Automatic temperature compensation circuit for APD bias voltage and golf range finder

Abstract

The application provides an APD bias voltage automatic temperature compensation circuit and a golf range finder, wherein a low-voltage power supply is supplied to a conversion unit by an input unit, the conversion unit boosts the voltage and outputs a high voltage required by the APD through an output unit, a temperature detection and signal conditioning unit collects the ambient temperature in real time and completes signal amplification and filtering to obtain a temperature feedback signal, a voltage sampling unit collects a sampling signal by dividing the output high voltage, and a temperature compensation feedback unit superimposes the two types of signals to generate a composite voltage signal which is fed back to the conversion unit, and the conversion unit dynamically adjusts the switch duty cycle according to the composite voltage to adaptively correct the output bias high voltage; the circuit only uses general resistors, capacitors, operational amplifiers and voltage boosting chips, has small size and low cost, solves the defects of high power consumption of the traditional TEC constant temperature and the response lag of the MCU+DAC digital compensation, can stabilize the APD avalanche gain in the whole temperature range, and improves the ranging precision of the golf range finder. The application also protects a laser ranging device carrying the circuit.

Description

Technical Field

[0001] This application relates to the field of photoelectric detection technology, and in particular to an APD bias voltage automatic temperature compensation circuit and a golf rangefinder. Background Technology

[0002] In golf rangefinders, avalanche photodiodes (APDs) are commonly used as the core photodetectors. APDs have advantages such as high sensitivity and fast response speed, but their avalanche gain varies drastically with temperature and bias voltage. The avalanche breakdown voltage of an APD has a positive temperature coefficient, meaning that if the bias voltage remains constant when the ambient temperature changes, its gain will change significantly, leading to a decrease in ranging accuracy or even failure to function.

[0003] In existing technologies, constant temperature control (such as thermoelectric coolers) or digital bias compensation (MCU+DAC solution) are usually used to stabilize APD gain. However, constant temperature control has high power consumption and high cost, which is not conducive to the portability of handheld devices. Digital compensation schemes rely on software algorithms and complex peripheral circuits, and their response speed and reliability are limited in some scenarios. Summary of the Invention

[0004] The technical problem to be solved by this application is that in the prior art, in order to stabilize the APD gain, constant temperature control (such as semiconductor cooling chip) or digital bias compensation (MCU+DAC solution) is usually adopted. However, constant temperature control has high power consumption and high cost, which is not conducive to the portability of handheld devices. Digital compensation scheme relies on software algorithms and complex peripheral circuits, and the response speed and reliability are limited in some scenarios.

[0005] To address the aforementioned issues, this application provides an APD bias voltage automatic temperature compensation circuit and a golf rangefinder.

[0006] In a first aspect, the present invention discloses an APD bias voltage automatic temperature compensation circuit, which includes an input unit, a conversion unit, a temperature detection and signal conditioning unit, a voltage sampling unit, a temperature compensation feedback unit, and an output unit. The input unit is connected to the conversion unit, the conversion unit is connected to the voltage sampling unit and the temperature compensation feedback unit respectively, the temperature compensation feedback unit is connected to the temperature detection and signal conditioning unit, and the output unit is connected to the conversion unit and the voltage sampling unit respectively. The input unit acquires low-voltage input power into the conversion unit, and the output unit outputs a bias high-voltage power supply. The temperature detection and signal conditioning unit senses changes in ambient temperature and generates an initial temperature signal. After amplification and filtering, it outputs a temperature feedback signal. The voltage sampling unit acquires the voltage divider sampling signal of the bias high-voltage power supply. The temperature compensation feedback unit superimposes the temperature feedback signal and the voltage divider sampling signal to output a composite voltage signal. The composite voltage signal is fed back to the conversion unit, and the conversion unit dynamically adjusts the duty cycle of the output signal according to the changes in the composite voltage signal, thereby changing the output bias high-voltage power supply of the output unit.

[0007] Preferably, the conversion unit includes a signal processing subunit and a boost conversion subunit, which are connected together. The signal processing subunit is also connected to the input unit and the output unit.

[0008] Preferably, the boost converter subunit includes a boost DC-DC converter, the fifth terminal of which is connected to the first terminal of the boost DC-DC converter, and the third terminal is connected to the temperature compensation feedback unit and the voltage sampling unit.

