Patent US4862013A successfully refreshed from Google Patents.
US4862013A
Expired / Lapsed
US
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Constant current source and battery charger
Assignee: Zenith Electronics LLC
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Filing: 1988-11-16
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Granted: 1989-08-29
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Expires: 2008-11-16
Abstract
Abstract A constant current battery charger includes a bucking regulator comprising a power switch transistor, a diode, an inductor and a voltage sensitive switch with adjustable delay for controlling the power switch transistor. The hysteresis or delay is obtained with a Schmitt trigger and the effect is a stable pulse width modulator in which the duty cycle of the power switch transistor is varied. A temperature sensor adds resistance to change the sensitivity of the switch and reduce charging current when a predetermined battery temperature is reached. A speed up circuit consisting of a shorting transistor is connected across the base-emitter of the switch transistor.
Inventors
- 👤 John G. Konopka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:34
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/90; H02J7/971; H02J7/975; H02J7/977
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
112 words
A speed up circuit for a power transistor switch operated from a single-ended power supply comprising: a switch transistor coupled between said power supply and a load circuit; control means for controlling the conduction of said switch transistor in response to a control signal; said control means comprising a shorting transistor connected across the base-emitter junction of said switch transistor and trigger means, including a trigger transistor, for rapidly driving said shorting transistor into conduction in response to said control signal; and a diode coupled across the base-emitter circuit of said shorting transistor and a resistor and capacitor series circuit connected between said diode and the load circuit of said trigger transistor.
Claim 2
Dependent Claim
112 words
A speed up circuit for a power transistor switch operated from a single-ended power supply comprising: a switch transistor coupled between said power supply and a load circuit; control means for controlling the conduction of said switch transistor in response to a control signal; said control means comprising a shorting transistor connected across the base-emitter junction of said switch transistor and trigger means, including a trigger transistor, for rapidly driving said shorting transistor into conduction in response to said control signal; and a diode coupled across the base-emitter circuit of said shorting transistor and a resistor and capacitor series circuit connected between said diode and the load circuit of said trigger transistor.
Claim 3
Dependent Claim
25 words
The circuit of claim 1 wherein said resistor and capacitor and said diode are connected in parallel with the load circuit of said trigger transistor.
Claim 4
Dependent Claim
16 words
The circuit of claim 2 wherein said load circuit of said trigger transistor comprises a 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) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |