Integrating magnetics for on-chip power: Challenges and opportunities

Sullivan, Charles R.

doi:10.1109/cicc.2009.5280823

Cited by 51 publications

(30 citation statements)

References 56 publications

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“…This composite signal has been tested for two different waveforms' frequencies: on the left 100 kHz and on the right 500 kHz. From the measurement of v and i, H and B have been calculated applying (1) and (2). The hysteresis loops related to the different waveforms are highlighted with different colors.…”

Section: Test Signal With Multiple Waveforms and DC Biasmentioning

confidence: 99%

“…Both solutions are currently evaluated in the above mentioned range of frequencies, while it seems that magnetic-core still presents a higher inductance density with respect to aircore ones. [2][3][4][5] For this reason, it is important to evaluate new magnetic materials capable to work at high frequency and with technological properties compatible with miniaturization.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Automated setup for magnetic hysteresis characterization based on a voltage controlled current source with 500 kHz full power bandwidth and 10 A peak-to-peak current

Calabrese

Capineri

Granato

et al. 2015

Review of Scientific Instruments

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This paper describes the design of a system for the characterization of magnetic hysteresis behavior in soft ferrite magnetic cores. The proposed setup can test magnetic materials exciting them with controlled arbitrary magnetic field waveforms, including the capability of providing a DC bias, in a frequency bandwidth up to 500 kHz, with voltages up to 32 V peak-to-peak, and currents up to 10 A peak-to-peak. In order to have an accurate control of the magnetic field waveform, the system is based on a voltage controlled current source. The electronic design is described focusing on closed loop feedback stabilization and passive components choice. The system has real-time hysteretic loop acquisition and visualization. The comparisons between measured hysteresis loops of sample magnetic materials and datasheet available ones are shown. Results showing frequency and thermal behavior of the hysteresis of a test sample prove the system capabilities. Moreover, the B-H loops obtained with a multiple waveforms excitation signal, including DC bias, are reported. The proposal is a low-cost and replicable solution for hysteresis characterization of magnetic materials used in power electronics.

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Section: Test Signal With Multiple Waveforms and DC Biasmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Automated setup for magnetic hysteresis characterization based on a voltage controlled current source with 500 kHz full power bandwidth and 10 A peak-to-peak current

Calabrese

Capineri

Granato

et al. 2015

Review of Scientific Instruments

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show abstract

“…Magnetic components with high efficiency, high power density and low profile are needed for integration in power-supplyin-package and/or power-supply-on-chip [3]- [7]. Toroidal inductors have attractive geometries compared to solenoids and planar spirals, as they have little external field, which can cause electromagnetic interference and induce eddy-current loss in nearby conductors [8]- [11].…”

Section: Introductionmentioning

confidence: 99%

A toroidal power inductor using radial-anisotropy thin-film magnetic material based on a hybrid fabrication process

Qiu

Harburg

Sullivan

2013

2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC)

Self Cite

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This paper presents improvements for the design and fabrication of high-frequency toroidal power inductors with and without radial-anisotropy thin-film magnetic material. An improved winding resistance model for toroids is developed considering an angle factor for actual winding shape, the effect of spacing between turns and loss associated with exterior current in the circumferential direction. A hybrid process for fabricating low-profile magnetic-core toroids is presented. The process uses standard flex printed circuit board (PCB) technology for the top and bottom winding layers with vias electroplated after sandwiching the magnetic core between the two winding layers. Thin-film magnetic material (Co-Zr-O) is deposited in the presence of a radial magnetic field, which induces radial anisotropy in the toroidal core. Small-signal measurements show that the toroidal core has a relative permeability over 40 at frequencies up to several hundred megahertz, and very high quality factor in the frequency range below 100 MHz. Aircore and magnetic-core toroidal inductors using this hybrid fabrication process were built and tested at small-signal levels. Magnetic-core toroids showed a higher inductance and quality factor than air-core toroids at frequencies below 100 MHz. This winding loss model and fabrication process can be applied to both air-core and magnetic-core toroidal inductors.

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“…The second category is embedded inductors, in which the inductors are embedded inside the Si substrate and utilize the unused substrate volume. Consequently, the inductor height above the substrate surface can be lowered, which is an advantage for integrated circuit implementation 14 . Si-embedded inductors are also an attractive solution for the advanced packaging of ultra-compact power supplies with the passive interposer 24 .…”

Section: Introductionmentioning

confidence: 99%

“…In the VHF range, inductors with an air core or non-magnetic core are preferred, as suitable magnetic materials working at these frequencies are limited and the core implementation is very challenging 13 . For example, at 50 MHz, NiZn and CoNiZn have low magnetic saturation fluxes and cause detrimental core heating in high-flux power electronics applications 14 . In addition, VHF converters require inductance values of 10 s of nH, which is in the inductance range of air-core inductors, thereby lending themselves to a promising solution 15 .…”

Section: Introductionmentioning

confidence: 99%

Fabrication of 3D air-core MEMS inductors for very-high-frequency power conversions

Thanh

Mizushima²,

Nour

et al. 2018

Microsyst Nanoeng

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We report a fabrication technology for 3D air-core inductors for small footprint and very-high-frequency power conversions. Our process is scalable and highly generic for fabricating inductors with a wide range of geometries and core shapes. We demonstrate spiral, solenoid, and toroidal inductors, a toroidal transformer and inductor with advanced geometries that cannot be produced by wire winding technology. The inductors are embedded in a silicon substrate and consist of through-silicon vias and suspended windings. The inductors fabricated with 20 and 25 turns and 280-350 μm heights on 4-16 mm 2 footprints have an inductance from 34.2 to 44.6 nH and a quality factor from 10 to 13 at frequencies ranging from 30 to 72 MHz. The air-core inductors show threefold lower parasitic capacitance and up to a 140% higher-quality factor and a 230% higher-operation frequency than silicon-core inductors. A 33 MHz boost converter mounted with an air-core toroidal inductor achieves an efficiency of 68.2%, which is better than converters mounted with a Si-core inductor (64.1%). Our inductors show good thermal cycling stability, and they are mechanically stable after vibration and 2-m-drop tests.

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Integrating magnetics for on-chip power: Challenges and opportunities

Cited by 51 publications

References 56 publications

Automated setup for magnetic hysteresis characterization based on a voltage controlled current source with 500 kHz full power bandwidth and 10 A peak-to-peak current

Automated setup for magnetic hysteresis characterization based on a voltage controlled current source with 500 kHz full power bandwidth and 10 A peak-to-peak current

A toroidal power inductor using radial-anisotropy thin-film magnetic material based on a hybrid fabrication process

Fabrication of 3D air-core MEMS inductors for very-high-frequency power conversions

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