Universal calibration method for single-ended mode and differential mode of resistance-capacitance hybrid SAR-ADC

Abstract

The invention discloses a universal calibration method for a single-ended mode and a differential mode of a resistance-capacitance hybrid SAR-ADC, and belongs to the field of chips. The invention relates to a general calibration method for a single-ended mode and a differential mode of a resistance-capacitance hybrid SAR-ADC. The general calibration method comprises the following steps: step 1, configuring a single-ended calibration mode or a differential calibration mode; 2, outputting a digital code; step 3, obtaining an offset; step 4, configuring the SAR-ADC into a single-ended conversion mode or a differential mode; step 5, single-ended conversion mode calibration is carried out; step 6, differential mode calibration is carried out; and 7, adjusting the conversion ending mark to be the highest, and ending the conversion. According to the invention, the problem that mismatch in a single-ended mode and a differential mode of the SAR-ADC is easily caused and the calibration accuracy is influenced in the prior art is solved, and the static capacitance mismatch circuit is suitable for the static capacitance mismatch problem of the high-precision SAR-ADC, so that the requirements of various application scenes are met.

Description

Technical Field

[0001] The present invention relates to the field of chip technology, and in particular to a universal calibration method for single-ended mode and differential mode of a resistor-capacitor hybrid SAR-ADC. Background Art

[0002] Traditional SAR-ADCs typically use large binary capacitor arrays, resulting in significant waste of area and power. Therefore, practical designs often employ segmented capacitors or mixed resistor-capacitor architectures. Component mismatching in SAR-ADCs often leads to errors, primarily from two sources: first, capacitor mismatch degrades the linearity of the capacitor array, thereby affecting the linearity of the SAR-ADC; second, mismatched MOS transistors in the comparator cause input offset errors. Calibration is essential for improving SAR-ADC conversion accuracy.

[0003] The Chinese patent publication number CN116707527A discloses a SAR-ADC capacitor array calibration method and circuit, comprising the following steps: (1) in calibration mode, the high-order capacitor of the capacitor array DAC in the SAR-ADC samples the reference voltage, and then the low-order capacitor quantizes the high-order capacitor, and calculates the weight error of the high-order capacitor as the error compensation code based on the quantization result and stores it; (2) in normal working mode, the SAR-ADC completes the sampling and quantization of the input analog signal, extracts the error compensation code of the weight bit that needs to be compensated for the weight error based on the comparator result in the SAR-ADC, calculates the total compensation value, and adds it to the uncalibrated output result output by the SAR-ADC to obtain the calibrated output result. Without measuring the comparator noise, the weight error of the capacitor array DAC can be accurately measured.

[0004] Since SAR-ADCs are divided into single-ended mode and differential mode, the above-mentioned patent cannot perform corresponding calibration when the SAR-ADC is in different modes during actual use. This can easily lead to mismatch between the SAR-ADC single-ended mode and differential mode, affecting the calibration accuracy. Therefore, this patent does not meet existing needs. In response to this, we propose a universal calibration method for single-ended and differential modes of RC hybrid SAR-ADCs. Summary of the Invention

[0005] The present invention aims to provide a universal calibration method for single-ended and differential modes of a hybrid resistor-capacitor SAR-ADC. This method can significantly improve the performance of the SAR-ADC while optimizing the calibration process, reducing resource and time consumption, ensuring the reliability and efficiency of the SAR-ADC in different application scenarios, reducing the time and resources required for calibration, and achieving a low-complexity, high-efficiency calibration process. The method is not only applicable to the static capacitance mismatch problem of high-precision SAR-ADCs, but can also effectively address the multivariate and complex errors introduced by high-speed, high-precision SAR-ADCs, thereby meeting the needs of various application scenarios and solving the problems raised in the above-mentioned background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a universal calibration method for single-ended and differential modes of a RC hybrid SAR-ADC, comprising the following steps: Step 1: Build a hybrid RC SAR-ADC architecture, power on the SAR-ADC properly, activate the SAR-ADC, and configure the single-ended calibration mode or differential calibration mode after the SAR-ADC is activated. Step 2: After the configuration is completed, the single-ended mode or differential mode calibration mode is obtained, and the digital code of the single-ended mode or differential mode calibration mode is output; Step 3: Calculate the difference between the single-ended mode or differential mode calibration theoretical value and the digital code obtained in step 2 to obtain the offset; Step 4: Write the offset to the single-ended mode calibration register or the differential mode calibration register, and configure the SAR-ADC to single-ended conversion mode or differential mode. Step 5: When single-ended conversion mode is required, write the offset to the calibration compensation during the SAR-ADC sampling phase, and perform the calibration compensation during the conversion phase; Step 6: When differential mode is required, the offset is written to the calibration compensation during the SAR-ADC sampling phase, and the calibration compensation is performed during the conversion phase. Step 7: Finally, adjust the conversion end flag of the SAR-ADC to the highest level and the conversion ends.

