APD package and temperature control method thereof

Abstract

The invention relates to an APD package and a temperature control method thereof, the APD package comprises a first thermistor, a second thermistor, a temperature difference calculation module and a TEC adjusting module, the first thermistor is placed on a refrigeration surface of the TEC adjusting module adjacent to an APD chip; the second thermistor is arranged beside the TEC adjusting module and is used for collecting the environment temperature; and the temperature difference calculation module is used for receiving the temperature collected by the first thermistor and the second thermistor and calculating a corresponding temperature difference. The invention provides an APD package and a temperature control method thereof, which can detect the temperature of an APD chip through a first thermistor, detect the ambient temperature through a second thermistor, and adjust the output of a TEC adjusting module according to the temperature difference between the temperatures detected by the first thermistor and the second thermistor, so that the APD package is more stable and reliable. Therefore, the control of the APD packaging working temperature is realized, and the overall stable working effect is further ensured.

Description

Technical Field

[0001] This application relates to the field of chip packaging technology, and in particular to an APD package and its temperature control method. Background Technology

[0002] An APD chip, or avalanche photodiode chip, is a high-performance semiconductor photodetector with an internal gain mechanism. The operating principle of an APD chip makes its performance extremely sensitive to temperature. Temperature changes affect key parameters such as the APD's multiplication efficiency, gain, dark current, and noise, thus causing its current response to change with temperature. In many applications, such as lidar and optical communication, precise measurement of optical signal parameters is required. Only by controlling the temperature and ensuring the APD chip operates within a stable temperature environment can accurate detection of optical signals be achieved.

[0003] In existing technologies, APD packaging generally adopts a single feedback mode, that is, a thermistor is packaged in the product that needs temperature control, and the internal temperature of the product is fed back in real time through the thermistor.

[0004] APD chips are temperature-sensitive devices, and their breakdown voltage varies with temperature. When calibrating product performance, calibration is typically performed at a fixed product temperature under different ambient temperatures. Temperature changes cause variations in the APD chip's gain. If a constant gain needs to be maintained, the APD chip's operating voltage must be adjusted at different temperatures, resulting in high complexity in the overall system's control circuitry and algorithms. Summary of the Invention

[0005] This application provides an APD package and its temperature control method, aiming to solve the problem that the gain of the APD package is easily affected by temperature changes, and therefore requires complex circuitry to adjust the operating voltage of the APD chip at different temperatures to reduce the impact of temperature.

[0006] In a first aspect, embodiments of this application provide an APD package, including: a first thermistor, a second thermistor, a temperature difference calculation module, and a TEC adjustment module, wherein: The first thermistor is placed on the cooling surface of the TEC regulation module adjacent to the APD chip; The second thermistor is located next to the TEC regulation module and is used to collect ambient temperature. The temperature difference calculation module is used to receive the temperatures collected by the first thermistor and the second thermistor, and calculate the corresponding temperature difference. The TEC regulating module has an APD chip installed on it. The TEC regulating module outputs regulating power based on the temperature difference calculation.

[0007] Furthermore, both the first and second thermistors are NTC thermistors.

[0008] Furthermore, it also includes a closed-loop feedback control module, which compares the product temperature with the target temperature and corrects the regulation power of the TEC regulation module.

[0009] Furthermore, it also includes a substrate and a packaging layer. The TEC adjustment module is disposed on the substrate, the APD chip is disposed on the TEC adjustment module, and the first thermistor is disposed on the TEC adjustment module and disposed next to the APD chip.

[0010] Secondly, embodiments of this application provide an APD package temperature control method, based on the APD package as described above, including the following steps: Two sets of thermistors are configured in the APD package, and the two sets of thermistors are defined as the first thermistor and the second thermistor, respectively. The first thermistor is placed inside the APD package and adjacent to the APD chip to detect the temperature of the APD chip. The second thermistor is placed inside the APD package and used to detect the ambient temperature outside the APD chip; The temperature information collected by the first thermistor and the second thermistor is output and fed back. The temperature difference is calculated based on the output feedback from the first and second thermistors, and then the temperature is adjusted by the TEC adjustment module based on the temperature difference calculation result.

[0011] Furthermore, the first thermistor and the second thermistor adopt a synchronous sampling mechanism to obtain the product temperature and ambient temperature respectively through corresponding sampling circuits.

[0012] Furthermore, the conversion formula between the temperature information and resistance value of the first thermistor and the second thermistor is as follows:

[0013] Where T is the current temperature of the first thermistor or the second thermistor; T0 is the reference temperature of the first or second thermistor; B is the material constant of the first or second thermistor; R is the resistance value of the first or second thermistor at the current temperature; R0 is the resistance value of the first or second thermistor at temperature T0.

