Patent ID: 6759821
Filing Date: 2004-07-06
Classification: G11B

Abstract:
A disk drive apparatus comprising:head means for at least reproducing a signal from a disk or recording a signal on a disk; processing means for at least processing an output signal from said head means and outputting a reproduced signal, or processing a signal and outputting a recording signal into said head means; a rotor, having a field part which generates field fluxes, for driving said disk; Q-phase windings (Q is an integer of 3 or more); voltage supplying means, including two output terminals, for supplying a DC voltage; Q first power amplifying means, each of said Q first power amplifying means including a first power transistor for forming a current path between one output terminal side of said voltage supplying means and one of said Q-phase windings; Q second power amplifying means, each of said Q second power amplifying means including a second power transistor for forming a current path between the other output terminal side of said voltage supplying means and one of said Q-phase windings; position detecting means for producing a position signal which responds with a rotation of said rotor; and activation operation means for controlling active operation of said Q first power amplifying means and said Q second power amplifying means responding with said position signal of said position detecting means; and that said activation operation means comprises: time measuring means for measuring a time interval T0 which responds with an interval of said position signal; signal producing means for producing at least an activation control signal which responds with an output signal of said time measuring means, thereby controlling an active operation of at least one power amplifying means among said Q first power amplifying means and said Q second power amplifying means responding with said at least an activation control signal; and said signal producing means includes: slope means for producing a slope signal whose cyclic interval responds with said time interval T0 of said time measuring means, said slope signal repeating a slope waveform substantially a plural times during one period of said position signal; and shaping means for producing said at least an activation control signal which varies substantially smoothly in at least one of rising and falling slopes responding with said slope signal.