[0007] Preferably, the resistor-capacitor hybrid SAR-ADC architecture specifically includes: SAR logic module, used to provide a binary search algorithm and output a digital signal to be calibrated; RC hybrid DAC, used to convert digital signals into analog signals while achieving a trade-off between area and performance; A dynamic comparator is used to compare the input voltage with the reference voltage through a RC hybrid DAC and a dynamic comparator; An output register, which implements successive approximation according to the result of the dynamic comparator, and outputs a converted or calibrated digital code; A calibration compensation module is used to compensate and offset the offset using a digital signal processing algorithm; The ADC controller is used to provide enable signals and data processing for the SAR-ADC in various operating modes.

[0008] Preferably, the working process of the dynamic comparator includes: Compare the voltage at the input terminal with the reference voltage. When the voltage at the input terminal is higher than the reference voltage, the comparator outputs high-level data. The voltage at the input terminal is compared with the reference voltage. When the voltage at the input terminal is lower than the reference voltage, the comparator outputs low-level data.

[0009] Preferably, the working process of the output register includes: Data enters the register from the input end and is temporarily stored in the register composed of flip-flops. Each flip-flop can store one bit of binary data. When data output is required, the data is output bit by bit from an output terminal in a serial form, and the moving direction and speed of the data are controlled according to the output requirements of the data.

[0010] Preferably, the working process of the ADC controller specifically includes: Convert the analog quantity that changes continuously in time into a series of equally spaced pulses, the amplitude of which depends on the input analog quantity; After sampling, the obtained sample pulse amplitude is maintained. After the input analog signal voltage is sampled and held, a step wave is obtained. The quantized digital signal is encoded and converted into a discrete signal represented by a binary value after encoding.

[0011] Preferably, the working process of the RC hybrid DAC specifically includes: The input digital signal is read regularly through a clock signal of a certain frequency to obtain a series of discrete digital samples; Mapping the sampled digital samples to a finite level, and converting the digital samples into corresponding analog levels according to a preset quantization step size; The quantized analog level is converted into a form suitable for output, and the current source circuit structure is used to realize the conversion from level to voltage and current.

[0012] Preferably, the working process of the calibration compensation module includes: During the calibration phase, the error caused by capacitor mismatch is compensated by measuring the error voltage value and storing the result in the output register; In normal working mode, the SAR-ADC completes the sampling and quantization of the input analog signal, extracts the error compensation code of the weight bit that needs to be compensated for the weight error based on the comparator result in the SAR-ADC, calculates the total compensation value, and adds it to the uncalibrated output result of the SAR-ADC to obtain the calibrated output result.

[0013] Preferably, the single-ended mode calibration specifically includes the following steps: After the SAR-ADC is powered on, SAR-ADCenable is enabled to configure the SAR-ADC mode to single-ended calibration mode; The single-ended calibration mode will calibrate 0V based on VCM to obtain the calibration output digital code, and then subtract the single-ended calibration mode output digital code from the single-ended mode calibration theoretical value in the ADC controller to obtain the offset and store it in the single-ended mode calibration register; When the SAR-ADC performs single-ended conversion, the ADC controller writes the offset data in the single-ended mode calibration register to the calibration compensation of the SAR-ADC to implement each single-ended mode AD conversion calibration.

[0014] Preferably, the differential mode calibration specifically includes the following steps: After the SAR-ADC is powered on, SAR-ADCenable is used to configure the SAR-ADC mode to differential calibration mode. The differential calibration mode converts the differential 0V based on VCM to obtain the calibration output digital code. The differential calibration mode output digital code and the differential mode calibration theoretical value are subtracted in the ADC controller to obtain the offset and stored in the differential mode calibration register. When the SAR-ADC performs differential conversion, the ADC controller sends the offset data Double in the differential mode calibration register to the SAR-ADC calibration compensation to achieve calibration for each differential mode conversion. Preferably, calculating the difference between the single-ended mode or differential mode calibration theoretical value and the digital code obtained in step 2 to obtain the offset specifically includes: Determine the input signal type: You need to determine whether the input signal is single-ended or differential. ‌Theoretical value calculation‌: Calculate the theoretical output value based on the type of input signal; ‌Actual measurement‌: The voltage value of the input signal is actually measured through the SAR-ADC and recorded; ‌Calculate the difference‌: Compare the actual measured voltage value with the theoretically calculated value and calculate the difference, which is the offset.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention performs universal calibration on a resistor-capacitor hybrid SAR-ADC, significantly improving the performance of the SAR-ADC. It also optimizes the calibration process, reduces resource and time consumption, ensures the reliability and efficiency of the SAR-ADC in different application scenarios, reduces the time and resources required for calibration, and implements a low-complexity, high-efficiency calibration process. The present invention is not only applicable to the static capacitance mismatch problem of high-precision SAR-ADCs, but can also effectively address the multivariate and complex errors introduced by high-speed, high-precision SAR-ADCs. The effective number of bits of the SAR-ADC after calibration is always maintained at a high level, thus meeting the needs of various application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the calibration method of the present invention; Figure 2 This is a schematic diagram of the architecture of the RC hybrid SAR-ADC of the present invention; Figure 3 Schematic diagram of the connection of the resistor-capacitor hybrid SAR-ADC architecture of the present invention. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] To solve the problem that the existing technology cannot perform corresponding calibration according to the mode, which easily leads to mismatch between the SAR-ADC single-ended mode and differential mode, affecting the calibration accuracy, please refer to Figure 1-Figure 3 , this embodiment provides the following technical solutions: A universal calibration method for single-ended and differential modes of a RC hybrid SAR ADC includes the following steps: Step 1: Build a hybrid RC SAR-ADC architecture, power on the SAR-ADC properly, activate the SAR-ADC, and configure the single-ended calibration mode or differential calibration mode after the SAR-ADC is activated. Step 2: After the configuration is completed, the single-ended mode or differential mode calibration mode is obtained, and the digital code of the single-ended mode or differential mode calibration mode is output; Step 3: Calculate the difference between the single-ended mode or differential mode calibration theoretical value and the digital code obtained in step 2 to obtain the offset; Step 4: Write the offset to the single-ended mode calibration register or differential mode calibration register in the ADC controller, and configure the SAR-ADC to single-ended conversion mode or differential mode. This allows the SAR-ADC to be powered on again and directly call the data in the single-ended mode calibration register during the conversion phase without going through the calibration process. Step 5: When single-ended conversion mode is required, write the offset to the calibration compensation during the SAR-ADC sampling phase, and perform the calibration compensation during the conversion phase; Step 6: When differential mode is required, the offset is written to the calibration compensation during the SAR-ADC sampling phase, and the calibration compensation is performed during the conversion phase. Step 7: Finally, adjust the conversion end flag of the SAR-ADC to the highest level and the conversion ends.

[0019] It can effectively reduce the nonlinear error of the SAR-ADC and improve the performance of the SAR-ADC. It uses error self-calibration technology to calibrate the high-capacitance mismatch error of the resistor-capacitor hybrid SAR-ADC. It can accurately adjust and compensate for the error of the SAR-ADC, thereby reducing the nonlinear error, improving the accuracy and performance of the SAR-ADC, and improving the signal-to-noise ratio. The signal quality is higher, the linearity of the SAR-ADC is guaranteed, and the output is more stable and reliable. Better performance indicators can be obtained, such as lower differential nonlinearity error and integral nonlinearity error, as well as a high signal-to-noise ratio, thereby improving the performance indicators of the SAR-ADC.

[0020] The RC hybrid SAR-ADC architecture includes: SAR logic module, used to provide a binary search algorithm and output a digital signal to be calibrated; RC hybrid DACs are used to convert digital signals into analog signals while achieving a trade-off between area and performance, allowing signals in digital systems to be recognized by the outside world (such as humans or other non-digital systems). The design of a RC hybrid DAC combines resistors and capacitors to achieve high-precision and high-performance conversion. This design approach can optimize circuit area and cost while ensuring signal quality, thereby achieving a trade-off between area and performance. A dynamic comparator is used to compare the input voltage with the reference voltage through a RC hybrid DAC and a dynamic comparator; An output register, which implements successive approximation according to the result of the dynamic comparator, and outputs a converted or calibrated digital code; A calibration and compensation module is used to compensate and offset the offset using a digital signal processing algorithm; The ADC controller is used to provide enable signals and data processing for the SAR-ADC in various operating modes.

[0021] The working process of the dynamic comparator includes: Compare the voltage at the input terminal with the reference voltage. When the voltage at the input terminal is higher than the reference voltage, the comparator outputs high-level data. Compare the voltage at the input with a reference voltage. When the voltage at the input is lower than the reference voltage, the comparator outputs low-level data. Dynamic comparators can complete voltage comparisons in a very short time, which makes them very suitable for systems that require fast decision-making. They consume less energy during operation, which can extend the overall service life of the equipment and reduce energy consumption.

[0022] The working process of the output register includes: Data enters the register from the input end and is temporarily stored in the register composed of flip-flops. Each flip-flop can store one bit of binary data. When data output is required, the data is output bit by bit in a serial manner from one output port, and the direction and speed of data movement are controlled according to the data output requirements. This process can be from high to low or left shift or from low to high or right shift. The serial output method saves the number of output ports and reduces costs, but the speed is relatively slow. The use of output registers can improve data processing efficiency. Accessing data through registers avoids the delay of accessing memory, which can reduce the time required to process data, thereby improving overall processing efficiency. The use of output registers can also reduce the burden on the CPU, ensuring that the system can process input and generate output in a timely manner without delays due to waiting for memory access.

[0023] The working process of the ADC controller includes: Converts a continuously changing analog quantity into a series of equally spaced pulses, whose amplitudes depend on the input analog quantity. This process adheres to the Nyquist sampling theorem, which states that the sampled value can accurately reflect the original analog signal only when the sampling frequency is greater than twice the highest frequency component in the analog signal. After sampling, the obtained sample pulse amplitude is maintained. After the input analog signal voltage is sampled and held, a step wave is obtained for conversion. This is because the sampling pulse width is generally very short. Before the next sampling pulse arrives, the obtained sample pulse amplitude should be temporarily maintained. Quantization is to divide the sample value into different levels according to certain standards, and each level corresponds to a digital value. The quantized digital signal is encoded and converted into a discrete signal represented by a binary value after encoding, completing the conversion from analog to digital, so that the digital system can understand and process these signals. By converting the external analog signal into digital form, various measurement, detection and control applications can be realized.

[0024] The working process of the RC hybrid DAC includes: The input digital signal is read regularly through a clock signal of a certain frequency to obtain a series of discrete digital samples.

[0025] The sampled digital samples are mapped to a finite level and converted into corresponding analog levels according to a preset quantization step size.

[0026] The quantized analog level is converted into a form suitable for output, and the level-to-voltage or current conversion is achieved using a resistor network or current source circuit structure. The RC hybrid DAC achieves high-quality conversion of digital signals to analog signals by combining resistors and capacitors, while optimizing the circuit area and cost, further improving the accuracy and reliability of the conversion.

[0027] The working process of the calibration compensation module includes: During the calibration phase, the error caused by capacitor mismatch is compensated by measuring the error voltage value and storing the result in the output register; In normal operating mode, the SAR-ADC completes the sampling and quantization of the input analog signal; Extract the error compensation code of the weight bit that needs to be compensated for weight error according to the comparator result in the SAR-ADC; The total compensation value is calculated and added to the uncalibrated output of the SAR-ADC to obtain the calibrated output.

[0028] Single-ended mode calibration includes the following steps: After the SAR-ADC is powered on, SAR-ADCenable is enabled to configure the SAR-ADC mode to single-ended calibration mode; The single-ended calibration mode will calibrate 0V based on VCM to obtain the calibration output digital code, and then subtract the single-ended calibration mode output digital code from the single-ended mode calibration theoretical value in the ADC controller to obtain the offset and store it in the single-ended mode calibration register; When the SAR-ADC performs single-ended conversion, the ADC controller writes the offset data in the single-ended mode calibration register to the calibration compensation of the SAR-ADC to implement each single-ended mode AD conversion calibration.

[0029] In single-ended mode, the SAR-ADC is calibrated to improve accuracy, maintain circuit performance flexibility, and optimize the input structure, making the resistor-capacitor hybrid SAR-ADC a high-precision, high-performance analog-to-digital converter.

