A low-power charge measurement method and system for radiation-hardened image sensors

Abstract

This invention discloses a low-power charge measurement method and system for radiation-resistant image sensors, relating to the field of charge measurement technology for image sensors. The method includes: capturing a charge signal and storing it in a charge storage capacitor via a timing-controllable sampling switch; closing a readout switch after disconnecting the sampling switch; converting the charge signal into a voltage signal whose duration is monotonically correlated with the amount of charge to be measured via a speed-adjustable discharge circuit, with the discharge speed adaptively adjusted according to the amount of charge; transmitting the shaped signal remotely to a safe area far from the radiation environment via a radiation-resistant system; measuring the signal duration at the remote location and converting it into the amount of charge to be measured via a pre-calibrated lookup table. This invention deploys a high-precision quantization stage at a remote location, eliminating the need for ultra-high-speed digital components and complex radiation-resistant hardening at the front end, significantly reducing front-end power consumption. Simultaneously, the adaptive discharge balances measurement speed and accuracy, effectively resolving the contradiction between radiation resistance, low power consumption, high speed, and high accuracy in charge measurement under strong radiation environments.

Description

Technical Field

[0001] This invention relates to the field of image sensor charge measurement technology, and specifically to a low-power charge measurement method and system for radiation-resistant image sensors. Background Technology

[0002] Image sensors (based on common electronic technologies such as CMOS) are core devices used in fields such as nuclear industry, high-energy physics, and explosion mechanics to capture rapidly changing optical images. They convert incident light into charge signals through photoelectric sensing materials, and then convert them into readable digital values ​​through charge measurement circuits. Currently, mainstream digital charge measurement systems complete signal conversion in three steps: sampling, storage, and measurement, enabling continuous high-precision measurement. The technology based on switched capacitor arrays has further improved the system measurement speed under limited image buffer capacity. However, in environments with strong radiation and severe shock and vibration, such as inside nuclear fusion devices, nuclear reactors, and explosion sites, traditional charge measurement schemes have many unsolvable problems: To protect precision digital components from radiation damage, physical shielding methods such as metal mesh are usually used, which blocks incident light, resulting in darkened images, increased noise, and severely reduced imaging quality; To reduce the power consumption of the front-end circuit to improve integration, the only way is to reduce sensor resolution, measurement speed, and accuracy, which cannot meet the requirements of high-speed and high-precision measurement; At the same time, traditional schemes integrate high-precision quantization circuits and front-end sampling circuits in the same irradiation area. A large number of high-speed digital components not only bring extremely high instantaneous power consumption, but are also highly susceptible to radiation-induced errors such as single-event upsets and total dose effects, leading to distorted measurement results or even system failure. Furthermore, the fixed-speed charge discharge method cannot adjust the rate according to the amount of charge to be measured. When measuring large amounts of charge, the discharge time is too long and the digitization readout speed is too slow. When measuring small amounts of charge, the discharge is too fast and the signal is easily submerged by noise, making it difficult to simultaneously meet the multiple requirements of radiation resistance, low power consumption, high speed, and high precision. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a low-power charge measurement method and system for radiation-resistant image sensors. By deploying the high-precision quantization stage at a remote location, the front end does not require ultra-high-speed digital components and complex radiation hardening, significantly reducing front-end power consumption. At the same time, adaptive discharge balances measurement speed and accuracy, effectively resolving the contradiction between radiation resistance, low power consumption, and high precision in charge measurement under strong radiation environments.

[0004] To achieve the above objectives, the embodiments of this invention provide the following technical solutions:

[0005] This application provides a low-power charge measurement method for radiation-resistant image sensors, comprising the following steps: S1, capturing the charge signal generated by the photoelectric conversion pixels at the front end of the image sensor and storing it in a charge storage capacitor by closing a sampling switch; S2, after opening the sampling switch, closing a readout switch, causing the charge storage capacitor to discharge current through a speed-adjustable bleeder circuit, converting the charge signal into a node b voltage signal whose duration is monotonically correlated with the amount of charge to be measured, wherein the discharge speed of the bleeder circuit is automatically controlled according to the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is opened, so that the larger the amount of charge to be measured... The faster the discharge speed, the more the voltage signal of node b is further shaped to obtain the node c1 signal or the node c2 signal; S3, the node c1 signal or the node c2 signal is converted into an optical signal or a wireless signal through an anti-radiation remote transmission circuit and transmitted to a remote safe area far away from the radiation environment; S4, the node c1 signal or the node c2 signal is received in the remote safe area, and the duration of the node c1 signal or the node c2 signal is converted into a digital code value through a high-precision quantization circuit, and then the digital measurement result of the charge to be measured is obtained according to the pre-calibrated monotonic correspondence between the duration and the charge.

