scholarly journals Performance Analysis and Design Optimization of Parallel-Type Slew-Rate Enhancers for Switched-Capacitor Applications

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1949
Author(s):  
Alessandro Catania ◽  
Mattia Cicalini ◽  
Michele Dei ◽  
Massimo Piotto ◽  
Paolo Bruschi
Keyword(s):  
Power Efficiency ◽  
Settling Time ◽  
Current Gain ◽  
Design Parameters ◽  
Switched Capacitor ◽  
Slew Rate ◽  
Simple Modification ◽  
Analysis And Design ◽  
Time Reduction ◽  
Parallel Type

The design of single-stage OTAs for accurate switched-capacitor circuits involves challenging trade-offs between speed and power consumption. The addition of a Slew-Rate Enhancer (SRE) circuit placed in parallel to the main OTA (parallel-type SRE) constitutes a viable solution to reduce the settling time, at the cost of low-power overhead and no modifications of the main OTA. In this work, a practical analytical model has been developed to predict the settling time reduction achievable with OTA/SRE systems and to show the effect of the various design parameters. The model has been applied to a real case, consisting of the combination of a standard folded-cascode OTA with an existing parallel-type SRE solution. Simulations performed on a circuit designed with a commercial 180-nm CMOS technology revealed that the actual settling-time reduction was significantly smaller than predicted by the model. This discrepancy was explained by taking into account the internal delays of the SRE, which is exacerbated when a high output current gain is combined with high power efficiency. To overcome this problem, we propose a simple modification of the original SRE circuit, consisting in the addition of a single capacitor which temporarily boosts the OTA/SRE currents reducing the internal turn-on delay. With the proposed approach a settling-time reduction of 57% has been demonstrated with an SRE that introduces only a 10% power-overhead with respect of the single OTA solution. The robustness of the results have been validated by means of Monte-Carlo simulations.

HIGH-GAIN/EFFICIENCY MULTISTAGE SWITCHED-CAPACITOR-VOLTAGE-MULTIPLIER DC–DC CONVERTER

2012 ◽  
Vol 21 (03) ◽  
pp. 1250023
Author(s):  
YUEN-HAW CHANG
Keyword(s):  
Power Efficiency ◽  
Closed Loop ◽  
Pulse Width Modulation ◽  
High Efficiency ◽  
Conversion Ratio ◽  
Switched Capacitor ◽  
Two Phase ◽  
Analysis And Design ◽  
Voltage Multiplier ◽  
Capacitor Voltage

A closed-loop interleaved multistage switched-capacitor-voltage-multiplier (mc × nc-stage SCVM) dc–dc converter is proposed by combining a variable-conversion-ratio (VCR) and pulse-width-modulation (PWM) control for low-power step-up conversion and high-efficiency regulation. In this SCVM, the power part is composed of two mc-stage SC cells (front) and two nc-stage SC cells (rear) in cascade, and these cells are operated by two-phase nonoverlapping clocks for an interleaved operation with voltage gain of mc × nc at most. This paper presents the VCR control to change the running stage number m,n and topological path for a more flexible and suitable gain level m × n (1 × 1, 2 × 1, 2 × 2, 3 × 1, 3 × 2, 3 × 3,…, mc × nc) according to the desired output so as to improve power efficiency, especially for the lower output. Besides, PWM is adopted not only to enhance output regulation for different outputs, but also to reinforce output robustness to source/loading variation. Further, some theoretical analysis and design include: SCVM model, steady-state analysis, conversion ratio, power efficiency, output ripple, stability, capacitance selection, and control design. Finally, the closed-loop SCVM is simulated, and the hardware is implemented and tested. All the results are illustrated to show the efficacy of the proposed scheme.

