JPH11136985A - Pulse width modulation signal, generator, motor controller and optical disc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a pulse width modulation signal through simple circuitry. SOLUTION: This pulse width modulation signal generator includes a control means 13 comprising a microprocessor incorporating a timer 133 and having a single bit output terminal, i.e., an I/O port 134, delivering a pulse width modulation signal(PWM signal). Duration of Low and Hi signals being delivered from the I/O port 134 is set by the timer 133. A pulse width modulation signal delivered from the I/O port 134 is smoothed through a smoothing filter 12 and converted into a voltage having magnitude corresponding to the pulse width in order to control the r.p.m. of a spindle motor 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse width modulation signal generator, a motor controller, and an optical disk drive.

[0002]

2. Description of the Related Art An optical disk device for recording and / or reproducing an optical disk (for example, a CD-ROM drive device, a CD-R drive device, a CD-WR drive device).
It has been known.

[0003] This optical disk device is provided with a motor (spindle motor) for rotating and driving the optical disk during recording and reproduction of the optical disk. This motor drives while its rotation speed (rotation speed) is controlled.

[0004] The rotation speed control of the motor is performed based on a WOBBLE PWM signal output from a WOBBLE servo controller when, for example, an unrecorded optical disk is rotated. This PWM signal is a pulse width modulation signal.

Some microprocessors (microcomputers) do not have a function of outputting the PWM signal. In this case, a dedicated IC having the function of outputting the PWM signal must be separately provided. I didn't. For this reason, there is a drawback that the configuration of the apparatus is complicated and the cost is increased.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pulse width modulation signal generating apparatus capable of outputting a pulse width modulation signal with a simple configuration, a motor control apparatus including the same,
An optical disk device is provided.

[0007]

This and other objects are achieved by the present invention which is defined below as (1) to (6).

(1) It has a timer function and
A microprocessor having a bit output terminal,
A pulse width modulation signal generating device that outputs a pulse width modulation signal from the output terminal, wherein a duty ratio of the pulse width modulation signal is changed by changing a set time of the timer. And a pulse width modulation signal generation device.

(2) It has a timer function and
A microprocessor having a bit output terminal,
A pulse width modulation signal generating device for outputting a pulse width modulation signal from the output terminal, wherein a period of a Low signal and a Hi signal output from the output terminal is set by the timer, respectively. Signal generator.

(3) While having a timer function,
A microprocessor having a bit output terminal,
A pulse width modulation signal generating device that outputs a pulse width modulation signal from the output terminal; and a smoothing circuit that smoothes and outputs the pulse width modulation signal, and a motor rotation speed based on an output value from the smoothing circuit. A motor control device configured to change a duty ratio of the pulse width modulation signal by changing a set time of the timer.

(4) While having a timer function,
A microprocessor having a bit output terminal,
A pulse width modulation signal generating device that outputs a pulse width modulation signal from the output terminal; and a smoothing circuit that smoothes and outputs the pulse width modulation signal, and a motor rotation speed based on an output value from the smoothing circuit. A period of the Low signal and the period of the Hi signal output from the output terminal, respectively, set by the timer.

(5) An optical disk device for recording and / or reproducing an optical disk, comprising: a motor for rotating and driving the optical disk; and the motor control device according to (3) or (4). Optical disk device.

(6) An optical disk apparatus for recording and / or reproducing an optical disk, comprising: a motor for driving the optical disk to rotate; a motor rotation speed detecting means for detecting the rotation speed of the motor; ), And changes the set time of the timer in the motor control device according to the motor rotation speed detected by the motor rotation speed detection means, and adjusts the voltage applied to the motor. An optical disk device for controlling the number of rotations of the motor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a pulse width modulation signal generating device, a motor control device and an optical disk device according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a block diagram showing a state in which the optical disk device of the present invention is connected to a computer, and FIG. 2 is a block diagram showing an embodiment of the optical disk device of the present invention.

The optical disk device 1 shown in these figures is a CD-R drive device for recording and reproducing an optical disk (CD-R) 2.

A spiral pre-groove (WOBBLE: not shown) is formed on the optical disk 2.

The pre-groove meanders at a predetermined period (22.05 kHz at 1 × speed), and the pre-groove has an ATIP (Absolute Time In Pre-Groove).
) Information (time information) is recorded. In this case, A
The TIP information is bi-phase modulated.
It is FM-modulated and recorded at a carrier frequency of 05 kHz.

The pregroove functions as a guide groove when forming pits / lands on the optical disk 2 (pit / land recording). Also, this pre-groove is played,
It is used for controlling the rotation speed of the optical disc 2 and for specifying the recording position (absolute time) on the optical disc 2.

The optical disk device 1 includes a turntable and a spindle motor 8 for rotating the turntable (for rotating the optical disk), and has a rotation drive mechanism (not shown) for mounting and rotating the optical disk 2 on the turntable. A Hall element 9 is installed near the spindle motor 8 as a sensor for detecting the rotation of the spindle motor 8. The FG signal (sine wave) is output from the Hall element 9 with the rotation of the spindle motor 8. The period of the FG signal corresponds to the rotation speed of the spindle motor 8.

The optical disk device 1 has an optical head (optical pickup) 3 that can move in the radial direction of the optical disk 2 (radial direction of the turntable) with respect to the loaded optical disk 2 (turntable). An optical head main body moving mechanism (not shown) including a sled motor 5 for moving the head 3 in the radial direction, that is, an optical head main body (optical pickup base) of the optical head 3 described later in the radial direction, and drivers 6 and 11 And PWM
Signal smoothing filters (smoothing circuits) 7 and 12, control means 13, laser control unit 14, HF signal generation circuit 15, HF signal gain switching circuit 16,
Bottom detection circuit 17, error signal generation circuit 18, W
OBBLE signal detection circuit 19, CD servo controller 21, WOBBLE servo controller 22, F
A G signal binarization circuit 23, an EFM / CDROM encoder control unit 24, memories 25, 26 and 29, a sync signal generation / ATIP decoder 27, a CDROM decoder control unit 28, an interface control unit 31,
It has clocks 32, 33, 34 and 35 and a casing 10 for accommodating them. Hereinafter, the radial direction of the optical disk 2 is simply referred to as “radial direction”.

The optical head 3 includes an optical head body (optical pickup base) (not shown) provided with a laser diode (light source) and a split photodiode (light receiving element).
An objective lens (condensing lens). The driving of the laser diode is controlled by the laser controller 14.

The objective lens is supported by a suspension spring (not shown) provided on the optical head main body, and can move in the radial direction and the rotation axis direction of the optical disk 2 (turntable) with respect to the optical head main body. ing. When the objective lens deviates from its neutral position (middle point), the objective lens is urged toward the neutral position by the restoring force of the suspension spring. Hereinafter, the direction of the rotation axis of the optical disc 2 will be simply referred to as “the direction of the rotation axis”.

The optical head 3 has an actuator 4 for moving the objective lens in the radial direction and the rotation axis direction with respect to the optical head body.

The control means 13 comprises a microprocessor (microcomputer: CPU), and comprises an optical head 3 (actuator 4), a sled motor 5, a spindle motor 8, a laser control unit 14, an HF signal gain switching circuit 16, Bottom detection circuit 17, CD servo controller 21, WOBBLE servo controller 2
2. It controls the entire optical disc device 1 such as the EFM / CDROM encoder control unit 24, the memories 25, 26, and 29, the sync signal generation / ATIP decoder 27, the CDROM decoder control unit 28, and the interface control unit 31.

The address, data, and COMMAN are sent from the control means 13 via the address / data bus 36.
D (command) and the like are input to the EFM / CDROM encoder control unit 24, the memory 26, the sync signal generation / ATIP decoder 27, the CDROM decoder control unit 28, the interface control unit 31, and the like.

An external device (computer 41 in this embodiment) is detachably connected to the optical disk device 1 via an interface control section 31 so that communication between the optical disk device 1 and the computer 41 can be performed. it can.

The interface control unit 31 includes, for example, ATAPI (IDE) (Attape standard), SC
SI (squay standard) or the like is used.

The computer 41 has a keyboard 4
2. The mouse 43 and the monitor 44 are connected respectively.

The transmission means is constituted by the interface control section 31. HF signal generation circuit 1
5, HF signal gain switching circuit 16, peak / bottom detection circuit 17, error signal generation circuit 18, WOBBLE
The signal detection circuit 19, the CD servo controller 21 and the WOBBLE servo controller 22 constitute a signal processing unit.

Next, the operation of the optical disk device 1 will be described. The optical disc device 1 records (writes) and reproduces (reads) information (data) on the optical disc 2 while performing focus control, tracking control, thread control, and rotation speed control (rotation speed control) on a predetermined track. I do. Hereinafter, recording, reproduction, focus control, tracking control and thread control,
The operation at the time of rotation speed control (rotation speed control) will be described.

First, as a premise, as shown in FIG. 2, a predetermined COMMAND signal is input from the control means 13 to the CD servo controller 21. Control means 1
From 3, a predetermined COMMAND signal is input to the WOBBLE servo controller 22.

This COMMAND signal is supplied to the control means 13
Is a signal indicating a predetermined command (for example, start of control, etc.) to the CD servo controller 21 or the WOBBLE servo controller 22 from the controller.

Then, a predetermined STATUS signal is input to the control means 13 from the CD servo controller 21. Further, a predetermined STATUS signal is input from the WOBBLE servo controller 22 to the control means 13.

The STATUS signal is a signal indicating a response to the command, ie, information on the control (for example, statuses such as control success, control failure, and control being executed).

[Recording] Recording (writing) data (signal) on the optical disk 2
At this time, the pre-groove formed on the optical disc 2 is reproduced (read), and thereafter, data is recorded along the pre-groove.

When data (signal) to be recorded on the optical disk 2 is input to the optical disk device 1 via the interface control unit 31, the data is transmitted to the EFM / CRO.
It is input to the M encoder control unit 24.

In the EFM / CDROM encoder control section 24, the data is encoded (at the timing of the clock signal) based on the clock signal from the clock 34, and is modulated by a modulation method called EFM (Eight to Fourteen Modulation). EFM modulation) and ENC
This is an ORDE EFM signal.

As shown in FIG. 3, this ENCODE
The EFM signal is a signal composed of pulses having a length (period) of 3T to 11T.

As shown in FIG. 4 and FIG.
In the M / CDROM encoder control unit 24, the clock 3
4 is divided to generate a SUBCODE-SYNC signal (subcode sync signal) composed of pulses of a predetermined cycle. This SUBCODE-SY
Cycle of NC signal pulse (interval between adjacent pulses)
Is 1/75 second at 1 × speed.

At the time of the encoding, a synchronization signal, that is, a SYNC pattern (sync pattern) is transmitted to the SU.
Based on the BCODE-SYNC signal (SUBCODE
-At the timing of the SYNC signal), the ENCODE
It is added to the EFM signal. That is, SYNC is added to the portion corresponding to the head of each subcode frame.
A pattern is added.

This ENCODE EFM signal corresponds to EF
The data is input from the M / CDROM encoder control unit 24 to the laser control unit 14.

