JPH10334581A - Motor drive control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a rush current at the time when disturbance is applied to a motor having a small DC resistance value. SOLUTION: An AND gate 15 is interposed between a current buffer 12b and the preceding stage of a three-phase motor drive circuit 12d forming a course of supplying a PWM(pulse width modulation) error signal Ser from a servo signal generating circuit 13g for CLV to the motor 11, and also a PWM mask signal Sms is supplied from a PWM signal generating circuit 41p in a microcomputer 41 to this AND gate 15 to be opened and closed, so that a loop gain of a CLV servo is reduced. Repeating frequencies of the error signal and the mask signal are set to about 88 kHz and about 880 kHz respectively, and the pulse width of the mask signal is modulated to be narrow or wide in accordance with a high or low noncontrol voltage of a battery 44 for a power source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive control device suitable for use in, for example, a spindle motor drive control device of a disk recording / reproducing apparatus.

[0002]

2. Description of the Related Art Recently, a portable audio recording / reproducing apparatus (disk recording / reproducing apparatus) using a small-sized magneto-optical disk (mini-disc, MD) as a recording medium has been proposed by the present applicant and is now commercially available. Reached. This disc recording and playback device combines the advantages of a compact cassette, such as "compact" and "recordable," with the advantages of a compact disc (CD), such as "high sound quality" and "quick random access." Is expected as a next-generation personal audio to replace

In this type of portable disk recording / reproducing apparatus, a direct current brushless type spindle motor is used to drive a mini disk. For controlling the spindle motor, a pulse width modulation (PWM) driving method is widely used.

As shown in FIG. 5, in a drive control system 10 for a conventional spindle motor, a direction signal Sd from a servo signal generation circuit 13g is directly supplied to a three-phase motor drive circuit 12d and a servo signal generation circuit The error signal Ser from the circuit 13g is supplied to the three-phase motor drive circuit 12d through the current buffer 12b.
Supplies a drive current to the spindle motor 11. In addition, DC power is supplied to the current buffer 12b from a battery 44 for power supply.

The above-mentioned error signal Ser is a signal of the PWM type as shown in FIG. 6, and its repetition frequency is, for example, about 88 kHz, and therefore, the repetition cycle Te
Is set to about 11 mS, for example.

When the pulse occupancy (duty factor) of the error signal Ser changes in the range of 0 to 100%, a drive current proportional to the pulse occupancy is supplied to the spindle motor 11, Desired CLV control is realized with respect to the rotation of the mini disc 1.

[0007]

By the way, miniaturized recording / reproducing apparatuses are always required to be reduced in size and voltage. In response to this demand, for example, two AA alkaline batteries are used. Something that works is commercially available. Also, in response to such a reduction in the voltage, the DC resistance value of the spindle motor tends to decrease.

However, in the conventional spindle motor drive control system 10, since the loop gain of the CLV servo is set high, if a motor having a small DC resistance is used, a large rush occurs when a disturbance is applied to the spindle motor. There is a problem that current flows.

In the conventional drive control system 10, the MD
Due to the configuration of the system IC, there is little freedom in setting the loop gain of the CLV servo, and it has been difficult to independently control only the loop gain.

In view of the above, an object of the present invention is to provide a CL
I can finely control the loop gain of V servo,
It is an object of the present invention to provide a motor drive control device that can reduce a rush current that flows when a disturbance is applied to a motor having a small DC resistance value.

[0011]

In order to solve the above-mentioned problems, a motor drive control device according to the present invention is arranged such that a pulse width modulation signal output from a speed servo signal generation circuit is supplied to a motor via a motor drive circuit. In the motor drive control device, a gate means is interposed between the speed servo signal generation circuit and the motor drive circuit, and a second pulse width modulation signal for opening and closing the gate means is generated. An open / close signal generation circuit is provided.
The repetition period of the pulse width modulation signal is set shorter than the repetition period of the pulse width modulation signal output from the servo signal generation circuit.

