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Article
Publication date: 31 December 2021

Alperen Pekdemir and Ali Bekir Yildiz

This paper aims to propose a new unified and non-ideal switch model for analysis of switching circuits.

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Abstract

Purpose

This paper aims to propose a new unified and non-ideal switch model for analysis of switching circuits.

Design/methodology/approach

The model has a single unified structure that includes all possible states (on, off) of the switches. The analysis with the proposed switch model requires only one topology and uses the single system equation regardless of states of switches. Moreover, to improve accuracy, the model contains the on-state resistance and capacitive effect of switches. The system equations and the states of switches are updated by control variables, used in the model.

Findings

There are no restrictions on circuit topology and switch connections. Switches can be internally and externally controlled. The non-ideal nature of the model allows the switch to be modeled more realistically and eliminates the drawbacks of the ideal switch concept. After modeling with the proposed switch model, a linear circuit is obtained. Two examples related to switching circuits are included into the study. The results confirm the accuracy of the model.

Originality/value

This paper contributes a different switch model for analysis of switching converters to the literature. The main advantage of the model is that it has a unified and non-ideal property. With the proposed switch model, the transient events, like voltage spikes and high-frequency noises, caused by inductor and capacitor elements at switching instants can be observed properly.

Details

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

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Article
Publication date: 12 August 2021

Guoda Wang, Ping Li, Yumei Wen and Zhichun Luo

Existing control circuits for piezoelectric energy harvesting (PEH) suffers from long startup time or high power consumption. This paper aims to design an ultra-low power…

Abstract

Purpose

Existing control circuits for piezoelectric energy harvesting (PEH) suffers from long startup time or high power consumption. This paper aims to design an ultra-low power control circuit that can harvest weak ambient vibrational energy on the order of several microwatts to power heavy loads such as wireless sensors.

Design/methodology/approach

A self-powered control circuit is proposed, functioning for very brief periods at the maximum power point, resulting in a low duty cycle. The circuit can start to function at low input power thresholds and can promptly achieve optimal operating conditions when cold-starting. The circuit is designed to be able to operate without stable DC power supply and powered by the piezoelectric transducers.

Findings

When using the series-synchronized switch harvesting on inductor circuit with a large 1 mF energy storage capacitor, the proposed circuit can perform 322% better than the standard energy harvesting circuit in terms of energy harvested. This control circuit can also achieve an ultra-low consumption of 0.3 µW, as well as capable of cold-starting with input power as low as 5.78 µW.

Originality/value

The intermittent control strategy proposed in this paper can drastically reduce power consumption of the control circuit. Without dedicated cold-start modules and DC auxiliary supply, the circuit can achieve optimal efficiency within one input cycle, if the input signal is larger than voltage threshold. The proposed control strategy is especially favorable for harvesting energy from natural vibrations and can be a promising solution for other PEH circuits as well.

Details

Circuit World, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 21 January 2022

Mazdak Ebadi, Negin Abbasi and Hamidreza Maghsoudi

This paper aims to propose an integrated protection scheme for converters of a low-power, low-cost photovoltaic system. Power electronic converters use a variety of…

Abstract

Purpose

This paper aims to propose an integrated protection scheme for converters of a low-power, low-cost photovoltaic system. Power electronic converters use a variety of methods to limit overload and fault current. The use of insulated and non-insulated sensors along with additional circuits to detect and limit fault current can cause current to be limited or completely cut off before damage to semiconductor devices. In addition, fuses that have slower performance are used as backup for any type of protection.

Design/methodology/approach

First, all the candidate points for protection are investigated. In this paper, after examining the performance of glass fuses as linear resistors, they are used as a current feedback element. A simple, isolated and reliable circuit for fault detection at various points of the system has been proposed that can be implemented and operated in single shot or auto-reclose operating mode.

Findings

The experimental results of this circuit on a dc/dc converter and an H-bridge inverter show that it can cut off all instantaneous short circuit errors in less than 50 µs and prevent damage to the semiconductor switch.

Originality/value

In low-cost and low-power converters, it is usually not cost-effective to use complex and expensive devices. For this reason, these converters are more vulnerable to faults. On the other hand, in complex systems such as photovoltaics, several converters are used simultaneously in different parts, and the occurrence of a fault in each of them causes the whole system to fail.

Details

Circuit World, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 26 January 2022

Rawid Banchuin

The purpose of this study is to originally present noise analysis of electrical circuits defined on fractal set.

Abstract

Purpose

The purpose of this study is to originally present noise analysis of electrical circuits defined on fractal set.

