Abstract: A head IC amplifies an output of a read head including MR elements and an ADC converts the amplified output into a digital value. When a CPU performs a head load operation to load a composite head including the read head onto a data area of a disk medium from a ramp, the CPU receives the output of the read head amplified by the head IC as a detection result of an external magnetic field applied to an HDD. The CPU determines whether the head load operation is performed or inhibited based on the received, amplified output of the read head, that is, the detection result of the external magnetic field applied to the HDD.

Abstract: A 2-axis acceleration sensor has two detection axes (X- and Y-axes), and detects a dynamic acceleration (shock) and a static acceleration (a change in gravity or tilt). A sensor output extraction unit acquires detection signals corresponding to the static acceleration for respective detection axes by extracting frequency components lower than a frequency component associated with the dynamic acceleration. A CPU determines whether the disk drive is dropping, whether it has a tilt, and so forth, based on the acquired detection signals for respective detection axes, and causes a magnetic head to be retracted to the position of a ramp if such state is detected.

Abstract: A head suspension assembly in which a trace having a written pattern is disposed on an arm and a suspension. A slider with a magnetic head formed thereon, and a head amplifier IC are mounted on the wiring pattern. An under fill is injected between the head amplifier IC and the wiring pattern, and an outer surface of the head amplifier IC is coated with a resin.

Abstract: A 2-axis acceleration sensor has two detection axes (X- and Y-axes), and detects a dynamic acceleration (shock) and a static acceleration (a change in gravity or tilt). A sensor output extraction unit acquires detection signals corresponding to the static acceleration for respective detection axes by extracting frequency components lower than a frequency component associated with the dynamic acceleration. A CPU determines whether the disk drive is dropping, whether it has a tilt, and so forth, based on the acquired detection signals for respective detection axes, and causes a magnetic head to be retracted to the position of a ramp if such state is detected.

Abstract: A head IC amplifies an output of a read head including MR elements and an ADC converts the amplified output into a digital value. When a CPU performs a head load operation to load a composite head including the read head onto a data area of a disk medium from a ramp, the CPU receives the output of the read head amplified by the head IC as a detection result of an external magnetic field applied to an HDD. The CPU determines whether the head load operation is performed or inhibited based on the received, amplified output of the read head, that is, the detection result of the external magnetic field applied to the HDD.

Abstract: A head suspension assembly for use in a magnetic disk drive includes a magnetic head constituted by a magnetoresistive element for reading data and a head element for writing data, a slider for holding the magnetic head above a surface of a rotating magnetic recording medium, a suspension for supporting the slider, and a head integrated circuit mounted on the suspension. The head integrated circuit having a built-in protection circuit electrically connected with the magnetoresistive element to protect the magnetoresistive element from electrostatic breakdown. Thereby, the magnetic head can be efficiently prevented from suffering electrostatic breakdown due to, e.g., electrostatic discharge occurring during the assembly process of incorporating the head suspension assembly into the magnetic disk drive.

Abstract: Disclosed herein is a system for applying a power-supply voltage to the voice coil control circuit provided in a disk drive and designed to drive the head actuator provided in the disk drive. The power supply circuit of the disk drive outputs a voltage that corresponds to the power-supply voltage applied from a host system. A voltage step-up circuit is provided, which increases the output voltage of the power supply circuit. A switching circuit is provided, which selects the increased voltage output from the voltage step-up circuit when a large current needs to be supplied to the voice coil motor incorporated in the disk drive. The switching circuit selects the output voltage of the power supply circuit when a relatively small current needs to be supplied to the voice coil motor.

Abstract: There is disclosed a head suspension assembly in which a trace having a wiring pattern is disposed on an arm and a suspension. A slider with a magnetic head formed thereon, and a head amplifier IC are mounted on the wiring pattern. An under fill is charged between the head amplifier IC and the wiring pattern, and an outer surface of the head amplifier IC is coated with a resin.

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: A hard disk drive includes a housing formed of a conductive material, and mechanical components housed in the housing. An electronic circuit for driving and controlling the mechanical components is housed in the housing. The drive circuit section has an insulating layer coated on the inner surface of the housing, a printed circuit formed on the insulating layer and having a desired pattern, and electronic parts mounted on the printed circuit. The drive circuit section uses the walls of the housing as a support base.

Abstract: In a magnetic recording and reproducing apparatus, in order to prevent the address code data for identifying the cylinder number of a recording medium from producing continuous erase data, address code data with a gray code arrangement is modulated by a predetermined modulation method, and the modulated address code data is recorded on the recording medium. In this case, address clocks are recorded on the recording medium at predetermined intervals by the magnetization change in a predetermined direction. After the address clocks are recorded, the address data are recorded by the magnetization change in a direction opposite to the predetermined direction.

Abstract: In a head driving control apparatus used, for example, in a hard disc drive, a peak detector detects a peak value of a servo signal output from a data head. A CPU detects a thermal off-track distance L of the data head, on the basis of the peak value of the servo signal. When the thermal off-track distance L is within an allowable off-track distance Lw in a data write mode or within an allowable off-track distance Lc in a data read mode, the CPU enables a data write operation or a data read operation. When the thermal off-track distance L is without the allowable off-track distance Lw in the data write mode or without the allowable off-track distance Lc in the data read mode, the CPU prohibits the data write operation or the data read operation.

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: A recorded data reproducing apparatus according to this invention comprises a data pulse generation section, a peak detection section and a control section. The data pulse generation section reads out data written on the cylinder of a recording medium on which a magnetic head is currently positioned. According to received gain data, the data pulse generation section amplifies a signal corresponding to the readout data, and selectively generates data pulse sequence based on the amplified signal. When the amplified signal corresponds to servo data, the peak detection section detects the peak value of the amplified signal. The control section determines whether or not the magnitude of the detected peak value is nearly equal to a predetermined value. If the determination is negative, the control section refers to a gain data table to determine a change amount of the gain data, and supplies the gain data updated based on the change amount of the data pulse generation section.

Abstract: A recorded data reproducing apparatus according to the invention includes a memory section having a gain data table for storing gain data determined in accordance with a cylinder position above a recording medium. Using the data representing the current cylinder position, the optimum gain data is determined from the gain data table, and supplied to a read pulse generator section under control by a control section. With this arrangement, the gain adjusting circuit is simplified, and the gain adjustment process is also simplified.