AC adapter with automatically optimized output voltage and power

• US 5,847,543 A
• Filed: 06/30/1997
• Issued: 12/08/1998
• Est. Priority Date: 06/30/1997
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Carroll, Barry N.
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US08/885,021
• Time in Patent Office: 526 Days
• Field of Search: 320/106, 320/110, 320/116, 320/128, 320/137, 320/140, 320/125, 320/158, 320/163, 320/DIG. 10, 320/105, 320/114, 320/121, 320/148, 320/155
• US Class Current: 320/125
• CPC Class Codes: G06F 1/1632 External expansion units, e.g. docking stations
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• 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: Y02E 60/10 Energy storage using batteries

Abstract

A portable docking and precharging station with an AC adapter with automatically optimized output voltage and power. An IIC communications link between the computer and AC adapter carries signals which adjust the AC adapter'"'"'s voltage and power settings, depending on the charge state of the battery and whether the computer is on or off. If the computer is on, full output power is provided from the AC adapter. If the computer is off, the output power from the AC adapter is reduced so that the current cannot exceed the battery manufacturer'"'"'s recommended charging rates. Preferably the regulated output voltage and the current limit are both changed when the change between modes occurs.

Claims

1. A method for powering a portable electronic appliance and/or recharging a rechargeable battery, comprising the steps of:

(a.) if the appliance is drawing power;

performing conversion of AC power to provide a DC power supply output at a first voltage level and at a first maximum power level; and

(b.) if the appliance is not drawing power and if the battery is being recharged, performing conversion of AC power to provide said DC power supply output at a second voltage level which is different from said first voltage level and a second maximum power level which is different from said first maximum power level.

2. The method according to claim 1, wherein said portable appliance is a computer.

3. The method according to claim 1, wherein said portable appliance is a computer, and said step of performing conversion is performed by a docking station which mates with said computer.

4. The method according to claim 1, wherein said step of performing conversion is performed within said appliance.

5. The method according to claim 1, wherein said circuit for converting power comprises a digital potentiometer that communicates with a microcontroller.

6. The method according to claim 1, wherein said first maximum power level is higher than said second maximum power level, and said first voltage level is lower than said second voltage level.

7. The method according to claim 1, wherein said first power level is 50 W and said first voltage level is 14.1 VDC.

8. The method according to claim 1, wherein said second power level is 40 W and said second voltage level is 18.85 VDC.

9. A method for powering a portable computer docking station which can receive and provide power to both a portable computer and a rechargeable battery, comprising the steps of:

(a.) if the computer is docked and actively operating, performing conversion of AC power to provide a first DC output voltage level which is shared by both the computer and the battery, at a first maximum power level; and

(b.) if the battery is being recharged and the computer is not actively operating, performing conversion of AC power to provide a second DC output voltage level which is different from said first DC output voltage level, at a second maximum power level which is different from said first maximum power level.

10. The method according to claim 9, wherein said portable computer docking station comprises a microcontroller which communicates with a digital potentiometer.

11. The method according to claim 9, wherein said first maximum power level is 50 W and said first DC output voltage level is 14.1 VDC.

12. The method according to claim 9, wherein said second maximum power level is 40 W and said second DC output voltage level is 18.85 VDC.

13. The method according to claim 9, wherein said first DC output voltage level is fed back to a circuitry on a primary side of an isolation transformer.

14. The method according to claim 9, wherein said first DC output voltage is coupled to a sensing circuit which generates an error signal.

15. The method according to claim 9, wherein said second DC output voltage is coupled to a digital potentiometer;

said digital potentiometer operatively connected to a microcontroller for bi-directional communication of a digital representation of said second DC output voltage.

16. A portable computer docking subsystem, comprising:

a power supply comprising

an AC power conversion circuit that in a first mode provides a first DC output voltage level and a first maximum power level; and

in a second mode provides a second DC output voltage and a second maximum power level which is different from said first power level; and

a plurality of slots comprising connections to said power supply for receiving power.

17. The subsystem according to claim 16, wherein said AC power conversion circuit comprises a feedback loop from a secondary side of an isolation transformer to a primary side of said isolation transformer.

18. The subsystem according to claim 16, wherein said AC power conversion circuit comprises a digital potentiometer which communicates with a microcontroller.

19. The subsystem according to claim 16, wherein said first DC output voltage is coupled to a sensing circuit which generates an error signal.

20. The subsystem according to claim 16, wherein said first maximum power level is 50 W and said first DC output voltage level is 14.1 VDC.

21. The subsystem according to claim 16, wherein said second maximum power level is 40 W and said second DC output voltage level is 18.85 VDC.

22. A portable computer system, comprising:

a computer, comprising memory and a programmable processor, integrated in a common portable chassis;

at least one rechargeable battery attachable to said chassis, and electrically connected to power said processor under at least some circumstances; and

a power conversion circuit, connectable to an AC power outlet, for providing one or more power supply outputs to said processor and said battery,

at a first voltage level and a first maximum power level, if the computer is drawing power,

and at a second voltage level which is different from said first voltage level and a second maximum power level which is different from said first maximum power level, if the appliance is not drawing power and if the battery is being recharged.

23. The system according to claim 22, wherein said power conversion circuit comprises a microcontroller operatively connected to control a digital potentiometer.

24. The system according to claim 22, wherein said power conversion circuit comprises an isolation transformer that is switchable on a primary side.

25. The system according to claim 22, wherein said power conversion circuit comprises a current sensing circuit operatively connected to a digital potentiometer.

26. The system according to claim 22, wherein said power conversion circuit comprises a feedback loop from a secondary side of an isolation transformer to a primary side of said isolation transformer.

27. The system according to claim 22, wherein said first power level is 50 W and said first voltage level is 14.1 VDC.

28. The system according to claim 22, wherein said second power level is 40 W and said second voltage level is 18.85 VDC.

29. A portable computer system, comprising:

a computer, comprising memory and a programmable processor, integrated in a common portable chassis;

at least one rechargeable battery attachable to said chassis, and electrically connected to power said processor under at least some circumstances; and

power conversion means, connectable to an AC power outlet, for providing one or more power supply outputs to said processor and said battery,

at a first voltage level and a first maximum power level, if the computer is drawing power,

and at a second voltage level which is different from said first voltage level and a second maximum power level which is different from said first maximum power level, if the appliance is not drawing power and if the battery is being recharged.

30. The system according to claim 29, wherein said means for converting power comprises a microcontroller which communicates with a digital potentiometer.

31. The system according to claim 29, wherein said means for converting power comprises an isolation transformer that is switchable on a primary side.

32. The system according to claim 29, wherein said means for converting power comprises a current sensing circuit operatively connected to a digital potentiometer.

33. The system according to claim 29, wherein said means for converting power comprises a feedback loop from a secondary side of an isolation transformer to a primary side of said isolation transformer.

34. The system according to claim 29, wherein said first power level is 50 W and said first voltage level is 14.1 VDC.

35. The system according to claim 29, wherein said second power level is 40 W and said second voltage level is 18.85 VDC.