Low-temperature-drift secondary amplification circuit

Abstract

The utility model discloses a low-temperature-drift two-stage amplification circuit which comprises a first-stage amplification circuit module, a second-stage amplification circuit module and a summing circuit module. The output end of the primary amplification circuit module is electrically connected with the input end of the secondary amplification circuit module, and the output end of the secondary amplification circuit module is electrically connected with the input end of the summing circuit module; the primary amplification circuit module is used for primarily amplifying an input signal, outputting a first signal and transmitting the first signal to the secondary amplification circuit module; the secondary amplification circuit module further amplifies the received first signal, outputs a second signal and transmits the second signal to the summing circuit module; and the summing circuit module adds a reference voltage to the received second signal, modulates a final output zero voltage and outputs a final output signal. Therefore, perfect combination of high magnification and low temperature drift is realized.

Description

Technical Field

[0001] This utility model relates to the field of airborne aviation product technology, and in particular to a low-temperature drift two-stage amplifier circuit. Background Technology

[0002] In airborne aviation products, sensor signals typically require amplification to meet the demands of subsequent circuitry. Because sensor signals often exhibit low amplitude and high overload characteristics, amplifier circuits are required to have amplification capabilities as high as 1500 to 2000 times. However, traditional amplifier circuits, at such high amplification levels, are prone to excessive temperature drift in the output signal due to the temperature drift characteristics of the operational amplifier chip's input / output offset voltage, failing to meet operational requirements. Therefore, developing an amplifier circuit that can achieve high amplification while effectively controlling temperature drift is of paramount importance. Summary of the Invention

[0003] This application provides a low-temperature drift two-stage amplifier circuit, proposing a two-stage amplifier circuit design based on a combination of domestically produced instrumentation operational amplifiers and ordinary precision operational amplifiers, achieving a perfect combination of high amplification and low temperature drift.

[0004] This application provides a low-temperature drift two-stage amplifier circuit, including a first-stage amplifier circuit module, a second-stage amplifier circuit module, and an adder circuit module; the output terminal of the first-stage amplifier circuit module is electrically connected to the input terminal of the second-stage amplifier circuit module, and the output terminal of the second-stage amplifier circuit module is electrically connected to the input terminal of the adder circuit module.

[0005] The first-stage amplifier circuit module amplifies the input signal initially and outputs the first signal, which is then transmitted to the second-stage amplifier circuit module.

[0006] The second-stage amplifier circuit module further amplifies the received first signal and outputs a second signal, which is then transmitted to the adder circuit module.

[0007] The adder circuit module applies a reference voltage to the received second signal, modulates the zero-position voltage of the final output, and outputs the final output signal.

[0008] Preferably, the first-stage amplifier circuit module includes: a first instrumentation operational amplifier, a first transient voltage suppression diode, a second transient voltage suppression diode, a second potentiometer, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a sixth capacitor, a seventh capacitor, a ninth capacitor, a first resistor, a fourth resistor, a tenth resistor, a thirteenth resistor, a fourteenth resistor, and a fifteenth resistor;

[0009] The secondary amplifier circuit module includes: a first general-purpose precision operational amplifier, a first potentiometer, a fifth capacitor, an eighth capacitor, a fifth resistor, an eleventh resistor, and a twelfth resistor;

[0010] The adder circuit module includes: a second general-purpose precision operational amplifier, a second resistor, a third resistor, a sixth resistor, a seventh resistor, and an eighth resistor.

[0011] Preferably, pin 1 of the first instrumentation operational amplifier is connected to pin 8 via the fifteenth resistor to form a feedback loop; pin 2 of the first instrumentation operational amplifier is connected to one end of the tenth resistor, one end of the sixth capacitor, and one end of the seventh capacitor, while the other end of the tenth resistor is connected to the negative input signal terminal S1-; pin 3 of the first instrumentation operational amplifier is connected to one end of the thirteenth resistor, one end of the ninth capacitor, and the other end of the seventh capacitor, while the other end of the thirteenth resistor is connected to the positive input signal terminal S1+; pin 4 of the first instrumentation operational amplifier is connected to one end of the first capacitor and one end of the fourth capacitor via the first resistor, while the other end of the first resistor is connected to the input -12V DC power supply; pin 5 of the first instrumentation operational amplifier is directly connected to power ground GND; pin 6 of the first instrumentation operational amplifier is connected to one end of the twelfth resistor, and the other end of the twelfth resistor is connected to the input terminal of the secondary amplifier circuit module; pin 7 of the first instrumentation operational amplifier is connected to one end of the second capacitor and one end of the third capacitor via the fourth resistor, the other ends of the second capacitor and the third capacitor are connected to power ground GND, and the other end of the fourth resistor is connected to the input +12V DC power supply; pin 8 of the first instrumentation operational amplifier is connected to pin 1 via the fifteenth resistor.

[0012] Preferably, one end of the first transient voltage suppression diode is connected to the negative terminal S1- of the input signal, and the other end is connected to the power ground GND, in order to protect the circuit from the influence of negative transient voltage;

[0013] One end of the second transient voltage suppression diode is connected to the positive terminal S1+ of the input signal, and the other end is connected to the power supply ground GND, in order to protect the circuit from the influence of positive transient voltage.

[0014] Pin 1 of the second potentiometer is connected to the negative terminal S1- of the input signal, pin 2 is connected to the positive terminal S1+ of the input signal, and pin 3 is connected to the power ground GND through the fourteenth resistor. This is used to adjust the attenuation or gain of the input signal.

[0015] The first, second, third, and fourth capacitors serve as filter capacitors, with their other ends connected to the power supply ground (GND) to filter out high-frequency noise in the power supply or signal.

[0016] The sixth and ninth capacitors are decoupling capacitors, connected between pins 2 and 3 of the first instrumentation operational amplifier and the power ground GND, respectively, to reduce the impact of power fluctuations on amplifier performance.

[0017] The seventh capacitor is connected across pins 2 and 3 of the first instrumentation operational amplifier as a coupling capacitor for the differential input terminal.

[0018] The first and fourth resistors are used as current-limiting resistors and are connected between the first, fourth, second, and third capacitors and their corresponding DC power supplies, respectively.

[0019] The tenth and thirteenth resistors are used as output resistors and are connected between pins 2 and 3 of the first instrumentation operational amplifier and the input signal terminals S1- and S1+, respectively.

[0020] The fourteenth resistor works in conjunction with the second potentiometer to adjust the bias of the input signal;

[0021] The fifteenth resistor serves as a feedback resistor, connected between pins 1 and 8 of the first instrument's operational amplifier to set the amplifier's gain.

[0022] Preferably, pin 1 of the first general-purpose precision operational amplifier is connected to pin 5 of the second general-purpose precision operational amplifier through a sixth resistor to form feedback at the non-inverting input terminal; pin 2 of the first general-purpose precision operational amplifier is connected to one end of the eleventh resistor and one end of the fifth resistor, the other end of the eleventh resistor is connected to the power ground GND, and the other end of the fifth resistor is connected to pin 1 of the first potentiometer; pin 3 of the first general-purpose precision operational amplifier is connected to one end of the twelfth resistor, and the other end of the twelfth resistor is connected to pin 6 of the first instrumentation operational amplifier; pin 4 of the first general-purpose precision operational amplifier is connected to the input -12V DC power supply; and pin 8 of the first general-purpose precision operational amplifier is connected to the input +12V DC power supply.

[0023] Preferably, pin 1 of the first potentiometer is connected to the fifth resistor, and pins 2 and 3 of the first potentiometer are connected in parallel to pin 1 of the first general-purpose precision operational amplifier for adjusting the gain or bias of the amplifier.

[0024] The fifth and eighth capacitors serve as filter capacitors for the positive and negative power supplies, respectively, and their other ends are connected to the power supply ground (GND).

[0025] The fifth and eleventh resistors serve as bias and current-limiting resistors at the input terminals;

[0026] The twelfth resistor serves as the signal transmission resistor connecting the first-stage amplifier module and the second-stage amplifier module.

[0027] Preferably, pin 6 of the second general-purpose precision operational amplifier is connected to the power ground GND through a second resistor to form the bias of the inverting input terminal; pin 7 of the second general-purpose precision operational amplifier is connected to the node between pins 6 and 7 of the second general-purpose precision operational amplifier through a third resistor to realize the addition operation of the signal; pin 5 of the second general-purpose precision operational amplifier is connected to one end of an eighth resistor, and the other end of the eighth resistor is connected to the input reference voltage; pin 5 of the second general-purpose precision operational amplifier is also connected to pin 1 of the first general-purpose precision operational amplifier through a sixth resistor to form the feedback of the non-inverting input terminal; pin 7 of the second general-purpose precision operational amplifier serves as the output terminal and is directly connected to one end of a seventh resistor, and the other end of the seventh resistor is used to output the final output signal.

