OVER-VOLTAGE PROTECTION

• US 20110134577A1
• Filed: 12/04/2009
• Published: 06/09/2011
• Est. Priority Date: 12/04/2009
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Mobile Communications AB (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Inventors: Skarp, Carl Filip Erik
• Granted Patent: US 8,462,478 B2
• Time in Patent Office: Days
• US Class Current: 361/91.2
• CPC Class Codes: H01H 57/00 Electrostrictive relays; Piezoelectric relays
• CPC Class Codes: H01H 79/00 Protective switches in which excess current causes the closing of contacts, e.g. for short-circuiting the apparatus to be protected H01H39/004 takes precedence
• CPC Class Codes: H02H 9/042 comprising means to limit the absorbed power or indicate damaged over-voltage protection device

Abstract

A device may include a switch and a circuit coupled to the switch. The switch may include a structure with a top portion and a bottom portion and a material included within the structure. The material is configured to expand within the structure when voltage is applied to the material. The switch may also include a conductive element located in a bottom portion of the structure and connected to the material, wherein the conductive element operates to electrically close the switch when the applied voltage exceeds a threshold. The circuit includes a resistor. The circuit is configured to reduce the voltage supplied to components of the device when the switch is closed.

Claims

1. A device, comprising:

a switch comprising;

a structure including a top portion and a bottom portion,

a material included within the structure, wherein the material is configured to expand within the structure when voltage is applied to the material, and

a conductive element located in a bottom portion of the structure and connected to the material, wherein the conductive element operates to electrically close the switch when the applied voltage exceeds a threshold; and

a circuit coupled to the switch, wherein the circuit includes a resistor, and the circuit is configured to reduce the voltage supplied to components of the device when the switch is closed.

2. The device of claim 1, wherein the material comprises an electroactive polymer (EAP).

3. The device of claim 2, wherein the conductive element comprises a metallic disk that is configured to move within the structure as the EAP expands.

4. The device of claim 1, wherein the structure comprises a cylindrical structure.

5. The device of claim 1, wherein the resistor provides a controlled voltage drop associated with an over-voltage condition when the switch is closed.

6. The device of claim 1, wherein the switch further comprises:

a connector, and wherein the conductive element is configured to electrically contact the connector when the applied voltage exceeds the threshold.

7. The device of claim 6, wherein the switch is further configured to open when the applied voltage is less than the threshold.

8. The device of claim 7, wherein when the applied voltage is less than the threshold, the conductive element is configured to move within the cylinder such that it does not contact the connector and the switch opens.

9. The device of claim 1, wherein the device comprises a mobile telephone.

10. A method, comprising:

receiving, by a switch that includes an electroactive polymer (EAP) material, a voltage;

closing the switch when the voltage exceeds a threshold;

reducing voltage applied to components of a device when the switch is closed; and

opening the switch when the received voltage is below the threshold.

11. The method of claim 10, wherein the switch comprises a structure configured to house the EAP material, a conductive disk located adjacent a portion of the EAP material, and an electrical connector, wherein closing the switch comprises:

moving the conductive disk in a first direction within the structure when the voltage exceeds the threshold such that the conductive disk electrically contacts the electrical connector.

12. The method of claim 11, wherein opening the switch comprises:

moving the conductive disk in a second direction within the structure when the voltage is below the threshold such that the conductive disk does not electrically contact the electrical connector.

13. The method of claim 12, wherein the moving the conductive disk in a first direction and a second direction is performed based on expansion and contraction, respectively, of the EAP material.

14. A device, comprising:

a switch comprising;

an electroactive polymer (EAP) material, and

a conductive element located adjacent the EAP material, wherein the conductive element is configured to move when the EAP material expands and to electrically close the switch when a voltage applied to the EAP material exceeds a threshold.

15. The device of claim 14, further comprising:

a resistor coupled to the switch, wherein the resistor and switch are configured to reduce the voltage supplied to components of the device when the switch is closed.

16. The device of claim 14, wherein the switch is further configured to open or remain open when the voltage applied to the EAP material is less than the threshold.

17. The device of claim 14, wherein the switch further comprises an electrical connector configured to electrically contact the conductive element when the voltage applied to the EAP material exceeds the threshold.

18. The device of claim 14, further comprising:

a plurality of components;

a power source connected to the switch, the power source being configured to supply voltage to the EAP material; and

a resistor coupled to the switch, wherein the switch and the resistor are connected in parallel with the power source, and when voltage from the power source exceeds the threshold, the resistor is configured to reduce voltage supplied from the power source to at least one of the plurality of components.

19. The device of claim 14, wherein the device comprises an electronic device.

20. The device of claim 14, wherein the device comprises a power distribution device.