Piecewise linear quantization hybrid structure analog-to-digital converter with noise shaping function

Abstract

The invention discloses a piecewise linear quantization mixed structure analog-to-digital converter with a noise shaping function, and belongs to the field of analog-to-digital converters, the analog-to-digital converter comprises an input control circuit, a nonlinear quantization circuit, a noise shaping modulation circuit, an output control circuit and a digital decimation filter circuit, the control circuit samples an input signal; the non-linear quantization circuit determines a non-linear section where an input signal is located and provides reference voltage for the noise shaping modulation circuit; the noise shaping modulation circuit is used for performing noise shaping and fine quantization on an input signal; the output control circuit combines the two parts of quantization output and generates a high-speed low bit code stream; the digital decimation filter circuit receives a high-speed code stream and generates a high-precision digital code through decimation filtering; according to the technology provided by the invention, suitable nonlinear quantization characteristics are provided according to different signal characteristics, and meanwhile, higher quantization precision and a wider dynamic range can be realized.

Description

Technical Field

[0001] This invention relates to the field of analog-to-digital converter technology, and more particularly to a piecewise linear quantization hybrid analog-to-digital converter with noise shaping function. Background Technology

[0002] Analog-to-digital converters (ADCs) convert analog signals with continuous time and continuous values ​​into discrete digital signals. The main structures of ADCs are fully parallel, successive approximation, pipelined, and Sigma-Delta, each suitable for different application scenarios and accuracy requirements. Successive approximation ADCs utilize the "binary division" principle for quantization, resulting in a simple structure, but achieving high accuracy is difficult. Sigma-Delta ADCs consist of a Sigma-Delta modulator and a digital decimation filter, employing oversampling and noise shaping techniques to achieve high accuracy. Hybrid ADCs, such as those using zoom and noise-shaping successive approximation, combine successive approximation and Sigma-Delta structures, offering both low power consumption and high accuracy.

[0003] Traditional analog-to-digital converters (ADCs) mostly employ uniform quantization, where the quantization interval is evenly distributed across the full-scale range. The closer the signal is to the full-scale value, the higher the signal-to-noise ratio (SNR). Correspondingly, small signals have a lower SNR. However, for applications with large dynamic ranges, such as audio and image signals, ADCs using non-linear quantization, such as piecewise linear quantization, can use fine quantization intervals for small signals of interest to improve resolution and SNR, while using coarse quantization intervals for large signals to accommodate higher amplitudes. Thus, without changing the number of quantization bits, they can accurately capture weak signals while avoiding large signal overflow, ultimately achieving a higher dynamic range than linear ADCs.

[0004] Successive approximation analog-to-digital converters (ADCs) have a simple structure but limited accuracy and low dynamic range. Oversampling ADCs can achieve high accuracy, but their complex structure makes it difficult to directly implement nonlinear quantization, and their dynamic range is limited by the characteristics of uniform quantization. Hybrid ADCs that combine different structures have the potential to achieve a higher dynamic range through nonlinear quantization, but current research on hybrid ADCs rarely involves nonlinear quantization. Existing ADCs lack a technology that can achieve a higher dynamic range. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a piecewise linear quantization hybrid structure analog-to-digital converter with noise shaping function; by using noise shaping technology, hybrid structure and piecewise linear quantization technology, the accuracy of existing piecewise linear analog-to-digital converters is improved, and the dynamic range of existing analog-to-digital converters is extended.

[0006] To achieve the above objectives, the present invention provides a piecewise linear quantization hybrid analog-to-digital converter with noise shaping function, comprising: an input control circuit, a nonlinear quantization circuit, a noise shaping and modulation circuit, an output control circuit, and a digital decimation filter circuit.

