High-precision bias voltage adjusting system for optical module

Abstract

The application relates to a high-precision bias voltage adjusting system of an optical module, and belongs to the technical field of optical module testing.The system comprises an upper computer, a microcontroller, a power module and a feedback voltage adjusting circuit; the input end of the microcontroller collects the output voltage of the power module through an ADC; the output end of the microcontroller outputs an analog voltage to the feedback voltage adjusting circuit through a connected DAC; the feedback voltage adjusting circuit is connected with the power module and dynamically adjusts the output voltage of the power module based on the analog voltage; wherein, the microcontroller eliminates inherent hardware errors during system initialization, and in the process of adjusting and testing the bias voltage, an adaptive PID adjusting strategy is adopted to eliminate static errors, so that the error between the target bias voltage and the current output voltage of the power module is within a specified precision range.The application solves the technical problems of insufficient bias voltage adjusting precision, lack of adaptive capacity, no systematic protection and low testing efficiency in the existing bias voltage testing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical module testing, and in particular to an optical module high-precision bias voltage adjustment system. BACKGROUND

[0002] An optical module is a core device of an optical communication network, and its performance and reliability are crucial. In the production and quality inspection links, the optical module needs to be tested for voltage bias, that is, a positive or negative deviation is applied near the rated working voltage to test its working stability and fault tolerance under voltage fluctuation.

[0003] At present, the traditional voltage bias test mostly adopts a scheme of fixed resistance network combined with open-loop current control, which has the following main defects:

[0004] Low output precision: due to the open-loop control mode and the inherent error of components, the output voltage precision can usually only reach the order of tens of millivolts, which is difficult to meet the millivolt-level high-precision test requirement.

[0005] Insufficient stability: due to the lack of real-time voltage feedback mechanism, it is difficult to effectively suppress the voltage fluctuation caused by load changes or environmental interference, affecting the test consistency.

[0006] Low degree of intelligence: the system cannot real-time perceive the output state, cannot adaptively adjust the control parameters according to the actual test conditions, and lacks intelligent adjustment capability.

[0007] Reliability is questionable: it is difficult to realize the overvoltage and undervoltage protection functions at the software level, which poses a potential risk to high-value optical modules.

[0008] Low test efficiency: the existing system only supports manual single-point voltage setting, cannot automatically execute complex bias test procedures containing multiple voltage nodes, and relies on manual operation and recording, which is prone to errors and low in efficiency.

[0009] Therefore, in view of the problems of insufficient precision, poor stability, low degree of intelligence, and weak reliability in the prior art, the technical personnel in the field urgently need a voltage bias test scheme that can realize high-precision, adaptive adjustment, and has perfect protection function. SUMMARY

[0010] (I) Technical problems to be solved

[0011] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present application provides an optical module high-precision bias voltage adjustment system, which aims to solve the technical problems of insufficient bias voltage adjustment precision, lack of adaptive ability, no systematic protection, and low test efficiency in the existing bias voltage test.

[0012] (II) Technical scheme

[0013] In order to achieve the above object, the main technical scheme adopted by the present application comprises:

[0014] The embodiment of the present application provides a high-precision polarization voltage adjusting system for an optical module, comprising: an upper computer, a microcontroller connected to the upper computer, a power module connected to a to-be-tested optical module, and a feedback voltage adjusting circuit for adjusting the output voltage of the power module;

[0015] The input end of the microcontroller collects the output voltage of the power module through an ADC, and the ADC is arranged at the output end of the power module;

[0016] The output end of the microcontroller outputs an analog voltage to the adjusting end of the feedback voltage adjusting circuit through the connected DAC;

[0017] The first end of the feedback voltage adjusting circuit is connected to the output end of the power module, the second end is connected to the feedback end of the power module, and the third end is grounded, and the feedback voltage adjusting circuit dynamically adjusts the output voltage of the power module based on the analog voltage, so that the power module outputs a target polarization voltage;

[0018] In the initialization of the polarization voltage adjusting system, the microcontroller eliminates the inherent error of hardware based on the information of the upper computer and the data collected by the ADC, and in the adjustment test process of the polarization voltage, the adaptive PID adjustment strategy is adopted to eliminate the static error, so that the error between the target polarization voltage of the to-be-tested optical module in the information of the upper computer and the current output voltage of the power module is within a specified precision range, so as to automatically realize the polarization voltage test process.

[0019] Optionally, the power module comprises: a power supply input end, a transient suppression diode and an electronic switch.

[0020] The power supply input end is connected to a preset external power supply.

[0021] The first end of the transient suppression diode is connected in parallel between the power supply input end and the external power supply, and the second end of the transient suppression diode is grounded, for eliminating the surge voltage and transient high-voltage pulse of the power module, so that the input voltage of the power supply input end is within a safe range.

[0022] The control end of the electronic switch is connected to the microcontroller, and the output end of the electronic switch serves as the output end of the power module, outputting the polarization voltage of the to-be-tested optical module.

[0023] Optionally, the feedback voltage adjusting circuit comprises: a first resistor (R1), a second resistor (R2), a third resistor (R3) and a feedback circuit.

[0024] The first end of the first resistor (R1) is connected to the output end of the DAC, and the second end of the first resistor (R1) is connected to a feedback pin one of the feedback circuit.

[0025] A first end of the second resistor (R2) is connected to a feedback pin two of the feedback circuit, and a second end of the second resistor (R2) is grounded;

[0026] A first end of the third resistor (R3) is connected to a feedback pin three of the feedback circuit, and a second end of the third resistor (R3) is connected to an output end of the power module;

[0027] A feedback pin four of the feedback circuit is connected to a feedback end of the power module, and the feedback pin four outputs a feedback voltage to the power module when a voltage across the first resistor (R1) is balanced;

[0028] The resistance values of the second resistor (R2) and the third resistor (R3) are associated with an output voltage of the power module.

[0029] Optionally, a current sampling resistor, a current amplification circuit and a level conversion circuit are further arranged between the microcontroller and the output end of the power module.

[0030] The current sampling resistor is connected in series between the output end of the power module and a power input end of the to-be-tested optical module, and the resistance value of the current sampling resistor is in the order of milliohms.

[0031] The two input ends of the current amplification circuit are respectively connected to the two ends of the current sampling resistor, for amplifying the voltage sampled by the current sampling resistor to a voltage range that can be processed by the microprocessor.

[0032] A first end of the level conversion circuit is connected to an output end of the current amplification circuit, and a second end of the level conversion circuit is connected to the microprocessor, so that the microprocessor obtains a real-time current value of the to-be-tested optical module based on the periodically sampled voltage.

[0033] Optionally, in an initialization stage of the pull bias voltage adjustment system, the microcontroller is specifically configured to:

[0034] The microcontroller loads information of the upper computer and / or initialized control parameters, and controls the DAC to output at least two accurate voltage values, so as to adjust the power module to output a voltage value corresponding to the accurate voltage value;

[0035] Based on the accurate voltage value output by the DAC, an actual voltage value output by the power module corresponding to the accurate voltage value, and a target voltage value, the gain error coefficient α and the zero point offset β of the pull bias voltage adjustment system are obtained through linear regression.

[0036] The gain error coefficient α and the zero point offset β are used to obtain the output voltage V_Current of the power module eliminating inherent errors through formula (1) V_Current=α V_ADC_Reading+β, where V_ADC_Reading is the actual output voltage of the power module read by the ADC.

[0037] Optionally, in the voltage adjustment first stage of the adjustment test process of the pull-off voltage, the microcontroller is specifically used for:

[0038] The microcontroller obtains a static error e based on a target pull-off voltage V_Target in the host computer information and a current output voltage V_Current of the power module after eliminating the inherent error of hardware by the ADC acquisition, e = V_Target-V_Current;

[0039] It is judged whether the static error e is in a specified accuracy range, if yes, the first stage of adjusting the voltage is entered, and the pull-off voltage test process is automatically implemented; otherwise, the adaptive PID adjustment strategy is used to adjust parameters Kp, Kd and Ki, an adjustment amount ΔVSET of the analog voltage output by the DAC is obtained, and ΔVSET is applied to the adjustment end of the feedback voltage adjustment circuit to form an adjustment voltage for the adaptive closed-loop adjustment of the output voltage of the output end of the power module, so that the static error e is in the specified accuracy range.

[0040] Optionally, the adjustment amount ΔVSET of the analog voltage output by the DAC is obtained by adjusting the parameters Kp, Kd and Ki using the adaptive PID adjustment strategy, including:

[0041] If the static error e is in a first error interval, the adjusted parameters Kp, Kd and Ki are associated with the first error interval, and if the static error e is in a second error interval, the adjusted parameters Kp, Kd and Ki are associated with the second error interval;

[0042] Based on the adjusted Kp, Kd and Ki, the adjustment amount ΔVSET of the analog voltage output by the DAC is calculated using formula (2); formula (2) is: ΔVSET = Kp e+Ki∫e·dt+Kd·de / dt, t is a differential time;

[0043] The microcontroller resets the timer T = 0 when starting to adjust the parameters Kp, Kd and Ki using the adaptive PID adjustment strategy.

[0044] Wherein, the range of Kp associated with the first error interval is 0.1 to 1.0, the range of Kd is 0.001 to 0.05, and the range of Ki is 0 to 0.01; the range of Kp associated with the second error interval is 0.01 to 0.1, the range of Kd is 0.0005 to 0.01, and the range of Ki is 0.1 to 1.0.

[0045] Optionally, when the static error e is in the specified accuracy range, the first stage of adjusting the voltage is entered, and the pull-off voltage test process is automatically implemented, including:

[0046] Start the timer T of the microcontroller, when T keeps the specified stabilization time, and lock the output of the DAC, to enter the low-power monitoring mode;

[0047] Record the target bias voltage V_Target, T, and the output voltage V_Current of the power module collected by the ADC of the nth step, until n is greater than the specified N steps, to generate the bias voltage test result;

[0048] In the test process, the error e and whether it is in the specified accuracy range are judged in real time, if yes, the bias test process is executed, otherwise the first stage of adjusting the voltage is entered to adjust the output voltage of the power module.

[0049] Optionally, when the output voltage of the power module is adaptively adjusted, the output voltage VOUT of the power module and the analog voltage VSET output by the feedback voltage adjustment circuit and the DAC satisfy the following relationship:

[0050] VOUT=V_REF×[1+R3 / R2+(R3 / R1)×(VSET / V_REF-1)];

[0051] V_REF is the reference voltage inside the power module, which is a fixed value;

[0052] R3 is the resistance value of the third resistor in the feedback voltage adjustment circuit, R2 is the resistance value of the second resistor in the feedback voltage adjustment circuit, and R1 is the resistance value of the first resistor in the feedback voltage adjustment circuit.

[0053] Optionally, the microcontroller judges in real time whether the current output voltage V_Current of the power module collected by the ADC exceeds the set maximum range;

[0054] If yes, the electronic switch of the power module is controlled to be turned off, fault information is recorded, and prompt information of aborting the test is sent to the upper computer.

[0055] (Three) beneficial effects

[0056] The adaptive PID adjustment strategy is adopted to generate an analog voltage and act on the feedback voltage adjustment circuit, and then the bias voltage is directly adjusted through the feedback voltage adjustment circuit to eliminate the static error, which can improve the bias voltage adjustment accuracy to less than 1mV, and can actively and quickly suppress the changes of the optical module and external interference, greatly reducing the voltage ripple and drift of the bias voltage.

[0057] Secondly, the self-calibration is also used to eliminate the inherent error of hardware and the adaptive PID adjustment strategy is used to cope with dynamic error changes, so that the system has the ability of self-learning and optimization, and the system use threshold and dependence on component consistency are reduced.

[0058] Moreover, the application realizes one-key completion of a complex test flow with multiple voltage points and a holding time and automatic recording of data by automatically testing a sequence function, greatly improves test efficiency, guarantees high consistency and repeatability of a test process, and further improves applicability of batch quality inspection of optical modules on a production line. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 A hardware system architecture circuit diagram of an optical module high-precision polarization voltage adjustment system provided by an embodiment of the application is provided.

[0060] Figure 2 A flowchart of an optical module high-precision polarization voltage adjustment and test method provided by an embodiment of the application is provided.

[0061] Figure 3 A high-precision adaptive surge protection and automatic test sequence control algorithm flowchart provided by an embodiment of the application is provided.

[0062] Figure 4 A power module safety output control method flowchart provided by an embodiment of the application is provided.

[0063] Figure 5 A detailed step flowchart of step S2 in the optical module high-precision polarization voltage adjustment and test method provided by an embodiment of the application is provided.

[0064] Figure 6 A high-precision adaptive PID adjustment algorithm flowchart provided by an embodiment of the application is provided.

[0065] Figure 7 A detailed step flowchart of step S3 in the optical module high-precision polarization voltage adjustment and test method provided by an embodiment of the application is provided. DETAILED DESCRIPTION

[0066] In order to better explain the application and facilitate understanding, the application is described in detail below by specific embodiments with reference to the accompanying drawings.

[0067] REFERENCE Figure 1As shown, the high-precision bias voltage adjusting system for the optical module according to the embodiment of the present application comprises a host computer, a microcontroller MCU connected to the host computer, a power module connected to the optical module to be tested, and a feedback voltage adjusting circuit for adjusting the output voltage of the power module; the input end of the microcontroller MCU collects the output voltage of the power module through an ADC, and the ADC is arranged at the output end of the power module; the output end of the microcontroller MCU outputs an analog voltage to the adjusting end of the feedback voltage adjusting circuit through a connected DAC; the first end of the feedback voltage adjusting circuit is connected to the output end of the power module, the second end is connected to the feedback end of the power module, and the third end is grounded, and the feedback voltage adjusting circuit dynamically adjusts the output voltage of the power module based on the analog voltage, so as to make the power module output a target bias voltage; wherein, when the bias voltage adjusting system is initialized, the microcontroller MCU eliminates the inherent hardware error based on the information of the host computer and the data collected by the ADC, and in the process of adjusting and testing the bias voltage, the adaptive PID adjusting strategy is adopted to eliminate the static error, so that the error between the target bias voltage of the optical module to be tested in the information of the host computer and the current output voltage of the power module is within a specified accuracy range, so as to automatically realize the process of testing the bias voltage.

[0068] The adaptive PID adjusting strategy is adopted to generate the analog voltage and act on the feedback voltage adjusting circuit in the embodiment, and then the feedback voltage adjusting circuit directly adjusts the bias voltage to eliminate the static error, which can improve the bias voltage adjusting accuracy to less than 1mV, and can actively and quickly suppress the changes of the optical module and external interference, greatly reducing the voltage ripple and drift of the bias voltage. Secondly, the embodiment also eliminates the inherent hardware error through self-calibration and deals with the dynamic error changes through the adaptive PID adjusting strategy, so that the system has the ability of self-learning and optimization, reduces the use threshold of the system and the dependence on the consistency of components. In addition, the embodiment realizes one-key completion of the complex test process with multiple voltage points and holding time and automatic recording of data through the automatic test sequence function, greatly improves the test efficiency, ensures the high consistency and repeatability of the test process, and further improves the applicability of batch quality inspection of the optical module on the production line.

[0069] In order to better understand the above technical solutions, the exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided so that the present application can be more clearly, thoroughly understood, and the scope of the present application can be completely conveyed to those skilled in the art.

[0070] Specifically, reference is made to Figure 1As shown, the high-precision polarization voltage adjustment system of the optical module provided by the embodiment specifically comprises: a host computer, a microcontroller MCU connected to the host computer, a power module connected to the optical module to be tested (load), and a feedback voltage adjustment circuit for directly adjusting the output voltage of the power module.

[0071] Firstly, the host computer is used for setting the target polarization voltage V_Target of the optical module to be tested, the polarization test stable holding time T_Stable, and storing and displaying the polarization test report of the optical module to be tested after the system realizes the polarization voltage test of the optical module to be tested.

[0072] Then, the input end of the microcontroller MCU collects the output voltage of the power module through the ADC, and the ADC is arranged at the output end of the power module. The output end of the microcontroller MCU outputs an analog voltage VSET to the adjustment end of the feedback voltage adjustment circuit through the connected DAC. The output voltage of the power module is equivalent to the polarization voltage used for the polarization test of the optical module to be tested. After the microcontroller MCU collects the current output voltage V_Current of the power module, the microcontroller MCU analyzes the error of the output voltage, judges whether the static error e of the current output voltage V_Current and the target polarization voltage V_Target is in the specified accuracy range (the static error e is set to 1 mV according to the accuracy requirement of the high-precision polarization voltage test of the optical module), e=V_Target-V_Current; if yes, the first stage of the adjustment voltage is entered, the polarization voltage test process is automatically realized, and the corresponding polarization voltage test result is generated after the test is completed. Otherwise, the adaptive PID adjustment strategy is adopted to adjust the parameters Kp (proportional term), Kd (derivative term) and Ki (integral term), obtain the adjustment amount AVSET of the analog voltage output by the DAC, and apply AVSET to the adjustment end of the feedback voltage adjustment circuit, so as to form the adjustment voltage to adaptively close-loop adjust the output voltage of the output end of the power module, so that the static error e is in the specified accuracy range.