HIGH-EFFICIENCY 2-STAGE MULTIPHASE SWITCHED-CAPACITOR CONVERTER VIA VARIABLE-PHASE AND PWM CONTROL

2010 ◽  
Vol 19 (08) ◽  
pp. 1753-1780
Author(s):  
YUEN-HAW CHANG
Keyword(s):  
Power Efficiency ◽  
Closed Loop ◽  
High Efficiency ◽  
Dynamic Error ◽  
Output Regulation ◽  
Switched Capacitor ◽  
Voltage Gain ◽  
Variable Phase ◽  
Analysis And Design ◽  
Switched Capacitor Converter

A closed-loop scheme of 2-stage multiphase switched-capacitor (MPSC) converter is proposed by combining variable-phase control (VPC) and pulse-width-modulation (PWM) technique for low-power DC-DC step-up conversion and high-efficiency output regulation. In this MPSC, there are 2 voltage doublers in series for boosting voltage gain up to 4 at most. Here, VPC is suggested to improve power efficiency, especially for the lower output voltage. It realizes a variable multiphase operation by changing MPSC topological path for more suitable level of voltage gain (4x/3x/2x/1x) according to the desired output. Besides, PWM is adopted for better output regulation not only to compensate dynamic error, but also to reinforce robustness against source/loading variation. Further, the theoretical analysis and design include: MPSC model, steady-state analysis, power efficiency, conversion ratio, ripple percentage, capacitance selection, stability, and control design. Finally, the closed-loop MPSC is simulated, and the hardware implementation is realized and tested. All the results are illustrated to show the efficacy of the proposed scheme.

Design and Analysis of High-Gain Switched-Capacitor-Inductor-Based Inverter for Step-Up DC-AC Conversion

2017 ◽  
Vol 27 (02) ◽  
pp. 1850030 ◽  
Author(s):  
Yuen-Haw Chang ◽  
Yu-Kai Lin
Keyword(s):  
Power Efficiency ◽  
Pulse Width Modulation ◽  
High Gain ◽  
Switched Capacitor ◽  
Analysis And Design ◽  
Stability And Control ◽  
Power Part ◽  
Resonant Inductor ◽  
And Control ◽  
Sinusoidal Pulse Width Modulation

This paper presents the analysis, design and implementation of a closed-loop high-gain switched-capacitor-inductor-based inverter (SCII) by combining a sinusoidal pulse-width-modulation (SPWM) controller and phase generator for realizing the step-up inversion and regulation. The power part is composed of two cascaded sub-circuits from source [Formula: see text] to output voltage [Formula: see text]: (i) SCI booster (one resonant inductor, 4 pumping capacitors and 7 switches regulated by phase generator) and (ii) DC-link inverter (one filter capacitor and 4 switches controlled by SPWM), in order to provide a wide step-up output range of [Formula: see text] as: [Formula: see text] for DC-AC conversion, where [Formula: see text] ([Formula: see text]) is the ratio cycle of charging the inductor (e.g., the maximum of [Formula: see text] reaches 13.8 times voltage of [Formula: see text] while [Formula: see text]). Here, by using the phase generator, the maximum of step-up gain can be regulated for fitting the need of AC load. Further, the SPWM controller is employed to enhance regulation capability for the different amplitude and frequency of output, as well as robustness to loading variation. Some theoretical analysis and design are included: formulation, steady-state analysis, conversion ratio, power efficiency, inductance and capacitance selection, circuit stability and control design. Finally, the performance of SCII is simulated, and verified experimentally on the implemented prototype circuit, and the results are illustrated to show the efficacy of this scheme.

scholarly journals Energy Efficiency in Slew-Rate Enhanced Single-Stage OTAs for Switched-Capacitor Applications

2020 ◽  
Vol 11 (1) ◽  
pp. 1
Author(s):  
Alessandro Catania ◽  
Mattia Cicalini ◽  
Massimo Piotto ◽  
Paolo Bruschi ◽  
Michele Dei
Keyword(s):  
Energy Efficient ◽  
Design Space ◽  
Energy Savings ◽  
Cmos Technology ◽  
System Level ◽  
Switched Capacitor ◽  
Slew Rate ◽  
Rate Enhancement ◽  
Switched Capacitor Circuits ◽  
Parallel Type

