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. 15, 1995
Filed:
Oct. 02, 1992
Slobodan Cuk, Laguna Hills, CA (US);
Milivoje Brkovic, Pasadena, CA (US);
California Institute of Technology, Pasadena, CA (US);
Abstract
A DC voltage to a load is provided from a rectified AC power line source with unity power factor using Cuk dc-to-dc switching converter, either unisolated or isolated extensions, operated as an automatic current shaper with unity power factor performance. This is obtained by operating the Cuk converter in a discontinuous inductor current mode (DICM) at a constant switching frequency and constant duty ratio without input current feedback control customarily used, but operating in an open-loop fashion. Even though the Cuk converter is operated in DICM, its input current is nonpulsating and flowing throughout the switching cycle, unlike other converters having pulsating input current in DICM, thus reducing input harmonic currents due to switching frequency and its harmonics. Further improvement is obtained and even the remaining ripple in the input current is entirely eliminated to result in ideal, clean, harmonic-free input current waveform with unity power factor performance, when the coupled-inductor and/or integrated magnetics extensions of the Cuk converter conditions are implemented. They could be operated at low to moderate switching frequency, thus providing high efficiency and without the need for additional input filtering customarily used in other converters.