US5268845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for detecting low battery state without precise calibration
Assignee: Dell USA LP
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Filing: 1991-02-14
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Granted: 1993-12-07
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Expires: 2011-02-14
Abstract
Abstract A portable electronic system, which can accurately predict impending battery failure, without using expensive comparators, by using voltage and current measurements to determine the source impedance of a battery. Preferably two banks of batteries are used, with a load-switching relay; the voltage and current of both banks is monitored, so that voltage drop under load can be monitored. Alternatively, the voltage variation of a single battery bank can simply be correlated to the current drawn by a changing load.
Inventors
- 👤 Warren W. Startup
- 👤 Gregory N. Stewart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:57
CPC Classifications
G; G06; G06F; G06F1/00; G06F1/16; G06F1/1613; G06F1/1615; G06F1/1616; G01; G01R; G01R31/00; G01R31/36; G01R31/3644; G01R31/3648; G01R31/389; G06F1/1633; G06F1/1635; G06F1/1675; G06F1/1677; G06F1/26; G06F1/28; H; H02; H02J; H02J9/00; H02J9/04; H02J9/06; H02J9/061; G01R31/382; G01R31/3842
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
138 words
A portable electronic system, comprising: at least one microprocessor; at least one battery power connection, and a ground terminal; a voltage-sensing interface, connected so that said microprocessor can detect the voltage drop across said battery connection; and a current-sensing interface, connected so that said microprocessor can detect the current flow through said battery connection; said microprocessor being configured to repeatedly compare the voltage and current at said battery connection, at an instant when the current through said connection is small, with the voltage and current at said battery connection at another substantially contemporaneous instant when the current through said connection is larger; and to indicate imminent battery failure when the source impedance seen at said battery connection is accordingly detected to have risen in a pattern corresponding to the internal impedance of a battery which is imminently failing.
Claim 2
Dependent Claim
138 words
A portable electronic system, comprising: at least one microprocessor; at least one battery power connection, and a ground terminal; a voltage-sensing interface, connected so that said microprocessor can detect the voltage drop across said battery connection; and a current-sensing interface, connected so that said microprocessor can detect the current flow through said battery connection; said microprocessor being configured to repeatedly compare the voltage and current at said battery connection, at an instant when the current through said connection is small, with the voltage and current at said battery connection at another substantially contemporaneous instant when the current through said connection is larger; and to indicate imminent battery failure when the source impedance seen at said battery connection is accordingly detected to have risen in a pattern corresponding to the internal impedance of a battery which is imminently failing.
Claim 3
Dependent Claim
11 words
The system of claim 1, wherein said microprocessor is a microcontroller.
Claim 4
Dependent Claim
17 words
The system of claim 1, wherein said microprocessor is a microcontroller, and includes on-chip analog interface circuits.
Claim 5
Dependent Claim
12 words
The system of claim 1, wherein said system is a portable computer.
Claim 6
Dependent Claim
21 words
The system of claim 1, wherein said system is a portable computer, and said microprocessor is separate from the CPU thereof.
Claim 7
Dependent Claim
221 words
A portable electronic system, comprising: at least one microprocessor; first and second battery power connections; a voltage-sensing interface, connected so that said microprocessor can detect the voltage drop across said first battery connection, and also, independently thereof, can detect the voltage drop across said second battery connection; and a current-sensing interface, connected so that said microprocessor can detect the current flow through said first battery connection, and also, independently thereof, can detect the current flow through said second battery connection; said microprocessor being configured to repeatedly compare the voltage and current at said first battery connection, at an instant when the current through said first battery connection is small, with the voltage and current at said first battery connection at another substantially contemporaneous instant when the current through said first battery connection is larger, and to repeatedly compare the voltage and current at said second battery connection, at an instant when the current through said second battery connection is small, with the voltage and current at said second battery connection at another substantially contemporaneous instant when the current through said second battery connection is larger; and to indicate imminent battery failure when the source impedance seen at said battery connection is accordingly detected to have risen in a pattern corresponding to the internal impedance of a battery which is imminently failing.
Claim 8
Dependent Claim
221 words
A portable electronic system, comprising: at least one microprocessor; first and second battery power connections; a voltage-sensing interface, connected so that said microprocessor can detect the voltage drop across said first battery connection, and also, independently thereof, can detect the voltage drop across said second battery connection; and a current-sensing interface, connected so that said microprocessor can detect the current flow through said first battery connection, and also, independently thereof, can detect the current flow through said second battery connection; said microprocessor being configured to repeatedly compare the voltage and current at said first battery connection, at an instant when the current through said first battery connection is small, with the voltage and current at said first battery connection at another substantially contemporaneous instant when the current through said first battery connection is larger, and to repeatedly compare the voltage and current at said second battery connection, at an instant when the current through said second battery connection is small, with the voltage and current at said second battery connection at another substantially contemporaneous instant when the current through said second battery connection is larger; and to indicate imminent battery failure when the source impedance seen at said battery connection is accordingly detected to have risen in a pattern corresponding to the internal impedance of a battery which is imminently failing.
Claim 9
Dependent Claim
17 words
The system of claim 6, wherein said microprocessor is a microcontroller, and includes on-chip analog interface circuits.
Claim 10
Dependent Claim
12 words
The system of claim 6, wherein said system is a portable computer.
Claim 11
Dependent Claim
35 words
The system of claim 6, wherein first battery connection includes a ground terminal, and said second battery connection also includes a ground terminal which is common with the ground terminal of said first battery connection.
Claim 12
Dependent Claim
21 words
The system of claim 6, wherein said system is a portable computer, and said microprocessor is separate from the CPU thereof.
Claim 13
Independent Claim
78 words
A method for automatic battery management, in a portable electronic system, comprising the operations of: repeatedly measuring the voltage and current of a battery bank, under changing load conditions; making a calculation, in a microprocessor, which is substantially equivalent to estimating the internal impedance of the battery bank; and indicating imminent battery failure when the internal impedance of the battery bank is accordingly estimated to have risen in a pattern corresponding to a battery which is approaching failure.
Claim 14
Independent Claim
78 words
A method for automatic battery management, in a portable electronic system, comprising the operations of: repeatedly measuring the voltage and current of a battery bank, under changing load conditions; making a calculation, in a microprocessor, which is substantially equivalent to estimating the internal impedance of the battery bank; and indicating imminent battery failure when the internal impedance of the battery bank is accordingly estimated to have risen in a pattern corresponding to a battery which is approaching failure.
Claim 15
Dependent Claim
11 words
The method of claim 11, wherein said microprocessor is a microcontroller.
Claim 16
Dependent Claim
17 words
The method of claim 11, wherein said microprocessor is a microcontroller, and includes on-chip analog interface circuits.
Claim 17
Dependent Claim
21 words
The method of claim 11, wherein said system is a portable computer, and said microprocessor is separate from the CPU thereof.
Claim 18
Independent Claim
91 words
A method for automatic battery management, in a portable electronic system, comprising the operations of: repeatedly measuring the battery voltage and load current of a battery bank, under changing load conditions; making a calculation, in a microprocessor, of how the battery voltage responds when the load current changes; and indicating imminent battery failure when an observed change in load current causes a change in battery voltage which is sufficiently large, in relation to the observed change in load current, to approximate the voltage-change-to-current-change ratio of a battery which is approaching failure.
Claim 19
Independent Claim
91 words
A method for automatic battery management, in a portable electronic system, comprising the operations of: repeatedly measuring the battery voltage and load current of a battery bank, under changing load conditions; making a calculation, in a microprocessor, of how the battery voltage responds when the load current changes; and indicating imminent battery failure when an observed change in load current causes a change in battery voltage which is sufficiently large, in relation to the observed change in load current, to approximate the voltage-change-to-current-change ratio of a battery which is approaching failure.
Claim 20
Dependent Claim
17 words
The method of claim 15, wherein said microprocessor is a microcontroller, and includes on-chip analog interface circuits.
Claim 21
Dependent Claim
21 words
The method of claim 15, wherein said system is a portable computer, and said microprocessor is separate from the CPU thereof.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-12-06 | 1997-06-07 | 1997-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-12-06 | 2001-06-07 | 2001-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-12-06 | 2005-06-07 | 2005-12-07 | $7700.00 | Window Closed / Lapsed |