High-precision adc with thermal noise cancellation and implementation method

Abstract

This invention provides a thermal noise-cancelled high-precision ADC and its implementation method. The thermal noise-cancelled high-precision ADC includes a series of multi-stage circuits, where each single-stage circuit includes a sub-ADC, a DAC array, an auxiliary capacitor module, and an amplification module. The DAC array is used to sample the mixed voltage during the sampling stage. The auxiliary capacitor module is used to sample the input signal and, during the noise storage stage, provides a static bias voltage to all capacitors in the DAC array to separate the thermal noise voltage from the mixed voltage. The amplification module is used to amplify the thermal noise voltage during the noise storage stage and store the amplified thermal noise voltage. During the quantization and residual amplification stages, the amplified thermal noise voltage and its high gain characteristics are used to eliminate the thermal noise voltage. Based on the principle of charge conservation, the residual signal is amplified through charge transfer, and the amplified residual signal is used as the output voltage of the current single-stage circuit. This improves the accuracy of the pipelined ADC.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit design technology, and in particular to a thermal noise-canceling high-precision analog-to-digital converter (ADC) and its implementation method. Background Technology

[0002] Pipeline ADCs are widely used in communication systems, medical equipment, and testing instruments, where both speed and accuracy are critical. Pipeline ADCs achieve efficient analog-to-digital conversion through a multi-stage cascaded structure. Each cascaded stage, while performing quantization, amplifies the residual error and passes it to the next stage for further processing, thus achieving a balance between high sampling rate, high accuracy, and power consumption.

[0003] Currently, traditional pipelined ADCs use two non-overlapping first and second clock signals in their single-stage circuits. When the first clock signal is high, the single-stage circuit samples the input signal. When the second clock signal is high, the sub-ADC in this single-stage circuit quantizes the input signal, obtaining the quantized result. Using the digital output code corresponding to the quantized result, the digital-to-analog converter (DAC) array in this single-stage circuit is controlled to provide feedback, subtracting the quantized result from the input signal. The residual difference is then amplified to obtain the amplified residual signal, which is output from the single-stage circuit. However, due to the influence of electron thermal motion, the sampling operation introduces sampling thermal noise, affecting the quality of the amplified residual signal and resulting in lower accuracy for traditional pipelined ADCs. Summary of the Invention

[0004] The purpose of this invention is to provide a thermal noise cancellation type high-precision ADC and its implementation method, which solves the problem of low accuracy of the single-stage circuit of traditional pipeline ADCs.

[0005] To address the aforementioned technical problems, the embodiments of the present invention provide the following technical solutions:

[0006] The first aspect of the present invention provides a thermal noise cancellation type high-precision ADC, which includes a series multi-stage circuit, wherein each single-stage circuit includes a sub-ADC, a DAC array, an auxiliary capacitor module and an amplification module;

[0007] A DAC array is used to sample a mixed voltage during the sampling phase, the mixed voltage including the input voltage and the introduced thermal noise voltage;

[0008] The auxiliary capacitor module, connected to both the DAC array and the sub-ADC, is used to sample the input signal and, during the noise storage phase, provides a static bias voltage to all capacitors in the DAC array to separate thermal noise voltage from the mixed voltage. The auxiliary capacitors in the auxiliary capacitor module... The capacitance value is greater than the capacitance value of each capacitor in the DAC array;

[0009] The amplification module, connected to the DAC array, is used to amplify the thermal noise voltage during the noise storage stage and store the amplified thermal noise voltage. During the quantization and residual amplification stages, the amplified thermal noise voltage and high gain characteristics are used to eliminate the thermal noise voltage.

[0010] Sub-ADC is used to quantize the input signal and generate digital output code;

[0011] The DAC array is also used to switch the reference voltage in response to the digital output code to generate a residual signal;

[0012] The amplification module is also used to amplify the residual signal through charge transfer based on the principle of charge conservation, output the amplified residual signal, and use the amplified residual signal as the output voltage of the current single-stage circuit. The amplified residual signal is also used as the input signal of the next single-stage circuit.

[0013] A second aspect of the present invention provides a method for implementing a thermal noise cancellation type high-precision ADC, comprising:

[0014] During the sampling phase, a mixed voltage is sampled, which includes the input voltage and the introduced thermal noise voltage.

[0015] The input signal is sampled, and during the noise storage phase, a static bias voltage is provided to all capacitors in the DAC array to separate the thermal noise voltage from the mixed voltage.

[0016] During the noise storage stage, the thermal noise voltage is amplified and the amplified thermal noise voltage is stored.

[0017] During the quantization and residual amplification stages, the amplified thermal noise voltage and high gain characteristics are utilized to eliminate the thermal noise voltage.

[0018] The input signal is quantized to generate a digital output code;

[0019] In response to the digital output code, the reference voltage is switched to generate a residual signal;

[0020] Based on the principle of charge conservation, the residual signal is amplified through charge transfer, and the amplified residual signal is output. The amplified residual signal is used as the output voltage of the current single-stage circuit, and the amplified residual signal is used as the input signal of the next single-stage circuit.

[0021] Compared to existing technologies, the thermal noise-cancelling high-precision ADC provided by this invention includes a series of multi-stage circuits, wherein each single-stage circuit includes a sub-ADC, a DAC array, an auxiliary capacitor module, and an amplification module; the DAC array is used to sample a mixed voltage during the sampling phase, the mixed voltage including the input voltage and the introduced thermal noise voltage; the auxiliary capacitor module is connected to both the DAC array and the sub-ADC, used to sample the input signal, and during the noise storage phase, provides a static bias voltage to all capacitors in the DAC array to separate the thermal noise voltage from the mixed voltage; the auxiliary capacitor in the auxiliary capacitor module... The capacitance value of the auxiliary capacitor module is greater than that of each capacitor in the DAC array. The amplification module, connected to the DAC array, amplifies and stores the thermal noise voltage during the noise storage stage. During the quantization and residual amplification stages, it utilizes the amplified thermal noise voltage and its high gain to eliminate the thermal noise voltage. The sub-ADC quantizes the input signal to generate a digital output code. The DAC array also switches the reference voltage in response to the digital output code to generate a residual signal. The amplification module further amplifies the residual signal through charge transfer based on the principle of charge conservation, outputting the amplified residual signal as the output voltage of the current single-stage circuit. In this way, the auxiliary capacitor module provides a static bias voltage to all capacitors in the DAC array to separate the thermal noise voltage from the mixed voltage. The amplification module utilizes the amplified thermal noise voltage and its high gain to eliminate the separated thermal noise voltage, improving the accuracy of the pipelined ADC. Attached Figure Description

[0022] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein:

[0023] Figure 1 A schematic diagram of a thermal noise cancellation type high-precision ADC structure is shown.

[0024] Figure 2 The control timing diagram of a thermal noise-cancelling high-precision ADC is schematically shown.

[0025] Figure 3 A flowchart illustrating the implementation method of a thermal noise-cancelling high-precision ADC is shown. Detailed Implementation

[0026] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0027] It should be noted that, unless otherwise stated, the technical or scientific terms used in this invention should have the ordinary meaning as understood by one of ordinary skill in the art.

[0028] The methods described in the embodiments of the present invention will be explained in detail below.

[0029] Figure 1 A schematic diagram of a thermal noise cancellation type high-precision ADC structure is shown in an embodiment of the present invention. See [link / reference] Figure 1 As shown, a thermal noise cancellation type high-precision ADC can include a series of multi-stage circuits, wherein each single-stage circuit includes a sub-ADC, a DAC array, an auxiliary capacitor module, and an amplifier module;

[0030] A DAC array is used to sample a mixed voltage during the sampling phase, the mixed voltage including the input voltage and the introduced thermal noise voltage;

[0031] The auxiliary capacitor module, connected to both the DAC array and the sub-ADC, is used to sample the input signal and, during the noise storage phase, provides a static bias voltage to all capacitors in the DAC array to separate thermal noise voltage from the mixed voltage. The auxiliary capacitors in the auxiliary capacitor module... The capacitance value is greater than the capacitance value of each capacitor in the DAC array;

[0032] The amplification module, connected to the DAC array, is used to amplify the thermal noise voltage during the noise storage stage and store the amplified thermal noise voltage. During the quantization and residual amplification stages, the amplified thermal noise voltage and high gain characteristics are used to eliminate the thermal noise voltage.

[0033] Sub-ADC is used to quantize the input signal and generate digital output code;

[0034] The DAC array is also used to switch the reference voltage in response to the digital output code to generate a residual signal;

[0035] The amplification module is also used to amplify the residual signal by charge transfer according to the principle of charge conservation, output the amplified residual signal, and use the amplified residual signal as the output voltage of the current single-stage circuit. The amplified residual signal is also used as the input signal of the next single-stage circuit.

[0036] For example, taking the second single-stage circuit in a series multi-stage circuit as an example, the connection relationship of the second single-stage circuit is explained. The input terminal of the second single-stage circuit is connected to the output terminal of the first single-stage circuit, and the output terminal of the second single-stage circuit is connected to the input terminal of the third single-stage circuit.

[0037] Specifically, a series-connected multi-stage circuit comprises multiple single-stage circuits, where each subsequent single-stage circuit is connected to the next single-stage circuit. Each single-stage circuit in the series-connected multi-stage circuit generates a corresponding residual signal. The input signal of the first single-stage circuit is the initial input signal, while the inputs of all other single-stage circuits (excluding the first) use the residual signal generated by the previous stage as their input signal. For example, the input signal of the third single-stage circuit is the residual signal generated by the second single-stage circuit.

[0038] In a series-connected multi-stage circuit, each single-stage circuit generates a corresponding digital output code. After all the single-stage circuits have completed their operation, the digital output codes generated by each single-stage circuit are combined to obtain the final quantization result.

[0039] In this embodiment, the auxiliary capacitor module includes an auxiliary capacitor. and switch Auxiliary capacitor The bottom plate and common mode voltage Connection, auxiliary capacitor Top plate and switch One end of the switch is connected to the DAC array and the other end is connected to the switch. The other end is connected to one end of the sub-ADC and the other end of the DAC array.

[0040] In this embodiment, the DAC array includes multiple parallel sub-DAC units, each sub-DAC unit including a first switch. Second switch Third switch Fourth switch and the first capacitor First switch One end and the switch The other end and one end of the sub-ADC are both connected to the first switch. The other end is connected to the fourth switch One end, the first capacitor One end, the second switch One end, the third switch One end is connected to the fourth switch. The other end is connected to the auxiliary capacitor Top plate, switch One end of each capacitor is connected to the first capacitor. The other end is connected to one end of the amplification module, the second switch The other end is connected to the positive reference voltage. Connection, third switch The other end is connected to the negative reference voltage. connect.

[0041] Specifically, each sub-DAC unit has an identical structure, and the first switch of each sub-DAC unit is... All are composed of clock signals Control, fourth switch All are composed of clock signals Control, second switch and the third switch All are composed of clock signals control.

[0042] In this embodiment, the amplification module includes a noise storage capacitor. Feedback capacitor ,capacitance Preamplifier High-gain amplifier ,switch ,switch ,switch and switch ;switch One end is connected to the common-mode voltage Connection, switch The other end, the first capacitor The other end, preamplifier Input terminal and feedback capacitor One end of each is connected to endpoint X, preamplifier Output terminal and noise storage capacitor One end is connected to the noise storage capacitor. The other end is connected to a high-gain amplifier Input terminals, switches One end is connected to the switch. The other end is connected to the common-mode voltage. Connection, high-gain amplifier Output terminal and capacitor Top plate, output voltage ,switch One end of each capacitor is connected. The bottom plate is grounded, switch The other end is connected to the feedback capacitor One end, switch One end is connected to the switch. The other end is connected to the common-mode voltage. connect.

[0043] Specifically, the first switch in each sub-DAC unit and switch From clock signal Control. Fourth switch. and switch From clock signal Control. The second switch in each sub-DAC unit. Third switch and switch From clock signal Control. Switch From clock signal Control, switch From clock signal control.

[0044] In this embodiment, the preamplifier It is used to amplify the thermal noise voltage during the noise storage stage to generate an amplified thermal noise voltage.