Also, WRITE P which is an analog signal
An OWER signal (voltage) is output from a D / A converter (not shown) built in
Is input to

The laser control section 14 has an ENCODE E
On the basis of the FM signal, the WRITE
The level of the POWER signal is switched between a high level (H) and a low level (L) and output, whereby the driving of the laser diode of the optical head 3 is controlled.

More specifically, the laser control unit 14
While the level of the ORDE EFM signal is high (H), the level of the WRITE POWER signal is set to high (H) and output. That is, the output of the laser is increased (write output). And ENCODE
While the level of the EFM signal is low (L), the WRI
The level of the TE POWER signal is set to a low level (L) and output. That is, the output of the laser is reduced (return to read output).

As a result, the optical disc 2 has an ENCO
When the level of the RDE EFM signal is high (H), a pit of a predetermined length is written, and ENCODE EFM is written.
When the level of the FM signal is low (L), a land of a predetermined length is written.

In this manner, data is written (recorded) on a predetermined track of the optical disc 2.

EFM / CDROM encoder control unit 24
In this case, a predetermined ENCODE EFM signal (random EFM signal) is generated in addition to the above-mentioned ENCODE EFM signal. This random EFM signal is output from the OPC (Op
timum Power Control), laser output adjustment (power control) when test writing to test area
Used for

At the time of test writing in the test area in the OPC, the random EFM signal is generated by the EFM / CRO
The data is input from the M encoder control unit 24 to the laser control unit 14.

At the time of test writing in the test area in the OPC, the control means 13 generates a WRITE POWER signal of 15 levels and outputs the WRITE POWER signal.
The EPOWER signal is output from a D / A converter (not shown) built in the control unit 13 and input to the laser control unit 14.

Then, the laser control unit 14 receives the WRIT from the control unit 13 based on the random EFM signal.
The level of the E POWER signal is switched between a high level (H) and a low level (L) and output, thereby controlling the driving of the laser diode of the optical head 3. This is performed for each of the WRITE POWER signals of 15 levels.

In the OPC operation, test writing to the test area is performed with the laser light having 15 levels of output in this manner.

When data is written to the optical disk 2, a read-out laser beam is emitted from the laser diode of the optical head 3 to the pre-groove of the optical disk 2, and the reflected light is received by the divided photodiode of the optical head 3. Is done.

The divided photodiode outputs a WOBBLE signal shown in FIG. As described above, the WOBBLE signal includes a signal having a frequency of 22.05 kHz at 1 × speed, and a signal obtained by performing biphase modulation on ATIP information and further performing FM modulation at a carrier frequency of 22.05 kHz.

The WOBBLE signal is input to the WOBBLE signal detection circuit 19 and is binarized by the WOBBLE signal detection circuit 19.

The binarized WOBBLE signal is a WOB signal.
This is input to the BLE servo controller 22.

In the WOBBLE servo controller 22, the FM-modulated AT of the WOBBLE signal is used.
The IP information is demodulated to obtain a BIDATA signal (bi-phase data signal) shown in FIG. This BIDATA signal is a signal (pulse signal) of 1T to 3T. Note that this BIDATA signal is bi-phase demodulated and then decoded to obtain ATIP information.

The WOBBLE servo controller 2
2, a digital PLL circuit (not shown) generates a clock based on the BIDATA signal,
The BICLOCK signal shown in FIG. 7 is obtained. This BICLO
The CK signal is used for decoding timing of a BIDATA signal described later.

The BIDATA signal and BICLOC
The K signals are input to the sync signal generation / ATIP decoder 27, respectively.

The sync signal generation / ATIP decoder 27 bi-phase demodulates the BIDATA signal based on the BICLOCK signal, and then decodes and decodes the ATIP signal.
Information is obtained, and an ATIP-SYNC signal (ATIP sync signal) shown in FIG. 7 is generated.

In this case, as shown in FIG.
When a SYNC pattern included in the A signal is detected, a pulse of the ATIP-SYNC signal is generated. The period of the pulse of the ATIP-SYNC signal (the interval between adjacent pulses) is 1/75 second at 1 × speed.

This ATIP-SYNC signal is input to each of the control means 13 and the WOBBLE servo controller 22.

The decoded ATIP information is input to the control means 13. The control means 13 grasps the absolute time on the optical disc 2 based on the ATIP information.

The SUBCODE-SYNC signal from the EFM / CDROM encoder control unit 24 is input to a sync signal generation / ATIP decoder 27.
And WOBBLE servo controller 22.

FIG. 8 is a diagram showing the format of an ATIP frame. As shown in the figure, the data of the ATIP frame is a 4-bit synchronization signal, that is, a sync (S
yn), an 8-bit minute (Min), an 8-bit second (Sec), an 8-bit frame, and a 14-bit error detection code (CRC: Cyclic Redundancy Code).

The WOBBLE servo controller 22 detects an error in the ATIP information for each ATIP frame (determines whether the ATIP information is incorrect).

In this ATIP information error detection, the ATI
"Normal" means that the result of performing a predetermined operation on the Sync, minute (Min), second (Sec) and frame data of the P frame matches the error detection code (CRC), Say "ATIP error."

In this case, as shown in FIG.
In the E servo controller 22, an error in the ATIP information,
That is, when an ATIP error is detected, a pulse 51 is generated and output.

ATIP E composed of this pulse 51
The RROR signal is input to a counter (counter) 131 of the controller 13. And this counter 13
1, the number of pulses of the ATIP ERROR signal becomes A
It is counted (measured) as a TIP error.

