JP3019697B2 - Spindle motor drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus for recording information on a recording layer of an optical disk and reproducing / erasing previously recorded information by using a light spot obtained by focusing the light of a semiconductor laser with a lens. And a spindle motor driving device.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a conventional spindle motor driving device. A conventional technique will be described with reference to FIG.

[0003] In FIG.
2 is an optical head, 103 is a clock extraction circuit, 104 is an error signal generation circuit, 105 is a low-pass filter, 106 is a drive circuit, and 107 is a spindle motor.

In the spindle motor driving device constructed as described above, when the light spot follows a predetermined track of the optical disk 101 and records information on the recording layer of the optical disk 101 or reproduces / erases information recorded in advance. Will be described.

In the case of a compact disk or a read-only mini disk, the number of rotations of the optical disk 101 is controlled so that the linear velocity becomes constant with respect to the irradiation position of the light spot.
The optical head 102 reads an EFM signal from pits formed on a recording layer of the optical disc 101.

Then, a clock extracting circuit 103 extracts a frame synchronizing signal of the EFM signal from the EFM signal reproduced by the optical head 102. The extracted frame synchronization signal is input to the error signal generation circuit 104. On the other hand, a reference clock signal having the reference frequency of the frame synchronization signal is input from the system controller 108 to the error signal generation circuit 104. The error signal generation circuit 104 detects a phase difference or a frequency difference between a reference clock signal having a reference frequency of the frame synchronization signal and the extracted frame synchronization signal, and generates and outputs a servo error signal.

[0007] The servo error signal generated by the error signal generating circuit 104 is smoothed by a low-pass filter 105,
6 is rotated at a predetermined rotation speed.

When the optical head 102 accesses the target position during the reproduction of information, the clock extraction circuit 10
3, the frame synchronization signal cannot be extracted. for that reason,
The error signal generation circuit 104 first binarizes the reproduction signal from the optical head 102 and detects the longest period of the binarized reproduction signal. At this time, the system controller 108 outputs a reference clock signal of a predetermined cycle to the error signal generation circuit 104.

The error signal generating circuit 104 generates a servo error signal such that the detected longest cycle becomes a predetermined reference cycle.

On the other hand, in an optical disk such as a rewritable mini disk, a track on the optical disk 101 has a guide groove which is wobbled.

Next, the operation of the spindle motor driving device when following a predetermined track of the optical disk 101 will be described.

First, the optical head 102 reads a tracking error signal. Then, the clock extraction circuit 103 binarizes the wobble signal included in the read tracking error signal and generates predetermined address data from the binarized wobble signal. The clock extraction circuit extracts a predetermined clock signal from the generated address data. At this time, the system controller 108 outputs a clock signal of a predetermined cycle to the error signal generation circuit 104.
The error signal generation circuit 104 detects a phase difference or a frequency difference between the extracted clock signal and a reference clock signal having a reference frequency of the clock signal, and generates a servo error signal.

When the optical head 102 accesses the target position, a wobble signal is superimposed on the track cross signal in the tracking error signal read from the optical head 102. Therefore, the clock signal extraction circuit 1
No. 03 cannot extract a predetermined clock signal.
Then, the error signal generation circuit 104 cannot generate a servo error signal by the extracted clock signal, and the error signal generation circuit 104 outputs a reference level of the servo error signal,
The spindle motor 107 is driven by inertia.

[0014]

However, in the conventional spindle motor driving apparatus, when recording information on a rewritable mini-disc or reproducing / erasing information recorded in advance, an optical head accesses a target position. At that time, the error signal generation circuit could not generate the servo error signal.

Therefore, the error signal generating circuit outputs the reference level of the servo error signal to drive the spindle motor by inertia, and it takes time to pull the spindle servo to the predetermined rotation speed at the target position immediately after the access. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and shortens the pull-in time of a spindle motor to a predetermined number of revolutions immediately after the end of access to a target position on a rewritable optical disk, thereby achieving high-speed access. It is an object of the present invention to provide a spindle motor driving device that enables the spindle motor driving.

