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:
Jan. 20, 2004
Filed:
Feb. 28, 2002
Makoto Gotou, Nishinomiya, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
Power transistors of a power supplying part execute high-frequency switching operation and form current paths to three-phase windings so as to rotate the disk. A voltage detecting part produces a detected pulse signal responding with terminal voltages of the three-phase windings. An activation operation part controls active periods of the power transistors in response to the detected signal. A phase detecting part includes a slant producing part and a phase pulse producing part. The slant producing part produces a slant voltage signal which intermittently responds with a voltage difference between one of the power supplying terminal voltages and the common terminal voltage of the three-phase windings and has a voltage slant. The phase pulse producing part produces a phase pulse signal by comparing the slant voltage signal with a reference voltage. A commanding part produces a command signal which responds with the phase pulse signal. A switching operation block causes at least one of the power transistors to perform high-frequency switching responding with the command signal.