[0045] Noise storage capacitor , used to store the amplified thermal noise voltage;

[0046] High gain amplifier This is used in the quantization and residual amplification stages to determine the preamplifier based on the amplified thermal noise voltage and high gain characteristics. The input voltage will be compared with the thermal noise voltage and the preamplifier. The voltages at the input terminals cancel each other out to eliminate sampling thermal noise.

[0047] Specifically, Figure 2 The control timing diagram of a thermal noise-cancelling high-precision ADC is schematically shown. See [link / reference]. Figure 2 As shown, one operating cycle of a thermal noise-cancelling high-precision ADC is divided into three stages: sampling stage, noise storage stage, and quantization and residual amplification stage. In the quantization and residual amplification stage of the previous cycle, the clock signal... Raise to high level, enabling auxiliary capacitor Sampling begins early. During the sampling phase of this cycle, the clock signal... The clock signal is raised to a high level, causing all capacitors in the DAC array to begin sampling; Raise to high level, causing the feedback capacitor Perform a reset operation to clear the charge. At the end of the sampling phase, the clock signal... and clock signal The clock signal drops to a low level. During the noise storage phase of this cycle, the clock signal... The voltage rises to a high level due to the auxiliary capacitor. The noise storage capacitor is connected in series with all the capacitors in the DAC array. The other end is connected to the common-mode voltage. auxiliary capacitor The auxiliary capacitor is connected in series with all the capacitors in the DAC array. A static voltage bias is provided for all capacitors in the DAC array, and the thermal noise voltage introduced by sampling appears at the other end of the DAC array capacitors. This thermal noise voltage introduced by sampling is preamplified. After amplification, it is stored in the noise storage capacitor. Up. At the end of the noise storage phase, the clock signal... and clock signal The voltage level drops to low. During the quantization and residual amplification phases of this cycle, the sub-ADC completes quantization, and the digital output code corresponding to the quantization result controls all switches in the DAC array to connect to different reference voltages (i.e., the positive reference voltage). and negative reference voltage The input signal and quantization result are subtracted; the amplified thermal noise voltage is stored in series in the preamplifier. The output terminal and the high-gain amplifier Between the input terminals; clock signal High-level amplifier When the switch connected to the output terminal is closed, the charge transfer is driven to complete the residual amplification process, which is unaffected by sampling thermal noise, in order to generate a residual signal.

[0048] The working principle of the thermal noise cancellation type high-precision ADC of this invention is as follows:

[0049] Traditional pipelined ADCs introduce sampling thermal noise during the sampling process. The thermal noise-canceling high-precision ADC of this invention can eliminate the sampling thermal noise introduced during the sampling process.

[0050] After the sampling phase, the total charge on all capacitors of the DAC array is:

[0051] ;

[0052] in, This represents the total charge on all capacitors in the DAC array. Input voltage, For the first in the DAC array The capacitance value of each capacitor. This represents the total capacitance of all capacitors in the DAC array. The charge is used to sample thermal noise.

[0053] Due to auxiliary capacitor The capacitance value of the auxiliary capacitor is greater than the capacitance value of each capacitor in the DAC array. Therefore, the thermal noise introduced by the sampling affects the auxiliary capacitor. The influence of the voltage at the top plate can be ignored in the subsequent analysis. (Auxiliary capacitor) The voltage value at the top plate is .

[0054] During the noise storage phase, the auxiliary capacitor The auxiliary capacitor is connected in series with all the capacitors in the DAC array. The voltage on the input provides a static bias voltage to the other end of all capacitors in the DAC array (i.e., the end closest to terminal X). The value of the static bias voltage is equal to the input voltage. If the voltage value is given, then the expression for the voltage at the other end of all capacitors in the DAC array (i.e., the thermal noise voltage) is:

[0055] ;

[0056] in, This is the thermal noise voltage. Input voltage, The total charge on the DAC array, For the first in the DAC array The capacitance value of each capacitor. This represents the total capacitance of all capacitors in the DAC array. The charge is used to sample thermal noise.

[0057] Thermal noise voltage Subsequently preamplified Amplified and stored in the noise storage capacitor. Up. Preamplifier The gain is Then the noise storage capacitor The stored voltage (i.e., the amplified thermal noise voltage stored above) is:

[0058] ;

[0059] in, This is the amplified thermal noise voltage.

[0060] During the residual amplification stage, the noise storage capacitor Connected in series with the preamplifier Output terminal and high gain amplifier The input terminal. Due to the high-gain amplifier The high impedance characteristic at the input terminal, noise storage capacitor The stored voltage information remains unchanged. This is due to the high-gain amplifier. High gain characteristics, high gain amplifier The voltage at the input terminal can be approximated as virtual ground. Therefore, the preamplifier The voltage at the output terminal also remains unchanged, which can be expressed as:

[0061] ;

[0062] The preamplifier can be calculated. The voltage at the input terminal is:

[0063] ;

[0064] in, For preamplifier The voltage at the input terminal, For preamplifier The voltage at the output terminal, For preamplifier Gain, To sample the charge of thermal noise, For the first in the DAC array The capacitance value of each capacitor. This represents the total capacitance of all capacitors in the DAC array. This is the amplified thermal noise voltage.

[0065] During the residual amplification stage, the digital output code generated by the sub-ADC controls the reference voltage connected to the DAC array. According to the principle of charge conservation, the output voltage of the current single-stage circuit of a thermally noise-cancelled high-precision ADC can be expressed as:

[0066] ;

[0067] in, This is the output voltage of the current single-stage circuit. For the first in the DAC array The capacitance value of each capacitor. This represents the total capacitance of all capacitors in the DAC array. Input voltage, For reference voltage, Generate codes for the numbers. For feedback capacitor The corresponding capacitance value.

[0068] The expression for the output voltage of the current single-stage circuit above does not contain a sampled thermal noise component; the sampled thermal noise is eliminated from the output of the single-stage circuit of the thermal noise-cancelled high-precision ADC.

[0069] The DAC array in this invention can sample mixed voltages and input signals. It utilizes a dual sampling technique and an auxiliary capacitor during the noise storage stage. It provides static bias voltage to all capacitors in the DAC array, avoiding the limitation of preamplifier output voltage saturation caused by the changing input signal in traditional sampling thermal noise cancellation technology, and widens the frequency range of the input signal to the Nyquist frequency, improving noise performance and better separating thermal noise voltage in mixed voltage.

[0070] Based on the above Figure 1 As can be seen from the implementation, the thermal noise cancellation high-precision ADC of this embodiment includes a series of multi-stage circuits, wherein each single-stage circuit includes a sub-ADC, a DAC array, an auxiliary capacitor module, and an amplification module; the DAC array is used to sample a mixed voltage during the sampling stage, the mixed voltage including the input voltage and the introduced thermal noise voltage; the auxiliary capacitor module is connected to both the DAC array and the sub-ADC, used to sample the input signal, and during the noise storage stage, provides a static bias voltage to all capacitors in the DAC array to separate the thermal noise voltage from the mixed voltage; the auxiliary capacitor in the auxiliary capacitor module... The capacitance value of the auxiliary capacitor module is greater than that of each capacitor in the DAC array. The amplification module, connected to the DAC array, amplifies and stores the thermal noise voltage during the noise storage stage. During the quantization and residual amplification stages, it utilizes the amplified thermal noise voltage and its high gain to eliminate the thermal noise voltage. The sub-ADC quantizes the input signal to generate a digital output code. The DAC array also switches the reference voltage in response to the digital output code to generate a residual signal. The amplification module further amplifies the residual signal through charge transfer based on the principle of charge conservation, outputting the amplified residual signal as the output voltage of the current stage circuit. The amplified residual signal is then used as the input signal for the next stage circuit. In this way, the auxiliary capacitor module provides a static bias voltage to all capacitors in the DAC array to separate the thermal noise voltage from the mixed voltage. The amplification module utilizes the amplified thermal noise voltage and its high gain to eliminate the separated thermal noise voltage, improving the accuracy of the pipelined ADC.

[0071] Based on the same inventive concept, as an implementation of the above-mentioned thermal noise cancellation high-precision ADC, the present invention also provides a method for implementing a thermal noise cancellation high-precision ADC.

[0072] Figure 3 This is a flowchart illustrating the implementation method of a thermal noise cancellation type high-precision ADC in an embodiment of the present invention. See [link / reference]. Figure 3 As shown, the implementation method of this thermal noise cancellation high-precision ADC may include:

[0073] S301. During the sampling phase, the mixed voltage is sampled.

