Selector circuit for power management in multiple battery systems

• US 6,977,482 B2
• Filed: 02/11/2003
• Issued: 12/20/2005
• Est. Priority Date: 02/11/2003
• Status: Expired due to Term

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Bucur, Constantin, Niculae, Marian, Popescu-Stanesti, Vlad
• Primary Examiner(s): Sparks, Donald
• Assistant Examiner(s): LUK, LAWRENCE W
• Application Number:
  US10/364,228
• Publication Number:
  US 20040160213A1
• Time in Patent Office: 1,043 Days
• Field of Search: 320/117, 320/116, 320/124, 320/126, 320/127, 320/128, 320/134, 320/136, 320/140, 320/125, 324/427, 324/142, 324/103, 713/300, 713/310, 713/320, 713/323, 713/324, 710/260, 710/261
• US Class Current: 320/116
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A selector circuit configured to select among a DC power source and a plurality of batteries for an electronic device. The selector circuit is responsive to an output signal from an associated power management unit. The selector circuit is further configured to permit parallel operation of two or more of the batteries. The selector circuit may further act to independently verify power conditions and override any instructions from the PMU in certain instances to enhance power supply safety and battery life. A power supply block including the selector circuit and an electronic device including the power supply block is also provided. The selector circuit may be integrated with a charging circuit on one integrated circuit.

Claims

1. A controller for a selector circuit configured to select among a DC power source and a plurality of batteries for an electronic device, said controller comprising:

a selector output circuit configured to provide selector output signals that control selection among said DC power source and said plurality of batteries, said selector output circuit providing said selector output signals in response to a power management unit (PMU) output signal from a PMU configured to run a power management routine; and

a first comparator, said first comparator configured to compare a first signal representative of a voltage level of said DC power source with a first threshold level and provide a DC source enable signal representative of a difference between said first signal and said first threshold level, said selector output circuit providing selector output signals to select said DC source and deselect said plurality of batteries if said DC source enable signal indicates said voltage level of said DC source is greater than said first threshold level.

2. The controller of claim 1, wherein said PMU output signal represents a desired selection of at least one of said plurality of batteries, and said selector output circuit provides selector output signals to select said DC source and deselect said plurality of batteries if said DC source enable signal indicates said voltage level of said DC source is greater than said first threshold level, thereby overriding said PMU output signal.

3. The controller of claim 1, further comprising a second comparator configured to compare said first signal representative of said voltage level of said DC power source with a second threshold level and provide a second output signal, said second threshold level greater than said first threshold level, said controller further configured to also enable charging of at least one of said plurality of batteries if said PMU output signal is representative of a use of at least one of said plurality of batteries and said second output signal is representative of said voltage level of said DC power source being greater than said second threshold level.

4. A controller for a selector circuit configured to select among a DC power source and a plurality of batteries for an electronic device, said controller comprising:

a selector output circuit configured to provide selector output signals that control selection among said DC power source and said plurality of batteries, said selector output circuit providing said selector output signals in response to a power management unit (PMU) output signal from a PMU configured to run a power management routine; and

a power crisis circuit, said power crises circuit configured to accept an input signal based on said PMU output signal and provide a diode mode signal upon detection of a power crises condition, said selector output circuit responsive to said diode mode signal to select each of said DC power source and said plurality of batteries such that said DC power source and each of said plurality of batteries is coupled in series to an associated diode thereby permitting only one of said DC power source or said plurality of batteries with a voltage level higher than a remainder of said power sources to supply said electronic device.

5. The controller of claim 4, wherein a system check signal representative of a voltage level of said electronic device less than a minimum voltage threshold level represents one said power crisis condition.

6. The controller of claim 4, wherein said selector output circuit provides an alert signal upon detection of said power crisis condition.

7. The controller of claim 4, wherein said controller deactivates said diode mode signal upon detection of said power crises condition being remedied.

8. The controller of claim 7, wherein a system check signal representative of a voltage level of said electronic device less than a minimum voltage threshold level represents one said power crisis condition, and wherein said system check signal representative of said voltage level of said electronic device greater than said minimum voltage threshold level represents said one power crises condition being remedied.

9. The controller of claim 8, wherein said controller comprises a third comparator configured to compare a third signal representative of a voltage level of said electronic device with a third signal representative of said minimum voltage threshold level and provide said system check signal representative of a difference between said voltage level of said electronic device and said minimum voltage threshold level.

10. An electronic device that may be powered by one or more of a plurality of rechargeable batteries or a DC power source, said electronic device comprising:

a power management unit configured to run a power management routine;

a charging circuit configured to control charging of said plurality of rechargeable batteries; and

a selector circuit configured to select at least one of said DC source and said plurality of batteries in response to a power management unit (PMU) output signal from said PMU, said selector circuit further comprising a first comparator, said first comparator configured to compare a first signal representative of a voltage level of said DC power source with a first threshold level and provide a DC source enable signal representative of a difference between said first signal and said first threshold level, said selector circuit providing selector output signals to select said DC source and deselect said plurality of batteries if said DC source enable signal indicates said voltage level of said DC source is greater than said first threshold level.

11. The electronic device of claim 10, wherein said PMU output signal represents a desired selection of at least one of said plurality of batteries, and said selector circuit provides selector output signals to select said DC source and deselect said plurality of batteries if said DC source enable signal indicates said voltage level of said DC source is greater than said first threshold level, thereby overriding said PMU output signal.

12. The electronic device of claim 10, wherein said selector circuit further comprising a second comparator configured to compare said first signal representative of said voltage level of said DC power source with a second threshold level and provide a second output signal, said second threshold level greater than said first threshold level, said selector circuit further configured to also enable charging of at least one of said plurality of batteries if said PMU output signal is representative of a use of at least one of said plurality of batteries and said second output signal is representative of said voltage level of said DC power source being greater than said second threshold level.

13. An electronic device that may be powered by one or more of a plurality of rechargeable batteries or a DC power source, said electronic device comprising:

a power management unit configured to run a power management routine;

a charging circuit configured to control charging of said plurality of rechargeable batteries; and

a selector circuit configured to select at least one of said DC source and said plurality of batteries in response to a power management unit (PMU) output signal from said PMU, wherein said selector circuit comprises a power crisis circuit and a selector output circuit, said power crises circuit configured to accept an input signal based on said PMU output signal and provide a diode mode signal upon detection of a power crises condition, said selector output circuit responsive to said diode mode signal to select each of said DC power source and said plurality of batteries such that said DC power source and each of said plurality of batteries is coupled in series to an associated diode thereby permitting only one of said DC power source or said plurality of batteries with a voltage level higher than a remainder of said power sources to supply said electronic device.

14. The electronic device of claim 13, wherein a system check signal representative of a voltage level of said electronic device less than a minimum voltage threshold level represents one said power crisis condition.

15. The electronic device of claim 13, wherein said selector output circuit provides an alert signal upon detection of said power crisis condition.

16. The electronic device of claim 13, wherein said selector output circuit deactivates said diode mode signal upon detection of said power crises condition being remedied.

17. The electronic device of claim 16, wherein a system check signal representative of a voltage level of said electronic device less than a minimum voltage threshold level represents one said power crisis condition, and wherein said system check signal representative of said voltage level of said electronic device greater than said minimum voltage threshold levels represents said one power crises condition being remedied.

18. The electronic device of claim 17, wherein said selector circuit comprises a third comparator configured to compare a third signal representative of a voltage level of said electronic device with a third signal representative of said minimum voltage threshold level and provide said system check signal representative of a difference between said voltage level of said electronic device and said minimum voltage threshold level.