WO1996017360B1

WO1996017360B1 - Planar pulse transformer

Info

Publication number: WO1996017360B1
Application number: PCT/US1995/015273
Authority: WO
Filing date: 1995-11-21
Publication date: 1996-08-29

Abstract

A planar pulse transformer is formed upon a substrate (20) having at leat one opening (22) formed therein and has a magnetically permeable core (10) having at least one portion thereof disposed within the opening of the substrate. Preferably, at least one primary winding (150) and at least one secondary winding (152) at least partially encircle the core. The primary and secondary windings are comprised entirely of metallization layers so as to simplify the fabrication process and reduce costs.

Claims

AMEND ED CLAIMS[received by the International Bureau on 11 June 19% (11.06.96); original claims 1, 2, 4 and 9-13 cancelled; original claims 3 and 5-8 amended; new claims 14-19 added (2 pages)]

1. CANCELED.

2. CANCELED.

3. (Amended) The transformer as recited in Claim 14 wherein said substrate comprises a ceramic substrate.

4. CANCELED.

5. The transformer as recited in Claim 14 wherein said core is comprised of a ferrite material.

6. The transformer as recited in Claim 14 wherein at least one of said primary and secondary windings comprise a plurality of turns.

7. The transformer as recited in Claim 14 wherein said at least one primary winding is comprised of a plurality of primary windings.

8. The transformer as recited in Claim 14 wherein said at least one secondary winding is comprised of a plurality of secondary windings.

9. CANCELED.

10. CANCELED.

11. CANCELED.

12. CANCELED.

13. CANCELED.

14. (New) A transformer comprising: a) a generally planar substrate having two openings formed therein; b) a magnetically permeable core comprising: i) an I core section; -13- ii) a U core section having two legs; iii) wherein said U core section is positioned such that each leg thereof is disposed within one of the two openings of said substrate and said I core section extends between the two legs, so as to capture a portion of said substrate intermediate said I core section and said U core section: and c) primary and secondary windings, at least one of said primary and secondary windings comprising a plurality of stacked metalization layers, each metalization layer comprising no more than one winding turn, adjacent metalization layers being separated by an insulating layer.

15. (New) The transformer as recited in Claim 14 wherein each said metalization layers comprises a winding turn which is generally a uniform distance from the U core along the length of the winding turn.

16. (New) The transformer as recited in Claim 14 wherein the winding turns of all of the metalization layers are approximately the same distance from the U core.

17. (New) The transformer as recited in Claim 14 wherein both of said primary and secondary windings comprise a plurality of stacked metalization layers, each metalization layer comprising approximately one winding turn, adjacent metalization layers being separated by an insulating layer.

18. (New) The transformer as recited in Claim 14 wherein said insulating layers comprise glass insulation layers.

19. (New) The transformer as recited in Claim 14 wherein the legs of said U core section extend beyond a surface of the substrate to position an interface of the I core section and the U core section away from the substrate so as to facilitate post assembly visual inspection of the interface. ^■ 14-

STATE-vlENrU DER ARTICLE 19

Japan 58-140104 does not appear to teach the use of a separate substrate, i.e., printed circuit board, upon which windings are formed, as is utilized in the present invention. Rather, Japan 58-140104 appears to disclose a transformer wherein the windings thereof are formed upon an integrated substrate which is folded in an accordion-like style, defining a plurality of folded layers upon which the windings thereof are formed. As such, the windings and core of the Japan 58-140104 device can be provided pre-attached to the core thereof, thereby completely eliminating the need to attach the core to windings formed upon a separate substrate, as is done in the present invention. Thus, the problem of insuring proper attachment of the I-core to the U-core thereof is not present with the device Japan 58-140104, since the I-core and U-core can be supplied pre-attached to one another prior to mounting of the transformer upon a printed circuit board.

Similarly, the Lugten device comprises a stand alone inductor wherein the windings thereof are integrally formed therewith, rather than being formed upon a separate substrate to which the core is subsequently attached. It is important to note that the present invention utilizes a separate substrate to which -15- it is attached in order to facilitate the formation of the windings thereof, rather than requiring the formation of separate windings. That is, the windings are formed upon the same substrate as that to which the core is attached, i.e., the printed circuit board. As such, the teaching of Lugten are complete contrary to those of the present invention and, indeed, tend to teach away therefrom. Further, if Lugten were to be combined with Japan 58-140104 and/or Mochizuki, the combination does not teach the use of one turn per layer formed upon the substrate to which the core is mounted.

As shown in Figure 6 of the Mochizuki patent, a U-core section is positioned for attachment to a substrate by passing the legs thereof through windows formed in the substrate and the I-core is positioned upon the opposite side of the substrate for attachment to the U-core. Since the U-core is not actually shown in an attached configuration, no teaching regarding the position of the interface of the U-core and the I-core relative to the substrate is provided.

Claim 19 specifically recites "the legs of the U core section extend beyond the surface of the substrate to position an interface of the I core section and the U core section away from the substrate so as to facilitate post assembly visual inspection of the interface", rather than merely that the interface is capable of such positioning. No inference can be made from Japan 58-140104 that the interface of the U-core and I-core sections thereof are so disposed as to facilitate visual inspection thereof absent an actual teaching to that effect.