In the motor drive control device having the above-described structure, the first pulse width modulation signal is gated by the second pulse width modulation signal, so that the loop gain of the motor servo system is controlled by the second pulse width modulation signal. Controlled.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a motor drive control device according to the present invention will be described with reference to FIGS. This embodiment is a case where the present invention is applied to a drive control device of a spindle motor of the portable mini-disc recording / reproducing apparatus described above.

First, a mini disc recording / reproducing apparatus will be described with reference to FIG. The mini disc recording / reproducing apparatus is compatible with a read-only optical disc in which audio data is recorded in the form of physical pits, similarly to a CD.

[Structure of Disk] In FIG. 4, for the optical disk 1, for example, a rewritable magneto-optical disk having a magneto-optical recording film and capable of recording, reproducing, and erasing is used.
The outer diameter of the disk 1 is, for example, 64 mm.
The recording tracks are formed spirally at a pitch of, for example, 1.6 μm. The disk 1 has a constant linear velocity,
For example, it is rotated at 1.2 to 1.4 m / s. Then, the audio information is converted into a digital signal on the disc 1,
In addition, by being compressed and recorded, the target information can be recorded and reproduced for 130 Mbytes or more.

A pre-groove for tracking control is formed on the disk 1 in advance. In this case, in particular, in this example, the pre-groove is superimposed on a wobbling signal for tracking and an address ( Absolute address) code is recorded.

On the disc 1, information on recorded audio data is recorded at the innermost track position. This is generally the TOC (Tabl
e ofcontent), and includes the number of recorded songs, information on the recording position of each song, the performance time of each song, and the like.

The disk 1 is housed in a disk cartridge 2 for dust prevention and damage prevention.

[Recording System of Recording / Reproducing Apparatus] The recording / reproducing apparatus shown in FIG. 4 is designed to be as simple as possible by using an IC. First, the time of recording on the magneto-optical disk 1 will be described.

2 through a pair of input terminals 21L and 21R.
The analog audio signal of the channel is sampled at a sampling frequency of 44.1 kHz in the AD converter 22, and each sampled value is converted into a 16-bit digital signal. This 16-bit digital signal is converted to a highly efficient coding system ATRAC (Adaptive TRansfo
rm Acoustic Coding), and in this case, the input digital data is compressed to, for example, about 1/5. As a method of this data compression, for example, ADPCM with a quantization number of 4 bits
(Adaptive DeltaPulse Code Modulation) is used.

For example, it is better to divide the input digital data into a plurality of bands so that the higher the band, the wider the bandwidth, and to provide a plurality of samples for each of the divided bands (the number of samples should be the same in each band). Good), a method of performing orthogonal transformation for each block of each band to obtain coefficient data, and performing bit allocation for each block based on the coefficient data can also be used.
In this case, the data compression method takes into account the human auditory perception characteristics of sound and can perform data compression with high efficiency.

In this way, the digital data DA from the A / D converter 22 is processed by the processing in the compression circuit 23R to about 1
/ 5, and the compressed data d
a is transferred to the buffer memory 25 controlled by the memory control circuit 24. In this example, a D-RAM having a capacity of 1 Mbit is used as the buffer memory 25.

The memory control circuit 24 transmits the compressed data da from the buffer memory 25 at a transfer speed approximately five times as fast as the writing speed unless a track jump in which the recording position on the disk 1 jumps due to vibration or the like during recording. The data is sequentially read, and the read data is
Transfer to R.

When it is detected that a track jump has occurred during recording, the data transfer to the encoding circuit 26R is stopped, and the compressed data da from the processing circuit 23R is stopped.
Is stored in the buffer memory 25. Then, when the recording position is corrected, control is performed to restart the data transfer from the buffer memory 25 to the encoding circuit 26R.

The detection of whether or not a track jump has occurred can be performed, for example, by providing a vibrometer in the apparatus and detecting whether or not the magnitude of the vibration is such that a track jump occurs. Also, as described above, when forming a pre-groove on the disc 1 of this example,
An address code is recorded so as to be superimposed on a wobbling signal for tracking control. Therefore, it is possible to read the address code from the pre-groove at the time of recording and detect a track jump from the decoded output. Alternatively, a track jump may be detected by taking the OR of the vibrometer and the address code. When a track jump occurs, the power of the laser beam for magneto-optical recording is reduced or the power is set to zero.