Design/methodology/approach

The fractal integrodifferential equations of resistor-inductor, resistor-capacitor, inductor-capacitor and resistor-inductor-capacitor circuits subjected to zero mean additive white Gaussian noise defined on fractal set have been formulated. The fractal time component has also been considered. The closed form expressions for crucial stochastic parameters of circuit responses have been derived from these equations. Numerical simulations of power spectral densities based on the derived autocorrelation functions have been performed. A comparison with those without fractal time component has been made.

Findings

We have found that the Hausdorff dimension of the middle b Cantor set strongly affects the power spectral densities; thus, the average powers of noise induced circuit responses and the inclusion of fractal time component causes significantly different analysis results besides the physical measurability of electrical quantities.

Originality/value

For the first time, the noise analysis of electrical circuit on fractal set has been performed. This is also the very first time that the fractal time component has been included in the fractal calculus-based circuit analysis.

Details

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

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Article
Publication date: 1 March 1989

F.W. Haining, R.F. Shaul, R.W. Keim and R.M. Murcko

The circuit elements of every printed circuit board have the potential for failure during test and/or use. These failures can occur by forming short‐circuits between…

Abstract

The circuit elements of every printed circuit board have the potential for failure during test and/or use. These failures can occur by forming short‐circuits between adjacent circuit elements, or by forming open‐circuits in the conductors. The risk sites can be identified by type, and the total number enumerated by manual inspection of the photolithographic masks used to fabricate the printed circuit layers. However, the circuit density of high performance printed circuit boards has become so great that meaningful manual analysis has become impractical. A more effective method is to use special graphics programs to analyse the computer‐aided design (CAD) data. The methodology developed to perform the CAD analysis of high performance printed circuit boards for short‐circuits utilises two powerful computer graphic tools: the Interactive Graphics System and the Unified Shapes Checking system. Test data for open‐circuits are generated using specially written alphanumeric routines. The data can be used for stress testing the printed circuit boards by wiring up special test modules that are plugged into the boards and then placing the boards into environmental test chambers. The printed circuits are checked for short‐circuits by putting them into groups that have no risk of shorting to each other (zero risk), and placing the groups in parallel under an electrical potential. The flow of current between the groups would indicate a short‐circuit. Similarly, the printed circuits can be checked for open‐circuits, by stringing them together into groups in series, and measuring the changes in resistance under thermal stress. Both types of test data can also be used for in‐process testing.

Details

Circuit World, vol. 15 no. 4
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 1 May 2006

Markus Wille

Seeks to answer the question: have the reasons for using flex‐rigid circuit boards changed through the years?

Abstract

Purpose

Seeks to answer the question: have the reasons for using flex‐rigid circuit boards changed through the years?

Design/methodology/approach

The paper presents the development of flex‐rigid circuit board construction techniques from the first applications to the current status of a modern interconnection system. The paper discusses that it was the military and avionic industry that in the past required an interconnection technique that was reliable under environmental stress but compact and lightweight. Today it is the automotive and communication industry that is driving the development of printed circuit board technology.

Findings

Finds that wiring and interconnection must be cheap, reliable, light in weight, and must fit into very small housings. The demand for complex interconnection solutions like the flex‐rigid circuit technique is rising with the increased level of integration of more functions into electronic devices. The reasons for using flex‐rigid circuitries are nearly still the same as in the beginning.

Originality/value

Shows how the flex‐rigid circuit board technology has developed during the last 30 years.

Details

Circuit World, vol. 32 no. 2
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 1 February 1989

R. Gee and M.V. Coleman

The environmental reliability of Series Q, a system of materials designed for advanced ‘HIC’ circuits, has been studied using three different migration‐resistance tests…

Abstract

The environmental reliability of Series Q, a system of materials designed for advanced ‘HIC’ circuits, has been studied using three different migration‐resistance tests. —LMRT: a test which is used to assess the resistance to electrochemical migration of horizontally adjacent, closely spaced conductor tracks in a high‐temperature, high‐humidity environment with a voltage bias present (60°C, 90%RH, 48 VDC). —HHBT: a test which monitors the ability of a dielectric to resist electrochemical migration when vertically adjacent crossover conductor tracks are oppositely biased (85°C, 85%RH, 5 VDC). —HBT: a test which measures how well a dielectric can sustain its resistance to voltage breakdown over extended periods of time during continuous exposure to conditions of high temperature and voltage (150°C, 200 VDC). The results show that the QSil™ and QPIus™ systems, the two materials systems that comprise Series Q, demonstrate excellent performance in all three areas. Predictions of how well circuits made from these materials will survive in their operating ambient over the long term, e.g., twenty years, have been made.

