JPH05101515A - Flexible disk device - Google Patents

Abstract

PURPOSE:To prevent unnecessary power consumption by driving a stepping motor with a high voltage only in the period of rotation and oscillation of a stepping motor. CONSTITUTION:A stepping motor 9 receives a step signal 6 from a host device 8 and is rotated. An amplifier 2 amplifies the signal which is reproduced from a magnetic recording medium by a magnetic head 1. An envelope detector 3 detects the envelope of the output signal of the amplifier 2. A DC component eliminator 4 eliminates a DC component from the envelope detection output signal to output only an AC component. A comparator 5 compares the inputted AC component signal with a preliminarily determined reference level and outputs the AC component signal exceeding the reference level as a logical level. The stepping motor 9, is driven and controlled by a high power signal 7 only when the logical level output signal is in the high level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive circuit for a stepping motor having a function of switching a drive voltage of a flexible disk device between high voltage and low voltage, and more particularly to generation of a signal for switching between high voltage and low voltage.

[0002]

2. Description of the Related Art A conventional flexible disk drive has a monostable multivibrator 51 connected to a step signal sent from a host device 8 as a drive voltage switching signal generating circuit in a stepping motor drive circuit as shown in FIG. Was. As shown in FIG. 10, the operation of this circuit is that when the step signal 6 is sent from the host device 8 to rotate the stepping motor 9, the monostable multivibrator 51 outputs a pulse for a certain period of time at the rising edge of the signal, This output is used as the high power signal 7, and the steppins motor 9 is driven at a high voltage during this period. Before and after this, it is driven at a low voltage. The stepping motor 9 rotates for one step at the rising edge of the step pulse. That is, it is driven at a high voltage during rotation and at a low voltage during stop.

[0003]

In this conventional stepping motor drive circuit, the high voltage drive time is a predetermined constant time. Therefore, the high-voltage drive time must be set to the longest time for one step in consideration of the torque variation of the stepping motor and the load variation. Therefore, the conventional stepping motor has disadvantages that the high voltage driving time is long and the power consumption is large, which is unnecessary.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flexible disk device which drives a stepping motor at a high voltage only during rotation and vibration of the stepping motor to prevent unnecessary power consumption.

[0005]

In the flexible disk device of the first invention, magnetic recording is carried out in a stepping motor drive circuit in a flexible disk device having a function of switching the drive voltage of the stepping motor between high voltage and low voltage. A detector that detects the envelope of the signal reproduced from the medium, a DC component remover that is connected to this detector to remove the DC component from the detected output signal and removes only the AC component, and is connected to this DC component remover. A comparator for generating a high voltage drive signal for driving the stepping motor when the AC component signal is equal to or higher than a certain voltage.

The flexible disk device of the second invention is connected to the winding of the stepping motor and detects a counter electromotive force generated when the stepping motor rotates, and a counter electromotive force detection circuit. A comparator that is connected and generates a signal of a logic level when the back electromotive force detection signal is equal to or higher than a predetermined voltage, and a pulse width of a logic level output that is connected to the comparator and removes pulses having a pulse width of a predetermined time or less A monostable multivibrator for generating a high voltage drive signal for driving.

A flexible disk device according to a third aspect of the present invention is a frequency generator connected to a stepping motor shaft to generate an AC signal having a frequency proportional to a line speed, and an envelope of a power generation output signal connected to the frequency generator. And an envelope detector that detects the signal and a comparator that is connected to the envelope detector and that generates a high voltage drive signal for driving the stepping motor when the detected output is equal to or higher than a certain voltage.

A flexible disk device according to a fourth aspect of the present invention is an encoder connected to a stepping motor shaft to generate a pulse proportional to a rotation angle of the stepping motor, and an encoder connected to the encoder to remove a DC component of an encoder output signal. DC component remover for only components, a comparator connected to this DC component remover to generate a signal of a logical level when the AC component signal is a certain voltage or more, and a pulse output from the comparator connected to this comparator A monostable multivibrator for removing a pulse having a width equal to or shorter than a certain time and generating a high voltage drive signal for driving the stepping motor.

