JPH06119707A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To start up the rotation of a sensorless spindle motor in a short time and to eliminate the occurrence of the reverse rotating state and yet to increase starting torque. CONSTITUTION:Motor phase changeover data are written in advance in a CSS zone of a magnetic disk 1, and at the time of starting up the rotation of the sensorless spindle motor 2, the motor phase changeover data Da-Df are read by an MR head 3. The sensorless spindle motor 2 is driven based on the motor phase changeover data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive for rotating a magnetic disk by a sensorless spindle motor.

[0002]

2. Description of the Related Art Magnetic disk devices are becoming more and more compact, and as a spindle motor for rotationally driving a magnetic disk, a sensorless motor in which a Hall element is removed from a conventional brushless DC direct drive motor having a Hall element is used. Is becoming more frequent. In such a sensorless motor, when the rotational speed reaches a certain level, the back electromotive force of the coil is detected, and a signal for switching the phase is obtained by delaying the detected signal.

However, the use of such a sensorless motor has the following problems.

First, since the back electromotive force of the motor coil is used as the phase switching signal, it cannot be used when the motor is stopped and at low speed. Therefore, conventionally, when the motor is stopped and at low speed, it is removed like a stepping motor. An open-loop type was used in which the phases were sequentially switched within a range that did not match. However, when switching phases by open loop based on a certain speed curve, it is necessary to set the speed curve on the assumption that the rising time is the longest so that step-out does not occur. In this case, if the rise time is fast, the rise time may be sacrificed, or the phase current may be reversed due to overshoot or undershoot when switching the phase current. It may disappear. In addition, since the position where the vehicle is stopped cannot be known when the vehicle is stopped, there is a drawback that the vehicle rotates in the reverse direction and then enters the normal rotation.

Secondly, when it becomes possible to detect the counter electromotive force at a certain rotational speed, the phase switching signal is obtained from the counter electromotive force to detect the rotational direction and rotational speed. Etc. external circuitry is required. Moreover, these circuits are required to be different from those for steady rotation. Therefore, there is a problem that the number of parts increases.

[0006]

SUMMARY OF THE INVENTION A first object of the present invention is to enable rotation start of a sensorless spindle motor in a short time, to prevent reverse rotation, and to increase starting torque. It is to provide a magnetic disk device capable of performing the above.

A second object of the present invention is to provide a magnetic disk device capable of detecting the rotation direction and the rotation speed without providing a special circuit for each phase of the sensorless spindle motor.

[0008]

In order to solve the above problems, a first invention is a magnetic disk having motor phase switching data written in a head standby zone, and a sensorless spindle motor for rotationally driving the magnetic disk. An MR head for reading data on a magnetic disk which is rotationally driven by the sensorless spindle motor, and motor phase switching data written in a head standby zone on the magnetic disk when the sensorless spindle motor is started to rotate. And a control means for controlling to sequentially supply drive power to each phase of the sensorless spindle motor based on the motor phase switching data.

According to a second aspect of the present invention, the head standby zone has a first surface on which an erase portion and a data portion having a predetermined length are written, and the head standby zone has an erase portion having a different length from the erase portion and the data portion. A magnetic disk having a second surface on which a data section is written; a sensorless spindle motor that rotationally drives the magnetic disk; a magnetic head that reads data on the magnetic disk that is rotationally driven by the sensorless spindle motor; When the magnetic head can read the data written in the head standby zone on the magnetic disk, the erase portion or the data portion of the first surface and the second surface are read in a predetermined order, and the erase portion is read. Alternatively, the determination of whether the sensorless spindle motor is forward or reverse is determined by the difference in the appearance order of the data section. ; And a stage.

[0010]

According to the first aspect of the present invention, the motor phase switching data is written in the head standby zone (hereinafter referred to as CSS zone) of the magnetic disk, and the motor phase switching data is stored when the rotation of the sensorless spindle motor is started. Since the sensorless spindle motor is driven based on the data read by the MR head and based on the motor phase switching data, the rotation of the sensorless spindle motor can be started in a short time, and no reverse rotation occurs.
Moreover, the starting torque can be increased. In the second invention, an erase part and a data part of a predetermined length are written in the CSS zone of the first surface of the magnetic disk, and the C of the second surface is written.
When the erase section and the data section having different lengths from the erase section and the data section are written in the SS zone and the data written in the CSS zone on the magnetic disk can be read by the magnetic head, the first surface The erase section or the data section of the second surface is read in a predetermined order, and the forward / reverse rotation of the sensorless spindle motor is determined by the difference in the appearance order of the erase section or the data section. It is possible to detect the rotation direction without providing a special circuit. The rotation speed can be detected based on the pattern on either surface.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a magnetic disk device according to the first embodiment of the present invention.

