JPS62217899A - Stepping motor drive system - Google Patents

Abstract

PURPOSE:To attenuate vibration rapidly at a stop state and to decrease setting time, by a method wherein slope wave voltage is applied at the stop state. CONSTITUTION:At a sequence state (at rotation of a stepping motor), a change- over switch (A) 7 is turned on, and signals from a pulse wave generator 4 and an electric damping wave generating circuit 3 are composed by a wave composite circuit 5, and a pulse wave signal composed there is applied to motor drive circuits 9, 10. At stop state, a change-over switch (B) 8 is turned on, slope waveform from a slope wave generator 6 is applied to the motor drive circuits 9, 10 and the stepping motor is rotated slowly so that vibration does not occur.

Description

[Detailed description of the invention] [Technical valve of the invention! 'F) The present invention relates to a stepping motor drive system for a magnetic disk device that uses a stepping motor as a head drive mechanism.

[Technical background of the invention and its problems]

In order to make the device smaller and cheaper, there is a magnetic disk device that uses a stepping motor as a head drive mechanism.

(The magnetic disk device in the present invention includes a floppy disk device and a hard disk device.) To move the head of the magnetic disk device and select a track, a step-like pulse voltage is applied to a stepping motor. However, normally the motor rotates in steps even after the head has stopped on the selected track.

For a while, the motor will vibrate and the rack will be slightly misaligned, so during this period, it will not be possible to send write signals to the head or read signals from the head.This period is called the settling time. I'm here. In order to reduce the vibration when the motor stops and shorten the settling time, electrical damping is applied, such as by instantaneously applying pulses, so that the remoter rotates in the opposite direction to the mechanically damped remoter rotation. There is a way to do this.

Electrical damping requires applying a reverse pulse at a good time in synchronization with the vibration mode, but in order to increase the track density, the stop position of the stepper motor must be simply set at one point.
Not only phase or 2-phase but also 1-phase and 2-phase, both positions.
It is often done to stop. However, from the viewpoint of adding the electric damping mentioned above, this method is not very desirable.In other words, the mode of vibration during stop is different between 1-phase and 2-phase, so when applying electric damping, It is necessary to apply electrical signals that meet the damping conditions corresponding to each phase. Furthermore, since different vibrations in the one-phase and two-phase modes are superimposed, there is also the drawback that even if electric damping is applied, it is difficult to apply damping compared to the case of single-phase or two-phase driving. Furthermore, damping conditions for each phase must be stored in a memory or the like, which has the disadvantage of complicating the electrical circuit.

[Purpose of the invention]

This invention improves the drawbacks of the prior art described above.
To provide a driving system for a magnetic disk stepping motor that can increase track density by using both one-phase and two-phase, although electric damping is easy to apply and the circuit is simple.

[Summary of the invention]

This invention uses only one phase or two phases to drive during seek (when the stepping motor rotates), simultaneously applies electric damping under damping conditions suitable for that phase, and moves to the final stop phase. Sometimes, instead of applying the drive voltage in steps, a slope waveform voltage that rises or falls slowly to the extent that no vibration occurs is applied, and the voltage is stopped at a target phase.

〔Effect of the invention〕

According to this invention, electric damping can be effectively applied without complicating the circuit, so the device can also be inexpensive. Furthermore, by properly applying electric damping, the settling time can be shortened, and an apparatus with a fast seek time as a whole can be manufactured.

[Embodiments of the invention]

FIG. 1 shows a block diagram of a stepping motor drive circuit according to the present invention. Data specifying the number of tracks to be moved is input to the control circuit (2) from the external terminal (2). In the control circuit ■, follow these instructions to create the electric damping waveform generation circuit ■.

pulse waveform generation circuit), slope waveform generation circuit 0° changeover switch (A) ■, changeover switch (B) ■ to drive the motor drive circuit (A) (9), motor drive circuit (B) (
10) Generate a driving voltage to be applied to. The motor drive circuit (A) (9) and the motor drive circuit (B) (to) apply current to the motor winding (A) (11) and motor winding (B) (12) according to the drive voltage to drive the motor. Rotate.

