JPS6348104B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a motor rotation control device that can be used mainly in digital audio disc players, video disc players, and the like.

Conventional configuration and its problems Normally, in digital audio disk players, etc., the rotational phase information of the motor recorded on the disk is compared with a rotational reference phase signal to obtain a rotational error signal and perform phase control. However, in order to detect the rotational phase information recorded on the disk, it is first necessary to keep the rotational speed of the motor within a predetermined range. However, normally, the range of rotational speeds in which disk rotational phase information can be detected is relatively narrow, within several percent of the normal rotational speed. That is, it is necessary to control the rotational speed of the disk by another means until the rotational speed reaches a rotational speed at which rotational phase information can be detected. Usually, the number of times the polarity of the signal recorded on the disk is reversed is detected and converted to voltage, and this is used as speed information to roughly control the rotation speed, or the longest period of the signal recorded on the disk is used as the voltage. There are methods to roughly control the rotation speed by converting and holding it as speed information, but in either case, it is necessary to bring the rotation speed under rough control close to the normal rotation speed with a fairly good accuracy. There were other problems.

OBJECTS OF THE INVENTION An object of the present invention is to have an excellent feature in that even if the motor rotational speed is set relatively roughly during the rough control, it is possible to stably transition to the final phase control operation.

Composition of the Invention The motor rotation control device of the present invention includes a motor that drives a disk on which information is recorded in a spiral pattern, a pick-up means for detecting information recorded on the disk, and a detection signal of the pick-up means. a rotational speed detection means for detecting speed information of the pickup means to obtain a rotational speed error signal; a clock extraction means for extracting a motor rotation synchronized clock signal included in the detection signal of the pickup means; and an output signal of the clock extraction means. a phase comparison means for generating a phase error by comparing the phase with a rotation reference clock signal of the motor; and converting the output signal of the rotation speed detection means or the phase comparison means into voltage or current to supply power to the motor. and a rotational speed modulation means that changes the rotational speed of the motor periodically or intermittently, and the rotational speed of the motor is such that the clock extraction means cannot extract a rotation synchronized clock signal. When the number of rotations is the same, a first speed control loop is constituted by the motor, a pick-up means, a rotation speed detection means, and a motor drive means, and the number of rotations of the motor is periodically controlled by the rotation speed modulation means. When the clock extraction means reaches a rotational speed at which it can extract a rotationally synchronized clock signal, the motor, the pick-up means, the clock extraction means, the phase comparison means, and the motor drive A second speed control loop consisting of means is configured, so that even if the speed setting of the first speed control loop is relatively rough,
This has the advantage of being able to quickly enter the second speed control loop.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an overall block diagram of an embodiment of the present invention. 1 is a motor that rotates disk 2; 3 is a pickup for reading information on disk 2; 4 is a pickup that detects the number of times the polarity of the output signal of pickup 3 is reversed and converts it into a voltage;
A rotational speed detection circuit uses speed error information, and 5 is a clock extraction circuit. Normally, when the disk 2 reaches a predetermined rotational speed range, the motor rotation included in the information recorded on the disk 2 is detected. It operates to extract the clock signal. Reference numeral 6 denotes a phase comparison circuit which compares the phase of the rotational reference clock signal _fs and the output signal of the clock extraction circuit 5 and generates a voltage corresponding to the phase error. Reference numeral 7 denotes a motor drive circuit that receives an output signal from either the rotational speed detection circuit 4 or the phase comparison circuit 6 and supplies current to the motor 1. A switch 8 is controlled depending on the operating state of the clock extraction circuit (whether clock extraction is being performed or not). The motor 1, the pickup 3, the rotation speed detection circuit 4, and the motor drive circuit 7 constitute a speed control loop, and when the speed control loop is in operation, the output of the oscillator 9 is added to the output of the rotation speed detection circuit 4. The rotational speed of the motor 1 is changed periodically or intermittently. The motor 1, the pickup 3, the clock extraction circuit 5, the phase comparison circuit 6,
The motor drive circuit 7 constitutes a phase control loop, and during operation of this phase control loop, the motor 1 is controlled to constant rotation by the phase reference frequency fs.

Figure 2 is a graph showing the operation of the motor when it starts to rotate;
A shows the state when the oscillator 9 is operated and a periodic disturbance is applied to a part of the loop to cause periodic fluctuations in the rotational speed of the motor 1, and A shows the state when the oscillator 9 is not operated. In the diagonally shaded area surrounded by the rotational speeds _N1 and _N2 , the clock extraction circuit 5 operates to extract the clock signal contained in the disk 2, and at the same time connects the switch 8 to the b side. The switch 8 is connected to the a side in a range constituting a phase control loop based on _s , and in other ranges, it constitutes a speed control loop controlled by the speed error output of the rotational speed detection circuit 4. The target rotation speed in controlling this motor is N _p , which is synchronized with the reference signal f _s .
The operating rotational speed N ₃ during the speed control loop needs to be as close to N _p as possible. However, as shown in the example in Fig. 2, if the rotational speed N ₃ during the fast-acting control loop is set outside the range of N ₁ N ₂ , the clock extraction circuit will not operate and the switch 8 will remain closed forever. is not switched to the b side, and the phase control loop is not established.

