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How to deal with the thermal reliability of PCB board?

How to deal with the thermal reliability of PCB board?

In general, the copper foil on the PCB board is very messy and difficult to model accurately.Therefore, it is necessary to simplify the configuration of wiring in modeling. The electronic components on the board of ANSYS model, which is close to the practical circuit board board board board, can also be simulated by simplified modeling, such as MOS pipe and integrated circuit block.

Thermal analysis of 1.

Thermal analysis can help planners determine the electrical function of the components on the circuit board, and help planners determine whether the components or circuit boards will burn out due to high temperature.The brief thermal analysis only calculates the average temperature of the circuit board, and the transient model should be set up for the electronic equipment with multiple circuit boards.The accuracy of thermal analysis ultimately depends on the accuracy of the power consumption of the components supplied by the PCB planner.In many USES medium component and physical size are very important, if the practical power consumption of components is small, it may cause the safety coefficient of planning to be too high, thus making the selection of circuit board planning inconsistent with the practice or too much saved component power value as the basis for thermal analysis.On the contrary (and more seriously), the thermal safety factor planning is too low, that is, the temperature of the practical operation of the components is higher than the analyst’s guess. Such problems are usually dealt with by cooling the circuit boards with the addition of cooling devices or fans.These external accessories increase the cost and prolong the production time. The participation of electric fans in the planning will also bring unstable factors to the reliability. Therefore, active rather than passive cooling methods (such as natural convection, conduction and radiation heat dissipation) are the primary choice for PCB boards.

  1. Simplified modeling of circuit boards

Before modeling, analyze the main heating equipment in the PCB board, such as MOS pipe and integrated circuit block, etc. These components convert most of the lost power into heat during operation.Therefore, the primary requirement for modeling is to think about these devices.In addition, also consider circuit board substrate, as a wire coated copper foil.In the planning, they not only have the effect of conducting electricity, but also have the effect of conducting heat. Their thermal conductivity and heat transfer area are relatively large.The thickness of epoxy resin substrate is 4mm, and the thickness of copper foil is 0.1mm.The thermal conductivity of copper is 400 W/m ℃), and the thermal conductivity of the epoxy resin was only 0.276 W/(m ℃).Although the added copper foil is very thin and thin, it has a strong thermal guidance effect, so it cannot be neglected in modeling.