Abstract: This invention relates to a motor drive control apparatus for using, for example, a spindle motor of a magnetic disk system. The inventioned apparatus achieves a motor drive control apparatus of high efficiencies with eliminating dead loss of power consumption and avoiding switching noises.The inventioned apparatus for controlling revolution drive of a motor comprising a motor including a rotor and a plurality of drive coils for defining number of excitation phases for making the rotor one cycle revolution and a current supply means for supplying a plurality of drive currents in a successive order to the plurality coils from a voltage source directly.

Abstract: A circuit for generating a mirror current is provided, separately from a circuit for supplying a drive current. The mirror current generating circuit generates a mirror current of a predetermined ratio to the generated drive current. A circuit for detecting a current detects the mirror current. On the basis of the detected mirror current, the operation of a predetermined FET is controlled, and the amount of the drive current to be supplied to a motor is controlled. Thus, a decrease in the drive current due to a current source-side voltage loss can be prevented. In addition, power consumption due to current detection can be reduced, and as a result the drive current can be supplied efficiently.

Abstract: When a sensorless spindle motor having a rotor and a plurality of coils is started, a CPU outputs phase control signals to an excitation phase switching circuit to forcibly rotate the rotor. The CPU detects based on rotor position signals from a rotor position detecting circuit whether or not the rotor is rotated in the forced rotation. As a result, when the rotor is not rotated, the CPU retries the forced rotation. In each retried forced rotation, the CPU decreases the rotational speed of an excitation phase of each coil. The CPU may also execute the forced rotation after the rotor is aligned to an arbitrary position. When the rotor is not rotated in the forced rotation, the CPU retries the forced rotation. In each retried forced rotation, the CPU changes the excitation start phase.

Abstract: In a sector servo type hard-disk apparatus, in the case where a recording medium is not manufacture-formatted, gain control data is written/read in/from a CSS zone of the recording medium after power is turned on and before the first seek is executed. The write/read of the gain control data in/from the CSS zone is also executed in accordance with a peak level of an output signal from an AGC amplifier.

Abstract: When a brushless DC (direct current) motor is started to rotate a rotor, a normal current value is set and then a motor drive current corresponding to the set normal current value is supplied to the brushless DC motor. If the brushless DC motor is not started by this motor drive current, the current value to be set is increased at a desired rate, and a motor drive current corresponding to the increased current value is supplied to the brushless DC motor. That is, the motor drive current corresponding to the current value increased at a desired rate is sequentially supplied to the brushless DC motor until the brushless DC motor has started.

Abstract: When a sensorless and brushless DC motor is started, the rotor having a magnet is positioned by first exciting one pair of motor coils and then exciting another pair motor coils. The excitation of the motor coils is repeated until the rotor stops vibrating. Further, the positions of the magnetic poles of the rotor are detected by comparing the back electromotive force produced in each motor coil with the voltage generated in common to all motor coils. The rotation speed of the rotor is acquired from both the positions of the magnetic poles and the one cycle period of a signal representing the position of the rotor. A suitable delay time corresponding to the acquired rotation speed is determined, and the excitation phases are switched in accordance with the suitable delay time.

Abstract: An access controller for a recording medium, said recording medium including a plurality of track blocks, each of which includes a plurality of tracks, including a generating section including a head, for reading out servo patterns recorded on the recording medium, and for generating servo data from the readout servo patterns, the servo patterns being associated with the tracks, a storage section for storing previous position data and movement amount data, the previous block-in position data representing a previous track position of said head in a current track block of the track blocks, and the movement amount data representing a number of tracks between the previous track position and a track position previous to the previous track position, and a determination section for selectively determining in accordance with the servo data current block-in position data from at least one of the servo data generated by the generating section and the previous block-in position data and the movement amount data stored i

Abstract: The magnetic disk apparatus having improved tracking performance, includes a head for accessing a magnetic disk which is rotated, a displacement detector, a head position controller, a table and a controller. The displacement detector detects an amount of displacement of the head from a designated track of the magnetic disk, based on a signal through the head from servo data associated with the designated track and generating displacement data from the displacement amount. The head position controller controls a position of the head in a radial direction of the magnetic disk in response to an input position control instruction. The table stores a plurality of disk-dependent displacement data. The controller reads out disk-dependent displacement data from the table in accordance with the designated track and outputting the position control instruction to the head position controller in accordance with the displacement data from the displacement detector and the disk-dependent displacement data.

Abstract: A magnetic disk driving apparatus comprises a driving section for driving a magnetic head on a destination track, in response to an input drive instruction, a detecting section for detecting peak values of signal components corresponding to servo data read out from the magnetic disk by the magnetic head, and a controller for generating a drive instruction in accordance with a plurality of selected peak values of the detected peak values to output the generated instruction to said driving section.