[0009]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of the first embodiment of the present invention.
The magnetic head 1 reproduces a signal from a magnetically recorded medium. This signal is amplified by the amplifier 2. The envelope detector 3 envelope-detects the output of the amplifier 2. The DC component remover 4 removes the DC component of this detection output signal and outputs only the AC component. The comparator 5 compares the AC component signal with the ground level, and outputs a high power signal 6 which becomes high level when the input is above the ground level. The high power signal 6 is a signal indicating a high voltage at a high level.

Next, the operation will be described with reference to the waveforms of each part in FIG. When the step signal 6 is sent from the host device 8, the stepping motor 9 rotates at the rising edge, and the magnetic head 1 moves onto the magnetically recorded track on the medium.
Then, the output b of the amplifier 2 starts to be output. This output begins to appear from the beginning when the magnetic head 1 hits the track and reaches its maximum when the magnetic head 1 moves to the track. The rotation of the stepping motor 9 ends here, but the vibration remains for a while. The output of the amplifier 2 reflects the above operation.

The envelope detector 3 detects the envelope of the output of the amplifier 2, and the detected output c becomes only the AC component by the DC component remover 4. The AC component output d is generated as a high power signal 7 by the comparator 5. The high power signal 7 drives the stepping motor 9 at a high voltage when it is at a high level. When the vibration of the magnetic head 1 subsides, the output b of the amplifier 2 becomes a constant level, the high power signal 7 also becomes a low level, and the stepping motor is driven at a low voltage.

FIG. 3 is a block diagram of the second embodiment of the present invention. The counter electromotive force detection circuit 21 detects the counter electromotive force generated when the stepping motor 9 rotates. Comparator 2
2 outputs a high level when the input voltage is higher than the ground level. The monostable multivibrator 23 outputs a pulse for a certain period when the input signal rises from low level to high level. During this pulse output period, the internal signal is reset when the input signal is input again, and the pulse is output for a certain period from the rising edge of the input signal input later. Therefore, when a signal that repeats high and low is input, the high level is maintained for a certain period from the first rising of the input signal to the last rising.

Next, the operation will be described with reference to the waveforms of the respective parts in FIG. When the step signal 6 is sent from the host device 8,
The stepping motor 9 rotates, and the counter electromotive force detection circuit 21
Produces an output e proportional to the motor rotation speed. This output waveform e is the movement for one step and the vibration thereafter.
The counter electromotive force detection signal is input to the comparator 22, is compared with the reference level (ground level), and outputs the comparator output f that becomes high level in the positive portion of the counter electromotive force. When this comparison output f is input to the monostable multivibrator 23, it becomes a continuous high level power signal 7. The high level occurs while the above stepping motor 9 is rotating and vibrating. When the vibration converges, the back electromotive force detection circuit 2
The output of 1 disappears, and the high power signal 7 also becomes low level.

FIG. 5 is a block diagram of the third embodiment of the present invention. The frequency generator 31 is connected to the stepping motor shaft and outputs a voltage / frequency proportional to the rotation speed of the stepping motor 9. The envelope detector 32 is
The envelope of the frequency generator output is detected and input to the comparator 33. The comparator 33 outputs a high level when the input envelope detection output is above the ground level.

Next, the operation will be described with reference to the waveform charts of the respective parts in FIG. When the step signal 6 is input from the host device 8, the stepping motor 9 rotates one step, and the frequency generator outputs a voltage / frequency g proportional to the rotation speed. The envelope detector 32 envelope-detects the frequency generator output g, inputs the envelope detection output h to the comparator 33, and the comparator 33 generates the high power signal 7.

FIG. 7 is a block diagram of the fourth embodiment of the present invention. The encoder 41 outputs a pulse proportional to the rotation angle of the stepping motor 9. DC component remover 42,
The comparator 43 and the monostable multivibrator 44 have the same functions as those described above.

