Array Of Inductors Research Articles

A Discrete Coupled Multiphase Interleaved LLC Converter With Symmetrical Components Analysis

This paper proposes a coupling structure and a generalized analysis approach for multi-phase interleaved LLC converters that applies to all odd phases that can simultaneously improve the current balancing in all interleaved phases. Firstly, a discrete coupled inductor array (DCIArray) structure is proposed, and its magnetic circuit model is analyzed in detail; then, the generalized symmetrical component theory is introduced to decouple the inductance matrix to the sequence impedance, with expansion to all odd-phase LLC converters, and then the sequence impedance, coupling coefficient, components tolerance impacts, and extended voltage gain with control architecture are discussed under the corresponding models; Finally, the recommended design for three-phase and five-phase DCIArray was discussed. Experiments based on both three-phase and five-phase prototypes have proved that the proposed scheme has excellent current sharing in almost all frequency ranges.

High Inductance Density Glass Embedded Inductors for 3-D Integration

Compared with silicon-based inductors, the inductors with through glass via (TGV) technology have significantly improved in quality ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q)$</tex-math> </inline-formula> factor. On the basis of TGV technology, a new type of 3-D embedded inductor is designed for the application scenarios with high inductance density. Through this research, a new preparation process is proposed to reduce the diameter of glass porous. On the basis of fully metallizing the glass porous, larger inductance density is achieved. The fabrication procedure requires grooving inside the glass substrate. In order to ensure the normal metal wiring on the surface, the cavity is filled with organic matter. Finally, the high-density, small-porous inductor array achieves an inductance density of 67.9 nH/mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{2}$</tex-math> </inline-formula> , which is three times higher than the previous glass inductance density. At the same time, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$</tex-math> </inline-formula> factor is 49 and the self-resonance frequency (SRF) is 5.6 GHz.

Optimization of Ground-via Patterns for via Transitions by Minimizing Loop Inductance

Via is a commonly-used interconnect structure for vertically connecting signal traces or power or ground planes in packages and boards. As the speed of data transfer increases, the electrical properties of via structure becomes more and more important for getting better signal quality. Modeling a via structure typically involves complex computation. In this article, authors use partial element method to model the structure as coupled inductor array. It firstly proves that the loop inductance of a single-ended via transition is minimized through perturbation analysis. On the other hand, the differential-mode loop inductance of a via pair surrounded by 2, 4, 6, and 8 ground vias respectively is also derived. The full-wave simulation results all show good agreement with the ones predicted by formulae. Thus, with these formula, the optimization of ground via placement could be quickly found.

Self-Powered Single-Inductor Rectifier-Less SSHI Array Interface With the MPPT Technique for Piezoelectric Energy Harvesting

Piezoelectric energy harvester (PEH) arrays are practical solutions to the low and unreliable power output of a single PEH. However, most PEH circuits are developed for addressing the one-channel ac input from a single PEH. In this article, an extensible rectifier-less synchronized switch harvesting on inductor (ReL-SSHI) array interface with the maximal power point tracking (MPPT) function to manage the multiple ac inputs from the PEH arrays is designed. The ac–dc conversion is performed by the ReL-SSHI topology with passive peak switches featured with self-powered characteristic and fast cold-start. Only one shared inductor is employed, greatly reducing the circuit volume and cost. The MPPT module for each channel is implemented by a simple envelope detector and an ultra-low power hysteresis controller and achieves continuous energy extraction by adapting the fractional normal-operation voltage method. A developed discrete array interface able to handle three PEHs effectively executes the MPPT for each channel with the uphill and downhill response speeds of 2.0 and 7.1 V/s, and a maximal MPPT efficiency of 97.1%. This circuit boosts the power output by 485% compared with that by the traditional full-bridge rectifier, around 33% higher than that from existing synchronous electric charge extraction array interfaces.

A Self-Powered P-SSHI Array Interface for Piezoelectric Energy Harvesters With Arbitrary Phase Difference

Piezoelectric energy harvester (PEH) arrays are promising in many application scenarios. However, few interface circuits have been developed to manage the multiple ac inputs from PEHs. This article proposes an extensible parallel synchronized switch harvesting on inductor array interface scheme to realize a multiinput conversion from PEH arrays. We develop a split-inductor-capacitor topology that can extract electrical energy from multiple PEHs. The proposed circuit topology effectively handles the inductor access conflict in the cases of PEHs with close, identical, and opposite vibration phases, insensitive to ac input phase changes. For demonstrating the capability of dealing with multiple ac inputs from PEHs and the enhancement effect on power output, we construct and test a self-powered three-channel array circuit with the passive peak detection function. Excited by sinusoidal vibrations, our circuit effectively avoids the energy return and efficiently achieves the power combination of the three PEHs. Compared with the classic full-bridge circuit, the proposed circuit helps increase the power output by 4.8 times. Also, to show the universality of the circuit, the circuit's operation under various excitations istested and analyzed.

