CN1224145C - Automatic laser power control circuit and its switch control circuit - Google Patents
Automatic laser power control circuit and its switch control circuit Download PDFInfo
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- CN1224145C CN1224145C CNB021426457A CN02142645A CN1224145C CN 1224145 C CN1224145 C CN 1224145C CN B021426457 A CNB021426457 A CN B021426457A CN 02142645 A CN02142645 A CN 02142645A CN 1224145 C CN1224145 C CN 1224145C
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Abstract
The present invention relates to an automatic laser power control circuit and a switch control circuit thereof. The automatic laser power control circuit comprises a feedback circuit and a switch control circuit, wherein the switch control circuit comprises a first electronic switch, a second electronic switch, a third electronic switch, a fourth electronic switch and a resistor. When a first control signal is energized, the first electronic switch and the third electronic switch are switched on, the second electronic switch and the fourth electronic switch are closed, and signals of the feedback amplification circuit are connected to a driving circuit. Thereby, a laser diode is driven. When the first control signal is not energized, the second electronic switch and the fourth electronic switch are switched on, and the first electronic switch and the third electronic switch are closed. The present invention utilizes a power supply formed on the driving circuit by the resistance to prohibit the driving circuit and the laser diode is completely closed.
Description
Technical field
The present invention relates to a kind of control circuit of laser diode, and be particularly related to a kind of automatic laser power control circuit and ON-OFF control circuit.
Background technology
The laser diode driver circuit of present CD driver, all be to utilize an automatic laser power control circuit (Auto Laser Power Control, be called for short ALPC) the switch inside control circuit, activate (activation) or, just be used for opening or closing laser diode by the drive circuit of (forbidden energy) laser diode.With reference to figure 1, Fig. 1 is the circuit diagram that concerns of the ON-OFF control circuit of common laser diode automatic laser power control circuit and whole laser diode drive system.Laser diode 141 is optically coupled to light sensitive diode 111, that is to say, light sensitive diode 111 can convert the luminous intensity that light-emitting diode 141 is sent to electrical signals, carries out closed-loop control by feedback amplifier again, to reach the purpose of power control.Wherein, the power vd D1 that is made in laser diode driver circuit 304 on common automatic laser power control circuit 303 and the printed circuit board (PCB) in the chip in some cases is 5 volts.When control signal LDEN is high potential, the 161 not conductings of P transistor npn npn, utilize the formed bias circuit of laser diode driver circuit 304 power vd D1, and transistor 171 is moved, inductance 131 has electric current to flow through, and makes laser diode (Laser Diode) 141 tool lasing fluorescence characteristics; When control signal LDEN is electronegative potential, transistor 161 conductings, common ON-OFF control circuit 302 power vd D2 are at the current potential of node Y1 ON-OFF control circuit 302 power vd D2 no better than, just can not form a bias circuit and transistor 171 is ended, its collector terminal does not have electric current to flow out, and laser diode 141 is not had a lasing fluorescence characteristic.
But since at present circuit in design service speed require more and more highly, and that the power that consumes also requires is fewer and feweri, therefore needed power values also reduces naturally.Perhaps, because the manufacturing process reduction, some power supply also need and then be used less power supply on the chip.Also because so, needed power supply on the automatic laser power control circuit just might use less power supply.For instance and with reference to figure 1, if needed power vd D2 changes 3.3 volts into by 5 volts on the automatic laser power control circuit, when control signal LDEN was high potential, the entire circuit running was out of question; When control signal LDEN is electronegative potential, node Y1 current potential (3.3 volts) has pressure reduction with the current potential (5 volts) of laser diode driver circuit 304 power vd D1, the electric current that offers laser diode 141 this moment still has tens of milliamperes (current gain of supposing the positive-negative-positive BJT transistor 171 in the laser diode driver circuit 304 is 250, and then the operating current by laser diode still has 14.4325mA).This operating current can make that just laser diode is not to close fully and have the characteristic of LED.Thus, laser diode 141 will be incomplete because of what close at every turn, causes reduce its useful life.
Summary of the invention
The objective of the invention is to propose a kind of automatic laser power control circuit and ON-OFF control circuit thereof, under the situation of automatic laser power control circuit and drive circuit different electrical power, can prolong the life-span of its use so that laser diode is closed completely.
