Design Of Electronic Equipment Research Articles

A CFD Study on the Effect of Shrinking Box Size on Cooling Airflows in Compact Electronic Equipment—The Case of Portable Projection Display Equipment

This work is concerned with the thermal design of portable projection display equipment (i.e., a portable projector). The portable projector is being made smaller and lighter to better serve the carrier, while its luminance is enhanced to benefit the viewer. The confluence of these demands increases the thermal loading on the projector. The design of cooling airflow path is becoming evermore important; however, the complex internal organization of the projector hampers an attempt to conduct flow and heat transfer analysis. A particularly important issue for the projector designer is to predict the effect of shrinking box size of the next generation product on cooling airflow. This paper describes a way to foresee the effects of reducing the key geometric dimensions of the projector on the distribution of airflow. The analysis is conducted using a computational fluid dynamics (CFD) code. CFD results are obtained on sampled points in the parameter domain and used to find the effects of various geometric parameters on the airflow rates. The sampling and screening of CFD results follows the Taguchi method (or the method of experimental design). The most influential parameters for the total airflow rate and the airflow rate over the electronics board are identified. This conclusion, however, is only an illustration of how the CFD analysis can assist the equipment designer in planning the next generation product. The methodology reported here can be applied in the plan and design of other electronic equipment that have similarly complex internal organizations in shrinking system boxes.

Automated control of the velocity of in-tube diagnostic tools for main gas pipelines: II. Electronic equipment of a bypass device

The design and operation of electronic in-tube nondestructive-testing equipment containing a bypass device are described. The electronic equipment designed for the bypass device is built in the general system of onboard electronic equipment and performs automatic control of the preset velocity of a flaw detector or other diagnostic pigs moving through a pipeline.

Best before...[electronic equipment reliability

This paper deals with the reliability in the design of electronic equipment. Eighteen months after a chip is made is not probably the same piece of silicon five years later. It means the longevity of chip is becoming an issue. The electronics industry is beginning its shift from manufacturing processes with minimum dimensions of 65 nm to those with minimum dimensions of 45 nm.

Information quality factors affecting innovation process

This research aims to identify the information quality (IQ) dimensions and measures affecting the innovation management process. The research employs case study methodology and uses an information quality technique knows as Information Function Deployment (IFD). The selected case is an organisation dealing with the design and manufacture of electronic equipment and tools used for medical testing. This research identifies four IQ dimensions and six IQ measures affecting the innovation management process. The identified IQ dimensions are timeliness, interpretability, coherency and completeness while the IQ measures are information sensing, information collecting, information processing, information organising, information integrity and information sharing.

Three-proofing design of shipborne electronic equipment

The design of moisture-mildew-saltspray proofing to shipborne electronic equipment is an important mission for the shipborne electronic equipment operating at the ocean envi-ronment.It should be considered overall from the materi-als-application,structure design,process engineering and so on at the time of the product development.The accurate use of metal material with good corrosion resistance and the nonmetal material with good mildew-proofing and aging resistance is the basis of the design.Most corrosion could be avoided by the rational structural design.The rationality of the structural de-sign would affect mostly the adaptive capacity to environment of the product and is the key factor for the mois-ture-mildew-saltspray proofing design of the shipborne elec-tronic equipment.It would improve the proofing capability farther that the correct use of the material modification,surface coating/depositing,impregnation,encapsulation,insulation process and so on.At present,the coating-film technology would only solve the moisture-mildew-saltspray proofing prob-lem in the circuit component under the L-band,but the encap-sulation of application environment of micro/millimeter wave circuit component and the electromagnetic shielding composite technology could prevent effectively the ubiquitous galvanic corrosion,ensure that the component could adapt the inclement environment,and the shielding properties should be above 80 dB during the 0.1~10 GHz operating frequency,and meet the waterproof requirement of the three meter depth impregna-tion.Hermetic package is used at the millimeter-wave T/R components in which the bare chips are micropackaged for the moisture-mildew-saltspray proofing.The helium mass spectrum leakage detection rate should be less than 1×10-8 Pa·m3/s of the GJB requirement,which could ensure the reliability of the circuit component.

B232 電子機器冷却設計のための空冷ファンモデル(エレクトロニクス機器・デバイスのサーマルマネージメント2)

B232 電子機器冷却設計のための空冷ファンモデル(エレクトロニクス機器・デバイスのサーマルマネージメント2)

508 電子機器冷却設計のための空冷ファンモデル(熱工学(2))

508 電子機器冷却設計のための空冷ファンモデル(熱工学(2))

Life margin assessment with Physics of Failure Tools application to BGA packages

Designers of electronic equipment are faced with the contractual obligation of guaranteeing that their products will fulfil the specifications on life duration. Classically, empirical methods based on databases and handbooks are used and features such as Mean Time Between Failure (MTBF) are provided. This paper presents how to use Physics of Failure (PoF) tools and results in order to provide the customer with a reliability feature, called life margin, based on Cycles To Failure (CTF) figures. The method defines and computes a life margin for 99% of the population in the given environmental life conditions. This feature is used to evaluate the different technological possibilities and decide the best trade-off to satisfy the customer’s requirement on life duration. The method has been applied to a given board and a given application, where the component, which limits reliability, has been identified as being packaged in a Ball Grid Array (BGA) package.

