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.

Thermal Model of Printed Circuit Board Plated-Through Hole under One-Sided Heating Conditions

2021 ◽  
Vol 26 (5) ◽  
pp. 426-431
Author(s):  
V.A. Sergeev ◽  
◽  
A.M. Khodakov ◽  
M.Yu. Salnikov ◽  
◽  
...  
Keyword(s):  
Quality Control ◽  
Thermal Resistance ◽  
Thermal Model ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Thermal Models ◽  
Printed Circuit ◽  
Plated Through Hole ◽  
Through Hole

Thermal methods of quality control of the plated-through hole (PTH) of printed circuit board (PCB) are based on thermal models. However, known thermal models of PTH take no account of heat transfer to PCB material thus not allowing for PTH heat characteristic tying up with adhesion quality. In this work, an axisymmetric thermal model of a single-layer PCB PTH under one-sided heating conditions is considered. It was shown that the ratio of the temperature increments of the upper (heated) and lower end of the PTH in the considered range of heating power does not depend on the power level. A linear thermal equivalent scheme of the PTH has been proposed, which includes the longitudinal thermal resistance of the PTH metallization, de-termined by the parameters and quality of the metallization layer, the thermal resistance, which determines the convection heat exchange between the ends of the PTH with the adjacent PCB surface and the environment, and the thermal resistance of the area of the PCB material adjacent to the PTH, depending on the quality of the metallization adhesion and the PCB dielectric. Thermal equivalent circuit parameters determined by the ratio of the temperature increment of the upper and lower ends of the PTH and their difference can serve as the basis for the development of a nondestructive inspection procedure for PTH quality control by way of its unilateral heating, for example, by a laser beam.

scholarly journals Research on the calibrated method for MEMS magnetometer arrays

2020 ◽  
Author(s):  
Zetao Guo ◽  
Xiang Xu ◽  
Tao zhang
Keyword(s):  
Printed Circuit Board ◽  
Experimental Tests ◽  
Measurement Model ◽  
General Purpose ◽  
Circuit Board ◽  
Test Results ◽  
Adaptive Kalman Filter ◽  
Unknown Parameters ◽  
Printed Circuit ◽  
Magnetometer Arrays

The MEMS magnetometer determines the orientation for the MEMS inertial system. Because of the large noise of the MEMS magnetometer and the interference of soft and hard iron outside, the measurement error of the MEMS magnetometer is large. To reduce the effects of the random noises, the MEMS magnetometer arrays are designed in this paper. In our design, thirty-two MEMS magnetometers are welding on a printed circuit board (PCB), which area is 5×5 cm2. The forty general-purpose input-output (GPIO) ports, which are thirty-two data ports and eight clock ports, are used to collect the data of MEMS magnetometers. Then, averaging the thirty-two measurements of the MEMS magnetometers, the random noises of the measurements of the MEMS magnetometers can be reduced. Based on the averaging operation for the collected sensors’ data, a unified measurement model for the MEMS magnetometer arrays is constructed. Using the unified measurement model, an adaptive Kalman filter is developed to estimate the unknown parameters. To validate the performance of the MEMS magnetometer arrays, the simulation and experimental tests are designed. The test results show that, comparing with the single MEMS magnetometer, the random noises of the MEMS magnetometer arrays are reduced effectively.

Macro and Micro Thermal Model of an Elevated Temperature Dielectric Breakdown in Printed Circuit Boards

1996 ◽  
Author(s):  
R. Stutzman ◽  
S. Sathe ◽  
B. Sammakia
Keyword(s):  
Thermal Model ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Dielectric Breakdown ◽  
Dielectric Material ◽  
High Current Density ◽  
Thermal Modeling ◽  
Circuit Board ◽  
Printed Circuit ◽  
Defect Site

Abstract A computational macro and micro thermal model of a printed circuit board dielectric breakdown due to local and global heating of the laminate material is presented in this paper. On a macro level, under certain conditions, the circuit board temperature can approach the glass transition temperature (Tg) due to electronic surface mounted components dissipating heat to the board surface. Under these conditions interfacial micro cracks or dielectric inhomogeneities can be aggravated to an extent where localized voltage breakdown can occur across copper planes within the board. The micro thermal modeling results demonstrate that even under relatively high defect resistance levels the localized temperature at the defect site can greatly exceed the Tg of the dielectric material resulting in carbonization and eventually catastrophic failure. A temperature profile at the defect site clearly shows the spike in the local temperature due to the low thermal conductivity properties of the dielectric material and the localized high current density. The thermal modeling was performed using Flotherm (trademark of Flomerics Limited) code.

General Purpose Silicon Trigger Board for the CMS Pixel Read Out Chips

2010 ◽  
Vol 4 (1) ◽  
Author(s):  
E. Stachura ◽  
C.E. Gerber ◽  
R. Horisberger
Keyword(s):  
Compact Muon Solenoid ◽  
Printed Circuit Board ◽  
General Purpose ◽  
Circuit Board ◽  
Pixel Detector ◽  
Printed Circuit ◽  
Pixel Sensors ◽  
Paul Scherrer ◽  
Nuclear Instrument ◽  
Silicon Sensor

A semester research project was completed at Eidgenössiche Technische Hochschule Zürich (ETH Zürich) and the Paul Scherrer Institut (PSI) in the spring of 2010. A new kind of trigger based on silicon pixel sensors was developed for the commissioning of the current Compact Muon Solenoid (CMS) pixel detector. Prior to this trigger there was no silicon sensor based trigger that used the same technology as the pixel detector. The current trigger systems involve cumbersome photomultiplier tubes and Nuclear Instrument Module (NIM) crates to process the signals. To improve on these trigger systems it was thought to develop a trigger using pixel technology in the form of a printed circuit board that assimilates the signal processing circuitry. The board worked well, although there were limitations (e.g. crosstalk occurred so copper shielding was needed). A second generation trigger board currently exists. It fixes many of the problems encountered with the first board.

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.

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