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Article
Publication date: 1 January 2014

Jung Woong Park, Munkhsuld Gendensuren, Ho-Yong Choi and Nam-soo Kim

– The paper aims to design of dual-mode boost converter with integrated low-voltage control circuit is introduced in this paper. The paper aims to discuss these issues.

Abstract

Purpose

The paper aims to design of dual-mode boost converter with integrated low-voltage control circuit is introduced in this paper. The paper aims to discuss these issues.

Design/methodology/approach

The converter is operated either with LC filter or with charge pump circuit by the switch control. The control stage with error amplifier, comparator, and oscillator is designed with the supply voltage of 3.3 V and the operating frequency of 5.5 MHz. The compensator circuit exploits a pole compensation for a stable operation.

Findings

The simulation test in 0.35 μm CMOS process shows that the charge pump regulator and DC-DC boost converter are accurately controlled with the variation of number of stages and duty ratio. The output-voltage is obtained to be 6-15 V within the ripple ratio of 5 percent. Maximum power consumption is about 0.65 W.

Originality/value

This dual-mode is useful in the converter with a wide load-current variation. The advantage of the dual-mode converter is that it can be used in either high or low load current with a simple switch control. Furthermore, in charge pump regulator, there is no degradation of output voltage because of the feedback control circuit.

Details

Microelectronics International, vol. 31 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 1 March 1974

THE CONSTANT SPEED DRIVES supplied by Sundstrand which convert the variable speed of a jet engine into a constant speed to drive a 400Hz constant frequency electric…

Abstract

THE CONSTANT SPEED DRIVES supplied by Sundstrand which convert the variable speed of a jet engine into a constant speed to drive a 400Hz constant frequency electric generator to provide power for an aircraft's electrical system were first introduced in 1945 and allowed aircraft to use a lighter weight, more economical, and more reliable ac generating system.

Details

Aircraft Engineering and Aerospace Technology, vol. 46 no. 3
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 February 1963

J.T. CHAPMAN

THE transportation of material in bulk containers over the past few years has increased until the variety of loads carried is infinite, indeed even the casual road user…

Abstract

THE transportation of material in bulk containers over the past few years has increased until the variety of loads carried is infinite, indeed even the casual road user cannot have failed to notice the increasing numbers of tank carrying vehicles ; everything from concrete to flour is now accepted as normal. Labour is one of the heaviest charges in industry today and here perhaps is the main reason for the change ; handling any material by hand carries with it a premium in labour costs with loading and unloading and often double and treble handling. As is often the case when economic reasons cause readjustment of industrial methods other advantages also come to light, e.g. delivery of flour in bulk is cleaner and less wasteful than carrying in sacks. The same can be said for most other materials.

Details

Industrial Lubrication and Tribology, vol. 15 no. 2
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 14 June 2019

Amy Blitz and Khurram Kazi

This paper aims to set out a vision of the advent of autonomous electric vehicles (AEV), piloted by artificial intelligence and serviced by other “intelligent” machines, a…

Abstract

Purpose

This paper aims to set out a vision of the advent of autonomous electric vehicles (AEV), piloted by artificial intelligence and serviced by other “intelligent” machines, a scenario that poses vast implications for business strategy in many industries.

Design/methodology/approach

Given the speed with which business leaders today must assess and react to the business risks and opportunities engendered by breakthrough technological change, their plans to navigate an autonomous electric vehicle-based transportation future can benefit from a scenario map to the roadblocks and the richest prospects.

Findings

Self-driving electric cars and trucks, which are expected to transform the transportation landscape over the next decade. A smart charging grid is a critical technology development.

Practical implications

Business opportunities to transform ground transport in areas such as operations and supply chain management are significant as well, particularly with unsupervised AEVs, which could slash labor costs and transport times.

Social implications

AEVs are expected to free up more than 30 billion hours per year in the U.S. alone currently spent driving, sitting in traffic or searching for a parking space.

