PCB Trace Thermal Analysis and Effective Conductivity

1992 ◽  
Vol 114 (4) ◽  
pp. 413-419 ◽  
Author(s):  
T. F. Lemczyk ◽  
B. L. Mack ◽  
J. R. Culham ◽  
M. M. Yovanovich
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Heat Source ◽  
Printed Circuit Board ◽  
Effective Conductivity ◽  
Cell Model ◽  
Homogeneous Medium ◽  
Electrical Current ◽  
Circuit Board ◽  
Two Dimensional

The electrical current carrying capability of a surface or buried trace located within a fiberglass printed circuit board (PCB), is of important interest in the microelectronics industry. The maximum allowable trace power, hence local integrity and maximum allowable operating temperature, will depend on several parameters including the circuit board thermal conductivity, thickness, trace size and location. A two-dimensional, steady-state thermal conduction analysis is made on a finite, plane homogeneous medium (PCB), to examine the trace behavior. The trace is modeled as a zero-thickness, strip heat source with specified uniform temperature, and it’s position in the medium is varied. A two-dimensional thermal analysis is also performed on a multilayered cell model with finite heat source, to establish an accurate, effective thermal conductivity for a typical PCB. Results are tabulated and presented graphically for both the two-dimensional trace and effective conductivity models.

Printed Circuit Board Thermal Modeling Without the Use of an Effective Thermal Conductivity

2005 ◽  
Author(s):  
Richard L. Sampson
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Thermal Model ◽  
Printed Circuit Board ◽  
Homogeneous Medium ◽  
Thermal Conductance ◽  
General Purpose ◽  
Circuit Board ◽  
Printed Circuit ◽  
Thermal Analyzer

The complexity of the circuit traces on the layers of a typical printed circuit board (PCB) poses a serious problem when preparing a thermal model of the board. Thermal analysts have resorted to the use of an average or so called, “effective thermal conductivity”, Keff, treating the board as a homogeneous medium in their PCB thermal models. This approach carries with it the possibility of significant error in the prediction of board temperatures. A typical PCB will have large variations in the density and pattern of the circuit traces, and a single value of Keff cannot accurately represent all board locations. An alternative approach to this long standing problem is presented in this paper. In the new procedure the thermal conductance between pairs of nodes is computed using all of the details of the circuit traces in the internodal region. The trace information is obtained from bitmap files of each circuit layer, files which may be generated from the board CAD files. The conductances are utilized in a general purpose thermal analyzer for computation of system temperatures. Using the details of the local circuit traces in the computation of internodal conductances results in a more accurate thermal model.

Two-Dimensional Optical Interconnection Based on Two-Layered Optical Printed Circuit Board

2007 ◽  
Vol 19 (6) ◽  
pp. 411-413 ◽  
Author(s):  
Sung Hwan Hwang ◽  
Mu Hee Cho ◽  
Sae-Kyoung Kang ◽  
Tae-Woo Lee ◽  
Hyo-Hoon Park ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Optical Interconnection ◽  
Two Dimensional ◽  
Printed Circuit

The restoration of temperature distribution in a two-dimensional domain by a tomographic method by using the results of measurements for electric resistance of oriented conductors

2018 ◽  
Author(s):  
В.А. Деревянко ◽  
А.Ф. Латыпов
Keyword(s):  
Mathematical Model ◽  
Temperature Distribution ◽  
Real Time ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Two Dimensional ◽  
Electronic Unit ◽  
Resistance Thermometer ◽  
Printed Circuit ◽  
Radio Electronic

