Patent ID: 6411057
Filing Date: 2002-06-25
Classification: G11B,H02P,Y10S

Abstract:
A disk drive apparatus comprising:head means for reproducing an information signal from a disk; processing means for processing an output signal from said head means and outputting a reproduced information signal; a movable member, having a field part, for driving said disk; three-phase windings; voltage supplying means, including first and second output terminals, for supplying a DC voltage; three first power amplifying means, each one of said three first power amplifying means including a first power transistor for forming a current path between the first output terminal side of said voltage supplying means and one of said three-phase windings; three second power amplifying means, each one of said three second power amplifying means including a second power transistor for forming a current path between the second output terminal side of said voltage supplying means and one of said three-phase windings; altering signal producing means for producing altering signals; first distribution control means for producing first three-phase signals in response to the altering signals from said altering signal producing means so as to determine active periods of said three first power amplifying means, each of the active periods being an active electrical angle larger than 120 degrees, thereby causing at least one of said three first power amplifying means to be in the active period; second distribution control means for producing second three-phase signals in response to the altering signals from said altering signal producing means so as to determine active periods of said three second power amplifying means, each of the active periods being an active electrical angle larger than 120 degrees, thereby causing at least one of said three second power amplifying means to be in the active period; commanding means for outputting a command signal corresponding to a rotational speed of said movable member; and switching operation means for causing at least one power transistor among three of said first power transistors and three of said second power transistors to perform high-frequency switching corresponding to said command signal from said commanding means, said switching operation means including: current detecting means for providing a current detected signal in response to a supply current supplied to said three-phase windings from said voltage supplying means, and switching control means for causing two of said three first power amplifying means to perform high-frequency switching simultaneously in response to said current detected signal and said command signal when said two of said three first power amplifying means alter current paths to said three-phase windings from said voltage supplying means, and causing two of said three second power amplifying means to perform high-frequency switching simultaneously in response to said current detected signal and said command signal when said two of said three second power amplifying means alter current paths to said three-phase windings from said voltage supplying means.