Inductor devices – With supporting and/or spacing means between coil and core – Preformed insulation between coil and core
Reexamination Certificate
2000-11-28
2002-12-31
Mai, Anh (Department: 2832)
Inductor devices
With supporting and/or spacing means between coil and core
Preformed insulation between coil and core
C336S208000, C336S192000, C336S212000
Reexamination Certificate
active
06501362
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to ferrite cores and more particularly pertains to a new ferrite core for minimizing the circuit board footprint of a core-based component while also minimizing the total harmonic distortion exhibited by the component.
2. Description of the Prior Art
The use of ferrite cores is known in the prior art. The ferrite cores are situated in close proximity to coiled conductors to facilitate the flow of magnetic flux between the coils of a coiled conductor.
Some of the most popular prior art designs for ferrite coils are illustrated in
FIGS. 1A
,
1
B, and
1
C. These known core designs typically employ a cylindrical center leg and a horseshoe shaped outer leg. Variations include expanding the center leg along the increased gap, and placing additional breaks in the outer leg to enhance ventilation of the coiled conductor (FIG.
1
B), and increasing the gap between the ends of the outer leg (FIG.
1
C).
However, factors have combined to make these designs less than optimal for use in applications where circuit board space is at a premium, where the least amount of total harmonic distortion is desirable, and where interference between adjacent components should be minimized.
One area where this is especially true is in signal circuits of telecommunications applications, and one example is in the central telephone office installations of high speed telephone line service providers. The providers employ high-speed telephone line technologies such as Digital Subscriber Line (DSL), and variations of DSL such as ADSL, HDSL, SDSL, SHDSL, and MDSL, among others, for connecting customers through their conventional telephone lines to the internet and other networks. Because the provider must pay for the space occupied by the circuitry in the central telephone office, the trend has been toward miniaturization of the components mounted on the printed circuit boards of the circuits to minimize the occupied space. Miniaturization of the components not only permits more circuits, or telephone line connection ports, to be mounted on a circuit board, but also permits the circuit boards to be mounted in closer proximity to each other in a mounting rack. Thus, the trend has not only been to make the components smaller overall, but also shorter with respect to the height that the components protrude from the surface of the circuit board so that the boards can be mounted closer together in the mounting racks.
The miniaturization of the components, especially transformer and inductors and the ferrite cores employed in those transformers and inductors, has not been without its drawbacks. Smaller core sizes have required a greater number of conductor turns in the components. Increasing the number of turns in the components results in a number of detrimental effects, such as increased leakage inductance, increased distributive capacitance, increased capacitance between the primary and secondary windings of transformer components, and a general decrease in the bandwidth capacity of the components. Also, the total harmonic distortion exhibited by the newer core designs has been a concern, as well as the handling of DC bias.
In core configurations such as shown in
FIGS. 1A
,
1
B, and
1
C, the parts of the channel between the center leg and the outer leg where the width of the channel becomes larger, such as is present in these known cores below the center line (C) of the center leg, are more likely to magnetically saturate and are believed not to contribute significantly to the effective flux carrying capability of the core because the magnetic flux path length is longer than the path length in the parts of the core located above the center line (C).
The ferrite core according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing, provides an apparatus primarily developed for the purpose of minimizing the circuit board footprint of a core-based component while also minimizing the total harmonic distortion exhibited by the component.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of ferrite cores now present in the prior art, the present invention provides a new ferrite core construction wherein the same can be utilized for minimizing the circuit board footprint of a corebased component while also minimizing the total harmonic distortion exhibited by the component.
To attain this, the present invention generally comprises a back wall portion, a central wall portion, and an outside wall portion. The back wall portion has a front and a back, with a lower end, an upper end, and a pair of sides extending between the lower and upper ends. The central leg portion protrudes from the front of the back wall portion, and the central leg portion is substantially centrally located on the front of the back wall portion. The outside wall portion protrudes from the front of the back wall portion. In one aspect of the invention, the central leg portion is elongated along a first axis extending between the upper and lower ends of the back wall portion. In another aspect of the invention, the central leg portion is spaced from the lower edge of the back wall portion.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures. methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
The objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.
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patent
Arnold Eric J.
Hoffman Thomas K.
Kaardal & Leonard LLP
Mai Anh
Proehl Jeffrey A.
UMEC USA, Inc.
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