Review of Integrated Magnetics for Power Supply on Chip (PwrSoC)

This paper reviews the current state of power supply technology platforms and highlights future trends and challenges toward realizing fully monolithic power converters. This paper presents a detailed survey of relevant power converter technologies, namely power supply in package and power supply on chip (PwrSoC). The performance of different power converter solutions reported in the literature is benchmarked against existing commercial products. This paper presents a detailed review of integrated magnetics technologies, primarily microinductors, a key component in realizing a monolithic power converter. A detailed review and comparison of different microinductor structures and the magnetic materials used as inductor cores is presented. The deposition techniques for integrating the magnetic materials in the microinductor structures are discussed. This paper proposes the use of two performance metrics or figures of merit in order to compare the dc and ac performance of individual microinductor structures. Finally, the authors discuss future trends, key challenges, and potential solutions in the realization of the “holy grail” of monolithically integrated power supplies (PwrSoC).

[1]  M Wens,et al.  A Fully Integrated CMOS 800-mW Four-Phase Semiconstant ON/OFF-Time Step-Down Converter , 2011, IEEE Transactions on Power Electronics.

[2]  Kiyohito Yamasawa,et al.  High frequency soft magnetic properties of nanocrystalline Fe-(Co)-Hf-O films with high electrical resistivity and their application to micro DC-DC converter , 1997 .

[3]  M. Allen,et al.  Ultralow-profile micromachined power inductors with highly laminated Ni/Fe cores: application to low-megahertz DC-DC converters , 2003 .

[4]  J. F. Dickson,et al.  On-chip high-voltage generation in MNOS integrated circuits using an improved voltage multiplier technique , 1976 .

[5]  S. Borkar,et al.  Review of On-Chip Inductor Structures With Magnetic Films , 2009, IEEE Transactions on Magnetics.

[6]  Saibal Roy,et al.  An ac susceptibility study in capped Ni/Ni(OH)2 core–shell nanoassemblies: dual peak observations , 2011 .

[7]  K. Yamasawa,et al.  Application Of Nanocrystalline Fe- Or (CoFe)-Hf-O Magnetic Films With High Electrical Resistivity To A Micro DC-DC Converter , 1997, 1997 IEEE International Magnetics Conference (INTERMAG'97).

[8]  Fabrice Paillet,et al.  Integrated On-Chip Inductors Using Magnetic Materials , 2011 .

[9]  Saibal Roy,et al.  Magnetic properties of oxide-coated iron nanoparticles synthesized by electrodeposition , 2000 .

[10]  M. Allen,et al.  Batch-fabricated microinductors with electroplated magnetically anisotropic and laminated alloy cores , 1999 .

[11]  Charles R. Sullivan,et al.  Evaporatively deposited Co-MgF/sub 2/ granular materials for thin-film inductors , 2000 .

[12]  Ravi Karadi,et al.  A 65-nm-CMOS 100-MHz 87%-efficient DC-DC down converter based on dual-die system-in-package integration , 2009, 2009 IEEE Energy Conversion Congress and Exposition.

[13]  S. Narendra,et al.  A 233-MHz 80%-87% efficient four-phase DC-DC converter utilizing air-core inductors on package , 2005, IEEE Journal of Solid-State Circuits.

[14]  Y. Mano,et al.  Embedded inductor using Ni-Zn ferrite film in polymer substrate , 2005, INTERMAG Asia 2005. Digests of the IEEE International Magnetics Conference, 2005..

[15]  Anantha P. Chandrakasan,et al.  A 0.16mm2 completely on-chip switched-capacitor DC-DC converter using digital capacitance modulation for LDO replacement in 45nm CMOS , 2010, 2010 IEEE International Solid-State Circuits Conference - (ISSCC).

[16]  M. Allen,et al.  A new toroidal-meander type integrated inductor with a multilevel meander magnetic core , 1994 .

[17]  D. O'Sullivan,et al.  Microfabricated inductors for 20 MHz Dc-Dc converters , 2008, 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition.

