Dual fuse link thin film fuse

• US 7,477,130 B2
• Filed: 01/28/2005
• Issued: 01/13/2009
• Est. Priority Date: 01/28/2005
• Status: Expired due to Fees

• Current Assignee: Littlefuse Incorporated
• Original Assignee: Littelfuse Incorporated
• Inventors: Fukushige, Yasuhiro, Wally, Pablo
• Primary Examiner(s): Vortman; Anatoly
• Application Number:
  US11/046,367
• Publication Number:
  US 20060170528A1
• Time in Patent Office: 1,446 Days
• Field of Search: 337/297, 337/283, 337/284, 337/293, 337/161, 337/271
• US Class Current: 337/297
• CPC Class Codes: H01H 2085/0414 Surface mounted fuses
• CPC Class Codes: H01H 2085/0555 Input terminal connected to a plurality of output terminals, e.g. multielectrode
• CPC Class Codes: H01H 85/0411 Miniature fuses
• CPC Class Codes: H01H 85/046 Fuses formed as printed circuits
• CPC Class Codes: H01H 85/24 Means for preventing insertion of incorrect fuse

Abstract

A surface mount fuse having a plurality of fusible links is provided. The links are located on opposite sides of an insulative substrate or one otherwise thermally insulated or decoupled from one another. The fuse links entered to terminals that can be asymmetrically secured to the substrate to discourage improper mounting. The fuse protects multiple different circuits or loads having a same common or grounded line.

Claims

1. A surface mount fuse comprising:

an insulative substrate;

a first terminal secured to the substrate;

a second terminal secured to the substrate;

a third terminal secured to the substrate;

a first fuse link connected electrically to the first and second terminals; and

a second fuse link connected electrically to the third terminal,

wherein the first fuse link is disposed on a top surface of the substrate and the second fuse link is disposed on a bottom surface of the substrate.

2. The surface mount fuse of claim 1, wherein at least a majority of the first terminal and at least a majority of the second terminal are located on the top surface of the substrate and at least a majority of the third terminal is located on the bottom surface of the substrate.

3. The surface mount fuse of claim 1, wherein the substrate further includes side surfaces, and wherein at least one of the terminals extends along multiple surfaces of the substrate.

4. The surface mount fuse of claim 1, wherein at least one of the terminals extends along opposite side surfaces of the substrate.

5. The surface mount fuse of claim 1, wherein the fuse links have different current ratings.

6. The surface mount fuse of claim 1, wherein the fuse links have approximately the same current rating.

7. The surface mount fuse of claim 1, which includes a fourth terminal connected electrically to the second fuse link and the third terminal.

8. The surface mount fuse of claim 1, wherein at least one additional portion of the insulative substrate is metallized for purposes of solderability or manufacturability.

9. The surface mount fuse of claim 1, wherein the insulative substrate is made of a material selective from the group consisting of:

FR-4, epoxy resin, ceramic, resin coated foil, polytetraflouroethylene, polyimide and glass.

10. The surface mount fuse of claim 1, wherein at least one of the terminals and fuse links is copper.

11. The surface mount fuse of claim 1, wherein at least one of the fuse links includes a fuse element that provides a point at which the fuse link opens upon an overcurrent condition.

12. The surface mount fuse of claim 11, wherein the fuse element includes a plurality of metals.

13. The surface mount fuse of claim 1, wherein the terminals and fuse links are applied to the substrate via a process selected from the group consisting of:

plating and adhesion.

14. The surface mount fuse of claim 1, wherein at least one of the fuse links is covered with a protective coating.

15. The surface mount fuse of claim 1, wherein the first and second fuse links terminate at three corners and a side of the substrate.

16. The surface mount fuse of claim 15, wherein a fourth corner of the substrate is also metallized for manufacturability or solderability.

17. The surface mount fuse of claim 1, wherein the first and second fuse links are located with respect to each other in a non-symmetrical arrangement.

18. The surface mount fuse of claim 1, wherein the first and second fuse links are located with respect to each other in a misalignment arrangement.

19. A method of providing circuit protection comprising the steps of:

placing differently rated surface-mounted fuse links on different surfaces of a single insulative substrate; and

configuring terminals communicating electrically with the fuse links differently to prevent improper mounting of the terminals, wherein configuring the terminals differently includes extending the terminals communicating with a first one of the fuse links to different corners of the substrate and extending the terminals communicating with a second one of the fuse links to a side of the substrate and to either (i) another side of the substrate or (ii) another corner of the substrate.