Forced Convection Board Level Thermal Design Methodology for Electronic Systems

2000 ◽  
Vol 123 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Reena Cole ◽  
Tara Dalton ◽  
Jeff Punch ◽  
Mark R. Davies ◽  
Ronan Grimes
Keyword(s):  
Design Methodology ◽  
Influence Factors ◽  
Reynolds Numbers ◽  
Thermal Design ◽  
Junction Temperature ◽  
Electronic Systems ◽  
Design Rules ◽  
Passive Components ◽  
Continued Use ◽  
Board Level

The case is made for the continued use of single valued thermal resistances for the prediction of component junction temperature, and, hence, reliability. These values are adjusted using empirically determined influence factors to account for thermal and aerodynamic interactions at board level. The paper presents measured values of influence factors for arrays of Plastic Quad Flat Packs (PQFPs) over a range of Reynolds numbers and with a series of board level obstacles modeling upstream passive components. The results are formulated into a novel set of design rules.

A Board Level Study of an Array of Ball Grid Components—Aerodynamic and Thermal Measurements

2003 ◽  
Vol 125 (4) ◽  
pp. 480-489 ◽  
Author(s):  
Reena Cole ◽  
Mark Davies ◽  
Jeff Punch
Keyword(s):  
Printed Circuit Board ◽  
Influence Factors ◽  
Thermal Characteristics ◽  
Electronic System ◽  
Circuit Board ◽  
Junction Temperature ◽  
Design Rule ◽  
Flat Plates ◽  
Thermal Measurements ◽  
Board Level

Electronic package manufacturers publish thermal characteristics of components, which are measured using standard tests, measuring a thermal resistance value for a single component on a standard test printed circuit board (PCB). This limits the applicability of the characterization, as it does not show what aerodynamic or thermal interaction each package will have in a real system. This paper presents a new board-level electronics system test vehicle consisting of an array of ball grid components on three different effective thermal conductivity multi-layer PCB’s. Aerodynamic and thermal measurements are presented. It appears that PCB’s populated with low profile electronic packages behave like flat plates, leading to the proposition that component temperatures can be calculated using flat plate predictions. It is shown how both the airflow and the board conductivity can have a critical effect on the junction temperature, and a simple design rule is suggested, in terms of influence factors, to take account of these effects. These will lead to better estimates of electronic system reliability in the early part of the design cycle.

scholarly journals Experimental and numerical investigation of heat dissipation from an electronic component in a closed enclosure

2018 ◽  
Vol 144 ◽  
pp. 04010
Author(s):  
Bobin Saji George ◽  
M. Ajmal ◽  
S. R. Deepu ◽  
M. Aswin ◽  
D. Ribin ◽  
...  
Keyword(s):  
Power Dissipation ◽  
Heat Dissipation ◽  
Numerical Study ◽  
Electronic Component ◽  
Thermal Design ◽  
Electronic Systems ◽  
Computational Domain ◽  
Computational Tool ◽  
Cycle Times ◽  
Design Cycle

Intensifying electronic component power dissipation levels, shortening product design cycle times, and greater than before requirement for more compact and reliable electronic systems with greater functionality, has heightened the need for thermal design tools that enable accurate solutions to be generated and quickly assessed. The present numerical study aims at developing a computational tool in OpenFOAM that can predict the heat dissipation rate and temperature profile of any electronic component in operation. A suitable computational domain with defined aspect ratio is chosen. For analyzing, “buoyant Boussinesq Simple Foam“ solver available with OpenFOAM is used. It was modified for adapting to the investigation with specified initial and boundary conditions. The experimental setup was made with the dimensions taken up for numerical study. Thermocouples were calibrated and placed in specified locations. For different heat input, the temperatures are noted down at steady state and compared with results from the numerical study.

Numerical Thermal Simulation of Cryogenic Power Modules Under Liquid Nitrogen Cooling

2005 ◽  
Vol 128 (3) ◽  
pp. 267-272 ◽  
Author(s):  
Hua Ye ◽  
Harry Efstathiadis ◽  
Pradeep Haldar
Keyword(s):  
Liquid Nitrogen ◽  
Electrical Current ◽  
Oxide Semiconductor ◽  
Junction Temperature ◽  
Electronic Systems ◽  
Power Module ◽  
Power Modules ◽  
Allowable Range ◽  
Liquid Nitrogen Cooling ◽  
Thermal Simulations

Understanding the thermal performance of power modules under liquid nitrogen cooling is important for the design of cryogenic power electronic systems. When the power device is conducting electrical current, heat is generated due to Joule heating. The heat needs to be efficiently dissipated to the ambient in order to keep the temperature of the device within the allowable range; on the other hand, it would be advantageous to boost the current levels in the power devices to the highest possible level. Projecting the junction temperature of the power module during cryogenic operation is a crucial step in designing the system. In this paper, we present the thermal simulations of two different types of power metal-oxide semiconductor field effect transistor modules used to build a cryogenic inverter under liquid nitrogen pool cooling and discussed their implications on the design of the system.

