CN210926605U - Laser control circuit - Google Patents
Laser control circuit Download PDFInfo
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- CN210926605U CN210926605U CN201921783705.XU CN201921783705U CN210926605U CN 210926605 U CN210926605 U CN 210926605U CN 201921783705 U CN201921783705 U CN 201921783705U CN 210926605 U CN210926605 U CN 210926605U
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Abstract
The utility model discloses a laser control circuit, which comprises an automatic light power control circuit and an automatic temperature control circuit, wherein the automatic light power control circuit enables the power of the laser to be stabilized at a preset value; the automatic temperature control circuit stabilizes the working temperature of the laser. The utility model discloses has following technological effect: (1) the laser control circuit has the advantages of simple design, low cost and strong universality. (2) The automatic optical power control circuit of the laser control circuit enables the power of the laser to be stable, and the automatic temperature control circuit enables the working temperature to be stable, so that the laser control circuit ensures the output optical wavelength, the output optical power and the service life of the laser, the laser can work stably under various environments, the reliability is improved, and the service life of the laser is prolonged.
Description
Technical Field
The utility model relates to a laser instrument field especially relates to a laser instrument control circuit.
Background
In the field of optical fiber communication, a semiconductor laser is generally used as a light source, the emission wavelength of the semiconductor laser is closely related to the temperature of a tube core, the wavelength is lengthened due to the temperature rise, and for a 40GHz optical fiber delay line, because the wavelength interval between channels is already small, it is very important to keep the wavelength stable, so if the temperature of the tube core of the semiconductor laser is not controlled, the small temperature change can cause the whole system to be unusable. In addition, the semiconductor laser is a temperature-sensitive device, the stability of threshold current, output wavelength and output optical power of the semiconductor laser is very sensitive to temperature, and the working life of the semiconductor laser is closely related to the working temperature of the semiconductor laser. For the occasions with high reliability requirements, the temperature of the tube core of the semiconductor laser needs to be controlled to ensure the service life of the semiconductor laser, so that an automatic temperature control circuit needs to be added in a system to realize the temperature control of the tube core of the semiconductor laser.
At present, a semiconductor cooler (TEC) is mainly disposed inside the semiconductor laser to keep the internal temperature of the laser stable. However, the driving module of the conventional semiconductor refrigerator mainly adopts a pulse modulation mode and four MOSFET field effect transistors to drive the semiconductor refrigerator to work, and the frequency of pulse modulation directly affects the temperature precision of control and regulation by driving the semiconductor refrigerator to work, and when smaller temperature steady-state error is needed, the frequency of pulse modulation needs to be increased, which causes adverse effect on the working environment; MOSFET fets, which are switching functions, require faster turn-on speeds, resulting in increased device cost and susceptibility of the device to damage from overshoot.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the utility model provides a laser instrument control circuit makes laser instrument power stable, and operating temperature is stable, has guaranteed the output light wavelength, output optical power and the life of laser instrument.
In order to achieve the above purpose, the utility model adopts the following technical scheme: a laser control circuit, characterized by: the laser temperature control device comprises an automatic optical power control circuit and an automatic temperature control circuit, wherein the automatic optical power control circuit enables the power of the laser to be stabilized at a preset value, and the automatic temperature control circuit stabilizes the working temperature of the laser.
Preferably, the optical power control circuit comprises a current-to-voltage conversion module, a preset voltage module, a differential amplification module, a power amplification module and a laser, wherein the current-to-voltage conversion module and the preset voltage module are connected with the differential amplification module, the differential amplification module is connected with the power amplification module, the power amplification module is connected with the laser, and the laser is connected with the current-to-voltage conversion module.
Preferably, the laser is internally integrated with a photodiode for detecting the optical power of the laser.
Preferably, the preset voltage module employs a precision instrumentation amplifier INA 128.
Preferably, the differential amplification module employs a radio frequency follower OPA551 UA.
Preferably, the temperature control circuit comprises a thermistor voltage module, a reference voltage module, a comparison module, a thermoelectric refrigerator driving module and a thermoelectric refrigerator, wherein the thermistor voltage module and the reference voltage module are connected with the comparison module, the comparison module is connected with the thermoelectric refrigerator driving module, the thermoelectric refrigerator driving module is connected with the thermoelectric refrigerator, and the thermoelectric refrigerator is connected with the thermistor voltage module.
Preferably, the thermistor voltage module comprises a thermistor, and the thermistor and the thermoelectric cooler are integrated inside the laser.
Preferably, the comparison module adopts an operational amplifier chip MAX4478 ASD.
Preferably, the thermoelectric cooler driving module employs a semiconductor driving chip MAX 1968.
The utility model has the advantages as follows:
(1) the laser control circuit has the advantages of simple design, low cost and strong universality.
(2) The automatic optical power control circuit of the laser control circuit enables the power of the laser to be stable, and the automatic temperature control circuit enables the working temperature to be stable, so that the laser control circuit ensures the output optical wavelength, the output optical power and the service life of the laser, the laser can work stably under various environments, the reliability is improved, and the service life of the laser is prolonged.
(3) The automatic optical power control circuit utilizes a constant current source circuit consisting of a precision instrument amplifier INA128 and a radio frequency follower OPA551UA to adjust the driving current of the laser.
(4) The automatic temperature control circuit selects MAX1968, MAX1968 is a switch module driver for driving a semiconductor chilling plate, and has the advantages of high integration, low manufacturing cost, high efficiency and the like, wherein MAX1968 works in a single power supply and provides +/-3A bidirectional output current, so that nonlinearity of low-current working is eliminated, and the performance of the system can be improved when the set temperature is close to the ambient temperature.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic block diagram of an automatic optical power control circuit according to the present invention;
FIG. 2 is a schematic block diagram of the automatic temperature control circuit of the present invention;
fig. 3 is a diagram of a laser control circuit structure according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
A laser control circuit includes an automatic optical power control circuit and an automatic temperature control circuit.
As shown in fig. 1, the optical power control circuit includes a current-to-voltage conversion module 11, a preset voltage module 12, a differential amplification module 13, a power amplification module 14, and a laser 15, where the current-to-voltage conversion module 11 and the preset voltage module 12 are both connected to the differential amplification module 13, the differential amplification module 13 is connected to the power amplification module 14, the power amplification module 14 is connected to the laser 15, and the laser 15 is connected to the current-to-voltage conversion module 11.
The working mode is as follows: when the laser 15 is operating normally, it operates at a preset output power. When the optical power of the laser 15 changes, the output current of the photodiode inside the laser 15 changes, the output current of the photodiode is converted into a voltage through the current-to-voltage conversion module 11, the converted voltage and a preset voltage are input into the differential amplification module 13 for differential comparison, the driving current of the laser is adjusted, and the power is amplified to a power range in which the laser normally works through the power amplification module 14, and the laser 15 is driven to work. For example, when the output optical power of the laser 15 becomes high, the photocurrent detected by the photodiode becomes high, the current is converted into a voltage, the voltage converted correspondingly becomes high, the difference value with the preset voltage becomes small, so that the driving current becomes low, the driving power becomes low, and finally the power of the laser 15 is stabilized on the preset value.
As a preferred embodiment of the above embodiment, the laser 15 is internally integrated with a photodiode for detecting the optical power of the laser.
As shown in fig. 2, the automatic temperature control circuit includes a thermistor voltage module 21, a reference voltage module 22, a comparison module 23, a thermoelectric cooler driving module 24 and a thermoelectric cooler 25, wherein the thermistor voltage module 21 and the reference voltage module 22 are both connected to the comparison module 23, the comparison module 23 is connected to the thermoelectric cooler driving module 24, the thermoelectric cooler driving module 24 is connected to the thermoelectric cooler 25, and the thermoelectric cooler 25 is connected to the thermistor voltage module 21.
Preferably, the thermistor voltage module 21 includes a thermistor, and the thermistor and the thermoelectric cooler are integrated inside the laser.
As an illustrative example, the laser control circuit may be designed as shown in FIG. 3, including an automatic optical power control circuit and an automatic temperature control circuit, wherein the automatic optical power control circuit is as follows:
the 5-pin PD + of the laser is grounded; the 4-pin PD-of the laser is grounded through a resistor R10 and is also connected with the 3-pin Vin + of the chip U11; the 3-pin LD of the laser is connected with the anode of a diode D2, the first end of a resistor R16 and INA + of a chip U13, and the cathode of a diode D2 is grounded; the 2 pin TH2 of the laser is connected with the first end of the R20 of the resistor and is also connected with the 5 pin INB + of the chip U13; a pin 1 TH1 of the laser is connected with a capacitor C106, a pin 4V +, +5V input end of a chip U13, a capacitor C13 and a capacitor C11;
one end of the capacitor C13 is connected with the +5V input end, and the other end is grounded; one end of the capacitor C11 is connected with the +5V input end, and the other end of the capacitor C11 is grounded and connected with the first ends of the capacitors C12 and C14; the capacitors C12 and C14 are connected in parallel, and the second end of the capacitor C12 and C14 is connected with the-5V output end and the second end of the resistor R20;
the pin 2 Vin of the chip U11 is connected with the first end of the resistor R12, the first end of the capacitor C103 and the first end of the resistor R13, the second end of the resistor R12 is connected with the +5V input end, the first end of the resistor R13 is connected with the first end of the capacitor C103, the second end of the resistor R13 is connected with the second end of the capacitor C103, the second end of the resistor R13 is grounded and connected with the first end of the capacitor C104, and the second end of the capacitor C104 is connected with the pin 7V + of the chip U11; the 8-pin RG of the chip U11 is connected with the 1-pin RG of the chip U11 through a resistor R15, the 5-pin REF of the chip U11 is connected with the 1-pin OUTA and the 2-pin INA-of the U13, the 6-pin VOUT of the chip U11 is connected with the anode of a diode, the first end of a resistor R14 and the 3-pin in + of the U12, the cathode of the diode and the second end of the resistor R14 are grounded, and the 4-pin V-output-3V of the chip U11 is grounded and is also connected with the 4-pin V-of the chip U12 through a capacitor C102 and a capacitor C101;
the 2 pins IN-and 6 pins OUT of the chip U12 are both connected with the second end of the resistor R16, the 7 pins V + of the chip U12 output a power supply +5V, and the chip U12 is grounded through capacitors C39, C80 and C81;
among them, chip U11 can select precision instrumentation amplifier INA128UA, and its pin definition:
ref: a reference voltage output terminal;
RG: to be referenced to ground.
The chip U12 can select the radio frequency follower OPA551UA, and its pins define:
FLAG: a hot shut down indication pin.
The chip U13 may be an operational amplifier MAX4478ASD from manufacturer MAXIM.
The photocurrent detected by a photodiode used for detecting the optical power of the laser inside the laser is converted into voltage through a grounding resistor R10, then the voltage is input into a VIN + end of a precision instrument amplifier INA128 to be compared with a preset voltage value of the VIN-end, and then the voltage difference value is amplified from a VOUT end of the precision instrument amplifier INA128 through an IN + end of a radio frequency follower OPA551UA and then input into an operational amplifier MAX4478ASD to amplify the voltage to a range capable of driving the laser to normally work.
The circuit mainly utilizes a constant current source circuit consisting of a precision instrument amplifier INA128 and a radio frequency follower OPA551UA to regulate the driving current of the laser, the input ends of an INA128 chip are respectively a preset voltage and a voltage detected by a photodiode, the voltage input into the INA128 chip is equal to the detection voltage of the photodiode-the preset voltage, and the voltage at the position is a negative value because the laser is driven reversely. The radio frequency follower OPA551UA is added to increase the impedance at the input of the INA128 chip and to enable isolation of the load from the Ref pin. The voltage at the output terminal of the radio frequency follower OPA551UA is proportional to the reference current at the Ref pin of the INA128 chip, so that the voltage at the output terminal has a certain range value within the range of the reference current at the Ref pin, and finally the voltage is amplified to a range capable of driving the laser to normally work through the operational amplifier MAX4478 ASD.
The automatic temperature control circuit is as follows:
the 12-pin IND + of the operational amplifier MAX4478ASD is connected with the first end of the resistor R22, the second end of the resistor R22 is connected with GND _ TEC through the capacitor C29, is connected with the first end of the resistor R24, and is also connected with the 4-pin REF of the chip U21; the 1 pin Vdd of the chip U21 is connected with the +5V TEC and is connected with the first end of the capacitor C21, the 2 pin Vdd of the chip U21 is connected with the second end of the capacitor C21 and is connected with GND _ TEC, the 5 pin and the 7 pin of the chip U21 are connected with the first end of the capacitor C23 in parallel, the 3 pin CTL1 of the chip U21 is connected with the 14 pin of the operational amplifier MAX4478ASD, the 4 pin of the chip U21 is connected with GND _ TEC through the capacitor C29 and is connected with the second end of the resistor R22 and is connected with the first end of the resistor R24, the 6 pin, 8 pin and 10 pin of the chip U21 are connected with the first end of the inductor L21 in parallel, the 9 pin of the chip U21 is connected with GND _ TEC through the capacitor C22 and is connected with the 12 pin FREQ in parallel with the +5V _ TEC, the 11 pin and 12 pin of the chip U21 are connected with the second end of the capacitor C23 and the second end of the inductor V _ 4614, a first terminal of the capacitor C24, a pin 15 of the chip U21 and a first terminal of the resistor R26 are connected, a pin 16 of the chip U21 and a second terminal of the resistor R26, a second terminal of the inductor L22, a second terminal of the capacitor C25 and a second terminal of the capacitor C30 are connected, the first end of the capacitor C25 and the second end of the capacitor C24 are connected to GND _ TEC, the 17 pin, the 18 pin and the 20 pin of the chip U21 are connected in parallel to the first end of the capacitor C27, the first end of the capacitor C28 and +5v _ TEC, the 19 pin, the 21 pin and the 23 pin of the chip U21 are connected in parallel to the inductor L22, the 22 pin and the 24 pin of the chip U21 are connected in parallel to the second end of the capacitor C27, the second end of the capacitor C28, the first end of the capacitor C26 and GND _ TEC, the 25 pin of the chip U21 is connected to the second end of the capacitor C26, the 26 pin, the 27 pin and the 28 pin of the chip U21 are connected in parallel to the first end of the capacitor R25, the second end of the capacitor R24, and the second end of the capacitor R25.