[0017]

In order to achieve the above object, a spindle motor driving apparatus according to the present invention comprises a clock extracting means for extracting a clock signal having a predetermined frequency from a reproduction signal from an optical head, and the clock extracting means. Error signal generating means for detecting a frequency difference or a phase difference between a clock signal extracted by the above and a reference clock signal to generate a servo error signal of the spindle motor, and the spindle motor according to an output level of the error signal generating means Drive means for supplying a drive current to the optical head, level selecting means for selecting a predetermined level according to an address value of the target position when accessing the optical head, and causing the optical head to access the target position. During this time, the input signal to the driving means is switched from the output of the error signal generating means to the output of the level selecting means. And a switching means that.

Further, according to the present invention, the holding means for holding the output of the error signal generating means immediately before the optical head accesses the target position, and calculates the difference between the address value immediately before the start of the access and the address value of the target position. Calculating means, an error increment predicting means for predicting a level increment of the error signal generating means at a target position by an output of the calculating means, and adding an output of the previous value holding means and an output of the error increment predicting means. Adding means for setting a predetermined level of the level selecting means.

The present invention also provides a clock extracting means for extracting a clock signal having a predetermined frequency from a reproduced signal from an optical head, and a frequency difference or a position between the clock signal extracted by the clock extracting means and a reference clock signal. An error signal generating means for detecting a phase difference to generate a servo error signal of the spindle motor; a driving means for supplying a drive current to the spindle motor according to an output level of the error signal generating means; Calculating means for calculating an address difference between an address value immediately before the start of access and an address value of a target position when accessing a position; and driving pulse generating means for generating a driving pulse having a predetermined width in accordance with an output of the calculating means Addition means for adding the output of the drive pulse generation means and a predetermined level; and positioning the optical head at a target position. While to Seth and a switching means for switching the output of said adding means an input signal to the drive means from an output of said error signal generating means.

[0020]

According to the present invention, a light signal follows a predetermined track on an optical disk and a clock signal of a predetermined frequency is reproduced from a reproduction signal from an optical head when recording, reproducing and erasing information. It is extracted by clock extraction means. The error signal generator detects a frequency difference or a phase difference between the clock signal extracted by the clock extractor and the reference clock signal, and generates a servo error signal of the spindle motor. When the optical head accesses the target position, the level selecting means selects the output level of the error signal generating means near the target position according to the address value of the target position. While the optical head is accessing the target position, the input to the driving means is switched from the output of the error signal generating means to the selected level selected by the level selecting means to drive the spindle motor.

According to the present invention, the holding means holds the output level of the error signal generating means immediately before the optical head accesses the target position. The calculating means calculates an address difference between the address value of the access start position and the address position of the target position. The error increment predicting means predicts and outputs the increment level between the output of the error signal generating means at the access start position and the output of the error signal generating means at the target position based on the output of the calculating means. Then, the adding means adds the output of the holding means and the output of the error increment predicting means, and sets the output of the adding means as the selection level of the level selecting means.

Further, according to the present invention, when the light spot follows a predetermined track on the optical disk and the recording, reproduction and erasure of information is performed, a clock signal having a predetermined frequency is obtained from a reproduction signal from the optical head. The signal is extracted by the clock extracting means. The error signal generator detects a frequency difference or a phase difference between the clock signal extracted by the clock extractor and the reference clock signal, and generates a servo error signal of the spindle motor. When the optical head accesses the target position, the calculation means calculates a difference between the address value of the access start position and the address value of the target position.
The pulse generation means generates a drive pulse having a predetermined width according to the output of the calculation means. The adding means adds the pulse generated by the pulse generating means and a predetermined level. While the optical head is being accessed to the target position, the switching means switches the input to the driving means from the output of the error signal generating means to the output of the adding means to drive the spindle motor.

[0023]

Embodiments of the present invention will be described below.

FIG. 1 is a block diagram showing a configuration of a spindle motor driving device according to a first embodiment of the present invention.
Here, a description will be given focusing on newly added components in the conventional configuration shown in FIG.

In FIG. 1, 1, 2, 4, 5, 6, and 7 are analog switches, 3 is an inverter, and 8, 9, 10, 1
1 is a voltage source and 108a is a system controller.

The spindle motor driving apparatus according to the first embodiment having the above-described structure will be described with reference to FIG. 2 showing the relationship between the reproduction radial position and the rotation speed of the optical disk 101.

