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:
Sep. 27, 1994
Filed:
Jul. 23, 1993
Magdy Megeid, Zurich, CH;
RCA Thomson Licensing Corporation, Princeton, NJ (US);
Abstract
A pulse-width modulator controls a switching transistor. The switching transistor is coupled to a primary winding of a chopper transformer. The switching transistor and the primary winding are referenced to a nonisolated ground conductor. To initiate a standby mode of operation, a first on/off control signal that is referenced to an isolated ground conductor disables a horizontal oscillator that is energized from a secondary winding of the chopper transformer and that is also referenced to the isolated ground conductor. As a result, a decrease loading of circuit elements that are referenced to the isolated ground occurs. In the standby mode, current pulses in the primary winding are produced at a substantially higher frequency than in normal operation. A frequency detector referenced to the nonisolated ground generates a second on/off control signal that is referenced to the nonisolated ground in accordance with the frequency of the current pulses in the chopper transformer. In this way, the second on/off control signal is generated without the need for an additional isolation element other than the chopper transformer.