The error detection of the ATIP information is performed by the ATIP
Since it is performed for each frame, the ATIP error is 75 A
There are a maximum of 75 TIP frames (1 second at 1 × speed).

The WOBBLE servo controller 2
2 constitutes a detecting means for detecting an ATIP error.

The count value of the ATIP error is stored in the memory 26 and the interface control unit 3
1 and transmitted to the computer 41 for use in the inspection of the optical disk device 1 (determination of the recording capability of the optical disk device 1).

The ATIP-input to the control means 13
The SYNC signal is used for updating the ATIP time information.

The WOBBLE servo controller 2
2, the ATIP-SYNC signal is input to the SUBCO
Used for synchronization with the DE-SYNC signal.

SUBCODE input to the control means 13
The -SYNC signal is used for interpolation of ATIP time information and measurement of the ATIP error described above.

Further, the WOBBLE servo controller 2
The SUBCODE-SYNC signal input to 2 is used as a reference signal for synchronization, like the ATIP-SYNC signal.

The synchronization is performed in order to make the position of the SUBCODE-SYNC signal in the EFM data generated at the time of writing substantially coincide with the position of the ATIP-SYNC signal on the optical disk 2.

As shown in FIG. 9, SUBCODE-SY
The difference between the NC signal and the ATIP-SYNC signal is usually
± 2E at each part of the entire optical disc 2
Up to FM frames are allowed.

[Reproduction] When reproducing (reading) data (signal) from the optical disk 2, the WRITE POW from the laser control unit 14 is used.
The level of the ER signal is a constant D corresponding to the read output.
The output is held at the C level, whereby the output of the laser is held at the read output. The read output (output of the main beam) is usually set to 0.7 mW or less.

When reading data from the optical disk 2,
A read output laser beam is radiated from a laser diode of the optical head 3 onto a predetermined track of the optical disc 2,
The reflected light is received by the split photodiode of the optical head 3.

Each light receiving portion of the divided photodiode outputs a current (voltage) corresponding to the amount of received light, and these currents, ie, each signal (detection signal)
Each is input to the HF signal generation circuit 15 and the error signal generation circuit 18.

The HF signal generation circuit 15 generates an HF (RF) signal by adding or subtracting these detection signals.

The HF signal is an analog signal corresponding to pits and lands written on the optical disk 2.

This HF signal is input to the HF signal gain switching circuit 16 and amplified. The amplification factor (gain) of the HF signal gain switching circuit 16 is
Is switched by a gain switching signal from the controller.

The amplified HF signal (hereinafter simply referred to as “HF signal”
Signal) is input to each of the peak / bottom detection circuit 17 and the CD servo controller 21.

The peak / bottom detection circuit 17
A tracking error (TE) signal described in the focus control, tracking control, and sled control is input.

As shown in FIG. 10, the peak / bottom detection circuit 17 extracts an amplitude (envelope) of an input signal, for example, an HF signal or a tracking error signal.

The upper side of the amplitude is called PEEK (TOP), the lower side of the amplitude is called BOTTOM, the signal corresponding to the upper side of the amplitude is called a PEEK (TOP) signal, and the signal corresponding to the lower side of the amplitude is called a BOTTOM signal.

The PEEK signal and BOTTOM signal are
A (not shown) built in the control means 13
The signal is input to a / D converter, and is converted into a digital signal by the A / D converter.

The PEEK signal and the BOTTOM signal are used, for example, for measuring the amplitude, adjusting the amplitude of the tracking error signal, and using β in OPC (OPCTIMUM POWER CONTROL).
It is used for calculating (β value), determining the presence or absence of an HF signal, and the like.

In the CD servo controller 21, the HF signal is binarized, EFM demodulated, and an EFM signal is obtained. This EFM signal is a signal composed of pulses having a length (period) of 3T to 11T.

The CD servo controller 21 responds to the EFM signal by a CIRC (Cross Interl
Error correction (CIRC error correction) using an error correction code called “eaved Read Solomon Code” is performed twice.

In this case, the first CIRC correction is called C1 error correction, and the second CIRC correction is called C2 error correction.

A case where the first CIRC correction cannot be performed in the C1 error correction is referred to as “C1 error”, and a case where the second CIRC correction cannot be performed in the C2 error correction is referred to as “C2 error”.

As shown in FIG. 11, in the CD servo controller 21, when a C1 error is detected during the C1 error correction, a pulse 52 is generated and output.

C1ERROR composed of the pulse 52
The R signal is input to the counter 131 of the control means 13. The counter counts (measures) the number of pulses of the C1ERROR signal as a C1 error.

Since one subcode frame is composed of 98 EFM frames, the C1 error and the C2 error are
75 subcode frames each (1 second at 1x speed)
, There are a maximum of 7,350.

The CD servo controller 21 constitutes a detecting means for detecting a C1 error.

The count value of the C1 error is stored in the memory 26.
Is transmitted to the computer 41 via the interface control unit 31 and is used for the inspection of the optical disk device 1 (determination of the reproduction capability or the recording / reproduction capability of the optical disk device 1).

In the CD servo controller 21, the CIR
The EFM signal after the C error correction is decoded (converted) into data of a predetermined format, that is, a DATA signal.

Hereinafter, typically, audio data (music data) is recorded on the optical disc 2 and its EFM
A case where a signal is decoded into a DATA signal in an audio format will be described.

FIG. 12 is a timing chart showing the audio format DATA signal, LRCLOCK signal, and BITCLOCK signal.

As shown in the figure, in the CD servo controller 21, the EFM signal is composed of 16-bit L channel data and 16-bit R channel data based on the clock signal from the clock 33.
Decoded to ATA signal.