1308 応答曲面法による電力同定手法を適用した上流熱設計 : 汎用インバータ機器への適用(CO2 設計コンテストI)

Thermal design of electronic equipment in early design stage is the most effective way for reducing the material cost, product size and total developing time. To realize the frontloading thermal design, accurate estimation method of device power dissipation must be required. However, there is no way to measure the power dissipation of inverter due to the variation of device properties, test conditions and so on. We apply an identification method using response surface methodology (RSM) with CFD to estimate the power dissipation of multiple devices on printed wired board. As a verification result, identification error in total power is just 3.4%. This practical approach improves the accuracy of early thermal design quality dramatically.

A New Role of CFD Simulation in Thermal Design of Compact Electronic Equipment: Application of the Build-up Approach to Thermal Analysis of a Benchmark Model

Computational Fluid Dynamics (CFD) codes have proved their high potential as a tool of thermal design of electronic equipment. However, as the product development cycle is shortened, the CFD-based thermal design needs a new format that allows the packaging designer fast and versatile searches for better design options. The most serious factor that slows the CFD-based design is geometric complexity created by packing various components in a tight space of the system box. In a proposed methodology coined “Build-up Approach (BUA),” CFD simulations are conducted on a set of hardware models to gain insight into the effects of component placement on the junction temperature. Two algorithms are introduced before and after CFD simulations: one defines the geometric parameters through singular value decomposition (SVD) of components placement patterns and the other identifies important geometric parameters by means of the Taguchi method. A case study was conducted on a simple hardware model (benchmark model) that embodies essential features of portable electronic equipment. The results proved the effectiveness of these algorithms in measuring the relative importance of geometric parameters and weeding out unimportant geometric details.

Chimney Effect on Natural Air Cooling of Electronic Equipment Under Inclination

With the rapid increase of the power dissipation density in modern electronic equipment, the cooling design of electronic equipment becomes increasingly important. For widely used forced-convection air-cooled systems, the reliability of and the acoustic noise of the fan present serious concerns as the air velocity is increased to enhance the cooling capacity. Thus, the interest in natural-convection air cooling is growing to take advantage of low noise and energy savings inherent in that cooling mode. One method of promoting the capacity of natural air cooling is to incline the electronics casing, thereby, induce draft air by what is called the chimney effect. However, the effect of inclination on thermal behavior and cooling capacity has not yet been fully understood due to the involvement of many parameters in driving the draft air. This paper presents the results of experimental and numerical studies on the effect of casing inclination on the temperature rise across the casing. The numerical simulation was implemented to find out the thermal behavior inside a thin electronic casing. The simulation results are in good agreement with the experiment data. A thermal design guide is obtained regarding how the cooling effect is improved by increasing the inclination angle.

Development of thermal flow simulation method for switch mode power supplies and its integration with electric circuit analysis (in the case of natural convection air cooled switch mode power supply)

AbstractThis paper describes the development of a thermal flow simulation method for the design of electronic equipment. In the proposed sequence of analyses, the electric circuit analysis for estimating power loss in power semiconductor devices was integrated with the thermal analysis. The method was applied to the thermal design of a new switch mode power supply (SMPS). The analysis was carried out using a commercially available computational fluid dynamics (CFD) code. In reducing actual structural organizations of the printed circuit board (PCB) and the power semiconductor devices to simpler models, the method of experimental design (MED) was employed. Following the prescription of MED, the PCB was treated as a simple plate having the same thermal conductivity as epoxy resin, and the power semiconductor devices were modeled by hexahedral resistance network. The heat sources were a field effect transistor (FET) and a diode. Computation of power loss from the FET and the diodes is described and the accuracy of different estimation methods is discussed. The difference between measured and calculated temperature rises of the power semiconductor devices was found to be within approximately 10 K. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(8): 473–489, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20037

Numerical and experimental study of the effect of inclination on the thermal behaviour of natural convection inside a thin electronic equipment casing

With rapid increase in the power dissipation density in modern electronic equipment, the cooling design of electronic equipment becomes increasingly important. For widely used forced-convection air-cooled systems, the reliability and acoustic noise of the fan present serious concerns as the air velocity is increased to enhance the cooling capacity. Thus, the interest in natural-convection air cooling is growing to take advantages of the low noise and energy saving inherent in that cooling mode. One method of promoting the capacity of natural air cooling is to incline the electronics casing and thereby induce draft air by what is called the chimney effect. However, the effect of inclination on the thermal behaviour and the cooling capacity has not yet been fully understood owing to the involvement of many parameters in driving the draft air. This paper presents the results of experimental and numerical studies on the effect of casing inclination on the temperature rise across the casing. Numerical simulation was carried out to find the thermal behaviour inside a thin electronic equipment casing. The simulation results are in good agreement with experimental data. A thermal design guide is obtained regarding how the cooling effect is improved by increasing the inclination angle.