[0007] The input control circuit, connected to the nonlinear quantization circuit and the noise shaping and modulation circuit, receives the original input signal, performs amplitude conversion, and controls the nonlinear quantization circuit and the noise shaping and modulation circuit to receive the input signal. The nonlinear quantization circuit, connected to the noise shaping and modulation circuit, receives the input signal and determines its nonlinear segment, thereby providing a reference signal for the noise shaping and modulation circuit. The noise shaping and modulation circuit oversamples the input signal and performs noise shaping and uniform fine quantization on the signal residual after nonlinear quantization based on the reference signal from the nonlinear quantization circuit, modulating the noise within the signal band to outside the signal band and outputting the segment code. The output control circuit, connected to the nonlinear quantization circuit and the noise shaping and modulation circuit, receives the output of the nonlinear quantization circuit and the noise shaping and modulation circuit, stores the digital code during the quantization process, and performs buffering, processing, and output. The digital decimation filter circuit, connected to the output control circuit, receives the high-speed digital code output by the output control circuit, filters out high-frequency noise outside the signal band generated by noise shaping, and converts it into a high-precision digital code.

[0008] As a further improvement of the present invention, the nonlinear quantization circuit uses a successive approximation structure for coarse quantization, including: This nonlinear digital-to-analog converter uses a nonlinear weighted capacitor array to achieve the nonlinear transfer characteristics of the circuit. Charge scaling is achieved by controlling the nonlinear capacitor array through an input thermometer code to generate a reference voltage. It includes two digital-to-analog conversion units, one for generating the starting reference signal of the nonlinear segment interval where the signal resides. and endpoint reference signal ; The comparator unit is used to connect the system input signal sampled by the input control circuit and the signal generated by the digital-to-analog converter in the nonlinear quantization circuit, and to compare the two. The successive approximation register uses logic circuits to implement the successive approximation algorithm, receives the output of the comparator, and controls the quantization circuit to complete the successive approximation quantization. A decoder is used to connect the successive approximation register and the nonlinear quantization circuit, and converts the output binary code of the successive approximation register, which controls the nonlinear quantization circuit, into thermometer code.

[0009] As a further improvement of the present invention, the noise shaping and modulation circuit includes: A filter is used to convert the quantization residual of the nonlinear quantization circuit into an integral signal, and input the integral signal to the quantizer for quantization. A quantizer performs one or more bits of quantization on the integral signal generated by the filter and outputs a high-speed digital code as a partial quantization result. A logic circuit is connected to the output control circuit and the digital-to-analog converter to control the digital-to-analog converter to output a feedback signal; A digital-to-analog converter, connected to the nonlinear quantization circuit, receives a reference signal generated by the nonlinear digital-to-analog converter and generates a feedback signal based on the reference signal under the control of the logic circuit.

[0010] As a further improvement of the present invention, the noise shaping and modulation circuit can use a Sigma-Delta structure or a noise shaping successive approximation structure. When the noise shaping and modulation circuit is implemented using a noise shaping successive approximation structure, the quantizer is a one-bit quantizer, i.e., a comparator, and the logic circuit is implemented as a successive approximation register. The quantizer and the logic circuit can be shared with the nonlinear quantization circuit. In this case, the first M bits of the output of the successive approximation register are segment codes, which are used to control the nonlinear quantization circuit, and the last N bits are intra-segment codes, which are used to control the noise shaping and modulation circuit.

[0011] As a further improvement of the present invention, the output control circuit includes: The segment code buffer unit is used to buffer and output the quantization result of the nonlinear quantization circuit during the quantization process; An intra-segment code buffer unit is used to buffer and output the quantization result of the noise shaping modulation circuit during the quantization process; The arithmetic logic unit is used to integrate the quantization results of the nonlinear quantization circuit and the noise shaping and modulation circuit to generate a complete quantization result; The inverse nonlinear transformation unit restores the quantization result output by the arithmetic logic unit to the linear proportional binary code corresponding to the original signal value according to the lookup table.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a piecewise linear quantization hybrid structure analog-to-digital converter with noise shaping function. It achieves nonlinear coarse quantization by adjusting the successive approximation structure, performs fine quantization using noise shaping technology, and realizes overall piecewise linearity by providing a reference voltage for linear fine quantization through nonlinear coarse quantization.

[0013] Compared with other technologies, the technology described in this invention combines a successive approximation structure and a Sigma-Delta structure, which can realize a high-precision nonlinear analog-to-digital converter and extend the dynamic range in analog-to-digital converters of the same precision. Attached Figure Description

[0014] Figure 1 This is a block diagram of the piecewise linear quantization hybrid analog-to-digital converter with noise shaping function described in this invention;

[0015] Figure 2 This is a block diagram of a piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in a specific embodiment of the present invention.

[0016] Figure 3 This is a schematic diagram of the structure of the piecewise linear quantization hybrid analog-to-digital converter with noise shaping function described in Embodiment 1 of the present invention.

[0017] Figure 4 This is a schematic diagram of the structure of the piecewise linear quantization hybrid analog-to-digital converter with noise shaping function described in Embodiment 2 of the present invention.

[0018] Figure 5 This is a comparison chart of the signal-to-noise ratio characteristic curves of Embodiment 1 and Comparative Example 1 of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this does not limit the scope of the invention in any way.

[0020] Please see Figure 1 and Figure 2 ,in Figure 1 This is a block diagram of the piecewise linear quantization hybrid analog-to-digital converter with noise shaping function described in this invention. Figure 2 This is a block diagram of a piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in a specific embodiment of the present invention.

[0021] The core of this invention is to propose a piecewise linear quantization hybrid analog-to-digital converter with noise shaping function. Please refer to [link to relevant documentation]. Figure 1The piecewise linear quantization hybrid analog-to-digital converter with noise shaping function includes an input control circuit 100, a nonlinear quantization circuit 200, a noise shaping and modulation circuit 300, an output control circuit 400, and a digital decimation filter circuit 500. The input control circuit 100 is connected to the nonlinear quantization circuit 200 and the noise shaping and modulation circuit 300. The nonlinear quantization circuit 200 and the noise shaping and modulation circuit 300 are connected. The output control circuit 400 is connected to the nonlinear quantization circuit 200 and the noise shaping and modulation circuit 300. The digital decimation filter circuit 500 is connected to the output control circuit 400.

[0022] The input control circuit 100 is used to receive the original input signal, perform amplitude conversion, and control the nonlinear quantization circuit 200 and the noise shaping and modulation circuit 300 to receive the input signal. The nonlinear quantization circuit 200 receives the input signal and determines the nonlinear segment in which it is located, provides a reference signal for the noise shaping and modulation circuit 300, and outputs the segment code of the segment in which the signal is located. The noise shaping and modulation circuit 300 oversamples the input signal and performs noise shaping and uniform fine quantization on the signal residual after nonlinear quantization based on the reference signal from the nonlinear quantization circuit 200, modulating the noise in the signal band to outside the signal band and outputting the segment code. The output control circuit 400 receives the output results of the nonlinear quantization circuit 200 and the noise shaping and modulation circuit 300, buffers the digital code in the quantization process, integrates the segment code output by the nonlinear quantization circuit 200 and the intra-segment code output by the noise shaping and modulation circuit 300, and converts the complete output result into digital code with corresponding linear intervals. The digital extraction and filtering circuit 500 receives the digital code output by the output control circuit, filters out high-frequency noise generated by noise shaping outside the signal frequency band, and converts it to generate a high-precision digital code.

[0023] In this embodiment, the input control circuit 100 receives the input signal, performs amplitude conversion, and generates a clock signal to control the nonlinear quantization circuit 200 and the noise shaping and modulation circuit 300 to sample the input signal; the nonlinear quantization circuit 200 consists of a nonlinear digital-to-analog converter 201, a comparator unit 202, a successive approximation register 203, and a decoder 204; the noise shaping and modulation circuit 300 consists of a filter 301, a quantizer 302, a logic circuit 303, and a digital-to-analog converter 304; the output control circuit 400 includes a segment code buffer unit 401, an intra-segment code buffer unit 402, an arithmetic logic unit 403, and an inverse nonlinear transformation unit 404.

