Voltage mode using pseudo current limit
View Patent ↗According to an aspect of the invention, a method includes: applying a voltage across a motor to accelerate the motor over a predetermined number of time intervals; determining whether a current flowing through the motor decreases as the motor accelerates over the predetermined number of time intervals; and increasing the voltage by a predetermined voltage amount during each time interval if it is determined that the current is decreasing.
1. A method comprising:
applying a voltage across a motor to accelerate the motor over a predetermined number of time intervals;
determining whether a current flowing through the motor decreases as the motor accelerates over the predetermined number of time intervals; and
increasing the voltage by a predetermined voltage amount during each time interval if it is determined that the current is decreasing.
2. The method of claim 1 , where increasing the voltage by a predetermined voltage amount includes increasing the voltage by a predetermined amount corresponding to a difference between the current and a current limit.
3. The method of claim 1 , where increasing the voltage by a predetermined voltage amount includes increasing the voltage in small incremental steps.
4. The method of claim 1 , where increasing the voltage by a predetermined voltage amount includes increasing the voltage by a predetermined amount until a predetermined speed of the motor has been reached.
5. The method of claim 4 , further comprising:
maintaining the motor at the predetermined speed;
determining a current associated with maintaining the motor at the predetermined speed;
monitoring the voltage supplied to the motor for voltage fluctuation; and
adjusting the current associated with maintaining the motor at the predetermined speed to compensate for the voltage fluctuation.
6. A disk drive comprising:
a voice coil motor that actuates a head over a disk;
a motor that rotates the disk, the motor including a plurality of windings;
a driver that applies a voltage to the windings of the motor; and
a controller that interacts with the driver to
apply the voltage across the motor to accelerate the motor over a predetermined number of time intervals,
determine whether a current flowing through the motor decreases as the motor accelerates over the predetermined number of time intervals, and
increase the voltage by a predetermined voltage amount during each time interval if it is determined that the current is decreasing.
7. The disk drive of claim 6 , where the controller increases the voltage by a predetermined amount corresponding to a difference between the current and a current limit.
8. The disk drive of claim 6 , where the controller increases the voltage in small incremental steps.
9. The disk drive of claim 6 , where the controller increases the voltage by a predetermined amount until a predetermined speed of the motor has been reached.
10. The disk drive of claim 9 , where the controller:
maintains the motor at the predetermined speed;
determines a current associated with maintaining the motor at the predetermined speed;
monitors the voltage supplied to the motor for voltage fluctuation; and
adjusts the current associated with maintaining the motor at the predetermined speed to compensate for the voltage fluctuation.
11. A device for controlling a disk drive comprising:
circuitry configured to apply a voltage across a motor of the disk drive to accelerate the motor over a predetermined number of time intervals;
circuitry configured to determine whether a current flowing through the motor decreases as the motor accelerates over the predetermined number of time intervals; and
circuitry configured to increase the voltage by a predetermined voltage amount during each time interval if it is determined that the current is decreasing.
12. The device of claim 11 , where the circuitry configured to increase the voltage increases the voltage by a predetermined amount corresponding to a difference between the current and a current limit.
13. The device of claim 11 , where the circuitry configured to increase the voltage increases the voltage in small incremental steps.
14. The device of claim 11 , where the circuitry configured to increase the voltage increases the voltage by a predetermined amount until a predetermined speed of the motor has been reached.
15. The device of claim 14 , further comprising:
circuitry configured to maintain the motor at the predetermined speed;
circuitry configured to determine a current associated with maintaining the motor at the predetermined speed;
circuitry configured to monitor the voltage supplied to the motor for voltage fluctuation; and
circuitry configured to adjust the current associated with maintaining the motor at the predetermined speed to compensate for the voltage fluctuation.