JPH06311781A - Disk drive - Google Patents

Abstract

PURPOSE:To make it possible to continuously run a highly accurate Hall motor, used as a spindle motor, even in the case of faults of its Hall element by using counterelectromotive force as rotation control information to control the motor rotation. CONSTITUTION:The title disk drive uses a direct current motor as a spindle motor 10, which is therein provided with a Hall element HA. The rotation is controlled by a MPU 13 for motor control using the output of the Hall element HA as rotation control information. The disk drive also includes a counter electromotive force detecting circuit 16 for detecting the counterelectromotive force of the motor coil. The motor control MPU 13 is provided with a switching section 19, which selects the output of the Hall element when it is normal and the counterelectromotive force signal from the counter electromotive force detecting circuit 16 when the Hall element HA is anomalous. If the Hall element HA is anomalous condition, as mentioned above, the counterelectromotive force signal is used for rotation control information instead of the output of the Hall element, and the control of the spindle motor 10 rotation is thereby feasible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a spindle motor (DC motor) for rotating a disk (magnetic recording medium) and a motor control MPU, and a hall element is provided inside the spindle motor. The present invention relates to a disk device that controls the rotation of a spindle motor using the output of a Hall element as rotation control information.

[0002]

2. Description of the Related Art FIG. 7 is an explanatory diagram of a conventional example 1, and FIG. 8 is an explanatory diagram of a conventional example 2. In FIGS. 7 and 8, 1 is a disk enclosure (Disk Encrosur: hereinafter referred to as “DE”), 2
Is a spindle, 3 is a magnetic disk (recording medium), 4 is a servo surface, 5 is a data surface, and 6 is a voice coil motor (Voic).
e Coil Motor: hereinafter referred to as “VCM”), 7 is an actuator, 8 is a servo head, 9 is a data head, 10 is a spindle motor (DC motor), 11 is a read / write control unit, 12 is a head positioning servo control unit, Reference numeral 13 is a motor control MPU (microprocessor), 14 is a Hall element output detection circuit, 15 is a motor drive circuit, and 16 is a back electromotive voltage detection circuit.

§1: Description of Conventional Example 1 ... See FIG. 7 Hereinafter, Conventional Example 1 will be described with reference to FIG. Conventional example 1
Is an example in which the spindle motor of the magnetic disk device is configured by a three-phase DC motor (also referred to as “Hall motor”) having a Hall element.

The spindle motor 10 includes three Hall elements Ha (A phase) and Hb (B) as position detecting elements.
Phase) and Hc (C phase) are provided for each phase. The hall element output detection circuit 14 is a circuit that detects the output of the hall element, shapes the waveform, and converts the output into a rectangular wave signal.

The motor control MPU 13 outputs a signal from the hall element detection circuit 14 (hall element output signal).
Is used as rotation control information, and a motor control signal (for example, PW
The M signal) is generated and sent to the motor drive circuit 15 to control the spindle motor 10.

The motor drive circuit 15 is a motor control MP.
The spindle motor 10 is controlled by a motor control signal (PWM signal) from U13, and a current is passed through the spindle motor 10 to rotationally drive the spindle motor.

Further, the DE 1 is provided with a plurality of magnetic disks (recording media) 3 which are coupled to the spindle 2 and rotated by the spindle motor 10. The servo surface 4 is provided on one surface of any one of the plurality of magnetic disks 3, and the surfaces of the other magnetic disks 3 are all data surfaces 5.

An actuator (head actuator) 7 driven by the VCM 6 is provided with a plurality of magnetic heads via a head arm. Of these magnetic heads, the magnetic head on the servo surface 4 side is the servo head 8 and all the magnetic heads on the data surface 5 side are the data heads 9.

The servo head 8 reads the servo information on the servo surface 4, and the read servo information is sent to the head positioning servo control unit 12 to be used as information for head positioning control.

The data head 9 reads / writes data from / to the data surface 5, and the read / write controller 11 controls read / write data.

The VCM 6 is driven by the head positioning servo control unit 12 and moves the data head 9 and the servo head 8 in the radial direction of the magnetic disk 3 via the actuator 7.

§1: Description of Conventional Example 2 ... See FIG. 8 Hereinafter, Conventional Example 2 will be described with reference to FIG. Conventional example 2
Is an example in which the spindle motor of the magnetic disk device is configured by a three-phase DC motor whose rotation is controlled by using the counter electromotive voltage generated (induced) in the coil of the motor as rotation control information.

In this example, the back electromotive voltage detection circuit 16 is connected to the coils of each phase of the spindle motor 10, the back electromotive voltage generated in the coils is detected, converted into a rectangular wave signal, and output.

The motor control MPU 13 outputs a signal (back electromotive voltage signal) output from the back electromotive voltage detection circuit 16.
Is used as rotation control information, and a motor control signal (for example, PW
M signal) and sends it to the motor drive circuit 15.

The motor drive circuit 15 is a motor control MP.
Controlled by a motor control signal from U13, a current is passed through the spindle motor 10 to rotationally drive the spindle motor. Since the other configurations are the same as those of the conventional example 1 shown in FIG. 7, description thereof will be omitted.

[0016]

SUMMARY OF THE INVENTION The above-mentioned conventional devices have the following problems. : In the conventional disk device, the rotation control of the spindle motor is (a): a hall motor is used and the rotation control information is the hall element output (conventional example 1), or (b): the reverse of the motor. Only one of the rotation controls (conventional example 2) using the electromotive voltage as the rotation control information is performed.

However, in the case of performing the rotation control of the above (b), the rotation direction is not immediately determined at the time of start-up because the motor does not generate a counter electromotive voltage unless the rotation speed increases to some extent.

Further, when the number of rotations is such that no back electromotive force is generated, it is not possible to confirm whether it is rotating or stopped. Therefore, in this respect, the control of (b) above is
It was inferior to the control of (a).

For this reason, normally, a hall motor capable of highly precise control (see Conventional Example 1) is used. However, if the hall element fails, after that, the hall element is repaired (or replaced). Until then, the motor could not be rotated normally.

Further, if the Hall element fails, the read / write data may be destroyed and continuous processing may not be possible. : A spindle motor equipped with a hall element (hall motor) cannot rotate normally when a failure of the hall element occurs. As a countermeasure for this, it is possible to provide a spare Hall element, but in reality, it is impossible because there is no mounting space.

Further, even if a spare Hall element is attached, the same signal waveform cannot be obtained because the attachment position is different from that of the regular Hall element. Therefore, as described above, it is actually impossible to provide a spare Hall element.

The present invention solves such a conventional problem, uses a hall motor (motor having a hall element) capable of highly accurate rotation control as a spindle motor, and when the hall element fails, An object of the present invention is to continuously rotate the spindle motor by performing rotation control using the back electromotive voltage as rotation control information.

[0023]

FIG. 1 is a diagram for explaining the principle of the present invention. In FIG. 1, the same parts as those in FIGS. 7 and 8 are designated by the same reference numerals. Further, 19 is a selection unit, 20 is a motor rotation control unit, 21 is an R / W (read / write) data register, 22 is a non-volatile memory, 23 is an I / F (interface) control unit, and 24 is a Hall element abnormality. The detection circuit is shown.

In order to solve the above problems, the present invention has the following constitution. A spindle motor 10 for rotating the magnetic disk 3 and a motor control MPU 13 for controlling the rotation of the spindle motor 10 are provided, the spindle motor 10 is a DC motor, and a hole for a position detecting sensor is provided inside the spindle motor 10. Element HA is provided, and MPU1 for motor control
In the disk device that controls the rotation of the spindle motor by using the output of the Hall element HA as the rotation control information according to 3, the counter electromotive voltage detection circuit 16 that detects the counter electromotive voltage generated in the coil of the spindle motor 10 is described.
Is connected to the motor control MPU 13, the hall element output is selected when the hall element HA is normal, and the counter electromotive voltage signal from the counter electromotive voltage detection circuit 16 is selected when the hall element is abnormal. The selection unit 19 is provided to select the counter electromotive voltage signal as the rotation control information instead of the output of the Hall element when the Hall element is abnormal, thereby enabling the rotation control of the spindle motor.

A Hall device abnormality detection circuit 24 for detecting an abnormality of the Hall element HA is provided in the disk device having the configuration, and when the Hall element abnormality detection circuit 24 detects an abnormality of the Hall element HA, an alarm signal AL is output as a motor. By notifying the control MPU 13, the motor control MPU 13 can recognize whether the hall element HA is normal or abnormal.

A non-volatile memory 22 accessible to the motor control MPU 13 is provided in the disk device having the structure, and when the Hall element HA becomes abnormal during the data read / write operation, the motor control MPU 13 is ,
The read / write data is configured to be stored in the nonvolatile memory 22.

When the spindle motor 10 having the structure is restarted after the rotation is stopped due to the abnormality of the Hall element, the back electromotive force signal is restarted as the rotation control information to read the data stored in the nonvolatile memory 22 to detect the abnormality of the Hall element. It was configured to be able to continue the work when it occurred.

