What is the role of common mode inductors? What is the selection method

Common mode inductors are commonly used to suppress common mode interference in circuits. Common mode interference refers to electromagnetic interference that affects two signals in a circuit simultaneously, usually from external environments or other circuits. In order to provide readers with a deeper understanding of the functions and choices of common mode inductors, this article will organize and briefly introduce relevant knowledge. If you are interested in the content covered in this article, please continue reading.

Efficiency of common mode inductors

Suppress common mode interference by providing a high impedance path. Common-mode inductors are typically placed between two power lines in a circuit and connected to a ground wire. When a common mode signal enters a circuit, it can be absorbed by a high impedance common mode inductor and energized through a ground wire. Therefore, common mode inductors can improve the anti-interference performance of the power supply and reduce signal distortion and noise.

In addition, common mode inductors can also be used as components of differential mode circuits to improve the performance and stability of power supplies. In differential mode circuits, common mode inductors can be used to maintain the input of the differential mode amplifier from common mode interference.

Selection Method of Common Mode Inductors

Inductance value: The inductance value should be selected according to the provisions of the power supply. In general, the larger the inductance value, the higher the common mode rejection ability.

Rated voltage: Select an appropriate rated voltage based on the operating current of the power supply to ensure the normal operation of the common mode inductor.

Resistance measurement: The lower the resistance measurement, the lower the power loss.

Frequency response: The frequency response of the common mode inductor should comply with the provisions of the power supply to ensure a good common mode suppression effect within the output power range.

Dimensions and packaging: The dimensions and packaging of common mode inductors should be suitable for the layout and installation specifications of circuit boards.

Therefore, when selecting a common mode inductor, it is necessary to carefully consider the circuit requirements and environment, and fully consider the above factors for selection. The appropriate common mode inductor can be determined by referring to the manufacturer's specifications and application guidelines.