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.

TECHNICAL FIELD OF THE INVENTION

The invention relates generally to over-voltage protection and, more particularly, to controlled over-voltage protection.

DESCRIPTION OF RELATED ART

Electronic devices, such as communication devices, lap top computers, personal computers etc., have become increasingly important in every day life. As a result, protecting these devices from voltage spikes or other voltage/current-related problems is very important to users from both a reliability perspective and a safety perspective.

In typical devices, a fuse may be used to protect components from an over-voltage condition. One drawback with using fuses is that after the over-voltage condition occurs, the fuse may require replacement or manual handling to return the device back to working condition. Replacement and/or handling of fuses is time consuming and difficult for many users.

SUMMARY

According to a first aspect, a device comprising a switch and a circuit is provided. The switch includes a structure that has a top portion and a bottom portion and a material included within the structure, wherein the material is configured to expand within the structure when voltage is applied to the material. The structure also includes 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 is 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.

Additionally, the material may comprise an electroactive polymer (EAP).

Additionally, the conductive element may comprise a metallic disk that is configured to move within the structure as the EAP expands.

Additionally, the structure may comprise a cylindrical structure.

Additionally, the resistor provides a controlled voltage drop associated with an over-voltage condition when the switch is closed.

Additionally, the switch may further comprise a connector, and wherein the conductive element is configured to electrically contact the connector when the applied voltage exceeds the threshold.

Additionally, the switch may be further configured to open when the applied voltage is less than the threshold.

Additionally, when the applied voltage is less than the threshold, the conductive element may be configured to move within the cylinder such that it does not contact the connector and the switch opens.

Additionally, the device may comprise a mobile telephone.

According to another aspect, a method is provided. The method includes receiving, by a switch that includes an electroactive polymer (EAP) material, a voltage and closing the switch when the voltage exceeds a threshold. The method also includes 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.

Additionally, the switch may comprise a structure configured to house the EAP material, a conductive disk located adjacent a portion of the EAP material, and an electrical connector, and closing the switch may comprise 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.

Additionally, opening the switch may comprise 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.

Additionally, moving the conductive disk in a first direction and a second direction may be performed based on expansion and contraction, respectively, of the EAP material.

According to still another aspect, a device includes a switch. The switch includes 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.

Additionally, the device may further comprise 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.

Additionally, the switch may be further configured to open or remain open when the voltage applied to the EAP material is less than the threshold.

Additionally, the switch may further comprise an electrical connector configured to electrically contact the conductive element when the voltage applied to the EAP material exceeds the threshold.

Additionally, the device may further comprise a plurality of components and a power source connected to the switch, the power source being configured to supply voltage to the EAP material. The device may further comprise 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.

Additionally, the device may comprise an electronic device.

Additionally, the device may comprise a power distribution device.

DETAILED DESCRIPTION

Exemplary System

FIG. 1is a diagram of an exemplary user device100which may be used in conjunction with devices, systems and methods described herein. In an exemplary implementation, user device100may be a mobile terminal. As used herein, the term “mobile terminal” may include a cellular radiotelephone with or without a multi-line display; a Personal Communications System (PCS) terminal that may combine a cellular radiotelephone with data processing, facsimile and data communications capabilities; a personal digital assistant (PDA) that can include a radiotelephone, pager, Internet/Intranet access, Web browser, organizer, calendar and/or a global positioning system (GPS) receiver; and a conventional laptop and/or palmtop receiver or other appliance that includes a radiotelephone transceiver. Mobile terminals may also be referred to as “pervasive computing” devices.

Referring toFIG. 1, user device100may include housing110, speaker120, display130, control buttons140, keypad150, microphone160and connector170. It should be understood that user device100may include other and/or different components. For example, user device100may include a camera and a flash mechanism used to take pictures and/or videos.

Housing110may protect the components of user device100from outside elements. Speaker120may provide audible information to a user of user device100. Display130may provide visual information to the user. For example, display130may provide information regarding incoming or outgoing telephone calls and/or incoming or outgoing electronic mail (e-mail), instant messages, short message service (SMS) messages, etc. Control buttons140may permit the user to interact with user device100to cause user device100to perform one or more operations, such as place a telephone call, play various media, take a picture, etc.

