Methods and apparatus for isolation barrier with integrated magnetics for high power modules

• US 10,497,506 B2
• Filed: 12/18/2015
• Issued: 12/03/2019
• Est. Priority Date: 12/18/2015
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Massolini, Roberto Giampiero, Khanolkar, Vijaylaxmi, Mullenix, Joyce, Miftakhutdinov, Rais
• Primary Examiner(s): Enad, Elvin G
• Assistant Examiner(s): Barnes, Malcolm
• Application Number:
  US14/974,901
• Publication Number:
  US 20170178787A1
• Time in Patent Office: 1,446 Days
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/10 Sintering only
• CPC Class Codes: B22F 5/12 of wires of tubes B22F5/10
• CPC Class Codes: B22F 7/06 of composite workpieces or articles from parts, e.g. to form tipped tools B22F7/002 takes precedence
• CPC Class Codes: C22C 2202/02 Magnetic
• CPC Class Codes: H01F 2027/2809 on stacked layers
• CPC Class Codes: H01F 2027/2819 Planar transformers with printed windings, e.g. surrounded by two cores and to be mounted on printed circuit
• CPC Class Codes: H01F 27/24 Magnetic cores
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 27/288 Shielding
• CPC Class Codes: H01F 41/0206 Manufacturing of magnetic cores by mechanical means magnetic cores per se H01F27/24
• CPC Class Codes: H01F 41/04 for manufacturing coils coils for transformer or inductances H01F27/28
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/181 Encapsulation

Abstract

Methods and apparatus for isolation barrier with magnetics. In an example arrangement, an apparatus includes an isolation laminate including a dielectric core having a first surface and a second surface opposed to the first surface; at least one conductive layer configured as a first transformer coil overlying the first surface; a first dielectric layer surrounding the at least one conductive layer; a first magnetic layer overlying the at least one conductive layer; at least one additional conductive layer configured as a second transformer coil overlying the second surface; a second dielectric layer surrounding the at least one additional conductive layer; and a second magnetic layer overlying the at least one additional conductive layer. Methods for forming the isolation barriers and additional apparatus arrangements are also disclosed.

Claims

1. An apparatus, comprising:

a first dielectric layer having upper and lower surfaces;

at least one first conductive layer configured as a first transformer coil above the upper surface;

a first magnetic layer above the at least one first conductive layer;

a second dielectric layer between the at least one first conductive layer and the first magnetic layer;

at least one second conductive layer configured as a second transformer coil below the lower surface;

a second magnetic layer below the at least one second conductive layer, the first magnetic layer and the second magnetic layer configured to confine and focus the flux between the first transformer coil and the second transformer coil to increase an effective inductance between the first transformer coil and the second transformer coil by at least a factor of two;

a third dielectric layer between the at least one second conductive layer and the second magnetic layer; and

a third conductive layer forming an electromagnetic interference (EMI) shield between and isolated from the at least one first conductive layer and the at least one second conductive layer.

2. The apparatus of claim 1, wherein the EMI shield comprises a non-ferrous metal.

3. The apparatus of claim 1, further comprising:

a leadframe having a die attach pad in thermally conductive contact with the second magnetic layer to provide thermal transfer to the leadframe.

4. The apparatus of claim 1, wherein the first dielectric layer comprises BT resin.

5. The apparatus of claim 1, wherein the EMI shield comprises copper.

6. The apparatus of claim 1, wherein the first and second magnetic layers are formed from powdered magnetic material in a sintering operation.

7. The apparatus of claim 6, wherein the powdered magnetic material comprises ferrite material.

8. The apparatus of claim 1, wherein the first magnetic layer comprises magnetic material having a permeability of greater than about 1.

9. The apparatus of claim 1, wherein the first magnetic layer comprises a ferrous material.

10. The apparatus of claim 1, wherein the first magnetic layer comprises material including at least one of nickel and zinc.

11. The apparatus of claim 1, wherein the at least one first conductive layer comprises copper.

12. A packaged integrated circuit, comprising:

a metal leadframe having first and second portions; and

an isolation laminate mounted on a third portion of the metal leadframe and isolated from at least one of the first portion and the second portion, the isolation laminate comprising;

a first dielectric layer having a first surface and a second surface opposed to the first surface;

at least one first conductive layer configured as a first transformer coil above the first surface;

a first magnetic layer above the at least one first conductive layer;

a second dielectric layer between the at least one first conductive layer and the first magnetic layer;

at least one second conductive layer configured as a second transformer coil below the second surface;

a second magnetic layer below the at least one second conductive layer in conductive contact with the third portion of the metal leadframe, the first magnetic layer and the second magnetic layer configured to confine and focus the flux between the first transformer coil and the second transformer coil to increase an effective inductance between the first transformer coil and the second transformer coil by at least a factor of two;

a third dielectric layer between the at least one second conductive layer and the second magnetic layer; and

a third conductive layer forming an electromagnetic interference (EMI) shield between the at least one first conductive layer and the at least one second conductive layer.

13. The packaged integrated circuit of claim 12, further comprising:

a first circuit disposed on the first portion of the metal leadframe and coupled to the first transformer coil; and

a second circuit disposed on the second portion of the metal leadframe and coupled to the second transformer coil;

wherein the first circuit and the second circuit are galvanically isolated from one another, and signals from the first circuit are coupled to the second circuit by the first and second transformer coils.

14. The packaged integrated circuit of claim 12, wherein the isolation laminate comprises:

a dielectric layer formed between the EMI shield and one of the first and second magnetic layers.

15. The packaged integrated circuit of claim 14, wherein the EMI shield comprises a non-ferrous metal.

16. The packaged integrated circuit of claim 12, wherein the conductive contact is a thermally conductive contact.

17. The packaged integrated circuit of claim 12, wherein the first magnetic layer comprises a material that is one chosen from the group consisting essentially of ferrite material and metal-based magnetic material.

18. The packaged integrated circuit of claim 12, further comprising encapsulation material surrounding the metal leadframe and the isolation laminate.

19. A packaged integrated circuit, comprising:

at least one first conductive layer configured as a first transformer coil;

a first dielectric layer below the at least one first conductive layer;

at least one second conductive layer configured as a second transformer coil below the at least one first conductive layer;

a second dielectric layer above the at least one second conductive layer;

a conductive electromagnetic interference (EMI) shield between the first and second dielectric layers;

a first magnetic layer above the at least one first conductive layer;

a third dielectric layer between the at least one first conductive layer and the first magnetic layer;

a fourth dielectric layer below the at least one second conductive layer; and

a second magnetic layer below the fourth dielectric layer, the first magnetic layer and the second magnetic layer configured to confine and focus the flux of the first transformer coil and the second transformer coil so that an effective inductance between the first transformer coil and the second transformer coil is at least doubled.

20. The packaged integrated circuit of claim 19, further comprising:

a metal leadframe; and

the second magnetic layer below the fourth dielectric layer in thermally conductive contact with the metal leadframe.