[0006] Further, S2 further includes the following steps: S21, before the readout switch is closed, the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is open is driven into a control voltage through an additional control voltage buffer circuit; S22, after the readout switch is closed, the control voltage value is kept unchanged to control the grounding resistance value inside the leakage circuit or the total current output of the current source; S23, when the control voltage value is large, the grounding resistance value is reduced or the total current is increased to improve the charge discharge speed.

[0007] Furthermore, the leakage circuit in S2 includes a resistor, inductor, capacitor network or fixed current source structure; the shaping of the voltage signal at node b is achieved by using a high-speed digital discrimination circuit or a specific frequency carrier mixing circuit to convert the analog charge information into time length information.

[0008] Furthermore, the radiation-resistant remote transmission circuit in S3 adopts a wired transmission structure or a wireless transmission structure. The wired transmission structure includes an electro-optical conversion module, an optical fiber, and an optical-electrical conversion module. The wireless transmission structure includes a transmitting antenna and a receiving antenna.

[0009] Furthermore, the high-precision quantization circuit in S4 employs a high-precision time-to-digital conversion circuit or a high-precision waveform digitization circuit combined with a digital waveform time extraction algorithm.

[0010] Furthermore, the pre-calibrated monotonic correspondence between the duration and charge in S4 is stored in the form of a lookup table, the capacity of which matches the number of bits N of the quantization circuit and is 2 to the power of N.

[0011] Further, the measurement of the duration of the node c1 signal in S4 is performed using the following steps: S41, the received node c1 voltage signal is edge-shaped by a high-speed digital discrimination circuit to obtain a digital pulse signal; S42, the time when the rising edge of the node c1 voltage signal reaches a first fixed threshold is measured and denoted as t1, and the time when the falling edge of the node c1 voltage signal reaches a second fixed threshold is measured and denoted as t2; S43, the absolute value of the difference between t1 and t2 is expressed as the duration of the node c1 signal.

[0012] Further, the measurement of the duration of the node c2 signal in S4 adopts the following sub-steps: S401, based on a reference signal with the same frequency as the carrier signal, the received node c2 carrier signal is down-converted to obtain the envelope signal of the carrier signal, and the envelope signal is edge-shaped by a high-speed digital discrimination circuit to obtain an envelope pulse signal; S402, the time when the rising edge of the envelope signal reaches the first fixed threshold is measured and recorded as t3, and the time when the falling edge of the envelope signal reaches the second fixed threshold is measured and recorded as t4; S403, the absolute value of the difference between t3 and t4 is expressed as the duration of the node c2 signal.

[0013] Accordingly, this application also provides a low-power charge measurement system for radiation-resistant image sensors, including: a sampling and storage circuit configured to capture and store charge signals generated by photoelectric conversion pixels at the front end of the image sensor into a charge storage capacitor by closing a sampling switch; and an output shaping circuit configured to close a readout switch after the sampling switch is opened, causing the charge storage capacitor to discharge current through a speed-adjustable bleed circuit, converting the charge signal into a node b voltage signal whose duration is monotonically related to the amount of charge to be measured. The discharge speed of the bleed circuit is automatically controlled based on the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is opened, so that the larger the amount of charge to be measured, the faster the discharge speed. After further shaping the node b voltage signal, a node c1 signal or a node c1 signal is obtained. c2 signal; Radiation-resistant remote transmission circuit, the input of which is connected to the output of the output shaping circuit, and configured to convert the node c1 signal or node c2 signal into an optical signal or a wireless signal through the radiation-resistant remote transmission circuit, and transmit it to a remote safe area far from the radiation environment; High-precision quantization circuit, located in the remote safe area, the input of which is connected to the output of the radiation-resistant remote transmission circuit, and configured to receive the node c1 signal or node c2 signal in the remote safe area, and convert the duration of the node c1 signal or node c2 signal into a digital code value through the high-precision quantization circuit, and then obtain the digital measurement result of the charge to be measured according to the pre-calibrated monotonic correspondence between the duration and the charge.

[0014] The beneficial effects of this invention are as follows: By separating the high-precision quantization stage from the front end and deploying it in a safe, remote area, the front end does not need to integrate high-speed digital components and high-precision quantization circuits that are susceptible to radiation, fundamentally solving the problem of radiation interference with high-precision measurements, while significantly reducing front-end power consumption and radiation resistance costs; by adaptively adjusting the charge discharge rate, it achieves a balance between rapid measurement of large charge quantities and high-precision measurement of small charge quantities, effectively expanding the dynamic range of the system; and by radiation-resistant remote transmission, it ensures reliable signal transmission in strong radiation environments, avoiding signal distortion during transmission. Attached Figure Description

[0015] Figure 1 A schematic flowchart illustrating a low-power charge measurement method for radiation-resistant image sensors provided in this application embodiment;

[0016] Figure 2 A typical structural diagram of a low-power charge measurement system for radiation-resistant image sensors provided in this application embodiment;

[0017] Figure 3This application provides a schematic diagram of the structure of two typical bleed circuits in a low-power charge measurement system for radiation-resistant image sensors.