[18]  Tetsuo Inoue,et al.  The effect of magnetic film structure on the inductance of a planar inductor , 1998 .

[19]  Yongsoo Oh,et al.  Planar inductor with ferrite layers for DC-DC converter , 2005, The 13th International Conference on Solid-State Sensors, Actuators and Microsystems, 2005. Digest of Technical Papers. TRANSDUCERS '05..

[20]  Hoi-Jun Yoo,et al.  A regulated charge pump with small ripple voltage and fast start-up , 2006 .

[21]  Dragan Maksimovic,et al.  Switched-capacitor DC-DC converters for low-power on-chip applications , 1999, 30th Annual IEEE Power Electronics Specialists Conference. Record. (Cat. No.99CH36321).

[22]  Mark G. Allen,et al.  A fully integrated planar toroidal inductor with a micromachined nickel-iron magnetic bar , 1994 .

[23]  Michael D. Seeman,et al.  A 32nm fully integrated reconfigurable switched-capacitor DC-DC converter delivering 0.55W/mm2 at 81% efficiency , 2010, 2010 IEEE International Solid-State Circuits Conference - (ISSCC).

[24]  P. Hazucha,et al.  A 100MHz Eight-Phase Buck Converter Delivering 12A in 25mm2 Using Air-Core Inductors , 2007, APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition.

[25]  M. Allen,et al.  A sacrificial layer approach to highly laminated magnetic cores , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).

[26]  C. Sullivan,et al.  Comparison of magnetic materials for V-groove inductors in optimized high-frequency DC-DC converters , 2004, IEEE Transactions on Magnetics.

[27]  Tetsuya Osaka,et al.  A soft magnetic CoNiFe film with high saturation magnetic flux density and low coercivity , 1998, Nature.

[28]  L. Colalongo,et al.  A new integrated charge pump architecture using dynamic biasing of pass transistors , 2005, Proceedings of the 31st European Solid-State Circuits Conference, 2005. ESSCIRC 2005..

[29]  Erik J. Brandon,et al.  AC and DC current dependance of on-chip conductors , 2000 .

[30]  K.D.T. Ngo,et al.  Technology roadmap for high frequency integrated DC-DC converter , 2009, 2009 IEEE 6th International Power Electronics and Motion Control Conference.

[31]  Tetsuya Osaka,et al.  Electrodeposition of highly functional thin films for magnetic recording devices of the next century , 2000 .

[32]  Saibal Roy,et al.  Interface controlled electrical and magnetic properties in Fe–Fe3O4–silica gel nanocomposites , 2002 .

[33]  Y. Savaria,et al.  High voltage charge pump using standard CMOS technology , 2004, The 2nd Annual IEEE Northeast Workshop on Circuits and Systems, 2004. NEWCAS 2004..

[34]  G. Herzer,et al.  Nanocrystalline soft magnetic materials , 1993 .

[35]  W.G. Dunford,et al.  A Fully Integrated 660 MHz Low-Swing Energy-Recycling DC–DC Converter , 2009, IEEE Transactions on Power Electronics.

[36]  M.A. Nekoui,et al.  Analyzing optimization of fluxgate sensor , 2008, 2008 International Conference on Electronic Design.

[37]  Radivoje Popovic,et al.  CMOS planar 2D micro-fluxgate sensor , 2000 .

[38]  Vincent W Ng,et al.  Minimum PCB footprint point-of-load DC-DC converter realized with Switched-Capacitor architecture , 2009, 2009 IEEE Energy Conversion Congress and Exposition.

[39]  M. Yamaguchi,et al.  All-in-one package ultracompact micropower module using thin-film inductor , 2004, IEEE transactions on magnetics.

[40]  Y. Miura,et al.  A planar inductor using Mn-Zn ferrite/polyimide composite thick film for low-Voltage and large-current DC-DC converter , 2005, IEEE Transactions on Magnetics.

[41]  Chang-Min Park,et al.  Design and Fabrication of On-Chip Coupled Inductors Integrated With Magnetic Material for Voltage Regulators , 2011, IEEE Transactions on Magnetics.

[42]  Babak Ziaie,et al.  Fabrication and modeling of silicon-embedded high-Q inductors , 2005 .

[43]  G. Herzer,et al.  Grain size dependence of coercivity and permeability in nanocrystalline ferromagnets , 1990, International Conference on Magnetics.

[44]  P. Ancey,et al.  Low Resistance Integrated Toroidal Inductors for Power Management , 2006, INTERMAG 2006 - IEEE International Magnetics Conference.

[45]  Charles R. Sullivan,et al.  Design of microfabricated transformers and inductors for high-frequency power conversion , 1996 .

[46]  T. O'Donnell,et al.  Micro-inductors integrated on silicon for power supply on chip , 2007 .

[47]  Yong Zhou,et al.  Fabrication of ultralow-profile micromachined inductor with magnetic core material , 2005 .

[48]  M. Steyaert,et al.  A 1.65W fully integrated 90nm Bulk CMOS Intrinsic Charge Recycling capacitive DC-DC converter: Design & techniques for high power density , 2011, 2011 IEEE Energy Conversion Congress and Exposition.

[49]  K. Nishijima,et al.  5 MHz switching micro DC-DC converter using planar inductor , 1996, Proceedings of Intelec'96 - International Telecommunications Energy Conference.

[50]  M. Dudek,et al.  Chosen electrical and stability properties of surface and embedded planar PCB inductors , 2008, 2008 31st International Spring Seminar on Electronics Technology.

[51]  T. O'Donnell,et al.  Size and Performance Tradeoffs in Micro-Inductors for High Frequency DC-DC Conversion , 2009, IEEE Transactions on Magnetics.

[52]  Seiji Mitani,et al.  Co(N, O)-based granular thin films and their soft magnetic properties , 1995 .

[53]  T. O'Donnell,et al.  Magnetic-Core and Air-Core Inductors on Silicon: A Performance Comparison up to 100 MHz , 2011, IEEE Transactions on Magnetics.

[54]  G. Patounakis,et al.  A fully integrated on-chip DC-DC conversion and power management system , 2004, IEEE Journal of Solid-State Circuits.

[55]  H. Nishio,et al.  High efficiency DC-DC converter chip size module with integrated soft ferrite , 2003, Digest of INTERMAG 2003. International Magnetics Conference (Cat. No.03CH37401).

[56]  D. Kosy,et al.  The write field of a magnetic-film recording head , 1969 .

[57]  T. O'Donnell,et al.  Thin-Film-Integrated Power Inductor on Si and Its Performance in an 8-MHz Buck Converter , 2008, IEEE Transactions on Magnetics.

[58]  S. Sugahara,et al.  Micro DC/DC converter that integrates planar inductor on power IC , 2000 .

[59]  Xun Gong,et al.  On-Chip Bondwire Magnetics with Ferrite-Epoxy Glob Coating for Power Systems on Chip , 2008 .

[60]  Y. Katayama,et al.  High-power-density MHz-switching monolithic DC-DC converter with thin-film inductor , 2000, 2000 IEEE 31st Annual Power Electronics Specialists Conference. Conference Proceedings (Cat. No.00CH37018).

[61]  Rongxiang Wu,et al.  A Novel Silicon-Embedded Coreless Inductor for High-Frequency Power Management Applications , 2011, IEEE Electron Device Letters.

[62]  K. Venkatachalam,et al.  Measured electrical performance of V-groove inductors for microprocessor power delivery , 2003, Digest of INTERMAG 2003. International Magnetics Conference (Cat. No.03CH37401).

[63]  Hiroshi Tomita,et al.  Hetero-amorphous Fe-Co-B-C soft magnetic thin films with uniaxial magnetic anisotropy and large magnetostriction , 1996 .