In the figure, 1 is a magnetic disk in which motor phase switching data is written in a CSS zone, 2 is a sensorless spindle motor for rotationally driving the magnetic disk 1, and 3 is a magnetic disk rotationally driven by a sensorless spindle motor 2. MR heads 4 for reading the data on 1 are head amplifiers for amplifying the signals read by the MR head 3. The MR head 3 is moved in the radial direction of the magnetic disk 1 by a head positioning mechanism (not shown).

Further, 5 is a first pulsing circuit for extracting a bit cell pulse from the signal amplified by the head amplifier, and 6 is a second pulsing circuit for extracting a bit cell pulse and a data pulse from the signal amplified by the head amplifier. The pulsing circuit 7 is a separation circuit for separating only the data pulse from the bit cell pulse and the data pulse.

Reference numeral 8 is a block / 1/0 judging circuit for judging the position of the block and 1/0 of the data pulse,
9 is a pattern determination circuit for determining a data pattern, 10
Is a motor drive circuit that sequentially supplies drive power to each phase of the sensorless spindle motor 2 based on the determined data.

Next, the motor phase switching data written in the CSS zone on the magnetic disk 1 will be described in detail.

Here, it is assumed that the sensorless spindle motor 2 is a bipolar three-phase motor having three coils 2a, 2b and 2c as shown in FIG. Then, the current patterns flowing through these coils 2a, 2b, 2c are the six types a to f shown in the figure. Therefore, as the motor drive circuit 10, three sets of switching circuits 10U, 10V and 10W shown in FIG. 3 are used.

The switching circuit 10U includes a pump P1.
The transistor Tr1 switches the U terminal to the Vcc voltage according to the switching signal A input via the transistor Tr2, and the transistor Tr2 switches the U terminal to the ground voltage according to the switching signal B input via the amplifier P2. The switching circuits 10V and 10W have the same configuration,
The V terminal and the W terminal are switched to the Vcc voltage or the ground voltage according to the switching signals C and D and the switching signals E and F, respectively. For example, when the current pattern a shown in FIG. 2 is used, the switching signal A and the switching signal D may be turned on.

Then, such a switching circuit 10
In order to drive the sensorless spindle motor 2 to rotate by U, 10V and 10W, for example, the switching signal A
4 to (F) may be switched at the timing shown in FIG. 4A, and the voltage waveforms of the U terminal, V terminal, and W terminal at that time are as shown in FIG. 4B.

Here, one electrical angle means a pair of angles of N pole and S pole of the rotor magnet of the motor. For example,
With a 2-pole motor, the electrical angle of 360 ° is the mechanical angle of 360
Corresponds to °. With an 8-pole motor, an electrical angle of 360 ° corresponds to a mechanical angle of 90 °. Therefore, for example, if the sensorless spindle motor 2 is a three-phase eight-pole motor, in order to rotate the magnetic disk 1 once, the sensorless spindle motor 2 is subjected to the six types of current patterns a to f shown in FIG. Just repeat. Therefore, in the present embodiment, one rotation of the CSS zone on the magnetic disk 1 is divided into 24 as shown in FIG. 5 in order to start the rotation of the sensorless spindle motor 2, and each zone is sequentially provided with 6 as motor phase switching data. 4 kinds of current pattern data Da to Df
I am writing a repeating pattern.

Next, a concrete example of the current pattern data Da to Df will be described.

In this embodiment, the current pattern data Da ...
One block of Df has a 4-bit configuration.

As the 4-bit data pattern, there are 14 kinds of 10000 8 1000 2 0001 9 1001 3 0010 A 1010 4 0011 B 1011 5 0100 C 1100 6 0101 D 1101 7 0111 F 1111. Of these, 0001, 1000 0010, 0100 0011, 1100 0101, 1010 0111, 1110 1011 and 1101 are left-right symmetrical patterns, respectively. However, if such left-right symmetrical patterns coexist as data patterns, if the sensorless spindle motor 2 rotates in the reverse direction at the start of rotation, it will be recognized as incorrect current pattern data. Therefore, in the present embodiment, such a left-right symmetrical pattern is not used as the current pattern data.