[0028] Preferably, the second resistor and the third resistor constitute the bias and feedback network of the inverting input terminal; the sixth resistor serves as the feedback resistor of the non-inverting input terminal; the seventh resistor serves as the output resistor; and the eighth resistor is used to limit the input of the reference voltage.

[0029] Preferably, the first-stage amplifier circuit module is specifically used for:

[0030] The input signal is protected by the first transient voltage suppression diode and the second transient voltage suppression diode before being connected to the input terminal of the first instrumentation operational amplifier;

[0031] The first capacitor, the second capacitor, the third capacitor, the fourth capacitor, and the first resistor and the fourth resistor form a power supply filter network to ensure power supply stability.

[0032] The sixth, seventh, and ninth capacitors, together with the tenth, thirteenth, and fifteenth resistors, achieve signal filtering and amplification.

[0033] The second potentiometer is used to adjust the zero position of the input signal.

[0034] Preferably, the secondary amplifier circuit module is specifically used for:

[0035] The received first signal is connected to the input terminal of the first general-purpose precision operational amplifier through the twelfth resistor;

[0036] The fifth and eighth capacitors, along with the fifth and eleventh resistors, constitute a power supply filter network.

[0037] The first potentiometer is used to adjust the amplification factor;

[0038] The addition circuit module is specifically used for:

[0039] The received second signal and the set reference voltage are input to the second general-purpose precision operational amplifier through the sixth resistor and the eighth resistor;

[0040] The second, third, and seventh resistors form a feedback network to achieve precise signal adjustment.

[0041] The final output signal is led out through the seventh resistor.

[0042] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0043] Through a two-stage amplification design, when the sensor signal is input, it first undergoes RC filtering, then is amplified approximately 412 times by the first instrumentation operational amplifier U2, and then amplified 4-5 times by the first general-purpose precision operational amplifier U1A, for a total amplification of 1648-2060 times. Simultaneously, a reference voltage is applied to the second general-purpose precision operational amplifier U1B to modulate the final output zero-point voltage. This achieves a high amplification factor of 1500-2000 times, meeting the signal amplification requirements of airborne sensors. High-performance domestic components are selected, and through meticulous circuit design, the impact of temperature on the amplification factor and output signal is effectively reduced, ensuring stable operation of the circuit over a wide temperature range. The reference voltage design in the second potentiometer W2 and the adder circuit module 30 enables zero-point adjustable output signal functionality, improving the circuit's flexibility and adaptability. The addition of a transient voltage suppression diode effectively protects the circuit from transient overvoltage damage, improving circuit reliability. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the low-temperature drift two-stage amplifier circuit according to an embodiment of the present invention;

[0045] Figure 2 This is a circuit diagram of a low-temperature drift two-stage amplifier circuit according to an embodiment of the present invention;

[0046] In the diagram: 100 - Low-temperature drift second-stage amplifier circuit; 10 - First-stage amplifier circuit module; 20 - Second-stage amplifier circuit module; 30 - Adder circuit module; U2 - First instrumentation operational amplifier; U1A - First general-purpose precision operational amplifier; U1B - Second general-purpose precision operational amplifier; D1 - First transient voltage suppressor diode; D2 - Second transient voltage suppressor diode; W1 - First potentiometer; W2 - Second potentiometer; C1 - First capacitor; C2 - Second capacitor; C3 - Third capacitor; C 4 - Fourth capacitor; C5 - Fifth capacitor; C6 - Sixth capacitor; C7 - Seventh capacitor; C8 - Eighth capacitor; C9 - Ninth capacitor; R1 - First resistor; R2 - Second resistor; R3 - Third resistor; R4 - Fourth resistor; R5 - Fifth resistor; R6 - Sixth resistor; R7 - Seventh resistor; R8 - Eighth resistor; R10 - Tenth resistor; R11 - Eleventh resistor; R12 - Twelfth resistor; R13 - Thirteenth resistor; R14 - Fourteenth resistor; R15 - Fifteenth resistor. Detailed Implementation

[0047] To facilitate understanding of this utility model, a more comprehensive description of this application will be given below with reference to the accompanying drawings.

[0048] Figure 1 This is a schematic diagram of the low-temperature drift two-stage amplifier circuit according to an embodiment of the present invention.

[0049] like Figure 1 As shown, the low-temperature drift two-stage amplifier circuit 100 includes: a first-stage amplifier circuit module 10, a second-stage amplifier circuit module 20, and an adder circuit module 30.

[0050] Specifically, the output terminal of the first-stage amplifier module 10 is electrically connected to the input terminal of the second-stage amplifier module 20; the output terminal of the second-stage amplifier module 20 is electrically connected to the input terminal of the adder module 30.

[0051] Figure 2 This is a circuit diagram of a low-temperature drift two-stage amplifier circuit according to an embodiment of the present invention.

[0052] like Figure 2 As shown, the low-temperature drift two-stage amplifier circuit 100 includes a first-stage amplifier circuit module 10, a second-stage amplifier circuit module 20, and an adder circuit module 30.

[0053] In some embodiments, the first-stage amplifier circuit module 10 includes: a first instrumentation operational amplifier U2, a first transient voltage suppression diode D1, a second transient voltage suppression diode D2, a second potentiometer W2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a sixth capacitor C6, a seventh capacitor C7, a ninth capacitor C9, a first resistor R1, a fourth resistor R4, a tenth resistor R10, a thirteenth resistor R13, a fourteenth resistor R14, and a fifteenth resistor R15;

[0054] Specifically, the first-stage amplifier circuit module 10 performs preliminary amplification of the input signal, with an amplification factor of approximately 412 times, and outputs the first signal. After being protected by the first transient voltage suppression diode D1 and the second transient voltage suppression diode D2, the input signal is connected to the input terminal of the first instrumentation operational amplifier U2. The first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, and the first resistor R1 and the fourth resistor R4 form a power supply filter network to ensure power supply stability. The sixth capacitor C6, the seventh capacitor C7, the ninth capacitor C9, and the tenth resistor R10, the thirteenth resistor R13, and the fifteenth resistor R15 work together to achieve signal filtering and amplification. The second potentiometer W2 is used to adjust the zero position of the input signal.

[0055] In this configuration, pin 1 of the first instrumentation operational amplifier U2 is connected to pin 8 via the fifteenth resistor R15, forming a feedback loop; pin 2 of the first instrumentation operational amplifier U2 is connected to the tenth resistor R10, one end of the sixth capacitor C6, and one end of the seventh capacitor C7, with the other end of the tenth resistor R10 connected to the negative input signal terminal S1-; pin 3 of the first instrumentation operational amplifier U2 is connected to the thirteenth resistor R13, one end of the ninth capacitor C9, and the other end of the seventh capacitor C7, with the other end of the thirteenth resistor R13 connected to the positive input signal terminal S1+; pin 4 of the first instrumentation operational amplifier U2 is connected to one end of the first capacitor C1 and the fourth capacitor C4 via the first resistor R1, while... The other end of the first resistor R1 is connected to the input -12V DC power supply; pin 5 of the first instrumentation operational amplifier U2 is directly connected to power ground GND; pin 6 of the first instrumentation operational amplifier U2 is connected to one end of the twelfth resistor R12, and the other end of the twelfth resistor R12 is connected to the input terminal of the second-stage amplifier module 20; pin 7 of the first instrumentation operational amplifier U2 is connected to one end of the second capacitor C2 and the third capacitor C3 through the fourth resistor R4, and the other end of the second capacitor C2 and the third capacitor C3 is connected to power ground GND; the other end of the fourth resistor R4 is connected to the input +12V DC power supply; pin 8 of the first instrumentation operational amplifier U2 is connected to pin 1 through the fifteenth resistor R15;

[0056] One end of the first transient voltage suppression diode D1 is connected to the negative input signal terminal S1-, and the other end is connected to the power supply ground GND, in order to protect the circuit from the influence of negative transient voltage;

[0057] One end of the second transient voltage suppression diode D2 is connected to the positive terminal S1+ of the input signal, and the other end is connected to the power supply ground GND, in order to protect the circuit from the influence of positive transient voltage.

[0058] Pin 1 of the second potentiometer W2 is connected to the negative input signal terminal S1-, pin 2 is connected to the positive input signal terminal S1+, and pin 3 is connected to the power supply ground GND through the fourteenth resistor R14. It is used to adjust the attenuation or gain of the input signal.

[0059] The first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 are used as filter capacitors, and their other ends are connected to the power supply ground GND to filter out high-frequency noise in the power supply or signal.

[0060] The sixth capacitor C6 and the ninth capacitor C9 are decoupling capacitors, connected between pins 2 and 3 of the first instrumentation operational amplifier U2 and the power ground GND, respectively, to reduce the impact of power fluctuations on amplifier performance.

