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Article
Publication date: 23 March 2020

Pramod Kumar Patel, M.M. Malik and Tarun Kumar Gutpa

The performance of the conventional 6T SRAM cell can be improved by using GNRFET devices with multi-threshold technology. The proposed cell shows the strong capability to operate…

Abstract

Purpose

The performance of the conventional 6T SRAM cell can be improved by using GNRFET devices with multi-threshold technology. The proposed cell shows the strong capability to operate at the minimum supply voltage of 325 mV, whereas the conventional Si-CMOS 6 T SRAM unable to operate below 725 mV, which result in an acceptable failure rate.The advance of Si-CMOS (complementary metal-oxide-semiconductor) based 6 T SRAM cell faces inherent limitation with aggressive downscaling. Hence, there is a need to propose alternatives for the conventional cells.

Design/methodology/approach

This study aims to improve the performance of the conventional 6T SRAM cell using dual threshold technology, device sizing, optimization of supply voltage under process variation with GNRFET technology. Further performance can be enhanced by resolving half-select issue.

Findings

The GNRFET-based 6T SRAM cell demonstrates that it is capable of continued improve the performance under the process, voltage, and temperature (PVT) variations significantly better than its CMOS counterpart.

Research limitations/implications

Nano-material fabrication technology of GNRFETs is in the early stage; hence, the different transistor models can be used to evaluate the parameters of future GNRFETs circuit.

Practical implications

GNRFET devices are suitable for implementing low power and high density SRAM cell.

Social implications

The conventional Si-CMOS 6 T SRAM cell is a core component and used as the mass storage element in cache memory in computer system organization, mobile phone and other data storage devices.

Originality/value

This paper presents a new approach to implement an alternative design of GNRFET -based 6T SRAM cell with doped reservoirs that also supports process variation. In addition, multi-threshold technology optimizes the performance of the proposed cell. The proposed design provides a means to analyze delay and power of GNRFET-based SRAM under process variation with considering edge roughness, and offers design and fabrication insights for cell in the future.

Details

Circuit World, vol. 46 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 3 December 2018

Sudhakar Jyothula

The purpose of this paper is to design a low power clock gating technique using Galeor approach by assimilated with replica path pulse triggered flip flop (RP-PTFF).

Abstract

Purpose

The purpose of this paper is to design a low power clock gating technique using Galeor approach by assimilated with replica path pulse triggered flip flop (RP-PTFF).

Design/methodology/approach

In the present scenario, the inclination of battery for portable devices has been increasing tremendously. Therefore, battery life has become an essential element for portable devices. To increase the battery life of portable devices such as communication devices, these have to be made with low power requirements. Hence, power consumption is one of the main issues in CMOS design. To reap a low-power battery with optimum delay constraints, a new methodology is proposed by using the advantages of a low leakage GALEOR approach. By integrating the proposed GALEOR technique with conventional PTFFs, a reduction in power consumption is achieved.

Findings

The design was implemented in mentor graphics EDA tools with 130 nm technology, and the proposed technique is compared with existing conventional PTFFs in terms of power consumption. The average power consumed by the proposed technique (RP-PTFF clock gating with the GALEOR technique) is reduced to 47 per cent compared to conventional PTFF for 100 per cent switching activity.

Originality/value

The study demonstrates that RP-PTFF with clock gating using the GALEOR approach is a design that is superior to the conventional PTFFs.

Details

World Journal of Engineering, vol. 15 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 24 November 2021

Tulasi Naga Jyothi Kolanti and Vasundhara Patel K.S.

The purpose of this paper is to design multiplexers (MUXs) based on ternary half subtractor and full subtractor using carbon nanotube field-effect transistors.

Abstract

Purpose

The purpose of this paper is to design multiplexers (MUXs) based on ternary half subtractor and full subtractor using carbon nanotube field-effect transistors.

Design/methodology/approach

Conventionally, the binary logic functions are developed by using the binary decision diagram (BDD) systems. Each node in BDD is replaced by 2:1 MUX to implement the digital circuits. Similarly, in the ternary decision diagram, each node has to be replaced by 3:1 MUX. In this paper, ternary transformed BDD is used to design the ternary subtractors using 2:1 MUXs.

