Microfabrication and Characteristics of Low-Power High-Performance Magnetic Thin-Film Transformers

Yun, Eui‐Jung; Jung, Myunghee; Cheon, Chae Il; Nam, Hyoung Gin

doi:10.1109/tmag.2003.821119

Cited by 24 publications

(13 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, the device used works in a very large frequency range compared with the components listed in the table. It can also be observed from Table I that the quality of our transformer is highly improved compared with those developed in [18]- [20]. Advantages of the interleaved transformer are as follows: 1) good coupling factor for small magnetic core thicknesses (k = 0.95 for E yig = 10 μm); 2) easy technological implementation because the manufacture uses classical micro-technology steps as for planar inductances; 3) magnetic shielding.…”

Section: Chosen Solutionsmentioning

confidence: 91%

Design and Study of Interleaved and Face to Face Magnetic Microtransformers

Youssouf

Kahlouche

Soultan

et al. 2014

IEEE Trans. Electron Devices

View full text Add to dashboard Cite

The aim of this paper is to compare two types of microtransformers using the High Frequency Structural Simulation simulator. Interleaved and face to face transformers were studied for applications in dc/dc converters and variable speed drive. These transformers have a magnetic material core (yttrium iron garnet) and square spiral windings. The main purpose of the use of magnetic material is to increase the magnetizing inductance L F and the coupling factor k. For this, L F and k were studied by simulation as a function of turn spacing, magnetic, and insulating layer thicknesses. The results presented were compared with recently published works. An important improvement of the main properties was observed in the frequency range (10-100 MHz). The interleaved transformer properties are equal to 0.95 and 0.80 µH for k and L F parameters, which corresponds to an 0.05 µH/mm 2 inductance area ratio (L F / A), whereas for the face to face transformer k and L F are equal to 0.9 and 0.78 µH for an 0.08 µH/mm 2 inductance area ratio. Interleaved transformers were manufactured and characterized. Results show close agreement between simulation and measurement results.Index Terms-Coupling factor, face to face transformer, interleaved transformer, magnetic material.

show abstract

Section: Chosen Solutionsmentioning

confidence: 91%

Design and Study of Interleaved and Face to Face Magnetic Microtransformers

Youssouf

Kahlouche

Soultan

et al. 2014

IEEE Trans. Electron Devices

View full text Add to dashboard Cite

show abstract

“…Electroplated permalloy (Ni81Fe19) has been widely used for magnetic flux concentrators [1], [2] and micro transformers [3]- [7] due to their high magnetic permeability and small coercivity.…”

Section: Introductionmentioning

confidence: 99%

Effect of Substrate Temperature on Magnetic Properties of Electroplated 82Ni–15Fe–3W Alloy Films

2016

View full text Add to dashboard Cite

Nanocrystalline soft magnetic Ni-Fe-W alloy films are electroplated by applying different substrate temperature. In this study, the effect of substrate temperatures on the magnetic properties is investigated. The morphology and composition of the plated layers are determined by atomic force microscope and scanning electron microscope equipped with an energy dispersive X-ray spectroscopy detector, respectively. Structure and average grain size are characterized by the X-ray diffraction analysis. Magnetic properties of the plated alloy are determined by using the vibrating sample magnetometer. The results show that the coercivity and relative permeability of the plated films can be optimized by changing the substrate temperature. The lowest coercivity value of 257 A/m and high relative permeability value of 487 are obtained at substrate temperature value of 5 ºC. Plated alloy films have face centered cubic structure. Additionally, an increasing in the substrate temperature results in an increase in the strain and roughness.

show abstract

“…As long as magnetic flux from the primary winding has a low reluctance closed path through which it can return (North to South pole) and this path is shared with the secondary winding, the device will behave as expected. Many microfabricated transformer designs have non-critical geometries because they use magnetic core materials ( [32], [33], [34], [35], [36]), but also have complicated fabrication processes to reduce losses. However, as the frequency of the flux increases, the permeability of ferrites will become unstable and approach the permeability of vacuum ( see FIG.…”

Section: Introductionmentioning

confidence: 99%

Modeling and Testing of Ethernet Transformers

et al. 2009

View full text Add to dashboard Cite

Twisted-pair Ethernet is now the standard home and office last-mile network technology. For decades, the IEEE standard that defines Ethernet has required electrical isolation between the twisted pair cable and the Ethernet device. So, for decades, every Ethernet interface has used magnetic core Ethernet transformers to isolate Ethernet devices and keep users safe in the event of a potentially dangerous fault on the network media. The current state-of-the-art Ethernet transformers are miniature (<5mm diameter) ferrite-core toroids wrapped with approximately 10 to 30 turns of wire. As small as current Ethernet transformers are, they still limit further Ethernet device miniaturization and require a separate bulky package or jack housing. New coupler designs must be explored which are capable of exceptional miniaturization or on-chip fabrication.This dissertation thoroughly explores the performance of the current commercial Ethernet transformers to both increase understanding of the device"s behavior and outline performance parameters for replacement devices. Lumped element and distributed circuit models are derived; testing schemes are developed and used to extract model parameters from commercial Ethernet devices. Transfer relation measurements of the commercial Ethernet transformers are compared against the model"s behavior and it is found that the tuned, distributed models produce the best transfer relation match to the measured data.Process descriptions and testing results on fabricated thin-film dielectric-core toroid transformers are presented. The best results were found for a 32-turn transformer loaded with 100Ω, the impedance of twisted pair cable. This transformer gave a flat response from about 10MHz to 40MHz with a height of approximately 0.45. For the fabricated transformer structures, theoretical methods to determine resistance, capacitance and inductance are presented. A special analytical and numerical analysis of the fabricated transformer inductance is presented. Planar cuts of magnetic slope fields around the dielectric-core toroid are shown that describe the effect of core height and winding density on flux uniformity without a magnetic core.

show abstract

Microfabrication and Characteristics of Low-Power High-Performance Magnetic Thin-Film Transformers

Cited by 24 publications

References 10 publications

Design and Study of Interleaved and Face to Face Magnetic Microtransformers

Design and Study of Interleaved and Face to Face Magnetic Microtransformers

Effect of Substrate Temperature on Magnetic Properties of Electroplated 82Ni–15Fe–3W Alloy Films

Modeling and Testing of Ethernet Transformers

Contact Info

Product

Resources

About