Patent US3875458A successfully refreshed from Google Patents.
US3875458A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dimmer for discharge lamp utilizing a pulse enabling circuit
Assignee: HARRINGTON RONALD G
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Filing: 1974-06-10
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Granted: 1975-04-01
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Expires: 1994-06-10
Abstract
Abstract A lighting control apparatus (dimmer) responsive to an electrical demand signal to control the portion of the voltage cycle during which voltage is supplied to one or more discharge lamps from AC voltage source, using a pulse enable circuit to provide pulsing of the firing circuit appropriate for discharge lamps. The apparatus comprises a shaping circuit responsive to a demand signal, a timing circuit, a pulse enable circuit, a single pulse per half-cycle firing means, and a solid state switching means. The pulse enable circuit prevents activation of the firing means when the solid state switching means is in a conductive state (firing pulses based on the voltage cycle could otherwise occur before the lagging current of the previous halt has fallen to zero). This combines the advantages of low power consumption of single pulse firing circuits with a reliability of firing of discharge lamps obtained heretofore only in multiple pulse firing circuits.
Inventors
- 👤 George A Kappenhagen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:30
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/36; H05B41/38; H05B41/39; H05B41/392; H05B41/3921; H05B41/3924; Y; Y10; Y10S; Y10S315/00; Y10S315/04
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
233 words
A lighting control apparatus responsive to an electrical demand signal to control the portion of each half cycle during which voltage is supplied to a discharge lamp load from an AC voltage source, said apparatus comprising: a. solid state switching means having gating means and two power terminals, said power terminals being adapted to be connected in series with said load across said AC voltage source; b. a single pulse per half cycle firing means having an output connected to said gating means of said solid state switching means, which firing means renders said solid state switching means conductive when said firing means is initiated; c. a pulse enable circuit means having an output connected to said firing means, for sensing the status of said solid state switching means and preventing the activation of said firing means when said solid state switching means is in a conductive state; d. a timing circuit having an output connected to said pulse enable circuit means, said timing circuit generating a signal, which, when coupled through to the firing means by said pulse enable circuit means, will initiate the firing means to render the solid state switching means conductive; and e. a shaping circuit having an output electrically connected to said timing circuit, said shaping circuit being adapted to receive said demand signal and to generate an output signal which is a function of said demand signal.
Claim 2
Dependent Claim
233 words
A lighting control apparatus responsive to an electrical demand signal to control the portion of each half cycle during which voltage is supplied to a discharge lamp load from an AC voltage source, said apparatus comprising: a. solid state switching means having gating means and two power terminals, said power terminals being adapted to be connected in series with said load across said AC voltage source; b. a single pulse per half cycle firing means having an output connected to said gating means of said solid state switching means, which firing means renders said solid state switching means conductive when said firing means is initiated; c. a pulse enable circuit means having an output connected to said firing means, for sensing the status of said solid state switching means and preventing the activation of said firing means when said solid state switching means is in a conductive state; d. a timing circuit having an output connected to said pulse enable circuit means, said timing circuit generating a signal, which, when coupled through to the firing means by said pulse enable circuit means, will initiate the firing means to render the solid state switching means conductive; and e. a shaping circuit having an output electrically connected to said timing circuit, said shaping circuit being adapted to receive said demand signal and to generate an output signal which is a function of said demand signal.
Claim 3
Dependent Claim
137 words
The apparatus of claim 1, wherein said pulse enable circuit means comprises: a. a transformer having a primary and a secondary, said primary being connected across said power terminals of said solid state switching means; b. a rectifier having an input and an output, said input being connected to said secondary of said transformer; and c. a switching device having an input terminal, an output terminal and a signal terminal, said signal terminal being connected to said rectifier output, said output terminal providing the output of said pulse enable circuit means, and said input terminal being connected to said output of said timing circuit, the rectified signal from said transformer being effective to turn said switching device on when there is voltage across said solid state switching means indicative of said solid state switching means being non-conductive.
Claim 4
Dependent Claim
42 words
The apparatus of claim 2, wherein a reset circuit having an output connected to said timing circuit is included, said reset circuit monitoring the voltage of said AC voltage source and initializing said timing circuit each time said voltage passes through zero.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |