KR19990075423A - Disc rotation speed control device and method for DVD-RAM disc playback in optical disc playback drive - Google Patents

Abstract

The technical field to which the invention described in the claims belongs.

An optical disc playback drive.

B. Technical problem to be solved

An apparatus and method for controlling the rotational speed of a spindle motor during playback of a DVD-RAM disc in an optical disc reproducing drive.

C. Summary of the Solution

In the conventional optical disc reproducing drive, a wobble signal detection unit is provided, and the detection period of the header signal is measured in the header signal area when the DVD-RAM disc is reproduced by the zone-CLV server method and compared with a preset header signal reference period. After measuring the detection period of the wobble signal and comparing it with a preset wobble signal reference period, the error reflected by the constant ratio by reflecting the error value according to the header signal detection period and the error value according to the wobble signal detection period as a constant ratio It is characterized by controlling the rotation speed of the spindle motor based on the value.

D. Significant Uses of the Invention

Used to play DVD-RAM discs in an optical disc drive.

Description

Disc rotation speed control device and method for DVD-RAM disc playback in optical disc playback drive

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc reproducing drive, and more particularly, to an apparatus and method for controlling the rotational speed of a spindle motor in an optical disc reproducing drive.

In the conventional optical disc reproducing drive, the rotational speed of the spindle motor is controlled by the CLV (Constant Linear Velocity) servo method. CLV servo method refers to the difference generated by comparing the count value with a predetermined value after counting the period of the synchronous signal detected from the signal reproduced through the optical pickup by the spindle. Is a method of controlling the rotational speed of the spindle motor by converting and outputting it into the control signal of the spindle motor. However, when the rotation speed of the spindle motor is controlled by adopting the CLV servo method, it becomes a problem in high speed regeneration. This is because the spindle motor is not controlled by the instantaneous control signal because the rotational inertia of the spindle motor is large during high speed regeneration. To solve this problem, CAV (Constant Angular Velocity) servo method has emerged. The CAV servo method does not use the synchronous signal detected from the signal reproduced through the optical pickup by the spindle motor controller, but detects the rotation period of the spindle motor and outputs a control signal directly to the spindle motor to improve the rotation speed of the spindle motor. It's a way of control. Therefore, the CAV servo method has a configuration in which a circuit portion for detecting the rotation period of the spindle motor is added to the CLV servo method.

On the other hand, a DVD-RAM (hereinafter referred to as a "DVD-RAM") disk, which is an example of an optical disk, cannot be reproduced by a drive employing the above-described CLV servo method or CAV servo method, but employs only the zoned-CLV servo method. Can only be played on the drive. This is because the header information is recorded at regular intervals on the data recording surface when the DVD-RAM disc is produced. Accordingly, in the zone-CLV servo system, the spindle motor is controlled to reproduce predetermined data so that the detection period of the header signal containing the header information is constant. In general, there is 17 header information per track in the inner circumference of a DVD-RAM disc, and 42 header information per track in the outer circumference. Therefore, the rotation speed of the spindle motor when the inner peripheral portion of the DVD-RAM disc is played is higher than the speed during the outer peripheral portion.

However, the detection period of the header signal is about 26 times longer than the detection period of the synchronization signal detected by the conventional CLV servo method. Therefore, the Zone-CLV servo system, which is adopted for DVD-RAM disc reproduction and controls the spindle motor by detecting the period of the header signal recorded on the DVD-RAM disc, has no problem at high speed playback, but at low speed playback. There was a problem that it is difficult to precisely control the rotation speed of the.

As described above, in the conventional optical disc reproducing drive, the zone-CLV servo system which controls the spindle motor by detecting the period of the header signal when the DVD-RAM disc is reproduced, is because the detection period of the header signal is considerably longer than that of the synchronization signal. At low speeds, it was difficult to precisely control the rotational speed of the spindle motor.

Accordingly, an object of the present invention is to provide a rotation speed control apparatus and method for a spindle motor capable of precisely controlling the rotation speed of the spindle motor even when the DVD-RAM disc is played at a low speed.

1 is a block diagram of an optical disc reproducing drive according to an embodiment of the present invention;

2 is a flowchart illustrating a process of controlling a rotational speed of a disk during playback of a DVD-RAM disk in an optical disk playback drive according to an embodiment of the present invention.

In order to achieve the above object, the present invention includes a wobble signal detection unit in a conventional optical disc reproducing drive and measures a detection period of a header signal in a header signal area when reproducing a DVD-RAM disc using a zone-CLV server method. Compared with the reference period, and in the wobble signal area, the detection period of the wobble signal is measured and compared with a preset wobble signal reference period, and then the error value according to the header signal detection period and the error value according to the wobble signal detection period are constant. It is characterized by controlling the rotational speed of the spindle motor on the basis of the error value reflected by the predetermined ratio reflected by the ratio.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Many specific details are set forth in the following description and in the accompanying drawings to provide a more general understanding of the invention. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

1 is a block diagram of an optical disc reproducing drive according to an embodiment of the present invention. Referring to FIG. 1, the optical pick-up 102 optically picks up information recorded on the optical disc 100 and generates an RF signal, which is converted into an electrical signal, to generate an RF signal. Output to the amplifier 106. The optical pickup 102 is driven by a tracking actuator for tracking servo and a focusing actuator for focus servo. The spindle motor 104 rotates the mounted or loaded optical disc 100 in a CLV method, a CAV method, or a zone-CLV method by driving by the spindle motor driving signal output from the spindle motor driver 120. The sled feed motor 126 is driven by a sled feed servo control signal input from the servo driver 116 to transfer the optical pickup 102 in the optical pickup moving axis direction on the optical disk 100 plane. Let's do it. Meanwhile, the RF amplifier 106 amplifies the RF signal output from the optical pickup 102, removes the noise and distortion of the amplified signal by the waveform equalization circuit, and digitally synchronizes the waveform-shaped EFM / ESM signal. The data is transmitted to the DSP (Digital Signal Processor) 112, which is a data processing unit, through a loop locked loop (hereinafter, referred to as a "PLL unit"). The PLL unit 110 is a phase comparator, and includes a voltage controlled oscillator and a divider to generate a clock synchronized with the signal reproduced from the optical disc 100. The RF amplifier 106 generates a focus error detection circuit and a tracking error detection circuit, and generates signals for the focus servo and the tracking servo, that is, the focus error signal and the tracking error signal, and outputs them to the servo processor 118. The servo processor 118 digitally processes the focus error signal and the tracking error signal output from the RF amplifier 106 to compensate for the error of the focus error signal and the tracking error signal. The sled feed servo control signal is output to the servo driver 116. The servo driver 116 generates and outputs a driving signal according to a focus servo control signal, a tracking servo control signal, and a sled feed servo control signal output from the servo processor 118. The header area display unit 108 detects the start point of the header area because the waveform of the RF signal is different in the header area, and displays a flag at a specific level in the portion corresponding to the header area to detect the wobble period in the DSP 112. And an N division block. The flag indicating the header area is used so that the wobble period detecting unit and the N division block which will be described later do not measure the period of the wobble signal in the header area. The DSP 112, which is a data processing unit, is divided into a DVD decoder section for processing data reproduced from a DVD series optical disc and a CD decoder section for processing data reproduced from a CD series optical disc as a system decoder. In FIG. 1, only a DVD / CD decoder, a sync period detector, a wobble period detector, an N divider, and a header period detector are illustrated for clarity. The DVD / CD decoder, which is a component in the DSP 112, demodulates the data stream EFM / ESM input from the RF amplifier 106, and corrects and descrambles the data stream EFM / ESM. The header period detector, which is another component in the DSP 112, detects a header signal from a data stream ESM input during DVD-RAM disc playback, measures the period of the header signal, and outputs the header signal to the spindle motor controller 122. do. In addition, the wobble period detector and the N divider detect a wobble signal from the data stream ESM input during reproduction of the DVD-RAM disc, measure the period of the wobble signal, and divide the N signal again to spin the period value of the N divided wobble signal. Output to the motor controller. The period of the wobble signal is generally about 8 times faster than the period of the synchronization signal. Therefore, this may be used as it is, but in practice, since the control signal does not have to be generated as soon as possible, the embodiment of the present invention divides the period of the wobble signal by eight to make the period of the wobble signal equal to the period of the synchronization signal. Explain. In addition, the synchronization cycle detection unit, which is another component in the DSP 112, detects a synchronization signal from the data stream EFM / ESM input during CD-ROM and DVD-ROM playback, respectively, and measures the period of the synchronization signal to control the spindle motor. Output to the 122 and the microcomputer 124. Although not shown, the DSP 112 is connected to a memory used for error correction. The interface unit 114 is an AT Attachment Packet Interface (ATAPI), which is connected to the DSP 112 and the microcomputer 124 and interfaces various control signals and data transmitted between the host and the optical disc reproducing drive. The microcomputer 124 controls the overall operation of the drive by including a ROM in which a control program according to an embodiment of the present invention is stored and a RAM for temporarily storing data generated during a control operation. For example, the microcomputer 124 determines the type of the optical disc 100 through the focus error signal input from the servo processor 118, generates an optical disc determination signal accordingly, and outputs it to the spindle motor controller 122. The spindle motor controller 122 includes a memory in which a reference cycle table corresponding to reference cycles for each speed is stored for the CLV servo method, the CAV servo method, and the John-CLV servo method, and the microcomputer 124 and the DSP 112. Generates and outputs a spindle control signal for controlling the rotational speed of the spindle motor 104 in accordance with the signal input from. That is, the spindle motor control unit 122 initially drives the spindle motor 104 in response to the initial drive signal input from the microcomputer 124, and according to the optical disc discrimination signal input from the microcomputer 124, three servo methods ( Set one of the following: CLV, CAV, or Zone-CLV. The spindle motor controller 122 reads the reference period corresponding to the double speed setting signal input from the microcomputer 124 from the table and compares it with one of the period of the header signal, the period of the synchronization signal, and the period of the rotation detection signal. Outputs the spindle motor rotation speed control signal to compensate for error values. In particular, in the embodiment of the present invention, after reproducing the DVD-RAM disc, the error value comparing the period of the header signal and the error value comparing the period of the wobble signal are obtained, and then the appropriate proportional value is set for each error value. The spindle motor rotational speed control signal for controlling the spindle motor more precisely by using all detected periods is output to the spindle motor driver 120. The spindle motor driving unit 120 compares the voltage level of the spindle motor rotational speed control signal input from the spindle motor control unit 122 with a reference voltage level to adjust the spindle motor driving signal for increasing or decreasing the rotational speed of the spindle motor 104. Output

