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:
Aug. 12, 2014
Filed:
May. 04, 2012
Robert C. Newman, Jr., Emmaus, PA (US);
Robert T. Nachtrieb, Emmaus, PA (US);
Robert C. Newman, Jr., Emmaus, PA (US);
Robert T. Nachtrieb, Emmaus, PA (US);
Lutron Electronics Co., Inc., Coopersburg, PA (US);
Abstract
A dimmable ballast circuit for a compact fluorescent lamp controls the intensity of a lamp tube in response to a phase-control voltage received from a dimmer switch. The ballast circuit generates a lamp current through the lamp tube having a substantially constant envelope such that flicker in the lamp tube and electromagnetic interference (EMI) noise on an AC voltage supply are minimized. The dimmable ballast circuit comprises a high speed control circuit characterized by a cutoff frequency much greater than a frequency of a voltage ripple on a bus voltage of the ballast circuit. The dimmable ballast circuit may also comprise a non-linear amplifier circuit amplifying a lamp-current-feedback signal representative of the magnitude of the lamp current through the lamp.