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For the flexibility of implementing any given Boolean function(s), the FPGA uses re-configurable building blocks called LUTs. The price for this reconfigurability is a large number of registers and multiplexers required to construct the FPGA. While researchers have been working on complex LUT structures to reduce the area and power for several years, most of these implementations come at the cost of performance penalty. This paper demonstrates simultaneous improvement in area, power, and performance in an FPGA by using special logic cells called Threshold Logic Cells (TLCs) (also known as binary perceptrons). The TLCs are capable of implementing a complex threshold function, which if implemented using conventional gates would require several levels of logic gates. The TLCs only require 7 SRAM cells and are significantly faster than the conventional LUTs. The implementation of the proposed FPGA architecture has been done using 28nm FDSOI standard cells and has been evaluated using ISCAS-85, ISCAS-89, and a few large industrial designs. Experiments demonstrate that the proposed architecture can be used to get an average reduction of 18.1% in configuration registers, 18.1% reduction in multiplexer count, 12.3% in Basic Logic Element (BLE) area, 16.3% in BLE power, 5.9% improvement in operating frequency, with a slight reduction in track count, routing area and routing power. The improvements are also demonstrated on the physically designed version of the architecture.
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FPGAs with Reconfigurable Threshold Logic Gates for Improved Performance, Power and Area
This paper proposes an alternative FPGA tile struc- ture that consists of three traditional LUTs combined with a new reconfigurable threshold logic cell (TLC). The TLC requires only 7 SRAM cells and can be configured to implement one of several threshold functions. The proposed architecture is implemented in a 28nm FDSOI process, and is evaluated on standard benchmark circuits and several large complex function blocks. The results demonstrate an average reduction of 8.9% in register count, 15.4% in multiplexer count, 7% average reduction in Basic Logic Element (BLE) area, and 8.2% average reduction in BLE power, with a maximum decrease in register count up to 64%, BLE multiplexer count up to 68%, BLE Area up to 51.6% and BLE power up to 61.6% without loss in performance. We also show a reduction of 21% in the area of a tile.
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- Award ID(s):
- 1701241
- PAR ID:
- 10099615
- Date Published:
- Journal Name:
- Field Programmable Logic
- Page Range / eLocation ID:
- 256 to 2563
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/FPL.2018.00051