The correction of the recording position when a track jump occurs can be performed using the address code. Further, as can be understood from the above description, the data capacity of the buffer memory 25 in this case can store the compressed data da corresponding to the time from the occurrence of the track jump to the correct correction of the recording position. Minimum capacity is required. In this example, the capacity of the buffer memory 25 has 1M bits as described above, and this capacity is selected as having a sufficient margin to sufficiently satisfy the above-mentioned conditions.

In this case, the memory control circuit 24
During recording, during normal operation, memory control is performed so that data stored in the buffer memory 25 is reduced as much as possible. For example, when the data amount of the buffer memory 25 becomes equal to or more than a predetermined amount, a predetermined amount of data, for example, 32 sectors (one sector corresponds to one CD-ROM)
Only data of a sector (about 2 Kbytes) is read from the buffer memory 25 and memory control is performed so that a write space of a predetermined data amount or more is always secured.

The data encoding circuit 26R converts the compressed data da transferred from the buffer memory 25 into a CD-
Encode to ROM sector structure data. In addition,
Data including audio data for 32 sectors is hereinafter referred to as a cluster.

The output data (data in cluster units) of the data encoding circuit 26R is supplied to a recording encoding circuit 27. In this recording encoding circuit 27,
Performs encoding processing for error detection and correction on data,
A modulation process suitable for recording, such as an EFM encoding process in this example, is performed. The code for error detection and correction is CD in this example.
The interleave is changed for CIRC (Cross Interleave Reed-Solomon Code). Since the recording data is intermittent data in cluster units, a plurality of cluster connection sectors are added before and after a 32 sector cluster.

The encoded data from the recording encoding circuit 27 is supplied to a magnetic head 29 via a magnetic head driving circuit 28. The magnetic head drive circuit 28 drives the magnetic head 29 so as to apply a modulation magnetic field according to the recording data to the disk 1 (magneto-optical disk). The audio data supplied to the head 29 is in cluster units, and recording is performed intermittently.

The disk 1 is stored in the cartridge 2. When the disk 1 is loaded in the apparatus, the shutter plate is opened, and the disk 1 is exposed from the shutter opening. The rotating shaft of the spindle motor 11 for driving the disk is inserted and connected to the opening for inserting the spindle.
Is driven to rotate. In this case, the spindle motor 11
The rotation speed of the disk 1 is controlled by the servo control circuit 13 through the drive circuit 12 so as to rotate the disk 1 at a linear velocity of 1.2 to 1.4 m / s.

The magnetic head 29 faces the disk 1 exposed from the shutter opening of the cartridge 2.
An optical head 31 is provided at a position facing the surface of the disk 1 opposite to the surface facing the magnetic head. The optical head 31 includes, for example, a laser light source such as a laser diode, a collimator lens, an objective lens, an optical component such as a polarizing beam splitter, a cylindrical lens, and a photodetector. A laser beam having a constant power larger than that at the time of reproduction is irradiated. By this light irradiation and the modulated magnetic field by the magnetic head 29, data is recorded on the disk 1 by thermomagnetic recording. The magnetic head 29 and the optical head 31 are both configured to be able to move in the radial direction of the disk 1 by a feed motor 31m controlled by the servo control circuit 13.

At the time of this recording, the optical head 3
1 is supplied to the address decoding circuit 34 via the RF signal processing circuit 32, and the address code from the pre-groove of the disk 1 is extracted and decoded. Then, the decoded address information is supplied to the recording encoding circuit 27, inserted into the recording data as address information, and recorded on the disk. The address information from the address decode circuit 34 is also supplied to the system control circuit 41, and is used for recognition of the recording position and position control as described above.

A signal from the RF signal processing circuit 32 is supplied to the servo control circuit 13, and a control signal for constant linear velocity servo is formed from a signal from the pre-groove of the disk 1, and the spindle motor 11 Controlled.

