High-voltage power supply circuit of APD detector and closed-loop control method

Abstract

The invention provides a high-voltage power supply circuit of an APD detector and a closed-loop control method, and belongs to the technical field of photoelectric detectors, and the high-voltage power supply circuit comprises a high-voltage output circuit, a high-voltage conditioning circuit, a temperature sensor, a temperature sensor output conditioning circuit, a digital potentiometer and an SoC processor. The SoC processor adjusts the resistance value of the digital potentiometer according to the relation between the actual power supply high voltage and the target high voltage, so that the high-voltage power supply circuit outputs normally. According to the high-voltage power supply circuit, discrete components are used for forming the high-voltage circuit to replace a customized power supply module, and the problem that an existing high-voltage power supply circuit is high in cost is solved; and the influence of the temperature on the APD detector is overcome by a closed-loop control method of self-correction of the high-voltage output circuit, the temperature sensor and the SoC processor, so that automatic and accurate output of the power supply high voltage is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of photodetectors, and more specifically, relates to a high-voltage power supply circuit and a closed-loop control method for an APD detector. Background Art

[0002] Quadrant detectors are widely used in fields such as laser collimation, laser alignment, laser guidance, laser guidance, laser warning, laser reconnaissance, and laser automatic tracking due to their advantages such as a high spectral response range, high positioning accuracy, and fast resolution speed. According to the different materials of the devices, quadrant detectors are usually divided into PIN quadrant detectors and APD avalanche quadrant detectors (hereinafter referred to as "APD detectors"). The PIN quadrant detector is characterized by low power consumption, small size, low noise, and a small required supply voltage; the responsivity is relatively low, generally less than 1 A / W. In order to obtain a sufficiently large electrical signal, an amplifier circuit needs to be designed to obtain a sufficient dynamic range; it is mainly applied to occasions with a large echo power and low requirements for reception sensitivity and response time. The APD detector is a new type of high-sensitivity photodetection and sensor device. It generates an avalanche multiplication effect by means of the action of a strong internal electric field, and its responsivity can often reach dozens of A / W, which makes it different from other detection devices. It has the characteristics of small size, light weight, low power consumption, high sensitivity, fast response speed, and high reliability.

[0003] Due to the avalanche characteristics of the APD detector, it is particularly sensitive to the operating temperature. When the temperature rises, the breakdown voltage increases, and when the temperature drops, the breakdown voltage decreases. The stability of the detector output plays a crucial role in the detection accuracy of the entire machine system. If the ambient temperature changes during the operation of the device, the breakdown voltage will also change accordingly, resulting in fluctuations in the output gain of the device, affecting its gain stability, and thus having an adverse effect on system detection. Especially under low-temperature conditions, when the echo signal is weak, the initial gain point is set relatively high, and the gain curve is steep. At this time, the stability of the system is most affected by temperature.

[0004] The breakdown voltage range of the APD detector within its operating temperature range is relatively wide, from 100 V to 600 V. If the supply voltage of the APD detector is not adjusted according to the operating ambient temperature, it is very easy to cause breakdown and damage the device; at the same time, in order to meet the required dynamic gain range and dynamic gain adjustment of the system, the supply voltage must be at an appropriate voltage during operation. Therefore, closed-loop control is required during its operation.

[0005] Usually, when designing the scheme, only the closed-loop control of the supply voltage and the operating ambient temperature is carried out, but there is a lack of system self-calibration, and it is impossible to determine whether the supply voltage output is correct; moreover, the supply voltage of the APD detector is mostly provided by a customized high-voltage power supply module, resulting in a high cost. Summary of the Invention

[0006] The object of the present invention is to provide a high-voltage power supply circuit and a closed-loop control method for an APD detector. The high-voltage power supply circuit of the APD detector of the present invention uses discrete components to form a high-voltage power supply circuit to replace a customized power module, so as to solve the problem of high cost of the existing high-voltage power supply circuit; and uses a closed-loop control method of temperature and self-calibration to overcome the influence of temperature on the APD detector, and realizes automatic adjustment and accurate output of the supplied high voltage.

[0007] To achieve the above object, in the first aspect of the present invention, a high-voltage power supply circuit for an APD detector is provided, including: a high-voltage output circuit, a high-voltage conditioning circuit, a temperature sensor, a temperature sensor output conditioning circuit, a digital potentiometer, and an SoC processor;

[0008] The high-voltage output circuit is used to input high voltage to the APD detector;

[0009] The high-voltage conditioning circuit is electrically connected to the output end of the high-voltage output circuit, and is used to obtain a first input voltage suitable for the internal XADC of the SoC processor after voltage division of the high voltage output by the high-voltage output circuit through a resistor;

[0010] The temperature sensor is used to detect the operating temperature of the APD detector, and the temperature sensor output conditioning circuit is electrically connected to the temperature sensor and the SoC processor; the temperature sensor output conditioning circuit is used to convert the voltage output by the temperature sensor into a second input voltage suitable for the internal XADC of the SoC processor;

[0011] One end of the digital potentiometer is electrically connected to the high-voltage output circuit, and the other end is electrically connected to the SoC processor;

[0012] The SoC processor calculates the actual supplied high voltage of the high-voltage output circuit according to the received first input voltage, the SoC processor adjusts the resistance value of the digital potentiometer according to the received second input voltage and outputs the target high voltage of the high-voltage output circuit, and the SoC processor adjusts the resistance value of the digital potentiometer according to the relationship between the actual supplied high voltage and the target high voltage so that the high-voltage power supply circuit outputs normally.

[0013] Further, the condition for the normal output of the high-voltage power supply circuit is: the actual supplied high voltage = the target high voltage ± 3V.

[0014] Further, the high-voltage output circuit includes a flyback boost controller, a transformer, an N-channel MOS transistor, a first protection diode, and related configured resistor-capacitor components. One pin of the flyback boost controller is electrically connected between a first feedback resistor and a second feedback resistor. The first feedback resistor is electrically connected to the output terminal VHV of the high-voltage output circuit and the cathode of the first protection diode. One of the first feedback resistor and the second feedback resistor is electrically connected to the SoC processor and serves as the digital potentiometer, and one end of the second feedback resistor is connected to AGND.

[0015] Further, the first feedback resistor is R FBH and the second feedback resistor is R FBL . The second feedback resistor is electrically connected to the SoC processor, and the resistance value of the second feedback resistor is calculated according to the following formula:

[0016]

[0017] where V OUT is the actual power supply high voltage or the target high voltage of the high-voltage output circuit.

[0018] Further, the related configured resistor-capacitor components include:

[0019] A first resistor group connected in parallel between the low-voltage VCC and the flyback boost controller: R1, R4, R5, R7, R9, R10, R12,

[0020] An electrolytic capacitor C1, one end of which is electrically connected between the first resistor group and the low-voltage VCC, and the other end is connected to AGND;

[0021] A second resistor group connected in parallel between the flyback boost controller and the first end of the transformer: R2, R3. The second end of the transformer is electrically connected to the low-voltage VCC. The third end of the transformer is connected to the anode of the first protection diode, and the cathode of the first protection diode is connected to the output terminal VHV of the high-voltage output circuit; the fourth end of the transformer is connected to AGND;

[0022] A resistor R6, one end of which is connected to the source of the N-channel MOS transistor and one pin of the flyback boost controller, and the other end is connected to AGND; the drain of the N-channel MOS transistor is electrically connected to one end of the second resistor group and the first end of the transformer, and the gate of the N-channel MOS transistor is connected to one pin of the flyback boost controller;

[0023] A resistor R13, both ends of which are respectively connected to two pins of the flyback boost controller, and one end is connected to AGND; and,

[0024] A ceramic capacitor C2 and an electrolytic capacitor C3 are connected in parallel between the cathode of the first protection diode and the output terminal VHV of the high-voltage output circuit. The other ends of the ceramic capacitor C2 and the electrolytic capacitor C3 are both connected to AGND.

[0025] Further, the model of the flyback boost controller is LT3751, the model of the transformer is DA2032-AL, the model of the N-channel MOS transistor is IRFP4668, the model of the first protection diode is MUR460, and the resistance value of the first feedback resistor R FBH is 274 KΩ, the model of the second feedback resistor R FBL is TPL040A-10, and the remaining resistor and capacitor components are configured according to the general configuration of the LT3751 data sheet.

[0026] Further, the ranges of the first input voltage and the second input voltage are 0 - 1V.

[0027] Further, the model of the SoC processor is FMQL20S484.

[0028] Further, the model of the temperature sensor is TMP20.

[0029] Further, the high-voltage conditioning circuit includes resistors R20, R21, and a second protection diode. One end of the resistor R20 is connected to the output terminal VHV of the high-voltage output circuit, and the other end is connected to the analog input interface of the XADC inside the SoC processor. A resistor R21 and the second protection diode are connected in parallel between the other end of the resistor R20 and the analog input interface of the XADC inside the SoC processor. The anode of the second protection diode and the other end of the resistor R21 are both connected to AGND.