Further, in the CD servo controller 21,
BITC based on the clock signal from clock 33
A LOCK signal and an LRCLOCK signal are generated, respectively.

The BITCLOCK signal is a serial data transfer clock. The LRCLOCK signal is a signal for distinguishing L channel data and R channel data in the DATA signal. In this case, L
A high level (H) of the RCLOCK signal indicates L channel data, and a low level (L) indicates R channel data.

Even when ordinary data is recorded on the optical disc 2, the EFM signal is decoded into the above-mentioned DATA signal composed of 16-bit L-channel data and 16-bit R-channel data. .

The DATA signal, LRCLOCK signal and BITCLOCK signal are respectively
The data is input to the decoder control unit 28.

The CDROM decoder control unit 28 stores correction information, for example, ECC (Error Correc
If an error correction code of (Edtion Code) / EDC (Error Detecting Code) is recorded, the error correction is performed on the DATA signal.

The ECC / EDC is a CD-ROM M
This is an error correction code in the ODE1 format.
By this error correction, the bit error rate can be reduced to about 10 ⁻¹² .

In the CDROM decoder control section 28, the DATA signal is decoded into data of a predetermined format for communication (transmission) based on the clock signal from the clock 35, and the decoded data (decoded data) is Is transmitted to the computer 41 via the interface control unit 31.

On the computer 41 side, for example, the decoded data is encoded, and the encoded data (encoded data) is recorded (copied) on a predetermined recording medium (for example, an optical disk).

In the CD servo controller 21,
The FRAME SYNC signal shown in FIG. 13 is generated.

The level of the FRAME SYNC signal becomes high level (H) when the HF signal is input to the CD servo controller 21 and the EFM signal is synchronized at a specified period (3T to 11T). And HF
When a signal (EFM signal) is not input (when synchronization is lost), FRAME S is output in EFM frame units.
The level of the YNC signal changes from a high level (H) to a low level (L).

The length (period) of one EFM frame
Is 136 μsec at 1 × speed, and 98 EFM frames are one subcode frame.

The FRAME SYNC signal is input to the control means 13 and used for detecting the end of the HF signal.

The SUBQ DATA signal is input from the CD servo controller 21 to the control means 13.

This SUBQ DATA signal is a signal indicating Q data of the subcode data.

The sub codes include P, Q, R, S, T,
There are eight types, U, V and W. One EFM frame has one byte of subcode, and one byte of each of the data P to W is recorded in one byte.

Each data of P to W is 1 bit, and one subcode frame is a 98 EFM frame. Therefore, each data of P to W in one subcode frame is 98 bits. However, the first 2EF
Since the M frame is used for a SYNC pattern (synchronization signal), the actual data is 96 bits.

FIG. 14 is a diagram showing a format of 96 bits of Q data. The controls (4 bits) of Q1 to Q4 shown in FIG. 6 are used for discriminating normal data / audio data.

Addresses Q5 to Q8 (4 bits)
Indicates the contents of data (72 bits) from Q9 to Q80.

Also, the CRC (Cyclic R) of Q81 to Q96
The edundancy code (16 bits) is used for error (error) detection (determination of whether or not data is incorrect).

From the Q data, the absolute time information on the optical disc 2, the current track information, the lead-in, the lead-out, the music number, and the table of contents called TOC (Table Of Contents) recorded in the lead-in are further obtained. Contents and the like can be obtained.

The control means 13 obtains information from such Q data and performs predetermined control.

The SUBCODE-SYNC signal is input from the CD servo controller 21 to the control means 13.

As shown in FIG. 15, the 98 EFM frame has 98 bytes of subcode data. As described above, the two bytes of the first 2 EFM frames, ie, S0 and S1, have a SYNC pattern (synchronous signal). ) Is recorded.

In the CD servo controller 21, this S
When the YNC pattern is detected, a pulse is generated and output. That is, one subcode frame (98EF)
For every M frames), a pulse is generated and output. The signal composed of this pulse is SUBCODE-SYN
This is the C signal. The SYNC pattern is detected 75 times per second at 1 × speed.

In the CD servo controller 21,
After detecting the pulse of the SUBCODE-SYNC signal, the above-described Q data is updated. Then, the updated Q data is read into the control means 13.

[Focus Control, Tracking Control, and Thread Control] The error signal generation circuit 18 performs addition and subtraction of the detection signals from the divided photodiodes described above, and so on.
A focus error (FE) signal, a tracking error (TE) signal, and a thread error (SE) signal are respectively generated.

This focus error signal is a signal indicating the magnitude and direction of the shift of the objective lens from the focus position in the direction of the rotation axis (the shift amount of the objective lens from the focus position).

The tracking error signal is a signal indicating the magnitude of the displacement of the objective lens in the radial direction from the center of the track (pre-groove) and the direction (the amount of displacement of the objective lens from the center of the track).

The thread error signal is an error (error) signal used for thread control, that is, thread servo (feed servo of the optical head body of the optical head 3). In other words, it is a signal indicating the magnitude and direction of the displacement of the optical head 3 in the radial direction (the feed direction of the optical head 3) from the target position (proper position) of the optical head 3. The focus error signal is input to the CD servo controller 21.

The tracking error signal is input to the CD servo controller 21 and also to the peak / bottom detection circuit 17 as described above. The thread error signal is output from the CD servo controller 2
1 is input.

Using the focus error signal, tracking error signal and thread error signal, the optical disc device 1 performs focus control, tracking control and thread control on a predetermined track.

At the time of the focus control, the CD servo controller 21 controls the focus PWM (Puls Width Modulation) for controlling the driving of the actuator 4 in the rotation axis direction.
) A signal is generated. This focus PWM signal is
It is a digital signal (continuous pulse).

