JPH03289387A - Motor servo circuit - Google Patents

Abstract

PURPOSE:To drive a motor by a suitable servo gain by detecting the deviated amount of rotation of reproduction at the time of initial reproduction of the reproducing surface of a disc, and varying a reference servo gain to an optimum servo gain on the basis of the optimum gain based on the detection. CONSTITUTION:If a reproducing surface becomes a reproducible rotating state, the fall of a reproducing horizontal synchronizing (PBH) signal is compared with that of a reference horizontal synchronizing signal (REFH signal) of a terminal 2 by a phase comparator 3 in which the PBH signal is input, and it supplies an ERR (phase error) signal having a pulse width corresponding to the difference. A deviation detector 9 detects the magnitude of the varying range of the ERR signal, and supplies it to a gain deciding circuit 10. Suitable servo gain is decided based on preset characteristic, a correction constant alphais obtained, and a servo gain correction constant is varied from an initial constant alpha0 to alpha. Further, the ERR signal and the constant alpha are supplied to a duty modulator 11 to become a second ERR, which is supplied to a motor driver 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a motor servo circuit that is provided in a disc reproducing device for optical discs and the like and controls the phase or speed of a rotating piece of a disc or a Tanabata drive.

[Conventional technology]

Conventionally, in a reproducing apparatus for an LD, which is an example of an optical disk, a four-way phase servo of a spindle motor for rotationally driving the LD is configured as shown in FIG.

(1) is the input terminal of the LD reproduction horizontal synchronization signal (hereinafter referred to as PBH signal), and (2) is the input terminal of the reference horizontal synchronization signal of the reference phase formed by oscillation (hereinafter referred to as REFH signal). Terminal, (3) is phase comparison circuit, (4)
(5) is a phase compensation circuit, (6) is a motor drive circuit, and (7) is a spindle that drives the It-ILD.

When regenerating the LD mounted and held in the chucking device, the converter (7) is first driven by a four-way motor drive (6) based on a speed error signal of a speed servo circuit (not shown).
It is activated by the drive of

When the width speed of the motor (7) begins to reach the specified speed due to this activation, the rotation of the motor (7) by 4 degrees is pulled to the specified speed by the speed servo based on the speed error signal.

When the speed servo starts to be applied, the LD enters a rotating state in which its reproduction surface can be reproduced, and information on the reproduction surface begins to be reproduced by an optical pickup (not shown).

Then, the horizontal synchronizing signal included in the reproduction information is supplied as a PBH signal to the input terminal (1), and the phase servo circuit of the comparator circuit (3), the amplification path (4), and the phase compensation circuit (5). starts working.

That is, when a PBH signal is supplied to the input terminal (1), the phase of this PBH signal and the reference phase of the REFH signal of the input terminal (2) are compared in the phase comparison circuit (3). ) to the integral amplifier circuit (4), e.g. PB
A phase error signal (hereinafter referred to as an ERR signal) corresponding to the amount of deviation of the phase of the H signal from the reference phase is supplied.

Then, the ERR signal is subjected to low-pass filter processing and multiplied by the integral amplifier circuit (4), then corrected according to the phase amount in the two-phase compensation circuit (5), and then supplied to the drive circuit (6). be done.

At this time, the circuit constants of the integral amplifier circuit (4) and the 1-phase compensation circuit (5) are such that the DC characteristic of the servo gain of the 1-phase servo circuit is LD, the periodic time axis fluctuation of rotation based on the eccentricity of the chucking device, In other words, the settings are made so that the characteristics suppress the rotational eccentricity of the reproduction surface.

and by phase servo based on the ERR signal.

The rotational phase of the motor (7) suppresses the eccentricity caused by the @I transmission and begins to be drawn into the reference phase.

After that, the motor (7) is controlled by the speed servo and phase servo.
is servo-driven to rotate at a specified speed and reference phase.

Also included in Figure 8 (spindle servo block diagram) on page 78 of the January 1989 issue of the magazine "Television Technology" (Denshi Gijutsu Publishing Co., Ltd., published on January 1, 1986).

A phase servo circuit for a spindle motor corresponding to FIG. 5 is described.

[Problem to be solved by the invention]

In the case of the conventional four-way phase servo shown in FIG. 5, the circuit constants of the integral amplifier circuit (4) and the phase compensation circuit (5) are used.

Custom-made servo gain (phase gain) has specific characteristics.

In other words, the characteristic σ is fixed to be optimal for a rotational eccentricity of standard magnitude.

Therefore, it is extremely difficult to set the servo gain characteristics to cover the entire range of rotational eccentricity based on variations in the eccentricity of the LD and chucking device. There is a problem that the more extreme the amount, the more the servo gain deviates from the appropriate value and the accuracy of the servo drive decreases.

The same problem as described above occurs even when the circuits of playback devices for various discs other than LD are considered.

In addition, for example, the 5th section integral amplifier circuit (
4) When a phase compensation circuit (5) is provided and the speed error signal is corrected for the eccentricity of rotation, the same problem as the fifth factor of the phase servo circuit occurs in the speed servo circuit. .

The purpose of this invention is to provide a motor servo circuit that servo-drives a motor with an appropriate servo gain according to the amount of eccentricity of rotation of a playback aid, regardless of variations in eccentricity of IBl:Iu, disks, and chucking devices. shall be.

[Means to solve the problem of caterpillars]

In order to achieve the above-mentioned purpose, the unfired motor servo circuit is configured to rotate the disk during at least one rotation of the disk immediately after the disk reaches a reproducible rotational state for the first time on the reproducing surface by servo driving with a reference servo gain. an eccentricity detection path for detecting an amount of deviation of the phase of the synchronization signal reproduced from the B1 phase as an eccentricity of rotation with respect to the reproduction surface based on the eccentricity of the disk and the chucking device;

a gain determining circuit that determines an optimal servo gain according to the detected amounts of the four detection paths;

and gain variable means for varying the gain of the servo drive from the reference servo gain to a gain determined by a determination circuit described separately.

[For production]

In the case of the motor servo circuit of the present invention configured as described above, at the time of first reproduction of the reproduction surface of the disk.

Based on the servo drive at the standard servo gain, the eccentricity of rotation is detected by the eccentricity detection circuit.

Further, based on the detection by the eccentricity detection circuit, a gain determination circuit determines an optimum surfo gain according to the amount of rotational eccentricity with respect to the reproduction surface.

Then, the gain switching means changes the gain of the servo drive to the determined optimum servo gain.

Therefore, the gain of the servo drive is varied to an appropriate value according to the actual rotational eccentricity of the playback surface, and the disc
Appropriate servo drive is performed regardless of variations in eccentricity of the chucking device.

〔Example〕

One embodiment will be described with reference to FIGS. 1 to 4.

In Fig. 1, the same symbols as in Fig. 5 indicate the same or equivalent parts, (8) is the FG double signal input terminal as the speed detection signal of the motor (7), and (9) is the eccentricity detection circuit. ,
OFF is a gain determining circuit, and q is a duty modulation circuit that forms the gain switching circuit.

and a 1-phase comparison circuit (3) and an eccentricity detection circuit (9).

The gain determining circuit QG and the duty modulating circuit αυ are formed by a microcomputer circle.

Also, click on Figure 2, which shows the configuration of the eccentricity detection circuit (9), the gain determination circuit QQ, and the duty modulation circuit aυ.
(9a) and (9b) are the ERR of the phase comparator circuit (3)
These are a maximum value latch unit that holds the maximum value and minimum value of the signal, and a subtracter that calculates the difference between the outputs of the minimum value as an amount of eccentricity.

(10a) is an arithmetic unit that calculates a correction constant α for proper servo gain, and (]Ob) is a memory that holds the constant α.

(Ila) and (llb) are down counters and up counters.

(IIC) is a multiplier for servo gain correction.

Then, when regenerating the LD mounted and held in the chucking device, the motor (7) is started by the speed servo circuit as in the conventional case.