Further, such current pattern data Da
A read error may occur when reading ~ Df. For example, when there is a data pattern "0001",
When the first 1 bit is read-errored, it is recognized as a data pattern of "1001". Therefore, in the present embodiment, the data patterns of the adjacent current pattern data Da to Df each have a change of 2 bits or more so that the read error can be recognized. In addition, such current pattern data Da to Df appear repeatedly, and are therefore of the cyclic type.

From the above, in the case of the cyclic type adjacent data patterns each having a change of 2 bits, 0000 0011 1001 1111 0110 0101 0000 0011 1111 0110 0101 1001 0000 0101 0011 0110 1111 1001 0000 0101 0011 1001 1111 0110 0000 0101 0110 0011 1001 1111 0000 0101 0110 10 0011 1111 1001 0000 0101 01110 1111 0011 1001 0000 0101 0101 1011 1111 1001 0011 0000 0101 1001 0011 0110 0011 0101 0011 011 1111 0111 There is a 0000 0101 1001 1111 0110 0011 0000 0101 1111 0110 0011 1001 0000 0101 1111 1001 0011 0110. Since these patterns are cyclic, it does not matter where the starting point is.

Further, adjacent data patterns may each have a change of 3 bits. In that case, the pattern is 0000 0111 1001 0010 0101 1011 0000 1011 0101 0010 1001 0111 11 0010 1111 0001 0110 1011 0101 0010. 0101 1011 0110 0001 1111 is available.

Specific decoding is performed as follows, for example.

0000 is a pattern 1 0111 and 1110 is a pattern 2 1001 is a pattern 3 0010 and 0100 is a pattern 4 0101 and 1010 is a pattern 5 1011 and 1101 is a pattern 6, and each pattern 1 to 6 is current pattern data Da to Df. It is defined as For example, pattern 1 is defined as current pattern data Da pattern 2 as current pattern data Db pattern 3 as current pattern data Dc pattern 4 as current pattern data Dd pattern 5 as current pattern data De pattern 6 as current pattern data Df. Therefore, the switching signal A and the switching signal D are on in the pattern 1, the switching signal A and the switching signal F are on in the pattern 2, the switching signal C and the switching signal F are on in the pattern 3, and the switching signal B and the switching are on in the pattern 4. When the signal C is on, the switching signal B and the switching signal E are on when the pattern 5 is on. When the pattern 6 is on, the switching signal D and the switching signal E are turned on, and the switching circuits 10U, 10V, and 10W sequentially turn on each phase of the sensorless spindle motor 2. Driving power is supplied.

When a 4-phase motor is used, the following eight kinds of 4-bit data may be used, for example.

0000 0111 0010 1111 0001 0110 1011 1011 0110 0001 1111 0010 0111 0000 Next, a specific example of the signal of the motor phase switching data written in the CSS zone on the magnetic disk 1 will be described with reference to FIG. Here, the motor phase switching data is "1".
011 ".

As shown in FIG. 6A, a magnetization pattern for 2 + 1/2 tracks is written with respect to the head core width L. A magnetization pattern in which a bit data signal and a bit cell signal are superimposed is written in the first track T1, and a magnetization pattern of the bit cell signal is written in the second and third tracks T2 and T3. The pattern in which the bit cell signal continues twice represents a delimiter of data (block).

Therefore, the signal read by the MR head 3 has a low peak in the bit data signal portion and a high peak in the bit cell signal portion as shown in FIG. 6B.

Therefore, the first pulsing circuit 5 shown in FIG. 1 has the threshold level of V2 shown in FIG. 6 (c).
6d, the second pulsing circuit 6 extracts the bit cell pulse and the data pulse shown in FIG. 6 (d) at the threshold level of V1 lower than V2, and the separation circuit 7 makes the separation circuit 7 shown in FIG. 6 (d). By subtracting the pulse shown in FIG. 6C from the pulse shown in FIG.
The data pulse shown in (e) is obtained. Then, the block / 1/0 determination circuit 8 determines the position of the block and 1/0 of the data pulse. In this example, when there is one data pulse between bit cell pulses, it is defined as "1" and when there are two data pulses, "0".

