Energy source monitoring and control system

• US 7,580,803 B2
• Filed: 05/01/2007
• Issued: 08/25/2009
• Est. Priority Date: 09/06/2006
• Status: Active Grant

• Current Assignee: Eastway Fair Company Limited
• Original Assignee: Techtronic Power Tools Technology Limited (Techtronic Industries Company Limited)
• Inventors: Soultanian, Daniel S., Hornick, George Michael, Minalga, Philip F.
• Primary Examiner(s): Nghiem; Michael P
• Application Number:
  US11/799,337
• Publication Number:
  US 20080059000A1
• Time in Patent Office: 847 Days
• Field of Search: 702/64, 702/60, 702/61, 702/63, 702/65, 320/134, 320/136
• US Class Current: 702/64
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

An energy source monitoring system evaluates the state of an energy source and responsively controls a power tool or other device. The energy source may be a power tool battery pack that includes multiple individual battery packs connected in series. The energy source monitoring system may be incorporated into a power tool, screwdriver, flashlight, audio and/or video player, or any other device. The energy source monitoring system intelligently exercises control over the power applied to the device. In one implementation, the energy source monitoring system detects when voltages in the energy source have fallen below a cutoff level, yet allows the device to continue running until the operator finishes the current device operation.

Claims

1. A power supply monitoring and control system for a power supply operated device, the system comprising:

a first voltage measurement point;

a second voltage measurement point;

voltage measurement logic coupled to the voltage measurement points and which determines a power supply voltage V1 and a power supply voltage V2 arranged in series with the power supply voltage V1;

a power switch operable to connect the series arranged power supply voltages V1 and V2 to device circuitry;

a function switch to activate a function of the device circuitry;

comparison logic in communication with the voltage measurement logic, the comparison logic operable to recognize a cutoff condition when V1, V2, or both V1 and V2 fade below a cutoff threshold for disconnecting V1 and V2 from the device circuitry; and

switch control logic in communication with the comparison logic, the switch control logic operable to hold the power switch in an ‘

ON’

state until the function is complete despite recognition of the cutoff condition, then release the power switch to an ‘

OFF’

state.

2. The power supply monitoring and control system of claim 1, where the power switch is a dropout switch.

3. The power supply monitoring and control system of claim 2, further comprising a switch state control input coupled to the dropout switch and to the switch control logic.

4. The power supply monitoring and control system of claim 1, further comprising an operational indicator which illuminates when both V1 and V2 exceed an operation threshold.

5. The power supply monitoring and control system of claim 1, further comprising a warning indicator which illuminates when V1, V2, or both V1 and V2 fall below a fading threshold.

6. The power supply monitoring and control system of claim 1, further comprising a cutoff indicator which illuminates in response to the cutoff condition.

7. The power supply monitoring and control system of claim 1, where the switch control logic is further operable to prevent reconnection of V1 and V2 for restart of the function until V1 and V2 rise above an operation threshold for allowing the function to start.

8. The power supply monitoring and control system of claim 1, where the cutoff threshold comprises a predetermined percentage of a nominal energy source voltage for disconnecting the voltages V1 and V2 from the device circuitry.

9. The power supply monitoring and control system of claim 1, where the voltage measurement logic comprises a first voltage divider across both V1 and V2 in series and a second voltage divider across V2.

10. A power supply monitoring and control system for a power supply operated device, the system comprising:

a power supply input for accepting series connected power supply voltages V1 and V2;

a main power switch coupled between the power supply input and device circuitry;

a function switch for activating a function of the device circuitry;

a controller coupled to the power supply input and the main power switch;

a memory coupled to the controller, the memory comprising;

a cutoff threshold for disconnecting the series connected power supply voltages V1 and V2 for stopping device operation;

an operation threshold for connecting the series connected power supply voltages V1 and V2 to allow device startup;

a power supply monitoring program operable to;

determine V1 and V2;

determine when both V1 and V2 exceed the operation threshold and responsively hold the main power switch in an ‘

ON’

state; and

determine when V1, V2 or both V1 and V2 fade below the cutoff threshold for disconnecting V1 and V2 to stop device operation and responsively hold the main power switch in an ‘

ON’

state until the function is complete.

11. The power supply monitoring and control system of claim 10, where the power supply monitoring program is further operable to:

determine when V1, V2 or both V1 and V2 fade below a fading threshold and responsively illuminate a warning indicator.

12. The power supply monitoring and control system of claim 10, where the cutoff threshold comprises a predetermined percentage of a nominal energy source voltage for disconnecting the voltages V1 and V2 from the device circuitry.

13. The power supply monitoring and control system of claim 10, where the operation threshold comprises a predetermined percentage of a nominal energy source voltage for allowing device startup.

14. The power supply monitoring and control system of claim 10, where the power supply monitoring program is further operable to:

determine when the function is complete;

illuminate a cutoff indicator; and

release the main power switch to an ‘

OFF’

state.

15. The power supply monitoring and control system of claim 14, where the power supply monitoring program is further operable to:

prevent reconnection of V1 and V2 to the device circuitry until V1 and V2 exceed the operation threshold.

16. The power supply monitoring and control system of claim 14, where the main power switch comprises a dropout switch.

17. The power supply monitoring and control system of claim 16, further comprising a switch state control input coupled between the dropout switch and the controller.

18. The power supply monitoring and control system of claim 16, where the function switch comprises a portable music player function switch.

19. The power supply monitoring and control system of claim 16, where the function switch comprises a cellular phone function switch.

20. A product comprising:

a machine readable medium; and

instructions encoded on the medium for execution by a controller in a power supply operated device, which will cause the controller to;

determine series connected power supply voltages V1 and V2;

initially hold a main power switch in an ‘

ON’

state;

determine when both V1 and V2 exceed an operation threshold and responsively hold the main power switch in the ‘

ON’

state;

determine when a device function is proceeding; and

determine when V1, V2 or both V1 and V2 fade below a cutoff threshold for disconnecting V1 and V2 to stop device operation, but responsively hold the main power switch in the ‘

ON’

state until the device function is no longer proceeding.

21. The product of claim 20, where the instructions stored on the medium will also cause the controller to:

determine when V1, V2 or both V1 and V2 fade below a fading threshold and responsively illuminate a warning indicator.

22. The product of claim 20, where the instructions stored on the medium will also cause the controller to:

determine when the device function is complete;

illuminate a cutoff indicator; and

release the main power switch to an ‘

OFF’

state.

23. The product of claim 22, where the instructions stored on the medium will also cause the controller to:

prevent reconnection of V1 and V2 to the device circuitry until V1 and V2 exceed the operation threshold.

24. The product of claim 22, where the instructions stored on the medium will also cause the controller to:

delay for a predetermined time after illuminating the cutoff indicator and releasing the main power switch.

25. The product of claim 22, where the instructions stored on the medium will cause the controller to determine the series connected power supply voltages V1 and V2 by:

determining a sum of V1 and V2 at a first measurement point;

determining V2 at a second measurement point; and

determining V1 from V2 and the sum of V1 and V2.