The invention discloses a kind of automatic laser power control circuit, it accepts the luminous intensity feedback signal and the optical coupling signal of photoinduction circuit, with control Driver Circuit, and then the driving laser led lighting.This automatic laser power control circuit comprises at least: feedback amplifier and ON-OFF control circuit.Feedback amplifier wherein is coupled to above-mentioned photoinduction circuit, in order to accept and according to the optical coupling signal, to come correct driving laser led lighting.This feedback amplifier is also accepted above-mentioned luminous intensity feedback signal, to adjust the luminous power of laser diode emission.Above-mentioned ON-OFF control circuit is coupled to first power supply, drive circuit and above-mentioned feedback amplifier, in order to accept the control of first control signal, comes activation or forbidden energy drive circuit.When the first control signal forbidden energy, this ON-OFF control circuit makes feedback amplifier be not attached to drive circuit, and provide an equivalent resistance, make above-mentioned first power supply be connected to drive circuit, and then make drive circuit not provide electric current to laser diode through this equivalent resistance.
ON-OFF control circuit provided by the present invention is applied in the automatic laser power control circuit in the laser diode drive system, this ON-OFF control circuit is coupled to drive circuit and feedback amplifier, and this ON-OFF control circuit comprises: first electronic switch, second electronic switch, the 3rd electronic switch, quadrielectron switch and resistance.Above-mentioned these electronic switches all have first link, second link and control end at least.Wherein first link of first electronic switch is coupled to feedback amplifier, first link of second electronic switch is coupled to first power supply, second link of the 3rd electronic switch is coupled to drive circuit, and first link of second link of second link of first electronic switch, second electronic switch, the 3rd electronic switch and first link of quadrielectron switch are coupled in together.Above-mentioned resistance has first end and second end equally, and first end of this resistance is coupled to second link of quadrielectron switch, and second end of this resistance is coupled to second link of the 3rd electronic switch.
Above-mentioned first electronic switch, second electronic switch, the 3rd electronic switch and quadrielectron switch control end separately are coupled to first control signal.When this first control signal activation, this ON-OFF control circuit can make first electronic switch and the 3rd electronic switch conducting, and second electronic switch and quadrielectron switch are closed, so the signal of feedback amplifier can be connected to drive circuit.When the first control signal forbidden energy, this ON-OFF control circuit can make second electronic switch and quadrielectron switch conduction, and first electronic switch and the 3rd electronic switch are closed, so first power supply is connected to drive circuit through this resistance, and then make drive circuit not provide electric current to laser diode.
The ON-OFF control circuit that is provided in the preferred embodiment of the present invention, wherein this second electronic switch uses the first transistor, and the 3rd electronic switch system uses transistor seconds, and the first transistor is different with the kenel of transistor seconds, and it is that the first transistor, N type MOS transistor are transistor seconds that present embodiment is selected P type MOS transistor especially for use.And first electronic switch in the preferred embodiment of the present invention is first transmission gate, and quadrielectron switch is second transmission gate, and this first transmission gate and second transmission gate are also accepted the control of second control signal, and this second control signal and first control signal are anti-phase.In preferred embodiment, when first control signal is high potential, first transmission gate and transistor seconds conducting, and the first transistor and the second not conducting of transmission gate.When first control signal is electronegative potential, the first transistor and the second transmission gate conducting, first transmission gate and not conducting of transistor seconds.
In sum, the present invention is with the ON-OFF control circuit of four electronic switches and a resistance formation automatic laser power control circuit.Wherein utilize resistance formed power supply on drive circuit, this drive circuit of forbidden energy makes laser diode cut out fully.Be the present invention can so that laser diode under its automatic laser power control circuit situation different, can close completely, and then prolong the life-span of its use with the power values of drive circuit power supply.
The present invention also provides a kind of ON-OFF control circuit, be applied to the automatic laser power control circuit in the laser diode drive system, this ON-OFF control circuit is coupled to an one drive circuit and a feedback amplifier, it is characterized in that, comprise: a switching device, has first link, second link, the 3rd link, the 4th link and an activation control end, this activation control end receives one first control signal, first link of this switching device is coupled to one first power supply, second link of this switching device is coupled to this feedback amplifier, and the 4th link of this switching device couples this drive circuit in a node; And a damping, having first link and second link, first link of this damping couples the 3rd link of this switching device, and second link of this damping is coupled to this node; When this first control signal activation, make the 3rd link conducting of first link and this switching device of this switching device, and the 4th not conducting of link of second link of this switching device and this switching device, when this first control signal forbidden energy, make the 4th link conducting of second link and this switching device of this switching device, and the 3rd not conducting of link of first link of this switching device and this switching device.
The present invention also provides a kind of automatic laser power control circuit, it accepts a luminous intensity feedback signal and an optical coupling signal of a photoinduction circuit, with the control one drive circuit, and then it is luminous to drive a laser diode, it is characterized in that, this automatic laser power control circuit comprises: a feedback amplifier, be coupled to this photoinduction circuit, to drive this laser diode luminous in order to accept this optical coupling signal, and accept this luminous intensity feedback signal, to adjust the luminous power of this laser diode emission; An and ON-OFF control circuit, have first link, second link, the 3rd link, the 4th link and an activation control end, this activation control end receives one first control signal, first link of this ON-OFF control circuit is coupled to one first power supply, second link of this ON-OFF control circuit is coupled to this feedback amplifier, the 4th link of this ON-OFF control circuit couples this drive circuit in a node, comes activation or this drive circuit of forbidden energy in order to the control of accepting one first control signal; When this first control signal forbidden energy, this ON-OFF control circuit makes this feedback amplifier be not attached to this drive circuit, and an equivalent damping is provided, make this first power supply be connected to this drive circuit, and this drive circuit does not provide electric current to this laser diode through this equivalence damping.
For above and other objects of the present invention, feature and advantage can be become apparent, preferred embodiment cited below particularly, and conjunction with figs. is described in detail below.
Description of drawings
Fig. 1 is the circuit diagram that concerns of the ON-OFF control circuit of common laser diode automatic laser power control circuit and whole laser diode drive system;
Fig. 2 is a kind of circuit diagram that is applied to the laser diode drive system of CD-ROM drive of a preferred embodiment of the present invention;
Fig. 3 A is when LDEN is activation, the equivalent circuit diagram of the ON-OFF control circuit of Fig. 2; And
Fig. 3 B is when LDEN is forbidden energy, the equivalent circuit diagram of the ON-OFF control circuit of Fig. 2.
Label declaration
106,108,121,201,211,213: resistance
181: variable resistor
105,107,221,222: electric capacity
131,231: inductance
141,241: laser diode
111: light sensitive diode
161,261,262: transistor
171, the 271:BJT transistor
281,282: transmission gate
151,301: feedback amplifier
302: common control circuit
303: common automatic laser power control circuit
304: drive circuit
305: the ON-OFF control circuit of preferred embodiment of the present invention
306: photoinduction circuit
307: the laser diode drive system
308: the automatic laser power control circuit of preferred embodiment of the present invention
Embodiment
Please refer to Fig. 2, Fig. 2 is a kind of circuit diagram that is applied to the laser diode drive system of CD-ROM drive of a preferred embodiment of the present invention.
Automatic laser power control circuit 308 of the present invention is made of feedback amplifier 301 and ON-OFF control circuit 305.Wherein, feedback amplifier 301 is coupled to ON-OFF control circuit 305 and photoinduction circuit 306, and 305 of ON-OFF control circuit couple drive circuit 304.Above-mentioned various circuit, driven laser diode 241 constitute whole laser diode drive system 307 with electric capacity 222.
The automatic laser power control circuit 308 of present embodiment uses the first power vd D3, for example: 3.3V, and accept the first control signal LDEN simultaneously and the second control signal LDENB controls as switch, the second control signal LDENB is the anti-phase of the first control signal LDEN, drive circuit 304 then uses second source VDD5, for example: 5.0V.
In the present embodiment, when the first control signal LDEN is high potential (when the second control letter is electronegative potential LDENB number), the optical coupling signal of this feedback amplifier 301 can be connected to this drive circuit, automatic laser power control circuit 308 activation drive circuits 304 just, and then driving laser diode.
When the first control LDEN signal electronegative potential (during the second control signal LDENB high potential), ON-OFF control circuit 305 will provide the equivalent resistance of an effective high impedance, make drive circuit 304 forbidden energy, can close laser diode 241 fully.
Wherein the ON-OFF control circuit 305 of automatic laser power control circuit 308 is made of 281,282,261,262 and 1 resistance 211 of 4 electronic switches.And the electronic switch 261 employing P type MOS transistor of this preferred embodiment, electronic switch 262 is to adopt N type MOS transistor, and 281,282 of electronic switches are the transmission gates that adopts two control ends.
