Abstract: Disturbances to actuator control caused by external vibrations are corrected using feed-forward techniques that are selectively enabled or disabled based on signal values within a track follow loop. An increase in data integrity and reliability may be achieved by reducing off-track reads and writes caused by physical disturbances to disk drives during operation. Accelerometers detect external forces imparted on a disk and an acceleration feed-forward (AFF) signal is generated to compensate for disturbances to the location of a head caused by such external forces. Application of the AFF signal to an actuator may be based on whether signal values along the track follow loop exceed a certain threshold.

Abstract: Control of micro actuator movement is calibrated in response to a sinusoidal input signal. A response of the micro actuator to the sinusoidal input signal is measured, for example, based on measurement of a change in radial location of a transducer connected to the micro actuator responsive to the sinusoidal input signal. Control of the movement of the micro actuator is calibrated based on the measured response of the micro actuator to the sinusoidal input signal. For example, a gain of a micro actuator control loop that controls movement of the micro actuator may be regulated based on the measured change in radial location of the transducer. Related circuits and devices are also discussed.

Abstract: Control of micro actuator movement is calibrated in response to a sinusoidal input signal. A response of the micro actuator to the sinusoidal input signal is measured, for example, based on measurement of a change in radial location of a transducer connected to the micro actuator responsive to the sinusoidal input signal. Control of the movement of the micro actuator is calibrated based on the measured response of the micro actuator to the sinusoidal input signal. For example, a gain of a micro actuator control loop that controls movement of the micro actuator may be regulated based on the measured change in radial location of the transducer. Related circuits and devices are also discussed.

Abstract: Disturbances to actuator control caused by external vibrations are corrected using feed-forward techniques that are selectively enabled or disabled based on signal values within a track follow loop. An increase in data integrity and reliability may be achieved by reducing off-track reads and writes caused by physical disturbances to disk drives during operation. Accelerometers detect external forces imparted on a disk and an acceleration feed-forward (AFF) signal is generated to compensate for disturbances to the location of a head caused by such external forces. Application of the AFF signal to an actuator may be based on whether signal values along the track follow loop exceed a certain threshold.

Abstract: A method and apparatus are disclosed which are operable to determine a capacitance associated with at least one piezoelectric element in an dual actuator disk drive. The capacitance information is used to adjust a driver used to drive the piezoelectric element. Capacitance is determined by supplying a predetermined current into the piezoelectric element(s) for a predetermined time period. A voltage associated with the piezoelectric element(s) is measured following the predetermined time period. The capacitance of the piezoelectric element(s) is then calculated based on the measured voltage, the current supplied, and the predetermined time period.

Abstract: The present invention relates to a disk drive seek control system which is capable of rapidly moving a transducer from an initial position to a target position above a data storage medium. The system applies control to an actuator motor means based on projected transducer velocity at a future servo sample time rather than velocity at a previous servo sample time. This allows the system to significantly reduce transducer velocity errors relative to a desired velocity profile. In addition, the system utilizes dynamically adapted feed forward deceleration current during a deceleration portion of the seek cycle to further reduce velocity errors during this period. By reducing velocity error during the seek cycle, the system significantly reduces the length of time required for settling the transducer on the target track of the disk after the seek cycle has ended.

Abstract: An electronic architecture that provides a portable hard disk drive that can meet the type II PCMCIA specification and which can efficiently operate with a 3.3 V power supply. The architecture includes a digital signal processor with a first internal bus for transferring instructions and a second internal bus for transferring data. The digital signal processor performs fetching, decoding, reading and execution routines in parallel while simultaneously receiving data.

Abstract: An electronic architecture that provides a portable hard disk drive that can meet the type II PCMCIA specification and which can efficiently operate with a 3.3 V power supply.

Abstract: An electronic architecture that provides a portable hard disk drive that can meet the type II PCMCIA specification and which can efficiently operate with a 3.3 V power supply.

Abstract: An integrated servo circuit that controls the spin motor and voice coil motor of a hard disk drive in response to digital commands that are generated by a microprocessor based controller chip. The servo chip contains a spin motor control circuit and a voice coil control circuit that control the speed of the spin motor and the position of the actuator arm, respectively. The spin motor and voice coil motor control circuits are coupled to a digital to analog converter which converts the digital commands from the controller chip into analog control signals which are utilized to control the spin motor and voice coil motor. Additionally, the servo chip has an analog to digital converter to convert analog signals, such as the servo burst signals, to digital bit strings that relayed to the controller chip. The controller chip and servo chip communicate through a 16 bit synchronous serial port.

Abstract: A method for starting spin-up of a spindle motor in a hard disk drive. When power is initially applied to the spindle motor, the spindle motor is set to a first commutation state. The spindle motor is maintained in this first commutation state for a pre-determined period of time to allow the spindle motor to reach a known null point. Thereupon, the spindle motor is advanced to a second commutation state. The spindle motor is then maintained at this second commutation state for another pre-determined period of time. Finally, the spindle motor is advanced two successive commutation states to a peak torque curve. Once the spindle motor has started spinning, the commutation process is controlled according to the sensed back EMF voltage being generated in the off-phase.