Thermal Design of a Satellite Borne FPGA

2011 ◽  
Vol 52-54 ◽  
pp. 1411-1414 ◽  
Author(s):  
Bo Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Heat Sink ◽  
Thermal Design ◽  
Junction Temperature ◽  
Element Analysis

Thermal design and analysis of a satellite borne FPGA is described in this paper. Thermal-conductive glue, vias and an aluminum bar were used to the FPGA and the PCB under the FPGA in order to help conduct the heat of the FPGA to heat sink. The results of finite element analysis showed that the case temperature of the FPGA decreased from 132.5°C to 55.4°C and the junction temperature decreased from 136.1°C to59.0 °C after the thermal design, which matches the requirements of thermal design.

Approximate Analytical Model for a First Level Package With Non-Uniformly Powered Die

2006 ◽  
Author(s):  
Abhijit Kaisare ◽  
Dereje Agonafer ◽  
A. Haji-Sheikh ◽  
Greg Chrysler ◽  
Ravi Mahajan
Keyword(s):  
Thermal Resistance ◽  
Analytical Model ◽  
Functional Integration ◽  
Thermal Design ◽  
Junction Temperature ◽  
Direct Result ◽  
Design Guideline ◽  
Functional Blocks ◽  
Distribution Of Power ◽  
Functional Components

Microprocessors continue to grow in capabilities, complexity and performance. Microprocessors typically integrate functional components such as logic and level two (L2) cache memory in their architecture. This functional integration of logic and memory results in improved performance of the microprocessor as the clock speed increases and the instruction execution time has decreased. However, the integration also introduces a layer of complexity to the thermal design and management of microprocessors. As a direct result of function integration, the power map on a microprocessor is typically highly non-uniform and the assumption of a uniform heat flux across the chip surface is not valid. The active side of the die is divided into several functional blocks with distinct power assigned to each functional block. Previous work [1,2] has been done to minimize the thermal resistance of the package by optimizing the distribution of the non-uniform powered functional blocks with different power matrices. This study further gives design guideline and key pointers to minimized thermal resistance for any number of functional blocks for a given non-uniformly powered microprocessor. In this paper, initially (Part I) temperature distribution of a typical package consisting of a uniformly powered die, heat spreader, TIM 1 & 2 and the base of the heat sink is calculated using an approximate analytical model. The results are then compared with a detailed numerical model and the agreement is within 5%. This study follows (Part II) with a thermal investigation of non-uniform powered functional blocks with a different power matrices with focus on distribution of power over die surface with an application of maximum, minimum and average uniform junction temperature over a given die area. This will help to predict the trend of the calculated distribution of power that will lead to the least thermal gradient over a given die area. This trend will further help to come up with design correlations for minimizing thermal resistance for any number of functional blocks for a given non-uniformly powered microprocessor numerically as well as analytically. The commercial finite element code ANSYS® is used for this analysis as a numerical tool.

Development of Statistical Core Thermal Design Methodology Using a Modified Latin Hypercube Sampling Method

1991 ◽  
Vol 94 (3) ◽  
pp. 407-415 ◽  
Author(s):  
Seung-Hyuk Lee ◽  
Hyun-Koon Kim ◽  
Sang-Ryeol Park ◽  
Soon-Heung Chang
Keyword(s):  
Design Methodology ◽  
Sampling Method ◽  
Latin Hypercube Sampling ◽  
Thermal Design ◽  
Latin Hypercube

Reliability of Novel Ceramic Encapsulation Materials for Electronic Packaging

2018 ◽  
Vol 2018 (1) ◽  
pp. 000425-000433
Author(s):  
S. Kaessner ◽  
M.G. Scheibel ◽  
S. Behrendt ◽  
B. Boettge ◽  
K.G. Nickel
Keyword(s):  
Wide Bandgap ◽  
Electronic Systems ◽  
Chip Surface ◽  
Passive Components ◽  
Chip Area ◽  
Research Activities ◽  
Major Interest ◽  
Recent Developments ◽  
Polymeric Encapsulation ◽  
Thermal Conductivities