[0073] Further, before adjusting the bias voltage, the bias voltage adjustment system also needs to be initialized. In the initialization stage of the bias voltage adjustment system: first, the microcontroller MCU loads the information of the upper computer and / or the initialized control parameters, and controls the DAC to output at least two accurate voltage values. After the voltage is applied to the feedback voltage adjustment circuit, the feedback voltage information is generated and sent to the feedback circuit inside the power module, so that the power module outputs a voltage value corresponding to the accurate voltage value. Then, based on the accurate voltage value output by the DAC and the actual voltage value and the target voltage value output by the power module corresponding to the accurate voltage value, the gain error coefficient a and the zero point offset b of the bias voltage adjustment system are calculated and obtained by linear regression, and are stored in the non-volatile memory, so that in all subsequent control calculations, the error coefficient a and the zero point offset b are used to obtain the real voltage output by the power module, thereby eliminating the hardware inherent error of the system voltage acquisition at the software level. The gain error coefficient a and the zero point offset b are used to obtain the output voltage V_Current of the power module eliminating the hardware inherent error by formula (1) V_Current = a V_ADC_Reading + b, where V_ADC_Reading is the actual read output voltage of the power module collected by the ADC.

[0074] Further, when the static error e is within the specified accuracy range, the first stage of adjusting the voltage is entered, and the bias voltage test process is automatically implemented. The specific process can include: the microcontroller MCU locks the current DAC output value, starts the timer T of the microcontroller MCU (the timer T is used to time the bias test time of the current to-be-tested optical module), and enters a low-power consumption monitoring mode when T maintains a specified stable time. In this mode, the microcontroller MCU reduces the ADC sampling frequency (such as from 5 Hz to 1 Hz), and periodically checks the output voltage of the power module. Once it is found that the static error e exceeds the specified accuracy range due to changes in environmental temperature or load jump, the system immediately exits the monitoring mode and enters the first stage of adjusting the voltage to adjust the output voltage of the power module, so that the static error e of the output voltage of the power module is within the specified accuracy range. The microcontroller MCU records the target bias voltage V_Target, T, and the output voltage V_Current of the power module collected by the ADC in the low-power consumption monitoring mode, until n is greater than a specified number N of steps, and generates a bias voltage test result.

[0075] Further explanation, the pull voltage test process is an automatic test sequence, and the execution logic is as follows: first, the host computer sets a sequence containing N test steps, and each step defines the target pull voltage V_Target(n) and the stable holding time T_Stable(n), n=[1, N]; second, the microcontroller MCU loads the parameters V_Target(n) and T_Stable(n) of the nth test sequence from the non-volatile memory; third, the output voltage of the power module is stabilized at V_Target(n) through high-precision closed-loop adjustment, and when the static error e of the voltage enters the precision range (such as 1 mV), the stable timer is started, and the system will maintain the output voltage until the stable time reaches T_Stable(n). Fourth, the output voltage, current and state (pass / fail) of the optical module to be tested in the nth test sequence are associated with the sequence number n and stored; fifth, the test sequence index n is automatically incremented by 1, the system loads the next step parameters and repeats the above process until all N steps are executed; and fifth, after all the sequences are completed, the microcontroller MCU generates a test report containing detailed results of all steps, and uploads it to the host computer through the communication interface for display and storage.

[0076] Further, the adaptive PID adjustment strategy is adopted to adjust the parameters Kp, Kd and Ki to obtain the adjustment amount AVSET of the analog voltage output by the DAC, and the specific process can include: first, if the static error e is in the first error interval, the adjusted parameters Kp, Kd and Ki are associated with the first error interval, and if the static error e is in the second error interval, the adjusted parameters Kp, Kd and Ki are associated with the second error interval. Then, based on the adjusted Kp, Kd and Ki, the adjustment amount AVSET of the analog voltage output by the DAC is calculated by formula (2), and the formula (2) is: AVSET=Kp e+Ki∫e·dt+Kd·de / dt, t is the differential time. Finally, the microcontroller MCU resets the timer T=0 when starting to adjust the parameters Kp, Kd and Ki by the adaptive PID adjustment strategy. Wherein, the range of Kp associated with the first error interval is 0.1 to 1.0, the range of Kd is 0.001 to 0.05, and the range of Ki is 0 to 0.01; the range of Kp associated with the second error interval is 0.01 to 0.1, the range of Kd is 0.0005 to 0.01, and the range of Ki is 0.1 to 1.0.

[0077] Further explanation, assuming the system output voltage range is 0-5V, DAC is 16-bit (resolution about 0.076mV), static error e is 1mV, the first error interval is greater than 10mV, the first error interval is 1mV to 10mV. When |e|≥10mV, the system is in a large error range, at this time the PID parameter combination of large proportion, large differential, small integral is needed to be adopted, the proportional gain Kp and the differential gain Kd are set to a relatively large value, so that the system produces a strong adjustment action, quickly reduces the error, and improves the dynamic response speed; at the same time, the integral gain Ki is set to zero or a very small value, to prevent integral saturation and avoid large overshoot of the system, specifically: to improve the rapid response capability, the value range of Kp is adjusted to 0.1 to 1.0 (dimension: V / V or mV / mV), for example, when e=50mV, Kp=0.2 will produce an adjustment amount ΔVSET of 10mV; to predict the trend of error and provide damping, prevent large overshoot due to inertia in the process of rapid pursuit, the value range of Kd is adjusted to 0.001 to 0.05 (dimension: V / (V / s) or mV / (mV / s)); to reduce severe overshoot due to integral saturation when reaching the target point, the value range of Ki is adjusted to 0 to 0.01 (dimension: V / (V·s) or mV / (mV·s)), if not zero, Ki should be set very small, so that it has a significant impact on the time scale of seconds.

[0078] When 1m≤|e|<10mV, the system is in a small error range, at this time the PID parameter combination of small proportion, large integral, medium differential is needed to be adopted, the proportional gain Kp is significantly reduced to suppress the oscillation near the target value, the differential gain Kd maintains a moderate value to provide the necessary damping, and the integral gain Ki is significantly increased to become the dominant adjustment action, through accumulation and elimination of small static error, to ensure that the final control accuracy meets the requirement of <1mV, specifically: to prevent the system from oscillating around the target value, the value range of Kp is adjusted to 0.01 to 0.1 (dimension: V / V or mV / mV); to continue to provide damping and suppress any small oscillation caused by the integral term, the value range of Kd is adjusted to 0.0005 to 0.01 (dimension: V / (V / s) or mV / (mV / s)); to eliminate very small static error and make the system stable at the accurate target value, the value range of Ki is adjusted to 0.1 to 1.0 (dimension: V / (V·s) or mV / (mV·s)).

[0079] Secondly, referring to Figure 1As shown, the power module is preferably a DC-DC power module or an LDO power module, which includes a power input, a transient voltage suppression diode, and an electronic switch. The power input is connected to a preset external power source. The first end of the transient voltage suppression diode is connected in parallel between the power input and the external power source, and the second end of the transient voltage suppression diode is grounded, for eliminating the surge voltage and transient high-voltage pulse of the power module, so as to protect the voltage conversion module and the entire bias voltage regulation system in the subsequent stage within a safe range of input voltage of the power input. The electronic switch is preferably a MOSFET tube, the control end of which is connected to the microcontroller MCU, and the output end of which serves as the output end of the power module, for outputting the bias voltage of the light module to be tested. The MOSFET tube is connected in series between the output end of the power module and the light module to be tested, and is controlled by a GPIO pin of the microcontroller MCU through a driving circuit, as the last software protection switch of the bias voltage regulation system, which is turned on when the system is working normally, and is turned off quickly when a fault (such as overvoltage, undervoltage, or overcurrent) is detected, so as to completely cut off the power supply of the light module by the power module.

[0080] Further, in each control cycle, the microcontroller MCU reads the output voltage V_Current and the output current I_Current of the power module sampled by the ADC before executing the output accuracy judgment of the power module, and judges whether V_Current or I_Current exceeds the preset safe range. If V_Current or I_Current exceeds the preset safe range, the system is determined to be faulty, and the microcontroller MCU performs a protection action: first, controls the GPIO output to disconnect the MOSFET tube connected in series on the output path, to realize physical power-off; second, sets the DAC output to zero; and finally, records the fault log (including the fault type, the test step at the time of occurrence, etc.), and suspends the current test sequence.

[0081] Then, referring to Figure 1As shown, the feedback voltage regulation circuit includes a first resistor R1, a second resistor R2, a third resistor R3, and a feedback circuit FB. The first end of the first resistor R1 is not connected to a fixed reference source or ground, but is directly connected to the output end of the DAC to achieve adjustable voltage of the first resistor R1, and the second end of the first resistor R1 is connected to the feedback pin one of the feedback circuit. The first end of the second resistor R2 is connected to the feedback pin two of the feedback circuit, the second end of the second resistor R2 is grounded to provide a fixed ground path for the feedback circuit, and the second resistor R2 is associated with the output voltage of the power module for determining the basic voltage regulation range. The first end of the third resistor R3 is connected to the feedback pin three of the feedback circuit, and the second end of the third resistor R3 is connected to the output end of the power module. The third resistor R3 serves as a pull-up resistor of the FB feedback circuit, and its resistance value is also associated with the output voltage of the power module, and cooperates with the second resistor R2 to determine the basic proportion of the fixed voltage output. The feedback pin four of the feedback circuit is connected to the feedback end of the power module, and the feedback pin four outputs a feedback voltage to the power module when the voltage across the first resistor R1 is balanced, so as to feed back stable voltage information to the power module when the output voltage is adjusted to meet the static error, so that the output voltage of the power module is the voltage value meeting the static error.

[0082] Further, the voltage regulation logic of the feedback voltage regulation circuit can include basic voltage regulation logic and variable voltage regulation logic. The basic voltage regulation logic is applied to the fixed voltage output scenario, and the output voltage VOUT of the power module and the feedback voltage VFB of the FB node satisfy the following relationship: VOUT=V_REF×(1+R3 / R2), V_REF is the reference voltage inside the power module, which is usually a fixed value, such as 0.8V, 1.25V, etc., and at this time VFB=V_REF. When there is no need to adjust the output voltage, the microcontroller MCU controls the DAC to output a fixed analog voltage VSET, so that the equivalent resistance value of R1 does not affect the feedback proportion of R2, at this time the circuit realizes fixed voltage output through the fixed resistance values of R3 and R2, which is consistent with the traditional scheme, ensuring the compatibility of the circuit.

