Common mode choke is commonly used in computer switching power supply to filter common mode electromagnetic interference signals.
The common mode inductor is essentially a bidirectional filter. On the one hand, it needs to filter out the common mode electromagnetic interference on the signal line, and on the other hand, it needs to suppress the electromagnetic interference emitted by itself, so as not to affect the normal working electromagnetic environment of other electronic equipment in the same area.
In the design of the circuit board, the common mode inductor also acts as an EMI filter to suppress the electromagnetic waves radiated by high-speed signal lines.
The common mode inductor shall be made in accordance with the following requirements .
(1)The wires wound on the coil core shall be insulated from each other to ensure that there is no breakdown and short circuit between coils under the action of transient over-voltage;
(2)When the coil flows through the instantaneous large current, the magnetic core shall not be saturated
(3)The magnetic core in the coil shall be insulated from the coil to prevent breakdown under transient overvoltage
(4)The coil shall be wound in a single layer as far as possible to reduce the parasitic capacitance of the coil and improve the bearing capacity of the coil to the transient over-voltage
What are the requirements for common mode inductors? In general, pay attention to selecting the required frequency band, and the larger the common mode impedance, the better. Therefore, when selecting a common mode inductor, you need to check the device information, mainly according to the impedance frequency curve
Post time: Nov-24-2022