The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 24, 1998
Filed:
Jun. 27, 1996
Charles R Sullivan, Berkeley, CA (US);
Scott R Jurell, Mertztown, PA (US);
David G Luchaco, Macungie, PA (US);
Lutron Electronics Co., Inc., Coopersburg, PA (US);
Abstract
A dimming control circuit provides power from an ac source to a compact fluorescent lamp. The circuit generally includes a resonant half-bridge inverter driven by a pulse-duration-modulated voltage, for providing a high-frequency ac voltage between the lamp electrodes. A combination inductive and capacitive snubber circuit reduces switching losses in the inverter and increases the efficiency of the dimming circuit. A low-voltage transformer connected across the resonant portion of the inverter provides voltage to heat the lamp filaments. The filament voltage is substantially constant over a range of pulse-durations providing a dimming range from about 100% to 1% of full light output. A power supply circuit having a power factor of about 0.95 provides both high-voltage and low-voltage dc power to the dimming circuit with minimal losses. A shutdown circuit is provided to shut off power to the lamp if the dimming circuit is miswired or a ground fault occurs.