Comparison of Coupled vs. Non-Coupled Microfabricated Inductors in 2W 20MHz Interleaved Buck Converter

Research and industry interest in improving performance, size and cost of DC-DC converters is driving the development of circuit topologies and passive components that are compatible for integration on silicon, particularly magnetic components. In order to quantify the advantages of coupled inductors, this paper presents a design case comparison between coupled vs. non-coupled silicon-integrated microfabricated inductors in a 2 W interleaved DC-DC converter switching at 20 MHz, considering the same circuit specifications and silicon manufacturing capabilities for the silicon-integrated inductors. The study attempts to address the relative advantages and disadvantages of each design in terms of inductor size, loss and circuit transient response, in addition to presenting a selection procedure for a suitable coupling factor that provides flux cancellation over a range of input voltages for 4-phase cyclic cascaded coupled inductor.

[1]  Yan Dong.  Investigation of Multiphase Coupled-Inductor Buck Converters in Point-of-Load Applications , 2009 .

[2]  Krishna Bharath,et al.  Power Delivery Design and Analysis of 14nm Multicore Server CPUs with Integrated Voltage Regulators , 2016, 2016 IEEE 66th Electronic Components and Technology Conference (ECTC).

[3]  Peng Xu,et al.  Investigation of candidate topologies for 12 V VRM , 2002, APEC. Seventeenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.02CH37335).

[4]  Zhigang Dang,et al.  On-chip three-phase coupled power inductor for switching power converters , 2015, 2015 IEEE Applied Power Electronics Conference and Exposition (APEC).

[5]  Santosh Kulkarni,et al.  Analysis of coupled microinductors for power-supplyon-chip applications , 2014, 2014 IEEE Energy Conversion Congress and Exposition (ECCE).

[6]  Gu-Yeon Wei,et al.  A Fully-Integrated 3-Level DC-DC Converter for Nanosecond-Scale DVFS , 2012, IEEE Journal of Solid-State Circuits.

[7]  Fred C. Lee,et al.  Very high frequency integrated voltage regulator for small portable devices , 2016, 2016 IEEE Energy Conversion Congress and Exposition (ECCE).

[8]  Michiel Steyaert,et al.  Scalable Parasitic Charge Redistribution: Design of High-Efficiency Fully Integrated Switched-Capacitor DC–DC Converters , 2016, IEEE Journal of Solid-State Circuits.

[9]  Tobias Schmid,et al.  Magnetically coupled buck converters , 2013, 2013 IEEE Energy Conversion Congress and Exposition.

[10]  Peng Xu,et al.  Performance improvements of interleaving VRMs with coupling inductors , 2001 .

[11]  Charles R. Sullivan,et al.  Accurate prediction of ferrite core loss with nonsinusoidal waveforms using only Steinmetz parameters , 2002, 2002 IEEE Workshop on Computers in Power Electronics, 2002. Proceedings..

[12]  Hou-Ming Chen,et al.  A Two-Phase Fully-Integrated DC–DC Converter With Self-Adaptive DCM Control and GIPD Passive Components , 2015, IEEE Transactions on Power Electronics.

[13]  Fabrice Paillet,et al.  FIVR — Fully integrated voltage regulators on 4th generation Intel® Core™ SoCs , 2014, 2014 IEEE Applied Power Electronics Conference and Exposition - APEC 2014.

[14]  F.C. Lee,et al.  Evaluation of coupled inductor Voltage Regulators , 2008, 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition.

[15]  Johann W. Kolar,et al.  A 10 W On-Chip Switched Capacitor Voltage Regulator With Feedforward Regulation Capability for Granular Microprocessor Power Delivery , 2017, IEEE Transactions on Power Electronics.

[16]  Johann W. Kolar,et al.  Modeling and multi-objective optimization of 2.5D inductor-based Fully Integrated Voltage Regulators for microprocessor applications , 2015, 2015 IEEE 13th Brazilian Power Electronics Conference and 1st Southern Power Electronics Conference (COBEP/SPEC).

[17]  Santosh Kulkarni,et al.  Loss Modeling of Coupled Stripline Microinductors in Power Supply on Chip Applications , 2016, IEEE Transactions on Power Electronics.

[18]  Elad Alon,et al.  Design Techniques for Fully Integrated Switched-Capacitor DC-DC Converters , 2011, IEEE Journal of Solid-State Circuits.

[19]  Ningning Wang,et al.  Design Procedure for Racetrack Microinductors on Silicon in Multi-MHz DC–DC Converters , 2015, IEEE Transactions on Power Electronics.

[20]  Johann W. Kolar,et al.  Modeling and Pareto Optimization of Microfabricated Inductors for Power Supply on Chip , 2013, IEEE Transactions on Power Electronics.

[21]  Jaeha Kim,et al.  A 500-MHz, 0.76-W/mm Power Density and 76.2% Power Efficiency, Fully Integrated Digital Buck Converter in 65-nm CMOS , 2016, IEEE Transactions on Industry Applications.

[22]  Srinivasan Govindan,et al.  Silicon-package power delivery co-simulation with Fully Integrated Voltage Regulators on microprocessors , 2014, 2014 IEEE Electrical Design of Advanced Packaging & Systems Symposium (EDAPS).