[0018] Figure 4 for Figure 2 A schematic diagram of monitoring the signal characteristics and timing of key nodes in the middle;

[0019] Figure 5 A schematic diagram of an alternative structure for an output shaping circuit of a low-power charge measurement system for a radiation-resistant image sensor, provided in an embodiment of this application;

[0020] Figure 6 This is a schematic diagram of a low-power charge measurement system for radiation-resistant image sensors, provided as an embodiment of this application. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0022] In this invention, the terms "system" and "network" are used interchangeably. "Multiple" refers to two or more; therefore, in this invention, "multiple" can also be understood as "at least two." "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / ", unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship. Furthermore, it should be understood that in the description of this invention, terms such as "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or order.

[0023] Example 1:

[0024] like Figure 1 , 4As shown, this application provides a low-power charge measurement method for radiation-resistant image sensors, including the following steps: S1, by closing a sampling switch, capturing the charge signal generated by the photoelectric conversion pixel at the front end of the image sensor and storing it in a charge storage capacitor; S2, after opening the sampling switch, closing the readout switch, causing the charge storage capacitor to discharge current through a speed-adjustable bleeder circuit, converting the charge signal into a node b voltage signal whose duration is monotonically related to the amount of charge to be measured, wherein the discharge speed of the bleeder circuit is automatically controlled according to the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is opened, so that the amount of charge to be measured... The larger the voltage, the faster the discharge speed. After further shaping the voltage signal of node b, the node c1 signal or node c2 signal is obtained; S3, the node c1 signal or node c2 signal is converted into an optical signal or wireless signal through an anti-radiation remote transmission circuit and transmitted to a remote safe area far away from the radiation environment; S4, the node c1 signal or node c2 signal is received in the remote safe area, and the duration of the node c1 signal or node c2 signal is converted into a digital code value through a high-precision quantization circuit. Then, according to the pre-calibrated monotonic correspondence between the duration and the charge, the digital measurement result of the charge to be measured is obtained.

[0025] In another possible embodiment, the closing of a low-power analog sampling switch, whose on / off timing is precisely controlled by an external timing signal, is first used to quickly capture the charge signal generated by the photoelectric sensing material of the image sensor under incident light. This charge signal is then stored in a small charge storage capacitor for temporary storage of the induced charge. After the sampling process is complete, the sampling switch is opened to isolate the image sensor from the subsequent charge readout circuit, preventing subsequent charge generation from interfering with the stored signal. Subsequently, a readout switch, also controlled by an external timing signal, is closed, allowing the charge storage capacitor to discharge current through a speed-adjustable bleeder circuit according to a preset pattern. During this process, the discharge speed of the bleeder circuit is automatically controlled based on the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is opened, ensuring that the larger the amount of charge to be measured, the faster the discharge speed. This converts the charge signal stored in the capacitor into a signal whose duration is monotonically positively correlated with the amount of charge to be measured. The voltage signal of node b is related to the duration of the voltage signal, which refers to the length of time during which the voltage signal value is greater than a certain threshold. The node b voltage signal is then sent to a shaping circuit for further shaping, converting the analog voltage signal into a node c1 or node c2 signal suitable for remote transmission. The shaped node c1 or node c2 signal is then sent to a radiation-resistant remote transmission circuit, which converts the electrical signal into a more radiation-resistant optical signal or a wireless carrier signal modulated by a special frequency. The signal is then transmitted through a corresponding transmission medium to a remote, safe area far from strong radiation and shock environments. Finally, the transmitted signal is received in the remote, safe area, and the duration of the signal is measured by a high-precision quantization circuit deployed in the safe area. This duration is converted into a corresponding digital code value. Based on a pre-defined correspondence between the duration and the charge, the final digital measurement result of the measured charge is obtained. It should be specifically noted that... Figure 4 Node 'a' in the diagram represents the charge information buffered by the charge storage capacitor after the sampling switch is opened and the readout switch is closed.

[0026] By separating the high-precision quantization process from the front end and deploying it in a remote, safe area, the front end no longer needs to integrate high-speed digital components and high-precision quantization circuits that are susceptible to radiation. This fundamentally solves the problem of radiation interference with high-precision measurements, while significantly reducing front-end power consumption and radiation resistance costs. By adaptively adjusting the charge discharge rate, both rapid measurement with large charge quantities and high-precision measurement with small charge quantities are achieved, effectively expanding the dynamic range of the system. Radiation-resistant remote transmission ensures reliable signal transmission in strong radiation environments, avoiding signal distortion during transmission.

[0027] In an embodiment of this application, step S2 further includes the following steps: S21, before the readout switch is closed, the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is open is driven to be converted into a control voltage through an additional control voltage buffer circuit; S22, after the readout switch is closed, the control voltage value output by the control voltage buffer circuit is kept unchanged, and is used to control the grounding resistance value inside the leakage circuit or the total current output by the current source; S23, when the control voltage value is large, the grounding resistance value is reduced or the total current is increased to improve the charge discharge speed.

[0028] In another possible embodiment, before the readout switch is closed, an additional control voltage buffer circuit converts the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is open into a control voltage. This control voltage value is proportional to the amount of charge to be measured stored in the charge storage capacitor, accurately reflecting the magnitude of the charge to be measured. After the control voltage buffer is complete, the readout switch is closed. At this time, the control voltage buffer circuit maintains a constant output voltage value, unaffected by subsequent voltage changes in the charge storage capacitor. This constant control voltage value is input as a control signal to the bleeder circuit to control the grounding resistance value or the total output current of the current source within the bleeder circuit. When the buffered control voltage value is large, i.e., the amount of charge to be measured is large, the control signal will decrease the grounding resistance value of the bleeder circuit or increase the total output current of the current source, thereby increasing the charge discharge speed and shortening the measurement time for large charge signals. When the buffered control voltage value is small, i.e., the amount of charge to be measured is small, the control signal will increase the grounding resistance value of the bleeder circuit or decrease the total output current of the current source, thereby reducing the charge discharge speed and avoiding signal overload caused by rapid discharge of small charge signals, ensuring the accuracy of small charge measurement.

[0029] By pre-caching the initial voltage value of the charge storage capacitor before the readout switch is closed and keeping the cached voltage unchanged after the readout switch is closed, this voltage is used as a reference voltage to control the discharge rate. This avoids the influence of the capacitor voltage drop on the discharge rate during the discharge process, ensuring a precise correspondence between the charge discharge rate and the amount of charge to be measured. This improves the accuracy and consistency of the charge signal to time signal conversion, laying the foundation for subsequent high-precision quantization.

[0030] In the embodiments of this application, the leakage circuit in S2 includes a resistor, inductor, capacitor network or fixed current source structure; the shaping of the voltage signal at node b is achieved by using a high-speed digital discrimination circuit or a specific frequency carrier mixing circuit to convert the analog charge information into time length information.

[0031] In another possible embodiment, the discharge circuit can be selected with different structures according to actual needs. When the system power consumption requirement is high, a passive network structure composed of resistors, inductors, and capacitors can be used. The equivalent discharge resistance value of the network is adjusted by controlling the voltage to achieve speed-adjustable charge discharge. This structure does not require an additional power supply circuit, has extremely low power consumption, and is simple in structure. When the requirements for response speed and control accuracy are high, a fixed current source structure can be used. The discharge speed is adjusted by controlling the output current of the current source. This structure has a fast response speed and stable discharge current, enabling more precise speed control. The shaping process of the voltage signal at node b can also be selected with different circuits according to transmission requirements. When using wired long-distance optical fiber transmission, a... A high-speed digital discrimination circuit is used to compare the analog voltage signal of node b with a preset fixed threshold, and output a node c1 signal in the form of a pulse with clear edges. This signal has a simple structure and is convenient for subsequent time measurement. When using long-distance wireless transmission, a specific frequency carrier mixing circuit can be used to mix and modulate the voltage signal of node b (or the node c1 signal) with a carrier signal of a preset frequency to generate a high-frequency carrier signal carrying charge information, namely the node c2 signal. This signal has stronger anti-interference ability and can achieve reliable transmission in complex electromagnetic environments. Regardless of the circuit structure or the combination of high-speed digital discrimination circuit and specific frequency carrier mixing circuit, the duration of the output signal can be guaranteed to maintain a monotonically positive correlation with the amount of charge to be measured.

[0032] By providing a variety of optional bleedering and shaping circuit structures, the system can be flexibly selected and combined according to different power consumption requirements, response speed requirements, and transmission methods. Among them, the passive resistor-inductor-capacitor network bleedering circuit has the advantages of low power consumption and simple structure; the fixed current source bleedering circuit has the advantages of fast response speed and high control precision; the high-speed digital discrimination circuit can generate pulse signals with clear edges, which is suitable for long-distance high-speed fiber optic transmission; and the specific frequency carrier mixing circuit can generate carrier signals with strong anti-interference ability, which is suitable for long-distance high-speed fiber optic transmission and wireless transmission, thereby greatly improving the versatility and flexibility of the system.

