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Article
Publication date: 1 August 2016

Pawel Górecki and Krzysztof Górecki

The paper aims to consider the problem of the influence of mounting power metal-oxide semiconductor (MOS) transistors operating in the Totem–Pole circuit on energy losses…

Abstract

Purpose

The paper aims to consider the problem of the influence of mounting power metal-oxide semiconductor (MOS) transistors operating in the Totem–Pole circuit on energy losses in this circuit.

Design/methodology/approach

Using the computer simulation in SPICE software, the influence of such factors as on-state resistance of the channel of the MOS transistor, the self-heating phenomena in this transistor and resistance of wires connecting transistors with the other part of the circuit on characteristics of the considered circuit operating with resistor, inductor and capacitor (RLC) load is analyzed. The selected results of calculations are compared with the results of measurements.

Findings

On the basis of the obtained results of calculations, some recommendations concerning the manner of mounting the considered transistors, assuring a high value of watt-hour efficiency of the process of energy transfer to the load are formulated.

Research limitations/implications

The investigations were performed in the wide range of the frequency of the signal stimulating the considered circuit, but the results of calculations were presented for 2 selected values of this frequency only.

Practical implications

The considered analysis was performed for the circuit dedicated to power supplied of an elecrolyser.

Originality/value

Presented results of calculations prove that in some situations, the value of watt-hour efficiency of the considered circuit is determined by the length and the cross-section area of the applied wires bringing the signal to the connectors of the transistors and to load. On the other hand, self-heating phenomena in the power MOS transistors can lead to doubling power losses in these devices.

Details

Microelectronics International, vol. 33 no. 3
Type: Research Article
ISSN: 1356-5362

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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

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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Article
Publication date: 25 February 2014

G. Ramana Murthy, C. Senthilpari, P. Velrajkumar and Lim Tien Sze

Demand and popularity of portable electronic devices are driving the designers to strive for higher speeds, long battery life and more reliable designs. Recently, an…

Abstract

Purpose

Demand and popularity of portable electronic devices are driving the designers to strive for higher speeds, long battery life and more reliable designs. Recently, an overwhelming interest has been seen in the problems of designing digital systems with low power at no performance penalty. Most of the very large-scale integration applications, such as digital signal processing, image processing, video processing and microprocessors, extensively use arithmetic operations. Binary addition is considered as the most crucial part of the arithmetic unit because all other arithmetic operations usually involve addition. Building low-power and high-performance adder cells are of great interest these days, and any modifications made to the full adder would affect the system as a whole. The full adder design has attracted many designer's attention in recent years, and its power reduction is one of the important apprehensions of the designers. This paper presents a 1-bit full adder by using as few as six transistors (6-Ts) per bit in its design. The paper aims to discuss these issues.

Design/methodology/approach

The outcome of the proposed adder architectural design is based on micro-architectural specification. This is a textual description, and adder's schematic can accurately predict the performance, power, propagation delay and area of the design. It is designed with a combination of multiplexing control input (MCIT) and Boolean identities. The proposed design features lower operating voltage, higher computing speed and lower energy consumption due to the efficient operation of 6-T adder cell. The design adopts MCIT technique effectively to alleviate the threshold voltage loss problem commonly encountered in pass transistor logic design.

Findings

The proposed adder circuit simulated results are used to verify the correctness and timing of each component. According to the design concepts, the simulated results are compared to the existing adders from the literature, and the significant improvements in the proposed adder are observed. Some of the drawbacks of the existing adder circuits from the literature are as follows: The Shannon theorem-based adder gives voltage swing restoration in sum circuit. Due to this problem, the Shannon circuit consumes high power and operates at low speed. The MUX-14T adder circuit is designed by using multiplexer concept which has a complex node in its design paradigm. The node drivability of input consumes high power to transmit the voltage level. The MCIT-7T adder circuit is designed by using MCIT technique, which consumes more power and leads to high power consumption in the circuit. The MUX-12T adder circuit is designed by MCIT technique. The carry circuit has buffering restoration unit, and its complement leads to high power dissipation and propagation delay.