For example, control buttons140may include a dial button, hang up button, play button, a shutter button, etc. Keypad150may include a standard telephone keypad. Microphone160may receive audible information from the user. Connector170may be a connector or interface used for charging user device100. In an exemplary implementation, connector170may be accessible from the exterior of user device100.

Aspects of the invention are described herein in the context of protecting a portable device, such as user device100, from an over-voltage condition. It should also be understood that devices, systems and methods described herein may also be used with other types of devices, such as a personal computer (PC), a laptop computer, a PDA, a media playing device (e.g., an MPEG audio layer 3 (MP3) player, a video game playing device), or other device that may not include various communication functionality for communicating with other devices. Still further, devices, systems and methods described herein may be used in medium or high voltage applications, such as in power transformers.

FIG. 2is a diagram illustrating components of user device100according to an exemplary implementation. User device100may include bus210, processor220, memory230, input device240, output device250, power supply260, communication interface270and over-voltage protector280. Bus210permits communication among the components of user device100. One skilled in the art would recognize that user device100may be configured in a number of other ways and may include other or different elements. For example, user device100may include one or more modulators, demodulators, encoders, decoders, etc., for processing data.

Processor220may include a processor, microprocessor, an application specific integrated circuit (ASIC), field programmable gate array (FPGA) or other processing logic. Processor220may execute software instructions/programs or data structures to control operation of user device100.

Memory230may include a random access memory (RAM) or another type of dynamic storage device that stores information and instructions for execution by processor220; a read only memory (ROM) or another type of static storage device that stores static information and instructions for use by processor220; a flash memory (e.g., an electrically erasable programmable read only memory (EEPROM)) device for storing information and instructions; and/or some other type of magnetic or optical recording medium and its corresponding drive. Memory230may also be used to store temporary variables or other intermediate information during execution of instructions by processor220. Instructions used by processor220may also, or alternatively, be stored in another type of computer-readable medium accessible by processor220. A computer-readable medium may include one or more memory devices.

Input device240may include mechanisms that permit an operator to input information to user device100, such as microphone160, keypad150, control buttons140, a keyboard (e.g., a QWERTY keyboard, a Dvorak keyboard), a gesture-based device, an OCR based device, a joystick, a virtual keyboard, a speech-to-text engine, a mouse, a pen, voice recognition and/or biometric mechanisms, etc.

Output device250may include one or more mechanisms that output information to the user, including a display, such as display130, a printer, one or more speakers, such as speaker120, etc. Power supply260, also referred to herein as battery260, may include one or more batteries or other power source components used to supply power to components of user device100.

Communication interface270may include one or more transceivers that enable user device100to communicate with other devices via wired, wireless or optical mechanisms. For example, communication interface270may include one or more radio frequency (RF) transmitters, receivers and/or transceivers and one or more antennas for transmitting and receiving RF data. Communication interface270may also include a modem or an Ethernet interface to a local area network (LAN) for communicating via a network.

Over-voltage protector280may include components to protect user device100from an over-voltage condition, such as a voltage spike. In an exemplary implementation, over-voltage protector280may use materials that change their physical dimensions when placed in an electric field or when voltage is applied. For example, over-voltage protector280may use an electroactive polymer (EAP) material that expands when voltage is applied, as described in more detail below. In some implementations, over-voltage protector280may include circuitry that allows for a controlled reduction of voltage associated with an over-voltage condition, as described in detail below.

User device100may provide a platform for a user to make and receive telephone calls, send and receive messages (e.g., electronic mail, text messages, multi-media messages, SMS messages, etc.), play music, play games, take pictures/videos and execute various other applications. User device100, as described in detail below, may also perform processing associated with protecting user device100from an over-voltage condition. In an exemplary implementation, user device100may perform all or some of these operations in response to processor220executing sequences of instructions contained in a computer-readable medium, such as memory230. Such instructions may be read into memory230from another computer-readable medium via, for example, communication interface270. A computer-readable medium may include one or more memory devices. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement processes consistent with the invention. Thus, implementations described herein are not limited to any specific combination of hardware circuitry and software.

FIG. 3is a diagram illustrating components of over-voltage protector280according to an exemplary implementation. Referring toFIG. 3, over-voltage protector280may include structure310, EAP material320and conductive disk330. The configuration illustrated inFIG. 3is provided for simplicity. In other implementations, over-voltage protector280may include additional elements, such as electrical circuitry used to provide controlled protection from an over-voltage condition, as described in detail below.

Structure310may include a structural component used to house EAP material320. InFIG. 3, structure310is illustrated as being cylindrical in shape. It should be understood that in alternative implementations, structure310may have other shapes (e.g., cuboid, ovoid, etc.). The top portion of structure310(also referred to herein as cylinder310) labeled312may include an electrically insulating material.

EAP material320, as discussed above, may include a material that changes physical dimensions and/or shape when placed in an electric field or when voltage is applied. For example, in an exemplary implementation, EAP material320may include a dielectric EAP material or an ionic EAP material that expands axially within cylinder310when voltage is applied to the top portion of EAP material320, labeled322inFIG. 3.

Conductive disk330may include a metallic disk that connects to the bottom side of EAP material320, as illustrated inFIG. 3. As EAP material320expands, conductive disk330moves within cylinder310. For example, conductive disk330may slide within cylinder310as EAP material320expands. The expansion of EAP material320and movement of conductive disk320may be used to close an over-voltage protection switch, as described in more detail below.

In some implementations, a length or depth of structure310may be significantly different from a width or height of structure310based on, for example, the voltage levels being monitored by over-voltage protector280, as well as voltage levels expected during an over-voltage condition. For example, in some implementations the width and/or depth of structure310may be much less than the length of structure310. In addition, in implementations in which over-voltage protector280is monitoring relatively low voltages, the length of structure310may be relatively short (e.g., less than one centimeter) and the length/distance of the gap (e.g., air gap) between conductive disk330and the bottom of structure310may also be small. In implementations in which high voltage levels are being monitored, the length of structure310may be relatively long (e.g., several centimeters or more) and the length/distance of the gap between conductive disk330and the bottom of structure310may also be relatively long.

In addition, the distance or gap between conductive disk330and the bottom of cylinder320may vary based on the particular voltages and/or device being monitored. For example, in situations in which the normal variations in voltages are fairly large and the components of the device being protected (e.g., user device100) allow for a fairly wide range of voltages, the distance between conductive disk330and the bottom of cylinder320during normal operating conditions (e.g., normal voltage condition) may be relatively large to allow for greater expansion of EAP material320without closing an over-voltage protection switch. However, in situations in which the components of the device being protected are particular sensitive to voltage fluctuations (which may result in damage to the components), the distance between conductive disk330and the bottom of cylinder310during normal operating conditions may be relatively small to ensure that the components of the device are adequately protected.

The configuration of over-voltage protector280inFIG. 3is exemplary only. For example, as described above, in other implementations, structure310may have other shapes. In addition, other materials that expand when voltage is applied may be used in place of or in combination with EAP material320in other implementations.

FIG. 4Ais a cross-section of the portion of over-voltage protector280ofFIG. 3. Referring toFIG. 4A, over-voltage protector280may include an over-voltage protection switch (OVPS)400that includes cylinder310, EAP material320, conductive disk330and connector410. OVPS400may be used in connection with an electrical circuit to control over-voltage conditions, as described in detail below. As illustrated inFIG. 4A, EAP material320may be contained in an upper portion of cylinder310when user device100is in a normal operating condition. That is, when a normal operating voltage associated with operation of user device100is applied to EAP material320, EAP material320may be contained within the upper portion of cylinder310and conductive disk330may not contact connector410.

In an exemplary implementation, conductive disk330electrically contacts the sides of cylinder310, as illustrated inFIG. 4A. This may allow cylinder310to act as one pole of a connection for OVPS400. When voltage above a threshold voltage is applied to EAP material320, EAP material320may expand within cylinder310such that conductive disk330may contact connector410, as illustrated inFIG. 4B. When conductive disk330contacts connector420, this may effectively close OVPS400to protect components of user device100, as described in more detail below.

As described above, OVPS400may be used in conjunction with circuitry that permits over-voltage protector280to control an over-voltage condition without shutting down user device100. For example,FIG. 5Aillustrates an exemplary circuit500that includes OVPS400. Referring toFIG. 5A, circuit500may include a direct current (DC) to DC (DC-DC) converter that is used in device100to provide power to components of user device100. The DC-DC converter may include voltage source510, inductor520, transistor530, diode540, and capacitor560. Circuit500may also include OVPS400and resistor550. In an exemplary implementation, OVPS440and resistor550may be included in over-voltage protector280and may be connected in parallel with voltage source510to reduce voltage supplied by voltage source510when an over-voltage condition occurs, as described in more detail below.