FIG. 2 illustrates a method of controlling a spindle motor by using a cycle of two signals by detecting a cycle of a header signal and a cycle of a wobble signal when a DVD-RAM disc is played in the optical disc playback drive of FIG. 1 according to an embodiment of the present invention. A process flow diagram is shown. The operation according to the flowchart of FIG. 2 is performed by the microcomputer 124 of FIG. 1. An embodiment of the present invention will now be described in detail with reference to FIGS. 1 and 2.

First, the microcomputer 124 checks whether the optical disk 100 is loaded on the tray in step 200 and loaded into the drive. Since the loading completion inspection process of the optical disc 100 is already known technology, a detailed description thereof will be omitted. At this time, if the optical disk 100 is mounted on the tray and the loading is completed in the drive, the microcomputer 124 proceeds to step 202 to transmit a drive signal for initial driving the spindle motor 104 to the spindle motor controller 122. Output Accordingly, the spindle motor controller 122 drives the spindle motor 120 according to the initial driving signal. The microcomputer 124 proceeds to step 204 to perform a subroutine for determining the type of the optical disc 100 mounted on the tray. The optical disc discrimination subroutine can be confirmed by checking the amplitude level of the S-curve generated during focusing servo control, which is also a well-known technique, and thus a detailed description thereof will be omitted. If the type of the optical disc 100 mounted on the tray is determined as a result of performing the optical disc determination subroutine, the microcomputer 124 proceeds to step 206 to determine whether the optical disc 100 is a DVD-RAM disc. . In this case, if the optical disc 100 is not a DVD-RAM disc, the microcomputer 124 proceeds to step 208 in response to a key input by a user according to the type of the optical disc 100 determined in step 204. Perform the action.

