Laminated common-mode choke coil

• US 6,356,181 B1
• Filed: 05/11/1998
• Issued: 03/12/2002
• Est. Priority Date: 03/29/1996
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kitamura, Hidekazu
• Primary Examiner(s): MAI, ANH T
• Application Number:
  US09/075,197
• Time in Patent Office: 1,401 Days
• Field of Search: 336/200, 336/223, 336/232
• US Class Current: 336/200
• CPC Class Codes: H01F 17/0013 with stacked layers
• CPC Class Codes: H01F 2017/0093 Common mode choke coil
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49073 by assembling coil and core

Abstract

A laminated common-mode choke coil is disclosed in which the coupling characteristics of first and second coil electrodes are improved so as to reduce normal mode impedance. A first coil electrode and a second coil electrode are laminated across an insulating layer. The first coil electrode is formed in a spiral shape in an area from a first external electrode to a first through-hole electrode (point L). A second coil electrode is formed in a spiral shape in an area from a third external electrode to a second through-hole electrode (point K). Both coil electrodes are spirally overlapped with each other in an area from point B to point K. Three coil embodiments are also disclosed.

Claims

1. A laminated common-mode choke coil comprising:

a laminated structure having a plurality of layers including a pair of magnetic substrates and a first insulating layer interposed between said pair of magnetic substrates;

first and second coil electrodes disposed on separate respective layers of said laminated structure;

first through fourth external electrodes located at edges of said laminated structure, said first external electrode being connected to one end of said first coil electrode, and said third external electrode being connected to one end of said second coil electrode; and

first and second through-hole electrodes through which said second external electrode is connected to the other end of said first coil electrode and said fourth external electrode is connected to the other end of said second coil electrode,

wherein said first and second coil electrodes are spiral in shape, and said first coil electrode extending from a connecting portion of said first external electrode and overlapping with said second coil electrode except at a position between said first and second through-hole electrodes, said first coil electrode and said second coil electrode being magnetically coupled.

2. A laminated common-mode choke coil according to claim 1, wherein said first coil electrode is linear from a position where it passes over said second through-hole electrode to a position where said first coil electrode reaches said first through-hole electrodes.

3. A laminated common-mode choke coil according to claim 1, wherein said magnetic substrates include Ni—

Zn ferrite.

4. A laminated common-mode choke coil according to claim 1, wherein said first insulating layer includes polyimide.

5. A laminated common-mode choke coil according to claim 1, wherein said first coil electrode substantially completely overlaps said second coil electrode in said laminated structure.

6. A laminated common-mode choke coil according to claim 1, wherein said coil electrodes include at least one of the following materials:

Ag, Pd, Al, Cr, Ni, Ti, Au, Cu, Pt and alloys thereof.

7. A laminated common-mode choke coil according to claim 1, wherein said first insulating layer comprises at least one of the following materials:

polyimide resin, epoxy resin, acrylic resin, circular olefin resin, Benzo Cyclo Butene resin, glass like SiO₂, and glass ceramics.

8. A laminated common-mode choke coil according to claim 1, wherein said magnetic substrates include at least one of Ni—

Zn ferrite, Mn—

Zn ferrite, and hexagonal ferrite.

9. A laminated common-mode choke coil according to claim 1, further comprising second and third insulating layers separating said first and second coils from said pair of magnetic substrates.

10. A laminated common-mode choke coil according to claim 9, wherein each of said second and third insulating layers comprises at least one of the materials of polyimide resin, epoxy resin, acrylic resin, circular olefin resin, Benzo Cyclo Butene resin, glass like SiO₂, and glass ceramics.

11. A laminated common-mode choke coil according to claim 9, wherein each of said first, second and third insulating layers include polyimide.

