US5648702A
Expired / Lapsed
US
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Dimming control circuit having feedback frequency control
Assignee: Fairchild Korea Semiconductor Ltd
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Filing: 1995-11-13
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Granted: 1997-07-15
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Expires: 2015-11-13
Abstract
Abstract A feedback dimming control circuit for controlling the luminance of a plurality of lamps, the circuit comprising: a multiplier receiving and multiplying a feedback current and an input voltage, a first subtracter generating an error signal by subtracting an output voltage from the multiplier from a reference voltage, a second subtracter subtracting a signal responsive to the error signal from the input voltage, an oscillator generating a periodic signal in response to the output of the second subtracter; and a tank resonating in response to the periodic signal and generating the feedback current.
Inventors
- 👤 Nak-Choon Choi
- 👤 Kyung-Ha Jee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:04
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/36; H05B41/38; H05B41/39; H05B41/392; H05B41/3921; H05B41/3925; Y; Y10; Y10S; Y10S315/00; Y10S315/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
108 words
A feedback dimming control circuit for controlling the luminance of a plurality of lamps, the circuit comprising: a multiplier receiving and multiplying a feedback signal and an input voltage to generate a first output signal; a first subtracter generating an error signal by subtracting the first output signal from a reference voltage; a second subtracter subtracting a signal responsive to the error signal from the input voltage to generate a second output signal; an oscillator generating a periodic signal in response to the second output signal; and, a tank resonating in response to the periodic signal, generating the feedback signal, and supplying power to the plurality of lamps.
Claim 2
Dependent Claim
108 words
A feedback dimming control circuit for controlling the luminance of a plurality of lamps, the circuit comprising: a multiplier receiving and multiplying a feedback signal and an input voltage to generate a first output signal; a first subtracter generating an error signal by subtracting the first output signal from a reference voltage; a second subtracter subtracting a signal responsive to the error signal from the input voltage to generate a second output signal; an oscillator generating a periodic signal in response to the second output signal; and, a tank resonating in response to the periodic signal, generating the feedback signal, and supplying power to the plurality of lamps.
Claim 3
Dependent Claim
43 words
The feedback dimming control circuit of claim 1, further comprising: an error signal amplifier receiving and amplifying the error signal from the first subtracter; and an inverter inverting the amplified error signal and providing an inverted amplified error signal to the second subtracter.
Claim 4
Dependent Claim
42 words
The feedback dimming control circuit of claim 2, further comprising: an adder summing an applied dimming signal and the first output signal; wherein the first subtracter generates the error signal by subtracting an output siqnal from the adder from the reference voltage.
Claim 5
Dependent Claim
38 words
The feedback dimming control circuit of claim 3, wherein the dimming signal varies according to a change in the number of lamps in the plurality of lamps, such that luminance control of the plurality of lamps is maintained.
Claim 6
Dependent Claim
27 words
The feedback dimming control circuit of claim 1, wherein the reference voltage increases proportionally with an increase in the number of lamps in the plurality of lamps.
References Cited (Backward Citations)
US4933605A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-14 | 2001-01-13 | 2001-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-14 | 2005-01-13 | 2005-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-14 | 2009-01-13 | 2009-07-15 | $7700.00 | Window Closed / Lapsed |