Compact Stochastic Computing Circuits Using the Latching Function of RSFQ Circuits for Computing Polynomials

Abstract

Stochastic computing (SC) is a method of expressing a numerical value by the appearance ratio of 1 in a bitstream to perform an operation. Rapid single flux quantum (RSFQ) circuits can handle SC naturally and operate at ultra-high speed. RSFQ SC circuits are suitable for applications tolerating error. This paper presents a design method of RSFQ SC circuits to calculate polynomials. Using the proposed design method, an internal circuit is designed to feed bitstreams of coefficients from bitstreams of constant to reduce large stochastic number generators. The method inserts storage elements to reduce correlations of signals, and thereby reduce the calculation error of the circuit. Additionally, it minimizes the number of inserted D flip-flops utilizing the latching function of gate inputs of RSFQ logic gates.