Abstract: A dimming ballast system wherein the light output of the lamp is controlled by a remote source. The ballast output voltage is regulated by a voltage control feedback loop, the dimming function being achieved by varying the set point of the control loop. The remote control signal, coded by interrupting the current flow to the ballast for a short period, is processed digitally by a microcomputer which generates information to vary the control set point. Circuit means are provided to control the filament voltage of the fluorescent lamps such that as the lamps are dimmed down, the filament voltage is maintained or slightly increased, thus prolonging lamp life and stabilizing the lamp light output.
Type:
Grant
Filed:
August 13, 1990
Date of Patent:
April 21, 1992
Assignee:
Electronic Ballast Technology, Inc.
Inventors:
Feng-Kang Hu, Chung M. Lau, Kevin Yang, Joshua S. Zhu, Peter S. Shen, Thomas C. Jednacz
Abstract: A dimming ballast system wherein the light output of the lamp is controlled by a remote source. The ballast output voltage is regulated by a voltage control feedback loop, the dimming function being achieved by varying the set point of the control loop. The remote control signal, coded by interrupting the current flow to the ballast for a short period, is processed digitally by a microcomputer which generates information to vary the control set point. Circuit means are provided to control the filament voltage of the fluorescent lamps such that as the lamps are dimmed down, the filament voltage is maintained or slightly increased, thus prolonging lamp life and stabilizing the lamp light output.
Type:
Grant
Filed:
August 13, 1990
Date of Patent:
November 26, 1991
Assignee:
Electronic Ballast Technology, Inc.
Inventors:
Feng-Kang Hu, Chung M. Lau, Kevin Yang, Joshau S. Zhu, Peter S. Shen, Thomas C. Jednacz