The role of magnetic ring inductance and common application introduction -
The inductor is one of the commonly used components in circuit design. It can form an LC filter network with the capacitor C, form a freewheeling function with the diode in the step-down circuit, and can also be used in the LC resonant circuit. Common applications of inductors are described below. 1. Use capacitors to form a liquid crystal filter circuit. As we all know, inductance can pass DC and resist AC, because the inductance of the inductor has a great relationship with the AC frequency. The greater the frequency, the greater the inductance. As shown in the figure below, it is the most commonly used circuit structure of switching power supply, and the inductor and capacitor act as filters. The AC ripple in the circuit will be filtered by the inductor and capacitor C to make the rear-end output smoother. This is typically used in switching power or high power applications. 2. Used in DC/DC step-down circuits DC/DC step-down chips have a wide input range and high conversion efficiency. The circuit principle of DC/DC step-down chips is generally realized through inductors, capacitors and diodes. As shown in the figure below, it is an ordinary DC/DC power supply chip, in which the inductor and diode form the freewheeling function. When the internal MOS tube is turned on, the inductor stores energy; when the internal MOS tube is turned off, the inductor can supply power to the load. This is also the most commonly used PWM step-down principle at present. 3. Used in LC resonance circuit LC can form series resonance or parallel resonance, which is also called frequency selection, that is, among many input frequencies, only those that are consistent with the resonance frequency can pass. This circuit is commonly used in radio, television, and other applications. When designing an LC resonant circuit, extensive calculations are required to determine the optimal parameters of the inductor and capacitor. The magnetic ring inductance is a coil with a magnetic ring. Because the coil has an inductive reactance to the alternating current after it is energized, it constitutes an electronic component - an inductor! Its inductance value ranges from 0.00 to 10 millisin. Originally, only the coil can form the inductance, but in order to increase the inductance, reduce the volume and DC resistance of the wire, a ferrite core with the smallest eddy current loss is added. For example, if a magnetic core with a permeability of 100 is added to a coil of 1 micron, the inductance is theoretically increased by 100 times and becomes 100 micron. But the actual increase is not only the magnetic permeability, but also related to the shape of the magnetic core (in addition to the ring, there are also cylindrical, square, bar, king, mouth, etc.). High-frequency AC circuits generally use less than tens of milliseconds The core inductance. The inductance of AC circuits below a few hundred hertz is more than a few hundred milliseconds-enjoy. It is not suitable to use magnetic cores, use microcrystalline, slope film alloys, or even silicon steel sheets! The volume and weight are much larger! Do not add iron cores where the inductance quality Q is extremely high. Inductive components are mainly used in resonant circuits, bandpass filters and bandstop filters. According to design requirements, the circuit is composed of tuning circuit, frequency selector, notch filter, filter, high frequency and intermediate frequency transformers, anti-interference circuit, damping circuit, spark elimination circuit, energy storage circuit, bridge and so on. Commonly used for filtering and anti-jamming!