provided by the FPGA vendor

These simple steps will generate a power solution for your FPGA that you can optimize based on footprint, efficiency and cost.  This simple tool will give you a head start on your design by reducing the initial hurdle from days to minutes.

The second technology that truly helps simplify your design is integrated inductor power modules. 

Power modules primarily integrate the inductor into one IC package, but additionally, they integrate other external components such as FETs, compensation loop if it exists, feedback resistors and so on.  Power modules are feature rich. For example, the enable and power good pins can be used for sequencing and need minimal external components (input capacitors, output capacitors and perhaps one feedback resistor).  It helps simplify your power solution from Figure 1 to Figure 2.  The integrated inductor power modules have been used to power an FPGA and been deemed as an apt power solution by FPGA vendors.  These modules also help simplify your layout helping you turn around your design quicker than before.

Figure 2. Integrated inductor power module using LMZ30602 

Now that I have given you a quick tip on how to simplify your power design for FPGAs, please feel free to leave your comments on what other issues you face while designing your power solution.  This will help me address your issues and concerns in my next blog. 

Until then, cheers!

Related Resources:

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