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. 08, 2004
Filed:
Jun. 26, 2002
Werner Ludorf, Bergen, DE;
TridonicAtco GmbH & Co. KG, Dornbirn, AT;
Abstract
In a circuit configuration to operate a gas discharge lamp (LA) the lamp (LA) is arranged in a full bridge circuit. A control circuit in normal operation actuates the four switches (S -S ) in such a way that it changes over with a first frequency (f ) alternately between a first and a second state (T , T ), whereby in the first state (T ) the two switches (S , S ) of a first bridge diagonal are opened, one switch (S ) of the second bridge diagonal is closed and the other switch (S ) with a second frequency (f ), which is higher than the first frequency (f ), is alternately opened and closed. In the second state (T ) the four switches (S -S ) are actuated in such a way that the lamp (LA) is pole reversed. In a start phase (T ) on the contrary the switch connected to the DC voltage source (S ) of a half-bridge is opened, the second switch (S ) of this half-bridge is closed, and the two switches (S , S ) of the other half-bridge are with a third frequency (f ) alternately opened and closed. As a result reliable lamp starting is rendered possible and at the same time the generation of high-frequent alternating fields in normal operation is reduced.