Offset Calibration Device for Amplifier and Its Calibration Method

Abstract

The present application provides an offset calibration device and a calibration method for an amplifier. The calibration device includes a calibration module and a control module. The calibration module is configured to output a compensation current to the amplifier to cancel the current deviation caused by the offset voltage of the amplifier and eliminate the offset voltage of the amplifier. The calibration module includes a voltage generation unit and a current calibration unit. The voltage generation unit is configured to adjust the voltage through a variable resistor to generate a reference voltage and an adjustment voltage. The current calibration unit is configured to receive the reference voltage and the adjustment voltage, generate a first compensation current and a second compensation current, and output the first compensation current and the second compensation current to the amplifier to cancel the current deviation caused by the offset voltage of the amplifier and eliminate the offset voltage of the amplifier. The control module is configured to configure the amplifier to enter the calibration mode, control the calibration module to calibrate the amplifier, and detect the output voltage of the amplifier in real time to determine whether the calibration is completed.

Description

Technical Field

[0001] This application relates to the field of amplifiers, and specifically to an offset calibration device for an amplifier and its calibration method. Background Art

[0002] An amplifier is a very important module in analog circuits, and the performance indicators of the amplifier will affect the core performance of the analog module. Among the indicators that limit the amplifier, one is the offset voltage, which is usually caused by process manufacturing deviations. To improve the accuracy indicators of analog circuits, the offset voltage of the amplifier needs to be calibrated.

[0003] Currently, the following are several commonly used methods for optimizing the offset voltage of amplifiers.

[0004] The first category is the switched-capacitor chopper amplifier. By using chopper technology, low-frequency noise and offset voltage are modulated to high frequencies and then removed through filtering. The principle is as Figure 1 shown. In the figure, Vin is the input signal, Vout is the output signal, A(f) is the gain of the linear amplifier, M1(t) and M2(t) are square-wave signals for modulating and demodulating the signal, and Vos and VN represent the determined offset voltage and noise. Its working principle is to first modulate the input signal Vin to high frequencies with a square-wave signal M1(t). To avoid signal aliasing, the frequency of the square-wave signal should be more than twice the cut-off frequency ft of the input signal, and the duty cycle of the square-wave signal is 50%. The advantage of this solution is good offset cancellation effect, and the disadvantages are complex timing control, inability to process continuous signals, and the need for a relatively large filtering circuit.

[0005] The second category is to increase the size of the key amplifying transistors of the amplifier. The advantage of this solution is that it can reduce the offset, and the disadvantage is that it requires a larger area consumption. Summary of the Invention

[0006] Based on this, an embodiment of this application provides an offset calibration device for an amplifier, including a calibration module and a control module. The calibration module is used to output a compensation current to the amplifier to offset the current deviation caused by the offset voltage of the amplifier and eliminate the offset voltage of the amplifier. The calibration module includes a voltage generation unit and a current calibration unit. The voltage generation unit is used to adjust the voltage through an adjustable resistor to generate a reference voltage and an adjustment voltage. The current calibration unit is used to receive the reference voltage and the adjustment voltage, generate a first compensation current and a second compensation current, and output the first compensation current and the second compensation current to the amplifier to offset the current deviation caused by the offset voltage of the amplifier and eliminate the offset voltage of the amplifier. The control module is used to configure the amplifier to enter the calibration mode, control the calibration module to calibrate the amplifier, and real-time detect the output voltage of the amplifier to determine whether the calibration is completed.

[0007] According to some embodiments, the first input terminal and the second input terminal of the amplifier are short-circuited and connected to the input terminal of the current calibration unit for receiving the reference voltage.

[0008] According to some embodiments, the current calibration unit includes an auxiliary amplifying transistor.

[0009] According to some embodiments, the auxiliary amplifying transistor is of the same type as the amplifier.

[0010] According to some embodiments, the current calibration unit further includes a first current source, one end of the first current source is connected to the power supply, and the other end is connected to the auxiliary amplifying transistor.

[0011] According to some embodiments, the source electrode of the auxiliary amplifying transistor is connected to the other end of the first current source, the first input terminal of the auxiliary amplifying transistor inputs the reference voltage and the second input terminal of the auxiliary common-source amplifier inputs the adjustment voltage, or the first input terminal of the auxiliary common-source amplifier inputs the adjustment voltage and the second input terminal of the auxiliary amplifying transistor inputs the reference voltage. A first compensation current is generated by the first current source and the reference voltage, and a second compensation current is generated by the first current source and the adjustment voltage.

[0012] According to some embodiments, the voltage generating unit includes a second current source, a variable resistor and a capacitor. One end of the second current source is connected to the power supply; one end of the variable resistor is connected to the other end of the second current source, the other end of the variable resistor is connected to the ground, and the voltage at the adjustable end of the variable resistor is the adjustment voltage; one end of the capacitor is connected to the fixed tap of the variable resistor, and the other end of the capacitor is connected to the ground, and the voltage of the capacitor is the reference voltage.

[0013] According to some embodiments, the first current source or the second current source is an adjustable current source.

[0014] According to some embodiments, the variable resistor is adjusted by the control module.

[0015] According to some embodiments, the adjustable end of the variable resistor includes N adjustable taps, N is a natural number greater than 1, and one end of the variable resistor and the N adjustable taps are connected to the first input terminal or the second input terminal of the auxiliary amplifying transistor through N + 1 adjustment switches.

[0016] According to some embodiments, the auxiliary amplification tube includes a first amplification tube and a second amplification tube. The gate of the first amplification tube serves as the first input terminal of the auxiliary amplification tube; the gate of the second amplification tube serves as the second input terminal of the auxiliary amplification tube; the sources of the first amplification tube and the second amplification tube are connected to the first current source, and the drains of the first amplification tube and the second amplification tube are connected to the amplifier.

[0017] According to some embodiments, the amplifier includes a third amplification tube and a fourth amplification tube. The gate of the third amplification tube serves as the first input terminal of the amplifier; the gate of the fourth amplification tube serves as the second input terminal of the amplifier; the first input terminal of the amplifier is connected to one end of a first switch, the second input terminal of the amplifier is connected to one end of a second switch, the other ends of the first switch and the second switch are short-circuited, the sources of the third amplification tube and the fourth amplification tube are connected to the third current source, the drain of the third amplification tube is connected to the drain of the second amplification tube, and the drain of the fourth amplification tube is connected to the drain of the first amplification tube.

[0018] According to some embodiments, the control module includes a switch control circuit and a voltage detection circuit. The switch control circuit controls the short-circuiting of the first input terminal and the second input terminal of the amplifier, and sequentially controls the opening and closing of N + 1 adjustment switches to adjust the compensation current; the voltage detection circuit continuously detects the output voltage of the amplifier and determines whether calibration is completed based on the output voltage of the amplifier.

[0019] The embodiments of the present application further provide a calibration method for a calibration device of an offset of the amplifier as described above, including: adjusting the compensation current output by the calibration module to the amplifier; continuously detecting the output voltage of the amplifier and determining whether calibration is completed based on the output voltage of the amplifier.

[0020] According to some embodiments, adjusting the compensation current output by the calibration module to the amplifier includes: controlling the short-circuiting of the first input terminal, the second input terminal of the amplifier and the input terminal of the current calibration unit receiving the reference voltage; sequentially controlling the closing of N adjustable switches, adjusting the adjustment voltage by adjusting the value of the adjustable resistor, and thereby adjusting the compensation current until the output voltage jumps.

[0021] The technical solution provided by the embodiments of the present application realizes the offset calibration of the amplifier by adding fewer circuits, consumes less layout area and power consumption, and after calibration, the amplifier can process continuous signals, the circuit is simple, the calibration method is simple, and it is convenient for chip integration. Description of the Drawings

[0022] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other accompanying drawings can also be obtained based on these drawings without exceeding the scope claimed by the present application.

[0023] Figure 1 is a schematic diagram of the composition of an offset calibration device for an amplifier provided by an embodiment of the present application.

[0024] Figure 2 is a structural block diagram of a current calibration unit provided by an embodiment of the present application.

[0025] Figure 3 is a structural block diagram of another current calibration unit provided by an embodiment of the present application.

[0026] Figure 4 is a structural block diagram of a voltage generation unit provided by an embodiment of the present application.

[0027] Figure 5 is a structural block diagram of a control module provided by an embodiment of the present application.