[0061] The seventh capacitor C7 is connected across pins 2 and 3 of the first instrumentation operational amplifier U2 as a coupling capacitor for the differential input terminal;

[0062] The first resistor R1 and the fourth resistor R4 are used as current-limiting resistors and are connected between the first capacitor C1, the fourth capacitor C4, the second capacitor C2, the third capacitor C3 and the corresponding DC power supply, respectively.

[0063] The tenth resistor R10 and the thirteenth resistor R13 are used as output resistors and are connected between pins 2 and 3 of the first instrumentation operational amplifier U2 and the input signal terminals S1- and S1+, respectively.

[0064] The fourteenth resistor R14 works in conjunction with the second potentiometer W2 to adjust the bias of the input signal;

[0065] The fifteenth resistor, R15, serves as a feedback resistor and is connected between pins 1 and 8 of the first instrumentation operational amplifier U2 to set the amplifier's gain.

[0066] In some embodiments, the output terminal of the first-stage amplifier module 10 is connected to the input terminal of the second-stage amplifier module 20 through the twelfth resistor R12. The second-stage amplifier module 20 includes: a first general-purpose precision operational amplifier U1A, a first potentiometer W1, a fifth capacitor C5, an eighth capacitor C8, a fifth resistor R5, an eleventh resistor R11, and a twelfth resistor R12.

[0067] Specifically, the second-stage amplifier module 20 further amplifies the first signal after it has been amplified by the first-stage amplifier module 10, with an amplification factor of approximately 4-5 times, and outputs the second signal; the output signal of the first-stage amplifier module 10 is connected to the input terminal of the first general-purpose precision operational amplifier U1A through the twelfth resistor R12; the fifth capacitor C5, the eighth capacitor C8, the fifth resistor R5, and the eleventh resistor R11 constitute a power supply filter network; the first potentiometer W1 is used to adjust the amplification factor;

[0068] Specifically, pin 1 of the first general-purpose precision operational amplifier U1A is connected to pin 5 of the second general-purpose precision operational amplifier U1B via resistor R6, forming feedback at the non-inverting input. Pin 2 of the first general-purpose precision operational amplifier U1A is connected to one end of resistor R11 and resistor R5, respectively. The other end of resistor R11 is connected to power ground GND, and the other end of resistor R5 is connected to pin 1 of the first potentiometer W1. Pin 3 of the first general-purpose precision operational amplifier U1A is connected to one end of resistor R12, and the other end of resistor R12 is connected to pin 6 of the first instrumentation operational amplifier U2. Pin 4 of the first general-purpose precision operational amplifier U1A is connected to the input -12V DC power supply. Pin 8 of the first general-purpose precision operational amplifier U1A is connected to the input +12V DC power supply.

[0069] Pin 1 of the first potentiometer W1 is connected to the fifth resistor R5. Pins 2 and 3 of the first potentiometer W1 are connected in parallel to pin 1 of the first general-purpose precision operational amplifier U1A, which is used to adjust the gain or bias of the amplifier.

[0070] The fifth capacitor C5 and the eighth capacitor C8 serve as filter capacitors for the positive and negative power supplies, respectively, and their other ends are connected to the power supply ground GND.

[0071] The fifth resistor R5 and the eleventh resistor R11 serve as bias and current-limiting resistors at the input terminals;

[0072] The twelfth resistor, R12, serves as the signal transmission resistor connecting the first-stage amplifier module 10 and the second-stage amplifier module 20.

[0073] In some embodiments, the output of the secondary amplifier circuit module 20 is directly transmitted to the input of the adder circuit module 30 through an internal connection. The adder circuit module 30 includes: a second general-purpose precision operational amplifier U1B, a second resistor R2, a third resistor R3, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8.

[0074] Specifically, the adder circuit module 30 modulates the final output zero-point voltage by applying a reference voltage; the second signal output by the second amplifier circuit module 20 and the reference voltage are input to the second general precision operational amplifier U1B through the sixth resistor R6 and the eighth resistor R8; the second resistor R2, the third resistor R3, and the seventh resistor R7 form a feedback network to achieve precise signal adjustment; the final output signal is led out through the seventh resistor R7.

[0075] In this configuration, pin 6 of the second general-purpose precision operational amplifier U1B is connected to the power ground GND via the second resistor R2, forming the bias of the inverting input terminal. Pin 7 of the second general-purpose precision operational amplifier U1B is connected to the node between pins 6 and 7 via the third resistor R3, realizing the signal addition operation. Pin 5 of the second general-purpose precision operational amplifier U1B is connected to one end of the eighth resistor R8, and the other end of the eighth resistor R8 is connected to the input reference voltage. Pin 5 of the second general-purpose precision operational amplifier U1B is also connected to pin 1 of the first general-purpose precision operational amplifier U1A via the sixth resistor R6, forming the feedback of the non-inverting input terminal. Pin 7 of the second general-purpose precision operational amplifier U1B serves as the output terminal, directly connected to one end of the seventh resistor R7, and the other end of the seventh resistor R7 is used for output signal acquisition (the signal after addition).

[0076] The second resistor R2 and the third resistor R3 constitute the bias and feedback network of the inverting input terminal;

[0077] The sixth resistor, R6, serves as the feedback resistor for the non-inverting input terminal.

[0078] The seventh resistor, R7, serves as the output resistor and is connected to subsequent circuitry or signal acquisition points.

[0079] The eighth resistor, R8, is used to set the input of the reference voltage.

[0080] As an example, the specific parameters of the low-temperature drift two-stage amplifier circuit 100 in this embodiment of the present invention are set as follows:

[0081] The first general-purpose precision operational amplifiers U1A and UI8 are of model F2284Z, the first instrumentation operational amplifier U2 is of model FX620GF(Z), the first potentiometer W1 is of model 3296KW-2K-K, the second potentiometer W2 is of model 3296KW-10K-K, and the first transient voltage suppression diode D1 and the second transient voltage suppression diode D2 are of model SMCJ16CA.

[0082] The first resistor R1 and the fourth resistor R4 are RMK2012MB2R0FM models; the second resistor R2, the third resistor R3, and the fifth resistor R5 are RMK2012YB202BM models; the sixth resistor R6, the eighth resistor R8, the eleventh resistor R11, and the twelfth resistor R12 are RMK2012YB102BM models; the seventh resistor R7 is RMK2012YB102BM model; the tenth resistor R10 and the thirteenth resistor R13 are RMK2012KB101FM models; the fourteenth resistor R14 is RMK2012EB334BM model; and the fifteenth resistor R15 is RMK1608YB121FP model.

[0083] The first capacitor C1, the third capacitor C3, the fifth capacitor C5, the sixth capacitor C6, the eighth capacitor C8, and the ninth capacitor C9 are all of model CT41G-0805-X7R-50V-0.1uF-K(N). The second capacitor C2 and the fourth capacitor C4 are of model (G)CT41G-1206-X5R-50V-10uF-M(N). The seventh capacitor C7 is of model (G)CT41G-0805-X7R-50V-1uF-K(N).

[0084] Therefore, through a two-stage amplification design, when the sensor signal is input, it first undergoes RC filtering, and is amplified approximately 412 times by the first instrumentation operational amplifier U2, and then amplified 4-5 times by the first general-purpose precision operational amplifier U1A, for a total amplification of 1648-2060 times. Simultaneously, a reference voltage is applied to the second general-purpose precision operational amplifier U1B to modulate the final output zero-point voltage. This achieves a high amplification factor of 1500-2000 times, meeting the signal amplification requirements of airborne sensors. The use of domestically produced high-performance components and meticulous circuit design effectively reduces the impact of temperature on the amplification factor and output signal, ensuring stable operation over a wide temperature range. The reference voltage design in the second potentiometer W2 and the adder circuit module 30 enables zero-point adjustable output signal functionality, improving the circuit's flexibility and adaptability. The addition of a transient voltage suppression diode effectively protects the circuit from transient overvoltage damage, improving its reliability.

[0085] In summary, the low-temperature drift two-stage amplifier circuit based on domestically produced components provided in this embodiment mainly consists of an instrumentation operational amplifier, a general-purpose precision operational amplifier, a wire-wound potentiometer, a transient voltage suppression diode, resistors, and capacitors. The two-stage amplifier circuit, composed of the instrumentation operational amplifier and the general-purpose precision operational amplifier, can achieve amplification of 1500–2000 times. The first potentiometer allows for adjustment of the amplification factor, the second potentiometer allows for adjustment of the sensor zero point, the transient voltage suppression diode is used for chip circuit protection, and the resistors and capacitors are used for signal filtering. It not only achieves the performance requirements of high amplification factor and low temperature drift but also has additional functions such as zero-point adjustment and circuit protection, providing a stable and reliable signal amplification solution for airborne aviation products.

