JP2001176172A - Disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the burden of a power supply source (battery) by suppressing the power consumption due to a spindle motor to the minimum in a portable CD-ROM drive or a CD player. SOLUTION: By a microcomputer, the increase/decrease of data amount in a buffer memory is monitored. When the data amount in the buffer memory becomes the specified amount or larger, the power supplied to the spindle motor is interrupted by the micro-computer and the data are read out till the out of synchronizm of PLL is generated while making the motor rotate by the inertia. When the read-out of the data becomes impossible, an address just before that time is stored, and also the driving control of the pickup is stopped. Further, when the data amount of the buffer memory becomes smaller than the specified amount, the power is supplied to the spindle motor to increase the number of rotation, and the focus and tracking control are started for a pickup, and when the PLL is synchronized, the pickup is positioned to the address previously being held, then the read-out of the data is restarted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an optical disk reproducing apparatus. More specifically, the present invention relates to a technology for reducing power consumption of a battery-driven optical disk device such as a portable CD-ROM drive, audio CD player, and MD player.

[0002]

2. Description of the Related Art Like a so-called portable CD player, portable CD-ROM drive, and portable MD player,
Portable optical disk devices are widely available on the market. The power consumption of these portable optical disk devices often poses a problem. It is desirable that portable devices consume as little power as possible. Particularly, in an audio CD player or an MD player performing a continuous reproduction operation, power is continuously consumed, so that a load on a battery is large. Therefore, in the case of a portable optical disk device, taking into account the improvement of impact resistance,
A relatively large-capacity buffer memory is mounted, and the optical disk is driven to rotate faster than a normal speed to perform intermittent reproduction. Such a technique is disclosed in, for example,
It is publicly known in 38314 publication and the like. Japanese Patent Application Laid-Open No. 11-238314 discloses a technique of a portable optical disk device such as a portable CD player. When the buffer memory is full of data read from the optical pickup, the reproducing operation is interrupted and the servo information at that time is held.
Then, when the remaining amount of data in the buffer memory falls below a certain amount, the servo information previously held is read out, accompanied by a quick servo pull-in operation, and a reproducing operation is started.

[0003]

However, the demands on the market are severe, and a longer playback time is required. The present invention solves this problem, reduces power consumption compared to conventional devices,
In particular, an optical disk reproducing device suitable for battery driving is provided.

[0004]

In order to solve the above-mentioned problems, the present invention proposes a disk reproducing apparatus having the following features. (a) A spindle motor for rotating a disk-shaped recording medium in which digital information including a clock component is recorded as a signal together with address information. (b) A spindle motor driver for driving the spindle motor. (c) a pickup for reading a signal from the disk. (d) a pickup driver for driving the pickup in a radial direction of the disk. (e) a PLL for extracting the clock component from a signal read from the pickup. (f) a reproduction signal processing unit that demodulates data from the signal using a clock obtained from the PLL. (g) A buffer memory for temporarily storing and outputting data obtained from the reproduction signal processing unit. (h) control means connected to the buffer memory, the PLL, the spindle motor driver, and the pickup driver. This control means has the following features. (h-1) When the data stored in the buffer memory reaches a predetermined capacity, the spindle motor driver is controlled to stop or reduce the power supply of the spindle motor. (h-2) When detecting that the PLL is out of synchronization from the time point of the above (h-1), stop writing data to the buffer memory and stop driving the pickup driver, and stop the address at that time. Store the information.

[0005] Further, in order to solve the above problems, the present invention proposes a disk reproducing apparatus having the following features. (a) A spindle motor for rotating a disk-shaped recording medium in which digital information including a clock component is recorded as a signal together with address information. (b) A spindle motor driver for driving the spindle motor. (c) a pickup for reading a signal from the disk. (d) a pickup driver for driving the pickup in a radial direction of the disk. (e) a PLL for extracting the clock component from a signal read from the pickup. (f) a reproduction signal processing unit that demodulates data from the signal using a clock obtained from the PLL. (g) A buffer memory for temporarily storing and outputting data obtained from the reproduction signal processing unit. (h) control means connected to the buffer memory, the PLL, the spindle motor driver, and the pickup driver. This control means has the following features. (h-1) The data stored in the buffer memory is the
When the predetermined capacity is reached, the spindle motor driver is controlled to stop or reduce the power supply of the spindle motor. (h-2) When detecting that the PLL is out of synchronization from the time point of the above (h-1), stop writing data to the buffer memory and stop driving the pickup driver, and stop the address at that time. Store the information. (h-3) a spindle that has been stopped or reduced when the data stored in the buffer memory has reached a second predetermined capacity smaller than the first predetermined capacity since the time of (h-2). The spindle motor driver is controlled so as to restart the driving of the motor in the normal reproduction state. (h-4) When it is detected that the PLL is synchronized again from the time point (h-3), the drive of the pickup driver is restarted to drive the pickup to the address information position where the pickup is stored. (h-5) When the address information position stored by the pickup has been reached from the point in time (h-4), the writing of data to the buffer memory is restarted.

[0006] It is more preferable that the control means has the following features. (a) When the data stored in the buffer memory reaches a predetermined capacity, the spindle motor driver is controlled to stop or reduce the power supply of the spindle motor, and the address information at that time is used as first address information. Remember. (b) If it is detected that the PLL is out of synchronization from the time point (a), the writing of data to the buffer memory is stopped, and the driving of the pickup driver is stopped, and the address information at that time is stored in the second memory. 2 is stored as the address information. (c) calculating and setting a new spindle motor stop threshold for the buffer memory from the data amount obtained from the first and second address information obtained in (a) and (b).

Further, it is more preferable that the control means has the following features. (a) The data stored in the buffer memory is the first
When the predetermined capacity is reached, the spindle motor driver is controlled so as to stop or reduce the power supply to the spindle motor, and the address information at that time is stored as first address information. (b) If it is detected that the PLL is out of synchronization from the time point (a), the writing of data to the buffer memory is stopped, and the driving of the pickup driver is stopped, and the address information at that time is stored in the second memory. 2 is stored as the address information. (c) from the data amount obtained from the first and second address information obtained in (a) and (b), the first predetermined value as a new spindle motor stop threshold of the buffer memory. Calculate and set the capacity. (d) when the data stored in the buffer memory reaches a second predetermined capacity that is smaller than the first predetermined capacity, the spindle motor is stopped or restarted to resume power supply of the reduced spindle motor. Controlling the driver and restarting the driving of the pickup driver,
The time measurement is started from that point. (e) When it is detected that the PLL is synchronized again from the time point (d), the pickup is driven to the address information position in which the pickup is stored. (f) When the pickup reaches the address information position stored from the time of (e), the writing of data to the buffer memory is restarted and the measurement of the time started in (d) is stopped. The second predetermined capacity is calculated and set as a new spindle motor drive restart threshold of the buffer memory from the obtained time information.

[0008]

[Operation and Effect] With the recent development of CD signal processing technology,
PLLs have very wide capture and lock ranges. This means that the PLL can follow even if the disk rotation speed changes from a low speed to a high speed. Therefore, even if the power supply to the spindle motor is stopped, it is possible to keep the PLL locked as much as possible while the disk continues to rotate by inertia. Stopping the reproducing operation in this state is obviously a matter of power. Therefore, the microcomputer shuts off the power supplied to the spindle motor when the amount of data in the buffer memory exceeds a certain amount, and reads data while rotating by inertia until the PLL loses synchronization. When the data cannot be read, the address immediately before that is stored and the drive control of the pickup is stopped. When the data amount of the buffer memory becomes equal to or less than a certain amount, the rotation drive of the spindle motor is restarted, and the focus and tracking control of the pickup is started. When the PLL is synchronized, the pickup is positioned at the previously held address, and data reading is resumed. This makes it possible to use the power supplied to the spindle motor as effectively as possible to reproduce data.

