Study On Thermal Analysis Of Electronic Circuits

Electronic equipment will produce the power dissipation after a period of time working and the temperature stay in a certain limited range. Some components are sensitivity to the temperature. If the heat is not be able to eject effectively, the heat flux density of PCB will stay high and even exceed the rated value, the component will be invalid. We call this heat waste. Thermal distress becomes an important factor in electronic products. What’s more, with the increase of temperature, the failure rate grows exponentially.We all know that thermal stability is very significant for designer. In the design of electronic circuit, most researches are base on the control of process. In this paper the board level layout of PCB will be introduced and the factor of thermal design, such as package, PCB, heat dissipation also be represented. The technological parameter and PCB parameter are not involved. What’s more, the same power density is proposed to layout the PCB. Compare with simulate annealing algorithms and the same power density, the latter get the best effect. And at last, the optimization results are analyzed. All the papers base on the follows in thermal design.The prolegomena mainly introduce the different between domestic and overseas. As the power density becomes large, the temperature of Printed circuit board (PCB) rises higher. The chip size, PCB’s integration level and package parameter are all can increase the power density. The design principle of PCB is to reduce the power density. In the thermal design, the material parameter of PCB, packaging parameter, technological conditions are related. Often the design consists of the board level, the package level and the system level three aspects.The thermodynamics and hydromechanics are applied in thermal design. Because of its resistance, PCB component produce the heat consumption. The energy flows through thermal conductivity, convection and radiation. The heat of PCB component may conduct to the PCB, convection to the adjacent component and radiate to the nearby component. The equations are usually higher order in theory. It is very difficult to solve. The finite difference methods are used to handle the equations. The parameter of packaging and PCB are the key factors in thermal design. The packaging technique, parameter, material of PCB are stated systematically. The principle of selecting radiator and designing component are also represented in this article.In this article, the PCB with the area of 5cm×5cm and the component with the area of lcm×1cm are chose as the object to research that how the layout effect the component temperature. Firstly, distribute the component in the same distance, and then on the base of thermal design theory in chapter two the mathematical modeling is built and use the finite difference method to analyze each component temperature in equally spaced position. And then applying the same power density and simulate annealing algorithms that every device’s power density divide each area can get the same result to layout. After solving the two device layout, the device’s highest temperature is decreased obviously and the former is better than the latter in cooling. The difference between the two methods is that the former change the distance among the components. However, the latter just move in position. Therefore, the former can get better results.