US5196784A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Isolated current monitoring circuit for measuring direct and high duty factor currents
Assignee: Raytheon Co
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Filing: 1991-03-18
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Granted: 1993-03-23
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Expires: 2011-03-18
Abstract
Abstract A method and circuit for measuring direct and high duty factor current in a conductor (1) with minimal interference with the operation of a monitored circuit. Current flow in the conductor is magnetically sensed with a transformer T1 having a primary winding connected electrically in series with the conductor (1). The transformer T1 is driven into saturation during a first time interval and brought out of saturation during a second time interval. After the transformer T1 is brought out of saturation, an output signal is provided which is proportional to the flow of current in the conductor (1).
Inventors
- 👤 Earl M. Estes, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:38
CPC Classifications
G; G01; G01R; G01R15/00; G01R15/14; G01R15/18; G01R15/183
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
312 words
An isolated current monitoring circuit for measuring direct and high duty factor current in a conductor comprising: A. transformer means for magnetically sensing current flow in said conductor, said transformer means including a transformer having a primary winding connected electrically in series with said conductor and a secondary winding; B. means for driving said transformer into saturation during a first time interval including: a. an operational amplifier with an inverting input connected to the first end of said secondary winding of said transformer, a noninverting input connected to means for providing a reference potential and an output terminal connected via a first resistor to the first end of the secondary winding of said transformer; and b. means connected to said inverting input of said operational amplifier for providing a saturation control signal; C. means for bringing said transformer out of saturation and operation said transformer as a current transformer during a second time interval, comprising: c. said noninverting input connected to means for providing a reference potential and an output terminal of said operational amplifier connected via a first resistor to the first terminal of the secondary winding of said transformer; and d. a second resistor connected to said inverting input of said operational amplifier at one end and the first end of said secondary winding of said transformer at a second end thereof; D. said means for providing a reference potential comprises: e. a third resistor connected to said noninverting input of said operational amplifier at one end and a potential well at a second end thereof; and f. a fourth resistor connected to said inverting input of said operational amplifier at one end and a source of potential at a second end thereof; and E. means for providing an output signal, after the initiation of the second time interval, which is proportional to the flow of current in said conductor.
Claim 2
Dependent Claim
312 words
An isolated current monitoring circuit for measuring direct and high duty factor current in a conductor comprising: A. transformer means for magnetically sensing current flow in said conductor, said transformer means including a transformer having a primary winding connected electrically in series with said conductor and a secondary winding; B. means for driving said transformer into saturation during a first time interval including: a. an operational amplifier with an inverting input connected to the first end of said secondary winding of said transformer, a noninverting input connected to means for providing a reference potential and an output terminal connected via a first resistor to the first end of the secondary winding of said transformer; and b. means connected to said inverting input of said operational amplifier for providing a saturation control signal; C. means for bringing said transformer out of saturation and operation said transformer as a current transformer during a second time interval, comprising: c. said noninverting input connected to means for providing a reference potential and an output terminal of said operational amplifier connected via a first resistor to the first terminal of the secondary winding of said transformer; and d. a second resistor connected to said inverting input of said operational amplifier at one end and the first end of said secondary winding of said transformer at a second end thereof; D. said means for providing a reference potential comprises: e. a third resistor connected to said noninverting input of said operational amplifier at one end and a potential well at a second end thereof; and f. a fourth resistor connected to said inverting input of said operational amplifier at one end and a source of potential at a second end thereof; and E. means for providing an output signal, after the initiation of the second time interval, which is proportional to the flow of current in said conductor.
Claim 3
Dependent Claim
49 words
The invention of claim 1 wherein said means for bringing said transformer out of saturation during a second time interval further includes a diode having a cathode terminal connected to the first end of said secondary winding of said transformer and an anode terminal connected to said potential well.
Claim 4
Dependent Claim
20 words
The invention of claim 2 wherein said diode is connected between said second ends of said second and third resistors.
Claim 5
Dependent Claim
19 words
The invention of claim 3 wherein said second end of said secondary winding is connected to said potential well.
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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) | 1996-03-22 | 1996-09-21 | 1997-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-03-22 | 2000-09-21 | 2001-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-03-22 | 2004-09-21 | 2005-03-23 | $7700.00 | Window Closed / Lapsed |