C155 コンパクト PC 用空冷ファンの性能評価

In a thermal design of compact electronic equipment, the estimation of cooling air flow rate is essential. This paper deals with an experimental study for performance evaluation of cooling fans, in case when obstacles modeling a high-density packing condition are placed around a fan or the inlet of a package is partially closed, aiming to shed a light on the relationship between flow rate and flow condition near intake region of a cooling fan. It is shown that the pressure difference between the front and rear of a fan should be evaluated carefully, when the shape of a flow passage changes abruptly in front of a cooling fan.

Low stray inductance bus bar design and construction for good EMC performance in power electronic circuits

Ten years after the publication of the EC Directive 89/336 on electromagnetic compatibility, the impact of this directive on design and lay-out of modern electrical and electronic equipment can be observed. Many research and development studies have proposed and evaluated detailed improvements in the area of component design, component selection, circuit lay-out, shielding and active and passive filtering. New and innovative solutions to minimize noise, especially common mode conducted electromagnetic interference (EMI), in power electronic circuits continue to be developed. In this paper, the authors investigate to what extent EMI caused by power electronic devices in hard switching inverter topologies can be minimized using ultra-low inductive planar busbars. The concept followed in this study is to tackle EMI directly at the source where most EMI is generated; in other words, to reduce the parasitic magnetic energy stored in the inverter DC link to reduce high voltage spikes during switching. A planar busbar was built, tested and analyzed. Measurements show the validity of the theoretical, but simple, design procedure for planar busbars in power converters.

646 電子機器熱設計のためのビルドアップアプローチ : 複雑幾何形状への対応法

A JSME project is in progress to implement a methodology called the Build-up Approach (BUA). The BUA is designed to expedite thermal design of electronic equipment. Following the description of BUA concept presented earlier at the 02 JSME Annual Meeting, this presentation focuses on one of the key steps involved in the knowledge development phase. Components placement in the system box is represented by two groups of numeral strings. The string groups correspond to the modes of components shuffling on the printed card board or in the system box, tile shuffling and vector shuffling. Strings manipulation enables organised search for a components placement pattern that renders higher thermal performance.

A Case Study: Application of Parametric Cost Analysis to Claims Related to Scope Changes

Abstract During proposal preparation, many organizations use parametric tools to develop cost estimates and compare alternative approaches. A less common application of parametric analysis involves identification of costs for alleged out-of-scope or unplanned work in support of damage claims and legal proceedings. This paper presents a case study of a parametric cost estimating system that was used in a legal filing to substantiate out-of-scope engineering costs related to the design of electronic test equipment. Due to a failure in project management methods, the firm had minimal data to substantiate cost claims related to alleged scope changes. As a result it developed a number of parametric estimation methods to support the claim. Unfortunately, these approaches developed dependent, correlated cost terms that increased the variance and uncertainty of the resulting estimate. The paper demonstrates the importance of using a project work breakdown structure that is traceable throughout the project executi...

E207 電子機器の熱設計に関するビルドアップアプローチ : 機械学会RCプロジェクト(オーガナイズドセッション21 : 電子機器の熱設計と解析の応用)

In order to expedite thermal design of electronic equipment a hierarchical organisation of the design work is proposed. In the knowledge development level, the computational fluid dynamics (CFD) simulation is performed on a set of template designs in the product development phase. From the solution body a fast-to-use design code will be developed for use in the actual design phase. This paper describes the basic concept, and illustrates the methods of knowledge extraction on some examples.

Application of a semi-empirical approach to the thermal design of electronic equipment

A semi-empirical approach to the thermal design of electronic equipment is presented. Although recent progress in computer technology has enabled a complex analysis to be made, it is difficult to carry out numerical studies for practical electronic equipment cabinets, which have extremely complicated boundary conditions due to the various sized components mounted in the cabinets. It has thus become important to establish an analytical model in order to apply computer simulation to the thermal design of electronic equipment. This paper reports the semi-empirical approach based on a lumped model, and experimental data on the flow resistance coefficient and heat transfer coefficient. A simulation was carried out for a photocopy machine model by using a personal computer. The proposed method is confirmed to be capable of serving thermal designers satisfactorily.

Deciphering the deluge of data

Electronic equipment designers use the part manufacturers' data sheets to help select parts. To do so efficiently and effectively, designers must understand the data sheet and the constraints part manufacturers place on the use of their parts. Although equipment designers are not necessarily bound by those constraints, they must be aware of them in order to avoid misinterpretation. This article provides a primer on the contents of an electronic data sheet, focusing on the environmental and operational constraints as well as electrical parameters in the context of their relationship with specification limits. The purpose is to make the reader aware of the issues that must be considered in using electronic part data sheets.