Method and apparatus for achieving galvanic isolation in package having integral isolation medium

• US 8,674,418 B2
• Filed: 08/19/2011
• Issued: 03/18/2014
• Est. Priority Date: 08/19/2011
• Status: Active Grant

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Poddar, Anindya, Prabhu, Ashok S., Johnson, Peter, Khanolkar, Vijaylaxmi
• Primary Examiner(s): MITCHELL, JAMES M
• Application Number:
  US13/214,069
• Publication Number:
  US 20130043970A1
• Time in Patent Office: 942 Days
• Field of Search: None
• US Class Current: 257/294
• CPC Class Codes: H01F 17/0013 with stacked layers
• CPC Class Codes: H01F 2017/008 Electric or magnetic shielding of printed inductances
• CPC Class Codes: H01F 27/32 Insulating of coils, windings, or parts thereof
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10

Abstract

An inductor device having an improved galvanic isolation layer arranged between a pair of coil and methods of its construction are described.

Claims

1. A galvanic isolation stack having improved galvanic isolation properties, the substrate comprising:

a base support;

a galvanic isolation medium arranged above the base support and the galvanic isolation medium having a high dielectric strength;

wherein the galvanic isolation stack comprises a device comprising a first electrical element and a second electrical element arranged such that the galvanic isolation medium is arranged between the first electrical element and the second electrical element;

wherein the galvanic isolation material is a borosilicate glass material; and

wherein the first electrical element comprises a first coil element and the second electrical element comprises a second coil element arranged such that the device comprise an inductor device;

wherein the galvanic isolation medium is adhered in place using an adhesive material;

wherein the stack further comprises,

a first shielding element and a second shielding element, and

wherein the first coil element is arranged between the first shielding element and the galvanic isolation medium; and

wherein the second coil element is arranged between the second shielding element and the galvanic isolation medium.

2. The galvanic isolation stack of claim 1 wherein the galvanic isolation medium comprises a single material.

3. The galvanic isolation stack of claim 1 wherein the galvanic isolation medium comprises a laminate of more than one material.

4. The galvanic isolation stack of claim 1 wherein the stack comprises a third coil element arranged above the first coil element and further comprises a fourth coil element arranged below the second coil element.

5. The galvanic isolation stack of claim 1 wherein the stack further comprises an embedded galvanic isolation medium wherein,

the second coil is arranged on a supplementary substrate;

the galvanic isolation layer is arranged below the supplementary substrate;

the base support includes an attachment region and the first coil is arranged on the base support;

a spacer element arranged between the base support and the supplementary substrate and configured such that the first coil and the second coil are maintained in a spaced apart arrangement and such that the spacer circumscribes the attachment region of base support that exposes the attachment region; and

the galvanic isolation medium arranged in the attachment region of the first galvanic isolation structure.

6. The galvanic isolation stack of claim 5 further comprises a third coil element arranged above the first coil element and further comprises a fourth coil element arranged below the second coil element.

7. The galvanic isolation stack of claim 5 wherein the galvanic medium is adhered in place using an adhesive material.

8. The galvanic isolation stack of claim 5 wherein the embedded structure further comprises,

a first shielding element and a second shielding element, and

wherein the first coil element is arranged between the first shielding element and the galvanic isolation medium;

and

wherein the second coil element is arranged between the second shielding element and the galvanic isolation medium.

9. The galvanic isolation stack of claim 1, wherein the galvanic isolation substrate comprises a device wherein the first electrical circuit element and the second electrical circuit element comprise one of at least one of an inductive circuit element and a capacitive circuit element.

10. A method for forming an apparatus comprising a galvanic isolation stack having galvanic isolation properties, the method comprising:

providing a base support;

arranging a galvanic isolation medium above the base, the galvanic isolation medium comprising borosilicate glass material;

forming a first electrical circuit element and a second electrical circuit element arranged such that the galvanic isolation medium is arranged between the first electrical circuit element and the second electrical circuit element;

wherein, the first electrical circuit element comprises first coil element arranged above the galvanic isolation medium; and

the second circuit element comprises a second coil element arranged below the galvanic isolation medium thereby forming an inductor wherein the apparatus comprises an inductor device, and wherein the first electrical element comprises a primary coil of the inductor and the second electrical element comprises a secondary coil of the inductor, further comprising;

forming a first shielding element such that the first coil element is arranged between the first shielding the element and the galvanic isolation medium; and

forming a second shielding element such that the secondary coil element is arranged between the second shielding element and the galvanic isolation medium.

11. The method of claim 10 further comprising,

arranging a third coil element above the first coil element;

and

arranging a fourth coil element below the second coil element.

12. The method of claim 10 wherein said arranging of the galvanic isolation medium above the base support includes affixing it in place using adhesive.

13. The method of claim 10 wherein the galvanic isolation substrate comprises forming an embedded structure further comprising,

arranging a supplementary substrate above the galvanic isolation medium such that the galvanic isolation medium is arranged between the supplementary substrate and the base support;

and arranging the first coil in the supplementary substrate.

14. The method of claim 13 wherein, the base support includes an attachment region, and

arranging a spacer element so that it lies between the base support and the supplementary substrate and wherein the attachment region lies within a space defined by the spacer and wherein the galvanic isolation medium is mounted with the attachment region of the base support.

15. The method of claim 13 wherein the spacer;

includes an inner aperture arranged such that the inner aperture circumscribes at least a portion of the attachment region of the base support; and

wherein the arranging of the spacer is conducted such that the galvanic isolation medium is arranged within the inner aperture of the spacer and between the base support and the first supplementary substrate.