US5754413A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reduced voltage stress asymmetrical DC-to-DC converter using first and second transformers having differing turns ratios
Assignee: Nokia of America Corp
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Filing: 1996-09-06
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Granted: 1998-05-19
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Expires: 2016-09-06
Abstract
Abstract A voltage stress (e.g., reverse voltage stress) in rectifying diodes of, for instance, an asymmetrical DC-to-DC converter is reduced by using a transformer circuit having multiple power transformers with a composite static transfer characteristic. More specifically, the static transfer characteristic is selected to be monotonic in combination with the transformer circuit including two transformers, having independent isolated cores, coupling an input to output of the converter. A primary to secondary winding ratio of each of the two transformers is selected in such a way as to achieve a reduction in reverse voltage in at least one of the rectifying diodes. The reduction in the reverse voltage and, hence, improved efficiency of the rectifier is directly translatable into an increase in a power density of the converter.
Inventors
- 👤 Simon Fraidlin
- 👤 Valery I. Meleshin
- 👤 Rais K. Miftakhutdinov
- 👤 Alexey V. Nemchinov
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:36
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33569; H02M3/33571; H02M3/01
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
145 words
For use in a power converter having a power train couplable to a source of electrical power and further having a rectifier subject to stress during a reverse voltage condition, a transformer circuit, comprising: a first transformer having a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said first transformer further having a first turns ratio (N 1 ), said first transformer passing a first portion of electrical power through said converter; and a second transformer having a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said second transformer further having a second turns ratio (N 2 ), said second transformer passing a second portion of electrical power through said converter, N 1 being different from N 2 to thereby reduce said stress on said rectifier during said reverse voltage condition.
Claim 2
Dependent Claim
145 words
For use in a power converter having a power train couplable to a source of electrical power and further having a rectifier subject to stress during a reverse voltage condition, a transformer circuit, comprising: a first transformer having a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said first transformer further having a first turns ratio (N 1 ), said first transformer passing a first portion of electrical power through said converter; and a second transformer having a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said second transformer further having a second turns ratio (N 2 ), said second transformer passing a second portion of electrical power through said converter, N 1 being different from N 2 to thereby reduce said stress on said rectifier during said reverse voltage condition.
Claim 3
Dependent Claim
26 words
The transformer circuit as recited in claim 1 wherein N 1 and N 2 are selected as a function of an input voltage to said converter.
Claim 4
Dependent Claim
36 words
The transformer circuit as recited in claim 1 wherein said power train is coupled to a control circuit and drive circuit for controlling an activation of at least one power switch associated with said power train.
Claim 5
Dependent Claim
17 words
The transformer circuit as recited in claim 1 wherein said rectifier comprises at least one rectifying diode.
Claim 6
Dependent Claim
29 words
The transformer circuit as recited in claim 1 wherein said rectifier is coupled to an output filter for providing a filtered output voltage at an output of said converter.
Claim 7
Dependent Claim
42 words
The transformer circuit as recited in claim 1 wherein said power train comprises a first and second alternately-conducting power switch having a duty cycle (D) and (1-D), respectively, N 1 and N 2 being selected as a function of D and 1-D.
Claim 8
Dependent Claim
16 words
The transformer circuit as recited in claim 6 wherein said inductor is connected to a diode.
Claim 9
Dependent Claim
46 words
The transformer circuit as recited in claim 6 wherein said primary winding of said first transformer and said primary winding of said second transformer are connected to an inductor thereby enhancing zero voltage switching (ZVS) across at least one of said first and second power switches.
Claim 10
Dependent Claim
22 words
The transformer circuit as recited in claim 8 wherein said inductor comprises a winding thereby providing a regulated voltage in said converter.
Claim 11
Dependent Claim
146 words
For use in a power converter having a power train couplable to a source of electrical power and further having a rectifier subject to stress during a reverse voltage condition, a method for reducing said stress on said rectifier with a transformer circuit, comprising the steps of: passing a first portion of electrical power through a first transformer containing a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said first transformer having a first turns ratio (N 1 ), and passing a second portion of electrical power through a second transformer containing a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said second transformer having a second turns ratio (N 2 ), N 1 being different from N 2 to thereby reduce said stress on said rectifier during said reverse voltage condition.
