A horizontal-winding multi-permeability distributed air-gap inductor

Distributed air-gap inductors have the advantage of reducing winding loss in high switching frequency DC/DC converters. However, they also have the disadvantage of uneven distribution of flux density, which inevitably leads to the incomplete utilization of magnetic material. This paper proposes a horizontal-winding multi-permeability distributed air-gap inductor structure to increase inductance without the increase of inductor volume. To evaluate the proposed method, a two-permeability inductor together with a single permeability inductor is fabricated. The measured results show the two-permeability inductor has higher inductance than the single-permeability one, especially at light load. Both inductors are tested in a 12V input, 1.6V output DC/DC converter to show their performance. The results show the two-permeability inductor could further improve light load efficiency of high frequency DC/DC converters.