KR19980074767A - Spindle motor of optical disk driver High-speed rotation control device - Google Patents

Abstract

The spindle motor high-speed rotation control apparatus of the present optical disk driver includes a synchronization detecting section for detecting synchronization from a signal read out from the optical disk and demodulated, a counter for counting the detected synchronization at a predetermined clock, A rotation control signal generation unit for generating a signal for controlling a rotation speed of the rotation control signal generation unit; and a determination unit for determining whether or not the number of synchronized counts counted by the counter is within a predetermined range, And a judging unit for judging whether or not the image is displayed.

Description

Spindle motor of optical disk driver High-speed rotation control device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a spindle motor in an optical disc driver, and more particularly to an apparatus for reducing an overhead during high-speed rotation of a spindle motor.

The optical disc driver includes a compact disc-read only memory (CD-ROM) driver and a digital video disc-read only memory (DVD-ROM) have. The DVD-ROM driver is a device that runs a DVD-ROM and also runs a CD-ROM and is connected to a host computer. This DVD-ROM driver basically includes the functions of a DVD player and also reads data. In such an optical disc driver, a spindle motor is used to rotate the optical disc.

When a disc is driven by a Constant Linear Velocity (CLV) method, synchronization is detected among picked-up signals and the rotation of the spindle motor is controlled based on the detected synchronism. Therefore, according to this method, the data output time is constant for the entire area of the disc.

1 is a view schematically showing a configuration of a DVD-ROM driver using a spindle motor.

When the microcomputer 240 receives the DVD-ROM disc reproduction command, the spindle motor rotation control unit 250 outputs the rotation control signal until the period of the synchronization signal input from the synchronization detection unit 230 reaches a desired speed. The spindle motor 160 starts rotating at a certain speed. In the optical pickup having the head 120, information of the DVD-ROM disc 100 is converted into analog high-frequency (RF) signals and output. The RF signal is amplified to a predetermined level by the RF amplifier 200 and transmitted to a digital phase-locked loop (PLL) 210. The PLL 210 includes a phase comparator circuit, a voltage-controlled oscillator, and a frequency divider, and generates a clock synchronized with a signal reproduced from the DVD-ROM disc 100.

When the rotation speed of the spindle motor 160 is stabilized or stabilized, the ESM demodulator 220 demodulates the ESM from this point. The synchronization detector 230 detects a synchronization signal from the demodulated signals. This synchronization signal is a predetermined signal. The spindle motor rotation control unit 250 counts the period of the synchronization signal at a predetermined clock, converts the difference between the count value and a predetermined value into a rotation control signal, and outputs the rotation control signal to the motor driving unit 260.

2 is a block diagram showing a configuration of a conventional spindle motor rotation control unit. The difference detection unit 252 receives a predetermined reference value REF provided from the microcomputer 240 and a value obtained by counting the synchronization signal in the counter 251, and detects the difference. The detected difference is input to a rotation control signal generator 253, which causes the rotation control signal generator 253 to generate a rotation control signal CTL corresponding to the difference.

When the spindle motor is controlled at 1x speed of the DVD player, a rotation control signal that can be generated by the above-described configuration and operation is generated every detection period of the synchronization signal. Specifically, the period of the synchronization signal is 17.58 MHz according to the following equation (1).

[Equation 1]

The 17.58 MHz is 56.8 sec. However, at 4x, this control period is reduced by a factor of four. 14.2 sec. In this control period, even if a rotation control signal is inputted to the spindle motor, the rotation control signal can not be properly received in the spindle motor. In other words, overhead of the rotation control signal occurs. Here, the overhead means that the motor does not recognize the rotation control signal even if the rotation control signal is input. The magnitude of this overhead increases as the rotational speed of the motor increases.

Accordingly, it is an object of the present invention to provide an apparatus for reducing the overhead during high-speed rotation of a spindle motor.

According to an aspect of the present invention, there is provided a spindle motor high-speed rotation control apparatus for an optical disc driver having a synchronization detecting section for detecting synchronization from a signal read out from an optical disc and demodulated, comprising: A rotation control signal generator for generating a signal for controlling a rotation speed of the spindle motor under a predetermined control, and a control unit for determining whether or not the number of synchronized pulses counted by the counter is within a predetermined range, And a determination unit for transmitting the determination result to the rotation control signal generation unit.

1 is a view schematically showing a configuration of a DVD-ROM driver

2 is a block diagram showing a configuration of a conventional spindle motor rotation control section

3 is a block diagram illustrating the configuration of a spindle motor rotation control unit according to an embodiment of the present invention.

Fig. 4 is a waveform diagram showing the relationship between the synchronizing signal detected by the synchronous detecting section of Fig. 1 and the count signal counted by the counter of Fig. 3

5 is a waveform diagram showing a case where the value obtained by counting the synchronous signal detected by the synchronous detection unit of Fig. 1 by the counter of Fig. 3 is within a predetermined control range

Fig. 6 is a waveform diagram showing a case where the value obtained by counting the synchronous signal detected by the synchronous detection section of Fig. 1 by the counter of Fig. 3 is smaller than the lower limit value of the control range

7 is a waveform diagram showing a case where the value obtained by counting the synchronous signal detected by the synchronous detection section of Fig. 1 by the counter of Fig. 3 is larger than the upper limit value of the control range

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used for the same reference numerals even though they are shown in different drawings. It will also be appreciated that the following description is provided to provide a more general understanding of the present invention, such as specific circuit components and the like, which may be practiced without these specific details, To those of ordinary skill in the art. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The control method of the spindle motor rotating at high speed should be different from that of 1x speed. The reason is that the faster the speed of the spindle motor becomes, the more difficult it becomes to control. If the spindle motor rotates at a high speed, for example, 4 times speed, while the rotation speed of the spindle motor is within the range of a predetermined number of revolutions, a desired rotation speed is maintained for a predetermined time . In other words, the rotation control signal is generated in the spindle motor only when the number of revolutions of the spindle motor exceeds the predetermined number of revolutions, thereby reducing the overhead of the rotation control signal applied to the spindle motor.

The present invention is described in the above-mentioned DVD-ROM driver or CD-ROM driver shown in FIG. 1, and the following description refers to FIG.

3 is a block diagram showing the configuration of a spindle motor rotation control unit according to an embodiment of the present invention. The spindle motor rotation control unit 250B generates a signal CTL1 and CTL2 for controlling the rotation speed of the spindle motor 100 under a predetermined control and a counter 251 for counting the synchronization signal sync provided from the synchronization detection unit 230 in FIG. A determination unit 300 for determining whether or not the number of synchronized counts counted by the counter 251 is within a predetermined range and delivering the determination result to the rotation control signal generation unit 257; .

The determination unit 300 includes an upper limit release unit 254, a lower limit release unit 255, and an AND gate 256. If the number of synchronized pulses counted by the counter 251 is larger than the upper limit value of the predetermined range, the upper limit deviation determining unit 254 controls the rotation control signal generator 257 to increase the speed of the spindle motor So as to generate the signal CTL1 to be controlled. If the number of synchronized pulses counted by the counter 251 is smaller than the lower limit value of the predetermined range, the lower limit deviation determination unit 255 decreases the speed of the spindle motor by the rotation control signal generation unit 257 to a width equal to the second width adjustment signal So as to generate a signal CTL2 for controlling to be controlled. The AND gate 256 outputs a determination signal indicating a logic 'high' state when it is judged to be deviated from one of the upper and lower limits, and a signal indicating 'low' if not. If the output of the AND gate 256 is in the 'LOW' state, the output of the rotation control signal generator 257 indicates the middle value Z _I of the high impedance since it has not departed.

FIG. 4 is a waveform diagram showing the relationship between the synchronizing signal detected by the synchronizing detecting section of FIG. 1 and the count signal counted by the counter of FIG. 3; Assuming that the reference clock is 56 MHz, one cycle of the synchronous signal at the 4x speed is 14.2 sec. Therefore, when the counter 251 counts the value of one cycle of the synchronizing signal, the count becomes 800.

5 is a waveform diagram showing a case where the value obtained by counting the synchronous signal detected by the synchronous detection unit of FIG. 1 by the counter of FIG. 3 is within a predetermined control range, that is, between the upper and lower limits of the rotation speed of a predetermined spindle motor . In this embodiment, the upper limit value is set to 900 and the lower limit value to 700, based on the count value 800 of one cycle of the synchronizing signal. According to the configuration and operation of FIG. 3, the spindle motor rotation control signal is not generated when the ratio is 700 or more and 900 or less. During this time, the rotation state is maintained by inertial force alone. Since the magnitude of the control range is input (REF1, REF2) in the microcomputer 240 in FIG. 1, the range of the control range is easily changed according to the characteristics of the spindle motor.

6 is a waveform diagram showing a case where the value obtained by counting the synchronizing signal detected by the synchronous detection unit of FIG. 1 by the counter of FIG. 3 is smaller than the lower limit value of the predetermined control range. As shown, the count value is 500, which is smaller than the lower limit value 700, which means that the speed of the current spindle motor is fast. Therefore, in the lower limit deviation determination unit 255 of FIG. 3, it is detected that the number 500 of the synchronization signals counted by the counter 251 is smaller than the lower limit value 700 of the predetermined range, and the value 800, which is the reference value, Width control signal so that the rotation control signal generator 257 generates the rotation control signal CTL2 having the corresponding width. The rotation control signal CTL2 is a signal for controlling the speed of the spindle motor to be lowered, the degree of which depends on the difference between the reference value and the count value. As shown in the figure, the rotation control signal CTL2 indicates a low state at a synchronization signal detection timing of the next cycle.