[0009] Preferably, the temperature detection and signal conditioning unit includes a temperature detection subunit, a signal conditioning subunit, and a bias voltage divider subunit. The temperature detection subunit is connected to the signal conditioning subunit, and the bias voltage divider subunit is connected to the temperature detection subunit.

[0010] Preferably, the temperature detection subunit includes an NTC thermistor.

[0011] Preferably, the signal conditioning subunit includes an amplifier, the non-inverting input of which is connected to the bias voltage divider subunit and the temperature detection subunit, the inverting input is connected to the output, and the output is connected to the third terminal of the boost DC-DC converter.

[0012] Preferably, the voltage sampling unit includes a first voltage divider resistor and a second voltage divider resistor, with one end of the first voltage divider resistor connected to the second voltage divider resistor and the other end connected to the output unit.

[0013] Preferably, the temperature compensation feedback unit includes a feedback resistor and a gain adjustment resistor. The gain adjustment resistor is connected to the output terminal of the amplifier, and the gain adjustment resistor is connected in series with the feedback resistor.

[0014] Secondly, the present invention discloses a golf rangefinder, which includes the aforementioned APD bias voltage automatic temperature compensation circuit.

[0015] Preferably, it includes an avalanche photodiode, a laser emitting module, an optical receiving module, and a control module; The control module is connected to the avalanche photodiode, the laser emitting module, the optical receiving module, and the APD bias voltage automatic temperature compensation circuit, respectively. The APD bias voltage automatic temperature compensation circuit is connected to the avalanche photodiode. The avalanche photodiode is positioned close to the temperature detection subunit.

[0016] The technical solution provided in this application has the following advantages compared with the prior art: The APD bias voltage automatic temperature compensation circuit and golf rangefinder provided in this application, as mentioned in the APD bias voltage automatic temperature compensation circuit, involve an input unit supplying low-voltage power to a conversion unit. After the conversion unit boosts the voltage, the output unit outputs the high bias voltage required by the APD. A temperature detection and signal conditioning unit collects the ambient temperature in real time and performs signal amplification and filtering to obtain a temperature feedback signal. A voltage sampling unit divides the output high voltage to obtain a sampling signal. A temperature compensation feedback unit hardware superimposes the two types of signals to generate a composite voltage signal and sends it back to the conversion unit. The conversion unit dynamically adjusts the switching duty cycle based on the composite voltage to adaptively correct the output bias high voltage. This scheme adopts a pure analog hardware closed loop. The compensation architecture eliminates the need for an MCU to participate in temperature compensation calculations, thus eliminating software compensation delays. It relies on general-purpose resistors, capacitors, operational amplifiers, and boost chips to build the circuit, eliminating high-cost components such as semiconductor cooling chips, DACs, and high-precision reference sources. The hardware peripheral circuit is simple and the PCB area is small. At the same time, the conversion unit can be controlled by the MCU to cut off the high-voltage output in standby mode, which greatly reduces the static power consumption of the whole machine. It not only solves the defects of high power consumption, high cost, and inconvenience of handheld portability of constant temperature solutions, but also overcomes the shortcomings of slow response, complex circuits, and limited reliability of digital compensation solutions. It can automatically adjust the APD bias voltage in real time according to the temperature, stabilize the APD avalanche gain throughout the process, and improve the stability of photoelectric detection across the entire temperature range.

[0017] The golf rangefinder mentions that it integrates an automatic temperature compensation circuit for the APD bias voltage inside the rangefinder. The compensation circuit outputs a high voltage to directly provide an adaptive bias voltage for the APD inside the device. Relying on the advantages of the compensation circuit, such as no software delay, low cost, low standby power consumption, and miniaturization, the golf rangefinder does not need to be equipped with a cooling module and DAC digital compensation peripherals. The overall hardware size and material cost are reduced, and the battery life is significantly improved. In outdoor golf measurement scenarios such as high and low temperatures and sudden temperature changes, it can stabilize the APD avalanche gain in real time, suppress the ranging error caused by temperature drift, and improve the ranging range and measurement accuracy. At the same time, it simplifies the overall hardware design and production calibration process, and improves the mass production reliability and outdoor adaptability of the device. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A block diagram of an APD bias voltage automatic temperature compensation circuit provided in this application; Figure 2 A circuit diagram of an APD bias voltage automatic temperature compensation circuit provided in this application; Figure 3 A circuit diagram of the conversion unit of an APD bias voltage automatic temperature compensation circuit provided in this application; Figure 4 A circuit diagram of a temperature detection and signal conditioning unit for an APD bias voltage automatic temperature compensation circuit provided in this application; Figure 5 A structural block diagram of a golf rangefinder provided in this application.