[0030] Further, the temperature sensor output conditioning circuit includes a precision operational amplifier, resistors R14, R15, R16, R17, R18, R19, and capacitors C4, C5, C6, C7. The first pin and the seventh pin of the precision operational amplifier are electrically connected to the analog input interface of the internal XADC of the SoC processor. The second pin and the sixth pin of the precision operational amplifier are respectively connected to the temperature sensor through resistor R15 and resistor R18. Resistor R14 is connected between the first pin and the second pin of the precision operational amplifier. Resistor R16 is connected between the sixth pin and the seventh pin of the precision operational amplifier. The fourth pin of the precision operational amplifier is connected to -5VA. One end of capacitors C6 and C7 is connected in parallel to the fourth pin of the precision operational amplifier and the other end is connected to AGND. The eighth pin of the precision operational amplifier is connected to +5VA. One end of capacitors C4 and C5 is connected in parallel to the eighth pin of the precision operational amplifier and the other end is connected to AGND. One end of resistor R19 is connected to the fifth pin of the precision operational amplifier and the other end is connected to AGND.

[0031] In the second aspect of the present invention, a closed-loop control method for the high-voltage power supply circuit of an APD detector is provided, including the following steps:

[0032] Step 1: The high-voltage power supply circuit of the APD detector performs a power-on self-check, and the SoC processor initializes and configures the initial resistance value R of the digital potentiometer. FBL0 The high-voltage output circuit outputs an initial voltage VHV0.

[0033] Step 2: The SoC processor collects and calculates the working environment temperature of the APD detector as the normal temperature T. 0 The SoC processor looks up the table to obtain the high-voltage value corresponding to the best responsivity at the corresponding T temperature, and calculates the resistance value R that the digital potentiometer should output. 0 Thus, the high-voltage output circuit outputs the target high-voltage value VHV1. FBL1

[0034] Step 3: At the same time, the SoC processor collects and calculates through the high-voltage conditioning circuit to obtain the high-voltage value VHV2 of the actual high-voltage output circuit of the APD detector. At this time, the corresponding resistance value of the digital potentiometer is R. FBL2 If VHV2 = VHV1 ± 3V, the high-voltage power supply circuit outputs normally; otherwise, the SoC processor needs to continue to configure the digital potentiometer to close-loop regulate the output of the high-voltage output circuit until the condition of VHV2 = VHV1 ± 3V is met.

[0035] Step 4: When the working temperature of the APD quadrant detector changes, such as when it is stable at T. 1 If T. 1 > T. 0, then the high voltage for the best responsivity of the APD quadrant detector is VHV3 = VHV1 + (T1 - T0) × δ; if T 1 <T 0 When it is, then the high voltage for the best responsivity of the APD detector is VHV3 = VHV1 + (T0 - T1) × δ, where δ is the temperature coefficient of the high voltage supply of the APD detector; then the SoC processor calculates the resistance value R of the digital potentiometer corresponding to the target high voltage FBL3 and configures the output; the high voltage output circuit outputs the target high voltage value VHV3; the SoC processor calibrates the target high voltage VHV3 according to step 3 through the high voltage conditioning circuit.

[0036] Compared with the prior art, the present invention has the following technical effects:

[0037] The high voltage supply circuit of an APD detector of the present invention uses discrete components to form a high voltage output circuit to replace the custom power module, solving the problem of high cost of the existing high voltage supply circuit; and uses a closed-loop control method of self-calibration of the high voltage output circuit, temperature sensor and SoC processor to overcome the influence of temperature on the APD detector, realizing automatic and accurate output of the supply high voltage.

[0038] The closed-loop control method of the high voltage supply circuit of an APD detector of the present invention uses a closed-loop control method of self-calibration of the high voltage output circuit, temperature sensor and SoC processor to overcome the influence of temperature on the APD detector, realizing automatic and accurate output of the supply high voltage. Description of the Drawings

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0040] Figure 1 It is a closed-loop control block diagram of a high voltage supply circuit of an APD detector provided by an embodiment of the present invention;

[0041] Figure 2 It is a circuit diagram of the connection between a high voltage output circuit and a digital potentiometer provided by an embodiment of the present invention;

[0042] Figure 3 It is a circuit diagram of a high voltage conditioning circuit provided by an embodiment of the present invention;

[0043] Figure 4 It is a circuit diagram of a temperature sensor output conditioning circuit provided by an embodiment of the present invention. Detailed Embodiments

[0044] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] In the present invention, the term "and / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. Wherein A and B may be singular or plural. The character " / " generally represents an "or" relationship between the front and rear associated objects.