Findings

The performance of the proposed ternary half subtractor and full subtractor using the 2:1 MUX are compared with the 3:1 MUX-based ternary circuits. It has been observed that the delay, power and power delay product values are reduced, respectively, by 67.6%, 84.3%, 94.9% for half subtractor and 67.7%, 70.1%, 90.3% for full subtractor. From the Monte Carlo simulations, it is observed that the propagation delay and power dissipation of the proposed subtractors are increased by increasing the channel length due to process variations. The stability test is also performed and observed that the stability increases as the channel length and diameter are increased.

Originality/value

The proposed half subtractor and full subtractor show better performance over the existing subtractors.

Details

Circuit World, vol. 49 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 3 February 2020

Afreen Khursheed and Kavita Khare

This paper is an unprecedented effort to resolve the performance issue of very large scale integrated circuits (VLSI) interconnects encountered because of the scaling of device…

Abstract

Purpose

This paper is an unprecedented effort to resolve the performance issue of very large scale integrated circuits (VLSI) interconnects encountered because of the scaling of device dimensions. Repeater interpolation technique is an effective approach for enhancing speed of interconnect network. Proposed buffers as repeater are modeled by using dual chirality multi-Vt technology to reduce delay besides mitigating average power consumption. Interconnects modeled with carbon nanotube (CNT) technology are compared with copper interconnect for various lengths. Buffer circuits are designed with both CNT and metal oxide semiconductor technology for comparison by using various combination of (CMOSFET repeater-Cu interconnect) and (CNTFET repeater-CNT interconnect). Compared to conventional buffer, ProposedBuffer1 saves dynamic power by 84.86%, leakage power by 88% and offers reduction in delay by 72%. ProposedBuffer2 brings about dynamic power saving of 99.94%, leakage power saving of 93%, but causes delay penalty. Simulation using Stanford SPICE model for CNT and silicon-field effective transistor berkeley short-channel IGFET Model4 (BSIM4) predictive technology model (PTM) for MOS is done in H simulation program with integrated circuit emphasis for 32 nm.

Design/methodology/approach

Usually, the dynamic power consumption dominates the total power, while the leakage power has a negligible effect. But with the scaling of device technology, leakage power has become one of the important factors of consideration in low power design techniques. Various strategies are explored to suppress the leakage power in standby mode. The adoption of a multi-threshold design strategy is an effective approach to improve the performance of buffer circuits without compromising on the delay and area overhead. Unlike MOS technology, to implement multi-Vt transistors in case of CNT technology is quite easy. It can be achieved by varying diameter of carbon nanotubes using chirality control.

Findings

An unprecedented approach is taken for optimizing the delay and power dissipation and hence drastically reducing energy consumption by keeping proper harmony between wire technology and repeater-buffer technology. This paper proposes two novel ultra-low power buffers (PB1 and PB2) as repeaters for high-speed interconnect applications in portable devices. PB1 buffer implemented with high-speed CML technique nested with multi-threshold (Vt) technology sleep transistor so as to improve the speed along with a reduction in standby power consumption. PB2 is judicially implemented by inserting separable sized, dual chirality P type carbon nanotube field effective transistors. The HSpice simulation results justify the correctness of schemes.

Originality/value

Result analysis points out that compared to conventional Cu interconnect, the CNT interconnects paired with Proposed CNTFET buffer designs are more energy efficient. PB1 saves dynamic power by 84.86%, reduces propagation delay by 72% and leakage power consumption by 88%. PB2 brings about dynamic power saving of 99.4%, leakage power saving of 93%, with improvement in speed by 52%. This is mainly because of the fact that CNT interconnect offers low resistance and CNTFET drivers have high mobility and ballistic mode of operation.

Details

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

Keywords

Article
Publication date: 2 May 2017

Sudhakar Jyothula and Sushma K.

The purpose of this paper is to present a single-precision floating-point multiplier where a low-power operation is attained through the reduction of switching activity. A…

Abstract

Purpose

The purpose of this paper is to present a single-precision floating-point multiplier where a low-power operation is attained through the reduction of switching activity. A floating-point multiplier is the basic building block for many applications such as digital signal processing (DSP) processors and multimedia applications involving a large dynamic range.

Design/methodology/approach

A floating-point multiplier was implemented in asynchronous logic such as multi-threshold null conventional logic and the proposed multi-threshold dual spacer dual rail delay insensitive logic (MTD3L). The proposed logic deals with high performance and energy efficiency.