Further, if the address at the time of stopping the spindle motor is also held, the amount of data read up to the time when the PLL is no longer locked can be grasped. This makes it possible to perform very efficient spindle motor stop control.

[0010] Further, by measuring the time from the time when the rotation of the spindle motor is restarted and holding the time until the time when the reading can be restarted, the minimum data amount to be left in the buffer memory can be grasped from the time. Therefore, this can be used as a new threshold value for resuming spindle motor drive, and extremely efficient spindle motor drive resumption control can be performed.

[0011] The components described in each claim are as follows. (a) is a spindle motor for driving a disk. The disc is a CD-DA, CD-ROM, or MD.
These are all assumed to be driven by a CLV, and a digital signal including a clock is recorded. In the embodiment described later, the spindle motor is a CAV. (b) is a spindle motor driver including transistors and the like. (c) includes an optical pickup and a sled drive system. The operation of this pickup drive control is mainly for controlling the positioning of the light beam to a predetermined address. (d) conceptually includes a driver for sled drive control of the pickup and tracking drive control and focus control of the lens from the description of (c). (e) is a PLL for extracting a synchronization clock from the reproduction signal. (f) is a reproduction signal processing unit for demodulating data using a synchronous clock obtained from the PLL.
(g) is a buffer memory and a memory controller for temporarily storing and outputting data obtained from the reproduction signal processing unit, and the buffer memory corresponds to this. (h) is a microcomputer, which receives memory remaining amount information from the memory controller of the buffer memory, receives synchronous / asynchronous determination information from the PLL, controls on / off control of the spindle motor driver, on / off control of the pickup driver, and Turns on / off data storage for the memory controller. In order to reset the threshold value for writing data to the buffer memory, the address information when the power supply to the spindle motor was stopped, the address information when the PLL became out of synchronization, and the drive of the spindle motor were restarted. The time from the point of time to when the address information at the time of the last read is reached is measured and stored.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

[0013]

FIG. 1 is a block diagram of a CD player embodying the present invention. The CD player 1 is a portable CD player driven by a battery (not shown). The disk 3 is a well-known audio CD, and digital audio data is spirally recorded on an information recording surface by well-known EFM modulation. The spindle motor 4 drives the disk 3 to rotate. Although a normal CD player is driven to rotate by CLV control, the CD player 1 according to the present invention drives the spindle motor 4 to rotate at a constant angular speed higher than the rotation speed of normal CLV control. Spindle motor driver 7
Is a transistor, which adjusts the power supplied through the first switch 8 by the servo signal output from the servo circuit 6 and supplies the power to the spindle motor 4. However, since the CD player according to the present invention is in the CAV control, the servo circuit 6 does not perform a control operation for substantially adjusting the rotation speed like the CLV.

The optical pickup 5 is a well-known type, and includes a laser diode (not shown) for irradiating the disk 3 with laser light, a lens (not shown) for receiving light reflected from the information recording surface of the disk 3, and a light for receiving light passing through the lens. And a photodetector (not shown) for converting the electric signal into an electric signal.

In order to cause a lens (not shown) to follow an information track provided on the information recording surface of the disk 3, the servo circuit 6 includes a focus error signal obtained from a signal obtained from the pickup unit 5 through a control signal processing unit 13, Focus control and tracking control are performed via the focus / tracking control driver 11 using the tracking error signal. The optical pickup 5 is driven in the radial direction of the disk 3 by a seek motor (not shown).

In order to drive and control a seek motor (not shown),
The servo circuit 6 controls the drive of the pickup 5 in the radial direction of the disk 3 through the seek drive driver 9 based on a control signal issued from the microcomputer 14.

A first switch 8 for turning on / off the power supply under the control of the microcomputer 14 is connected to the driver 7 that drives the spindle motor 4 to rotate. pick up
Seek drive driver that drives 5 in the radial direction of disk 3
9 is connected to a second switch 10 for controlling on / off of the power supply under the control of the microcomputer 14. To a focus / tracking control driver 11 for performing focus / tracking control of a lens (not shown) of the pickup 5, a third switch 12 for controlling on / off of power supply under the control of the microcomputer 14 is connected.

A reproduction signal obtained from the pickup 5 is supplied to a control signal processing unit 13, a PLL 15, and a reproduction signal processing unit 16. The control signal processing unit 13 is a circuit that extracts a focus error signal and a tracking error signal from the reproduction signal and supplies the signal to the servo circuit 6. The PLL 15 synchronizes with the clock component of the reproduction signal to generate a synchronization clock required by the reproduction signal processing unit 16 for demodulation of the reproduction signal. Further, the PLL 15 outputs a synchronous / asynchronous determination detection signal and supplies the signal to the microcomputer 14. The reproduction signal processing unit 16 demodulates data from the reproduction signal by a synchronous clock obtained from the PLL 15 and also demodulates address information included in the reproduction signal, and supplies the demodulated data to the microcomputer 14. The demodulated digital data obtained from the reproduction signal processing unit 16 is stored in a large-capacity buffer memory 17 through a memory controller 18. Memory controller
The microcomputer 18 is connected to the microcomputer 14, monitors the memory capacity of the buffer memory 17, and controls storage of data obtained from the reproduction signal processing unit 16. The microcomputer 14 includes a display unit (not shown) and an operation unit (not shown), and performs a reproduction operation of the disk 3 in accordance with an operation performed by the user through the operation unit, and displays information such as an operation status on the display unit (not shown). Is displayed.

[0019]

[Operation] The operation will be described below with reference to FIG.

FIG. 2 is a schematic diagram showing a reproducing operation of the CD player 1 according to the present invention. In order to facilitate the description, parts other than the disk 3, the spindle motor 4, the pickup 5, and the buffer memory 17 are not shown.

In FIG. 2A, when a user gives a reproduction command to the CD player 1 through an operation unit (not shown), the microcomputer 14 operates the first switch 8, the second switch 10, and the third switch.
At the same time as turning on 12, the spindle circuit 4 and the pickup 5 are drive-controlled through the servo circuit 6 to start the reproducing operation. At this time, the spindle motor 4 is rotationally driven by CAV, which is faster than the normal CLV control rotational speed. That is, since the transfer speed of the demodulated digital data obtained from the pickup 5 through the reproduction signal processing unit 16 is faster than the transfer speed of the demodulated digital data read from the buffer memory 17, the empty buffer memory 17 is the one shown in FIG. As shown in FIG. The capacity of the demodulated digital data stored in the buffer memory 17 is controlled by the microcomputer
Checked by 14.

In FIG. 2C, the microcomputer 14 has a buffer memory.
When the capacity of the demodulated digital data stored in 17 occupies 80% of the whole, it is judged that this has reached the threshold value inside the microcomputer 14, and the first switch 8 is controlled to control the spindle motor driver. Cut off the power supply to 7. Then, the microcomputer 14 acquires from the reproduction signal processing unit 16 the address information which is the reproduction position of the pickup 5 on the disk 3 at the time when the power supply to the spindle motor driver 7 is cut off, and stores it as the first address information. Since the power supply to the spindle motor 4 is cut off, the spindle motor 4 continues to rotate by inertia, and soon stops rotating due to friction of a rotating shaft portion (not shown) of the spindle motor 4. However, the PLL 15 generates a synchronization clock in synchronization with the reproduction signal as much as possible. As long as a synchronous clock is obtained, demodulation of a reproduced signal is possible.

