JP2001333588A - Revolution controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor revolution controller, having a low-frequency compensation filter which prevents a response waveform of a revolution of a spindle motor from overshooting to enable stable operation, even if the output signal of a loop filter is saturated, when the target revolution of the spindle motor is changed significantly. SOLUTION: This revolution controller has a feedback loop, which controls motor revolution to be a prescribed value. A low pass compensation filter 102, which compensates a gain of a low frequency component of an error signal in the feedback loop and a saturation detection means 107, which detects the saturation of a drive signal in the feedback loop are provided. The gain of the low-pass compensation filter 102 is reduced according to the saturation detection signal of the output of the saturation detection means 107.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation control device for controlling the rotation of a spindle motor in an optical disk device such as a CD (compact disk) and MD (mini disk).

[0002]

2. Description of the Related Art At present, optical disks represented by CDs are rapidly spreading as audio recording media, and are characterized by random access, high sound quality by digital processing, and no deterioration in sound quality due to long-term use. is there. In particular, MDs are different from CDs, which are read-only optical disks, and are being accepted in a wide range of markets, especially for young people, because they can be easily recorded and played by ordinary users. Due to the simplicity of having only about half the size, portable playback devices have been rapidly spreading recently.

An important point in the development of such a portable reproducing apparatus is an effort to save power. The main source of power for portable playback devices is batteries,
The issue is how to achieve a long-term reproduction operation with limited power obtained from a battery. For that purpose, it is necessary to reduce the power consumption of the device.

As techniques for saving power in a conventional portable reproduction apparatus for CDs and MDs, techniques for reducing the circuit scale by integrating circuits, lowering the operating voltage of the circuits, and the like have been developed. Time has been realized.

Further, in the case of MD, in order to record an audio signal for a time equivalent to that of a CD on an optical disk having a disk diameter of about half of a CD, the audio signal is compressed to about one-fifth by a compression technique and recorded. .

[0006] By utilizing this feature, in an MD system, data reproduced from an optical disk is temporarily stored in a memory, and the stored data is expanded to generate an audio signal. While sufficient data is stored in the memory, it is not necessary to newly reproduce data from the optical disk, and the circuit for reproducing data from the optical disk can be stopped. Also,
If the amount of data stored in the memory becomes small, new data may be reproduced from the optical disk and stored in the memory.

The intermittent drive reproduction technique for repeatedly stopping and resuming the data reproduction operation can reduce the power consumption due to the redundant operation of the reproduction circuit, greatly contributing to the power saving of the optical disk apparatus. .

A conventional optical disk device according to the following technology will be described with reference to FIGS. 5, 6 and 7. FIG.

FIG. 5 is a block diagram showing a schematic configuration of an MD player as a conventional optical disk device provided with an intermittent drive reproduction technique for reducing power consumption.

[0010] The optical pickup 502 condenses laser light by an objective lens and reads out a signal from the optical disk 501.

The RF unit 503 performs signal processing on the signal read by the optical pickup 502, and outputs a focus error signal and a tracking error signal, which are position error signals for controlling the position of the optical pickup 502, to a PU ( Pickup) EFM that outputs to servo section 510 and transmits main information such as a compressed audio signal.
An (8-14 modulation) signal and an ADIP (address) signal for transmitting position information on the optical disk 501 are processed by the signal processing unit 50.
4 is output.

The focus error signal is a signal indicating a positional error between the focal point of the laser beam and the recording surface of the optical disk 501, and the tracking error signal is a signal indicating the position error.
1 is a signal indicating a position error between a focal point of a laser beam and a recording track on the recording surface of No. 1;

The PU servo unit 510 controls the position of the objective lens perpendicular to the recording surface of the optical disk 501 based on the focus error signal, focuses the laser beam on the optical disk surface, and further controls the tracking error signal. Then, the position of the objective lens is controlled perpendicularly to the recording track of the optical disk 501 so that the focal point of the laser beam follows the recording track.

The signal processing unit 504 performs digital signal processing on the input EFM signal and ADIP signal,
It reproduces and outputs compressed audio data and address information. The compressed audio data is sent to a RAM (random access memory) via a memory processing unit 505.
506 is temporarily stored.

After that, the stored compressed audio data is again stored in the memory processing unit 50 in response to a request from the decompression unit 507.
5 and decompressed in the decompression unit 507 to obtain the original digital audio signal. The decompressed digital audio signal is converted to DAC
At (digital / analog converter) 508, the audio signal is restored to an analog audio signal.

