EP0143884A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Energy-saving apparatus for dimming discharge lamps
Assignee: Arex Industries Inc
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Filing: 1984-07-24
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Granted: —
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Expires: 2004-07-24
Abstract
Abstract An apparatus for dimming discharge lamps with minimized power consumption comprises a phase control circuit connected to control the transfer of an A.C. power supply voltage to a combination of a discharge lamp such as a fluorescent lamp and ballast means, acting to transfer the power supply voltage to the lamp only during a portion of each half-cycle of that voltage in the region of the peak value thereof, and to block transfer of this voltage during the remainder of each half-cycle, together with a series resonance circuit which is connected such as to supply a constant low-level current to the lamp circuit during the half-cycle portions which are blocked by the phase circuit. A sufficiently high electrode temperature is thereby maintained to ensure reliable flicker-free operation over a wide range of control phase angles, without wasteful dissipation of energy in heating the lamp.
Inventors
- 👤 Takefumi Hatanaka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 12:43
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/36; H05B41/38; H05B41/39; H05B41/392; H05B41/3921; H05B41/3924
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
205 words
1 . An apparatus for dimming a discharge lamp, adapted to be coupled between a source of an A.C. power supply voltage and a combination of a discharge lamp with ballast means, said apparatus comprising: phase control circuit means for applying said power supply voltage to s,-id discharge lamp and ballast means during conduction intervals each corresponding to a predetermined central portion of a half-cycle of said power supply voltage, and for blocking transfer of said power supply voltage to said discharge lamp and ballast means during the remaining portions of said half-cycle which precede and succeed said central portion, and; a series resonance circuit coupled in parallel with said phase control circuit means between said power supply voltage source and said discharge lamp and ballast means, comprising an inductor and a capacitor, with the values of inductance and capacitance thereof being selected such as to pass a substantially constant preheating current through said discharge lamp and ballast means during each half-cycle of said power supply voltage including said portions thereof in which blocking by said phase control circuit means occurs, said preheating current level being substantially lower than the maximum current which flows in said discharge lamp and ballast means during said conduction intervals.
Claim 2
Dependent Claim
205 words
1 . An apparatus for dimming a discharge lamp, adapted to be coupled between a source of an A.C. power supply voltage and a combination of a discharge lamp with ballast means, said apparatus comprising: phase control circuit means for applying said power supply voltage to s,-id discharge lamp and ballast means during conduction intervals each corresponding to a predetermined central portion of a half-cycle of said power supply voltage, and for blocking transfer of said power supply voltage to said discharge lamp and ballast means during the remaining portions of said half-cycle which precede and succeed said central portion, and; a series resonance circuit coupled in parallel with said phase control circuit means between said power supply voltage source and said discharge lamp and ballast means, comprising an inductor and a capacitor, with the values of inductance and capacitance thereof being selected such as to pass a substantially constant preheating current through said discharge lamp and ballast means during each half-cycle of said power supply voltage including said portions thereof in which blocking by said phase control circuit means occurs, said preheating current level being substantially lower than the maximum current which flows in said discharge lamp and ballast means during said conduction intervals.
Claim 3
Dependent Claim
72 words
An apparatus for dimming a discharge lamp according to claim 1, in which said phase control circuit means comprise a phase control circuit including a electronic switch means for controlling the application of said power supply voltage to said discharge lamp, and a pulse generating circuit for generating control pulses to enable conduction by said electronic switch means, the width of said control pulses thereby determining the width of said conduction intervals.
Claim 4
Dependent Claim
64 words
An apparatus for dimming a discharge lamp according to claim 2, in which said pulse generating circuit comprises a full-wave rectifier circuit coupled to said power supply voltage source for producing a rectified full-wave voltage therefrom, and a level detection circuit "for initiating and terminating each of said control pulses when said full wave voltage waveform exceeds and falls below a predetermined level, respectively.
Claim 5
Dependent Claim
58 words
An apparatus for dimming a discharge lamp according to claim 3, and further comprising externally operable means coupled to said level detection circuit for controlling the detection level thereof, to thereby control the duration of each of said control pulses and thereby control the width of said conduction intervals and hence the illumination level of said discharge lamp.
References Cited (Backward Citations)
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