A miniaturised mono‐cone antenna with top plate and composite lumped loading

A wideband mono-cone antenna is proposed. Evolution from a top-loaded mono-cone, the top plate is etched by two rings and loaded by an array of resistors and inductors. This design improves impedance matching properties in the low frequency range while maintaining a compact size. An equivalent circuit modal is built for assisting the antenna design. A prototype is fabricated and measured for verification. The antenna operates in the frequency band of 118–1100 MHz with |S11|≤-10 dB and the fluctuation of omni-directional radiation pattern ≤ 2.5 dB. The occupied area of the antenna is 0.24 λL × 0.24 λL × 0.06 λL, which is attractive for use on aircraft.

A Low-Frequency Eddy Current Probe Based on Miniature Fluxgate Array for Defect Evaluation in Steel Components

Detecting defects in high-permeability steel components can be challenging when using the eddy current technique. This is due to the strong magnetization signal that is simultaneously generated along with the eddy current signal. To minimize the regions of the induced eddy current and its detection, an eddy current probe based on an array of miniature fluxgate sensors (DRV425, Texas Instrument, USA) and axial inductors was proposed and fabricated in the study. The fluxgate sensors were arranged in two layers, and the sensors were sandwiched between two layers of inductors. The output signals from the fluxgate array were sampled to obtain a differential signal of the eddy current intensity and direction. A phase-sensitive detection technique was implemented to isolate the strong magnetization signal from the detected eddy current signal and utilized to characterize artificial slits with varying depths. The developed probe successfully characterized both the vertically and horizontally oriented slits with depths from 2 to 10 mm on a 12 mm thick mild steel plate. A better sensitivity was notable in the evaluation of the vertical slits where the vertical slits would increase the eddy current intensity in contrast to the horizontal slits around the slits. It was shown that the eddy current’s distribution map obtained from the developed probe could be used to reveal the physical dimension of the slit.

Two‐/three‐coil hybrid topology and coil design for WPT system charging electric bicycles

Wireless power transfer (WPT) for charging electric bicycles (EBs) can save people from tiresome plugging actions and avoid electrical shock hazards, especially in adverse weather. This study proposed a two-/three-coil hybrid topology to achieve constant current (CC) and constant voltage (CV) for charging EBs, simplifying control schemes. The system realises CC output with two-coil topology and operates in CV mode with three-coil topology by turning on a switch. Besides, an inductor array is used to compensate reactive power in CV mode when massive EBs are charged by one high-frequency inverter (HFI). The secondary side of the proposed topology is compact, and the number of components and HFI can be reduced. A coil design process based on double-D-type for the three-coil system is given, with the constraint of mutual inductances among three coils and limited size. To demonstrate the validity of the proposed methods, an experimental setup is built, and the performance of the two-/three-coil hybrid system indicates that the fluctuations of charging current and voltage are <0.64 and 2.12% in the whole charging profile. Moreover, the performance of two WPT chargers connected with one HFI hints that massive EBs can be charged with only one HFI.

Multilayer planar inductor array based angular position sensor for cryogenic application

The design, development and testing of a cryogenically operated multilayer planar inductor array based eddy current angular position/rotation transducer is claimed. An array of 4 multi-layered coils is used to divide the 360° into four sectors of 90° each. Switching between each of the inductor is done by a cold electronics based multiplexer circuit coupled to an unbuffered inverter LC oscillator. The angular displacement is a function of frequency of cold electronic LC oscillator. The pickup coil forms the inductor of the oscillator which is operated down to 4.2 K and uses thermal cycled stable components. The change in frequency as a function of angular displacement was calibrated at cryogenic temperatures. The developed sensor was found to have good thermal stability, sensitivity and repeatability over the entire cryogenic range.

Optimization of the Passive Components for an S-LCC Topology-Based WPT System for Charging Massive Electric Bicycles

Electric bicycles (EBs) are becoming increasingly popular in some regions such as China and Europe. However, wireless power transfer (WPT) for charging massive EBs poses a challenge related to the cost of WPT system (WPTS), especially in China, where EBs application is so sensitive to the product price. This paper presents an optimization method of the passive components for the S- LCC topology to decrease the cost of the overall system. With the novel method, the number of passive components can be optimized to the minimum and still with constant current and constant voltage outputs. A novel compensation method with an inductor array is also proposed to guarantee an inductive input impedance of WPTS, achieving soft switching and reducing the high switching losses of the high-frequency inverter (HFI). To demonstrate the validity of the proposed methods, an experimental setup is built. The performance of two WPTS indicates that massive EBs can be charged with only one HFI, and the cost of the overall system decreases accordingly.