Slew-rate enhancement (SRE) techniques assist the charge transfer process in OTA-based switched-capacitor circuits. Parallel-type slew-rate enhancement circuits, i.e., circuits that provide a feed-forward path external to the main OTA, are attractive solutions, since they introduce a further degree of freedom in the speed/power consumption design space without affecting other specifications regarding the main OTA. This technique lends itself to be employed jointly with advanced OTA topologies in order to compose a highly energy efficient OTA/SRE system. However, insights in design choices such as power optimization are still missing for such systems. Here we discuss system level choices with the help of a simple model. Using precise electrical simulations, we demonstrate energy savings greater than 30% for different OTA/SRE systems implemented in a standard 180-nm CMOS technology.

A Simplified Design Model for Modular Steel Buildings Subject to Vapor Cloud Explosions (VCEs)

2020 ◽  
Vol 14 ◽  
Author(s):  
Osama Bedair
Keyword(s):  
Dynamic Response ◽  
Minimum Cost ◽  
Design Parameters ◽  
Front Wall ◽  
Steel Buildings ◽  
Element Analysis ◽  
Analysis And Design ◽  
Vapor Cloud ◽  
Building Components ◽  
Analytical Expressions

Background: Modular steel buildings (MSB) are extensively used in petrochemical plants and refineries. Limited guidelines are available in the industry for analysis and design of (MSB) subject to accidental vapor cloud explosions (VCEs). Objectives: The paper presents simplified engineering model for modular steel buildings (MSB) subject to accidental vapor cloud explosions (VCEs) that are extensively used in petrochemical plants and refineries. Method: A Single degree of freedom (SDOF) dynamic model is utilized to simulate the dynamic response of primary building components. Analytical expressions are then provided to compute the dynamic load factors (DLF) for critical building elements. Recommended foundation systems are also proposed to install the modular building with minimum cost. Results: Numerical results are presented to illustrate the dynamic response of (MSB) subject to blast loading. It is shown that (DLF)=1.6 is attained at (td/t)=0.4 for front wall (W1) with (td/T)=1.25. For side walls (DLF)=1.41 and is attained at (td/t)=0.6. Conclusions: The paper presented simplified tools for analysis and design of (MSB) subject accidental vapor cloud blast explosions (VCEs). The analytical expressions can be utilized by practitioners to compute the (MSB) response and identify the design parameters. They are simple to use compared to Finite Element Analysis.

scholarly journals Design of an Ultra-Wideband Microstrip-to-Slotline Transition on Low-Permittivity Substrate

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1329
Author(s):  
Jung Seok Lee ◽  
Gwan Hui Lee ◽  
Wahab Mohyuddin ◽  
Hyun Chul Choi ◽  
Kang Wook Kim
Keyword(s):  
Microstrip Line ◽  
Return Loss ◽  
Analytical Formula ◽  
Parameter Tuning ◽  
Ultra Wideband ◽  
Design Parameters ◽  
Analytical Line ◽  
Cross Sectional ◽  
Analysis And Design ◽  
Low Permittivity

Analysis and design of an ultra-wideband microstrip-to-slotline transition on a low permittivity substrate is presented. Cross-sectional structures along the proposed transition are analyzed using conformal mapping assuming quasi-TEM modes, attaining one analytical line impedance formula with varying design parameters. Although the slotline is a non-TEM transmission line, the transitional structures are configured to have quasi-TEM modes before forming into the slotline. The line impedance is optimally tapered using the Klopfenstein taper, and the electric field shapes are smoothly transformed from microstrip line to slotline. The analytical formula is accurate within 5% difference, and the final transition configuration can be designed without parameter tuning. The implemented microstrip-to-slotline transition possesses insertion loss of less than 1.5 dB per transition and return loss of more than 10 dB from 4.4 to over 40 GHz.