The focus PWM signal is input from the CD servo controller 21 to the PWM signal smoothing filter 7, and is smoothed by the PWM signal smoothing filter 7, that is, converted into a control voltage (control signal).
Is input to Then, the driver 6 applies a focus signal (predetermined voltage) to the actuator 4 based on the control voltage, and drives the actuator 4 in the rotation axis direction (focus direction).

In this case, the CD servo controller 21
Is to adjust the pulse width (duty ratio) of the focus PWM signal and invert the sign (positive or negative) of the focus PWM signal so that the level of the focus error signal becomes 0 (as much as possible). I do. Thereby, the objective lens of the optical head 3 is located at the focus position.
That is, focus servo is applied.

At the time of tracking control, the CD servo controller 21 generates a tracking PWM signal for controlling the radial driving of the actuator 4.
This tracking PWM signal is a digital signal (continuous pulse).

The tracking PWM signal is input from the CD servo controller 21 to the PWM signal smoothing filter 7, and smoothed by the PWM signal smoothing filter 7.
That is, it is converted into a control voltage (control signal) and input to the driver 6. The driver 6 applies a tracking signal (predetermined voltage) to the actuator 4 based on the control voltage, and drives the actuator 4 in the radial direction (tracking direction).

In this case, the CD servo controller 21
The tracking PWM is adjusted so that the level of the tracking error signal becomes zero (as much as possible).
The pulse width (duty ratio) of the signal is adjusted, and the sign (positive or negative) of the tracking PWM signal is inverted. Thereby, the objective lens of the optical head 3 is located at the center of the track (pre-groove). That is, tracking servo is applied.

At the time of thread control, the CD servo controller 21 generates a thread PWM signal for controlling the drive of the thread motor 5. This thread PW
The M signal is a digital signal (continuous pulse).

The thread PWM signal is input from the CD servo controller 21 to the PWM signal smoothing filter 7, smoothed by the PWM signal smoothing filter 7, that is, converted into a control voltage (control signal) and input to the driver 6. You. The driver 6 sends a sled signal (predetermined voltage) to the sled motor 5 based on the control voltage.
To drive the thread motor 5 to rotate.

In this case, the CD servo controller 21
Is to adjust the pulse width (duty ratio) of the thread PWM signal and to reverse the sign (positive / negative) of the thread PWM signal so that the level of the thread error signal becomes 0 (as much as possible). I do. Thereby, the optical head main body of the optical head 3 is located at the target position (appropriate position). That is, the thread servo is applied.

It is to be noted that, in addition to the tracking control, for example, the tracking error signal is transmitted from the optical head 3 to the
This is also used for control (track jump operation) when moving to a predetermined track (target track).

[Rotation Speed Control (Rotation Speed Control)] The optical disc apparatus 1 controls the rotation speed of the spindle motor 8 at 1 × speed, such as 1 × speed, 2 × speed, 4 × speed, 6 × speed, 8 × speed, and 12 × speed. Can be changed in multiple steps by an integer multiple of. This change is performed by setting the double speed switching mode.

For example, at the time of recording and reproduction, the rotation speed (rotation speed) of the spindle motor 8 is controlled in a state where the speed is set to a predetermined speed (in principle, the speed is described as 1 ×).

The method of controlling the number of revolutions includes WOBBLE.
A method of controlling with a PWM (Puls Width Modulation) signal, that is, a spindle servo (WOBBLE servo) using a WOBBLE signal, and an FG
A method of controlling with a PWM signal, that is, a spindle servo (FG servo) using an FG signal, and an EFM PWM
There is a method of controlling with a signal, that is, a spindle servo (EFM servo) using an EFM signal. Hereinafter, these will be sequentially described.

The WOBBLE PWM signal is WOBBL
This is a spindle motor control signal generated by the E servo controller (microprocessor) 22. Specifically, it is a digital signal (continuous pulse) of 0-5V level.

This WOBBLE PWM signal is
The signal is input from the BLE servo controller 22 to the PWM signal smoothing filter 12, smoothed by the PWM signal smoothing filter 12, that is, converted into a control voltage (control signal), and input to the driver 11. And driver 1
1 drives the spindle motor 8 to rotate based on the control voltage.

In this case, the WOBBLE servo controller 22 sets the pulse width (duty ratio) of the WOBBLE PWM signal so that the frequency (period) of the WOBBLE signal becomes a target value (for example, 22.05 kHz at 1 × speed). Adjust). Thus, the spindle servo is operated so that the rotation speed (rotation speed) of the spindle motor 8 becomes a target value (hereinafter, referred to as “target rotation speed”).

The FG PWM signal is a spindle motor control signal generated by the control means 13. In particular,
It is a digital signal (continuous pulse) of 0-5V level.

The FG PWM signal is output from the I / O port 134 of the control means 13 and is input to the PWM signal smoothing filter 12, and is smoothed by the PWM signal smoothing filter 12, that is, converted to a control voltage (control signal). The data is converted and input to the driver 11. And driver 1
1 drives the spindle motor 8 to rotate based on the control voltage.

On the other hand, the rotation speed of the spindle motor 8 is reduced by the motor rotation speed detection means to FG (Frequency Generator).
r) Detected as the frequency (period) of the signal. That is, the FG signal corresponding to the rotation speed (rotation speed) of the spindle motor 8 is output from the Hall element 9. This F
The G signal is binarized by the FG signal binarization circuit 23 into a square wave, and the frequency measurement unit (period measurement unit) of the control unit 13
132. Frequency measuring unit 13 of control means 13
2, based on the clock signal from the clock 32,
The frequency (period) of the FG signal is measured.