Findings

The Institute of Electrical and Electronics Engineering (IEEE) has provided a standard to define the floating-point representation, which is known as the IEEE 754 standard. Rounding has not been implemented because it is not suitable for high-precision applications.

Originality/value

The performance aspects of the proposed asynchronous MTD3L floating-point multiplier are obtained using a Mentor Graphics tool and are compared with those of the existing asynchronous logic.

Details

Circuit World, vol. 43 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 24 June 2020

Kanika Monga, Nitin Chaturvedi and S. Gurunarayanan

Emerging event-driven applications such as the internet-of-things requires an ultra-low power operation to prolong battery life. Shutting down non-functional block during standby…

Abstract

Purpose

Emerging event-driven applications such as the internet-of-things requires an ultra-low power operation to prolong battery life. Shutting down non-functional block during standby mode is an efficient way to save power. However, it results in a loss of system state, and a considerable amount of energy is required to restore the system state. Conventional state retentive flip-flops have an “Always ON” circuitry, which results in large leakage power consumption, especially during long standby periods. Therefore, this paper aims to explore the emerging non-volatile memory element spin transfer torque-magnetic tunnel junction (STT-MTJ) as one the prospective candidate to obtain a low-power solution to state retention.

Design/methodology/approach

The conventional D flip-flop is modified by using STT-MTJ to incorporate non-volatility in slave latch. Two novel designs are proposed in this paper, which can store the data of a flip-flip into the MTJs before power off and restores after power on to resume the operation from pre-standby state.

Findings

A comparison of the proposed design with the conventional state retentive flip-flop shows 100 per cent reduction in leakage power during standby mode with 66-69 per cent active power and 55-64 per cent delay overhead. Also, a comparison with existing MTJ-based non-volatile flip-flop shows a reduction in energy consumption and area overhead. Furthermore, use of a fully depleted-silicon on insulator and fin field-effect transistor substituting a complementary metal oxide semiconductor results in 70-80 per cent reduction in the total power consumption.

Originality/value

Two novel state-retentive D flip-flops using STT-MTJ are proposed in this paper, which aims to obtain zero leakage power during standby mode.

Details

Circuit World, vol. 46 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 26 August 2014

Chern Sheng Lin, Pei-Feng Yang, Chi-Chin Lin and Yuen-Chang Hsu

– This study aimed to developed a defect detection system for a segment-type display module panel.

Abstract

Purpose

This study aimed to developed a defect detection system for a segment-type display module panel.

Design/methodology/approach

The system included a data acquisition card, a video camera, a computer and a display module on a testing table. The video camera captured the display pattern of the display module and transferred it to the computer through the data acquisition card. The dynamic multi-thresholding method and analysis as well as back propagation neural network classification was used to classify the detected defects.

Findings

The threshold values for the brightness at different positions in the display module image were obtained using the neural network and then stored in the look-up table, using two to six matrixes.

Originality/value

The recognition speed was faster and the system was more flexible in comparison to the previous system. The proposed method, using unsophisticated and economical equipment, was also verified as providing highly accurate results with a low error rate.

Details

Sensor Review, vol. 34 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 13 November 2009

Zhang Ming, Nie Hong, Wei Xiao‐hui, Qian Xiaomei and Zhou Enzhi

The purpose of this paper is to introduce a co‐simulation method to study the ground maneuvers of aircraft anti‐skid braking and steering.

6795

Abstract

Purpose

The purpose of this paper is to introduce a co‐simulation method to study the ground maneuvers of aircraft anti‐skid braking and steering.

Design/methodology/approach

A virtual prototype of aircraft is established in the multibody system dynamics software MSC.ADAMS/Aircraft. The anti‐skid braking control model, which adopts the multi‐threshold PID control method with a slip‐velocity‐controlled, pressure‐bias‐modulated (PBM) system, is established in MATLAB/Simulink. EASY5 is used to establish the hydraulic system of nose wheel steering. The ADAMS model is connected to block diagrams of the anti‐skid braking control model in MATLAB/Simulink, and is also connected to the block diagrams of nose wheel steering system model in EASY5, so that the ground maneuvers of aircraft anti‐skid braking and steering are simulated separately.

