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. 07, 1981
Filed:
Nov. 13, 1978
George A Cavigelli, Lexington, MA (US);
American Optical Corporation, Southbridge, MA (US);
Abstract
A self-oscillating, high voltage DC power supply for a cathode ray tube drive. Included within the high voltage power supply are an oscillator coil connected to a DC supply and transistor switching means connected to the coil between the coil and ground so as to provide a charging circuit for the oscillator coil. Diode means and output filter are connected between the coil and the DC output to provide a smoothing of the ripple of the DC output. Included in the oscillator power supply are a feedback coil inductively coupled to the oscillator coil and wound in the opposite direction. The feedback coil is a part of a base drive circuit for the transistor switch. Included also are feedback resistance in series with the coil and these elements are connected between the base of the switching transistor and ground. The feedback coil operates to open the switch by means of current induced in the base drive circuit when the current in the feedback circuit reaches a predetermined level related to the current in the oscillator coil primary and thus the transistor. The feedback value is selected such that when the transistor switch reaches its saturation limit, it is shut down to prevent any further large currents therethrough which might damage the device and ultimately the cathode ray tube or any other components connected in the high voltage drive circuit. Preferred embodiments of the invention include high voltage regulation in conjunction with the self-oscillating DC drive.