The control means 13 controls the FG PWM so that the frequency (period) of the FG signal becomes the target value.
Adjust the pulse width (duty ratio) of the signal. Thus, the spindle servo is operated so that the rotation speed (rotation speed) of the spindle motor 8 becomes the target rotation speed.

The frequency of the FG signal is
Is proportional to the number of revolutions. Therefore, for example, in the case of 6 × speed, 1
The frequency of the FG signal is six times that of the double speed.

The EFM PWM signal is a spindle motor control signal generated by the CD servo controller 21. Specifically, it is a digital signal (continuous pulse) of 0-5V level.

The EFM PWM signal is input from the CD servo controller 21 to the PWM signal smoothing filter 12, and is smoothed by the PWM signal smoothing filter 12.
That is, it is converted into a control voltage (control signal) and input to the driver 11. Then, the driver 11 drives the spindle motor 8 to rotate based on the control voltage.

In this case, the CD servo controller 21
Adjusts the pulse width (duty ratio) of the EFM PWM signal such that the period of a predetermined pulse of the EFM signal, that is, the pulse having a period of 3T to 11T, becomes a target value. Thus, the spindle servo is operated so that the rotation speed (rotation speed) of the spindle motor 8 becomes the target rotation speed.

In the above spindle servo,
The target number of revolutions of the spindle motor 8 differs between the inner circumference and the outer circumference of the optical disc 2 (the innermost circumference is 2.5 times the outermost circumference) in order to keep the linear velocity on the optical disc 2 constant. Therefore, in determining the target rotation speed, information on the radial position of the optical head 3 is considered together with information on what speed is currently set.

Information on the radial position of the optical head 3 is obtained from the absolute time on the optical disk. The absolute time is obtained from ATIP or SUB code Q data output from an ATIP decoder or a CD servo controller, and is input to the control means 13 to be grasped.

The WOBBLE PWM signal, F
At least one of various PWM signals such as a G PWM signal, an EFM PWM signal, a focus PWM signal, a tracking PWM signal, a thread PWM signal, and a PWM signal for controlling an eject motor is a pulse width modulation signal according to the present invention. It can be generated by a generating device. Hereinafter, a method of generating the FG PWM signal (a method of adjusting the pulse width (duty ratio)) will be representatively described.

Control means 13 comprising a microprocessor
Is a pulse width modulation signal generating apparatus according to the present invention, which has a built-in timer 133 that operates by counting a clock signal from the clock 32 and has an I / O port 134 as a 1-bit output terminal. I have. From this I / O port 134, an FG PWM signal, that is, a pulse width modulation signal is output. Further, the pulse width modulation signal generation device and the PWM signal smoothing filter 1
2 constitutes a motor control device of the present invention that controls the number of revolutions of the spindle motor 8.

FIGS. 16 and 17 are flowcharts showing the operation of generating a PWM signal according to the present invention, respectively. FIG. 17 shows an interrupt processing routine. FIG. 18 is a timing chart showing the waveform of the PWM signal. Hereinafter, description will be made based on these drawings.

First, a simple PWM mode is set (step 100), and initialization relating to the mode is performed (step 101). This initialization includes initialization of the timer 133 and setting of the frequency of the clock pulse from the clock 32 to be used.

Next, the Low period of the PWM signal is set in the timer 133 (step 102). This Low period is a period necessary for obtaining the target rotation speed.

Next, the PWM output port (I / O port 1)
34) is set to Low (step 103).

Next, the interruption of the timer 133 is permitted (step 104), the timer 133 is started (step 105), and the output of the PWM signal is started (step 106). When the timer 133 ends (time-up), the interrupt process is started, and the process proceeds to the interrupt process routine shown in FIG.

In this interrupt processing, first, the current PW
It is determined whether or not the setting of the M output port is a Low signal (step 200). If the signal is a Low signal, the PWM output port is set to a Hi signal (step 201), and the PWM is set.
The Hi period of the signal is set in the timer 133 (step 2).
02), the timer 133 is started (step 2)
05). Note that the Hi period set in the timer 133 is a period necessary for obtaining the target rotation speed.

If the result of determination in step 200 is that the signal is a Hi signal, the PWM output port is set to a low signal (step 203), and the low period of the PWM signal is set to the timer 133 (step 204).
Is started (step 205). Note that the Low period set in the timer 133 is a period necessary for obtaining the target rotation speed.

Timer 1 started in step 205
When 33 ends (time-up), step 20 is performed again.
0, and thereafter, until the output of the PWM signal is stopped.
Steps 200 to 205 are repeated.

When the output of the PWM signal is stopped by the determination in step 107, the interruption of the timer 133 is prohibited (step 108), and the output of the PWM signal is terminated (step 109).

As described above with reference to FIGS. 16 to 18, according to the optical disc apparatus 1 of the present invention, the microprocessor has a simple configuration, that is, a microprocessor having a 1-bit output terminal and having a timer function. By generating a pulse width modulation signal, it becomes possible to control the rotation of the spindle motor 8.

The optical disk device of the present invention is similar to the above-described CD.
-R drive device, other than this, for example, CD-R
The present invention can be applied to various optical disk devices for recording and reproducing various optical disks such as W, DVD-R, and DVD-RAM, and various optical disk devices for reproducing optical disks such as CD (compact disk) and CD-ROM.

As described above, the pulse width modulation signal generation device, the motor control device, and the optical disk device of the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this. , Can be replaced or omitted with any configuration having the same function.

[0175]

As described above, according to the present invention, a pulse width modulation signal capable of outputting a pulse width modulation signal with a simple configuration is generated, and the motor speed is controlled based on the pulse width modulation signal. It can be performed.

