JP2003051115A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser driving integrated circuit allowing the reduction of cost while having the simple circuit constitution and the small circuit scale as to the laser driving integrated circuit for controlling a pulse-divided laser driving waveform, in a recordable optical disk device. SOLUTION: A laser driving integrated circuit 11 is constituted of a mark/ space length detection means 4 for detecting the mark length and the space length, an address generating means 5 for changing over an address signal, a driving waveform storage means 6 for outputting the selected driving waveform information, a FIFO storage means 7 for fetching the output information of the driving waveform storage means 6, a delay clock generating/selecting means 8 for selecting the delay clock, a current setting/changing over means 9 for selecting one channel among a plurality of channels, a driving means 10 for current-driving a laser diode 12, a clock generating means 3 for outputting various kinds of clock signals, and a write control means 2 for writing data supplied from a controller 1 into the driving waveform information storage means 6 and the current setting/changing over means 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser drive integrated circuit for controlling a pulse-divided laser drive waveform of a recordable optical disk device, and more specifically, it is possible to control the time timing of the drive waveform with high accuracy. The present invention relates to a laser drive integrated circuit corresponding to various drive waveforms and an optical disk control device equipped with the same.

[0002]

2. Description of the Related Art Conventionally, the basic principle of an optical disc is that a laser is irradiated when data corresponding to information "1" is recorded and a laser is recorded when data corresponding to information "0" is recorded. A general method is to perform only on / off control without irradiating. In recent years, there has been a demand for higher density optical disc recording / reproducing systems. With the increasing density of optical discs, the laser drive waveform can be changed according to the recording / reproducing characteristics of the disc and the recording material of the disc, and the time timing and current level It is required for the optical disc device to increase the reliability of the recorded data by adaptively changing the recording mark and controlling the recording mark shape. Therefore, when the recording mark shape is controlled, the drive waveform is controlled by a technique called a write strategy, in which the recording laser output is pulse-divided into multiple levels. As a conventional example of drive waveform control by this write strategy, Japanese Patent Application Laid-Open No. 11-283249 discloses a recordable optical disc device, particularly a laser drive integrated circuit for controlling multilevel laser drive waveforms and pulse-divided laser drive waveforms. In this regard, a laser drive integrated circuit corresponding to various drive waveforms capable of high-accuracy and high-speed switching and an optical disk device equipped with the same are disclosed. According to this, in the laser driving integrated circuit having the current setting / switching means for sequentially switching the current to be supplied to the laser diode to the set plurality of levels, the laser diode corresponds to the binary recording signal to be recorded on the recording medium. Drive waveform information storage means for storing one or more pieces of drive waveform information for driving
Drive waveform restoration means for restoring the drive waveform based on the storage information of the drive waveform information storage means and controlling the switching means,
Address generating means for generating an address signal for selecting drive waveform information of the first drive waveform information storage means on the basis of a binary recording signal to be recorded on a recording medium, drive waveform information supplied from the outside The control means for storing in the drive waveform information storage means No. 1 is provided.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In Japanese Patent No. 3249, the laser driving waveform of the mark length of the binarized recording signal NRZI is changed according to the adjacent space length to reduce the mark edge jitter on the recording medium. In the mark part, the laser power is increased and driven by multi-pulses, and in the space part, the laser diode is driven by the power for erasing the marks and spaces already recorded on the medium (power smaller than mark recording). When the mark is recorded, the length of the adjacent space is thermally affected on the medium, and the edge of the mark changes variously. In order to avoid this, the time timing of the recording waveform of the mark portion is changed in consideration of the adjacent space length. The mark length and the space length have nine discrete values from 3T to 11T (T is the minimum unit time of change of the binarized recording signal NRZI, and corresponds to the cycle of the clock CLK (f / 2)). It is encoded to take. If the adjacent space length is 6T or more, the thermal effect is the same, so the adjacent space length is 3
The drive waveform is controlled in consideration of four types of T, 4T, 5T and 6T or more. In the above conventional example, the address generating means includes mark / space length detecting means, and the mark / space length detecting means stores, in the first storage means, three values of the mark length and two adjacent space lengths as address information. The drive waveform information stored in the second drive waveform information storage means is selected based on the address information read from the first storage means by selecting the stored address information of the second drive waveform information storage means. Is selected, and the drive waveform restoring means restores the drive waveform based on the drive waveform information. However, the circuit configuration of the address generation means, the drive waveform restoration means, etc. relating to the drive waveform control disclosed in the above invention is complicated, the circuit scale is large, and the cost of the integrated circuit increases when integrated. There was a problem.
In view of the above problems, the present invention is a laser drive integrated circuit that controls a pulse-divided laser drive waveform in a recordable optical disc device, and can be realized at a low cost with a simple circuit configuration. A laser driving integrated circuit is provided.