Voltage source510may represent a voltage or power source, such as a DC voltage source, within user device100that may be monitored for an over-voltage condition by OVPS400. Voltage source510may be associated with powering components of user device100. As an example, voltage source510may be located in series with power supply260and voltage source510may represent the primary power source associated with powering user device100. In each case, voltage source510may represent a voltage generated within user device100that may be monitored for an over-voltage condition.

Transistor530may be connected between a ground point and a point coupled to an output of inductor520and an input of diode540. Transistor530may be used to drive current through inductor520when transistor530is closed, thereby increasing the voltage across capacitor560when transistor530is open. Inductor520may be designed to filter out specific frequencies from the direct current output of voltage source510from being transmitted to other devices in circuit500. Diode540may be designed to protect components located upstream of diode540from reverse currents generated in the DC-DC converter. Capacitor560may be connected to an output of diode540and in parallel with OVPS400. The voltage across capacitor560may represent the output voltage of the DC-DC converter circuit. This output voltage may be used to power some or all of the components of user device100.

In an exemplary implementation, OVPS400may be connected to the output of diode540. Resistor550may be connected in series with OVPS400, such that OVPS400and resistor550are connected in parallel with voltage source510. OVPS400may monitor the voltage to detect an over-voltage condition and to control the over-voltage condition without necessarily shutting down operation of user device100. For example, the output voltage produced across capacitor560may be reduced via OVPS400and resistor550, thereby allowing an over-voltage condition to be handled in a controlled manner, as described in more detail below.

FIG. 5Bis a detailed diagram of components of OVPS400connected to components of circuit500according to an exemplary implementation. As illustrated, connector410of OVPS400may be electrically connected to resistor550and the side of cylinder310of OVPS400may be connected to the other leg of resistor550through capacitor560. When the connection is completed (e.g., conductive disk330contacts connector410), resistor550is connected in parallel with voltage source510. Resistor550is also connected in parallel with elements that over-voltage protector280is attempting to protect. Resistor550may act to reduce or discharge the over-voltage condition, as described in detail below.

FIG. 6is a flow diagram illustrating exemplary processing associated with controlling an over-voltage condition with respect to user device100. Processing may begin with user device100being powered up or being charged. For example, assume that user device100is turned on and a user is interacting with user device100to access the Internet, place a telephone call, take a picture, etc. In such a condition, over-voltage protector280may receive a voltage (act610).

For example, assume that voltage source510inFIG. 5Acorresponds to the normal operating voltage associated with user device100. As also illustrated inFIG. 5A, OVPS400may be electrically coupled to voltage source510via inductor520and diode540. As described above with respect toFIGS. 4A and 4B, when voltage is applied to OVPS400, EAP material320within OVPS400may expand within cylinder310(act620). During normal operating conditions, EAP material320may expand to the level illustrated inFIG. 4A. That is, the EAP material320may not expand such that conductive disk330makes electrical contact with connector410.

Over-voltage protector280may determine whether an over-voltage condition occurs (act630). If not (act630—no), processing may return to act610. That is, over-voltage protector280may continue to receive a voltage from voltage source510and EAP material320may expand/contract based on the applied voltage. However, if an over-voltage condition occurs (act630—yes), EAP material320may expand within cylinder310and conductive disk330may electrically contact connector410. OVPS400may close and circuit500may control the over-voltage condition (act640). For example, with OVPS400closed, current may flow through resistor550to a ground. The resulting output voltage at capacitor/load560may be reduced. In this manner, circuit500allows for a controlled voltage drop when an over-voltage condition occurs, as opposed to a conventional fuse that causes a hard short to ground when an over-voltage condition occurs. That is, connecting OVPS400and resistor550in parallel with voltage source510and in parallel with components that over-voltage protector280is designed to protect, the output voltage of the DC-DC converter is reduced to a level that may be acceptable to components of user device100.

