KR100255208B1 - Motor control device and method for b.c.a. code reproducing - Google Patents

Abstract

PURPOSE: An apparatus for controlling a motor for BCA(Burst Cutting Area) code regenerating is provided to CAV(Constant Angular Velocity) control the optical disk driving motor, and to count BCA code pulse periods with a crystal clock to distribute BCA codes. Therefore, the BCA codes are securely regenerated regardless of a jitter of the motor or a defect. CONSTITUTION: An optical disk(10) mounted on a driving axis of a spindle motor(16) is rotated at a CLV(Constant Linear Velocity) or a CAV(Constant Angular Velocity) by a disk driving controller. An RF(Radio Frequency) signal processor amplifies signals read in an optical pickup(12) and shapes waveforms of the signals, then transmits the signals to a PLL(Phase Locked Loop) & pulse width recognizer(18) and the disk driving controller. The PLL & pulse width recognizer(18) generates a clock(PCLK) synchronized with signals regenerated from the optical disk(10), and transmits the clock(PCLK) to the disk driving controller. The PLL & pulse width recognizer(18) counts pulse widths of BCA(Burst Cutting Area) codes inputted from the RF signal processor with a crystal clock(XCLK), then outputs data according to counting results to a BCA code regenerating circuit(22). A disk driving controller(26) is composed of a CLV circuit and a CAV circuit for controlling the spindle motor(16). The CLV/CAV circuits are selectively driven according to mode selecting signal CLV/CAV inputted from a microprocessor(24), respectively. The microprocessor builds a memory storing a control program therein, and controls the entire operation of a DVD(Digital Video Disk)-ROM drive.

Description

Motor control device and method for regenerating BCA code

The present invention relates to an optical disc reproducing apparatus such as a DVD-ROM drive and a CD-ROM drive. More particularly, the present invention relates to a motor control apparatus and a method for reproducing a BCA code while controlling the motor so as to stably reproduce the BCA code.

The BCA (Burst Cutting Area) code refers to an optical disc license ID code and refers to a code that must be played when a disc such as a DVD-ROM or CD-ROM is accessed. The BCA code is a lead-in code for an optical disc. It is generally located at the innermost circumference of the area. Hereinafter, an optical disc control method for BCA code reproduction will be described with reference to FIG. 1.

Fig. 1 shows a schematic block diagram of a DVD-ROM drive for explaining the BCA code reproduction process. In FIG. 1, the optical disc 10 mounted on the drive shaft of the spindle motor 16 is rotated at a predetermined speed by the disc drive control unit 20. The optical pickup 12 irradiates a laser light for reproducing data, receives the reflected light, converts the reflected light into an analog high frequency (RF) signal, and outputs the signal to an RF signal processor (not shown). The RF signal processor amplifies the signal read out from the optical pickup 12 to a level sufficient to process the next stage, and after shaping the waveform, PLL (Phase Locked Loop) & pulse width detection unit 18 And to the disk drive control unit 20. The PLL & pulse width detecting unit 18 is a phase comparator, divider, etc. generates a clock PCLK synchronized with the signal reproduced from the optical disc 12 and outputs the generated clock PCLK to the disc driving controller 20. PCLK represents a comparison clock for CLV. The disk drive control unit 20 outputs a motor control signal for CLV control of the optical disk 12 in consideration of the frequency servo, phase servo, and the like according to the frame synchronization signal provided from the synchronous detection unit (not shown). The BCA code reproducing circuit 22 regenerates the BCA code in accordance with the clock CLK and data input from the PLL & pulse width detecting unit 18. The data refers to the pulse width data of the BCA code counted by the PLL & pulse width detection unit 18. The microprocessor 24 outputs a control signal for focusing and tracking control of the optical pickup 12, and simultaneously controls the sled feed motor 14 to control the optical pickup 12 to the optical disk 10. Transfer from the plane.

In the DVD-ROM drive having the above-described configuration, the following problem occurs when the BCA code is reproduced. First, when the optical pickup 12 jumps to the BCA code area under the control of the microprocessor 24 during the play-in of the lead-in area, the rotation of the optical disc 12 is maintained in an unstable state immediately after the jump. ) Rotation control becomes impossible. The reason is that the PLL control cannot be normally performed because there is no reference signal (data SYNC pattern) for rotating control of the optical disc 12 in the BCA code. Therefore, it is difficult to expect stable BCA code reproduction. On the other hand, even if the optical pickup 12 is jumped to the BCA code region and then PWM (Pulse Width Modulation) control is performed for stable rotation control of the optical disk 12, since the optical loop 12 is an open loop, the optical disk 12 is rotated. The problem is that the speed is saturated to one side (acceleration or deceleration).

