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capacitor-charging
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An efficient fast switching procedure for stepwise capacitor chargers
, Article IEEE Transactions on Very Large Scale Integration (VLSI) Systems ; Volume 25, Issue 2 , 2017 , Pages 705-713 ; 10638210 (ISSN) ; Sharifkhani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
A new low-power switching procedure for stepwise capacitor chargers is presented. In this procedure, a novel displacement method is utilized to improve the speed by a factor of two while preserving energy efficiency. Moreover, the load capacitor retains its charge after the charging process finishes and permits the circuit charge another predischarged load capacitor without an efficiency degradation problem (instability). Also, the control circuit of the switching procedure is implemented using only flip-flops with no combinational logic, therefore, it systematically prevents glitch power dissipation and improves the efficiency. Analytical derivations are proposed to model the switching...
Artificial neural network simulator for supercapacitor performance prediction
, Article Computational Materials Science ; Volume 39, Issue 3 , 2007 , Pages 678-683 ; 09270256 (ISSN) ; Gobal, F ; Sharif University of Technology
2007
Abstract
Artificial neural network was used to calculate the performance of a model supercapacitor as signified by the power density, energy density and utilization to the synthetic, intrinsic and operating characteristics. A four-layer neural net having two hidden layers having 6 and 15 nodes was found to be well capable of simulating the capacitor performance with the convergence achieved often a relatively small number of epochs. As for the input parameters, crystal size, surface lattice length, exchange current density of the capacitor active material and the cell current employed while utilization, energy density and power density were the outputs. © 2006 Elsevier B.V. All rights reserved
An efficient fast switching procedure for stepwise capacitor chargers
, Article IEEE Transactions on Very Large Scale Integration (VLSI) Systems ; Volume PP, Issue 99 , 2016 ; 10638210 (ISSN) ; Sharifkhani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
A new low-power switching procedure for stepwise capacitor chargers is presented. In this procedure, a novel displacement method is utilized to improve the speed by a factor of two while preserving energy efficiency. Moreover, the load capacitor retains its charge after the charging process finishes and permits the circuit charge another predischarged load capacitor without an efficiency degradation problem (instability). Also, the control circuit of the switching procedure is implemented using only flip-flops with no combinational logic, therefore, it systematically prevents glitch power dissipation and improves the efficiency. Analytical derivations are proposed to model the switching...
Behavioral modeling of clock feed-through and channel charge injection non-ideal effects in SIMULINK for switched-capacitor integrator
, Article Simulation Modelling Practice and Theory ; Volume 18, Issue 5 , May , 2010 , Pages 483-499 ; 1569190X (ISSN) ; Atarodi, M ; Sharif University of Technology
2010
Abstract
Sigma-Delta modulator ADCs used in signal processing applications usually, are implemented by switched-capacitor (SC) circuits and CMOS transmission gates due to its simplicity for implementation. Channel charge injection (CCI) and clock feed-through (CFT) are two major non-ideal effects existing in TG switches and SC integrators reducing modulator total SNR, its linearity and its total gain. This paper presents a precise model for SC integrator including CCI and CFT non-ideal effects in MATLAB SIMULINK environment which allows designers to perform time-domain behavioral simulations of switched-capacitor (SC) Sigma-Delta modulators. Evaluation and validation of extracted models were...
In-situ electrochemical exfoliation of Highly Oriented Pyrolytic Graphite as a new substrate for electrodeposition of flower like nickel hydroxide: Application as a new high-performance supercapacitor
, Article Electrochimica Acta ; Volume 206 , 2016 , Pages 317-327 ; 00134686 (ISSN) ; Mohammadi, R ; Amini, M. K ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Demand for more efficient energy storage devices stimulates efforts to search and develop new materials and composites with promising properties. In this regard, composite materials, including carbonaceous materials and metal oxides have attracted a great attention due to better electrochemical performance as compared to their single material analogues. For the first time, herein, we report a new and simple procedure for preparing porous highly oriented pyrolytic graphite/nickel hydroxide composite (P-HOPG/Ni(OH)2) via a fast and simple two-step electrochemical method including potentiostatic routes. In the first step, a low anodic potential (2 V) was applied to pristine HOPG in 0.5 M H2SO4...
Energy consumption analysis of the stepwise adiabatic circuits
, Article Microelectronics Journal ; Volume 104 , October , 2020 ; Saeidi, R ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this paper, an analytic model of the energy consumption of the Stepwise Adiabatic Circuits (SAC) when it is possible to discharge the load capacitor is proposed. Using this model, analytical derivations are calculated which shows us the power saving of the SACs. Using analytical derivations, the sizing of a capacitor tank is determined for a desired energy saving. For example, the derivations predict that if the sizing of the 3-step series tank capacitors is equal to the load capacitor, the power saving is 55%. Also, if the sizing of the tank is very large the energy saving of a 3-step stepwise charging is equal to 66.7%. Several Simulations in 0.18μm CMOS technology prove the accuracy of...
Hardware Design for Cold Plasma Characterization Chamber
, M.Sc. Thesis Sharif University of Technology ; Rashidian, Bijan (Supervisor) ; Faez, Rahim (Supervisor)
Abstract
Cold plasma due to its special properties has many applications in the microelectronics industry. At the beginning of this study, a few examples of widely used plasmas and the requirements for driving their power sources have been investigated. To generate and characterize plasma, various topologies of DC power supply construction, including high-voltage low-current power supplies called multipliers and low-voltage high-voltage power supplies called converters, have been reviewed and compared.Circuit for pulse generating for plasma application has also been proposed and investigated. In the simulation section, after introducing, reviewing, and compareing the common types of simulators, the...