[0024] The nonlinear quantization circuit 200 performs nonlinear successive approximation quantization on the input signal under the control of the successive approximation register 203. The nonlinear transfer characteristics of the nonlinear quantization circuit 200 are determined by the nonlinear weighted capacitor array in the nonlinear digital-to-analog converter 201. The nonlinear digital-to-analog converter 201 includes two digital-to-analog conversion units, which are used to generate the start-point reference signal and the end-point reference signal of the nonlinear segment interval, respectively. In the first conversion cycle, the nonlinear digital-to-analog converter 201 generates an estimated start-point reference signal under the control of the successive approximation register 203. The comparator unit 202 determines the range of the input signal by comparing the magnitude of the start-point reference signal generated by the nonlinear digital-to-analog converter 201 with the magnitude of the input signal, and feeds back the comparison result to the successive approximation register. The binary code output by the successive approximation register 203 is converted into thermometer code by the decoder 204, which then controls the nonlinear digital-to-analog converter 201 to further approximate the input signal. When the segment code determined by the successive approximation register 203 has M bits, the nonlinear quantization circuit 200 needs M+1 cycles to determine the nonlinear segment interval where the input signal is located. The successive approximation register 203 outputs the determined segment code to the segment code buffer unit 401. The nonlinear digital-to-analog converter 201 generates the start reference signal and the end reference signal of the nonlinear segment interval where the signal is located, and connects them to the digital-to-analog converter 304. The digital-to-analog converter 304 samples and holds the start reference signal and the end reference signal under clock control, thereby performing fine quantization.

[0025] Furthermore, the noise shaping and modulation circuit 300 oversamples the input signal under clock control and obtains the signal residual based on the reference signal generated by the nonlinear digital-to-analog converter 201. The quantization bit depth of the noise shaping and modulation circuit 300 is fixed, and the quantization interval is uniformly distributed within the nonlinear segment interval where the signal is located. The size of the quantization interval is determined by the start-point reference signal and the end-point reference signal generated by the nonlinear digital-to-analog converter 201. After the signal residual is input to the filter 301, it is converted into an integral signal. The integral signal is input to the quantizer 302 for one or more-bit quantization. The quantizer 302 outputs the quantized digital code to the segment code buffer unit 402 and the logic circuit. In circuit 303, logic circuit 303 controls digital-to-analog converter 304 to output a feedback signal based on the quantization result of quantizer 302, thereby performing further quantization; the arithmetic logic unit 403 integrates the quantization results of nonlinear quantization circuit 200 and noise shaping modulation circuit 300 to generate a complete quantization result, and inputs it to inverse nonlinear transformation unit 404. Inverse nonlinear transformation unit 404 restores the complete quantization result to the linear proportional binary digital code corresponding to the original signal value according to the lookup table, and inputs it to digital decimation filter circuit 500, thereby filtering out high-frequency noise generated by noise shaping outside the signal frequency band and converting it into a high-precision digital code.

[0026] In some specific implementations, the noise shaping and modulation circuit 300 uses a noise shaping successive approximation structure; the quantizer 302 is a one-bit quantizer, i.e., a comparator; the logic circuit 303 is implemented as a successive approximation register, and the quantizer and logic circuit can be shared with the nonlinear quantization circuit. In this case, the first M bits of the output of the successive approximation register are segment codes, which are used to control the nonlinear quantization circuit, and the last N bits are intra-segment codes, which are used to control the noise shaping and modulation circuit. The circuit is divided into three quantization stages: In the first stage, nonlinear successive approximation is achieved through the nonlinear quantization circuit 200. The second stage, linear successive approximation, is achieved through the noise shaping and modulation circuit 300. The third stage, noise shaping, is achieved through the noise shaping modulation circuit 300.