Until the PLL 15 loses synchronization, the microcomputer 14 continues to check the free space of the buffer memory 17, and FIG.
When the free space runs out as shown in FIG. Even if storage of demodulated digital data is stopped,
As shown in FIG. 2 (e), while the demodulated digital data is in the buffer memory 17, the reproduction can be continued.

In FIG. 2 (f), when the PLL 15 loses synchronization, the microcomputer 14 obtains, from the reproduction signal processing unit 16, address information indicating the reproduction position of the pickup 5 on the disk 3 at that time, and outputs the second address. The information is stored as information, and the second switch 10 and the third switch 12 are turned off to stop the seek control of the pickup 5, the tracking / focus control, and the light emission of the laser diode. At this point, the amount of demodulated data from when the power supply to the spindle motor 4 is cut off until the PLL 15 loses synchronization can be grasped. With this data amount, the buffer memory 17
A new threshold value for stopping the spindle motor 4 can be set. Even when the spindle motor 4 is stopped, the reproduction can be continued while the demodulated digital data is in the buffer memory 17.

In FIG. 2 (g), when the microcomputer 14 detects that the capacity of the demodulated digital data in the buffer memory 17 has dropped below 20%, the microcomputer 14 turns on the first switch 8 and supplies power to the spindle motor driver 7. Is supplied, the third switch 12 is turned on, the light emission of the laser diode of the pickup 5 is restarted, and the tracking / focus control is restarted. Thus, the rotation of the spindle motor 4 starts, and the pickup 5 follows the information track on the disk 3. At the same time, the microcomputer 14 starts an internal timer and starts measuring time.

In FIG. 2 (h), when the PLL 15 starts to synchronize, the microcomputer 14 controls the second switch 10 to be turned on to perform seek control of the pickup 5 to the second address information. Restart the data demodulation operation. Then, the microcomputer 14 stops the internal timer, and stores time information from the start of the spindle motor 4 until data demodulation becomes possible. By multiplying this time information by the data transfer rate output from the memory controller 18, the buffer memory
The minimum amount of data that must remain in 17 can be calculated. With this data capacity, the buffer memory 17
A new threshold value for restarting the spindle motor 4 can be set.

[0027]

[Application Examples] The present invention is not limited to the above-described embodiment, and the following applications are possible. (1) Although the embodiment is an optical disk device, the present invention is also applicable to a magnetic disk device. In the case of a magnetic disk device, the magnetic head does not require focus / tracking control unlike the optical disk device, and can be implemented only by the seek control of the magnetic head. (2) It is preferable to set a margin for the threshold value for stopping and restarting the spindle motor in consideration of safety.
Further, it is more preferable that the focus / tracking signal of the pickup is monitored to detect the vibration, whereby the operating environment of the apparatus is grasped, and the margin is increased or decreased accordingly.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a CD player according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a reproducing operation of a CD player according to an embodiment of the present invention.

[Explanation of symbols]

 1 CD player 3 Disc 4 Spindle motor 5 Pickup 6 Servo circuit 7 Spindle motor driver 8 First switch 9 Seek drive driver 10 Second switch 11 Focus / tracking control driver 12 Third switch 13 Control signal processing unit 14 Microcontroller 15 PLL 16 Playback signal processor 17 Buffer memory 18 Memory controller 19 Output pin

Claims (4)

