TW525157B - Current generation circuit and method - Google Patents

Abstract

A laser driving circuit, which is capable of generating a level driving current corresponding to more than three kinds of laser powers, is disclosed in the present invention. The circuit is provided with the first to third signal generation circuits 110, 120, 130 and a signal combination circuit 140. The first signal generation circuit 110 detects the present output level of a semiconductor laser 50 according to the photo-sensing signal Vp detected by the photo-detector 51 so as to generate the first driving current Ib corresponding to the biased power. The second signal generating circuit 120 generates a differential current Ibe that is smaller than the second driving current corresponding to the erasing power by the amount of the first driving current. The third signal generation circuit 130 generates a ratio current Ibw, which is obtained by multiplying the differential current Ibe with a specified fold factor. The fold factor is determined by the equation of: [(writing in power-biased power)-(erasing power-biased power)]. The signal combining circuit 140 combines the currents Ib, Ibe and Ibw corresponding to the operation mode so as to generate a driving current Id of semiconductor laser 50.

Description

525157 A7 B7 V. Description of the invention (i) Field of the invention The present invention relates to a current generating circuit for driving a laser driving circuit and a laser driving method, such as a semiconductor laser used in an optical disc device, and a current generating circuit therefor. method. BACKGROUND OF THE INVENTION First, a laser driving circuit is exemplified as a current generating circuit. Various optical disc devices are known, but in general, most optical disc devices have a recording function for recording data on the optical disc, an erasing function for erasing the data recorded on the optical disc, and a recording function The regeneration function of data regeneration. The optical disc device usually uses a semiconductor laser to irradiate the optical disc with the laser light to record, reproduce, or erase data. Generally, the laser power (laser output level) at the time of recording and the time of erasing differs during recording. The laser power during recording is higher than the laser power during erasing, and the laser power during erasing is higher than the laser power during regeneration. Figures 1 (A) and (B) are broken diagrams showing the laser light emitted by a semiconductor laser in an optical disc device when it is irradiated onto a phase-change optical disc to record data. Into the pulse waveform. Figure 1 (A) is a waveform diagram of the waveform change of the data for recording. The pulse width Twd represents the data length of the data for recording. Fig. 1 (B) is a waveform diagram showing the waveform (or intensity) of the laser light corresponding to the recording data shown in Fig. 1 (A). The writing data pulse during recording shown in Figs. 1 (A) and (B) is set to the minimum period of the writing pulse as T. Figure 1 (A) exemplifies the pulse width of the written data -4- This paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 2525157 Explanation of the five inventions (==:; = 'Minimum week_ The minimum pulse T, the maximum pulse amplitude Ttop is 0.5 x τ, 0 write 6: the pulse balance is reset (cleared) on the bias power ^ ^ = = = ΠΓ force rate (laser output bit The standard) is composed of three types, that is, the bias power level pb of the first level, the erasing power level Pe of the second level, and the writing power level Pw of the third level. It has a relationship of 0 < Pb < Pe < Pw. Fig. 2 is a block diagram illustrating an example of a laser driving circuit in an optical disc device. The laser driving circuit 90 shown in Fig. 2 has the i-th to the third signals The generating circuits 10, 20, 30, and the signal synthesizing circuit 40. The laser driving circuit 90 operates in cooperation with the semiconductor laser 50, the light receiving element 51, the current-voltage conversion circuit (I / V) 52, and the control device 60. And the semiconductor laser 50 emits a laser light for reading, erasing, and writing the optical disc data in the optical disc device. In other words, the optical disc device Contains: a semiconductor laser 50, a light receiving element 51, a current / voltage conversion circuit 52, a control device 60, and a laser driving circuit 90. The first signal generating circuit 10 includes: a sample and hold circuit (SHb) n, and a circuit Error addition (subtraction) circuit 12, loop filter (Lpb) 13 'voltage / current conversion circuit (V / Ib) 14, and target value setting circuit (SETb) for adding a target value (reference value) to the addition circuit 12 15. The second signal generating circuit 20 includes: a sample and hold circuit (SHe) 21, an addition (subtraction) circuit 22 for calculating the deviation, a loop filter (Lpe) 23, a voltage / current conversion circuit (V / Ie) 24, And add the target value (reference value) to -5 This paper size is applicable to China National Standard (CNS) A4 size (210X 297mm) Staple 525157 A7

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Ψ 525157 A7 B7 V. Description of the invention (4) [Table 1]

Lo Laser power Pb Pe Pw during erasing during reproduction Pb Pe Pw First SW circuit 41 ON OFF OFF Second SW circuit 42 OFF ON OFF Third SW circuit 43 OFF OFF ON The control device 60 responds to recording data Data length, and output a control signal Sc, so that the switching circuits 41 ~ 43 are controlled by ON / OFF. For example, the control device 60 outputs a control signal Sc for ON / OFF according to the recording data in FIG. 1 (A), so that the write pulse shown in FIG. 1 (B) is output by the semiconductor laser 50 . The light-receiving element 51 is composed of, for example, a photodiode that generates an electrical signal corresponding to light, and a negative voltage of the photodiode is pre-applied with a power supply voltage Vc, so the photodiode, namely The light receiving element 51 is reversely biased. The light receiving element 51 receives a portion of the laser light output from the semiconductor laser 50 and performs photoelectric conversion to generate a current sensing optical signal Ip corresponding to the intensity of the received laser light. The current / voltage conversion circuit (I / V) 52 converts the current (sexual) photosensitive signal Ip generated by the light receiving element 51 into a voltage (sexual) photosensitive signal Vp. The semiconductor laser 50 has the non-linear characteristics shown in Fig. 4 and can irradiate a bias power Pb, an erasing power Pe, and a writing power Pw to an optical disc (not shown). As shown in FIG. 4, the semiconductor laser 50 has a non-linear characteristic, and the bias power level Pb, the erasing power level Pe, and the writing power level Pw are linear. However, the temperature characteristics around the semiconductor laser 50 may vary, and this paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm)

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6 6525157 V. Description of the invention (The level of the Pe level. The operation of the second signal generating circuit 20 is the same as the operation of the first signal generating circuit ι0, and only the operation with the first signal generating circuit 10 is described below. Different points are described. The target setting circuit 25 generates a second target signal 325, which is the target value (reference value) of the output signal S21 of the sampling and holding circuit 21, and then outputs the second target signal S25 to the adding circuit 22. The third signal generating circuit 30 will generate a second driving current Iw, so that the photosensitive signal Vp becomes an output power which will make the semiconductor laser 50] Lo is a level of a writing power level Pw. The second signal generating circuit 3 The operation of 〇 is the same as the operation of the first signal generating circuit 10 described above, and only the differences from the operation of the first signal generating circuit 10 will be described below. The target setting circuit 35 will generate a third target signal 335, which is The target value (reference value) of the output signal S31 of the sample-and-hold circuit 31 is then output to the adder circuit 32 of the third target signal S35. The positive electrode of the semiconductor laser 50 is inputted from the signal combination The driving signal Id of the circuit 40 is grounded to the ground potential (JND.) The semiconductor laser 50 will emit laser light at a laser power Lo corresponding to the driving current ^ applied to the positive electrode. The circuit structure of the laser driving circuit 90 shown below is expected to be simplified. First, the first signal generating circuit 10 for generating the driving current lb for the bias power Pb, and the driving for generating the erasing power Pe The second signal generating circuit 20 for the current Ie, and the drive for generating the writing power Pw-9- This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 525157 A7 B7 V. Description of the invention (7) Although the third signal generating circuit 30 of the current Iw operates independently, it is expected to be simplified because the circuit configuration is similar. Second, the signal synthesis circuit 40 has three to select the driving currents lb, Ie, and Iw. The switching circuits 41 to 43 used are also expected to simplify the circuit configuration. Moreover, although the laser drive circuit used in the optical disc device is exemplified as the current generating circuit of the present invention, it is not limited to the laser drive And other current generating circuits are expected to overcome the same problems as described above. OBJECTS AND SUMMARY OF THE INVENTION A first object of the present invention is to construct a circuit of a current generating circuit that outputs three or more driving currents having a linear relationship. Simplification. A second object of the present invention is to provide a method that can be used by the current generating circuit. A third object of the present invention is to provide an optimal optical disc device using the current generating circuit as a laser driving circuit. According to a first aspect of the present invention, there is provided a current generating circuit including: a first signal generating circuit having a non-linear characteristic, and inputting a signal indicating an operation state of a driving device using a linear characteristic portion, and A first driving current is generated according to a first target value, and the first driving current causes the output power of the driving device indicated by the signal indicating the operating state to become a first power level; a first Two signal generating circuits will input the signal indicating the operating state of the driving device, and then A second target value, and a modified second drive current is generated, and the modified second drive current is smaller than a second drive current. The first drive current CNS) A4 size (210 X 297 mm)