[0014] This application provides an APD packaging and its temperature control method, which enables simultaneous detection of the APD chip temperature using a first thermistor and the ambient temperature using a second thermistor. The output of the TEC regulation module is adjusted based on the temperature difference detected by the first and second thermistors, thereby controlling the operating temperature of the APD chip and ensuring overall operational stability. The solution provided in this application significantly improves the operational stability of APD devices under different ambient temperatures and is suitable for high-precision optoelectronic systems such as LiDAR and optical communication. Attached Figure Description The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0015] To more clearly illustrate the technical solutions in the embodiments of this application 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.

[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 An equivalent circuit diagram of an APD package is provided for an embodiment of this application.

[0018] Figure 2 This is a schematic diagram of an APD package provided in an embodiment of this application.

[0019] Figure 3 A bar chart comparing temperature control errors under different ambient temperatures.

[0020] Explanation of reference numerals in the attached figures: 1. APD chip; 2. TEC regulation module; T1, first thermistor; T2, second thermistor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. 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.

[0022] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0023] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0024] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0025] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0026] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0027] To address the problem that the gain of existing APD chips is easily affected by temperature changes, thus requiring complex circuits to adjust the operating voltage of the APD chip at different temperatures to reduce the impact of temperature, this application provides an APD package and its temperature control method. This method enables simultaneous detection of the APD chip temperature using a first thermistor and the ambient temperature using a second thermistor. The output of the TEC regulation module is adjusted based on the temperature difference detected by the first and second thermistors, thereby controlling the operating temperature of the APD chip and ensuring overall stable operation.

[0028] Please see Figure 1 , Figure 2 In a first aspect, embodiments of this application provide an APD package, including: a first thermistor T1, a second thermistor T2, a temperature difference calculation module, and a TEC adjustment module 2, wherein: The first thermistor T1 is placed on the cooling surface of the TEC regulation module 2 adjacent to the APD chip 1; The second thermistor T2 is located next to the TEC regulation module 2 and is used to collect the ambient temperature. The temperature difference calculation module is used to receive the temperatures collected by the first thermistor T1 and the second thermistor T2, and calculate the corresponding temperature difference. The TEC regulating module 2 has an APD chip 1 mounted on it. The TEC regulating module 2 outputs regulating power based on the temperature difference calculation results. During operation, the temperature inside the APD package is detected by a first thermistor T1. Under different temperature conditions, the resistance value of the first thermistor T1 changes, thus determining the corresponding temperature value inside the APD package. Simultaneously, the ambient temperature outside the APD chip 1 is detected by a second thermistor T2. Under different temperature conditions, the resistance value of the second thermistor T2 changes, thus determining the ambient temperature outside the APD chip 1. By analyzing the detected temperature values ​​of the first thermistor T1 and the second thermistor T2, and calculating the corresponding temperature difference, the adjustment power of the TEC adjustment module 2 is adjusted based on the temperature difference. When the TEC adjustment module 2 is activated, because the cold end of the TEC adjustment module 2 absorbs heat and the hot end releases heat, a cooling effect is achieved, lowering the temperature of the APD chip 1 and reducing the heat generated during the operation of the APD chip 1. This ensures that the APD chip 1 can accurately detect and measure optical signals under a stable temperature environment.

[0029] The solution provided in this application can significantly improve the working stability of APD devices under different ambient temperatures, and is suitable for high-precision optoelectronic systems such as lidar and optical communication.

[0030] In some optional embodiments, the first thermistor T1 and the second thermistor T2 are both NTC thermistors. An NTC thermistor is a semiconductor ceramic element whose resistance decreases exponentially with increasing temperature, capable of detecting minute temperature differences at the 0.001°C level, making it suitable for temperature detection requirements under precise temperature control conditions. Furthermore, NTC thermistors have a small overall size; therefore, placing the first thermistor T1 and the second thermistor T2 inside the APD package avoids excessive space occupation within the APD package, ensuring that the overall size of the APD package remains unaffected.

[0031] In some optional embodiments, a closed-loop feedback control module is also included to compare the product temperature with the target temperature and correct the regulation power of the TEC regulation module 2. The system continuously compares the product temperature with the target temperature, and when the temperature exceeds the set target temperature threshold, a new round of regulation is triggered, thereby ultimately achieving a temperature control accuracy of ±0.05℃, meeting the stringent requirements of APD devices for environmental temperature stability.

[0032] In some optional embodiments, a substrate and a packaging layer are also included. The TEC regulation module 2 is disposed on the substrate, the APD chip 1 is disposed on the TEC regulation module 2, and the first thermistor T1 is disposed on the TEC regulation module 2 and next to the APD chip 1. By disposing the entire structure on the TEC regulation module 2 on the substrate, the overall space occupied is effectively reduced. Simultaneously, by placing the second thermistor T2 next to the TEC regulation module 2, interference from the cooling effect of the TEC regulation module 2 on the environmental detection of the second thermistor T2 is avoided.