Details

Microelectronics International, vol. 6 no. 2
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 1 February 1986

S. Gazit

The increasing use of high switching speed systems in both microwave electronics and high speed logic devices has created the need for printed circuit boards which are…

Abstract

The increasing use of high switching speed systems in both microwave electronics and high speed logic devices has created the need for printed circuit boards which are based on low dielectric constant and low loss materials. In addition, these circuit materials must be capable of withstanding elevated temperatures typical of hostile service environments and of board fabrication processes. Such low dielectric constant rigid boards are commercially available from a few sources. However, there is a growing demand for low dielectric constant flexible printed circuit boards for interconnecting rigid boards or in rigid/flex applications where high speed, fast rise times, controlled impedance and low crosstalk are important. A new family of thin laminates which are suitable for fabrication of flexible low dielectric constant printed circuit boards have been developed by Rogers Corporation. These circuit materials are called ROhyphen;2500 laminates and offer flexible interconnections in high speed electronic systems. RO‐2500 circuit materials are based on microglass reinforced fluorocarbon composites and have a typical dielectric constant of 25. The transmission line properties of these materials have been evaluated by the IPC‐FC‐201 test method. The results indicated that these circuit materials improve the propagation velocity by about 10% and the rise time by about 30% when compared with the same geometry, polyimide film based, flexible PCs in stripline constructions. Also, dimensional stability of these laminates after etch and heat ageing is improved over that of the standard flex circuit materials based on polyimide film. RO‐2500 laminate properties have been evaluated by the IPC‐TM‐650 test methods, which are widely accepted by the flexible PCB industry.

Details

Circuit World, vol. 12 no. 3
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 7 November 2016

Toshihito Shimotani, Yuki Sato and Hajime Igarashi

The purpose of this paper is to propose a fast synthesis method of the equivalent circuits of electromagnetic devices using model order reduction. Finite element method…

Abstract

Purpose

The purpose of this paper is to propose a fast synthesis method of the equivalent circuits of electromagnetic devices using model order reduction. Finite element method (FEM) has been widely used to design electromagnetic devices. For FE analysis of these devices connected to control and deriving circuits, FE equations coupled with the circuit equations have to be solved for many times in their design processes. If the FE models are replaced by equivalent circuit models, computational time could be drastically reduced.

Design/methodology/approach

In the proposed method, a reduced FE model is obtained using proper orthogonal decomposition (POD) in which the size of FE equation is effectively reduced so that the computational time for FE analysis is shortened. Then, the equivalent circuits are directly synthesized from the admittance function of the reduced system.

Findings

Accuracy and computational efficiency of the proposed method are compared with those of another POD-based method in which the equivalent circuits are synthesized from fitting of frequency characteristics using optimization algorithm. There are no significant differences in the accuracy of both methods, while the speedup ratio of the former method is found larger than that for the latter method for the same sampling points.

Originality/value

The equivalent circuits of electric machines and devices have been synthesized on the basis of physical insight of engineers. This paper proposes a novel method by which the equivalent circuits are automatically synthesized from FE model of the electric machines and devices using POD.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 35 no. 6
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 25 July 2008

A. Marzuki, Zaliman Sauli, Ali Yeon and Shakaff

The purpose of this paper is to design a voltage reference circuit for current source of radio frequency integrated circuit blocks. The voltage reference circuit is called…

Abstract

Purpose

The purpose of this paper is to design a voltage reference circuit for current source of radio frequency integrated circuit blocks. The voltage reference circuit is called voltage for current source (VCS).

Design/methodology/approach

The circuit concept is discussed. A voltage‐controlled oscillator (VCO) and buffer circuit together with VCS circuit are built to prove the concept. Though the VCS circuit employs no array of diode like standard bandgap circuit, it still employs the concept of proportional to absolute temperature (PTAT) and a complement to absolute temperature (CTAT) elements. The integrated VCO, together with VCO core and VCO buffer circuits, are designed for W‐CDMA application particularly for the demodulator section. All circuits are built in fT=45 GHz SiGe BiCMOS process.

Findings

At 760 MHz the power consumption for core circuit is 0.6 and 3.3 mA for VCO buffer amplifier. The fabricated VCO circuit together with VCO buffer was tested and measured with VCO output of −6 dBm at 760 MHz with variation of 0.1 dBm across −40°C to 85°C.

Originality/value

A voltage reference circuit which is derived from PTAT and CTAT current generators is presented. The circuit is capable of providing a constant current across absolute temperature or a current PTAT.

Details

Microelectronics International, vol. 25 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

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