PCB Blog - PCB Design: Solve Problems, Reduce Costs, Improve Performance

There are many issues to consider during the design of printed circuit boards, and tools, including DesignSpark PCB, can handle most of them efficiently. By adopting certain practical guidelines, engineers can effectively reduce costs and improve board reliability while meeting system specifications, deflecting the system at a lower cost and avoiding more problems. Designing a printed circuit board refers to the circuit layout through the design of the schematic drawings, and the production of the printed circuit board at the lowest possible cost. In the past, this was usually done with the help of expensive specialized tools, but now, the increasing availability of high-performance software tools such as DesignSpark PCB and design models has greatly accelerated the design speed of circuit board designers. While engineers know that a perfect design is the way to avoid problems, it's still a waste of time and money, while addressing the symptoms rather than the root causes. For example, if a problem is discovered during the electromagnetic compatibility (EMC) testing phase, it will cause a lot of cost investment, and even the original design will need to be adjusted and reworked, which will take several months.

Layout is one of the first problems designers face. This question depends on parts of the drawing, some equipment needs to be set together based on logic considerations. It should be noted, however, that temperature-sensitive components, such as sensors, should be located separately from heat-generating components, including power converters. For designs with multiple power settings, 12-volt and 15-volt power converters can be placed in different locations on the board, as the heat and electrical noise they generate can affect other components and the reliability and performance of the board . The above components will also have an impact on the electromagnetic performance of the circuit design, which is not only very important for the performance and energy consumption of the circuit board, but also has a great impact on the economy of the circuit board, so all circuit board equipment sold in Europe All must be CE marked to demonstrate that they will not interfere with other systems. However, this is usually only from the power supply side, and there are many devices that emit noise, such as DC-DC converters, and high-speed data converters. Due to imperfect circuit board design, this noise can be captured by the channel and radiated as a small antenna, creating spurious noise and frequency anomalies. Far-field electromagnetic interference (EMI) problems can be solved by adding filters at the noise point or shielding the signal with a metal enclosure. However, paying enough attention to the equipment that can emit electromagnetic interference (EMI) on the circuit board allows the circuit board to choose a cheaper casing, which effectively reduces the cost of the whole system.

Electromagnetic interference (EMI) is indeed a factor that has to be taken into account in the design process of PCB board. Electromagnetic crosstalk can couple with the channel, scramble the signal into noise and affect the overall performance of the board. If the coupling noise is too high, the signal may be completely covered, so a more expensive signal amplifier must be installed to restore it to normal. However, if the layout of the signal lines can be fully considered at the beginning of the design of the circuit board, the above problems can be avoided. Since the design of the circuit board will vary according to different equipment, different places of use, different heat dissipation requirements, and different electromagnetic interference (EMI) conditions, the design template will come in handy at this time. Capacitance is also an important issue in circuit board design that cannot be ignored because it affects the speed of signal propagation and increases power consumption. Channels can couple to adjacent traces or traverse two circuit layers vertically, inadvertently forming a capacitor. This problem can be solved relatively easily by reducing the length of the parallel lines, adding a kink to one of the lines to break the coupling, etc. However, this also requires engineers to fully consider production design principles to ensure that the design is easy to manufacture, while avoiding any noise radiation caused by the excessive bending angle of the line. It is also possible that the distance between the lines will be too close, which will create short loops between the lines, especially at the bends of the lines, and over time, metal "whiskers" will appear. Design rule inspection can usually be Areas with higher loop risk than normal are marked. This problem is particularly prominent in the design of the ground plane. A metal circuit layer that potentially couples to all traces above and below it. Although the metal layer can effectively block noise, the metal layer also generates an associated capacitance, which affects the running speed of the circuit and increases the power consumption. As far as the design of multi-layer circuit boards is concerned, the design of through holes between different circuit board layers may be a controversial issue, because the design of through holes will bring many problems to the production and manufacture of circuit boards. The through holes between the circuit board layers will affect the performance of the signal and reduce the reliability of the circuit board design, so it should be given full attention.

Solution: There are many different approaches that can be taken to solve various problems during the design of a printed circuit boards. Among them are the adjustment of the design scheme itself, such as adjusting the circuit layout to reduce noise; there are also methods in the layout of the printed circuit board. Design components can be automatically installed by the layout tool, but the ability to manually adjust the automatic layout will help improve the quality of the board design. Through this measure, design rule checking will rely on technical documentation to ensure that the board is designed to meet the board manufacturer's requirements. Separating the different board layers can reduce the associated capacitance, however, this increases the number of layers on the board, which increases cost and introduces more through-hole issues. Although the use of an orthogonal grid power system and ground trace design may increase the physical size of the board, it can effectively use the ground plane in a two-layer circuit board to reduce capacitance and circuit board manufacturing complexity. Design tools, including DesignSpark PCB, can help engineers solve many problems at the beginning of design, but engineers still need to have a good understanding of the design requirements of printed circuit boards. For example, if the editor of the printed circuit board needs to know the number of layers of the circuit board at the beginning of the design, for example, a double-layer circuit board needs to have a ground plane and a power plane, two composed of independent layers.

The use of automatic component placement technology is very useful, which can help designers spend more time designing the layout area of the device. For example, if the power supply device is too close to sensitive signal lines or areas with high temperature, Many problems will arise. In the same way, signal lines can also be automatically routed while avoiding most problems, however, analysis and manual manipulation of high-risk areas will help greatly improve the quality and profitability of printed circuit board designs, reduce the overall cost. Design rule checking is also a very powerful tool for checking the lines to ensure that the distances between the lines are not too close, resulting in a loop that is too short. However, the overall design still has a high economic value. Design planning inspection tools can also be used to inspect and adjust power and ground planes to avoid large parasitic capacitance areas. The tools described above will also be of great help to Gerber and Excellon as they perform wiring and board printing, as well as through-hole drilling, in order to produce the final design. In this way, the technical file is closely linked to the board manufacturer.

There are many issues to consider during the design of a printed circuit board, and tools, including DesignSpark PCB, can handle most of them efficiently. By adopting certain practical guidelines, engineers can effectively reduce costs and improve board reliability while meeting system specifications, deflecting the system at a lower cost and avoiding more problems with printed circuit boards.