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. 29, 1990
Filed:
Nov. 14, 1988
Giovanni M Leonardi, Zurich, CH;
RCA Licensing Corporation, Princeton, NJ (US);
Abstract
An input supply voltage is coupled via a primary winding of a flyback transformer to a collector of a chopper transistor switch that operates at a given frequency. During a portion of each period when the chopper transistor switch is conductive, a second switch applies a short-circuit across a secondary winding of the transformer at a controllable instant that causes the emitter current of the chopper transistor switch to increase at a significantly higher rate. When the emitter current exceeds a predetermined threshold level, a one-shot arrangement is triggered. Consequently, a pulse is produced that turns off the chopper transistor switch and that maintains it nonconductive for the duration of the pulse. A flyback pulse produced in a winding of the transformer is rectified to produce a DC output supply voltage. The length of the interval when the chopper transistor switch is conductive is controlled by the second switch in accordance with the level of the output supply voltage in a negative feedback manner for regulating the output supply voltage.