[0046] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "said" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0047] The terms "first" and "second" are only used for descriptive purposes to distinguish objects such as substances from each other, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. For example, without departing from the scope of the embodiments of the present invention, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0048] The embodiment of the present invention provides a high-voltage power supply circuit for a low-cost APD detector, and its circuit structure is as Figures 1-4 shown, including: a high-voltage output circuit, a high-voltage conditioning circuit, a temperature sensor, a temperature sensor output conditioning circuit, a digital potentiometer and an SoC processor.

[0049] Among them, the high-voltage output circuit is used to input high-voltage electricity to the APD detector.

[0050] The high-voltage conditioning circuit is electrically connected to the output terminal VHV of the high-voltage output circuit, and is used to obtain a first input voltage suitable for the internal XADC (i.e., analog-to-digital converter) of the SoC processor after dividing the high voltage VHV output by the high-voltage output circuit through a resistor. This first input voltage is generally 0-1V.

[0051] The temperature sensor is used to detect the operating temperature of the APD detector. In order to accurately measure the operating environment temperature of the APD detector, the temperature sensor needs to be placed close to the metal housing of the APD detector. The temperature sensor in the embodiment of the present invention is a high-precision analog temperature sensor, and a chip with the model TMP20 produced by TI Company can be selected. This chip is a temperature sensor with a low operating voltage and direct precision calibration for Celsius temperature. Its output voltage has a linear proportional relationship with the Celsius temperature of the environment where the device is located. The reference accuracy of this device within the full temperature range (-55°C to 130°C) is ±2.5°C, the proportional coefficient is -11.77 mV / °C, the output voltage at 0°C is 1.8639 V, and the linearity of the output within the temperature range of -40°C to 85°C is ±0.65°C.

[0052] The output conditioning circuit of the temperature sensor is electrically connected to the temperature sensor and the SoC processor; the output conditioning circuit of the temperature sensor is used to convert the voltage output by the temperature sensor into a second input voltage suitable for the internal XADC of the SoC processor, and this second input voltage is generally 0 - 1V.

[0053] One end of the digital potentiometer is electrically connected to the high-voltage output circuit, and the other end is electrically connected to the SoC processor.

[0054] The SoC processor calculates the actual power supply high voltage of the high-voltage output circuit according to the received first input voltage, the SoC processor adjusts the resistance value of the digital potentiometer according to the received second input voltage and outputs the target high voltage of the high-voltage output circuit, and the SoC processor adjusts the resistance value of the digital potentiometer according to the relationship between the actual power supply high voltage and the target high voltage to make the high-voltage power supply circuit output normally. Specifically, the SoC processor samples the voltage signal output by the temperature sensor and the self-calibration feedback voltage of the high-voltage output circuit through the internal analog-to-digital converter (XADC), and calculates the feedback resistance R corresponding to the high voltage required by the current APD detector. FBL The above functions are only part of the functions implemented by the SoC processor. The SoC processor consists of two parts: a processor system (PS) and a programmable logic (PL). Its PS part is a quad-core high-performance ARM processor with a single-core operating frequency of 866 MHz; the PL part is an A7 series FPGA.

[0055] In the embodiment of the present invention, the condition for the high-voltage power supply circuit to output normally is: actual power supply high voltage = target high voltage ± 3V.

[0056] The high-voltage power supply circuit in the embodiment of the present invention converts the low-voltage VCC into the high voltage required for the operation of the APD detector through a temperature and self-calibration feedback closed loop.

[0057] An embodiment of the present invention designs a photoelectric signal processing circuit for converting single - ended input to differential output at the backend of the output of a photodetector, and makes precise impedance matching analysis and calculation. As Figure 2 shown, the high - voltage output circuit of the embodiment of the present invention includes a flyback boost controller N1, a transformer T1, an N - channel MOS transistor Q1, a first protection diode D1, and related configured resistor - capacitor components. The tenth pin of the flyback boost controller N1 is electrically connected between a first feedback resistor R8 and a second feedback resistor R11. The first feedback resistor R8 is electrically connected to the output terminal VHV of the high - voltage output circuit and the cathode of the first protection diode D1. One of the first feedback resistor R8 and the second feedback resistor R11 is electrically connected to the SoC processor and serves as a digital potentiometer. One end of the second feedback resistor R11 is connected to AGND. In the figure, VCC is the input voltage of the high - voltage output circuit. The high - voltage output circuit of the embodiment of the present invention is composed of discrete components, and its procurement cost is 30% of that of a customized high - voltage power module, effectively reducing the overall machine cost.