As a result of this activation, when the four speeds are pulled up to the specified speed and the playback surface is in a state of rotation that allows playback, the PBH bond number shown in FIG. Ru.

1 phase comparison path (3) is connected to the falling edges tx+, tx2 . of the PBH signal in FIG. 3(a). ... and the same figure ('b)
The input terminal shown in (falling trl of REFH double of 2
, tr2, · and the falling position txt, tX
2, the falling edge of tr+, tr2. The pulse width t+ in both figures (C) corresponds to the difference from t2.・
The eccentricity detection circuit (9
), which is supplied to the duty modulation circuit αυ.

Note that the pulse widths t+, t2. The data of ... is based on the count of the internal clock of microcomputer hitting period τ(b, t2, and as shown in Fig. 3(d), 1+=n1・τ t2=n2・τ, . . . Along with being asked for.

It is formed by adding positive and negative signs corresponding to the lead and lag.

The eccentricity detection circuit (9) includes a timing control section (9c).
)yo, 9. When it is detected that the FG double signal has reached the reproducible rotation state, the latch portions (9a) and (9b
) is driven to open the LD at a predetermined rotational speed.

Due to this immediate action, the rasochi parts (9a) and (9b) automatically turn the latch and latch the data of ERRfg for the maximum pulse width and minimum pulse width during the predetermined rotation speed, and The maximum and minimum values of the number are retained.

In addition, the latch outputs of the launch sections (9a) and (9b) are supplied to a subtractor (9d) K, and this subtracter (9d) calculates the wide range of fluctuation of the ERR signal, that is, the phase of the PBH signal. The amount of deviation of the REFH signal from the reference phase is detected.

And the large fluctuation range of the ERR signal is LD.

This corresponds to the eccentricity of rotation with respect to the reproducing surface based on the eccentricity of the chucking device, and the eccentricity of rotation is detected and calculated by the output of the subtractor (9d).

To the whistles, (tj, the output of the X device (9d) determines the gain 6
is supplied to the arithmetic unit (]Oa) of the path QO, and this arithmetic unit (l
oa) K, preset determining characteristic 1, e.g.
Based on the characteristics shown in the figure, an appropriate servo gain for the amount of eccentricity is determined, and a correction constant α for this gain is determined.

In Figure 4, when the PBH multiplier becomes a delayed phase and the eccentricity decreases in the negative direction, the correction constant α is changed to α.
When the servo gain increases and the PBH signal advances in phase and the eccentricity increases in the positive direction,
The determination characteristic is set so that the correction constant α is decreased by αmin t to decrease the servo gain.

It was a cabinet. ta and tb in FIG. 4 indicate the upper and lower limits at which the constant α is saturated.

Then, when the constant α is calculated and determined by the calculation unit (]Oa), this constant α is memorized! 1 is written to J (10b).

Memo based on this post! The servo gain correction constant held in J(]Ob) changes from the reference servo gain constant αO, which is a preset initial value, to the determined constant α.

Furthermore, the ERR signal of the phase comparison four-way (3) and the memory (j
The constant α of the duty modulation circuit αD is the constant α of the duty modulation circuit αD.
IIC) K is supplied and this multiplier (IIC) K is supplied.

ERR signal A/IX width data ylt-r (=tt
), nt-r(=tz).

... is multiplied by α, α・nl・τ α・nt・τ,...
* data is supplied to the counter (llb).

This key 1. Counter (Il'a) Fi, Micro Conch.

When the count value reaches O due to down counting of the internal clock CK of the user 0, the data of the modulation period T shown in FIG. The down count is returned to <b, and the modulation period T is repeatedly measured.

I cut it. The counter (Ila) is instantaneously reset in synchronization with the self-reset of the counter (Ilb), and from this reset, counts the internal clock CK of the pulse width data of the ERR signal, and converts the ERR signal into α, nt, and τ. , α・
A corrected phase error signal (hereinafter referred to as second ERR multiple) is formed by modulating the pulse width to a pulse width of nt·τ, .