Claim 12
Dependent Claim
146 words
For use in a power converter having a power train couplable to a source of electrical power and further having a rectifier subject to stress during a reverse voltage condition, a method for reducing said stress on said rectifier with a transformer circuit, comprising the steps of: passing a first portion of electrical power through a first transformer containing a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said first transformer having a first turns ratio (N 1 ), and passing a second portion of electrical power through a second transformer containing a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said second transformer having a second turns ratio (N 2 ), N 1 being different from N 2 to thereby reduce said stress on said rectifier during said reverse voltage condition.
Claim 13
Dependent Claim
28 words
The method as recited in claim 10 further comprising the step of selecting N 1 and N 2 as a function of an input voltage to said converter.
Claim 14
Dependent Claim
33 words
The method as recited in claim 10 further comprising the step of controlling an activation of at least one power switch associated with said power train with a control circuit and drive circuit.
Claim 15
Dependent Claim
16 words
The method as recited in claim 10 wherein said rectifier comprises at least one rectifying diode.
Claim 16
Dependent Claim
23 words
The method as recited in claim 10 further comprising the step of filtering an output voltage of said converter with an output filter.
Claim 17
Dependent Claim
49 words
The method as recited in claim 10 wherein said power train comprises a first and second alternately-conducting power switch having a duty cycle (D) and (1-D), respectively, the method for reducing further comprising the step of selecting N 1 and N 2 as a function of D and 1-D.
Claim 18
Dependent Claim
48 words
The method as recited in claim 15 further comprising the step of enhancing zero voltage switching (ZVS) across at least one of said first and second power switches with an inductor connected to said primary winding of said first transformer and said primary winding of said second transformer.
Claim 19
Dependent Claim
26 words
The method as recited in claim 16 further comprising the step of providing a regulated voltage in said converter with a winding coupled to said inductor.
Claim 20
Dependent Claim
15 words
The method as recited in claim 16 wherein said inductor is connected to a diode.
Claim 21
Dependent Claim
141 words
A power converter, comprising: a power train couplable to a source of electrical power; a rectifier subject to stress resulting from a reverse voltage condition therein; a transformer circuit, comprising: a first transformer having a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said first transformer further having a first turns ratio (N 1 ), said first transformer passing a first portion of electrical power through said converter, and a second transformer having a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said second transformer further having a second turns ratio (N 2 ), said second transformer passing a second portion of electrical power through said converter, N 1 being different from N 2 to thereby reduce said stress on said rectifier during said reverse voltage condition.
Claim 22
Dependent Claim
141 words
A power converter, comprising: a power train couplable to a source of electrical power; a rectifier subject to stress resulting from a reverse voltage condition therein; a transformer circuit, comprising: a first transformer having a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said first transformer further having a first turns ratio (N 1 ), said first transformer passing a first portion of electrical power through said converter, and a second transformer having a primary winding coupled to said power train and a secondary winding coupled to said rectifier, said second transformer further having a second turns ratio (N 2 ), said second transformer passing a second portion of electrical power through said converter, N 1 being different from N 2 to thereby reduce said stress on said rectifier during said reverse voltage condition.
Claim 23
Dependent Claim
25 words
The converter as recited in claim 19 wherein N 1 and N 2 are selected as a function of an input voltage to said converter.
Claim 24
Dependent Claim
16 words
The converter as recited in claim 19 wherein said rectifier comprises at least one rectifying diode.
Claim 25
Dependent Claim
28 words
The converter as recited in claim 19 wherein said rectifier is coupled to an output filter for providing a filtered output voltage at an output of said converter.
Claim 26
Dependent Claim
41 words
The converter as recited in claim 19 wherein said power train comprises a first and second alternately-conducting power switch having a duty cycle (D) and (1-D), respectively, N 1 and N 2 being selected as a function of D and 1-D.
Claim 27
Dependent Claim
45 words
The converter as recited in claim 21 wherein said primary winding of said first transformer and said primary winding of said second transformer are connected to an inductor thereby enhancing zero voltage switching (ZVS) across at least one of said first and second power switches.
Claim 28
Dependent Claim
21 words
The converter as recited in claim 24 wherein said inductor comprises a winding thereby providing a regulated voltage in said converter.
Claim 29
Dependent Claim
15 words
The converter as recited in claim 24 wherein said inductor is connected to a diode.
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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) | 2001-05-18 | 2001-11-17 | 2002-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-18 | 2005-11-17 | 2006-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-18 | 2009-11-17 | 2010-05-19 | $7700.00 | Window Closed / Lapsed |