[0027] Example 1

[0028] Please see Figure 3 This embodiment provides a piecewise linear quantization hybrid analog-to-digital converter with noise shaping function that implements A-law 13-segmented line transfer characteristics. The noise shaping and modulation circuit 300 uses a Sigma-Delta structure and consists of a filter, a quantizer, logic circuits (scaling logic), and a digital-to-analog converter (DAC). The nonlinear quantization circuit 200 consists of a nonlinear digital-to-analog converter (NLDAC), a comparator, a successive approximation register, and a decoder. The nonlinear quantization circuit 200 and the noise shaping and modulation circuit 300 operate in parallel, with a signal bandwidth of [missing information]. The oversampling rate of the circuit is OSR, and the sampling frequencies of the nonlinear quantization circuit 200 and the noise shaping and modulation circuit 300 are both... The nonlinear quantization circuit 200 divides the input signal into different nonlinear segment intervals and generates a reference signal for the starting point of the nonlinear segment interval in which the signal is located. and endpoint reference signal The noise shaping and modulation circuit 300 linearly quantizes the signal within the segment based on the nonlinear reference voltage provided by the nonlinear quantization circuit 200. To prevent the input signal from exceeding the range of the nonlinear quantization circuit 200, a scaling factor M is set. The scaling logic controls the DAC output feedback signal based on the LSB output result of the quantizer.

[0029] Therefore, the signal at the filter input is the difference between the input signal and the feedback signal, and the actual modulation object is the quantization residual of the nonlinear quantization circuit.

[0030] Example 2

[0031] Please see Figure 4 This embodiment provides a piecewise linear quantization hybrid analog-to-digital converter with noise shaping function, where the noise shaping and modulation circuit 300 uses a noise shaping successive approximation structure. The noise shaping and modulation circuit 300 and the nonlinear quantization circuit 200 share a quantizer (comparator) and logic circuit (successive approximation register). In the nonlinear quantization circuit 200, the nonlinear digital-to-analog converter 201 corresponds to the NLDAC module in the figure, the comparator unit 202 corresponds to the comparator module in the figure, the successive approximation register 203 corresponds to the successive approximation register module in the figure, and the decoder 204 corresponds to the decoder module in the figure. The filter in the noise shaping and modulation circuit 300... 301 corresponds to the filter module in the diagram, quantizer 302 corresponds to the comparator module, logic circuit 303 corresponds to the successive approximation register module, and digital-to-analog converter 304 corresponds to the DAC module. At this time, the first M bits of the successive approximation register output are segment codes, used to control the nonlinear quantization circuit, and the last N bits are intra-segment codes, used to control the noise shaping and modulation circuit. Simultaneously, since the successive approximation register can automatically combine the outputs of the noise shaping and modulation circuit 300 and the nonlinear quantization circuit 200, the function of the output control circuit 400 is replaced by the successive approximation register. At this time, the circuit is divided into three quantization stages: In the first stage, nonlinear successive approximation occurs, at which point the switch... Close, switch When disconnected, the noise shaping and modulation circuit does not work. The first M bits of the segment code controlled by the successive approximation register are converted into thermometer code by the decoder and the NLDAC is controlled to complete the output. The comparator compares the output of the NLDAC with the input signal and inputs the result into the successive approximation register. After a total of M+1 cycles, the nonlinear successive approximation is completed. In the second stage, linear successive approximation is performed, at which point the switch... , When disconnected, the nonlinear quantization circuit 200 does not work. The output of the NLDAC is maintained and a reference signal is provided for the DAC. The successive approximation register controls the last N bits of the output segment code and controls the DAC to complete the output. The comparator compares the output of the DAC with the input signal and inputs the result into the successive approximation register. After N cycles, the nonlinear successive approximation is completed. The third stage is noise shaping, at which point the switch... Close, switch When disconnected, the nonlinear quantization circuit 200 does not operate, the output of the NLDAC is maintained, and a reference signal is provided for the DAC; the successive approximation register controls the DAC to generate a residual signal, and through... The residual signal is input to the filter, processed by the filter, added to the input signal, and then fed back to the comparator to determine the last bit of digital output, thereby achieving noise shaping.

[0032] Comparative Example 1

[0033] This comparative example replaces the nonlinear quantization circuit 200 in the piecewise linear quantization hybrid analog-to-digital converter with noise shaping function that realizes the A-law 13-fold line transfer characteristic described in Example 1 with a linear successive final analog-to-digital converter with the same number of bits, and evaluates the performance of the two analog-to-digital converters.

[0034] To further illustrate the effect of the piecewise linear quantization hybrid analog-to-digital converter with noise shaping function provided by the present invention, Figure 5 This is a comparison chart of the signal-to-noise ratio characteristic curves of Embodiment 1 and Comparative Example 1 of the present invention; as shown Figure 5 As shown in the figure, the horizontal axis represents the normalized amplitude of the input signal in dB, and the vertical axis represents the signal-to-noise ratio (SNR) at the corresponding amplitude in dB. The red line in the figure corresponds to a piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in Example 1, and the black line in the figure corresponds to the linear quantization analog-to-digital converter with the same number of bits used for comparison in Comparative Example 1. It can be seen that, under the premise of the same number of quantization bits, the piecewise linear quantization hybrid analog-to-digital converter with noise shaping function provided by this invention, compared with the linear quantization analog-to-digital converter, expands the dynamic range with an SNR greater than 100 dB from 25 dB to 45 dB, and the SNR improvement value for small signals is 20 dB.

[0035] This invention can be applied to sensor fields such as audio sensors, image sensors, humidity and temperature sensors, where the signals of interest are not uniformly distributed and high precision and high dynamic range are required.

[0036] The above-described embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the processes of the above embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A piecewise linear quantization hybrid analog-to-digital converter with noise shaping function, characterized in that: It includes an input control circuit, a nonlinear quantization circuit, a noise shaping and modulation circuit, an output control circuit, and a digital decimation and filtering circuit. The input control circuit is connected to the nonlinear quantization circuit and the noise shaping and modulation circuit. The nonlinear quantization circuit and the noise shaping and modulation circuit are connected. The output control circuit is connected to the nonlinear quantization circuit and the noise shaping and modulation circuit. The digital decimation and filtering circuit is connected to the output control circuit. The input control circuit is used to receive the original input signal, perform amplitude conversion, and control the nonlinear quantization circuit and noise shaping modulation circuit to receive the input signal. The nonlinear quantization circuit receives the input signal and determines the nonlinear segment in which it is located, thereby providing a reference signal for the noise shaping and modulation circuit. The noise shaping and modulation circuit oversamples the input signal and performs noise shaping and further quantization on the signal residual after nonlinear quantization based on the reference signal from the nonlinear quantization circuit, modulating the noise in the signal band to outside the signal band and outputting the segment code.

2. The piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in claim 1, characterized in that: The output control circuit receives the output results of the nonlinear quantization circuit and the noise shaping and modulation circuit, stores the digital code in the quantization process, and performs buffering, processing and output. The digital decimation filter circuit receives the high-speed digital code output by the output control circuit, filters out high-frequency noise outside the signal frequency band generated by noise shaping, and converts it into a high-precision digital code.