[0083] The variable voltage adjustment logic can be applied to any voltage output scenario. When the pull voltage of the optical module (i.e. the output voltage of the power module) needs to be adjusted, the microcontroller MCU realizes the adjustment of the output voltage through the following steps: first, the microcontroller MCU calculates the required DAC output analog voltage VSET according to the voltage requirement of the optical module (such as obtained through the state feedback signal of the optical module, or determined through the control instruction issued by the upper computer), and sends the corresponding digital control signal to the DAC module. Second, the DAC converts the digital signal to analog voltage VSET, and outputs VSET to the first end of R1. At this time, the voltage difference between the two ends of R1 is VSET-VFB, and according to Ohm's law, current I1=(VSET-VFB) / R1 will be generated in R1. Third, at the FB node, the current satisfies Kirchhoff's current law: the current flowing into the FB node is equal to the current flowing out of the FB node, where the current I3=(VOUT-VFB) / R3 generated by R3 (from VOUT to FB node), the current I2=VFB / R2 generated by R2 (from FB node to ground), and the current I1 (the direction depends on the size of VSET and VFB, if VSET>VFB, then I1 flows from R1 FB node; otherwise, it flows from FB node to R1). Fourth, according to the current balance relationship, the correlation formula of VOUT and VSET can be derived (taking the case that I1 flows from R1 to FB pin as an example): I3=I2+I1, (VOUT-VFB) / R3=VFB / R2+(VSET-VFB) / R1, combined with the internal V_REF=VFB of the power module, it can be deduced that when the output voltage of the power module is adaptively adjusted, the output voltage VOUT of the power module and the feedback voltage adjustment circuit and the analog voltage VSET output by the DAC satisfy the following relationship: VOUT=V_REF×[1+R3 / R2+(R3 / R1)×(VSET / V_REF-1)].

[0084] Finally, a current sampling resistor R_sense, a current amplification circuit, and a level conversion circuit are further arranged between the output end of the microcontroller MCU and the output end of the power module. The current sampling resistor R_sense is connected in series between the output end of the power module and the power input end of the optical module to be tested, and the load current I_LOAD flows through the resistor. The current sampling resistor R_sense is a small resistance with a milliohm level, high precision, and low temperature coefficient (for example, 5 mΩ or 10 mΩ). The two input ends of the current amplification circuit are respectively connected to the two ends of the current sampling resistor R_sense, and are used to amplify the voltage sampled by the current sampling resistor R_sense to a voltage range that can be processed by the microprocessor. The current amplification circuit is a differential amplification circuit composed of an operational amplifier with a high common-mode rejection ratio. The two input ends of the amplifier are respectively connected to the two ends of R_sense to collect the small differential voltage drop V_sense generated by the resistor. V_sense = I_LOAD x R_sense. The first end of the level conversion circuit is connected to the output end of the current amplification circuit, and the second end of the level conversion circuit is connected to the microprocessor. The microprocessor obtains the real-time current value of the optical module to be tested based on the periodically sampled voltage. The level conversion circuit first amplifies the weak V_sense signal to a voltage range V_OUT (for example, 0-3.3V) suitable for the microcontroller MCU. The gain G is designed according to the resistance of R_sense and the ADC range of the microcontroller MCU, so that V_OUT is close to the full range of the ADC (for example, 3.0V) when the maximum test current I_LOAD_MAX is reached. Then, the ADC converts the amplified V_sense signal into a digital signal. Finally, the real-time load current value I_LOAD is calculated according to the formula I_LOAD = V_OUT / (G x R_sense).

[0085] On the other hand, based on the above-mentioned high-precision bias voltage adjustment system for optical modules, the embodiment proposes a high-precision bias voltage adjustment and testing method for optical modules, as shown in Figure 2 and 3 The method comprises the following steps.

[0086] S1, the output voltage V_ADC_Reading of the power module is collected by the ADC, and the output voltage is corrected according to the gain error coefficient α and the zero point offset β of the bias voltage adjustment system to obtain the real-time output voltage V_Current of the power module.

[0087] S2, according to the static error e of the real-time output voltage V_Current and the target polarization test voltage V_Target, an adaptive PID adjustment strategy is adopted to adjust the parameters Kp, Kd and Ki, and the adjustment amount AVSET of the analog voltage output by the DAC is obtained, so that the adjustment amount AVSET acts on the adjustment end of the feedback voltage adjustment circuit to form an adjustment voltage to adaptively close-loop adjust the output voltage of the power module output end.

[0088] S3, the output voltage V_Current adjusted in the specified accuracy range is taken as the polarization test voltage of the optical module to be tested to test the polarization voltage of the optical module, and the test data of the specified stable time T_Stable is collected to generate the polarization voltage test report of the optical module to be tested.

[0089] Further, referring to Figure 4 , before step S2, further comprising:

[0090] G1, judge whether V_Current exceeds the set safety voltage range.

[0091] G2a, if V_Current exceeds the set safety voltage range, output the power-off control instruction to the control end of the electronic switch to execute the power-off control of the power module through the electronic switch.

[0092] G2b, if V_Current does not exceed the set safety voltage range, the output current I_Current of the power module is collected by current collection, and it is judged whether I_Current exceeds the set safety current range.

[0093] G3a, if I_Current exceeds the set safety current range, output the power-off control instruction to the control end of the electronic switch to execute the power-off control of the power module through the electronic switch.

[0094] G3b, if I_Current does not exceed the set safety current range, execute step S2.

[0095] Further, referring to Figure 5 and 6 , step S2 can include the following substeps:

[0096] S21, obtain the static error e of the output voltage V_Current and the target polarization test voltage V_Target, and judge the error interval to which the static error e belongs.

[0097] S22a, when e is greater than the first error threshold, a first control voltage signal is generated by calling a first set of PID parameters containing a proportional coefficient ranging from 0.1 to 1.0, a differential coefficient ranging from 0.001 to 0.05, and an integral coefficient ranging from 0 to 0.01, to control the adjustment amount AVSET1 of the analog voltage output by the DAC.

[0098] S22b, when e is between the first error threshold and the second error threshold, a second control voltage signal is generated by calling a second set of PID parameters containing a proportional coefficient ranging from 0.01 to 0.1, a differential coefficient ranging from 0.0005 to 0.01, and an integral coefficient ranging from 0.1 to 1.0, to control the adjustment amount AVSET2 of the analog voltage output by the DAC.