[0004]

In order to solve the above problems, the present invention provides a laser drive integrated circuit for sequentially switching a current supplied to a laser diode among a plurality of set levels. In the optical disc device, the drive waveform information for driving the laser diode corresponding to the binary recording signal to be recorded on the recording medium is at least 1
Drive waveform information storage means for storing one or more pieces, first-in first-out storage means for taking in the stored information of the drive waveform information storage means in synchronization with a clock signal, and taking out in the order of the taken-in information, and storage of the first-in first-out storage means Current setting / switching means for controlling switching of current level based on information, and address signal for selecting drive waveform information of the drive waveform information storage means based on a binary recording signal to be recorded on a recording medium. Is provided, and write control means for storing drive waveform information supplied from the outside in the drive waveform information storage means. According to the present invention, a driving waveform to be recorded on an optical disk according to recording data is previously received from a controller and stored, a mark and a space length are detected from an NRZI signal which is recording data, and an optimum driving waveform is determined from the length. Generate an address for selection. The drive waveform selected by the address generation means is temporarily stored in a FIFO (first-in first-out storage means) and LD is generated at a clock synchronized with the storage timing of the optical disk.
A recording current is applied to. At this time, since the current is divided into three levels and flows, the current setting is switched according to the recording data. According to this invention, since these main circuits are relatively simplified and configured, the cost of the integrated circuit can be reduced when integrated.

According to a second aspect of the present invention, the address generating means is based on the mark length of the binarized recording signal, the preceding space length and the mark length and the succeeding space length, respectively, and the drive waveform information. Generating an address signal for selecting the drive waveform information of the storage means is also an effective means of the present invention. In the conventional write strategy method,
When a mark is recorded, the length of the adjacent space is thermally influenced on the medium, and the edge of the mark changes variously. In order to avoid this, the time timing of the recording waveform of the mark portion is changed in consideration of the adjacent space length.
Therefore, the circuit may be complicated and the circuit scale may be increased. In the present invention, in order to avoid this, the drive waveform information is selected based on the mark length of the binarized recording signal, the preceding space length and the mark length and the succeeding space length.
According to such a technical means, the optimum waveform of the drive waveform information is selected according to the space length and the mark length, so that the scale of hardware is reduced and the circuit scale can be reduced. According to a third aspect of the invention, the write control means is
It is also an effective means of the present invention to externally receive the drive waveform information and the address to be stored in the drive waveform information storage means by serial transfer, and write the drive waveform information in the drive waveform information storage means based on the address. Is. The drive waveform needs to be changed according to the material of the optical disk medium and the recording state. If this is to be realized by hardware, it is necessary to prepare circuits that generate various drive waveforms in advance. In the present invention, by receiving these drive waveform information from an external controller,
It is equipped with a means to store it. According to such a technical means, since the driving waveform information is received from the outside, the hardware can be minimized and a flexible circuit configuration can be realized.

According to a fourth aspect of the present invention, in an optical disc device equipped with a laser driving integrated circuit that sequentially switches a current supplied to a laser diode to a plurality of set levels, a binary recording signal to be recorded on a recording medium is provided. Correspondingly, drive waveform information storage means for storing at least one drive waveform information for driving the laser diode, address information of the drive waveform information storage means are stored, and the address information is stored in the drive waveform information storage means. Address information storage means for converting any one of them into an address, first-in first-out storage means for taking in the stored information of the driving waveform information storage means in synchronization with a clock signal, and for taking out in the order of the information taken in, first-in first-out means Current setting / switching means for controlling switching of the current level based on the stored information of the advance storage means, and recording in a recording medium 2 Address generation means for generating an address signal for selecting the address information of the address information storage means based on an encoded recording signal, and write control for storing drive waveform information supplied from the outside in the drive waveform information storage means. Means and are provided. Claim 1
Since the value of the third register is the upper bit and the value of the second register is the lower bit as the address signal, a large number of bits of the address signal are required. Therefore, in order to temporarily convert this address signal,
Further, an address information storage means for storing the address information of the drive waveform information storage means is provided. According to this technical means, since the address information storage means for storing the address information is provided, the number of bits of the address signal of the drive waveform information storage means can be reduced. The invention of claim 5 is
The address generating means selects an address for selecting the drive waveform information of the drive waveform information storage means based on the mark length, the preceding space length and the mark length and the following space length of the binarized recording signal. Generating a signal is also an effective means of the present invention. According to a sixth aspect of the present invention, the write control means receives the drive waveform information and the address to be stored in the drive waveform information storage means from the outside by serial transfer, and the drive waveform information is obtained based on the address. Writing in the drive waveform information storage means is an effective means of the present invention.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. However, the constituent elements, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely explanatory examples, not the gist of limiting the scope of the present invention thereto, unless specifically stated. ..

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a laser driving integrated circuit according to a first embodiment of the present invention and a controller section of an optical disk device equipped with the same (the optical system and mechanical system parts of the optical disk device are omitted). Reference numeral 1 denotes a controller, which is arranged on the fixed portion side (main substrate) of the optical disk device. Reference numeral 11 denotes a laser driving integrated circuit which is mounted on an optical pickup together with a laser diode 12 and is movable corresponding to a disc recording / reproducing track position.
The laser driving integrated circuit 11 includes mark / space length detecting means 4 for detecting the mark length and the space length from the binary recording signal NRZI supplied from the controller 1, and the mark / space length detecting means 4.
Based on the detection result of the space length detecting means 4, address generation is switched between outputting a value obtained by combining the mark length and the space length as an address signal, or outputting a common value independent of the mark length and the space length. Means 5,
A drive waveform storage unit 6 that outputs drive waveform information selected according to the output from the address generation unit 5, and a first-in first-out storage unit 7 that captures the output information of the drive waveform storage unit 6.
And a delay clock generation / selection means 8 for selecting a delay clock based on the output information of the first-in first-out storage means 7.
And setting the current values of a plurality of channels corresponding to the set value from the controller 1 and setting the current value for selecting one of the plurality of channels in synchronization with the delay clock from the delay clock generation / selection means 8.
Switching means 9 and driving means 10 for driving the laser diode 12 with current based on the output value from the current setting / switching means 9.
And the clock signal CLK supplied from the controller 1
Clock signal CLK (2f) obtained by multiplying (f / n) by 2n.
And the clock signal CLK (2f) is divided by two,
Clock signals CLK (f) and CLK (f /
2) clock generation means 3 for outputting, and controller 1
The write control means 2 writes the data supplied from the controller 1 into the drive waveform information storage means 6 and the current setting / switching means 9 by the address and the control signal supplied from the controller 1. Although the parallel transfer method is shown in FIG. 1 as a method of transferring data from the controller 1, it may be a serial transfer method of transferring data and an address by one signal line.