[64]  R. Hida,et al.  Low-Resistance Integrated Toroidal Inductor for Power Management , 2006, IEEE Transactions on Magnetics.

[65]  Yuqin Sun,et al.  Microfabricated V-Groove Power Inductors for High-Current Low-Voltage Fast-Transient DC-DC Converters , 2005, 2005 IEEE 36th Power Electronics Specialists Conference.

[66]  Seth R. Sanders,et al.  In-board magnetics processes , 1999, 30th Annual IEEE Power Electronics Specialists Conference. Record. (Cat. No.99CH36321).

[67]  Zhiliang Hong,et al.  Improved on-chip components for integrated DC-DC converters in 0.13 µm CMOS , 2009, 2009 Proceedings of ESSCIRC.

[68]  E. Alarcon,et al.  Monolithic integration of a 3-level DCM-operated low-floating-capacitor buck converter for DC-DC step-down donversion in standard CMOS , 2008, 2008 IEEE Power Electronics Specialists Conference.

[69]  Dok Won Lee,et al.  Fabrication and Analysis of High-Performance Integrated Solenoid Inductor With Magnetic Core , 2008, IEEE Transactions on Magnetics.

[70]  Jian Lu,et al.  On-Chip Bondwire Inductor with Ferrite-Epoxy Coating: A Cost-Effective Approach to Realize Power Systems on Chip , 2007, 2007 IEEE Power Electronics Specialists Conference.

[71]  H. Kawaguchi,et al.  Stacked-chip Implementation of On-Chip Buck Converter for Power-Aware Distributed Power Supply Systems , 2006, 2006 IEEE Asian Solid-State Circuits Conference.

[72]  Jian Lu,et al.  Integration of a Monolithic Buck Converter Power IC and Bondwire Inductors With Ferrite Epoxy Glob Cores , 2011, IEEE Transactions on Power Electronics.

[73]  S. Han,et al.  A megahertz switching DC/DC converter using FeBN thin film inductor , 2002 .

[74]  F. Cros,et al.  Planar spiral inductors with multilayer micrometer-scale laminated cores for compact-packaging power converter applications , 2004, IEEE Transactions on Magnetics.

[75]  Dongsheng Ma,et al.  A monolithic step-down SC power converter with frequency-programmable subthreshold z-domain DPWM control for ultra-low power microsystems , 2008, ESSCIRC 2008 - 34th European Solid-State Circuits Conference.

[76]  S.C.O. Mathuna,et al.  PCB integrated inductors for low power DC/DC converter , 2003 .

[77]  M. Kaiser,et al.  Ultrahigh Capacitance Density for Multiple ALD-Grown MIM Capacitor Stacks in 3-D Silicon , 2008, IEEE Electron Device Letters.

[78]  Mark G. Allen,et al.  Development of magnetic materials and processing techniques applicable to integrated micromagnetic devices , 1998 .

[79]  Terence O'Donnell,et al.  Electrical performance of microtransformers for DC-DC converter applications , 2002 .

[80]  E. Brandon,et al.  Fabrication and characterization of microinductors for distributed power converters , 2003 .

[81]  Charles R. Sullivan,et al.  Microfabrication of transformers and inductors for high frequency power conversion , 1993, Proceedings of IEEE Power Electronics Specialist Conference - PESC '93.

[82]  Charles R. Sullivan,et al.  Microfabricated V-groove power inductors using multilayer Co-Zr-O thin films for very-high-frequency DC-DC converters , 2011, 2011 IEEE Energy Conversion Congress and Exposition.

[83]  S.R. Sanders,et al.  Design, manufacture and application of in-board magnetic devices , 2004, The 4th International Power Electronics and Motion Control Conference, 2004. IPEMC 2004..

[84]  P.L. Chapman,et al.  Design of Low Power Monolithic DC-DC Buck Converter with Integrated Inductor , 2005, 2005 IEEE 36th Power Electronics Specialists Conference.