12. A laminated common-mode choke coil comprising:

a pair of first and second magnetic substrates;

a rectangular-prism-shaped laminated structure having first and second insulating layers laminated between the first and second magnetic substrates;

a first coil electrode located between the first magnetic substrate and the first insulating layer, and a first external electrode connected to one end of the first coil electrode;

a first lead electrode formed between the second insulating layer and the second magnetic substrate and electrically connected at one end to the other end of the first coil electrode;

a second external electrode connected to the other end of the first lead electrode;

a second coil electrode formed between the first and second insulating layers, and a third external electrode connected to one end of the second coil electrode;

a second lead electrode formed between the second insulating layer and the second magnetic substrate and electrically connected at one end to the other end of second coil electrode;

a fourth external electrode connected to the other end of the second lead electrode;

first through-hole electrodes formed inside the first and second insulating layers and connecting the other end of the first coil electrode and one end of the first lead electrode; and

a second through-hole electrode formed inside the second insulating layer and connecting the other end of the second coil electrode and one end of the second lead electrode.

13. A laminated common-mode choke coil according to claim 12, wherein said first and second external electrodes are positioned to be partially exposed from a first lateral surface of the laminated structure, and said third and fourth external electrodes are positioned to be partially exposed from a second lateral surface opposing the first lateral surface of the laminated structure.

14. A laminated common-mode choke coil according to claim 12, wherein said first coil electrode has a spiral shape in an area from the first external electrode to the first through-hole electrode, and said second coil electrode has a spiral shape in an area from the third external electrode to the second through-hole electrode.

15. A laminated common-mode choke coil according to claim 12, wherein said first coil electrode has a spiral configuration which extends from the first external electrode, overlaps with the second coil electrode, and extends beyond a position where the first coil electrode reaches the second through-hole electrode.

16. A laminated common-mode choke coil according to claim 12, wherein said coil electrodes include at least one of the following materials:

Ag, Pd, Al, Cr, Ni, Ti, Pt, Au, Cu and alloys thereof.

17. A laminated common-mode choke coil according to claim 12, wherein each of said first and second insulating layers comprises at least one of the following materials:

polyimide resin, epoxy resin, acrylic resin, circular olefin resin, Benzo Cyclo Butene resin, glass like SiO₂, and glass ceramics.

18. A laminated common-mode choke coil according to claim 12, wherein said magnetic substrates include at least one of Ni—

Zn ferrite, Mn—

Zn ferrite, and hexagonal ferrite.

19. A laminated common-mode choke coil comprising:

a laminated structure having a plurality of layers including a pair of magnetic substrates and a first insulating layer interposed between said pair of magnetic substrates; and

first and second coil electrodes disposed on separate respective layers of said laminated structure,

first through fourth external electrodes located at edges of said laminated structure, said first external electrode being connected to one end of said first coil electrode, and said third external electrode being connected to one end of said second coil electrode; and

first and second through-hole electrodes through which said second external electrode is connected to the other end of said first coil electrode and said fourth external electrode is connected to the other end of said second coil electrode,

wherein said second coil electrode is substantially completely contiguous to said first coil electrode in an overlapping relationship, said first coil electrode and said second coil electrode being magnetically coupled.

20. A laminated common-mode choke coil according to claim 19, wherein said first coil electrode has a spiral configuration which extends from a first external electrode, overlaps with the second coil electrode which has a substantially identical spiral configuration, and extends beyond a position where the first coil electrode reaches an end of said second coil electrode.

21. A laminated common-mode choke coil according to claim 19, wherein said coil electrodes include at least one of the following materials:

Ag, Pd, Al, Cr, Ni, Ti, Pt, Au, Cu and alloys thereof.

22. A laminated common-mode choke coil according to claim 19, wherein said first insulating layer comprises at least one of the following materials:

polyimide resin, epoxy resin, acrylic resin, circular olefin resin, Benzo Cyclo Butene resin, glass like SiO₂, and glass ceramics.

23. A laminated common-mode choke coil according to claim 19, wherein said magnetic substrates include at least one of Ni—

Zn ferrite, Mn—

Zn ferrite, or hexagonal ferrite.

