High-Q three-dimensional microfabricated magnetic-core toroidal inductors for power supplies in package

Thumbnail Image
Le, Hoa Thanh
Nour, Yasser
Pavlovic, Zoran
Ó Mathúna, S. Cian
Knott, Arnold
Jensen, Flemming
Han, Anpan
Kulkarni, Santosh
Ouyang, Ziwei
Journal Title
Journal ISSN
Volume Title
Institute of Electrical and Electronics Engineers (IEEE)
Research Projects
Organizational Units
Journal Issue
The integration of power inductors is a roadblock in realizing highly miniaturized power supply in package (PSiP) and power supply on chip. Inductors in such power systems are used for energy storage and filtering, but they dominate in size and loss. This paper presents a novel three-dimensional in-silicon through-silicon via (TSV) magnetic-core toroidal inductor for PSiP. The magnetic powder based core is embedded into a TSV air-core inductor using a casting method. The unique air-core inductor design with a hollow core and suspended windings enables a complete core filling with microscale magnetic powders. The proposed casting method is simple, scalable, and generic for a wide range of magnetic powders. TSV magnetic-core inductors are fabricated in a compact size of 2.4 mm × 2.4 mm × 0.28 mm with the core content varying from 63 to 88 wt% of soft ferrite NiZn powders. The TSV magnetic-core toroidal inductors are fabricated and electrically characterized. Small-signal measurements show a threefold higher inductance of 112 nH and a 30% higher quality factor of 14.3 at 12.5 MHz for magnetic-core inductors compared with similar TSV air-core inductors. The small-signal measurement results are verified by the modeled results. The total core loss is characterized by large-signal measurements. A suitable inductor is implemented in a 12-MHz buck converter that operates in a zero-voltage-switching mode. The converter achieves a peak efficiency of 71.6% and an output power of 2.4 W while converting 12 to 5 V dc .
Inductor , Magnetic materials , Microfabrication , Power supply in package (PSiP) , Through-silicon via (TSV) , Inductors , Magnetic cores , Through-silicon vias , Toroidal magnetic fields , Powders Soft magnetic materials , Soft magnetic materials , Windings
Le, H. T., Nour, Y., Pavlovic, Z., Mathúna, C. O., Knott, A., Jensen, F., Han, A., Kulkarni, S. and Ouyang, Z. (2019) 'High-QThree-Dimensional Microfabricated Magnetic-Core Toroidal Inductors for Power Supplies in Package', IEEE Transactions on Power Electronics, 34(1), pp. 74-85. doi: 10.1109/TPEL.2018.2847439
© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.