The operation of this first embodiment and the details of each section will be described below. FIG. 3 is a block diagram showing the configuration of the mark / space length detecting means 4, and FIG. 5 shows its operation timing. This configuration has a mark / space length detection counter 20 for counting the mark length (high level section) and space length (low level section) of the binarized recording signal NRZI, a timing generation means 24 for generating various timings, and a mark. Long or space length detection value,
Capture 1-bit information indicating mark or space
1 register 21, 2nd register 22, 2nd register 2
The third register 23 stores the mark length or space length supplied from 2 and 1-bit information indicating the mark or space. The operation will be described with reference to FIG. The mark / space length detection counter 20 has a mark length (high level section) and a space length (low level section) of the binarized recording signal NRZI supplied from the controller 1 by the clock CLK (f / 2).
Is counted. The first register 21 receives the timing signal from the timing generation means 24 and fetches the mark length or space length detection value and 1-bit information indicating the mark or space. Similarly, the second register 22 also takes in the mark length or space length detection value and 1-bit information indicating the mark or space, but when the count value of the mark space length detection counter 20 reaches 6, the mark This is a register for setting the mark length of 6 or more and the space length to 6 by taking in the count value 6 of the space length detection counter 20. The third register 23 fetches the mark length or space length supplied from the second register 22 and 1-bit information indicating the mark or space. FIG. 4 is a block diagram showing the internal configuration of the address generating means 5.
The address generation means 5 generates an address in which the drive waveform to be selected by the drive waveform information storage means 6 is stored, based on the values of the first to third registers. An address signal may be a value in which the value of the third register is the upper bit and a value in the second register is the lower bit (or a value in which the value of the second register is the upper bit and the value of the third register is the lower bit may be used as the address signal. The switch means 61 switches whether to output a common value that does not depend on the mark length and space length generated by the common address generation means 60 as an address signal.

FIG. 6 is a timing chart showing the relationship between the recording data and the laser diode drive current waveform. Clocks CLK (f / f) are shown in a), b), and c) of FIG.
2) shows recording data and a laser diode drive current waveform corresponding to the recording data. When the mark length is 6 or more, the same drive waveform is repeated in the middle of the mark, regardless of the mark length and the adjacent space length, the number of times corresponding to the mark length (repeating portion of the timing chart). Figure 6
In the case of the mark length 8 in c), it is repeated 4 times.
The common address generation means 60 of FIG. 4 generates a common value which does not depend on the mark length and the space length as an address signal corresponding to this repeated portion. In FIG. 7, the drive waveform information storage means 11 uses the value of the third register as the upper bit and the value of the second register as the lower bit as the address signal.
FIG. 3 is a diagram showing the relationship between the address and stored information. For example, in S3M4, the preceding space length is 3 and the mark length is 4
Drive waveform information corresponding to the combination of M4S3
Indicates drive waveform information corresponding to a combination in which the mark length is 4 and the following space length is 3. The drive waveform information corresponding to each combination is composed of four consecutive words having different lower 2 bits of the address.
Bits are omitted for simplicity. FIG. 10 is a diagram showing 12-bit drive waveform information for one word. b11
Is the mark start information, b10 is the mark end information, and b9 to b
4 is the upper 6 bits of the clock timing information, b3 to b
0 represents the lower 4 bits of the clock timing information. Here, the first-in first-out storage means 7 is the drive waveform information storage means 6
The drive waveform information output from is fetched in synchronization with the clock signal WCLK. The reading from the first-in first-out storage means 7 is performed in synchronization with the rising edge of the clock signal DCLK output from the delay clock generation / selection means 8. That is, when the clock signal DCLK rises,
The next drive waveform information is output from the first-in first-out storage means.
FIG. 8 is a block diagram showing the configuration of the delay clock generation / selection means 8. In this configuration, the phase comparator 30, the charge pump 31, the loop filter 32, and the variable delay line 33 are the delay locked loop (DL).
L), and compares the 6-bit counter 34 that counts the information (b11) indicating the beginning of the mark with the upper 6 bits (b9 to b4) of the clock timing information and whether the output value of the 6-bit counter 34 matches. It is composed of a decoder / comparator 35. Clock signal CLK (2
From f), as an output signal of the variable delay line 33, a clock signal CLK (2
f) A clock signal group (DCLK0
~ DCLK9) is generated. The 6-bit counter 34
After being initialized by the information (b11) indicating the beginning of the mark of the drive waveform information output from the first-in first-out storage means 7,
Counting is performed in synchronization with the clock signal CLK (2f). The decoder / comparator 35 includes the upper 6 bits (b9 to b4) of the clock timing information and the 6-bit counter 34 in the drive waveform information output from the first-in first-out storage means 7.
Of the selectors 3 are compared, and the lower 4 bits of the clock timing information are decoded, and the selector 3
10 output from the variable delay line 33 via 6
One of the channel delay clocks is selected and the clock signal DCLK is output.