Accordingly, an object of the present invention is to provide a motor control apparatus and method for reproducing a BCA code while controlling an optical disc drive motor to safely reproduce a BCA code recorded at a predetermined position on an optical disk surface.

It is still another object of the present invention to provide a motor control apparatus and method for safely reproducing BCA codes even when there is jitter in an optical disk drive motor or defects in a BCA code area during BCA code reproduction.

In the present invention for achieving the above object, there is provided an optical disc reproducing apparatus comprising a motor for driving an optical recording medium and a reproducing circuit for reproducing a BCA code read out from the optical recording medium.

An optical recording medium driving control unit capable of rotating the optical recording medium at a predetermined speed or at a regular angle speed according to a mode selection signal;

A control unit for setting the mode selection signal so that the optical recording medium is rotated at a right angle speed when the BCA code recorded at a predetermined position on the surface of the optical recording medium is rotated;

And a pulse width sensing unit configured to count the pulse period of the BCA code inputted at the time of rotation of the optical recording medium by the crystal clock to detect the pulse period of the BCA code.

1 is a schematic block diagram of a DVD-ROM drive for explaining a BCA code reproduction process.

2 is a schematic block diagram of a DVD-ROM drive including a motor control apparatus according to an embodiment of the present invention.

3 is a circuit diagram for explaining the CAV circuit operation of the disk drive control section 26 according to the embodiment of the present invention.

Hereinafter, a motor control apparatus and a control method thereof according to an embodiment of the present invention will be described with reference to the accompanying drawings.

Figure 2 shows a schematic block diagram of a DVD-ROM drive including a motor control apparatus according to an embodiment of the present invention. Referring to FIG. 2, the optical disc 10 mounted on the drive shaft of the spindle motor 16 is rotated by the disc drive control unit 20 at a constant speed or a regular angle speed. The optical pickup 12 irradiates a laser light for reproducing data, receives the reflected light, converts the reflected light into an analog high frequency (RF) signal, and outputs the signal to an RF signal processor (not shown). The RF signal processor amplifies the signal read out from the optical pickup 12 to a level sufficient to process the next stage, and after shaping the waveform, PLL (Phase Locked Loop) & pulse width detection unit 18 And to the disk drive control unit 20. The PLL & pulse width detecting unit 18 includes a phase comparator, a counter, a divider, and the like, and generates a clock PCLK synchronized with the signal reproduced from the optical disc 12 and outputs the generated clock PCLK to the disc driving controller 20. In addition, the PLL & pulse width detecting unit 18 counts the pulse width of the BCA code inputted from the RF signal processor by the crystal clock XCLK, and counts the data according to the counting results (T, 2T, 3T, 4T) of the BCA code reproducing circuit ( 22). The disk drive control section 26 is composed of a CLV circuit and a CAV circuit for controlling the spindle motor 16 for driving the optical disk 12. Each of the CLV circuit and the CAV circuit is selectively driven in accordance with the mode selection signal CLV / CAV input from the microprocessor 24. The microprocessor 24 controls the overall operation of the DVD-ROM drive by incorporating a memory in which a control program according to an exemplary embodiment of the present invention is stored.

3 is a circuit diagram for explaining the CAV circuit operation of the disc drive control unit 26 according to the embodiment of the present invention. Referring to FIG. 3, the CAV circuit of the disc drive control unit 26 counts a frequency division circuit 2 (32) for pre-specifying the crystal clock XCLK generated by the crystal oscillator and a signal FG for monitoring the motor rotational speed for a predetermined period. A counter 34 and a counter value comparator 38 for outputting a motor control signal 1 at an angular speed according to a comparison result by comparing the output signal of the frequency divider circuit 32 with the counter counted by the counter 34; The motor of the angular velocity according to the result is compared between the frequency division circuit 1 (30) for dividing the motor rotation period monitor signal FG, the output signal of the frequency division circuit 1 (30) and the output signal of the frequency division circuit 2 (32). A phase comparator 36 for outputting a control signal 2 is provided.