A high output power and low phase noise GaN HEMT VCO with array of switchable inductors

SummaryThis paper presents cross‐coupled voltage‐controlled oscillators (VCOs) involving array of switchable inductors (i.e., N = 1 and N = 2 switchable inductors) and implemented using gallium‐nitride high electron mobility transistors on Si substrate technology for worldwide interoperability for microwave access applications. Band selection and coarse frequency tuning were achieved using the array of switchable inductors, whereas fine tuning was controlled using varactors. Two bands were obtained using the one‐stage switchable inductor VCO operating in the ranges 3.41–3.57 GHz and 3.85–3.94 GHz. The VCO output power (Pout) was 21.8 dBm at 3.57 GHz from a 10‐V power supply. Four continuous bands were obtained using the two‐stage switchable inductors VCO operating in the range of 3.16–3.4, 3.25–3.64, 3.48–3.71 and 3.64–3.9 GHz, respectively. An additional band was generated by fine‐tuning the inductance through mutual coupling between the transmission line and one of the inductors. The proposed two‐stage switchable inductors VCO provided a 21% tuning range at frequencies ranging with a control voltage ranging from 12 to 20 V, a low phase noise of −123 dBc/Hz at a 1‐MHz offset from a 3.3‐GHz carrier and a Pout of 21 dBm at 3.5 GHz from a 10‐V power supply. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Modeling Intracochlear Magnetic Stimulation: A Finite-Element Analysis.

This study models induced electric fields, and their gradient, produced by pulsatile current stimulation of submillimeter inductors for cochlear implantation. Using finite-element analysis, the lower chamber of the cochlea, scala tympani, is modeled as a cylindrical structure filled with perilymph bounded by tissue, bone, and cochlear neural elements. Single inductors as well as an array of inductors are modeled. The coil strength (~100 nH) and excitation parameters (peak current of 1-5 A, voltages of 16-20 V) are based on a formative feasibility study conducted by our group. In that study, intracochlear micromagnetic stimulation achieved auditory activation as measured through the auditory brainstem response in a feline model. With respect to the finite element simulations, axial symmetry of the inductor geometry is exploited to improve computation time. It is verified that the inductor coil orientation greatly affects the strength of the induced electric field and thereby the ability to affect the transmembrane potential of nearby neural elements. Furthermore, upon comparing an array of micro-inductors with a typical multi-site electrode array, magnetically excited arrays retain greater focus in terms of the gradient of induced electric fields. Once combined with further in vivo analysis, this modeling study may enable further exploration of the mechanism of magnetically induced, and focused neural stimulation.

Inductor array for minimising transfer efficiency decrease of wireless power transmission components at misalignment

A secondary coil design is reported for the stable transmission of wireless power in a misalignment situation. A coil array is applied to a secondary coil instead of typical single coil. When a misalignment occurs, the misalignment distance between an individual coil in the array and the primary coil is decreased relatively. Therefore, the sudden reduction in the inductive wireless power transmission (WPT) efficiency is mitigated. When the fabricated coil array transmits power, the maximum WPT efficiency improves by 56.45% compared with the typical single coil. The frequency band of the proposed array is wider, and this system can stably transmit power.

Integrated Ferrite Film Inductor for Power System-on-Chip (PowerSoC) Smart Phone Applications

An array of ferrite and air-core inductors was fabricated on silicon wafer to characterize inductor performance. The 1 μm and 2.5 μm thick ferrite films for the fabrication of inductors were prepared by dc magnetron sputtering. The inductance of the ferrite inductor increased with the thickness of ferrite film from 45.5 nH for 1 μm thick ferrite to 50 nH for 2.5 μm thick ferrite. The maximum Q-factor was obtained to be 59 at 2.87 MHz from 2.5 μm thick ferrite inductor, which is higher than 49.3 at 2.26 MHz for 1 μm thick ferrite inductor and 23.2 at 1.56 MHz for air-core inductor. Superimposed dc current of 1 μm and 2.5 μm thick ferrite inductors was estimated to be 2.5 A and 2.15 A, respectively, corresponding to a 5% drop in L at 10 MHz. In addition, the power efficiency of the buck dc-dc converter based on the studied ferrite inductors was calculated to be 91.7% for 2.5 μm thick ferrite inductor and 90.1% for 1 μm thick ferrite inductor at load current of 0.647 A.

Tunable CMOS Power Amplifiers for Reconfigurable Transceivers

This paper presents three CMOS power amplifiers (PA) which realize wide-tunable output impedance matching. For realization of multi-standard and single-chip transceiver, the prototypes were fabricated by 0.18µm CMOS process. The proposed PAs can achieve a tunable impedance matching within a wide frequency range by utilizing a resistive feedback and parallel resonator with an inductor and capacitor array. Therefore, the proposed PA has a realization possibility of isolator-less PA which contributes to decrease die area including external component. In other words, the PAs have tunable impedance matching function at their output ends. With a 3.3-V supply, three power amplifiers can cover frequency ranges of 0.9-3.0GHz, 2.1-5.8GHz, and 5.7-9.7GHz, respectively. The PAs realize P1dB of 21dBm, Psat of 22dBm, and PAEpeak of larger than 23%. The proposed PAs present a potential to realize multi-band transceivers without isolators.

Distributed Impedance Network (Z-Network) DC–DC Converter

This paper presents a novel dc-dc converter incorporating a distributed impedance-source network (Z-source network, or Z-network) to achieve the buck (step-down) and boost (step-up) function of a transformer-isolated dc-dc converter. In this paper, the distributed impedance source network composed of an array of inductors and capacitors is coupled between power source and main switching devices. The great and unique feature about the distributed impedance source network dc-dc converter is that unlike the traditional V-source or I-source converters, it can be open- and short-circuited without damaging switching devices. Therefore, the desired buck and boost function can be achieved. Moreover, converter reliability can be greatly improved. A dc-dc converter using this proposed concept is built and tested. Its performances are verified with experimental results.

A wideband frequency synthesizer for a receiver application at multiple frequencies

An integer-N frequency synthesizer for a receiver application at multiple frequencies was implemented in 0.18 μm 1P6M CMOS technology. The synthesizer generates 2.57 GHz, 2.52 GHz, 2.4 GHz and 2.25 GHz local signals for the receiver. A wide-range voltage-controlled oscillator (VCO) based on a reconfigurable LC tank with a binary-weighted switched capacitor array and a switched inductor array is employed to cover the desired frequencies with a sufficient margin. The measured tuning range of the VCO is from 1.76 to 2.59 GHz. From the carriers of 2.57 GHz, 2.52 GHz, 2.4 GHz and 2.25 GHz, the measured phase noises are −122.13 dBc/Hz, −122.19 dBc/Hz, −121.8 dBc/Hz and −121.05 dBc/Hz, at 1 MHz offset, respectively. Their in-band phase noises are −80.09 dBc/Hz, −80.29 dBc/Hz, −83.05 dBc/Hz and −86.38 dBc/Hz, respectively. The frequency synthesizer including buffers consumes a total power of 70 mW from a 2 V power supply. The chip size is 1.5 × 1 mm2.

A 1.8–2.6 GHz CMOS VCO with switched capacitor array and switched inductor array

The design of a 1.76–2.56 GHz CMOS voltage-controlled oscillator (VCO) with switched capacitor array and switched inductor array is presented. Fabricated in 0.18 μm 1P6M CMOS technology, the VCO achieves a 37% frequency tuning range. The measured phase noise varies between −118.5 dBc/Hz and −122.8 dBc/Hz at 1 MHz offset across the tuning range. Power consumption is about 14.4 mW with a 1.8 V supply. Based on a reconfigurable LC tank with switched capacitor array and switched inductor array, the tuning range is analyzed and derived in terms of design parameters, yielding useful equations to guide the circuit design.

A 2 Gb/s Bi-Directional Inter-Chip Data Transceiver With Differential Inductors for High Density Inductive Channel Array

A 2Gb/s bi-directional inter-chip data transceiver is experimentally demonstrated for the first time in 180 nm CMOS technology. Two orthogonal differential inductor pairs are vertically overlapped to make a bi-directional channel. Using these channels, bi-directional communication system is established without any complex circuit techniques. The crosstalk interference problem in channel array is also considered. Differential inductors, due to their noise immunity can make shorter pitches possible in channel array. Compared with the data link with conventional inductor array, this proposed technique achieves 2 times higher channel density with the same speed.

Comparison Between Experimental Measurements and Numerical Simulations of Spheromak Formation in SSPX

Data from a recently installed insertable magnetic probe array in the Sustained Spheromak Physics Experiment (SSPX) [E. B. Hooper et al., Nucl. Fusion 39, 863 (1999)] is compared against NIMROD [C. R. Sovinec et al., J. Comp. Phys. 195, 355 (2004)], a full 3D resistive magnetohydrodynamic code that is used to simulate SSPX plasmas. The experiment probe consists of a linear array of chip inductors arranged in clusters that are spaced every 2 cm, and spans the entire machine radius at the flux conserver midplane. Both the experiment and the numerical simulations show the appearance, shortly after breakdown, of a column with a hollow current profile that precedes magnetic reconnection, a process essential to the formation of closed magnetic flux surfaces. However, there are differences between the experiment and the simulation in how the column evolves after it is formed. These differences are studied to help identify the mechanisms that eventually lead to closed-flux surfaces (azimuthally averaged) and flux amplification, which occur in both the experiment and the simulation.