7 is a waveform diagram showing a case where the value obtained by counting the synchronous signal detected by the synchronous detection unit of FIG. 1 by the counter of FIG. 3 is larger than the upper limit value of the predetermined control range. As shown in the figure, the count value is 950, which means that the upper limit value is larger than 900, which means that the speed of the current spindle motor is slow. Therefore, the upper limit deviation determination unit 254 of FIG. 3 detects that the number of synchronization signals 950 counted by the counter 251 is larger than the upper limit value 900 of the predetermined range, and determines that the reference value 800 and the first Width control signal so that the rotation control signal generator 257 generates the rotation control signal CTL1 having the corresponding width. The rotation control signal CTL1 is a signal for controlling the speed of the spindle motor to be increased. The degree of the rotation control signal CTL1 depends on the difference between the reference value and the count value. As shown in the figure, the rotation control signal CTL1 indicates a high state at a synchronization signal detection timing of the next cycle.

As in the case of FIG. 6 or 7, when the current spindle motor is out of the limited range (upper and lower limit values), the width at which the rotation control signal maintains the high or low state is determined according to the deviation. However, since the proportional value differs depending on the characteristics of the spindle motor, the proportional value is set by the microcomputer 240 so as to be easily variable. However, even in the case of the rotation control signal thus obtained, there is a possibility of overhead in a specific spindle motor. In this case, the spindle motor can be output in 1/1 or less by 1/1, .

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

In the present invention as described above, when the spindle motor rotates at a high speed, it generates a rotation control signal only when it deviates from a predetermined range and adjusts the rotation speed. In the remaining case, the rotation control signal is not generated, The overhead can be reduced. Further, the range can be varied according to the characteristics of the spindle motor, and the size of the rotation control signal can be determined to be suitable for the situation in the micom, which is advantageous in that it is easy and convenient to implement. Also, since the frequency of the rotation control signal applied to the spindle motor is reduced, the amount of current naturally used is also reduced.

Claims (10)

A spindle motor high-speed rotation control device of an optical disc driver having a synchronous detection section for detecting synchronization from a signal read out from an optical disc and demodulated, A counter for counting the detected synchronization at a predetermined clock, A rotation control signal generator for generating a signal for controlling a rotation speed of the spindle motor under predetermined control, And a determination unit configured to determine whether or not the number of synchronized counts counted by the counter exceeds a predetermined range, and transmit the determination result to the rotation control signal generation unit. The apparatus of claim 1, And a lower limit deviation determining section for generating a signal for controlling the rotation control signal generating section to lower the speed of the spindle motor when the number of synchronized counts by the counter is smaller than a lower limit value within a predetermined range. . 3. The image processing apparatus according to claim 1 or 2, And an upper limit deviation determining unit for generating a signal for controlling the rotation control signal generating unit to increase the speed of the spindle motor when the number of synchronized counts by the counter is larger than an upper limit value within a predetermined range . 4. The method according to claim 3, And the width of the high or low state is determined in proportion to the deviation from the upper or lower limit value. 5. The method of claim 4, The difference between the lower limit value and the specific count value or half the difference between the specific count value and the upper limit value. The apparatus of claim 1, wherein the optical disk is a digital video disk-ROM. The apparatus of claim 1, wherein the optical disc is a compact disc-ROM. The apparatus of claim 1, wherein the predetermined range set in the determination unit is a variable value provided by the microcomputer of the optical disc driver. A spindle motor high-speed rotation control device of a digital video disk-ROM driver, A synchronization detecting section for detecting synchronization from a signal read out from the digital video disk-ROM and demodulated; A counter for counting the detected synchronization at a predetermined clock, A rotation control signal generator for generating a signal for controlling a rotation speed of the spindle motor under predetermined control, An upper limit deviation determining unit for generating a signal for controlling the rotation control signal generator to increase the speed of the spindle motor when the number of synchronized counts by the counter is larger than a predetermined upper limit value; And a lower limit deviation determining section for generating a signal for controlling the rotation control signal generating section to lower the speed of the spindle motor when the number of synchronized counts by the counter is smaller than a lower limit value within a predetermined range. . The apparatus as claimed in claim 9, wherein the rotation control signal output terminal of the rotation control signal generator indicates a middle value of a high impedance when the number of synchronized counts by the counter is within a predetermined range.