Choke coil and electronic device using the same

• US 7,199,693 B2
• Filed: 01/14/2004
• Issued: 04/03/2007
• Est. Priority Date: 01/17/2003
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Imanishi, Tsunetsugu, Matsutani, Nobuya, Uematsu, Hidenori
• Primary Examiner(s): MAI, ANH T
• Application Number:
  US10/756,757
• Publication Number:
  US 20040145442A1
• Time in Patent Office: 1,175 Days
• Field of Search: 336/200, 336/223, 336/232, 336/83
• US Class Current: 336/200
• CPC Class Codes: H01F 2017/046 helical coil made of flat wire, e.g. with smaller extension of wire cross section in the direction of the longitudinal axis
• CPC Class Codes: H01F 2017/048 with encapsulating core, e.g. made of resin and magnetic powder
• CPC Class Codes: H01F 2027/2861 Coil formed by folding a blank
• CPC Class Codes: H01F 21/12 discontinuously variable, e.g. tapped
• CPC Class Codes: H01F 27/027 specially adapted for combination of signal type inductors or transformers with electronic circuits, e.g. mounting on printed circuit boards
• CPC Class Codes: H01F 27/292 Surface mounted devices

Abstract

The choke coil disclosed comprises: coils incorporated with terminals and intermediate taps manufactured of die cut metal plates; and a magnetic powder in which the coils are embedded.

Claims

1. A choke coil, comprising:

a metal plate having a folded portion, a first terminal, and a second terminal; and

a magnetic material in which the coils are embedded, with an insulation layer on the surface of the metal plate except the surfaces of the folded portion, the first terminal and the second terminal, wherein the metal plate additionally includes an intermediate tap, and the insulation layer is not on the intermediate tap.

2. The choke coil of claim 1, wherein the metal plate is formed by pressing or etching.

3. The choke coil of claim 1, wherein the magnetic material comprises a material selected from the group consisting of a ferrite magnetic material of;

a composite of ferrite magnetic powder and insulating resin; and

a composite of magnetic metal powder and an insulating resin.

4. The choke coil of claim 1, wherein at least one of terminals and intermediate tap of the coils are disposed across at least two surfaces among a bottom surface and adjacent surfaces.

5. The choke coil of claim 1, wherein marking of terminals and/or intermediate taps are provided on the magnetic material.

6. The choke coil of claim 1, wherein at least terminals and intermediate taps of the coil exposed to surfaces are provided with Ni as a foundation layer, and with one of solder layer and Sn layer as a surface layer.

7. The choke coil of claim 1, wherein the magnetic material is square pole shaped.

8. The choke coil of claim 1, wherein a coil having an intermediate tap, and a coil having no intermediate tap are embedded in the magnetic material.

9. The choke coil of claim 8, wherein the neighboring two coils are disposed such that the respective magnetic fluxes generated by current flow pass through the coil to opposite directions respectively.

10. The choke coil of claim 8, wherein the neighboring two coils are disposed such that respective magnetic fluxes generated by current flow pass through the coil to a same direction.

11. The choke coil of claim 8, wherein the coils are located such that at least two intermediate taps emerge in different directions.

12. The choke coil of claim 8, wherein the coils are located such that all intermediate taps emerge in a same direction.

13. The choke coil of claim 1, wherein a plurality of coils are embedded in the magnetic material.

14. The choke coil of claim 8, wherein an inductance of a plurality of the coil is incorporated with terminals and intermediate tap, and/or the coil incorporated with terminals are controlled to a predeterminate value by adjusting an interval between the coils.

15. The choke coil of claim 13, wherein an inductance of a plurality of the coil incorporated with the terminals and intermediate tap, and/or the coil incorporated with terminals are controlled to a predeterminate value by adjusting an interval between the coils.

16. The choke coil of claim 13, wherein the neighboring two coils are disposed such that respective magnetic fluxes generated by current flow pass through the coil to opposite directions respectively.

17. The choke coil of claim 13, wherein two adjacent coils are located such that respective magnetic fluxes generated by current flow pass through the two coils in a same direction.

18. The choke coil of claim 13, wherein the coils are located such that all intermediate taps emerge a same direction.

19. The choke coil of claim 13, wherein the coils are located such that at least two intermediate taps emerge in different directions.