Findings

Results are presented to investigate the performance of anti‐skid braking system in aircraft anti‐skid simulation. In aircraft steering simulation, the influence of two important parameters on the forces acting on the tires is discussed in detail, and the safe area to prevent aircraft sideslip is obtained.

Originality/value

This paper presents an advanced method to study the ground maneuvers of aircraft anti‐skid braking and steering, and establishes an integrated aircraft model of airframe, landing gear, steering system, and anti‐skid braking system to investigate the interaction of each subsystem via simulation.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 28 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 21 August 2019

Yavar Safaei Mehrabani, Mehdi Bagherizadeh, Mohammad Hossein Shafiabadi and Abolghasem Ghasempour

This paper aims to present an inexact 4:2 compressor cell using carbon nanotube filed effect transistors (CNFETs).

Abstract

Purpose

This paper aims to present an inexact 4:2 compressor cell using carbon nanotube filed effect transistors (CNFETs).

Design/methodology/approach

To design this cell, the capacitive threshold logic (CTL) has been used.

Findings

To evaluate the proposed cell, comprehensive simulations are carried out at two levels of the circuit and image processing. At the circuit level, the HSPICE software has been used and the power consumption, delay, and power-delay product are calculated. Also, the power-delaytransistor count product (PDAP) is used to make a compromise between all metrics. On the other hand, the Monte Carlo analysis has been used to scrutinize the robustness of the proposed cell against the variations in the manufacturing process. The results of simulations at this level of abstraction indicate the superiority of the proposed cell to other circuits. At the application level, the MATLAB software is also used to evaluate the peak signal-to-noise ratio (PSNR) figure of merit. At this level, the two primary images are multiplied by a multiplier circuit consisting of 4:2 compressors. The results of this simulation also show the superiority of the proposed cell to others.

Originality/value

This cell significantly reduces the number of transistors and only consists of NOT gates.

Details

Circuit World, vol. 45 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 29 May 2020

Shilpi Birla, Sudip Mahanti and Neha Singh

The purpose of this paper is to propose a leakage reduction technique which will works for complementary metal oxide semiconductor (CMOS) and fin field effect transistor (FinFET)…

Abstract

Purpose

The purpose of this paper is to propose a leakage reduction technique which will works for complementary metal oxide semiconductor (CMOS) and fin field effect transistor (FinFET). Power consumption will always remain one of the major concerns for the integrated circuit (IC) designers. Presently, leakage power dominates the total power consumption, which is a severe issue. It is undoubtedly clear that the scaling of CMOS revolutionizes the IC industry. Still, on the contrary, scaling of the size of the transistor has raised leakage power as one of the significant threats to the IC industry. Scaling of the devices leads to the scaling of other device parameters, which includes threshold voltage also. The scaling of threshold voltage leads to an exponential increase in the sub-threshold current. So, many leakage reduction techniques have been proposed by researchers for CMOS from time to time. Even the other nano-scaled devices such as FinFET, carbon nanotube field effect transistor and tunneling field effect transistor, have been introduced, and FinFET is the one which has evolved as the most favorable candidate for replacing CMOS technology.

Design/methodology/approach

Because of its minimum leakage and without having limitation of the short channel effects, it gradually started replacing the CMOS. In this paper, the authors have proposed a technique for leakage reduction for circuits using nano-scaled devices such as CMOS and FinFET. They have compared the proposed PMOS FOOTER SLEEP with the existing leakage reduction techniques such as LECTOR technique, LECTOR FOOTER SLEEP technique. The proposed technique has been implemented using CMOS and FinFET devices. This study found that the proposed method reduces the average power, as well as leakage power reduction, for both CMOS and FinFET devices.

Findings

This study found that the proposed method reduces the average power as well as leakage power reduction for both CMOS and FinFET devices. The delay has been calculated for the proposed technique and the existing techniques, which verifies that the proposed technique is suitable for high-speed circuit applications. The authors have implemented higher order gates to verify the performance of the proposed circuit. The proposed method is suitable for deep-submicron CMOS technology and FinFET technology.

Originality/value

All the existing techniques were proposed for either CMOS device or FinFET device, but the authors have implemented all the techniques with both the devices and verified with the proposed technique for CMOS as well as FinFET devices.

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