US5223748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Battery manager
Assignee: Maxim Integrated Products Inc
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Filing: 1990-12-11
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Granted: 1993-06-29
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Expires: 2010-12-11
Abstract
Abstract Battery monitor (100) with a transient pull down (172) for backup batteries which is active during power up and prevents the feedthrough charging of low or dead batteries causing a spurious power fail indication.
Inventors
- 👤 Eric W. Mumper
- 👤 Donald R. Dias
- 👤 Hal Kurkowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:59
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/165; G01R19/16533; G01R19/16538; G01R19/16542; H; H02; H02J; H02J9/00; H02J9/04; H02J9/06; H02J9/061; G01R31/00; G01R31/36; G01R31/3644; G01R31/3648
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
92 words
An integrated circuit, comprising: (a) an input power terminal; (b) a backup power terminal; (c) an output power terminal; (d) a first switch between said input power terminal and said output power terminal; (e) a second switch between said backup power terminal and said output power terminal; (f) pull down circuitry switchably connected to said backup power terminal; and (g) control circuitry transiently connecting said pull down circuitry to said backup power terminal when the potential of said input power terminal increases from a power fail level towards a power supply level.
Claim 2
Dependent Claim
92 words
An integrated circuit, comprising: (a) an input power terminal; (b) a backup power terminal; (c) an output power terminal; (d) a first switch between said input power terminal and said output power terminal; (e) a second switch between said backup power terminal and said output power terminal; (f) pull down circuitry switchably connected to said backup power terminal; and (g) control circuitry transiently connecting said pull down circuitry to said backup power terminal when the potential of said input power terminal increases from a power fail level towards a power supply level.
Claim 3
Dependent Claim
41 words
The circuit of claim 1, wherein: (a) said control circuitry connects said pull down circuitry for a first predetermined time period if the time constant of increase of said potential is at most as large as said first predetermined time period.
Claim 4
Dependent Claim
23 words
The circuit of claim 2, wherein: (a) said first predetermined time period is determined by charging a fixed capacitor through a fixed resistor.
Claim 5
Dependent Claim
40 words
The circuit of claim 2, wherein: (a) said control circuitry connects said pull down circuitry for a second time period dependent upon said time constant of increase if said time constant of increase is greater than said second time period.
Claim 6
Independent Claim
37 words
A method of managing a backup power supply, comprising the steps of: (a) sensing an increase in the potential of a primary power supply; and then (b) applying a transient pull down to a backup power supply.
Claim 7
Independent Claim
37 words
A method of managing a backup power supply, comprising the steps of: (a) sensing an increase in the potential of a primary power supply; and then (b) applying a transient pull down to a backup power supply.
Claim 8
Dependent Claim
27 words
The method of claim 5, wherein: (a) said transient pull down is for a fixed time period determined by charging a fixed capacitor through a fixed resistor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-28 | 1996-12-28 | 1997-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-28 | 2000-12-28 | 2001-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-28 | 2004-12-28 | 2005-06-29 | $7700.00 | Window Closed / Lapsed |