Protective device

• US 9,129,769 B2
• Filed: 09/03/2010
• Issued: 09/08/2015
• Est. Priority Date: 09/04/2009
• Status: Active Grant

• Current Assignee: Cyntec Co. Ltd. (Delta Electronics Incorporated)
• Original Assignee: Cyntec Co. Ltd. (Delta Electronics Incorporated)
• Inventors: Wang, Chung-Hsiung, Lin, Hung-Ming, Luo, Wen-Shiang, Liu, Chun-Tiao, Chen, Kuo-Shu
• Primary Examiner(s): Vortman, Anatoly
• Assistant Examiner(s): CRUM, JACOB R
• Application Number:
  US12/875,771
• Publication Number:
  US 20110057761A1
• Time in Patent Office: 1,831 Days
• Field of Search: 337/297
• US Class Current: 1/1
• CPC Class Codes: H01H 2085/0283 Structural association with a semiconductor device
• CPC Class Codes: H01H 2085/466 with remote controlled forced fusing
• CPC Class Codes: H01H 69/022 of printed circuit fuses
• CPC Class Codes: H01H 85/0047 Heating means
• CPC Class Codes: H01H 85/0241 Structural association of a fuse and another component or apparatus switches with built-in fuses H01H9/10, spark-gap arresters H01H85/44, transformers and inductances H01F27/402, capacitors H01G2/14, lamps H01K1/66, semiconductors H01L23/5256 or H01L23/62
• CPC Class Codes: H01H 85/0411 Miniature fuses
• CPC Class Codes: H01H 85/046 Fuses formed as printed circuits
• CPC Class Codes: H01H 85/048 Fuse resistors
• CPC Class Codes: H01H 85/11 with applied local area of a metal which, on melting, forms a eutectic with the main material of the fusible member, i.e. M-effect devices
• CPC Class Codes: H01H 85/48 Protective devices wherein the fuse is carried or held directly by the base

Abstract

A protective device including a substrate, a conductive section and a bridge element is provided. The conductive section is supported by the substrate, wherein the conductive section comprises a metal element electrically connected between first and second electrodes. The metal element serves as a sacrificial structure having a melting point lower than that of the first and second electrodes. The bridge element spans across the metal element in a direction across direction of current flow in the metal element, wherein the bridge element facilitates breaking of the metal element upon melting.

Claims

1. A protective device, comprising:

a substrate;

a conductive section supported by the substrate, wherein the conductive section comprises a metal element electrically connected between first and second electrodes, wherein the metal element serves as a sacrificial structure having a melting point lower than that of the first and second electrodes;

a bridge element spanning across the metal element in a first direction across a direction of current flow in the metal element, wherein the bridge element extends in the first direction farther than the metal element in the first direction and facilitates breaking of the metal element upon melting, wherein the bridge element is made of metal;

an intermediate support disposed directly below the metal element and directly above the substrate, wherein the intermediate support has no direct physical contact with any of the first electrode and the second electrode, and wherein at least one end of the bridge element is fixed to and in direct physical contact with the intermediate support; and

a housing disposed on the substrate and fully covering the metal element and the bridge element, wherein the metal element and the bridge element are located below a top of the housing,

wherein the metal element is located above the first and second electrodes and under the bridge element.

2. The protective device as in claim 1, wherein at least one end of the bridge element is fixedly supported on the substrate.

3. The protective device as in claim 2, wherein both ends of the bridge element are fixedly supported on the substrate.

4. The protective device as in claim 1, wherein both ends of the bridge element are fixed to and in physical contact with the intermediate support.

5. The protective device as in claim 1, wherein the bridge element comprises an elongated structure.

6. The protective device as in claim 5, wherein the elongated structure comprises an arc or a bending shape.

7. The protective device as in claim 1, further comprising an auxiliary medium having a portion disposed between the bridge element and the metal element.

8. The protective device as in claim 7, further comprising another auxiliary medium disposed between the metal element and the substrate, wherein said another auxiliary medium having a melting point lower than that of the metal element.

9. The protective device as in claim 7, further comprising a heat-generating element supported by the substrate, providing heat to at least the metal element and the auxiliary medium.

10. The protective device as in claim 9, wherein the bridge element and auxiliary medium are positioned in line with the heat generating element.

11. The protective device as in claim 9, wherein the heat-generating element is supported between the metal element and the substrate.

12. The protective device as in claim 9, wherein the heat-generating element is supported by a side of the substrate away from the metal element.

13. The protective device as in claim 1, further comprising an intermediate layer between the metal element and the intermediate support, wherein the intermediate layer has a fusing temperature lower than the melting temperature of the metal element.

14. The protective device as in claim 7, wherein the auxiliary medium is a flux or a solder layer.

15. The protective device as in claim 1, further comprising a heat insulation portion between a heat-generating element and the first and second electrodes, wherein heat transfer to the intermediate support is at a higher rate than that to the first and second electrodes.

16. The protective device as in claim 1, wherein the intermediate support is an extension of a third electrode coupled to a heat-generating element.

17. The protective device as claimed in claim 1, wherein the substrate comprise a first insulating block, and a second insulating block under the first and second electrodes, wherein a thermal conductivity coefficient of the first insulating bock is greater than that of the second insulating block.

18. The protective device as in claim 1, wherein the first direction is perpendicular to a direction of current flow in the metal element, and a length of the bridge element in the first direction is longer than a length of the metal element in the first direction.

19. The protective device as in claim 1, wherein the intermediate support is an extension of a third electrode that is coupled to a heat-generating element and spaced apart from the first and second electrodes.

20. The protective device as in claim 19, wherein two opposite ends of the bridge element in the first direction are in direct contact with the intermediate support.

21. The protective device as in claim 1, further comprising an auxiliary medium, wherein

the intermediate support is located between the first electrode and the second electrode, and

the auxiliary medium is located entirely below the metal element, located between the intermediate support and the first electrode, and located between the intermediate support and the second electrode.

22. The protective device as in claim 21, wherein the auxiliary medium is in physical contact with the first electrode, the second electrode and the intermediate support.