Patent US5448469A successfully refreshed from Google Patents.
US5448469A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switch mode power supply with output feedback isolation
Assignee: Deutsche Thomson Brandt GmbH
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Filing: 1994-03-09
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Granted: 1995-09-05
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Expires: 2014-03-09
Abstract
Abstract A switch mode power supply includes a transformer and a switching transistor for turning the primary of the transformer on and off. The secondary of the transformer is connected to a comparator which compares the output voltage to a reference voltage and provides a reverse current to the switching transistor to control the duty cycle of the switching transistor in accordance with the comparison.
Inventors
- 👤 Gerard Rilly
- 👤 Jose Rodriquez-Duran
- 👤 Kim-Ly Kha
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:42
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33569; H01; H01F; H01F38/00; H01F38/50; H02M3/33507; H02M3/33523
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
109 words
A switch mode power supply comprising a transformer having a primary winding and a secondary winding switching means for coupling a DC source to said primary winding, rectifying means coupling said secondary winding to a load, unidirectional coupling means poled opposite to said rectifying means for passing a reverse current, representative of the voltage applied to said load, through said secondary winding, and means for controlling said switching means in response to said reverse current, said means for controlling said switching means comprising a winding of said transformer coupled through a switch and a rectifier to said switching means, said switch being conductive only during a predetermined time window.
Claim 2
Dependent Claim
109 words
A switch mode power supply comprising a transformer having a primary winding and a secondary winding switching means for coupling a DC source to said primary winding, rectifying means coupling said secondary winding to a load, unidirectional coupling means poled opposite to said rectifying means for passing a reverse current, representative of the voltage applied to said load, through said secondary winding, and means for controlling said switching means in response to said reverse current, said means for controlling said switching means comprising a winding of said transformer coupled through a switch and a rectifier to said switching means, said switch being conductive only during a predetermined time window.
Claim 3
Dependent Claim
24 words
The power supply of claim 1, in which said time window has a predetermined temporal position within the operating cycle of said switching means.
Claim 4
Dependent Claim
22 words
The power supply of claim 1, in which said time window is approximately 10-20% of the operating cycle of said switching means.
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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) | 1998-09-04 | 1999-03-06 | 1999-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-04 | 2003-03-06 | 2003-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-04 | 2007-03-06 | 2007-09-05 | $7700.00 | Window Closed / Lapsed |