Patent US4555742A successfully refreshed from Google Patents.
US4555742A
Expired / Lapsed
US
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Short detection circuit and method for an electrical load
Assignee: Motorola Solutions Inc
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Filing: 1984-05-09
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Granted: 1985-11-26
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Expires: 2004-05-09
Abstract
Abstract A short detection circuit and method for operatively controlling current in an electrical load such as an alternator field coil includes a driving device such as a Darlington transistor for driving the electrical load. Detecting means selectively withhold and provide operating current to the driving means when a shorted and not shorted condition of the electrical load is respectively detected at the driven terminal of the driving device.
Inventors
- 👤 Randall C. Gray
- 👤 Robert B. Jarrett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:40
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/08; H03K17/082; H03K17/0826; H03K17/51; H03K17/56; H03K17/60; H03K17/615
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
149 words
A short detection circuit for operatively controlling current in an electrical load connected to a source voltage line comprising: means for driving an electrical load having first, second and third terminals thereof, said first terminal being connected to said electrical load and said second terminal being connected to a common voltage line; and means for detecting a short circuit current in said electrical load connected to said third terminal of said driving means, said means for detecting comprising a current source for providing an operating current to said driving means and an SCR for disabling said current source in response to a shorted condition of said electrical load, said detecting means selectively withholding and providing said operating current to said driving means when a shorted and not shorted condition of said electrical load to said source voltage line is respectively detected at said third terminal of said driving means.
Claim 2
Dependent Claim
149 words
A short detection circuit for operatively controlling current in an electrical load connected to a source voltage line comprising: means for driving an electrical load having first, second and third terminals thereof, said first terminal being connected to said electrical load and said second terminal being connected to a common voltage line; and means for detecting a short circuit current in said electrical load connected to said third terminal of said driving means, said means for detecting comprising a current source for providing an operating current to said driving means and an SCR for disabling said current source in response to a shorted condition of said electrical load, said detecting means selectively withholding and providing said operating current to said driving means when a shorted and not shorted condition of said electrical load to said source voltage line is respectively detected at said third terminal of said driving means.
Claim 3
Dependent Claim
19 words
The short detection circuit of claim 1 wherein said detecting means comprises a reset input for unlatching said SCR.
Claim 4
Dependent Claim
120 words
A short detection method for operatively controlling current in an electrical load connected to a source voltage line comprising the steps of: furnishing driving means coupling said electrical load to a common voltage line, said driving means having an input line thereto; providing operating current, by means of a current source, to said input line of said driving means when a not shorted condition of said electrical load to said source voltage line is detected at said input line; and withholding operating current to said input line of said driving means, by means of an SCR for disabling said current source, when a shorted condition of said electrical load to said source voltage line is detected at said input line.
Claim 5
Dependent Claim
120 words
A short detection method for operatively controlling current in an electrical load connected to a source voltage line comprising the steps of: furnishing driving means coupling said electrical load to a common voltage line, said driving means having an input line thereto; providing operating current, by means of a current source, to said input line of said driving means when a not shorted condition of said electrical load to said source voltage line is detected at said input line; and withholding operating current to said input line of said driving means, by means of an SCR for disabling said current source, when a shorted condition of said electrical load to said source voltage line is detected at said input line.
Claim 6
Dependent Claim
153 words
An alternator including a short detection circuit for operatively controlling current in a field coil thereof connected to a battery voltage line comprising: means for driving said field coil having first, second and third terminals thereof, said first terminal being connected to said field coil and said second terminal being connected to a ground voltage line; and means for detecting a short circuit current in said field coil connected to said third terminal of said driving means, said means for detecting comprising a current source for providing an operating current to said driving means and an SCR for disabling said current source in response to a shorted condition of said field coil, said detecting means selectively withholding and providing said operating current to said driving means when a shorted and not shorted condition of said field coil to said battery voltage line is respectively detected at said third terminal of said driving means.
Claim 7
Dependent Claim
153 words
An alternator including a short detection circuit for operatively controlling current in a field coil thereof connected to a battery voltage line comprising: means for driving said field coil having first, second and third terminals thereof, said first terminal being connected to said field coil and said second terminal being connected to a ground voltage line; and means for detecting a short circuit current in said field coil connected to said third terminal of said driving means, said means for detecting comprising a current source for providing an operating current to said driving means and an SCR for disabling said current source in response to a shorted condition of said field coil, said detecting means selectively withholding and providing said operating current to said driving means when a shorted and not shorted condition of said field coil to said battery voltage line is respectively detected at said third terminal of said driving means.
Claim 8
Dependent Claim
17 words
The alternator of claim 4 wherein said detecting means comprises a reset input for unlatching said SCR.
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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) | 1988-11-25 | 1989-05-27 | 1989-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-25 | 1993-05-27 | 1993-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-25 | 1997-05-27 | 1997-11-26 | $7700.00 | Window Closed / Lapsed |