[0021] Explanation of reference numerals in the attached figures: 100. Golf rangefinder; 1. Automatic temperature compensation circuit for APD bias voltage; 11. Input unit; 12. Conversion Unit; 121. Signal Processing Subunit; 122. Boost Conversion Subunit; 13. Temperature detection and signal conditioning unit; 131. Temperature detection subunit; 132. Signal conditioning subunit; 133. Bias voltage divider subunit; 14. Voltage sampling unit; 15. Temperature compensation feedback unit; 16. Output unit; 2. Avalanche photodiode; 3. Laser emitting module; 4. Optical receiving module; 5. Control module. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] Firstly, see Figures 1-4 This invention discloses an APD bias voltage automatic temperature compensation circuit 1, which includes an input unit 11, a conversion unit 12, a temperature detection and signal conditioning unit 13, a voltage sampling unit 14, a temperature compensation feedback unit 15, and an output unit 16. The input unit 11 is connected to the conversion unit 12, the conversion unit 12 is connected to the voltage sampling unit 14 and the temperature compensation feedback unit 15, the temperature compensation feedback unit 15 is connected to the temperature detection and signal conditioning unit 13, and the output unit 16 is connected to the conversion unit 12 and the voltage sampling unit 14.

[0024] Input unit 11 acquires low-voltage input power into conversion unit 12, output unit 16 outputs bias high-voltage power, temperature detection and signal conditioning unit 13 senses changes in ambient temperature to generate an initial temperature signal, amplifies and filters it, and outputs a temperature feedback signal, voltage sampling unit 14 acquires the voltage divider sampling signal of the bias high-voltage power supply, temperature compensation feedback unit 15 superimposes the temperature feedback signal and the voltage divider sampling signal to output a composite voltage signal, the composite voltage signal is fed back to conversion unit 12, conversion unit 12 dynamically adjusts the duty cycle of the output signal of conversion unit 12 according to the change of composite voltage signal, and changes the output bias high-voltage power supply output by output unit 16.

[0025] Specifically, the input unit 11 supplies low-voltage power to the conversion unit 12. After the conversion unit 12 boosts the voltage, the output unit 16 outputs the high bias voltage required by the APD. The temperature detection and signal conditioning unit 13 collects the ambient temperature in real time and performs signal amplification and filtering to obtain a temperature feedback signal. The voltage sampling unit 14 divides the output high voltage to obtain a sampling signal. The temperature compensation feedback unit 15 hardware superimposes the two types of signals to generate a composite voltage signal and sends it back to the conversion unit 12. The conversion unit 12 dynamically adjusts the switching duty cycle according to the composite voltage to adaptively correct the output bias high voltage. This scheme adopts a pure analog hardware closed-loop compensation architecture, which does not require the MCU to participate in temperature control. The compensation operation eliminates software compensation delay. It relies on general-purpose resistors, capacitors, operational amplifiers, and boost chips to build the circuit, eliminating the need for high-cost components such as semiconductor cooling chips, DACs, and high-precision reference sources. The hardware peripheral circuit is simple and the PCB area is small. At the same time, the conversion unit 12 can be controlled by the MCU to cut off the high voltage output in standby mode, which greatly reduces the static power consumption of the whole machine. It not only solves the defects of high power consumption, high cost, and inconvenience of handheld portability of constant temperature solution, but also overcomes the shortcomings of slow response, complex circuit, and limited reliability of digital compensation solution. It can automatically adjust the APD bias voltage in real time according to the temperature, stabilize the APD avalanche gain throughout the process, and improve the stability of photoelectric detection in the whole temperature range.

