JPS63316682A - Stop controller for spindle motor - Google Patents

Abstract

PURPOSE:To control stopping quickly and exactly, by producing the rotational frequency signal of a level according to rotational frequency, and by controlling the stopping based on the comparing output of a level comparator and a window comparator for setting said signal to be comparing input. CONSTITUTION:A disc 1 is rotationally driven by a spindle motor 2, and its recording informations are read by an optical pick-up 3. The read output of the pick-up 3 is fed to a video information demodulation system 5 and a digital information demodulation system 6 via an RF amplifier 4. The moving position of the pick-up 3 is detected by a detector 11, and is fed to a system controller 9. Besides, a rotational frequency detection circuit 13 is set, and this rotational frequency signal is fed to said controller 9 via a level comparator 14 and a window comparator 15. As a result, by the controller 9, the rotating direction of the motor 2 is discriminated, and it is discriminated that the motor is not in a stopping state, and the stopping of the motor 2 is controlled via a motor drive circuit 12.

Description

TECHNICAL FIELD The present invention relates to a stop control device for a spindle motor, and more particularly to a stop control device for a spindle motor that rotates at high speed.

BACKGROUND ART Recently, as shown in FIG.
CM (Pulse Code Modulation
The first area on the inner circumferential side (hereinafter referred to as C
A second area (hereinafter referred to as video area) on the outer circumferential side where a video signal subjected to frequency modulation processing and an audio signal converted into PCM are multiplex recorded.
Composite discs in which information is recorded in areas divided into two areas have been developed and are being commercialized.

By the way, video signals contain higher frequency components than PCM signals, and when recording signals in the video area, it is necessary to increase the rotational speed of the disc compared to when recording in the CD area. Naturally, during performance, the rotational speed of the disc must be much higher in the video area than in the CD area. The rotational speed is approximately several hundred rpm in the CD area 1a, whereas in the video area 1b, the rotational speed is very high, 2,000-plus rpm at the innermost periphery of the area, and 1,000-plus rpm at the outermost periphery. Become. When stopping the spindle motor that drives the rotation of the composite disk when playing a video area with extremely high rotational speeds, it is necessary to stop the spindle motor quickly and reliably in order to smoothly transition to the next mode. This is necessary.

Conventionally, video discs have been known to require extremely high rotational speeds, similar to the video area of composite discs, and a performance device for this video disc has a frequency generator (FG) that is linked to a spindle motor. The spindle motor is configured to stop by monitoring changes in the rotational speed of the spindle motor based on the output of the frequency generator and applying a brake according to the rotational speed.

However, frequency generators are expensive, and using an expensive frequency generator to control the stoppage of a spindle motor becomes a factor that prevents cost reduction of the entire system.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a spindle motor that can contribute to reducing the cost of the entire system by enabling quick and reliable stop control without using a frequency generator. The purpose is to provide a stop control device.

A stop control device for a spindle motor according to the first invention of the present application includes a rotation speed detection means for generating a rotation speed signal at a level corresponding to the rotation speed of the spindle motor, and a signal level of the rotation speed signal at a reference level corresponding to zero rotation speed. a level comparator that detects that the signal level of the rotation speed signal has fallen below the reference level, and a window comparator that detects that the signal level of the rotation speed signal is within a range of upper and lower reference levels with the reference level as the center level, The stop control of the spindle motor is performed based on the detection outputs of the window comparators and the detection outputs of the window comparators.

A spindle motor stop control device according to a second invention of the present application includes a rotation speed detection means for generating a rotation speed signal at a level corresponding to the rotation speed of the spindle motor, and a signal level of the rotation speed signal at a reference level corresponding to zero rotation speed. A window comparator detects that the signal level of the rotation speed signal falls within a range of upper and lower reference levels with the center level being the center level, and a window comparator that detects that the signal level of the rotation speed signal falls below a reference level that is set lower than the lower reference level. The spindle motor is configured to have a level comparator and perform stop control of the spindle motor based on the detection outputs of the window comparator and the level comparator.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a disc player having a spindle motor stop control device according to the present invention. In the figure, a disk 1 is rotationally driven by a spindle motor 2, and recorded information is read by an optical pickup 3. The pickup 3 includes a laser diode as a light source, an optical system including an objective lens, a 4-split photodetector that receives reflected light from the disk 1, and a direction of the optical axis of the objective lens with respect to the information recording surface of the disk 1. A focus actuator for controlling the position, a tracking actuator for controlling the position of the main beam spot emitted from the pickup 3 in the recording track in the disk radial direction, and the like are built-in. The read output of the pickup is supplied to a video information demodulation system 5 and a digital information demodulation system 6 via an RF amplifier 4.

In the video information demodulation system 5 , the reproduced RF signal from the RF amplifier 4 is demodulated into a video signal by a video demodulation circuit 50 and then supplied to a time axis correction circuit 51 . The time axis correction circuit 51 is composed of, for example, a variable delay element such as a CCD, and is configured to perform time axis correction by changing the amount of delay of the element in accordance with a control signal from the time axis control circuit 52. . The time axis control circuit 52 outputs the oscillation output of a crystal oscillator (VCXO) 54 that oscillates in synchronization with the horizontal synchronization signal separated from the video signal by the synchronization separation circuit 53 and its frequency-divided output, and the time axis correction circuit 51. The structure is such that a control signal is generated in accordance with the phase difference between the horizontal synchronization signal and the color burst signal in the video signal passed through the video signal. The video signal subjected to time axis correction by the time axis correction circuit 51 is supplied to the video output terminal 8 via the video signal processing circuit 55. The video signal processing circuit 55 performs various processes such as video muting for inhibiting the output of video signals and character insertion.

On the other hand, the digital information demodulation system 6 is provided with a changeover switch 60 that is switched depending on the area to be played (CD area and video area) when playing a composite disc, and this switch 6o is set to the a side when playing the CD area. When the video area is played, it is on the b side, and the switching is performed in response to a switching command issued from the system controller 9, which will be described later. The PCM audio signal recorded in the CD area and the video area is, for example, E F M (Eight
t t.

When playing the CD area, the reproduced EFM signal passes through an equalizer circuit 61 and an amplifier 62, and then is supplied to a demodulation/correction circuit 66 via a changeover switch 6o. On the other hand, when playing the video area, the EFM extraction circuit 63 extracts the reproduced RF signal.
The reproduced EFM signal extracted in is supplied to a demodulation/correction circuit 66 via a changeover switch 60 after passing through an equalizer/riser circuit 64 and an amplifier 65 .

The demodulation/correction circuit 66 demodulates the EFM signal into R
In addition to writing to a memory such as AM (not shown), RA is written based on the reference clock from the reference clock generator 67.
It controls M, exchanges data, performs deinterleaving, and performs error correction using parity contained in the data. The digital audio signal demodulated and corrected by the demodulation/correction circuit 66 is processed by an audio signal processing circuit 68 consisting of a D/A (digital/analog) converter, a deglitcher, etc., and then sent to the left and right channel audio output terminals. 10L, IOR
is supplied to

A position detector 11 is provided near the movement path of the pickup 3 in the disk radial direction, and detects the movement position of the main beam spot emitted from the pickup 3 in the disk radial direction. The position information is supplied to the system controller 9. Based on this position information, it is possible to detect that the main beam spot has arrived near the boundary between the CD area and the video area. System controller 9
consists of a microcomputer, which exchanges data with each section such as the video information demodulation system 5 and the digital information demodulation system 6 via the path line 12, and provides switching commands to the changeover switch 60 in the digital information demodulation system 6. generation, and drive control of the spindle motor 2 via the motor drive circuit 12.

A rotation speed detection circuit 13 is provided to detect the rotation speed of the spindle motor 2. This rotation speed detection circuit 13
As shown in FIG. 2, there is a bridge circuit consisting of resistors Ra-Re with the spindle motor 2 as one side, and resistors R+ to detect the potential difference generated between A-8 in response to the back electromotive force of the spindle motor 2. It consists of a differential amplifier consisting of R4 and an operational amplifier OP, and generates a rotation speed signal at a level corresponding to the rotation speed of the spindle motor 2 based on the back electromotive force generated in the spindle motor 2. This rotational speed signal is sent to a level comparator 14 and a window comparator 15.
is supplied to As shown in FIG. 3, the level comparator 14 has a reference level VTI-10 (for example, zero level) corresponding to the zero rotation speed of the spindle motor 2, and when the spindle motor 2 is decelerated, the signal level of the rotation speed signal is A detection output is generated when the voltage falls below the reference level VTHo.

On the other hand, the window comparator 15 is at the reference level VT)
-10 as the center level, and has an upper limit reference level V1-H1 and a lower limit reference level VTH2, and the signal level of the rotation speed signal is the upper limit reference level VTHI and the lower limit reference level VT.
A detection output is generated when it falls within the range of H2. Each output of the level comparator 14 and the window comparator 15 is supplied to the system controller 9.

Based on the output of the level comparator 14, the system controller 9 controls the rotation direction (positive direction/
In addition, based on the output of the window comparator 15, it can be determined whether the spindle motor 2 has substantially stopped. That is, in FIG. 3, region A is a forward rotation region, regions B and C are stop regions, and region 3 is a reverse rotation region. and,
The system controller 9 performs stop control of the spindle motor 2 via the motor drive circuit 12 based on these determination results.

Next, a control procedure executed by the processor of the system controller 9 when the spindle motor 2 is stopped will be described according to the flowchart of FIG. 4.

In a composite disc, when a stop command is issued during playback of a video area, for example, the processor first determines whether or not the spindle motor 2 is in the forward rotation area A based on the output of the level comparator 14 (step S1). If it is in the forward rotation region A, the motor drive circuit 1 applies a reverse brake to the spindle motor 2 by applying a large drive voltage of negative polarity to the spindle motor 2.
2 (step S2). Next, it is determined whether the spindle motor 2 is in the reverse rotation region based on the outputs of the level comparator 14 and the window comparator 15 (step S3), and if it is in the reverse rotation region,
The motor drive circuit 12 is controlled to apply a forward rotation brake to the spindle motor 2 by applying a small drive voltage of positive polarity to the spindle motor 2.
Tsubu S4). If it is determined in step S1 that it is not in the normal rotation region A, the process moves to step S3. Further, if it is determined in step S3 that the rotation region is not in the reverse rotation region, the process moves to step S5.

Next, by monitoring the output of the window comparator 15, it is determined whether the spindle motor 2 is in the stop area B or C. If it is in the stop area B or C, the spindle motor 2 is By lowering the power line to the ground level and shorting the spindle motor 2, the motor drive circuit 12 is controlled to apply a dynamic brake to the spindle motor 2.
At the same time, a built-in timer for a predetermined time T is started (step S7). Thereafter, it is determined again whether the spindle motor 2 is in the stop area B or C (step S8), and if it is within the stop area, it is then determined whether the predetermined time T has elapsed or not (step S9). , the stop control of the spindle motor 2 ends when a predetermined time T has elapsed within the stop region. As a result, the spindle motor 2 stops. If it is determined in step S5 and step s8 that it is not the stop area B or C, step S1
Return to

In this way, the level comparator 1 receives the rotation speed signal at a level corresponding to the rotation speed of the spindle motor 2 as a comparison input.
By determining the rotational state of the spindle motor 2 based on the comparative output of the window comparator 15 and the comparison output of the window comparator 15, and controlling the stoppage of the spindle motor 2 based on the determination result, the video area of a composite disk with a particularly high rotational speed can be controlled. Even if a command to stop the spindle motor 2 is issued during a performance, the spindle motor 2 can be stopped quickly and reliably without using an expensive frequency generator.

In addition, in the first invention of the present application described above, the reference level of the level comparator 14 is set to the reference level VT)-1o corresponding to the zero rotation speed of the spindle motor 2, and the upper reference level VTHI of the window comparator 15 is set with this as the center level. and the lower limit reference level VTH2 was set, but
As the reference level fluctuates due to constant changes due to the temperature of circuit elements, the relative level relationship between the reference level VTHo and the upper limit reference level VTHI and the lower limit reference level VTH2 changes, and the upper limit reference level VTHI and the lower limit reference level VTH2 change. Reference level V due to narrow range
It is possible that THo is outside the range. In such a case, stop control of the spindle motor 2 cannot be performed accurately.

Therefore, in the second invention of the present application, as shown in FIG.
The upper limit reference level VTHI and lower limit reference level kVTH2 of the window comparator 15 are set around the zero level corresponding to the zero rotation speed of the spindle motor 2, and the reference level VTI-13 of the level comparator 14 is further set as the lower limit reference level of the window comparator 15. VT)-12
The value is greater than the absolute value of -16 and is lower by a level that allows fluctuations in the reference level due to temperature, etc. (lVTH3l-1VT+
21>IVT)-121) The stop control of the spindle motor 2 can be accurately performed without being affected by fluctuations in the reference level due to temperature or the like. In this case as well, stop control of the spindle motor 2 is performed by the processor of the system controller 9 according to the procedure shown in the flowchart of FIG.

As described in detail, the spindle motor stop control device according to the present invention includes a level comparator that generates a rotation speed signal at a level corresponding to the rotation speed of the spindle motor and uses this rotation speed signal as a comparison input. By determining the rotational state of the spindle motor based on the comparison output of the window comparator and the comparison output of the window comparator, and controlling the stoppage of the spindle motor based on the determination result, the spindle motor can be stopped, especially during performances at extremely high rotational speeds. Even when a stop command is issued, the spindle motor can be stopped quickly and reliably using an inexpensive circuit without using an expensive frequency generator, contributing to lower costs for the entire system.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the configuration of a disc player having a spindle motor stop control device according to the present invention, FIG. 2 is a circuit diagram showing an example of the configuration of the rotation speed detection circuit in FIG. 1, and FIG. FIG. 4 is a diagram showing the relationship between the reference level of the level comparator and the upper and lower reference levels of the window comparator according to the first invention of the present application;
FIG. 5 is a flowchart showing the control procedure when the spindle motor is stopped, which is executed by the processor of the system controller in FIG. 1, and FIG. FIG. 6 is a diagram showing the relationship between levels, and is a diagram showing the division of recording areas of a composite disc. Explanation of symbols of main parts 1...Composite disc

Claims (4)

[Claims] (1) A stop control device for a spindle motor that rotationally drives an information recording disk, comprising a rotation speed detection means for generating a rotation speed signal having a level corresponding to the rotation speed of the spindle motor, and a signal level of the rotation speed signal. a level comparator for detecting that the rotation speed signal has fallen below a reference level corresponding to the zero rotation speed of the spindle motor, and a signal level of the rotation speed signal falling within a range of upper and lower reference levels with the reference level as a center level. A stop control device for a spindle motor, comprising: a window comparator that detects whether or not the spindle motor is stopped; and a control means that controls the stop of the spindle motor based on detection outputs of the level comparator and the window comparator. (2) The control means, for the spindle motor,
First, the reverse brake is applied, and when the detection output of the level comparator occurs when the detection output of the window comparator is not generated, the forward rotation brake is applied, and then, when the detection output of the window comparator occurs, the dynamic brake is applied for a predetermined period of time. 2. The spindle motor stop control device according to claim 1, wherein the spindle motor stop control device controls the spindle motor according to claim 1. (3) A stop control device for a spindle motor that rotationally drives an information recording disk, comprising a rotation speed detection means for generating a rotation speed signal having a level corresponding to the rotation speed of the spindle motor, and a signal level of the rotation speed signal. a window comparator for detecting that the rotation speed signal is within a range of upper and lower reference levels with the reference level corresponding to the zero rotation speed of the spindle motor as the center level; The spindle motor is characterized by comprising: a level comparator for detecting that the level has fallen below a reference level set low; and a control means for controlling the stop of the spindle motor based on the respective detections and outputs of the window comparator and the level comparator. Spindle motor stop control device. (4) The control means, for the spindle motor,
First, the reverse brake is applied, and when the detection output of the level comparator occurs when the detection output of the window comparator is not generated, the forward rotation brake is applied, and then, when the detection output of the window comparator occurs, the dynamic brake is applied for a predetermined period of time. 4. The spindle motor stop control device according to claim 3, wherein the spindle motor stop control device controls the spindle motor according to the invention.