Experimental characterization of board conduction sheets (original) (raw)
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Solid-State Electronics, 2015
In order to help the electronic designer to early determine the limits of the power dissipation of electronic component, an analytical model was established to allow a fast insight of relevant design parameters of a multi-layered electronic board constitution. The proposed steady-state approach based on Fourier series method promotes a practical solution to quickly investigate the potential gain of multi-layered thermal via clusters. Generally, it has been shown a good agreement between the results obtained by the proposed analytical model and those given by electronics cooling software widely used in industry. Some results highlight the fact that the conventional practices for Printed Circuit Board modeling can be dramatically underestimate source temperatures, in particular with smaller sources. Moreover, the analytic solution could be applied to optimize the heat spreading in the board structure with a local modification of the effective thermal conductivity layers.
Advances in Engineering Software, 1995
This paper provides an overview of the solution and application of the threedimensional heat conduction equation for a rectangular-shaped, multilayer structure with discrete surface heat sources. A Fourier series expansion is used to represent both the heat source function and temperature solution. Trigonometric terms are used for the two planar coordinates whereas the Fourier coefficient for the temperature expansion provides the dependence in the direction of the substrate thickness. Boundary conditions consist of insulated edges and Newtonian surface cooling. Application possibilities are numerous. A computer program based on this method has been used to analyze simple heat sinking chassis panels and finned extrusions with mounted power transistors. More elegant solutions are provided for many types of single and multi-chip packages, including hybrid circuit substrates. The prediction of printed circuit board conduction effects is also possible. Although the theory and a variety of applications of the resultant computer codes have been previously published in technical journals and symposia proceedings, this paper presents the most unified and complete review to date. NOTATION 2f b ci Substrate dimension in x-direction (m) Total area of finned heat sink (m2) Substrate dimension in y-direction (m) Substrate thickness up to and including layer i in z-direction (m) DH 4
Sensitivity of embedded component temperature to PCB structure and heat transfer coefficient
IEE Proceedings - Circuits, Devices and Systems, 2003
The sensitivity of embedded component temperature to the location of an embedded copper ground plane is investigated using computer simulation. The results show that the presence of a copper ground plane in close proximity to a component layer improves the potential packing density of components within the layer. Furthermore, placing a copper ground plane between two signal layers can reduce thennal interaction between components in the two layers by a factor of up IO. The layer density within a multilayer PCB is therefore improved, which again leads to a higher packing density of components. Using the results generated by the simulation, the authors then proceed to investigate the sensitivity of embedded resistor temperature to resistor size under different conditions of surface heat transfer. The results show that large embedded resistors are more sensitive to surface heat transfer than smaller ones and that small components are more effectively cooled by placing embedded copper ground planes in close proximity to them.
CHARACTERISATION OF CONDUCTIVE HEAT TRANSFER IN ELECTRONIC DEVICE-PACKAGES SOLID SYSTEMS
The heat conduction properties of device-package assemblies in electronic system can be experimentally characterised using a method based on the measurement of temperature transient curves after the power switching off. This technique, named TRAIT (Thermal Resistance Analysis by Induced Transient) yield the complete characterisation of row-like equivalent thermal circuit and therefore it allows the knowledge of the total thermal resistance of the system as a sum of several contributions due to the various parts of the assembling structure. This "spatial resolution" may be useful in failure analysis concerning the thermal reliability of multi-layer structures with several layer-layer interfaces. The theoretical background of the method is briefly exposed and some applications to both simulated and real devices are reported in order to demonstrate the capability of the method in revealing the differences of thermal conductive properties due to the parts of a heat conductive chain.