Continuing with this example, over-voltage protector280may continue to monitor the voltage via OVPS400. If the over-voltage condition is not corrected (act650—no), OVPS400remains closed and circuit500continues to control the over-voltage condition. If, however, the over-voltage condition is corrected (act650—yes), OVPS400opens (act660). In this situation, resistor550is effectively disconnected from circuit500and user device100resumes normal operations (act660). That is, when the voltage applied to EAP material320is reduced to the normal level, EAP material320may contract and conductive disk330will move in the opposite direction (e.g., away from connector410) such that conductive disk330does not electrically contact connector410. OVPS400may then open, thereby effectively disconnecting resistor550from circuit500.

In this manner, over-voltage protector280may monitor voltage within user device and provide for a controlled reduction in voltage when an over-voltage condition exists. In addition, when the over-voltage condition ends and normal operating voltages exist, over-voltage protector280returns user device100to the normal operating mode without the user having to perform any resetting or replacing of a fuse or other over-voltage protector.

CONCLUSION

Implementations described herein provide for controlled over-voltage protection using a material that expands based on an applied voltage. In addition, when the over-voltage condition no longer exists, the device being protected automatically returns to normal operating conditions without requiring any manual intervention by the user.

For example, aspects described herein refer to providing protection to one or more components of user device100. It should be understood that over-voltage protector280may be configured to protect all components of user device100or some components of user device100based on the particular configuration. For example, over-voltage protector280may be connected in parallel with the main power source of user device100to protect all components of user device100that receive power from the main power source. Alternatively, over-voltage protector280may be connected in parallel with a particular element or elements to protect those elements. As an example, a camera and/or camera flash component (e.g., a xenon flash) may be protected from an over-voltage condition by connecting over-voltage protector280in parallel with the camera/flash.

In addition, aspects have been described above with respect to using over-voltage protector280within an electronic device (e.g., user device100). In other implementations, over-voltage protector280may be used in industrial or power-related scenarios to protect equipment and provide controlled voltage protection. For example, over-voltage protector280may be used in connection with power distribution equipment, such as transformers or other medium/high power devices and/or power connectors. In such scenarios, the size of structure310and the amount of EAP material may be designed based on the particular voltages/ranges of expected voltages. That is, the gap (e.g., air gap) provided between conductive disk330and an electrical connector (e.g., connector410) when the over-voltage condition does not exist may be sized to provide adequate distance/separation to prevent an inadvertent short circuiting and closing of the over-voltage protection switch.

Still further, implementations described above illustrate OVPS400connected in series with resistor550to control the voltage output by a power source. The particular value of resistor550may be based on the particular voltages being monitored and the voltages expected with the over-voltage condition. In addition, a single resistor550is described above as being connected to OVPS400. It should be understood that any resistive element or combination of elements may be used.

In addition, aspects have been described above with respect to using EAP material and an exemplary circuit used in conjunction with the EAP material. In other implementations, other materials that expand and/or other circuitry may be used to provide controlled over-voltage protection. In addition, aspects have been described above with respect to using an over-voltage protection switch in conjunction with a control circuit that will reduce voltages applied to components of the device. In other implementations, the over-voltage protection switch described above may be used to cut power to a device when an over-voltage protection condition exists. That is, the over-voltage protection switch may be used without use of the control circuit.

Further, while series of acts have been described with respect toFIG. 6, the order of the acts may be varied in other implementations consistent with the invention. Moreover, non-dependent acts may be performed in parallel.

It will also be apparent to one of ordinary skill in the art that aspects of the invention, as described above, may be implemented in, for example, charging cables, computer devices, cellular communication devices/systems, media playing devices, methods, and/or computer program products. Accordingly, aspects of the present invention may be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.). Furthermore, aspects of the invention may take the form of a computer program product on a computer-usable or computer-readable storage medium having computer-usable or computer-readable program code embodied in the medium for use by or in connection with an instruction execution system. The actual software code or specialized control hardware used to implement aspects consistent with the principles of the invention is not limiting of the invention. Thus, the operation and behavior of the aspects were described without reference to the specific software code—it being understood that one of ordinary skill in the art would be able to design software and control hardware to implement the aspects based on the description herein.

Further, certain portions of the invention may be implemented as “logic” that performs one or more functions. This logic may include hardware, such as a processor, a microprocessor, an ASIC, or an FPGA, software, or a combination of hardware and software.