Ni-Zn Ferrite Screen Printed Power Inductors for Compact DC-DC Power Converter Applications

In this paper, PCB embedded power inductors have been designed, fabricated, and characterized for low power compact DC-DC converter applications by using screen-printing and low temperature processing technologies. These proposed power inductors were comprised of screen-printed Ni-Zn soft ferrite composite cores and two layer vertically stacked spiral type coils. The double stacked spiral coil geometry was applied to reduce the size and to increase the inductance value of the proposed power inductor. The fabricated power inductor with double stacked circular type coils and 9 windings exhibited an inductance of 0.81 muH, a quality factor of 45 at 10 MHz, and a DC rated current of 470 mA. Its size (4.5 mm times 4.5 mm times 0.5 mm (height)) was much smaller than the previously reported devices. The circular type power inductors had smaller size and better performance characteristics than the rectangular type ones.