24. A laminated common-mode choke coil according to claim 19, wherein said first coil electrode and said second coil electrode have substantially a same number of turns.

25. A laminated common-mode choke coil according to claim 19,

wherein said first coil electrode is formed on a first planar layer of said laminated structure, and

wherein said second coil electrode is formed on a second planar layer of said laminated structure.

26. A laminated common-mode choke coil according to claim 19, further comprising:

first and second external electrodes respectively connected to first and second ends of said first coil electrode; and

third and fourth external electrodes respectively connected to first and second ends of said second coil electrode.

27. A laminated common-mode choke coil comprising:

laminated structure having a plurality of layers including a pair of magnetic substrates;

a first insulating layer interposed between said pair of magnetic substrates;

first and second coil electrodes disposed on separate respective layers of said laminated structure;

first through fourth external electrodes located at edges of said laminated structure, said first external electrode being connected to one end of said first coil electrode, and said third external electrode being connected to one end of said second coil electrode; and

first and second through-hole electrodes through which said second external electrode is connected to the other end of said first coil electrode and said fourth external electrode is connected to the other end of said second coil electrode;

wherein said first coil electrode and said second coil electrode are magnetically coupled.

28. A laminated common-mode choke coil according to claim 27, wherein said coil electrodes include at least one of the following materials:

Ag, Pd, Al, Cr, Ni, Ti, Au, Cu, Pt and alloys thereof.

29. A laminated common-mode choke coil according to claim 27, wherein said first insulating layer comprises at least one of the following materials:

polyimide resin, epoxy resin, acrylic resin, circular olefin resin, Benzo Cyclo Butene resin, glass like SiO₂, and glass ceramics.

30. A laminated common-mode choke coil according to claim 27, wherein said magnetic substrates include at least one of Ni—

Zn ferrite, Mn—

Zn ferrite, or hexagonal ferrite.

31. A laminated common-mode choke coil comprising:

a laminated structure having a plurality of layers including a pair of magnetic substrates and a first, second and third insulating layer interposed between said pair of magnetic substrates;

first, second and third coil electrodes disposed on separate respective layers of said laminated structure;

first through sixth external electrodes located at edges of said laminated structure, said first external electrode being connected to one end of said first coil electrode, said third external electrode being connected to one end of said second coil electrode, and said fifth external electrode being connected to one end of said third coil electrode; and

first and second through-hole electrodes through which said second external electrode is connected to the other end of said first coil electrode, said fourth external electrode is connected to the other end of said second coil electrode, and said sixth external electrode is connected to the other end of said third coil electrode,

wherein said first, second and third coil electrodes are spiral in shape, said first coil electrode extends from a connecting portion of said first external electrode and overlaps with said second coil electrode except at a position between said first and second through-hole electrodes, said first coil electrode and said second coil electrode being magnetically coupled, and said second coil electrode extends from a connecting portion of said third external electrode and overlaps with said third coil electrode except at a position between said second and third through-hole electrodes.

32. A laminated common-mode choke coil according to claim 31, further comprising fourth and fifth insulating layers separating said first and third coils from said pair of magnetic substrates.

33. A laminated common-mode choke coil comprising:

a laminated structure having a plurality of layers including a pair of magnetic substrates and a first insulating layer interposed between said pair of magnetic substrates;

first and second coil electrodes disposed on separate respective layers of said laminated structure;

first through fourth external electrodes located at edges of said laminated structure, said first external electrode being connected to one end of said first coil electrode, and said third external electrode being connected to one end of said second coil electrode; and

first and second through-hole electrodes through which said second external electrode is connected to the other end of said first coil electrode and said fourth external electrode is connected to the other end of said second coil electrode,

wherein said first coil electrode has a spiral shape, including a terminal portion which extends between said first and second through-hole electrodes, and wherein said second coil electrode has a spiral shape which is identical to the shape of the first coil electrode except that it does not include said terminal portion, wherein said first and second coil electrodes are stacked in the laminated structure such that the first coil electrode directly overlaps said second coil electrode.