Method of operating hard disk drives, corresponding control circuit, hard disk drive and processing device
AssigneeSTMicroelectronics S.r.l.
InventorEzio Galbiati
Life of this patent
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Abstract
A back electromotive force (BEMF) of a spindle motor in a hard disk drive is rectified and exploited to drive a voice coil motor (VCM) in the hard disk drive to retract the heads of the hard disk drive to a park position. The VCM is driven in a discontinuous mode comprising an alternation of VCM on-times and VCM off-times. Rectifying the BEMF of the spindle motor is discontinued before the end of the VCM off-times, Toff with the spindle motor brought into a brake condition wherein the spindle motor is short-circuited and the spindle BEMF forces currents through the windings of the spindle motor. The spindle current is thus pre-charged and made ready to cope with a VCM current request at the next VCM on-time.
Claims20
A method, comprising:
- rectifying a back electromotive force (BEMF) of a spindle motor in a hard disk drive;
- driving, in a discontinuous mode, at least one voice coil motor (VCM) in the hard disk drive with the BEMF of the spindle motor to retract heads of the hard disk drive to a park position, the discontinuous mode comprising an alternation of VCM on-times and VCM off-times;
- discontinuing rectifying of the BEMF of the spindle motor during the VCM off-times;
- and
- bringing the spindle motor into a brake condition, during which the spindle motor is short-circuited and the BEMF of the spindle motor forces currents through windings of the spindle motor.
A control circuit in a hard disk drive having a spindle motor, wherein the control circuit is configured to:
- rectify a back electromotive force (BEMF) of the spindle motor in the hard disk drive;
- drive, in a discontinuous mode, at least one voice control motor (VCM) in the hard disk drive with the BEMF of the spindle motor to retract heads of the hard disk drive to a park position, the discontinuous mode comprising an alternation of VCM on-times and VCM off-times;
- discontinue rectifying the BEMF of the spindle motor during the VCM off-times;
- and
- bring the spindle motor into a brake condition, wherein the spindle motor is short-circuited and the BEMF of the spindle motor forces currents through windings of the spindle motor.
A hard disk drive, comprising:
- a spindle motor;
- at least one voice coil motor (VCM);
- and
- a control circuit coupled to the spindle motor and the at least one VCM, and configured to:
- rectify a back electromotive force (BEMF) of the spindle motor;
- drive, in a discontinuous mode, the at least one VCM with the BEMF of the spindle motor via a VCM power stage to retract heads of the hard disk drive to a park position, the discontinuous mode comprising an alternation of VCM on-times and VCM off-times;
- discontinue rectifying the BEMF of the spindle motor during the VCM off-times;
- and
- bring the spindle motor into a brake condition, wherein the spindle motor is short-circuited and the BEMF of the spindle motor forces currents through windings of the spindle motor.
Dependencies are inferred from the claim text.