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:
Mar. 18, 2003
Filed:
Oct. 23, 2001
Applicant:
Inventors:
Marcel Beij, Eindhoven, NL;
Arnold Willem Buij, Eindhoven, NL;
Everaard Marie Jozef Aendekerk, Eindhoven, NL;
Wilhelmus Hinderikus Maria Langeslag, Nijmegen, NL;
Assignee:
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02M 5/447 ; G05F 1/46 ;
U.S. Cl.
CPC ...
H02M 5/447 ; G05F 1/46 ;
Abstract
A ballast circuit comprises an inverter formed by a bridge circuit. The power consumed by a lamp connected to the ballast circuit is controlled by controlling the duty cycles of control signals that drive the bridge switches. The duty cycle is proportional to digital signals generated by a pulse duration modulator included in a microprocessor. To increase the number of settings to which the lamp power can be set, the digital signals are modulated.