Implementation of a High-Speed Asynchronous Data-Transfer Chip Based on Multiple-Valued Current-Signal Multiplexing

Tomohiro TAKAHASHI  Takahiro HANYU  

IEICE TRANSACTIONS on Electronics   Vol.E89-C   No.11   pp.1598-1604
Publication Date: 2006/11/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e89-c.11.1598
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Novel Device Architectures and System Integration Technologies)
network-on-chip (NoC),  delay-insensitive,  dual-rail encoding,  globally asynchronous locally synchronous (GALS),  point-to-point communication,  

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This paper presents an asynchronous multiple-valued current-mode data-transfer controller chip based on a 1-phase dual-rail encoding technique. The proposed encoding technique enables "one-way delay" asynchronous data transfer because request and acknowledge signals can be transmitted simultaneously and valid states are detected by calculating the sum of dual-rail codewords. Since a key component, a current-to-voltage conversion circuit in a valid-state detector, is tuned so as to obtain a sufficient voltage range to improve switching speed of a comparator, signal detection can be performed quickly in spite of using 6-level signals. It is evaluated using HSPICE simulation with a 0.18-µm CMOS that the throughput of the proposed circuit based on the 1-phase dual-rail scheme attains 435 Mbps/wire which is 2.9 times faster than that of a CMOS circuit based on a conventional 4-phase dual-rail scheme. The test chip is fabricated, and the asynchronous data-transfer behavior of the proposed scheme is confirmed.