Next, a description will be given of the operation of the magnetic disk device configured as described above when the disk is started.

When the disk is started, the MR head 3 is a CS in which the motor phase switching data on the magnetic disk 1 is written.
Standing by in S zone.

From this state, a minute current is passed through an arbitrary phase of the sensorless spindle motor 2. Then, the magnetic disk 1 slightly rotates, for example, about 0.1 mm or less.

By this minute rotation, the MR head 3 operates as a CSS.
Read the motor phase switching data written in the zone.

Then, based on the motor phase switching data, a current is passed from the motor drive circuit 10 to a predetermined phase of the sensorless spindle motor 2, and the magnetic disk 1 is rotated by the sensorless spindle motor 2.

After that, the MR head 3 sequentially reads the motor phase switching data written in the CSS zone, and based on the motor phase switching data, the motor drive circuit 10 sequentially supplies a current to a predetermined phase of the sensorless spindle motor 2. Then, the magnetic disk 1 is rotated by the sensorless spindle motor 2.

When the sensorless spindle motor 2 rises to a rotation speed that allows normal sensorless driving by the back electromotive force, the sensorless driving is switched to M.
The R head 3 is moved from the CSS zone to the target track, and then the normal access is performed.

As described above, in the magnetic disk apparatus of this embodiment, the motor phase switching data is written in the CSS zone of the magnetic disk 1 and the sensorless spindle motor 2 is used.
Since the motor phase switching data is read by the MR head 1 and the sensorless spindle motor 2 is driven based on this motor phase switching data at the time of starting the rotation of
The rotation of the sensorless spindle motor 2 can be started in a short time, the reverse rotation state does not occur, and the starting torque can be increased.

In the above-mentioned embodiment, the MR head 3 is used as the magnetic head because the MR head 3 can read the magnetization pattern from the disk without depending on the relative rotation speed of the head and the disk. This is because the polarity of the magnetization pattern does not change even if the rotation direction of is reversed. That is, in this embodiment, the MR head 3 needs to read the motor phase switching data written in the CSS zone by a minute rotation at the time of starting the rotation start-up as described above, and the disk may rotate in the reverse direction. Because.

Next, a second embodiment of the present invention will be described.

FIG. 7 is a block diagram showing the structure of a magnetic disk device according to the second embodiment. In the figure, 1
1 and 12 read / write signals to the magnetic disk
A magnetic head for writing, 13 and 14 are R / W amplifiers for amplifying read / write signals, and 15 is R
This is an AGC amplifier that amplifies the signals output from the / W amplifiers 13 and 14 to a constant value.

Further, 16 is a comparator for detecting a peak and outputting a pulse, 17 is a monostable composed of a digital circuit, 18 is a microprocessor for controlling the operation of the entire apparatus, 19 is a fixed gain operation for the AGC amplifier 15, or This is a switch for switching to AGC operation.

FIGS. 8A to 8D are views showing data patterns written in the CSS zone of the magnetic disk in this embodiment.

As shown in the figure, the data pattern is composed of an erase portion having a predetermined length and a data portion having a predetermined length. The frequency of the data section is the highest frequency of the writing frequency of the magnetic disk device. Here, in the magnetic disk device, the magnetic disk is 3000R.
Assuming that the data is rotated at PM, the data pattern HD0 of the magnetic disk on the magnetic head 11 side has 60 pairs of erase parts and data parts per rotation, and one set of erase parts and data parts when rotating at 3000 RPM. 333.
It has a length of 3 μs. Also, the magnetic head 1
The data pattern HD1 of the magnetic disk on the second side has 300 combinations of erase part and data part per revolution,
When rotating at 0 RPM, one set of the erase section and the data section has a length of 6666.6 μs. Further, the end point of the data section in HD0 is set to be the start point of the data section in HD1. Therefore, the monostable 17 outputs pulses as shown in FIGS. 8E and 8F, respectively.

Next, the operation of the magnetic disk device configured as described above will be described with reference to the flow chart shown in FIG.

First, the switch 19 is switched so that the AGC amplifier 15 operates in a fixed gain (step 90).
1).

Next, the rotation of a sensorless spindle motor (not shown) is started (step 902).

When it starts to rotate to some extent, HD0
Is selected (step 902), the erase portion is detected (step 903), and the data portion is detected (step 90).
4), HD1 is selected (step 905).

