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:
Jul. 27, 2004
Filed:
Sep. 28, 2002
John G. Konopka, Deer Park, IL (US);
Sameer Sodhi, Vernon Hills, IL (US);
Osram Sylvania, Inc., Danvers, MA (US);
Abstract
A ballast ( ) includes an inverter ( ) and a protection circuit that prevents excessive lamp-to-earth-ground fault current. The protection circuit includes a transformer ( ) and an inverter disable circuit ( ). The transformer measures a first current going out of one set of ballast output terminals ( ) and a second current going into another set of ballast output terminals ( ). In response to a substantial imbalance between the first current and the second current, inverter disable circuit ( ) terminates inverter switching. Preferably, protection circuit further includes a restart timer circuit ( ) that, following termination of inverter switching in response to a fault condition, prevents the inverter from restarting for a predetermined delay period.