The electromagnetic compatibility design mainly includes surge (impact) immunity, ringing wave surge immunity, electrical fast transient burst immunity, voltage sag, short-term interruption and voltage change immunity, power frequency power supply Harmonic immunity, electrostatic immunity, radio frequency electromagnetic field radiation immunity, power frequency magnetic field immunity, pulse magnetic field immunity, conducted disturbance, radiated disturbance, conducted immunity induced by radio frequency field, etc. .
At present, the deteriorating electromagnetic environment makes us gradually pay attention to the working environment of the equipment, and pay more and more attention to the influence of the electromagnetic environment on electronic equipment. Starting from the system design, including the subsequent structure and PCB design, we must fully consider the EMC problem and integrate the electromagnetic environment. Compatible design makes electronic devices work more reliably.
The electromagnetic compatibility design mainly includes surge (impact) immunity, ringing wave surge immunity, electrical fast transient burst immunity, voltage sag, short-term interruption and voltage change immunity, power frequency power supply Harmonic immunity, electrostatic immunity, radio frequency electromagnetic field radiation immunity, power frequency magnetic field immunity, pulse magnetic field immunity, conducted disturbance, radiated disturbance, conducted immunity induced by radio frequency field and other related designs.
The main form of electromagnetic interference
Electromagnetic interference mainly enters the system through conduction and radiation, which affects the work of the system. Other ways include common impedance coupling and inductive coupling. Conduction: Conduction coupling is the coupling of disturbances on one electrical network to another electrical network through a conductive medium, which is a lower frequency part (below 30MHz). The paths of conduction coupling in our products usually include power lines, signal lines, interconnect lines, ground conductors, etc.
Radiation: The disturbance on one electrical network is coupled to another electrical network through space, which belongs to the higher frequency part (above 30MHz). The way of radiation is transmitted through space, and the radiation interference introduced and generated in our circuit is mainly the antenna effect formed by various wires.
Common Impedance Coupling: Mutual interference that occurs when currents from two or more different circuits flow through a common impedance. Disturbance currents conducted on power lines and ground conductors are mostly introduced into sensitive circuits in this way.
Inductive coupling: Through the principle of mutual inductance, the electrical signal transmitted in one loop is induced to interfere with another loop. Divided into two kinds of electric induction and magnetic induction.
Corresponding countermeasures that we should take for the interference generated by these several ways: filter the conduction (for example, the on-chip capacitor of each IC in our design plays a filtering role), and reduce the antenna effect for radiation interference (such as the signal is close to the ground wire), Measures such as shielding and grounding can greatly improve the product’s ability to resist electromagnetic interference, and can also effectively reduce electromagnetic interference to the outside world.
Electromagnetic Compatibility Design (Electromagnetic Compatibility Design in PCB)
For the R&D and design process of a new project, the electromagnetic compatibility design needs to run through the whole process. Considering the electromagnetic compatibility design in the design, it will not be reworked, and repeated R&D will be avoided, which can shorten the time-to-market of the entire product and improve the efficiency of the enterprise.
From research and development to market launch, a project needs to go through several stages such as demand analysis, project approval, project outline design, project detailed design, sample trial production, functional testing, electromagnetic compatibility testing, project production, and market launch.
In the demand analysis stage, it is necessary to carry out product market analysis, on-site research, excavate useful information for the project, integrate the development prospects of the project, sort out the working environment of the project products in detail, inspect the installation location on the spot, whether there is limited space for installation, and whether the working environment is special, Whether there is corrosion, humidity, high temperature, etc., the working conditions of the surrounding equipment, whether there is a harsh electromagnetic environment, whether it is restricted by other equipment, whether the successful development of the product can greatly improve the production efficiency, or whether it can provide people with a living or working environment. It brings great convenience and whether the operation and use methods are easy to be accepted by people. This requires the project products to meet the needs of on-site functions and easy to operate, and finally to organize a detailed demand analysis report for demand review. Electromagnetic Compatibility Design in PCB.