[0028]

The operation of the present invention based on the above configuration will be described with reference to FIG. : Hall element is normal When the normal rotation control is performed on the spindle motor, the hall element HA is operating normally, and therefore the spindle motor rotation control is as follows.

The hall element abnormality detection circuit 24 detects that the hall element is normal based on the output state of the hall element HA incorporated in the spindle motor 10. Then, in the hall element abnormality detection circuit 24, the motor control M
The PU 13 is notified of information (alarm signal AL = low level L) indicating that “the hall element is normal”. At this time, the motor control MPU 13 selects the Hall element output by the selection unit 19.

In the motor rotation control unit 20, based on the rotation control information (Hall element output) selected by the selection unit 19,
The rotation control of the spindle motor 10 is performed. Then, the motor drive circuit 15 is controlled by a control signal (for example, a PWM signal) from the motor rotation control unit 20 to rotationally drive the spindle motor 10.

Further, when the magnetic disk device is in a read or write state, the data in the R / W data register 21 for temporarily storing read / write data is transferred as follows.

At the time of reading, the data is sent from the R / W data register 21 to the interface control unit 23 as it is, and at the time of writing, the data is transferred from the R / W data register 21 to the read / write control unit 11 as it is. To do.

However, if the hall element HA fails for some reason, the hall element abnormality detection circuit 24 detects this state, and the motor control MPU 13 is informed of the "hall element". Is abnormal ”(alarm signal AL = high level H).

The motor control MPU 13 recognizes from the notification that the Hall element has failed. At this time, the motor control MPU 13 performs control to stop the rotation of the spindle motor 10 if the spindle motor 10 is rotating.

When the spindle motor 10 is stopped by this control, in the motor control MPU 13, the selection unit 19
To switch the counter electromotive voltage signal. By this selection, the motor rotation control unit 20 controls the spindle motor 10 according to the rotation control information (back electromotive voltage signal) selected by the selection unit 19. Then, the motor rotation control unit 20 controls the motor drive circuit 15 to rotate the spindle motor 10.

As described above, if the magnetic disk device is in the read or write state when the Hall element fails, the data in the R / W data register 21 is non-volatile in the motor control MPU 13. The memory 22.

In this case, whether it is a read or a write is written in the non-volatile memory 22.
After that, the motor control MPU 13 notifies the interface control unit 23 that there is an abnormality, and controls the stop of the spindle motor 10 as described above.

At the time of restarting after the Hall element has failed, the motor control MPU 13 controls the rotation of the spindle motor 10 from the beginning. In this case, the spindle motor is controlled based on the information on the counter electromotive voltage. 10 rotation control is performed.

Further, when the spindle motor 10 is restarted after the rotation is stopped due to the abnormality of the hall element, the back electromotive force signal is restarted as the rotation control information, the hall element abnormality is generated by reading the data stored in the nonvolatile memory 22. Continue the work of time.

As described above, a hall motor (motor having a hall element) capable of highly precise rotation control is used as the spindle motor, and the counter electromotive voltage is used as rotation control information even when the hall element fails. By performing the control, the spindle motor can be continuously rotatable.

[0041]

Embodiments of the present invention will be described below with reference to the drawings. 2 to 6 are views showing an embodiment of the present invention. In FIGS. 2 to 6, the same parts as those in FIGS. 1, 7, and 8 are designated by the same reference numerals. Also, 17 is a motor coil, 25
Is an EEPROM (Electrically Erasable Programmable
Read Only Memory), 26 is a Hall element output register, 27 is a counter electromotive voltage signal register, 28 is a speed control unit, 29 is a drive current phase switching unit, 31 is an AND gate, 32 is a NOR gate, and 33 is an OR gate. , 34 are comparators, and Ha, Hb, and Hc are Hall elements.

§1: Description of the configuration of the magnetic disk device
-Refer to FIG. 2 FIG. 2 is a configuration diagram of the magnetic disk device. In this embodiment, as the spindle motor 10 of the magnetic disk device,
In this example, a three-phase (A phase, B phase, C phase) DC (direct current) motor is used.

Since the configuration of the DE (disk enclosure) 1 shown in FIGS. 7 and 8 is the same in this embodiment, details are omitted. In this embodiment, the magnetic disk device includes a DE 1, a read / write control unit 11, a motor control MPU 13, a Hall element output detection circuit 14,
Back electromotive force detection circuit 16, Hall element abnormality detection circuit 24,
An I / F control unit 23, an EEPROM 25, a motor drive circuit 15 and the like are provided.