Рассмотрена возможность использования “термометра сопротивления” для измерения распределения температуры в двумерной области. Создана математическая модель датчика, сводящаяся к решению томографической задачи. Важной особенностью модели является то, что число уравнений в системе линейных алгебраических уравнений (СЛАУ) больше числа переменных. Это позволяет уменьшить ошибки в исходных данных. Создана программа для определения решения СЛАУ с плохо обусловленной матрицей, позволяющая обрабатывать результаты измерений в реальном масштабе времени. Выполнен тестовый расчет. При малом числе ракурсов измерений получена удовлетворительная точность восстановления температуры. Purpose. To ensure a long period of active lifetime of space vehicles, it is necessary to use effective methods and means to control physical processes leading to premature failure of on-board radio electronic equipment both at the stage of ground testing and during active operation of the spacecraft in space. Long-term testing experience for electronic equipment shows that monitoring compliance with necessary temperature conditions of onboard equipment plays the main role in ensuring reliability. Ideally, the thermal control should be performed for all elements of radio electronic units in real time. Method. The possibility of using a “two-dimensional resistance thermometer” for recording the thermal field of a printed circuit board of an electronic unit is considered. The principle of operation of the thermometer is based on the measurement of integral resistances of extended mutually intersecting conductors in a medium with inhomogeneous temperature distribution. The registration of the integral resistances of individual conductors is possible with the help of an automated measuring system by solving the tomographic problem aimed to obtain the temperature distribution on the surface of the printed circuit board. Result. The design of the “two-dimensional temperature sensor” is considered. The sensor is technologically compatible with the design of the printed circuit board of the radio electronic unit. A mathematical model of the sensor is developed. It is reduced to the solution of a tomographic problem. A program for solving a system of linear equations with an ill-conditioned matrix is developed that provides the real-time processing for measurement results. The test calculation is performed. A satisfactory accuracy of the temperature restoration is achieved. Conclusion. A “two-dimensional resistance thermometer” can be used to measure a two-dimensional temperature field for a printed circuit board of a radio electronic unit in real time. The mathematical model allows adapting the thermometer design to a specific radio electronic unit and selecting the required accuracy of the temperature field restoration.

Evaluation of Effective Thermal Conductivity of Multilayer Printed Circuit Board

2011 ◽  
Author(s):  
Toshio Tomimura ◽  
Yoshihiro Shiotsu ◽  
Yasushi Koito ◽  
Masaru Ishizuka ◽  
Tomoyuki Hatakeyama
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Printed Circuit Board ◽  
Evaluation Method ◽  
Circuit Board ◽  
Printed Circuit ◽  
Plane Direction ◽  
Simple Evaluation

To perform a rational thermal design of a printed circuit board (PCB) with highly anisotropic heat transfer nature in its initial stage, effective thermal conductivities in thickness direction and in in-plane direction must be given depending on the electric circuit of the board. However, a simple evaluation method for the effective thermal conductivities of such PCB has not been developed yet. In this study, as the first step to propose a simple evaluation method, the heat transfer coefficient by natural convection around a horizontal disk, which is indispensable for measuring the effective thermal conductivity, has been evaluated. Furthermore, the thermal conductivity of the glass epoxy resin in in-plane direction has been evaluated by applying the evaluated heat transfer coefficient, and then, the validity of the proposed thermal conductivity measurements of the anisotropic PCB has been confirmed.

Study on High Thermal Conductive BN/Epoxy Resin Composites

2011 ◽  
Vol 105-107 ◽  
pp. 1751-1754 ◽  
Author(s):  
Hui Wang ◽  
Peng Chen ◽  
Jian Sun ◽  
Xiao Jun Kuang ◽  
Zhen Kun Yao
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Heat Dissipation ◽  
Printed Circuit Board ◽  
Filler Particle ◽  
Linear Increase ◽  
Circuit Board ◽  
Composite Matrix ◽  
Sem Image ◽  
Filler Particle Size

In contemporary electronic technology era, the volume of electronic equipment and printed circuit board reduced so dramatically that the requirements of heat dissipation and insulation increase thereafter. In this research, γ-aminopropyltriethoxysilane (KH550)-treated boron nitride (BN) powder was used as a filler to modify epoxy composites. Effects of the BN particle size and concentration on the thermal conductivity of composites were investigated. SEM image showed the treated BN filler dispersed well in the composite matrix. Moreover, the thermal conductivity was enhanced as the BN concentration was increased. Similar phenomenon was also observed when the filler particle size was reduced. Results indicated that with increasing amount of BN addition, the composites’ thermal conductivity showed a nearly linear increase. When the mass fraction of BN was 30% and its particle size was 220 nm, the thermal conductivity reached 3.4 W/(m•k), which was 17 times as high as that of pure EP resin.

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