Tracking and holding amplifier

Abstract

The invention discloses a track and hold amplifier. The tracking and holding amplifier comprises an input buffer module with a switch, which is used for amplifying and outputting an input signal according to a first control signal and cutting off the output according to a second control signal; the switch emitter following module is connected with the input buffer module with the switch and is used for switching on output according to the third control signal, switching off the output according to the fourth control signal and outputting along with the input buffer module with the switch when the output is switched on; the emitter following module is connected with the switch emitter following module and is used for following output when the switch emitter following module opens the output and storing the voltage output by the switch emitter following module; and when the switch emitter following module cuts off the output, the output is carried out according to the stored voltage. The sampling precision of the tracking and holding amplifier is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a tracking and holding amplifier. Background Art

[0002] As the requirements of integrated circuits for signal acquisition continue to increase, the sampling requirements of integrated circuits for track-and-hold amplifiers are also increasing. However, the track-and-hold amplifiers used in the prior art are prone to signal crosstalk during operation, especially during the switching between the tracking mode and the holding mode, and have low sampling accuracy. Summary of the invention

[0003] The invention provides a tracking and holding amplifier to improve the sampling accuracy of the tracking and holding amplifier.

[0004] According to one aspect of the present invention, there is provided a track-and-hold amplifier, comprising:

[0005] An input buffer module with a switch, used to amplify and output an input signal according to a first control signal, and shut down the output according to a second control signal;

[0006] A switch emitter follower module, connected to the switch input buffer module, used to turn on the output according to the third control signal and turn off the output according to the fourth control signal, and to follow the switch input buffer module to output when the output is turned on;

[0007] The emitter follower module is connected to the switch emitter follower module and is used to follow the output when the switch emitter follower module turns on the output and store the voltage output by the switch emitter follower module; when the switch emitter follower module turns off the output, output according to the stored voltage.

[0008] Optionally, the switch input buffer module comprises: an amplifying unit, a first switch unit and a first load; the amplifying unit is connected to the first load through the first switch unit; the connection between the first switch unit and the first load is connected to the switch emitter follower module; the first switch unit and the first load are symmetrically provided with a second switch unit and a second load;

[0009] The switch input buffer module further includes: a third switch unit and a third load; the amplifying unit is connected to the third load through the third switch unit; the connection between the third switch unit and the third load is connected to the switch emitter follower module; the third switch unit and the third load are symmetrically provided with a fourth switch unit and a fourth load;

[0010] The first switch unit and the third switch unit are used to be turned on according to the first control signal and output the input signal to the switch emitter follower module; the second switch unit and the fourth switch unit are used to be turned on according to the second control signal, the second switch unit outputs the input signal to the second load, and the fourth switch unit outputs the input signal to the fourth load.

[0011] Optionally, the amplification unit includes:

[0012] A first triode and a second triode, wherein the first triode and the second triode are used to receive and amplify an input signal;

[0013] a first resistor and a second resistor, wherein a first end of the first resistor is connected to a second end of the first transistor, and a first end of the second resistor is connected to a second end of the second transistor;

[0014] a first current source, wherein a first end of the first current source is connected to a second end of the first resistor, and the first end of the first current source is also connected to a second end of the second resistor; and a second end of the first current source is connected to a second power line;

[0015] The first switch unit includes: a third triode, a second end of the third triode is connected to the first end of the first triode;

[0016] The first load comprises: a third resistor, a first end of the third resistor is connected to the first power line, and a second end of the third resistor is connected to the first end of the third transistor;

[0017] The second switch unit includes: a fourth transistor, a second end of the fourth transistor is connected to the first end of the first transistor;

[0018] The second load comprises: a fourth resistor, a first end of the fourth resistor is connected to the first power line, and a second end of the fourth resistor is connected to the first end of the fourth transistor;

[0019] The third switch unit includes: a fifth transistor, a second end of the fifth transistor is connected to the first end of the second transistor;

[0020] The third load comprises: a fifth resistor, a first end of the fifth resistor is connected to the first power line, and a second end of the fifth resistor is connected to the first end of the fifth transistor;

[0021] The fourth switch unit includes: a sixth triode, a second end of the sixth triode is connected to the first end of the second triode;

[0022] The fourth load includes: a sixth resistor, a first end of the sixth resistor is connected to the first power line, and a second end of the sixth resistor is connected to the first end of the sixth transistor.

[0023] Optionally, the switch emitter follower module includes:

[0024] A first signal following unit, connected to the first power line and the input buffer module with switch, and configured to follow the input buffer module with switch to output when turned on;

[0025] a first switch branch, connected to the first signal following unit, and configured to open the first signal following unit according to the third control signal;

[0026] a second switch branch, connected to the first signal following unit, and configured to turn off the first signal following unit according to the fourth control signal;

[0027] a second current source connected between the first switch branch and the second power line; and also connected between the second switch branch and the second power line;

[0028] The first signal following unit, the first switch branch, the second switch branch and the second current source are symmetrically provided with a second signal following unit, a third switch branch, a fourth switch branch and a third current source respectively.

[0029] Optionally, the first signal follower unit includes: a seventh transistor, a first end of the seventh transistor is connected to the first power line, and a control end of the seventh transistor is connected to the input buffer module with switch;

[0030] The first switch branch includes: an eighth triode and a ninth triode; the first end of the eighth triode is connected to the second end of the seventh triode, the second end of the eighth triode is connected to the first end of the ninth triode; the second end of the ninth triode is connected to the first end of the second current source; the ninth triode is used to be turned on according to the third control signal;

[0031] The second switch branch includes: a tenth transistor and an eleventh transistor; the first end of the tenth transistor is connected to the control end of the seventh transistor, the second end of the tenth transistor is connected to the first end of the eleventh transistor; the second end of the eleventh transistor is connected to the first end of the second current source; the eleventh transistor is used to be turned on according to the fourth control signal;

[0032] The second signal follower unit comprises: a twelfth transistor, a first end of the twelfth transistor is connected to the first power line, and a control end of the twelfth transistor is connected to the switch input buffer module;

[0033] The third switch branch includes: a thirteenth triode and a fourteenth triode; the first end of the thirteenth triode is connected to the second end of the twelfth triode, the second end of the thirteenth triode is connected to the first end of the fourteenth triode; the second end of the fourteenth triode is connected to the first end of the third current source; the fourteenth triode is used to be turned on according to the third control signal;

[0034] The fourth switch branch includes: a fifteenth transistor and a sixteenth transistor; the first end of the fifteenth transistor is connected to the control end of the twelfth transistor, and the second end of the fifteenth transistor is connected to the first end of the sixteenth transistor; the second end of the sixteenth transistor is connected to the first end of the third current source; the sixteenth transistor is used to be turned on according to the fourth control signal.

[0035] Optionally, the switch emitter follower module further includes:

[0036] a seventeenth triode, wherein a first end of the seventeenth triode is connected to a second end of the tenth triode, and the seventeenth triode is used to be turned on according to a fifth control signal; and a turn-on time of the seventeenth triode is faster than a turn-on time of the eleventh triode;

[0037] a seventh resistor, wherein a first end of the seventh resistor is connected to a second end of the seventeenth transistor, and a second end of the seventh resistor is connected to a second power line;

[0038] an eighteenth triode, wherein a first end of the eighteenth triode is connected to a second end of the fifteenth triode, and the eighteenth triode is used to be turned on according to a fifth control signal; and a turn-on time of the eighteenth triode is faster than a turn-on time of the sixteenth triode;

[0039] An eighth resistor, wherein a first end of the eighth resistor is connected to a second end of the eighteenth transistor, and a second end of the eighth resistor is connected to a second power line.

[0040] Optionally, the emitter follower module includes:

[0041] a first capacitor, wherein a first end of the first capacitor is connected to a first power line, and a second end of the first capacitor is connected to the switch emitter follower module; the first capacitor is used to follow the output when the switch emitter follower module is turned on, and store the voltage output by the switch emitter follower module; when the switch emitter follower module is turned off, output is performed according to the stored voltage;

[0042] a nineteenth triode, wherein a first end of the nineteenth triode is connected to the first power line, and a control end of the nineteenth triode is connected to the second end of the first capacitor;

[0043] a fourth current source, wherein a first end of the fourth current source is connected to a second end of the nineteenth transistor, and a second end of the fourth current source is connected to a second power line;

[0044] a second capacitor, wherein a first end of the second capacitor is connected to the first power line, and a second end of the second capacitor is connected to the switch emitter follower module; the second capacitor is used to follow the output when the switch emitter follower module is turned on, and store the voltage output by the switch emitter follower module; when the switch emitter follower module is turned off, output according to the stored voltage;

[0045] A twenty-third transistor, a first end of the second third transistor is connected to the first power line, and a control end of the second third transistor is connected to the second end of the second capacitor;

[0046] A fifth current source, wherein a first end of the fifth current source is connected to a second end of the second triode, and a second end of the fifth current source is connected to a second power line.

[0047] Optionally, the track-and-hold amplifier further includes:

[0048] The feedback buffer module is connected between the switch input buffer module and the second power line, and is also connected to the emitter follower module. The feedback buffer module is used to stabilize the signal input from the switch input buffer module to the switch emitter follower module.

[0049] Optionally, the feedback buffer module includes:

[0050] a twenty-first triode, a first end of the twenty-first triode being connected to the first end of the second load, and the twenty-first triode being configured to be turned on according to the first control signal;

[0051] a twenty-second triode, a first end of the twenty-second triode being connected to the first end of the first load, and the twenty-second triode being configured to be turned on according to the second control signal;

[0052] A twenty-third triode, a first end of the twenty-third triode being connected to the second end of the twenty-first triode and the second end of the twenty-second triode respectively;

[0053] a ninth resistor, a first end of the ninth resistor being connected to the second end of the twenty-third transistor;

[0054] a twenty-fourth triode, a first end of the twenty-fourth triode being connected to the first end of the fourth load, and the twenty-fourth triode being configured to be turned on according to the first control signal;

[0055] a twenty-fifth triode, a first end of the twenty-fifth triode being connected to the first end of the third load, and the twenty-fifth triode being configured to be turned on according to the second control signal;

[0056] A twenty-sixth triode, a first end of the twenty-sixth triode being connected to the second end of the twenty-fourth triode and the second end of the twenty-fifth triode respectively;

[0057] a tenth resistor, a first end of the tenth resistor being connected to the second end of the twenty-sixth transistor;

[0058] A fifth current source is connected between the ninth resistor and the second power line, and the fifth current source is also connected between the tenth resistor and the second power line.

[0059] Optionally, the signal transmission branch further includes: an anti-leakage module, used to filter out the leakage signal output by the switch emitter follower module; the anti-leakage module includes a first anti-leakage unit and a second anti-leakage unit;

[0060] The first end of the first anti-leakage unit is connected to the second end of the seventh transistor, and the second end of the first anti-leakage unit is connected to the control end of the twelfth transistor;

[0061] The first end of the second anti-leakage unit is connected to the second end of the twelfth transistor, and the second end of the second anti-leakage unit is connected to the control end of the seventh transistor;

[0062] The first anti-leakage unit comprises:

[0063] a twenty-seventh triode, a twenty-eighth triode, a twenty-ninth triode and a thirty-third triode; the second end of the twenty-seventh triode is connected to the second end of the twenty-eighth triode, the first end of the twenty-eighth triode is connected to the first end of the thirty-third triode, the second end of the thirty-third triode is connected to the second end of the twenty-ninth triode, the first end of the twenty-ninth triode is connected to the first end of the twenty-seventh triode, the control end of the twenty-seventh triode is connected to the control end of the twenty-ninth triode, and the control end of the twenty-eighth triode is connected to the control end of the thirty-third triode;

[0064] The connection point between the control end of the twenty-seventh transistor and the control end of the twenty-ninth transistor is connected to the second end of the seventh transistor; the connection point between the control end of the twenty-eighth transistor and the control end of the thirty-third transistor is connected to the control end of the twelfth transistor;

[0065] The second anti-leakage unit comprises:

[0066] A thirty-first triode, a thirty-second triode, a thirty-third triode and a thirty-fourth triode; the second end of the thirty-first triode is connected to the second end of the thirty-second triode, the first end of the thirty-second triode is connected to the first end of the thirty-fourth triode, the second end of the thirty-fourth triode is connected to the second end of the thirty-third triode, the first end of the thirty-third triode is connected to the first end of the thirty-first triode, the control end of the thirty-first triode is connected to the control end of the thirty-third triode, and the control end of the thirty-second triode is connected to the control end of the thirty-fourth triode;

[0067] The connection between the control end of the thirty-first transistor and the control end of the thirty-third transistor is connected to the control end of the seventh transistor; the connection between the control end of the thirty-second transistor and the control end of the thirty-fourth transistor is connected to the second end of the twelfth transistor.

[0068] The technical solution provided by the embodiment of the present invention is that in the tracking mode, the switch input buffer module can amplify and output the input signal according to the first control signal, and the switch emitter follower module can be turned on according to the third control signal and input the signal output by the switch input buffer module into the emitter follower module. When the tracking mode is switched to the holding mode, the switch input buffer module can stop the output of the signal according to the second control signal, and at the same time, the switch emitter follower module is turned off according to the fourth control signal, which further prevents the signal from being input into the emitter follower module, reduces the input crosstalk to the emitter follower module, and improves the sampling accuracy of the signal and the performance of the tracking and holding amplifier.

