JPH06111501A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent erroneous detection of a track 00 due to damping by including a brake pulse in a drive signal for seek operation. CONSTITUTION:A step signal S and a direction signal D are inputted to an intermediate value pulse/phase pulse generating circuit 30, and the step signal as an intermediate value pulse signal and phase A and C signals are generated. A signal 32 including these A and C signals is inputted to a brake pulse generating circuit 40, where the brake pulse is generated. This brake pulse as a short inverted pulse and the signal 32 are added up by an adding circuit 41 to become the drive signal 42, and the signal 42 is supplied via a driver 44 to a step motor 46.

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 improvement of a drive system of a stepper motor in the magnetic disk device.

[0002]

2. Description of the Related Art In the conventional stepper motor drive system, an external step pulse signal is first fetched from a system into a signal processing device in a magnetic disk device such as a floppy disk device. In this signal processing device, an intermediate value close to approximately the middle between consecutive step pulse signals from the outside is calculated. A stepper motor drive pulse (excitation phase switching pulse) is generated from this intermediate value signal and an external step pulse signal. Further, the stepper motor drive pulse output from the signal processing device is input to a drive device that drives the stepper motor, and the stepper motor is driven by the output from this drive device.

[0003]

However, when a stepper motor using a magnet having a relatively weak torque is used, the stepper motor also lowers the coil resistance and the drive current to reduce the actual torque balance of the stepper motor. Then, the average torque is adjusted.However, when such a stepper motor is used, overrun occurs from the fixed position every time the excitation phase is switched or when the stepper motor is stopped, and it is difficult to determine the constant value. It is not fixed to the position, and this becomes a damping amount and appears as a reproduction output or seek noise from the magnetic head. Further, if the overrun is too large, when the seek operation is performed from the inner circumference to the outer circumference, the track 02 position and the track 0 position are
Tamping while moving to the 1 position or the track 00 position may cause an erroneous detection in which the track 00 signal is output at the position of the same excitation phase as the track 00 signal output condition but not at the track 00 position. is there.

The above-mentioned drawbacks of the conventional technique will be described in more detail with reference to the drawings. FIG. 6 is a waveform diagram showing a conventional stepper motor drive pulse. As shown in FIG. 6, the stepper motor drive pulse is composed of, for example, phase A and phase C, and these phase signals are first generated from an external step signal a and a step signal b which is an intermediate value pulse signal. , Step signals a and b and a direction signal (not shown). FIG. 7 is a waveform diagram showing a reproduction output and a state of damping when a seek is performed from the vicinity of track 06 when data is written only to track 00 to track 00 using phase signals A and C. As is clear from FIG. 7, there is a relatively large damping amount.

FIG. 8 is a side view of the main part of the magnetic disk device, and FIG. 9 is an enlarged side view showing the movement of the shield plate mounted on the carriage with respect to the track 00 sensor.
In FIG. 8, the carriage on which the magnetic head 12 and the shield plate 16 are mounted is guided along the lead screw 14 rotated by the stepper motor 20. Shield 16
Is arranged so that, when the magnetic head 12 mounted on the carriage 10 reaches the track 00 position of a recording medium such as a floppy disk, the track 00 sensor is operated to output a track 00 position signal indicating the track 00 position. Has been done. The track 00 sensor includes, for example, a light emitting element 18a and a light receiving element 18b (FIG. 9).
reference). As shown in FIG. 9, when the amount of damping is large, the shielding plate 16 may overrun greatly even if it should stop at the track 02, causing the track 00 sensor to operate.

FIG. 10 shows a step signal, track 00 sensor output, and track 00 in the case shown in FIG.
It is a figure which shows each waveform of a signal. As is clear from FIG. 10, when the track 00 sensor is in the same phase as the track 00 output at the track 02 position (the hatched portion of the step signal in FIG. 10), the track 00 sensor still reaches the track 00 position after the carriage is stabilized. However, the track 00 signal is output due to a malfunction.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic disk device in which a damping amount is reduced to prevent malfunction.

[0008]

In order to achieve the above-mentioned object, the present invention is a magnetic disk apparatus which seeks a recording head on a magnetic disk to perform recording and reproduction, and drives a stepper motor for seeking. Phase pulse generating means for generating a phase pulse for operating, a brake pulse generating means for generating a brake pulse by receiving a phase pulse or a step signal from the phase pulse generating means, and a phase pulse from the phase pulse generating means And a adding means for receiving a brake pulse from the brake pulse generating means and adding these pulses to generate a drive signal for driving the stepper motor. .

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described with reference to the drawings. First, a first embodiment will be described with reference to FIGS. 1 is a circuit block diagram of a first embodiment of the present invention, FIG. 2 is a detailed circuit block diagram of an intermediate value pulse / phase pulse generation circuit in the circuit block diagram of FIG. 1, and FIG. , Step signal, phase A signal,
FIG. 4 is a waveform diagram of a phase C signal, and FIG. 4 is a reproduction output waveform diagram of the magnetic head. As shown in FIG. 1, the first aspect of the present invention
The circuit block of the embodiment includes an intermediate value pulse / phase pulse generation circuit 30, a brake pulse generation circuit 40, an addition circuit 41, and a driver 44. A step signal and a direction signal are supplied from the system side to a magnetic disk device side such as a floppy disk drive (FDD). The step signal and the direction signal are input to the intermediate value pulse / phase pulse generation circuit 30, and the intermediate value pulse / phase pulse generation circuit 30 generates a step signal which is an intermediate value pulse signal, a phase A signal, and a phase C signal. It More specifically, in this embodiment, the intermediate value pulse / phase pulse generating circuit 30 receives a step signal (specifically, a step a signal) (see FIG. 3) as shown in FIG. Intermediate value pulse signal (specifically, step b signal)
An intermediate value pulse generation circuit 34 for generating (see FIG. 3),
An adder circuit 35 for adding the step a signal and the generated step b signal, and a phase pulse for receiving the output from the adder circuit 35 and the direction signal from the system to generate a phase A signal and a phase C signal (see FIG. 3) And a generating circuit 36.

Intermediate value pulse / phase pulse generation circuit 3
The signal 32 including the phase A signal and the phase C signal generated at 0 is input to the brake pulse generation circuit 40, and the brake pulse generation circuit 40 generates a brake pulse. The brake pulse is a short inversion pulse (indicated by a dotted line in FIG. 3) generated immediately after the switching of each phase of the signal 32 (phase A signal, phase C signal) (for example, for 500 μs). . The brake pulse, which is a short inverted pulse, and the signal 32 are added by the adder circuit 41 to form the drive signal 42, which is passed through the driver 44 to the stepper motor 4
6 is supplied. As described above, since the drive signal 42 includes the brake pulse, the braking operation is performed after the phase switching. FIG. 4 shows a reproduction output waveform from the magnetic head when a seek operation is performed using a drive signal including such a brake pulse.

FIG. 5 shows a circuit block diagram of a second embodiment of the present invention. In this embodiment, the brake pulse generating circuit receives the output signal 37 of the adding circuit 35 in the intermediate value pulse / phase pulse generating circuit 30, and the drive signal 42 is the phase pulse generating circuit 3.
The output of No. 6 and the output of the brake pulse generating circuit 40 are added by the adder circuit 41.

[0012]

As described above, according to the present invention, by including the brake pulse in the drive signal for seeking, it is possible to prevent erroneous detection of the track 00 due to damping.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a first embodiment of the present invention.

FIG. 2 is a detailed circuit block diagram of an intermediate value pulse / phase pulse generation circuit in the circuit block diagram of FIG. 1.

FIG. 3 is a waveform diagram of a step signal, a phase A signal, and a phase C signal.

FIG. 4 is a reproduction output waveform diagram of the magnetic head.

FIG. 5 is a circuit block diagram of a second embodiment of the present invention.

FIG. 6 is a waveform diagram showing a conventional stepper motor drive pulse.

FIG. 7 is a waveform diagram showing reproduction output and damping when seek is performed from near track 06 to track 00 when data is written only on track 00 using phase signals A and C. is there.

FIG. 8 is a side view of a main part of the magnetic disk device.

FIG. 9 is an enlarged side view showing the movement operation of the shield plate mounted on the carriage with respect to the track 00 sensor.

10 is a diagram showing respective waveforms of a step signal, a track 00 sensor output, and a track 00 signal in the case as shown in FIG.

[Explanation of symbols]

 10 Carriage 12 Magnetic Head 14 Lead Screw 16 Shielding Plate 18 Track 00 Sensor 20 Stepper Motor 30 Intermediate Value Pulse / Phase Pulse Generation Circuit 34 Intermediate Value Pulse Generation Circuit 36 Phase Pulse Generation Circuit 40 Brake Pulse Generation Circuit

Claims (5)

[Claims] 1. In a magnetic disk device for performing recording and reproduction by seeking a recording head on a magnetic disk, phase pulse generating means for generating a phase pulse for driving a stepper motor for seeking, and the phase puller. Brake pulse generating means for generating a brake pulse by inputting a phase pulse or step signal from the generating means, and those pulses for receiving a phase pulse from the phase pulse generating means and a brake pulse from the brake pulse generating means And an adding means for generating a drive signal for driving the stepper motor. 2. The magnetic disk drive according to claim 1, wherein the phase pulse generating means receives an intermediate step pulse signal from a system and generates an intermediate pulse signal at an intermediate position of the intermediate step pulse signal. An adder circuit for adding the step signal and the intermediate value pulse signal, and a phase pulse generator circuit for receiving the added signal output from the adder circuit and the direction signal from the system to generate a phase pulse signal. A magnetic disk device comprising: 3. The magnetic disk device according to claim 2, wherein the brake pulse generating means receives a phase pulse from a phase pulse generating circuit of the phase pulse generating means and generates a brake pulse. And a magnetic disk device. 4. The magnetic disk device according to claim 2, wherein the brake pulse generating means generates a brake pulse by receiving the added signal from the adding circuit of the phase pulse generating means. And a magnetic disk device. 5. The magnetic disk drive according to claim 1, wherein the brake pulse is an inversion pulse that is generated almost immediately after the switching of each phase of the phase pulse signal. Magnetic disk device.