The spindle motor 509 rotates the optical disk 501 under the control of a spindle control unit 511 described later. The rotation speed of the spindle motor 509 is detected by the rotation speed detection unit 513 and output as an FG signal.

The spindle control unit 511 controls the rotation of the spindle motor 509 based on the target rotation speed from the system control unit 512 and the FG signal from the rotation speed detection unit 513.

The system control unit 512 includes a memory processing unit 5
The remaining amount of memory in the RAM 506 acquired via the CPU 05 and the FG signal output from the rotation speed detecting unit 513 are monitored, and a control signal corresponding to the remaining amount of memory and the FG signal is transmitted to the RF unit 503, the signal processing unit 504, Output to PU servo section 510 and spindle control section 511.

The control signal output to the RF unit 503, the signal processing unit 504, and the PU servo unit 510 is a reproduction control unit stop command SLP. Optical pickup 5
The PU servo unit 510 performs control so that the signal 02 can read the signal, and the read signal is written to the RAM 506 via the RF unit 503, the signal processing unit 504, and the memory processing unit 505, and the reproducing operation is performed.

On the other hand, when the reproduction control unit stop command SLP
In this case, the operations of the RF unit 503, the signal processing unit 504, and the PU servo unit 510 are stopped, and no signal is read from the optical disk 501.

Control signals output from the system control unit 512 to the spindle control unit 511 include a target rotation speed of the spindle motor 509 and a spindle control unit stop command SPSLP, and a spindle control unit stop command SP
When SLP is logic L, the spindle control unit 511 controls the spindle motor 509 to rotate at the target rotation speed.

On the other hand, the spindle control unit stop command SPSL
When P is logic H, the operation of the spindle control unit 511 is stopped, and the supply of the drive current to the spindle motor 509 is stopped. Therefore, the optical disk 501 is rotated by inertia, and the spindle motor 509 is rotated.
The number of rotations gradually decreases due to the shaft loss and windage loss. Here, this state is called a free run.

Here, detailed operations of the memory processing unit 505 and the system control unit 512, which are the core of the intermittent drive reproduction technique, will be described.

The audio data output from the signal processing unit 504 is compressed to about one fifth. Therefore, the transfer rate of the compressed audio data output to the decompression unit 507 may be about one fifth of the transfer rate of the compressed audio data input from the signal processing unit 504.

Since the capacity of the RAM 506 is limited, if compressed audio data is continuously input from the signal processing unit 504, the compressed audio data is
7, the input from the signal processing unit 504 causes the RAM 506 to not be able to store the input compressed audio data. Here, this state is called overflow.

Conversely, if a period during which no compressed audio data is input from the signal processing unit 504 continues, the RAM 50
The compressed audio data stored in the decompressor 6 decreases, and the compressed audio data that must be output to the decompressor 507 without interruption is insufficient. Here, this state is called an underflow.

When the RAM 506 is in an overflow or underflow state, the compressed audio data is not correctly transmitted to the decompression unit 507, and as a result, the audio signal is interrupted or stopped.

For this reason, the system control unit 512 monitors the remaining memory capacity of the RAM 506 via the memory processing unit 505, and when the remaining memory capacity becomes equal to or less than a predetermined threshold value TL, prepares for a reproducing operation. The control unit stop command SLP is set to logic L, and data reading from the optical disk 501 is started. When the remaining memory exceeds a predetermined threshold TH having a value larger than the threshold TL,
The system control unit 512 sets the reproduction control unit stop command SLP to logic H, and stops reading data from the optical disk 501.

By such processing, the system control unit 51
2 controls so that the remaining memory capacity is always maintained between the threshold values TL and TH so as not to underflow or overflow.

FIG. 6 is a block diagram showing a configuration of a loop filter for calculating an output signal of the spindle control unit 511.

A speed control filter 601 for inputting an error signal obtained by comparing an FG signal indicating the rotation speed of the spindle motor with a target rotation speed and outputting a signal multiplied by a certain constant, and a constant for the input error signal A loop filter is composed of a low-pass compensation filter 602 that integrates the signal multiplied by the integrator and outputs the integrated signal. A signal obtained by adding the output signals of the speed control filter and the low-pass compensation filter is used as the output signal of the loop filter. .

The speed control filter 601 outputs a signal proportional to the error signal, and generates a current for driving the spindle motor 509 according to the signal. However, since there is a loss of drive current due to iron loss, shaft loss, wind loss, etc. of the motor, the spindle motor 509 rotates at a rotational speed lower than the target rotational speed on average, and high rotational accuracy can be obtained only with the speed control filter. The required rotation control is difficult.

Therefore, by adding a low-frequency compensation filter 602 as shown in FIG. 6, a gain for a low-frequency component of an error signal caused by iron loss, shaft loss, windage, and the like is secured, and the driving current of the driving current is reduced. It tries to make up for the loss.

By forming a feedback loop using such a loop filter, it is possible to perform motor rotation control with high-performance rotation accuracy.

FIG. 7 is a timing chart of an intermittent drive reproduction operation in an optical disk device according to the prior art.

The horizontal axis is the time axis, and FIG.
Remaining memory REM in (b) is the system controller 5
12 to the RF unit 503, the signal processing unit 504, and the PU
Reproduction control unit stop command SL output to servo unit 510
P and (c) show the time transition of the spindle control unit stop command SPSLP output to the spindle control unit 511, and (d) shows the time transition of each of the FG signals indicating the rotation speed of the spindle motor 509.

In FIG. 7, in a section A in which data is read from the optical disk 501, the system control unit 512 logically issues a reproduction control unit stop command SLP to the RF unit 503, the signal processing unit 504, and the PU servo unit 510. L
Then, the spindle control unit 511 sets the target rotation speed to a reproduction speed at which data can be reproduced from the optical disk 501, and sets the spindle control unit stop command SPSLP to logic L.

As a result, the spindle motor 509 rotates at the reproduction speed, and the PU servo unit 510 performs control so that the optical pickup 502 can read a signal from the optical disk 501. The read signal is transmitted to the RF unit 503, the signal processing unit 504, Since data is written to the RAM 506 via the memory processing unit 505, the remaining memory REM increases.

In the section A, when the system control unit 512 determines that the remaining memory amount REM exceeds the threshold value TH, the reproduction control unit stop command SLP and the spindle control unit stop command S
Both PSLPs are set to logic H.

As a result, in the following sections B, C and D, data reading from the optical disk 501 is stopped, so that the remaining memory REM decreases in accordance with the output of the compressed audio data to the decompression unit 507.

In the section B, the spindle motor 509 to which the drive current is no longer supplied from the spindle control unit 511
Becomes free-run, and the rotation speed gradually decreases.

The system control unit 512 includes a rotational speed detecting unit 51.
3 is monitored, and when it is determined from the FG signal that the spindle motor 509 has fallen below the predetermined standby speed, the spindle control unit stop command SPSL
P is set to logic L, and the target rotation speed is set to the spindle control unit so that the spindle motor 509 rotates at the standby speed.

Thus, in the following section C, the spindle control unit 511 keeps the spindle motor 509 rotating at the standby speed.

In the section C, the system control unit 512 monitors the remaining memory REM, and determines that the remaining memory REM is equal to the threshold T.
If L is smaller than L, the target rotation speed is set to the spindle control unit 511 such that the spindle motor 509 rotates at the reproduction speed.

That is, in the section D, the spindle motor 509 is prepared in preparation for reading data from the optical disc 501.
Is a section for accelerating to the reproduction speed.

In section D, system control unit 512
Indicates that the spindle motor 309 has reached a reproduction speed at which data can be read from the optical disc 501.
When it is determined from the G signal, the reproduction control unit stop command SLP is set to logic L, data reading from the optical disk 501 is resumed, and the obtained compressed audio data is stored in the RAM 5.
06. This operation allows the remaining memory REM
Starts to increase again.

As described above, in the sections B, C, and D in which data is not reproduced from the optical disk 501, the RF unit 5
03, the signal processing unit 504, the operation of the PU servo unit 510 is stopped, and in the section B where the rotation speed of the spindle motor 509 decreases to the standby speed, the spindle motor 5
Since the supply of the current to the power supply 09 is stopped and the operation of the spindle control unit 511 is stopped, the redundant reproduction operation can be stopped, and the power saving of the optical disk device can be realized.

[0048]

In the rotation control device according to the prior art, the target rotation speed of the spindle motor 509 is changed in accordance with the remaining memory amount REM in the intermittent drive reproduction operation. The rotation speed is rotated at a reproduction speed at which the reproduction operation can be performed, and when the reproduction operation is stopped, the rotation is performed at a standby speed which is significantly lower than the rotation speed at the time of the reproduction operation. With this intermittent driving operation, the driving current supplied to the spindle motor 509 was reduced, and a great effect was achieved in reducing power consumption.

Here, the stability of the feedback system in the motor rotation control depends on the gain margin and the phase margin of the open loop characteristic. If these cannot be ensured, the feedback system becomes unstable, and the response waveform of the step response becomes unstable. Overshoot occurs.

Since each processing section of the feedback system has a finite dynamic range, each output signal has a possibility of being saturated.

When the output signal is not saturated, the input and output are linear, so that the gain margin and phase margin as designed are ensured, and the feedback system behaves stably. However, when the output signal is saturated, the input and output are nonlinear. As a result, the gain margin and the phase margin as designed are not secured, and there is a possibility that stable behavior may not be achieved.

According to the prior art, when a large step of an error signal is input, the speed control filter 60
1 outputs a large high-frequency component signal, and this output signal is likely to be saturated.

In this case, equivalently, the speed control filter 60
1 lowers the high-frequency compensation, resulting in a state similar to that of the gain margin and phase margin of the open-loop characteristic being reduced, resulting in reduced feedback system stability and overshoot.

The above operation will be specifically described with reference to FIG.

FIG. 8 is a signal waveform diagram for explaining the operation of the loop filter in the conventional optical disk device.

The horizontal axis is the time axis, (a) is the target rotation speed of the spindle motor, (b) is the actual rotation speed, (c) is the drive signal output by the loop filter, and (d) is the ideal which does not saturate. (E) is a signal waveform showing the integral value of the low-pass compensation filter 602 in the integrator.

In section P, the spindle motor is steadily rotated at the standby speed, but in section Q, the target rotation speed (a) is set to the reproduction speed.

In an ideal loop filter that does not saturate,
A drive signal (d) corresponding to the input error signal is output to control the spindle speed to the target speed without overshooting. However, in actuality, since the dynamic range of the feedback system is finite, the output is limited. The signal (c) is saturated, the spindle motor is not sufficiently accelerated, and the rotation speed (b) does not immediately reach the target rotation speed (a).

Therefore, in the section Q, the error signal that does not easily decrease is integrated by the integrator of the low-pass compensation filter 602, and the integrated value (e) increases rapidly.

After that, even in the section R after the rotation speed (b) rises and coincides with the target rotation speed (a), the loop filter continues to output the saturated drive signal (c) under the influence of the large integral value. That is, the rotation speed (b) greatly exceeds the target rotation speed (a), and an overshoot occurs.

In the section R, since the polarity of the error signal is inverted, the integral value (e) of the low-pass compensation filter 602 starts to decrease, but the saturation of the output signal (c) of the loop filter is not immediately eliminated.

When the value of the integral value (e) has decreased to some extent, the saturation of the output signal (c) of the loop filter has been eliminated, and the drive signal (c) finally begins to decrease and the rotational speed (b) of the spindle motor also decreases. It decreases and converges to the target rotational speed (a).

Then, in the subsequent section S, the spindle motor rotates at a steady speed at the reproduction speed which is the target rotation speed.

As described above, every time the rotational speed is suddenly increased from the standby speed to the operating speed, the high-frequency compensation of the speed control filter 601 is equivalently reduced, and an overshoot of the rotational speed occurs. In addition, it takes a long time until the rotation speed is settled at the target rotation speed, and wasteful drive current is consumed, so that the effect of reducing power consumption by intermittent drive regeneration is reduced.

In addition, the overshoot causes the rotational speed to fluctuate significantly up and down, causing a problem that undulation-like noise is generated from the spindle motor.

The present invention has been made in view of such a problem, and reduces the overshoot of the number of revolutions, shortens the settling time, and reduces power consumption and noise (noise) as compared with the conventional rotation control device. It is an object of the present invention to provide a rotation control device capable of reducing the number of rotations.

[0067]

In order to achieve the above object, a rotation control device according to a first aspect of the present invention is a rotation control device having a feedback loop for controlling a motor to a predetermined rotation speed. A low-pass compensation filter for compensating for the gain of a low-frequency component of the signal in the feedback loop, and saturation detection means for detecting saturation of the signal in the feedback loop, wherein the saturation detection means It is characterized in that the gain of the low-pass compensation filter is reduced.

A rotation control device according to a second aspect of the present invention is a rotation control device including a feedback loop for controlling a motor to a predetermined rotation speed, wherein a low-frequency component of a signal in the feedback loop is reduced. A low-pass compensation filter for compensating a gain; and a saturation detection unit for detecting saturation of a signal in the feedback loop, wherein processing of the low-pass compensation filter is stopped according to an output of the saturation detection unit. It is assumed that.

[0069]

Embodiments of the present invention will be described below with reference to the drawings. The following description is based on FIG.
Mainly describes the internal configuration (loop filter) of the spindle control unit 511 in the first embodiment. The rotation control device includes a feedback loop including a spindle motor 509, a rotation speed detection unit 513, and a spindle control unit 511. is there.

(Embodiment 1) FIG. 1 is a block diagram showing a schematic configuration of a rotation control device according to Embodiment 1 of the present invention.

As shown, the rotation control device according to the first embodiment of the present invention includes a speed control filter 101, a low-frequency compensation filter 102 including a gain A103, a gain B104, a switch circuit 105, and an integrator 106.
And a saturation detecting means 107.

The speed control filter 101 outputs a signal obtained by multiplying an error signal obtained by comparing the FG signal indicating the rotation speed of the spindle motor with the target rotation speed by a constant, and matches the rotation speed of the spindle motor with the target rotation speed. It works as follows.

The gain A 103 and the gain B 104 multiply the input error signals by different constants and output the same, and input the respective output signals to the switch circuit 105. Here, the gain B104 is smaller than the gain A103.

The switch circuit 105 is connected to the saturation detecting means 10.
When the saturation detection signal output from 7 is logic L, the switch is connected to the a side to output the input signal from the gain A103, and when the saturation detection signal is logic H, the switch is connected to the b side to gain By outputting the input signal from B104, the output signal of switch circuit 105 is switched.

The signal output from switch circuit 105 is integrated in integrator 106, and the integrated value is output.

This output signal becomes the output of the low-pass compensation filter 102, and compensates for the gain of the low-pass component of the error signal to compensate for the loss of the driving current due to iron loss, shaft loss, wind loss, etc. of the spindle motor. .

The output signals of the speed control filter 101 and the low-pass compensation filter 102 are added by an adder and output as a drive signal.

The saturation detecting means 107 compares the drive signal with a predetermined threshold value. If the drive signal is larger than the predetermined threshold value, the saturation detection signal, which is an output signal, is set to logic H. If smaller, the saturation detection signal is set to logic L
And

As described above, the saturation detecting means 107 detects the saturation state of the drive signal generated from the speed control filter 101 and the low-pass compensation filter 102, and sends the saturation detection signal to the switch circuit 105 of the low-pass compensation filter 102. Output.

FIG. 2 is a signal waveform diagram showing signals for explaining the operation of the present embodiment. The horizontal axis is a time axis, and FIG.
Is the target rotational speed of the spindle motor, (b) is the actual rotational speed, (c) is the drive signal obtained by adding the output signals of the speed control filter 101 and the low-pass compensation filter 102, and (d) is the drive by the saturation detecting means 107. A predetermined threshold to compare with the signal,
(E) is a saturation detection signal, and (f) is a signal waveform showing a temporal transition of each integrated value of the integrator 106.

In the section E, the target rotation speed (a) of the spindle motor is set to the standby speed, so that the rotation speed is low and the drive signal (c) is relatively small.

Further, since the driving is performed at a low rotation speed, the loss of the driving current due to the shaft loss or the like is small, so that the integral value (f) of the integrator 106 keeps outputting a considerable value.

Further, in section E, since the rotation speed of the spindle motor and the target rotation speed are in a steady state, the error signal is almost zero, so that the output of the speed control filter 101 becomes almost zero. Most of the drive signal is occupied by the output signal of the low-pass compensation filter 102.

At this time, since the drive signal has a value smaller than the threshold value (d), the saturation detection signal (e) becomes logic L.
The switch of the switch circuit 105 is connected to the a side, the output signal of the gain A103 is integrated by the integrator 106, and the integrated value becomes the output of the low-pass compensation filter 102.

In the transition from the section E to the section F, the target rotation speed (a) is set to a rotation speed at which the reproducing operation from the optical disk can be performed, so that the error signal sharply increases. The speed control filter 101 attempts to output a signal proportional to the error signal, but cannot output a desired value because the error signal is large, and the output signal is saturated at a certain value.

Therefore, the drive signal, which is an addition signal of the output of the speed control filter 101 and the output of the low-pass compensation filter 102, exceeds the threshold value (d), and the saturation detection signal (e) becomes logic H.

In response to the change of the saturation detection signal (e) from the logic L to the logic H, the switch circuit 105 switches the switch from the a side to the b side, and changes the signal input to the integrator 106 from the output of the gain A103. Switching to the output of the gain B104, the gain of the low-frequency compensation filter 102 is set low. By doing so, it is possible to prevent the integrated value (f) of the integrator 106 from rapidly increasing due to the input large error signal.

Subsequently, the spindle motor is accelerated by the saturated drive signal to increase the rotation speed (b), and accordingly, the error signal decreases, the output of the speed control filter 101 decreases, and the output of the low-pass compensation filter 102 decreases. Becomes smaller than the threshold value (d), and the saturation detection signal becomes logic L.

Therefore, the switch of the switch circuit 105 is connected to the side a again, and the gain of the low-frequency compensation filter 102 is set large.

In the following section G, the low-pass compensation filter 1
Although the gain of 02 increases, the integrated value (f) does not increase sharply because the input error signal decreases, and no large signal disturbance occurs in the drive signal.

During this time, the rotational speed (b) of the spindle motor increases and the error signal continues to decrease.

The rotation speed (b) is equal to the target rotation speed (a).
Since the error signal becomes almost zero when the value of と 一致 と と と と, the output of the speed control filter 101 becomes almost zero, and the integral value (f) of the integrator 106 keeps a constant value. It becomes the output signal of the band compensation filter 102.

Here, the loss of the driving current due to iron loss, shaft loss, windage loss, etc., increases as the rotation speed of the spindle motor increases. In this case, the integrated value held by the integrator 106 during steady rotation differs.

In the section H in which the target rotation speed (a) and the rotation speed (b) are coincident, the spindle motor is in a steady rotation, and this state is continued until the target rotation speed (a) is changed. Become.

As described above, the speed control filter 101
, Gain A103, gain B104, switch circuit 1
05, low-pass compensation filter 1 composed of integrator 106
02 and the rotation control device including the saturation detection means 107, even when a large error signal is input, to detect the saturation of the output drive signal in accordance with the input and reduce the gain of the low-frequency compensation filter 102. By the integrator 10
6 is suppressed, and the low-pass compensation filter 1
02 can reduce the influence of the output signal on the drive signal and reduce the overshoot of the rotational speed.

In the present embodiment, two gains are switched. However, the same effect can be obtained even if three or more gains are provided and the gains are switched according to the level of the drive signal. .

(Embodiment 2) Hereinafter, a rotation control device according to Embodiment 2 of the present invention will be described with reference to FIGS.

FIG. 3 is a block diagram showing a schematic configuration of the rotation control device according to the present embodiment.

As shown, the rotation control device according to the present embodiment includes a speed control filter 301 and a gain 30.
3. Low-pass compensation filter 30 composed of integrator 304
2 and a saturation detection means 305.

The speed control filter 301 and the saturation detecting means 3
05 is the speed control filter 10 according to the first embodiment.
1, the same as the respective saturation detection means 107, and a detailed description is omitted.

The gain 303 outputs a signal obtained by multiplying the input error signal by a constant to an integrator 304. The integrator 304 outputs a logic L based on the saturation detection signal output from the saturation detection means 305.
In the case of (1), the output signal of the gain 303 is integrated to output an integrated value. When the saturation detection signal is logic H, the operation of integration is stopped, the integrated value immediately before the stop is held, and the value is continuously output.

The output of the integrator 304 is the low-pass compensation filter 3
02, which is added to the output signal of the speed control filter 301 by the adder to form a drive signal.

FIG. 4 is a signal waveform diagram showing signals for explaining the operation of the present embodiment. The horizontal axis is a time axis, (a) is the target rotation speed of the spindle motor, and (b) is the actual rotation speed. (C) is a drive signal obtained by adding the output signals of the speed control filter 301 and the low-pass compensation filter 302, (d) is a predetermined threshold value to be compared with the drive signal by the saturation detection means 305,
(E) is a saturation detection signal, and (f) is a signal waveform showing a temporal transition of each of the integrated values of the integrator 304.

