Inductor and EMI filter including the same

Patent metadata

Field	Value
Publication number	US-11955262-B2
Application number	US-202217673245-A
Country	US
Kind code	B2
Filing date	Feb 16, 2022
Priority date	Jan 3, 2017
Publication date	Apr 9, 2024
Grant date	Apr 9, 2024

Abstract

An inductor includes a first magnetic body having a toroidal shape and having a ferrite; and a second magnetic body configured to be different from the first magnetic body and including a metal ribbon, wherein the second magnetic body includes an outer magnetic body disposed on an outer circumferential surface of the first magnetic body and an inner magnetic body disposed on an inner circumferential surface of the first magnetic body, and each of the outer magnetic body and inner magnetic body is wound in a plurality of layers in a circumferential direction of the first magnetic body.

First claim

What is claimed is:

1. A power board, comprising:
a board;
a circuit portion formed on the board; and
an EMI filter configured to be electrically connected to the circuit portion,
wherein the EMI filter comprises:
an inductor comprising:
a magnetic core; and
a coil disposed on a surface of the magnetic core, and

a capacitor,

wherein the magnetic core comprises:
a first magnetic body having a toroidal shape, the first magnetic body comprising ferrite;
a second magnetic body disposed on an inner side of the first magnetic body; and
a third magnetic body disposed on an outer side of the first magnetic body,
wherein the second magnetic body is formed in multiple layers in a diameter direction of the first magnetic body on an inner circumferential surface of the first magnetic body,
wherein the third magnetic body is formed in multiple layers in the diameter direction on an outer circumferential surface of the first magnetic body,

wherein a thickness of the first magnetic body is greater than a thickness of the second magnetic body in the diameter direction,
wherein a thickness of the third magnetic body is less than the thickness of the first magnetic body in the diameter direction, and
wherein, when a frequency of a current applied to the inductor is equal to or less than a critical frequency, a relative permeability of each of the second and third magnetic bodies is higher than a relative permeability of the first magnetic body.

2. The power board according to claim 1 , wherein the more the frequency of the current applied to the inductor approaches the critical frequency, the more a difference between the relative permeabilities of the first and second magnetic bodies decreases and the more a difference between the relative permeabilities of the first and third magnetic bodies decreases.

3. The power board according to claim 2 , wherein, when the frequency of the current applied to the inductor is equal to or greater than the critical frequency, the relative permeability of each of the second and third magnetic bodies is lower than the relative permeability of the first magnetic body.

4. The power board according to claim 3 , wherein the critical frequency ranges from 150 kHz to 250 kHz.

5. The power board according to claim 1 , wherein a thickness ratio between the second magnetic body and the first magnetic body in the diameter direction ranges from 1:80 to 1:16, and
wherein a thickness ratio between the third magnetic body and the first magnetic body in the diameter direction ranges from 1:80 to 1:16.

6. The power board according to claim 5 , wherein the thickness of each of the second magnetic body and the third magnetic body ranges from 190 μm to 410 μm.

7. The power board according to claim 6 , wherein each of the second magnetic body and the third magnetic body is wound in the range from 5 turns to 25 turns.

8. The power board according to claim 7 , wherein at least one of the second or third magnetic body includes a region in which the thickness thereof varies in the diameter direction.

9. The power board according to claim 8 , wherein each of the second magnetic body and the third magnetic body includes Fe—Si-based material.

10. The power board according to claim 1 , wherein the relative permeability of the first magnetic body ranges from 2,000 H/m to 15,000 H/m, and
wherein each of the relative permeability of the second magnetic body and the relative permeability of the third magnetic body ranges from 2,500 H/m to 150,000 H/m.

11. The power board according to claim 1 , further comprising a resin layer disposed between the inner circumferential surface of the first magnetic body and the second magnetic body and between the outer circumferential surface of the first magnetic body and the third magnetic body.

12. The power board according to claim 11 , wherein the multiple layers of the second magnetic body are integrally formed, and
wherein the multiple layers of the third magnetic body are integrally formed.

13. The power board according to claim 1 , wherein a height of at least one of the second or third magnetic body is different from a height of the first magnetic body in a direction perpendicular to the diameter direction.

14. The power board according to claim 13 , wherein the height of the at least one of the second or third magnetic body is less than the height of the first magnetic body to expose at least one part of a surface of the first magnetic body.

15. The power board according to claim 1 , wherein a saturation magnetic flux density of each of the second magnetic body and the third magnetic body is greater than a saturation magnetic flux density of the first magnetic body.

16. The power board according to claim 1 , wherein the thickness of each of the second magnetic body and the third magnetic body in the diameter direction ranges from 190 μm to 210 μm.

17. The power board according to claim 1 , wherein the outer side of the first magnetic body is adhered to the third magnetic body by a first adhesive, and
wherein the inner side of the first magnetic body is adhered to the second magnetic body by a second adhesive.

18. The power board according to claim 17 , wherein each of the first and second adhesives includes at least one of epoxy-based resin, acrylic resin, silicon-based resin, or varnish.

19. The power board according to claim 1 , wherein the third magnetic body includes a plurality of areas having different numbers of the multiple layers.

20. A display device comprising the power board of claim 1 .

Assignees

• Lg Innotek Co Ltd

Inventors

• Lee Mi Jin
• Song Ji Yeon
• Kim Yu Seon
• Lim Jong Wook
• Bae Seok
• Lee Sang Won

Classifications

• H01F1/34 Primary

  non-metallic substances, e.g. ferrites · CPC title

• H01F3/04

  made from strips or ribbons · CPC title

• H01F3/08

  made from powder (powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06) · CPC title

• H01F17/0013 Primary

  with stacked layers · CPC title

• H01F17/06

  with core substantially closed in itself, e.g. toroid · CPC title