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:
May. 05, 1992
Filed:
Jan. 29, 1991
Shigetoshi Higaki, Tokyo, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
In a PWM control type power supply apparatus, a modulation (high frequency) signal component is eliminated not only from AC input, but also AC output. The PWM control type power supply apparatus includes: an AC-to-DC converting unit capable of supplying a first AC voltage having a source 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 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 another output terminal; a DC-to-AC inverter unit 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 source frequency the second AC voltage being applied to a load; and a choke coil having a single core and first, second and third coil windings wound on the single core for magnetically coupling the coil windings with each other, the first and second coil windings being interposed between the AC power source and the AC-to-DC converting means, and also the third coil winding being interposed between the DC-to-AC inverter unit and the load.