Wherein, this ON-OFF control circuit 305 couples feedback amplifier 301, and drive circuit 304.And the power vd D3 of ON-OFF control circuit is 3.3 volts, and drive circuit power vd D5 is 5.0 volts.
In addition, the transmission gate (281,282) on this ON-OFF control circuit itself be with accept two opposite potential as control itself conducting (or claim open ON) with close (OFF).
Please also refer to Fig. 2 and Fig. 3 A, Fig. 3 A is when LDEN is activation, the equivalent circuit diagram of the ON-OFF control circuit of Fig. 2.When the first control signal LDEN high potential (Hi) (i.e. the second control signal LDENB electronegative potential (Low)), transmission gate 282 and P channel MOS transistor 261 are closed, transmission gate 281 and 262 conductings of N channel MOS transistor, this moment, the signal of feedback amplifier was connected to this drive circuit, on the X2 point, form a current potential, make and between the VDD5 of the second source source of X2 point and drive circuit, form a bias voltage, be enough to make BJT transistor 271 conductings (ON), laser diode 241 tool lasing fluorescence characteristics.
Please also refer to Fig. 2 and Fig. 3 B, Fig. 3 B is when LDEN is forbidden energy, the equivalent circuit diagram of the ON-OFF control circuit of Fig. 2.When the first control signal LDEN electronegative potential (Low) when the second control signal LDENB high potential (Hi) (also), 261 conductings of P channel MOS transistor, transmission gate 282 conductings and transmission gate 281 is closed with N channel MOS transistor 262.This moment on the Y2 point, have one with the almost equal current potential (3.3 volts) of power vd D3, pressure reduction according to the power vd D3 of the power vd D5 of drive circuit 304 and ON-OFF control circuit 305, get a proper resistor 211, according to minute platen press make on the X2 point form one with the approaching current potential of laser diode driver circuit 304 power vd D5, almost approaching when the emitter-base bandgap grading end and the base terminal current potential of P type BJT transistor 271, this P type BJT transistor 271 is in cut-off state.Therefore, the collector terminal of this P type BJT transistor 271 does not just have electric current and flows out, and laser diode 241 is closed (OFF).
Know that as the personnel that are familiar with above technology resistance 211 is a kind of of damping device, and 4 electronic switches 281,282,261,262 can integral body be considered as a kind of switching device, and not as limit.
Comprehensively above-mentioned, present embodiment utilizes two transmission gates, two transistors and a suitable resistance, constitute the ON-OFF control circuit of automatic laser power control circuit, make under the automatic laser power control circuit situation different with the drive circuit power supply, can close laser diode fully, reach the useful life that prolongs laser diode.
Though the present invention with preferred embodiment openly as above; so it is not to be used to limit the present invention, any those of ordinary skill in the art, without departing from the spirit and scope of the present invention; can do some equivalences and change and change, so protection scope of the present invention is as the criterion with claim.
Claims (19)
1, a kind of ON-OFF control circuit is applied to the automatic laser power control circuit in the laser diode drive system, and this ON-OFF control circuit is coupled to an one drive circuit and a feedback amplifier, it is characterized in that, comprising:
One first electronic switch has first link, second link and control end, and first link of this first electronic switch is coupled to this feedback amplifier;
One second electronic switch has first link, second link and control end, and first link of this second electronic switch is coupled to one first power supply;
One the 3rd electronic switch has first link, second link and control end, and second link of the 3rd electronic switch is coupled to this drive circuit;
One quadrielectron switch, have first link, second link and control end, second link of this first electronic switch, second link of this second electronic switch, first link of the 3rd electronic switch and first link of this quadrielectron switch are coupled in together; And
One resistance has first end and second end, and first end of this resistance is coupled to second link of this quadrielectron switch, and second end of this resistance is coupled to second link of the 3rd electronic switch;
Each control end of this first electronic switch, this second electronic switch, the 3rd electronic switch and this quadrielectron switch is coupled to one first control signal, when this first control signal activation, make this first electronic switch and the 3rd electronic switch conducting, and this second electronic switch and quadrielectron switch are closed, when this first control signal forbidden energy, make this second electronic switch and quadrielectron switch conduction, and this first electronic switch and the 3rd electronic switch are closed.
2, ON-OFF control circuit as claimed in claim 1 is characterized in that, this second electronic switch is a first transistor, and the 3rd electronic switch is a transistor seconds, and this first transistor is different with the kenel of this transistor seconds.
