APD working voltage automatic configuration method, system and processing chip

Abstract

The present application relates to an automatic configuration method, system and processing chip for the APD working voltage. The method includes sequentially setting the duty cycle of the input signal of the adjustable high-voltage module according to the value of each duty cycle in the set duty cycle interval; and synchronously detecting the corresponding average output voltage of the adjustable high-voltage module when it is in the input signal through the voltage detection module; sequentially calculating the ratio between the duty cycle difference and the average output voltage difference obtained by two adjacent detections, obtaining the first turning point voltage and the second turning point voltage, and calculating the voltage value required for the APD to be configured based on the turning point voltage; and realizing the automatic configuration of the working voltage of the APD to be configured. By adopting the above technical solution, while ensuring the stability of the APD gain, there is no need to measure and preset its working curve in advance, which solves the problem of high production or use costs of APD devices.

Description

Technical Field

[0001] The present application relates to the field of avalanche photodiode (APD) circuit control, and in particular to an automatic configuration method, system and processing chip for an APD working voltage. Background Art

[0002] Avalanche photodiode (APD) is a photodetector with gain effect. It is widely used in optoelectronic systems due to its high sensitivity, low noise, fast response speed and high amplification gain. The principle is that after the absorption layer absorbs the photons of incident light to generate carriers, under extremely high external bias, the carriers will accelerate and collide with the lattice to generate new carriers. This process continuously generates new carriers, similar to the process of avalanche amplification, thus playing the role of optical power amplification.

[0003] like Figure 1 As shown, the APD works under reverse bias. Under certain temperature conditions, the higher the bias, the greater the amplification gain M. When the external reverse bias UR increases to close to the breakdown voltage UBR of the APD, the amplification gain M will approach infinity, and the PN junction of the APD will break down.

[0004] In applications, in order to obtain a better signal-to-noise ratio (SNR), the APD operating voltage (i.e., reverse bias voltage UR) cannot exceed UBR and is usually set to 0.8~0.95UBR.

[0005] The breakdown voltage UBR of APD is related to the operating temperature of the device. When the temperature rises, the breakdown voltage UBR will increase; when the temperature decreases, UBR will decrease. Therefore, when APD is working, it is usually necessary to adjust the operating voltage according to the temperature to keep the amplification gain as stable as possible.

[0006] At present, some APD gain stabilization control uses constant temperature control, which maintains the working temperature of the APD unchanged by heating or cooling. This method requires the deployment of heating and cooling equipment or devices, has high requirements for temperature control accuracy, consumes large power during operation, has a complex structure, and has limited adaptability to ambient temperature.

[0007] Some solutions are to measure the high-voltage temperature curve (i.e., working curve) of the APD in advance and save it in the system. By measuring the current temperature value, the working voltage corresponding to the current temperature value is obtained from the high-voltage temperature curve stored in the system for adjustment. Although this method has a relatively simple circuit structure and control logic, due to the consistency differences caused by factors such as different manufacturers and different batches of APD devices, this method requires measuring and saving the temperature curve for a single APD, and a large-scale testing process will result in higher production or use costs. Summary of the invention

[0008] In order to solve the differences in individual APD operating voltages and temperatures, automatically detect and adjust the currently required operating voltage, eliminate the need for advance measurement and preset working curves, and reduce costs, the present application provides an APD operating voltage automatic configuration method, system, and processing chip.

[0009] In a first aspect, the present application provides a method for automatically configuring an APD operating voltage:

[0010] According to the value of each duty cycle in the set duty cycle interval, the duty cycle of the input signal of the adjustable high-voltage module is set in sequence; and the corresponding average output voltage of the adjustable high-voltage module when the input signal is synchronously detected by the voltage detection module; each input signal with different duty cycles makes the adjustable high-voltage module output an average output voltage correspondingly; the output end of the adjustable high-voltage module is connected to the cathode of the APD to be configured; the minimum value of each average output voltage is less than 0.5U BR , the maximum value among the average output voltages>U BR , the U BR Indicates the calibrated breakdown voltage of the APD to be configured;

[0011] Calculate the ratio between the duty cycle difference and the average output voltage difference obtained by two consecutive detections (PWM i - PWM i-1 ) / (U i -U i-1 );PWM i Represents the duty cycle of the i-th input signal, PWM i-1 represents the duty cycle of the i-1th input signal, U i represents the ith average output voltage, U i-1 represents the i-1th average output voltage;

[0012] Determining whether the ratio is greater than a first preset threshold;

[0013] If so, then U i As the first turning point voltage;

[0014] The first turning point voltage U i After that, continue to calculate the ratio between the duty cycle difference obtained from two consecutive detections and the average output voltage difference (PWM k - PWM k-1 ) / (U k -U k-1 );PWM k Indicates the duty cycle of the kth input signal, PWM k-1 represents the duty cycle of the k-1th input signal, Uk represents the kth average output voltage, U k-1 represents the k-1th average output voltage; where PWM k Greater than PWM i ;

[0015] Determining whether the ratio is greater than a second preset threshold;

[0016] If so, then U k as the second turning point voltage;

[0017] Based on the first turning point voltage and the second turning point voltage, a voltage value required to be configured of the APD to be configured is calculated; the voltage value required to be configured is greater than the first turning point voltage and less than the second turning point voltage;

[0018] The voltage value required to be configured is used as the working voltage of the APD to be configured and loaded to the cathode of the APD to be configured, so as to realize automatic configuration of the working voltage of the APD to be configured.

[0019] By adopting the above technical solution, while ensuring the stability of the APD gain, there is no need to measure and preset its working curve in advance, thus solving the problem of high production or use costs of APD devices.

[0020] Optionally, the duty cycle values ​​in the set duty cycle interval are arranged at equal intervals.

[0021] Optionally, the first preset threshold is set in the following manner:

[0022] Calculate the ratio between the duty cycle difference obtained from the first i-1 consecutive detections and the average output voltage difference (PWM j -PWM j-1 ) / (U j -U j-1 ) ;

[0023] The first preset threshold is set to , α is the setting multiple, and the value of α is 1.5~2.

[0024] Optionally, the second preset threshold is set in the following manner:

[0025] Calculate the ratio between the duty cycle difference obtained from two consecutive detections from the ith to the k-1th and the average output voltage difference (PWM t - PWM t-1 ) / (U t -U t-1 ) ;

[0026] The second preset threshold is set to βm2, where β is a set multiple and the value of β is 1.5~2.

[0027] Optionally, the calculating, based on the first turning point voltage and the second turning point voltage, a voltage value required to be configured for the APD to be configured comprises:

[0028] Calculate the average value 1 / 2 of the first turning point voltage and the second turning point voltage (U i +U k );

[0029] The average value 1 / 2 (U i +U k ) as the voltage value required to be configured by the APD to be configured.

[0030] Optionally, the APD operating voltage automatic configuration method further includes:

[0031] Based on the one-to-one correspondence between different duty cycles of each input signal and each average output voltage, the average output voltage is used as the horizontal coordinate and the duty cycle is used as the vertical coordinate, and smoothing filtering is performed to establish a relationship diagram between the duty cycle and the output voltage;

[0032] The duty cycle of the required configuration corresponding to the required configured voltage value is determined through the relationship diagram, and then the duty cycle of the input signal of the adjustable high-voltage module is controlled to be the duty cycle of the required configuration, so as to realize automatic configuration of the working voltage of the APD to be configured.

[0033] Optionally, before sequentially setting the duty cycle of the input signal of the adjustable high-voltage module according to the value of each duty cycle in the set duty cycle interval, the method further includes:

[0034] It is determined that a configuration instruction is received; the configuration instruction is used to instruct automatic configuration of the operating voltage of the APD to be configured.

[0035] Optionally, the determining that a configuration instruction is received includes:

[0036] Obtaining the historical ambient temperature corresponding to the APD to be configured when configuring the current operating voltage;

[0037] Collecting the current ambient temperature of the APD to be configured through a temperature monitoring module;

[0038] Calculating the temperature difference between the current ambient temperature and the historical ambient temperature;

[0039] If it is determined that the temperature difference is greater than the set temperature difference threshold, it is determined that the configuration instruction has been received; if it is determined that the temperature difference is not greater than the set temperature difference threshold, the APD to be configured is controlled to maintain the current operating voltage and continue to operate.

[0040] In a second aspect, the present application provides an APD operating voltage automatic configuration system:

[0041] It includes an adjustable high voltage module, a processor module, a voltage detection module and an APD;

[0042] The input end of the adjustable high voltage module is connected to the processor module, and the output end of the adjustable high voltage module is connected to the voltage detection module and the cathode of the APD; the adjustable high voltage module is used to receive the input signal of the processor module to convert the input power into a corresponding voltage and output it to the voltage detection module and the cathode of the APD;

[0043] The voltage detection module is used to detect the output voltage of the adjustable high-voltage module and send it to the processor module;

[0044] The processor module is used to implement any of the above APD working voltage automatic configuration methods.

[0045] In a third aspect, the present application provides a processing chip, which can execute a computer program to implement the APD operating voltage automatic configuration method as described in any one of the above items.

[0046] In a fourth aspect, the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program; the computer program can be executed by a processor to implement the APD operating voltage automatic configuration method as described in any of the above items.

[0047] In a fifth aspect, the present application also provides a computer program product, including a computer program, which can be executed by a processor to implement the APD operating voltage automatic configuration method as described in any of the above items.

[0048] By adopting the above technical solution, a computer program carrier of the APD working voltage automatic configuration method is provided.

[0049] In summary, this application at least includes the following beneficial technical effects:

[0050] It can solve the differences in individual working voltage and temperature of APDs, automatically detect and adjust the currently required working voltage, and does not require advance measurement and preset working curves, thus reducing production or use costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1A diagram showing the relationship between the APD amplification gain and the reverse bias voltage in the embodiment of the present application;

[0052] Figure 2 This is a schematic diagram of the structure of an APD working voltage automatic configuration system in an embodiment of the present application;

[0053] Figure 3 This is a schematic diagram of another APD working voltage automatic configuration system structure in an embodiment of the present application;

[0054] Figure 4 This is a circuit structure diagram corresponding to an APD working voltage automatic configuration system in an embodiment of the present application;

[0055] Figure 5 This is a flow chart of the method for automatically configuring the APD working voltage in an embodiment of the present application;

[0056] Figure 6 is a relationship diagram between dark current and reverse bias voltage of the APD in an embodiment of the present application;

[0057] Figure 7 A diagram showing the relationship between the duty cycle and output voltage of the adjustable high-voltage module in an embodiment of the present application;

[0058] Figure 8 4 is a curve diagram showing the relationship between the output voltage of the adjustable high-voltage module and the duty cycle difference in the embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0060] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to be used as limitations to the present application. As used in the specification and the appended claims of the present application, the singular expressions "one", "a kind of", "said", "above", "the" and "this" are intended to also include plural expressions, unless there is a clear contrary indication in its context. It should also be understood that the term "and / or" used in the present application refers to and includes any or all possible combinations of one or more listed items. The term "exemplary" means "used as an example, embodiment or illustrative", and any embodiment described as "exemplary" here does not need to be interpreted as being superior to or better than other embodiments. The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as implying or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" can expressly or implicitly include one or more of these features, and in the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0061] Those skilled in the art know that the APD amplification gain is positively correlated with the reverse bias voltage loaded to its cathode, or more precisely, it is positively correlated with the ratio of the reverse bias voltage to its actual breakdown voltage. In order to keep the APD amplification gain stable, it is necessary to keep the ratio of the reverse bias voltage to its actual breakdown voltage stable. If the actual breakdown voltage remains unchanged, it is only necessary to ensure that the reverse bias voltage input to the APD remains stable. However, in fact, since the actual breakdown voltage of the APD changes dynamically with the ambient temperature during operation, in order to keep the amplification gain stable, either the ambient temperature is kept constant, so there is no need to adjust the reverse bias voltage; or the reverse bias voltage is adjusted dynamically as the ambient temperature changes. The first method requires the deployment of refrigeration and heating equipment so that the APD works in a constant temperature environment. Obviously, this method has a complicated construction process, high cost of ancillary facilities, and high power consumption during use, and the cost of use cannot meet the demand. The second method requires testing the corresponding working curves at different temperature values ​​for each APD device (such as Figure 1 ), and then pre-set it into the system. This testing process is labor-intensive and requires the construction of a testing site or laboratory, so the cost is still high.

[0062] In this regard, an embodiment of the present application provides a method and system for automatically configuring an APD operating voltage.

[0063] refer to Figure 2 The APD working voltage automatic configuration method provided in the embodiment of the present application is mainly used for Figure 2 In the APD working voltage automatic configuration system shown, the system at least includes an adjustable high voltage module, a processor module, a voltage detection module and an APD;

[0064] Among them, the input end of the adjustable high-voltage module is connected to the processor module, and the output end is connected to the voltage detection module and the cathode of the APD; the adjustable high-voltage module is used to receive the input signal of the processor module to convert the input power into a corresponding voltage and output it to the voltage detection module and the cathode of the APD; the voltage detection module is used to detect the output voltage of the adjustable high-voltage module and send it to the processor module.

[0065] refer to Figure 3 , in an optional embodiment of the present application, the APD working voltage automatic configuration system may also be provided with an input power supply, a temperature detection module and a signal processing module;

[0066] Among them, the input power supply is used to provide power to the system; the temperature detection module is connected to the processor module and is used to detect the ambient temperature of the APD; the processor module can obtain the ambient temperature of the APD through the temperature detection module; the signal processing module is electrically connected to the APD anode and is used to analyze and process the APD gain signal.

[0067] refer to Figure 4 In an optional embodiment of the present application, the APD working voltage automatic configuration system can be as follows Figure 4 The specific circuit implementation shown.

[0068] The input power supply is connected to one end of the inductor L1, and the other end of the inductor L1 is connected to the D pole of the Nmos tube M1 and the anode of the diode D1; the S pole of the Nmos tube M1 is grounded, and the G pole is connected to the PWM output pin of the processor module; the cathode of the diode D1 is connected to the output capacitor C1. The output capacitor C1 is followed by a voltage divider circuit composed of two resistors (R1 and R2), and the divided voltage is connected to the ADC pin of the processor module to detect the average output voltage of the adjustable high-voltage module. The output capacitor C1 is connected to the cathode of the APD through a low-pass filter circuit composed of a filter resistor R3 and a filter capacitor C2.

[0069] When the input signal is high, Nmos is turned on, and the power supply is connected to the ground through the inductor L1 and the Nmos tube M1 to form a loop, and there is current in the inductor; when the input signal is low, the Nmos tube M1 is turned off, the loop is disconnected, and the current on the inductor L1 cannot change suddenly, so a higher induced voltage is generated on the inductor L1, and this voltage is stored in the output capacitor C1 through the diode D1. Repeatedly, a voltage higher than the input power supply can be obtained on the output capacitor C1.

[0070] The processor module can adjust the average output voltage of the adjustable high-voltage module by adjusting the duty cycle of the input signal.

[0071] Among them, the components of the adjustable high-voltage module include inductor L1, diode D1, Nmos tube M1 and output capacitor C1;

[0072] The voltage detection module consists of voltage-dividing resistors R1 and R2. The voltage-dividing voltage is connected to the ADC pin of the processor module. The ADC inside the processor converts the voltage into data. After software averaging filtering, it is multiplied by the corresponding voltage-dividing coefficient to detect the average output voltage.

[0073] In an optional embodiment of the present application, the input power supply can be selected from +5VDC; the inductor L1 can be selected from 100uH; the Nmos tube M1 can be selected from HSS1N20; the diode D1 can be selected from LBAS21HT1G; the output capacitor C1 can be selected from 22nF / 250V; the voltage dividing resistor R1 can be selected from 2.2MΩ, the voltage dividing resistor R2 can be selected from 22KΩ; the filter resistor R3 can be selected from 51KΩ, and the filter capacitor C2 can be selected from 22nF / 250V.

[0074] In an optional embodiment of the present application, the temperature detection module can use an NTC (Negative Temperature Coefficient) resistor and a fixed resistor to form a voltage divider connected to a fixed 3.3V power supply, and the voltage divider voltage is connected to the ADC pin of the processor module. The ADC inside the processor converts the voltage into data. When the ambient temperature changes, the NTC resistor changes, and the corresponding data collected by the ADC also changes. The current temperature is calculated using the formula of NTC resistor and temperature. It should be understood that the specific implementation of the temperature detection module is not limited to the above example, as long as it can be accurately detected.

[0075] In an optional embodiment of the present application, the processor module can generate a PWM signal through a timer and set the PWM duty cycle through software; the processor module can also collect the average output voltage of the adjustable high-voltage module and the temperature data detected by the temperature detection module through ADC. It should be understood that the processor module can select a computing chip with the above processing function, and this embodiment is not limited to using a specific chip.

[0076] In an optional embodiment of the present application, the signal processing module may include an I / V (current-voltage) conversion circuit, a signal amplification circuit, an ADC acquisition circuit, and a data statistics circuit; when the APD receives a light pulse, it will generate a current signal, and the current signal will be converted into a voltage signal through the I / V conversion circuit; the signal amplification circuit will amplify the voltage signal to a suitable value and add a DC bias; the ADC acquisition circuit will sample the analog signal and digitize it to obtain a digital signal; the data statistics circuit will accumulate and save the collected digital signals for analysis and calculation by the processor. It should be understood that the signal processing module can select a computing chip with the above-mentioned processing functions, and this embodiment is not limited to the use of a specific chip.

[0077] refer to Figure 5, is a method for automatically configuring the APD working voltage provided in an embodiment of the present application, the method mainly comprises the following steps: Figure 2 The processor module shown is executed, and the method mainly includes the following steps:

[0078] S501: according to the value of each duty cycle in the set duty cycle interval, the duty cycle of the input signal of the adjustable high-voltage module is set in sequence; and the corresponding average output voltage of the adjustable high-voltage module when the input signal is synchronously detected by the voltage detection module; each input signal with different duty cycles makes the adjustable high-voltage module output an average output voltage; the output end of the adjustable high-voltage module is connected to the cathode of the APD to be configured; the minimum value of each average output voltage is less than 0.5U BR , the maximum value among the average output voltages>U BR , U BR Indicates the calibrated breakdown voltage of the APD to be configured;

[0079] When it is necessary to automatically configure the working voltage of the APD to be configured, the processor module can obtain a preset duty cycle interval, and use the duty cycle values ​​of the set duty cycle interval as input signals in order from small to large, so as to obtain the average output voltage of the adjustable high-voltage module under different input signals. When the output of the adjustable high-voltage module is unloaded, the average output voltage is linearly related to the duty cycle of the input signal. When the adjustable high-voltage module is connected to an APD as a load, it will be affected by the dark current of the APD, causing the input-output relationship to change accordingly. In the absence of ambient light, the relationship between the dark current of the APD and its reverse bias voltage is as follows: Figure 6 As shown; when the reverse bias voltage is low, its dark current is very small, about tens to hundreds of pA, and the load of the adjustable high-voltage module is very small at this time; when the reverse bias voltage becomes larger, the dark current of the APD also increases accordingly, and the load of the adjustable high-voltage module will gradually increase. The input-output relationship of the adjustable high-voltage module is no longer a linear relationship, but is in the same frequency as the dark current change of the APD. Based on this, this embodiment adjusts the duty cycle of the input signal of the adjustable high-voltage module through the processor module, gradually increases the average output voltage of the adjustable high-voltage module (i.e., the reverse bias voltage of the APD), records the input signal duty cycle and the average output voltage, and obtains the corresponding relationship between the input signal duty cycle and the average output voltage.

[0080] In an optional embodiment of the present application, when it is determined that a configuration instruction is received, it indicates that the system needs to automatically configure the working voltage of the APD to be configured; wherein the configuration instruction is used to instruct the automatic configuration of the working voltage of the APD to be configured.

[0081] In an optional embodiment of the present application, the configuration cycle can be set by a timer, for example, once every 1 hour; or the following method can be used to flexibly configure according to actual needs to ensure stable gain and reduce unnecessary configuration processes.

[0082] The processor module obtains the historical ambient temperature corresponding to the APD to be configured when the current working voltage is configured; collects the current ambient temperature of the APD to be configured through the temperature monitoring module; calculates the temperature difference between the current ambient temperature and the historical ambient temperature; if it is determined that the temperature difference is greater than the set temperature difference threshold, it is determined that the configuration instruction is received, indicating that the temperature change is large and the working voltage of the APD needs to be reconfigured; if it is determined that the temperature difference is not greater than the set temperature difference threshold, indicating that the temperature change is not large, the APD to be configured is controlled to maintain the current working voltage and continue to work, and there is no need to adjust the current working voltage of the APD.

[0083] It should be understood that the temperature difference threshold can be flexibly set according to the control accuracy requirements. For example, if the APD gain stability requirements are high, the value of the temperature difference threshold can be set smaller, and the operating voltage can be reconfigured even if the operating temperature changes slightly; for example, it can be set to 0.5 degrees Celsius; if the APD gain stability requirements are not high, the value of the temperature difference threshold can be set larger, for example, it can be set to 3 degrees Celsius.

[0084] In an optional embodiment of the present application, in order to facilitate a more accurate calculation of the turning point voltage later, the duty cycle values ​​in the duty cycle interval should be set as densely as possible (generally not less than 10 duty cycle values, for example, 30-100 can be set) and arranged at equal intervals, and it is necessary to ensure that the average output voltage corresponding to the minimum duty cycle should be less than 0.5 times the breakdown voltage, and the average output voltage corresponding to the maximum duty cycle should be greater than the breakdown voltage, or greater than 1.5 times the breakdown voltage (the current upper limit is 160V), so as to completely cover the APD operating voltage range.

[0085] S502: Calculate the ratio between the duty cycle difference obtained from two consecutive detections and the average output voltage difference (PWM i -PWM i-1 ) / (U i -U i-1 );PWM i Represents the duty cycle of the i-th input signal, PWM i-1 represents the duty cycle of the i-1th input signal, U i represents the ith average output voltage, U i-1 represents the i-1th average output voltage;

[0086] This embodiment calculates the ratio between the duty cycle difference obtained from two consecutive detections and the average output voltage difference, that is, the duty cycle change per volt, to determine the regulation of the input signal duty cycle on the average output voltage, thereby determining the load change.

[0087] S503: Determine whether the ratio is greater than a first preset threshold; if so, go to step S304; if not, go to step S302;

[0088] In an optional embodiment of the present application, the first preset threshold is set in the following manner:

[0089] Calculate the ratio between the duty cycle difference obtained from the first i-1 consecutive detections and the average output voltage difference (PWM j -PWM j-1 ) / (U j -U j-1 ) ;

[0090] The first preset threshold is set to αm1, where α is a set multiple and the value of α is 1.5-2; that is, the first preset threshold is set to 1.5 to 2 times the average value of the ratio calculated from the previous data. When the current ratio is greater than the first preset threshold, it indicates that the duty cycle of the corresponding input signal causes a significant change in the load, so that the corresponding voltage is used as the turning point voltage, and the ideal operating voltage of the APD should be above the turning point voltage.

[0091] It should be understood that if the ratio is not greater than the first preset threshold, it indicates that the current input signal does not cause a significant change in the load compared with the previous data. At this time, the APD dark current is still small. At this time, it is still necessary to continue to increase the input signal duty cycle to increase the average output voltage so that the APD reaches a suitable operating voltage range.

[0092] S504: U i As the first turning point voltage;

[0093] S505: Obtaining the first turning point voltage U i After that, continue to calculate the ratio between the duty cycle difference and the average output voltage difference obtained by the two consecutive detections of the subsequent data (k is greater than i) (PWM k -PWM k-1 ) / (U k -U k-1 );PWM k Indicates the duty cycle of the kth input signal, PWM k-1 represents the duty cycle of the k-1th input signal, U k represents the kth average output voltage, U k-1 represents the k-1th average output voltage; where PWM k Greater than PWM i ;

[0094] S506: Determine whether the ratio is greater than a second preset threshold; if so, go to step S507; if not, go to step S505;

[0095] In an optional embodiment of the present application, the second preset threshold is set in the following manner:

[0096] Calculate the ratio between the duty cycle difference obtained from two consecutive detections from the ith to the k-1th and the average output voltage difference (PWM t - PWM t-1 ) / (U t -U t-1 ) ;

[0097] The second preset threshold is set to βm2, where β is a set multiple and the value of β is 1.5~2.

[0098] That is, the second preset threshold is set to 1.5 to 2 times the average value of the ratio calculated from the previous data (the duty cycle from the i-th to the k-1-th to the average output voltage data). When the current ratio is greater than the second preset threshold, it indicates that the corresponding input signal duty cycle causes a significant change in the load relative to the previous data, so that the corresponding voltage is used as the second turning point voltage; it should be understood that if the ratio is not greater than the second preset threshold, it indicates that the current input signal does not cause a second significant change in the load compared with the previous data, and at this time, it is still necessary to continue to increase the input signal duty cycle to increase the average output voltage so that the APD reaches a suitable operating voltage range; if the ratio is greater than the second preset threshold, it indicates that the current input signal causes a second significant change in the load, and the APD dark current is moderate, which is conducive to the APD maintaining a good balance between the signal-to-noise ratio and the amplification gain. This is the ideal operating voltage range of the APD, and the ideal operating voltage of the APD should be below the second turning point voltage.

[0099] S507: U k as the second turning point voltage;

[0100] S508: Based on the first turning point voltage and the second turning point voltage, calculate and obtain a voltage value required for configuring the APD to be configured; the voltage value required for configuration is greater than the first turning point voltage and less than the second turning point voltage;

[0101] In an optional embodiment of the present application, the average value 1 / 2 (U i +U k ); the average value 1 / 2(U i +U k ) as the voltage value required to be configured for the APD to be configured.

[0102] S509: The voltage value to be configured is used as the working voltage of the APD to be configured, and loaded to the cathode of the APD to be configured, so as to realize automatic configuration of the working voltage of the APD to be configured.

[0103] In an optional embodiment of the present application, based on the one-to-one correspondence between different duty cycles of each input signal and each average output voltage, the average output voltage is used as the horizontal coordinate and the duty cycle is used as the vertical coordinate, and smoothing filtering is performed to establish a relationship diagram between the duty cycle and the output voltage; see Figure 7 As shown;

[0104] It can be seen that there are two turning points. Before the first turning point, the output voltage is low, the dark current of the APD is small, and the system detects that the relationship between the output voltage and the PWM duty cycle is linear; when the output voltage continues to increase, the dark current of the APD also increases accordingly, and the load of the adjustable high-voltage module will gradually increase. When the voltage reaches the first turning point, the proportional relationship between the average output voltage and the duty cycle changes; if the output voltage continues to increase, when the APD reverse bias voltage approaches the breakdown voltage, its dark current will rapidly increase to the uA~mA level, and the load exceeds the load capacity of the adjustable high-voltage module. At this time, the average output voltage obtained by adjusting the input signal duty cycle changes very little, reaching the second turning point.

