US 2024/0420737 A1 · METHOD OF OPERATING HARD DISK DRIVES, CORRESPONDING CONTROL CIRCUIT, HARD DISK DRIVE AND PROCESSING DEVICE

Abstract

A voice coil motor (VCM) in a hard disk drive is operated in a discontinuous mode with an alternation of on and off times. A drive current to the VCM is facilitated and countered with a variable voltage across the during the on-times and off-times. The intensity of the drive current is controlled as a function of a Back ElectroMotive Force (BEMF) of the VCM. A method includes sampling during the alternation of on-times and off-times first and second values of the voltage across the VCM. The first value is sampled at a first time in response to the end of the off-time. The second value is sampled at a second time in response to the drive current of the VCM zeroing following the supply of drive current to the VCM being countered during the off-time. The BEMF is calculated as a function of first and second values.

Claims20

Dependent claims

A method to operate a voice coil motor (VCM) in a hard disk drive (HDD), the method comprising:

sampling a first value of a voltage across the VCM at a first time corresponding to an end of an OFF time of the HDD alternating between ON and OFF times;
sampling a second value of the voltage across the VCM at a second time corresponding to a drive current of the VCM zeroing following supply of drive current to the VCM being countered during the OFF time, the drive current supplied to the VCM being facilitated and countered, respectively, with a variable voltage across the VCM during the ON and OFF times, an intensity of the drive current controlled as a function of a Back ElectroMotive Force (BEMF) of the VCM;
and
calculating the BEMF of the VCM as a function of first value and the second value.

1 more element

A control circuit configured to operate a voice coil motor (VCM) in a hard disk drive (HDD), the control circuit comprising:

sampling circuitry couplable to the VCM, the sampling circuitry configured to:
sample a first value of a voltage across the VCM at a first time corresponding to an end of an OFF time of the HDD alternating between ON and OFF times,
sample a second value of the voltage across the VCM at a second time corresponding to a drive current of the VCM zeroing following supply of drive current to the VCM being countered during the OFF time, the drive current supplied to the VCM being facilitated and countered, respectively, with a variable voltage across the VCM during the ON and OFF times;
and
processing circuitry configured to:
calculate a Back ElectroMotive Force (BEMF) of the VCM as a function of first value and the second value, and
control an intensity of the drive current applied to the VCM as a function of the calculated BEMF.

4 more elements

A hard disk drive (HDD), comprising:

a voice coil motor (VCM);
and
a control circuit configured to operate the VCM, the control circuit comprising:
sampling circuitry couplable to the VCM, the sampling circuitry configured to:
sample a first value of a voltage across the VCM at a first time corresponding to an end of an OFF time of the HDD alternating between ON and OFF times,
sample a second value of the voltage across the VCM at a second time corresponding to a drive current of the VCM zeroing following supply of drive current to the VCM being countered during the OFF time, the drive current supplied to the VCM being facilitated and countered, respectively, with a variable voltage across the VCM during the ON and OFF times;
and
processing circuitry configured to:
calculate a Back ElectroMotive Force (BEMF) of the VCM as a function of first value and the second value, and
control an intensity of the drive current applied to the VCM as a function of the calculated BEMF.

7 more elements

Dependencies are inferred from the claim text.

Method of operating hard disk drives, corresponding control circuit, hard disk drive and processing device

Life of this patent

Method of operating hard disk drives, corresponding control circuit, hard disk drive and processing device

Life of this patent

Abstract

Claims20