Galvanic isolation of integrated closed magnetic path transformer with bt laminate

Patent metadata

Field	Value
Publication number	US-2020211754-A1
Application number	US-201816236571-A
Country	US
Kind code	A1
Filing date	Dec 30, 2018
Priority date	Dec 30, 2018
Publication date	Jul 2, 2020
Grant date	—

Abstract

A transformer respectively includes a first isolation barrier, a first inductive element, a second isolation barrier, and a second inductive element. The first isolation barrier and second isolation barrier each comprise multiple isolation layers. The transformer also includes magnetic material including a top magnetic portion disposed above the first isolation barrier. The transformer also includes a bottom magnetic portion disposed below the second inductive element; The transformer further includes an intermediary magnetic portion extending from the top magnetic portion to the bottom magnetic portion via a through-hole within the first isolation barrier, first inductive element, second isolation barrier, and second inductive element. The transformer yet further includes at least one lateral magnetic portion extending from the top magnetic portion to the bottom magnetic portion. The at least one lateral magnetic portion is disposed laterally from the first isolation barrier, first inductive element, second isolation barrier, and second inductive element.

First claim

What is claimed is:

1 . A transformer comprising:
a first isolation barrier extending in an axial direction, wherein the first isolation barrier comprises at least two first isolation layers; a first inductive element disposed below the first isolation barrier and extending in the axial direction; a second isolation barrier disposed below the first inductive element and extending in the axial direction, wherein the second isolation barrier comprises at least two second isolation layers; a second inductive element disposed below the second isolation barrier and extending in the axial direction; and magnetic material comprising:
a top magnetic portion disposed above the first isolation barrier and extending in the axial direction;
a bottom magnetic portion disposed below the second inductive element and extending in the axial direction;
an intermediary magnetic portion extending from the top magnetic portion to the bottom magnetic portion via a through-hole within the first isolation barrier, first inductive element, second isolation barrier, and second inductive element; and
at least one lateral magnetic portion extending from the top magnetic portion to the bottom magnetic portion, wherein the at least one lateral magnetic portion is disposed laterally from the first isolation barrier, first inductive element, second isolation barrier, and second inductive element in the axial direction.

2 . The transformer of claim 1 , wherein the through-hole and intermediary magnetic portion extends in a direction normal to the axial direction.

3 . The transformer of claim 1 , wherein the at least one lateral magnetic portion extends in a direction normal to the axial direction.

4 . The transformer of claim 1 , wherein the at least one lateral magnetic portion comprises only a single lateral magnetic portion, and wherein a portion of each of the first isolation barrier, first inductive element, second isolation barrier, and second inductive element is positioned between the intermediary magnetic portion and the single lateral magnetic portion.

5 . The transformer of claim 1 , wherein the at least one lateral magnetic portion comprises two lateral magnetic portions, and wherein the first isolation barrier, first inductive element, second isolation barrier, and second inductive element are positioned between the two lateral magnetic portions.

6 . The transformer of claim 1 , wherein each of the at least two first isolation layers comprises pre-preg.

7 . The transformer of claim 6 , wherein the pre-preg comprises bismaleimide triazine (BT).

8 . The transformer of claim 1 , wherein each of the at least two second isolation layers comprises pre-preg.

9 . The transformer of claim 8 , wherein the pre-preg comprises BT.

10 . The transformer of claim 1 , wherein each of the first inductive element and second inductive element comprises only a single layer coil.

11 . The transformer of claim 1 , wherein the first inductive element comprises two layer coils connected in series with each other.

12 . The transformer of claim 1 , wherein the second inductive element comprises two layer coils connected in series with each other.

13 . The transformer of claim 1 , wherein each of the first inductive element and second inductive element is formed in one or more dielectric laminate layers.

14 . The transformer of claim 1 , wherein a thickness of the first isolation barrier is between 70 μm and 130 μm in a direction normal to the axial direction.

15 . The transformer of claim 1 , wherein a thickness of the second isolation barrier is between 100 μm and 170 μm in a direction normal to the axial direction.

16 . The transformer of claim 1 , wherein a thickness of the transformer is between 800 μm and 1200 μm in a direction normal to the axial direction.

17 . The transformer of claim 1 , wherein the intermediary magnetic portion comprises a beveled upper portion adjacent the top magnetic portion, and wherein a filler is disposed between the beveled upper portion and the top magnetic portion.

18 . The transformer of claim 17 , wherein the filler comprises epoxy.

19 . The transformer of claim 1 , wherein at least one lateral edge of the first isolation barrier is not disposed laterally from the at least one lateral magnetic portion in the axial direction.

20 . A surface-mounted integrated circuit (IC) package comprising the transformer of claim 1 .

21 . A small outline integrated circuit (SOIC) package comprising the transformer of claim 1 .

22 . A transformer comprising:
a first isolation barrier, wherein the first isolation barrier comprises at least two first isolation layers; a first inductive element disposed below the first isolation barrier; a second isolation barrier disposed below the first inductive element, wherein the second isolation barrier comprises at least two second isolation layers; a second inductive element disposed below the second isolation barrier; and magnetic material comprising:
a top magnetic portion disposed above the first isolation barrier;
a bottom magnetic portion disposed below the second inductive element;
an intermediary magnetic portion extending from the top magnetic portion to the bottom magnetic portion via a through-hole within the first isolation barrier, first inductive element, second isolation barrier, and second inductive element; and
at least one lateral magnetic portion extending from the top magnetic portion to the bottom magnetic portion, wherein the at least one lateral magnetic portion is disposed laterally from the first isolation barrier, first inductive element, second isolation barrier, and second inductive element.

23 . The transformer of claim 22 , wherein each of the at least two first isolation layers and each of the at least two second isolation layers comprise pre-preg.

24 . The transformer of claim 23 , wherein the pre-preg comprises BT.

25 . The transformer of claim 22 , wherein at least one lateral edge of the first isolation barrier is not disposed laterally from the at least one lateral magnetic portion.

Assignees

• Texas Instruments Inc

Inventors

• Zhang Zhemin
• Massolini Roberto Giampiero
• Mullenix Joyce Marie

Classifications

• H10W90/00

  Package configurations · CPC title

• H01F2027/2809

  on stacked layers · CPC title

• H01F2027/2819

  Planar transformers with printed windings, e.g. surrounded by two cores and to be mounted on printed circuit · CPC title

• H01F19/08 Primary

  Transformers having magnetic bias, e.g. for handling pulses · CPC title

• H01F2019/085

  Transformer for galvanic isolation · CPC title