Substrate conduction mechanisms in convectively cooled simulated electronic packages
1991
An analytical model is developed for the conduction from a heated surface element to a conductive substrate or board. The interaction from neighboring components on the board is modeled by modifying the upper board surface temperature. A linear superposition technique is used to demonstrate that the base solution for an isolated component may be used to predict board-level behavior by modification of the driving temperature difference for board conduction. By comparison of the model with data for an array of 1.27 cm cubical elements on a mildly conducting substrate, it is shown that the use of the measured element's adiabatic temperature as a descriptor of the board temperature allows successful correlation of both single-element and surrounded-element conduction heat transfer with two geometric parameters
WIT transactions on engineering sciences, 1970
This paper provides an overview of the solution and application of the three-dimensional heat conduction equation for a rectangular-shaped, multilayer structure with discrete surface heat sources. A Fourier series expansion is used to represent both the heat source function and temperature solution. Boundary conditions consist of insulated edges and Newtonian surface cooling. Computer programs based this method are used to demonstrate the solution of a heat sinked hybrid circuit package mounted on an epoxy glass circuit board.
The cooling performance of heat spreading layers, consisting of materials that have relatively high thermal conductivity embedded into heat-generating mediums, presents itself as a viable method of reducing peak operating temperatures in, for instance, integrated power electronic applications. In this paper the boundary condition associated with single-directional heat extraction during the cooling of a generalised rectangular, three-dimensional heat-generating volume is considered numerically. Numerically based correlations are given from which the cooling performance of a layered structure can be calculated. These correlations are based on data for large ranges in geometric dimensions, thermal conductivities, fraction of volume used for cooling purposes, and high interfacial resistance values.
Effect of heat source orientation on the thermal behavior of N-layer electronic board
International Journal of Thermal Sciences, 2016
The present work completes a range of analytical solutions that deal with the steady-state temperature calculations of a multi-layered structure heated by a single or multiple heat sources. Today, the surfacemount devices onto a printed circuit board are not only oriented vertically or horizontally, various angles have henceforth to be considered in thermal simulation to assess new placement design. Thus the problematic of heating sources, having any rotation, is solved to enlarge the capability of conventional analytical approaches for modeling more efficiently the thermal behavior of recent electronic boards. To demonstrate its relevance, the proposed analytical solution has been compared to numerical simulations on the case of a multi-layered electronic board submitted to different configurations of heating sources. The comparison shows a good agreement between analytical and numerical calculations to predict the centroid or average temperatures. The promoted analytical approach establishes a kit of practical expressions, easy to implement, which would be cumulated, using superposition principle, to help electronic designer to early detect excessive temperatures of components or board beyond manufacturer limits. The ability to eliminate bad concept candidates with a minimum of setup, relevant assumptions and low computation time can be more easily achieved.
20th International Workshop on Thermal Investigations of ICs and Systems, 2014
Electronic components are continuously getting smaller. They embed more and more powered functions which exacerbate the temperature rise in component/board interconnect areas. Their design optimization is henceforth mandatory to control the temperature excess and to preserve component reliability. To allow the electronic designer to early analyze the limits of their power dissipation, an analytical model of a multi-layered electronic board was established with the purpose to assess the validity of conventional board modeling approaches. For decades, a vast majority of authors have been promoting a homogenous single layer model that lumped the layers of the board using effective orthotropic thermal properties. The work presents the thermal behavior comparison between a detailed multi-layer representation and its deducted equivalent lumped model for an extensive set of variable parameters, such as effective thermal conductivities calculation models or source size. The results highlight the fact that the conventional practices for Printed Circuit Board modeling can dramatically underestimate source temperatures when their size is very small.
Analytical Model of Temperature Distribution Over an Electronic Circuit Board
2003
The thermal model of an electronic circuit board with installed heat dissipating components is presented as a two-dimension steady-state heat conduction problem with multiple sources distributed over a rectangular region. The corresponding energy equation includes a source term and a temperature-dependent term to account for linear heat transfer in z-direction. Boundary conditions are of first type with unique temperature along the perimeter. The integral-transform technique is applied to obtain closed-form integral solution. Assuming that all dissipated components have a rectangular contact area with the plate, multiple integrals for each dissipated sub- region are easily found. A temperature map over the board is calculated from the closed expression with a triple sum of series with respect to each coordinate and source. The error is evaluated by the estimation of the truncated terms. The solution was applied to obtain the temperature distribution over the electronic Driver Plate ...