On the contrary, when the optical disc 100 is a DVD-RAM disc in step 206, the microcomputer 124 proceeds to step 210 and outputs an optical disc determination signal indicating the type of the optical disc 100 determined by the spindle motor controller. 122). Accordingly, the spindle motor control unit 122 recognizes that the input optical disk 100 is a DVD-RAM disk, and sets the servo method to the zone-CLV servo method. The microcomputer 124 proceeds to step 212 and checks whether the microcomputer 124 is in the playback mode. The reproduction mode refers to a mode in which data of the DVD-RAM disc is reproduced when there is a key operation for reading information on the DVD-RAM disc by a user. In the above description, a DVD-RAM disk is assumed to be an uninitialized disk for convenience of description. An uninitialized DVD-RAM disk refers to a disk in which data is not recorded in the record area and only data is recorded in the header area. Therefore, conventionally, the header cycle or wobble cycle should be used for the rotation control of the DVD-RAM disc that has not been initialized. The header cycle is considerably longer than the period of the normal synchronization signal, so that the rotation control is difficult at low speed. There was a problem as described above. Referring back to the flowchart according to the embodiment of the present invention, if the mode is to play the DVD-RAM disc in step 212, the microcomputer 124 proceeds to step 214 and is inputted from the DVD-RAM disc. It is checked whether the RF signal is a signal in the header area or a signal in the wobble area. In this case, if the input signal is a signal of the header region, the microcomputer 124 proceeds to step 216 to detect the header signal, and to measure the period of the header signal in step 218. The microcomputer 124 proceeds to step 220 and compares the detection period of the header signal measured in step 218 with the reference period of the header signal stored in advance and calculates an error value. At this time, in calculating the error value, a positive value is taken if the detection period value is larger than the reference period value, and a negative value is taken if the detection period value is smaller than the reference period value. In operation 228, the microcomputer 124 multiplies the calculated error value of the header signal by a preset proportional value N1 to reduce the error value at a constant ratio. In the above, the microcomputer 124 differs from the error value of the header signal and the wobble signal generated during reproduction, unlike the conventional control of the rotational speed of the spindle motor only for the error value of a specific signal of the header signal or the wobble signal. In order to reflect both, multiply the detection period error value of each signal by a proper proportional value, and add it again to calculate a new error value reflecting both the error value of the header signal and the wobble signal and to control the rotational speed of the spindle motor accordingly. do. At this time, the reflectance ratio of the error value of the header signal detection period, that is, the proportional value N1, continues to be lowered. This means that the error value according to the header signal detection period is important in the header area. This is because the importance of the error value decreases.

On the contrary, if the signal input in step 214 is the signal of the wobble region, the microcomputer 124 proceeds to step 222 to detect the wobble signal and measures the period of the wobble signal in step 224. The period detection of the wobble signal is performed by the wobble period detection unit of FIG. 1, wherein the wobble period detection unit recognizes a header area display input by being flagged by a header level display unit 108 of FIG. The wobble signal can be easily detected, and the wobble period detection operation is stopped when the display of the header region is recognized. Next, the microcomputer 124 proceeds to step 226 and compares the detection period of the wobble signal measured in step 224 with the reference period of the wobble signal stored in advance and calculates an error value. At this time, the error value takes a positive value when the detection period value is larger than the reference period value like the header signal, and a negative value when the error value is smaller. The microcomputer 124 proceeds to step 230 and multiplies the calculated error value of the wobble signal by a preset proportional value N2 to reduce the error value to a predetermined ratio. In operation 232, the microcomputer 124 adds the error value of the header signal detection period multiplied by the proportional value N1 and the error value of the wobble signal detection period multiplied by the proportional value N2. After calculating a new error value reflecting both the detection period error values of the signal and the wobble signal, the process proceeds to step 234 to determine whether the new error value calculated in step 232 is a positive value or a negative value. Check if it is. At this time, if the error value calculated in step (232) is a positive value (+), this indicates that the rotation speed of the disk is slow, so the microcomputer 124 proceeds to step (236) through the spindle motor controller 122. A control signal for rapidly rotating the rotation of the spindle motor 104 is output to the spindle motor driver 120. Accordingly, the spindle motor driver 120 increases the rotational speed of the spindle motor 120 by compensating for the error value. On the contrary, if the error value is negative (-) in the step 234, this indicates that the rotation speed of the disk is high, and thus the microcomputer 124 proceeds to the step 238 and the spindle through the spindle motor controller 122. The control signal for slowly rotating the rotation of the motor 104 is output to the spindle motor driver 120. Accordingly, the spindle motor driver 120 reduces the rotational speed of the spindle motor 104 by compensating for the error value. The microcomputer 124 proceeds to step 240 to check whether the playback mode is released. The release of the play mode means a mode of stopping the play of the DVD-RAM disc when there is a key operation for stopping the user from reading information on the DVD-RAM disc. At this time, if the playback mode is not stopped in step 240, the microcomputer 124 returns to step 214 to perform steps 214 to 240 again. On the contrary, when the playback mode is stopped in step 240, the microcomputer 124 ends the operation of reading information from the DVD-RAM disk.