scholarly journals Variability in Pavement Design

2015 ◽  
Vol 16 (2) ◽  
pp. 50-67 ◽  
Author(s):  
Paola Dalla Valle ◽  
Nick Thom
Keyword(s):  
Pavement Design ◽  
Pavement Performance ◽  
Design Parameters ◽  
Probability Density Distribution ◽  
Analysis And Design ◽  
The Subject ◽  
The Mean ◽  
Subgrade Modulus ◽  
Input Variables ◽  
The Uk

Abstract This paper presents the results of a review on variability of key pavement design input variables (asphalt modulus and thickness, subgrade modulus) and assesses effects on pavement performance (fatigue and deformation life). Variability is described by statistical terms such as mean and standard deviation and by its probability density distribution. The subject of reliability in pavement design has pushed many highway organisations around the world to review their design methodologies, mainly empirical, to move towards mechanistic-empirical analysis and design which provide the tools for the designer to evaluate the effect of variations in materials on pavement performance. This research has reinforced this need for understanding how the variability of design parameters affects the pavement performance. This study has only considered flexible pavements. The sites considered for the analysis, all in the UK (including Northern Ireland), were mainly motorways or major trunk roads. Pavement survey data analysed were for Lane 1, the most heavily trafficked lane. Sections 1km long were considered wherever possible. Statistical characterisation of the variation of layer thickness, asphalt stiffness and subgrade stiffness is addressed. A sensitivity analysis is then carried out to assess which parameter(s) have the greater influence on the pavement life. The research shows that, combining the effect of all the parameters considered, the maximum range of 15th and 85th percentiles (as percentages of the mean) was found to be 64% to 558% for the fatigue life and 94% to 808% for the deformation life.

scholarly journals Efficiency of a Randomized Confirmatory Basket Trial Design Constrained to Control the False Positive Rate by Indication

2020 ◽  
Author(s):  
Linchen He ◽  
Yuru Ren ◽  
Han Chen ◽  
Daphne Guinn ◽  
Deepak Parashar ◽  
...  
Keyword(s):  
False Positive ◽  
Power Efficiency ◽  
Statistical Significance ◽  
False Positive Rate ◽  
Pooled Analysis ◽  
Positive Control ◽  
Design Parameters ◽  
Molecular Oncology ◽  
Basket Trial ◽  
Basket Trials

PURPOSEMolecular oncology determines biomarker-defined niche indications. Basket trials pool histologic indications sharing molecular pathophysiology, potentially improving development efficiency. Currently basket trials have been confirmatory only for exceptional therapies. Our previous randomized basket design may be generally suitable in the resource-intensive confirmatory phase, maintains high power, and provides nearly k-fold increased efficiency for k indications, but controls false positives for the pooled result only. Since false positive control by indications (FWER) may sometimes be required, we now simulate a variant of this basket design controlling FWER at 0.025k, the total FWER of k separate randomized trials.METHODSThe previous design eliminated indications at an interim analysis, conducting a final pooled analysis of remaining indications. To control FWER, we rechecked individual indications at a prospectively defined level of statistical significance after any positive pooled result. We simulated this modified design under numerous scenarios varying design parameters. Only designs controlling FWER and minimizing estimation bias were allowable.RESULTSSequential analyses (interim, pooled, and post-individual tests)) result in cumulative power losses. Optimal performance results when k = 3,4. We report efficiency (expected # true positives/expected sample size) relative to k parallel studies, at 90% power (“uncorrected”) or at the power achieved in the basket trial (“corrected”, because conventional designs could also increase efficiency by sacrificing power). Efficiency and power (percentage active indications identified) improve with higher percentage of initial indications active. Up to 92% uncorrected and 38% corrected efficiency improvement is possible, with power ≈ 60%.CONCLUSIONSEven under FWER control, randomized confirmatory basket trials substantially improve development efficiency. Initial indication selection is critical. The design is particularly attractive when enrollment challenges preclude full powering of individual indications.

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