Patent ID: 6566827
Filing Date: 2003-05-20
Classification: G11B,H02P

Abstract:
A disk drive apparatus comprising:head means for reproducing a signal from a disk; processing means for processing an output signal from said head means and outputting a processed signal; 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; power supplying means having Q first power transistors and Q second power transistors, each of said Q first power transistors forming a current path between one output terminal side of said voltage supplying means and one of said Q-phase windings, and each of said Q second power transistors 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 the rotation of said rotor; activation operation means for controlling active periods of said Q first power transistors and said Q second power transistors responding with an output signal of said position detecting means, each of said active periods being larger than the period of 360/Q electrical degrees; commanding means for producing a command signal which responds with a rotational speed of said disk; and switching operation means for causing at least one of said Q first power transistors and said Q second power transistors to perform high-frequency switching responding with said command signal; and that said switching operation means includes: current detecting means for producing a current detection signal which responds with or corresponds to a composed current to said Q-phase windings from said voltage supplying means, and switching control means for producing a switching pulse signal which responds with said current detection signal and said command signal, and said activation operation means produces at least a slew-rate switching signal which responds with said switching pulse signal at a control terminal side of at least one power transistor among said Q first power transistors and said Q second power transistors, said at least a slew-rate switching signal having a smoothed voltage slope in at least one of rising and falling slopes, and causes said at least one power transistor to follow said at least a slew-rate switching signal, thereby supplying a high-frequency switching drive voltage signal to one terminal of said Q-phase windings, said high-frequency switching drive voltage signal having smoothed voltage slopes and responding with said current detection signal and said command signal.