KR960001758B1 - Spindle servo circuit for ldp - Google Patents

Abstract

The circuit includes a pickup unit which reads information from a rotating laser disc, a synchronization signal detecting unit which detects output synchronization signals from read information, a phase comparing unit which detects phase error, a power amplifying unit which amplifies output signal to operate spindle motor, a phase detecting circuit which outputs the first and second switching signals for optimum gain control, a gain control unit which provides optimal gain for accelerating the servo to maximum speed, a switching unit which selects the output of a compensating unit and the maximum gain of the gain controlling unit, and an adding unit which supplies optimal gain to the power amplifying unit by adding the outputs of the compensation and the gain control units.

Description

Spindle servo circuit for reduced start-up time of laser disc player

1 is a block diagram illustrating a spindle servo system employed in a conventional laser disk player.

2 is a diagram showing a configuration of a spindle servo circuit for reducing the start time of a laser disc player according to the present invention;

FIG. 3 is a timing diagram for explaining the operation of the start time reduction spindle servo circuit shown in FIG.

* Explanation of symbols for main parts of the drawings

10: laser disk 12: spindle motor

14 pickup device 16 synchronization signal detection unit

18: phase comparator 20: compensator

22: power amplifier 30: phase detection circuit

31: gain control unit 32, 33: switching element

34: adder

The present invention relates to a spindle servo circuit for reducing the startup time of a laser disc player. More particularly, the present invention provides a high speed access to a laser disc by reducing a delay time from the time when the laser disc is mounted to the normal screen reproduction. The present invention relates to a spindle servo circuit for shortening the start time of a laser disc player.

Currently, a laser disc player for reproducing a disc that is noted as a large-capacity information recording medium, in particular a laser disc capable of reading information including a video signal and an audio signal, employs a phase servo structure spindle servo system as shown in FIG. In order to reproduce the data from the laser disk, the spindle servometer shown in FIG. 1 is picked up with a reference phase signal θr for maintaining constant rotation of the spindle motor 12 that drives the laser disk 10. A phase comparator 18 which detects a phase difference by comparing the phase signal θ extracted by the synchronization signal detector 16 in a signal read out from the disc 10 by the device 14, and the phase comparator 18 Compensator 20 for compensating the phase difference obtained in the step, power amplifying the compensation signal provided from the compensator 20 to drive the spindle motor 12 for the rotational drive of the laser disk 10 It consists equipped with aeration (22).

According to the spindle servometer having the structure shown in FIG. 1, the reference comparator 18 (i.e., the reference phase signal [theta] r) and the horizontal synchronizing signal (i.e., the phase signal [theta]) from the disc 10 are used in the phase comparator 18. FIG. In comparison, normal screen reproduction is performed only when the angular velocity of the horizontal synchronizing signal from the disc 10 becomes normal.

By the way, according to the spindle servometer of the conventional laser disc player shown in FIG. 1, in the transient state period until the steady state is reached by detecting the synchronization signal recorded on the disc 10 to control the speed of the disc. Due to the design of the mechanism, it takes a considerable amount of time and, in addition, it takes a relatively long time from the point where the laser disc player operates the play button (PLAY) to the laser disc with a relatively large moment of inertia. to be.

In addition, in the spindle control system of the conventional laser disk player shown in FIG. 1, the driving voltage is applied to the spindle motor 12 while the reference synchronization signal θr is generated in the form of a phase locked loop (PLL). In the initial stage (frequency introduction period and transient state period) when the spindle motor 12 starts to start, the reference synchronization signal θr and the output synchronization signal θ from the disk 10 obtained by the synchronization detection unit 16 are generated. When the rotational speed of the spindle motor 12 increases after a certain amount of time has elapsed, the reference synchronous signal θr and the output synchronous signal θ coincide with each other to match phases. In such a phase synchronization loop, when the frequency between the reference synchronization signal and the output synchronization signal does not match, the spindle servo system not only performs nonlinear operation but also considerably delays the arrival time to the steady state.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and shortens the time required for the frequency introduction process from the time when the reference synchronous signal is generated when the laser disc is started until the reference synchronous signal matches the output synchronous signal from the disc. It is an object of the present invention to provide a spindle servo circuit for reducing the startup time of a laser disc player, which minimizes the transient period until the disc drive is stabilized by using the optimum gain calculated in advance.

