JPH06187749A - Head positioning circuit for magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of damage due to impact on a magnetic head when abnormality takes place during the seeking operation of the magnetic head by lowering its speeds so as not to collide against a stopper at a high speed. CONSTITUTION:The speed at the time of occurrence of abnormality is detected by an error time speed detecting circuit 1 from a speed signal 7 with an error signal 9 as a trigger, and an address signal 11 corresponding to the speed is outputted. Data for generating a driving current suitable for decelerating the speed at the time of the occurrence of abnormality is stored in advance in a storage circuit 2, and when the address signal and a direction signal 8 indicating the moving direction of the magnetic head are received by the stored circuit, deceleration data 12 indicating a driving current for the direction and deceleration corresponding to the above signals is outputted, and the deceleration data are converted by a D/A converter 3 to output a deceleration signal 13. A switching circuit 4 is set by an error signal, and a driving current 15 based on the driving signal 14 is supplied to a voice coil motor 6 by a current amplifier 5, and hence the magnetic head is decelerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head positioning circuit of a magnetic disk device used for peripheral equipment of a computer.

[0002]

2. Description of the Related Art In a magnetic disk device, when an abnormality occurs while the magnetic head is positioned on a track or when the magnetic head is moving to a target track (hereinafter, seek operation), the magnetic disk device. The go-home operation is performed to move the magnetic head to an area (hereinafter referred to as a home position) in which the magnetic head is retracted when starting and stopping.

Conventionally, in the go-home operation, the current amplifier is instantly made inoperative when an abnormality occurs, and the magnetic head supplying the voice coil motor to the movable magnetic head is positioned or seek operation is performed. When the control current is stopped, the magnetic head is moved to the home position by a force such as an external force applied to the magnetic head itself.

[0004]

In the above-mentioned go-home operation, when an abnormality occurs during seek operation of the magnetic head and the go-home operation is performed, the speed of the magnetic head is instantaneously reduced without slowing down. Since the current amplifier is disabled and the drive current for controlling the seek operation from the current amplifier to the voice coil motor is stopped to try to move the magnetic head to the home position by external force, etc., the magnetic head is almost abnormal. Occurs and the speed at the time of switching to the go-home operation remains the same, and it collides with the stopper on the inner circumference side or the outer circumference side, which causes a strong shock to the magnetic head and increases the risk of damage. there were.

Therefore, the present invention improves on the above-mentioned drawbacks of the prior art, and when an abnormality occurs during the movement of the magnetic head,
The speed of the magnetic head is reduced so that the stopper does not collide with the stopper at a high speed, and damage due to impact does not occur.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to head positioning of a magnetic disk device having an error speed detection circuit, a storage circuit, a D / A converter, a switching circuit, a current amplifier, and a voice coil motor. In the circuit, the speed detection circuit at error receives the speed signal and the error signal as input,
The error signal is used as a trigger to detect the speed from the speed signal and output it as an address signal to the memory circuit. The memory circuit receives the address signal and the direction signal as input, and the deceleration data selected by both signals is D / A converter The D / A converter receives the deceleration data as an input and outputs the result of the D / A conversion as a deceleration signal to the switching circuit. The switching circuit outputs the deceleration signal, the speed control signal and the error. A signal is input, and either the deceleration signal or the speed control signal is selected by the error signal and output as a drive signal to the current amplifier.The current amplifier receives the drive signal and deceleration completion signal as input and During deceleration, the drive signal is output to the voice coil motor as the drive current by the deceleration completion signal, and the deceleration completion signal is output when the deceleration is completed. It is intended to be created, a voice coil motor, the driving current as an input, and employs a configuration for driving the magnetic head, to solve the above problems.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 shows a magnetic head drive circuit including a go-home operation control circuit according to an embodiment of the present invention. Figure 2
Is an example of a waveform representing the operation of the go-home operation control circuit. FIG. 3 is an example of a drive current when the magnetic head is normally made to perform a seek operation.

According to the present invention, when an abnormality occurs during the seek operation of the magnetic head and the magnetic head is moved to the home position by the go-home operation, conventionally, when the abnormality occurs, the speed of the magnetic head is not reduced. The current amplifier is instantly disabled, the supply of drive current for seek operation control from the current amplifier to the voice coil motor is stopped, and the magnetic head is trying to move to the home position due to external force, etc. The speed of the magnetic head at the time of the abnormality is detected from what was colliding with the stopper on the inner circumference side or the outer circumference side at the speed at the time of occurrence of the The speed of the magnetic head is reduced by supplying a deceleration signal suitable for deceleration to the voice coil motor as a drive current. By moving the magnetic head to the home position by force, etc., it is possible to prevent the magnetic head from colliding with the inner or outer stoppers and being damaged at the seek speed at the time of occurrence of abnormality. Has an aim.