Originality/value

Offers a look at the technology evolution needed for the AEV transportation revolution.

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Article
Publication date: 1 April 1955

THE rapidly increasing electric power requirements of aircraft, together with their more arduous operating conditions, have accelerated the trend towards the adoption of…

Abstract

THE rapidly increasing electric power requirements of aircraft, together with their more arduous operating conditions, have accelerated the trend towards the adoption of 400 c.p.s. a.c. supplies as standard for general services. The point is being reached where a.c. distribution and control systems based on ground power station practice are becoming applicable to aircraft. The main advantages of a.c. over the corresponding d.c. systems are:

Details

Aircraft Engineering and Aerospace Technology, vol. 27 no. 4
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 14 August 2020

Vaithiyanathan D., Megha Singh Kurmi, Alok Kumar Mishra and Britto Pari J.

In complementary metal-oxide-semiconductor (CMOS) logic circuits, there is a direct square proportion of supply voltage on dynamic power. If the supply voltage is high…

Abstract

Purpose

In complementary metal-oxide-semiconductor (CMOS) logic circuits, there is a direct square proportion of supply voltage on dynamic power. If the supply voltage is high, then more amount of energy will be consumed. Therefore, if a low voltage supply is used, then dynamic power will also be reduced. In a mixed signal circuit, there can be a situation when lower voltage circuitry has to drive large voltage circuitry. In such a case, P-type metal-oxide-semiconductor of high-voltage circuitry may not be switched off completely by applying a low voltage as input. Therefore, there is a need for level shifter where low-voltage and high-voltage circuits are connected. In this paper the multi-scaling voltage level shifter is presented which overcomes the contention problems and suitable for low-power applications.

Design/methodology/approach

The voltage level shifter circuit is essential for digital and analog circuits in the on-chip integrated circuits. The modified voltage level shifter and reported energy-efficient voltage level shifter have been optimally designed to be functional in all process voltage and temperature corners for VDDH = 5V, VDDL = 2V and the input frequency of 5 MHz. The modified voltage level shifter and reported shifter circuits are implemented using Cadence Virtuoso at 90 nm CMOS technology and the comparison is made based on speed and power consumed by the circuit.

Findings

The voltage level shifter circuit discussed in this paper removes the contention problem that is present in conventional voltage level shifter. Moreover, it has the capability for up and down conversion and reduced power and delay as compared to conventional voltage level shifter. The efficiency of the circuit is improved in two ways, first, the current of the pull-up device is reduced and second, the strength of the pull-down device is increased.

Originality/value

The modified level shifter is faster for switching low input voltage to high output voltage and also high input voltage to low output voltage. The average power consumption for the multi-scaling voltage level shifter is 259.445 µW. The power consumption is very less in this technique and it is best suitable for low-power applications.

Details

World Journal of Engineering, vol. 17 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

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Article
Publication date: 7 August 2017

Miroslaw Gracjan Gierczak, Jacek Wróblewski and Andrzej Dziedzic

The paper focuses on design, fabrication and characterization of electromagnetic microgenerators with integrated rectifying circuits to convert AC output signal to DC one…

Abstract

Purpose

The paper focuses on design, fabrication and characterization of electromagnetic microgenerators with integrated rectifying circuits to convert AC output signal to DC one. The work includes research on simulation of voltage-rectifying circuits, including charge pump, realization of the experimental printed circuit board (PCB) with selected electronic circuits and the execution of the final structure with integrated rectifying circuit. Measurements were performed on these circuits.

Design/methodology/approach

Electromagnetic microgenerators include multipole permanent magnets secured on rotor three-phase brushless direct current (BLDC) motor and planar multilayer multiple coils. These were fabricated using low temperature co-fired ceramics (LTCC) technology. In our experiment, six rectifying circuits were simulated and tested with a structure consisting of eight layers of coils and with an outer diameter of 50 mm fabricated earlier.

