An Investigation of the Relationship Between Packaging Density and Effective Thermal Conductivity in Laminated Printed Circuit Boards

摘要

An experimental and numerical investigation of the thermal behavior of fibreglass epoxy printed circuit boards with multiple copper layers and discrete, surface mounted heat sources in a vertical orientation with natural convection cooling is presented. Through a comparison of mesured and numerical values for three different heat source configurations, the effect of component density and power on the effective thermal conductivity for a single layer model is determined. Previous analytical work has suggested that this effective thermal conductivity is bounded by lower and upper limits defiend using the series and parallel conduction paths, respectively. however, the following investigation shows that when the fluid side resitance controls the heat transfer, as in natural convection cooling, the effective thermal conductivity required by various numerical and analytical solutions exceeds the previously defined upper limit and an alternate model is required.