Inductance is the ratio of the magnetic flux through a particular circuit to the current that is generating that magnetic flux.
In the case where the magnetic flux which indicates the size of the electromagnetic induction is produced by the current of the circuit itself is called self-inductance, and when produced by the current of other circuits is called mutual inductance, and inductance is used in meaning of self-inductance in many cases.
The Q (Quality factor) of an inductor indicates the quality characteristic of a coil.
The higher Q indicates the lower amount of resistance, if the frequency and inductance are fixed.
This is expressed by the following formula.
A choke coil is an electronic component that inhibits the passage of a high-frequency current.
DC resistance is the resistance value when measured with a direct current. When the resistance value is large, the power loss becomes larger.
The self-resonant frequency (SRF) is the frequency at which the distributed capacity of the inductor and the inductance resonate.
It does not function as an inductor beyond the resonance frequency.
The DC superimposition characteristics are the variations in characteristic values when a DC current is applied. The current when the inductance falls to a certain level is called the "saturation current."
The allowable current / rated current is the maximum value of the DC current that can flow through an inductor. There is the allowable current (Itemp) based on the temperature rise and the rated current (Isat) based on the inductance variation.
The operating temperature range is the allowable range for the ambient temperature when using an inductor. Self-heating is not included in the operating temperature range.
Ferrite is a generic name for a ceramic that is mainly composed of iron oxide.
The magnetic shield refers to the insulation against electrostatic, magnetic or electromagnetic waves from other electronic equipment, by covering the electronic equipment or a portion of the equipment with a conductor, conductive material or magnetic material.
Magnetic flux occurs when a magnetic field is applied to a magnetic material, such as ferrite.
The inductance value of the inductor is determined according to the occurrence level of this magnetic flux.
When the magnetic field becomes larger, the level of increase in the magnetic flux to the magnetic field is decreased, and even though the magnetic field is increased, the magnetic flux will not increase. This is a phenomenon called the magnetic saturation of the magnetic material.
When considering from the level of the inductor component, when the current flowing to the inductor is increased, the magnetic field will also increase which generates the magnetic saturation of the magnetic material. As a result, the inductance value drops.
The magnetic saturation characteristics of the inductor are influenced by the type and structure of the magnetic material used by the inductor, and a large current flows through the inductor used in power supply systems, therefore, it is important to confirm if magnetic saturation tends to be generated. In order to confirm the level of this tendency, the DC superimposing characteristics of the inductor are used as a reference.
Magnetic coupling refers to the state in which circuits are affected by the magnetic flux created by other circuits.
The magnetic flux generated in the inductor does not only remain within the magnetic material, such as the ferrite, and leaks into a portion of the external space. This leaked magnetic flux is called leakage flux. It is necessary to pay attention as the magnetic flux distribution of the inductor may change when magnetic materials, such as structural components approach the portion with the leakage flux, which changes the performance. Also, when interference occurs with the leakage flux of other components, a jump transfer may occur by the magnetic coupling of the signal. In order to reduce leakage flux, there are inductors that are protected by a magnetic shield structure.
The ripple voltage in a DC-DC converter is the minute voltage fluctuation component included in the output voltage.