A Genuine Power-Gatable Reconfigurable Logic Chip with FeRAM Cells

Masahiro IIDA  Masahiro KOGA  Kazuki INOUE  Motoki AMAGASAKI  Yoshinobu ICHIDA  Mitsuro SAJI  Jun IIDA  Toshinori SUEYOSHI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E94-C   No.4   pp.548-556
Publication Date: 2011/04/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E94.C.548
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Circuits and Design Techniques for Advanced Large Scale Integration)
Category: 
Keyword: 
reconfigurable logic,  FeRAM,  power-gating,  non-volatile flip-flop,  NV-FF,  VGLC,  

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Summary: 
An advantage of an RLD (reconfigurable logic device) such as an FPGA (field programmable gate array) is that it can be customized after being manufactured. Due to the aggressive technology scaling, device density is increasing, and it has become a serious problem in power consumption accordingly. In SoC of embedded systems, power gating is one of the major power reduction techniques. However, it is difficult to adopt SRAM-based RLDs because of the high overhead and SRAM being volatile. In this paper, we describe a TEG (test element group) chip of a reconfigurable logic based FeRAM (ferroelectric random access memory) technology. FeRAM brings reconfigurable logic devices the advantage of being a genuine power gater. The chip employs island-style routing architecture and uses a variable grain logic cell as a logic block. A NV-FF (non-volatile flip-flop), which contains FeRAM, a FF, and power-gating control circuits, is used as both configuration memories and FFs in a logic block. The NV-FF can transmit data between FeRAM and FF automatically when a power source is turned off/on. Thus chip-level power gating is possible. The hibernate/restore time is less than 1 ms. The chip has 1818 logic blocks and an area of 54.76 mm2.