In section J, the target rotation speed (a) of the spindle motor is set to the standby speed, so that the rotation speed is low and the drive signal (c) is relatively small.

Further, since the driving is performed at a low rotation speed, the loss of the driving current due to the shaft loss or the like is small, so that the integral value (f) of the integrator 304 keeps outputting a considerable value.

Further, in section J, the error signal is almost zero and the output signal of the speed control filter 301 is also almost zero because the spindle motor is in a steady rotation, and most of the drive signal is in the low-frequency compensation range. The output signal of the filter 302 is occupied.

At this time, since the drive signal has a value smaller than the threshold value (d), the saturation detection signal (e) becomes logic L, and the integrator 304 inputs the output signal of the gain 303 and performs integration. The integrated value (f) is applied to the low-pass compensation filter 3
02 output signal.

In the transition from the section J to the section K, the target rotation speed (a) is set to a rotation speed at which the reproducing operation from the optical disk is possible, so that the error signal sharply increases. However, since the error signal is large, a desired value cannot be output, and the output signal is saturated at a certain value.

Therefore, the drive signal, which is an addition signal of the output of the speed control filter 301 and the output of the low-pass compensation filter 302, exceeds the threshold (d), and the saturation detection signal (e) becomes logic H.

In response to the change of the saturation detection signal (e) from logic L to logic H, the integrator 304 stops the integration operation, and holds the integration value (f) while maintaining the integration value (f) immediately before the stop. ), The low-pass compensation filter 302
Stops the processing operation.

As described above, it is possible to easily avoid a sudden increase in the integrated value (f) of the integrator 304 due to a large input error signal.

Subsequently, the spindle motor is accelerated by the saturated drive signal to increase the rotation speed (b), and accordingly, the error signal decreases, the output of the speed control filter 101 decreases, and the output of the low-pass compensation filter 302 decreases. Becomes smaller than the threshold value (d), and the saturation detection signal becomes logic L.

Therefore, the integration operation of the integrator 304 starts again, the error signal is integrated into the integrated value immediately before the stop, and the processing of the low-pass compensation filter 302 operates.

In the section L, the low-pass compensation filter 302
Is started again, but the integrated value (f) does not increase sharply because the input error signal decreases,
No large signal disturbance occurs in the drive signal. During this time, the rotation speed (b) of the spindle motor also increases, and the error signal keeps gradually decreasing.

The rotation speed (b) is equal to the target rotation speed (a).
Since the error signal becomes almost zero in the vicinity, the output of the speed control filter 301 also becomes almost zero, and the integrated value (f) of the integrator 304 also outputs a constant value. An output signal of the band compensation filter 302.

Here, the loss of drive current due to iron loss, shaft loss, wind loss, etc., increases as the rotation speed of the spindle motor increases. The integral value held by the integrator 304 during the steady rotation differs from that in the case of rotation.

In the section M in which the target rotation speed (a) and the rotation speed (b) coincide with each other, the spindle motor becomes a steady rotation, and this state is continued until the target rotation speed (a) is changed. .

As described above, the speed control filter 301
Even if a large error signal is continuously input for a long time, the output is adjusted in accordance with the rotation control device including the low-pass compensation filter 302 including the gain 303 and the integrator 304, and the saturation detection unit 305. By detecting the saturation of the drive signal obtained and stopping the processing operation of the low-pass compensation filter 102, it is possible to eliminate a rapid increase in the integral value of the integrator 304, reduce the overshoot of the rotational speed, and reduce By stopping the processing operation of the band compensation filter 102, power consumption can be reduced.

In the case of the rotation control device according to the first embodiment of the present invention, the error signal input to the low-pass compensation filter is large, and if the error signal continues for a long time, the saturation of the drive signal is detected and the gain of the low-pass compensation filter is detected. Even if the value is changed to lower, the integral value of the integrator may become abnormally large, and it may be impossible to avoid overshoot of the rotation speed of the spindle motor.

However, in the case of the rotation control device according to the second embodiment, at the moment when the error signal becomes large and the drive signal is saturated, the saturation detecting means stops the processing operation of the low-pass compensation filter, and the integrated value immediately before the stop is obtained. Is maintained, the integral value does not become abnormally large, overshooting of the rotation speed of the spindle motor can be avoided, and power saving can be achieved by stopping the operation of the low-pass compensation filter.

