Module‐based design method using clocking scheme for quantum‐dot cellular automata

Abstract

AbstractQuantum‐dot cellular automata (QCA) is a field‐coupled nanotechnology with unique computing paradigms to be one of the strong alternatives to replace the traditional complementary metal oxide semiconductor (CMOS) in the future in theory. With the development of its fabrication technique and increasing circuit scale, the modular design method of QCA circuits is promoted, which consists at least of two connotations: designing appropriate modules for circuits and allocating applicable clock to circuits. In this paper, a module‐based design method using a clocking scheme (MCS) in QCA is proposed, which can be categorized into the modular design methodology. A complete module library for constructing circuits and a flexible clocking scheme for driving them are correspondingly proposed for the MCS method. Compared to previous design methods, its library includes not only active modules but also passive modules to connect active modules to construct circuits, so that more complex circuits can then be synthesized with them. After that, the efficient clocking scheme with fixed clock zones and signal propagation directions that is designed according to the characteristics of the proposed library solves the clock allocation problem in complex circuits. Full adder, multi‐bit adder, D flip‐flop, and multi‐bit D flip‐flop are taken as examples to illustrate the performances of the proposed MCS method in designing combinational and sequential circuits, respectively. The experimental results show that this method is more suitable for modular design in QCA in contrast to previous methods.