Annular amplifier

Abstract

The invention relates to the technical field of analog circuit design, and discloses a ring amplifier, which is characterized by comprising a multi-stage amplification circuit and a level shift circuit, the input end of the multi-stage amplification circuit is connected with the signal input end of the ring amplifier, and the output end of the multi-stage amplification circuit is connected with the first end of the level shift circuit; the second end of the level shift circuit is connected with the signal output end of the ring amplifier; the level shift circuit comprises a first switch, a second switch, a third switch and a third capacitor, and the first end of the level shift circuit is connected to the second end of the level shift circuit through the first switch; the second end of the level shift circuit is connected with the first end of the third capacitor; the first end of the level shift circuit is connected with the second end of the third capacitor through the second switch. By arranging the multi-pole annular amplifying circuit and introducing the level shifting circuit, the index requirements of high gain, high bandwidth and low power consumption can be met under low voltage.

Description

Technical Field

[0001] The present invention relates to the technical field of analog circuit design, and particularly relates to a ring amplifier. Background Art

[0002] In analog circuit design, especially in application scenarios that require high performance and low power consumption (such as pipelined successive approximation analog-to-digital converters, Pipelined-SAR-ADC), traditional operational amplifiers are key components for signal amplification. Traditional operational amplifier designs usually rely on multi-stage amplification structures, cascading between stages to increase the overall gain, and stabilizing the output through a feedback mechanism, performing well when the power supply voltage is high and the power consumption requirements are not strict.

[0003] However, with the continuous progress of semiconductor processes, the power supply voltage has gradually decreased, which poses a severe challenge to the design of traditional operational amplifiers. In advanced processes, the reduction of the power supply voltage leads to a decrease in the power supply voltage margin of the operational amplifier, making it difficult for the performance of the operational amplifier, such as gain, bandwidth, and power consumption, to meet the design requirements. Especially in low-power applications, how to reduce power consumption while maintaining high performance has become an urgent problem to be solved. Summary of the Invention

[0004] In view of this, the present invention provides a ring amplifier to solve the problem that traditional operational amplifiers are difficult to meet the design requirements of high performance and low power consumption.

[0005] In a first aspect, the present invention provides a ring amplifier, which includes: a multi-stage amplification circuit and a level shift circuit;

[0006] The input end of the multi-stage amplification circuit is connected to the signal input end of the ring amplifier, and the output end of the multi-stage amplification circuit is connected to the first end of the level shift circuit; the second end of the level shift circuit is connected to the signal output end of the ring amplifier;

[0007] The level shift circuit includes a first switch, a second switch, a third switch, and a third capacitor. The first end of the level shift circuit is connected to the second end of the level shift circuit through the first switch; the second end of the level shift circuit is connected to the first end of the third capacitor; the first end of the level shift circuit is connected to the second end of the third capacitor through the second switch.

[0008] The ring amplifier provided by the embodiment of the present invention allows the ring amplifier to operate at a lower power supply voltage by introducing a level shift circuit, enabling high performance to be maintained while reducing the overall power consumption.

[0009] In an optional implementation manner, the second end of the third capacitor is also connected to a common-mode voltage terminal through a third switch, and the common-mode voltage terminal is used to reset the circuit of the ring amplifier.

[0010] The ring amplifier provided by the embodiment of the present invention can realize the reset function of the circuit by connecting the second end of the third capacitor to the common-mode voltage terminal through the third switch, so as to eliminate the residual signals in the previous amplification process and ensure the stable operation of the ring amplifier in the initial state or under specific conditions.

[0011] In an alternative embodiment, the multi-stage amplification circuit includes a cascaded first-stage amplification circuit, a second-stage amplification circuit, and a third-stage amplification circuit; the first-stage amplification circuit, the second-stage amplification circuit, and the third-stage amplification circuit all include a plurality of switching tubes.

[0012] The ring amplifier provided by the embodiment of the present invention can significantly improve the overall gain of the ring amplifier by cascading multi-stage amplification circuits. At the same time, through the multi-stage amplification structure, the cascading between stages can optimize the frequency response and reduce the attenuation of high-frequency signals, which helps to improve the bandwidth performance.

[0013] In an alternative embodiment, the first-stage amplification circuit includes a first switching tube and a second switching tube, and the signal input terminal of the ring amplifier is connected to the input terminal of the first-stage amplification circuit through a first capacitor; the input terminal of the first-stage amplification circuit is respectively connected to the control terminals of the first switching tube and the second switching tube;

[0014] In the first-stage amplification circuit, the power supply voltage terminal is connected to the output terminal of the first-stage amplification circuit through the first switching tube; the output terminal of the first-stage amplification circuit is grounded through the second switching tube.

[0015] The ring amplifier provided by the embodiment of the present invention can filter and decouple the input signal through the connection between the first capacitor and the signal input terminal, reduce noise interference, and improve the purity and stability of the signal. As controllable elements, the first switching tube and the second switching tube can change performance parameters such as the gain and bandwidth of the circuit by adjusting their control signals, so as to meet the requirements of different application scenarios.

[0016] In an alternative embodiment, the second-stage amplification circuit includes a third switching tube, a fourth switching tube, and a first resistor;

[0017] The output terminal of the first-stage amplification circuit is connected to the input terminal of the second-stage amplification circuit; the input terminal of the second-stage amplification circuit is respectively connected to the control terminals of the first switching tube and the second switching tube;

[0018] In the second-stage amplification circuit, the power supply voltage terminal is connected to the first end of the first resistor through the third switching tube; the second end of the first resistor is grounded through the fourth switching tube.

[0019] The ring amplifier provided by the embodiment of the present invention can provide a voltage drop by setting the first resistor, so that the third-stage amplifier circuit is in the sub-threshold region and does not cut off. At the same time, setting the first resistor helps to stabilize the output of the second-stage amplifier circuit to improve its PVT stability.

[0020] In an alternative embodiment, the third-stage amplifier circuit includes a fifth switching transistor and a sixth switching transistor; the first end of the first resistor is connected to the control end of the fifth switching transistor; the second end of the first resistor is connected to the control end of the sixth switching transistor;

[0021] In the third-stage amplifier circuit, the power supply voltage terminal is connected to the output terminal of the third-stage amplifier circuit through the fifth switching transistor; the output terminal of the third-stage amplifier circuit is grounded through the sixth switching transistor.

[0022] The ring amplifier provided by the embodiment of the present invention can further adjust the gain of the third-stage amplifier circuit by adjusting the conduction states of the fifth switching transistor and the sixth switching transistor. Combining the designs of the first two-stage amplifier circuits enables the ring amplifier of the present invention to provide a wide range of gain adjustment according to different application scenarios and requirements, thereby optimizing the signal amplification effect.

[0023] In an alternative embodiment, the ring amplifier further includes a second capacitor;

[0024] One end of the second capacitor is connected to the first capacitor, and the other end of the second capacitor is connected to the signal output terminal of the ring amplifier.

[0025] The ring amplifier provided by the embodiment of the present invention can form an additional feedback path by setting the second capacitor. By adjusting the capacitance value of the second capacitor, the frequency response of the circuit can be adjusted to reduce high-frequency oscillation and noise, thereby improving the stability of the amplifier. At the same time, the second capacitor can act as an energy storage element to help smooth the fluctuations of the power supply voltage and reduce the power consumption caused by unstable power supply voltage.

[0026] In a second aspect, the present invention provides a pipelined successive approximation analog-to-digital converter including the ring amplifier of the first aspect.

[0027] The pipelined successive approximation analog-to-digital converter provided by the embodiment of the present invention can achieve high gain, high bandwidth, and low power consumption under low voltage conditions by adopting the ring amplifier architecture of the first aspect, and is suitable for integrated circuit design in modern advanced processes.

[0028] In a third aspect, the present invention provides a voltage amplification method applied to the ring amplifier of the first aspect. The method includes:

[0029] Closing the first switch and the third switch and opening the second switch so that the third-stage amplifier circuit conducts to perform the first amplification on the input signal;

[0030] Close the second switch, and open the first switch and the third switch, so that the third-stage amplifier circuit is coupled through the third capacitor to perform a second amplification on the input signal.

[0031] The voltage amplification method provided by the embodiments of the present invention can meet the index requirements of high gain, high bandwidth, and low power consumption at low voltage by setting up a multi-stage ring amplifier circuit and introducing a level shift circuit.

[0032] In an alternative embodiment, the method further includes: connecting the signal input terminal of the ring amplifier, the signal output terminal of the ring amplifier, and the third-stage amplifier circuit to the common-mode voltage, so that the circuit of the ring amplifier is reset.

[0033] The voltage amplification method provided by the embodiments of the present invention can ensure that all node voltages return to a known fixed level, that is, the common-mode voltage, before the next amplification, so as to eliminate the signals that may remain in the previous amplification process and avoid interference or errors in the next amplification. Description of the Drawings

[0034] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 is a schematic diagram of the architecture of a ring amplifier according to an embodiment of the present invention;

[0036] Figure 2 is the circuit diagram of a ring amplifier according to an embodiment of the present invention. Detailed Embodiments

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0038] In analog circuit design, especially in application scenarios that require high performance and low power consumption (such as pipelined successive approximation analog-to-digital converter, Pipelined-SAR-ADC), traditional operational amplifiers are key components for signal amplification. Traditional op amp designs usually rely on multi-stage amplification structures, which improve the overall gain by cascading between each stage and stabilize the output through a feedback mechanism. They perform well when the power supply voltage is high and the power consumption requirements are not strict.

[0039] However, in advanced manufacturing processes, traditional op amps have been unable to meet the design requirements of high performance and low power consumption. Therefore, the inventors have proposed a ring amplifier architecture using level shifting technology that can achieve high gain, high bandwidth and low power consumption at low voltage.

[0040] According to an embodiment of the present invention, a ring amplifier embodiment is provided, the ring amplifier comprising: a multi-stage amplification circuit and a level shift circuit;

[0041] The input end of the multi-stage amplifier circuit is connected to the signal input end of the ring amplifier, the output end of the multi-stage amplifier circuit is connected to the first end of the level shift circuit; the second end of the level shift circuit is connected to the signal output end of the ring amplifier;

[0042] The level shift circuit includes a first switch, a second switch, a third switch and a third capacitor. The first end of the level shift circuit is connected to the second end of the level shift circuit through the first switch; the second end of the level shift circuit is connected to the first end of the third capacitor; the first end of the level shift circuit is connected to the second end of the third capacitor through the second switch.

[0043] like Figure 1 As shown, the ring amplifier shown in this embodiment includes a multi-stage amplifier circuit and a level shift circuit, such as Figure 2 As shown, the ring amplifier shown in this embodiment controls the first switch S1, the second switch S2 and the third switch S3 through the timing logic to realize the multi-stage amplification process and level shifting, ensuring that the switch state is switched at the correct time point to achieve the desired amplification effect. Specifically:

[0044] The input end of the multi-stage amplifier circuit is connected to the signal input end (VIN) of the ring amplifier. The level shift circuit is used to raise and shift the output level after the amplification process is completed, so as to achieve a higher gain. The level shift circuit includes a first switch S1, a second switch S2, a third switch S3 and a third capacitor C3.

[0045] The first end of the level shifting circuit, which is the output end of the multi-stage amplifier circuit, is connected to the second end of the level shifting circuit, i.e., the signal output end VOUT of the ring amplifier, through the first switch S1. The second end of the level shifting circuit is connected to the first end of the third capacitor C3. The first end of the level shifting circuit is connected to the second end of the third capacitor C3 through the second switch S2. The third switch S3 is used to control the direct connection between the multi-stage amplifier circuit and VOUT or the coupling connection through C3 during the amplification process.

[0046] In some alternative embodiments, the second end of the third capacitor is also connected to the common mode voltage terminal through the third switch, and the common mode voltage terminal is used to reset the circuit of the ring amplifier.

[0047] When the amplifier completes an amplification cycle, by closing the third switch, the charge on the third capacitor C3 can be quickly released to the common mode voltage VCM through this path. The VCM terminal serves as the charge receiving end at this time, helping C3 quickly release the charge until the voltage on C3 drops close to VCM. In other words, during the normal amplification process, C3 acts as a level shifting capacitor, and through the charging and discharging process, the level of the output signal of the multi-stage amplifier circuit is lifted; during the reset stage, C3 serves as the path for charge release, ensuring that the ring amplifier can return to the initial state and be ready for the next amplification.

[0048] In some alternative embodiments, the multi-stage amplifier circuit includes a cascaded first-stage amplifier circuit, a second-stage amplifier circuit, and a third-stage amplifier circuit; the first-stage amplifier circuit, the second-stage amplifier circuit, and the third-stage amplifier circuit all include multiple switching transistors.

[0049] As Figure 2 shown, the first-stage amplifier circuit, as the input stage of the amplifier, is followed by the second-stage amplifier circuit, which is mainly responsible for further amplifying the signal transmitted from the first stage. The third-stage amplifier circuit serves as the output stage of the amplifier, and its design aims to provide high DC gain and ensure the stability of the loop.

[0050] In some alternative embodiments, the first-stage amplifier circuit includes a first switching transistor and a second switching transistor. The signal input end of the ring amplifier is connected to the input end of the first-stage amplifier circuit through the first capacitor; the input end of the first-stage amplifier circuit is respectively connected to the control ends of the first switching transistor and the second switching transistor;

[0051] In the first-stage amplifier circuit, the power supply voltage terminal is connected to the output end of the first-stage amplifier circuit through the first switching transistor; the output end of the first-stage amplifier circuit is grounded through the second switching transistor.

[0052] The first-stage amplifier circuit, as the input stage of the amplifier, is mainly composed of a pair of switching transistors, as Figure 2As shown, the pair of switching transistors can be a pair of differential input transistors M1 and M2. This pair of differential input transistors is responsible for receiving the input signal of the signal input terminal VIN and converting it into a current signal for amplification. The input capacitor C1 is used to store and transmit the input signal.

[0053] Preferably, in order to optimize the bandwidth of the amplifier, the transistors in the first stage usually adopt a design with a large width-to-length ratio to improve the bandwidth of the amplifier.

[0054] In some alternative embodiments, the second-stage amplification circuit includes a third switching transistor, a fourth switching transistor, and a first resistor;

[0055] The output terminal of the first-stage amplification circuit is connected to the input terminal of the second-stage amplification circuit; the input terminal of the second-stage amplification circuit is respectively connected to the control terminals of the first switching transistor and the second switching transistor;

[0056] In the second-stage amplification circuit, the power supply voltage terminal is connected to the first end of the first resistor through the third switching transistor; the second end of the first resistor is grounded through the fourth switching transistor.

[0057] The drain of the third switching transistor M3 is connected to the power supply voltage terminal VDD, and the source is connected to the first end of the first resistor R1. M3 controls the path of the power supply voltage to the first resistor R1. When M3 is turned on, a voltage drop is generated across R1 by VDD, and this voltage drop directly affects the working state of the subsequent third-stage amplification circuit.

[0058] Optionally, the third switching transistor M3 and the fourth switching transistor M4 are MOS transistors. Specifically: when the ring amplifier according to the embodiment of the present invention starts to work, the first two stages are similar to a bidirectional comparator, selectively turning on the switching transistors of the third-stage amplification circuit, thereby performing a continuous charge and discharge process on the load. However, due to the voltage drop provided by R1, the switching transistors of the third-stage amplification circuit gradually change from fully turned on to operating in the subthreshold region, causing the main pole to move closer to the origin, increasing the gain, decreasing the bandwidth, increasing the phase margin, and making the output tend to be stable from oscillation, and finally completing the amplification of the signal.

[0059] Preferably, the transistors selected for the first two stages of the amplification circuit usually have the minimum gate length, and among them, the width-to-length ratio of the switching transistors in the first-stage amplification circuit is relatively large.

[0060] In some alternative embodiments, the third-stage amplification circuit includes a fifth switching transistor and a sixth switching transistor; the first end of the first resistor is connected to the control terminal of the fifth switching transistor; the second end of the first resistor is connected to the control terminal of the sixth switching transistor;

[0061] In the third-stage amplification circuit, the power supply voltage terminal is connected to the output terminal of the third-stage amplification circuit through the fifth switching transistor; the output terminal of the third-stage amplification circuit is grounded through the sixth switching transistor.

[0062] The control terminal of the fifth switching transistor M5 is connected to one end of the first resistor R1; the control terminal of the sixth switching transistor M6 is connected to the other end of the first resistor R1.

[0063] Both the fifth switching transistor M5 and the sixth switching transistor M6 can be MOS transistors. Figure 2 Taking this as an example, the source of the fifth switching transistor M5 is connected to the power supply voltage terminal VDD; the source of the sixth switching transistor M6 is grounded. The power supply voltage terminal VDD is connected to the output terminal of the third-stage amplifier circuit through the fifth switching transistor M5. The function of M6 is to ground the output terminal of the third-stage amplifier circuit under the drive of the control signal, thereby forming a discharge path.

[0064] In some alternative embodiments, the ring amplifier further includes a second capacitor;

[0065] One end of the second capacitor is connected to the first capacitor, and the other end of the second capacitor is connected to the signal output terminal of the ring amplifier.

[0066] The introduction of the second capacitor C2 helps to form an additional low-frequency feedback path between the input and the output, which helps to reduce the instability of the output signal caused by the input signal fluctuation. Specifically, by providing an additional capacitive feedback, the second capacitor can smooth the high-frequency noise in the input signal, thereby improving key performance indicators such as the signal-to-noise ratio and total harmonic distortion of the amplifier.

[0067] The addition of the second capacitor may also help to expand the dynamic range of the amplifier. By providing an additional capacitive energy storage element, it can increase the difference between the maximum amplitude of the output signal and the minimum detectable signal level without increasing the power consumption of the amplifier.

[0068] According to an embodiment of the present invention, there is provided a pipelined successive approximation analog-to-digital converter including the ring amplifier of the first aspect.

[0069] This embodiment proposes a high-performance and low-power pipelined successive approximation analog-to-digital converter (Pipelined-SAR-ADC), the core of which is to adopt the ring amplifier architecture in the above embodiment. It can achieve high gain, high bandwidth and low power consumption under low voltage conditions, and is very suitable for integrated circuit design in modern advanced processes.

[0070] According to an embodiment of the present invention, there is provided a voltage amplification method applied to the ring amplifier of the first aspect. The method includes:

[0071] Closing the first switch and the third switch, and disconnecting the second switch, so that after the third-stage amplifier circuit is turned on, the input signal is amplified for the first time;

[0072] Close the second switch and open the first switch and the third switch so that the third-stage amplifier circuit is capacitively coupled through the third capacitor to perform a second amplification on the input signal.

[0073] The switches are controlled by a timing logic circuit, and the amplification process is carried out twice. First, close the first switch S1, and the input signal is allowed to enter the first and second stages of the amplifier for preliminary amplification. At the same time, the closing of the third switch S3 directly connects the third-stage amplifier circuit to the VOUT output terminal. Please refer to Figure 2 , specifically, in this process, the input signal is first preliminarily amplified by the input pair transistors M1 and M2 in the first-stage amplifier circuit; then, the signal passes through the second-stage amplifier circuit composed of M3 and M4, where the first resistor R1 provides PVT stability; finally, the signal is further amplified by the fifth switch transistor M5 and the sixth switch transistor M6 in the third-stage amplifier circuit and directly output to VOUT. The signal amplified by the first two stages will be directly further amplified by the third stage and output to VOUT. During this period, S2 remains open to ensure that the third-stage amplifier circuit is not capacitively coupled to VOUT through the C3 capacitor.

[0074] After the first amplification is completed, S1 is opened to cut off the direct connection between the input signal and the first two stages of the amplifier. At the same time, S3 is also opened to disconnect the direct connection between the third-stage amplifier circuit and VOUT. At this time, S2 is closed, allowing the third-stage amplifier circuit to be capacitively coupled to VOUT through the C3 capacitor, and C3 serves as a level-shifting capacitor. After S2 is closed, the input signal has been preliminarily amplified by C1 and the first two stages of the amplifier and is allowed to enter the amplification process again. At this time, the third-stage amplifier circuit is not directly connected to VOUT but is capacitively coupled through the C3 capacitor. Due to the coupling effect of C3, the output of the third-stage amplifier circuit will be lifted or shifted by a specific level value. This level value depends on the capacitance value of C3, the initial level of VOUT, and the gain of the amplifier. After the second amplification, the level on VOUT will change accordingly again according to the magnitude of the input signal and the gain of the amplifier.

[0075] Since the amplification process is carried out twice, the charge on the input capacitor C1 is transferred twice. This means that the equivalent gain of the circuit approximately changes from A times to A^2 times.

