Automatic head retract system for disk drive
AssigneePeripheral Technology, Inc.
InventorsDonald G. Stupeck, Gaston A. Palombo, Ara W. Nazarian, Hugh K. Gagnier
Life of this patent
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Abstract
An automatic head retract system for a disk drive is disclosed which operates in response to electric power turn off to retract the heads to a landing zone on the disk surface. The heads are retracted by operating a positioner motor under the control of logic internal to the disk drive unit without intervention by a host computer. The positioner motor comprises a multiphase DC brushless motor which, after power loss, is supplied with current from a capacitor charged during normal drive usage and by the back EMF of a spindle motor. A latch mechanically locks the heads in the landing zone.
Claims15
A disk drive unit including:
- a spindle mounted for rotation;
- one or more disks supported on said spindle, each disk including at least one data surface having a data zone and a landing zone;
- a head supported adjacent to each data surface;
- positioner means for selectively positioning said head on said data surface;
- a spindle motor coupled to said spindle, said spindle motor including at least first and second drive windings;
- a positioner motor coupled to said positioner means, said positioner motor including at least first and second drive windings;
- a source of DC voltage;
- spindle motor switch means connecting said voltage source to said spindle motor drive windings;
- spindle motor commutation means connected to said spindle motor switch means for energizing said spindle motor drive windings in a predetermined sequence to rotate said spindle;
- positioner motor switch means connecting said voltage source to said positioner motor drive windings;
- positioner motor commutation means connected to said positioner motor switch means for energizing said positioner motor drive windings in accordance with a first predetermined sequence to move said head inwardly toward said spindle or a second predetermined sequence to move said head outwardly away from said spindle;
- capacitor means connected to said voltage source substantially in parallel with said positioner motor switch means for being charged by said voltage source during normal operation of said disk drive unit;
- means for detecting a voltage fault condition;
- means responsive to said voltage fault condition for disabling said spindle motor switch means to allow said spindle motor windings to produce a back EMF for charging at least a portion of said capacitor means;
- and
- means responsive to said voltage fault condition for causing said positioner motor commutation means to energize said positioner motor drive windings to move said head to said landing zone.
Dependencies are inferred from the claim text.