Inductors have many important functions in circuit boards, which can solve the following problems:

1. Power supply filtering

-In the power supply circuit, inductor and capacitor can form a filter circuit to filter out high-frequency noise in the power supply. For example, at the output of switching power supply, high-frequency switching noise is often mixed with direct current. Inductor presents high impedance to high frequency signals, which can prevent high frequency noise from passing through and make the output DC voltage smoother and more stable. This is helpful to provide pure power for subsequent electronic devices (such as microprocessors, amplifiers, etc.) and avoid abnormal operation of devices caused by power noise, such as data errors or program runaway in microprocessors.

2. Signal filtering

For signal lines, inductors can be used to filter out unwanted signal frequency components. For example, in radio frequency (RF) circuits, inductors can be used as components of bandpass or bandstop filters. In a communication line containing multi-frequency signals, by reasonably designing the combination of inductance and other components (such as capacitors), only signals in a specific frequency band can pass through, and interference signals in other frequency bands can be suppressed, thus improving the quality of signals and the accuracy of transmission.

1. Store energy in switching power supply.

Inductor is a key energy storage element in switching power supply. During the conduction of the switch tube, the inductance stores energy, the current rises linearly, and the electric energy is stored in the form of magnetic field energy. When the switch tube is turned off, the inductor releases the stored energy to maintain the stability of the output voltage, so that the power supply can still maintain a relatively stable output when the load changes. This energy storage and release mechanism can effectively improve the efficiency of power supply, reduce energy loss, and can adapt to different load requirements.

2. In DC-DC converter.

-In DC-DC converter circuits such as Buck or Boost, the inductor uses its energy storage characteristics to realize voltage conversion. Take the Boost circuit as an example, the inductor charges and stores energy during the on-state of the switch, and releases energy to the output capacitor and load during the off-state of the switch, thus increasing the output voltage. This energy conversion process is very important for electronic devices that need different DC voltage levels to supply power (such as boosting the battery voltage in mobile devices to supply power to other modules).

1. Suppression of electromagnetic interference (EMI) emission

Inductors can suppress electromagnetic radiation generated by high-frequency signals on the circuit board. When there is a rapidly changing current in the circuit (such as clock signal and high-speed data signal in digital circuit, etc.), electromagnetic interference will occur. Inductors connected in series with these interference sources can reduce the change rate of current, thus reducing the intensity of electromagnetic radiation. This helps the circuit board to meet the electromagnetic compatibility standards and avoid interference with the surrounding electronic equipment.

2. Electromagnetic interference (EMS) protection

-Inductors can be used as protective elements in circuits against external electromagnetic interference. When external interference signals (such as electrostatic discharge, lightning surge pulse, etc.) are coupled to the circuit board, the inductor can prevent or weaken these interference signals from entering the sensitive electronic component area, protect the chips, transistors and other components in the circuit from being damaged, and ensure the normal operation of the circuit board.