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Asia-Pacific Microwave Conference (APMC)

The RSFQ Test-Timing Model for Delay Insensitive Data Processing Pipeline Design

Zhonghai Zhang, Guan Bo-ran

Published Mar 22, 2006• 0 citations
Publisher

Abstract

A novel asynchronous RSFQ digital circuit model, test-timed RSFQ digital model (TT) is proposed in this paper. With this asynchronous approach, data is transferred in a delay-insensitive fashion to avoid the problems aroused from the global clock distribution and the timing uncertainty. In the TT model, the timing pulse to the logic module will be generated with a test logic module, instead of the time delay module, which should be necessary in most asynchronous circuits. The elimination of the delay module can basically solve the timing uncertainty bothered in the RSFQ digital system layouts. The transient simulations and logic simulations have been made for the OR module and a RSFQ data processing pipeline based on the TT scheme has been designed. The logic simulations have also been made for this pipeline, and the results showed its feasibility and satisfaction for the RSFQ digital system applications.

DOI
10.1109/apmc.2005.1606813

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A novel asynchronous RSFQ digital circuit model, test-timed RSFQ digital model (TT) is proposed in this paper. With this asynchronous approach, data is transferred in a delay-insensitive fashion to avoid the problems aroused from the global clock distribution and the timing uncertainty. In the TT model, the timing pulse to the logic module will be generated with a test logic module, instead of the time delay module, which should be necessary in most asynchronous circuits. The elimination of the delay module can basically solve the timing uncertainty bothered in the RSFQ digital system layouts. The transient simulations and logic simulations have been made for the OR module and a RSFQ data processing pipeline based on the TT scheme has been designed. The logic simulations have also been made for this pipeline, and the results showed its feasibility and satisfaction for the RSFQ digital system applications.
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This paper presents a basic circuit concept for pulse-driven asynchronous circuits using superconducting rapid single-flux-quantum (RSFQ) logic gates. Today's computer systems perform using a synchronous clock distributed over the whole system. The distribution of the clock signal becomes more difficult as the clock frequency increases because the wavelength of the clock signal becomes shorter than the system size. One way to solve this problem is to use asynchronous circuits in which all circuits perform their functions only under the law of cause and effect. We propose an implementation of the basic asynchronous circuit performing OR/AND logic operations between SFQ pulses. The operations are confirmed by SPICE simulation. We will show a design method for combinational circuits using the proposed basic circuits.