Therefore, the disk rotation is performed by controlling the rotation of the spindle motor according to the new error value reflecting the detection period error value of the header signal detected in the header signal area and the detection period error value of the wobble signal detected in the wobble signal area at an appropriate ratio. Even when the speed is low, precise rotation control of the spindle motor is possible.

As described above, according to the present invention, when the DVD-RAM disc is reproduced in the optical disc reproducing drive, the detection period error value of the header signal and the detection period error value of the wobble signal are reflected at an appropriate ratio to rotate the spindle motor using the newly calculated error value. By controlling the speed, even when the rotational speed of the disk is low, the spindle motor has an advantage of precise rotation control.

Claims (5)

An apparatus for controlling a disc rotation speed when playing a DVD-RAM disc in an optical disc reproducing drive, A header region display unit for displaying a region where a header signal is located from a RF signal reproduced from the DVD-RAM disk and inputted when the DVD-RAM disk is played with a flag having a specific level value; Wobble period detection and N division unit for recognizing the header area from the RF signal input through the header area display unit and detecting and dividing the period of the wobble signal existing in a section other than the header area, and N division unit, and the DVD-RAM disk A data processing unit including a header period detection unit for detecting a period of the header signal from an RF signal reproduced and inputted from The optical disc mounted on the optical disc reproducing drive is discriminated, and an optical disc discrimination signal is output according to the optical disc reproducing drive. In the wobble area, the detection period of the N divided wobble signal detected by the wobble period and the N division unit and the preset wobble signal An error value is calculated by comparison with a reference period, multiplied by a proportional value (N1), and in the header area, a comparison between the detection period of the header signal detected by the header period detection unit and the reference period of the preset header signal is performed. A microcomputer that calculates an error value and multiplies the proportional value (N2), adds two error values multiplied by the proportional value, and outputs the result; Recognizing that the optical disk is the DVD-RAM disk from the optical disk discrimination signal output from the microcomputer, the servo system for reproducing the DVD-RAM disk is set among the plurality of servo methods provided for controlling the rotational speed of the spindle motor. A spindle motor controller for outputting a spindle motor rotational speed control signal for compensating the rotational speed of the spindle motor according to the error value input from the microcomputer; When the rotational speed control signal is received from the spindle motor controller, the spindle motor driving signal corresponding to the rotational speed control signal is generated to generate the spindle motor driving unit for driving the spindle motor corresponding to the rotational speed control signal. Disk rotation speed control device when playing DVD-RAM disc in the optical disc playback drive. The apparatus of claim 1, wherein the servo method for reproducing the DVD-RAM disc is a zone-CLV servo method. The disk rotation of the DVD-RAM disk in the optical disk reproducing drive of claim 1, wherein the wobble period detecting unit and the N dividing unit detect the period of the wobble signal and divide the detected wobble signal period by eight. Speed control. A method of controlling a disc rotation speed when playing a DVD-RAM disc in an optical disc playback drive, Checking whether the RF signal reproduced and inputted from the DVD-RAM disk is a header signal located in a header area or a wobble signal located in a wobble area; If the signal is the header signal located in the header area, detecting the period of the header signal and comparing the period with a reference period of a preset header signal; If the detection period of the header signal is greater than the reference period as a result of the comparison, calculating a positive error value and calculating a negative error value and multiplying by a predetermined proportional value (N1); If the signal is the wobble signal located in the wobble region, detecting the period of the wobble signal and comparing the wobble signal with a reference period of a preset wobble signal; If the detection period of the wobble signal is greater than the reference period as a result of the comparison, the step of calculating a positive error value, and if it is small to calculate a negative error value and multiplies a predetermined proportional value (N2), And controlling the rotational speed of the spindle motor in accordance with the newly generated error value after adding the two error values. The process of claim 4, wherein the controlling of the rotational speed of the spindle motor comprises: Controlling to increase the rotational speed of the spindle motor if the value obtained by adding two error values reduced by the predetermined ratio is a positive value; And controlling the rotational speed of the spindle motor to decrease the rotational speed of the spindle motor if the two error values are negative.