Hitachi Global Storage Technologies Netherlands B.v.

Phong Van Vu

Lee Duyly Nguyentran

Bond-Yen Ting

Farzin Assar

Peter Kuikong Ho

When a HDD is operating at a temperature below a threshold, a partial sine wave is input to the spindle motor to activate the motor to reduce undesirable speed oscillations of the motor. At normal operating temperatures a full sine wave is input for noise reduction.

System and method for establishing spindle motor current during cold temperature operation of HDD

A magnetic recording hard disk drive (HDD) uses adaptive braking of the voice coil motor (VCM) actuator upon unexpected loss of power during a track seek. An adaptive braking controller applies a preselected value of brake voltage to the VCM to reverse the motion of the freely-moving actuator. The value of the selected brake voltage is determined from the actuator velocity. A set of brake voltage values is stored in memory in the HDD, and each brake voltage value corresponds to a band of track seek lengths, with each band representing a range of actuator velocities. For each seek, the value of brake voltage corresponding to the band in which the seek length falls is stored in a register. If emergency power-off (EPO) occurs during the seek, the value of brake voltage is recalled from the register and applied to the VCM to brake the VCM. After the VCM has been adaptively braked in this manner, actuator retract occurs to unload the heads.

Growing community of inventors

San Jose, CA, United States of America

Phong Van Vu