JP3090165B2 - Power consumption reduction device for magnetic disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reducing power consumption of a magnetic disk drive, and more particularly to an apparatus for reducing power consumption during operations other than write / read operations of a magnetic disk drive. 2. Description of the Related Art In recent years, in response to demands for large capacity and small size of magnetic recording / reproducing devices, magnetic disk devices have been gradually reduced in size. As magnetic disk drives become smaller and more portable, and are powered by batteries,
It is more convenient that the battery can be driven for a long time. Therefore, it is desired to reduce the power consumption of the magnetic disk device and extend the driving time by the battery.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional magnetic disk drive 50 for performing closed loop control by position feedback.
It shows the configuration of FIG. In the figure, 51 is a rotation axis,
52 is a magnetic disk, 53 is a magnetic head, 54 is a swing arm, 55 is a rotating shaft, 56 is a swing motor (generally a voice coil motor:
VCM), 57 denotes a flexible print cable (FPC) for exchanging input / output signals with the magnetic head 53 with the control circuit 59, and 58 denotes a magnetic disk housing.

In the magnetic disk drive 50 configured as described above, data write / read (W /
At the time R), it is necessary to position the magnetic head 53 at the center of the track with an offset of zero. For this purpose, the head positioning control circuit 59 of the magnetic disk device 50 always controls the swing motor 56 to supply an appropriate current so as to maintain the head 53 in the on-track state. That is, as a control method, closed loop control based on position feedback is usually adopted, and the positioning of the head 53 is performed.

[0004]

However, the conventional magnetic disk device 50 has no problem if the external force constantly applied to the swing arm 54 as the positioning actuator of the magnetic head 53 is small. If it is large, the current sufficient to cancel the external force is supplied to the swing motor 5.
5, the power consumption of the entire apparatus increases.

The external force is caused by the magnetic head 53
The reaction force of the flexible printed cable (FPC) 57 for sending a signal from the FPC to the write / read / write circuit is conceivable. This flexible printed cable 5
As shown in FIG. 5, 7 is bent between one side surface of the swing arm 54 and the housing 58 of the magnetic disk device 50 so as to follow the movement of the swing arm 54 indicated by the arrow A. In this state, the reaction force B for returning the bending of the flexible print cable 57 is applied to the side surface of the swing arm 54.

The magnitude of the reaction force B is not a problem when the swing arm 54 is large because it is smaller than the driving force when the swing arm 54 is large. However, when the driving force of the actuator is small in a small magnetic disk device or the like. Has a size that cannot be ignored.
That is, the flexible printed cable 57
Therefore, the control power of the head offset caused by the reaction force B occupies a large part of the power consumption of the entire apparatus.

Therefore, according to the present invention, during the tracking control of the magnetic disk drive, the current to be passed to the oscillating motor for reducing the position offset to zero is suppressed except during the write / read operation of the head. It is an object of the present invention to provide a magnetic disk drive capable of reducing the power consumed by a dynamic motor.

[0008]

FIG. 1 is a block diagram showing a configuration of a power consumption reducing apparatus of a magnetic disk drive according to the present invention which achieves the above object.
Is shown in As shown in the figure, the power consumption reduction device for a magnetic disk drive according to the first embodiment of the present invention includes at least one magnetic disk D, a head H for reading and writing information from and to this magnetic disk D, A read / write operation determining means 1 for determining whether or not there is a write / read command at the time of tracking control of the magnetic disk device in a magnetic disk device including a rocking motor M for moving the head H on the magnetic disk D; An offset compensating current value judging means 2 for judging whether or not an offset compensating current value for setting the head position offset to zero when there is no write / read command is not less than a certain value; Target position changing means 3 for changing the target position of the head to a direction in which the offset compensation current approaches zero when the value is equal to or more than the value. It is characterized in Rukoto.

Further, according to a second embodiment of the present invention, there is provided a power consumption reducing device for a magnetic disk device, wherein the target position changing means 3 of the power consumption reducing device for a magnetic disk device according to the first embodiment is replaced with an offset compensation current value. When a certain value or more, in the head positioning feedback loop circuit system,
Integral control element exclusion means 4 for removing the integral control element from the loop
It is characterized by having provided.

[0010]

According to the power consumption reducing device for a magnetic disk drive of the first embodiment of the present invention, the read / write operation judging means 1 performs the tracking control of the magnetic disk drive.
It is determined whether or not there is a write / read command. When there is no write / read command, the offset compensation current value determining means 2 determines whether or not an offset compensation current value for setting the head position offset to zero is equal to or more than a certain value. Is determined. Then, when the offset compensation current value is equal to or more than a certain value, the target position changing means 3 changes the target position of the head in a direction in which the offset compensation current approaches zero.

Further, according to the power consumption reducing device for a magnetic disk drive of the second embodiment of the present invention, instead of the target position changing means 3 of the power consumption reducing device for the magnetic disk drive of the first embodiment, integral control is performed. When the offset compensation current value is equal to or more than a certain value, the element control means removes the integral control element from the loop in the head positioning feedback loop circuit system.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 2 shows the configuration of an embodiment of a power consumption reducing device for a magnetic disk drive according to the present invention. In the figure, reference numeral 70 denotes a magnetic disk unit, and a spindle 71 on which a plurality of magnetic disks 72 as information storage media are mounted is rotated by a spindle motor 75, and a magnetic head 73 is attached to a rotating shaft 76 of a swing motor 74. Attached to the tip of the protruding arm, the coil 77
The magnetic disk 72 is moved (seeked) in the radial direction of the magnetic disk 72 by the and the magnet 78, and these are housed in a housing 79. The magnetic disk unit 70
Are the speed control unit 20, the positioning control unit 30, the control unit 4
0, a changeover switch 50, and a power amplifier 60.

The speed control unit 20 generates a speed error signal ΔV based on the position signal PS based on the servo signal from the magnetic head 73, and the positioning control unit 30 converts the position signal PS into PI-
D (proportional, integral, differential) processed signal and detection signal i
From the signal that has been low-pass filtered to the positioning signal ΔP
Occurs. When an external movement instruction is given, the control unit 40 calculates the amount of movement to the target position, controls the speed control unit 20 to generate a speed error signal ΔV, and controls the speed of the swing motor 74. At the same time, a coarse / fine switching signal MS is issued in the vicinity of the target position, and a changeover switch 50 described later is operated. And the changeover switch 5
0 is switched in response to the coarse / fine switching signal MS.
In the fine instruction, the positioning signal ΔP is given to the swing motor 74. Further, the power amplifier 60 power-amplifies the output of the changeover switch 50 and supplies it to the swing motor 74 to drive it.

As described above, the head is positioned by reading the position information written on the disk 72 with the head 73 and feeding it back. The loop gain of the control system is generally increased in order to reduce the position error with respect to various disturbances. FIG. 3 shows the internal configuration of the positioning control circuit 30 of FIG. The positioning control circuit 30 has a target position PM and a position signal P
S, that is, a deviation from the track center is given, and after the position signal PS is subtracted from the target position PM, the integration element 3
1, PI element 32 and differential element 33
D control is performed to generate a positioning signal ΔP.

In the magnetic disk drive configured as described above, according to the present invention, the swing motor 7 for making the position offset of the magnetic head 73 from the target track zero is provided.
The steady-state current to be passed through 4 is kept small except when the magnetic head 73 writes / reads data on / from the magnetic disk 73. That is, the position offset of the magnetic head 73 from the target track is allowed except when the magnetic head 73 writes / reads data to / from the magnetic disk 73.

As a procedure for suppressing the steady current as described above, the following two methods can be considered in the position feedback circuit system. (1) Change the target position so that the offset compensation current approaches zero. Generally, a swing arm 74 which is an actuator of the head
When the driving force is zero, the motor tries to move to a position where the external force is balanced. Therefore, if the target position of the position control system is changed in that direction, the steady-state current value required for offset compensation decreases. (2) Remove the integral control element.

Generally, in a feedback control system, an integral element is added to the system in order to eliminate a steady-state error. That is, the output of this integration element is equal to the steady offset compensation current. Therefore, if the output of the integral element is omitted from the feedback control system, an offset occurs in the control target (head), but the output current value decreases. First
The procedure of (1) will be described. The head positioning control circuit is often constituted by a digital control system using a microcomputer or the like. FIG. 4 (a) shows a flowchart of an embodiment of the present invention in a digital control system. FIG.
The routine of (a) is executed every predetermined time.