At this time, if the erase portion cannot be detected (step 906), it is determined that the sensorless spindle motor is rotating in the reverse direction (step 907).

On the other hand, if the erase portion is detected (step 906), the process waits until the data portion is detected (step 908), and when the data portion is detected, HD0 is selected (step 909).

At this time, if the erase portion cannot be detected (step 910), it is determined that the sensorless spindle motor is rotating in the reverse direction (step 907).

On the other hand, if the erase portion is detected (step 910), the process waits until the data portion is detected (step 911). When the data portion is detected, HD1 is selected (step 912).

At this time, if the data portion cannot be detected (step 913), it is determined that the sensorless spindle motor is rotating in the reverse direction (step 907).

On the other hand, if the data portion is detected (step 913), it is determined that the sensorless spindle motor is rotating normally, and further acceleration is performed to control the rotation so that it is in steady rotation (step 914).

When it is determined that the sensorless spindle motor is rotating in the reverse direction (step 907), the rotation of the sensorless spindle motor is restarted again (step 902).

As described above, in the magnetic disk device of this embodiment, the erase part and the data part having a predetermined length are written in the CSS zone on the first surface of the magnetic disk, and the erase part and the data part are written in the CSS zone on the second surface. Write an erase part and a data part of different lengths from the
When the data written in the S zone can be read by the magnetic head, the erase part or the data part of the first surface and the second surface are read in a predetermined order, and the appearance order of the erase part or the data part is different. Since the normal rotation / reverse rotation of the sensorless spindle motor is determined, the rotation direction can be detected without providing a special circuit for each phase of the sensorless spindle motor. The rotation speed can be detected based on the pattern on either surface.

[0060]

As described above, according to the present invention, the rotation of the sensorless spindle motor can be started in a short time, and the reverse rotation state does not occur.
Moreover, the starting torque can be increased.

Further, the rotation direction and the rotation speed can be detected without providing a special circuit for each phase of the sensorless spindle motor.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a magnetic disk device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a sensorless spindle motor shown in FIG.

FIG. 3 is a diagram showing a configuration of a motor drive circuit shown in FIG.

FIG. 4 is a waveform diagram showing drive timing of the sensorless spindle motor shown in FIG.

5 is a diagram showing current pattern data written in a CSS zone on the magnetic disk shown in FIG. 1. FIG.

FIG. 6 is a diagram showing a specific example of a signal of motor phase switching data.

FIG. 7 is a block diagram showing a configuration of a magnetic disk device according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a data pattern written in a CSS zone of a magnetic disk in the second embodiment.

FIG. 9 is a flowchart showing an operation of the magnetic disk device according to the second embodiment.

[Explanation of symbols] 1 ... Magnetic disk, 2 ... Sensorless spindle motor,
3 ... MR head, 4 ... Head amplifier, 5 ... First pulsing circuit, 6 ... Second pulsing circuit, 7 ... Separation circuit, 8 ...
Block / 1/0 decision circuit, 9 ... Pattern decision circuit, 1
0 ... Motor drive circuit.

Claims (2)

[Claims] 1. A magnetic disk in which motor phase switching data is written in a head standby zone, a sensorless spindle motor for rotationally driving the magnetic disk, and data on the magnetic disk rotationally driven by the sensorless spindle motor is read. When the rotation of the MR head and the sensorless spindle motor is started,
Control for reading motor phase switching data written in the head standby zone on the magnetic disk by the MR head, and controlling so as to sequentially supply drive power to each phase of the sensorless spindle motor based on the motor phase switching data. And a magnetic disk device. 2. A first surface on which an erase portion and a data portion having a predetermined length are written in the head standby zone, and an erase portion and a data portion having different lengths from the erase portion and the data portion are written in the head standby zone. A magnetic disk having a second surface formed on the magnetic disk, a sensorless spindle motor that rotationally drives the magnetic disk, a magnetic head that reads data on the magnetic disk that is rotationally driven by the sensorless spindle motor, and a magnetic disk on the magnetic disk. When the data written in the head standby zone can be read by the magnetic head, the erase part or the data part of the first surface and the second surface are read in a predetermined order, and the erase part or the data part of the erase part is read. Determination means for determining forward / reverse rotation of the sensorless spindle motor based on a difference in appearance order A magnetic disk device characterized in that.