JPH0562396A - Control circuit for magnetic head driving motor - Google Patents

Abstract

PURPOSE:To stop a magnetic head before damaging it by always counting the number of traversed cylinders for magnetic head positioning and immediately stopping the magnetic head at the time of rush of the magnetic head into are area other than a normally used data zone. CONSTITUTION:Contents of a counter 15 which refers to a movement distance signal 18 outputted from a magnetic head 16 and a movement direction signal 19 outputted from a control part 11 to perform counting and those of registers (B) 12 and (L) 13 where movement range values (H) 111 and (L) 112 outputted from the control part 11 are stored respectively are compared with each other by a comparing part 14, and an abnormality signal 110 is outputted to the control part 11 if the counted value is not within the movement range. When receiving the abnormality signal 110, the control part 11 controls a magnetic head driving motor 17 to stop a magnetic head 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device, and more particularly to a control system for a magnetic head drive motor.

[0002]

2. Description of the Related Art Conventionally, in this type of magnetic disk device,
It has a servo disk on which positioning information is recorded to perform magnetic head positioning control, and an outer guard band recording an outer peripheral area outside a data zone where data can be written and read on the servo disk surface,
An inner guard band recording the inner peripheral area inside the data zone is provided.

In the operation of positioning the magnetic head, the magnetic head is moved by passing a unidirectional current through the magnetic head drive motor. The direction of movement of the magnetic head is determined by the direction of the current passed through the magnetic head drive motor. Further, when the magnetic head is positioned at a target position, the number of passing tracks, that is, the number of movements is counted.

[0004]

In the conventional magnetic disk device as described above, when the magnetic head is positioned at a target position, the number of movements is counted and positioned. There are only three types of outer guard band, data zone, and inner guard band on the servo disk surface.

When the magnetic head drive motor is erroneously supplied with a current larger than the specified value or a current in a direction opposite to the direction in which the magnetic head should be supplied at the time of positioning the magnetic head, the magnetic head runs away and the outer guard band or the inner guard is struck. Rush into the band. When the magnetic disk device recognizes that the magnetic head has entered the outer guard band or the inner guard band, it controls the magnetic head drive motor to stop the magnetic head.

However, if the magnetic head drive motor is controlled so as to stop the magnetic head after recognizing the outer guard band or the inner guard band, the speed of the magnetic head becomes too high, and the magnetic head is on the inner guard band or There is a possibility that it cannot stop on the outer guard band and damages the magnetic head.

Therefore, an object of the present invention is to provide a magnetic head drive motor control circuit for stopping the magnetic head without damaging the magnetic head even if the magnetic head runs away.

[0008]

In order to achieve the above object, in a magnetic head drive motor control circuit according to the present invention, a magnetic head drive motor driven for positioning a magnetic head and a moving distance of the magnetic head are provided. A counter that controls the magnetic head drive motor, a register that stores the moving range value of the moving range of the magnetic head from the control unit, and a moving distance signal measured by the counter. It has a comparator for comparing the moving range of the magnetic head and outputting an abnormal signal if it is outside the moving range of the magnetic head.

Further, the counter measures the moving distance of the magnetic head from the input of a moving distance signal indicating the moving amount of the magnetic head on the surface of the storage medium and a moving direction signal indicating the moving direction of the magnetic head. ..

[0010]

In the present invention, by constantly counting the number of movements of the cylinder when positioning the magnetic head, the magnetic head can be immediately stopped when the magnetic head plunges into an area other than the normally used data zone. It was done.

[0011]

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

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a servo disk surface.

In the figure, a magnetic head drive motor control circuit according to the present embodiment includes a control unit 11 and a register (H) 1.
2, a register (L) 13, a comparison unit 14, a counter 15, a magnetic head 16, and a magnetic head drive motor 17
And have.

More specifically, the control 11 is connected to a register (H) 12, a register (L) 13, a comparison section 14, a counter 15 and a magnetic head drive motor 17, respectively.

Register (H) 12 and register (L) 13
Is connected to the comparison unit 14, which compares the counter 15 with the counter 15.
, The counter 15 is connected to the magnetic head 16, and the magnetic head 16 is connected to the magnetic head drive motor 17.

