JP2009517789A - System and method for minimizing power consumption while recording data on an optical disc - Google Patents

Abstract

  The present invention relates to a data record comprising a read / write head (OH) for reading / writing data on a data record carrier (OM), and a turntable motor (TM) for rotating the data record carrier (OM). The present invention relates to a system and method for operating a device (DRD). Said method is based on a frequency profile defining the rotational frequency of the turntable motor (TM) as a function of the position (R) of the read / write head (OH) on the data record carrier (OM). Generating a control signal (STM) for changing the rotational frequency (f). The frequency profile includes a first portion (CLV) followed by a second portion (VLV), during which the rotational frequency is reduced from a start frequency to an intermediate frequency, and the second portion During the part, the rotation frequency is increased from the intermediate frequency to the final frequency.

Description

  The present invention relates to a method for operating a data recording apparatus and a data recording apparatus for realizing such a method.

  A particular field of application of the present invention relates to an optical data recording device that uses a laser to both read and write data on an optical disc.

  The relative speed V of the data points on the rotating optical disk with respect to the optical head is V = r. can be expressed as ω. Here, r is the distance between the data point and the center of the optical disk, that is, the radius, and ω is the rotational speed of the spindle motor that rotates the optical disk. One of the three variables V, r, ω must be constant. Since the radius r depends on the position of the data point, only V or ω can be constant. Thus, the spindle motor can generally rotate the optical disc according to either a constant linear velocity mode or a constant angular velocity mode.

  When the servo system that controls the position of the optical head keeps the relative speed V constant, the rotation mode of the spindle motor is called constant linear velocity. The advantage of this mode is that the data transfer rate is kept fixed and the phase lock loop can only maintain correct data reading by locking the fixed frequency. However, the rotational speed of the spindle motor must change synchronously with respect to the position of the optical head. If the rotational speed continues to increase to some extent, it must be considered whether the spindle motor can achieve a predetermined high speed when the optical head is in the inner track.

  When the servo system keeps the rotation speed ω constant, the rotation mode is called constant angular velocity. Since the spindle motor rotates at a fixed angular velocity different from the constant linear velocity, it is easier to control the spindle motor in this mode. However, the data transfer rate in the outer track is higher than that of the inner track. Therefore, the data read must be followed to change the fundamental frequency that should be locked when the phase lock loop is in constant angular velocity mode.

  Optical drive systems (eg for CD-ROMs) are typically calibrated to obtain maximum system margin (ie, processing disturbances such as offset without read / write errors), maximum data transfer rate, or short access time. Constant angular velocity mode or constant linear velocity mode results in an increase in power consumption of the optical drive system and thus an increase in power loss to the optical drive system.

  The object of the present invention is to propose a method of operating a data recording device which overcomes at least one of the disadvantages of the prior art and in particular makes it possible to minimize the power loss of the data recording device.

  For this purpose, a data record comprising a read / write head (OH) for reading / writing data on a data record carrier (OM) and a turntable motor (TM) for rotating the data record carrier (OM). A method for operating a device (DRD) is proposed.

This method involves the rotation according to a frequency profile that defines the rotational frequency (f) of the turntable motor (TM) as a function of the position (R) of the read / write head (OH) on the data record carrier (OM). Generating a control signal (S _TM ) for changing the frequency (f).

  The frequency profile includes a first portion (CLV) in which a rotation frequency is decreased from a start frequency to an intermediate frequency, and after the first portion (CLV), the rotation frequency is changed from the intermediate frequency to the final frequency. Followed by a second portion (VLV) which is increased to

  Optionally, the rotational frequency can be reduced substantially linearly along the first portion. The rotational frequency can be increased substantially linearly along the second portion.

  Advantageously, the intermediate frequency corresponds to the determined position of the read / write head on the data record carrier.

  Advantageously, the determined position of the read / write head is adjustable.

  The determined position of the read / write head may correspond to the outer area of the data record carrier.

  According to another aspect, the invention relates to a computer program product for a data recording device comprising a set of instructions which, when loaded into the data recording device, cause the data recording device to perform the method according to the invention.

  According to another aspect, the present invention provides a read / write head for reading / writing data on a data record carrier that can be inserted into a data recording device, a turntable motor for rotating the data record carrier, and a turntable motor. The present invention relates to a data recording device having an electronic device coupled to. The electronic device operates the turntable motor according to the steps of the method according to the invention.