Next, the operation will be described with reference to the waveforms of the respective parts in FIG. When the step signal 6 is input from the host device 8, the stepping motor 9 rotates for one step. The encoder 41 outputs in response to the rotation and vibration of the stepping motor 9. The encoder output i is passed through the DC component remover 42 to remove the DC component and become only the AC component, and the output remains only during rotation and vibration. This AC component output j becomes a logic level signal by passing through the comparator 43. When the comparator output k of this logic level is passed through the monostable multivibrator 44, a signal of high level is obtained during rotation and vibration without a thin pulse, and this signal is used as the high power signal 7.

[0018]

As described above, according to the present invention, since the high voltage drive is performed only during the rotation and vibration of the stepping motor, it is possible to prevent unnecessary power consumption.

[Brief description of drawings]

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

FIG. 2 is a waveform diagram for explaining the operation of the embodiment of the first invention.

FIG. 3 is a block diagram showing an embodiment of the second invention of the present invention.

FIG. 4 is a waveform chart for explaining the operation of the embodiment of the second invention.

FIG. 5 is a block diagram showing an embodiment of the third invention of the present invention.

FIG. 6 is a waveform diagram illustrating the operation of the third embodiment of the invention.

FIG. 7 is a block diagram showing an embodiment of the fourth invention of the present invention.

FIG. 8 is a waveform diagram illustrating the operation of the fourth embodiment of the invention.

FIG. 9 is a block diagram of a conventional flexible disk device.

FIG. 10 is a waveform diagram for explaining the operation of the conventional flexible disk device.

[Explanation of symbols]

 1 Magnetic Head 2 Amplifier 3,32 Envelope Detector 4,42 DC Component Remover 5,22,33,43 Comparator 6 High Power Signal 7 Step Signal 8 Host Device 9 Stepping Motor 21 Back Electromotive Force Detection Circuit 23,44 , 51 Monostable multivibrator 31 Frequency generator 41 Encoder

Claims (4)

[Claims] 1. A detector for envelope-detecting a signal reproduced from a magnetically recorded medium in a drive circuit of a stepping motor in a flexible disk device having a function of switching the drive voltage of the stepping motor between a high voltage and a low voltage. , A DC component remover connected to this detector to remove the DC component from the detection output signal and extract only the AC component,
A flexible disk device, comprising: a comparator connected to the DC component remover to generate a high-voltage drive signal for driving the stepping motor when the AC component signal is equal to or higher than a certain voltage. 2. A stepping motor driving circuit in a flexible disk device having a function of switching a driving voltage of a stepping motor between a high voltage and a low voltage, which is connected to a winding of the stepping motor and which is generated when the stepping motor rotates. A back electromotive force detection circuit for detecting an electromotive force, a comparator connected to the back electromotive force detection circuit for generating a signal of a logic level when the back electromotive force detection signal is equal to or higher than a certain voltage, and connected to this comparator. A flexible disk device, comprising: a monostable multivibrator for removing a pulse having a pulse width of a logic level output of a predetermined time or less and generating a high voltage drive signal for driving the stepping motor. 3. A stepping motor driving circuit in a flexible disk device having a function of switching the driving voltage of the stepping motor between high voltage and low voltage, which is connected to the stepping motor shaft and generates an AC signal having a frequency proportional to the line speed. A frequency generator, an envelope detector connected to the frequency generator to detect the envelope of the power generation output signal, and connected to the envelope detector to drive the stepping motor when the detection output is a certain voltage or more. And a comparator for generating a high-voltage drive signal for operating the flexible disk device. 4. A stepping motor drive circuit in a flexible disk device having a function of switching a stepping motor drive voltage between a high voltage and a low voltage, which is connected to a stepping motor shaft and generates a pulse proportional to a rotation angle of the stepping motor. An encoder, a DC component remover that is connected to this encoder and removes the DC component of the encoder output signal to leave only an AC component, and a DC component remover that is connected to this DC component remover A comparator that generates a signal, and a monostable multivibrator that is connected to this comparator and that generates a high voltage drive signal for driving the stepping motor by removing a pulse having a pulse width of a comparator output of a fixed time or less. A flexible disk device having.