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Patent US3889171A successfully refreshed from Google Patents.
US3889171A
Expired / Lapsed
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Battery Charger
Assignee: STANDBY SYSTEMS Inc
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Filing: 1973-10-12
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Granted: 1975-06-10
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Expires: 1993-10-12
Abstract
Abstract A battery charging circuit with a series current-limiting transistor varying in conductivity as a continuous function of the charging current and the terminal voltage of the battery. The conductivity of the transistor is controlled by a circuit including a thermistor, and is varied as a function of the difference between a reference potential and a variable potential, the latter being a function of plural conditions including the battery terminal voltage and the magnitude and duration of the charging current. The difference potential is measured across a bridge circuit that can be compensated for ambient temperature.
Inventors
- 👤 Jr Thomas C Hunter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:24
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/90; H02J7/971; H02J7/975; Y; Y10; Y10S; Y10S320/00; Y10S320/32
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
148 words
A battery charging circuit having, in combination, a direct current source, terminals for a battery having a predetermined float potential to be charged, a circuit connecting said source and terminals including a first variable impedance connected in series therewith, and control means including a thermally variable impedance varying as a continuous function of temperature and heat retaining and conducting means in position to transfer heat produced by current flowing in said first variable impedance to said thermally variable impedance, said control means being continuously responsive to increases in the temperature of said thermally variable impedance to produce corresponding decreases in the magnitude of said first variable impedance, said control means being continuously responsive to decreases in said current resulting from the charged state of the battery to produce corresponding increases in the magnitude of said first variable impedance continuously until said float potential is reached at said terminals.
Claim 2
Dependent Claim
148 words
A battery charging circuit having, in combination, a direct current source, terminals for a battery having a predetermined float potential to be charged, a circuit connecting said source and terminals including a first variable impedance connected in series therewith, and control means including a thermally variable impedance varying as a continuous function of temperature and heat retaining and conducting means in position to transfer heat produced by current flowing in said first variable impedance to said thermally variable impedance, said control means being continuously responsive to increases in the temperature of said thermally variable impedance to produce corresponding decreases in the magnitude of said first variable impedance, said control means being continuously responsive to decreases in said current resulting from the charged state of the battery to produce corresponding increases in the magnitude of said first variable impedance continuously until said float potential is reached at said terminals.
Claim 3
Dependent Claim
15 words
A circuit according to claim 1, in which the first variable impedance is a transistor.
Claim 4
Dependent Claim
15 words
A circuit according to claim 2, in which the thermally variable impedance is a thermistor.
Claim 5
Dependent Claim
44 words
A circuit according to claim 1, with a second thermally variable impedance included in said control means and in heat exchange relation with the ambient temperature and adapted to compensate for the effects of changes in ambient temperature on said first-mentioned thermally variable impedance.
Claim 6
Dependent Claim
65 words
A circuit according to claim 1, in which the control means include a bridge circuit having a first branch adapted to produce a substantially constant reference potential, a second branch including said thermally variable impedance and adapted to produce a control potential varying therewith, and means responsive to the difference between said reference and control potentials to vary the magnitude of said first variable impedance.
Claim 7
Dependent Claim
16 words
A circuit according to claim 5, in which said second branch is connected between said terminals.
Claim 8
Dependent Claim
18 words
A circuit according to claim 5, in which said first and second branches are connected between said terminals.
Claim 9
Dependent Claim
43 words
A ciicuit according to claim 5, in which said second branch includes a second thermally variable impedance in heat exchange relation with the ambient temperature and adapted to compensate for the effects of changes in ambient temperature on said first-mentioned thermally variable impedance.
Claim 10
Dependent Claim
18 words
A circuit according to claim 8, in which said first and second branches are connected between said terminals.
Claim 11
Dependent Claim
33 words
A circuit according to claim 9, in which the first variable impedance is a transistor having its base-emitter circuit controlled by said means responsive to the difference between said reference and control potentials.
Claim 12
Dependent Claim
176 words
A battery charging circuit having, in combination, a direct current source, terminals for a battery having a predetermined float potential to be charged, and a first circuit connecting said source and terminals including in series therewith a first variable impedance having a control circuit for continuous variation of the magnitude of said impedance, said control circuit being connected between said terminals and including first means responsive to a decrease in the voltage therebetween to decrease said first variable impedance and second means including a thermally variable impedance varying as a continuous function of temperature and heat retaining and conducting means in position to transfer heat produced by current flowing in said first variable impedance to said thermally variable impedance, said second means being responsive to an increase in the temperature of said thermally variable impedance to decreAse said first variable impedance, said second means being responsive to a decrease in said current resulting from the charged state of the battery to increase said first variable impedance continuously until said float potential is reached at said terminals.
Claim 13
Dependent Claim
176 words
A battery charging circuit having, in combination, a direct current source, terminals for a battery having a predetermined float potential to be charged, and a first circuit connecting said source and terminals including in series therewith a first variable impedance having a control circuit for continuous variation of the magnitude of said impedance, said control circuit being connected between said terminals and including first means responsive to a decrease in the voltage therebetween to decrease said first variable impedance and second means including a thermally variable impedance varying as a continuous function of temperature and heat retaining and conducting means in position to transfer heat produced by current flowing in said first variable impedance to said thermally variable impedance, said second means being responsive to an increase in the temperature of said thermally variable impedance to decreAse said first variable impedance, said second means being responsive to a decrease in said current resulting from the charged state of the battery to increase said first variable impedance continuously until said float potential is reached at said terminals.
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) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |