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US4866367A
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Multi-loop control for quasi-resonant converters
Assignee: Virginia Tech Intellectual Properties Inc
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Filing: 1988-04-11
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Granted: 1989-09-12
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Expires: 2008-04-11
Abstract
Abstract A multi-loop controller for controlling a quasi-resonant converter having a power switch, a filter inductor and an output voltage. The controller includes a sensor circuit for sensing the output voltage of the converter. A detector monitors the filter inductor current of the converter. The output voltage is compared with a known reference voltage to develop a control error voltage when the output voltage exceeds the reference voltage. A comparing circuit then compares the inductor current with the control error voltage and produces a control signal when a predetermination relationship has been detected. Finally, an activating circuit responsive to the control signal turns the power switch on.
Inventors
- 👤 Raymond B. Ridley
- 👤 Fred C. Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:51
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33507; H02M3/02; H02M3/04; H02M3/10; H02M3/145; H02M3/155; H02M3/156; H02M3/1563; Y; Y02; Y02B; Y02B70/00; Y02B70/10
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
103 words
A multi-loop controller/for controlling a quasi-resonant converter having a power switch, a filter inductor and an output voltage, said controller comprising: means for sensing the output voltage of said converter; means for detecting the filter inductor current; referencing means for comparing said output voltage with a known reference voltage to develop a control error voltage when said output voltage exceeds said reference voltage; comparing means for comparing said inductor current with the output of said referencing means and producing a control signal when a predetermination relationship has been detected; and activating means responsive to said control signal for turning the power switch on.
Claim 2
Dependent Claim
103 words
A multi-loop controller/for controlling a quasi-resonant converter having a power switch, a filter inductor and an output voltage, said controller comprising: means for sensing the output voltage of said converter; means for detecting the filter inductor current; referencing means for comparing said output voltage with a known reference voltage to develop a control error voltage when said output voltage exceeds said reference voltage; comparing means for comparing said inductor current with the output of said referencing means and producing a control signal when a predetermination relationship has been detected; and activating means responsive to said control signal for turning the power switch on.
Claim 3
Dependent Claim
23 words
The controller of claim 1, wherein said predetermined relationship is the intersection of the down-slope of said inductor-current and said control error voltage.
Claim 4
Dependent Claim
43 words
The controller of claim 1, wherein said activating means comprises: a buffer driver means for converting said control signal produced by said comparing means into a constant on-time pulse; and switching means responsive to said buffer driver means for closing said power switch.
Claim 5
Dependent Claim
22 words
The controller of claim 1, wherein said detecting means comprises means for directly detecting the filter inductor current through said filter inductor.
Claim 6
Dependent Claim
48 words
The controller of claim 1, wherein said detecting means comprises transformer means having a primary winding in series with a circuit element other than said filter inductor, said inductor current passing through said circuit element, and a secondary winding in circuit with an input of said comparing 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) | 1992-09-11 | 1993-03-13 | 1993-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-11 | 1997-03-13 | 1997-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-11 | 2001-03-13 | 2001-09-12 | $7700.00 | Window Closed / Lapsed |