Physics-of-Failure (PoF) methodology for qualification and lifetime assessment of supercapacitors for industrial applications

Supercapacitors are used nowadays in an extensive range of battery-powered devices such as GPS/GPRS transceivers, active RFID tags, industrial PDAs, electronic locks, micro medical pumps, digital cameras, mobile phones and others. They are also used in vehicle's and machine's sub-systems requiring short but robust powerful current pulses. This covers back-up, delivery and leveling of high peak power as well as storing harvested energy.They are designed to meet high power requirements that cannot be fulfilled by standard batteries. Furthermore, their size and cost are very attractive for industries.However, selecting the right supercapacitor for a specific application remains a real challenge to industry. The specifications of these components only provide limited information about their lifetime for specific stress values. This information is not enough for industries to design a robust product and avoid high field returns.In this paper, we apply the Physics-of-Failure (PoF) methodology for qualification and lifetime assessment of electronic systems, to derive PoF models for supercapacitors at different stresses relevant for some industrial applications. It is expected from these models to better understand the performance of supercapacitors at different stresses and to predict accurate lifetime of supercapacitors allowing industry to robustly design their products and avoid high field returns.     

Physics-of-failure assessment methodology for power electronic systems

Driven by consumer markets and industrial needs, power electronic systems are operating at higher power densities, in smaller packages and in more exotic environments. As these trends continue, ensuring long-term operation in harsher conditions requires accurate reliability prediction models, most viably obtained through Physics-of-Failure (PoF) methodologies. This paper introduces a PoF-based system-level reliability assessment procedure in which the dominant failure mechanisms are identified for three primary subsystems: the power module, DC-link capacitors and the control circuitry. This report outlines the dominant failure modes and mechanisms for each subsystem and provides examples of how to improve subsystem reliability based upon the described assessment methodology. A case study is also presented in which the solder interconnect reliability of the gate-driver board in a mid-range variable frequency drive (VFD) was assessed.     

Efficient and accurate methodology for solving multiserver retrial systems

Proposed is a novel methodology for solving retrial systems which is based on the aggregation of levels of the Markov model beyond a given one. Its evaluation concludes that it is more accurate than previous approximations while requiring a low computational cost.     

A time-domain physics-of-failure model for the lifetime prediction of wire bond interconnects

A new physics-of-failure lifetime prediction model for wire bonds is proposed. It discards the usual cycle-dependent modeling methodology and is instead based on a time domain representation. The bonding interface damage condition is estimated at regular time intervals through a damage model which includes the effect of temperature and time dependent material properties. Thus the impact of time at temperature and other rate sensitive processes on the bond degradation rate can be accurately represented. In addition, the model accounts not only for the damage accumulation processes but also the damage removal phenomena during thermal exposure.     

A life consumption monitoring methodology for electronic systems

Failures in electronic products are often attributable to various combinations, intensities, and durations of environmental loads, such as temperature, humidity, vibration, and radiation. For many of the failure mechanisms in electronic products, there are models that relate environmental loads to the time to failure of the product. Thus, by monitoring the environment of a product over its life cycle, it may be possible to determine the amount of damage induced by various loads and predict when the product might fail. This paper describes the development of a physics-of-failure-based methodology for determining the damage or life consumption in a product. As a demonstration of the methodology, a data recorder has been used to monitor the temperature and vibration loads on a printed circuit board placed under the hood of a car. The data collected by the recorder has been used to determine the life consumption in the solder joints of the printed circuit board due to temperature and vibration loading. The calculated remaining life has then been compared with temperature cycling test results on the board to assess the validity of the approach.     