FIG. 11 is a block diagram showing the configurations of the current setting / switching means 9 and the driving means 10. This configuration corresponds to registers 41, 42, 43 for setting values corresponding to three current levels 1, 2, 3, a switch 44 for switching the current level set value, and a set value output from the switch 44. A digital-to-analog converter (D / A) 45 that outputs a voltage, an operational amplifier 46 that operates so that the input voltage and the voltage due to the current flowing through the resistor 48 become equal, P-type MOS transistors 47 and 49, and a resistor 48. To be done. Numbers 41 to 43 are registers for setting values corresponding to the three current levels 1, 2, and 3 of FIG. 6, respectively, and the values are set by the controller 1 before driving the laser diode. The current setting / switching means 9 causes the rising edge of the clock signal DCLK output from the delay clock generating / selecting means 8 and the mark end information (b10) output from the first-in / first-out storage means 7.
Switch the current level set value output from the switch 44. Digital-to-analog converter (D / A) 4
5 outputs a voltage corresponding to the set value output from the switch 44. Since the circuit composed of the operational amplifier 46 and the P-type MOS transistor 47 operates so that this input voltage and the voltage due to the current flowing through the resistor 48 become equal, a current proportional to the current setting value output from the switch 44 is generated. , P-type MOS transistors 47, 49 and resistor 48. Since the P-type MOS transistor 49 and the P-type MOS transistor 51 of the driving means 10 are mirror-connected, the P-type MOS transistor 49
A current amplified by the ratio of the channel widths of and 51 is output from the P-type MOS transistor 51 and drives the laser diode 12.

FIG. 2 is a block diagram showing the configuration of the second embodiment of the present invention. In the drawings, the same components are designated by the same reference numerals, and a duplicate description will be omitted. 2 is different from FIG. 1 in that address information storage means 1
This is the point where 3 is newly provided. In the first embodiment, the values of the second register and the third register are used as the address signals of the drive waveform information storage means 6 as they are, but the address information storage means 13 for storing the address information of the drive waveform information storage means 6 is used.
Is provided to select the storage information of the drive waveform information storage unit 6 after the address conversion, the number of bits of the address signal of the drive waveform information storage unit 6 can be reduced.

[0013]

As described above, according to the present invention, since the main circuit is constructed in a relatively simplified manner, the cost of the integrated circuit can be reduced when integrated. You can According to the second aspect, since the optimum waveform is selected for the drive waveform information according to the space length and the mark length,
The scale of hardware is reduced and the circuit scale can be reduced. According to the third and fifth aspects, since the driving waveform information is received from the outside, the hardware can be minimized and a flexible circuit configuration can be realized. Since the address information storage means for storing the address information is provided, the number of bits of the address signal of the drive waveform information storage means can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a laser drive integrated circuit according to a first embodiment of the present invention and a controller unit of an optical disk device mounting the same.