In particular, it is not necessary to separately provide a dedicated IC having a PWM signal output function, so that the configuration of the device can be prevented from becoming complicated and the cost can be prevented from increasing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a state where an optical disk device of the present invention is connected to a computer.

FIG. 2 is a block diagram showing an embodiment of the optical disk device of the present invention.

FIG. 3 is a timing chart showing an ENCODE EFM signal from an EFM / CDROM encoder control unit and an ENCODE EFM signal from a laser control unit according to the present invention.

FIG. 4 shows an ATIP-SYNC signal according to the present invention and SUBCODE from a sync signal generation / ATIP decoder;
6 is a timing chart showing a -SYNC signal and an ATIP ERROR signal.

FIG. 5 shows an ATIP-SYNC signal according to the present invention and a SUBCODE from a sync signal generation / ATIP decoder.
-SYNC signal and SU from CD servo controller
6 is a timing chart showing a BCODE-SYNC signal.

FIG. 6 shows 1T Biphase ATI according to the present invention.
P timing, WOBBLE signal, WO after binarization
6 is a timing chart showing a BLE signal.

FIG. 7 shows a BIDATA signal and BICL according to the present invention.
5 is a timing chart showing an OCK signal and an ATIP-SYNC signal.

FIG. 8 is a diagram showing a format of an ATIP frame according to the present invention.

FIG. 9 shows an ATIP-SYNC signal and S
6 is a timing chart showing a UBCODE-SYNC signal.

FIG. 10 shows an input signal to a peak / bottom detection circuit according to the present invention, the amplitude (envelope) of the input signal,
6 is a timing chart showing a PEEK signal and a BOTTOM signal.

FIG. 11 is a timing chart showing a SUBCODE-SYNC signal and a C1ERROR signal from a CD servo controller according to the present invention.

FIG. 12 is a timing chart showing a DATA signal, an LRCLOCK signal, and a BITCLOCK signal in an audio format according to the present invention.

FIG. 13 shows a SUBCODE-SYNC signal from a CD servo controller and FRAME SY in the present invention.
6 is a timing chart showing an NC signal and an HF signal (EFM signal).

FIG. 14 is a diagram showing a format of 96 bits of Q data according to the present invention.

FIG. 15 is a diagram showing one subcode frame in the present invention.

FIG. 16 is a flowchart showing a PWM signal generation operation according to the present invention.

FIG. 17 is a flowchart illustrating a PWM signal generation operation (interrupt processing routine) according to the present invention.

FIG. 18 is a timing chart showing a waveform of a PWM signal.

[Explanation of symbols]

 Reference Signs List 1 optical disk device 10 casing 2 optical disk 3 optical head (optical pickup) 4 actuator 5 thread motor 6 driver 7 PWM signal smoothing filter 8 spindle motor 9 Hall element 11 driver 12 PWM signal smoothing filter 13 control means 131 counter 132 frequency measuring unit (period) Measurement unit) 133 Timer 134 I / O port 14 Laser control unit 15 HF signal generation circuit 16 HF signal gain switching circuit 17 Peak / bottom detection circuit 18 Error signal generation circuit 19 WOBBLE signal detection circuit 21 CD servo controller 22 WOBBLE servo controller 23 FG signal binarization circuit 24 EFM / CDROM encoder control unit 25, 26 Memory 27 Sync signal generation / ATIP decoder 28 CD OM decoder control unit 29 memory 31 interface control unit 32 to 35 clock 36 address data bus 41 computer 42 keyboard 43 mouse 44 monitor (CRT) 51 and 52 pulses 100-109 Step 200-205 Step

Claims (6)

[Claims] 1. A pulse width modulation signal generation device having a microprocessor having a timer function and having a 1-bit output terminal, and outputting a pulse width modulation signal from the output terminal, wherein a setting time of the timer is set. The pulse width modulation signal generating apparatus is configured to change the duty ratio of the pulse width modulation signal by changing the pulse width modulation signal. 2. A pulse width modulation signal generating device having a microprocessor having a timer function and having a 1-bit output terminal and outputting a pulse width modulation signal from said output terminal, comprising: A pulse width modulation signal generating apparatus, wherein the periods of the Low signal and the Hi signal are set by the timer. 3. A pulse width modulation signal generating device having a microprocessor having a timer function and having a 1-bit output terminal, outputting a pulse width modulation signal from said output terminal, and smoothing said pulse width modulation signal. And a smoothing circuit that outputs the pulse width modulated signal by controlling the number of revolutions of the motor based on an output value from the smoothing circuit. A motor control device configured to change a duty ratio of the motor. 4. A pulse width modulation signal generating device having a microprocessor having a timer function and having a 1-bit output terminal, outputting a pulse width modulation signal from said output terminal, and smoothing said pulse width modulation signal. A motor control device that controls the number of revolutions of the motor based on an output value from the smoothing circuit, wherein a period of the Low signal and a period of the Hi signal output from the output terminal are respectively set. The motor control device is set by the timer. 5. An optical disk device for recording and / or reproducing an optical disk, comprising: a motor for driving the optical disk to rotate; and the motor control device according to claim 3 or 4. . 6. An optical disk apparatus for recording and / or reproducing an optical disk, wherein the motor drives the optical disk to rotate, and a motor rotation number detecting unit detects the number of rotations of the motor. A motor control device, wherein a setting time of the timer in the motor control device is changed in accordance with a motor rotation speed detected by the motor rotation speed detection means, and a voltage applied to the motor is adjusted. An optical disk device characterized by controlling the number of rotations of the optical disk.