  Advantageously, the rotational frequency can be reduced from the starting frequency to the intermediate frequency so that the core current of the electronic device is kept constant.

  The adaptive frequency profile of the present invention makes it possible to reduce the power loss of the drive module that controls the turntable motor. Due to the reduced clock frequency and core current of the electronic device linked to the adaptive frequency profile of the present invention, the present invention further provides other configurations of data recording devices (eg, thread motors, read / write head elements, etc.). It makes it possible to reduce the power loss in the drive module controlling the element.

  These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.

  The present invention has been described through examples and is not limited to the accompanying drawings, in which like reference numerals indicate like elements.

  FIG. 1 is a block diagram schematically and partially showing a data recording device DRD. The data recording device DRD performs operations relating to both reading and writing of information on the data record carrier OM. The data recording device includes a read / write head OH, a turntable motor TM (also called a spindle motor), a thread motor SM, and an electronic device EA.

  A data record carrier OM is shown inserted in the recording device. The data record carrier OM can be an optical disc. The surface of the optical disc can include a single spiral that runs from the inside of the disc to the outside of the disc. The binary information recorded on the track is represented by optically detectable parts, ie marks and spaces. Marks and spaces can be detected by their different optical properties, such as variations in the reflection of the laser beam.

  The read / write head OH has a radiation source, such as a laser diode, which generates a radiation beam, for example a laser beam. By controlling the power of the laser beam, it is possible to read or write information on the data record carrier OM. The read / write head OH further comprises various optical elements for guiding and focusing the laser beam on the track of the data record carrier OM. The read / write head OH further comprises a detector, for example a four quadrant diode, which detects and measures the laser beam reflected by the optically detectable part on the data record carrier track.

  The turntable motor TM rotates the data record carrier OM according to an angular velocity ω proportional to the rotation frequency. The rotational frequency determines the read / write mode and speed associated with the data recording device DRD.

  The thread motor SM controls the radius R, that is, the position of the read / write head OH with respect to the track. The position R indicates the distance between the central axis AX of the data record carrier OM and the focusing spot FS of the laser beam emitted towards the track of the data record carrier.

  The data recording device DRD can further comprise a load unit (not shown) for inserting or removing the data record carrier.

  The electronic device EA includes a processing module PRO and a drive module DRV.

The processing module PRO can have a data encoding module, a control module and a laser power control module connected through a bus (these elements are omitted in the drawing for reasons of clarity). The data encoding module function is to encode and decode data according to a pre-defined recording format. The data encoding module provides signals used for writing marks on the optical record carrier OM and also timing signals. The processing module PRO can receive commands from consumer electronic devices (audio devices, video devices, computers, televisions, etc.). The laser power control module supplies a laser power control signal to the read / write head OH in order to set the read / write power of the laser light source. In general, the laser power control module operates depending on three input signals to control the laser power. The input signals are known as delta signals, threshold signals and alpha signals. The processing module PRO can further be connected to an interface module (not shown). The interface module makes it possible to connect the data recording device DRD with other electronic circuits generally included in consumer electronic equipment. Operation of the processing module requires a clock frequency clk and the core current I _C.

The drive module DRV is coupled to the processing module PRO. The drive module DRV controls the elements of the read / write head OH of the turntable TM, the sled motor SM and the data recording device DRD. More precisely, the driving module DRV, in order to control the rotational frequency of the optical disk OM, supplies a first motor signal S _TM to the turntable motor TM. Driving module DRV, in order to control the scanning of the track position and thus the optical disk OM read / write heads OH, supplies a second motor signal S _SM to the thread motor SM. Driving module DRV is read / write head OH focus, collimate, in order to control the tilt parameter, and supplies a plurality of read / write head signal S _OH to read / write head OH.

  FIG. 2 shows two frequency profiles CAV and (CLV, VLV) corresponding to the rotational frequency of the turntable motor TM as a function of the position of the read / write head on the data record carrier. The rotation frequency is proportional to the angular velocity ω of the turntable motor. These frequency profiles are used for both read and write operations.

  The first frequency profile CAV corresponds to a general operation mode according to the prior art (dotted line).

  The second frequency profile corresponds to the operating mode according to the invention (solid line), ie to a combination of a constant linear velocity part CLV and a variable linear velocity part VLV.