Findings

The microgenerator with Graetz bridge generates higher output power than the modified charge pump at the same rotary speed. However, it is less stable for the distance change between the structure and the magnets than the modified charge pump, which has more constant output power in a wider range of load resistance.

Originality/value

The presented electronic rectifying circuits are novel for LTCC-based electromagnetic microgenerator application. The structure with integrated rectifying circuits allows generation of electrical output power larger than 100 mW at the rotor speed of about 8,000 rpm.

Details

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

Keywords

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Article
Publication date: 5 February 2018

Simona Di Fraia, Nicola Massarotti and P. Nithiarasu

This paper aims to provide a comprehensive literature review on modelling electro-osmotic flow in porous media.

Abstract

Purpose

This paper aims to provide a comprehensive literature review on modelling electro-osmotic flow in porous media.

Design/methodology/approach

Modelling electro-osmosis in fluid systems without solid particles has been first introduced. Then, after a brief description of the existing approaches for porous media modelling, electro-osmotic flow in porous media has been considered by analysing the main contributions to the development of this topic.

Findings

The analysis of literature has highlighted the absence of a universal model to analyse electro-osmosis in porous media, whereas many different methods and assumptions are used.

Originality/value

For the first time, the existing approaches for modelling electro-osmotic flow in porous have been collected and analysed to provide detailed indications for future works concerning this topic.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 1 April 1953

G.S. Bowey

There arc few published works dealing with British aircraft sanitary systems and associated equipment and a comprehensive survey of this particular subject should not…

Abstract

There arc few published works dealing with British aircraft sanitary systems and associated equipment and a comprehensive survey of this particular subject should not, therefore, be out of place here. In this article, a history of the development work culminating in the evolution of a modern scries of chemical closets is traced. It is shown that for equipment of this nature . simplicity of design is essential if proper mechanical functioning, satisfactory hygiene standards and good serviceability arc to be assured. Two outstanding features of the modern chemical closet are the closed flushing system, in which one of a scries of special chemical fluids is used as the circulating medium, and the external servicing arrangements. Specific closet design information is presented. Details arc also given of aircraft toilet compartment layout and of representative types of ground servicing equipment.

Details

Aircraft Engineering and Aerospace Technology, vol. 25 no. 4
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 January 2014

Vahideh Sadat Sadeghi and Hossein Miar Naimi

The linear analysis presented for the charge pump phase locked loops (CPPLLs) becomes inaccurate or incorrect where cycle slipping occurs. In this paper, an analytical…

Abstract

Purpose

The linear analysis presented for the charge pump phase locked loops (CPPLLs) becomes inaccurate or incorrect where cycle slipping occurs. In this paper, an analytical approach is proposed, which explains the conditions in which cycle slipping happens. Using the analytical results, one can simply design or redesign a CPPLL to prevent or decrease cycle slipping and hence decreasing the locking time. The paper aims to discuss these issues.

Design/methodology/approach

To obtain cycle slipping conditions, CPPLL's signals in the time domain are tracked and cycle slipping condition is investigated. Based on the proposed analysis, by comparing a simple function of system's parameters with a threshold, cycle slipping is predicted.

Findings

The cycle slipping conditions are expressed in terms of system's parameters and the size of the input frequency step. The method is also generalized for a fast CPPLL with an aid-lock BBFC circuit. The good accuracy of the analytical predictions is verified using simulations in Matlab/Simulink.

Originality/value

A new analytical method for cycle slipping prediction in CPPLLs is presented. A closed form equation in terms of system's parameters and input frequency step has been presented, which can predict the cycle slipping possibility in the system without a need to perform the full time-consuming simulations. This analytical method that uses the LambertW function's properties proposes a threshold to predict cycle slipping in the system. This method not only can be used by designers to predict cycle slipping but can also be used to design the CPPLL in order to remove or decrease cycle slipping. The method is also generalized for fast locking charge pump PLLs and as a case study, cycle slipping prediction in the BBFC-CPPLL is performed.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 33 no. 1/2
Type: Research Article
ISSN: 0332-1649

Keywords

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