[0033] In the embodiments of this application, the radiation-resistant remote transmission circuit in S3 adopts a wired transmission structure or a wireless transmission structure. The wired transmission structure includes an electro-optical conversion module, an optical fiber, and an optical-electrical conversion module. The wireless transmission structure includes a transmitting antenna and a receiving antenna.

[0034] In another possible embodiment, the radiation-resistant remote transmission circuit can choose between a wired or wireless transmission structure depending on the application scenario. When the application scenario allows for the laying of optical fiber and has high requirements for transmission speed and reliability, a wired transmission structure is adopted. This structure includes an electro-optical conversion module, an optical fiber, and an optical-electrical conversion module connected in sequence. The node c1 signal or node c2 signal output from the front end is first sent to the electro-optical conversion module, which converts the electrical signal into an optical signal. The optical signal is then transmitted through an optical fiber with excellent radiation resistance, which can completely shield electromagnetic interference, ensuring that the signal is not affected by radiation during transmission. Due to the influence of optical fiber, after being transmitted to the remote end, the optical signal is converted back into an electrical signal by the optical-to-electric conversion module and then sent to the subsequent high-precision quantization circuit. When the application scenario cannot lay optical fiber or requires mobile measurement, a wireless transmission structure is adopted. This structure includes a transmitting antenna, a receiving antenna, and a carrier modulation module. The signal output from the front end is first modulated by a carrier modulation module at a special frequency to improve the signal's anti-interference capability. Then, the modulated carrier signal is transmitted through the transmitting antenna. After the receiving antenna deployed in a safe area at the remote end receives the carrier signal, it is demodulated and restored to the original electrical signal, which is then sent to the high-precision quantization circuit for processing.

[0035] By providing two radiation-resistant long-distance transmission structures, the fiber-optic-based wired transmission structure is completely unaffected by electromagnetic interference and can achieve high-speed, lossless signal transmission in strong radiation environments. The carrier modulation-based wireless transmission structure can effectively resist electromagnetic interference caused by radiation and is suitable for mobile scenarios or long-distance transmission scenarios where fiber optic cables cannot be laid. Both structures can ensure the reliability of signal transmission from the irradiated area to the remote safe area and avoid signal loss and distortion during transmission.

[0036] In the embodiments of this application, the high-precision quantization circuit in S4 adopts a high-precision time-to-digital conversion circuit or a high-precision waveform digitization circuit combined with a digital waveform time extraction algorithm.

[0037] In another possible embodiment, the high-precision quantization circuit deployed in a remote, secure area can be selected from different types depending on the requirements for measurement accuracy and speed. When high accuracy and speed are required for time measurement, a high-precision time-to-digital conversion circuit is used. This circuit can directly measure the time interval between the rising and falling edges of the input signal and convert it into the corresponding digital code value, which has the advantages of fast measurement speed and high accuracy. When more detailed analysis or processing of carrier-modulated signals of the signal waveform is required, a high-precision waveform digitization circuit is used. This circuit can sample the input signal at high speed, convert the analog waveform into a digital waveform, and then extract the duration information of the signal through digital signal processing technology, which has stronger signal processing capabilities and flexibility. Both circuits are deployed in a safe environment with no or low radiation, and can work stably and output high-precision quantization results.

[0038] By deploying high-precision quantization circuits in a safe, remote area away from radiation environments, no radiation hardening is required. Mature commercial high-precision quantization circuits can be directly used, which reduces circuit costs and power consumption, fully utilizes the high-precision advantages of existing technologies, ensures the accuracy of quantization results, avoids the impact of radiation effects on quantization circuits, and improves the long-term stability of the system.

[0039] In the embodiments of this application, the pre-calibrated monotonic correspondence between the duration and the charge in step S4 is stored in the form of a lookup table, the capacity of which matches the number of bits N of the quantization circuit and is 2 to the power of N.

[0040] In another possible embodiment, the correspondence between the signal duration output by the output shaping circuit and the charge accumulated by the sampling and storage circuit is first precisely calibrated to obtain a set of one-to-one mapping data. Then, this set of mapping data is used to construct a high-precision lookup table that matches the bit depth N of the high-precision quantization circuit. The capacity of the lookup table is set to 2 to the power of N to cover all digital code values ​​that the quantization circuit can output, ensuring that the corresponding charge value can be found in the lookup table for each possible time length measurement result. In the actual measurement process, when the high-precision quantization circuit outputs the digital code value corresponding to the signal duration, the pre-constructed lookup table can be queried directly using the digital code value as an index to quickly obtain the corresponding charge value to be measured, thus completing the digital measurement of the charge.

[0041] By using a pre-calibrated lookup table to store the correspondence between duration and charge, the corresponding charge can be quickly obtained by directly indexing the lookup table using the digital code value corresponding to the measured duration during the quantization process. This eliminates the need for complex real-time calculations, significantly improving the system's response speed. At the same time, the pre-calibrated lookup table can eliminate errors caused by factors such as circuit nonlinearity, thus improving the accuracy of the measurement results.

[0042] In the embodiments of this application, the measurement of the duration of the node c1 signal in step S4 is performed using the following steps: S41, the received node c1 voltage signal is edge-shaped by a high-speed digital discrimination circuit to obtain a digital pulse signal; S42, the time when the rising edge of the node c1 voltage signal reaches a first fixed threshold is measured and denoted as t1, and the time when the falling edge of the node c1 voltage signal reaches a second fixed threshold is measured and denoted as t2; S43, the absolute value of the difference between t1 and t2 is expressed as the duration of the node c1 signal.

[0043] In another possible embodiment, for the node c1 pulse signal shaped by the high-speed digital discrimination circuit, the received node c1 voltage signal is first sent to the high-speed digital discrimination circuit for further edge shaping to obtain a digital pulse signal with steeper and clearer edges. Then, the high-precision time measurement module is activated to capture the moment when the rising edge of the digital pulse signal reaches a preset first fixed threshold and records this moment as t1. Then, the signal change is monitored to capture the moment when the falling edge of the digital pulse signal reaches a preset second fixed threshold and records this moment as t2. Finally, the absolute value of the difference between the two moments t1 and t2 is calculated. This absolute value is the duration of the node c1 signal. The first and second fixed thresholds can be reasonably set according to the signal level characteristics to suppress noise interference to the maximum extent.

[0044] By employing a dual-threshold measurement method, the time when the rising edge of the signal reaches the first fixed threshold and the time when the falling edge reaches the second fixed threshold are measured separately. The difference between the two times is used as the duration of the signal. This effectively suppresses measurement errors caused by signal noise and level fluctuations. At the same time, combined with the high-speed digital discrimination circuit for accurate capture of signal edges, the accuracy of the duration measurement of the node c1 signal is greatly improved.

[0045] In the embodiments of this application, the measurement of the duration of the node c2 signal in step S4 is performed using the following sub-steps: S401, based on a reference signal with the same frequency as the carrier signal, the received node c2 carrier signal is down-converted to obtain the envelope signal of the carrier signal, and the envelope signal is edge-shaped by a high-speed digital discrimination circuit to obtain an envelope pulse signal; S402, the time when the rising edge of the envelope signal reaches a first fixed threshold is measured and recorded as t3, and the time when the falling edge of the envelope signal reaches a second fixed threshold is measured and recorded as t4; S403, the absolute value of the difference between t3 and t4 is expressed as the duration of the node c2 signal.

[0046] In another possible embodiment, for the node c2 carrier signal obtained by the carrier mixer circuit at a specific frequency, a local reference signal with the same frequency as the carrier signal is first generated. Then, the received node c2 carrier signal and the local reference signal are sent together to the downconversion circuit for synchronous downconversion processing to filter out the high-frequency carrier component and obtain a low-frequency envelope signal that reflects the change of the original charge signal. Next, the envelope signal is sent to the high-speed digital discrimination circuit for edge shaping processing to obtain an envelope pulse signal with clear edges. Then, the high-precision time measurement module is activated to capture the moment when the rising edge of the envelope pulse signal reaches the first fixed threshold and record this moment as t3. The signal change is monitored to capture the moment when the falling edge of the envelope pulse signal reaches the second fixed threshold and record this moment as t4. Finally, the absolute value of the difference between the two moments t3 and t4 is calculated. This absolute value is the duration of the node c2 signal.

[0047] By converting the high-frequency carrier signal into a low-frequency envelope signal through synchronous downconversion, the influence of the carrier's frequency fluctuations and phase noise on the measurement is eliminated. Then, the duration is extracted from the envelope signal using a dual-threshold measurement method, which can accurately restore the time length information corresponding to the original charge signal and ensure the accuracy of the carrier modulation signal measurement.

