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Electronic Design

Electronic Design

Electronic Design

Electronic Design

PCB design core problem solution
2021-08-28
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Author:Belle

Carrying out printed circuit board (PCB) design refers to the principle of PCB design drawings, circuit planning, and consumption of circuit boards at the lowest possible cost. In the past, this was usually done with the help of expensive special tools, but now, with the increasing improvement of high-performance software tools and design models, the design speed of circuit board PCB designers has been greatly accelerated.
Although engineering designers know that a satisfactory pcb design plan is the best way to prevent problems from showing up, it is still a waste of time and money, and a cure for the root cause and not the symptoms at the same time. For example, if problems are found in the electromagnetic compatibility (EMC) testing phase, a large amount of capital investment will be formed, and even the initial design plan needs to be adjusted and re-manufactured, which will consume several months.
Planning is a problem that PCB designers must face first. This problem depends on the partial content in the drawing, and some devices are set together based on logical thinking requirements. However, it should be noted that components that are relatively sensitive to temperature, such as sensors, should be installed separately from components that generate heat, including power converters. Regarding the PCB design with multiple power settings, 12 volt and 15 volt power converters can be set in different positions on the circuit board. The heat and electronic noise they generate will affect the reliability and performance of other components and the circuit board. Influence.
The above components will also affect the electromagnetic performance of the circuit design. This is not only about the performance and energy consumption of the circuit board, but also has a great impact on the economics of the circuit board. Therefore, all circuit board equipment sold in Europe All must obtain the CE mark to prove that it will not interfere with other systems. However, this is usually only in terms of power supply, and there are many devices that emit noise, such as DC-DC converters, and high-speed data converters. Due to the defects in the PCB design of the circuit board, these noises can be captured by the channel and used as a small antenna to stop radiating, resulting in spurious noise and frequency abnormal areas.
The problem of far-field electromagnetic interference (EMI) can be dealt with by installing a filter at the noise point or using a metal casing to shield the signal. However, the full attention to the equipment that can release electromagnetic interference (EMI) on the circuit board has enabled the circuit board to choose a lower-priced housing, thereby effectively reducing the cost of the entire system.
In the PCB design process of the circuit board, electromagnetic interference (EMI) is indeed an element that has to be paid attention to. Electromagnetic crosstalk can be coupled with the channel, thereby disrupting the signal into noise and affecting the overall performance of the circuit board. If the coupling noise is too high, the signal may be completely covered up, so it is necessary to install an increasingly expensive signal amplifier in order to return to normal. However, if at the beginning of the design of the circuit board, the signal circuit planning can be fully considered, the above problems can be prevented. Since the design of the circuit board will vary according to different equipment, different application locations, different heat dissipation requirements, and different electromagnetic interference (EMI) conditions, the design template will come in handy.
Capacitors are also an important issue that cannot be ignored in circuit board design. Capacitors affect the propagation speed of signals and increase power consumption. The channel will be coupled with the line next to it or vertically traverse two circuit layers, thus unintentionally forming a capacitor. By reducing the length of parallel lines, adding a kink to one of the lines to cut off the coupling, etc., the above-mentioned problems can be handled relatively easily. However, this also requires engineering designers to fully consider the production design criteria, to ensure that the design plan is easy to manufacture, and to prevent any noise radiation caused by excessive line bending angles. The spacing between the lines may also be too close, which will produce short loops between the lines, especially at the bends of the lines, which will show metal "whiskers" over time. Design rule detection can usually indicate areas where the loop risk is higher than normal.
This problem is particularly prominent in the design of the ground plane. A metal circuit layer may form a coupling with all the lines above and below it. Although the metal layer can effectively block noise, the metal layer also generates associated capacitance, which affects the running speed of the circuit and increases the power consumption.
As far as the PCB design of multilayer circuit boards is concerned, the through-hole PCB design between different circuit board layers is probably the most controversial issue, because the through-hole design will bring many problems to the production and manufacture of circuit boards. The through holes between the layers of the circuit board will affect the performance of the signal and reduce the reliability of the circuit board design, so it should be paid attention to.

printed circuit board PCB design

Treatment plan:
In the printed circuit board PCB design process, many different methods can be adopted to deal with various problems. Among them, there are not only the adjustment of the design plan itself, such as adjusting the circuit plan to reduce noise; there are also methods for the planning of the printed circuit board. The design component can stop the automatic device through the planning tool, but if the automatic planning can be manually adjusted, it will help improve the quality of the circuit board design. After this measure, the design rule detection will rely on technical documents to ensure that the design of the circuit board can meet the requirements of the circuit board consumer manufacturers.
Separating different circuit board layers can reduce the associated capacitance. However, this will increase the number of layers of the circuit board, thereby increasing costs and bringing more problems with through holes. Although the use of an orthogonal grid power supply system and grounding circuit design may increase the physical size of the circuit board, it can effectively play the role of the ground layer in the double-layer circuit board, reducing the capacitance and the complexity of circuit board production.
Design tools including DesignSpark PCB can assist engineering designers to deal with many problems at the beginning of design, but engineering designers still need to have a sufficient understanding of printed circuit board (PCB) design requirements. For example, if a printed circuit board (PCB) editor needs to understand the number of layers of the circuit board at the beginning of the design, for example, a double-layer circuit board needs a ground layer and a power supply Layer, composed of two independent layers. The automatic component planning technology is very useful and can help designers spend more time to design the planning area of the equipment. For example, if the power supply equipment is too close to the sensitive signal line or the area with higher temperature, There will be a lot of problems. In the same way, signal lines can also stop automatic routing and prevent the appearance of most problems. However, stopping analysis and manual operation of high-risk areas will help greatly improve the quality of printed circuit board (PCB) design, Improve income and reduce overall costs.
Design rule detection is also a very powerful tool, which can stop the detection of lines to ensure that the spacing between the lines is not too close, thereby forming a loop that is too short. However, the overall PCB design still has high economic value. The design planning inspection tool can also be used to detect and adjust the power layer and ground layer to prevent the generation of large associated capacitance areas.
The above-mentioned tools will also bring great assistance to Gerber and Excellon, helping them to stop circuit and circuit board printing, as well as through-hole drilling, etc., in order to consume the final design waste. In this way, the PCB design technical file is closely linked with the circuit board manufacturer.
in conclusion:
Many problems need to be considered in the design process of printed circuit boards (PCB), and tools including Design Spark PCB can effectively deal with most of the problems. By adopting some of the best theoretical guidelines, engineering designers can effectively reduce costs and improve the reliability of circuit boards, while meeting the requirements of system specifications, with lower cost deflection system certification, so as to prevent more problems.