Circuit and method for automatically measuring and calculating temperature control parameters of optical device

Abstract

The invention relates to the technical field of circuit control, in particular to a circuit and method for automatically measuring and calculating temperature control parameters of an optical device, and the circuit comprises a control unit, an oscilloscope, a thermosensitive sensing error compensation module and a TEC. The control unit is respectively connected with the thermosensitive sensing error compensation module, the oscilloscope and the TEC, and the thermosensitive sensing error compensation module is connected with the oscilloscope; the heat-sensitive sensor error compensation module comprises a temperature range setting unit, an error amplification unit, a compensation amplification unit and a PID (Proportion Integration Differentiation) module; the PID module comprises a proportion setting unit, an integral setting unit, a differential setting unit and a noise elimination unit. According to the method, the TEC control parameters are repeatedly and automatically measured through the program, the optimal control parameters are searched, and the tedious debugging process of repeated design and modification of designers is omitted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit control, in particular to a temperature control parameter automatic calculation circuit and method of an optical device. BACKGROUND

[0002] In the production and preparation process of an optical device, in order to stabilize the wavelength of a laser output, the laser needs to work in a constant temperature environment. A common solution in the industry is to add a TEC control component in the optical device. However, due to factors such as device size limitations, different optical devices require different types of TECs. Therefore, in the internal structure of the optical device, different TECs are often selected to balance the constant temperature requirement and energy efficiency. Whether it is an in-house evaluation test board of an optical device or a final product application at the module level, matching the best TEC control parameter is an essential part of circuit design. Suitable TEC control parameters can improve the stability and timeliness of TEC control, and at the same time, reduce the overall power consumption of the optical device. On the contrary, unsuitable TEC control parameters will result in inaccurate and unstable TEC temperature control, and even high power consumption and low efficiency.

[0003] Currently, the design of TEC control parameters is generally based on the experience of designers, which is influenced by personal subjective factors. Even if the same TEC control parameters are used, they cannot be applied to all types of TECs. Once the type of TEC changes or the use environment differs, the TEC control parameters need to be re-adjusted. Due to changes in hardware, production processes, and material preparation, the adjustment process will increase accordingly, which is not conducive to the smooth progress of product projects. SUMMARY

[0004] The purpose of the present application is to automatically calculate TEC control parameters through a program, find the best control parameters, and eliminate the tedious adjustment process of repeated design and modification by designers, thereby providing a temperature control parameter automatic calculation circuit and method of an optical device.

[0005] In order to achieve the above-mentioned application purpose, the embodiments of the present application provide the following technical solutions:

[0006] A temperature control parameter automatic calculation circuit of an optical device, comprising a control unit, an oscilloscope, a thermosensitive sensor error compensation module, and a TEC; the control unit is connected with the thermosensitive sensor error compensation module, the oscilloscope, and the TEC, and the thermosensitive sensor error compensation module is connected with the oscilloscope;

[0007] The heat-sensitive sensor error compensation module comprises a temperature range setting unit, an error amplification unit, a compensation amplification unit and a PID module; the PID module comprises a proportional setting unit, an integral setting unit, a differential setting unit and a noise elimination unit; the error amplification unit is connected with the temperature range setting unit, the proportional setting unit and the differential setting unit respectively, and the compensation amplification unit is connected with the proportional setting unit, the integral setting unit, the differential setting unit, the noise elimination unit and an oscilloscope respectively.

[0008] In the above scheme, the output end Control of the amplifier U2 is connected with the oscilloscope, which is used to display the voltage waveform output by the amplifier U2 after adjusting the resistance values and capacitance values in the PID module. The oscilloscope is connected with the control unit through USB, and the control unit controls the closing or opening of each switch in the PID module according to the voltage waveform collected by the oscilloscope, so as to realize the best parameter matching of the PID module and obtain the best TEC control parameters.

[0009] Further, the temperature range setting unit comprises a resistor R1, a resistor R2, a resistor R5 and a thermistor RTH, the error amplification unit comprises an amplifier U1, a resistor R3 and a resistor R4, the compensation amplification unit comprises an amplifier U2, the proportional setting unit comprises a resistor RI and a resistor RP, the integral setting unit comprises a capacitor CJ, the differential setting unit comprises a resistor RD and a capacitor CK, and the noise elimination unit comprises a capacitor CF.

[0010] The first end of the resistor R1 is connected with a reference voltage VREF, the second end of the resistor R1 is connected with the reverse input end of the amplifier U1 and the first end of the resistor R2 respectively, the second end of the resistor R2 is connected with the first end of the thermistor RTH, the second end of the thermistor RTH is grounded, and the first end of the resistor R5 is connected with the reverse input end of the amplifier U1; the forward input end of the amplifier U1 is connected with the first end of the resistor R3 and the first end of the resistor R4 respectively, the second end of the resistor R3 is connected with the reference voltage VREF, and the second end of the resistor R4 is grounded; the output end of the amplifier U1 is connected with the second end of the resistor R5, the first end of the resistor RI and the first end of the resistor RD respectively, the second end of the resistor RD is connected with the first end of the capacitor CK; the reverse input end of the amplifier U2 is connected with the second end of the resistor RI, the second end of the capacitor CK, the first end of the resistor RP and the first end of the capacitor CF respectively; the forward input end of the amplifier U2 is connected with the control unit and is used to receive the DAC_SET signal sent by the control unit; the second end of the resistor RP is connected with the first end of the capacitor CJ, and the output end of the amplifier U2 is connected with the second end of the capacitor CJ, the second end of the capacitor CF and the oscilloscope.

[0011] Further, the resistance RI, the resistance RP, the resistance RD, the capacitor CJ, the capacitor CK, and the capacitor CF are all combinations of components with multiple different resistance values or capacitance values, and each component is connected in series with a corresponding switch.

[0012] Further, the switch ST1 is connected in parallel with the capacitor CJ, and the switch ST2 is connected in parallel with the resistance RD.

[0013] A method for automatically calculating a temperature control parameter of an optical device, comprising the following steps:

[0014] Step 1: outputting a control signal DAC_SET to the compensation amplification unit through the control unit to set a temperature range of the TEC;

[0015] Step 2: setting resistance values and capacitance values of the PID module;

[0016] The step 2 specifically comprises the following steps:

[0017] Step 2-1: connecting the resistance RI, the resistance RP, and the capacitor CF to the circuit, and not connecting the capacitor CJ, the resistance RD, and the capacitor CK to the circuit to make the voltage oscillation displayed in the oscilloscope; adjusting the resistance values of the resistance RI and the resistance RP to make the voltage stable displayed in the oscilloscope, determining the resistance values of the resistance RI and the resistance RP, and determining the capacitance value of the capacitor CF;

[0018] Step 2-2: connecting the capacitor CJ to the circuit, and not connecting the resistance RD and the capacitor CK to the circuit to make the voltage oscillation displayed in the oscilloscope; adjusting the capacitance value of the capacitor CJ to make the voltage stable displayed in the oscilloscope, and determining the capacitance value of the capacitor CJ;

[0019] Step 2-3: connecting the capacitor CK to the circuit, and not connecting the resistance RD to the circuit to make the voltage oscillation displayed in the oscilloscope; connecting the resistance RD, adjusting the capacitance value of the capacitor CK and / or the resistance value of the resistance RD to make the voltage stable displayed in the oscilloscope, and determining the capacitance value of the capacitor CK and the resistance value of the resistance RD.

[0020] Further, the step 2-1 specifically comprises connecting the temperature range setting unit and the TEC to the circuit, outputting a voltage value corresponding to a required temperature of the TEC by the control signal DAC_SET, connecting the output end of the amplifier U2 to the oscilloscope, and connecting the oscilloscope to the control unit.

[0021] The control unit controls the switch ST1 to be closed, the switch ST2, the switch SD and the switch SK to be opened, the resistance value of the resistance RP is selected, then the resistance value of the resistance RI is randomly selected, the voltage waveform displayed on the oscilloscope is observed, the resistance value of the resistance RI is gradually reduced according to the first step, and the capacitance value of the capacitor CF is adjusted until the voltage oscillates, the resistance value of the resistance RP and the resistance RI, and the capacitance value of the capacitor CF are gradually increased according to the second step until the voltage is stable.

[0022] Further, the step 2-2 is specifically that the resistance RP, the resistance RI and the capacitor CF determined in the step 2-1 are connected to the circuit.

[0023] The control unit controls the switch ST1, the switch ST2, the switch SD and the switch SK to be opened, the capacitor with the minimum capacitance value in the capacitor CJ is selected to be connected to the circuit, the voltage waveform displayed on the oscilloscope is observed, the capacitance value of the capacitor CJ is gradually increased according to the third step until the voltage oscillates, the capacitance value of the capacitor CJ is gradually increased according to the fourth step until the voltage is stable, and the capacitance value of the capacitor CJ is obtained.

[0024] Further, the step 2-3 is specifically that the resistance RI and the resistance RP determined in the step 2-1 and the capacitor CJ determined in the step 2-2 are connected to the circuit.

[0025] The control unit controls the switch ST2 to be closed and the switch SD and the switch SF to be opened, the capacitor with a larger capacitance value than the capacitor CJ in the capacitor CK is selected to be connected to the circuit, the voltage waveform displayed on the oscilloscope is observed, the capacitance value of the capacitor CK is gradually reduced according to the fifth step, the switch SF is closed again, and the capacitance value of the capacitor CF is adjusted until the voltage oscillates, the switch ST2 is opened, the resistance with a larger resistance value than the resistance RI in the resistance RD is selected to be connected to the circuit, the capacitance value of the capacitor CK is reduced according to the fifth step, or the resistance value of the resistance RD is increased according to the sixth step until the voltage is stable, and the resistance value of the resistance RD, and the capacitance values of the capacitor CK and the capacitor CF are obtained.

[0026] Compared with the prior art, the beneficial effects of the present application are as follows: the change of the environment temperature of the optical device, the difference of the size of the optical device, the personal subjective reasons, the change of the TEC type and various factors can cause the problems of inaccuracy, instability, large power consumption and low efficiency in controlling the temperature of the TEC. In order to solve the problem, the resistance value and the capacitance value of the PID module are automatically calculated after the resistance value of the temperature range setting unit is set, so as to realize the best parameter matching of the PID module. When the optical device is applied to the product level, the user can quickly and accurately control the TEC to reach the required temperature according to the relationship between the voltage value of the control signal DAC_SET and the temperature value of the TEC, so as to meet the requirements of accuracy, stability, low power consumption and rapidness, and improve the experience of the user. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a block diagram of the circuit in an embodiment of the present invention;

[0029] Figure 2 This is a circuit diagram of the thermal sensing error compensation module according to an embodiment of the present invention;

[0030] Figure 3 A more detailed circuit diagram of the thermal sensing error compensation module according to an embodiment of the present invention is provided.

[0031] Figure 4 This is a connection diagram between the control unit and the oscilloscope in an embodiment of the present invention;

[0032] Figure 5(a) shows the voltage waveform when RP=100kΩ, RI=12.1kΩ, and CF=10nF in an embodiment of the present invention.

[0033] Figure 5(b) shows the voltage waveform when RP=100kΩ, RI=33.2kΩ, and CF=10nF in an embodiment of the present invention.

[0034] Figure 5(c) shows the voltage waveform when RP=100kΩ, RI=67.3kΩ, and CF=10nF in an embodiment of the present invention.

[0035] Figure 6(a) shows the voltage waveform when RP=100kΩ, RI=67.3kΩ, CJ=4.7μF, and CF=10nF in the embodiment of the present invention.

[0036] Figure 6(b) shows the voltage waveform of the embodiment of the present invention when RP=100kΩ, RI=67.3kΩ, CJ=10μF, and CF=10nF.

[0037] Figure 6(c) shows the voltage waveform of the embodiment of the present invention when RP=100kΩ, RI=67.3kΩ, CJ=20μF, and CF=10nF.

[0038] Figure 7(a) shows the voltage waveform of the embodiment of the present invention when RP=100kΩ, RI=67.3kΩ, CJ=20μF, RD=0Ω, and CK=10nF.

[0039] Figure 7(b) shows the voltage waveforms of the embodiment of the present invention when RP=100kΩ, RI=65.7kΩ, CJ=20μF, RD=365Ω, CK=10nF, and CF=10nF.

[0040] Figure 8 The voltage waveform diagram is shown in the embodiment of the present invention when RP=100kΩ, RI=65.7kΩ, CJ=20μF, RD=365Ω, CK=10nF, and CF=10nF. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0042] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance, or suggesting any such actual relationship or order between these entities or operations. Additionally, the terms "connected," "linked," etc., can refer to a direct connection between elements or an indirect connection via other elements.

[0043] Example 1:

[0044] This invention is achieved through the following technical solutions, such as... Figure 1 As shown, an automatic temperature control parameter calculation circuit for an optical device includes a control unit, an oscilloscope, a thermistor error compensation module, and a TEC (Thermal Control Unit). The control unit is connected to the thermistor error compensation module, the oscilloscope, and the TEC, respectively. The thermistor error compensation module is connected to the oscilloscope. Figure 2 The thermal sensor error compensation module includes a temperature range setting unit, an error amplification unit, a compensation amplification unit, and a PID module; the PID module includes a proportional setting unit, an integral setting unit, a derivative setting unit, and a noise cancellation unit.

[0045] The temperature range setting unit includes resistors R1, R2, R5, and a thermistor RTH, the error amplification unit includes an amplifier U1, resistors R3, and R4, the compensation amplification unit includes an amplifier U2, the proportional setting unit includes resistors RI and RP, the integral setting unit includes a capacitor CJ, the differential setting unit includes a resistor RD and a capacitor CK, and the noise elimination unit includes a capacitor CF. The first end of the resistor R1 is connected to a reference voltage VREF, the second end of the resistor R1 is connected to the inverting input terminal of the amplifier U1 and the first end of the resistor R2, the second end of the resistor R2 is connected to the first end of the thermistor RTH, the second end of the thermistor RTH is grounded, and the first end of the resistor R5 is connected to the inverting input terminal of the amplifier U1; the non-inverting input terminal of the amplifier U1 is connected to the first end of the resistor R3 and the first end of the resistor R4, the second end of the resistor R3 is connected to the reference voltage VREF, and the second end of the resistor R4 is grounded; the output terminal of the amplifier U1 is connected to the second end of the resistor R5, the first end of the resistor RI, and the first end of the resistor RD, the second end of the resistor RD is connected to the first end of the capacitor CK; the inverting input terminal of the amplifier U2 is connected to the second end of the resistor RI, the second end of the capacitor CK, the first end of the resistor RP, and the first end of the capacitor CF; the non-inverting input terminal of the amplifier U2 is connected to the control unit and is used to receive the DAC_SET signal sent by the control unit; the second end of the resistor RP is connected to the first end of the capacitor CJ, and the output terminal of the amplifier U2 is connected to the second end of the capacitor CJ, the second end of the capacitor CF, and the oscilloscope; and the oscilloscope is connected to the control unit.

[0046] Furthermore, the resistors RI, RP, RD, the capacitors CJ, CK, and CF are combinations of components with multiple different resistance values or capacitance values, and each component is connected in series with a corresponding switch. Figure 3As shown, resistor RI is connected to switch SI. Resistor RI includes multiple resistors with different resistance values, such as RI1, RI2, RI3, RI4, etc. Switch SI includes switches connected one-to-one with the resistors of RI, such as SI1, SI2, SI3, SI4, etc. Similarly, resistor RP is connected to switch SP. Resistor RP includes multiple resistors with different resistance values, such as RP1, RP2, RP3, RP4, etc. Switch SP includes switches connected one-to-one with the resistors of RP, such as SP1, SP2, SP3, SP4, etc. Capacitor CJ is connected to switch SJ. Capacitor CJ includes multiple capacitors with different capacitance values, such as CJ1, CJ2, CJ3, CJ4, etc. Switch SJ includes switches connected one-to-one with the capacitors of CJ, such as SJ1, SJ2, SJ3, SJ4, etc. The resistor RD is connected to a switch SD. Resistor RD includes multiple resistors with different resistance values, such as RD1, RD2, RD3, RD4, etc. Switch SD includes switches connected one-to-one with the resistors of RD, such as SD1, SD2, SD3, SD4, etc. The capacitor CK is connected to a switch SK. Capacitor CK includes multiple capacitors with different capacitance values, such as CK1, CK2, CK3, CK4, etc. Switch SK includes switches connected one-to-one with the capacitors of CK, such as SK1, SK2, SK3, SK4, etc. The capacitor CF is connected to a switch SF. Capacitor CF includes multiple capacitors with different capacitance values, such as CF1, CF2, CF3, CF4, etc. Switch SF includes switches connected one-to-one with the capacitors of CF, such as SF1, SF2, SF3, SF4, etc. It is easy to understand that this embodiment only lists four resistors or capacitors; however, in actual application scenarios, more resistors or capacitors can be set according to requirements.

[0047] Please continue reading Figure 3 This circuit also includes switches ST1 and ST2. Switch ST2 is connected in parallel with a series resistor RD and a switch SD, while switch ST1 is connected in parallel with a series capacitor CJ and a switch SJ. It should be noted that switches ST1 and ST2 are controlled to close or open by a control unit, which can be a relay or an analog switch.

[0048] like Figure 4 As shown, all switches are connected to the control unit. The control unit controls one or more switches in the switch group to close and the remaining switches to open via control signals. For example, when the control unit controls switch SI, it can close SI1 and open SI2, SI3, and SI4; or, when the control unit controls SI, it can close SI1 and SI3 and open SI2 and SI4. Other cases are similar and will not be elaborated further.

[0049] The output end Control of the amplifier U2 is connected with an oscilloscope, which is used to display the voltage waveform output by the amplifier U2 after adjusting the resistance value and capacitance value in the PID module. The oscilloscope is connected with the control unit through USB, and the control unit controls the closing or opening of each switch in the PID module according to the voltage waveform collected by the oscilloscope, so as to realize the best parameter matching of the PID module, thereby obtaining the best TEC control parameter.

[0050] Based on the above circuit, the application provides an automatic calculation method for temperature control parameters of an optical device, comprising the following steps:

[0051] Step 1: outputting a control signal DAC_SET to the compensation amplification unit through the control unit to set the temperature range of the TEC.

[0052] It is known that the characteristic of the thermistor RTH is that the resistance value is 10kΩ at the reference temperature . Assuming that the temperature range of the TEC needs to be set as , the lowest temperature , the medium temperature , and the highest temperature . Convert the units of the three temperature values from Celsius to Fahrenheit, and have

[0053] the lowest temperature ;

[0054] the medium temperature ;

[0055] the highest temperature ;

[0056] According to the resistance value-temperature relationship formula of the thermistor, the resistance values of the thermistor at the three temperatures are calculated as follows:

[0057]

[0058]

[0059]

[0060]

[0061] wherein, T R is the reference temperature (default ); R R is the resistance value of the thermistor at the reference temperature T R ; T is the current temperature; RTH is the resistance value of the thermistor at the current temperature T; β is the thermistor index (default 3950); RTH LOW is the resistance value of the thermistor at the current temperature T LOW(K) , TLOW(K) =283.15; RTH MID For the thermistor at the current temperature T MID(K) The resistance value under T MID(K) =298.15; RTH HIGH For the thermistor at the current temperature T HIGH(K) The resistance value under T HIGH(K) =313.15.

[0062] Next, select the resistance values ​​for resistors R1, R2, and R5:

[0063]

[0064]

[0065]

[0066] Since the relationship between the voltage value of the control signal DAC_SET and the temperature value of the TEC is already specified in the fabrication of the optical device, assuming that the temperature of the TEC needs to be controlled is... The control unit outputs a control signal DAC_SET corresponding to the voltage value. Then, by measuring the resistance of the thermistor and performing resistance conversion, the true temperature of the TEC can be determined. If the true temperature of the TEC is not the desired value... Then the voltage value of the control signal DAC_SET needs to be adjusted until the temperature of the TEC is [value missing]. However, as mentioned in the background section, various factors such as changes in the ambient temperature of the optical device, differences in the size of the optical device, subjective factors, and variations in the TEC type can lead to inaccuracies, instability, high power consumption, and low efficiency in controlling the TEC temperature. To address this issue, this solution sets the resistance and capacitance values ​​of the PID module after setting the resistance value of the temperature range setting unit. This achieves optimal parameter matching for the PID module. In product-level applications of optical devices, users can quickly and accurately control the TEC to reach the desired temperature based on the relationship between the voltage value of the control signal DAC_SET and the TEC temperature value, simultaneously meeting the requirements of accuracy, stability, low power consumption, and speed, thus improving the user experience.

[0067] Step 2: Set the resistance and capacitance values ​​of the PID module.

[0068] like Figure 3 As shown, step 2 specifically includes the following steps:

[0069] Step 2-1, connect resistance RI, resistance RP, and capacitor CF to the circuit, and do not connect capacitor CJ, resistance RD, and capacitor CK to the circuit, so that the voltage oscillation displayed in the oscilloscope; adjust the resistance values of resistance RI and resistance RP, so that the voltage displayed in the oscilloscope is stable, determine the resistance values of resistance RI and resistance RP, and determine the capacitance value of capacitor CF.

[0070] In detail, step 2-1 aims to measure the resistance values of resistance RI and resistance RP, and the capacitance value of capacitor CF. The temperature range setting unit and the TEC are connected to the circuit, the control signal DAC_SET outputs the voltage value corresponding to the required temperature of the TEC, the output end of the amplifier U2 is connected to the oscilloscope, and the oscilloscope is connected to the control unit. The control unit controls the switch ST1 to be closed (i.e. the capacitor CJ is short-circuited), and the switches ST2, SD, and SK are opened (i.e. the resistance RD and the capacitor CK are disconnected). The resistance value of resistance RP is selected according to experience, such as RP = 100kΩ, then the resistance value of resistance RI is randomly selected, such as RI = 100kΩ, the voltage waveform displayed on the oscilloscope is observed, the resistance value of resistance RI is gradually reduced according to the first step, and the capacitance value of capacitor CF is adjusted, until the voltage oscillation (oscillation refers to the voltage waveform being sinusoidal, and without high-frequency noise); the resistance value of resistance RI is gradually increased according to the second step, until the voltage is stable (stable refers to the voltage waveform tending to be direct current, and without high-frequency noise), and the resistance values of resistance RP and resistance RI, and the capacitance value of capacitor CF are obtained. The first step is at least 2 times of the second step.

[0071] It should be noted that since multiple resistors with different resistance values are arranged in resistance RI and resistance RP, the control unit can connect different resistance values of the resistors to the circuit by closing the switches corresponding to the resistors, so as to adjust the resistance values of resistance RI and resistance RP. The multiple resistors in resistance RI can also be controlled to be connected to the circuit at the same time, so as to finely adjust the step. The function of capacitor CF is to eliminate high-frequency noise, so when resistance RI and resistance RP are connected, capacitor CF is also connected, and by adjusting the value of capacitor CF, the voltage displayed on the oscilloscope does not have high-frequency noise. The specific resistance value of each resistor and the capacitance value of the capacitor are not limited by this embodiment, and can be selected and set according to actual conditions.

[0072] As an example: first, when the resistance value of the resistance RP is set to 100 kΩ, the resistance value of the resistance RI is reduced to 12.1 kΩ according to the first step, and the capacitance value of the capacitor CF is adjusted to 10 nF, the oscilloscope displays a sinusoidal waveform as shown in FIG. 5(a), i.e. the voltage oscillates and has no high-frequency noise; then, without changing the resistance value of the resistance RP, the resistance value of the resistance RI is increased to 33.2 kΩ according to the second step, the oscilloscope displays a voltage waveform as shown in FIG. 5(b), and the voltage gradually stabilizes from oscillation; finally, without changing the resistance value of the resistance RP, the resistance value of the resistance RI is continuously increased to 67.3 kΩ according to the second step, the oscilloscope displays a direct current waveform as shown in FIG. 5(c), i.e. the voltage is stable and has no high-frequency noise. Thus, the resistance value of the resistance RP is 100 kΩ, and the resistance value of the resistance RI is 67.3 kΩ. It should be noted that since the resistance RP and the resistance RI constitute the proportional setting unit, the voltage can be stabilized only when the ratio of the resistance RP and the resistance RI reaches a certain value, and therefore the resistance value of the resistance RP is fixed to 100 kΩ according to experience in this embodiment.

[0073] In step 2-2, the capacitor CJ is connected to the circuit, the resistance RD and the capacitor CK are not connected to the circuit, and the voltage in the oscilloscope oscillates. The capacitance value of the capacitor CJ is adjusted until the voltage in the oscilloscope is stable, and the capacitance value of the capacitor CJ is determined.

[0074] In detail, step 2-2 aims to measure the capacitance value of the capacitor CJ. The temperature range setting unit, the TEC, the resistance RP, the resistance RI and the capacitor CF determined in step 2-1 are connected to the circuit, and the voltage output by the control signal DAC SET remains unchanged. The control unit controls the switch ST1 to be open, and the switches ST2, SD and SK to be open (then the resistance RD and the capacitor CK are disconnected). The capacitor with the smallest or the smallest capacitance value in the capacitor CJ is selected to be connected to the circuit, and the voltage waveform displayed on the oscilloscope is observed. The capacitance value of the capacitor CJ is gradually increased according to the third step until the voltage oscillates. The capacitance value of the capacitor CJ is gradually increased according to the fourth step until the voltage is stable, and the capacitance value of the capacitor CJ is obtained. The fourth step is twice the third step.

[0075] As an example: first, when the capacitance value of the capacitor CJ is set to 4.7 μF, the oscilloscope displays a sinusoidal waveform as shown in FIG. 6(a), i.e. the voltage oscillates; then, the capacitance value of the capacitor CJ is increased to 10 μF according to the third step, the oscilloscope displays a voltage waveform as shown in FIG. 6(b), and the voltage gradually stabilizes from oscillation; finally, the capacitance value of the capacitor CJ is increased to 20 μF according to the fourth step, the oscilloscope displays a direct current waveform as shown in FIG. 6(c), i.e. the voltage is stable. Thus, the capacitance value of the capacitor CJ is 20 μF.

[0076] Step 2-3, connect capacitor CK to the circuit, do not connect resistor RD to the circuit, and make the voltage oscillate in the oscilloscope; connect resistor RD to the circuit, adjust the capacitance of capacitor CK and / or the resistance of resistor RD, and make the voltage stable in the oscilloscope, and determine the capacitance of capacitor CK and the resistance of resistor RD.

[0077] In detail, step 2-3 aims to measure the capacitance of capacitor CK and the resistance of resistor RD. Connect the temperature range setting unit, TEC, resistor RI and resistor RP determined in step 2-1, and capacitor CJ determined in step 2-2 to the circuit, and keep the voltage output by control signal DAC_SET unchanged. Control unit controls switch ST2 to be closed and switch SD to be disconnected (i.e. resistor RD is short-circuited), and controls switch SF to be disconnected (i.e. capacitor CF is disconnected). Select a capacitor in capacitor CK that is larger than capacitor CJ, and observe the voltage waveform displayed on the oscilloscope. Gradually reduce the capacitance of capacitor CK according to the fifth step, and then close switch SF again. Adjust the capacitance of capacitor CF until the voltage oscillates. Disconnect switch ST2, select a resistor in resistor RD that is larger than resistor RI, and connect it to the circuit. Reduce the capacitance of capacitor CK according to the fifth step, or increase the resistance of resistor RD according to the sixth step, until the voltage is stable. The resistance of resistor RD and the capacitances of capacitor CK and capacitor CF are obtained. Generally, resistor RD is larger than resistor RI, and capacitor CK is smaller than capacitor CJ.

