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:
May. 13, 2008
Filed:
Apr. 21, 2003
John Barrett George, Carmel, IN (US);
John Barrett George, Carmel, IN (US);
Thomson Licensing, Boulogne Billancourt, FR;
Abstract
A dynamic focus amplifier for generating a dynamic focus voltage for a focus electrode for a cathode ray tube at a capacitive load includes a source of a periodic signal at a horizontal deflection frequency. A pull-down transistor is responsive to the periodic signal and coupled to the capacitive load for producing, in accordance with the periodic signal, a first portion of the dynamic focus voltage that decreases, during a first portion of a period of the periodic signal. A storage capacitor is coupled to the capacitive load for replenishing a charge stored in the storage capacitor from a charge stored in the capacitive load to develop a control voltage in the storage capacitor. A pull-up transistor is responsive to the control voltage and coupled to a source of a high voltage and to the capacitive load for producing from the high voltage a current that is coupled to the capacitive load. The current develops a second portion of the dynamic focus voltage that increases, during a second portion of the period of the periodic signal, and stores the charge in the capacitive load.