Patent ID: 6563286
Filing Date: 2003-05-13
Classification: H02P

Abstract:
A hard disk drive apparatus having a storage medium and a polyphase brushless motor with a plurality of field coils, the apparatus comprising a motor driver unit for controlling the polyphase brushless motor, said motor driver unit including a semiconductor integrated circuit for drive control of the polyphase brushless motor, said semiconductor integrated circuit comprising:a phase current output circuit for generating a current which passes through respective field coils of said motor; output terminals for outputting a current which passes through field coils of respective phases of said motor, said current being generated by said phase current output circuit; a phase switching control circuit capable of controlling said phase current output circuit to cause a current passing through one pair of field coils to instead pass through another pair of field coils of said motor for constant-speed rotation thereof and, when starting said motor, said phase switching control circuit being capable of controlling said phase current output circuit to conduct a pulse current, having such a duration as to not cause the rotor to react, to each of a plurality of field coil pairs of said motor alternately in first and second, mutually opposite, directions sequentially; an induced voltage detecting circuit, connected to said phase current output circuit, for detecting first and second voltages induced in each of said field coils of a non-conducting phase by said pulse current in said two directions; an integrating circuit for generating a rotor position signal by integrating said first induced voltage by said pulse current in said first direction and then integrating said second induced voltage by said pulse current in said second direction at each of said field coils of the non-conducting phase to provide a sum of results of the integration of said first and second induced voltages; a polarity detecting circuit for generating a polarity signal representing a polarity of a rotor position signal generated by said integrating circuit at each of said field coils of the non-conducting phase; a memory circuit for storing polarity data representing a plurality of polarity signals generated by said polarity detecting circuit; and a discriminating circuit for determining a field coil pair for current conduction to start said motor on the basis of multiple pieces of polarity data stored in said memory circuit and generating a phase selection setting signal to be supplied to said phase switching control circuit, each of said circuits and said output terminals being formed on a single semiconductor chip.