  The first frequency profile CAV is associated with a turntable motor that operates according to a constant angular velocity. The constant angular velocity corresponds to a rotation frequency f of 155 Hz, for example. The first frequency profile CAV gradually changes from the start data transfer rate SSx to the final data transfer rate SFx. The start data transfer rate SSx may correspond to a standardized 6x speed. The final data transfer rate SFx can correspond to standardized 16 times speed. The data transfer rate is increased linearly as a function of radius R from the start data transfer rate SSx to the final data transfer rate SFx. The start data transfer rate SSx is associated with a read / write head arranged at a radius R corresponding to the inner area of the optical disc OM. Here, for example, the radius R is about 0.022 m. The final data transfer rate SFx is associated with a read / write head arranged at a radius R corresponding to the outer area of the optical disc OM. Here, for example, the radius R is about 0.058 m.

  The second frequency profiles CLV and VLV correspond to a turntable motor that operates according to a partial linear velocity. The second frequency profile includes a first portion CLV and a second portion VLV. Along the first part, the data transfer rate gradually changes from the start data transfer rate SSx to the intermediate data transfer rate SCP, and the rotation frequency f decreases. The rotational frequency is decreased substantially linearly along the first portion. As an alternative, other types of reduction profiles can be used, for example log reduction. The start data transfer rate SSx can correspond to a standardized 6 × speed, and the start rotation frequency f1 can be about 155 Hz. The intermediate data transfer rate SCP may be lower than the starting data transfer rate SSx, and the intermediate rotation frequency f2 may be about 75 Hz. The data transfer rate is decreased as a function of radius R from the starting data transfer rate SSx to the intermediate data transfer rate SCP. Along the second part, the data transfer rate gradually changes from the intermediate data transfer rate to the final data transfer rate, and the rotation frequency f increases. The rotational frequency is increased substantially linearly along the second portion. As an alternative, other types of increase profiles can be used, for example an exponential increase. The final data transfer rate SFx can correspond to a standardized 16 × speed, and the final rotation frequency f3 can be about 155 Hz. The data transfer rate is increased from the intermediate data transfer rate SCP to the final data transfer rate SFx. Along the second portion VLV, the laser source power and other write strategy parameters can be changed as a function of the data transfer rate.

  The hatched area PS1 between the first frequency profile and the second frequency profile is proportional to the reduction in power loss of the drive module due to the frequency profile according to the invention.

FIG. 4 shows an alternative example of the frequency profile shown in FIG. The determined position of the read / write head may be adjustable to various positions. Each position corresponds to a specific intermediate data transfer rate / rotation frequency pair. A particular intermediate data rate / rotation frequency pair defines a determined switching point between a constant linear velocity portion CLV and a variable linear velocity portion VLV of the frequency profile according to the present invention. FIG. 4 shows an intermediate data transfer rate / rotation frequency pair of the first SCP ₁ / f 2 ₁ , the second SCP ₂ / f _{2 2} , the third SCP ₃ / f 2 ₃ and the fourth SCP _n / f 2 _n . Four examples of frequency profiles each included are shown.

  The determined switching point can be adjusted as a function of various parameters of the data recorder DRD, for example as a function of the laser temperature, or between the throughput rate (overall data record carrier writing speed) and power loss. An acceptable compromise between can be specified.

  The determined switching point can be adjusted by the processing module and can be made adaptable to the particular consumer electronics application to which the data recording device is coupled (eg, through calibration).

As a first example, if power loss is an important aspect (eg laptop computer applications) and the write duration of the entire data record carrier is less important, the frequency profile minimizes power loss To be adjusted. In this case, the switching point corresponds to the fourth SCP _n / f2 _n intermediate data transfer rate / rotation frequency pair.

As a second example, if a compromise is required between the power loss and the write duration of the entire data record carrier (eg desktop computer application), the frequency profile indicates that the switching point is the first SCP ₁ / f2 is adjusted to correspond to ₁ intermediate data transfer rate / rotational frequency pair.

3, as a function of the position of the read / write heads on the data record carrier, shows two current curves showing the core current I _C of the electronic device EA. The first current curves CAVC1 and CAVC2 correspond to a general operation mode according to the prior art (dotted line). The second current curves CLVC, VLVC correspond to the operation mode according to the present invention (solid line).

  The first current curves CAVC1, CAVC2 are associated with the first frequency profile CAV shown in FIG. The first current curve includes a first current curve portion CAVC1 and a second current curve portion CAVC2.

The first current curve portion CAVC1 is associated with a read / write operation in the inner area of the optical disc OM. In this region, the data transfer rate is low, resulting in a low processing module clock frequency and a low core current. For example, the core current _{I C,} the inner region, i.e. the radius R of 0.022 to 0.034 m, may be about 200mA.