Further, the DE 1 is provided with a spindle motor 10, a spindle 2, a magnetic disk 3, a data head 9 and the like as in the conventional example shown in FIGS. However, the spindle motor 10 of this embodiment (which is located below the magnetic disk 3 in FIG. 2 and is shown by a dotted line) performs rotation control by using the information from the Hall element as rotation control information, and the motor coil. The counter electromotive force generated at the rotation control information is used as the rotation control information to control the rotation.

Therefore, the spindle motor 10 has three Hall elements Ha, Hb, and
Hc is provided (built into the motor). In this case, three Hall elements Ha, Hb, Hc are provided corresponding to each phase (A phase, B phase, C phase) of the spindle motor 10,
These Hall elements include the Hall element output detection circuit 14
Are connected (same as the configuration of FIG. 7).

A counter electromotive voltage detection circuit 16 is connected to the coil 17 of the spindle motor 10 in order to detect a counter electromotive voltage (back electromotive force) generated in the coil 17 (see FIG. 8). Same configuration).

The functions and the like of the above-mentioned respective parts are as follows. (1): The hall element output detection circuit 14 is a hall element H.
It is a circuit that detects the output signals of a, Hb, and Hc, shapes the waveform, and converts the waveform into a rectangular wave.

(2): The counter electromotive voltage detection circuit 16 is a circuit for detecting the counter electromotive voltage (sinusoidal voltage) generated in the coil 17 of the spindle motor 10 and converting it into a rectangular wave. (3): The hall element abnormality detection circuit 24 is a circuit that detects an abnormality (fault) of the hall element based on the output signal of the hall element output detection circuit 14.

The hall element abnormality detection signal output from this circuit is notified to the motor control MPU 13 as an alarm signal AL. (4): The motor control MPU 13 is a processor that controls the rotation of the spindle motor 10.

(5): The read / write controller 11 controls the data to be read / written from / to the magnetic disk 3 by the data head 9. (6): The EEPROM 25 is the MPU 13 for motor control.
It is a non-volatile memory that is read / written by.

(7): The I / F controller 23 controls various interfaces with the host controller. (8): The motor drive circuit 15 is the MPU 1 for motor control.
3 is a circuit that drives the spindle motor 10 to rotate based on a control signal from the controller 3.

(9): The R / W data register 21 is
This is a register for temporarily storing data to be read / written to / from the disk 3. (10): The hall element output register 26 is a register for temporarily storing the output signal of the hall element output detection circuit 14.

(11): Back electromotive force signal register 27
Is a register for temporarily storing the output signal of the counter electromotive voltage detection circuit 16. (12): The selection unit 19 includes the hall element abnormality detection circuit 24.
Switching is controlled by a signal (alarm signal AL) output from the device, and when the hall element is normal (A
L = L) is a circuit for selecting the signal of the hall element output register 26, and when the hall element is abnormal (AL = H), it is a circuit for selecting and outputting the signal of the counter electromotive voltage signal register 27.

(13): The speed control unit 28 has the selection unit 19
The speed control of the spindle motor is performed on the basis of the one-phase signal (for example, the A-phase signal) of the rotation control information selected in. In this example, the speed of the spindle motor is controlled by PWM (pulse width modulation) control.

(14): The drive current phase switching unit 29 is
The rotation control information (A phase, B phase, C) selected by the selection unit 19
Phase), switching control of the drive current phase of the spindle motor 10 is performed.

The speed control section 28 and the drive current phase switching section 29 correspond to the motor rotation control section 20 of FIG. §2: Description of Hall element abnormality detection circuit ... See FIG. 3. FIG. 3 is an explanatory diagram of the Hall element abnormality detection circuit.
FIG. 3A is an example of a Hall element abnormality detection circuit, and FIG. 3C is an explanatory diagram when a Hall element abnormality is detected.

The Hall element output shown in FIG. 3A is
This is a signal (a signal shaped into a rectangular wave) output from the Hall element output detection circuit 14 when the Hall element is operating normally.

In this case, in FIG. 3A, the signal output from the Hall element output detection circuit 14 (the signal shaped into a rectangular wave) is: the output of the Hall element Ha (the output of the A phase),
: Hall element Hb output (B-phase output): Hall element Hc output (C-phase output)

Further, t0 to t6 indicate each timing (time), "H" indicates a high level and "L" indicates a low level. For example, between t0 and t1, Ha output = H,
Hb output = H, Hc output = L, H between t1 and t2
a output = H, Hb output = L, Hc output = L, t2 to t3
Between, Ha output = H, Hb output = L, Hc output =
Between H and t3 to t4, Ha output = L, Hb output =
L, Hc output = H, ...