In the first embodiment of the present invention,
Although the gain B104 is set to be smaller than the gain A103, the same effect can be obtained by setting the gain of the gain B104 to zero.

In the first and second embodiments of the present invention, the gain of the low-pass compensation filter is switched by detecting the saturation of the drive signal. However, signals in a feedback loop other than the drive signal are used. The same effect can be obtained.

Further, in Embodiments 1 and 2 of the present invention, only one threshold value is provided, and when the drive signal is larger than the threshold value, the saturation detection signal is set to logic H.
If the saturation detection signal is set to logic H when the drive signal exceeds the range sandwiched by the two threshold values, not only the overshoot of the rotation speed during acceleration of the spindle motor, but also
Undershoot during deceleration can also be reduced.

Further, in Embodiments 1 and 2 of the present invention, the same effect is obtained regardless of whether the speed control filter, the low-pass compensation filter, and the saturation detecting means are constituted by analog circuits or digital circuits. can get.

Further, in the first and second embodiments of the present invention, the case where the intermittent drive reproduction is performed has been described. However, the same effect can be obtained when the spindle motor is accelerated from the stopped state to the target rotational speed. .

[0126]

According to the first aspect of the present invention, there is provided a rotation control device provided with a feedback loop for controlling a motor to a predetermined rotation speed, wherein a low-frequency component of a signal in the feedback loop is provided. A low-pass compensation filter for compensating the gain of the signal, and saturation detection means for detecting the saturation of the signal in the feedback loop. By lowering the gain of the low-pass compensation filter according to the output of the saturation detection means, Since the integrated value of the integrator inside the low-pass compensation filter does not suddenly increase even when the rotational speed changes,
It is possible to reduce the overshoot of the rotation speed, thereby shortening the settling time of the rotation speed and reducing the power consumption, and reducing the noise such as undulation generated from the spindle motor. it can.

Further, according to the rotation control device according to the second aspect of the present invention, there is provided a rotation control device having a feedback loop for controlling a motor to a predetermined rotation speed, wherein a low-frequency component of a signal in the feedback loop is provided. A low-pass compensation filter for compensating the gain of the signal, and saturation detection means for detecting the saturation of the signal in the feedback loop. By stopping the processing of the low-pass compensation filter in accordance with the output of the saturation detection means, Even when the target rotational speed changes, the overshoot of the rotational speed can be reduced by retaining the integral value of the integrator inside the low-pass compensation filter, and as a result, the settling time of the rotational speed is shortened and consumption is reduced. It is possible to reduce power consumption, reduce noise such as waviness generated from the spindle motor, The effect of reducing the power consumption by the management stop can also be expected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a rotation control device according to a first embodiment of the present invention.

FIG. 2 is a signal waveform diagram showing an operation of the rotation control device.

FIG. 3 is a block diagram showing a configuration of a rotation control device according to a second embodiment of the present invention.

FIG. 4 is a signal waveform diagram showing an operation of the rotation control device.

FIG. 5 is a block diagram showing a configuration of an optical disc device provided with a rotation control device according to a conventional technique.

FIG. 6 is a block diagram showing a configuration of a rotation control device according to a conventional technique.

FIG. 7 is a signal waveform diagram showing an operation of a rotation control device according to a conventional technique.

FIG. 8 is a signal waveform diagram showing an operation of a loop filter according to a conventional technique.

[Explanation of symbols]

 101, 301, 501 Speed control filter 102, 302, 502 Low-pass compensation filter 107, 305 Saturation detection means

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasuhiro Yoshioka 1006 Kadoma Kadoma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. LL01

Claims (2)

[Claims] 1. A rotation control device comprising a feedback loop for controlling a motor to a predetermined rotation speed, comprising: a low-pass compensation filter for compensating a gain of a low-frequency component of a signal in the feedback loop; A rotation detection device for detecting saturation of a signal inside the rotation control device, wherein a gain of the low-pass compensation filter is reduced according to an output of the saturation detection device. 2. A rotation control device comprising a feedback loop for controlling a motor to a predetermined rotation speed, comprising: a low-pass compensation filter for compensating a gain of a low-frequency component of a signal in the feedback loop; A rotation control device comprising: a saturation detection unit configured to detect saturation of a middle signal, wherein processing of the low-pass compensation filter is stopped according to an output of the saturation detection unit.