In order to achieve the above object, according to the present invention, a pickup device for reading information from a laser disk when the spindle motor rotates at a reproducible rotation speed, and a synchronization for detecting an output synchronous signal from the information read by the pickup device. A laser disk comprising a signal detector, a phase comparator for detecting a phase error in the output synchronous signal and a reference synchronous signal, a compensator for compensating the phase error, and a power amplifier for driving the spindle motor by amplifying the output of the compensator. In the player, a phase for detecting the first rising edge of the reference synchronous signal and the output synchronous signal from the phase error of the phase comparator during the initial driving of the spindle motor and outputting the first and second switching signals for optimum gain control. A detection circuit; A gain control unit that provides a predetermined maximum acceleration and optimum gain for a frequency introduction period and a transient state period during the initial driving of the spindle motor, an output of the compensator according to a switching signal of the phase detection circuit, or a maximum gain from the gain control unit And a switching means for switching a circuit, and an adder for adding an output of the compensator connected by the switching means and an output of the gain control unit to apply an optimum gain to a power amplifier. Circuitry is provided.

According to the above configuration, according to the output of the phase comparator, the phase detection circuit detects the first rising edge of the reference signal and the output synchronization signal to generate a switching signal, and the switching means selects the maximum gain by the switching signal. Since the spindle motor can be driven at a normal speed in a short period of time during the transient state, it is possible to shorten the delay time generated in the laser disk player.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a diagram showing the configuration of the spindle servo circuit for shortening the start time of the laser disk player according to the present invention, and the same or similar components as those shown in FIG. 1 will be described with the same reference numerals.

Referring to FIG. 2, the phase detection circuit 30 is connected to the outputs UP and Down of the phase comparator 18. The phase comparator 18 has two types of outputs UP and Down. When the frequency of the output synchronization signal θ provided by the synchronization signal detection unit 16 is lower than the frequency of the reference synchronization signal θr, the output UP is activated and applied to the spindle motor 10. When the voltage is increased and the frequency of the output synchronous signal θ becomes higher than the frequency of the reference synchronous signal θr in the transient state for stabilizing the reference speed after such frequency introduction period, only the output DW signal is active. Since the voltage applied to the spindle motor 12 is reduced, the phases of the two synchronization signals? R and?

That is, referring to the timing diagram shown in FIG. 3, t1 is a time point at which the reference synchronous signal θr is generated, t2 is a time point at which the output synchronous signal θ reaches a target rotational speed, and is a period of t1 to t2. This is the frequency introduction period until the spindle motor 12 reaches a steady state, so that the output DW of the phase comparator 18 remains inactive during the frequency introduction period (Fig. 3 (a, b) )Reference).

The phase detection circuit 30 detects the outputs UP and DW of the phase comparator 18 and detects the first rising edges of the reference synchronous signal θr and the output synchronous signal θ, and thus the frequency introduction period t1-. At t2, the switching control signal CS1 and the inverted signal CS2 shown in FIG. 3 (c, d) are outputted.

On the output side of the switching control signal CS1 of the phase detection circuit 30, a switching probe 32 for switching the maximum acceleration C1 and the optimum gain C2 provided from the gain control unit 31 is connected. On the output side of the switching control signal CS2, a switching element 33 for turning on / off the output of the compensator 20 is linked.

The gain control unit 31 is calculated in advance to minimize the time delay caused in the frequency introduction period of the spindle motor 12, the maximum acceleration is calculated in advance so that the spindle servometer takes the shortest time to enter the steady state (C1) and optimum gain (C2) will be provided.

In addition, the maximum acceleration C1 of the spindle motor 12 applied from the gain control unit 31 during the frequency introduction period between the switching element 32 and the power amplifier 22, and the compensator 20 during the transient state period. There is provided an adder 34 for generating a servo signal for shortening the transient state period of the spindle motor 12 by adding the maximum gain C2 of the gain control unit 31 and the gain.

According to the spindle servo circuit for shortening the start time of the laser disk player of the present invention configured as described above, the current synchronization signal detected by the synchronization signal detection unit 16 in the information read out from the laser disk 10 by the pickup device 14. The phase detection circuit 30 detects the output of the phase comparator 18 which obtains a phase error by comparing [theta] and the reference synchronization signal [theta] r. In this case, during the frequency introduction period t1-t2, the phase detection circuit 30 outputs the switching control signals CS1 and CS2 to switch the switching element 33 to the maximum acceleration C1 side of the gain control unit 31. In addition, the switching element 33 is blocked, and accordingly, the maximum acceleration C1 is applied to the spindle motor 12 through the adder 34 and the power amplifier 22, so that the spindle motor 12 is driven at the maximum acceleration. This minimizes the frequency introduction process.

Then, in the transient state period after time t2, the phase detection circuit 30 connects the switching element 33 and switches the switching element 32 to the optimum gain C2 side. Therefore, since the spindle servometer is normally configured, the output of the compensator 20 is applied to the adder 34 through the switching element 33 and the optimum gain C2 from the gain control unit 31 is the switching element ( 32 is applied to the adder 34. The adder 34 adds the normal servo signal and the maximum gain C2 to generate a servo signal that minimizes the time required for the spindle servo system to enter the normal state, thereby generating the servo motor through the power amplifier 22. As a result, transient periods can be minimized.

As described above, according to the spindle servo circuit for shortening the starting time of the laser disk player according to the present invention, the spindle motor is driven by the maximum acceleration calculated as optimization data in advance during the frequency introduction period of the driving synchronous of the spindle motor. In the transient period, it is possible to minimize the transient period of the spindle motor by providing the output of the normal compensator and the maximum gain calculated as pre-optimization data, thus minimizing the time required for the spindle servometer to enter the steady state. The delay in time until the image is output is alleviated to a considerable extent, which can resolve the dissatisfaction of consumers.

On the other hand, although the present invention has described a laser disc as a disc having a time delay in the above description, it is obvious that the present invention can also be applied to an information storage medium such as a compact disc having a time delay until the first reproduction.

Claims (2)

A pickup device 14 which reads information from the laser disk 10 when the spindle motor 12 rotates at a reproducible rotational speed, and an output synchronous signal θ from the information read by the pickup device 14; A synchronous signal detector 16 for detecting, a phase comparator 18 for detecting phase errors in the output synchronous signal θ and a reference synchronous signal θr, a compensator 20 for compensating for the phase error, and the compensator ( In the laser disk player comprising a power amplifier 22 for driving the spindle motor 12 by amplifying the output of the output 20, the phase error of the phase comparator 18 when the spindle motor 12 is initially driven. A phase detection circuit 30 which detects the first rising edges of the reference synchronization signal θr and the output synchronization signal θ from and outputs first and second switching signals CS1 and CS2 for optimum gain control; ; The gain control unit 31 and the phase detection circuit 30 which provide a predetermined maximum acceleration C1 and an optimum gain C2 for the frequency introduction period and the transient state period during the initial driving of the spindle motor 12. Switching means for switching the output of the compensator 20 or the maximum gain from the gain control section 31 in accordance with a leveling signal, the output of the compensator 20 and the gain control section 31 connected by the switching means. And an adder (34) for applying an optimum gain to the power amplifier (22) by adding the output of the spin amplifier circuit. The switching device of claim 1, wherein the switching means is switched by the first switching signal CS1 during initial driving of the spindle motor 12 to switch the maximum acceleration C1 and the optimum gain C2. And a switching element (33) for opening and closing the output of the compensator (20) by the second switching signal (CS2).