Patent ID: 6291961
Filing Date: 2001-09-18
Classification: G11B,H02P,Y10S

Abstract:
A disk drive apparatus comprising:a head for at least one of reproducing an information signal from a disk and recording an information signal on a disk;processing means for at least one of processing an output signal from said head and outputting a reproduced information signal, and processing an input signal and outputting a recording signal into said head;a movable member, having a field part, for driving said disk;Q phase windings, Q being an integer of three or more;voltage supplying means, including first and second output terminals, for supplying a DC voltage;Q first power amplifying means, each one of said Q first power amplifying means including a first FET power transistor for forming a current path between the first output terminal side of said voltage supplying means and one of said Q-phase windings;Q second power amplifying means, each one of said Q second power amplifying means including a second FET power transistor for forming a current path between the second output terminal side of said voltage supplying means and one of said Q-phase windings;altering signal producing means for producing altering signals;first distribution control means for producing first Q-phase signals in response to the altering signals from said altering signal producing means to determine active periods of said Q first power amplifying means, each of the active periods being an active electrical angle larger than 360/Q degrees, thereby causing at least one of said Q first power amplifying means to be in the active period;second distribution control means for producing second Q-phase signals in response to the altering signals from said altering signal producing means to determine active periods of said Q second power amplifying means, each of the active periods being an active electrical angle larger than 360/Q degrees, thereby causing at least one of said Q second power amplifying means to be in the active period;commanding means for outputting a command signal corresponding to a rotational speed of said disk; andswitching operation means for causing at least one FET power transistor among Q of said first FET power transistors and Q of said second FET power transistors to perform high-frequency switching corresponding to the 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 Q-phase windings from said voltage supplying means, andswitching control means for comparing said current detected signal with an output signal from said commanding means and causing said at least one FET power transistor to perform high-frequency switching in response to the comparison result, one of Q of said first FET power transistors conducting in a half-on state while another of Q of said first FET power transistors conducts in a full-on state in a portion of a period when two of said Q first power amplifying means alter current paths to said Q-phase windings from said voltage supplying means.