Over-voltage protection circuit

• US 20060152873A1
• Filed: 03/09/2006
• Published: 07/13/2006
• Est. Priority Date: 10/01/2001
• Status: Abandoned Application

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Inventors: Mathew, Roshy Stan, Luong, Quang A., Madter, Richard C., Shiner, Andrew D., Schaaff, Carl D., Habicher, Michael F.
• Application Number:
  US11/371,686
• Publication Number:
  US 20060152873A1
• Time in Patent Office: Days
• US Class Current: 361/91.100
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence

Abstract

An over-voltage protection circuit is disclosed herein for protection against over-voltage of an energy storage device while charging. The circuit operates within the operational limits of a battery-operated device, such as a mobile or handheld device. The over-voltage protection circuit comprises an over-voltage protection device, and an over-voltage protection controller. The controller allows current to flow to the over-voltage protection device only when an energy storage device is experiencing over-voltage. In allowing current to flow to the over-voltage protection device only when the voltage across the energy storage device is above a predetermined voltage, power conservation is achieved

Claims

1. An over-voltage protection circuit for connection to a charging circuit for maintaining a voltage across an energy storage device at or below a predetermined voltage during charging, comprising:

an over-voltage protection device; and

an over-voltage protection controller for connecting said over-voltage protection device in parallel with said energy storage device only when the voltage across the energy storage device exceeds said predetermined voltage, so as to draw excess charge from said energy storage device.

2. An over-voltage protection circuit according to claim 1 wherein said over-voltage protection controller comprises a switch actuated in response to an over-voltage condition at said energy storage device.

3. An over-voltage protection circuit according to claim 2 wherein said over-voltage protection controller further comprises an over-voltage detector coupled to said energy storage device and to said switch, which causes the switch to be actuated when a voltage measured across said energy storage device exceeds said predetermined voltage.

4. An over-voltage protection circuit according to claim 3 wherein said over-voltage detector and said switch are integral with one another.

5. An over-voltage protection circuit according to claim 1 wherein said over-voltage protection device dissipates excess charge drawn from the energy storage device.

6. An over-voltage protection circuit according to claim 1 wherein said over-voltage protection controller comprises a zener diode.

7. An over-voltage protection circuit according to claim 6 wherein said over-voltage protection controller further comprises a switch connected to the zener diode, which is closed during charging and open otherwise.

8. An over-voltage protection circuit according to claim 1 wherein said over-voltage protection device comprises a resistor.

9. An over-voltage protection circuit according to claim 6 wherein said over-voltage protection controller and said over-voltage protection device are integral with one another.

10. An over-voltage protection circuit according to claim 1 wherein said over-voltage protection circuit comprises a zener diode connected in series with a resistor.

11. An over-voltage protection circuit according to claim 1 wherein said over-voltage protection controller comprises a shunt regulator.

12. An over-voltage protection circuit according to claim 11 wherein said over-voltage protection device comprises a resistor connected in series with said shunt regulator.

13. An over-voltage protection circuit according to claim 1 wherein said over-voltage protection device temporarily stores excess charge drawn from the energy storage device.

14. An over-voltage protection circuit according to claim 13 wherein said over-voltage protection controller further comprises a dissipation controller for dissipating the excess charge stored in said over-voltage protection device.

15. An over-voltage protection circuit according to claim 14 wherein said dissipation controller comprises a dissipation switch that connects said over-voltage protection device to ground in order to dissipate the stored voltage.

16. An over-voltage protection circuit according to claim 15 wherein said dissipation controller comprises a dissipation control mechanism that actuates said dissipation switch so as to connect and disconnect the over-voltage protection device from said dissipation controller.

17. An over-voltage protection circuit according to claim 1 wherein said over-voltage protection device comprises a capacitor.

18. An over-voltage protection circuit according to claim 17 wherein said energy storage device comprises first and second energy storage components and wherein said over-voltage protection controller comprises first and second switches coupled to said first and second energy storage components, respectively, and connected in series to either end of the capacitor.

19. An over-voltage protection circuit according to claim 18 wherein said switches are actuated, during over-voltage, so as to connect or disconnect the capacitor to each energy storage component in order to balance charge between them.

20. An over-voltage protection circuit according to claim 18 wherein said over-voltage protection controller further comprises an actuating means that actuates the connection or disconnection of the capacitor to each energy storage component at a regular time interval.

21. An over-voltage protection circuit according to claim 18 wherein said over-voltage protection controller further comprises an over-voltage detector coupled to said first and second energy storage components.

22. An over-voltage protection circuit according to claim 21 wherein said over-voltage detector controls actuation of said switches.

23. An over-voltage protection circuit according to claim 1 wherein said over-voltage protection device comprises an inductor.

24. An over-voltage protection circuit according to claim 23 wherein said energy storage device comprises first and second energy storage components and wherein said over-voltage protection controller comprises first and second switches coupled to said first and second energy storage components, respectively, and connected in series with the inductor with respect to said charging circuit.

25. An over-voltage protection circuit according to claim 24 wherein said over-voltage protection controller further comprises first and second diodes connected in parallel with said first and second switches, respectively.

26. An over-voltage protection circuit according to claim 24 wherein said switches are actuated, during over-voltage, to connect or disconnect the inductor to each energy storage component in order to balance charge between them.

27. An over-voltage protection circuit according to claim 24 wherein said over-voltage protection controller further comprises an actuating means that actuates the connection and disconnection of the inductor to each energy storage component at a regular time interval.

28. An over-voltage protection circuit according to claim 25 wherein said over-voltage protection controller further comprises an over-voltage detector coupled to said first and second energy storage components.

29. An over-voltage protection circuit according to claim 28 wherein said over-voltage detector controls actuation of said switches.

30. An over-voltage protection circuit for connection to a charging circuit for use with a handheld device for maintaining a voltage across an energy storage device at or below a predetermined voltage so as to avoid over-voltage during charging, comprising:

an over-voltage protection device; and

an over-voltage protection controller for connecting said over-voltage protection device in parallel with said energy storage device in response to an over-voltage condition at the energy storage device, so as to draw excess charge from said energy storage device,

wherein said over-voltage protection circuit is connected to charging leads which are connected to the charging circuit.

31. An over-voltage protection circuit according to claim 30 wherein the over-voltage protection circuit operates within the operational limits of the handheld device.