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US4607320A
Expired / Lapsed
US
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Power supply device having a switched primary power supply and control means for maintaining a constant off period and a variable on period
Assignee: Canon Inc
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Filing: 1984-01-16
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Granted: 1986-08-19
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Expires: 2004-01-16
Abstract
Abstract A power supply device has improved power efficiency and stability for use in a copier or the like. The primary power supply to the device being switched with a constant turned-off period to achieve variable power supply control.
Inventors
- 👤 Toshiro Matui
- 👤 Koji Suzuki
- 👤 Jyoji Nagahira
- 👤 Kunio Yoshihara
- 👤 Kazuyoshi Takahashi
- 👤 Tadashi Ishikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:15
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33507
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
152 words
A power supply device comprising: a transformer for obtaining a desired power from a primary supply power; switching means for switching the power supplied to a primary side of said transformer; detecting means for detecting a current passing through a load connected to a secondary side of said transformer; means for amplifying the difference between a voltage signal corresponding to the current passing through said load and a reference voltage and generating an output signal corresponding to the difference; signal generating means for generating a signal with a sawtooth wave form in accordance with the output signal; and control means for comparing a level of the sawtooth signal from said signal generating means with a reference level and controlling said switching means in accordance with the comparison result, said control means being operable to maintain constant a turned-off period of said switching means and vary a turned-on period of said switching means.
Claim 2
Dependent Claim
152 words
A power supply device comprising: a transformer for obtaining a desired power from a primary supply power; switching means for switching the power supplied to a primary side of said transformer; detecting means for detecting a current passing through a load connected to a secondary side of said transformer; means for amplifying the difference between a voltage signal corresponding to the current passing through said load and a reference voltage and generating an output signal corresponding to the difference; signal generating means for generating a signal with a sawtooth wave form in accordance with the output signal; and control means for comparing a level of the sawtooth signal from said signal generating means with a reference level and controlling said switching means in accordance with the comparison result, said control means being operable to maintain constant a turned-off period of said switching means and vary a turned-on period of said switching means.
Claim 3
Dependent Claim
59 words
A power supply device according to claim 1, wherein said switching means is adapted to turn on and off the power supply to the primary side of said transformer, whereby a sinusoidal voltage wave of a determined frequency appears in said switching means and in the primary side of said transformer during the turned-off period of said switching means.
Claim 4
Dependent Claim
31 words
A power supply device according to claim 1, further comprising rectifying means on the secondary side of said transformer, wherein said load is driven by the output of said rectifying means.
Claim 5
Dependent Claim
30 words
A power supply device according to claim 1, wherein a maximum level of the sawtooth signal from said signal generating means varies according to the output of said detecting means.
Claim 6
Dependent Claim
25 words
A power supply device according to claim 4, wherein the slope of said sawtooth wave is constant regardless of the output of said detecting 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) | 1989-08-18 | 1990-02-17 | 1990-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-18 | 1994-02-17 | 1994-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-18 | 1998-02-17 | 1998-08-19 | $7700.00 | Window Closed / Lapsed |