FIG. 2 is a block diagram showing a configuration of a laser driving integrated circuit according to a second embodiment of the present invention and a controller unit of an optical disk device mounting the same.

FIG. 3 is a block diagram showing a configuration of mark / space length detecting means of the present invention.

FIG. 4 is a block diagram showing an internal configuration of address generating means of the present invention.

FIG. 5 is an operation timing chart of the mark / space length detecting means of the present invention.

FIG. 6 is an operation timing chart of the address generating means of the present invention.

FIG. 7 is a diagram showing a relationship between addresses and storage information of a drive waveform information storage means of the present invention.

FIG. 8 is a block diagram showing a configuration of a delay clock generation / selection means of the present invention.

FIG. 9 is a timing chart of output signals of the variable delay line of the present invention.

FIG. 10 is a diagram showing 12-bit drive waveform information for one word of the present invention.

FIG. 11 is a block diagram showing current setting / switching means and driving means of the present invention.

[Explanation of symbols]

1 controller, 2 write control means, 3 clock generation means, 4 mark / space length detection means, 5 address generation means, 6 drive waveform information storage means, 7 first-in first-out storage means, 8 delay clock generation / selection means, 9
Current setting / switching means, 10 driving means, 11 laser driving integrated circuits, 12 laser diodes

Claims (6)

[Claims] 1. An optical disk device equipped with a laser driving integrated circuit for sequentially switching a current supplied to a laser diode to a plurality of set levels, the laser diode being adapted to correspond to a binary recording signal to be recorded on a recording medium. Drive waveform information storage means for storing at least one drive waveform information to be driven; first-in first-out storage means for taking in the stored information of the drive waveform information storage means in synchronism with a clock signal and for taking out in the order of the taken-in information; Drive of the drive waveform information storage means based on the current setting / switching means for controlling the switching of the current level based on the storage information of the first-in first-out storage means, and the binarized recording signal recorded on the recording medium. Address generating means for generating an address signal for selecting waveform information, and driving waveform information supplied from the outside are stored in the driving waveform information storage unit. Optical disc apparatus being characterized in that and a write control means for storing the. 2. The address generating means, based on the mark length of the binarized recording signal, the preceding space length, and the mark length and the following space length, drive waveform information of the drive waveform information storage means, respectively. The optical disk device according to claim 1, wherein an address signal for selection is generated. 3. The write control means externally receives drive waveform information and an address to be stored in the drive waveform information storage means by serial transfer, and stores the drive waveform information based on the address in the drive waveform information storage. The optical disk device according to claim 2, wherein the optical disk device writes the data in the means. 4. In an optical disc device equipped with a laser drive integrated circuit for sequentially switching a current supplied to a laser diode to a plurality of set levels, the laser diode is driven corresponding to a binary recording signal to be recorded on a recording medium. Drive waveform information storage means for storing at least one drive waveform information to be stored, address information of the drive waveform information storage means is stored, and the address information is selected from any one of the drive waveform information storage means. Address information storage means for converting into an address, first-in first-out storage means for taking in the stored information of the driving waveform information storage means in synchronization with a clock signal, and taking out in the order of the taken-in information, and stored information in the first-in first-out storage means Based on the current setting / switching means for controlling the switching of the current level based on the Address generating means for generating an address signal for selecting address information in the address information storage means, and write control means for storing drive waveform information supplied from the outside in the drive waveform information storage means. An optical disk device characterized by. 5. The address generating means, based on the mark length of the binarized recording signal, the preceding space length, and the mark length and the succeeding space length, drive waveform information of the drive waveform information storage means, respectively. The optical disk device according to claim 4, wherein an address signal for selection is generated. 6. The write control means externally receives drive waveform information and an address to be stored in the drive waveform information storage means by serial transfer, and stores the drive waveform information based on the address in the drive waveform information storage. 6. The optical disk device according to claim 5, wherein the optical disk device writes data in the means.