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Line flow, and the second driving current will cause the output power of the driving device indicated by the signal indicating the operating state to become a second power level higher than the first power level; a first A three-signal generating circuit for multiplying the modified second driving current by a specific multiple to generate a modified second driving current, and the modified third driving current is smaller than a third driving current by the- The amount of driving current, and the third driving current will cause the output power of the driving device to become a third power level higher than the second power level, and a signal synthesizing circuit for selecting the A first switching circuit for generating the output signal of the third loop number, a second switching circuit for selecting the output signal of the first loop number generating circuit, and a signal selected by the first switching circuit, the first switching circuit An addition circuit for adding a signal selected by the two switching circuits and an output of the first signal generating circuit, and applying the addition result to the driving device; wherein, in a first operation mode; The first and second switching circuits are 0FF; in a second operation mode, the first switching circuit is ON, and the second switching circuit is OFF. In the second operation mode, the first switching circuit Is 0, and the second switching circuit is in the ON state. The signal synthesizing circuit may further include a second addition circuit for adding the signal selected by the = switching circuit to the signal selected by the second switching circuit and outputting it to the addition circuit. The specific magnification is specified as follows: (second power level-first power level) / (second power level-first power level) According to a second aspect of the present invention, a laser driving circuit is provided,- 11-This paper size applies Chinese National Standard (CNS) Α4ϋ ^ × 297mm) 525157 A7 B7 V. Description of the invention (including: a first signal generating circuit, which will input a light-receiving k-number of the light-receiving element) and the light-receiving The signal is generated by the light receiving element in response to light emitted by a semiconductor laser. The circuit generates a first semiconductor laser driving current according to the first target value, and the first semiconductor laser driving current causes the The output power of the semiconductor laser indicated by the photosensitive signal becomes the first power level. A second signal generating circuit will input the photosensitive signal, and then generate a modified second drive according to a second target value. And the modified second drive current is smaller than a second semiconductor laser drive current, the first semiconductor laser drive current amount, and the second semiconductor laser drive current causes the The output power of the semiconductor laser indicated by the photosensitive signal is a second power level higher than the first power rate level, and a third signal generating circuit is used for the modified second driving current. Multiplied by a specific multiple to generate a modified third drive current, and the modified third drive current is smaller than a third semiconductor laser drive current, the first semiconductor laser drive current amount, and the third semiconductor The laser driving current = the output power of the semiconductor laser, which becomes a third power level higher than the second power level; and a signal synthesis circuit having a circuit for selecting the second signal generating circuit. A first switching circuit for outputting a signal, a second switching circuit for selecting an output signal of the second signal generating circuit, and a signal selected by the first switching circuit and a k number selected by the second switching circuit And an addition circuit that adds to the output of the first signal generating circuit, and 豸 the result of the addition is applied to the semiconductor laser; wherein in the 胄 action mode, the first and second switching circuits are 0. FF ’In the 动作 -action mode, the first-switching circuit is ON, -12-

525157 A7 B7 5. Description of the invention (10) The second switching circuit is OFF; in a third operation mode, the first switching circuit is OFF and the second switching circuit is ON. The signal synthesizing circuit may further have a second adding circuit for adding the signal selected by the first switching circuit and the signal selected by the second switching circuit, and then outputting it to the adding circuit. Preferably, the laser driving circuit is used in an optical disc device, and the laser light emitted by the semiconductor laser irradiates the phase change optical disc and the light receiving element; the first power level is biased Piezo power level; the second power level is an erasing power level for erasing data recorded on the optical disc; the third power level is an erasing power level for recording data on the optical disc The write power level; the first operation mode refers to a mode in which the semiconductor laser is driven at the bias power level; the second operation mode refers to the semiconductor laser in which the erase power level is driven Mode; the third operation mode refers to a mode in which the semiconductor laser is driven at the write power level; and the first and second switching circuits will be ON / OFF corresponding to erasing pulse waveforms and writing waveforms OFF. According to a third aspect of the present invention, there is provided an optical disc device having: a phase change optical disc; a pair of semiconductor lasers irradiated with laser light by the disc; a light receiving element for generating an emitted light corresponding to the semiconductor laser A light sensing signal; a control device for controlling a data read from the optical disc, a data erase from the optical disc, and a pair of data write from the optical disc; and the above laser drive circuit. The control device turns off the first and second switching circuits in the data reading mode; turns off the second switching circuit in the erasing mode, and makes the first switching circuit correspond to the erasing mode. -13- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) binding

Line 11 V. Description of the invention (0N / 0FF except for the waveform; in the writer mode, 'the first switching circuit is turned off, and the second switching circuit is turned on by the waveform in response to the writing waveform. According to a fourth aspect of the present invention, a laser driving device is provided. The first pseudo number generating device includes a photosensitive # number from a light receiving element, and the light sensing signal is generated by the light receiving element in response to a semiconductor laser. The emitted light is generated, and the circuit generates a first semiconductor laser drive current according to the first target value, and the first semiconductor laser drive current causes the semiconductor laser indicated by the light sensing signal to The output power becomes the -power level;-the second money generating device will input the photosensitive letter $ 'and then generate a modified second drive motor based on a third target value: and the modified second The driving current is smaller than a second semiconductor laser driving current by the first semiconductor laser driving current amount, and the second semiconductor laser driving current causes the output power of the semiconductor laser indicated by the photosensitive signal, become A second power level higher than the first power level, the first signal generating means is used for multiplying the modified second driving current by a specific multiple to generate a modified third driving current, And the modified third drive 1 current is smaller than a third semiconductor laser drive current. The first semiconductor laser drive current amount, and the third semiconductor laser drive current makes the output power of the + conductor laser. "" Is a third power level higher than the second power level; and a signal synthesizing device having a first switching device for selecting an output signal of the third signal generating device, and one for selecting A second switching device that outputs a signal from the second signal generating device, and a signal selected by the first switching device, a signal selected by the second switching device, and an output of the first signal generating device -14- This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 public director) 525157 A7 B7 V. Description of the invention (12) Adding device and applying the addition result to the semiconductor laser; among them, In a first action mode, the first and second switching devices are OFF; in a second action mode, the first switching device is ON, and the second switching device is OFF; in a third action mode Next, the first switching device is OFF, and the second switching device is ON. The signal synthesizing device also has a second addition device for switching the signal selected by the first switching device with the second switching device. The signals selected by the device are added and output to the adding device. According to a fifth aspect of the present invention, an optical disk device is provided, which includes: a phase change optical disk; a pair of semiconductor lasers that irradiate laser light with the optical disk; A light-receiving element for generating a light-sensitive signal corresponding to the emitted light of the semiconductor laser; a control device for controlling a data read from the optical disc, a data erasure from the optical disc, and a pair of the Data writing of optical discs; and the above-mentioned laser drive device. The control device turns off the first and second switching devices in the data reading mode; turns the second switching device to the OFF state in the erasing mode, and makes the first switching device correspond to the erasing mode. ON / OFF except for the waveform; in the write mode, the first switching device is turned OFF, and the second switching device is turned ON / OFF in response to the written waveform. According to a sixth aspect of the present invention, a laser driving method is provided, including: (a)-an input step for inputting a photosensitive signal from a light receiving element, and the light receiving signal corresponds to a semiconductor laser by the light receiving element (B)-each drive current generating step is used to generate a first semiconductor laser drive current according to a first target value, and the first semiconductor laser drive current causes the subject The semiconductor signal indicated by this sensor signal-15- This paper size is applicable to China National Standard (CNS) A4 specification (210X297mm)

Line 13) V. Description of the invention (The output power of the laser becomes the first value μ, and then according to the "first: target current ratio-4th = second drive current" and the second drive current of the modified drive current is smaller than the- The 3 laser driving current indicated by the semiconductor laser light sensing signal will multiply the current received by the current; and then the second driving of the correction will be-the second half driving current ratio is smaller than the third semiconductor laser driving current. == the amount of radiation drive current 'and the third semiconductor laser drive rate: the output power of the quasi-two-body laser' becomes -than the second work-the first-turn: two power levels; and the first output step 'its will In the -th-ΓΙ mode, the first semiconductor laser driving current is output; in the ::: operation mode, the first semiconductor laser driving current is added to the modified-driving current and output; in a first In the three-action mode, the semiconductor laser drive current and the modified third drive current are added together and output. The drawing briefly illustrates the above-mentioned object and features of the present invention. The present invention is described below with reference to the attached drawings *. The examples will be clearer. Figure 1 -Waveform diagram, exemplifying the laser power of a semiconductor laser when the laser light from a semiconductor laser in an optical disc device is irradiated onto a phase-change optical disc to record data. FIG. 2 is a block diagram illustrating an example Laser driving circuit in the light source device. Figure 3 is a block diagram showing a current generating circuit as disclosed in the present invention. -16- This paper size applies to China National Standard (CNS) A4 specification (21〇X 297) ) 525157 A7 B7 V. Description of the Invention (14) --- The first embodiment of the exemplified laser driving circuit. Fig. 4 is a characteristic diagram exemplifying the characteristics of the semiconductor laser in Fig. 3. Fig. 5 is a block The figure shows a second embodiment of a laser driving circuit as an example of the current generation circuit of the present invention. FIG. 6 is a flowchart of a laser driving method. 'The laser driving circuit shown in FIG. 3 and FIG. 5 are shown. 50 semiconductor laser pattern number comparison description 51 light receiving element 52 current / voltage conversion circuit 110, 120, 130-third signal generating circuit 111, 121 112 '122 113, 123 sampling and maintaining circuit addition (subtraction) circuit loop Filter 11 4, 124, 134 voltage / current conversion circuit 115 '125 135 136 142' 143 144, 145 190 Id Lo target value setting circuit magnification setting circuit multiplication circuit switching circuit addition circuit laser driving circuit driving current laser power invention detailed description- 17- This paper size is in accordance with China National Standard (CNS) A4 specification (2i0X 297 male f) 525157 A7 B7 Five invention description (hereinafter, referring to the attached drawings, the preferred embodiment of the current generating circuit of the present invention will be described The preferred implementation of the current generating circuit of the present invention is described with reference to a laser driving circuit used in, for example, the above-mentioned optical disc device. The circuit has, for example, a non-linear characteristic like a semiconductor laser, and can be provided in the use area with Three types of drive current in a linear relationship. From the following preferred embodiments, it will be understood that the current generating circuit of the present invention can provide a driving current to a device that has non-linear characteristics but can provide three types of driving currents with a linear relationship in the use area, and is applicable to Various categories. First Embodiment FIG. 3 is a block diagram showing a first embodiment of a laser driving circuit as a preferred embodiment of a current generating circuit disclosed in the present invention.

The laser driving circuit 190 shown in the line diagram 3 is provided in a disc device as a recording medium for driving a semiconductor laser that generates a laser light for irradiating the phase-change optical disc. The optical disc device uses a phase change optical disc to write, erase, and reproduce data. The laser driving circuit 190 shown in FIG. 3 includes first to third signal generating circuits 110, 120, 130, and a signal combining circuit 140. The laser driving circuit 190 is linked with the semiconductor laser 50, the light receiving element 51, the current / voltage conversion circuit (I / V) 52, the control device 160, and the like, so that the semiconductor laser 50 emits an optical disc for use in the optical disc device. Laser light for reading data, erasing data, writing data, etc. In other words, the optical disc device has a semiconductor laser 50, a light receiving element 51, a current / voltage conversion circuit 52, and a control device-18. This paper size applies to the Chinese National Standard (CNS) A4 specification (210X 297 mm) 16525157 A7 B7 V. DESCRIPTION OF THE INVENTION (Set 160 and laser driving circuit 190. Semiconductor laser 50, light receiving element 51, current / voltage conversion circuit (I / V) 52, etc. are substantially the same as those described with reference to FIG. 2. First signal generating circuit 110 It is a circuit configuration substantially the same as the first signal generating circuit 10 described with reference to FIG. 2, and generates a bias current Ib as the first laser driving current according to the detection current Ip of the light receiving element 51. The signal generating circuit 110 includes a sampling and holding circuit (SHb) m, an addition (subtraction) circuit 112, a loop filter (LPb) 113, a voltage / current conversion circuit (V / Ib) 114, and a target value setting circuit (SETfe) 丨15. The second signal generating circuit 120 is basically the same as the second signal generating circuit 20 described with reference to FIG. 2, and generates a correction erasing (erasing) current Ibe based on the detection current & of the light receiving element 51, as The modified second laser driving current. Also, the modified erasing current Ibe is different from the erasing current described with reference to FIG. 2. The difference is that Ibe = Ie-Ib. Ib is generated by the first signal generating circuit u0. The bias current of the first laser driving current. Further, the second signal generating circuit 12 shown in FIG. 3 is different from the second signal generating circuit 20 shown in FIG. 2 and has an intermediate output signal applied to the third No. generating circuit 130. The second signal generating circuit 120 includes a sample-and-hold circuit (SHbe) m, an addition (subtraction) circuit 122, a loop filter (LPbe) 123, a voltage / current conversion circuit (V / Ibe) 124, and Target value setting circuit (SETbe) 125. The circuit structure of the third signal generating circuit 130 and the -19th described in FIG. 2-This paper size is applicable to China National Standard (CNS) A4 specifications (210 X 297 public treasure) " ------ Staple

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The three-signal generating circuit 30 is greatly different. The sample-and-hold circuit (SHbe) 31, the addition circuit 32, and the loop wave filter (LPbe) 33 in the third signal generating circuit 30 in FIG. 2 are erased, and the voltage / current conversion circuit (v / lbw) 134 is provided. A setting circuit (SETwa) 135 and a multiplication circuit i36. Also, the multiplication circuit 136 is applied with an output signal from a loop filter (LPbe) IB of the second signal generating circuit 120. Equipped with the third driving current for correction output from the second signal generating circuit 130

Ibw, which is different from the third driving current Iw described with reference to FIG. 2, is Ibw ^ Iw-Ib. The synthesis circuit 140 has two switching circuits 142 and 143 and two addition circuits 144 and 145. Compared with the signal synthesizing circuit 40 described with reference to FIG. 2, there is one less switching circuit.

The signal synthesizing circuit 140 combines the current signals lb, Ibe, and Ibw by the control corresponding to the control device 16 to generate a driving current id corresponding to the target semiconductor laser 50. Between the addition circuit 144 and the voltage / current conversion circuit 124, a switching circuit 142 is provided. A switching circuit 143 is provided between the adding circuit 144 and the voltage / current conversion circuit 134. The processing content of the control device 160 is different from that of the control device 60 shown in FIG. 2. The switching circuits 142 and 143 perform the following ON / OFF operations as shown in Table 2 based on a control signal Sc output by the control device 160 to specify the target value of the laser power Lo. -20- This paper size is in accordance with Chinese National Standard (CNS) A4 (210 X 297 mm) 525157 A7 B7 V. Description of the invention (Table 2)

Laser power during erasing and erasing during writing Lo Pb Pe Pw SW circuit 142 OFF ON OFF SW circuit 143 OFF OFF ON When the control device 160 is turned on, for example, it will output a control signal Sc to switch the circuit 142, The ON / OFF action of 143 causes the semiconductor laser 50 to output a write pulse as shown in FIG. 1 (B) corresponding to the recording data of FIG. 1 (A). When the semiconductor laser 50 is driven with the bias power Pb, that is, when data is to be reproduced from the optical disc, the control circuits 142 and 143 are switched to the OFF state by the control signal Sc output from the control device 160. As a result, the addition circuit 145 applies only the current signal lb output from the first signal generating circuit 110 to the semiconductor laser 50 as the driving current Id.

When the semiconductor laser 50 is driven with the erasing power Pe, the switching circuit 142 will be turned on and the switching circuit 143 will be turned off upon receiving the control signal Sc output from the control device 160. As a result, the addition circuit 145 will phase the current signal Ib outputted by the first signal generation circuit 110 with the second current signal Ibe outputted by the second signal generation circuit 120 through the addition circuit 144. The obtained result is added to the semiconductor laser 50 as a driving current I d. When the semiconductor laser 50 is driven with the write power Pw, the switching circuit 142 will be turned OFF and the switching circuit 143 will be turned ON upon receiving the control signal Sc output from the control device 160. As a result, the adding circuit 145 will output the current signal lb outputted by the first signal generating circuit 110 to -21-this paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 19 19 B7 V. Description of the invention (the output of No.-# 5 generating circuit 130 and the addition of the No. 5 motor through No. 5 of the adding circuit 144 are added to the semiconductor laser 5 'as a drive The current I d is the same as that described with reference to FIG. 2, and the light-emitting diode composed of, for example, a light-emitting diode is subjected to a power supply voltage Ve, that is, the light-receiving element 51 which is a light-emitting diode. Subject to reverse bias. After receiving the laser light output by the semiconductor laser 50, the light-optical element 51 will perform photoelectric conversion ', and generate a current sensing signal Ip corresponding to the intensity of the received laser light. The light 50 will emit a front light and a backlight. The front light is used to write data to the disc. The backlight is received by the light receiving element 51 for monitoring its level. The light receiving element 51 will always receive the semiconductor laser 50. Backlight Current / Electric The voltage conversion circuit (V / I) 52 converts the current light sensing signal Ip generated by the light receiving element 51 into a voltage light sensing signal Vp. The first signal generating circuit 110 generates a target value according to the target value setting and the target value of the circuit 115. The first driving current, that is, the bias current lb, will cause the output power Lo of the semiconductor laser 50 to be the bias power level Pb. In the first signal generating circuit 110, the sample-and-hold circuit 111 performs a countermeasure with a specific period. The photosensitive signal Vp is sampled and maintained, and an output signal S 111 representing a sample value is generated. The sampling and maintaining circuit 111 may use a bottom maintaining circuit. The target value setting circuit 115 generates a first driving current, and That is, the target value (or reference value) of the bias current lb, the signal S 115, and the -22- this paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 525157

A target signal S 115 is output to the adding circuit 112. The adding circuit 112 subtracts the first target signal S115 from the output signal S111 of the sample-and-hold circuit 111, and generates a difference signal mu (= S115-S111) with a meaning deviation. The loop filter 113 attenuates the high-frequency component of the difference signal S112, generates a filtered signal S113 that passes low-frequency components, and sends the filtered signal S113 to the voltage / current conversion circuit 114. The loop filter n3 is a low-pass filter. The voltage / current conversion circuit 114 is used to convert the filtered signal S 113 which is a voltage signal into a current bias signal lb. The second signal generating circuit 120 is used to generate a current signal (corrected erase current) Ibe (Ibe = Ie-Ib) which is a differential current, and the differential current is a ratio which will cause a semiconductor laser 50 as shown by the photosensitive signal Vp The output power 10 will become the second driving current Ie of the erasing power level Pe, and will also be smaller than the difference in the amount of the first driving current (the bias current signal I b). In the second signal generating circuit 120, the reason for generating a current signal (corrected erase current) Ibe smaller than the second drive current ie by only the first drive current (bias current signal) is that in the signal synthesis circuit In the addition circuit 145 in 140, the first driving current (bias current signal lb) output by the first signal generating circuit 110 is added to the current signal Ibe output by the second signal synthesizing circuit 120, and The driving current id of the semiconductor laser 50 is made the second driving current Ie. The circuit structure of the second signal synthesizing circuit 120 is similar to that of the first signal synthesizing circuit 110, and its circuit operation is the same as the above-mentioned first signal synthesizing. 21G x 297 public director) a " a 525157

The operation of the circuit 110 is the same. The sample-and-hold circuit m is used to specifically sample the photosensitive signal Vp 'and hold its value' to generate an output signal S121 representing the sampled value. The / target value setting circuit 125 is used to generate a second target signal S125 representing the target value of the current signal (corrected erase current) Ibe as a differential current, and output the first target signal S125 to the addition circuit. 22 As for the difference current, the difference is smaller than the second driving current Ie which causes the output power L0 of the semiconductor laser 50 to be the erasing power level Pe, and is also smaller than the amount of the first driving current (bias current signal lb). Current. The adding circuit 122 subtracts the output signal S121 of the sample-and-hold circuit 121 from the second target signal S125, and generates a difference signal S122 (= S125-S121) indicating the difference. The loop wave filter 123 attenuates the high frequency component of the differential § No. 8112, and generates a filtered signal S123 that passes the low frequency component, and then sends the filtered signal S 123 to the voltage / current conversion circuit 124 and the multiplication circuit 136. The loop filter 123 is a low-pass filter. The voltage / current conversion circuit 124 is used to convert the filtered signal S 123 from a voltage signal into a current signal Ibe. The third signal generating circuit 130 is configured to generate a proportional current (corrected write current) according to a signal S135 representing a magnification m of one of the magnification setting circuits 135. Ibw (Ibw = Iw-Ib) According to the signal Vp, the output power Lo of the semiconductor laser 50 will become the third driving current Iw of the writing power level Pw, and it will be smaller by the first signal generating circuit 110. -24- This paper size is applicable China National Standard (CNS) A4 (210 X 297 mm) binding

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The current of the first driving current lb. In the third signal generating circuit 130, a modified third drive current (or modified input drive current) signal Ibw of the first drive Refraction Th driving current Iw and U㈣ current lb is generated. The reason is that in the second method circuit 145 in the signal synthesizing circuit u0, the first driving current lb 'output by the first signal generating circuit 11o and the current signal output by the third signal synthesizing circuit m

Ibw adds up. In the second generation number generation circuit 130, the multiplication circuit 136 multiplies the filtered signal S123 output by the second signal generation circuit 120 by a magnification m shown by the output signal S135 of the magnification setting circuit 135, and generates One multiplication result signal S136. The magnification setting circuit 135 generates a magnification setting signal S135 indicating a magnification ❿ specified by the following formula, and outputs it to the multiplication circuit 136. m = (Pw-Pb) / (Pe-Pb). However, Pw is the writing power level of the semiconductor laser 50. Pb is the bias power of the semiconductor laser 50. Pe is the erasing power of the semiconductor laser 50. ... (1) The voltage / current conversion circuit 134 converts the multiplication signal S136 of the multiplication circuit 136 from the voltage signal to the current signal ibw. The positive electrode of the semiconductor laser 50 has a driving signal Id from the signal synthesizing circuit 14o. The negative electrode is grounded to a ground potential GND. The semiconductor laser 50 emits laser light at a laser power Lo corresponding to the driving current Id. -25- This paper size applies to China National Standard (CNS) A4 (210X 297mm)

Binding

525157 A7 B7

Fig. 4 is a characteristic diagram illustrating the characteristics of the semiconductor laser 50 in Fig. 3. The horizontal axis of the characteristic graph is the driving current Id, and the vertical axis thereof is the laser power L (). The characteristics of the semiconductor laser 50 may change according to temperature, environmental changes, etc. Such changes are represented by characteristic curves VIII and A2. Of course, the change in the characteristics of the semiconductor laser 50 is not limited to the two characteristic curves A1 and A2 illustrated in FIG. 4. Depending on the changes in temperature and environment, there may also be characteristic curves Aι and A2 or with the characteristic curve VIII.丨, A2 is similar to other characteristics shown in the characteristic curve. The laser driving circuit 19 shown in FIG. 3 drives a semiconductor laser 50 having a characteristic change according to the temperature and environmental changes shown in FIG. 4. The characteristic curve A1 has the following characteristics. When the driving current is ^^ b, the laser power Lo = Pb. When the drive current Id = Iei, the laser power Lo = Pe. When the driving current Id = Iwi, the laser power Lo == Pw. Under characteristic curve A2, there are the following characteristics: When the drive current Id = Ib2, the laser power Lo = Pb. When the driving current Id = Ie2, the laser power Lo = Pe. When the driving current Id == Iw2, the laser power Lo = Pw. In Figure 4, Ierlbflbei; IWi-IbflbWi; again, Ie2-

Ib2 = Ibe2; Iw2_Ib2 = Ibw2 〇 The driving currents Ibi and Ib2 are the output current lb of the voltage / current conversion circuit 114 in the first signal generating circuit 110 at the laser power Lo = Pb. The first signal generating circuit 11 in FIG. 3 detects a semiconductor laser 50 when the characteristic of the semiconductor laser 50 is a characteristic curve A1. When the semiconductor laser 50 is -26, the paper standard applies to China National Standard (CNS) A4. Specifications (210X297 mm)

Line 525157

The output power at that time, and then perform a feedback control so that the output current coincides with the first driving current Ih. Also, the first signal generating circuit 11 in FIG. 3 is used when the characteristic of the semiconductor laser 50 is the characteristic curve A2. The current output power of the semiconductor laser 50 is detected by the photosensitive element 51, and then a feedback control is performed to make the output current ib equal to the corresponding first driving current Ib2. The installation current Ibe ^ Ibes is the output current of the voltage / current conversion circuit 124 in the second signal generating circuit 120 at the laser power B = 0 = 1 ^. In the case where the characteristic of the semiconductor laser 50 is the characteristic curve A1, the second signal generating circuit 12 in FIG. 3 detects the output power of the semiconductor laser 50 at the time with the photosensitive element 51, and then performs a feedback control to make the output The current Ibe is equal to the differential current Ibei. In addition, in the case where the characteristic of the semiconductor laser 50 is the characteristic curve A2, the second signal generating circuit 120 in FIG. 3 detects the output power of the semiconductor laser 50 at the time with the photosensitive element 51, and then performs a feedback control so that The output current Ibe is equal to the differential current ibe2.

The driving currents IbW1 and Ibw2 are the output currents Ibw of the voltage / current conversion circuit 134 in the third signal generating circuit 130 at the laser power 10 = Pw. In the third signal generating circuit 13 in FIG. 3, when the characteristic of the semiconductor laser 50 is the characteristic curve A1, the output power of the semiconductor laser 50 at that time is detected by the photosensitive element 51, and then a feedback control is performed so that The output current Ibw is equal to the ratio 1bwi. In addition, in the third signal generating circuit 130 in FIG. 3, when the characteristic of the semiconductor laser 50 is the characteristic curve A2, the output power of the semiconductor laser 50 at that time is detected by the photosensitive element 51, and then a feedback control is performed so that The output current Ibw is equal to the proportional current ibW2. The characteristic curves Al and A2 of the semiconductor laser 50 will always be at 0 < L〇 -27- This paper size applies to the Chinese National Standard (CNS) A4 specification (21〇χ297 mm) 525157 A7 B7

The linear or substantial linearity is different from the linear inclination of the characteristic curves A1 and A2. Therefore, the following formula 2 will hold. That is, the ratio (Ibwi / Ibe〇i is equal to the ratio (IbwVIbe2) and is equal to the multiplication ratio m specified by the formula !, that is, (Pw-Pb) / (Pe-Pb).

