公开(公告)号：US20240265940A1

公开(公告)日：2024-08-08

申请号：US18417588

申请日：2024-01-19

Applicant: STMicroelectronics International N.V.

Inventor： Michele Boscolo Berto ,  Ezio Galbiati

IPC: G11B5/55 ,  G11B19/20 ,  H02P7/025

CPC classification number: G11B5/5569 ,  G11B19/2009 ,  H02P7/025

Abstract: Embodiments provide a method of operating a voice coil motor via a transconductance loop. The method includes detecting an actual value of a supply voltage of the transconductance loop. An offset compensation signal of the transconductance loop is produced as a function of the detected actual value of the supply voltage based on a relationship between offset values and the supply voltage of the transconductance loop. The offset compensation signal is applied to a loop control signal of the transconductance loop. A drive current is applied to the voice coil motor. The drive current is related to a target drive current that is based on the loop control signal.

公开(公告)号：US20240420737A1

公开(公告)日：2024-12-19

申请号：US18678645

申请日：2024-05-30

Applicant: STMicroelectronics International N.V.

Inventor： Michele Boscolo Berto

IPC: G11B27/36 ,  H02P7/025

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.