ITG Electronics, a leading manufacturer of inductors and transformers in business since 1963, now offers a range common footprints as well as custom flat wire inductors for high power density and high frequency switching.
As the name suggests, flat wire inductors utilize a flattened, rectangular cross section, copper wire instead of a traditional, circular cross section, wire. The advantage of this change is more surface area. At high frequencies, the current penetrates and utilizes less and less of the volume of the copper wire. This is called the skin effect, because at high frequencies only the ‘skin’ of the wire is utilized. A flat wire maximizes usable wire at high frequencies due to its increased surface area.
This advantage has rippling effects through other aspects of the inductors performance as well. In general, the higher the frequency, the lower the permissible current through a specific wire, again, due to the skin effect, because the current is not utilizing all of the available wire. This means part of the wire is wasted, driving up resistance and heat in addition to lowering the current rating. With a flat wire inductor all these effects are stifled as the current is able to use the whole wire more efficiently.
Flat wire inductors not only use current more efficiently, they use space more efficiently. A flat wire can easily exceed window fill and winding density of its round wire counterparts. The result is a very high density part that takes up less space, uses less energy, and can operate at a higher frequency.