[0026] Input unit 11 receives the low-voltage power supply signal LRF_4V0, providing low-voltage power to conversion unit 12. Input unit 11 consists only of input terminals and decoupling capacitor C24. The input terminals are connected to the low-voltage power supply signal LRF_4V0, and one end of decoupling capacitor C24 is connected to LRF_4V0, while the other end is grounded (GND). The overall output is connected to conversion unit 12. Decoupling capacitor C24 is used to filter out high-frequency ripple interference in the low-voltage power supply, ensuring that the low-voltage power supply input to conversion unit 12 is pure and stable. The core function of input unit 11 is to continuously provide clean basic low-voltage power to conversion unit 12. Output unit 16 outputs the bias high-voltage power supply APD_BV of APD, used to trigger the avalanche multiplication effect and achieve high-gain photoelectric conversion.

[0027] The conversion unit 12 includes a signal processing subunit 121 and a boost conversion subunit 122, which are connected. The signal processing subunit 121 is also connected to the input unit 11 and the output unit 16. Specifically, the conversion unit 12 is divided into a signal processing subunit 121 and a boost conversion subunit 122, which are interconnected. The signal processing subunit 121 is also connected to the input unit 11 and the output unit 16. The boost conversion subunit 122 includes an energy storage inductor L6, a rectifier diode D5, a built-in power switch Q2, a first filter capacitor C25, and an isolation resistor R52. Its core function is to perform power boost conversion from the low voltage LRF_4V0 to the high voltage APD_BV by relying on the inductor for energy storage and the diode for unidirectional rectification, providing an adjustable avalanche bias high voltage for the output unit 16. The signal processing subunit 121 is based on a boost DC-DC chip U11 and is equipped with an enable current limiting resistor R54. On one hand, it is connected to the VIN pin. The input unit receives LRF_4V0 low-voltage power supply, and receives external signals, namely the MCU_EN level signal of the control module, through the EN pin to realize the on / off control of the boost circuit. On the other hand, the composite voltage signal superimposed by the voltage sampling unit 14 and the temperature compensation feedback unit 15 is received synchronously through the FB pin. The internal logic adjusts the duty cycle of the switching transistor Q2 in the boost converter subunit 122 in real time according to the composite voltage, thereby dynamically adjusting the boost output amplitude. At the same time, the chip's SW pin is interconnected with the power device of the boost converter subunit 122 to complete the interaction between the control signal and the power circuit. Finally, it realizes the adaptive adjustment of the APD bias high voltage based on temperature and high voltage sampling feedback, and supports the standby power-off to reduce the overall power consumption.

[0028] The boost converter subunit 122 includes a boost DC-DC converter U11. The fifth and first terminals of the boost DC-DC converter are connected to the signal processing subunit 121, and the third terminal is connected to the temperature compensation feedback unit 15 and the voltage sampling unit 14. Specifically, the core device of the boost converter subunit 122 is the boost DC-DC converter U11. The first terminal VIN and the fifth terminal EN of U11 are both connected to the signal processing subunit 121. The signal processing subunit 121 supplies the LRF_4V0 low-voltage power supply output from the input unit 11 to the VIN terminal, and simultaneously receives the MCU_EN enable control level via the fifth terminal EN, thereby realizing the start and stop control of the boost circuit. The third terminal FB of U11 serves as a feedback aggregation pin, and is electrically connected to the temperature compensation feedback unit 15 and the voltage sampling unit 14, enabling it to synchronously receive the high-voltage divider sampling signal output from the voltage sampling unit 14 and the temperature feedback output from the temperature compensation feedback unit 15. The two signals are superimposed at the FB pin to form a composite feedback voltage, which is then fed into U11. The internal circuit of U11 dynamically adjusts the duty cycle of the internal power switch based on the amplitude of the composite voltage at the FB pin. This, along with the energy storage inductor L6, rectifier diode D5, first filter capacitor C25, and isolation resistor R52 of the sub-unit, completes the low-voltage boost power conversion. Finally, the output unit 16 is given an adaptively adjustable APD_BV avalanche bias high voltage via R52. L6 is used for energy storage to achieve boost energy conversion, D5 provides unidirectional isolation to prevent energy backflow, the first filter capacitor C25 stabilizes the boost intermediate node voltage, and R52 buffers high voltage spikes and protects the subsequent circuitry.

[0029] The temperature detection and signal conditioning unit 13 includes a temperature detection subunit 131, a signal conditioning subunit 132, and a bias voltage divider subunit 133. The temperature detection subunit 131 is connected to the signal conditioning subunit 132, and the bias voltage divider subunit 133 is connected to the temperature detection subunit 131.

[0030] Specifically, the bias voltage divider subunit 133 is connected to the temperature detection subunit 131, and the temperature detection subunit 131 is then connected to the signal conditioning subunit 132. The bias voltage divider subunit 133 is used to provide a stable reference voltage divider power supply, and works with the temperature detection subunit 131 to convert the ambient temperature change into a recognizable raw analog temperature signal. The temperature detection subunit 131 is responsible for sensing the ambient temperature around the device in real time and outputting an initial electrical signal that changes with the temperature. The signal conditioning subunit 132 receives the raw temperature signal from the temperature detection subunit 131, and simultaneously performs amplification, noise reduction and filtering on the signal to output a standardized, stable and interference-free temperature feedback signal, which is supplied to the back-end temperature compensation feedback unit 15 for feedback superposition and adjustment.

[0031] The temperature detection subunit 131 includes an NTC thermistor, which is used to sense the ambient temperature and convert it into an electrical signal.

[0032] The signal conditioning subunit 132 includes an amplifier U16. The non-inverting input of the amplifier is connected to the bias voltage divider subunit 133 and the temperature detection subunit 131, respectively. The inverting input is connected to the output, and the output is connected to the third terminal of the boost DC-DC converter.

[0033] Specifically, the core device of the signal conditioning subunit 132 is amplifier U16. The non-inverting input of U16 is electrically connected to both the bias voltage divider subunit 133 and the temperature detection subunit 131 to receive the original temperature voltage signal generated by both subunits and that varies with temperature. The inverting input and output of U16 are interconnected to form a closed-loop amplification topology, which realizes proportional amplification of the original temperature signal. The output of amplifier U16 is connected to the third terminal FB of a boost DC-DC converter, which can send the amplified and smoothed stable temperature feedback signal to the feedback aggregation node. Amplifier U16 is responsible for amplifying the weak temperature sampling signal, improving the temperature signal regulation capability, and adapting to the feedback control requirements of the boost circuit. At the same time, the signal amplification gain can be flexibly set through the closed-loop structure of the inverting input and the output, ensuring that the temperature compensation adjustment slope matches the temperature characteristics of the APD device.

[0034] The voltage sampling unit 14 includes a first voltage divider resistor R50, a second voltage divider resistor R51, a second filter capacitor C26, and a third filter capacitor C31. One end of the first voltage divider resistor R50 is connected to the second voltage divider resistor R51, and the other end is connected to the output unit 16.

[0035] Specifically, one end of the first voltage divider resistor R50 is connected to the output unit 16 to obtain the APD_BV bias high voltage, and the other end is connected to the second voltage divider resistor R51. The other end of the second voltage divider resistor R51 is grounded. The two are connected in series to form a voltage divider branch and are connected to the third terminal FB of the boost DC-DC converter at the connection point of the two resistors. The second filter capacitor C26 and the third filter capacitor C31 are connected in parallel between the APD_BV high voltage node of the output unit 16 and ground. R50 and R51 work together to perform resistive voltage division on the hundred-volt bias high voltage, generating a sampling current of the corresponding output voltage magnitude and sending it to the FB feedback node to provide high voltage reference feedback for the boost circuit. The second filter capacitor C26 and the third filter capacitor C31 filter the APD_BV high voltage output to filter out the high frequency noise brought by the boost switch, prevent the boost conversion loop from oscillating, and ensure that the sampling signal is stable and reliable.

[0036] The temperature compensation feedback unit 15 includes a feedback resistor R57 and a gain adjustment resistor R56. The gain adjustment resistor is connected to the output terminal of the amplifier and is connected in series with the feedback resistor.

[0037] Specifically, one end of the gain adjustment resistor R56 is grounded, and the other end is connected to the inverting input terminal of amplifier U16. The feedback resistor R57 is connected in series between the output terminal and the inverting input terminal of amplifier U16. At the same time, the end of the feedback resistor R57 away from the op-amp is electrically connected to the third terminal FB of the boost DC-DC converter. The gain adjustment resistor and the feedback resistor R57 together form a non-inverting amplification gain circuit, which together determine the amplification factor of the temperature signal. This is used to adjust the adjustment slope of the temperature compensation to adapt to the temperature characteristics of different APDs. The feedback resistor R57 also serves as a signal isolation and current transmission device, converting the temperature feedback voltage output by the amplifier into a compensation current and sending it to the FB node. This current is superimposed with the sampling current of the voltage sampling unit 14 to form a composite feedback signal, thereby realizing the dynamic adjustment of the APD bias high voltage by temperature.

