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:
May. 30, 2000
Filed:
Sep. 18, 1996
U.S. Philips Corporation, New York, NY (US);
Abstract
A circuit for operating a discharge lamp from input terminals of a low frequency (f) supply voltage source with a rectifier coupled to the input terminals for rectifying the low-frequency supply voltage. A capacitor is coupled to the output of the rectifier. A DC-AC converter is coupled to the capacitor for generating a lamp current which comprises a DC component and a high-frequency AC component, the amplitude of the high-frequency AC component being modulated with a low frequency which is equal to twice the frequency f. An apparatus (V) adjusts the lamp power. The circuit parameters are chosen such that during operation the average amplitude of the high-frequency lamp current component is at least 500 times the amplitude of the low-frequency modulation of the high-frequency lamp current component with the power set for its maximum adjustable value. As a result, the discharge lamp can be dimmed over a wide range without striations occurring.