JPH06243484A - Pickup driving device - Google Patents

Abstract

PURPOSE:To increase the pickup driving speed and also to reduce the power consumption by subtracting the number of tracks down to a target track stepwise and generating the continuous waveforms based on the sabtraction value obtained at each prescribed time. CONSTITUTION:The 3rd target number of tracks is supplied to an access command value generator means 23 from a target track setting means 22. The means 23 outputs the access command value 11 to a sample-and-hold circuit 30. The circuit 30 holds the value 32 obtained by deleting the high frequency area of the value 11 in a prescribed time tau. Then the circuit 30 converts the value 32 into the driving electric power via an amplifier 24, a position compensating circuit 25, and a drive amplifier 26 and outputs the electric power to a drive mechanism 27. A series of these actions are continuously carried out, and the value 32 is held in the time tau and then sent out every time a target track is set. Thus a pickup is finally moved up to a track P2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a pickup which outputs the drive power of the pickup on the basis of a continuous waveform generated by subtracting the number of tracks up to a target track stepwise and by a subtraction value at every predetermined time. Regarding

[0002]

2. Description of the Related Art A conventional example will be described with reference to the drawings. Figure 3
FIG. 4 is a schematic block diagram showing a conventional pickup driving device, FIG. 4 is a diagram for explaining a movement state of an objective lens (pickup) on a disc to a target track,
FIG. 5 is a diagram for explaining a signal output state of a conventional pickup driving device, and FIG. 5A is a diagram showing a target track setting timing of a target track setting means,
(B) is a diagram showing a command value generated by the access command value generating means. The drive device 1 of the pickup shown in FIG. 3 is roughly composed of a target track setting means 2, an access command value generating means 3, an amplifier 4, a phase compensation circuit 5, a drive amplifier 6, a drive mechanism 7, an address detector 8, and an adder / subtractor 9. It is configured.

The target track setting means 2 is adapted to set the movement amount of the pickup. That is,
A value (the number of tracks) of how many tracks the pickup moves from the current track is set for each predetermined time τ. The access command value generating means 3 outputs a preset access command value when the first track setting value is input from the target track setting means 2, and otherwise, the address detector 8 and the target. The access command value generated based on the signal from the track setting means 2 is output during the next predetermined time τ.

The amplifier 4 is adapted to amplify and output the access command value. The phase compensating circuit 5 outputs the access command value to the drive amplifier 6 so as to match the phase of the motor of the drive mechanism. The drive amplifier 6 outputs starting power to the drive mechanism 7 that drives the pickup based on the input access signal. The address detector 8 detects the position of the pickup from the number of tracks the pickup crosses and outputs it to the adder / subtractor 9.

Next, the operation of the pickup driving device having the above structure will be described with reference to FIGS. 4 and 5A and 5B. First, address information of a track to be moved to the target track setting means 2 (for example, information that moves to the position of "track P2" in FIG. 4) is input. After that, the target track setting means 2 sets the first target track number to be moved within a predetermined time τ from the current position of the track P1 (for example, N1 = shown in FIG. 4).
The setting value is output to the access command value generating means 3 at the timing shown in FIG. 5A.

The access command value generating means 3 to which the target number of tracks for the first time is inputted converts the command value inputted in advance into driving power through the amplifier 4, the phase compensation circuit 5 and the drive amplifier 6. Output to the drive mechanism 7. Then, the drive mechanism 7 moves the pickup by the target number of tracks for the first time within a predetermined time τ. At this time, the position (track) of the moving pickup is always detected by the address detector 8, and the adder / subtractor 8 calculates the difference from the first target track number. It is input to the generation means 3. From the subtraction result, the access command value generating means 3 always generates a sawtooth-shaped access command value 10 for a predetermined time τ as shown in FIG. 5B.

After that, the target number of tracks for the second time (for example, N2 = 1000 tracks shown in FIG. 4 is set).
Is inputted from the target track setting means 2 to the access command value generating means 3, and the access command value 10 is converted into drive power through the amplifier 4, the phase compensation circuit 5 and the drive amplifier 6 and output to the drive mechanism 7. . Then, similarly to the above, the access command value generating means 3 determines the predetermined value as shown in FIG. 5B based on the calculation result of the difference between the position (track) of the moving pickup and the second target track number. A sawtooth access command value 11 at time τ is generated.

A series of these operations are continuously performed to generate an access command value for each target track setting, and finally the pickup is moved to the track P2. Figure 6
FIG. 4 is a diagram showing the relationship between the number of moving tracks and the acceleration and speed of the pickup in the series of operations. The sawtooth waveform indicating the acceleration in the figure corresponds to the command value generated by the access command value generating means 3 described above.