3, ON-OFF control circuit as claimed in claim 2 is characterized in that, this first transistor is a P type MOS transistor.
4, ON-OFF control circuit as claimed in claim 2 is characterized in that, this transistor seconds is a N type MOS transistor.
5, ON-OFF control circuit as claimed in claim 2, it is characterized in that, this first electronic switch is one first transmission gate, this quadrielectron switch is one second transmission gate, this first transmission gate and the defeated door of this second transmission are accepted the control of one second control signal, and this second control signal and this first control signal are anti-phase.
6, ON-OFF control circuit as claimed in claim 5 is characterized in that, when this first control signal is high potential, and this first transmission gate and this transistor seconds conducting, and this first transistor and this not conducting of second transmission gate; When this first control signal is electronegative potential, this first transistor and this second transmission gate conducting, this first transmission gate and this not conducting of transistor seconds.
7, ON-OFF control circuit as claimed in claim 1 is characterized in that, when this drive circuit was coupled to a second source, this first power values was less than this second source value.
8, ON-OFF control circuit as claimed in claim 7 is characterized in that, this first power supply is 3.3V, and second source is 5.0V, and then this resistance is 1M Ω.
9, a kind of ON-OFF control circuit is applied to the automatic laser power control circuit in the laser diode drive system, and this ON-OFF control circuit is coupled to an one drive circuit and a feedback amplifier, it is characterized in that, comprising:
One switching device, have first link, second link, the 3rd link, the 4th link and an activation control end, this activation control end receives one first control signal, first link of this switching device is coupled to one first power supply, second link of this switching device is coupled to this feedback amplifier, and the 4th link of this switching device couples this drive circuit in a node; And
One damping has first link and second link, and first link of this damping couples the 3rd link of this switching device, and second link of this damping is coupled to this node;
When this first control signal activation, make the 3rd link conducting of first link and this switching device of this switching device, and the 4th not conducting of link of second link of this switching device and this switching device, when this first control signal forbidden energy, make the 4th link conducting of second link and this switching device of this switching device, and the 3rd not conducting of link of first link of this switching device and this switching device.
10, ON-OFF control circuit as claimed in claim 9 is characterized in that, this switching device comprises:
One first electronic switch has first link, second link and a control end, and first link of this first electronic switch is electrically coupled to this feedback amplifier by second link of this switching device;
One second electronic switch has first link, second link and a control end, and first link of this second electronic switch is electrically coupled to this first power supply by first link of this switching device;
One the 3rd electronic switch has first link, second link and a control end, and second link of the 3rd electronic switch is electrically coupled to this drive circuit by the 4th link of this switching device; And
One quadrielectron switch, have first link, second link and a control end, second link of this quadrielectron switch is electrically coupled to this damping by the 3rd link of this switching device, and second link of this first electronic switch, second link of this second electronic switch, first link of the 3rd electronic switch and first link of this quadrielectron switch are coupled in together;
Each control end of this first electronic switch, this second electronic switch, the 3rd electronic switch and this quadrielectron switch couples this first control signal, when this first control signal activation, make this first electronic switch and the 3rd electronic switch conducting, and this second electronic switch and quadrielectron switch disconnect, when this first control signal forbidden energy, make this second electronic switch and quadrielectron switch conduction, and this first electronic switch and the disconnection of the 3rd electronic switch.
11, ON-OFF control circuit as claimed in claim 10, it is characterized in that, this first electronic switch is one first transmission gate, this quadrielectron switch is one second transmission gate, this first transmission gate and this second transmission gate are more accepted the control of one second control signal, and this second control signal and this first control signal are anti-phase.
12, ON-OFF control circuit as claimed in claim 9 is characterized in that, when this drive circuit was coupled to a second source, this first power supply was less than this second source.
13, a kind of automatic laser power control circuit, it accepts a luminous intensity feedback signal and an optical coupling signal of a photoinduction circuit, and with the control one drive circuit, and then it is luminous to drive a laser diode, it is characterized in that this automatic laser power control circuit comprises:
One feedback amplifier is coupled to this photoinduction circuit, and to drive this laser diode luminous in order to accept this optical coupling signal, and accept this luminous intensity feedback signal, to adjust the luminous power of this laser diode emission; And
One ON-OFF control circuit, have first link, second link, the 3rd link, the 4th link and an activation control end, this activation control end receives one first control signal, first link of this ON-OFF control circuit is coupled to one first power supply, second link of this ON-OFF control circuit is coupled to this feedback amplifier, the 4th link of this ON-OFF control circuit couples this drive circuit in a node, comes activation or this drive circuit of forbidden energy in order to the control of accepting one first control signal;
When this first control signal forbidden energy, this ON-OFF control circuit makes this feedback amplifier be not attached to this drive circuit, and an equivalent damping is provided, make this first power supply be connected to this drive circuit, and this drive circuit does not provide electric current to this laser diode through this equivalence damping.
