Seagate Technology Incorporated

Rigidyne Corporation

Seagate LLC

LeRoy A Volz

Daniel R Vigil

Khosrow Mohajerani

Lisa Fredrickson

Joseph M Sampietro

Anoush M Fard

Jeffrey G Barina

Muhammad A Hawwa

Haim Nissimov

Tien Q Le

Dennis C Stone

Raymond E Hurst

Stephen R Manz

A system for positioning a transducing head in a disc drive device over a selected track of a rotatable disc includes an actuator arm which is rotatable about an axis, a head suspension mechanism connected to the actuator arm, and a slider carrying a transducing head and supported by the head suspension mechanism. A low resolution motor moves the actuator arm about the axis to effect coarse movement of the head between tracks of the disc. A piezoelectric element is embedded in the actuator arm to distort the arm to effect fine positioning of the head. Control circuitry distributes electrical signals to the low resolution motor and the piezoelectric element to selectively control movement thereof. The piezoelectric element is embedded in the actuator arm by removing a predetermined amount of material from the actuator arm and bonding the piezoelectric element in the resulting space in the actuator arm.

Method of making an actuator arm integrated piezoelectric microactuator

In a peak detection system having a variable gain amplifier (VGA), a counter is initialized and a countdown is triggered. Each time a qualified peak is detected, the counter is re-initialized. If the countdown is completed, the VGA gain is updated. This method can be used to boost amplifier gain that is too low to generate a qualifying threshold, even while overlooking short periods of very low output.

Amplifier gain control method using conditional updating

A digital peak detection system digitizes analog signals and provides absolute values to a series of one cycle delays, and to a sequence of comparator stages. Each digital sample is parallel compared to a number of preceding samples equal to the number of active comparator stages. Control signals activate comparator stages to determine sample comparison window length, including lengths exceeding the number of samples between recorded peaks. Peak detection is optimized using a variable gain amplifier whose gain is updated based upon amplitude difference between actual and desired peak samples. When sample amplitudes are smaller than a qualifier threshold, a countdown timer increases amplifier gain after lapse of a programmed time without detecting a qualified pulse. Gain is also updated when the analog to digital converter saturates. Initial gain values can be programmed, and gain stored at the end of a servo mode for future use in reducing gain control loop convergence time.

Method and apparatus for a digital peak detection system including a

Actuator arm integrated piezoelectric microactuator

A method and apparatus determining head position of a data transducer head relative to a selected one track of a multiplicity of concentric tracks within a magnetic/disc drive is provided. At least one prerecorded servo sector within a data track includes four time staggered servo bursts. The first pair and second pair of servo bursts are radially offset from each other by generally a burst width such that an edge from each of the pair are substantially co-linear in forming a track null. The first pair is radially offset from the second pair by one-half of the burst width. The first pair is read to determine a first relative amplitude therebetween, and the second pair is read to determine a second relative amplitude therebetween. Additionally, the radially offset and time staggered servo bursts prerecorded on the servo sector can be of varying width and numbered to create the plurality of track nulls within a data track about which the head can be positioned.

Disc drive system using multiple pairs of embedded servo bursts

Junction overheating in an actuator controller IC used to position read/write heads in a magnetic disc storage device is prevented by temporarily decreasing actuator controller IC output signal duty cycle when excessive junction temperature is present. The present invention includes means for monitoring and comparing actuator controller IC junction temperature to a reference temperature, and for outputting a warning signal when junction temperature exceeds the reference temperature by too large a margin. The present invention introduces a time delay into the output signal from the actuator controller IC when the warning signal is present. The time delay may be fixed or variable in duration, and may be varied progressively in duration. The time delay may be generated using circuitry, software, firmware, or a combination thereof.

Junction temperature status sensing and reduction for integrated power

A thermal offset compensation system is provided for use in a computer disk drive unit have a dedicated servo surface on one of a plurality of memory storage disks. The disk drive unit has a plurality of electromagnetic heads displaced as a group relative to respective storage surfaces on the disks to read and/or write data in concentric tracks. One of the heads comprises a servo head for reading servo data prerecorded onto the dedicated servo surface to align the remaining heads relative to corresponding cylinders of data tracks. Thermally induced offsets of the data heads relative to the servo head are measured on one or more calibration cylinders located in the inner and outer guard bands of each storage surface. The average offset of the data heads, taken collectively, is determined and subsequently compensated-for when any data head is utilized to read or write data on a selected track. The thermal compensation offset is determined during a spin-up operation of the disk drive unit, and then periodically thereafter upon receipt of any host command by the disk drive unit.

Thermal offset compensation for high density disk drives

An adaptive velocity profile system is provided for variably controlling a disk drive head in a computer disk drive or the like, to obtain substantially minimum seek times in accordance with variable operating conditions. The system monitors actual performance of the head in the course of a seek step during which the head is displaced relative to a memory storage disk for alignment with a selected track on the disk, and wherein the head performance is variable in response to a range of parameters such as temperature, power supply voltage, mechanical stiffness, etc. The monitored head performance as represented, for example, by head acceleration at the initiation of a seek step and/or by a track address mismatch at the conclusion of a seek step is used, in the preferred form, to select an appropriate one of several available velocity profiles for controlled head deceleration at the conclusion of a subsequent seek step. The selected velocity profile is chosen for obtaining the fastest possible seek times consistent with current operating conditions.

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Northridge, CA, United States of America

LeRoy A Volz