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:
Jun. 10, 2003
Filed:
Sep. 14, 2001
Stefan Zudrell-Koch, Dornbirn, AT;
Günter Marent, Dornbirn, AT;
TridonicAtco GmbH & Co. KG, Dornbirn, AT;
Abstract
An electronic ballast for at least one gas discharge lamp (LA) comprises a rectifier circuit ( ) connectable to an a.c. voltage source (U ), a smoothing circuit ( ), connected to the output of the rectifier circuit ( ), for generating an intermediate circuit voltage (U ), and an inverter ( ) fed with the intermediate circuit voltage (U ), at the output of which inverter a connection for the load circuit ( ) containing the lamp (LA) is connected. The smoothing circuit ( ) is constituted by a switching regulator and the ballast further has a control circuit ( ) which detects the intermediate circuit voltage (U ) and controls a controllable switch (S ) of the switching regulator in dependence upon the value of the intermediate circuit voltage (U ). In order to suppress the occurrence of harmonics and disruptive frequencies the control circuit ( ) further detects an input voltage (U ) of the smoothing circuit ( ) and extends the on-state times for the controllable switch (S ) when the input voltage (U ) approaches its minimal value.