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Article
Publication date: 16 August 2021

Wenhua Huang, Juan Ren, Jinglong Jiang and J. Cheng

Quantum-dot Cellular Automata (QCA) is a new nano-scale transistor-less computing model. To address the scaling limitations of complementary-metal-oxide-semiconductor technology…

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Abstract

Purpose

Quantum-dot Cellular Automata (QCA) is a new nano-scale transistor-less computing model. To address the scaling limitations of complementary-metal-oxide-semiconductor technology, QCA seeks to produce general computation with better results in terms of size, switching speed, energy and fault-tolerant at the nano-scale. Currently, binary information is interpreted in this technology, relying on the distribution of the arrangement of electrons in chemical molecules. Using the coplanar topology in the design of a fault-tolerant digital comparator can improve the comparator’s performance. This paper aims to present the coplanar design of a fault-tolerant digital comparator based on the majority and inverter gate in the QCA.

Design/methodology/approach

As the digital comparator is one of the essential digital circuits, in the present study, a new fault-tolerant architecture is proposed for a digital comparator based on QCA. The proposed coplanar design is realized using coplanar inverters and majority gates. The QCADesigner 2.0.3 simulator is used to simulate the suggested new fault-tolerant coplanar digital comparator.

Findings

Four elements, including cell misalignment, cell missing, extra cell and cell dislocation, are evaluated and analyzed in QCADesigner 2.0.3. The outcomes of the study demonstrate that the logical function of the built circuit is accurate. In the presence of a single missed defect, this fault-tolerant digital comparator architecture will achieve 100% fault tolerance. Also, this comparator is above 90% fault-tolerant under single-cell displacement faults and is above 95% fault-tolerant under single-cell missing defects.

Originality/value

A novel structure for the fault-tolerant digital comparator in the QCA technology was proposed used by coplanar majority and inverter. Also, the performance metrics and obtained results establish that the coplanar design can be used in the QCA circuits to produce optimized and fault-tolerant circuits.

Details

Microelectronics International, vol. 38 no. 4
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 15 February 2021

Sankit Kassa, Prateek Gupta, Manoj Kumar, Thompson Stephan and Ramani Kannan

In nano-scale-based very large scale integration technology, quantum-dot cellular automata (QCA) is considered as a strong and capable technology to replace the well-known…

Abstract

Purpose

In nano-scale-based very large scale integration technology, quantum-dot cellular automata (QCA) is considered as a strong and capable technology to replace the well-known complementary metal oxide semiconductor technology. In QCA technique, rotated majority gate (RMG) design is not explored greatly, and therefore, its advantages compared to original majority gate are unnoticed. This paper aims to provide a thorough observation at RMG gate with its capability to build robust circuits.

Design/methodology/approach

This paper presents a new methodology for structuring reliable 2n-bit full adder (FA) circuit design in QCA utilizing RMG. Mathematical proof is provided for RMG gate structure. A new 1-bit FA circuit design is projected here, which is constructed with RMG gate and clock-zone-based crossover approach in its configuration.

Findings

A new structure of a FA is projected in this paper. The proposed design uses only 50 number of QCA cells in its implementation with a latency of 3 clock zones. The proposed 1-bit FA design conception has been checked for its structure robustness by designing various 2, 4, 8, 16, 32 and 64-bit FA designs. The proposed FA designs save power from 46.87% to 25.55% at maximum energy dissipation of circuit level, 39.05% to 23.36% at average energy dissipation of circuit-level and 42.03% to 37.18% at average switching energy dissipation of circuit level.

Originality/value

This paper fulfills the gape of focused research for RMG with its detailed mathematical modeling analysis.

Details

Circuit World, vol. 48 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 26 July 2021

Kalpana Kasilingam and Paulchamy Balaiah

The nano-router would be a mastery device for providing high-speed data delivery. Here nano-router with a space-efficient crossbar scheduler is used for making absolutely less…

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Abstract

Purpose

The nano-router would be a mastery device for providing high-speed data delivery. Here nano-router with a space-efficient crossbar scheduler is used for making absolutely less consumption in power.

Design/methodology/approach

In the emerging modern technology, every one of us is expecting a delivery of data at a high speed. To achieve high-speed delivery the authors are using the router. The router used here is at nanoscale reading which provides a compact size.

Findings

This can be implemented using the modern tools called Quantum-dot Cellular Automata (QCA) which is operated without the use of a transistor. As conventional complementary metal oxide semiconductor (CMOS) designs have some limitations such as low density, high power consumption and requirement of a large area.

Research limitations/implications

To overcome these limitations the QCA is used. It characterizes capability is used to substituting CMOS technology. The round-robin fashion is used in a high-speed space-efficient crossbar scheduler.

Practical implications

The simulation of the planned circuit with notional information established the practical identity of the scheme.

Social implications

The proposed nano router can be stimulated in the QCA environment using the QCADesigner tool and the power of the router can be calculated with the QCADesigner–E tool.

Originality/value

The proposed nano router can be stimulated in the QCA environment using the QCADesigner tool and the power of the router can be calculated with the QCADesigner–E tool. In this work, the performance of the router can be done in both the QCA environment and CMOS technology.