[0028] Figure 6 is a schematic flow chart of a calibration method for an offset calibration device of an amplifier provided by an embodiment of the present application.

[0029] Figure 7 is a timing diagram of an offset calibration device for an amplifier provided by an embodiment of the present application.

[0030] Figure 8 is a timing diagram of another offset calibration device for an amplifier provided by an embodiment of the present application. Detailed implementation manners

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the present application.

[0032] It should be understood that the terms "first", "second", etc. in the claims, the description, and the accompanying drawings of the present application are used to distinguish different objects, rather than to describe a specific order. The terms "including" and "comprising" used in the description and claims of the present application indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0033] Figure 1 It is a schematic diagram of the composition of an offset calibration device for an amplifier provided by an embodiment of the present application, including a calibration module 200 and a control module 300.

[0034] The calibration module 200 is used to output a compensation current to the amplifier 100 to offset the current deviation caused by the offset voltage of the amplifier 100 and eliminate the offset voltage of the amplifier 100. The control module 300 configures the amplifier 100 to enter the calibration mode, controls the calibration module 200 to calibrate the amplifier 100, and real-time detects the output voltage OPA_OUT of the amplifier 100 to determine whether the calibration is completed.

[0035] The calibration module 200 includes a voltage generation unit 201 and a current calibration unit 202.

[0036] The voltage generation unit 201 is used to adjust the voltage through a variable resistor to generate a reference voltage and an adjustment voltage. At this time, the first input terminal and the second input terminal of the amplifier 100 are short-circuited and connected to the input terminal of the current calibration unit 202 that receives the reference voltage. The current calibration unit 202 is used to receive the reference voltage and the adjustment voltage, generate a first compensation current and a second compensation current, and output the first compensation current and the second compensation current to the amplifier 100 to offset the current deviation caused by the offset voltage of the amplifier 100 and eliminate the offset voltage of the amplifier 100.

[0037] Figure 2 It is a structural block diagram of a current calibration unit provided by an embodiment of the present application.

[0038] In Figure 1 Based on the embodiment, the current calibration unit 202 adopts an auxiliary common-source amplifier.

[0039] The first input terminal PM2a of the auxiliary common-source amplifier inputs the reference voltage VCM and the second input terminal PM2b of the auxiliary common-source amplifier 202 inputs the adjustment voltage VCM_trim. By receiving the reference voltage VCM and the adjustment voltage VCM_trim, a first compensation current I1_b and a second compensation current I1_a are generated. The output terminal of the auxiliary common-source amplifier 202 outputs the first compensation current I1_b and the second compensation current I1_a to the amplifier 100 to offset the current deviation caused by the offset voltage of the amplifier 100 and eliminate the offset voltage of the amplifier 100.

[0040] In some other embodiments, the voltage generating unit 201 generates a reference voltage and an adjustment voltage. The first input terminal PM2a of the auxiliary common-source amplifier 202 inputs the adjustment voltage VCM_trim, and the second input terminal PM2b of the auxiliary common-source amplifier 202 inputs the reference voltage VCM. By receiving the reference voltage VCM and the adjustment voltage VCM_trim, a first compensation current I1_b and a second compensation current I1_a are generated. The output terminal of the auxiliary common-source amplifier 202 outputs the first compensation current I1_b and the second compensation current I1_a to the amplifier 100 to offset the current deviation caused by the offset voltage of the amplifier 100 and eliminate the offset voltage of the amplifier 100, as Figure 3 shown.

[0041] The auxiliary common-source amplifier includes a first current source I1 and an auxiliary amplifying transistor PM2. The auxiliary amplifying transistor is of the same type as the amplifier 100.

[0042] One end of the first current source I1 is connected to the power supply. The source electrode of the auxiliary amplifying transistor PM2 is connected to the other end of the first current source I1. The first input terminal PM2a of the auxiliary amplifying transistor PM2 inputs the reference voltage VCM, and the second input terminal PM2b of the auxiliary amplifying transistor PM2 inputs the adjustment voltage VCM_trim. A first compensation current I1_b is generated through the first current source I1 and the reference voltage VCM, and a second compensation current I1_a is generated through the first current source I1 and the adjustment voltage VCM_trim. The output terminal of the auxiliary amplifying transistor PM2 outputs the first compensation current I1_b and the second compensation current I1_a to the amplifier 100 to offset the current deviation caused by the offset voltage of the amplifier 100 and eliminate the offset voltage of the amplifier 100.