3. The piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in claim 2, characterized in that: The nonlinear quantization circuit uses a successive approximation structure for coarse quantization and includes a nonlinear digital-to-analog converter, a comparator unit, a successive approximation register, and a decoder. The nonlinear digital-to-analog converter uses a nonlinear weighted capacitor array to realize the nonlinear transfer characteristics of the circuit, and controls the nonlinear capacitor array to achieve charge scaling by inputting thermometer codes to generate a reference voltage; The comparator unit is used to connect the system input signal sampled by the input control circuit and the signal generated by the digital-to-analog converter in the nonlinear quantization circuit, and to compare the two. The successive approximation register uses logic circuits to implement the successive approximation algorithm, receives the output of the comparator, and controls the quantization circuit to complete the successive approximation quantization. The decoder is used to connect the successive approximation register and the nonlinear quantization circuit, and converts the output binary code of the successive approximation register, which controls the nonlinear quantization circuit, into thermometer code.

4. The piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in claim 3, characterized in that: The nonlinear quantization circuit includes a nonlinear digital-to-analog converter comprising two digital-to-analog conversion units, each used to generate a reference signal for the starting point of the nonlinear segment interval in which the signal resides. and endpoint reference signal .

5. The piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in claim 4, characterized in that: The noise shaping and modulation circuit uses a Sigma-Delta structure to achieve noise shaping. The Sigma-Delta structure includes first-order, multi-order, and multi-stage cascaded structures, and consists of filters, quantizers, logic circuits, and digital-to-analog converters. The filter is used to convert the quantization residual of the nonlinear quantization circuit into an integral signal, and input the integral signal to the quantizer for quantization. The quantizer performs one or more bit quantization on the integral signal generated by the filter and outputs a high-speed digital code as a partial quantization result. The logic circuit is connected to the output control circuit and the digital-to-analog converter, and controls the digital-to-analog converter to output a corresponding feedback signal based on the quantization result input to the output control circuit.

6. The piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in claim 5, characterized in that: The digital-to-analog converter is connected to the nonlinear digital-to-analog converter, receives the reference signal generated by the nonlinear digital-to-analog converter, and generates a feedback signal based on the reference signal under the control of the logic circuit.

7. The piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in claim 6, characterized in that: The noise shaping and modulation circuit and the nonlinear quantization circuit operate in parallel.

8. The piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in claim 4, characterized in that: The noise shaping and modulation circuit uses a modulator with a noise shaping successive approximation structure, which includes a comparator unit, a successive approximation register, a filter, and a digital-to-analog converter; The comparator unit and the successive approximation register are shared with the nonlinear quantization circuit. The first M bits of the output of the successive approximation register are segment codes, which are used to control the nonlinear quantization circuit, and the last N bits are intra-segment codes, which are used to control the noise shaping and modulation circuit. The digital-to-analog converter is connected to the nonlinear digital-to-analog converter, receives the reference signal generated by the nonlinear digital-to-analog converter, and generates a feedback signal based on the reference signal under the control of the successive approximation register.

9. The piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in claim 8, characterized in that: The circuit consists of three quantization stages: In the first stage, nonlinear successive approximation is achieved through the nonlinear quantization circuit. The second stage, linear successive approximation, is achieved through the noise shaping modulation circuit of the noise shaping successive approximation structure. The third stage, noise shaping, is achieved through the noise shaping modulation circuit of the noise shaping successive approximation structure.

10. The piecewise linear quantization hybrid analog-to-digital converter with noise shaping function as described in claim 2, characterized in that: The output control circuit includes a segment code buffer unit, an intra-segment code buffer unit, an arithmetic logic unit, and an inverse nonlinear transformation unit. The segment code buffer unit is used to buffer and output the quantization result of the nonlinear quantization circuit during the quantization process; The segment code buffer unit is used to buffer and output the quantization result of the noise shaping modulation circuit during the quantization process; The arithmetic logic unit is used to integrate the quantization results of the nonlinear quantization circuit and the noise shaping and modulation circuit to generate a complete quantization result; The inverse nonlinear transformation unit restores the quantization result output by the arithmetic logic unit to the linear proportional binary code corresponding to the original signal value according to the lookup table.

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