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:
Nov. 23, 1999
Filed:
Mar. 02, 1998
Milan M Jovanovic, Blacksburg, VA (US);
Laszlo Huber, Blacksburg, VA (US);
Delta Electronics, Inc., Taipei, TW;
Abstract
A new single stage, single switch input current shaping circuit features substantially reduced turn-on switching losses of the switch in the flyback-converter. In this technique, the turn-on switching losses due to the discharge of the output capacitance of the switch are reduced by turning on the switch when its voltage is minimal or close to the minimal. To achieve the turn-on loss reduction for a wide range of line and load conditions, the flyback-converter stage is continuously operated at the boundary of the CCM and DCM by employing a variable-frequency control. In this technique the boost inductor can work either in the DCM or the CCM. The wide-bandwidth, variable-frequency control is implemented by detecting the onset of the DCM/CCM boundary and, subsequently, turning the switch on at the minimum switch voltage. The switch is turned off when the increasing primary current reaches a reference level set by the output-voltage feedback control circuit.