![]() ![]() This is not a wire wound type but a type in which an air-core coil is encapsulated in the soft magnetic metal powder kneaded with binder (binding material) and integrally molded. The shield core has various shapes such as a ring type and an L-type, and the strength and distribution of magnetic flux leakage, as well as the cost vary, depending on the structure. However, magnetic shielding does not always provide complete encapsulation, and flux can leak from the air gap or terminal of the junction between the shield core and drum core. Although the magnetic shielding effect is limited, it has an advantage of cost reduction.Ī type made structurally closer to the closed magnetic path by covering around the drum core with ferrite shield core. Table 1 Types of power inductors in terms of magnetic shielding Non-shielded typeĪ type in which just simply a wire is wound around a drum core and a magnetic shielding is not provided.Ī type in which the wound drum core is encapsulated and molded with resin kneaded with magnetic powder such as ferrite or soft magnetic metal. Power inductors are categorized into the types shown below in terms of magnetic shielding ![]() Particularly, the leakage flux increases in power inductors in which large current flows, various magnetic shield structures are employed so that leakage of magnetic flux to the outside would not occur as much as possible. In electronic equipment, if the leakage flux of the inductor is magnetically coupled with another coil, wiring pattern, etc., inductance can change or noise may be caused. In the case of using rod-like or drum-like cores, the magnetic flux goes out of the inside of the core and becomes a leakage flux, which draws a loop returning to the core again. A magnetic circuit like this is called a closed magnetic path. When winding on a magnetic toroidal core (donut-like core) and applying current, the magnetic flux refluxes the inside of the core. Compared with multilayer-type, thicker copper wire can be used for it, which can support larger current. The mainstream of the products are a wire-wound type in which a copper wire is wound around a ferrite drum core, and an integrally-molded metallic coil type. Small SMD coils used for the power supply of electronic equipment are called power inductors. Selection Guide for Power Inductors in Consideration of Leakage Flux Magnetic shielding characteristics that lower the leakage flux of power inductors
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |