This article will guide you to explore the main parameters of chip power inductors and how to select them. There are many parameters of inductors, and different manufacturers describe the parameters differently, this article will take TDK brand SPM4010 series wound power chip inductors as an example to deeply analyze the inductance parameters and selection skills.
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First of all, let's take a look at the main parameters of TDK brand SPM4010 series wirewound power chip inductors. This inductor is typically used in DCDC circuits. The main parameters include inductance, DCR (direct current resistance), accuracy (tolerance), ISAT (saturation current), ISPIKE (impulse current), and inductor frequency characteristics.
The inductance is an important parameter of the inductance, which is usually recommended by the DCDC chip manufacturer, and we only need to refer to the selection.
DCR (Direct Current Resistance) is the DC resistance of an inductor coil, and it is closely related to the amount of inductance. In the case of the same core, the greater the inductance, the more winding is required, resulting in an increase in DC resistance.
Accuracy (tolerance) is an important parameter that determines the range of error between the actual and nominal value of the inductance. Choosing the right accuracy according to the actual needs is a step that cannot be ignored in the selection process.
ISAT (saturation current) means that when the DC current flowing through the inductor gradually increases, the inductor core gradually enters a saturation state, and the inductance gradually decreases. The current when the inductance drops by 30% is called the saturation current. During the selection process, it should be noted that the definition of saturation current may be different for different manufacturers, and some manufacturers set it at 20%, so be careful when using them in different places.
Ispike (inrush current) means that when the current flowing through the inductor suddenly increases, the magnetic saturation phenomenon of the inductor core occurs, and the inductance decreases sharply. Therefore, when selecting an inductor, the maximum inrush current that can occur in the circuit should be taken into account.
Finally, let's take a look at the frequency characteristic curve of the inductor. This curve shows how the inductance changes as the frequency increases. In practice, if the switching frequency is only a few MHz at most, then this curve will not affect the selection.
In general, the selection of chip power inductors requires us to fully understand the meaning of each parameter and its impact on the circuit performance, and make a reasonable selection according to the actual needs. In this process, it is very helpful to have a certain knowledge of electricity and understand the product characteristics of different manufacturers.