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:
Aug. 03, 1999
Filed:
Sep. 20, 1996
Abraham L Melse, Nijmegen, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
A power supply circuit, particularly a flyback converter, comprises a transformer having a secondary winding that powers a load device and/or a rechargeable battery via a rectifier diode. The secondary winding is short circuited by means of a switch connected in series with a diode. The short-circuit is detected by a measurement circuit comprising a measurement winding and a comparator which compares the amplitude variation of the voltage across the measurement winding with a threshold voltage. When a short-circuit is detected a control circuit for the control of the switching transistor of the flyback converter is changed over to a mode in which a given small current is supplied, which flows almost exclusively through the switch. As soon as the short-circuit ends the flyback converter resumes its normal mode of operation. If desired, the load device can control the desired current and/or voltage for powering the load device and charging the battery by turning on and turning off the switch.