Optimization and Verification of Current-Mode Multiple-Valued Digit ORNS Arithmetic Circuits

Motoi INABA  Koichi TANNO  Hiroki TAMURA  Okihiko ISHIZUKA  

IEICE TRANSACTIONS on Information and Systems   Vol.E93-D   No.8   pp.2073-2079
Publication Date: 2010/08/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.E93.D.2073
Print ISSN: 0916-8532
Type of Manuscript: Special Section PAPER (Special Section on Multiple-Valued Logic and VLSI Computing)
Category: Multiple-Valued VLSI Technology
multiple-valued logic,  overlap resolution number system,  current-mode circuit,  weak-inversion region,  

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In this paper, optimization and verification of the current-mode multiple-valued digit ORNS arithmetic circuits are presented. The multiple-valued digit ORNS is the redundant number system using digit values in the multiple-valued logic and it realizes the full-parallel calculation without any ripple carry propagation. First, the 4-bit addition and multiplication algorithms employing the multiple-valued digit ORNS are optimized through logic-level analyses. In the multiplier, the maximum digit value and the number of modulo operations in series are successfully reduced from 49 to 29 and from 3 to 2, respectively, by the arrangement of addition lines. Next, circuit components such as a current mirror are verified using HSPICE. The proposed switched current mirror which has functions of a current mirror and an analog switch is effective to reduce the minimum operation voltage by about 0.13 volt. Besides an ordinary strong-inversion region, the circuit components operated under the weak-inversion region show good simulation results with the unit current of 10 nanoamperes, and it brings both of the lower power dissipation and the stable operation under the lower supply voltage.