Fabrication of nanoporous nickel oxide by de-zincification of Zn-Ni/(TiO2-nanotubes) for use in electrochemical supercapacitors
, Article Electrochimica Acta ; Volume 100 , 2013 , Pages 133-139 ; 00134686 (ISSN) ; Faraji, M ; Sharif University of Technology
2013
Abstract
NiO-ZnO/TiO2NTs electrodes were synthesized by the electrodeposition of Zn-Ni onto TiO2 nanotubes, dealloying in a concentrated alkaline solution and finally calcination of the resulting Zn(OH)2-Ni(OH)2/TiO2NTs at 300 C. Morphology of the electrodeposited nanostructures was studied using scanning electron microscopy (SEM) while their electrochemical characterizations were carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge procedures. The SEM analysis revealed the nanoporous/cracked structures of the NiO-ZnO/TiO2NTs obtained at the electroplating time of 20 min. The EIS studies showed that nanoporous/cracked structures of...
Electrodeposited polyaniline on Pd-loaded TiO2 nanotubes as active material for electrochemical supercapacitor
, Article Journal of Electroanalytical Chemistry ; Volume 691 , 2013 , Pages 51-56 ; 15726657 (ISSN) ; Faraji, M ; Sharif University of Technology
2013
Abstract
PANI/Pd/TiO2NTs electrodes with highly porous structures and good capacitive characteristics were prepared by electrodeposition of polyaniline on palladium nanoparticles loaded TiO2 nanotubes. The loading of small palladium nanoparticles was carried out by sonochemical reduction of Pd+2 onto TiO2NTs and affected the ordered growth of PANI, reducing the charge transfer resistance and increasing surface area of PANI. The specific capacitance and the stability of electrode showed improvements. The results illustrated that the specific capacitance of these electrodes was around 1060 F g-1 in 1.0 M H2SO4 electrolyte as measured at a constant current of 2.0 A g-1, whereas it was 210 F g-1 for the...
A study of hydrated nanostructured tungsten trioxide as an electroactive material for pseudocapacitors
, Article Ionics ; Volume 19, Issue 2 , May , 2013 , Pages 287-294 ; 09477047 (ISSN) ; Gobal, F ; Barzgari, Z ; Sharif University of Technology
2013
Abstract
Agglomerates of tungsten trioxide in the range of 90 nm to 1 μm are prepared by the acid precipitation method and characterized by XRD as well as scanning electron microscopy. The product when coated with platinum showed pseudocapacitance when in contact with acidic electrolyte in the potential range of 0. 1 to -0. 25 V/SCE. Capacitance in the range of 0. 014 to 0. 039 F cm-2 exhibiting moderate potential dependencies measured through both chronopotentiometry and impedance spectroscopy is presumed to be due to the insertion/de-insertion of protons into the lattice of tungsten trioxide. Equivalent circuit consisting of parallel simulators of mass transfer and capacitor charging...
General Characterization Method and a Fast Load-Charge-Preserving Switching Procedure for the Stepwise Adiabatic Circuits
, Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 63, Issue 1 , 2016 , Pages 80-90 ; 15498328 (ISSN) ; Sharifkhani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
An analytical method is presented to characterize stepwise adiabatic circuits (SACs). In this method, the SACs are modeled as a discrete time system. Unlike previous methods, the stability is verified for arbitrary load capacitor ratios. Moreover, this method presents analytical derivations to offer an area/energy efficient design methodology. MATLAB simulations, post-layout simulations in the CMOS 0.18 μm technology, silicon measurements, and measurements based on discrete components confirm the precision of the analytical derivations. Using the proposed design methodology, a capacitive tank has been designed which reduces the energy consumption by 20% while the total size of the tank...
CHANCE: Capacitor charging management scheme in energy harvesting systems
, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; 2020 ; Bahrami, M. R ; Ejlali, A ; Abam, M. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
The energy efficiency of emerging nonvolatile processors equipped with FRAM-SRAM memory makes them a promising solution for energy harvesting systems. To enable correct functionality and forward progress with an unreliable power supply, the system must accumulate sufficient energy in the capacitor to execute tasks atomically, even in the worst case scenario. Due to the large gap between the average and worst case energy consumption of tasks, state of the art approaches like eM-map require a large capacitor to execute tasks on the SRAM. However, the size, cost, and charging time of the capacitor are major concerns in the energy harvesting systems. In this paper, we proposed CHANCE, a...
CHANCE: Capacitor charging management scheme in energy harvesting systems
, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; Volume 40, Issue 3 , June , 2021 , Pages 419-429 ; 02780070 (ISSN) ; Bahrami, M. R ; Ejlali, A ; Abam, M. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
The energy efficiency of emerging nonvolatile processors equipped with FRAM-SRAM memory makes them a promising solution for energy harvesting systems. To enable correct functionality and forward progress with an unreliable power supply, the system must accumulate sufficient energy in the capacitor to execute tasks atomically, even in the worst case scenario. Due to the large gap between the average and worst case energy consumption of tasks, state-of-the-art approaches like eM-map require a large capacitor to execute tasks on the SRAM. However, the size, cost, and charging time of the capacitor are major concerns in the energy harvesting systems. In this article, we proposed CHANCE, a...