Claims

1. A low-temperature drift two-stage amplifier circuit, characterized in that, It includes a first-stage amplifier module, a second-stage amplifier module, and an adder module; the output terminal of the first-stage amplifier module is electrically connected to the input terminal of the second-stage amplifier module, and the output terminal of the second-stage amplifier module is electrically connected to the input terminal of the adder module. The first-stage amplifier circuit module amplifies the input signal initially and outputs the first signal, which is then transmitted to the second-stage amplifier circuit module. The second-stage amplifier circuit module further amplifies the received first signal and outputs a second signal, which is then transmitted to the adder circuit module. The adder circuit module applies a reference voltage to the received second signal, modulates the zero-position voltage of the final output, and outputs the final output signal.

2. The low-temperature drift two-stage amplifier circuit as described in claim 1, characterized in that, The first-stage amplifier circuit module includes: a first instrumentation operational amplifier, a first transient voltage suppression diode, a second transient voltage suppression diode, a second potentiometer, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a sixth capacitor, a seventh capacitor, a ninth capacitor, a first resistor, a fourth resistor, a tenth resistor, a thirteenth resistor, a fourteenth resistor, and a fifteenth resistor; The secondary amplifier circuit module includes: a first general-purpose precision operational amplifier, a first potentiometer, a fifth capacitor, an eighth capacitor, a fifth resistor, an eleventh resistor, and a twelfth resistor; The adder circuit module includes: a second general-purpose precision operational amplifier, a second resistor, a third resistor, a sixth resistor, a seventh resistor, and an eighth resistor.

3. The low-temperature drift two-stage amplifier circuit as described in claim 2, characterized in that, Pin 1 of the first instrumentation operational amplifier is connected to pin 8 through the fifteenth resistor to form a feedback loop; pin 2 of the first instrumentation operational amplifier is connected to the tenth resistor, one end of the sixth capacitor and one end of the seventh capacitor respectively, while the other end of the tenth resistor is connected to the negative terminal S1- of the input signal. Pin 3 of the first instrumentation operational amplifier is connected to the thirteenth resistor, one end of the ninth capacitor, and the other end of the seventh capacitor, respectively. The other end of the thirteenth resistor is connected to the positive input signal terminal S1+. Pin 4 of the first instrumentation operational amplifier is connected to one end of the first capacitor and the fourth capacitor through the first resistor, while the other end of the first resistor is connected to the input -12V DC power supply; pin 5 of the first instrumentation operational amplifier is directly connected to the power ground GND. The first instrument operational amplifier's pin 6 is connected to one end of the twelfth resistor, and the other end of the twelfth resistor is connected to the input terminal of the second-stage amplifier circuit module. Pin 7 of the first instrumentation operational amplifier is connected to one end of the second and third capacitors through the fourth resistor. The other ends of the second and third capacitors are connected to the power ground GND. The other end of the fourth resistor is connected to the input +12V DC power supply. Pin 8 of the first instrumentation operational amplifier is connected to pin 1 through the fifteenth resistor.

4. The low-temperature drift two-stage amplifier circuit as described in claim 3, characterized in that, One end of the first transient voltage suppression diode is connected to the negative terminal S1- of the input signal, and the other end is connected to the power ground GND, in order to protect the circuit from the influence of negative transient voltage; One end of the second transient voltage suppression diode is connected to the positive terminal S1+ of the input signal, and the other end is connected to the power supply ground GND, in order to protect the circuit from the influence of positive transient voltage. Pin 1 of the second potentiometer is connected to the negative terminal S1- of the input signal, pin 2 is connected to the positive terminal S1+ of the input signal, and pin 3 is connected to the power ground GND through the fourteenth resistor. This is used to adjust the attenuation or gain of the input signal. The first, second, third, and fourth capacitors serve as filter capacitors, with their other ends connected to the power supply ground (GND) to filter out high-frequency noise in the power supply or signal. The sixth and ninth capacitors are decoupling capacitors, connected between pins 2 and 3 of the first instrumentation operational amplifier and the power ground GND, respectively, to reduce the impact of power fluctuations on amplifier performance. The seventh capacitor is connected across pins 2 and 3 of the first instrumentation operational amplifier as a coupling capacitor for the differential input terminal. The first and fourth resistors are used as current-limiting resistors and are connected between the first, fourth, second, and third capacitors and their corresponding DC power supplies, respectively. The tenth and thirteenth resistors are used as output resistors and are connected between pins 2 and 3 of the first instrumentation operational amplifier and the input signal terminals S1- and S1+, respectively. The fourteenth resistor works in conjunction with the second potentiometer to adjust the bias of the input signal; The fifteenth resistor serves as a feedback resistor, connected between pins 1 and 8 of the first instrument's operational amplifier to set the amplifier's gain.

5. The low-temperature drift two-stage amplifier circuit as described in claim 2, characterized in that, Pin 1 of the first general-purpose precision operational amplifier is connected to pin 5 of the second general-purpose precision operational amplifier through the sixth resistor, forming feedback at the non-inverting input terminal; pin 2 of the first general-purpose precision operational amplifier is connected to one end of the eleventh resistor and one end of the fifth resistor, the other end of the eleventh resistor is connected to the power ground GND, and the other end of the fifth resistor is connected to pin 1 of the first potentiometer; pin 3 of the first general-purpose precision operational amplifier is connected to one end of the twelfth resistor, and the other end of the twelfth resistor is connected to pin 6 of the first instrumentation operational amplifier; pin 4 of the first general-purpose precision operational amplifier is connected to the input -12V DC power supply; pin 8 of the first general-purpose precision operational amplifier is connected to the input +12V DC power supply.

6. The low-temperature drift two-stage amplifier circuit as described in claim 5, characterized in that, Pin 1 of the first potentiometer is connected to the fifth resistor, and pins 2 and 3 of the first potentiometer are connected in parallel to pin 1 of the first general-purpose precision operational amplifier for adjusting the gain or bias of the amplifier. The fifth and eighth capacitors serve as filter capacitors for the positive and negative power supplies, respectively, and their other ends are connected to the power supply ground (GND). The fifth and eleventh resistors serve as bias and current-limiting resistors at the input terminals; The twelfth resistor serves as the signal transmission resistor connecting the first-stage amplifier module and the second-stage amplifier module.

7. The low-temperature drift two-stage amplifier circuit as described in claim 2, characterized in that, Pin 6 of the second general-purpose precision operational amplifier is connected to the power ground (GND) via a second resistor, forming the bias of the inverting input terminal. Pin 7 of the second general-purpose precision operational amplifier is connected to the node between pins 6 and 7 via a third resistor, realizing signal addition. Pin 5 of the second general-purpose precision operational amplifier is connected to one end of an eighth resistor, and the other end of the eighth resistor is connected to the input reference voltage. Pin 5 of the second general-purpose precision operational amplifier is also connected to pin 1 of the first general-purpose precision operational amplifier via a sixth resistor, forming feedback of the non-inverting input terminal. Pin 7 of the second general-purpose precision operational amplifier serves as the output terminal, directly connected to one end of a seventh resistor, and the other end of the seventh resistor is used to output the final output signal.

8. The low-temperature drift two-stage amplifier circuit as described in claim 7, characterized in that, The second and third resistors form the bias and feedback network for the inverting input; the sixth resistor serves as the feedback resistor for the non-inverting input; and the seventh resistor serves as the output resistor. The eighth resistor is used to limit the input reference voltage.

9. The low-temperature drift two-stage amplifier circuit as described in claim 2, characterized in that, The first-stage amplifier circuit module is specifically used for: The input signal is protected by the first transient voltage suppression diode and the second transient voltage suppression diode before being connected to the input terminal of the first instrumentation operational amplifier; The first capacitor, the second capacitor, the third capacitor, the fourth capacitor, and the first resistor and the fourth resistor form a power supply filter network to ensure power supply stability. The sixth, seventh, and ninth capacitors, together with the tenth, thirteenth, and fifteenth resistors, achieve signal filtering and amplification. The second potentiometer is used to adjust the zero position of the input signal.

10. The low-temperature drift two-stage amplifier circuit as described in claim 2, characterized in that, The secondary amplifier circuit module is specifically used for: The received first signal is connected to the input terminal of the first general-purpose precision operational amplifier through the twelfth resistor; The fifth and eighth capacitors, along with the fifth and eleventh resistors, constitute a power supply filter network. The first potentiometer is used to adjust the amplification factor; The addition circuit module is specifically used for: The received second signal and the set reference voltage are input to the second general-purpose precision operational amplifier through the sixth resistor and the eighth resistor; The second, third, and seventh resistors form a feedback network to achieve precise signal adjustment. The final output signal is led out through the seventh resistor.

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