Patent US5883793A successfully refreshed from Google Patents.
US5883793A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Clamp circuit for a power converter and method of operation thereof
Assignee: Nokia of America Corp
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Filing: 1998-04-30
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Granted: 1999-03-16
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Expires: 2018-04-30
Abstract
Abstract For use with a power converter having first and second power switches coupled between a converter input and a primary winding of a transformer to impress an input voltage across the primary winding, a voltage clamp circuit for, and method of, resetting the transformer and a power converter employing the clamp circuit or the method. In one embodiment, the clamp circuit includes: (1) first and second reset windings coupled between the first and second power switches, (2) first and second energy storage devices coupled between the primary winding and the first and second reset windings, respectively, and (3) first and second switching circuits, coupled to the first reset winding and the second reset winding, respectively, that provide an electrical path from the primary winding to the converter input through the first and second reset windings, respectively, when the first and second power switches are not conducting.
Inventors
- 👤 Richard W. Farrington
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:58
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33569
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
123 words
For use with a power converter having first and second power switches coupled between a converter input and a primary winding of a transformer to impress an input voltage across said primary winding, a voltage clamp circuit for resetting said transformer, comprising: first and second reset windings coupled between said first and second power switches; first and second energy storage devices coupled between said primary winding and said first and second reset windings, respectively; and first and second switching circuits, coupled to said first reset winding and said second reset winding, respectively, that provide an electrical path from said primary winding to said converter input through said first and second reset windings, respectively, when said first and second power switches are not conducting.
Claim 2
Dependent Claim
123 words
For use with a power converter having first and second power switches coupled between a converter input and a primary winding of a transformer to impress an input voltage across said primary winding, a voltage clamp circuit for resetting said transformer, comprising: first and second reset windings coupled between said first and second power switches; first and second energy storage devices coupled between said primary winding and said first and second reset windings, respectively; and first and second switching circuits, coupled to said first reset winding and said second reset winding, respectively, that provide an electrical path from said primary winding to said converter input through said first and second reset windings, respectively, when said first and second power switches are not conducting.
Claim 3
Dependent Claim
17 words
The clamp circuit as recited in claim 1 wherein said first and second storage devices are capacitors.
Claim 4
Dependent Claim
22 words
The clamp circuit as recited in claim 1 wherein said first and second switching circuits each comprise series-coupled first and second diodes.
Claim 5
Dependent Claim
44 words
The clamp circuit as recited in claim 1 wherein said first and second switching circuits each comprise a diode coupled between said first energy storage device and said first reset winding and between said second energy storage device and said second reset winding, respectively.
Claim 6
Dependent Claim
20 words
The clamp circuit as recited in claim 1 wherein said first and second reset windings have identical numbers of turns.
Claim 7
Dependent Claim
25 words
The clamp circuit as recited in claim 1 wherein a maximum duty cycle of said first and second power switches is less than about 0.67.
Claim 8
Dependent Claim
19 words
The clamp circuit as recited in claim 1 wherein said first and second storage devices are of equivalent capacity.
Claim 9
Dependent Claim
92 words
For use with a power converter having first and second power switches coupled between a converter input and a primary winding of a transformer to impress an input voltage across said primary winding, a method of resetting said transformer, comprising the steps of: energizing first and second energy storage devices coupled to said primary winding; and transferring electrical power from said first and second storage devices to first and second reset windings of said transformer via first and second switching circuits, respectively, when said first and second power switches are not conducting.
Claim 10
Dependent Claim
92 words
For use with a power converter having first and second power switches coupled between a converter input and a primary winding of a transformer to impress an input voltage across said primary winding, a method of resetting said transformer, comprising the steps of: energizing first and second energy storage devices coupled to said primary winding; and transferring electrical power from said first and second storage devices to first and second reset windings of said transformer via first and second switching circuits, respectively, when said first and second power switches are not conducting.
Claim 11
Dependent Claim
16 words
The method as recited in claim 8 wherein said first and second storage devices are capacitors.
Claim 12
Dependent Claim
21 words
The method as recited in claim 8 wherein said first and second switching circuits each comprise series-coupled first and second diodes.
Claim 13
Dependent Claim
43 words
The method as recited in claim 8 wherein said first and second switching circuits each comprise a diode coupled between said first energy storage device and said first reset winding and between said second energy storage device and said second reset winding, respectively.
Claim 14
Dependent Claim
19 words
The method as recited in claim 8 wherein said first and second reset windings have identical numbers of turns.
Claim 15
Dependent Claim
24 words
The method as recited in claim 8 wherein a maximum duty cycle of said first and second power switches is less than about 0.67.
Claim 16
Dependent Claim
18 words
The method as recited in claim 8 wherein said first and second storage devices are of equivalent capacity.
Claim 17
Dependent Claim
125 words
A power converter, comprising: a transformer having a primary winding and a secondary winding; first and second power switches coupled between a converter input and said primary winding to impress an input voltage thereacross; and a voltage clamp circuit for resetting said transformer, including: first and second reset windings coupled between said first and second power switches, first and second energy storage devices coupled between said primary winding and said first and second reset windings, respectively, and first and second switching circuits, coupled to said first reset winding and said second reset winding, respectively, that provide an electrical path from said primary winding to said converter input through said first and second reset windings, respectively, when said first and second power switches are not conducting.
Claim 18
Dependent Claim
125 words
A power converter, comprising: a transformer having a primary winding and a secondary winding; first and second power switches coupled between a converter input and said primary winding to impress an input voltage thereacross; and a voltage clamp circuit for resetting said transformer, including: first and second reset windings coupled between said first and second power switches, first and second energy storage devices coupled between said primary winding and said first and second reset windings, respectively, and first and second switching circuits, coupled to said first reset winding and said second reset winding, respectively, that provide an electrical path from said primary winding to said converter input through said first and second reset windings, respectively, when said first and second power switches are not conducting.
Claim 19
Dependent Claim
17 words
The power converter as recited in claim 15 wherein said first and second storage devices are capacitors.
Claim 20
Dependent Claim
22 words
The power converter as recited in claim 15 wherein said first and second switching circuits each comprise series-coupled first and second diodes.
Claim 21
Dependent Claim
44 words
The power converter as recited in claim 15 wherein said first and second switching circuits each comprise a diode coupled between said first energy storage device and said first reset winding and between said second energy storage device and said second reset winding, respectively.
Claim 22
Dependent Claim
20 words
The power converter as recited in claim 15 wherein said first and second reset windings have identical numbers of turns.
Claim 23
Dependent Claim
25 words
The power converter as recited in claim 15 wherein a maximum duty cycle of said first and second power switches is less than about 0.67.
Claim 24
Dependent Claim
19 words
The power converter as recited in claim 15 wherein said first and second storage devices are of equivalent capacity.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2002-03-15 | 2002-09-14 | 2003-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-03-15 | 2006-09-14 | 2007-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-03-15 | 2010-09-14 | 2011-03-16 | $7700.00 | Window Closed / Lapsed |