For the signal line, the moving range value (H)
111 is output from the control unit 11 and stored in the register (H) 12, and the moving range value (L) 112 is output from the control unit 11 and stored in the register (L) 13.
9 is output from the control unit 11 to the comparison unit 14 and the counter 15, the abnormality signal 110 is output from the comparison unit 14 to the control unit 11, the movement distance signal 18 is output from the magnetic head 16 to the counter 15, and the magnetic head drive motor Control signal 113
Is output from the control unit 11 to the magnetic head drive motor 17.

Next, the present embodiment configured as described above will be described with reference to FIGS. 1 and 2.

First, of the data zones 23 on the surface of the servo disk 21 shown in FIG. 2, the control section 11 sets the actually used data zone 25 within the movement range and sets the movement range value (H) and the movement range value (L). Register (H) 1
2 and register (L) 13 in advance.

When the magnetic head 16 is positioned, a moving distance signal 18 and a moving direction signal 19 are output to the counter 15 and a moving direction signal 19 is output to the comparing section 14 as the magnetic head 16 moves to a target position. At this time, the moving direction signal 19 determines whether the moving direction of the magnetic head 16 is to the inner circumferential side, that is, to the inner guard band 22 side in FIG.

When the moving direction of the magnetic head is the inner peripheral direction, the counter 15 is counted up by the number of the moving distance signals 18, and the comparing section 14 refers to the moving direction signal 19 to judge the moving direction of the magnetic head 16. The contents of the counter 15 are compared with the register (H) 12.

As a result, when the contents of the counter 15 become larger than the contents of the register (H) 12, that is, the magnetic head 16 is inside the range of the data zone 25 actually used in the data zone 23. When it rushes into, the comparison unit 14 outputs the abnormal signal 110 to the control unit 11.

The control unit 11, which has received the abnormal signal 11,
The magnetic head drive motor control signal 113 is output to the magnetic head drive motor 17 to stop the movement of the magnetic head 16.

On the contrary, when the moving direction of the magnetic head is the outer peripheral direction, that is, the direction toward the outer guard band 24 in FIG.
The counter 15 counts down by the number of moving distance signals 18, and the comparison unit 14 compares the content of the counter 15 with the content of the register (L) 13, and the content of the counter 15 is smaller than the content of the register (L) 13. When it becomes, that is, the data zone 2 actually used by the magnetic head 16
When it has entered the outside of the range of 5, the comparison unit 14 outputs the abnormal signal 110 to the control unit 11.

Then, the control unit 11 which has received the abnormal signal 110 in the same manner as when the moving direction of the magnetic head 16 is in the inner circumferential direction, outputs the magnetic head drive motor control signal 113 to the magnetic head drive motor 17, and The movement of the head 16 is stopped.

[0025]

As described above, according to the present invention, the register for storing the value of the moving range, the counter for inputting the moving distance signal and the signal indicating the moving direction of the magnetic head, and the counter for measuring the moving distance. By comparing the contents with the contents of the register and outputting an abnormal signal to the control unit if it is outside the movement range, the magnetic head positioning is provided by having a control unit for controlling the register and counter and the magnetic head drive motor. When the control of the magnetic head becomes impossible due to an abnormal amount of current flowing in the magnetic head drive motor by mistake, or a reverse current flowing, the data zone actually used by the magnetic head If deviating from the above, the magnetic head can be stopped immediately, and there is an effect of preventing damage to the magnetic head.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a servo disk surface.

[Explanation of symbols]

 11 Control Unit 12 Register (H) 13 Register (L) 14 Comparison Unit 15 Counter 16 Magnetic Head 17 Magnetic Head Drive Motor 18 Moving Distance Signal 19 Moving Direction Signal 21 Servo Disk 22 Inner Guard Band 23 Data Zone 24 Outer Guard Band 25 Actual Used for data zone 110 Abnormal signal 111 Moving range value (H) 112 Moving range value (L) 113 Magnetic head drive motor control signal

Claims (2)

[Claims] 1. A magnetic head drive motor driven to position the magnetic head, a counter for measuring a moving distance of the magnetic head, a control unit for controlling the magnetic head drive motor, and a moving range of the magnetic head. A register that stores a movement range value that is input from the control unit, compares the movement distance signal measured by the counter with the movement range of the magnetic head, and outputs an abnormal signal if it is outside the magnetic head movement range. And a magnetic head drive motor control circuit. 2. The counter measures the moving distance of the magnetic head from the input of a moving distance signal indicating the moving amount of the magnetic head on the storage medium surface and a moving direction signal indicating the moving direction of the magnetic head. The magnetic head drive motor control circuit according to claim 1, wherein: