CN111679705B - Low-cost digital high-precision wavelength control circuit and method - Google Patents
Low-cost digital high-precision wavelength control circuit and method Download PDFInfo
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- CN111679705B CN111679705B CN202010574679.0A CN202010574679A CN111679705B CN 111679705 B CN111679705 B CN 111679705B CN 202010574679 A CN202010574679 A CN 202010574679A CN 111679705 B CN111679705 B CN 111679705B
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- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
- G05D23/24—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor
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- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
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Abstract
The invention relates to a low-cost digital high-precision wavelength control circuit, which uses a bridge circuit and an amplifying circuit to perform PID calculation on a temperature feedback value of a thermistor according to a preset temperature value and the temperature feedback value, avoids the complexity caused by controlling the working temperature of a laser by using a hardware circuit, and improves the detection precision of the temperature of the laser by amplifying and linearly converting a voltage signal of the thermistor; after the working temperature of the laser is calculated and analyzed by the PID controller, a control or adjustment strategy is directly obtained, the temperature of the laser is heated or cooled, meanwhile, the two paths of 12-bit DAC signals are expanded into one path of 19-bit DAC signals, the voltage adjustment precision of the precision control circuit on the switching circuit is improved, the precision of the switching circuit on the temperature control of the laser is improved, the working temperature of the laser is controlled more accurately, and the accuracy of the wavelength control of the laser is improved.
Description
Technical Field
The invention relates to the technical field of measurement precision control, in particular to a low-cost digital high-precision wavelength control circuit and a method.
Background
The wavelength of the laser beam emitted from the laser changes due to the temperature of the environment, and the temperature of the laser needs to be detected in order to maintain the wavelength of the laser beam at a desired wavelength. As shown in fig. 4, when measuring the temperature of a laser or other devices, a thermistor is usually provided, and the temperature of the measured object can be known by measuring the resistance value or the voltage change of the thermistor.
However, when the temperature variation is large, for example, the variation is up to 150 degrees celsius, the voltage variation may be 2V, and when the temperature value is calculated by measuring the voltage variation, the precision is very low, so that the temperature measurement is not accurate, the purpose of precise temperature measurement cannot be achieved, and the temperature cannot be precisely controlled.
Disclosure of Invention
The present invention is directed to overcome the deficiencies of the prior art and to provide a digital high-precision wavelength control circuit and method with low cost.
In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:
the utility model provides a low-cost digital high accuracy wavelength control circuit, includes bridge circuit, amplifier circuit, PID controller, precision control circuit, switching circuit, wherein:
the bridge circuit is connected with the thermistor, outputs a differential voltage signal as a temperature feedback value to the amplifying circuit for the temperature value of the thermistor;
the amplifying circuit is used for amplifying and linearly converting the temperature feedback value output by the bridge circuit and outputting the temperature feedback voltage value after amplification and linear conversion to the PID controller;
the PID controller receives the temperature feedback value sent by the amplifying circuit, performs PID calculation on the temperature feedback value and a preset temperature set value, outputs a PID calculation result to the switching circuit, converts the PID calculation result into two 12-bit DAC signals and outputs the DAC signals to the precision control circuit; the PID calculation result is 16bit signed number;
the precision control circuit adjusts the working current of the switching circuit according to the DAC signal converted and output by the PID controller;
and the switching circuit switches the direction of the working current according to the sign of the PID calculation result output by the PID controller so as to switch the heating or cooling of the laser, and changes the magnitude of the working current according to the adjustment of the precision control circuit so as to adjust the power for heating or cooling the laser.
Furthermore, in order to better implement the present invention, the bridge circuit includes a resistor R32, a resistor R33, a resistor R34, and a resistor R35, one end of the resistor R32 and one end of the resistor R34 are commonly connected to a reference voltage Vref, one end of the resistor R33 is connected to the thermistor, the other end of the resistor R33 is connected to the other end of the resistor R32, the other end of the resistor R34 is connected to one end of the resistor R35, and the other end of the resistor R35 is grounded; the connection point of the resistor R32 and the resistor R33 and the connection point of the resistor R34 and the resistor R35 are respectively connected to the input end of the amplifying circuit.
Furthermore, in order to better implement the present invention, the amplifying circuit includes an operational amplifier U803 and a balance resistor R31, a forward input terminal of the operational amplifier U803 is connected to a connection point of a resistor R34 and a resistor R35, and a reverse input terminal of the operational amplifier U803 is connected to a connection point of a resistor R32 and a resistor R33; one end of the balance resistor R31 is connected with the reverse input end of the operational amplifier U803, and the other end of the balance resistor R31 is connected with the output end of the operational amplifier U803; the output end of the op amp U803 is connected to a PID controller.
Furthermore, in order to better implement the present invention, the precision control circuit includes a resistor R716, a resistor R715, a resistor R713, and a resistor R711, a second output terminal of the PID controller is connected to one end of the resistor R716, the other end of the resistor R716 is connected to one end of the resistor R715, the other end of the resistor R715 is grounded, and one end of the resistor R713 is connected to a connection point of the resistor R716 and the resistor R715;
the first output end of the PID controller is connected to the resistor R711, and the other end of the resistor R711 and the other end of the resistor R713 are connected with the switching circuit.
The PID controller inputs the PID calculation result output to the switching circuit through the TEC _ SW1 and the TEC _ SW2, and controls the current direction of the switching circuit consisting of the triode Q1, the triode Q2, the triode Q3 and the triode Q4 according to the sign of the PID calculation result.
A low-cost digital high-precision wavelength control method comprises the following steps:
the bridge circuit and the amplifying circuit amplify and linearly convert a temperature feedback value output by the connected thermistor and then output the temperature feedback value to the PID controller;
the PID controller performs PID calculation on the received temperature feedback value, outputs a PID calculation result to the switching circuit after calculation, converts the PID calculation result into a DAC signal and outputs the DAC signal to the precision control circuit;
the switching circuit switches the direction of the working current according to the sign of the PID calculation result output by the PID controller, so as to switch the heating or refrigeration of the laser;
the precision control circuit adjusts the working current of the switching circuit according to the DAC signal output by the PID controller, so that the switching circuit adjusts the power for heating or refrigerating the laser.
Further, in order to better implement the present invention, the step of amplifying and linearly converting the temperature feedback value output by the connected thermistor by the bridge circuit and the amplifying circuit, and outputting the amplified and linearly converted temperature feedback value to the PID controller includes:
the resistor R32 and the resistor R34 of the bridge circuit are connected with a reference voltage Vref, and the resistor R33 is connected with the thermistor RTHThe forward input end of an operational amplifier U803 of the amplifying circuit is connected to a connection point of a resistor R34 and a resistor R35, and the reverse input end of the operational amplifier U803 is connected to a connection point of a resistor R32 and a resistor R33;
bridge circuit pair thermistor RTHThe resistance value of the thermistor R is obtained by calculationTHResistance value of (d) versus temperature; according to the thermistor RTHThe amplifying circuit calculates the output voltage Vout1 of the operational amplifier U803 to obtain the thermistor RTHAnd the output voltage Vout1 of the amplifying circuit, and the thermistor RTHThe relationship between the temperature of (a) and the output voltage Vout1 of the amplifier circuit is sent to the PID controller for PID calculation.
Further, in order to better realize the present invention, the bridge circuit is coupled to the thermistor RTHThe resistance value of the thermistor R is obtained by calculationTHResistance value of (d) versus temperature; according to the thermistor RTHThe amplifying circuit calculates the output voltage Vout1 of the operational amplifier U803 to obtain the thermistor RTHThe relationship of the temperature of (a) and the output voltage Vout1 of the amplifying circuit, comprising:
calculating thermistor RTHResistance value versus temperature:
t in the formula (1) is a thermistor RTHHas a resistance value of RTHTemperature in Kelvin, beta is thermistor RTHTemperature coefficient of (T)RIs a thermistor RTHHas a resistance value of RRKelvin temperature of (i) in which R isR＝10000Ω，TR＝-273+25K；
Calculating the resistance parameter of the resistor R33:
r in the formula (2)LOWIs RTHAt the lowest operating temperature TLOWResistance value of RHIGHIs RTHAt the maximum operating temperature THIGHResistance value of RMIDIs RTHAt the average operating temperature TMIDA resistance value of (1), wherein
Calculating the resistance parameter of the resistor R32:
R32＝R33+RMID (3)
calculating the resistance parameter of a balance resistor R31 in the amplifying circuit:
obtaining reference voltage Vref according to the resistance values of the resistor R33, the resistor R32 and the resistor R31 calculated by the formulas (2), (3) and (4), and calculating the thermistor RTHTemperature of the amplifying circuit and output voltage Vout 1:
r in the formula (5)THThe resistance value of the thermistor at temperature T.
Furthermore, in order to better implement the present invention, the PID controller performs PID calculation on the received temperature feedback value, outputs the PID calculation result to the switching circuit after calculation, converts the PID calculation result into a DAC signal, and outputs the DAC signal to the precision control circuit, which includes:
the PID calculation result is 16bit signed number;
inputting the PID calculation result to the switching circuit through the TEC _ SW1 and the TEC _ SW2 of the switching circuit;
and converting the PID calculation result into two paths of DAC signals which are respectively a first DAC signal and a second DAC signal, sending the first DAC signal to the precision control circuit through the first output end, and sending the second DAC signal to the precision control circuit through the second output end.
Further, in order to better implement the present invention, the step of switching the laser to heat or cool by switching the direction of the operating current by the switching circuit according to the sign of the PID calculation result outputted by the PID controller includes:
when the sign of the PID calculation result output to the switching circuit by the PID controller is negative, the working current direction of the switching circuit is TEC-flow direction TEC +, so that the switching circuit heats the laser;
when the sign of the PID calculation result output by the PID controller to the switching circuit is positive, the working current direction of the switching circuit is TEC + flows to TEC-, so that the switching circuit refrigerates the laser.
Furthermore, in order to better implement the present invention, the step of adjusting the working current of the switching circuit by the precision control circuit according to the DAC signal output by the PID controller, so that the switching circuit adjusts the power for heating or cooling the laser includes:
the PID controller outputs a first DAC signal through a resistor R711 and outputs a second DAC signal through a resistor R716, the first DAC signal performs coarse adjustment on the voltage output to the switching circuit, the second DAC signal performs fine adjustment on the voltage output to the switching circuit, and the accuracy of the adjustment on the voltage by the second DAC signal is 128 times that of the first DAC signal;
the resistance value proportion relation among the resistor R716, the resistor R715, the resistor R713 and the resistor R711 is as follows:
the resolution ratio of the second DAC signal after being expanded by the resistors R716 and R715 is 7 bits higher than that of the first DAC signal after being expanded by the resistors R711 and R713, so that the first DAC signal with the resolution ratio of 12 bits and the second DAC signal with the resolution ratio of 12 bits are combined to form a DAC signal with the resolution ratio of 19 bits and output the DAC signal to the switching circuit, the voltage regulation precision of the switching circuit is improved, and the power regulation precision of heating or refrigerating the laser is improved by the switching circuit.
Compared with the prior art, the invention has the beneficial effects that:
according to the scheme, the bridge circuit and the amplifying circuit are used for amplifying and linearly converting the temperature feedback value of the thermistor to obtain the relationship between the temperature of the thermistor and the output voltage of the amplifying circuit, and the PID controller performs PID calculation according to the preset temperature value and the temperature feedback value subjected to linear conversion and amplification processing, so that the complexity caused by the fact that a hardware circuit is usually used for controlling the working temperature of the laser is avoided. Compared with the existing mode that the small voltage range corresponds to the large temperature range, the detection precision of the temperature of the laser is improved by amplifying and linearly converting the voltage signal of the thermistor, and after the PID controller calculates and analyzes the working temperature of the laser, a control and adjustment strategy is directly obtained to heat or refrigerate the temperature control of the laser; meanwhile, the two paths of 12-bit DAC signals are expanded into one path of 19-bit DAC signals, so that the voltage regulation precision of the precision control circuit on the switching circuit is further improved, the temperature control precision of the switching circuit on the laser is improved, the working temperature of the laser is controlled more accurately, and the wavelength control accuracy of the laser is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a schematic diagram of a bridge circuit and an amplifier circuit of the present invention;
FIG. 2 is a schematic diagram of a precision control circuit of the present invention;
FIG. 3 is a schematic diagram of a switching circuit of the present invention;
FIG. 4 is a circuit diagram of a prior art temperature sensing;
FIG. 5(a) is a graph showing the relationship between the resistance and the temperature of the thermistor in example 1;
fig. 5(b) is a graph showing the relationship between the temperature of the thermistor and the output voltage Vout1 of the amplifier circuit in example 1.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Also, in the description of the present invention, the terms "first", "second", and the like are used for distinguishing between descriptions and not necessarily for describing a relative importance or implying any actual relationship or order between such entities or operations.
Example 1:
the invention is realized by the following technical scheme, a low-cost digital high-precision wavelength control circuit comprises a bridge circuit, an amplifying circuit, a PID controller, a precision control circuit and a switching circuit, wherein the bridge circuit is connected with a thermistor, because the temperature of the thermistor is in a linear relation with the temperature of a laser, the bridge circuit is firstly required to be used for outputting a differential voltage signal to the temperature value of the thermistor as a temperature feedback value to be output to the amplifying circuit, the amplifying circuit converts the relation between the resistance value and the temperature of the thermistor into the relation between the temperature and the output voltage so as to obtain the relation between the temperature of the laser and the output voltage of the amplifying circuit, then the PID controller carries out PID calculation on the relation between the temperature and the voltage to analyze whether the current working temperature of the laser is the same as a preset temperature value, and the preset temperature value is the working temperature value required by the laser, and the calculated results are respectively sent to the precision control circuit and the switching circuit, the laser is controlled to be heated or cooled by controlling the current direction of the switching circuit, and the working current of the switching circuit is controlled by the precision control circuit, so that the power for heating or cooling the laser is adjusted.
The scheme uses the bridge circuit and the amplifying circuit to amplify and linearly transform the temperature feedback value of the thermistor to obtain the relationship between the temperature of the thermistor and the output voltage of the amplifying circuit, improves the detection and supervision on the working temperature of the laser, the PID controller performs PID calculation on the temperature of the thermistor and the output voltage of the amplifying circuit to avoid the complexity brought by the circuit when a hardware circuit is generally used for calculating the working temperature of the laser, the PID controller directly obtains a control and regulation strategy after calculating and analyzing the working temperature of the laser, the switching circuit changes the current direction according to the calculation result of the PID controller so as to switch the heating or refrigeration of the laser, and the precision control circuit further improves the precision of the voltage regulation of the switching circuit according to the strategy result output by the PID controller, compared with the existing mode that a small voltage range corresponds to a large temperature range, the precision of voltage regulation of the switching circuit is improved, so that the precision of temperature control of the laser is improved, the working temperature control of the laser is more accurate, and the accuracy of wavelength control of the laser is improved.
In detail:
as shown in fig. 1, the bridge circuit includes a resistor R32, a resistor R33, a resistor R34, and a resistor R35, one end of the resistor R32 and one end of the resistor R34 are commonly connected to a reference voltage Vref, one end of the resistor R33 is connected to a thermistor, the other end of the resistor R33 is connected to the other end of the resistor R32, the other end of the resistor R34 is connected to one end of the resistor R35, and the other end of the resistor R35 is grounded; the connection point of the resistor R32 and the resistor R33 and the connection point of the resistor R34 and the resistor R35 are respectively connected to the input end of the amplifying circuit. And the bridge circuit is simultaneously connected with the voltage of the thermistor and the reference voltage Vref, and the resistance value of the thermistor is calculated to obtain the relationship between the resistance value of the thermistor and the temperature.
As shown in fig. 1, the amplifying circuit includes an operational amplifier U803 and a balance resistor R31, a forward input terminal of the operational amplifier U803 is connected to a connection point of a resistor R34 and a resistor R35, and a reverse input terminal of the operational amplifier U803 is connected to a connection point of a resistor R32 and a resistor R33; one end of the feedback resistor R31 is connected with the reverse input end of the operational amplifier U803, and the other end of the resistor R31 is connected with the output end of the operational amplifier U803; the output end of the op amp U803 is connected to a PID controller. The amplifying circuit calculates the voltage Vout1 output by the operational amplifier U803 according to the relationship between the resistance value of the thermistor and the temperature sent by the bridge circuit, so as to obtain the relationship between the temperature of the thermistor and the output voltage Vout1 of the amplifying circuit, and sends the relationship to the PID controller.
And the PID controller receives the temperature feedback value sent by the amplifying circuit, analyzes the current working temperature of the laser after PID calculation, judges whether the working temperature of the laser is the same as a preset temperature value, outputs a sign of a PID calculation result to the switching circuit, and respectively sends a first DAC signal and a second DAC signal to the precision control circuit. Wherein the temperature feedback value sent by the amplifying circuit to the PID controller is a calculated relationship between the temperature of the thermistor and the output voltage Vout1 of the amplifying circuit.
As shown in fig. 2, the precision control circuit includes a resistor R716, a resistor R715, a resistor R713, and a resistor R711, a second output terminal of the PID controller is connected to one end of the resistor R716, the other end of the resistor R716 is connected to one end of the resistor R715, the other end of the resistor R715 is grounded, and one end of the resistor R713 is connected to a connection point of the resistor R716 and the resistor R715; the first output end of the PID controller is connected to the resistor R711, and the other end of the resistor R711 and the other end of the resistor R713 are connected with the output voltage control circuit.
And the switching circuit switches the working current direction according to the sign of the PID calculation result output by the PID controller. As shown in fig. 3, the PID calculation result outputted from the PID controller to the switching circuit is inputted through the TEC _ SW1 and the TEC _ SW2, and the current direction of the switching circuit composed of the transistor Q1, the transistor Q2, the transistor Q3, and the transistor Q4 is controlled according to the sign of the PID calculation result. When the sign of the PID calculation result is negative, the PID controller is indicated to calculate that the working temperature of the laser is lower than the required working temperature value, and the working current direction of the switching circuit is controlled to be TEC-flow direction TEC +, so that the switching circuit heats the laser; when the sign of the PID calculation result is positive, the working temperature of the laser calculated by the PID controller is higher than the required working temperature value, and the working current direction of the switching circuit is controlled to be TEC + flowing to TEC-, so that the switching circuit refrigerates the laser.
The first output end of the PID controller outputs a first DAC signal to the precision control circuit, the second output end of the PID controller outputs a second DAC signal to the precision control circuit, the resolution of the second DAC signal after being expanded by the resistors R716 and R715 is 7 bits higher than that of the first DAC signal after being expanded by the resistors R711 and R713, and therefore the first DAC signal with the resolution of 12 bits and the second DAC signal with the resolution of 12 bits are combined to form a DAC signal with the resolution of 19 bits and output to the switching circuit, the voltage regulation precision of the switching circuit is improved, and the power regulation precision of heating or refrigerating of the laser is improved by the switching circuit.
Based on the control circuit, the invention also provides a low-cost digital high-precision wavelength control method, which comprises the following steps:
step S1: the bridge circuit and the amplifying circuit amplify and linearly convert the temperature feedback value output by the connected thermistor and then output the temperature feedback value to the PID controller.
The resistor R32 and the resistor R34 of the bridge circuit are connected with a reference voltage Vref, and the resistor R33 is connected with the thermistor RTHThe forward input end of an operational amplifier U803 of the amplifying circuit is connected to a connection point of a resistor R34 and a resistor R35, and the reverse input end of the operational amplifier U803 is connected to a connection point of a resistor R32 and a resistor R33;
bridge circuit pair thermistor RTHThe resistance value of the thermistor R is obtained by calculationTHResistance value of (d) versus temperature; according to the thermistor RTHThe amplifying circuit calculates the output voltage Vout1 of the operational amplifier U803 to obtain the relationship between the temperature of the thermistor and the output voltage Vout1 of the amplifying circuit, and the thermistor R is usedTHThe relationship between the temperature of (a) and the output voltage Vout1 of the amplifier circuit is sent to the PID controller for PID calculation.
In detail, first, the thermistor R is calculatedTHResistance value versus temperature:
t in the formula (1) is a thermistor RTHHas a resistance value of RTHTemperature in Kelvin, beta is thermistor RTHTemperature coefficient of (T)RIs a thermistor RTHHas a resistance value of RRKelvin temperature of (i) in which R isR＝10000Ω，TR-273+ 25K. As shown in FIG. 5(a), a thermistor R was obtainedTHThe resistance value of (1) is shown in a graph with the relation of temperature.
Calculating the resistance parameter of the resistor R33:
r in the formula (2)LOWIs RTHAt the lowest operating temperature TLOWResistance value of RHIGHIs RTHAt the maximum operating temperature THIGHResistance value of time，RMIDIs RTHAt the average operating temperature TMIDA resistance value of (1), wherein
Calculating the resistance parameter of the resistor R32:
R32＝R33+RMID (3)
calculating the resistance parameter of a feedback resistor R31 in the amplifying circuit:
obtaining reference voltage Vref according to the resistance values of the resistor R33, the resistor R32 and the resistor R31 calculated by the formulas (2), (3) and (4), and calculating the thermistor RTHTemperature of the amplifying circuit and output voltage Vout 1:
r in the formula (5)THThe resistance value of the thermistor at temperature T. As shown in FIG. 5(b), a thermistor R was obtainedTHIs plotted against the output voltage Vout1 of the amplifier circuit.
In the step, the temperature monitoring feedback value is linearly converted and amplified in a mode of adding an amplifying circuit to an electric bridge, the relation between the resistance value and the temperature of the thermistor is converted into the relation between the temperature of the thermistor and the output voltage Vout1 of the amplifying circuit, and the relation between the temperature of the thermistor and the output voltage of the amplifying circuit is sent to the PID controller to calculate and analyze the working temperature of the laser.
Step S2: and the PID controller performs PID calculation on the received temperature feedback value, outputs a PID calculation result to the switching circuit after calculation, converts the PID calculation result into a DAC signal and outputs the DAC signal to the precision control circuit.
The PID calculation result is 16-bit signed number, and the PID calculation result is input to the switching circuit through the TEC _ SW1 and TEC _ SW2 of the switching circuit. And converting the PID calculation result into two paths of DAC signals which are respectively a first DAC signal and a second DAC signal, sending the first DAC signal to the precision control circuit through the first output end, and sending the second DAC signal to the precision control circuit through the second output end.
Step S3: the switching circuit switches the direction of the working current according to the sign of the PID calculation result output by the PID controller, so that the laser is switched between heating and cooling.
When the sign of the PID calculation result output to the switching circuit by the PID controller is negative, the working current direction of the switching circuit is TEC-flow direction TEC +, so that the switching circuit heats the laser; when the sign of the PID calculation result output by the PID controller to the switching circuit is positive, the working current direction of the switching circuit is TEC + flows to TEC-, so that the switching circuit refrigerates the laser.
Step S4: the precision control circuit adjusts the working current of the switching circuit according to the DAC signal output by the PID controller, so that the switching circuit adjusts the power for heating or refrigerating the laser.
The PID controller outputs a first DAC signal through a resistor R711 and outputs a second DAC signal through a resistor R716, the first DAC signal performs coarse adjustment on the voltage output to the switching circuit, the second DAC signal performs fine adjustment on the voltage output to the switching circuit, and the accuracy of the adjustment on the voltage by the second DAC signal is 128 times that of the first DAC signal;
the resistance value proportion relation among the resistor R716, the resistor R715, the resistor R713 and the resistor R711 is as follows:
the resolution ratio of the second DAC signal after being expanded by the resistors R716 and R715 is 7 bits higher than that of the first DAC signal after being expanded by the resistors R711 and R713, so that the first DAC signal with the resolution ratio of 12 bits and the second DAC signal with the resolution ratio of 12 bits are combined to form a DAC signal with the resolution ratio of 19 bits and output the DAC signal to the switching circuit, the voltage regulation precision of the switching circuit is improved, and the power regulation precision of heating or refrigerating the laser is improved by the switching circuit.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily change or replace the present invention within the technical scope of the present invention, and the present invention shall be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (7)
1. A low-cost digital high-precision wavelength control circuit is characterized in that: including bridge circuit, amplifier circuit, PID controller, precision control circuit, switching circuit, wherein:
the bridge circuit is connected with the thermistor, outputs a differential voltage signal as a temperature feedback value to the amplifying circuit for the temperature value of the thermistor;
the amplifying circuit is used for amplifying and linearly converting the temperature feedback value output by the bridge circuit and outputting the temperature feedback voltage value after amplification and linear conversion to the PID controller;
the PID controller receives the temperature feedback value sent by the amplifying circuit, performs PID calculation on the temperature feedback value and a preset temperature set value, outputs a PID calculation result to the switching circuit, converts the PID calculation result into two 12-bit DAC signals and outputs the DAC signals to the precision control circuit; the PID calculation result is 16bit signed number;
the precision control circuit adjusts the working current of the switching circuit according to the DAC signal converted and output by the PID controller;
the switching circuit switches the direction of the working current according to the sign of the PID calculation result output by the PID controller so as to switch the heating or refrigeration of the laser, and changes the magnitude of the working current according to the adjustment of the precision control circuit so as to adjust the power for heating or refrigeration of the laser;
the precision control circuit comprises a resistor R716, a resistor R715, a resistor R713 and a resistor R711, wherein a second output end of the PID controller is connected to one end of the resistor R716, the other end of the resistor R716 is connected with one end of the resistor R715, the other end of the resistor R715 is grounded, and one end of the resistor R713 is connected to a connection point of the resistor R716 and the resistor R715; a first output end of the PID controller is connected to the resistor R711, and the other end of the resistor R711 and the other end of the resistor R713 are connected with the switching circuit;
the PID controller outputs a first DAC signal through a resistor R711 and outputs a second DAC signal through a resistor R716, the first DAC signal performs coarse adjustment on the voltage output to the switching circuit, the second DAC signal performs fine adjustment on the voltage output to the switching circuit, and the accuracy of the adjustment on the voltage by the second DAC signal is 128 times that of the first DAC signal;
the resistance value proportion relation among the resistor R716, the resistor R715, the resistor R713 and the resistor R711 is as follows:
the resolution ratio of the second DAC signal after being expanded by the resistors R716 and R715 is 7 bits higher than that of the first DAC signal after being expanded by the resistors R711 and R713, so that the first DAC signal with the resolution ratio of 12 bits and the second DAC signal with the resolution ratio of 12 bits are combined to form a DAC signal with the resolution ratio of 19 bits and output the DAC signal to the switching circuit, the voltage regulation precision of the switching circuit is improved, and the power regulation precision of heating or refrigerating the laser is improved by the switching circuit.
2. A low cost digital high precision wavelength control circuit according to claim 1, wherein:
the bridge circuit comprises a resistor R32, a resistor R33, a resistor R34 and a resistor R35, wherein one end of the resistor R32 and one end of the resistor R34 are commonly connected with a reference voltage Vref, one end of the resistor R33 is connected with a thermistor, the other end of the resistor R33 is connected with the other end of the resistor R32, the other end of the resistor R34 is connected with one end of the resistor R35, and the other end of the resistor R35 is grounded;
the connection point of the resistor R32 and the resistor R33 and the connection point of the resistor R34 and the resistor R35 are respectively connected to the input end of the amplifying circuit.
3. A low cost digital high precision wavelength control circuit according to claim 2, characterized in that:
the amplifying circuit comprises an operational amplifier U803 and a balance resistor R31, wherein the forward input end of the operational amplifier U803 is connected to the connection point of a resistor R34 and a resistor R35, and the reverse input end of the operational amplifier U803 is connected to the connection point of a resistor R32 and a resistor R33; one end of the balance resistor R31 is connected with the reverse input end of the operational amplifier U803, and the other end of the balance resistor R31 is connected with the output end of the operational amplifier U803; the output end of the op amp U803 is connected to a PID controller.
4. A control method of a low-cost digital high-precision wavelength control circuit according to any one of claims 1 to 3, characterized in that: the method comprises the following steps:
the bridge circuit and the amplifying circuit amplify and linearly convert a temperature feedback value output by the connected thermistor and then output the temperature feedback value to the PID controller;
the PID controller performs PID calculation on the received temperature feedback value, outputs a PID calculation result to the switching circuit after calculation, converts the PID calculation result into a DAC signal and outputs the DAC signal to the precision control circuit;
the switching circuit switches the direction of the working current according to the sign of the PID calculation result output by the PID controller, so as to switch the heating or refrigeration of the laser;
the precision control circuit adjusts the working current of the switching circuit according to the DAC signal output by the PID controller, so that the switching circuit adjusts the power for heating or refrigerating the laser;
the PID controller performs PID calculation on the received temperature feedback value, outputs a PID calculation result to the switching circuit after calculation, converts the PID calculation result into a DAC signal and outputs the DAC signal to the precision control circuit, and the method comprises the following steps:
the PID calculation result is 16bit signed number;
inputting the PID calculation result to the switching circuit through the TEC _ SW1 and the TEC _ SW2 of the switching circuit;
converting the PID calculation result into two paths of DAC signals which are a first DAC signal and a second DAC signal respectively, sending the first DAC signal to the precision control circuit through a first output end, and sending the second DAC signal to the precision control circuit through a second output end;
the precision control circuit adjusts the working current of the switching circuit according to the DAC signal output by the PID controller, so that the switching circuit adjusts the power for heating or refrigerating the laser, and the method comprises the following steps:
the PID controller outputs a first DAC signal through a resistor R711 and outputs a second DAC signal through a resistor R716, the first DAC signal performs coarse adjustment on the voltage output to the switching circuit, the second DAC signal performs fine adjustment on the voltage output to the switching circuit, and the accuracy of the adjustment on the voltage by the second DAC signal is 128 times that of the first DAC signal;
the resistance value proportion relation among the resistor R716, the resistor R715, the resistor R713 and the resistor R711 is as follows:
the resolution ratio of the second DAC signal after being expanded by the resistors R716 and R715 is 7 bits higher than that of the first DAC signal after being expanded by the resistors R711 and R713, so that the first DAC signal with the resolution ratio of 12 bits and the second DAC signal with the resolution ratio of 12 bits are combined to form a DAC signal with the resolution ratio of 19 bits and output the DAC signal to the switching circuit, the voltage regulation precision of the switching circuit is improved, and the power regulation precision of heating or refrigerating the laser is improved by the switching circuit.
5. The control method according to claim 4, characterized in that: the bridge circuit and the amplifying circuit amplify and linearly convert the temperature feedback value output by the accessed thermistor and then output the temperature feedback value to the PID controller, and the method comprises the following steps:
the resistor R32 and the resistor R34 of the bridge circuit are connected with a reference voltage Vref, and the resistor R33 is connected with the thermistor RTHThe forward input end of an operational amplifier U803 of the amplifying circuit is connected to a connection point of a resistor R34 and a resistor R35, and the reverse input end of the operational amplifier U803 is connected to a connection point of a resistor R32 and a resistor R33;
bridge circuit pair thermistor RTHThe resistance value of the thermistor R is obtained by calculationTHResistance value of (d) versus temperature; according to the thermistor RTHThe amplifying circuit calculates the output voltage Vout1 of the operational amplifier U803 to obtain the thermistor RTHAnd the output voltage Vout1 of the amplifying circuit, and the thermistor RTHThe relationship between the temperature of (a) and the output voltage Vout1 of the amplifier circuit is sent to the PID controller for PID calculation.
6. The control method according to claim 5, characterized in that: the bridge circuit is used for the thermistor RTHThe resistance value of the thermistor R is obtained by calculationTHResistance value of (d) versus temperature; according to the thermistor RTHThe amplifying circuit calculates the output voltage Vout1 of the operational amplifier U803 to obtain the thermistor RTHThe relationship of the temperature of (a) and the output voltage Vout1 of the amplifying circuit, comprising:
calculating thermistor RTHResistance value versus temperature:
t in the formula (1) is a thermistor RTHHas a resistance value of
Temperature in Kelvin, beta is thermistor RTHThe temperature coefficient of (a) is,
is a thermistor RTHHas a resistance value of
A Kelvin temperature of (i) wherein
=10000Ω，
=-273+25K；
Calculating the resistance parameter of the resistor R33:
in the formula (2)
Is composed of
At the lowest working temperature
The resistance value of the time is equal to or less than,
is composed of
At maximum operating temperature
The resistance value of the time is equal to or less than,
is composed of
At the average operating temperature
A resistance value of (1), wherein
；
Calculating the resistance parameter of the resistor R32:
calculating the resistance parameter of a balance resistor R31 in the amplifying circuit:
obtaining reference voltage Vref according to the resistance values of the resistor R33, the resistor R32 and the resistor R31 calculated by the formulas (2), (3) and (4), and calculating the thermistor RTHTemperature of the amplifying circuit and output voltage Vout 1:
in the formula (5)
The resistance value of the thermistor at temperature T.
7. The control method according to claim 4, characterized in that: the switching circuit switches the direction of the working current according to the sign of the PID calculation result output by the PID controller, thereby switching the heating or refrigeration of the laser, comprising the following steps:
when the sign of the PID calculation result output to the switching circuit by the PID controller is negative, the working current direction of the switching circuit is TEC-flow direction TEC +, so that the switching circuit heats the laser;
when the sign of the PID calculation result output by the PID controller to the switching circuit is positive, the working current direction of the switching circuit is TEC + flows to TEC-, so that the switching circuit refrigerates the laser.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201576004U (en) * | 2009-12-18 | 2010-09-08 | 北京华航航宇科技有限公司 | High-precision self-compensation digital acceleration sensor |
| CN102589215A (en) * | 2012-02-02 | 2012-07-18 | 索尔思光电（成都）有限公司 | Automatic temperature control circuit |
| CN105843282A (en) * | 2016-03-23 | 2016-08-10 | 武汉光迅科技股份有限公司 | Temperature control device and temperature control method based on FPGA for optical amplifier |
| CN110647185A (en) * | 2019-09-24 | 2020-01-03 | 山东大学 | High-precision temperature measuring and controlling circuit |
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| CN100472900C (en) * | 2006-03-31 | 2009-03-25 | 中兴通讯股份有限公司 | Wavelength control circuit for tunable laser |
| US20150377526A1 (en) * | 2014-06-27 | 2015-12-31 | Lumentum Operations Llc | Thermoelectric cooler (tec) circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN201576004U (en) * | 2009-12-18 | 2010-09-08 | 北京华航航宇科技有限公司 | High-precision self-compensation digital acceleration sensor |
| CN102589215A (en) * | 2012-02-02 | 2012-07-18 | 索尔思光电（成都）有限公司 | Automatic temperature control circuit |
| CN105843282A (en) * | 2016-03-23 | 2016-08-10 | 武汉光迅科技股份有限公司 | Temperature control device and temperature control method based on FPGA for optical amplifier |
| CN110647185A (en) * | 2019-09-24 | 2020-01-03 | 山东大学 | High-precision temperature measuring and controlling circuit |
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