[0099] S22c, when e is less than the second error threshold, the current output voltage of the power supply module is taken as the pull test voltage of the optical module to be tested, and the pull voltage test timing of the optical module to be tested is started.

[0100] Further, referring to Figure 7 As shown in FIG. 3, step S3 can include the following sub-steps:

[0101] S31, the output voltage V_Current after adjustment within the specified accuracy range is applied to the optical module to be tested as the pull test voltage of the current round, and the test data of the specified stable time T_Stable is collected.

[0102] S32, after the end of the current round of test, switch to the next preset pull test voltage target value, repeat the voltage adjustment, application and data collection until all the preset pull test voltage rounds are completed.

[0103] S33, based on the performance parameter data collected in all test rounds, the corresponding pull test voltage value and test time information are associated for data integration and analysis, and the optical module pull voltage test report containing the test conditions and performance parameter change curve is generated.

[0104] In summary, the embodiment of the present application proposes a high-precision bias voltage adjustment system for an optical module and a testing method thereof. Firstly, in order to overcome the low precision of the prior art, the present application introduces a high-precision closed-loop feedback architecture combining DAC and ADC, which compensates for hardware errors through software algorithms, and improves the adjustment and stability precision of the bias voltage of the optical module to within ±1mV. Secondly, in order to overcome the poor stability of the prior art, the present application designs a closed-loop PID control algorithm based on real-time sampling, which enables the system to quickly respond and suppress voltage disturbances caused by load changes, power ripples and temperature drifts, and ensures long-term dynamic stability of the output voltage at the target value. Thirdly, in order to overcome the low degree of intelligence of the prior art, the present application provides an adaptive PID control strategy and a power-on self-calibration process, which enables the system to automatically adjust the control parameters to adapt to different loads, and automatically calibrate the initial error, achieving plug-and-play high-precision adjustment without manual intervention. Fourthly, in order to overcome the questionable reliability of the prior art, the present application provides a composite protection mechanism combining software and hardware through transient voltage suppressor diodes, electronic switches and current sampling circuits, which realizes surge suppression, overvoltage and overcurrent protection, and effectively safeguards the safety of the testing system and the optical module under test. Finally, in order to overcome the low testing efficiency of the prior art, the present application provides an automatic testing sequence execution and result recording function, which enables the system to automatically complete complex bias testing at multiple voltage points with a holding time according to the preset sequence, and automatically generates a test report, greatly improving the testing efficiency and data traceability.

[0105] The specific structure and modifications of the system / device can be understood by those skilled in the art based on the method described in the above embodiments of the present application, and therefore will not be described here again. Any system / device used in the method of the above embodiments of the present application belongs to the scope of protection of the present application.

[0106] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can be in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can be in the form of a computer program product implemented on one or more computer usable storage media containing computer usable program code (including but not limited to disk storage, CD-ROM, optical storage, etc.).

[0107] The present application is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams can be implemented by computer program instructions, and the combination of flows and / or blocks in the flowcharts and / or block diagrams.

[0108] It should be noted that the words "comprise" and "comprising" in this description do not exclude the presence of elements or

[0109] Furthermore, it is noted that the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments or examples. It will also be readily appreciated that the terms "comprise", "comprising", "include", "including", "has", "having" or variants thereof are to be construed in a non-exclusive sense, namely permitting the presence of other features, structures, or characteristics not expressly mentioned. It is also noted that the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

[0110] Although preferred embodiments of the application have been described, those skilled in the art will be able to make additional modifications and variations without departing from the spirit and scope of the application.

[0111] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the application can be practiced otherwise than as specifically described.

Claims

1. A high-precision bias voltage adjustment system for an optical module, characterized in that, The application relates to a pull-off voltage test system for a light module. The system comprises a host computer, a microcontroller connected to the host computer, a power module connected to the light module to be tested, and a feedback voltage regulating circuit for regulating the output voltage of the power module. The input end of the microcontroller collects the output voltage of the power module through an ADC, and the ADC is arranged at the output end of the power module. The output end of the microcontroller outputs an analog voltage to the regulating end of the feedback voltage regulating circuit through a connected DAC. The first end of the feedback voltage regulating circuit is connected to the output end of the power module, the second end is connected to the feedback end of the power module, and the third end is grounded. The feedback voltage regulating circuit dynamically regulates the output voltage of the power module based on the analog voltage, so that the power module outputs a target pull-off voltage. The feedback voltage regulating circuit comprises a first resistor (R1), a second resistor (R2), a third resistor (R3), and a feedback circuit.

2. The high precision polarization bias voltage adjusting system for optical module according to claim 1, characterized in that, The first end of the first resistor (R1) is connected to the output end of the DAC, and the second end of the first resistor (R1) is connected to the feedback pin one of the feedback circuit. The first end of the second resistor (R2) is connected to the feedback pin two of the feedback circuit, and the second end of the second resistor (R2) is grounded. The first end of the third resistor (R3) is connected to the feedback pin three of the feedback circuit, and the second end of the third resistor (R3) is connected to the output end of the power module. The feedback pin four of the feedback circuit is connected to the feedback end of the power module, and outputs a feedback voltage to the power module when the voltage across the first resistor (R1) is balanced.