[0058] The flyback boost controller N1 of the embodiment of the present invention uses the turns ratio of the transformer T1 and external resistors (the first feedback resistor R8, the second feedback resistor R11) to achieve the output of the target high voltage, and can calculate according to the temperature information fed back by the temperature sensor and the feedback information of the current detector supply voltage value, and adjust the required different high - voltage values by adjusting the resistance value of one of the external resistors (the first feedback resistor R8 or the second feedback resistor R11).

[0059] In the embodiment of the present invention, the first feedback resistor R8 is denoted as R FBH , and its type is selected according to the recommended value in the data sheet of the flyback boost controller N1. The second feedback resistor R11 is denoted as R FBL . The second feedback resistor R11 is electrically connected to the SoC processor, that is, the second feedback resistor R11 serves as a digital potentiometer. The resistance value of the second feedback resistor R11 is calculated according to the following formula:

[0060]

[0061] Among them, V OUT is the actual supply high voltage or target high voltage of the high - voltage output circuit.

[0062] It is known that the resistance value of R FBH is 274 KΩ (0.5 W). When V OUT1 = 300 V, the resistance value of R FBL is 1.13 KΩ; when V OUT2 = 240 V, the resistance value of R FBL is 1.4 KΩ; when V OUT3 = 180 V, the resistance value of R FBL is 1.87 KΩ; when V OUT4When = 120V, R FBL has a resistance value of 2.8 KΩ; V OUT5 When = 60V, R FBL has a resistance value of 5.7 KΩ; V OUT6 When = 20V, R FBL has a resistance value of 17.8 KΩ.

[0063] The digital potentiometer R of the embodiment of the present invention FBL is of the model TPL040A - 10, and its required resistance value can be adjusted by the SoC processor to achieve closed - loop automatic variable adjustment of high - voltage output. The model of the SoC processor is FMQL20S484.

[0064] Furthermore, the relevant configured resistor - capacitor components in the high - voltage output circuit of the embodiment of the present invention include:

[0065] The first resistor group connected in parallel between the low - voltage VCC and the first to seventh pins of the flyback boost controller N1: R1, R4, R5, R7, R9, R10, R12,

[0066] The electrolytic capacitor C1, one end of which is electrically connected between the first resistor group and the low - voltage VCC, and the other end is connected to AGND;

[0067] The second resistor group connected in parallel between the eighteenth and twentieth pins of the flyback boost controller N1 and the first end of the transformer T1: R2, R3. The second end of the transformer T1 is electrically connected to the low - voltage VCC, the third end of the transformer T1 is connected to the anode of the first protection diode D1, and the cathode of the first protection diode D1 is connected to the output terminal VHV of the high - voltage output circuit; the fourth end of the transformer T1 is connected to AGND;

[0068] The resistor R6, one end of which is connected to the source of the N - channel MOS transistor Q1 and the twelfth pin of the flyback boost controller N1, and the other end is connected to AGND; the drain of the N - channel MOS transistor Q1 is electrically connected to one end of the second resistor group and the first end of the transformer T1, and the gate of the N - channel MOS transistor Q1 is connected to the fifteenth pin of the flyback boost controller N1;

[0069] The resistor R13, both ends of which are respectively connected to the sixteenth and eleventh pins of the flyback boost controller N1, and one end is connected to AGND;

[0070] The ceramic capacitor C2 and the electrolytic capacitor C3 connected in parallel between the cathode of the first protection diode D1 and the output terminal VHV of the high - voltage output circuit. The other ends of the ceramic capacitor C2 and the electrolytic capacitor C3 are both connected to AGND.

[0071] Capacitors C1 and C3 are electrolytic capacitors, which function as energy storage and filtering; capacitor C2 is a ceramic capacitor, which functions as high-frequency filtering. In addition, the eighth, thirteenth, and fourteenth pins of the flyback boost controller N1 are connected to the low-voltage VCC, and the ninth pin is connected to AGND.

[0072] Specifically, in the high-voltage output circuit of the embodiment of the present invention, the model of the flyback boost controller N1 is LT3751, the model of the transformer T1 is DA2032-AL, the model of the N-channel MOS transistor Q1 is IRFP4668, and the model of the first protection diode D1 is MUR460. The relevant configured resistor and capacitor components are configured according to the LT3751 data sheet: R1 = 40.2 KΩ, R2 = R3 = 18.2 KΩ, R4 = R7 = 69.8 KΩ, R5 = R9 = 475 KΩ, R6 = 6 mΩ, R10 = R12 = 100 KΩ, R13 = 1.1 KΩ, C1 = 680 uF, C2 = 0.1 uF, C3 = 100 uF.

[0073] Further, as Figure 3 shown, the high-voltage conditioning circuit of the embodiment of the present invention includes resistors R20, R21 and a second protection diode D3. One end of the resistor R20 is connected to the output terminal VHV of the high-voltage output circuit, and the other end is connected to the analog input interface of the XADC inside the SoC processor. A resistor R21 and a second protection diode D3 are connected in parallel between the other end of the resistor R20 and the analog input interface of the XADC inside the SoC processor. The anode of the second protection diode D3 and the other end of the resistor R21 are both connected to AGND. Specifically, R20 = 10 MΩ, R21 = 27.4 KΩ. Through the high-voltage conditioning circuit of the embodiment of the present invention, the high voltage VHV output by the high-voltage output circuit is divided by the resistors R20 and R21 to obtain an input voltage range (0 - 1V) suitable for the XADC inside the SoC processor, and then is clamped by the second protection diode D3 and sent to the analog input interface of the XADC inside the SoC processor, and the actual supply voltage of the APD detector output by the high-voltage output circuit is obtained through sampling and calculation.

[0074] Further, as Figure 4As shown, the temperature sensor output conditioning circuit of the embodiment of the present invention includes a precision operational amplifier D2, resistors R14, R15, R16, R17, R18, R19, and capacitors C4, C5, C6, and C7; the first pin and the seventh pin of the precision operational amplifier D2 are electrically connected to the analog input interface of the XADC inside the SoC processor, the second pin and the sixth pin of the precision operational amplifier D2 are electrically connected to the temperature sensor through the resistor R15 and the resistor R18 respectively, the resistor R14 is connected between the first pin and the second pin of the precision operational amplifier D2, the resistor R16 is connected between the sixth pin and the seventh pin of the precision operational amplifier D2, the fourth pin of the precision operational amplifier D2 is connected to -5VA, one end of the capacitors C6 and C7 are connected in parallel to the fourth pin of the precision operational amplifier D2 and the other end is connected to AGND, the eighth pin of the precision operational amplifier D2 is connected to +5VA, one end of the capacitors C4 and C5 are connected in parallel to the eighth pin of the precision operational amplifier D2 and the other end is connected to AGND, and one end of the resistor R19 is connected to the fifth pin of the precision operational amplifier D2 and the other end is connected to AGND. Specifically, the model of the precision operational amplifier D2 of the embodiment of the present invention is OPA2177, R14=4.01KΩ, R15=R16=R17=R18=R19=10KΩ, C4=C7=0.1uF, C5=C6=4.7uF. The temperature sensor output conditioning circuit of the embodiment of the present invention converts the voltage output by the temperature sensor (voltage range 0.8639V-2.3347V (corresponding to temperature -40℃-85℃)) into the voltage range (0-1V) matching the XADC inside the SoC processor after being attenuated 2.5 times by the precision operational amplifier D2, and then sent to the XADC inside the SoC processor for sampling.

[0075] The embodiment of the present invention further provides a closed-loop control method for a high-voltage power supply circuit of an APD detector, comprising the following steps:

[0076] Step 1: The APD detector high voltage power supply circuit performs a power-on self-test and the SoC processor initializes and configures the initial resistance value R of the digital potentiometer FBL0 , the high voltage output circuit outputs an initial voltage VHV0;

[0077] Step 2: The SoC processor collects and solves the working environment temperature of the APD detector as normal temperature T 0 , the SoC processor looks up the table to get the corresponding T 0 The high voltage value V corresponding to the best response at the temperature OUT , and calculate the resistance value R that the digital potentiometer should output according to formula 1 FBL1 , so that the high voltage output circuit outputs the target high voltage value VHV1;

[0078] Step 3: Meanwhile, the SoC processor acquires and calculates the high voltage value VHV2 of the actual high voltage output circuit of the APD detector through the high voltage conditioning circuit. At this time, the resistance value of the corresponding digital potentiometer is R FBL2 ; if VHV2 = VHV1 ± 3V, the high voltage power supply circuit outputs normally; otherwise, the SoC processor needs to continue to configure the digital potentiometer to close-loop regulate the output of the high voltage output circuit until the condition of VHV2 = VHV1 ± 3V is met;