[0105] The duty cycle of the required configuration corresponding to the required configured voltage value is determined through the relationship diagram, and then the duty cycle of the input signal of the adjustable high-voltage module is controlled to be the duty cycle of the required configuration, so as to realize automatic configuration of the working voltage of the APD to be configured.

[0106] In an optional embodiment of the present application, the processor module collects the average output voltage of the adjustable high-voltage module in real time through the voltage detection module, and records the duty cycle of the input signal at that time, and obtains the above-mentioned Figure 7 Corresponding relationship curve.

[0107] Figure 7 The first turning point and the second turning point included in the corresponding relationship curve themselves change with temperature, so a dynamic detection can be performed according to the current environment to determine the current appropriate working voltage of the APD. Therefore, this solution does not need to know the current specific temperature value and then calculate the working voltage suitable for the APD through a preset working curve; instead, it can directly dynamically detect the input signal and average output voltage curve of the adjustable voltage module under the APD as a load to calculate the most suitable working voltage of the APD, thereby maintaining gain stability. This method effectively reduces the use or production cost of the APD while ensuring the stability of the APD gain.

[0108] In an optional embodiment of the present application, in order to accurately calculate the turning point voltage, the ratio between the duty cycle difference and the average output voltage difference obtained by two adjacent detections is derivate, smoothed and filtered, etc., to reduce the noise caused by measurement errors and interference, and identify the turning point where the data suddenly changes, and obtain the following: Figure 8The relationship curve shown is shown. Through analysis, the voltage values ​​of the first turning point and the second turning point and the corresponding PWM signal values ​​are obtained. Figure 8 The horizontal axis in the middle is the average output voltage, and the vertical axis is the duty cycle difference of the input signal; the gray line is the duty cycle difference pwm2-pwm1 before and after; the yellow line is the curve after smoothing and filtering the gray data.

[0109] This embodiment also provides a processing chip. The processing chip can execute a computer program to implement the relevant steps of the above-mentioned APD working voltage automatic configuration method. For the specific steps, please refer to the above description and will not be repeated here.

[0110] The computer program may be stored in the memory, for example, to implement the instructions of the APD working voltage automatic configuration method provided in the above embodiment; and the data storage area may store the data involved in the APD working voltage automatic configuration method provided in the above embodiment.

[0111] The processing chip may include one or more processing cores. By running or executing instructions, programs, code sets or instruction sets stored in the memory, the data stored in the memory are called to perform various functions and process data of the present application. The processing chip may be at least one of an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a central processing unit (CPU), a controller, a microcontroller and a microprocessor. It is understandable that for different devices, the electronic device for realizing the above-mentioned processor function can also be other, and the embodiments of the present application are not specifically limited.

[0112] The present application embodiment provides a computer-readable storage medium, for example, including: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes. The computer-readable storage medium stores a computer program that can be loaded by a processor and execute the APD working voltage automatic configuration method of the above embodiment.

[0113] An embodiment of the present application also provides a computer program product, which includes a computer program tangibly contained in a readable medium, wherein the computer program includes program code for executing any APD operating voltage automatic configuration method in the embodiments of the present application. The computer program can be downloaded and installed over the network, and / or installed from a removable medium (such as a disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc.).

[0114] As described above, the above embodiments are only used to introduce the technical solution of the present application in detail, but the description of the above embodiments is only used to help understand the method and core idea of ​​the present application and should not be understood as limiting the present application. Any changes or substitutions that can be easily thought of by technicians in this technical field within the technical scope disclosed in the present application should be included in the protection scope of the present application.

