Analizė kondensatorius charakteristikos EMC projektavimas perjungimas maitinimas tiekimas
Daug elektroniniai dizaineriai know the role of filter kondensatoriai in power supplies, but the filter kondensatoriai used at the output end of switching power supplies are different from the filter kondensatoriai used in power frequency circuits. Common kondensatoriai used for filtering in power frequency circuits The pulsating voltage frequency of elektrolittic kondensatoriai is only 100 Hz, and the charge and discharge time is on the order of milliseconds. In order to gauti a mažas pulsacija koeficientas, the reikalaujama talpa is as aukštas as šimtai of tūkstančiai of microfarads. Todėl, paprastas aliuminis elektrolitiniai kondensatoriai yra paprastai pagaminti for low frequencies. The main goal is to improve the capacitance. The talpitance, loss tangent value and leakage current of the capacitor are the main parameters to identify its quality.
As an elektrolitinis kondensatorius for išėjimas filtravimas in a perjungimas galia tiekimas, the frequency of the sawtooth voltage on it is as high as tens of kilohertz or even tens of megahertz. Its requirements are different from those in low-frequency applications. Capacitance is not the main indicator. To measure it What is good or bad is its impedance-frequency characteristics, which require it to have low impedance within the operating frequency band iš the switching reguliuojamas power supply. At the same time, for the inside of the power supply, the peak noise of up to hundreds of kilohertz is generated by the semiconductor device starting to work. , can also have a good filtering effect. Generally, when ordinary elektrolittic kondensatoriai are used at low frequencies around 10 kHz, jų impedansas prasideda to pasirodyti indukcinis ir negali atitikti reikalavimai už perjungimas galia maitinimo šaltiniai.
It is a high-frequency aluminum electrolytic capacitor dedicated to switching power supply. It has four terminals. The two ends of the positive aluminum sheet are respectively led out as the positive electrode of the capacitor, and the two ends of the negative aluminum sheet are also respectively led out as the negative electrode. The current of the regulated power supply flows from one positive terminal of the four-terminal capacitor, passes through the capacitor, and then flows from the other positive terminal to the load; the current returned from the load also flows from one negative terminal of the capacitor, and then flows from the other negative terminal to the power supply. negative terminal.
Nes the four-gnybtas kondensatorius turi geras aukštas-dažnis charakteristikos, it suteikia an labai naudinga priemonės for redukcija the ripple component of the output voltage and suppressing switching spike noise.
Aukšto dažnio aliuminis elektrolitiniai kondensatoriai taip pat come in the form of multi-core, which divides the aluminum foil into several shorter segments and connects them in parallel with multiple lead-out sheets to reduce the resistance in the talpive reactance. At the same time, low-resistive materials are used and screws are used as leads. terminals to enhance the capacitor's ability to withstand large currents.
Laminated capacitors are also called non-inductive capacitors. Generally, the cores of electrolytic capacitors are rolled into a cylindrical shape, and the equivalent series inductance is large. The structure of laminated capacitors is similar to that of books. Because the direction of the magnetic flux generated by the flowing current is opposite, it is called Cancel, thus reducing the value of the inductance and having better high-frequency characteristics. This kind of capacitor is generally made into a square shape, which is easy to fix and can also appropriately reduce the volume of the machine.
In addition, there is a four-gnybtai laminuotas aukšto dažnio elektrolitinis kondensatorius kad kombainai keturi-gnybtai ir laminacija, kuris kombainai the privalumai a a a high-frequency charakteristikos.