Abstract Enhancements on power electronic systems with reduced chip area and miniaturized passive components are subject of several research activities in academics and industry. To realize such future electronic devices, it is necessary to incorporate wide bandgap semiconductor technology such as silicon carbide and gallium nitride operating at higher temperatures. Therefore, the development of novel materials with high thermal conductivities and stability, withstanding harsh environments up to 300°C is of major interest. Especially, polymeric encapsulation materials have to be improved because of common degradation effects above 175°C. Ceramic (nonpolymeric) materials with thermal conductivities above 5 W/(m·K) already illustrated promising results for the encapsulation of power electronics. The present work illustrates recent developments and improvements on novel ceramic encapsulation materials, which finally avoid critical interactions with the chip surface. Furthermore, advances in reliability will be discussed in terms of passed high-temperature reverse bias and humidity tests correlated with relevant material properties.

An Investigation Into the Potential of Low-Reynolds Number Eddy Viscosity Turbulent Flow Models to Predict Electronic Component Operational Temperature

2005 ◽  
Vol 127 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Peter Rodgers ◽  
Vale´rie Eveloy ◽  
M. S. J. Hashmi
Keyword(s):  
Thermal Analysis ◽  
Reynolds Number ◽  
Eddy Viscosity ◽  
Predictive Accuracy ◽  
Low Reynolds Number ◽  
Turbulence Models ◽  
Thermal Design ◽  
Junction Temperature ◽  
Temperature Prediction ◽  
Low Reynolds

The flow modeling approaches employed in computational fluid dynamics (CFD) codes dedicated to the thermal analysis of electronic equipment are generally not specific for the analysis of forced airflows over populated electronic boards. This limitation has been previously highlighted (Eveloy, V. et al., 2004, IEEE Trans. Compon., Packag., Technol. 27, pp. 268–282), with component junction temperature prediction errors of up to 35% reported. This study evaluates the potential of three candidate low-Reynolds number eddy viscosity turbulence models to improve predictive accuracy. An array of fifteen board-mounted PQFPs is analyzed in a 4 m/s airflow. Using the shear stress transport k-ω model, significant improvements in component junction temperature prediction accuracy are obtained relative to the standard high-Reynolds number k-ε model, which are attributed to better prediction of both board leading edge heat transfer and component thermal interaction. Such improvements would enable parametric analysis of product thermal performance to be undertaken with greater confidence in the thermal design process, and the generation of more accurate temperature boundary conditions for use in Physics-of-Failure based reliability prediction methods. The case is made for vendors of CFD codes dedicated to the thermal analysis of electronics to consider the adoption of eddy viscosity turbulence models more suited to board-level analysis.

Rage against the machine: moral anger in whistleblowing

2019 ◽  
Vol 14 (3) ◽  
pp. 337-355 ◽  
Author(s):  
Chris Mason ◽  
John Simmons
Keyword(s):  
Decision Making ◽  
Qualitative Study ◽  
Design Methodology ◽  
Anger Expression ◽  
Theoretical Framework ◽  
Content Type ◽  
Extant Literature ◽  
Moral Anger ◽  
Board Level ◽  
Corporate Wrongdoing

Purpose The purpose of this paper is to offer a theoretical framework of whistleblowing that gives due recognition to the emotional and reflexive processes that underpin it. Modes of anger are integrated into the model based on a reading of Geddes and Callister (2007), and developed by Lindebaum and Geddes (2016) work on moral anger. Design/methodology/approach The model is derived by interrogation of the extant literature on whistleblowing with due recognition accorded to emotional and reflexive dimensions that have been underrepresented in previous research. The model was tested by a qualitative study that uses memoir analysis to interrogate a board level whistle-blower’s account of the complex, traumatic and like-changing nature of his experience. Findings The paper identifies key stages in whistle-blower thinking before, during and subsequent to a decision to expose corporate wrongdoing. It demonstrates how emotional and reflexive processes influence a whistle-blower’s mode of anger expression, and how different perspectives by the whistle-blower and the focal organisation may view this expression as moral or deviant anger. Research limitations/implications The complexity of the whistleblowing process, together with possible alternative perspectives of it, makes identifying every influencing variable extremely challenging. Also, reliance on a whistle-blower’s own account of his experience means that recall may be partial or self-serving. The model can be used to analyse other whistle-blower accounts of their experience, and further confirm its applicability. Originality/value This is the first application of memoir analysis to a whistle-blower’s account of his experience that relates modes of anger expression to stages in the whistleblowing episode. It addresses a significant imbalance in whistleblowing research that hitherto has emphasised rationality in whistle-blower decision making and downplayed the influence of reflexivity and emotion.

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