Claims

1. A method for automatically configuring an APD operating voltage, characterized in that: include: According to the values ​​of each duty cycle in the set duty cycle interval, the duty cycle of the input signal of the adjustable high-voltage module is set in sequence; The voltage detection module is used to synchronously detect the average output voltage corresponding to the input signal of the adjustable high-voltage module; each input signal with a different duty cycle causes the adjustable high-voltage module to output an average output voltage; the output end of the adjustable high-voltage module is connected to the cathode of the APD to be configured; Calculate the ratio between the duty cycle difference and the average output voltage difference obtained by two consecutive detections (PWM i -PWM i-1 ) / (U i -U i-1 );PWM i Represents the duty cycle of the i-th input signal, PWM i-1 represents the duty cycle of the i-1th input signal, U i represents the ith average output voltage, U i-1 represents the i-1th average output voltage; Determining whether the ratio is greater than a first preset threshold; If so, then U i As the first turning point voltage; The first turning point voltage U i After that, the ratio between the duty cycle difference and the average output voltage difference obtained by two consecutive detections is calculated (PWM k -PWM k-1 ) / (U k -U k-1 );PWM k Indicates the duty cycle of the kth input signal, PWM k-1 represents the duty cycle of the k-1th input signal, U k represents the kth average output voltage, U k-1 represents the k-1th average output voltage; where PWM k Greater than PWM i ; Determining whether the ratio is greater than a second preset threshold; If so, then U k as the second turning point voltage; Based on the first turning point voltage and the second turning point voltage, a voltage value required to be configured of the APD to be configured is calculated; the voltage value required to be configured is greater than the first turning point voltage and less than the second turning point voltage; The voltage value required to be configured is used as the working voltage of the APD to be configured and loaded to the cathode of the APD to be configured, so as to realize automatic configuration of the working voltage of the APD to be configured.

2. The APD working voltage automatic configuration method according to claim 1, characterized in that: The duty cycle values ​​in the set duty cycle interval are arranged at equal intervals.

3. The APD working voltage automatic configuration method according to claim 1, characterized in that: The first preset threshold is set in the following manner: Calculate the average value m1 of the ratio between the duty cycle difference and the average output voltage difference obtained from the first i-1 consecutive detections; The first preset threshold is set to αm1, where α is a set multiple and has a value of 1.5 to 2.

4. The APD working voltage automatic configuration method according to claim 1, characterized in that: The second preset threshold is set in the following manner: Calculate the average value m2 of the ratio between the duty cycle difference and the average output voltage difference obtained from two adjacent detections from the ith to the k-1th; The second preset threshold is set to βm1, where β is a set multiple and has a value of 1.5 to 2.

5. The APD working voltage automatic configuration method according to claim 1, characterized in that: The step of calculating the voltage value required to be configured by the APD to be configured based on the first turning point voltage and the second turning point voltage includes: Calculating an average value of the first turning point voltage and the second turning point voltage; The average value is used as the voltage value required to be configured for the APD to be configured.

6. The APD working voltage automatic configuration method according to claim 1, characterized in that: The APD working voltage automatic configuration method further includes: Based on the one-to-one correspondence between different duty cycles of each input signal and each average output voltage, the average output voltage is used as the horizontal coordinate and the duty cycle is used as the vertical coordinate, and smoothing filtering is performed to establish a relationship diagram between the duty cycle and the output voltage; The duty cycle of the required configuration corresponding to the required configured voltage value is determined through the relationship diagram, and then the duty cycle of the input signal of the adjustable high-voltage module is controlled to be the duty cycle of the required configuration, so as to realize automatic configuration of the working voltage of the APD to be configured.

7. The APD working voltage automatic configuration method according to claim 1, characterized in that: Before sequentially setting the duty cycle of the input signal of the adjustable high-voltage module according to the value of each duty cycle in the set duty cycle interval, the method further includes: It is determined that a configuration instruction is received; the configuration instruction is used to instruct automatic configuration of the operating voltage of the APD to be configured.

8. The APD working voltage automatic configuration method according to claim 7, characterized in that: The determining that a configuration instruction is received comprises: Obtaining the historical ambient temperature corresponding to the APD to be configured when configuring the current operating voltage; Collecting the current ambient temperature of the APD to be configured through a temperature monitoring module; Calculating the temperature difference between the current ambient temperature and the historical ambient temperature; If it is determined that the temperature difference is greater than the set temperature difference threshold, it is determined that the configuration instruction has been received; if it is determined that the temperature difference is not greater than the set temperature difference threshold, the APD to be configured is controlled to maintain the current operating voltage and continue to operate.

9. An APD working voltage automatic configuration system, characterized in that: It includes an adjustable high voltage module, a processor module, a voltage detection module and an APD; The input end of the adjustable high voltage module is connected to the processor module, and the output end of the adjustable high voltage module is connected to the voltage detection module and the cathode of the APD; the adjustable high voltage module is used to receive the input signal of the processor module to convert the input power into a corresponding voltage and output it to the voltage detection module and the cathode of the APD; The voltage detection module is used to detect the output voltage of the adjustable high-voltage module and send it to the processor module; The processor module is used to implement the APD working voltage automatic configuration method described in any one of claims 1 to 8.

10. A processing chip, characterized in that: The processing chip can execute a computer program to implement the APD working voltage automatic configuration method as described in any one of claims 1-8.

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