The mode of each circuit is switched between the recording mode and the reproducing mode by a mode switching signal R / P from the system control circuit 41. The system control circuit 41 includes a plurality of operation keys 4 for recording and playback.
The operation mode is designated by operating the key 42. The system control circuit 41 includes:
A liquid crystal display 43 for displaying an operation mode or the like is connected.

[Reproducing System of Recording / Reproducing Apparatus] The disc 1 loaded in the apparatus is driven to rotate by a spindle motor 11. Then, in the same manner as during recording, the spindle motor 11 drives the disk 1 at the same speed as during recording, that is, a linear speed of 1.2 to 1.4 m / sec, based on a signal from the pregroove by the servo control circuit 13. At s, the rotation speed is controlled to be constant.

At the time of reproduction, the optical head 31 detects a focus error by, for example, an astigmatism method by detecting reflected light of a laser beam applied to a target track, and detects a tracking error by, for example, a push-pull method. At the same time, a difference in the polarization angle (Kerr rotation angle) of the reflected light from the target track is detected, and a reproduced RF signal is output.

The output of the optical head 31 is supplied to an RF signal processing circuit 32. The RF signal processing circuit 32 extracts a focus error signal and a tracking error signal from the output of the optical head 31 and supplies them to the servo control circuit 13, and also converts the reproduced signal into a binary signal and supplies it to the reproduction decoding circuit 33.

The servo control circuit 13 controls the focus of the optical system of the optical head 31 so that the focus error signal becomes zero, and controls the optical system of the optical head 31 so that the tracking error signal becomes zero. Perform tracking control.

The RF signal processing circuit 32 extracts an address code from the pregroove and supplies it to the address decode circuit 34. The address information from the decode circuit 34 is supplied to the system control circuit 41, and is used by the servo control circuit 13 for controlling the reproduction position of the optical head 31 in the disk radial direction. Further, the system control circuit 41 can also use the address information in sector units extracted from the reproduction data to manage the position on the recording track where the optical head 31 is scanning.

At the time of this reproduction, as will be described later,
The compressed data read from the disk 1 is written to the buffer memory 25 and read and decompressed.
Is read from the buffer memory 25, for example.
Is performed intermittently so that the data stored in the storage device does not fall below a predetermined amount.

The data read from the disk 1 is R
The signal is supplied to the reproduction decoding circuit 33 via the F signal processing circuit 32. The reproduction decoding circuit 33 receives the binarized reproduction signal from the RF signal processing circuit 32 and performs processing corresponding to the recording encoding circuit 27, that is, EFM decoding processing, decoding processing for error detection and correction, and interpolation processing. And so on. The output data of the reproduction decoding circuit 33 is supplied to the data decoding circuit 26P.

The data decoding circuit 26P is provided with a CD-
The data in the ROM sector structure is decoded into compressed original data.

The output data of the data decoding circuit 26P is transferred to a buffer memory 25 controlled by a track jump memory control circuit 24, and is written at a predetermined writing speed.

At the time of this reproduction, the memory control circuit 24 writes the compressed data from the data decoding circuit 26P unless a track jump occurs in which the reproduction position jumps due to vibration or the like during the reproduction. The data is sequentially read at a transfer rate of about 1/5 times the transfer rate, and the read data is transferred to the data expansion processing circuit 23P based on the ATRAC method. In this case, the memory control circuit 2
Reference numeral 4 controls writing / reading of the buffer memory 25 so that the amount of data stored in the buffer memory 25 does not fall below a predetermined value.

When it is detected that a track jump has occurred during reproduction, writing of data from the data decoding circuit 26P to the buffer memory 25 is stopped, and only data transfer to the data decompression processing circuit 23P is performed. .
Then, when the reproduction position is corrected, control is performed so that data writing from the data decoding circuit 26P to the buffer memory 25 is restarted.

As in the case of recording, whether or not a track jump has occurred is detected, for example, by using a vibrometer, by using the decoded output of the address decode circuit 34, or by taking the OR of the vibrometer and the address code. A method of detecting a track jump can be used. Further, at the time of this reproduction, as described above, the address information and the address information in sector units are extracted from the reproduced data, and thus can be used.