To detect the abnormality of the hall element from the signal changing in this way, the hall element abnormality detection circuit 24 shown in FIG. 3B is used. In this example, the hall element abnormality detection circuit 24 includes an AND gate 31 and a NOR gate 3.
2 and an OR gate 33.

The input signals of the Hall element abnormality detection circuit 24 are the signals of and shown in FIG. 3A, and the output signal is indicated by AL (alarm signal). At the time of detecting an abnormality of the hall element, as shown in FIG. 3C, the output signal A
L changes from L to H (alarm state when alarm signal AL = H).

That is, when all the Hall elements are normal, H and L signals are included between the above timings, and the output signal AL is always L. For example, t0 to t
Between 1, the Ha output = H, the Hb output = H, the Hc output =
Since it is L, the output of the AND gate 31 is L, the output of the NOR gate 32 is L, and the output signal AL (alarm signal) is AL = L.

Further, during t1 to t2, Ha output =
Since H, Hb output = L, and Hc output = L, the output of the AND gate 31 is L, the output of the NOR gate 32 is L, and the output signal AL is AL = L.

Further, between t2 and t3, Ha output =
Since H, Hb output = L, and Hc output = H, the output of the AND gate 31 is L, the output of the NOR gate 32 is L, and the output signal AL is AL = L.

Thus, if the Hall element is normal,
The output signal AL of the hall element abnormality detection circuit 24 is always L
Has become. However, when a failure occurs in the Hall element, the signals of and shown in FIG. 3A remain H or L (the state in which the Hall element fails due to destruction or the like and cannot perform the position detecting function). , Always H or L
It will be in the state of).

Therefore, as shown in FIG. 3C, the output signal AL of the hall element abnormality detection circuit 24 is always in the H state. Hereinafter, this point will be described in detail. For example, it is assumed that the: Ha output,: Hb output, and: Hc output all become L when the Hall element fails.

In this case, the output of the AND gate 31 is
The output of the L and NOR gates 32 is H, and the OR gate 3
The output signal AL of 3 becomes AL = H. Also, when the Hall element fails,: Ha output,: Hb output,: Hc
It is assumed that all outputs have become H.

In this case, the output of the AND gate 31 is
The output of the H and NOR gates 32 is L, and the OR gate 3
The output signal AL of 3 becomes AL = H. As described above, the output signal AL of the hall element abnormality detection circuit 24 is A
If L = L, it is assumed that the Hall element is normal, and AL = H
If so, it is assumed that a failure has occurred in the Hall element.

This state is notified to the motor control MPU 13 and is recognized by the motor control MPU 13. §3: Description of back electromotive force detection circuit ... See FIG. 4. FIG. 4 is an explanatory diagram of the back electromotive force detection circuit. FIG. 4A is an example of the back electromotive force detection circuit, and FIG. / It is an output signal waveform diagram.

The counter electromotive voltage detection circuit 16 is a circuit for converting the counter electromotive voltage (sinusoidal signal) induced in the coil 17 of the spindle motor 10 into a rectangular wave signal. The counter electromotive voltage detection circuit 16 is composed of, for example, a comparator 34 as shown in FIG. 4A. Further, this circuit is provided for each phase (A phase, B phase, C phase) of the spindle motor 10, but FIG. 4A shows only one phase circuit. An inverter is provided on the output side of the B-phase comparator 34 (not shown). In FIG. 4, Vp
Are output voltages of A phase, B phase, and C phase (input voltage of the counter electromotive voltage detection circuit), Vr is a reference voltage, M is an output, and t0 to t9.
Indicates each timing (time). The B-phase output signal waveform M (* B-phase) is inverted by the inverter so as to have the same combination of waveforms as the Hall element output signal.

In the comparator 34 which constitutes the counter electromotive voltage detection circuit 16, the output voltage Vp of the A phase (B phase / C phase) is
It is compared with the reference voltage Vr, converted into a rectangular wave signal, and the output signal M is output.

As shown in FIG. 4B, the comparator 34
The output voltage Vp of the A phase (B phase / C phase) that is input to is a sinusoidal signal, and this voltage signal is used as a constant reference voltage V
The output signal M is compared with r.

For example, the output voltage Vp of the A phase is t0 to t
Since the reference voltage Vr is exceeded during the period of 3, M (A
Phase) = H and smaller than the reference voltage Vr between t3 and t6, M (A phase) = L and between t6 and t9 the reference voltage Vr is exceeded, so M (A phase) = H. Becomes

Further, since the output voltage Vp of the B phase is smaller than the reference voltage Vr from to t1, M (B phase) =
Since the reference voltage Vr is exceeded during L and t1 to t4, the reference voltage Vr is exceeded during M (B phase) = H and t4 to t7.
Since it is smaller than r, M (B phase) = H.

However, in the case of the B phase, the above M (B phase) is inverted by the inverter in order to obtain the same combination of signals as the Hall element output. In FIG. 4B, M (B phase) is shown as an inverted signal M (* B phase).

Therefore, M (* B phase) is M (* B phase) = H between t1 and t, and M (*) between t1 and t4.
B phase) = L, and between t4 and t7, M (* B phase) = L.

Further, since the output voltage M of the C phase is smaller than the reference voltage Vr from to t2, M (C phase) =
Since the reference voltage Vr is exceeded between L and t2 to t5, the reference voltage Vr is exceeded between M (C phase) = H and t5 to t8.
Since it is smaller than r, M (C phase) = L.

As described above, the Hall element output detection circuit 1
4 and the output signals M (A phase), M (* B phase), and M (C phase) of the counter electromotive voltage detection circuit 16 have the same combination of waveforms, the drive current phase switching unit 29,
The speed control unit 28 and the speed control unit 28 can be configured by a common circuit.

That is, the signals (rotation control information) selected by the selection unit 19 have the same combination of signal waveforms, whichever signal is selected by the drive current phase switching unit 29 and the speed control unit 28. Even if you select
The same rotation control information can be used for rotation control.

§4: Description of operation of magnetic disk device ...
Referring to FIG. 2, the operation of the magnetic disk device will be described below with reference to FIG. : Description of normal operation (when the hall element is normal) First, when performing normal rotation control, the hall element Ha,
Since Hb and Hc are operating normally, the flow of rotation control is as follows.

The hall element abnormality detection circuit 24 detects that the hall element is normal, based on the output states of the three hall elements Ha, Hb, and Hc incorporated in the spindle motor 10.

Then, the hall element abnormality detection circuit 24 notifies the motor control MPU 13 of information (AL = L) indicating that the hall element is normal. At this time,
The selection unit 19 of the motor control MPU 13 selects the signal (Hall element output) of the Hall element output register 26.

In the drive current phase switching unit 29, the selection unit 1
Based on the rotation control information selected in 9, the phase of the current flowing through the coil of the spindle motor 10 is switched. Further, the speed control unit 28 grasps the rotation speed of the spindle motor 10 based on the information from one Hall element (for example, Ha) among the three Hall elements, and according to the rotation speed at that time. , PWM waves are generated.

Then, the speed control section 28 and the drive current phase switching section 29 control the motor drive circuit 15 to rotate the spindle motor 10. Further, when the magnetic disk device is in the read or write state, the R / W data register 21 for temporarily storing the read / write data.
Data is transferred as follows.

At the time of reading, the data is sent from the R / W data register 21 to the interface controller 23 as it is, and at the time of writing, the data is transferred from the R / W data register 21 to the read / write controller 11 as it is. To do.

The read / write controller 11 sends the data received from the R / W data register 21 to the data head 9 and writes it on the magnetic disk 3. : Explanation when the Hall element is abnormal For some reason, the Hall element fails (element breakdown, etc.)
If so, the hall element abnormality detection circuit 24 detects this state and notifies the motor control MPU 13 that "the hall element is abnormal" (AL = H).

In the motor control MPU 13, if the spindle motor 10 is rotating when the Hall element is out of order, control is performed to stop the rotation of the spindle motor 10.

When the spindle motor 10 is stopped by this control, the motor control MPU 13 selects the selection unit 19
To switch the signal of the counter electromotive voltage signal register 27 to
Selected as rotation control information.

By this selection, the drive current phase switching unit 2
At 9, the control for switching the phase of the current flowing through the coil of the spindle motor 10 is performed based on the rotation control information selected by the selection unit 19.

In the speed controller 28, three phases (A phase,
The rotation speed is grasped from the waveform of the counter electromotive voltage of one phase (for example, the A phase) of the B phase and the C phase, and P is determined according to the rotation speed at that time.
Generate a WM signal.