[0078] As an example: first, when the capacitance of capacitor CK is reduced to 10 nF according to the fifth step, and resistor RD is short-circuited (i.e. the resistance of resistor RD is 0 Ω), since switch SF is disconnected at this time, capacitor CF is not connected to the circuit, and the oscilloscope displays a sine waveform with high-frequency noise as shown in FIG. 7(a). Close switch SF again, and adjust the capacitance of capacitor CF until the voltage oscillates and there is no high-frequency noise. Then, increase the resistance of resistor RD to 365 kΩ according to the sixth step, and the oscilloscope displays a voltage waveform as shown in FIG. 7(b). The voltage gradually stabilizes. Thus, the capacitance of capacitor CK is 10 nF, the capacitance of capacitor CF is 10 nF, and the resistance of resistor RD is 365 kΩ. It should be noted that the capacitance of capacitor CF is determined in step 2-1, and is verified again after connecting capacitor CK to determine whether the capacitance of capacitor CF can eliminate high-frequency noise.

[0079] Figure 8 After determining the resistance and capacitance of the PID module, the voltage waveform displayed on the oscilloscope when the circuit is started each time. Figure 8 The first waveform in FIG. 8 is the voltage value output by DAC_SET. When adjusting the voltage value output by DAC_SET, the circuit first oscillates and then stabilizes. If the ratio set by the ratio setting unit is not appropriate, the voltage fluctuation when starting will be large and the circuit cannot quickly enter a stable state. Figure 8 The second waveform in FIG. 8 is the voltage output by amplifier U1, Figure 8The third wave shape is the voltage outputted by the amplifier U2.

[0080] That is, the resistance RP and the resistance RI are proportional circuits, the ratio RP / RI is used for controlling the compensation amount of the PID module, the larger the ratio is, the larger the control offset is, the shorter the system stable time is, but the dynamic setting quality is poorer; the capacitor CJ is an integral circuit, the larger the capacity is, the more stable the system is, but the stable process is longer; the resistance RD and the capacitor CK are differential circuits, which are used for controlling the response speed of the system, the larger the value is, the faster the response speed is, but the stable process is slow, the smaller the value is, the slower the response speed is, but the stable process is faster; the capacitor CF is a noise elimination circuit, which is used for inhibiting the high frequency noise of the circuit, so that there is no high frequency noise when the voltage oscillates or stabilizes. In summary, through the method for measuring the suitable PID module parameters, the system stability will be improved.

[0081] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An automatic temperature control parameter calculation circuit for an optical device, characterized in that, It includes a control unit, an oscilloscope, a thermal sensor error compensation module, and a TEC; the control unit is connected to the thermal sensor error compensation module, the oscilloscope, and the TEC respectively, and the thermal sensor error compensation module is connected to the oscilloscope. The thermistor error compensation module includes a temperature range setting unit, an error amplification unit, a compensation amplification unit, and a PID module; the PID module includes a proportional setting unit, an integral setting unit, a derivative setting unit, and a noise cancellation unit; the error amplification unit is connected to the temperature range setting unit, the proportional setting unit, and the derivative setting unit respectively, and the compensation amplification unit is connected to the proportional setting unit, the integral setting unit, the derivative setting unit, the noise cancellation unit, and an oscilloscope respectively.

2. The automatic temperature control parameter calculation circuit for optical devices according to claim 1, characterized in that, The temperature range setting unit includes resistors R1, R2, and R5, and a thermistor RTH; the error amplification unit includes amplifier U1, resistors R3 and R4; the compensation amplification unit includes amplifier U2; the proportional setting unit includes resistors RI and RP; the integral setting unit includes capacitor CJ; the differential setting unit includes resistor RD and capacitor CK; and the noise cancellation unit includes capacitor CF. The first terminal of resistor R1 is connected to the reference voltage VREF. The second terminal of resistor R1 is connected to the inverting input terminal of amplifier U1 and the first terminal of resistor R2. The second terminal of resistor R2 is connected to the first terminal of the thermistor RTH, and the second terminal of the thermistor RTH is grounded. The first terminal of resistor R5 is connected to the inverting input terminal of amplifier U1. The non-inverting input terminal of amplifier U1 is connected to the first terminals of resistors R3 and R4. The second terminal of resistor R3 is connected to the reference voltage VREF, and the second terminal of resistor R4 is grounded. The output terminal of amplifier U1 is connected to the second terminals of resistor R5, RI, and RD. The second terminal of resistor RD is connected to the first terminal of capacitor CK. The inverting input terminal of amplifier U2 is connected to the second terminals of resistor RI, CK, RP, and CF. The non-inverting input terminal of amplifier U2 is connected to the control unit to receive the DAC_SET signal sent by the control unit. The second terminal of resistor RP is connected to the first terminal of capacitor CJ. The output terminal of amplifier U2 is connected to the second terminals of capacitor CJ, CF, and an oscilloscope.