[0030] Differential mode calibration includes the following steps: After the SAR-ADC is powered on, SAR-ADCenable is used to configure the SAR-ADC mode to differential calibration mode. The differential calibration mode converts the differential 0V based on VCM to obtain the calibration output digital code. The differential calibration mode output digital code and the differential mode calibration theoretical value are subtracted in the ADC controller to obtain the offset and stored in the differential mode calibration register. When the SAR-ADC performs differential conversion, the ADC controller sends the offset data Double in the differential mode calibration register to the SAR-ADC calibration compensation to achieve calibration for each differential mode conversion. Calibrating the SAR-ADC in differential mode can effectively expand the dynamic range of the input signal, allowing the SAR-ADC to more accurately capture and process a wider range of input signals, reduce non-ideal effects such as parasitic capacitance and charge injection, and improve conversion accuracy and stability. It can also simplify phase control, reduce complexity, and maintain high-performance analog-to-digital conversion.

[0031] Calculate the difference between the single-ended mode or differential mode calibration theoretical value and the digital code obtained in step 2 to obtain the offset, which includes: Determine the input signal type: First, determine whether the input signal is single-ended or differential. Single-ended input has only one input pin, while differential input has two input pins, one for the positive input and the other for the negative input.

[0032] Theoretical value calculation: Calculates the theoretical output value based on the input signal type, single-ended or differential. For single-ended input, the theoretical output value is directly equal to the input voltage; for differential input, the theoretical output value is equal to the positive input voltage minus the negative input voltage.

[0033] ‌Actual measurement‌: The voltage value of the input signal is actually measured through the SAR-ADC and recorded.

[0034] Calculate the difference: Compare the actual measured voltage value with the theoretically calculated value and calculate the difference, which is the offset. This difference is the deviation between the actual measured value and the theoretical value. This can effectively calculate the difference between the calibration theoretical value and the actual measured value in single-ended mode or differential mode, i.e., the offset, to calibrate and optimize the system or device.

[0035] In summary, the universal calibration method for single-ended and differential modes of a RC hybrid SAR ADC of the present invention can significantly improve the performance of the SAR ADC, including accuracy, stability, and signal detection capability, by performing universal calibration on the RC hybrid SAR ADC. At the same time, it optimizes the calibration process, reduces resource and time consumption, ensures the reliability and efficiency of the SAR ADC in different application scenarios, reduces the time and resources required for calibration, and implements a low-complexity, high-efficiency calibration process. This method is not only applicable to the static capacitance mismatch problem of high-precision SAR ADCs, but can also effectively address the multivariate and complex errors introduced by high-speed, high-precision SAR ADCs, ensuring that the effective number of bits of the calibrated SAR ADC remains at a high level under different frequency input signals, thereby meeting the needs of various application scenarios.

[0036] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0037] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the scope and spirit of the invention.

Claims

1. A universal calibration method for single-ended and differential modes of a hybrid SAR-ADC, characterized in that: The following steps are involved: Step 1: Build a hybrid SAR-ADC architecture, activate the SAR-ADC, and configure the single-ended calibration mode or differential calibration mode after the SAR-ADC is activated; Step 2: After the configuration is completed, a single-ended mode or differential mode calibration mode is obtained, and a digital code of the single-ended mode or differential mode calibration mode is output; Step 3: Calculate the difference between the single-ended mode or differential mode calibration theoretical value and the digital code obtained in step 2 to obtain the offset; Step 4: Write the offset to the single-ended mode calibration register or the differential mode calibration register, and configure the SAR-ADC to the single-ended conversion mode or the differential mode; Step 5: When single-ended conversion mode is required, write the offset to the calibration compensation during the SAR-ADC sampling phase, and the calibration compensation works during the conversion phase; Step 6: When the differential mode is required, the differential mode writes the offset to the calibration compensation during the SAR-ADC sampling phase, and the calibration compensation works during the conversion phase; Step 7: Adjust the conversion end flag of SAR-ADC to the highest level and the conversion ends.

2. The universal calibration method for single-ended mode and differential mode of a RC hybrid SAR-ADC according to claim 1, characterized in that: The RC hybrid SAR-ADC architecture specifically includes: SAR logic module, used for providing a binary search algorithm and outputting a digital signal to be calibrated; RC hybrid DAC, used to convert digital signals into analog signals while achieving a trade-off between area and performance; A dynamic comparator is used to compare an input voltage with a reference voltage through a RC hybrid DAC and a dynamic comparator; An output register, which implements successive approximation according to the result of the dynamic comparator, and the output register outputs a conversion or calibration digital code; A calibration compensation module is used to compensate and offset the offset using a digital signal processing algorithm; The ADC controller is used to provide the enable signal and data processing of the SAR-ADC in various working modes.