Then, the drive current phase switching section 29 and the speed control section 28 control the motor drive circuit 15,
The spindle motor 10 is rotated. It should be noted that when the Hall element fails and the magnetic disk device is in a read or write state, the R / W data register 21
Of the data is written in the EEPROM 25. in this case,
When the Hall element fails, whether it was a read or a write is written in the EEPROM 25.

After that, the motor control MPU 13 notifies the interface control unit 23 that there is an abnormality, and controls the spindle motor 10 to stop as described above. And when restarting after the Hall element fails,
The motor control MPU 13 controls the rotation of the spindle motor 10 from the beginning. In this case, the rotation control of the spindle motor 10 is performed based on the information on the counter electromotive voltage.

§5: Process description of MPU for motor control
-Refer to FIG. 5 and FIG. 6. FIG. 5 and FIG. 6 are process flowcharts of the motor control MPU. Hereinafter, the process of the motor control MPU will be described with reference to FIGS. 5 and 6. In addition, S1-S15 of a figure show each process number.

S0: In this process, when the magnetic disk device is powered on (power-on), the Hall element H
It is determined whether or not a, Hb, and Hc are broken (whether they are broken or not).

In this case, in the motor control MPU 13,
Output signal AL of hall element abnormality detection circuit 24 (AL =
Judge by 0: normal, AL = 1: failure). In the processing of S1: S0, when it is determined that the Hall element is not broken down (not broken), the Hall element output is selected as the rotation control information.

At this time, the selection unit 1 receives the AL = 0 signal.
The selection by 9 is set to the Hall element output register 26 side. S2: In this process, following the process of S1, the motor control MPU 13 determines whether or not the spindle motor 10 is stopped.

If the spindle motor 10 is rotating (for example, if the spindle motor is stopped and controlled when the Hall element fails, but is not stopped yet), it waits until it is stopped.

S4: If it is determined in step S2 that the motor is stopped, the spindle motor 10 is started. At this time, the spindle motor 10 is controlled using the rotation control information from the Hall element output register 26 selected by the selection unit 19.

S3: When it is determined that the Hall element is broken (broken) in the process of S0, the counter electromotive voltage signal (output of the counter electromotive voltage detection circuit 16) is selected as the rotation control information. .

In this case, in the motor control MPU 13,
Alarm signal AL from hall element abnormality detection circuit 24
Confirm that AL = 1 (Hall element error),
The selection by the selection unit 19 by the signal AL = 1 is set to the counter electromotive voltage signal register 27 side.

S5: Following the processing of S3, wait for time n. In addition, this time n, from the steady rotation state of the motor,
It is the time until complete stop and is obtained in advance as an experimental value.

S6: Following the processing of S5, the spindle motor 10 is started. At this time, the spindle motor 10 is controlled using the signal from the counter electromotive voltage signal register 27 selected by the selection unit 19 as rotation control information.

S7: In this processing, the spindle motor 1
When 0 is started by S4 and is rotating, the output signal AL of the hall element abnormality detection circuit 24 (AL = 0: normal, A
L = 1: failure), it is determined whether or not the Hall elements Ha, Hb, Hc are broken (whether broken or not) (check during rotation of the spindle motor).

S8: When it is determined that the Hall element is normal in the processing of S7, the Hall element output is selected as the rotation control information, and the rotation control of the spindle motor is performed. In this case, the drive current phase switching unit 29 switches the drive current phase of the spindle motor 10 and the speed control unit 28 performs steady rotation control (PWM control).

S9: Following the processing of S8, EEPROM2
In 5, it is determined whether the write / read data is stored. As a result, when the write / read data is not stored, the above process S7 (when AL = 0),
Alternatively, the process returns to S8 (when AL = 1).

S10: In the processing of S9, the EEPROM 25
If the write / read data is stored in,
After the write / read process is interrupted due to a failure of the Hall element, the spindle motor 10 is restarted (AL = 1) using the counter electromotive voltage signal as rotation control information.

Therefore, at this time, the write / read processing (work) from the place where the operation was interrupted last time is continued. S11: When the processing of S10 ends, the EEPROM 25
Erase the data and return to S8 (when AL = 1).

S12: This process is performed when the Hall element is determined to be defective (broken) in the process of S7. In this process, the motor control MPU 13 causes the I / F control unit 2 to
Based on the information from 3, it is determined whether or not write / read is in progress.

S13: Write (WRITE) in the process of S12
If it is determined to be in the middle, the write data from the I / F control unit 23 is stored in the EEPROM 25. In this case, the write data from the I / F control unit 23 is R /
Since it is stored in the W data register 21, the data in this register is transferred to and stored in the EEPROM 25.