[0076] In some alternative embodiments, the method further includes: connecting the signal input terminal of the ring amplifier, the signal output terminal of the ring amplifier, and the third-stage amplifier circuit to a common-mode voltage to reset the circuit of the ring amplifier.

[0077] After the amplification process ends, the VIN input, the VOUT output, and the output terminal of the third-stage transistor are all connected to the VCM common-mode voltage to reset the circuit, so as to eliminate the signals that may remain in the previous amplification process, avoid interference or errors to the next amplification, and wait for the next amplification phase.

[0078] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A ring amplifier, characterized in that: The ring amplifier comprises: a multi-stage amplification circuit and a level shift circuit; The input end of the multi-stage amplifier circuit is connected to the signal input end of the ring amplifier, and the output end of the multi-stage amplifier circuit is connected to the first end of the level shift circuit; the second end of the level shift circuit is connected to the signal output end of the ring amplifier; The level shift circuit includes a first switch, a second switch, a third switch and a third capacitor. The first end of the level shift circuit is connected to the second end of the level shift circuit through the first switch; the second end of the level shift circuit is connected to the first end of the third capacitor; and the first end of the level shift circuit is connected to the second end of the third capacitor through the second switch.

2. The ring amplifier according to claim 1, characterized in that: The second end of the third capacitor is also connected to the common mode voltage end through a third switch, and the common mode voltage end is used to reset the circuit of the ring amplifier.

3. The ring amplifier according to claim 1 or 2, characterized in that: The multi-stage amplifier circuit includes a cascaded first-stage amplifier circuit, a second-stage amplifier circuit and a third-stage amplifier circuit; the first-stage amplifier circuit, the second-stage amplifier circuit and the third-stage amplifier circuit all include a plurality of switch tubes.

4. The ring amplifier according to claim 3, characterized in that: The first-stage amplifier circuit includes a first switch tube and a second switch tube. The signal input end of the ring amplifier is connected to the input end of the first-stage amplifier circuit through a first capacitor. The input end of the first-stage amplifier circuit is connected to the control end of the first switch tube and the control end of the second switch tube respectively. In the first-stage amplifier circuit, the power supply voltage terminal is connected to the output terminal of the first-stage amplifier circuit through the first switch tube; the output terminal of the first-stage amplifier circuit is grounded through the second switch tube.

5. The ring amplifier according to claim 4, characterized in that: The second stage amplifying circuit includes a third switch tube, a fourth switch tube and a first resistor; The output end of the first-stage amplifier circuit is connected to the input end of the second-stage amplifier circuit; the input end of the second-stage amplifier circuit is connected to the control end of the first switch tube and the control end of the second switch tube respectively; In the second-stage amplifier circuit, the power supply voltage terminal is connected to the first end of the first resistor through the third switch tube; the second end of the first resistor is grounded through the fourth switch tube.

6. The ring amplifier according to claim 5, characterized in that: The third-stage amplifier circuit includes a fifth switch tube and a sixth switch tube; the first end of the first resistor is connected to the control end of the fifth switch tube; the second end of the first resistor is connected to the control end of the sixth switch tube; In the third-stage amplifier circuit, the power supply voltage terminal is connected to the output terminal of the third-stage amplifier circuit through the fifth switch tube; the output terminal of the third-stage amplifier circuit is grounded through the sixth switch tube.

7. The ring amplifier according to claim 4, characterized in that: The ring amplifier also includes a second capacitor; One end of the second capacitor is connected to the first capacitor, and the other end of the second capacitor is connected to the signal output end of the ring amplifier.

8. A pipelined successive approximation analog-to-digital converter, characterized in that: The invention comprises the ring amplifier according to any one of claims 1 to 7.

9. A voltage amplification method, characterized in that: Applied to the ring amplifier according to any one of claims 1 to 7, the method comprising: The first switch and the third switch are closed, and the second switch is opened, so that the third-stage amplifier circuit is turned on and performs a first amplification on the input signal; The second switch is closed, and the first switch and the third switch are opened, so that the third-stage amplifier circuit amplifies the input signal for the second time through the third capacitor coupling.

10. The method according to claim 9, characterized in that The method further includes: connecting the signal input terminal of the ring amplifier, the signal output terminal of the ring amplifier, and the third-stage amplifier circuit to a common mode voltage, so as to reset the circuit of the ring amplifier.

Images