[0048] Example 2:

[0049] like Figure 2 , 3As shown in Figures 5 and 6, embodiments of this application also provide a low-power charge measurement system for radiation-resistant image sensors, comprising: a sampling and storage circuit configured to capture charge signals generated by photoelectric conversion pixels at the front end of the image sensor and store them in a charge storage capacitor by closing a sampling switch; and an output shaping circuit configured to close a readout switch after the sampling switch is opened, causing the charge storage capacitor to discharge current through a speed-adjustable bleed circuit, converting the charge signal into a node b voltage signal whose duration is monotonically correlated with the amount of charge to be measured, wherein the discharge speed of the bleed circuit is automatically controlled according to the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is opened, so that the larger the amount of charge to be measured, the faster the discharge speed; and after further shaping the node b voltage signal, a node c1 signal or... Node c2 signal; Radiation-resistant remote transmission circuit, the input of which is connected to the output of the output shaping circuit, and configured to convert the node c1 signal or node c2 signal into an optical signal or a wireless signal through the radiation-resistant remote transmission circuit, and transmit it to a remote safe area far from the radiation environment; High-precision quantization circuit, located in the remote safe area, the input of which is connected to the output of the radiation-resistant remote transmission circuit, and configured to receive the node c1 signal or node c2 signal in the remote safe area, and convert the duration of the node c1 signal or node c2 signal into a digital code value through the high-precision quantization circuit, and then obtain the digital measurement result of the charge to be measured according to the pre-calibrated monotonic correspondence between the duration and the charge.

[0050] In another possible embodiment, the system includes four core modules connected in sequence: a sampling and storage circuit, an output shaping circuit, a radiation-resistant remote transmission circuit, and a high-precision quantization circuit. The front-end portions of the sampling and storage circuit, the output shaping circuit, and the radiation-resistant remote transmission circuit are deployed in an environment with strong radiation and shock vibration, while the high-precision quantization circuit is deployed in a remote, safe area far from the radiation environment. The sampling and storage circuit consists of a timing-controllable sampling switch and a charge storage capacitor, configured to capture the charge signal generated by the photoelectric conversion pixels at the front end of the image sensor by closing the sampling switch and store it in the charge storage capacitor, thus completing the sampling and storage of the charge signal. The output shaping circuit consists of a timing-controllable readout switch, a speed-adjustable bleeder circuit, and a shaping circuit, configured to close the readout switch after the sampling switch is opened, causing the charge storage capacitor to discharge current through the bleeder circuit, converting the charge signal into a duration. The node b voltage signal, whose length is monotonically correlated with the amount of charge to be measured, is converted into a node c1 or node c2 signal suitable for remote transmission by a shaping circuit. The input of the radiation-resistant remote transmission circuit is connected to the output of the output shaping circuit and is configured to convert the node c1 or node c2 signal into an optical signal or a wireless carrier signal and transmit it to a remote safe area through the corresponding transmission medium. The input of the high-precision quantization circuit is connected to the output of the radiation-resistant remote transmission circuit and is configured to receive the transmitted signal in the remote safe area, measure the duration of the signal and convert it into a digital code value. Then, according to the pre-calibrated monotonically correlated relationship between the duration and the amount of charge, the digital measurement result of the amount of charge to be measured is obtained. The modules are connected through standardized electrical interfaces, and different sub-modules can be flexibly replaced according to actual needs to adapt to different application scenarios.

[0051] By adopting a modular and separate design, the high-precision quantization circuit, which is susceptible to radiation, is deployed in a remote and safe area. The front end retains only simple analog circuits and transmission circuits with strong radiation resistance, which significantly reduces the overall power consumption, size, and radiation resistance cost of the system. At the same time, the modules are connected through standardized interfaces, which can flexibly replace and combine different circuit structures according to different application requirements, improving the system's versatility and scalability. Furthermore, the physical separation of the front end and the back end effectively avoids mutual interference between modules, improving the system's stability and measurement accuracy.

[0052] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0053] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.

[0054] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. A low-power charge measurement method for radiation-resistant image sensors, characterized in that, Includes the following steps: S1. By closing the sampling switch, capture the charge signal generated by the photoelectric conversion pixel at the front end of the image sensor and store it in the charge storage capacitor; S2. After disconnecting the sampling switch, close the readout switch to allow the charge storage capacitor to discharge current through the speed-adjustable discharge circuit, converting the charge signal into a node b voltage signal whose duration is monotonically related to the amount of charge to be measured. The discharge speed of the discharge circuit is automatically controlled according to the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is disconnected, so that the larger the amount of charge to be measured, the faster the discharge speed. After further shaping the node b voltage signal, a node c1 signal or a node c2 signal is obtained. S3. Convert the node c1 signal or node c2 signal into an optical signal or a wireless signal through a radiation-resistant remote transmission circuit, and transmit it to a remote safe area far from the radiation environment. S4. Receive the node c1 signal or node c2 signal in the remote safe area, and convert the duration of the node c1 signal or node c2 signal into a digital code value through a high-precision quantization circuit. Then, based on the pre-calibrated monotonic correspondence between the duration and the charge, obtain the digital measurement result of the charge to be measured.

