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:
Apr. 23, 2002
Filed:
Aug. 18, 1999
Applicant:
Inventor:
Michael J. DeLurio, Campbell, CA (US);
Assignee:
Sipex Corporation, Billerica, MA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B 3/700 ;
U.S. Cl.
CPC ...
H05B 3/700 ;
Abstract
A method and circuit for generating a voltage waveform across a capacitive load such as an electroluminescent device is described. The method includes the steps of charging and discharging the capacitive load using a constant current source. By sequentially performing the steps of providing a constant current through the capacitive load, eliminating the current, and discharging the capacitive load, a trapezoidal voltage waveform is achieved. In portable telephones and laptop computers with electroluminescent displays, the trapezoidal waveform results in reduced audible noise and power consumption.