3. The automatic temperature control parameter calculation circuit for optical devices according to claim 2, characterized in that, The resistors RI, RP, RD, capacitors CJ, CK, and CF are all combinations of components with different resistance or capacitance values, and each component is connected in series with a corresponding switch.

4. The automatic temperature control parameter calculation circuit for optical devices according to claim 2, characterized in that, It also includes switches ST1 and ST2. Switch ST1 is connected in parallel with capacitor CJ, and switch ST2 is connected in parallel with resistor RD.

5. A method for automatically calculating the temperature control parameters of an optical device, implemented based on the automatic temperature control parameter calculation circuit for an optical device as described in any one of claims 1-4, characterized in that, Includes the following steps: Step 1: The control unit outputs a control signal DAC_SET to the compensation amplifier unit to set the temperature range of the TEC; Step 2: Set the resistance and capacitance values ​​of the PID module; Step 2 specifically includes the following steps: Step 2-1: Connect resistors RI and RP, and capacitor CF to the circuit, and leave capacitors CJ, RD, and CK unconnected to the circuit, so that the voltage displayed on the oscilloscope oscillates; adjust the resistance values ​​of resistors RI and RP to stabilize the voltage displayed on the oscilloscope, and determine the resistance values ​​of resistors RI and RP, and the capacitance value of capacitor CF. Step 2-2: Connect capacitor CJ to the circuit, and do not connect resistor RD and capacitor CK to the circuit, so that the voltage displayed on the oscilloscope oscillates; adjust the capacitance value of capacitor CJ to stabilize the voltage displayed on the oscilloscope, and determine the capacitance value of capacitor CJ. Steps 2-3: Connect capacitor CK to the circuit, but not resistor RD, to make the voltage displayed on the oscilloscope oscillate; connect resistor RD, adjust the capacitance of capacitor CK and / or the resistance of resistor RD to stabilize the voltage displayed on the oscilloscope, and determine the capacitance of capacitor CK and the resistance of resistor RD.

6. The automatic calculation method for temperature control parameters of optical devices according to claim 5, characterized in that, Specifically, step 2-1 involves connecting the temperature range setting unit and the TEC access circuit, outputting the voltage value corresponding to the temperature required by the TEC using the control signal DAC_SET, connecting the output of amplifier U2 to an oscilloscope, and connecting the oscilloscope to the control unit. The control unit closes switch ST1 and opens switches ST2, SD, and SK. The resistance value of resistor RP is selected, and then the resistance value of resistor RI is randomly selected. The voltage waveform displayed on the oscilloscope is observed. Following the first step, the resistance value of resistor RI is gradually decreased, and the capacitance value of capacitor CF is adjusted until the voltage oscillates. Following the second step, the resistance value of resistor RI is gradually increased until the voltage stabilizes, thus obtaining the resistance values ​​of resistors RP and RI, and the capacitance value of capacitor CF. The first step is at least twice the value of the second step.

7. The automatic calculation method for temperature control parameters of optical devices according to claim 5, characterized in that, Specifically, step 2-2 involves connecting the resistor RP, resistor RI, and capacitor CF determined in step 2-1 into the circuit. The control unit controls switches ST1, ST2, SD, and SK to open; selects the capacitor with the smallest capacitance value among capacitors CJ and connects it to the circuit; observes the voltage waveform displayed on the oscilloscope; gradually increases the capacitance value of capacitor CJ according to the third step until the voltage oscillates; gradually increases the capacitance value of capacitor CJ according to the fourth step until the voltage stabilizes, thus obtaining the capacitance value of capacitor CJ; wherein, the fourth step is twice that of the third step.

8. The automatic calculation method for temperature control parameters of optical devices according to claim 5, characterized in that, Specifically, step 2-3 involves connecting the resistors RI and RP determined in step 2-1 and the capacitor CJ determined in step 2-2 into the circuit. The control unit closes switch ST2 and opens switches SD and SF. Select a capacitor CK larger than capacitor CJ and connect it to the circuit. Observe the voltage waveform displayed on the oscilloscope. Gradually decrease the capacitance of capacitor CK according to step five. Then close switch SF and adjust the capacitance of capacitor CF until the voltage oscillates. Open switch ST2 and select a resistor RD larger than resistor RI and connect it to the circuit. Decrease the capacitance of capacitor CK according to step five, or increase the resistance of resistor RD according to step six, until the voltage stabilizes. Obtain the resistance value of resistor RD, and the capacitance values ​​of capacitors CK and CF.

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