High density low profile coupled inductor design for integrated Point-of-Load converter

Low profile integrated Point-of-Load (POL) converter is today's industry trend for portable electronic applications. Magnetics is the major challenge and bottleneck for achieving low profile high power density integrated POL. So, how to design a low profile magnetic becomes one of the key technologies for integrated POL. Inverse coupling is one of the possible methods to reduce inductor size due to the dc flux cancelling effect. Several integrated low profile coupled inductor structures with different flux patterns (vertical flux and lateral flux) are proposed in this paper based on low temperature co-fired ceramics (LTCC) technology. This paper also reveals that the lateral flux coupled inductor structure can have higher inductance density than vertical flux structure. Two LTCC coupled inductor prototypes are designed and fabricated to verify the theoretical analysis. A 1.5MHz, 5V to 1.2V, 3D integrated buck converter with LTCC coupled inductor substrate is also fabricated. The power density of this integrated converter is as high as 700W/in3.

[1]  Fred C. Lee,et al.  High Inductance Density Low-Profile Inductor Structure for Integrated Point-of-Load Converter , 2009, 2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition.

[2]  Charles R. Sullivan,et al.  Coupled-inductor design optimization for fast-response low-voltage DC-DC converters , 2002, APEC. Seventeenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.02CH37335).

[3]  Miguel J. Prieto,et al.  Design and analysis of thick-film integrated inductors for power converters , 2002 .

[4]  F. Lee,et al.  A Class of Ceramic-Based Chip Inductors for Hybrid Integration in Power Supplies , 2008, IEEE Transactions on Power Electronics.

[5]  T. Mikura,et al.  New substrate for micro DC-DC converter , 2006, 56th Electronic Components and Technology Conference 2006.

[6]  Pit-Leong Wong,et al.  Performance Improvements of Multi-Channel Interleaving Voltage Regulator Modules with Integrated Coupling Inductors , 2001 .

[7]  F.C. Lee,et al.  System design of a 3D integrated non-isolated Point Of Load converter , 2008, 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition.

[8]  Peng Xu,et al.  Investigating coupling inductors in the interleaving QSW VRM , 2000, APEC 2000. Fifteenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.00CH37058).

[9]  Fred C. Lee,et al.  Novel Coupled-Inductor Multi-phase VRs , 2007, APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition.

[10]  J.A. Ferreira,et al.  Design method and material technologies for passives in printed circuit Board Embedded circuits , 2005, IEEE Transactions on Power Electronics.

[11]  H. Reichl,et al.  Low profile power inductors based on ferromagnetic LTCC technology , 2006, 56th Electronic Components and Technology Conference 2006.