The second current curve portion CAVC2 is associated with a read / write operation outside the inner area of the optical disc OM. Outside the inner region, there is a sudden change in the data transfer rate, resulting in a larger processing module clock frequency and a larger core current. For example, the core current _{I C} is the region of 0.034m to 0.058M, changes suddenly to 260 mA, to increase slightly until 270 mA.

  The second current curves CLVC, VLVC are associated with the second frequency profiles CLV, VLV shown in FIG. The second current curve includes a first current curve portion CLVC and a second current curve portion VLVC.

The first current curve portion CLVC is associated with a reduction in the rotation frequency f (see FIG. 2) and a reduction in the data transfer rate. Thus, the data transfer rate is low, resulting in a low processing module clock frequency. This makes it possible to keep the core current low and constant. For example, the core current _{I C} is the position of the read / write head of the radius R of 0.022m to 0.050 M, may be about 200mA.

The second current curve portion VLVC is associated with a read / write operation in the outer area of the optical disc OM. In the outer region, there is a change in data transfer rate and turntable motor rotation frequency (see FIG. 2), resulting in a higher processing module clock frequency and a higher core current. For example, the core current _{I C} is for the outer region of 0.050m to 0.058M, it may increase from 200mA to 270 mA.

  The hatched region PS2 between the first current curve and the second current curve is proportional to the power loss reduction in the drive module due to the frequency profile according to the invention.

  Although the foregoing description has focused on the application of the method of the present invention to an optical data recording device using a laser, it will be apparent to those skilled in the art that the present invention can also be used in magnetic hard disk drive applications. Will.

  The drawings and their above description are illustrative of the invention and are not limiting.

  Any reference signs in the claims should not be construed as limiting the claim. The word “comprising” does not exclude the presence of other elements than those listed in a claim. An element expressed in the singular does not exclude the presence of a plurality of such elements.

1 is a block diagram schematically and partly showing a data recording device having an electronic device implementing the method according to the invention. FIG. 4 shows two frequency profiles showing the rotation frequency as a function of the position of the read / write head on the data record carrier. 2 shows two curves showing the core current of the electronic device as a function of the position of the read / write head on the data record carrier. FIG. 4 shows an alternative example of a frequency profile showing the rotation frequency as a function of the position of the read / write head on the data record carrier.

Claims (11)

A read / write head for reading / writing data on a data record carrier;
A turntable motor for rotating the data record carrier;
A method of operating a data recording device comprising:
The method includes generating a control signal that varies the rotational frequency as a function of the position of the read / write head on the data record carrier according to a frequency profile that defines the rotational frequency of the turntable motor; The frequency profile includes a first portion followed by a second portion, during which the rotational frequency is reduced from a start frequency to an intermediate frequency, and during the second portion, the A method in which the rotational frequency is increased from the intermediate frequency to the final frequency.   The method of claim 1, wherein the rotational frequency is decreased substantially linearly along the first portion.   The method of claim 1, wherein the rotational frequency is increased substantially linearly along the second portion.   The method according to claim 1, wherein the intermediate frequency corresponds to a determined position of the read / write head on the data record carrier.   The method of claim 4, wherein the determined position of the read / write head is adjustable.   6. A method according to claim 4 or claim 5, wherein the determined position of the read / write head corresponds to an outer region of the data record carrier. A read / write head for reading / writing data on a data record carrier;
A turntable motor for rotating the data record carrier;
An electronic device that is coupled to the turntable motor and generates a control signal that changes the rotational frequency according to a frequency profile that defines the rotational frequency of the turntable motor as a function of the position of a read / write head on the data record carrier The frequency profile includes a first portion followed by a second portion, during which the rotational frequency is reduced from a start frequency to an intermediate frequency, and the second portion During which the rotational frequency is increased from the intermediate frequency to a final frequency;
A data recording device.   The data recording apparatus according to claim 7, wherein the electronic device generates the control signal such that a core current in the electronic device is kept constant during the first portion.   8. A data recording apparatus according to claim 7, wherein the rotational frequency is decreased substantially linearly along the first portion.   8. A data recording apparatus according to claim 7, wherein the rotational frequency is increased substantially linearly along the second portion.   A computer program for a data recording device, comprising a set of instructions that, when loaded into the data recording device, causes the data recording device to perform the various steps of the method according to any one of claims 1 to 6. .

Images