As will be understood from the above, the data capacity of the buffer memory 25 at the time of this reproduction is data corresponding to the time from the occurrence of a track jump to the correct correction of the reproduction position. The minimum capacity that can always be stored is required. This is because if there is enough capacity, even if a track jump occurs, the buffer memory
This is because data can be continuously transferred to the data decompression circuit 23P. The 1M bits as the capacity of the buffer memory 25 in this example is selected as a sufficient capacity so as to sufficiently satisfy the above-described conditions.

As described above, the memory control circuit 2
4 performs memory control such that predetermined data more than necessary minimum is accumulated in the buffer memory 25 as much as possible during normal operation. In this case, for example, when the data amount of the buffer memory 25 becomes equal to or less than a predetermined amount, the optical head 31 intermittently takes in data from the disk 1 and writes data from the data decode circuit 26P. Then, memory control is performed so that a read space equal to or larger than a predetermined data amount is always secured.

In the data decompression processing circuit 23P, the ADPC
The M data is expanded about 5 times, contrary to the data compression processing at the time of recording. The expanded digital audio data is
The signal is supplied to the DA converter 35 through the memory control circuit 24, converted into a two-channel analog audio signal, and output from the output terminals 36L and 36R.

[Power Supply System] As the battery 44 for the power supply of the mini disk recording / reproducing apparatus as described above, usually, a secondary battery such as a lithium ion storage battery, a nickel hydrogen (Ni-MH) storage battery, or an alkaline dry battery is used. The DC power from such a battery 44 is supplied directly to each unit of the device, and is also converted to a predetermined voltage by a DC-DC converter 45 and supplied to each unit of the device. In addition, a so-called AC adapter can be connected to an external power supply terminal 46 commonly connected to the battery 44 and the DC-DC converter 45.

FIG. 1 shows the configuration of an embodiment of the motor drive control device of the present invention. In FIG. 1, portions corresponding to FIGS. 4 and 5 described above are denoted by the same reference numerals, and a description thereof is partially omitted.

In FIG. 1, in the drive control system 10A of the spindle motor, an AND gate 15 is interposed between the servo signal generating circuit 13g and the current buffer 12b, and a PWM signal generating circuit 41p is provided in the microcomputer 41. Can be

The direction signal Sd from the servo signal generation circuit 13g is directly supplied to the three-phase motor drive circuit 12d,
The error signal Ser from the servo signal generation circuit 13g is supplied to one input terminal of the AND gate 15, and
The mask signal Sms from the PWM signal generation circuit 41p in the microcomputer 41 is supplied to the other input terminal of the AND gate 15. The output of the AND gate 15 is supplied to the three-phase motor drive circuit 12d through the current buffer 12b, and the drive current is supplied to the spindle motor 11 from the drive circuit 12d.

The current buffer 12b is supplied with DC power from a battery 44 for power supply, and
4 is supplied to the PWM signal generation circuit 41p as a modulation signal. Note that an external power supply terminal 46 is connected to the battery 44.

Then, as shown in FIG. 2, for example, a single transistor 15Q having a common emitter connection can be used in place of the AND gate 15 as described above.

That is, in FIG. 2, in the drive control system 10B of the spindle motor, a resistor 16 is interposed between the servo signal generating circuit 13g and the current buffer 12b, and the emitter 16 is connected to the buffer 12b side of the resistor 16 The collector of the connected transistor 15Q is connected, and a PWM signal generation circuit 41p is provided in the microcomputer 41.

The direction signal Sd from the servo signal generation circuit 13g is directly supplied to the three-phase motor drive circuit 12d,
The error signal Ser from the servo signal generation circuit 13g is supplied to the current buffer 12b through the resistor 16, and the base of the transistor 15Q is supplied with the mask signal Sms from the PWM signal generation circuit 41p in the microcomputer 41. You. The output of the current buffer 12b is supplied to a three-phase motor drive circuit 12d.
A drive current is supplied to the spindle motor 11 from 2d.