Article
Publication date: 25 November 2019

Ali H. Majeed, Esam Alkaldy, Mohd Shamian Zainal, Keivan Navi and Danial Nor

Quantum-dot cellular automata (QCA) has attracted computer scientists as new emerging nanotechnology for replacement the current CMOS technology because it has unique…

Abstract

Purpose

Quantum-dot cellular automata (QCA) has attracted computer scientists as new emerging nanotechnology for replacement the current CMOS technology because it has unique characteristics such as high frequency, extremely small feature size and low power consumption. The main building blocks in QCA are the majority gate and inverter so any Boolean function can be represented using these gates. Many important circuits were the target for implemented in this technology in an optimal form, such as random-access memory (RAM) cell. QCA-RAM cells were introduced in literature with different forms but most of them are not optimized enough. This paper aims to demonstrate QCA inherent capabilities that can facilitate the design of many important gates such as the XOR gate and multiplexer (MUX) without following any Boolean function to get an optimum design in terms of complexity and delay.

Design/methodology/approach

In this paper, a novel structure of QCA-MUX in an optimal form will be used to design two unique structures of a RAM cell. The proposed RAM cells are the lowest cost required compared with different counterparts. The presented RAM cells used a new approach that follows the new suggested block diagram. The presented circuits are simulated and tested with QCADesigner and QCAPro tools.

Findings

The comparison of the proposed circuits with the previously reported in the literature show noticeable improvements in speed, area, and the number of cells. The cost function analysis results for the proposed RAM cells show significant improvement compared to older circuits.

Originality/value

A novel structure of QCA-MUX in an optimal form will be used to design two unique structures of a RAM cell.

Details

Circuit World, vol. 46 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 22 July 2021

Ali Majeed and Esam Alkaldy

This study aims to replace current multi-layer and coplanar wire crossing methods in QCA technology to avoid fabrication difficulties caused by them.

Abstract

Purpose

This study aims to replace current multi-layer and coplanar wire crossing methods in QCA technology to avoid fabrication difficulties caused by them.

Design/methodology/approach

Quantum-dot cellular automata (QCA) is one of the newly emerging nanoelectronics technology tools that is proposed as a good replacement for complementary metal oxide semiconductor (CMOS) technology. This technology has many challenges, among them being component interconnection and signal routing. This paper will propose a new wire crossing method to enhance layout use in a single layer. The presented method depends on the central cell clock phase to enable two signals to cross over without interference. QCADesigner software is used to simulate a full adder circuit designed with the proposed wire crossing method to be used as a benchmark for further analysis of the presented wire crossing approach. QCAPro software is used for power dissipation analysis of the proposed adder.

Findings

A new cost function is presented in this paper to draw attention to the fabrication difficulties of the technology when designing QCA circuits. This function is applied to the selected benchmark circuit, and the results show good performance of the proposed method compared to others. The improvement is around 59, 33 and 75% compared to the best reported multi-layer wire crossing, coplanar wire crossing and logical crossing, respectively. The power dissipation analysis shows that the proposed method does not cause any extra power consumption in the circuit.

Originality/value

In this paper, a new approach is developed to bypass the wire crossing problem in the QCA technique.

Details

Circuit World, vol. 49 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 21 May 2020

Rupali Singh and Devendra Kumar Sharma

Quantum-dot cellular automata (QCA) is a promising technology, which seems to be the prospective substitute for complementary metal-oxide semiconductor (CMOS). It is a high speed…

Abstract

Purpose

Quantum-dot cellular automata (QCA) is a promising technology, which seems to be the prospective substitute for complementary metal-oxide semiconductor (CMOS). It is a high speed, high density and low power paradigm producing efficient circuits. These days, most of the smart devices used for computing, make use of random access memory (RAM). To enhance the performance of a RAM cell, researchers are putting effort to minimize its area and access time. Multilayer structures in QCA framework are area efficient, fast and immune to the random interference. Unlike CMOS, QCA multilayer architectures can be designed using active components on different layers. Thus, using multilayer topology in the design of a RAM cell, which is not yet reported in the literature can improve the performance of RAM and hence, the computing device. This paper aims to present the modular design of RAM cell with multilayer structures in the QCA framework. The fundamental modules such as XOR gate, 2:1 multiplexer and D latch are proposed here using multilayer formations with the goal of designing a RAM cell with the provision of read, write, set and reset control.

Design/methodology/approach

All the modules used to design a RAM cell are designed using multilayer approach in QCA framework.

Findings

The proposed multilayer RAM cell is optimized and has shown an improvement of 20% in cell count, 30% in area, 25% in area latency product and 48.8% in cost function over the other efficient RAM designs with set/reset ability reported earlier. The proposed RAM cell is further analyzed for the fault tolerance and power dissipation.

Research limitations/implications

Due to the multilayer structure, the complexity of the circuit enhances which can be eliminated using simple architectures.

Originality/value

The performance metrics and results obtained establish that the multilayer approach can be implemented in the QCA circuit to produce area efficient and optimized sequential circuits such as a latch, flip flop and memory cells.

Details

Circuit World, vol. 47 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

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