FPGA Power Management

March 31, 2005

What is an FPGA?

A field-programmable gate array (FPGA) is an IC that can include thousands of identical, programmable logic cells. A matrix of wires and programmable switches interconnects individual logic cells. A typical design involves specifying the simple logic function for each cell and selectively closing the switches in the interconnect matrix. FPGAs are primarily used to prototype an IC-based system. When the design is finalized, designers can convert the logic into hardwired ICs that operate at higher speeds. To operate properly, the FPGA must employ appropriate power-management technology.

What are the powering requirements for an FPGA?

PGA power depends on the requirements of internal circuits. The FPGA has three major configurable elements: configurable logic blocks (CLBs), I/O blocks (IOBs), and interconnects. The CLBs provide the functional logic elements. The IOBs provide the interface between the package pins and internal signal lines. The programmable interconnect resources provide routing paths to connect the inputs and outputs of the CLBs and IOBs onto the appropriate networks. The voltage applied to the CLBs (or core) is designated VCCINT. VCCO is the voltage supplied for IOBs. Some FPGAs have an additional voltage input designated as VCCAUX.

What are typical voltage and current values for VCCINT?

Typical voltages are 1.2, 1.5, 1.8, 2.5, and 3 V, with currents up to 12 A. The larger the number of CLBs, the lower the voltage and higher the current. In addition, VCCINT should rise monotonically, with no dip allowed.

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About the Author

Sam Davis 2

Sam Davis was the editor-in-chief of Power Electronics Technology magazine and website that is now part of Electronic Design. He has 18 years experience in electronic engineering design and management, six years in public relations and 25 years as a trade press editor. He holds a BSEE from Case-Western Reserve University, and did graduate work at the same school and UCLA. Sam was the editor for PCIM, the predecessor to Power Electronics Technology, from 1984 to 2004. His engineering experience includes circuit and system design for Litton Systems, Bunker-Ramo, Rocketdyne, and Clevite Corporation. Design tasks included analog circuits, display systems, power supplies, underwater ordnance systems, and test systems. He also served as a program manager for a Litton Systems Navy program.

Sam is the author of Computer Data Displays, a book published by Prentice-Hall in the U.S. and Japan in 1969. He also authored the book Managing Electric Vehicle Power. He is also a recipient of the Jesse Neal Award for trade press editorial excellence, and has one patent for naval ship construction that simplifies electronic system integration.

You can also check out additional articles on his other author page

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