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. 02, 1996
Filed:
Apr. 14, 1994
James F Mayrand, Townsend, MA (US);
James Gregorich, Merrimack, NH (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
A high-power-factor power supply has a full-wave rectifier for rectifying an AC line voltage, a power regulator including switch means responsive to a control signal for controlling the application of the rectifier output to a load; and a control circuit for producing a switching control signal. The control signal includes a pair of AC line detectors: a first connected in a closed-loop automatic gain control arrangement, and the other connected in an open-loop arrangement. The control circuit initially produces a CURRENT DEMAND REFERENCE signal that is directly related to the difference between the power supply DC output voltage and a self-generated constant reference, and to the waveform shape of the AC line voltage, and is inversely related to magnitude changes of the AC line voltage. The control signal then produces the switching control signal in response to both the CURRENT DEMAND REFERENCE signal and the current flowing in the power supply. The invention avoids the square law dependency of prior art high-power-factor power supplies, can operate over a broad input dynamic range, and is 'self-biasing' in that the power supply itself generates any needed reference voltages.