[0038] When the ambient temperature rises, the resistance of the NTC thermistor decreases, causing a change in the voltage at the non-inverting input of amplifier U16. Amplifier U16 amplifies this change, increasing the output control voltage and forcing the SW pin of boost DC-DC converter U11 to output a higher duty cycle. This increases the reverse bias voltage of the APD, compensating for the increased avalanche voltage demand of the APD due to temperature rise. Conversely, when the temperature decreases, the resistance of the NTC thermistor increases, the output of amplifier U16 decreases, and boost DC-DC converter U11 reduces the bias voltage to maintain a constant APD gain.

[0039] Secondly, see Figure 5 This invention discloses a golf rangefinder, which includes the aforementioned APD bias voltage automatic temperature compensation circuit 1. Specifically, the APD bias voltage automatic temperature compensation circuit 1 is integrated inside the golf rangefinder. The compensation circuit outputs a high voltage to directly provide an adaptive bias voltage to the APD inside the device. Relying on the advantages of the compensation circuit—no software delay, low cost, low standby power consumption, and miniaturization—this golf rangefinder does not require a cooling module or DAC digital compensation peripheral. The overall hardware size and material cost are reduced, and the battery life is significantly improved. In outdoor golf measurement scenarios such as high and low temperatures and sudden temperature changes, it can stabilize the APD avalanche gain in real time, suppress the ranging error caused by temperature drift, and improve the ranging range and measurement accuracy. At the same time, it simplifies the overall hardware design and production calibration process, improving the mass production reliability and outdoor adaptability of the device.

[0040] The golf rangefinder includes an avalanche photodiode 2, a laser emitting module 3, an optical receiving module 4, and a control module 5. The control module 5 is connected to the avalanche photodiode 2 (APD), the laser emitting module 3, the optical receiving module 4, and the APD bias voltage automatic temperature compensation circuit 1. The APD bias voltage automatic temperature compensation circuit 1 is connected to the avalanche photodiode 2, and the avalanche photodiode 2 is positioned close to the temperature detection subunit 131.

[0041] Specifically, in the golf rangefinder, the control module 5 is electrically connected to the avalanche photodiode 2, the laser emitting module 3, the optical receiving module 4, and the APD bias voltage automatic temperature compensation circuit 1. The output of the APD bias voltage automatic temperature compensation circuit 1 is connected to the avalanche photodiode 2. The avalanche photodiode 2 is arranged close to the temperature detection subunit 131. The laser emitting module 3 is used to emit the ranging laser beam, and the optical receiving module 4 is used to collect the reflected light from the ranging laser beam and conduct it to the avalanche photodiode 2. The avalanche photodiode 2 completes the high-gain photoelectric signal conversion with the help of the adjustable bias high voltage provided by the compensation circuit. The control module 5 coordinates the signal transmission and reception of the whole machine, the ranging calculation and the start and stop control of the compensation circuit. The temperature detection subunit 131 collects the temperature around the avalanche photodiode 2 at close range to ensure the compensation accuracy.

[0042] When the golf rangefinder is running, the control module 5 drives the laser emitting module 3 to emit a ranging laser. After the laser is reflected by the target, it is focused by the optical receiving module 4 onto the avalanche photodiode 2. The temperature detection subunit 131 collects the operating temperature of the avalanche photodiode 2 in real time and converts it into a temperature signal, which is sent to the APD bias voltage automatic temperature compensation circuit 1. The compensation circuit superimposes the temperature feedback signal and the high voltage sampling signal to generate a composite feedback signal, and dynamically and adaptively adjusts the bias high voltage supplied to the avalanche photodiode 2 to offset the gain drift caused by temperature. The avalanche photodiode 2 converts the light signal into an electrical pulse and sends it back to the control module 5 to complete the distance calculation, realizing stable and high-precision ranging across the entire temperature range.

[0043] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0044] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0049] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Since these modifications and variations fall within the scope of the claims and their equivalents, this invention also intends to include these modifications and variations.

