PCB enhanced heat dissipation method
(1) Heating of electronic components
(2) The heat of the PCB itself
(3) The heat from other parts
Among the three heat sources, the component generates the largest amount of heat, which is the main heat source, followed by the heat generated by the PCB board, and the external heat input depends on the overall thermal design of the system. This article focuses on the intensive cooling method of the PCB itself. ENIPIG HDI manufacturer china.
Standing on the perspective of thermal design, we pay attention to its own thermal conductivity. The PCB is a layered composite structure consisting of FR4 and Cu. The thermal conductivity difference between the two is very large, showing an anisotropic thermal conductivity. The summary features are as follows:
1) The PCB is a layered composite structure composed of FR4 and copper. Among them, FR4 thermal conductivity 0.3W / (m * K), copper thermal conductivity 380W / (m * K).
2) The main factor affecting the overall thermal conductivity of the PCB is the copper content. Generally speaking, the Power layer and the Groud layer contain more than 90% of the copper, while the trace layer is about 20%. The number of layers and the thickness are all factors that affect the overall copper content. RIGID-FLEXIBLE BOARD supplier.
3) High thermal conductivity in the plane of the PCB, generally in the range of 10 to 45 W / (m * K)
4) The thermal conductivity in the normal direction of the PCB is very low, around 0.3W / (m * K).
5) For thermal simulation, a simplified PCB model can be used. Simply set the copper content of the PCB. The ordinary PCB contains 10% copper, and the power amplifier board is set at about 30%.
6) When a refinement design is required, a detailed model can be built for the PCB, and each layer is refined and constructed using a detailed model. Of course, in order to solve the speed, it is also possible to calculate the exact copper content by establishing a detailed model and design with a simplified PCB model. The commonly used thermal design software Flotherm and 6SigmaET support board-level detailed modeling, such as FloEDA function. Single Side PCB manufacturer china.
Knowing the structure and characteristics of the PCB, it is natural to know how to enhance the heat dissipation of the board. Simply put, it is to increase the copper content of the PCB. First, increasing the amount of copper will increase the plane thermal conductivity, reduce the thermal resistance of the plane diffusion, allow the heat to spread faster, and then pass the convection and radiation to the environment. Secondly, through the local strengthening measures, the thermal conductivity of the QFN-like packaged devices to the PCB is enhanced. Such devices have a pad on the surface of the PCB, and the main purpose is to enhance the heat transfer resistance to the pad side.