Normally, when the seek operation of the magnetic head is performed, the switching circuit 4 is set so that the drive signal 14 output from the switching circuit 4 selects the speed control signal 10 by the error signal 9. Then, the current amplifier 5 outputs the drive signal 14
Is supplied to the voice coil motor 6, and the voice coil motor 6 moves the magnetic head.
The drive current 15 at this time is accelerated as shown in FIG.
The waveform is composed of constant speed and deceleration parts.

Further, when an abnormality occurs during seek operation of the magnetic head and the magnetic head is moved to the home position by the gome home operation, the error-time speed detection circuit 1 is triggered by the error signal 9 indicating the abnormality. 7
Then, the speed at the time of occurrence of an abnormality is detected, and the address signal 11 corresponding to this speed is output. The memory circuit 2 stores in advance data for generating a drive current suitable for decelerating from the speed at which an abnormality has occurred, and stores an address signal 11 and a direction signal 8 indicating the moving direction of the magnetic head. When the storage circuit 2 receives the deceleration data 12 indicating the corresponding direction and the driving current for deceleration.
And the deceleration data 12 outputs the deceleration signal 13 D / A converted by the D / A converter 3. The switching circuit 4 uses the error signal 9 so that the drive signal 14 output from the switching circuit 4 selects the deceleration signal 13.
To set. Then, the current amplifier 5 supplies the drive current 15 based on the drive signal 14 to the voice coil motor 6, decelerates the magnetic head by the voice coil motor 6, and then the memory circuit 2 completes the transmission of the deceleration data 12. The supply of the drive current 15 from the current amplifier 5 to the voice coil motor 6 is stopped by the deceleration completion signal 16 output at the time point, and the magnetic head is moved to the home position by the external force applied to the magnetic head. The drive current 15 during deceleration at this time is as shown in FIG.
The waveform is almost the same as the deceleration portion of the drive current during the normal seek operation, and the waveform changes depending on the speed of the magnetic head when an abnormality occurs.

[0012]

As described above, according to the present invention, when an abnormality occurs during the movement of the magnetic head, a deceleration drive current suitable for decelerating from the speed at that time is generated, and the speed is reduced. Since it is controlled to move to the home position when fully lowered, as in the past, it is controlled to move to the home position instantly without deceleration when an abnormality occurs, and it is fast at the time of abnormality occurrence. There is an effect that the stopper does not collide with the inner peripheral side or the outer peripheral side at a speed and the risk of damage due to impact is eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram of an operation circuit of a magnetic head according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a drive current when a deceleration operation is performed when an abnormality occurs in an operation circuit of a magnetic head according to an embodiment of the present invention.

FIG. 3 is a diagram showing an example of a drive current when the magnetic head normally moves.

[Explanation of symbols]

 1 Speed detection circuit at error 2 Memory circuit 3 D / A converter 4 Switching circuit 5 Current amplifier 6 Voice coil motor 7 Speed signal 8 Direction signal 9 Error signal 10 Speed control signal 11 Address signal 12 Deceleration data 13 Deceleration signal 14 Drive signal 15 Drive current 16 deceleration completion signal

Claims (1)

[Claims] 1. An error speed detection circuit, a memory circuit,
In a head positioning circuit of a magnetic disk device having a D / A converter, a switching circuit, a current amplifier, and a voice coil motor, an error speed detection circuit receives a speed signal and an error signal as inputs and uses the error signal as a trigger. The speed is detected from the speed signal and output as an address signal to the memory circuit. The memory circuit inputs the address signal and the direction signal and outputs deceleration data selected by both signals to the D / A converter. The D / A converter inputs deceleration data and outputs the result of D / A conversion as a deceleration signal to the switching circuit. The switching circuit inputs the deceleration signal, the speed control signal and the error signal, Either the deceleration signal or the speed control signal is selected by the error signal and output as a drive signal to the current amplifier. The amplifier receives the drive signal and the deceleration completion signal, outputs the drive signal to the voice coil motor as the drive current by the deceleration completion signal while decelerating the magnetic head, and becomes inoperative by the deceleration completion signal when the deceleration is completed. A head positioning circuit for a magnetic disk device, wherein a voice coil motor drives a magnetic head by using a drive current as an input.