What are the grounding methods for PCB board circuits?Rigid Flex PCB Fabrication_Shenzhen StarLight Industrial Development Co., Ltd.

What are the grounding methods for PCB board circuits?Rigid Flex PCB Fabrication

source:Other information release time:2023-08-24 Hits: Popular:PCB Assembly company: Share:

　　In PCB design, grounding is an important measure to suppress noise and prevent interference. According to different circuits, there are different grounding methods, and only correct grounding can reduce or avoid mutual interference between circuits. So, what are the grounding methods for PCB board circuits? Next, let professional engineers explain for you:

　　1. Single point grounding

　　Single point grounding refers to the entire system where only one physical point is defined as the grounding reference point, and all other points that require grounding are connected to this point.

　　Single point grounding is suitable for circuits with lower frequencies (below 1MHz). If the working frequency of the system is so high that the working wavelength can be compared to the length of the system grounding lead, the single point grounding method is problematic. When the length of the ground wire is close to 1/4 wavelength, it is like a transmission line with a short circuit at the end. The current and voltage of the ground wire are distributed as standing waves, and the ground wire becomes a radiation antenna and cannot function as a "ground".

　　For PCBs that are widely used in digital circuits, due to their rich high-order harmonics, it is generally not recommended to use a single point grounding method.

　　2. Multi point grounding

　　Multipoint grounding refers to the direct connection of each grounding point in the equipment to the nearest grounding plane, in order to minimize the length of the grounding lead.

　　The multi-point grounding circuit has a simple structure and significantly reduces the high-frequency standing wave phenomenon that may occur on the grounding wire, making it suitable for occasions with high operating frequencies (>10MHZ). However, multi-point grounding may lead to the formation of many grounding loops inside the equipment, thereby reducing its resistance to external electromagnetic fields. In the case of multi-point grounding, attention should be paid to the issue of ground loops, especially when networking between different modules and equipment.

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