Seagate Technology Incorporated

Nan Ling Goh

Kah Liang Gan

Utt Heng Kan

Ban Hok Goh

James Lai Kein Chang

Tze Ming Jimmy Pang

LaiKein James Chang

Yam Pheng Tham

A system for hardware intelligent speed monitoring and auto-retract is disclosed. The system contains a monitoring device that monitors the TACH (Tachometer) output of motor driver. The device provides a trigger to the signal processor and a retract mechanism to retract the actuator when the spindle motor speed is unexpectedly much higher or lower than normal speed. The system DSP (Digital Signal Processor) is unaware of such occurrence.

Intelligent speed monitoring auto retract system

A method for compensating digital samples of an asymmetric read signal is presented. The method involves reading a digital sample of an asymmetric read signal V(t) ( ), generating a compensated sample at least when the digital sample requires compensation ( ), and outputting either the digital sample ( ) or the compensated sample ( ). Also presented is an asymmetry correction block ( ) of a read channel ( ) of a disc drive ( ) that includes an input ( ), a level detector ( ), a compensator ( ), and an output ( ). The level detector ( ) and the compensator ( ) receive the digital sample through the input ( ). The level detector ( ) determines whether the digital sample requires compensation. The compensator ( ) generates a compensated sample at least when the digital sample requires compensation. The output ( ) selectively outputs either the digital sample or the compensated sample.

Method and apparatus for correcting digital asymmetric read signals

A system for low acoustic noise spindle motor commutation is disclosed. The system contains a control device that generates commutation control signals which cause spindle motor drivers to source or sink current through windings of a spindle motor. The windings create electromagnetic fields which induce rotational movement in a spindle motor rotor. Low acoustic noise snubber devices are coupled to each winding and are dynamically configurable by the control device to provide low spindle motor driver charging current upon initial application of power to the spindle motor, and reduced acoustic noise and back EMF-generated current and voltage surges at the spindle motor driver during spindle motor commutation.

System and method for low acoustic noise spindle motor commutation

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Singapore, Singapore

Nan Ling Goh