Design of Area Efficient Shift Register and Scan Flip-Flop based on QCA Technology
05 Mar 2021-pp 716-719
TL;DR: In this paper, a 5-input majority gate (MG) based logic circuit is proposed. And the proposed circuits are advantages in terms of various circuit parameters such as cell counts, area, and gate count compared to the previous circuits implemented with 3-input MG.
Abstract: A growing substitute to the CMOS technology to structure the digital circuits is Quantum-dot Cellular Automata (QCA) Technology. The future nano digital circuits using QCA technology are very advantageous in context to low power consumption, device density, and speed. The standard logic elements in QCA are Majority Gate (MG) and Inverter. This paper presents a 5-input MG based logic circuits. The 3-input MG has some demerits; mainly, it needs more gates to implement complex functions. The high-level synthesis circuits such as multiplexer, shift register, and scan Flip-flops are implemented using the 5-input MG. The proposed circuits are advantages in terms of various circuit parameters such as cell counts, area, and gate count compared to the previous circuits implemented with 3-input MG.
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01 Jan 2023
TL;DR: A literature survey of the D flip-flop designs in quantum-dot cellular automata (QCA) can be found in this article , where a comparison is done between existing designs in literature and their optimized designs on the basis of parameters like number of cells used, area occupied by the cells and latency.
Abstract: Digital circuits designed at a nano-scale with the growing use of technologies like quantum-dot cellular automata (QCA) are beneficial over the orthodox CMOS regime in context with certain parameters like lower power consumption, high speed and density of the device. This paper presents a literature survey of the D flip-flop designs in QCA. This is followed by proposed optimized circuits for these existing D flip-flop designs. The comparison is done between existing designs in literature and their optimized designs on the basis of parameters like number of cells used, area occupied by the cells and latency. After analysing the performance of the proposed design, it is found that it achieves performance improvements up to 62.71% over previous designs.
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TL;DR: In this article, the authors proposed a new paradigm for computing with cellular automata (CAS) composed of arrays of quantum devices, which is called edge driven computing (EDC), where input, output and power are delivered at the edge of the CA array only; no direct flow of information or energy to internal cells is required.
Abstract: The authors formulate a new paradigm for computing with cellular automata (CAS) composed of arrays of quantum devices-quantum cellular automata. Computing in such a paradigm is edge driven. Input, output, and power are delivered at the edge of the CA array only; no direct flow of information or energy to internal cells is required. Computing in this paradigm is also computing with the ground state. The architecture is so designed that the ground-state configuration of the array, subject to boundary conditions determined by the input, yields the computational result. The authors propose a specific realization of these ideas using two-electron cells composed of quantum dots. The charge density in the cell is very highly polarized (aligned) along one of the two cell axes, suggestive of a two-state CA. The polarization of one cell induces a polarization in a neighboring cell through the Coulomb interaction in a very non-linear fashion. Quantum cellular automata can perform useful computing. The authors show that AND gates, OR gates, and inverters can be constructed and interconnected.
1,540 citations
TL;DR: This paper analyzes the reasons of the failures of adder designs using QCA technology, and proposes adders that exploit proper clocking schemes.
Abstract: Quantum-dot cellular automata (QCA) is attracting a lot of attention due to its extremely small feature size and ultralow power consumption. Up to now, several adder designs using QCA technology have been proposed. However, it was found that not all of the designs function properly. This paper analyzes the reasons of the failures and proposes adders that exploit proper clocking schemes
211 citations
TL;DR: This study presents a novel approach to designing efficient QCA-based circuits based on Boolean expressions achieved from reconfiguration of five-input and three-input majority gates, and simple and dense multiplexer and Exclusive-or structures are implemented.
Abstract: Quantum-dot cellular automata (QCA) are a transistorless computation approach which encodes binary information via configuration of charges among quantum dots. The fundamental QCA logic primitives are majority and inverter gates which can be utilized to design various QCA circuits. This study presents a novel approach to designing efficient QCA-based circuits based on Boolean expressions achieved from reconfiguration of five-input and three-input majority gates. Whereas the multiplexer and Exclusive-or are the most important fundamental logical circuits in digital systems, designing efficient and single layer structures without coplanar cross-over wiring is advantageous in QCA technology. In order to demonstrate the efficiency and usefulness of the proposed approach, simple and dense multiplexer and Exclusive-or structures are implemented. The proposed designs have significant improvement in terms of area, complexity, latency, and gate count in comparison to previous designs. The correct logical functionalities of presented structures have been authenticated using QCA designer tool.
76 citations
TL;DR: A novel 5-input majority gate for QCA is proposed in this paper which is suitable for designing QCA circuits in a simple and symmetric manner and simulation results and physical proofs confirm the usefulness of the proposed gate design for designing any digital circuit.
Abstract: In a very fast growth of very large scale integration (VLSI) technology, it is the demand and necessity of time to achieve a reliable design with low power consumption. The quantum dot cellular automata (QCA), due to its small size, very high switching speed and ultra-low power consumption, can be an alternative for CMOS VLSI technology at nano-scale level. A novel 5-input majority gate for QCA is proposed in this paper which is suitable for designing QCA circuits in a simple and symmetric manner. Based on it, we have designed a full adder with some physical proofs provided for the functions of Boolean techniques to verify the functionality of the proposed devices properly. For computer simulations analysis, functionality of full adder has been checked using the QCADesigner tool. Both simulation results and physical proofs confirm the usefulness of our proposed gate design for designing any digital circuit.
32 citations
01 Jan 2014
TL;DR: In this paper, the design capability of the multiplexer in QCA is investigated implementing XOR, XNOR logic gate and arithmetic logic unit, and the design of efficient sequential circuits like D latch, T latch, D flip-flop, Scan flipflop and shift registers are designed.
Abstract: Quantum-dot cellular Automata (QCA), a viable alternative to current CMOS, is gaining its prominence in digital circuit due to its very high device density and clocking speed. This work targets design of efficient logic circuits based on QCA multiplexer. The design capability of the multiplexer in QCA is investigated implementing XOR, XNOR logic gate and arithmetic logic unit. Further, efficient sequential circuits like D latch, T latch, D flip-flop, Scan flip-flop, shift registers are designed using QCA multiplexer. Results obtained supports the fact that the proposed designs achieve significant improvement in terms of device density, cell count as well as clock delay than that of the other previous designs.
30 citations