[85]  S.C. O'Mathuna,et al.  Analysis of Microinductor Performance in a 20-100 MHz DC/DC Converter , 2009, IEEE Transactions on Power Electronics.

[86]  R. Harjani,et al.  A High-Efficiency DC–DC Converter Using 2 nH Integrated Inductors , 2008, IEEE Journal of Solid-State Circuits.

[87]  David Flynn,et al.  A design study of microscale magnetic components for operation in the MHz frequency range , 2006 .

[88]  A. Tipek,et al.  Excitation and temperature stability of PCB fluxgate sensor , 2005, IEEE Sensors Journal.

[89]  Erik J. Brandon,et al.  Microinductors for Spacecraft Power Electronics , 2000 .

[90]  T. O'Donnell,et al.  Microfabricated coupled inductors for DC-DC converters for microprocessor power delivery , 2004, 2004 IEEE 35th Annual Power Electronics Specialists Conference (IEEE Cat. No.04CH37551).

[91]  Yuqin Sun,et al.  30-MHz Power Inductor Using Nano-Granular Magnetic Material , 2007, 2007 IEEE Power Electronics Specialists Conference.

[92]  M. Mino,et al.  A compact buck-converter using a thin-film inductor , 1996, Proceedings of Applied Power Electronics Conference. APEC '96.

[93]  M. Pasotti,et al.  Power efficient charge pump in deep submicron standard CMOS technology , 2003, Proceedings of the 27th European Solid-State Circuits Conference.

[94]  Lubomyr T. Romankiw,et al.  Batch-fabricated thin-film magnetic recording heads , 1970 .

[95]  Hiroshi Tomita,et al.  A magnetic thin film inductor and its application to a MHz switching dc-dc converter , 1994 .

[96]  Tetsuo Inoue,et al.  Planar inductor with ferrite layers for DC-DC converter , 2003 .

[97]  Saibal Roy,et al.  Shape-independent permeability model for uniaxially-anisotropic ferromagnetic thin films , 2010 .

[98]  Jian Lu,et al.  Modeling, Design, and Characterization of Multiturn Bondwire Inductors With Ferrite Epoxy Glob Cores for Power Supply System-on-Chip or System-in-Package Applications , 2010, IEEE Transactions on Power Electronics.

[99]  M. Brunet,et al.  High-frequency micro-machined power inductors , 2005 .

[100]  Khai D. T. Ngo,et al.  A novel integrated power inductor in silicon substrate for ultra-compact power supplies , 2010, 2010 Twenty-Fifth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[101]  Charles R. Sullivan,et al.  Integrating magnetics for on-chip power: Challenges and opportunities , 2009, 2009 IEEE Custom Integrated Circuits Conference.

[102]  C. Sullivan,et al.  High-frequency resistivity of soft magnetic granular films , 2005, IEEE Transactions on Magnetics.

[103]  Michiel Steyaert,et al.  A 82% efficiency 0.5% ripple 16-phase fully integrated capacitive voltage doubler , 2009, 2009 Symposium on VLSI Circuits.

[104]  M. Allen,et al.  Integrated electroplated micromachined magnetic devices using low temperature fabrication processes , 2000 .

[105]  Mark G. Allen,et al.  Micromachined planar inductors on silicon wafers for MEMS applications , 1998, IEEE Trans. Ind. Electron..

[106]  Saibal Roy,et al.  Magnetic properties of Ni nanoparticles on microporous silica spheres , 2010 .

[107]  Cian O Mathuna,et al.  Integrated magnetics on silicon for power supply in package (PSiP) and power supply on chip (PwrSoC) , 2010, 3rd Electronics System Integration Technology Conference ESTC.

[108]  Baoxing Chen,et al.  Isolation in Digital Power Supplies Using Micro-Transformers , 2009, 2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition.

[109]  Charles R. Sullivan,et al.  Perpendicular anisotropy in granular Co-Zr-O films , 2005 .