Automatic energy control lighting system with automatically variable dc source
First Claim
1. In combination with a high intensity gas discharge lamp, a dimmer circuit for controlling the brightness thereof comprising:
- ballast means connected to the lamp and connectable to an ac power distribution line;
said ballast means including a reactor portion;
gated bypass means for providing at least partial bypass of current around said reactor portion of said ballast means;
controllable gate source voltage means operably connected to said gated bypass means for controllably rendering said gated bypass means conductive, and thereby bypassing said reactor portion of said ballast means; and
a capacitor connected across the lamp to prevent extinguishing of the lamp during rapid and sudden dimming.
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Accused Products
Abstract
An automatically variable d.c. voltage source supplies a control signal to a dimmer circuit that controls the brightness of a high intensity gas discharge lamp in response to a varying d.c. voltage. The automatically variable d.c. voltage source produces a varying d.c. voltage at its output which is functionally related to the difference between a voltage from a stable reference voltage source and a voltage produced by a photocell circuit which is responsive to the light level of an area illuminated by the lamp controlled by the dimmer circuit. The variable d.c. source includes circuitry for indicating relamping conditions.
72 Citations
22 Claims
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1. In combination with a high intensity gas discharge lamp, a dimmer circuit for controlling the brightness thereof comprising:
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ballast means connected to the lamp and connectable to an ac power distribution line; said ballast means including a reactor portion; gated bypass means for providing at least partial bypass of current around said reactor portion of said ballast means; controllable gate source voltage means operably connected to said gated bypass means for controllably rendering said gated bypass means conductive, and thereby bypassing said reactor portion of said ballast means; and a capacitor connected across the lamp to prevent extinguishing of the lamp during rapid and sudden dimming.
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2. An automatic energy control lighting system for maintaining substantially constant illumination over a work area with time, comprising:
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one or more lamps for projecting light over a work area; an electrical signal source generating a bias signal that is automatically variable in response to changes in the total illumination level over the work area as detected by a photocell circuit; a buffer circuit to convert the variable bias signal to a higher signal level, said buffer circuit having means for regulating the rate of change of the higher level signal to provide a system to prevent rapid changes thereof in response to transient ambient stimuli; and power control means for adjusting the power supplied to said lamps in response to the higher level signal to alter the light output of said lamps to maintain substantially constant illumination of the work area over time. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An automatically variable d.c. voltage source suitable for use with a lamp dimmer circuit that adjusts the light output of a lamp illuminating a work area in response to a variable d.c. bias, comprising:
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a reference signal source producing a stable, continuous electrical signal level representative of a level of illumination desired over a work area; photocell circuit means for detecting the level of illumination produced by a light source over a work area and producing a variable level signal representative of the level of illumination over the work area; amplifier means connected to said reference signal source and said photocell circuit means for automatically producing a variable d.c. bias signal functionally related to the difference between the level of illumination over the work area and the desired illumination level for the work area; and a buffer circuit to convert said variable d.c. bias signal to a higher signal level, said buffer comprising a controlled current source having a capacitor at its output to form an integrator that regulates the rate of change of the higher level d.c. bias signal to prevent rapid changes thereof in response to transient ambient stimuli. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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Specification