[0069] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0071] Figure 1 is a structural schematic diagram of a track-and-hold amplifier provided according to an embodiment of the present invention;

[0072] Figure 2 is a schematic diagram of the structure of another track-and-hold amplifier provided according to an embodiment of the present invention;

[0073] Figure 3 is a structural schematic diagram of another tracking and holding amplifier provided according to an embodiment of the present invention;

[0074] Figure 4 is a structural schematic diagram of another tracking and holding amplifier provided according to an embodiment of the present invention;

[0075] Figure 5 is a schematic diagram of a voltage conversion from a tracking to a holding phase provided according to an embodiment of the present invention;

[0076] Figure 6 It is a schematic diagram of voltage conversion from tracking to holding stage provided by the prior art;

[0077] Figure 7 4 is a schematic diagram of the structure of another track-and-hold amplifier provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0078] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0079] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0080] An embodiment of the present invention provides a track-and-hold amplifier. Figure 1 A schematic diagram of the structure of a tracking and holding amplifier provided by an embodiment of the present invention. Figure 1The tracking and holding amplifier includes: a switch input buffer module 1, a switch emitter follower module 2 and an emitter follower module 3. The switch input buffer module 1 is used to amplify and output the input signal according to the first control signal, and to shut down the output according to the second control signal. The switch emitter follower module 2 is connected to the switch input buffer module 1, and is used to turn on the output according to the third control signal, and to shut down the output according to the fourth control signal, and to follow the switch input buffer module 1 to output when the output is turned on. The emitter follower module 3 is connected to the switch emitter follower module 2, and is used to follow the output when the switch emitter follower module 2 turns on the output, and to store the voltage output by the switch emitter follower module 2; when the switch emitter follower module 2 shuts off the output, the output is performed according to the stored voltage.

[0081] The tracking and holding amplifier is an amplifier that can be switched in different working modes. When the tracking and holding amplifier is in the tracking mode, the switch input buffer module 1 can receive the first control signal and be turned on according to the first control signal. At this time, the switch input buffer module 1 amplifies the input signal and outputs it to the switch emitter follower module 2.

[0082] When the switch emitter follower module 2 receives the third control signal, the switch emitter follower module 2 is turned on. The switch emitter follower module 2 can follow the output signal of the switch input buffer module 1 in real time for output. Exemplarily, the conduction degree of the switch emitter follower module 2 can be inversely proportional to the input signal strength, and the input signal can be a voltage signal. When the input signal voltage is higher, the conduction degree of the switch emitter follower module 2 decreases, and when the voltage is lower, the conduction degree of the switch emitter follower module 2 increases. Therefore, the switch emitter follower module 2 can flip the input signal and reversely follow the input signal. The emitter follower module 3 receives the signal output by the switch emitter follower module 2 and outputs it, and at the same time, stores the voltage output by the switch emitter follower module 2.

[0083] When the track-and-hold amplifier is in the hold mode, the switch input buffer module 1 can receive the second control signal, and the first control signal stops inputting. At this time, the switch input buffer module 1 is turned off, and the input signal is retained in the switch input buffer module 1, and is not output to the switch emitter follower module 2. At the same time, the switch emitter follower module 2 receives the fourth control signal, and the switch emitter follower module 2 is turned off, further preventing the input of the signal. At this time, the emitter follower module 3 cannot receive the signal output by the switch emitter follower module 2, and outputs according to the voltage stored in the tracking mode.

[0084] According to the technical solution provided by the embodiment of the present invention, in the tracking mode, the switch input buffer module 1 can amplify and output the input signal according to the first control signal, and the switch emitter follower module 2 can be turned on according to the third control signal and input the signal output by the switch input buffer module 1 into the emitter follower module 3. When the tracking mode is switched to the holding mode, the switch input buffer module 1 can stop the output of the signal according to the second control signal, and at the same time, the switch emitter follower module 2 is turned off according to the fourth control signal, which further prevents the signal from being input into the emitter follower module 3, reduces the input crosstalk to the emitter follower module 3, and improves the sampling accuracy of the signal and the performance of the tracking and holding amplifier.

[0085] Figure 2 A schematic diagram of another track-and-hold amplifier provided by an embodiment of the present invention. Figure 2 On the basis of the above embodiments, optionally, the input buffer module 1 with switch includes: an amplifier unit 11, a first switch unit 12 and a first load 13; the amplifier unit 11 is connected to the first load 13 through the first switch unit 12; the connection between the first switch unit 12 and the first load 13 is connected to the switch emitter follower module 2; the first switch unit 12 and the first load 13 are symmetrically provided with a second switch unit 14 and a second load 15. The input buffer module 1 with switch also includes: a third switch unit 16 and a third load 17; the amplifier unit 11 is connected to the third load 17 through the third switch unit 16; the connection between the third switch unit 16 and the third load 17 is connected to the switch emitter follower module 2; the third switch unit 16 and the third load 17 are symmetrically provided with a fourth switch unit 18 and a fourth load 19. The first switch unit 12 and the third switch unit 16 are used to be turned on according to the first control signal and output the input signal to the switch emitter follower module 2; the second switch unit 14 and the fourth switch unit 18 are used to be turned on according to the second control signal, the second switch unit 14 outputs the input signal to the second load 15, and the fourth switch unit 18 outputs the input signal to the fourth load 19.

[0086] The amplifying unit 11 may be used to receive an input signal and amplify the signal. Exemplarily, the amplifying unit 11 may receive two input signals at the same time, and the two input signals may be a pair of differential signals.

[0087] When the track-and-hold amplifier is in the tracking mode, the first switch unit 12 and the third switch unit 16 receive the first control signal and are turned on, and the amplifier unit 11 inputs the amplified differential signal into the switch emitter follower module 2 through the first switch unit 12 and the third switch unit 16. When the track-and-hold amplifier is in the holding mode, the first switch unit 12 and the third switch unit 16 cannot receive the first control signal and are turned off, the second switch unit 14 and the fourth switch unit 18 receive the second control signal and are turned on, and the amplifier unit 11 inputs the amplified signal into the second load 15 through the second switch unit 14 and into the fourth load 19 through the fourth switch unit 18. Since neither the second load 15 nor the fourth load 19 forms a path with the switch emitter follower module 2, the signal input by the switch input buffer module 1 will not be transmitted to the switch emitter follower module 2. Through this setting, it is avoided that the signal input by the switch input buffer module 1 affects the voltage stored in the emitter follower module 3 after the tracking mode is switched to the holding mode, and the input crosstalk to the emitter follower module 3 is reduced.

[0088] Continue to refer Figure 2On the basis of the above embodiments, optionally, the amplification unit 11 includes: a first triode Q1 and a second triode Q2, the first triode Q1 and the second triode Q2 are used to receive and amplify input signals. A first resistor R1 and a second resistor R2, the first end of the first resistor R1 is connected to the second end of the first triode Q1, and the first end of the second resistor R2 is connected to the second end of the second triode Q2. A first current source ISEF1, the first end of the first current source ISEF1 is connected to the second end of the first resistor R1, and the first end of the first current source ISEF1 is also connected to the second end of the second resistor R2; the second end of the first current source ISEF1 is connected to the second power line. The first switch unit 12 includes: a third triode Q3, the second end of the third triode Q3 is connected to the first end of the first triode Q1. The first load 13 includes: a third resistor R3, the first end of the third resistor R3 is connected to the first power line, and the second end of the third resistor R3 is connected to the first end of the third triode Q3. The second switch unit 14 includes: a fourth transistor Q4, the second end of the fourth transistor Q4 is connected to the first end of the first transistor Q1. The second load 15 includes: a fourth resistor R4, the first end of the fourth resistor R4 is connected to the first power line, and the second end of the fourth resistor R4 is connected to the first end of the fourth transistor Q4. The third switch unit 16 includes: a fifth transistor Q5, the second end of the fifth transistor Q5 is connected to the first end of the second transistor. The third load 17 includes: a fifth resistor R5, the first end of the fifth resistor R5 is connected to the first power line, and the second end of the fifth resistor R5 is connected to the first end of the fifth transistor Q5. The fourth switch unit 18 includes: a sixth transistor Q6, the second end of the sixth transistor Q6 is connected to the first end of the second transistor Q2. The fourth load 19 includes: a sixth resistor R6, the first end of the sixth resistor R6 is connected to the first power line, and the second end of the sixth resistor R6 is connected to the first end of the sixth transistor Q6.

[0089] Among them, the first power line can be connected to the positive electrode of the power supply (VCC, Voltage Common Collector), and the second power line can be connected to the negative electrode of the power supply (VEE, Voltage Common Emitter). The first transistor Q1 and the second transistor Q2 are used to receive and amplify the input signal, and the first resistor R1 and the second resistor R2 can be used as feedback resistors to reduce the nonlinear distortion in the line and improve the linearity of the circuit, so that the switch input buffer module 1 can more accurately reflect the changes in the input signal. When the tracking and holding amplifier is in the tracking mode, the third transistor Q3 and the fifth transistor Q5 are turned on due to receiving the first control signal, and the input signal received by the first transistor Q1 can be input into the switch emitter follower module 2 through the third transistor Q3, and the input signal received by the second transistor Q2 can be input into the switch emitter follower module 2 through the fifth transistor Q5.

[0090] When the tracking and holding amplifier is in the holding mode, the third transistor Q3 and the fifth transistor Q5 are turned off because they cannot receive the first control signal, and the fourth transistor Q4 and the sixth transistor Q6 are turned on because they receive the second control signal. The input signal received by the first transistor Q1 can be input into the fourth resistor R4 through the fourth transistor Q4. Since there is no path between the fourth resistor R4 and the switch emitter follower module 2, the input signal will be maintained in the fourth resistor R4. The input signal received by the second transistor Q2 can be input into the sixth resistor R6 through the sixth transistor Q6. Since there is no path between the sixth resistor R6 and the switch emitter follower module 2, the input signal will be maintained in the sixth resistor R6.

[0091] Continue to refer Figure 2 On the basis of the above embodiments, optionally, the switch emitter follower module 2 includes: a first signal follower unit 21, a first switch branch 22, a second switch branch 23 and a second current source ISEF2. The first signal follower unit 21 is connected to the first power line and the switch input buffer module 1, and is used to follow the switch input buffer module 1 to output when turned on. The first switch branch 22 is connected to the first signal follower unit 21, and is used to turn on the first signal follower unit 21 according to the third control signal. The second switch branch 23 is connected to the first signal follower unit 21, and is used to turn off the first signal follower unit 21 according to the fourth control signal. The second current source ISEF2 is connected between the first switch branch 22 and the second power line; and is also connected between the second switch branch 23 and the second power line. The first signal follower unit 21, the first switch branch 22, the second switch branch 23 and the second current source ISEF2 are symmetrically provided with a second signal follower unit 24, a third switch branch 25, a fourth switch branch 26 and a third current source ISEF3 respectively.

[0092] When the track-and-hold amplifier is in the tracking mode, the first switch branch 22 and the third switch branch 25 receive the third control signal and are turned on. When the first switch branch 22 is turned on, a path is formed between the first power line, the first signal follower unit 21, the first switch branch 22, the second current source ISEF2, and the second power line, the first signal follower unit 21 is turned on, and the signal output by the third transistor Q3 can be input into the switch emitter follower module 2 through the first signal follower unit 21. At the same time, a path is formed between the first power line, the second signal follower unit 24, the third switch branch 25, the third current source ISEF3, and the second power line, the second signal follower unit 24 is also turned on, and the signal output by the fifth transistor Q5 can be input into the switch emitter follower module 2 through the second signal follower unit 24.

[0093] When the track-and-hold amplifier is in the hold mode, the first switch branch 22 and the third switch branch 25 cannot receive the third control signal and are turned off, and the second switch branch 23 and the fourth switch branch 26 receive the fourth control signal and are turned on. When the second switch branch 23 is turned on, a path is formed between the first power line, the third resistor R3, the second switch branch 23, the second current source ISEF2 and the second power line, and the first signal follower unit 21 cannot form a path and is turned off, thereby cutting off the signal input of the switch emitter follower module 2. At the same time, a path is formed between the first power line, the fifth resistor R5, the fourth switch branch 26, the third current source ISEF3 and the second power line, and the second signal follower unit 24 cannot form a path and is turned off, thereby cutting off the signal input of the switch emitter follower module 2.

[0094] The embodiment of the present invention sets a first switch branch 22, a second switch branch 23, a third switch branch 25 and a fourth switch branch 26. In the tracking mode, the switch emitter follower module 2 can receive the input signal through the first switch branch 22 and the third switch branch 25, and in the holding mode, the switch emitter follower module 2 cannot receive the input signal through the second switch branch 23 and the fourth switch branch 26. The switch control of the switch emitter follower module 2 is realized, and a good control effect is achieved.

[0095] Continue to refer Figure 2On the basis of the above embodiments, optionally, the first signal follower unit 21 includes: a seventh transistor Q7, a first end of the seventh transistor Q7 is connected to the first power line, and a control end of the seventh transistor Q7 is connected to the switch input buffer module 1. The first switch branch 22 includes: an eighth transistor Q8 and a ninth transistor Q9; a first end of the eighth transistor Q8 is connected to the second end of the seventh transistor Q7, and a second end of the eighth transistor Q8 is connected to a first end of the ninth transistor Q9; a second end of the ninth transistor Q9 is connected to a first end of the second current source ISEF2; and the ninth transistor Q9 is used to be turned on according to the third control signal. The second switch branch 23 includes: a 11th transistor Q10 and an 11th transistor Q11; the first end of the 11th transistor Q10 is connected to the control end of the 7th transistor Q7, the second end of the 11th transistor Q10 is connected to the first end of the 11th transistor Q11; the second end of the 11th transistor Q11 is connected to the first end of the second current source ISEF2; the 11th transistor Q11 is used to be turned on according to the fourth control signal. The second signal follower unit 24 includes: a 12th transistor Q12, the first end of the 12th transistor Q12 is connected to the first power line, and the control end of the 12th transistor Q12 is connected to the switch input buffer module 1. The third switch branch 25 includes: a thirteenth transistor Q13 and a fourteenth transistor Q14; the first end of the thirteenth transistor Q13 is connected to the second end of the twelfth transistor Q12, the second end of the thirteenth transistor Q13 is connected to the first end of the fourteenth transistor Q14; the second end of the fourteenth transistor Q14 is connected to the first end of the third current source ISEF3; the fourteenth transistor Q14 is used to be turned on according to the third control signal. The fourth switch branch 26 includes: a fifteenth transistor Q15 and a sixteenth transistor Q16; the first end of the fifteenth transistor Q15 is connected to the control end of the twelfth transistor Q12, the second end of the fifteenth transistor Q15 is connected to the first end of the sixteenth transistor Q16; the second end of the sixteenth transistor Q16 is connected to the first end of the third current source ISEF3; the sixteenth transistor Q16 is used to be turned on according to the fourth control signal.

[0096] Among them, when the tracking and holding amplifier is in the tracking mode, the signal output by the third transistor Q3 can be output to the seventh transistor Q7 and the third resistor R3. Exemplarily, the output signal can be a voltage signal. When the output signal strength is greater, the voltage drop generated by the third resistor R3 is greater, and the voltage at the first end of the third resistor R3 is a fixed value, so that the voltage input to the control end of the seventh transistor Q7 is reduced, and the opening degree of the seventh transistor Q7 is reduced. Therefore, the seventh transistor Q7 can flip the input signal and output it to the emitter follower module 3.

[0097] The signal output by the fifth transistor Q5 can be output to the twelfth transistor Q12 and the fifth resistor R5. When the output signal strength is greater, the voltage drop generated by the fifth resistor R5 is greater, so that the voltage input to the control end of the twelfth transistor Q12 is reduced, and the opening degree of the twelfth transistor Q12 is reduced. Therefore, the twelfth transistor Q12 can flip the input signal and output it to the emitter follower module 3.

[0098] Figure 3 A schematic diagram of the structure of another tracking and holding amplifier provided by an embodiment of the present invention. Figure 3 On the basis of the above embodiments, optionally, the switch emitter follower module 2 further includes: a seventeenth transistor Q17, a seventh resistor R7, an eighteenth transistor and an eighth resistor R8. The first end of the seventeenth transistor Q17 is connected to the second end of the tenth transistor Q110, and the seventeenth transistor Q17 is used to be turned on according to the fifth control signal; the turn-on time of the seventeenth transistor Q17 is faster than the turn-on time of the eleventh transistor Q11. The first end of the seventh resistor R7 is connected to the second end of the seventeenth transistor, and the second end of the seventh resistor is connected to the second power line. The first end of the eighteenth transistor Q18 is connected to the second end of the fifteenth transistor Q15, and the eighteenth transistor Q18 is used to be turned on according to the fifth control signal; the turn-on time of the eighteenth transistor Q18 is faster than the turn-on time of the sixteenth transistor Q16. The first end of the eighth resistor R8 is connected to the second end of the eighteenth transistor Q18, and the second end of the eighth resistor R8 is connected to the second power line.

[0099] Among them, when the tracking mode and the holding mode are switched, the ninth transistor Q9 is turned off and the eleventh transistor Q11 is turned on. However, it takes a certain time for the eleventh transistor Q11 to be turned on, so that the second switch branch 23 cannot be turned on instantly when the tracking mode is switched to the holding mode. Therefore, the voltage of the control end of the seventeenth transistor Q17 is adjusted by the fifth control signal, so that when the tracking mode is switched to the holding mode, the seventeenth transistor Q17 can be turned on instantly.

[0100] Specifically, in the tracking mode, the seventeenth transistor Q17 is in a weak conduction state, and the seventeenth transistor Q17 can transmit a current value of about 200μA. When the tracking mode switches to the holding mode, the seventeenth transistor Q17 is fully turned on according to the fifth control signal, and the seventeenth transistor Q17 can transmit a current value of about 2mA. Because the seventeenth transistor Q17 is not in a completely off state in the tracking mode, the seventeenth transistor Q17 has a faster conduction time. Then, a path is formed between the first power line, the third resistor R3, the tenth transistor Q10, the seventeenth transistor Q17, the seventh resistor R7 and the second power line. The seventh transistor Q7 cannot effectively form a loop, so that the seventh transistor Q7 can maintain a stable off state during the switching process between the tracking mode and the holding mode. Similarly, by setting the eighteenth transistor Q18, the twelfth transistor Q2 can also maintain a stable off state during the switching process between the tracking mode and the holding mode.

[0101] Continue to refer Figure 3 On the basis of the above embodiments, optionally, the emitter follower module 3 includes: a first capacitor C1, a nineteenth transistor Q19, a fourth current source ISEF4, a second capacitor C2, a twenty-third transistor Q20 and a fifth current source ISEF5. The first end of the first capacitor C1 is connected to the first power line, and the second end of the first capacitor C1 is connected to the switch emitter follower module 2; the first capacitor C1 is used to follow the output when the switch emitter follower module 2 is turned on, and store the voltage output by the switch emitter follower module 2; when the switch emitter follower module 2 is turned off, the output is performed according to the stored voltage. The first end of the nineteenth transistor Q19 is connected to the first power line, and the control end of the nineteenth transistor Q19 is connected to the second end of the first capacitor C1. The first end of the fourth current source ISEF4 is connected to the second end of the nineteenth transistor Q19, and the second end of the fourth current source ISEF4 is connected to the second power line. The first end of the second capacitor C2 is connected to the first power line, and the second end of the second capacitor C2 is connected to the switch emitter follower module 2; the second capacitor C2 is used to follow the output when the switch emitter follower module 2 is turned on, and store the voltage output by the switch emitter follower module 2; when the switch emitter follower module 2 is turned off, the output is performed according to the stored voltage. The first end of the twenty-third transistor Q20 is connected to the first power line, and the control end of the twenty-third transistor Q20 is connected to the second end of the second capacitor C2. The first end of the fifth current source ISEF5 is connected to the second end of the twenty-third transistor Q20, and the second end of the fifth current source ISEF5 is connected to the second power line.

[0102] Wherein, when the tracking and holding amplifier is in the tracking mode, the signal output by the seventh transistor Q7 is transmitted to the nineteenth transistor Q19 through the second end of the first capacitor C1, and the signal is output by the nineteenth transistor Q19. The first end of the first capacitor C1 is connected to the first power line, so the first end and the second end of the first capacitor C1 have a certain voltage difference, and the first capacitor C1 is charged according to the voltage difference to store the voltage output by the seventh transistor Q7. At the same time, the signal output by the twelfth transistor Q12 is transmitted to the twenty-third transistor Q20 through the second end of the second capacitor C2, and the signal is output by the twenty-third transistor Q20. The second capacitor C2 is charged to store the voltage output by the twelfth transistor Q12.

[0103] When the track-and-hold amplifier is in the hold mode, the first capacitor C1 and the second capacitor C2 output according to the stored voltage.

[0104] Figure 4 A schematic diagram of the structure of another tracking and holding amplifier provided by an embodiment of the present invention. Figure 4 On the basis of the above embodiments, optionally, the tracking and holding amplifier also includes: a feedback buffer module 4, which is connected between the switch input buffer module 1 and the second power line, and is also connected to the emitter follower module 3. The feedback buffer module is used to stabilize the signal of the switch input buffer module 1 input to the switch emitter follower module 2.

[0105] Among them, the feedback buffer module 4 can receive the signal output by the nineteenth transistor Q19 and the twenty-third transistor Q20. Exemplarily, when the tracking and holding amplifier is in the holding mode, the feedback buffer module 4 can feed back the signal output by the nineteenth transistor Q19 into the third resistor R3 through the feedback buffer module 4, so that the third resistor R3 generates a certain voltage drop. The signal output by the twenty-third transistor Q20 can also be fed back into the fifth resistor R5 through the feedback buffer module 4, so that the fifth resistor R5 generates a certain voltage drop. When the tracking and holding amplifier switches from the holding mode to the tracking mode, the third transistor Q3 and the fifth transistor Q5 are turned on, and the signal is input into the seventh transistor Q7 through the third transistor Q3, and is also input into the twelfth transistor Q12 through the fifth transistor Q5. Because the third resistor R3 and the fifth resistor R5 both have a certain voltage drop in the holding mode, when the holding mode is switched to the tracking mode, the voltages of the third resistor R3 and the fifth resistor R5 will not change suddenly, so that the opening degree of the seventh triode Q7 and the twelfth triode Q12 is maintained in a stable state. And the opening degree of the seventh triode Q7 and the twelfth triode Q12 can maintain a consistent change, thereby reducing the error of the output signal.

[0106] Figure 5A schematic diagram of voltage conversion from a tracking to a holding phase provided by an embodiment of the present invention is exemplarily shown. Figure 6 The schematic diagram of voltage conversion from tracking to holding stage provided by the prior art is shown as an example. Figure 5-Figure 6 , optionally, V b + is the voltage value of the input signal of the control terminal of the seventh transistor Q7, V b - is the voltage value of the input signal of the control terminal of the twelfth transistor Q12. 0-t1 is the tracking mode, and after t1 is the holding mode. When the tracking mode is switched to the holding mode, the prior art V b +The voltage difference is △V 2 , V b -The voltage difference is △V 1 , △V 1 and △V 2 There are different differences, so when the tracking mode is switched to the holding mode, the voltage transition values ​​between the two signals are different, which causes a sudden change in the output signal of the emitter follower module 3. In the present invention, the voltage difference of Vb+ and the voltage difference of Vb- are both △V, so when the tracking mode is switched to the holding mode, the voltage transition values ​​of the seventh transistor Q7 and the twelfth transistor Q12 are the same, and the output signal of the emitter follower module 3 will not suddenly change, thereby reducing the base error.

[0107] Continue to refer Figure 4On the basis of the above embodiments, optionally, the feedback buffer module 4 includes: a twenty-first transistor Q21, a twenty-second transistor Q22, a twenty-third transistor Q23, a ninth resistor R9, a twenty-fourth transistor Q24, a twenty-fifth transistor Q25, a twenty-sixth transistor Q26, a tenth resistor R10 and a sixth current source ISEF6. The first end f of the twenty-first transistor Q21 is connected to the first end f of the second load 15, and the twenty-first transistor Q21 is used to be turned on according to the first control signal. The first end e of the twenty-second transistor Q22 is connected to the first end e of the first load 13, and the twenty-second transistor Q22 is used to be turned on according to the second control signal. The first end of the twenty-third transistor Q23 is respectively connected to the second end of the twenty-first transistor Q21 and the second end of the twenty-second transistor Q22. The first end of the ninth resistor R9 is connected to the second end of the twenty-third transistor Q23. The first end c of the twenty-fourth triode Q24 is connected to the first end c of the fourth load 19, and the twenty-fourth triode Q24 is used to be turned on according to the first control signal. The first end d of the twenty-fifth triode Q25 is connected to the first end d of the fourth load 17, and the twenty-fifth triode Q25 is used to be turned on according to the second control signal. The first end of the twenty-sixth triode Q26 is respectively connected to the second end of the twenty-fourth triode Q24 and the second end of the twenty-fifth triode Q25. The first end of the tenth resistor R10 is connected to the second end of the twenty-sixth triode Q26. The sixth current source ISEF6 is connected between the ninth resistor R9 and the second power line, and the sixth current source ISEF6 is also connected between the tenth resistor R10 and the second power line.

[0108] Wherein, when the tracking and holding amplifier is in the holding mode, the control end b of the twenty-sixth transistor Q26 receives the signal output by the second end b of the twenty-third transistor Q20 through the fifth current source ISEF5 and is turned on, and the control end a of the twenty-third transistor Q23 receives the signal output by the nineteenth transistor Q19 through the second end a of the fourth current source ISEF4 and is turned on. At the same time, the twenty-second transistor Q22 and the twenty-fifth transistor Q25 receive the second control signal and are turned on. The twenty-second transistor Q22 transmits the signal output by the nineteenth transistor Q19 to the third resistor R3, and the twenty-fifth transistor Q25 transmits the signal output by the twenty-third transistor Q20 to the fifth resistor R5. The third resistor R3 further turns off the seventh transistor Q7 because it has a certain voltage drop. The fifth resistor R5 further turns off the twelfth transistor Q12 because it has a certain voltage drop. Furthermore, the voltage values ​​of the third resistor R3 and the fifth resistor R5 will not change suddenly when the holding mode is switched to the tracking mode, so that the output signals of the seventh transistor Q7 and the twelfth transistor Q12 will not change significantly due to the switching of the mode.

[0109] When the tracking and holding amplifier is switched to the tracking mode, the twenty-first transistor Q21 and the twenty-fourth transistor Q24 receive the first control signal and are turned on. The twenty-first transistor Q21 transmits the signal output by the nineteenth transistor Q19 to the fourth resistor R4, and the twenty-fourth transistor Q24 transmits the signal output by the twenty-third transistor Q20 to the sixth resistor R6. Therefore, the signal will not be transmitted to the seventh transistor Q7 and the twelfth transistor Q12, nor will it affect the seventh transistor Q7 and the twelfth transistor Q12.

[0110] Figure 7 A schematic diagram of the structure of another tracking and holding amplifier provided by an embodiment of the present invention. Figure 7On the basis of the above embodiments, optionally, the tracking and holding amplifier further includes: an anti-leakage module 5, which is used to filter out the leakage signal output by the switch emitter follower module 2; the anti-leakage module 5 includes a first anti-leakage unit 51 and a second anti-leakage unit 52. The first end of the first anti-leakage unit 51 is connected to the second end of the seventh triode Q7, and the second end of the first anti-leakage unit 51 is connected to the control end of the twelfth triode Q12. The first end of the second anti-leakage unit 52 is connected to the second end of the twelfth triode Q12, and the second end of the second anti-leakage unit 52 is connected to the control end of the seventh triode Q7. The first anti-leakage unit 51 includes: a twenty-seventh triode Q27, a twenty-eighth triode Q28, a twenty-ninth triode Q29 and a thirty-third triode Q30; the second end of the twenty-seventh triode Q27 is connected to the second end of the twenty-eighth triode Q28, the first end of the twenty-eighth triode Q28 is connected to the first end of the thirty-third triode Q30, the second end of the thirty-third triode Q30 is connected to the second end of the twenty-ninth triode Q29, the first end of the twenty-ninth triode Q29 is connected to the first end of the twenty-seventh triode Q27, the control end of the twenty-seventh triode Q27 is connected to the control end of the twenty-ninth triode Q29, and the control end of the twenty-eighth triode Q28 is connected to the control end of the thirty-third triode Q30. The connection between the control end of the twenty-seventh transistor Q27 and the control end of the twenty-ninth transistor Q29 is connected to the second end of the seventh transistor Q7; the connection between the control end of the twenty-eighth transistor Q28 and the control end of the thirty-third transistor Q30 is connected to the control end of the twelfth transistor Q12. The second anti-leakage unit 52 includes: a thirty-first triode Q31, a thirty-second triode Q32, a thirty-third triode Q33 and a thirty-fourth triode Q34; the second end of the thirty-first triode Q31 is connected to the second end of the thirty-second triode Q32, the first end of the thirty-second triode Q32 is connected to the first end of the thirty-fourth triode Q34, the second end of the thirty-fourth triode Q34 is connected to the second end of the thirty-third triode Q33, the first end of the thirty-third triode Q33 is connected to the first end of the thirty-first triode Q31, the control end of the thirty-first triode Q31 is connected to the control end of the thirty-third triode Q33, and the control end of the thirty-second triode Q32 is connected to the control end of the thirty-fourth triode Q34. The connection between the control end of the thirty-first transistor Q31 and the control end of the thirty-third transistor Q33 is connected to the control end of the seventh transistor Q7; the connection between the control end of the thirty-second transistor Q32 and the control end of the thirty-fourth transistor Q34 is connected to the second end of the twelfth transistor Q12.

[0111] Among them, the seventh transistor Q3 and the twelfth transistor Q12 have parasitic capacitance, which may cause the signal to feed through to the first capacitor C1 and the second capacitor C2. The first anti-leakage unit 51 simulates the size of the parasitic capacitance of the seventh transistor Q3 by connecting four transistors in series and parallel, and offsets the feed-through signal of the seventh transistor Q3 by inputting a reverse signal. The second anti-leakage unit 52 simulates the size of the parasitic capacitance of the twelfth transistor Q12 by connecting four transistors in series and parallel, and offsets the feed-through signal of the twelfth transistor Q12 by inputting a reverse signal. Through this setting, the signal feed-through can be effectively improved, so that the seventh transistor Q3 and the twelfth transistor Q12 will not be affected by the interference of the feed-through signal and affect the normal signal output.

[0112] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0113] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A track-and-hold amplifier, characterized in that: include: An input buffer module with a switch, used to amplify and output an input signal according to a first control signal, and shut down the output according to a second control signal; A switch emitter follower module, connected to the switch input buffer module, used to turn on the output according to the third control signal and turn off the output according to the fourth control signal, and to follow the switch input buffer module to output when the output is turned on; The emitter follower module is connected to the switch emitter follower module and is used to follow the output when the switch emitter follower module turns on the output and store the voltage output by the switch emitter follower module; when the switch emitter follower module turns off the output, output according to the stored voltage.

2. The track-and-hold amplifier according to claim 1, characterized in that: The switch input buffer module comprises: an amplifier unit, a first switch unit and a first load; the amplifier unit is connected to the first load through the first switch unit; the connection between the first switch unit and the first load is connected to the switch emitter follower module; the first switch unit and the first load are symmetrically provided with a second switch unit and a second load; The switch input buffer module further includes: a third switch unit and a third load; the amplifying unit is connected to the third load through the third switch unit; the connection between the third switch unit and the third load is connected to the switch emitter follower module; the third switch unit and the third load are symmetrically provided with a fourth switch unit and a fourth load; The first switch unit and the third switch unit are used to be turned on according to the first control signal and output the input signal to the switch emitter follower module; the second switch unit and the fourth switch unit are used to be turned on according to the second control signal, the second switch unit outputs the input signal to the second load, and the fourth switch unit outputs the input signal to the fourth load.

3. The track-and-hold amplifier according to claim 2, characterized in that: The amplification unit comprises: A first triode and a second triode, wherein the first triode and the second triode are used to receive and amplify an input signal; a first resistor and a second resistor, wherein a first end of the first resistor is connected to a second end of the first transistor, and a first end of the second resistor is connected to a second end of the second transistor; a first current source, wherein a first end of the first current source is connected to a second end of the first resistor, and the first end of the first current source is also connected to a second end of the second resistor; and a second end of the first current source is connected to a second power line; The first switch unit includes: a third triode, a second end of the third triode is connected to the first end of the first triode; The first load comprises: a third resistor, a first end of the third resistor is connected to the first power line, and a second end of the third resistor is connected to the first end of the third transistor; The second switch unit includes: a fourth transistor, a second end of the fourth transistor is connected to the first end of the first transistor; The second load comprises: a fourth resistor, a first end of the fourth resistor is connected to the first power line, and a second end of the fourth resistor is connected to the first end of the fourth transistor; The third switch unit includes: a fifth transistor, a second end of the fifth transistor is connected to the first end of the second transistor; The third load comprises: a fifth resistor, a first end of the fifth resistor is connected to the first power line, and a second end of the fifth resistor is connected to the first end of the fifth transistor; The fourth switch unit includes: a sixth triode, a second end of the sixth triode is connected to the first end of the second triode; The fourth load includes: a sixth resistor, a first end of the sixth resistor is connected to the first power line, and a second end of the sixth resistor is connected to the first end of the sixth transistor.

4. The track-and-hold amplifier according to claim 1, characterized in that: The switch emitter follower module comprises: A first signal following unit, connected to the first power line and the input buffer module with switch, and configured to follow the input buffer module with switch to output when turned on; a first switch branch, connected to the first signal following unit, and configured to open the first signal following unit according to the third control signal; a second switch branch, connected to the first signal following unit, and configured to turn off the first signal following unit according to the fourth control signal; a second current source connected between the first switch branch and the second power line; and also connected between the second switch branch and the second power line; The first signal following unit, the first switch branch, the second switch branch and the second current source are symmetrically provided with a second signal following unit, a third switch branch, a fourth switch branch and a third current source respectively.

5. The track-and-hold amplifier according to claim 4, characterized in that: The first signal following unit comprises: a seventh transistor, a first end of the seventh transistor is connected to the first power line, and a control end of the seventh transistor is connected to the input buffer module with switch; The first switch branch includes: an eighth triode and a ninth triode; the first end of the eighth triode is connected to the second end of the seventh triode, the second end of the eighth triode is connected to the first end of the ninth triode; the second end of the ninth triode is connected to the first end of the second current source; the ninth triode is used to be turned on according to the third control signal; The second switch branch includes: a tenth transistor and an eleventh transistor; the first end of the tenth transistor is connected to the control end of the seventh transistor, the second end of the tenth transistor is connected to the first end of the eleventh transistor; the second end of the eleventh transistor is connected to the first end of the second current source; the eleventh transistor is used to be turned on according to the fourth control signal; The second signal follower unit comprises: a twelfth transistor, a first end of the twelfth transistor is connected to the first power line, and a control end of the twelfth transistor is connected to the switch input buffer module; The third switch branch includes: a thirteenth triode and a fourteenth triode; the first end of the thirteenth triode is connected to the second end of the twelfth triode, the second end of the thirteenth triode is connected to the first end of the fourteenth triode; the second end of the fourteenth triode is connected to the first end of the third current source; the fourteenth triode is used to be turned on according to the third control signal; The fourth switch branch includes: a fifteenth transistor and a sixteenth transistor; the first end of the fifteenth transistor is connected to the control end of the twelfth transistor, and the second end of the fifteenth transistor is connected to the first end of the sixteenth transistor; the second end of the sixteenth transistor is connected to the first end of the third current source; the sixteenth transistor is used to be turned on according to the fourth control signal.

6. The track-and-hold amplifier according to claim 5, characterized in that: The switch emitter follower module also includes: a seventeenth triode, wherein a first end of the seventeenth triode is connected to a second end of the tenth triode, and the seventeenth triode is used to be turned on according to a fifth control signal; and a turn-on time of the seventeenth triode is faster than a turn-on time of the eleventh triode; a seventh resistor, wherein a first end of the seventh resistor is connected to a second end of the seventeenth transistor, and a second end of the seventh resistor is connected to a second power line; an eighteenth triode, wherein a first end of the eighteenth triode is connected to a second end of the fifteenth triode, and the eighteenth triode is used to be turned on according to a fifth control signal; and a turn-on time of the eighteenth triode is faster than a turn-on time of the sixteenth triode; An eighth resistor, wherein a first end of the eighth resistor is connected to a second end of the eighteenth transistor, and a second end of the eighth resistor is connected to a second power line.

7. The track-and-hold amplifier according to claim 1, characterized in that: The emitter follower module comprises: a first capacitor, wherein a first end of the first capacitor is connected to a first power line, and a second end of the first capacitor is connected to the switch emitter follower module; the first capacitor is used to follow the output when the switch emitter follower module is turned on, and store the voltage output by the switch emitter follower module; when the switch emitter follower module is turned off, output is performed according to the stored voltage; a nineteenth triode, wherein a first end of the nineteenth triode is connected to the first power line, and a control end of the nineteenth triode is connected to the second end of the first capacitor; a fourth current source, wherein a first end of the fourth current source is connected to a second end of the nineteenth transistor, and a second end of the fourth current source is connected to a second power line; a second capacitor, wherein a first end of the second capacitor is connected to the first power line, and a second end of the second capacitor is connected to the switch emitter follower module; the second capacitor is used to follow the output when the switch emitter follower module is turned on, and store the voltage output by the switch emitter follower module; when the switch emitter follower module is turned off, output according to the stored voltage; A twenty-third transistor, a first end of the second third transistor is connected to the first power line, and a control end of the second third transistor is connected to the second end of the second capacitor; A fifth current source, wherein a first end of the fifth current source is connected to a second end of the second triode, and a second end of the fifth current source is connected to a second power line.

8. The track-and-hold amplifier according to claim 2, characterized in that: The track-and-hold amplifier further comprises: The feedback buffer module is connected between the switch input buffer module and the second power line, and is also connected to the emitter follower module. The feedback buffer module is used to stabilize the signal input from the switch input buffer module to the switch emitter follower module.

9. The track-and-hold amplifier according to claim 8, characterized in that: The feedback buffer module comprises: a twenty-first triode, a first end of the twenty-first triode being connected to the first end of the second load, and the twenty-first triode being configured to be turned on according to the first control signal; a twenty-second triode, a first end of the twenty-second triode being connected to the first end of the first load, and the twenty-second triode being configured to be turned on according to the second control signal; A twenty-third triode, a first end of the twenty-third triode being connected to the second end of the twenty-first triode and the second end of the twenty-second triode respectively; a ninth resistor, a first end of the ninth resistor being connected to the second end of the twenty-third transistor; a twenty-fourth triode, a first end of the twenty-fourth triode being connected to the first end of the fourth load, and the twenty-fourth triode being configured to be turned on according to the first control signal; a twenty-fifth triode, a first end of the twenty-fifth triode being connected to the first end of the third load, and the twenty-fifth triode being configured to be turned on according to the second control signal; A twenty-sixth triode, a first end of the twenty-sixth triode being connected to the second end of the twenty-fourth triode and the second end of the twenty-fifth triode respectively; a tenth resistor, a first end of the tenth resistor being connected to the second end of the twenty-sixth transistor; A sixth current source is connected between the ninth resistor and the second power line, and the sixth current source is also connected between the tenth resistor and the second power line.

10. The track-and-hold amplifier according to claim 5, characterized in that: The tracking and holding amplifier further includes: an anti-leakage module, used to filter out the leakage signal output by the switch emitter follower module; the anti-leakage module includes a first anti-leakage unit and a second anti-leakage unit; The first end of the first anti-leakage unit is connected to the second end of the seventh transistor, and the second end of the first anti-leakage unit is connected to the control end of the twelfth transistor; The first end of the second anti-leakage unit is connected to the second end of the twelfth transistor, and the second end of the second anti-leakage unit is connected to the control end of the seventh transistor; The first anti-leakage unit comprises: a twenty-seventh triode, a twenty-eighth triode, a twenty-ninth triode and a thirty-third triode; the second end of the twenty-seventh triode is connected to the second end of the twenty-eighth triode, the first end of the twenty-eighth triode is connected to the first end of the thirty-third triode, the second end of the thirty-third triode is connected to the second end of the twenty-ninth triode, the first end of the twenty-ninth triode is connected to the first end of the twenty-seventh triode, the control end of the twenty-seventh triode is connected to the control end of the twenty-ninth triode, and the control end of the twenty-eighth triode is connected to the control end of the thirty-third triode; The connection point between the control end of the twenty-seventh transistor and the control end of the twenty-ninth transistor is connected to the second end of the seventh transistor; the connection point between the control end of the twenty-eighth transistor and the control end of the thirty-third transistor is connected to the control end of the twelfth transistor; The second anti-leakage unit comprises: A thirty-first triode, a thirty-second triode, a thirty-third triode and a thirty-fourth triode; the second end of the thirty-first triode is connected to the second end of the thirty-second triode, the first end of the thirty-second triode is connected to the first end of the thirty-fourth triode, the second end of the thirty-fourth triode is connected to the second end of the thirty-third triode, the first end of the thirty-third triode is connected to the first end of the thirty-first triode, the control end of the thirty-first triode is connected to the control end of the thirty-third triode, and the control end of the thirty-second triode is connected to the control end of the thirty-fourth triode; The connection between the control end of the thirty-first transistor and the control end of the thirty-third transistor is connected to the control end of the seventh transistor; the connection between the control end of the thirty-second transistor and the control end of the thirty-fourth transistor is connected to the second end of the twelfth transistor.

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