Similarity approach for reducing qualification tests of electronic components

Qualification analysis and reliability testing of electronic components represent a major activity in the process of development of electronic equipment. Electronics manufacturers have to adopt often costly test programmes to ensure qualification standards and reliability requirements are met. This paper details a novel similarity-based qualification approach for assessing expected reliability of electronic components, and in general electronic products, as an alternative to conventional physical testing. The originality of this work is in the proposed approach which introduces a new way of qualifying electronic components based on similarity with previously assessed and qualified components. This novel approach has the potential to transform in a major way the current operational practices in the industry, demanding at present substantial physical testing, by offering a complementary, “virtual qualification” route for addressing the cost and time challenges associated with qualification tests.A major achievement is the comprehensive and detailed demonstration of the proposed reliability qualification approach. Case studies on qualifying electronic components to the thermal loads induced by a particular post-manufacturing process widely adopted by high-reliability electronics sectors – the robotic hot solder dip (refinishing) process, and associated risks of thermo-mechanical damage are presented and discussed.     

A design-oriented methodology for accurate modeling of on-chip interconnects

An accurate modeling methodology for typical on-chip interconnects used in the design of high frequency digital, analog, and mixed signal systems is presented. The methodology includes the parameter extraction procedure, the equivalent circuit model selection, and mainly the determination of the minimum number of sections required in the equivalent circuit for accurate representing interconnects of certain lengths within specific frequency ranges while considering the frequency-dependent nature of the associated parameters. The modeling procedure is applied to interconnection lines up to 35 GHz obtaining good simulation-experiment correlations. In order to verify the accuracy of the obtained models in the design of integrated circuits (IC), several ring oscillators using interconnection lines with different lengths are designed and fabricated in Austriamicrosystems 0.35 μm CMOS process. The average error between the experimental and simulated operating frequency of the ring oscillators is reduced up to 2% when the interconnections are represented by the equivalent circuit model obtained by applying the proposed methodology.     

Design of telecommunication electronic systems using a hardware/software co-design methodology

Design of real-time electronic systems is critical since these systems include performance constraints as part of their requirements. The goal is to map all functions of such systems on to distributed hardware/software architecture in such a way that all performance constraints can be met. Hardware/software codesign approaches are an important issue. The aim of this paper is to discuss a case study of an X25 system design using a hardware/software co-design methodology. Several alternatives are discussed with respect to their performance. A prototype of the X25 system, which correctly implements the system functionality while meeting real-time requirements, has been experimentally checked.     

Reliability and qualification methodology of 60 W QCW linear bar arrays

The results reported in this publication are related to the qualification of a pilot line at THOMSON-CSF/TCS for the fabrication of 60 W QCW linear bar arrays. This 2-year program supported by the French MoD has been supervised by the Direction de la Recherche et de la Technologie (DRET/TCE) and the Centre d’Electronique de l’Armement (CELAR). The qualification has been conducted in order to fulfil several criteria: demonstration over several batches of the repeatability of performances for linear bar arrays with: COD (Catastrophic Optical Damage)?90 W QCW, efficiency?40% at 60 W, and slope efficiency?1 W/A; storage tests (−40°C, +80°C); ageing tests at 20 and 50°C and reliability assessments. This paper aims to present the methodology used for the qualification and reliability study, and compares it with published results.     

综合电子信息系统体系工程方法研究与应用

为了实现综合电子信息系统的有效集成,提出了多视角的体系工程顶层设计方法、标准规范研究先行的体系工程工作模式设计方法、现代项目管理和共性技术管理以及使用管理相结合的体系工程管理方法、全过程验证的体系工程评估方法等.这些方法和具体措施在工程实践中取得了很好的应用效果,对同类综合电子信息系统的工程研制具有参考意义.     

Modeling and design methodology for mechatronic systems

The integration of mechanical systems and microelectronics opens many new possibilities for process design and automatic functions. After discussing the mutual interrelations between the design of the mechanical system and digital electronic system the different ways of integration within mechatronic systems and the resulting properties are described. The information processing can be organized in multi levels, ranging from low level control through supervision to general process management. In connection with knowledge bases and inference mechanisms, intelligent control systems result. The design of control systems for mechanical systems is described, from modeling, identification to adaptive control for nonlinear systems. This is followed by solving supervision tasks with fault diagnosis. Then design tools for mechatronic systems are considered and examples of applications are given, like adaptive control of electromagnetic and pneumatic actuators, adaptive semiactive shock absorbers for vehicle suspension, and electronic drive-chain damping.     