3. The high precision bias voltage adjustment system for optical module according to claim 1, characterized in that, The resistance values of the second resistor (R2) and the third resistor (R3) are associated with the output voltage of the power module. When the pull-off voltage regulating system is initialized, the microcontroller eliminates the inherent hardware error based on the information of the host computer and the data collected by the ADC. During the pull-off voltage regulating test process, the adaptive PID regulating strategy is adopted to eliminate the static error, so that the error between the target pull-off voltage of the light module in the information of the host computer and the current output voltage of the power module is within a specified accuracy range, and the pull-off voltage test process is automatically realized. The power module comprises a power input end, a transient suppression diode, and an electronic switch. The power input end is connected to a preset external power supply. The first end of the transient suppression diode is connected in parallel between the power input end and the external power supply, and the second end of the transient suppression diode is grounded. The control end of the electronic switch is connected to the microcontroller, and the output end of the electronic switch serves as the output end of the power module and outputs the pull-off voltage of the light module to be tested. A current sampling resistor, a current amplification circuit, and a level conversion circuit are further arranged between the output end of the microcontroller and the output end of the power module. The current sampling resistor is connected in series between the output end of the power module and the power input end of the light module to be tested, and the resistance value of the current sampling resistor is in the order of milliohms. The two input ends of the current amplification circuit are respectively connected to the two ends of the current sampling resistor, and the current amplification circuit amplifies the voltage sampled by the current sampling resistor to a voltage range that can be processed by the microprocessor. The first end of the level conversion circuit is connected to the output end of the current amplification circuit, and the second end of the level conversion circuit is connected to the microprocessor, so that the microprocessor obtains the current value of the optical module to be tested in real time based on the periodically sampled voltage.

4. The high precision bias voltage adjustment system for optical module according to claim 1, characterized in that, In the initialization stage of the bias voltage adjustment system, the microcontroller is specifically used for: The microcontroller loads the information of the upper computer and / or the initialized control parameters, and controls the DAC to output at least two accurate voltage values, so as to adjust the voltage value corresponding to the accurate voltage value output by the power module; Based on the accurate voltage value output by the DAC, the actual voltage value output by the power module corresponding to the accurate voltage value, and the target voltage value, the gain error coefficient α and the zero offset β of the bias voltage adjustment system are obtained through linear regression; wherein the gain error coefficient a and the zero offset b are used to obtain the output voltage V_Current of the power module that eliminates the inherent error of the hardware by the formula (1) V_Current = a V_ADC_Reading + b, V_ADC_Reading being the actual read output voltage of the power module collected by the ADC.

5. The high precision polarization bias voltage adjusting system for optical module according to claim 4, characterized in that, In the first stage of the voltage adjustment process of the bias voltage adjustment test, the microcontroller is specifically used for: The microcontroller obtains the static error e based on the target bias voltage V_Target in the upper computer information and the current output voltage V_Current of the power module after the ADC acquisition eliminates the inherent error of the hardware, e = V_Target-V_Current; If the static error e is in the specified accuracy range, the first stage of the voltage adjustment is entered, and the bias voltage test process is automatically implemented; otherwise, the adaptive PID adjustment strategy is used to adjust the parameters Kp, Kd and Ki, the adjustment amount ΔVSET of the analog voltage output by the DAC is obtained, and ΔVSET is applied to the adjustment end of the feedback voltage adjustment circuit to form the output voltage of the power module, so that the static error e is in the specified accuracy range.

6. The high precision bias voltage adjustment system for optical module according to claim 5, characterized in that, The adjustment amount ΔVSET of the analog voltage output by the DAC is obtained by adjusting the parameters Kp, Kd and Ki using the adaptive PID adjustment strategy, including: If the static error e is in the first error interval, adjust Kp, Kd and Ki, so that the adjusted parameters are associated with the first error interval; if the static error e is in the second error interval, adjust Kp, Kd and Ki, so that the adjusted parameters are associated with the second error interval; Based on the adjusted Kp, Kd and Ki, an adjustment amount AVSET of the analog voltage of the DAC output is calculated by using formula (2); formula (2) is: AVSET=Kp e+Ki∫e·dt+Kd·de / dt, t is differential time; The microcontroller resets the timer T=0 when it starts to adjust the parameters Kp, Kd and Ki using the adaptive PID adjustment strategy. Wherein, the range of Kp associated with the first error interval is 0.1 to 1.0, the range of Kd is 0.001 to 0.05, and the range of Ki is 0 to 0.01; the range of Kp associated with the second error interval is 0.01 to 0.1, the range of Kd is 0.0005 to 0.01, and the range of Ki is 0.1 to 1.

0.

7. The high precision bias voltage adjustment system for optical module according to claim 5, characterized in that, If the static error e is in the specified accuracy range, the first stage of the voltage adjustment is entered, and the bias voltage test process is automatically implemented, including: Start the timer T of the microcontroller, and when T remains in the specified stable time, lock the output of the DAC to enter the low-power monitoring mode; Record the target bias voltage V_Target, T, and the output voltage V_Current of the power module collected by the ADC at the nth step, until n is greater than the specified N steps, and generate the bias voltage test result; In the test process, the error e is judged in real time and whether it is in the specified accuracy range, if yes, the pull bias test process is executed, otherwise, the first stage of adjusting the voltage is entered to adjust the output voltage of the power module.

8. The high precision bias voltage adjustment system for optical module according to claim 5, characterized in that, When the output voltage of the power module is adaptively adjusted, the output voltage VOUT of the power module and the analog voltage VSET output by the feedback voltage adjusting circuit and the DAC satisfy the following relationship: VOUT=V_REF×[1+R3 / R2+(R3 / R1)×(VSET / V_REF-1)]; V_REF is the reference voltage inside the power module, which is a fixed value; R3 is the resistance value of the third resistor in the feedback voltage adjusting circuit, R2 is the resistance value of the second resistor in the feedback voltage adjusting circuit, and R1 is the resistance value of the first resistor in the feedback voltage adjusting circuit.

9. The high-precision pull bias voltage adjusting system of the optical module according to claim 5, characterized in that, The microcontroller judges in real time whether the current output voltage V_Current of the power module collected by the ADC exceeds the set maximum range; If yes, the electronic switch of the power module is controlled to be turned off, the fault information is recorded, and the prompt information of stopping the test is sent to the upper computer.

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