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:
Jul. 28, 1987
Filed:
Nov. 12, 1986
James D Bucher, II, St. Paul, MN (US);
Zytec Corporation, Eden Prairie, MN (US);
Abstract
An off-line switching power supply is described which controls the switching transistor of a fly-back circuit in such a fashion as to achieve better than 0.99 power factor control. The technique used for power factor control allows the switching power supply to operate either from AC or DC sources. The power supply operating from an AC source will accept all international voltages and line frequencies as input to produce a well-regulated DC output. The inductor of the fly-back circuit is maintained at the verge of continuous/discontinuous operation by the power factor control circuit to achieve a high efficiency operation and to minimize switching losses. The power factor correction circuit uses pulsewidth modulation and frequency modulation to control the switching transistor and maintain a high power factor under varying line and load conditions. The power supply also includes integral current limiting protection and RFI filtering for safe and quiet operation.