14, automatic laser power control circuit as claimed in claim 13 is characterized in that, this ON-OFF control circuit comprises:
One first electronic switch has first link, second link and control end, and first link of this first electronic switch is electrically coupled to this feedback amplifier by second link of this ON-OFF control circuit;
One second electronic switch has first link, second link and control end, and first link of this second electronic switch is electrically coupled to this first power supply by first link of this ON-OFF control circuit;
One the 3rd electronic switch has first link, second link and control end, and second link of the 3rd electronic switch is electrically coupled to this drive circuit by the 4th link of this ON-OFF control circuit;
One quadrielectron switch, have first link, second link and control end, second link of this first electronic switch, second link of this second electronic switch, first link of the 3rd electronic switch and first link of this quadrielectron switch are coupled in together; And
One resistance has first end and second end, and first end of this resistance is coupled to second link of this quadrielectron switch, and second end of this resistance is coupled to second link of the 3rd electronic switch;
Each control end of this first electronic switch, this second electronic switch, the 3rd electronic switch and this quadrielectron switch is coupled to this first control signal, when this first control signal activation, make this first electronic switch and the 3rd electronic switch conducting, and this second electronic switch and quadrielectron switch disconnect, when this first control signal forbidden energy, make this second electronic switch and quadrielectron switch conduction, and this first electronic switch and the disconnection of the 3rd electronic switch.
15, automatic laser power control circuit as claimed in claim 14 is characterized in that, this second electronic switch is a first transistor, and the 3rd electronic switch is a transistor seconds, and this first transistor is different with the kenel of this transistor seconds.
16, automatic laser power control circuit as claimed in claim 15 is characterized in that, this first transistor is a P type MOS transistor, and this transistor seconds is a N type MOS transistor.
17, automatic laser power control circuit as claimed in claim 14, it is characterized in that, this first electronic switch is one first transmission gate, this quadrielectron switch is one second transmission gate, this first transmission gate and this second transmission gate are also accepted the control of one second control signal, and this second control signal and this first control signal are anti-phase.
18, automatic laser power control circuit as claimed in claim 17 is characterized in that, when this first control signal is high potential, and this first transmission gate and this transistor seconds conducting, and this first transistor and this not conducting of second transmission gate; When this first control signal is electronegative potential, this first transistor and this second transmission gate conducting, this first transmission gate and this not conducting of transistor seconds.
19, automatic laser power control circuit as claimed in claim 18 is characterized in that, when this drive circuit was coupled to a second source, this first power values was less than this second source value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021426457A CN1224145C (en) | 2002-09-18 | 2002-09-18 | Automatic laser power control circuit and its switch control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021426457A CN1224145C (en) | 2002-09-18 | 2002-09-18 | Automatic laser power control circuit and its switch control circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1404193A CN1404193A (en) | 2003-03-19 |
| CN1224145C true CN1224145C (en) | 2005-10-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021426457A Expired - Lifetime CN1224145C (en) | 2002-09-18 | 2002-09-18 | Automatic laser power control circuit and its switch control circuit |
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| CN (1) | CN1224145C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4520109B2 (en) * | 2003-05-26 | 2010-08-04 | パナソニック株式会社 | Laser power control circuit |
| CN1321487C (en) * | 2003-12-26 | 2007-06-13 | 亚洲光学股份有限公司 | High-power driving system |
| JP2005268338A (en) * | 2004-03-16 | 2005-09-29 | Matsushita Electric Ind Co Ltd | Laser drive circuit |
| CN100437766C (en) * | 2005-06-10 | 2008-11-26 | 上海乐金广电电子有限公司 | Optical-disc recording power supply control device and method therefor |
| EP2991244B1 (en) * | 2011-06-16 | 2018-01-24 | Huawei Technologies Co., Ltd. | Method and apparatus for controlling optical power |
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2002
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