S14: If it is determined in the process of S12 that the reading is being performed, the read / write control unit 11
Read data (data read from the data head 9) is stored in the EEPROM 25.

In this case, since the read data from the read / write controller 11 is stored in the R / W data register 21, the data in this register is stored in the EEPROM.
25 to be stored.

S15: When the processes of S13 and S14 are completed, or when it is determined in the process of S12 that writing / reading is not in progress, control for stopping the rotation of the spindle motor 10 is performed. After that, the process returns to the process S3.

(Other Embodiments) Although the embodiments have been described above, the present invention can be implemented as follows. : The speed control unit provided in the motor control MPU is a PW.
Not limited to M control, any other control means may be used.

The spindle motor can be applied to a DC motor having any phase instead of three phases. : The non-volatile memory is not limited to the EEPROM, and another non-volatile memory may be used.

[0115]

As described above, the present invention has the following effects. : When the Hall element fails (is broken, etc.), the spindle motor can be rotated using the back electromotive force signal as rotation control information until the Hall element is replaced.

Therefore, the data write / read processing can be continuously performed, and the reliability of the magnetic disk device is improved. : Normally, by using a spindle motor (Hall motor) that uses the Hall element as a position detection sensor, it is possible to perform high-precision rotation control and sufficiently deal with failure of the Hall element.

When the back electromotive force is used as the rotation control information, no special position detecting sensor or the like is required. Therefore, without adversely affecting the mounting of the Hall element,
The back electromotive force signal can be taken out.

Since the combination of the Hall element output and the waveform of the back electromotive voltage signal is the same, the speed control section and the drive current phase switching section can be made common. Therefore,
The cost of the disk device can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a configuration diagram of a magnetic disk device.

FIG. 3 is an explanatory diagram of a hall element abnormality detection circuit.

FIG. 4 is an explanatory diagram of a counter electromotive voltage detection circuit.

FIG. 5 is a processing flowchart 1 of a motor control MPU.

FIG. 6 is a processing flowchart 2 of the motor control MPU.

FIG. 7 is an explanatory diagram of Conventional Example 1.

FIG. 8 is an explanatory diagram of Conventional Example 2.

[Explanation of symbols]

 2 spindle 3 magnetic disk (recording medium) 6 VCM (voice coil motor) 8 servo head 9 data head 10 spindle motor 11 read / write control unit 13 motor control MPU (microprocessor) 14 Hall element output detection circuit 15 motor drive circuit 16 Back Electromotive Voltage Detection Circuit 19 Selection Section 20 Motor Rotation Control Section 21 R / W (Read / Write) Data Register 22 Nonvolatile Memory 23 I / F (Interface) Control Section 24 Hall Element Abnormality Detection Circuit

Claims (4)

[Claims] 1. A spindle motor (10) for rotating a disk (3), and a motor control processor (13) for controlling the rotation of the spindle motor (10). The motor is provided with a hall element (HA) which is a position detecting sensor, and the motor control processor (13) controls the rotation of the spindle motor by using the output of the hall element (HA) as rotation control information. In a disk device, a counter electromotive voltage detection circuit (16) for detecting a counter electromotive voltage generated in the coil of the spindle motor (10).
Is connected to the motor control processor (13), if the hall element (HA) is normal, select the hall element output. If the hall element is abnormal, the counter electromotive voltage detection circuit (16) Selection unit (19) for selecting the counter electromotive voltage signal of
The disk device is characterized in that when the hall element is abnormal, the counter electromotive voltage signal is selected as the rotation control information instead of the hall element output to enable the rotation control of the spindle motor. 2. A Hall element (H
Hall element abnormality detection circuit (24) for detecting abnormality in A)
The hall element abnormality detection circuit (24) is equipped with a hall element (HA)
When the abnormality is detected, the motor control processor (13) is notified as an alarm signal (AL) so that the motor control processor (13) can recognize the normality / abnormality of the hall element (HA). The disk device according to claim 1, wherein 3. A non-volatile memory (2) accessible to a motor control processor (13) to the disk device.
2) is provided so that the Hall element (H
The disk device according to claim 1, wherein the motor control processor (13) stores the read / write data in the non-volatile memory (22) when A) becomes abnormal. 4. When the spindle motor (10) restarts after the rotation is stopped due to an abnormality in the Hall element and the counter electromotive voltage signal is restarted as rotation control information, the stored data in the nonvolatile memory (22) is read, 4. The disk device according to claim 3, wherein the work can be continued when the hall element abnormality occurs.