In step 401, an observation value is input.
In the following step 402, it is determined whether the magnetic head is in the read / write mode. And step 40
Step 2 if read / write mode in (YES)
Proceeding to 405, the process proceeds to step 406 with the target position of the magnetic head as the track center. On the other hand, if it is not the read / write mode in step 402 (NO), the process proceeds to step 403, where it is determined whether or not the offset compensation current is equal to or smaller than a constant value K. If the offset compensation current is equal to or smaller than the constant value K, the process proceeds to step 405, and the process proceeds to step 406 with the target position of the magnetic head as the track center. However, if the offset compensation current exceeds the fixed value K, the process proceeds to step 404, so that the target position of the magnetic head does not have to be at the track center, that is, the target position is set so that the offset compensation current approaches zero. An offset is added to the position itself.

When the processing of step 404 or step 405 is completed, in step 406, the control amount calculation processing (P
ID calculation processing) is performed.
That is, the current drive value ΔP of the oscillating motor is output, and this routine ends in step 408. With the above control, the power consumption of the swing motor 74 can be reduced. That is, since the time other than the data write / read time is longer than the data write / read time as a whole, suppressing the steady current value at this time has a great effect.

According to the apparatus for reducing power consumption of a magnetic disk drive of the present invention, when a data write / read command is issued from a host controller, it is necessary to return to an original steady current value in order to eliminate an offset. This causes a delay in access time. This is a case where the target track for data writing / reading is the same track where the head is currently located, and if the target track is another track, a seek operation for moving the head to that track. , The offset compensation operation is included in the seek operation and cannot be a factor of access delay.

Next, the procedure (2) will be described. this
In the procedure (2), the step 404 in the procedure (1) shown in FIG. 4 (a) can be simply changed to the step 404 'shown in FIG. 4 (b). In this step 404 ', instead of adding an offset to the target position, the output of the integration element 31 is controlled during the control calculation processing by, for example, the switch shown in FIG.
The same effect can be obtained by turning off the switch 34 and removing it.

[0022]

As described above, according to the present invention,
In particular, in a small magnetic disk drive, the power consumed by the voice coil motor can be reduced, so that the cost and reliability of the drive can be improved.

[Brief description of the drawings]

FIG. 1 is a principle configuration diagram showing a configuration of a power consumption reduction device of a magnetic disk drive of the present invention.

FIG. 2 is a block circuit diagram showing a configuration of an embodiment of a power consumption reducing device for a magnetic disk drive according to the present invention.

FIG. 3 is a block diagram illustrating a configuration of a positioning control unit in FIG. 2;

4 (a) is a flowchart showing a control procedure according to one embodiment of the present invention, and FIG. 4 (b) is a flowchart showing a control procedure according to another embodiment of the present invention, showing a modification of FIG. 4 (a). It is.

FIG. 5 is a plan view showing a configuration of a conventional magnetic disk drive.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Read / write operation determination means 2 ... Offset compensation current value determination means 3 ... Target position change means 4 ... Integral element control element elimination means 30 ... Positioning control unit 31 ... Integral element 32 ... Proportional element 33 ... Differential element 70 ... Magnetic disk unit 72 magnetic disk 73 magnetic head 74 oscillating motor 76 rotating shaft 77 coil 78 magnet 79

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-114260 (JP, A) JP-A-4-85769 (JP, A) JP-A-4-34778 (JP, A) JP-A-1- 229475 (JP, A) JP-A-63-211176 (JP, A) JP-A-63-9908 (JP, A) JP-A-3-209679 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) G11B 21/10 G11B 19/10

Claims (2)

(57) [Claims] At least one magnetic disk (D)
A head (H) for reading and writing information from and to the magnetic disk (D); and a swing motor (M) for moving the head (H) on the magnetic disk (D). A read / write operation determining means (1) for determining whether or not there is a write / read command during tracking control of a magnetic disk drive; and a head position offset when there is no write / read command. Compensation current value determination means (2) for determining whether or not an offset compensation current value for setting the offset value to be equal to or more than a certain value, and offsetting the target position of the head when the offset compensation current value is more than a certain value. And a target position changing means (3) for changing the compensation current in a direction approaching zero. . 2. At least one magnetic disk (D)
A head (H) for reading and writing information from and to the magnetic disk (D); and a swing motor (M) for moving the head (H) on the magnetic disk (D). A read / write operation determining means (1) for determining whether or not there is a write / read command during tracking control of a magnetic disk drive; and a head position offset when there is no write / read command. Compensation current value judging means (2) for judging whether or not the offset compensation current value for setting the value of the offset compensation current to be equal to or more than a certain value; Means for removing integral control elements from the loop in the system (4)
And a power consumption reduction device for a magnetic disk drive.