However, in the case of the present invention, when the oscillator 9 forcibly applies rotational fluctuations to the motor 1 as shown in B, the set rotational speed of the speed control loop is within the range of _N1 and _N2 , such as _N3 . Even if it is outside, the rotation speed of motor 1 itself changes periodically by increasing and decreasing around N ₃ , so it may be within the range of N ₁ and N ₂ at a certain moment. I can do it. Once within this range, the clock extraction circuit 5 operates to switch the switch from a to b, creating a phase control loop with _fs as the reference, and reducing the rotational speed of the motor 1 to _N0 . can.

The rotational speed detection circuit 4 used in this embodiment may be a system that uses a frequency-voltage conversion circuit that converts the number of polarity inversions or frequency of the output signal of the pickup 3 into a voltage, or a system that uses a frequency-voltage conversion circuit that converts the maximum period of the output signal of the pickup 3. One possible method is to use a circuit that converts it into voltage.

Figure 3a shows an example of the configuration of the frequency-voltage conversion circuit that constitutes the rotational speed detection circuit 4, where 10 is a one-shot multi-vibrator, and 11 and 12 are resistors for integrating the one-shot pulse width and converting it into voltage. and a capacitor. FIG. 3b is a time chart showing the waveforms of each terminal in FIG. 3a, qualitatively showing that the input frequency G and the output voltage I are proportional.

FIG. 4a shows an example of a configuration in which the rotational speed detection circuit 4 detects the longest period in input information and converts it into a voltage.
These are the resistors and transistors that make up the switch that turns on and off the charge circuit that consists of 24 and 25 are operational amplifiers and diodes constituting a peak level detector that detects the maximum value of the input level; 26 and 27 are for holding the peak level for a certain period of time with appropriate attenuation characteristics; A capacitor and a resistor 28 are a voltage follower circuit forming a buffer. FIG. 4B is a time chart showing the waveforms of each terminal in FIG.

Effects of the Invention As is clear from the above explanation, the present invention has the advantage of roughly controlling the set speed of coarse control (speed control) of the motor before entering into the phase control operation that controls the motor using the phase information recorded on the disk. Even if you set
It has the characteristic that it can be reliably engaged in phase control operation.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of a motor rotation control device according to an embodiment of the present invention, Fig. 2 is a time chart showing its operating state, and Fig. 3 a and b are an example of the configuration of a rotation speed detection circuit. and a time chart showing its operation. FIGS. 4a and 4b show another example of the configuration of the rotational speed detection circuit and a time chart showing its operation. 1...Motor, 3...Pickup, 4...Rotation speed detection circuit, 5...Clock extraction circuit, 6...
...Phase comparison circuit, 7...Motor drive circuit, 8...
Switch, 9...oscillator.

Claims (1)

[Scope of Claims] 1. A motor for driving a disk on which information is recorded in a spiral pattern, a pickup means for detecting information recorded on the disk, and a pickup means for detecting speed information included in a detection signal of the pickup means. a rotational speed detection means for obtaining a rotational speed error signal from the pickup means; a clock extraction means for extracting a motor rotation synchronized clock signal included in the detection signal of the pickup means;
a phase comparing means for generating a phase error by comparing the phase of the output signal of the clock extracting means and a rotation reference clock signal of the motor; and the rotational speed detecting means;
or motor drive means for converting the output signal of the phase comparison means into voltage or current and supplying electric power to the motor; and rotation speed modulation means for periodically or intermittently changing the rotation speed of the motor; When the rotational speed of the motor is such that the clock extraction means cannot extract a rotation synchronized clock signal, the first speed control consisting of the motor, the pick-up means, the rotational speed detection means, and the motor drive means is performed. A loop is formed, and the rotation speed of the motor is changed periodically or intermittently by the rotation speed modulation means, and the rotation speed reaches a speed at which the clock extraction means can extract a rotation periodic clock signal. 1. A rotation control device for a motor, characterized in that when the above-mentioned motor, a pick-up means, a clock extraction means, a phase comparison means, and a motor drive means form a second speed control loop. 2. The motor rotation control device according to claim 1, wherein a circuit for converting the longest period of the output signal of the pickup means into a voltage or current value is used as the rotation speed detection means. 3. The motor rotation control device according to claim 1, wherein the rotation speed detection means uses a circuit that converts the number of polarity inversions of the output signal of the pickup means into a voltage or current value.