3. The universal calibration method for single-ended mode and differential mode of a RC hybrid SAR-ADC according to claim 2, characterized in that: The working process of the dynamic comparator includes: Compare the voltage at the input terminal with the reference voltage. When the voltage at the input terminal is higher than the reference voltage, the comparator outputs high-level data. The voltage at the input terminal is compared with the reference voltage. When the voltage at the input terminal is lower than the reference voltage, the comparator outputs low level data.

4. The universal calibration method for single-ended mode and differential mode of a RC hybrid SAR-ADC according to claim 2, characterized in that: The working process of the output register includes: Data enters the register from the input end and is temporarily stored in a register composed of flip-flops, each of which stores one bit of binary data; When data output is required, the data is output bit by bit from an output terminal in a serial form, and the moving direction and speed of the data are controlled according to the output requirements of the data.

5. The universal calibration method for single-ended mode and differential mode of a RC hybrid SAR-ADC according to claim 2, characterized in that: The working process of the ADC controller specifically includes: Convert the analog quantity that changes continuously in time into a series of equally spaced pulses, the amplitude of which depends on the input analog quantity; After sampling, the obtained sample value pulse amplitude is maintained, and the input analog signal voltage is sampled and held to obtain a step wave; The quantized digital signal is encoded, and after encoding is completed, it is converted into a discrete signal represented by a binary value.

6. The universal calibration method for single-ended mode and differential mode of a RC hybrid SAR-ADC according to claim 2, characterized in that: The working process of the RC hybrid DAC specifically includes: The input digital signal is read regularly through a clock signal of a certain frequency to obtain discrete digital samples; Mapping the sampled digital samples to a finite level, and converting the digital samples into corresponding analog levels according to a preset quantization step size; The quantized analog level is converted into a form suitable for output, and the level to voltage and current conversion is realized using the current source circuit structure.

7. The universal calibration method for single-ended mode and differential mode of a RC hybrid SAR-ADC according to claim 2, characterized in that: The working process of the calibration compensation module includes: During the calibration phase, the error caused by capacitor mismatch is compensated by measuring the error voltage value and storing the result in the output register. In normal operating mode, the SAR-ADC completes the sampling and quantization of the input analog signal; Extract the error compensation code of the weight bit that needs to be compensated for weight error according to the dynamic comparator result in the SAR-ADC; The total compensation value is calculated and added to the uncalibrated output of the SAR-ADC to obtain the calibrated output.

8. The universal calibration method for single-ended mode and differential mode of a RC hybrid SAR-ADC according to claim 1, characterized in that: The single-ended mode calibration specifically includes the following steps: After the SAR-ADC is powered on, SAR-ADCenable is used to configure the SAR-ADC mode to the single-ended calibration mode; The single-ended calibration mode will calibrate 0V based on VCM to obtain the calibration output digital code, and then make a difference between the single-ended calibration mode output digital code and the single-ended mode calibration theoretical value in the ADC controller to obtain the offset, and store it in the single-ended mode calibration register; When the SAR-ADC performs single-ended conversion, the ADC controller writes the offset data in the single-ended mode calibration register to the calibration compensation of the SAR-ADC to achieve each single-ended mode AD conversion calibration.

9. The universal calibration method for single-ended mode and differential mode of a RC hybrid SAR-ADC according to claim 1, characterized in that: The differential mode calibration specifically comprises the following steps: After the SAR-ADC is powered on, SAR-ADCenable is used to configure the SAR-ADC mode to the differential calibration mode; The differential calibration mode converts the differential 0V based on VCM to obtain the calibration output digital code, and the differential calibration mode output digital code and the differential mode calibration theoretical value are subtracted in the ADC controller to obtain the offset, which is stored in the differential mode calibration register; When the SAR-ADC performs differential conversion, the ADC controller sends the offset data Double in the differential mode calibration register to the calibration compensation of the SAR-ADC to achieve calibration for each differential mode conversion.

10. The universal calibration method for single-ended mode and differential mode of a RC hybrid SAR-ADC according to claim 1, characterized in that: The step of calculating the difference between the single-ended mode or differential mode calibration theoretical value and the digital code obtained in step 2 to obtain the offset specifically includes: ‌Determine the input signal type‌: It is necessary to determine whether the input signal is single-ended input or differential input; ‌Theoretical value calculation‌: Calculate the theoretical output value according to the type of input signal; ‌Actual measurement‌: The voltage value of the input signal is actually measured through the SAR-ADC and recorded; ‌Calculate the difference‌: Compare the actual measured voltage value with the theoretical calculated value and calculate the difference, which is the offset.

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