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. 20, 1994
Filed:
Jul. 23, 1993
Magdy Megeid, Zurich, CH;
RCA Thomson Licensing Corporation, Princeton, NJ (US);
Abstract
In a switch mode power supply, a full wave rectified AC mains supply voltage is produced from an AC mains supply voltage without low-pass filtering. The unfiltered rectified voltage is applied to a winding of a flyback transformer that is coupled to a switching transistor. A first plurality of current pulses are generated in the winding from the rectified voltage at a frequency that is higher than the frequency of the mains supply voltage and at peak amplitudes that vary in accordance with the rectified voltage in a manner to increase a power factor. The rectified voltage is further rectified via a rectifier coupled in series with a resistor and a low-pass filter capacitor and produces current pulses in the capacitor. A voltage in the capacitor is coupled via a second switching transistor to the winding to produce in the winding a second plurality of current pulses that reduce a ripple component at an output of the power supply. The resistor increases the pulse-width and decreases the magnitude of the capacitor current pulses in a manner to reduce input harmonic contents and increase the power factor.