FIG. 2 shows a stepper motor drive system according to the present invention. This figure shows the relationship between the stepper motor applied voltage and the magnetic head track position. In this figure, the stepping motor winding is assumed to be bipolar, and the voltage waveform used to drive it is shown. First, the electric damping conditions are constant. During the T□ period, the stepping motor is also driven by only one phase.

The applied voltage indicates the applied voltage for one-phase drive, and the applied voltage during this period also includes an electric damping signal indicated by diagonal lines (21) for each step. The method of applying electric damping No. 4n will not be described in detail since it is not the gist of the present invention, but a voltage that cancels vibrations when the stepping motor is stopped is applied immediately before the stepping motor is stopped.

These driving voltages and electric damping signals during the T1 period are generated by the pulse waveform generating circuit shown in FIG.
passing through the motor drive circuits (A) and Q and the motor drive circuit (
B) applied to (10).

That is, during the TL period, the changeover switch (A) ■ is ON, and the changeover switch (B) 8 is OFF. Also, during the 'r1 period, one phase is fed, so originally the 1-
If the device is designed to move one track at a time with two-phase feed, it will move two tracks at a time. If the final track is in one phase, it is sufficient to just stop it as shown by the dotted line (22), since electric damping is applied.

The vibration at the time of stopping ends in about 2 tracks. On the other hand, if the final track is 2-phase.

If one track was driven by a pulse voltage in the same way as the previous track, the vibration of the one-phase feed during the T□ period and the vibration of the new two-phase feed would be combined, making the conditions for electric damping complicated.

Since damping is less likely to occur, vibrations during stopping will not subside within 2 steps.
When the motor is driven in phase and the final stop position is 2 phases, the applied voltage is applied not in a step pattern but in a slope pattern (23) as shown in the T2 period, and the stepping motor is also applied slowly to avoid vibration. (slowly track the head). In this way, the vibrations during 1-phase feeding have already been damped, so the lead or lie 1-operation can be started immediately.

As described above, when the stepping motor drive method of the present invention is used, the vibrations when the stepping motor is stopped are quickly attenuated, so that the overall seek time can be shortened.

[Other embodiments of the invention]

In the embodiment of the present invention, an example is shown in which the phase is fed in a stepwise manner using only one phase, but conversely, it may be fed using only two phases or other phases such as an intermediate phase. At this time, when the final stop position is one phase or another phase that is not being fed in steps, a slope voltage is applied to stop it.

Although FIG. 2 shows a gently rising waveform as a slope waveform, a triangular wave may also be used.

Further, in the embodiment, the applied waveform is a voltage, but it may be driven with a constant current waveform having a similar configuration.

Furthermore, although the present invention has been described as an example of driving a stepping motor of a magnetic disk device, it is of course applicable to other devices using a stepping motor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a stepping motor drive circuit for a magnetic disk device according to the present invention, and FIG. 2 is a diagram showing voltage waveforms applied to the stepping motor and track movement states. 2... Control circuit 4... Pulse waveform generation circuit 6
... Slope waveform generation circuit 23 ... Slope waveform agent Patent attorney Nori Chika Ken Yudo Kikuo Takehana Figure 1

Claims (2)

[Claims] (1) In a magnetic disk device that uses a stepping motor as the head drive mechanism, when the stepping motor is stopped in multiple phases such as 1-phase, 2-phase, etc., only one type of stop position is used when moving until reaching the target track. A stepping motor drive method characterized in that a stepping motor is driven in a phase, and at the same time electric damping is applied under damping conditions suitable for that phase, and only the last step is stopped in an arbitrary phase. (2) When driving a stepping motor with only one type of phase, the driving voltage is applied in steps, and the driving voltage is applied in a slope only in the last step. The stepping motor drive method described in item 1.