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. 03, 1991
Filed:
Sep. 06, 1989
Shigetoshi Higaki, Tokyo, JP;
Yoshitaka Hata, Kawasaki, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
In a PWM control type power supply apparatus, a modulation (high frequency) signal component is eliminated from an AC output. The PWM control type power supply apparatus includes: AC-to-DC converting means coupled to an AC (alternating current) power source capable of supplying a first AC voltage having a low frequency from a pair of output terminals, for converting the first AC voltage to obtain a positive DC (direct current) voltage from a positive half cycle of the first AC voltage appearing at one output terminal and a negative DC voltage from a negative half cycle of the first AC voltage appearing at one output terminal with a common voltage appearing at the other output terminal; and, DC-to-AC inverter means including a pair of first and second switching elements, and a PWM (pulse width modulation) controller for controlling switching operations of the first and second switching elements in a PWM control mode so as to invert the positive and negative DC voltage into a second AC voltage having a modulation frequency higher than the low frequency with respect to the common voltage output terminal, whereby the second AC voltage contains no modulation frequency component.