개의 크리스탈 클럭 XCLK이 존재하게 된다. 따라서 분주회로2(32)에서 크리스탈 클럭 XCLK를 n분주하여 출력되는 클럭을 기준클럭으로 하고 위상비교기(36)에서 상기 기준클럭과 모터 회전주기 모니터 신호(FG)의 위상을 비교하여 그 에러신호를 모터제어신호1로 출력한다. 따라서 마이크로 프로세서(24)는 광 디스크(12) 최초 재생시 디스크 구동 제어부(26)의 CAV회로가 선택되도록 모드선택신호 CLV/CAV를 세팅하면 광 디스크(12)로부터 입력되는 BCA코드에 관계없이 모터 회전주기 모니터 신호(FG)만으로 광 디스크(12)의 회전을 제어할 수 있다. 그리고 불필요한 점프를 수행하지 않아도 됨으로 BCA코드 재생시 안정되게 광 디스크(12)를 회전제어할 수 있다.When the BCA code region is reproduced, the BCA code reproduction process described above is explained below. First, the rotation speed of the optical disc 12 is assumed to be R [Hz] at the innermost circumference, and M per revolution of the optical disc 12 is assumed. Assuming that two FG signals are output, the motor rotation period monitor signal FG becomes RM [Hz]. If the crystal clock XCLK is selected by n times RM [Hz] and the basic period of the BCA code is T, the basic period T of the BCA code is

There are four crystal clocks XCLK. Therefore, the clock output by dividing n by the crystal clock XCLK in the division circuit 2 (32) is used as the reference clock, and the phase comparator 36 compares the phase of the reference clock and the motor rotation period monitor signal FG to obtain the error signal. Output by motor control signal 1. Therefore, when the microprocessor 24 sets the mode selection signal CLV / CAV so that the CAV circuit of the disc drive control unit 26 is selected when the optical disc 12 is first reproduced, the microprocessor 24 sets the motor regardless of the BCA code input from the optical disc 12. The rotation of the optical disc 12 can be controlled only by the rotation period monitor signal FG. Since unnecessary jumps are not performed, the optical disk 12 can be stably rotated during BCA code reproduction.

On the other hand, in the embodiment of the present invention without using the data PLL when reproducing the BCA code, as described above, the pulse period (if the basic period is T) of the BCA code is counted by the crystal clock XCLK, and the counting results are shown in Table 1 below. Based on this, it divides into 1T-4T.

Pulse period 1T 2T 3T 4T Counting value A-α-A + α 2A-α ~ 2A + α 3A-α to 3A + α 4A-α to 4A + α

In Table 1, the crystal clock XCLK is RMn [Hz] as described above, α represents a range of counted errors, and A represents the number of XCLKs present in the basic period T. As shown in Table 1, since 1T to 4T are distinguished within a range of ± α, the optical disk 12 has strong resistance to scratches and jitter of the spindle motor 16. Since the BCA code is different from the modulation type of the main data, that is, there is no sync pattern, the CAV control of the optical disc 12 during BCA code reproduction and the pulse period of the BCA code are counted by the crystal clock XCLK to distinguish the data. This makes it possible to reproduce stable BCA codes.

As described above, the present invention has the advantage that the BCA code can be stably reproduced by CAV control of the optical disk drive motor during BCA code reproduction. In addition, the BCA code is divided into BCA codes by counting the BCA code pulse periods with a crystal clock, so that the BCA codes can be stably reproduced regardless of the jitter of the optical disk drive motor or the presence or absence of defects in the BCA code area.

Claims (4)

An optical disc reproducing apparatus having a motor for driving an optical recording medium and a reproducing circuit for reproducing a BCA code read out from the optical recording medium, An optical recording medium driving control unit capable of rotating the optical recording medium at a predetermined speed or at a regular angle speed according to a mode selection signal; A control unit for setting the mode selection signal so that the optical recording medium is rotated at a right angle speed when the BCA code recorded at a predetermined position on the surface of the optical recording medium is rotated; And a pulse width sensing unit configured to count the pulse period of the BCA code inputted at the time of rotation of the optical recording medium by a crystal clock to detect the pulse period of the BCA code. The optical recording medium driving control unit according to claim 1; and comparing the phase of the n-divided crystal clock with the rotation period monitor signal (FG) of the motor and outputting the error signal as a motor control signal. The motor control apparatus according to claim 1, wherein the pulse width detecting unit detects the pulse period of the BCA code counted by the crystal clock in a range of 1T to 4T (T: basic pulse period) within a tolerance range. . A motor for driving an optical recording medium, a reproducing circuit for reproducing the BCA code read out from the optical recording medium, and an optical light capable of rotating the optical recording medium at a predetermined speed or at a regular angle speed according to a mode selection signal. An optical disk reproducing apparatus comprising: a recording medium driving control unit; and a pulse width detecting unit for counting a pulse period of a BCA code inputted at the time of rotation of the optical recording medium by a crystal clock to detect a pulse period of the BCA code. And setting a mode selection signal for rotating the optical recording medium at a right angle speed so that the BCA code pulse width read from the optical recording medium is counted by a crystal clock when the BCA code is reproduced and outputted to the optical recording medium driving controller. Motor control method.

Images