[0050] The above description describes specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An APD bias voltage automatic temperature compensation circuit, characterized in that, It includes an input unit, a conversion unit, a temperature detection and signal conditioning unit, a voltage sampling unit, a temperature compensation feedback unit, and an output unit. The input unit is connected to the conversion unit, the conversion unit is connected to the voltage sampling unit and the temperature compensation feedback unit respectively, the temperature compensation feedback unit is connected to the temperature detection and signal conditioning unit, and the output unit is connected to the conversion unit and the voltage sampling unit respectively. The input unit acquires low-voltage input power into the conversion unit, the output unit outputs bias high-voltage power, the temperature detection and signal conditioning unit senses changes in ambient temperature to generate an initial temperature signal, and after amplification and filtering, outputs a temperature feedback signal, the voltage sampling unit acquires the voltage divider sampling signal of the bias high-voltage power supply, the temperature compensation feedback unit superimposes the temperature feedback signal and the voltage divider sampling signal to output a composite voltage signal, the composite voltage signal is fed back to the conversion unit, and the conversion unit dynamically adjusts the duty cycle of the output signal of the conversion unit according to the changes in the composite voltage signal, thereby changing the output bias high-voltage power supply of the output unit; The conversion unit includes a signal processing subunit and a boost conversion subunit, which are connected together. The signal processing subunit is also connected to the input unit and the output unit. The boost converter subunit includes a boost DC-DC converter. The fifth terminal and the first terminal of the boost DC-DC converter are connected to the signal processing subunit, and the third terminal is connected to the temperature compensation feedback unit and the voltage sampling unit.

2. The circuit according to claim 1, characterized in that, The input unit receives a low-voltage power signal to provide low-voltage power to the conversion unit. It only includes an input terminal and a decoupling capacitor. The input terminal is connected to the low-voltage power supply, and one end of the decoupling capacitor is connected to the input terminal and the other end is grounded. Decoupling capacitors are used to filter out high-frequency ripple interference in low-voltage power supplies.

3. The circuit according to claim 1, characterized in that, The signal processing subunit acquires low-voltage power supply signals through the input unit to achieve low-voltage power supply and controls the on / off state of the boost circuit by receiving external level signals. On the other hand, it synchronously receives the composite voltage signal superimposed by the voltage sampling unit and the temperature compensation feedback unit. The internal logic adjusts the duty cycle of switch Q2 in the boost converter subunit in real time according to the composite voltage to dynamically adjust the boost output amplitude.

4. The circuit according to claim 1, characterized in that, The temperature detection and signal conditioning unit includes a temperature detection subunit, a signal conditioning subunit, and a bias voltage divider subunit. The temperature detection subunit is connected to the signal conditioning subunit, and the bias voltage divider subunit is connected to the temperature detection subunit.

5. The circuit according to claim 1, characterized in that, The temperature detection subunit includes an NTC thermistor, which is used to sense the ambient temperature and convert it into an electrical signal.

6. The circuit according to claim 1, characterized in that, The signal conditioning subunit includes an amplifier. The non-inverting input of the amplifier is connected to the bias voltage divider subunit and the temperature detection subunit, respectively. The inverting input is connected to the output, and the output is connected to the third terminal of the boost DC-DC converter.

7. The circuit according to claim 1, characterized in that, The voltage sampling unit includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is connected to the second voltage divider resistor, and the other end is connected to the output unit.

8. The circuit according to claim 1, characterized in that, The temperature compensation feedback unit includes a feedback resistor and a gain adjustment resistor. The gain adjustment resistor is connected to the output terminal of the amplifier, and the gain adjustment resistor is connected in series with the feedback resistor.

9. A golf rangefinder, characterized in that, Includes the APD bias voltage automatic temperature compensation circuit as described in any one of claims 1-8.

10. The golf rangefinder according to claim 9, characterized in that, Includes avalanche photodiodes, laser emitting modules, optical receiving modules, and control modules; The control module is connected to the avalanche photodiode, the laser emitting module, the optical receiving module, and the APD bias voltage automatic temperature compensation circuit, respectively. The APD bias voltage automatic temperature compensation circuit is connected to the avalanche photodiode. The avalanche photodiode is positioned close to the temperature detection subunit.

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