[Claims] 1. A disk reproducing apparatus having the following configuration requirements. (a) A spindle motor for rotating a disk-shaped recording medium in which digital information including a clock component is recorded as a signal together with address information. (b) A spindle motor driver for driving the spindle motor. (c) a pickup for reading a signal from the disk. (d) a pickup driver for driving the pickup in a radial direction of the disk. (e) a PLL for extracting the clock component from a signal read from the pickup. (f) a reproduction signal processing unit that demodulates data from the signal using a clock obtained from the PLL. (g) A buffer memory for temporarily storing and outputting data obtained from the reproduction signal processing unit. (h) control means connected to the buffer memory, the PLL, the spindle motor driver, and the pickup driver. This control means has the following features. (h-1) When the data stored in the buffer memory reaches a predetermined capacity, the spindle motor driver is controlled to stop or reduce the power supply of the spindle motor. (h-2) When detecting that the PLL is out of synchronization from the time point of the above (h-1), stop writing data to the buffer memory and stop driving the pickup driver, and stop the address at that time. Store the information. 2. A disc reproducing apparatus having the following configuration requirements. (a) A spindle motor for rotating a disk-shaped recording medium in which digital information including a clock component is recorded as a signal together with address information. (b) A spindle motor driver for driving the spindle motor. (c) a pickup for reading a signal from the disk. (d) a pickup driver for driving the pickup in a radial direction of the disk. (e) a PLL for extracting the clock component from a signal read from the pickup. (f) a reproduction signal processing unit that demodulates data from the signal using a clock obtained from the PLL. (g) A buffer memory for temporarily storing and outputting data obtained from the reproduction signal processing unit. (h) control means connected to the buffer memory, the PLL, the spindle motor driver, and the pickup driver. This control means has the following features. (h-1) The data stored in the buffer memory is the
When the predetermined capacity is reached, the spindle motor driver is controlled to stop or reduce the power supply of the spindle motor. (h-2) When detecting that the PLL is out of synchronization from the time point of the above (h-1), stop writing data to the buffer memory and stop driving the pickup driver, and stop the address at that time. Store the information. (h-3) a spindle that has been stopped or reduced when the data stored in the buffer memory has reached a second predetermined capacity smaller than the first predetermined capacity since the time of (h-2). The spindle motor driver is controlled so as to restart the driving of the motor in the normal reproduction state. (h-4) When it is detected that the PLL is synchronized again from the time point (h-3), the drive of the pickup driver is restarted to drive the pickup to the address information position where the pickup is stored. (h-5) When the address information position stored by the pickup has been reached from the point in time (h-4), the writing of data to the buffer memory is restarted. 3. The disk reproducing apparatus according to claim 1, wherein said control means has the following characteristics. (a) When the data stored in the buffer memory reaches a predetermined capacity, the spindle motor driver is controlled to stop or reduce the power supply of the spindle motor, and the address information at that time is used as first address information. Remember. (b) If it is detected that the PLL is out of synchronization from the time point (a), the writing of data to the buffer memory is stopped, and the driving of the pickup driver is stopped, and the address information at that time is stored in the second memory. 2 is stored as the address information. (c) calculating and setting a new spindle motor stop threshold for the buffer memory from the data amount obtained from the first and second address information obtained in (a) and (b). 4. The disk reproducing apparatus according to claim 2, wherein said control means has the following characteristics. (a) The data stored in the buffer memory is the first
When the predetermined capacity is reached, the spindle motor driver is controlled so as to stop or reduce the power supply to the spindle motor, and the address information at that time is stored as first address information. (b) If it is detected that the PLL is out of synchronization from the time point (a), the writing of data to the buffer memory is stopped, and the driving of the pickup driver is stopped, and the address information at that time is stored in the second memory. 2 is stored as the address information. (c) from the data amount obtained from the first and second address information obtained in (a) and (b), the first predetermined value as a new spindle motor stop threshold of the buffer memory. Calculate and set the capacity. (d) when the data stored in the buffer memory reaches a second predetermined capacity that is smaller than the first predetermined capacity, the spindle motor is stopped or restarted to resume power supply of the reduced spindle motor. Controlling the driver and restarting the driving of the pickup driver,
The time measurement is started from that point. (e) When it is detected that the PLL is synchronized again from the time point (d), the pickup is driven to the address information position in which the pickup is stored. (f) When the pickup reaches the address information position stored from the time of (e), the writing of data to the buffer memory is restarted and the measurement of the time started in (d) is stopped. The second predetermined capacity is calculated and set as a new spindle motor drive restart threshold of the buffer memory from the obtained time information.