[0043] In some other embodiments, as Figure 3 shown, one end of the first current source I1 is connected to the power supply. The source electrode of the auxiliary amplifying transistor PM2 is connected to the other end of the first current source I1. The first input terminal PM2a of the auxiliary amplifying transistor PM2 inputs the adjustment voltage VCM_trim, and the second input terminal PM2b of the auxiliary amplifying transistor PM2 inputs the reference voltage VCM. A first compensation current I1_b is generated through the first current source I1 and the adjustment voltage VCM_trim, and a second compensation current I1_a is generated through the first current source I1 and the reference voltage VCM. The output terminal of the auxiliary amplifying transistor PM2 outputs the first compensation current I1_b and the second compensation current I1_a to the amplifier 100 to offset the current deviation caused by the offset voltage of the amplifier 100 and eliminate the offset voltage of the amplifier 100.

[0044] Both the first current source I1 and the second current source I2 are adjustable current sources.

[0045] The auxiliary amplifying transistor PM2 includes a first amplifying transistor PM2a and a second amplifying transistor PM2b.

[0046] The gate of the first amplifying transistor PM2a serves as the first input terminal of the auxiliary amplifying transistor. The gate of the second amplifying transistor PM2b serves as the second input terminal of the auxiliary amplifying transistor PM2. The sources of the first amplifying transistor PM2a and the second amplifying transistor PM2b are connected to the first current source I1, and the drains of the first amplifying transistor PM2a and the second amplifying transistor PM2b are connected to the amplifier 100.

[0047] The amplifier 100 includes a third amplifying transistor PM1a and a fourth amplifying transistor PM1b.

[0048] The gate of the third amplifying transistor PM1a is connected to the first input terminal of the auxiliary amplifying transistor PM2 through the first switch SW1. The gate of the fourth amplifying transistor PM1b is connected to the first input terminal of the auxiliary amplifying transistor PM2 through the second switch SW2. The first switch SW1 and the second switch SW2 are linked. The sources of the third amplifying transistor PM1a and the fourth amplifying transistor PM1b are connected to the third current source I0. The drain of the third amplifying transistor PM1a is connected to the drain of the second amplifying transistor PM2b, and the drain of the fourth amplifying transistor PM1b is connected to the drain of the first amplifying transistor PM2a. The amplifying transistors PM3, PM4, and NM1 constitute the cascode push-pull output stage of the amplifier 100. PM3 includes amplifying transistors PM3a and PM3b, PM4 includes amplifying transistors PM4a and PM4b, NM1 includes amplifying transistors NM1a and NM1b, and I3 and I4 are two current sources.

[0049] The control module 300 is used to configure the amplifier 100 to enter the calibration mode, control the calibration module 200 to calibrate the amplifier 100, and detect the output voltage OPA_OUT of the amplifier 100 in real time to determine whether the calibration is completed.

[0050] The technical solution provided in this embodiment realizes the offset calibration of the amplifier by adding fewer circuits, consumes less layout area and power consumption, and after calibration, the amplifier can process continuous signals. The circuit is simple and the calibration method is simple, which is convenient for chip integration.

[0051] Figure 4 It is a structural block diagram of a voltage generation unit provided by an embodiment of the present application.

[0052] The voltage generation unit 201 includes a second current source I2, a variable resistor, and a capacitor C1. One end of the second current source I2 is connected to the power supply. One end of the variable resistor is connected to the other end of the second current source I2, the other end of the variable resistor is connected to the ground, and the voltage at the adjustable end is the adjustment voltage VCM_trim. One end of the capacitor C1 is connected to the fixed tap of the variable resistor, and the other end is connected to the ground. The voltage of the capacitor C1 is the reference voltage VCM.

[0053] The control module 300 adjusts the magnitude of the adjustable resistor. The adjustable end of the adjustable resistor includes N adjustable taps, where N is a natural number greater than 1. One end of the adjustable resistor and the N adjustable taps are connected through N + 1 adjustment switches S0 - S N Connect to the second input terminal PM2b of the auxiliary amplifier tube PM2.