2. The low-power charge measurement method for radiation-resistant image sensors according to claim 1, characterized in that, S2 further includes the following steps: S21. Before the readout switch is closed, the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is opened is driven to be converted into a control voltage through an additional control voltage buffer circuit. S22. After the readout switch is closed, the control voltage value output by the control voltage buffer circuit remains unchanged, which is used to control the grounding resistance value inside the leakage circuit or the total current output by the current source. S23. When the control voltage value is large, reduce the grounding resistance value or increase the total current to improve the charge discharge speed.

3. The low-power charge measurement method for radiation-resistant image sensors according to claim 2, characterized in that, The leakage circuit in S2 includes a resistor, inductor, capacitor network or a fixed current source structure; the shaping of the voltage signal at node b is achieved by using a high-speed digital discrimination circuit or a carrier mixing circuit at a specific frequency point to convert the analog charge information into time length information.

4. The low-power charge measurement method for radiation-resistant image sensors according to claim 1, characterized in that, The radiation-resistant remote transmission circuit in S3 adopts a wired transmission structure or a wireless transmission structure. The wired transmission structure includes an electro-optical conversion module, an optical fiber, and an optical-electrical conversion module. The wireless transmission structure includes a transmitting antenna and a receiving antenna.

5. The low-power charge measurement method for radiation-resistant image sensors according to claim 1, characterized in that, The high-precision quantization circuit in S4 employs a high-precision time-to-digital conversion circuit or a high-precision waveform digitization circuit combined with a digital waveform time extraction algorithm.

6. The low-power charge measurement method for radiation-resistant image sensors according to claim 1, characterized in that, The pre-calibrated monotonic correspondence between the duration and charge in S4 is stored in the form of a lookup table. The capacity of the lookup table matches the number of bits N of the quantization circuit, which is 2 to the power of N.

7. The low-power charge measurement method for radiation-resistant image sensors according to claim 1, characterized in that, The measurement of the duration of the node c1 signal in S4 is performed using the following steps: S41. The received node c1 voltage signal is processed by edge shaping through a high-speed digital discrimination circuit to obtain a digital pulse signal; S42. Measure the time when the rising edge of the voltage signal of node c1 reaches the first fixed threshold, and record it as t1; and measure the time when the falling edge of the voltage signal of node c1 reaches the second fixed threshold, and record it as t2. S43. The absolute value of the difference between t1 and t2 is expressed as the duration of the node c1 signal.

8. The low-power charge measurement method for radiation-resistant image sensors according to claim 1, characterized in that, The measurement of the duration of the node c2 signal in S4 is performed using the following sub-steps: S401. Based on a reference signal with the same frequency as the carrier signal, the received node c2 carrier signal is down-converted to obtain the envelope signal of the carrier signal. The envelope signal is then edge-shaped by a high-speed digital discrimination circuit to obtain an envelope pulse signal. S402. Measure the time when the rising edge of the envelope pulse signal reaches the first fixed threshold, and record it as t3; and measure the time when the falling edge of the envelope signal reaches the second fixed threshold, and record it as t4. S403, The absolute value of the difference between t3 and t4 is expressed as the duration of the signal of node c2.

9. A low-power charge measurement system for radiation-resistant image sensors, characterized in that, The low-power charge measurement method for radiation-resistant image sensors as described in any one of claims 1 to 8 includes: The sampling and storage circuit is configured to capture the charge signal generated by the photoelectric conversion pixel at the front end of the image sensor and store it in the charge storage capacitor by closing the sampling switch; The output shaping circuit is configured to close the readout switch after the sampling switch is turned off, so that the charge storage capacitor discharges current through the speed-adjustable bleed circuit, converting the charge signal into a node b voltage signal whose duration is monotonically related to the amount of charge to be measured. The discharge speed of the bleed circuit is automatically controlled according to the voltage value on the surface of the charge storage capacitor at the moment the sampling switch is turned off, so that the larger the amount of charge to be measured, the faster the discharge speed. After further shaping the node b voltage signal, a node c1 signal or a node c2 signal is obtained. The radiation-resistant remote transmission circuit has its input terminal connected to the output terminal of the output shaping circuit and is configured to convert the node c1 signal or node c2 signal into an optical signal or a wireless signal through the radiation-resistant remote transmission circuit and transmit it to a remote safe area far away from the radiation environment. A high-precision quantization circuit is located in a remote safe area. The input of the high-precision quantization circuit is connected to the output of the radiation-resistant remote transmission circuit and is configured to receive the node c1 signal or the node c2 signal in the remote safe area. The high-precision quantization circuit converts the duration of the node c1 signal or the node c2 signal into a digital code value. Then, based on the pre-calibrated monotonic correspondence between the duration and the charge, the digital measurement result of the charge to be measured is obtained.

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