[0009]

However, in recent years, it has been desired to shorten the search time for finding the beginning of music information recorded on a disc, and in order to cope with this, position detection control (access control) in the pickup is required. Performance (speed)
Improvement is desired. However, in order to improve the performance of the access control of the drive device for the pickup having the above-mentioned configuration, it is considered that the performance is improved if the predetermined time τ is shortened and the position is detected in more detail than the present time. If τ is shortened, the pickup must be moved with high periodicity (to give acceleration / deceleration acceleration in a short time). For this reason, there may be a case where it is necessary to supply a voltage equal to or higher than the specified value of the drive power supply for the pickup. However, the use of the high voltage power source causes the size of the power source to be large, and also causes the size and weight of the entire driving device to increase.

Further, when the same power supply as that of the conventional one is used, even if a control signal (access command value) higher than the power supply voltage is input, the output is actually higher than the set voltage (upper and lower limit values of the power supply voltage). Is not supplied (saturated), the desired acceleration cannot be obtained. As a result, the pickup moves slower than the desired movement, and the performance cannot be improved. Further, in the drive device as described above, since a method of generating a command value that forms a sawtooth waveform as described above as a method of controlling acceleration (driving power), there is a deceleration period in which acceleration may not be generated. However, as in the above, output a certain number of target tracks and actually move the pickup in response to that,
Acceleration and deceleration are repeated to create a state where the acceleration is 0 (see FIG. 7). As a result, wasteful power is consumed.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a pickup driving device in which the performance of position detection control (access control) in the pickup is improved and the power consumption is low. .

[0012]

A pickup driving apparatus according to the present invention includes means for stepwise subtracting the number of tracks up to a target track, and means for generating a continuous waveform based on a subtraction value at every predetermined time. Means for outputting the drive power of the pickup based on the waveform component in the low frequency region of the continuous waveform.

[0013]

In the above means, a signal output close to a rectangular wave is obtained by using a method such as sample hold based on the low frequency component of the continuous waveform, and the difference between the upper and lower limits of acceleration is not large like a sawtooth wave. Since the constant drive power is output for a predetermined time, the drive operation of the pickup can be accelerated. In addition, power consumption can be suppressed low.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing a pickup driving device according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining an output state of an access command value. The drive device 21 of the pickup shown in FIG.
Access command value generation means 23, sample hold circuit 3
0, amplifier 24, phase compensation circuit 25, drive amplifier 2
6, drive mechanism 27, address detector 28, adder / subtractor 29
It is composed of

The target track setting means 22 sets the amount of movement of the pickup as described above. That is, a value (the number of tracks) of how many tracks the pickup moves from the current track is set for each predetermined time τ. The access command value generating means 23 outputs a preset access command value when the first track setting value from the target track setting means 22 is input, and in other cases, the address detector 28 and the above-mentioned Target track signal setting means 22
Based on the signal from, the access command value for moving to the next predetermined time τ is output.

The sample and hold circuit 30 generates a value from the waveform component in the low frequency region, which is obtained by removing the waveform component in the high frequency region from the continuous waveform from the access command value generating means 23 (for example, shown in FIG. 5B). A value obtained by averaging the sawtooth waveform) is sampled, and the value is held and output for a predetermined time τ. This sample operation is performed by inputting the target track setting signal input from the target track setting means 22, for example. It should be noted that the sample hold circuit 30 is preferably set not to output the deceleration command value during the acceleration period but to output “0” instead. The amplifier 24 amplifies and outputs this access command value.

The phase compensation circuit 25 outputs the access command value to the drive amplifier 26 so as to match the phase of the motor of the drive mechanism. The drive amplifier 26 supplies starting power to the drive mechanism 2 based on the input access signal.
Output to 7. The address detector 28 detects the position of the pickup from the number of tracks the pickup crosses and outputs it to the adder / subtractor 29.

Next, the operation of the pickup driving device having the above construction will be described with reference to FIGS. 2 and 4 and 6. First, the address information (for example, information for moving to the position of “track P2” in FIG. 4) of the finally moving track is input to the target track setting means 22.
After that, the target track setting means 22 sets the first target track number that moves from the current position of the track P1 for a predetermined time τ (for example, N1 = 10 shown in FIG. 4).
The setting value is output to the access command value generating means 23 at the timing shown in FIG. 2A.