Originality/value

The new 6-T full adder circuit overcomes the drawbacks of the adders from the literature and successfully reduces area, power dissipation and propagation delay.

Details

Engineering Computations, vol. 31 no. 2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 3 April 2018

Hyung-won Kim, Hyeim Jeong, Junho Yu, Chan-Soo Lee and Nam-Soo Kim

This paper aims to propose a low-power complementary MOS (CMOS) current sensor for control circuit in an integrated DC-DC buck converter.

Abstract

Purpose

This paper aims to propose a low-power complementary MOS (CMOS) current sensor for control circuit in an integrated DC-DC buck converter.

Design/methodology/approach

The integrated DC-DC converter, which is composed of feedback control circuit and power block, is designed with 0.35-µm CMOS process. Current sensor in the control circuit is integrated with sense-FET and voltage-follower circuits to reduce power consumption and improve its sensing accuracy. In the current-sensing circuit, the size ratio of the power metal oxide semiconductor field effect transistor (MOSFET) to the sensing transistor (K) is 1,000, and a current-mirror is used for a voltage follower. N-channel MOS acts as a switching device in the current-sensing circuit, where the sensing FET is in parallel with the power MOSFET. The amplifier and comparator are designed to obtain a high gain and a fast transient time.

Findings

Experiment shows that the current sensor is operated with accuracy of more than 85 per cent, and the transient time of the error amplifier is controlled within 100 µs. The sensing current is in the range of a few hundred µA at a frequency of 0.6-2 MHz and an input voltage of 3-5 V. The output voltage is obtained as expected with the ripple ratio within 5 per cent.

Originality/value

The proposed current sensor in DC-DC converter provides an accurately sensed inductor current with a significant reduction in power consumption in the range of 0.2 mW. High-accuracy regulation is obtained using the proposed current sensor. As the sensor utilizes simple switch-type voltage follower and sense-FET, it can be widely applied to other low-power applications such as high-frequency oscillator and over-current protection circuit.

Details

Microelectronics International, vol. 35 no. 2
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 28 January 2020

Neethu Anna Sabu and Batri K.

This paper aims to design three low-power and area-efficient serial input parallel output (SIPO) register designs, namely, transistor count reduction technique shift…

Abstract

Purpose

This paper aims to design three low-power and area-efficient serial input parallel output (SIPO) register designs, namely, transistor count reduction technique shift register (TCRSR), series stacking in TCR shift register (S-TCRSR) and forced stacking of transistor in TCR shift register (FST in TCRSR). Shift registers (SR) are the basic building blocks of all types of digital applications. The performance of all the designs has been improved through one of the metaheuristic algorithms named elephant herding optimization (EHO) algorithm and hence suited for low-power very large scale integration (VLSI) applications. It is for the first time that the EHO algorithm is implemented in memory elements.

Design/methodology/approach

The registers together with clock network consume 18-36 percentage of the total power consumption of a microprocessor. The proposed designs are implemented using low-power and high-performance double edge-triggered D flip-flops with least count of clocked transistors involving transmission gate. The second and third register designs are developed from the modified version of the first one employing series and forced stacking, thereby reducing static power because of sub-threshold leakage current. The performance parameters such as power-delay-product (PDP) and leakage power are further optimized using the EHO algorithm. A greater reduction in power is achieved in all the designs by utilizing the EHO algorithm.

Findings

All the designs are simulated at a supply voltage of 1 V/500 MHz when the input switching activity is 25 percentage in Cadence Virtuoso using 45 nm CMOS technology. Nine recently proposed SR designs are simulated in the same conditions, and the performance has been compared with the proposed ones. The simulated results prove the excellence of proposed designs in different performance parameters like leakage power, energy-delay-product (EDP), PDP, layout area compared with the recent designs. The PDPdq value has a reduction of 95.9per cent (TCRSR), 96.6per cent (S-TCRSR) and 97per cent (FST in TCRSR) with that of a conventional shift register (TGSR).

Originality/value

The performance of proposed low-power SR designs is enhanced using EHO algorithm. The optimized performance results have been compared with a few optimization algorithms. It is for the first time that EHO algorithm is implemented in memory elements.

Details

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

Keywords

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Article
Publication date: 3 February 2020

Hamidreza Ghanbari Khorram and Alireza Kokabi

Several ultra-low power and gigahertz current-starved voltage-controlled oscillator (CSVCO) circuits have been proposed and compared here. The presented structures are…

Abstract

Purpose

Several ultra-low power and gigahertz current-starved voltage-controlled oscillator (CSVCO) circuits have been proposed and compared here. The presented structures are based on the three-stage hybrid circuit of the carbon nanotube field-effect transistors (CNTFETs) and low-power MOSFETs. The topologies exploit modified and compensated Schmitt trigger comparator parts to demonstrate better consumption power and frequency characteristics. The basic idea in the presented topologies is to compensate the Schmitt trigger comparator part of the basic CSVCO for achieving faster carrier mobility of the holes, reducing transistor leakage current and eliminating dummy transistors.

Design/methodology/approach

This study aims to propose and compare three different comparator-based VCOs that have been implemented using the CNTFETs. The considered circuits are shown to be capable of delivering the maximum 35 tuning frequency in the order of 1 GHz to 5 GHz. A major power thirsty part of the high-frequency ring VCOs is the Schmitt trigger stage. Here, several fast and low-power Schmitt trigger topologies are exploited to mitigate the dissipation power and enhance the oscillation frequency.

Findings

As a result of proposed modifications, more than one order of magnitude mitigation in the VCO power consumption with respect to the previously presented three-stage CSVCO is reported here. Thus, a VCO dissipation power of 3.5 µW at the frequency of 1.1 GHz and the tuning range of 26 per cent is observed for the well-established 32 nm technology and the supply voltage of 1 V. Such a low dissipation power is obtained around the operating frequency of the battery-powered cellular phones. In addition, using the p-carrier mobility compensation and enhancing the rise time of the Schmitt trigger part of the CSVCO, a maximum of 2.38 times higher oscillation frequency and 72 per cent wider tuning range with respect to Rahane and Kureshi (2017) are observed. Simultaneously, this topology exhibits an average of 20 per cent reduction in the power consumption.

Originality/value

Several new VCO topologies are presented here, and it is shown that they can significantly enhance the power dissipation of the GHz CSVCOs.

Details

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

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Article
Publication date: 26 March 2021

Abhay Sanjay Vidhyadharan and Sanjay Vidhyadharan

Tunnel field effect transistors (TFETs) have significantly steeper sub-threshold slope (24–30 mv/decade), as compared with the conventional metal–oxide–semiconductor…

Abstract

Purpose

Tunnel field effect transistors (TFETs) have significantly steeper sub-threshold slope (24–30 mv/decade), as compared with the conventional metal–oxide–semiconductor field-effect transistors (MOSFETs), which have a sub-threshold slope of 60 mv/decade at room temperature. The steep sub-threshold slope of TFETs enables a much faster switching, making TFETs a better option than MOSFETs for low-voltage VLSI applications. The purpose of this paper is to present a novel hetero-junction TFET-based Schmitt triggers, which outperform the conventional complementary metal oxide semiconductor (CMOS) Schmitt triggers at low power supply voltage levels.

Design/methodology/approach

The conventional Schmitt trigger has been implemented with both MOSFETs and HTFETs for operation at a low-voltage level of 0.4 V and a target hysteresis width of 100 mV. Simulation results have indicated that the HTFET-based Schmitt trigger not only has significantly lower delays but also consumes lesser power as compared to the CMOS-based Schmitt trigger. The limitations of the conventional Schmitt trigger design have been analysed, and improved CMOS and CMOS–HTFET hybrid Schmitt trigger designs have been presented.