Then, the second ERR signal is supplied to the integral amplifier circuit (4) instead of the ERR signal b, and the second ERR signal via this circuit (4) and the 1-phase compensation circuit (5) is supplied to the motor drive circuit (b).
6).

At this time, the characteristics of the servo gain based on the integral amplifier circuit (4) and the 2-phase compensation 4-way (5) are fixed, but since the ERR1 word changes to the 2nd ERRIB word, the servo gain changes due to the rotational bias regarding the re-screening. Switches to the optimum gain according to the core amount.

Therefore, the integral amplifier circuit (4), the 1-phase compensation circuit (5)
Eccentricity can be suppressed very well as in the phase servo of the Iika servo gain without making the servo gain characteristics cover the entire range of variations in eccentricity.

Then, the constant α of the memory (10b) is held and multiplied by the casing where the LD installed and held in the chucking device is replaced. (IIc).

When playing an LD with information recorded on both sides of the casing, the first time each side is played.

Each correction constant has been calculated and determined! J (10
b), and the correction constants for both sides are alternatively read out to a multiplier (IIC) depending on the reproduction surface.

By the way, instead of performing the calculation in the calculation unit (10a) by setting the formula for the determining characteristic shown in FIG. 4, a table of combinations of eccentricity and constant α according to the determining characteristic is set, If you do it using /L/.

It's extremely easy to do.

The determined characteristic is set σ depending on the eccentricity characteristics of the disk, the chucking device, and the like.

It was a cabinet. In the above embodiment, the application was applied to the phase servo circuit of the spindle motor (7) of the LD playback device, but it can also be applied to a motor for driving the rotation of the disk of a weak disk playback device, such as a phase servo circuit of the spindle motor of the Cυ playback device. The synchronization signal can be applied to the phase servo when it is played from the disk.

The reference phase synchronization signal may be any signal equivalent to the PBH signal or REFH signal.

Furthermore, the present invention may be applied to a speed servo circuit, and the ERR signal may be used as a speed error signal.

According to the above embodiment, one phase comparator circuit (3)
, the eccentricity detection port (9), the gain determining circuit QG, and the duty modulation circuit σD are formed by the microcomputer O, but they may be formed by discrete circuits.

〔Effect of the invention〕

The present invention is constructed as described in one or more Therefore, the following effects are achieved.

When the playback surface of the disk is played for the first time, the amount of rotational eccentricity on the playback surface is detected from the phase difference between the eccentricity detection path and the standard servo gain, and based on this detection, the gain determination circuit determines the optimum servo gain. was determined, and based on this determination, the gain of the servo drive was varied from the reference servo gain to the optimum servo gain by the gain variable means.
Regardless of variations in eccentricity of the disc or chucking device.

The motor can be servo-driven with a gain that can best correct rotational eccentricity.

[Brief explanation of drawings]

1 to 4 show one embodiment of the motor servo circuit of the present invention, FIG. 1 is a block diagram, FIG. 2 is a partial detailed block diagram, and FIGS. 3(a) to (e) is a timing chart for explaining the operation, Figure 4 is a characteristic diagram of gain determination, and Figure 5 is a timing chart for explaining the operation.
The figure is a block diagram of a conventional example. (3)...Phase comparison circuit, (7)...Spindle motor, (9)...Eccentricity detection circuit, QG...Gain determination circuit, αυ...Duty modulation circuit as gain variable means .

Claims (1)

[Claims] (1) In a motor servo circuit that is provided in a disc playback device that rotates and plays back a disc that is mounted and held in a chucking device and that servo drives a motor for rotating the disc, the servo drive has a reference servo gain. Immediately after the disk reaches a rotational state in which playback is possible for the first time on the playback surface, the amount of deviation of the phase of the synchronization signal reproduced during at least one rotation of the disk from the reference phase is determined for the disk and the chucking device. an eccentricity detection circuit that detects an eccentricity amount of rotation about the reproduction surface based on the eccentricity; a gain determination circuit that determines an optimal servo gain according to the detected amount of the detection circuit; A motor servo circuit comprising gain variable means for varying a reference servo gain to a gain determined by the determination circuit.