The access command value generating means 23, to which the first target track number has been inputted, gives the command value inputted in advance to the sample hold circuit 30. Then, the sample hold circuit 30 samples this value, holds it for a predetermined time τ and outputs it to the amplifier 24, and the amplifier 24, the phase compensation circuit 25, and the drive amplifier 26.
It is converted to drive power via and output to the drive mechanism 27.
The command value input in advance in the present embodiment is a value generated from the waveform component in the low frequency region obtained by removing the waveform component in the high frequency region of the continuous waveform (sawtooth waveform) of acceleration shown in FIG. 6 (for example, FIG. 6). The value LO) obtained by averaging the sawtooth waveform shown in FIG. Then, the drive mechanism 27 moves the pickup by the first target track number in a predetermined time τ.

At this time, the position (track) of the moving pickup is always detected by the address detector 28, the difference from the first target track number is calculated by the adder / subtractor 29, and the access command value generating means is generated. 23 is input. The access command value generating means 23 generates the access command value 10 at the predetermined time τ as shown in FIG. 2B based on the calculation result.

After that, the second target track number (for example, N2 = 1000 tracks shown in FIG. 4 is set).
Is inputted from the target track setting means 22 to the access command value generating means 23, the access command value 10 is outputted to the sample hold circuit 30. At the same time, a sample hold signal is input from the target track setting means 22 to the sample hold circuit 30, and the sample hold circuit 30 removes the high frequency region of the access command value 10 (for example, the waveform of the access command value 10). (Averaged value) 31 (see FIG. 2C) is sampled and held for a predetermined time τ, and the amplifier 24,
It is converted into drive power through the phase compensation circuit 25 and the drive amplifier 26 and output to the drive mechanism 27. Then, similarly to the above, the access command value generating means 23 determines the predetermined value as shown in FIG. 2B based on the calculation result of the difference between the position (track) of the moving pickup and the second target track number. An access command value 11 at time τ is generated.

Then, the access command value generating means 23
The third target track number is input from the target track setting means 22 and the access command value generating means 23 outputs the access command value 11 to the sample hold circuit 30. At the same time, a sample and hold signal is input from the target track setting means 22 to the sample and hold circuit 30, and the sample and hold circuit 30 removes the high frequency region 32 of the access command value 11 (see FIG. 2C). It is held for a predetermined time τ and converted into drive power through the amplifier 24, the phase compensation circuit 25, and the drive amplifier 26 and output to the drive mechanism 27. These series of operations are continuously performed, and a value obtained by removing the high frequency region of the access command value is held and output for a predetermined time τ for each target track setting, and finally the pickup is moved to the track P2.
Move to.

As described above, according to the above embodiment, a value based on the low frequency component obtained by removing the waveform component in the high frequency region of the continuous waveform such as a sawtooth wave is subjected to, for example, sample hold, and then a rectangular wave. A signal output close to is obtained. For this reason, the difference between the upper and lower limits of the acceleration is not large like a sawtooth wave, and the execution acceleration can be almost doubled. Since a constant drive power can be output for a predetermined time, the drive operation of the pickup can be accelerated. In addition, power consumption can be suppressed low.

The present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, a low-pass filter may be used instead of the sample hold circuit as means for removing the waveform component in the high frequency region of the access command value.

[0025]

As described above, according to the present invention, it is possible to provide a pickup driving device in which the performance of the position detection control (access control) in the pickup is improved and the power consumption is low.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing a drive device for a pickup according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a signal output state of a pickup driving device according to an embodiment of the present invention,
(A) is a diagram showing the target track setting timing of the target track setting means, (b) is a diagram showing the command value generated by the access command value generating means, and (c) is generated by the sample hold circuit. It is a diagram showing an output signal.

FIG. 3 is a schematic block diagram showing a conventional pickup driving device.

FIG. 4 is a diagram for explaining a movement state of an objective lens (pickup) on a disc to a target track.

FIG. 5 is a diagram for explaining a signal output state of a conventional pickup driving device, FIG. 5A is a diagram showing a target track setting timing of a target track setting means,
(B) is a diagram showing a command value generated by the access command value generating means.

FIG. 6 is a diagram showing the relationship between the number of moving tracks and the acceleration and speed of the pickup in a series of operations of a conventional pickup driving device.

FIG. 7 is a diagram for explaining a signal waveform in a state where acceleration is not generated in the conventional example.

[Explanation of symbols]

 21 pickup drive device 22 target track setting means 23 access command value generating means 24 amplifier 25 phase compensation circuit 26 drive amplifier 27 drive mechanism 28 address detector 29 adder / subtractor 30 sample hold circuit

Claims (1)

[Claims] 1. A means for continuously subtracting the number of tracks up to a target track to generate a continuous waveform on the basis of a subtraction value at every predetermined time, and based on a waveform component in a low frequency region of the continuous waveform. A drive device for a pickup, comprising: means for outputting drive power for the pickup.