The current buffer 12b is supplied with DC power from a battery 44 for power supply, and
4 is supplied to the PWM signal generation circuit 41p as a modulation signal. An external power supply terminal 46 is connected to the battery 44.

In the configuration of the drive control system 10B for the spindle motor as described above, the cost is reduced.

[Driving Current Control] Next, the driving current control according to the embodiment of the present invention will be described with reference to FIG.

In the embodiment of FIG. 1, as shown in FIG. 3A, the pulse width changes with the repetition period Te narrowly and broadly.
The error signal Ser in the WM format is transmitted to the servo signal generation circuit 13.
Is supplied to one input terminal of the AND gate 15.
Also, according to the level of the terminal voltage of the battery 44 as shown in FIG. 3B, the PWM signal generation circuit 41p in the microcomputer 41 outputs a pulse with a repetition period Tm and a narrow and wide pulse width as shown in FIG. 3C. The changing mask signal Sms is supplied, and the AND gate 15 is opened and closed by the mask signal Sms.

The output of the AND gate 15 is shown in FIG.
As shown in D, the error signal Ser of FIG. 3A is keyed by the mask signal Sms of FIG. 3C, and the average value is almost proportional to the pulse occupancy of the mask signal Sms. Therefore, the gain of the CLV speed servo of the spindle motor can be changed according to the duty ratio of the mask signal Sms.

In this embodiment, the repetition frequency of the error signal Ser is set to, for example, about 88 kHz, and the repetition cycle Te is set to, for example, about 11 mS. The repetition frequency of the mask signal Sms is, for example, about 8
80 kHz, and therefore the repetition period Tm is set, for example, to about 1.1 mS.

The pulse occupancy of the mask signal Sms is minimized for an overvoltage of 150% of the rated voltage of the battery, for example, assuming that an AC adapter is connected to the external power supply terminal 46. The voltage is set in a desired range so as to be maximum with respect to the working voltage.

Thus, in this embodiment, CLV
The servo loop gain can be finely controlled, and the rush current can be significantly reduced even when disturbance is applied to the spindle motor having a small DC resistance value.

Further, the operable time when using the battery can be extended by reducing the rush current.

In the embodiment of FIG. 2, by inverting the polarity of the mask signal Sms shown in FIG. 3C, the same drive current control as described above is performed, and the same effect is obtained.

[0069]

As described above, according to the present invention, a rush current that flows when a disturbance is applied to a motor having a small DC resistance value can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a motor drive control device according to the present invention.

FIG. 2 is a block diagram showing a configuration of another embodiment of the present invention.

FIG. 3 is a time chart for explaining drive current control according to the embodiment of the present invention.

FIG. 4 is a block diagram for explaining the present invention.

FIG. 5 is a block diagram illustrating a configuration example of a conventional motor drive control device.

FIG. 6 is a time chart for explaining the operation of the conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mini disk, 10A, 10B ... Drive control system, 11
... Spindle motor, 12b ... Current buffer, 12d ...
3 phase motor drive circuit, 13g ... servo signal generation circuit, 1
5 AND gate, 15Q transistor 41 41 microcomputer 41p PWM signal generation circuit 44
... Battery, Sd ... Direction signal, Ser ... Error signal, Sms
… Mask signal

Claims (2)

[Claims] 1. A motor drive control device in which a pulse width modulation signal output from a speed servo signal generation circuit is supplied to a motor via a motor drive circuit, wherein the speed servo signal generation circuit and the motor drive circuit are provided. An opening / closing signal generating circuit for generating a second pulse width modulation signal for opening and closing the gate means, and providing a servo control circuit for controlling the repetition period of the second pulse width modulation signal A drive control device for a motor, wherein the drive period is set shorter than a repetition period of a pulse width modulation signal output from a signal generation circuit. 2. An uncontrolled power supply voltage is supplied to the switching signal generation circuit as a modulation signal, and the pulse width of the second pulse width modulation signal is modulated to be narrow and wide according to the level of the power supply voltage. The motor drive control device according to claim 1, wherein: