Magnetic disk device and method for measuring counter electromotive voltage of spindle motor
AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
InventorsYu Chen, Kenichiro Ozeki, Koichiro Miyamoto
Life of this patent
Estimating the term…
Abstract
According to an embodiment, a magnetic disk device includes a magnetic disk, a spindle motor that rotates the magnetic disk, a motor driver, and a controller. The motor driver supplies a motor current to the spindle motor and measures a counter electromotive voltage of the spindle motor every time the spindle motor makes one rotation. After the rotation of the magnetic disk starts, the controller adjusts a motor position where the counter electromotive voltage is measured to a set first position.
Claims13
A magnetic disk device comprising:
- a magnetic disk;
- a spindle motor that rotates the magnetic disk;
- a motor driver that supplies a motor current to the spindle motor and starts measuring a counter electromotive voltage of the spindle motor every time the spindle motor makes one rotation at a first position among a plurality of second positions, each of the plurality of second positions being a motor position where a value of the motor current crosses zero;
- and
- a controller that changes, after the magnetic disk starts rotating, a motor position where the counter electromotive voltage is measured every time the spindle motor makes one rotation from the first position to a set third position among the plurality of second positions.
A method for controlling a magnetic disk device, which includes:
- a magnetic disk;
- a spindle motor that rotates the magnetic disk;
- and a motor driver that supplies a motor current to the spindle motor, the method comprising
- starting measuring a counter electromotive voltage of the spindle motor every time the spindle motor makes one rotation at a first position among a plurality of second positions, each of the plurality of second positions being a motor position where a value of the motor current crosses zero;
- and
- changing, after the magnetic disk starts rotating, a motor position where the counter electromotive voltage is measured every time the spindle motor makes one rotation from the first position to a set third position.
Dependencies are inferred from the claim text.