Chipinductors, also known as power inductors, high-current inductors and surface-mounted high-power inductors. It has the characteristics of miniaturization, high quality, high energy storage and low resistance.
Selection principle of patch inductance
In order to select inductors for portable power supply applications, the three most important points are size, size, and the third is size. The circuit board panel of mobile phone is very compact, especially with the increase of various functions such as MP3 cute player, TV and telephone. The increase of functions will also increase the current consumption of the battery. Therefore, the previous modules powered by linear regulators or directly connected to batteries need more efficient solutions. The first step to a more efficient solution is to use a magnetic buck converter. As its name suggests, an inductor is needed at this time.
In addition to the size, the main specifications of inductors include the inductance value at switching frequency, coil DC impedance (DCR), rated saturation current, rated rms current, AC impedance (ESR) and Q factor. Depending on the application, the choice of inductor type, shielded or unshielded, is also important.
Similar to the DC bias in capacitor, the 2.2μH inductor of manufacturer A may be completely different from that of manufacturer B. The relationship between inductance and DC current in the relevant temperature range is a very important curve, which must be obtained from manufacturers. The rated saturation current (ISAT) can be found on this curve. ISAT is generally defined as the DC current when the inductance value drops by 30[[%]] of the rated value. ISAT is not specified by some inductor manufacturers. They may only give the DC current when the temperature is 40℃ higher than the ambient temperature.
Matters needing attention in chip inductance
(1) When using inductors, attention should be paid to humidity and dryness, ambient temperature, high-frequency or low-frequency environment, and whether inductors show inductive or impedance characteristics;
(2) Frequency characteristics of the inductor. At low frequency, the chip inductor generally presents the characteristics of inductance, high energy storage and high filtration. But at high frequency, its impedance characteristic is remarkable. There are some phenomena, such as energy consumption, fever, and decrease of perceptual effect. The high frequency characteristics of inductors are different;
(3) The large current and corresponding heating that the inductor should bear;
(4) When using the magnetic ring, find out the corresponding L value and the application range of the material by comparing the magnetic ring part above;
(5) Pay attention to the wires (enameled wire, wrapped wire or naked wire) and commonly used enameled wire. Find the most suitable line;