A methodology for analysis of RTCVD systems

A methodology for predicting the spatial and temporal distribution of film thickness is given for low pressure chemical vapor deposition (LPCVD) in rapid thermal processor (RTP) systems. The methodology is based on a model for the heat transfer to, from, and within the wafer, a geometric ray trace algorithm to predict the radiant heat transfer from the lamps and reflectors to the wafer, a deposition model for the deposited film thickness, and an optical properties model that gives the wafer absorptivity and emissivity. The modeling is for low pressure processes, where gas flow effects are secondary, and concentrates on the radiant heat transfer to and from the wafer. The methodology is based on physical principles, with a minimum reliance on empirical and experimental data, and has been validated by comparison with deposited films from a cylindrical RTP system     

A methodology for the performance evaluation of data querystrategies in universal mobile telecommunication systems (UMTS)

The anticipated emergence of third-generation mobile systems, referred to as universal mobile telecommunication systems (UMTS), raises the problem of reconsidering the design of the databases destined to contain the user information. In particular, it is expected that the key concepts of the new database architectures will be high distribution and fast updating of information. So far, the problem of determining the most appropriate distributed database (DDB) architectures for third-generation mobile systems has not been widely dealt with in literature. This paper presents a methodology for evaluating hierarchical DDB architectures by means of an analytical model of the data querying operation. This methodology allows for structural alternatives, differing on account of the number of levels and branches in the hierarchy, to be evaluated in terms of query loads and mean response times, according to a given user mobility characterization and a given search protocol operation. By way of illustration, the paper discusses a case study, concerning a query operation arising from a location updating procedure and applied to a hierarchical tree-like DDB in which some structural alternatives are considered     

A comprehensive solution for electronic packages' reliability assessment with digital image correlation (DIC) method

The reliability assessment of electronic packages demands more accurate and efficient method for evaluating heterogeneous packages and their interconnects in various measurement conditions. The digital image correlation (DIC) method has been fully developed in the last decade. With proper improvement, this work demonstrates that DIC method has the ability to fulfill various experimental tasks and obtain the information for interconnect strain analysis, coefficient of thermal expansion (CTE) characterization, in-plane displacement and out-of-plane warpage quantification within one measurement. To some extent, it serves as a comprehensive tool for electronic packages' reliability assessment. Given that the DIC technique is new to the electronic packaging area, this work illustrates the principle of optical non-contact experiment method and presents several improvements to fit for the measurement on electronic packaging area. With these applications, it is foreseeable that the DIC method will play an important role in the reliability assessment of electronic packages.     

Building accurate and robust HMM models for practical ASR systems

In this article the relevant training aspects for building robust and accurate HMM models for large vocabulary recognition system are discussed and adjusted, namely: speech features, training steps, and the tying options for context dependent (CD) phonemes. As the basis for building HMM models the well known MASPER training scheme is assumed. First the incorporation of the voicing information and its effect on the classical extraction methods like MFCC and PLP will be shown together with the derivative features, where the relative error reductions are up to 50%. Next the suggested enhancement of the standard training procedure by introducing garbled speech models will be presented and tested on real data. As it will be shown it brings more than a 5% drop in the error rate. Finally, the options for tying states of CD phonemes using decision trees and phoneme classification will be adjusted, tested, and explained.     

Mathematical models and hardware & software for highly accurate electronic temperature meters

Optimal mathematical models accurately describing the dependence of thermometric parameters of sensors within the range of operational temperatures were suggested. Circuit and design concepts, and also algorithms and hardware & software implementing the developed mathematical models in electronic temperature-measuring instruments were developed.     

Closed-form solution for lifetime distribution of single-component failure delay systems

In this note an explicit formula for computing lifetime distribution of single-component failure delay systems is given, along with a program computing it, and comparison is made with an approximate solution.