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. 14, 2000
Filed:
Jun. 09, 1997
Applicant:
Inventors:
Hakan Andersson, Malmo, SE;
Johan Uggmark, Lund, SE;
Assignee:
Telefonaktiebolaget LM Ericsson, Stockholm, SE;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B / ;
U.S. Cl.
CPC ...
363 97 ; 363 40 ; 363 56 ; 3151693 ; 3152 / ;
Abstract
An inverter circuit (10) for driving an electroluminescent lamp (14) reduces humming noise by discharging the electroluminescent lamp (14) through a resistor circuit (32). A charging circuit (36 or 38) charges the electroluminescent lamp (14) to a first voltage level during a charge cycle. The electroluminescent lamp (14) is subsequently discharged to a second voltage level through the resistor circuit (32), which prolongs the transition from the first voltage level to the second voltage level, thereby reducing the humming noise components of the inverter circuit (10).