Findings

The conventional Schmitt trigger implemented with HTFETs has 99.9% lower propagation delay (29ps) and 41.2% lesser power requirement (4.7 nW) than the analogous CMOS Schmitt trigger, which has a delay of 36 ns and consumes 8 nW of power. An improved Schmitt trigger design has been proposed which has a transistor count of only six as compared to the eight transistors required in the conventional design. The proposed improved Schmitt trigger design, when implemented with only CMOS devices enable a reduction of power delay product (PDP) by 98.4% with respect to the CMOS conventional Schmitt trigger design. The proposed CMOS–HTFET hybrid Schmitt trigger further helps in decreasing the delay of the improved CMOS-only Schmitt trigger by 70% and PDP by 21%.

Originality/value

The unique advantage of very steep sub-threshold slope of HTFETs has been used to improve the performance of the conventional Schmitt trigger circuit. Novel CMOS-only and CMOS–HTFET hybrid improved Schmitt trigger designs have been proposed which requires lesser number of transistors (saving 70% chip area) for implementation and has significantly lower delays and power requirement than the conventional designs.

Details

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

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Article
Publication date: 2 January 2018

Pragash Sangaran, Narendra Kumar, Jagadheswaran Rajendran and Andrei Grebennikov

This paper aims to propose a practical design methodology of high-power wideband power amplifier.

Abstract

Purpose

This paper aims to propose a practical design methodology of high-power wideband power amplifier.

Design/methodology/approach

The distributed power amplification method is used for a Gallium Nitride device to achieve wideband operation. To achieve the high power without trading-off the bandwidth and gain, a methodology to extract the package-loading effect is proposed and verified.

Findings

A maximum output power of 10 W is achieved from 100 MHz to 2 GHz with a wideband power gain of 32 dB in measurement. This performance is achieved through a single section matching network.

Research limitations/implications

Measurement accuracy is dependable to the thermal behaviour of the high-power device.

Practical implications

The proposed technique is an excellent solution to be used in the two way radio power amplifier that minimizes the fundamental trade-off issue between power, gain, bandwidth and efficiency.

Originality/value

In this work, a practical distributed power amplifier (DPA) design methodology is proposed that reduces the development cycle time for industrial engineers working on high-power circuit design application.

Details

Microelectronics International, vol. 35 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 7 August 2017

Krzysztof Górecki and Paweł Górecki

This paper aims to propose the electrothermal dynamic model of the insulated gate bipolar transistors (IGBT) for SPICE.

Abstract

Purpose

This paper aims to propose the electrothermal dynamic model of the insulated gate bipolar transistors (IGBT) for SPICE.

Design/methodology/approach

The electrothermal model of this device (IGBT), which takes into account both electrical and thermal phenomena, is described. Particularly, the sub-threshold operation of this device is considered and electrical, and thermal inertia of this device is taken into account. Attention was focused on the influence of electrical and thermal inertia on waveforms of terminal voltages of the considered transistor operating in the switching circuit and on waveforms of the internal temperature of this device.

Findings

The correctness of the presented model is verified experimentally and a good agreement of the calculated and measured electrical and thermal characteristics of the considered device is obtained.

Research limitations/implications

The presented model can be used for different types of IGBT, but it is dedicated for SPICE software only.

Originality/value

The form of the worked out model is presented and the results of experimental verification of this model are shown.

Details

Microelectronics International, vol. 34 no. 3
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 1 February 1995

P.A. Mawby, J. Zeng and K. Board

Poisson’s equation and the electron continuity equation, together withheat flow equation are solved self‐consistently to obtain the latticetemperature profile under…

Abstract

Poisson’s equation and the electron continuity equation, together with heat flow equation are solved self‐consistently to obtain the lattice temperature profile under non‐isothermal conditions in a power VDMOS transistor. The effect of the variable lattice temperature on the forward characteristics of VDMOSTs is presented, and discussed. The results show that self‐heating in power VDMOSTs has a significant effect. The thermal coupling effects on the forward I—V characteristics are compared and discussed between the power VDMOST and the conventional MOSFET.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 5 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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