[0074] The mixed voltage includes the input voltage and the introduced thermal noise voltage.

[0075] S302. Sample the input signal and, during the noise storage stage, provide a static bias voltage to all capacitors in the DAC array to separate the thermal noise voltage from the mixed voltage.

[0076] The expression for thermal noise voltage is:

[0077] ;

[0078] in, This is the thermal noise voltage. Input voltage, The total charge on the DAC array, For the first in the DAC array The capacitance value of each capacitor. This represents the total capacitance of all capacitors in the DAC array. The charge is used to sample thermal noise.

[0079] S303. During the noise storage stage, the thermal noise voltage is amplified and the amplified thermal noise voltage is stored.

[0080] S304. During the quantization and residual amplification stages, the thermal noise voltage is eliminated by utilizing the amplified thermal noise voltage and high gain characteristics.

[0081] Specifically, in the quantization and residual amplification stages, the amplified thermal noise voltage and high gain characteristics are utilized to eliminate thermal noise voltage, including:

[0082] Step A1: During the quantization and residual amplification stages, the voltage at the input of the preamplifier is determined by utilizing the amplified thermal noise voltage and high gain characteristics.

[0083] Among them, the preamplifier The expression for the voltage at the input terminal is:

[0084] ;

[0085] ;

[0086] in, For preamplifier The voltage at the input terminal, For preamplifier The voltage at the output terminal, For preamplifier Gain, To sample the charge of thermal noise, For the first in the DAC array The capacitance value of each capacitor. This represents the total capacitance of all capacitors in the DAC array. This is the amplified thermal noise voltage.

[0087] Step A2: The thermal noise voltage is canceled out by the voltage at the input of the preamplifier to eliminate sampling thermal noise.

[0088] S305 Quantizes the input signal to generate a digital output code.

[0089] Specifically, each single-stage circuit in a series-connected multi-stage circuit generates a corresponding digital output code. After all the single-stage circuits have completed their operation, the digital output codes generated by each single-stage circuit are combined to obtain the final quantization result.

[0090] S306, in response to the digital output code, switches the reference voltage to generate a residual signal.

[0091] S307. Based on the principle of charge conservation, the residual signal is amplified by charge transfer, and the amplified residual signal is output. The amplified residual signal is then used as the output voltage of the current single-stage circuit.

[0092] The amplified residual signal is used as the input signal for the next single-stage circuit.

[0093] The expression for the output voltage of the current single-stage circuit is as follows:

[0094] ;

[0095] in, This is the output voltage of the current single-stage circuit. For the first in the DAC array The capacitance value of each capacitor. This represents the total capacitance of all capacitors in the DAC array. Input voltage, For reference voltage, Output code for numbers. For feedback capacitor The corresponding capacitance value.

[0096] It should be noted that the above description of the implementation method of the thermal noise-canceling high-precision ADC is similar to the description of the thermal noise-canceling high-precision ADC embodiment described above, and has similar beneficial effects as those applicable to the thermal noise-canceling high-precision ADC embodiment. For technical details not disclosed in the embodiments of the implementation method of the thermal noise-canceling high-precision ADC of the present invention, please refer to the description of the thermal noise-canceling high-precision ADC embodiment of the present invention for understanding.

[0097] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A thermal noise cancellation type high-precision ADC, characterized in that, The thermal noise cancellation type high-precision ADC includes a series of multi-stage circuits, wherein each single-stage circuit includes a sub-ADC, a DAC array, an auxiliary capacitor module, and an amplification module; The DAC array is used to sample a mixed voltage during the sampling phase, the mixed voltage including the input voltage and the introduced thermal noise voltage; The auxiliary capacitor module, connected to both the DAC array and the sub-ADC, is used to sample the input signal and, during the noise storage phase, provides a static bias voltage to all capacitors in the DAC array to separate the thermal noise voltage from the mixed voltage. The auxiliary capacitor in the auxiliary capacitor module... The capacitance value is greater than the capacitance value of each capacitor in the DAC array; The amplification module is connected to the DAC array and is used to amplify the thermal noise voltage and store the amplified thermal noise voltage during the noise storage stage. During the quantization and residual amplification stage, the amplified thermal noise voltage and its high gain characteristics are used to eliminate the thermal noise voltage. The sub-ADC is used to quantize the input signal and generate a digital output code; The DAC array is also used to switch the reference voltage in response to the digital output code to generate a residual signal; The amplification module is also used to amplify the residual signal by charge transfer according to the principle of charge conservation, output the amplified residual signal, and use the amplified residual signal as the output voltage of the current single-stage circuit. The amplified residual signal is used as the input signal of the next single-stage circuit. The amplification module includes a noise storage capacitor. Feedback capacitor ,capacitance Preamplifier High-gain amplifier ,switch ,switch ,switch and switch ; The preamplifier It is used to amplify the thermal noise voltage during the noise storage stage to generate the amplified thermal noise voltage; The noise storage capacitor , used to store the amplified thermal noise voltage; The high-gain amplifier This is used in the quantization and residual amplification stages to determine the preamplifier using the amplified thermal noise voltage and the high-gain characteristics. The voltage at the input terminal, the thermal noise voltage and the preamplifier The voltages at the input terminals cancel each other out to eliminate sampling thermal noise; The high-gain amplifier Specifically, it is used in the residual amplification stage, where the noise storage capacitor... Connected in series in the preamplifier The output terminal and the high-gain amplifier The input terminal of the high-gain amplifier The high impedance characteristic of the input terminal, the noise storage capacitor The stored voltage information remains unchanged; due to the high-gain amplifier The high-gain characteristics of the high-gain amplifier The voltage at the input terminal is determined to be virtual ground; the preamplifier The voltage at the output terminal of the preamplifier also remains unchanged. The voltage at the output terminal is expressed as: ； The preamplifier The expression for the voltage at the input terminal is: ； in, For the preamplifier The voltage at the input terminal, For the preamplifier The voltage at the output terminal, For the preamplifier Gain, To sample the charge of thermal noise, For the DAC array of the first The capacitance value of each capacitor. This represents the total capacitance value of all capacitors in the DAC array. This refers to the amplified thermal noise voltage; During the residual amplification stage, the digital output code generated by the sub-ADC controls the reference voltage connected to the DAC array. According to the principle of charge conservation, the expression for the output voltage of the current single-stage circuit of the thermal noise cancellation high-precision ADC is: ； in, The output voltage of the current single-stage circuit. For the DAC array of the first The capacitance value of each capacitor. This represents the total capacitance value of all capacitors in the DAC array. The input voltage is... The reference voltage, Output code for numbers. The feedback capacitor The corresponding capacitance value; If the expression for the output voltage of the current single-stage circuit contains no sampled thermal noise component, then the sampled thermal noise is eliminated from the output of the single-stage circuit of the thermal noise-cancelling high-precision ADC.

2. The thermal noise cancellation type high-precision ADC according to claim 1, characterized in that, The auxiliary capacitor module includes the auxiliary capacitor. and switch The auxiliary capacitor The bottom plate and common mode voltage Connection, the auxiliary capacitor The top plate and the switch One end of the switch is connected to one end of the DAC array, and the other end of the switch is connected to the DAC array. The other end is connected to one end of the sub-ADC and the other end of the DAC array.

3. The thermal noise cancellation type high-precision ADC according to claim 2, characterized in that, The DAC array includes multiple parallel sub-DAC units, each sub-DAC unit including a first switch. Second switch Third switch Fourth switch and the first capacitor The first switch One end is connected to the switch The other end and one end of the sub-ADC are both connected to the first switch. The other end is connected to the fourth switch one end, the first capacitor One end, the second switch One end, the third switch One end of each is connected, the fourth switch The other end is connected to the auxiliary capacitor The top plate, the switch One end of each capacitor is connected to the first capacitor. The other end is connected to one end of the amplification module, and the second switch The other end is connected to the positive reference voltage. Connection, the third switch The other end is connected to the negative reference voltage. connect.

4. The thermal noise cancellation type high-precision ADC according to claim 3, characterized in that, The switch One end is connected to the common-mode voltage Connection, the switch The other end, the first capacitor The other end, the preamplifier The input terminal and the feedback capacitor One end of each preamplifier is connected to endpoint X. The output terminal and the noise storage capacitor One end is connected to the noise storage capacitor. The other end is connected to the high-gain amplifier The input terminal, the switch One end of each is connected, the switch The other end is connected to the common-mode voltage. Connection, the high-gain amplifier The output terminal and the capacitor The top plate, the output voltage The switch One end of each capacitor is connected to the capacitor. The bottom plate is grounded, and the switch The other end is connected to the feedback capacitor One end of the switch One end of each is connected, the switch The other end is connected to the common-mode voltage. connect.

5. The thermal noise cancellation type high-precision ADC according to claim 1, characterized in that, The expression for the thermal noise voltage is: ； in, The thermal noise voltage, The input voltage is... The total charge on the DAC array, For the DAC array of the first The capacitance value of each capacitor. This represents the total capacitance value of all capacitors in the DAC array. The charge is used to sample thermal noise.

6. A method for implementing a thermal noise-cancelling high-precision ADC, characterized in that, The thermal noise cancellation type high-precision ADC according to any one of claims 1-5 includes: During the sampling phase, a mixed voltage is sampled, which includes the input voltage and the introduced thermal noise voltage. The input signal is sampled, and during the noise storage phase, a static bias voltage is provided to all capacitors in the DAC array to separate the thermal noise voltage from the mixed voltage; During the noise storage phase, the thermal noise voltage is amplified and the amplified thermal noise voltage is stored. During the quantization and residual amplification stages, the amplified thermal noise voltage and high gain characteristics are used to eliminate the thermal noise voltage. The input signal is quantized to generate a digital output code; In response to the digital output code, the reference voltage is switched to generate a residual signal; According to the principle of charge conservation, the residual signal is amplified by charge transfer, and the amplified residual signal is output. The amplified residual signal is used as the output voltage of the current single-stage circuit, and the amplified residual signal is used as the input signal of the next single-stage circuit. In the quantization and residual amplification stage, the thermal noise voltage is eliminated by utilizing the amplified thermal noise voltage and high gain characteristics, including: During the quantization and residual amplification stage, the voltage at the input terminal of the preamplifier is determined using the amplified thermal noise voltage and the high gain characteristic. The thermal noise voltage is canceled out by the voltage at the input of the preamplifier to eliminate sampling thermal noise; In the quantization and residual amplification stage, the voltage at the input terminal of the preamplifier is determined using the amplified thermal noise voltage and the high-gain characteristic. The thermal noise voltage is then canceled out by the voltage at the input terminal of the preamplifier to eliminate sampling thermal noise. This includes: During the residual amplification stage, the noise storage capacitor Connected in series in the preamplifier The output terminal and the high-gain amplifier The input terminal of the high-gain amplifier The high impedance characteristic of the input terminal, the noise storage capacitor The stored voltage information remains unchanged; due to the high-gain amplifier The high-gain characteristics of the high-gain amplifier The voltage at the input terminal is determined to be virtual ground; the preamplifier The voltage at the output terminal of the preamplifier also remains unchanged. The voltage at the output terminal is expressed as: ； The preamplifier The expression for the voltage at the input terminal is: ； in, For the preamplifier The voltage at the input terminal, For the preamplifier The voltage at the output terminal, For the preamplifier Gain, To sample the charge of thermal noise, For the DAC array of the first The capacitance value of each capacitor. This represents the total capacitance value of all capacitors in the DAC array. This refers to the amplified thermal noise voltage; During the residual amplification stage, the digital output code generated by the sub-ADC controls the reference voltage connected to the DAC array. According to the principle of charge conservation, the expression for the output voltage of the current single-stage circuit of the thermal noise cancellation high-precision ADC is: ； in, The output voltage of the current single-stage circuit. For the DAC array of the first The capacitance value of each capacitor. This represents the total capacitance value of all capacitors in the DAC array. The input voltage is... The reference voltage, Output code for numbers. The feedback capacitor The corresponding capacitance value; If the expression for the output voltage of the current single-stage circuit contains no sampled thermal noise component, then the sampled thermal noise is eliminated from the output of the single-stage circuit of the thermal noise-cancelling high-precision ADC.

Images