Wherein chip U21 may select switch-mode driver MAX1968, whose pins define:
3-pin CTL 1: a thermoelectric refrigerator current control input;
4-pin REF: a reference voltage output terminal;
6-pin LX 2: an inductor connection terminal;
12-pin FREQ: a frequency switch selection terminal;
13-foot ITEC: a thermoelectric refrigerator current output;
14-pin OS 2: an output judgment end 2;
15-foot PS 1: outputting a judgment end 1;
16 feet CS: a current selection judgment terminal;
17 pin/SHDN: an on/off control input;
25-pin COMP: a current compensation terminal;
26 pins MAXIN: outputting the maximum current in the positive direction;
27-pin MAXIP: reversely outputting the maximum current;
28-pin MAXV: maximum output voltage
The three pins 26/27/28 in fig. 3 are mainly used to set the maximum current and the maximum voltage of cc output by the chip MAX1968, where the maximum current output in the forward and reverse directions is the 26 pin MAXIN and 27 pin MAXIP, respectively, and the maximum output voltage of 28 pin MAXV, which is calculated as:
MAXIN＝10(Rsense×Itecn) (1)
MAXIP＝10(Rsense×Itecp) (2)
|VOS1-VOS2|＝4×MAXV (3)
wherein MAXV-MAXIN-MAXIP-0.75V, Rsense100m Ω. The maximum current limit is 750 mA. Adjusting the value of the divider resistance, or adjusting RsenseThe current limit can be effectively adjusted, when the working temperature of the laser changes, the resistance value of the thermistor integrated in the laser changes along with the temperature, so that the voltage at two ends of the resistor changes, and the voltage is compared with a preset reference circuit to obtain a control signal for heating or refrigerating the TEC, so that the TEC built in the laser is driven to work normally, the temperature of the laser is stabilized, and the power is reduced.
The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. A laser control circuit comprises an automatic optical power control circuit and an automatic temperature control circuit, wherein the automatic optical power control circuit enables the power of a laser to be stabilized at a preset value, and the automatic temperature control circuit stabilizes the working temperature of the laser, and is characterized in that: the optical power control circuit comprises a current-to-voltage conversion module, a preset voltage module, a differential amplification module, a power amplification module and a laser, wherein the current-to-voltage conversion module and the preset voltage module are connected with the differential amplification module, the differential amplification module is connected with the power amplification module, the power amplification module is connected with the laser, and the laser is connected with the current-to-voltage conversion module.
2. A laser control circuit according to claim 1, wherein: and a photodiode for detecting the optical power of the laser is integrated in the laser.
3. A laser control circuit according to claim 1, wherein: the preset voltage module adopts an INA128 of a precision instrument.
4. A laser control circuit according to claim 1, wherein: the differential amplification module adopts a radio frequency follower OPA551 UA.
5. A laser control circuit according to claim 1, wherein: the temperature control circuit comprises a thermistor voltage module, a reference voltage module, a comparison module, a thermoelectric refrigerator driving module and a thermoelectric refrigerator; the thermistor voltage module and the reference voltage module are both connected with the comparison module; the comparison module is connected with the thermoelectric refrigerator driving module; the thermoelectric refrigerator driving module is connected with the thermoelectric refrigerator; the thermoelectric refrigerator is connected with the thermistor voltage module.
6. The laser control circuit of claim 5, wherein: the thermistor voltage module comprises a thermistor; the thermistor and the thermoelectric refrigerator are integrated in the laser.
7. The laser control circuit of claim 5, wherein: the comparison module adopts an operational amplifier MAX4478 ASD.
8. The laser control circuit of claim 5, wherein: the thermoelectric refrigerator driving module adopts a semiconductor driving chip MAX 1968.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921783705.XU CN210926605U (en) | 2019-10-18 | 2019-10-18 | Laser control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921783705.XU CN210926605U (en) | 2019-10-18 | 2019-10-18 | Laser control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210926605U true CN210926605U (en) | 2020-07-03 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921783705.XU Active CN210926605U (en) | 2019-10-18 | 2019-10-18 | Laser control circuit |
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|---|---|
| CN (1) | CN210926605U (en) |
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- 2019-10-18 CN CN201921783705.XU patent/CN210926605U/en active Active
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