Electrical devices having a polymer PTC array

• US 6,282,072 B1
• Filed: 02/23/1999
• Issued: 08/28/2001
• Est. Priority Date: 02/24/1998
• Status: Expired due to Fees

• Current Assignee: Littelfuse Incorporated
• Original Assignee: Littelfuse Incorporated
• Inventors: Nguyen, Thinh K., Minervini, Anthony D.
• Primary Examiner(s): Jackson, Stephen W.
• Application Number:
  US09/256,605
• Time in Patent Office: 917 Days
• Field of Search: 361/103, 361/104, 361/106, 361/93.1, 361/58, 361/115
• US Class Current: 361/103
• CPC Class Codes: H01C 1/1406 Terminals or electrodes formed on resistive elements having positive temperature coefficient
• CPC Class Codes: H01C 13/02 Structural combinations of resistors impedance networks per se H03H

Abstract

The present invention is an electrical circuit protection device having a PTC element with a first common electrode affixed to a first surface of the PTC element and at least two second electrodes affixed to a second surface of the PTC element. The at least two second electrodes are physically separated from one another such that when the at least two second electrodes are connected to a source of electrical current, the current travels from the at least two second electrodes, respectively, through the PTC element, to the first common electrode.

Claims

1. An electrical circuit protection device comprising:

a PTC element having first and second surfaces;

a first common electrode affixed to the first surface of the PTC element;

a second electrode affixed to the second surface of the PTC element;

a third electrode affixed to the second surface of the PTC element and being physically separated from the second electrode so that when the second and third electrodes are connected to a source of electrical current, the current travels from the second and third electrodes, respectively, through the PTC element, to the first common electrode.

2. The circuit protection device of claim 1, further including a plurality of electrodes affixed to the second surface of the PTC element, the plurality of electrodes being physically separated from one another so that when the plurality of electrodes are connected to a source of electrical current, the current travels from the plurality of electrodes, respectively, through the PTC element, to the first common electrode.

3. The circuit protection device of claim 1, wherein the first, second and third electrodes each include a collection portion and a connection portion.

4. The circuit protection device of claim 3, wherein an electrically insulating substrate is connected to the PTC element and is positioned between the connection portions of the first and the second and third electrodes, respectively.

5. The circuit protection device of claim 1, wherein the PTC element is comprised of a conductive polymer.

6. The circuit protection device of claim 1, wherein the first, second and third electrodes are comprised of a metal foil.

7. The circuit protection device of claim 1, wherein the PTC element is encapsulated in a protective housing.

8. An electrical apparatus for providing overcurrent protection to a plurality of electrical circuits, the apparatus comprising:

a single continuous PTC element having a first and a second surface;

a first electrically insulating substrate connected to the PTC element;

a common first electrode having a connection portion and a collection portion, the connection portion being in contact with the insulating substrate and the collection portion being in contact with the first surface of the PTC element; and

a plurality of second electrodes having a connection portion and a collection portion, the connection portion of each of the plurality of electrodes being in contact with the insulating substrate and the collection portion of each of the plurality of electrodes being in contact with the second surface of the PTC element.

9. The electrical apparatus of claim 8, wherein the plurality of second electrodes are separated from one another so that when each of the plurality of second electrodes is electrically connected to a corresponding plurality of electrical circuits having electrical current flowing therethrough, the current from each circuit flows through the single continuous PTC element to the first common electrode.

10. The electrical apparatus of claim 8, wherein the apparatus is in the form a laminar sheet.

11. The electrical apparatus of claim 8, further including a second electrically insulating substrate connected to the PTC element.

12. The electrical apparatus of claim 10, wherein the laminar sheet has a thickness of less than 0.020 inch.

13. The electrical apparatus of claim 8, further including a protective coating covering the PTC element.

14. The electrical apparatus of claim 8, wherein the electrically insulating substrate is comprised of epoxy.

15. The electrical apparatus of claim 8, wherein the electrically insulating substrate is comprised of a polyimide resin.

16. An electrical apparatus comprised of:

a first PTC element having a first and a second surface, a first plurality of electrodes affixed to the first surface and a common electrode affixed to the second surface; and

a second PTC element having a first and a second surface, a second plurality of electrodes affixed to the first surface of the second PTC element and the common electrode affixed to the second surface of the second PTC element.