[0033] Secondly, embodiments of this application provide an APD package temperature control method, based on the APD package as described above, including the following steps: Two sets of thermistors are configured in the APD package, and the two sets of thermistors are defined as the first thermistor T1 and the second thermistor T2 respectively. The first thermistor T1 is placed inside the APD package and adjacent to the APD chip 1 to detect the temperature of the APD chip 1. The second thermistor T2 is placed inside the APD package and is used to detect the ambient temperature outside the APD chip 1. The temperature information collected by the first thermistor T1 and the second thermistor T2 is output and fed back. The temperature difference is calculated based on the output feedback from the first thermistor T1 and the second thermistor T2, and then the temperature is adjusted by the TEC adjustment module 2 based on the temperature difference calculation result.

[0034] During operation, the temperature of the APD chip 1 is detected by a first thermistor T1. The resistance value of the first thermistor T1 changes under different temperature conditions, thus determining the corresponding temperature value of the APD chip 1. Simultaneously, the ambient temperature outside the APD chip 1 is detected by a second thermistor T2. The resistance value of the second thermistor T2 changes under different temperature conditions, thus determining the ambient temperature outside the APD chip 1. By analyzing the detected temperature values ​​of the first thermistor T1 and the second thermistor T2, the corresponding temperature difference is calculated, and the adjustment power of the TEC adjustment module 2 is adjusted based on this temperature difference. When the TEC adjustment module 2 is activated, because the cold end of the TEC adjustment module 2 absorbs heat and the hot end releases heat, a cooling effect is achieved, lowering the temperature of the APD chip 1 and reducing the heat generated during the operation of the APD chip 1. This ensures that the APD chip 1 can accurately detect and measure optical signals under a stable temperature environment.

[0035] In some optional embodiments, the first thermistor T1 and the second thermistor T2 employ a synchronous sampling mechanism, acquiring the product temperature and ambient temperature respectively through corresponding sampling circuits. In some embodiments, the sampling interval is set to 200ms to ensure the consistency of temperature difference calculation time.

[0036] In some optional embodiments, the NTC-based B-parameter model converts the acquired resistance values ​​into absolute temperature. The conversion formula between the temperature information and resistance values ​​of the first thermistor T1 and the second thermistor T2 is as follows:

[0037] Where T is the current temperature of the first thermistor T1 or the second thermistor T2; T0 is the reference temperature of either the first thermistor T1 or the second thermistor T2; B is the material constant of the first thermistor T1 or the second thermistor T2; R is the resistance value of the first thermistor T1 or the second thermistor T2 at the current temperature; R0 is the resistance value of the first thermistor T1 or the second thermistor T2 at temperature T0.

[0038] This system employs a dual-NTC temperature sensing architecture to achieve precise temperature control of the APD device. The core hardware layout includes: a product-side NTC sensor tightly fitted to the APD housing surface, with thermal grease ensuring a thermal resistance of less than 0.5℃ / W, for real-time acquisition of the device junction temperature; and an environmental-side NTC installed at the module housing ventilation holes to avoid interference from local heat sources, used for monitoring the external ambient temperature. Both NTC signals undergo noise suppression via an RC low-pass filter circuit, with a cutoff frequency of approximately 15.9Hz, effectively filtering out high-frequency interference before being connected to the MCU's 12-bit ADC interface, achieving a sampling accuracy of ±0.1℃.

[0039] The temperature of APD chip 1 is detected by a first thermistor T1. The resistance value of the first thermistor T1 changes under different temperature conditions, thus determining the corresponding temperature value of APD chip 1. Simultaneously, the ambient temperature outside APD chip 1 is detected by a second thermistor T2. The resistance value of the second thermistor T2 changes under different temperature conditions, thus determining the ambient temperature outside APD chip 1. By analyzing the detected temperature values ​​of the first thermistor T1 and the second thermistor T2, the corresponding temperature difference is calculated, and the adjustment power of the TEC adjustment module 2 is adjusted based on this temperature difference. When the TEC adjustment module 2 is activated, because the cold end of the TEC adjustment module 2 absorbs heat and the hot end releases heat, a cooling effect is achieved, lowering the temperature of APD chip 1 and reducing the heat generated during the operation of APD chip 1. This ensures that APD chip 1 can accurately detect and measure optical signals under a stable temperature environment. Through the modular design and refined algorithm described above, the system can stabilize the operating temperature of the APD chip 1 within the set value of ±0.3℃, and maintain good photodetection performance in ambient temperatures ranging from -40℃ to 60℃.

[0040] System Testing and Result Analysis Please see Figure 3 To verify the performance of the APD temperature control system with dual NTC temperature detection, this chapter adopts a logical framework of "test plan - data presentation - results discussion" to comprehensively evaluate the temperature control accuracy of the system under different ambient temperatures.

[0041] Test plan design The experimental platform was set up as follows: The APD module was placed in a programmable high and low temperature chamber to simulate a wide temperature environment from -40℃ to 85℃. Dual NTC sensors were connected to the STM32H743 microcontroller development board via I2C bus to collect module temperature data in real time. The host computer communicated with the development board via USB serial port, recording the deviation between the target temperature and the actual temperature of the temperature control system at a sampling rate of 1Hz. The experiment lasted for 30 minutes at each temperature point to ensure data reliability.

[0042] Experimental data presentation The system temperature control error test results under different ambient temperatures are shown in Table 1. The data shows that the system maintains high control accuracy across the entire temperature range. The error is smallest in the normal temperature range (25℃), while the error is slightly larger in the low temperature range (-40℃) but still within an acceptable range.

[0043] Table 1 System temperature control error test results

[0044] Further analysis shows that the minimum error at 25℃ (±0.02℃) is due to the stability of the NTC's B-value in the room temperature range and the high-precision sampling of the STM32H743's built-in 24-bit ADC. The error at high temperature (85℃) (±0.04℃) is related to the decreased heat conduction efficiency of the heat sink, which can be further improved by optimizing the copper area in the PCB layout. For the error at low temperature, it is recommended to use a segmented B-value calibration algorithm, introducing third-order fitting compensation in the -40℃ to 0℃ range, which theoretically can control the error within ±0.03℃.

[0045] Overall test results show that the dual-NTC temperature control system fully meets the stringent temperature stability requirements of APD devices, providing a reliable temperature control solution for high-precision optoelectronic systems such as laser ranging and optical communication.

[0046] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0047] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of each unit is merely a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0048] The steps in the methods of this application embodiment can be adjusted, merged, or deleted according to actual needs. The units in the apparatus of this application embodiment can be merged, divided, or deleted according to actual needs. Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0049] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a terminal, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0050] 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.

[0051] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Since these modifications and variations fall within the scope of the claims and their equivalents, this application also intends to include these modifications and variations.

[0052] The above description is merely a specific embodiment of this application, but the scope of protection of this application 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 this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An APD package, characterized in that, include: The system comprises a first thermistor, a second thermistor, a temperature difference calculation module, and a TEC adjustment module, wherein: The first thermistor is placed on the cooling surface of the TEC regulation module adjacent to the APD chip; The second thermistor is located next to the TEC regulation module and is used to collect ambient temperature. The temperature difference calculation module is used to receive the temperatures collected by the first thermistor and the second thermistor, and calculate the corresponding temperature difference. The TEC regulating module has an APD chip installed on it. The TEC regulating module outputs regulating power based on the temperature difference calculation.

2. The APD package according to claim 1, characterized in that, The first thermistor and the second thermistor are both NTC thermistors.

3. The APD package according to claim 1, characterized in that, It also includes a closed-loop feedback control module, which compares the product temperature with the target temperature and corrects the regulation power of the TEC regulation module.

4. The APD package according to claim 1, characterized in that, It also includes a substrate and a packaging layer. The TEC adjustment module is disposed on the substrate, the APD chip is disposed on the TEC adjustment module, and the first thermistor is disposed on the TEC adjustment module and disposed next to the APD chip.

5. A method for temperature control of an APD package, based on the APD package according to any one of claims 1 to 4, characterized in that, Includes the following steps: Two sets of thermistors are configured in the APD package, and the two sets of thermistors are defined as the first thermistor and the second thermistor, respectively. The first thermistor is placed inside the APD package and adjacent to the APD chip to detect the temperature of the APD chip. The second thermistor is placed inside the APD package and used to detect the ambient temperature outside the APD chip; The temperature information collected by the first thermistor and the second thermistor is output and fed back. The temperature difference is calculated based on the output feedback from the first and second thermistors, and then the temperature is adjusted by the TEC adjustment module based on the temperature difference calculation result.

6. The APD packaging temperature control method according to claim 5, characterized in that, The first thermistor and the second thermistor adopt a synchronous sampling mechanism, and obtain the product temperature and ambient temperature respectively through the corresponding sampling circuit.

7. The APD packaging temperature control method according to claim 5, characterized in that, The conversion formula between the temperature information and resistance value of the first and second thermistors is as follows: Where T is the current temperature of the first thermistor or the second thermistor; T0 is the reference temperature of the first or second thermistor; B is the material constant of the first or second thermistor; R is the resistance value of the first or second thermistor at the current temperature; R0 is the resistance value of the first or second thermistor at temperature T0.

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