Ibw1 / Ibei = Ibw2 / Ibe2 = (Pw-Pb) / (Pe-Pb) ..... (2) Using Equation 2, even if the characteristics of the semiconductor laser 50 are changed, it can be changed from The output current Ibeu Ibes of the voltage / current conversion circuit 124 in the second signal generation circuit 120 calculates the output currents lbWl, lbw2 of the voltage / current conversion circuit 134 in the third signal generation circuit 130. Further, by multiplying the input signal to the voltage / current conversion circuit 124 by the ratio (magnification) m shown in Equation 2, the input signal of the voltage / current conversion circuit 134 can be generated. Specifically, by setting the magnification ratio m 'shown by the output signal S135 of the magnification setting circuit 135 to the magnification ratio {(pw-pb) / (pe_ Pb)} specified in Equation 2, and in the multiplication circuit 136, Multiplying this magnification by the filtered signal S123 'can generate a multiplication signal S136 which is an input signal of the voltage / current conversion circuit 134. Compared with the laser driving circuit 90 shown in FIG. 3, the laser driving circuit 90 shown in FIG. 3 has a circuit structure more because the sampling and maintaining circuit and the loop filter are deleted, and the switching circuit of the signal synthesis circuit 140 is less. For simplicity. In the laser driving circuit 19 of FIG. 3, the filter signal S123 input to the voltage / current conversion circuit 124 is multiplied by the output of the magnification setting circuit 135 in the multiplication circuit 136 in the third signal generating circuit 130. Signal -28-This paper size applies Chinese National Standard (CNS) A4 specification (210 X 297 public director) 525157 A7 B7 V. Description of the invention (26) S135, and a multiplication signal S136 is generated, and then the multiplication signal S136 is generated Input to the voltage / current conversion circuit 134, so the ratio of the current Ibw to the current Ibe will be exactly the same as the magnification of Equation 2. Second Embodiment FIG. 5 is a structural diagram of a second embodiment of a laser driving circuit of the present invention. The laser driving circuit 190A shown in FIG. 5 omits the adding circuit 144 in the signal generating circuit 140 shown in FIG. 3, and directly inputs the outputs of the switching circuits 142 and 143 to the adding circuit 145a, and uses a signal synthesizing circuit 140A. The other circuit configurations are the same as those of the laser driving circuit 190 described with reference to FIG. 3. As described above, either of the switching circuits 142 and 143 is controlled by ON / OFF, and the other is turned OFF. Therefore, the outputs of the switching circuits 142 and 143 can be directly applied to the adding circuit 145a. With this, the circuit configuration of the laser driving circuit 190A of FIG. 5 will be simpler than that of the laser driving circuit 190 shown in FIG. 3. The third embodiment constitutes the first to third signal generating circuits 110, 120, and 130, and the signal synthesizing circuits 140, 140A of the laser driving circuits 190 and 190 A shown in FIG. 3 and FIG. However, these circuits can be implemented as software processing using a computer, signal processing using a digital signal processor (DSP), or dedicated signal processing integrated circuits. In this case, a computer or the like will perform signal processing of the circuit constituent elements shown in Figs. In the following, a description will be given on the occasion of using a computer, and the control device -29- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)

Line 27 V. Explanation of the invention (160 can also be realized by computer. Laser driving method Figures 6 (A) ~ (B) are flowcharts of laser driving method. It shows the implementation of Figure 3 with a computer, guessing, etc.) The processing of the laser driving circuit in Fig. 5 at the time. Step S 1 ·· Production of the light-receiving signal ^ The light-receiving unit 51 will receive a part of the semiconductor laser 5G output laser light and generate a current light-sensitive signal Ip. Current / Voltage The conversion circuit 52 converts the current light sensing signal Ip into a voltage light sensing signal Vp. Church S2: the driving current; ^ The signal processing system of the third signal generating circuits 11, 12, and 13 of FIGS. 3 and 5 Each of them stands and rides at the same time. When performing the operations of the first to third signal generating circuits 11 to 12, 12 and 13 as described below through the computer or the like, the first to third signals will be generated in sequence. The operations of the circuits nQ, 120, and 130 are performed almost completely at the same time in a computer, etc., so they are processed at high speed, and the calculation is performed in a sampling cycle, so they are essentially equivalent to being processed at the same time. First Processing of signal generating circuit, and The processing of the second signal generating circuit does not matter the context. However, since the second signal generating circuit uses the result of the second signal generating circuit to perform calculations, the processing of the third signal generating circuit is preferably performed in the second signal generating circuit. After the processing. As the processing of the first signal generating circuit 110, the computer calculates a first target letter representing the target value of the sampled value of the photosensitive signal Vp as described above. The paper size applies to Chinese national standards ( CNS) A4 specification (210 X 297 mm) 525157 A7 B7 Fifth invention description (28) No. S115, and a signal S111 used to indicate the sampling value of the photosensitive signal Vp, the difference between the two (S115-S111) Then, based on this difference, a first driving current corresponding to the bias power Pb, that is, a bias current is generated. As the processing of the second signal generating circuit 120, the computer calculates a value indicating the photosensitivity as described above. The difference between the second target signal S125, which is the target value of the sampled value of the signal Vp, and the signal S121, which is used to indicate the sampled value of the photosensitive signal Vp (S125-S121), and then based on the difference. Generate a first difference current corresponding to the erase power Pe which is smaller than the second drive current by the first drive current amount, that is, the corrected erase current. When processed as the third signal generating circuit 130, the computer will calculate an The difference (S125-S 121) obtained by the second signal generation circuit is multiplied by the value of the magnification m {(S125-S121) · (Pw_Pb) / (Pe-Pb)}, and then a correspondence is generated according to the result. The second differential current (proportional current) of the write power Pw is smaller than the third drive current by the first drive current ΐ. When using a computer, the above multiplication process is quite simple. Steps S3 and S4: operation mode determination The control device 160 detects the current operation mode in the optical disc device, and then applies a driving current corresponding to the mode to the semiconductor laser 50. The control device 160 determines whether a target value of the laser power Lo indicating that the operation mode of the optical disc device is a write mode is the write power Pw, and determines whether a target value of the laser power Lo indicating the erase mode is the erase power Pe. Modes other than these are bias modes. After the operation mode is determined, any of the following processing is performed. Step S5: Generation of write drive current -31-This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm).

• Line 525157 A7 B7 V. Description of the Invention (29) The control device 160 adds the first driving current lb and the modified third writing current Iwb so that the target value of the laser power Lo becomes the writing power Pw. Step S6: Generation of erasing driving current The control device 160 adds the first driving current lb and the modified second erasing current Ieb so that the target value of the laser power Lo becomes the erasing power Pe. Step S7: Generation of bias drive current. The control device 160 outputs only the first drive current lb, so that the target value of the laser power Lo becomes the bias power Pb. The control device 160 repeats the above processing. Further, in an optical disc device having a laser driving circuit 190, in the control device 160, the magnification is read from the optical disc in which the magnification data of the display formula 2 is recorded in advance, and the read magnification is set In the magnification setting circuit 135.

The optical disc may be, for example, a DVD-RW or DVD-RAM of a phase change type. The above embodiment is an example of the present invention, and the present invention is not limited to the above embodiment. For example, the above-mentioned laser driving circuit is not limited to being applicable only to an optical disc device. When three types of driving signals having a specific linear relationship are to be generated, the above-mentioned laser driving circuit may also be used as a current generating circuit. As described above, according to the present invention, it is possible to simplify a circuit configuration of a current generating circuit such as a laser driving circuit that causes a semiconductor laser to output three or more laser powers. As a result, for example, when the laser driving circuit of the present invention is used, the configuration of the optical disc device will be relatively simple. -32- This paper size is in accordance with Chinese National Standard (CNS) A4 specification (210 X 297 mm) 525157 A7 B7 Five invention descriptions (30 Also, according to the present invention, a current generating circuit or a current generating device can be provided Industrial applicability The laser driving circuit of the present invention is suitable as a semiconductor laser driving circuit in an optical disc device. In addition, the driving current generating circuit of the present invention has a non-linear characteristic like a semiconductor laser. , And can be used as a circuit to generate a current for driving a driving device used in a linear area. -33- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)

Claims (1)

525157 A8 B8 C8 l: A current generating circuit, including: a first signal generating circuit, which has non-linear characteristics, and will input a signal indicating the operating state of a driving device used in a linear region, and generate it according to a first target value A first driving current, and the first driving current will cause the output power of the driving device indicated by the signal indicating the operating state to become a first power level; a second signal generating circuit will input the indication The signal of the operating state of the driving device generates a modified second driving current according to the second target value, and the modified second driving current is smaller than the second driving current by the first driving current amount, and The second driving current will cause the output power of the driving device indicated by the signal indicating the operating state to become a second momentum level higher than the first power level; a second signal is generated The circuit is used to multiply the modified second driving current by a specific multiple to generate a modified third driving current, and the modified third driving current is smaller than one The third driving current is still smaller than the first driving current amount, and the third driving current makes the output power of the driving device 'a third power level higher than the second power level; and a signal The synthesizing circuit has a first switching circuit for selecting an output signal of the third signal generating circuit, a second switching circuit for selecting an output signal of the second signal generating circuit, and a first switching circuit An addition circuit for adding the selected signal, the signal selected by the second switching circuit, and the output of the first ^ th generation circuit, and applying the addition result to the driving device; wherein a first DY-34- This paper size is applicable to China National Standard (CNS) A4 (210X297 mm) 525157 A8 B8 C8 D8 In the patent application mode, the first and second switching circuits are OFF; in a second action In the mode, the first switching circuit is in the ON state, and the second switching circuit is in the OFF state. In a third operation mode, the first switching circuit is in the ON state, and the second switching circuit is in the ON state. The current generating circuit according to item 1 of the scope of patent application, wherein the signal synthesizing circuit further has a second addition circuit for selecting a signal selected by the first switching circuit and a signal selected by the second switching circuit. The signals are summed 'and output to the addition circuit. 3. The current generating circuit as described in item 1 or 2 of the patent application scope, wherein the specific magnification is specified as follows: ((second power level-first power level) / (second power level-first Power level). 4. A laser driving circuit including a first signal generating circuit that inputs a photosensitive signal from a light receiving element, and the photosensitive signal is generated by the light receiving element in response to light emitted by a semiconductor laser, The circuit generates a first semiconductor laser driving current according to the first target value, and the first semiconductor laser driving current makes the output power of the semiconductor laser indicated by the photosensitive signal become the first power. Level; the first No. 4 generating circuit will input the photosensitive signal, and then generate a modified second driving current according to a second target value, and the modified second driving current is driven by a second semiconductor laser The current is still smaller than the amount of the first semiconductor laser driving current, and the second semiconductor laser driving current will make the output power of the semiconductor laser indicated by the photosensitive signal -35- CNS) A4 size (210 X 297 mm) Patent application Rate to become a second power level higher than the first power level; a second signal generating circuit for multiplying the modified second driving current by a special multiple to generate a modified third driving Current, and the modified second driving current is smaller than a third semiconductor laser driving current, the first semiconductor laser driving current amount, and the third semiconductor laser driving current makes the output power of the semiconductor laser Becomes a third power level higher than the first power level; and a pseudo-number synthesizing circuit having a first switching circuit for selecting an output signal of the third signal generating circuit, and one for selecting A second switching circuit that outputs an output signal of the second signal generating circuit, and a signal selected by the first switching circuit, a signal selected by the second switching circuit, and an output of the first signal generating circuit An addition circuit, and applying the addition result to the semiconductor laser; wherein, in a first operation mode, the first and second switching circuits are OFF; in a second operation mode, the The first switching circuit is in the ⑽ state, and the second switching circuit is in the OFF state; in the -third operation mode, the -th switching circuit is 0FF 'and the second switching circuit is on. 5. The laser driving circuit as described in item 4 of the patent claim, wherein the signal synthesizing circuit further has a second addition circuit for adding the signal selected by the first switching circuit to the second switching circuit. The selected signals are added together and output to the adding circuit. 6. The laser drive circuit as described in item 4 or 5 of the scope of patent application, wherein the special magnification is specified as follows: (third power level—first power level) / • 36- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) 525157 (Second power level-first power level). The laser driving circuit according to item 4 or 5 of the scope of patent application, wherein the first signal generating circuit has: a first sampling and maintaining circuit for sampling the photosensitive signal; a first target value generating circuit Outputting the first semiconductor laser drive current as the first target value, and the first semiconductor laser drive current will cause the output power of the semiconductor laser directed by the photosensitive signal to become the first power level; A subtracting circuit is configured to subtract the first target value from the output signal of the first sample-and-hold circuit to generate a first difference signal; and output the first difference signal as the first driving current. 8 The laser driving circuit according to item 4 or 5 of the patent claim, wherein the second signal generating circuit has: a first sampling and maintaining circuit for sampling the photosensitive signal; a second target value generating circuit To output the modified second motor current as a second target value, and the modified second driving current is smaller than the second semiconductor laser driving current, the first semiconductor laser driving current amount, and the second The semiconductor laser driving current will cause the output power of the semiconductor laser indicated by the photosensitive signal to become a second power level higher than the first power level; a second subtraction circuit for The second target value subtracts the output signal of the second sample-and-hold circuit to generate a second difference signal; and the second difference signal is output as the second modified driving current. 9. The laser driving circuit as described in item 8 of the scope of the patent application, wherein the second -37- this paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm). The number generation circuit also has a A filter for passing a low-domain component of the second difference signal as an output of the subtraction circuit. 0 'The laser driving circuit as described in item 8 or 9 of the Shenjing patent, wherein the third signal generating circuit has: a rate generating circuit to output a rate for generating the modified third driving current And the modified third driving current is smaller than the third semiconductor laser driving current by the first semiconductor laser driving current amount, and the third semiconductor laser driving current makes the output power of the semiconductor laser, Become a third power level higher than the second power level; a multiplying circuit for multiplying the modified second driving current generated in the second signal generating circuit by one generated by the magnification The magnification output by the circuit; and the output of the multiplication result is used as the third driving current. 11. If the laser drive circuit of item 4 or 5 of the patent application scope, wherein the laser drive circuit is used in an optical disc device, and the semiconductor laser emits "the laser light will change the phase The first power level is the bias power level; the second power level is-the erasing power level for erasing the data recorded on the disc with α; the The third power level is a power level for recording data on the optical disc; * The first operation mode refers to a mode in which the semiconductor laser is driven at the bias power level; the second operation mode Means the mode for driving the semiconductor laser at the erasing power level 525157 A8 B8 C8 D8; the third operation mode means the mode for driving the semiconductor laser at the writing power level; The first and second switching circuits are ON / OFF corresponding to the erase pulse waveform and the write waveform. 