[0054] The control module 300 includes a switch control circuit 301 and a voltage detection circuit 302.

[0055] The switch control circuit 301 controls the opening and closing of the first switch SW1 and the second switch SW2, configures the amplifier 100 to enter the calibration mode, and sequentially controls the opening and closing of the N + 1 adjustment switches S0 - S N to adjust the compensation current. The voltage detection circuit 302 continuously detects the output voltage OPA_OUT of the amplifier 100 and determines whether the calibration is completed according to the output voltage OPA_OUT.

[0056] The technical solution provided in this embodiment has a simple calibration circuit that is easy to implement, low power consumption, and after calibration, the amplifier can process continuous signals. The circuit is simple, the calibration method is simple, and it is convenient for chip integration.

[0057] Figure 5 is a structural block diagram of a control module provided in an embodiment of the present application.

[0058] The control module 300 includes a controller and an input circuit. The input circuit is used to input the adjustable switch signals S0 - SN and output the voltage detection signal.

[0059] Figure 6 is a schematic flowchart of a calibration method for an offset calibration device of an amplifier provided in an embodiment of the present application.

[0060] In S110, the control module 300 adjusts the compensation current output from the calibration module 200 to the amplifier 100.

[0061] The enable signal cal_en and the clock signal cal_clock of the control module 300 are at a high level. The first switch SW1 and the second switch SW2 are linked, and the first switch SW1 and the second switch SW2 are controlled to close, short - circuiting the first input terminal and the second input terminal of the differential amplifier tube of the amplifier 100. The control module 300 sequentially controls the closing of the N + 1 adjustable switches S0 - S N or S N - S0 of the voltage generation unit 201, adjusts the adjustment voltage VCM_trim by adjusting the value of the adjustable resistor, and thus adjusts the compensation current until the level of the output voltage OPA_OUT jumps. The specific timing diagram is as shown in Figure 7 、 Figure 8 shown.

[0062] In the voltage generation unit 201, VCM_trim = VCM + A×I2×R_delt.

[0063] Wherein, VCM_trim is the adjusted voltage, VCM is the reference voltage, and A is the coefficient. When VCM_trim is greater than VCM, A is +1. When VCM_trim is less than VCM, A is -1. I2 is the current of the second current source, and R_delt is the sum of the resistances between the output terminal of VCM_trim and the output terminal of VCM.

[0064] Both the amplifier 100 and the auxiliary amplifying transistor 200 include differential pair amplifying transistors. The differential pair amplifying transistor includes two amplifying transistors with the same parameters. The calculation formula for the current difference of the differential pair amplifying transistor is as follows.

[0065]

[0066] Wherein, I delt is the current difference of the differential pair amplifying transistor, Vin1 is the gate input voltage at one end of the differential pair amplifying transistor, Vin2 is the gate input voltage at the other end of the differential pair amplifying transistor, and ISS is the tail current of the differential pair amplifying transistor.

[0067] K = u×C ox ×W / L.

[0068] Wherein, K is the coefficient of the amplifying transistor, u is the channel mobility of the amplifying transistor, C ox is the gate oxide capacitance, W is the channel width of the amplifying transistor, and L is the effective channel length of the amplifying transistor.

[0069] When the input terminal of the amplifier is short-circuited, due to the influence of the offset voltage Vos of the amplifying transistors PM1a / PM1b, an offset current I delt_vos_100 .

[0070]

[0071] Wherein, I delt_vos_100 is the offset current caused by the offset voltage, V os is the offset voltage, I0 is the tail current of the differential amplifying transistor, and K 100 is the coefficient of the amplifying transistor of the amplifier 100.

[0072] By adjusting the adjustment voltage VCM_trim, a voltage difference Vos_cal = VCM_trim - VCM = A × I2 × R_delt is introduced through the auxiliary amplifying transistors PM2a / PM2b, generating a compensation current Ios_cal_200 = I1a - I1b to cancel the Idelt_vos_100 offset current caused by the offset voltage Vos of the amplifying transistors PM1a / PM1b.

[0073]

[0074] Among them, I1 is the current of the first current source, and K 200 is the coefficient of the amplifying transistor of the auxiliary amplifying transistor 200.

[0075] In S120, the control module 300 continuously detects whether the level of the output voltage OPA_OUT of the amplifier 100 jumps. If the level of the output voltage OPA_OUT jumps, it is determined that the calibration is completed.

[0076] In the scheme as Figure 2 shown, the first input terminal PM2a of the auxiliary amplifying transistor inputs the reference voltage VCM, the second input terminal PM2b of the auxiliary amplifying transistor inputs the adjustment voltage VCM_trim, and the control module 300 sequentially controls the closing of the N + 1 adjustable switches S0 - S N of the voltage generating unit 201. The initial level of the output voltage OPA_OUT is low. By adjusting the value of the adjustable resistor to adjust the adjustment voltage VCM_trim, the compensation current is adjusted accordingly. When it is detected that the level of the output voltage OPA_OUT is high, it is determined that the calibration is completed. The timing diagram is as Figure 7 shown.

[0077] In the scheme as Figure 2 shown, the first input terminal PM2a of the auxiliary amplifying transistor inputs the reference voltage VCM, the second input terminal PM2b of the auxiliary amplifying transistor inputs the adjustment voltage VCM_trim, and the control module 300 sequentially controls the closing of the N + 1 adjustable switches S N -S0 of the voltage generating unit 201. The initial level of the output voltage OPA_OUT is high. By adjusting the value of the adjustable resistor to adjust the adjustment voltage VCM_trim, the compensation current is adjusted accordingly. When it is detected that the level of the output voltage OPA_OUT is low, it is determined that the calibration is completed. The timing diagram is as Figure 8 shown.

[0078] In the scheme as Figure 3In the shown solution, the first input terminal PM2a of the auxiliary amplifier tube inputs the adjustment voltage VCM_trim, and the second input terminal PM2b of the auxiliary amplifier tube inputs the reference voltage VCM. The control module 300 sequentially controls the closing of N + 1 adjustable switches S0 - S N , the initial level of the output voltage OPA_OUT is high. By adjusting the value of the adjustable resistor, the adjustment voltage VCM_trim is adjusted, and accordingly the compensation current is adjusted. When it is detected that the level of the output voltage OPA_OUT is low, it is determined that the calibration is completed. The timing diagram is as Figure 8 shown.

[0079] In the solution as Figure 3 shown, the first input terminal PM2a of the auxiliary amplifier tube inputs the adjustment voltage VCM_trim, and the second input terminal PM2b of the auxiliary amplifier tube inputs the reference voltage VCM. The control module 300 sequentially controls the closing of N + 1 adjustable switches S N -S0, the initial level of the output voltage OPA_OUT is low. By adjusting the value of the adjustable resistor, the adjustment voltage VCM_trim is adjusted, and accordingly the compensation current is adjusted. When it is detected that the level of the output voltage OPA_OUT is high, it is determined that the calibration is completed. The timing diagram is as Figure 7 shown.

[0080] The amplifier tubes PM3, PM4, and NM1 form the cascode push - pull output stage of the amplifier 100. PM3 includes amplifier tubes PM3a and PM3b, PM4 includes amplifier tubes PM4a and PM4b, NM1 includes amplifier tubes NM1a and NM1b, and I3 and I4 are two current sources.

[0081] The technical solution provided in this embodiment, based on the above - mentioned embodiment, realizes the offset calibration of the amplifier through a simple calibration method. After calibration, the amplifier can process continuous signals.

[0082] The above has introduced the embodiments of the present application in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application. At the same time, those skilled in the art, based on the idea of the present application, the changes or deformations made in the specific implementation manner and application scope of the present application all belong to the protection scope of the present application. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. An offset calibration device for an amplifier, comprising: A calibration module for outputting a compensation current to the amplifier to cancel the current deviation caused by the offset voltage of the amplifier and eliminate the offset voltage of the amplifier; The calibration module includes: A voltage generation unit for adjusting the voltage through a variable resistor to generate a reference voltage and an adjustment voltage; A current calibration unit for receiving the reference voltage and the adjustment voltage, generating a first compensation current and a second compensation current, and outputting the first compensation current and the second compensation current to the amplifier to cancel the current deviation caused by the offset voltage of the amplifier and eliminate the offset voltage of the amplifier; A control module for configuring the amplifier to enter the calibration mode, controlling the calibration module to calibrate the amplifier, and detecting the output voltage of the amplifier in real time to determine whether the calibration is completed; The current calibration unit includes an auxiliary amplification tube; The voltage generation unit includes: A second current source, one end connected to the power supply; A variable resistor, one end of the variable resistor is connected to the other end of the second current source, the other end of the variable resistor is connected to the ground, the voltage at the adjustable end of the variable resistor is the adjustment voltage, the adjustable end of the variable resistor includes N adjustable taps, N is a natural number greater than 1, and one end of the variable resistor and the N adjustable taps are connected to the first input pole or the second input pole of the auxiliary amplification tube through N + 1 adjustment switches; A capacitor, one end connected to the fixed tap of the variable resistor, the other end connected to the ground, and the voltage of the capacitor is the reference voltage.

2. The offset calibration device of the amplifier according to claim 1, wherein, The first input pole and the second input pole of the amplifier are short-circuited and connected to the input terminal of the current calibration unit for receiving the reference voltage.

3. The offset calibration device of the amplifier according to claim 1, wherein, The auxiliary amplification tube is of the same type as the amplifier.

4. The offset calibration device for the amplifier according to claim 1 or 3, wherein, The current calibration unit further includes: A first current source, one end connected to the power supply, and the other end connected to the auxiliary amplification tube.

5. The offset calibration device of the amplifier according to claim 4, wherein, The source pole of the auxiliary amplification tube is connected to the other end of the first current source. The reference voltage is input to the first input pole of the auxiliary amplification tube and the adjustment voltage is input to the second input pole of the auxiliary amplification tube, or the adjustment voltage is input to the first input pole of the auxiliary amplification tube and the reference voltage is input to the second input pole of the auxiliary amplification tube. A first compensation current is generated through the first current source and the reference voltage, and a second compensation current is generated through the first current source and the adjustment voltage.

6. The offset calibration device of the amplifier according to claim 5, wherein, The first current source or the second current source is an adjustable current source.

7. The offset calibration device of the amplifier according to claim 5, wherein, The variable resistor is adjusted by the control module.

8. The offset calibration device of the amplifier according to claim 4, wherein, The auxiliary amplification tube includes: A first amplification tube, the gate being the first input pole of the auxiliary amplification tube; A second amplification tube, the gate being the second input pole of the auxiliary amplification tube; The source poles of the first amplification tube and the second amplification tube are connected to the first current source, and the drain poles of the first amplification tube and the second amplification tube are connected to the amplifier.

9. The offset calibration device of the amplifier according to claim 8, wherein, The amplifier includes: A third amplification tube, the gate being the first input pole of the amplifier; A fourth amplification tube, the gate being the second input pole of the amplifier; The first input electrode of the amplifier is connected to one end of the first switch, the second input electrode of the amplifier is connected to one end of the second switch, the other end of the first switch and the other end of the second switch are short-circuited, the source electrodes of the third amplifier tube and the fourth amplifier tube are connected to a third current source, the drain electrode of the third amplifier tube is connected to the drain electrode of the second amplifier tube, and the drain electrode of the fourth amplifier tube is connected to the drain electrode of the first amplifier tube.

10. The offset calibration device of the amplifier according to claim 9, wherein, The control module comprises: A switch control circuit controls the first input terminal and the second input terminal of the amplifier to be short-circuited, and sequentially controls the opening and closing of N+1 regulating switches to regulate the compensation current; The voltage detection circuit detects the output voltage of the amplifier in real time and determines whether the calibration is completed based on the output voltage of the amplifier.

11. A calibration method for the offset calibration device of an amplifier according to any one of claims 1 to 10, comprising: adjusting the compensation current output by the calibration module to the amplifier; The output voltage of the amplifier is detected in real time, and whether the calibration is completed is determined based on the output voltage of the amplifier.

12. The calibration method according to claim 11, wherein adjusting the compensation current output by the calibration module to the amplifier comprises: Controlling to short-connect the first input terminal, the second input terminal of the amplifier and the input terminal of the current calibration unit receiving the reference voltage; The N adjustable switches are controlled to close in sequence, and the adjustment voltage is adjusted by adjusting the value of the adjustable resistor, and the compensation current is adjusted accordingly, until the output voltage jumps.

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