[0079] Step 4: When the operating temperature of the APD quadrant detector changes, such as when it is stable at T 1 When, if T 1 >T 0 , the high voltage of the best responsivity of the APD quadrant detector is VHV3 = VHV1 + (T1 - T0) × δ; if T 1 <T 0 When, the high voltage of the best responsivity of the APD detector is VHV3 = VHV1 + (T0 - T1) × δ, where δ is the high voltage supply temperature coefficient of the APD detector, generally δ = 3.3V / K; then the SoC processor calculates the resistance value R FBL3 of the digital potentiometer corresponding to the target high voltage and configures the output; the high voltage output circuit outputs the target high voltage value VHV3; the SoC processor calibrates the target high voltage VHV3 according to Step 3 through the high voltage conditioning circuit.

[0080] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A high voltage power supply circuit for an APD detector, characterized in that: include: High voltage output circuit, high voltage conditioning circuit, temperature sensor, temperature sensor output conditioning circuit, digital potentiometer and SoC processor; The high voltage output circuit is used to input high voltage electricity to the APD detector; The high-voltage conditioning circuit is electrically connected to the output end of the high-voltage output circuit, and is used to obtain a first input voltage suitable for the XADC inside the SoC processor by dividing the high voltage output by the high-voltage output circuit through resistors; The temperature sensor is used to detect the operating temperature of the APD detector, and the temperature sensor output conditioning circuit is electrically connected to the temperature sensor and the SoC processor; the temperature sensor output conditioning circuit is used to convert the voltage output by the temperature sensor into a second input voltage suitable for the XADC inside the SoC processor; One end of the digital potentiometer is electrically connected to the high voltage output circuit, and the other end is electrically connected to the SoC processor; The SoC processor calculates the actual power supply high voltage of the high-voltage output circuit based on the first input voltage received, the SoC processor adjusts the resistance value of the digital potentiometer based on the second input voltage received and outputs the target high voltage of the high-voltage output circuit, and the SoC processor adjusts the resistance value of the digital potentiometer based on the relationship between the actual power supply high voltage and the target high voltage so that the high-voltage power supply circuit outputs normally.

2. A high voltage power supply circuit for an APD detector as claimed in claim 1, characterized in that: The condition for the high-voltage power supply circuit to output normally is: the actual power supply high voltage = the target high voltage ±3V.

3. A high voltage power supply circuit for an APD detector as claimed in claim 1, characterized in that: The high-voltage output circuit includes a flyback boost controller, a transformer, an N-channel MOS transistor, a first protection diode and related configured resistor and capacitor devices. A pin of the flyback boost controller is electrically connected between a first feedback resistor and a second feedback resistor. The first feedback resistor is electrically connected to the output end of the high-voltage output circuit and the cathode of the first protection diode. One of the first feedback resistor and the second feedback resistor is electrically connected to the SoC processor and serves as the digital potentiometer. One end of the second feedback resistor is connected to AGND.

4. A high voltage power supply circuit for an APD detector as claimed in claim 3, characterized in that: The first feedback resistor is R FBH The second feedback resistor is R FBL , the second feedback resistor is electrically connected to the SoC processor, and the resistance value of the second feedback resistor is calculated according to the following formula: Among them, V OUT It is the actual power supply high voltage or the target high voltage of the high voltage output circuit.

5. The high voltage power supply circuit of an APD detector as claimed in claim 3, characterized in that: The related configuration resistor and capacitor device includes: A first resistor group connected in parallel between the low voltage VCC and the flyback boost controller: R1, R4, R5, R7, R9, R10, R12, An electrolytic capacitor C1, one end of which is electrically connected between the first resistor group and the low voltage VCC, and the other end of which is connected to AGND; A second resistor group R2 and R3 connected in parallel between the flyback boost controller and the first end of the transformer, the second end of the transformer is electrically connected to the low voltage VCC, the third end of the transformer is connected to the anode of the first protection diode, and the cathode of the first protection diode is connected to the output end of the high voltage output circuit; the fourth end of the transformer is connected to AGND; A resistor R6, one end of which is connected to the source of the N-channel MOS tube and a pin of the flyback boost controller, and the other end is connected to AGND; the drain of the N-channel MOS tube is electrically connected to one end of the second resistor group and the first end of the transformer, and the gate of the N-channel MOS tube is connected to a pin of the flyback boost controller; a resistor R13, two ends of which are respectively connected to two pins of the flyback boost controller, and one end of which is connected to AGND; and, A ceramic capacitor C2 and an electrolytic capacitor C3 are connected in parallel between the cathode of the first protection diode and the output end of the high-voltage output circuit, and the other ends of the ceramic capacitor C2 and the electrolytic capacitor C3 are both connected to AGND.

6. A high voltage power supply circuit for an APD detector as claimed in claim 4, characterized in that: The model of the flyback boost controller is LT3751, the model of the transformer is DA2032-AL, the model of the N-channel MOS tube is IRFP4668, the model of the first protection diode is MUR460, and the model of the first feedback resistor R FBH The resistance of the second feedback resistor R FBL The model number is TPL040A-10, and the other resistors and capacitors are configured as per the LT3751 data sheet.

7. The high voltage power supply circuit of an APD detector according to claim 1, characterized in that: The first input voltage and the second input voltage are in the range of 0-1V; and / or, The SoC processor model is FMQL20S484; and / or, The temperature sensor model is TMP20.

8. The high voltage power supply circuit of an APD detector according to claim 1, characterized in that: The high-voltage conditioning circuit includes resistors R20, R21, and a second protection diode. One end of the resistor R20 is connected to the output end of the high-voltage output circuit, and the other end is connected to the analog input interface of the XADC inside the SoC processor. A resistor R21 and the second protection diode are connected in parallel between the other end of the resistor R20 and the analog input interface of the XADC inside the SoC processor. The anode of the second protection diode and the other end of the resistor R21 are both connected to AGND.

9. A high voltage power supply circuit for an APD detector according to any one of claims 1 to 8, characterized in that: The temperature sensor output conditioning circuit includes a precision operational amplifier, resistors R14, R15, R16, R17, R18, and R19, and capacitors C4, C5, C6, and C7; the first pin and the seventh pin of the precision operational amplifier are electrically connected to the analog input interface of the XADC inside the SoC processor, the second pin and the sixth pin of the precision operational amplifier are electrically connected to the temperature sensor through resistors R15 and R18 respectively, the resistor R14 is connected between the first pin and the second pin of the precision operational amplifier, the resistor R16 is connected between the sixth pin and the seventh pin of the precision operational amplifier, the fourth pin of the precision operational amplifier is connected to -5VA, one end of the capacitors C6 and C7 is connected in parallel to the fourth pin of the precision operational amplifier and the other end is connected to AGND, the eighth pin of the precision operational amplifier is connected to +5VA, one end of the capacitors C4 and C5 is connected in parallel to the eighth pin of the precision operational amplifier and the other end is connected to AGND, and one end of the resistor R19 is connected to the fifth pin of the precision operational amplifier and the other end is connected to AGND.

10. A closed-loop control method for a high-voltage power supply circuit of an APD detector according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: The APD detector high voltage power supply circuit performs a power-on self-test and the SoC processor initializes and configures the initial resistance value R of the digital potentiometer FBL0 , the high voltage output circuit outputs an initial voltage VHV0; Step 2: The SoC processor collects and solves the working environment temperature of the APD detector as room temperature T0. The SoC processor looks up the table to obtain the high voltage value corresponding to the best response at the temperature T0, and calculates the resistance value R that the digital potentiometer should output. FBL1 , so that the high voltage output circuit outputs the target high voltage value VHV1; Step 3: At the same time, the SoC processor collects and calculates the high voltage value VHV2 of the actual high voltage output circuit of the APD detector through the high voltage conditioning circuit. At this time, the corresponding digital potentiometer resistance is R FBL2 ; If VHV2 = VHV1 ± 3V, the high-voltage power supply circuit output is normal; otherwise, the SoC processor needs to continue to configure the digital potentiometer to close the loop and adjust the high-voltage output circuit output until the VHV2 = VHV1 ± 3V condition is met; Step 4: When the operating temperature of the APD quadrant detector changes, for example, when it is stable at T1, if T1 > T0, the high voltage for the optimal responsivity of the APD quadrant detector is VHV3 = VHV1 + (T1 - T0) × δ; if T1 < T0, the high voltage for the optimal responsivity of the APD detector is VHV3 = VHV1 + (T0 - T1) × δ, where δ is the high voltage supply temperature coefficient of the APD detector; then the SoC processor calculates the digital potentiometer resistance value R corresponding to the target high voltage. FBL3 And configure the output; the high voltage output circuit outputs the target high voltage value VHV3; the SoC processor calibrates the target high voltage VHV3 according to Step 3 through the high voltage conditioning circuit.

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