12. An optical disc device, comprising: a phase change optical disc; a semiconductor laser irradiating laser light to the optical disc; a light receiving element for generating a photosensitive signal corresponding to the emitted light of the semiconductor laser; a control A device for controlling a reading of data from the optical disc, erasing of data from the pair of optical discs, and writing of data from the pair of optical discs; a first signal generating circuit that inputs a photosensitive signal from the light receiving element And according to a first target value, a first semiconductor laser drive current is generated, and the first semiconductor laser drive current causes the output power of the semiconductor laser indicated by the photosensitive signal to become a bias power Level; a second signal generating circuit will input the photosensitive signal, and then generate a modified second driving current according to a second target value ', and the modified second driving current is driven by a second semiconductor laser The current is also smaller than the amount of the first semiconductor laser driving current, and the second semiconductor laser driving current causes the semiconductor laser indicated by the photosensitive signal The output power becomes an erasing power level higher than the bias power level. A third signal generating circuit is used to multiply the modified second driving current by a specific multiple to generate a modified first power level. Three driving currents, and this -39- this paper size is applicable to Chinese National Standard (CNS) A4 specifications (210 X 297 mm) 525157 A8 B8 C8 D8, the third driving current for patent range correction is higher than a third semiconductor laser The driving current is also smaller than the amount of driving current of the first semiconductor laser, and the driving current of the third semiconductor laser will cause the output power of the semiconductor laser to become a higher writing power level than the erasing power level. And a signal synthesis circuit having a first switching circuit for selecting an output signal of the third signal generating circuit, a second switching circuit for selecting an output signal of the second signal generating circuit, and a An addition circuit for adding a signal selected by the first switching circuit, a signal selected by the second switching circuit ′ and an output of the first signal generating circuit, and applying the result of the addition To the semiconductor laser; and wherein the control device turns off the first and second switching circuits in the data reading mode; and turns off the second switching circuit in the erasing mode, The first switching circuit is turned ON / OFF corresponding to the erasing waveform; in the writing mode, the first switching circuit is turned OFF, and the second switching circuit is turned ON / OFF in response to the writing waveform. 13. The optical disc device according to item 12 of the scope of patent application, wherein the signal synthesizing circuit further has a second addition circuit for selecting a signal selected by the first switching circuit and a signal selected by the second switching circuit. The signals are added and output to the adding circuit. 14. The optical disc device according to item 12 or 13 of the scope of patent application, wherein the specific magnification is specified as follows: (third power level-first power level) / (second power level-first power level) quasi). -40- This paper size is applicable to China National Standard (CNS) A4 (210X297 mm) Binding 15. A laser driving device comprising: a first signal generating device that inputs a photosensitive signal from a light receiving element, and the photosensitive signal is generated by the light receiving element in response to light emitted by a semiconductor laser, the The circuit generates a first semiconductor laser driving current according to the first target value, and the first semiconductor laser driving current makes the output power of the semiconductor laser indicated by the photosensitive signal become the first power level. A second signal generating device will input the photosensitive signal, and then generate a modified second drive current based on a second target value, and the modified second drive current is greater than a second semiconductor laser drive current The amount of the first semiconductor laser driving current is also reduced, and the second semiconductor laser driving current will make the output power of the semiconductor laser indicated by the photosensitive signal higher than the first power level The second power level; the second “§ generating device” is used to multiply the modified second drive current by a specific multiple to generate a modified third drive Current, and the modified third driving current is smaller than a third semiconductor laser driving current, the first semiconductor laser driving current amount, and the third semiconductor laser driving current makes the output power of the semiconductor laser Becomes a third power level that is further south than the first power level; and a k-number synthesizing device having a first switching device for selecting an output signal of the third signal generating device and a for selecting A second switching device that outputs a signal from the second signal generating device, and a signal selected by the first switching device, a signal selected by the second switching device, and an output of the first signal generating device Adding device, and -41-t SS household materials (CNS) A4 secret _ x 297 public director)-: ---------- 525157 A8 B8 C8 D8 The result is applied to the semiconductor laser; wherein, in a first operation mode, the first and second switching devices are OFF; in a second operation mode, the first switching device is in an ON state, and the first Two switching devices are OFF; one The three operation modes, the first switching means is 〇FF, and the second switching means is 〇N state. 16. The laser driving device according to item 15 of the scope of the patent application, wherein the signal synthesizing device further has a second adding device for adding the signal selected by the first switching device to the second switching device. The selected signals are added and output to the adding device. 17. The laser driving device as described in item 15 or 16 of the patent scope of the application, wherein the specific magnification is specified as follows: (the third power level-the first power level) / (the second power level-the first One power level). 18 · —An optical disc device having: a phase change optical disc; a semiconductor laser that irradiates laser light to the optical disc; a light receiving element for generating a photosensitive signal corresponding to the emitted light of the semiconductor laser; a control A device for controlling a data read from the optical disc, a data erase of a pair of the optical discs, and a data write of a pair of the optical discs; a first signal generating device for inputting a photosensitive signal from the light receiving element And according to a first target value, a first semiconductor laser driving current is generated, and the first semiconductor laser driving current causes the output power of the semiconductor laser indicated by the photosensitive signal to become a bias work. -42- This paper size is applicable to China National Standards (CNS) A4 specifications (21 × 297 mm) 525157 A8 B8 C8 D8 Six patent application rate range level; a second signal generating device will input the light sensitive signal, According to a second target value, a modified second driving current is generated, and the modified second driving current is smaller than a second semiconductor laser driving current. Volume of the laser driving current, and the second semiconductor laser driving current will make the output power of the semiconductor laser indicated by the photosensitive signal become an erasing power level higher than the bias power level A third signal generating device for multiplying the modified second driving current by a specific multiple to generate a modified third driving current, and the modified third driving current is smaller than a third semiconductor laser The driving current is also smaller than the amount of driving current of the first semiconductor laser, and the driving current of the third semiconductor laser will cause the output power of the semiconductor laser to become a higher writing power level than the erasing power level. And a signal synthesizing device having a first switching device for selecting an output signal of the third signal generating device, a second switching device for selecting an output signal of the second signal generating device, and a An addition device for adding a signal selected by the first switching device, a signal selected by the second switching device, and an output of the first signal generating device, and adding the result Added to the semiconductor laser; and wherein the control device turns off the first and second switching devices in the data readout mode; and turns off the second switching device in the erasing mode And make the first switching device ON / OFF corresponding to the erasing waveform; in the write mode, make the first switching device be OFF, and make the -43- this paper size apply the Chinese National Standard (CNS ) A4 size (210 X 297 mm) k order 525157 A8 B8 C8 __________D8 6. Scope of patent application 2. The switching device is 0N / 〇FF in response to the written waveform. 19. The light material arrangement as described in item 18 of the China National Materials Association, wherein the signal synthesizing device further includes a second addition device for adding the money selected by the first switching device to the second switching device. The selected signals are added and output to the adding device. 20. The optical disc device described in claim 18 or 19, wherein the specific magnification is specified as follows: (second power level-first power level) / (second power level-first power level) Level). 21. —A laser driving method, comprising: an input step for inputting a light receiving signal from a light receiving element, and the light receiving signal is generated by the light receiving element in response to light emitted by a semiconductor laser; A driving current generating step for generating a first semiconductor laser driving current according to a first-target value, and the first semiconductor laser driving current causes the output power of the semiconductor laser indicated by the photosensitive signal Become the first power level; according to a second target value, a modified second drive current is generated, and the modified second drive-second semiconductor laser drive current is still smaller than the first semiconductor laser: Current, and the second semiconductor laser driving current will cause the output power of the semiconductor laser indicated by the photosensitive signal to be a second power level with a high power level; : The dynamic current is multiplied by a specific multiple to produce—the modified third drive current, and the modified third drive current ratio—the third half of the laser drive—44- This paper size applies to China Standard (CNS) A4 specification (210X297 mm) " ---- 525157 Six A8 B8 C8 D8 Patent application scope The current is still smaller than the first semiconductor laser driving current while the third semiconductor laser driving current will be The output power of the semiconductor laser is set to a third power level higher than the second power level; and an output step is to output the first semiconductor laser drive in a first operation mode. Current; in a second action mode, the first semiconductor laser drive current is added to the modified second drive current and output; in a third action mode, the first semiconductor laser drive current is added The modified third driving current is added and output. -45- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)