When the light spot follows a predetermined track of the optical disc 101 and records information on the recording layer of the optical disc 101 or reproduces / erases information recorded in advance, the error signal is generated by the error signal generating circuit 104. The spindle motor 107 is driven by the servo error signal. At that time, the spindle motor 107 rotates the optical disc 101 by a predetermined amount so that the linear velocity at the irradiation position of the light spot on the optical disc 101 becomes a constant value. FIG. 2 shows the reproduction radius position on the optical disk 101 and the optical disk 101.
The radius position of the optical disc 101 can correspond substantially to the address value on the optical disc 101.

The voltage source 8 of FIG. 1 generates a voltage level Vref1 substantially equal to the smoothed level of the servo error signal at the radial position R1 by the low-pass filter 105, and the voltage source 9 generates a low-pass filter of the servo error signal at the radial position R2. 10
5 generates a voltage level Vref2 substantially equal to the smoothing level. Further, voltage sources 10 and 11 for generating the same voltage level as the smoothing level of the low-pass filter 105 at the reproduction radius position R3 and an arbitrary reproduction radius position Rn are provided.

The signals adr1, adr2, adr3, and adrn from the system controller 108a are voltage level selection signals, and all hold "LOW" when the light spot follows a predetermined track.

When causing the optical head 102 to access the target position, the system controller 108a first sets the voltage level selection signals adr1, a corresponding to the target position.
"HIGH" for any of dr2, adr3 and adrn
Is output. For example, if the target position is the position of address 1 of the reproduction radius position R1, the system controller 108a
Outputs "HIGH" only to the voltage level selection signal adr1. Then, the analog switch 4 is turned "ON" to select the voltage level Vref1 of the voltage source 8. And
At the same time that the optical head 102 starts accessing the target position, the system controller 108a outputs “HIGH” to the access start signal “access”. Then, the access start signal holds “HIGH” until the access to the target position is completed. While the access start signal “access” is “HIGH”, the analog switch 1 is in the “ON” state, and the analog switch 2 is in the “OFF” state. Then, the voltage level Vref1 of the voltage source 8 is input to the drive circuit 106, and the optical disk 101 is rotated at the rotation speed N1 at the reproduction radial position R1.

Thus, while the optical head 102 accesses the target position, the rotation speed of the optical disk 101 can be set to a predetermined rotation speed at the target position in advance, and the pull-in time of the spindle servo immediately after the access is completed can be shortened. , High-speed access can be realized.

Next, a second embodiment of the present invention will be described. FIG. 3 is a block diagram showing a configuration of a spindle motor driving device according to a second embodiment of the present invention. Here, the description will focus on the components that are different from the first embodiment.

In FIG. 3, reference numeral 12 denotes a hold circuit;
Is an arithmetic circuit, 14 is an error increment prediction circuit, 15 is an adder,
108b is a system controller.

These operations will be described with reference to FIG. FIG. 4 shows the relationship between the reproduction radius position on the optical disk 101 and the rotation speed of the optical disk 101.

Here, the operation when the access start position of the optical head 102 is address 3 and the target position is address 1 will be described.

First, when the optical head 102 accesses the target position, the output level of the low-pass filter 105 at address 3 immediately before the start of access is held by the hold circuit 12.
Hold by

The holding of the output level of the low-pass filter 105 is controlled by the signal "HOLDSTRT". The signal “HOLDSTRT” outputs “HIGH” immediately before the start of access until the access is completed. During this time, the hold circuit 12 holds and outputs the output level of the low-pass filter 105. Immediately before the start of access, the system controller 108b sends the address value of the address 3 which is the access start position to the signal “STRTad”.
r ", the address value of address 1 which is the target position is signal"
ENDadr "is output to the arithmetic circuit 13.

The operation circuit 13 outputs the signal "STRTadr".
Then, the value of the address input by the signal “ENDadr” is subtracted to calculate the increment △ adr of the moving address.
The calculated movement address increment △ adr is input to the error increment prediction circuit 14, and the error increment prediction circuit 14 determines whether the low-pass filter 105 at the address 3 which is the access start position.
And the incremental level of the output of the low-pass filter 105 at the address 1 which is the target position is predicted and output. Then, the adder 15 adds the output of the low-pass filter 105 at the address 3 held by the hold circuit 12 and the increment level output from the error increment prediction circuit 14.

The system controller 108b outputs "HIGH" to the signal "access" simultaneously with the start of the access, and holds "HIGH" until the end of the access.

Then, the signal "access" becomes "HIG".
H, the analog switch 1 is set to “O”.
N "state, and the analog switch 2 becomes" OFF "state.

At this time, the output of the addition circuit 15 is input to the drive circuit 106, and the optical head 102 is moved to the reproduction radius position R1.
, The optical disk 101 is rotated in advance at the rotational speed N1 at the reproduction radial position R1.

Thus, the rotation speed of the optical disk 101 can be set to the predetermined rotation speed at the target position in advance while the optical head 102 accesses the target position, and the pull-in time of the spindle servo immediately after the access is completed can be shortened. , High-speed access can be realized.

Next, a third embodiment of the present invention will be described. FIG. 5 is a block diagram showing a configuration of a spindle motor driving device according to a third embodiment of the present invention. Here, the description will focus on the components that are different from the second embodiment.

In FIG. 5, 16 is a drive pulse generation circuit, 17 is a voltage source, and 108c is a system controller.

Next, these operations will be described. First, the arithmetic circuit 13 calculates the difference between the address value of the access start position and the address value of the target position as Δa, as in the second embodiment.
Output as dr.

The drive pulse generation circuit 16 is provided with an arithmetic circuit 13
Generates a drive pulse having a predetermined width in accordance with the signal "@adr" output by the. Then, the adder 15 adds the drive pulse having a predetermined width generated by the drive pulse generation circuit 16 and the voltage level Vref of the voltage source 17.
At this time, the voltage level Vref of the voltage source 17 is set to the reference level of the error signal generation circuit 104.

During the access, the system controller 108c changes the signal “access” to “HIG”.
H "is output, and the analog switch 1 is turned" ON "and the analog switch 2 is turned" OFF ".

At this time, the input of the driving circuit 106 is switched from the output of the low-pass filter 105 to the output of the adder 15. Then, the spindle motor 106 is accelerated or decelerated by the output pulse of the drive pulse generation circuit 16, is thereafter inertia-driven, and completes the access in a state where the rotational speed substantially coincides with the predetermined number of revolutions at the target position.

Thus, the rotation speed of the optical disc 101 can be made to substantially match the rotation speed of the optical disk 101 in advance at the target position during the access, the pull-in time of the spindle servo immediately after the access is completed can be shortened, and high-speed access can be realized.

[0050]

As described above, according to the present invention, the pull-in time of the spindle servo immediately after the end of access can be shortened, and high-speed access can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a spindle motor driving device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a reproduction radial position on the optical disc and a rotation speed of the optical disc in the first embodiment.

FIG. 3 is a block diagram showing a configuration of a spindle motor driving device according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a relationship between a reproduction radial position on an optical disc and a rotation speed of the optical disc in the second embodiment.

FIG. 5 is a block diagram illustrating a configuration of a spindle motor driving device according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional spindle motor driving device.

[Explanation of symbols]

 1, 2, 4 to 7 Analog switch 3 Inverter 8 to 11, 17 Voltage source 12 Hold circuit 13 Operation circuit 14 Error increment prediction circuit 15 Adder 16 Pulse generation circuit 108a, 108b, 108c System controller

Claims (1)

(57) [Claims] 1. A spindle motor for rotating an optical disk at a predetermined rotation speed, an optical head for detecting a reflected light from the optical disk to obtain a reproduction signal, and a clock signal having a predetermined frequency from the reproduction signal from the optical head Clock extracting means for extracting a clock signal extracted by the clock extracting means and a frequency difference or a phase difference between a reference clock signal and an error signal generating means for generating a servo error signal of the spindle motor; Driving means for supplying a driving current to the spindle motor in accordance with an output level of the error signal generating means; and driving the optical head in accordance with an address value of the target position when accessing the target position.
Level selecting means for applying a dynamic voltage to the spindle motor
Before the step and allowing the optical head to access the target position
The input signal to the driving means is output from the error signal generating means.
Switching means for switching from the output to the output of the level selecting means
And the level selecting means moves the optical head to a target position.
The output of the error signal generating means immediately before accessing the device.
Hold means to hold and the address value immediately before access
Calculating means for calculating a difference between the address value of the target position and the address value of the target position;
Generating an error signal at a target position by the output of the calculating means
Error increment prediction means for predicting a level increment of the means,
The output of the hold means and the output of the error increment prediction means
Characterized by comprising adding means for adding.
Motor drive device.