pcb design technology

Generally, designers only pay attention to the best technology of power components and maximize energy use. But they forgot to study the best PCB solution and its best electronic component arrangement. Recently, the project has been based on a highly integrated component that can withstand the power of large work. High current and voltage management requires very complicated technical challenges. Printing circuit boards are the first obstacles that must be passed by heat, and they need to be designed in the best way.

Designers must consider all aspects, for example, the best position and best distance between the track. The most important thing is that they can bear the ability of high current while running in the best way. The first basic rule involves preliminary way to highlight the maximum power path and the power components that will fill them. In fact, the track will be affected by high temperature, and due to the high electrical and thermal conductivity of copper, high temperature can easily invade all areas of the circuit. In order to complicate the calculation and analysis of the wiring, there are other parameters, such as the materials used by PCB, the environmental temperature of the design around the design, the density of the component on the board, and the cooling technology used. Non -success or failure. Those who work under particularly critical thermal conditions must be evenly distributed on the circuit to improve thermal management. Designers must pay special attention to the path of the track. The minimum width of the slope related to the current and the temperature of the current must be considered. If possible, compared with the technical minimum width, it is always better to increase the width of the orbit slightly. The calculation of the wiring involves not only its width, but also the thickness of copper. The collector with large copper thickness allows their width to reduce their width under the same conditions. The following table (see the chart with a large copper thickness set pipe allows the width of them under the same conditions. The following table (see the chart with large copper thickness, allowing the width of them under the same conditions. The table below is below. (See Chart 2) Show the minimum width of the printing circuit line, know that the current must be passed through it. The same table refers to a PCB with a copper thickness of 35 microns, and the maximum expected temperature rising to 10 ° C is 10 ° C

Figure 2: This figure shows the width related to the current in the transmission

Obviously, the use of more than 10 A is more convenient to use other methods than using simple PCB. A convenient formula that the designer can use, remember to use the copper thickness of 35 microns, as shown below:

In Figure 3, we can observe some of the various widths of the PCB wiring compared with the USB disk. The diagram also shows the diameter of the most common cables and the current they support.

Figure 3: PCB tracks and cables of different sizes

On the other hand, Figure 4 shows the hypothetical PCB simulation formed by the bronze traces of different widths. Through the same current value, they have different working temperatures, although they have been cooled by the same convection. In short, it can be seen that the wider rails remain cold, and the current of transmission and convection cooling is the same.

Figure 4: When the same number of current flows, different behaviors of copper traces in PCB.

The first is the power conversion efficiency. The conversion efficiency refers to the ratio of the output power of the power supply to the input power of actual consumption. In actual applications, the power cannot be fully transformed, and there will be a certain energy consumption in the middle. Therefore Essence For linear power supply, the heat dissipation problem of LDO needs to be considered; for the switching power supply, the loss of the switching tube must be considered. Secondly, energy loss will inevitably produce heat, which involves the problem of heat dissipation. In addition, as the load is heavier, the power consumption of power chips is increased. Therefore, heat distribution in power design is a problem that has to be considered. Furthermore is the design of power plane. Maintaining the integrity of the power is to maintain the stable power supply of the power. In the actual system, there are always no frequency noise. For example, the inherent frequency of PWM or the PFM variable frequency control signal, the fast DI/DT will generate a current fluctuation signal, so a low -impedance power graphic design is necessary. Finally, the EMI (electromagnetic interference) problem. The switching power supply will generate switch noise in the constant opening and level. If the circuit inductor problem is not considered during the design process, the excessive return path will cause EMI problems. Conclusion In the calculation and analysis of power circuits, cables and PCB are usually ignored. Designers should pay special attention to them, because effective design helps to avoid problems that cannot be solved without a solid preliminary preliminary preparation.