Novel circuit of high-temperature-resistant filter

Abstract

The utility model provides a novel circuit of a high-temperature-resistant filter, which comprises a first operational amplifier U1, a second operational amplifier U2, a third operational amplifier U3, a fourth operational amplifier U4, a fifth operational amplifier U5 and an external adjustable amplifier N1, and the third operational amplifier U3 and a peripheral circuit of the third operational amplifier U3 are used as follower output of a first-stage filter. The output capability of the circuit is increased, the fifth operational amplifier U5 is used as a follower, the loading capability of an output signal is increased, and the filtering characteristic and flexible application of the circuit are greatly improved by adopting two-stage filtering and external adjustable amplification.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit design, in particular to a novel high temperature resistant filter circuit. Background Art

[0002] With the broad development of oil exploration and logging equipment technology, the requirements for the accuracy, linearity and temperature of detection instruments are becoming more and more stringent. The petrochemical industry uses a variety of equipment, such as variable frequency drive transmission equipment, DC drive equipment (winch, pulley, drill plate, drill pipe), variable frequency drive pumps, compressors (mud pumps, centrifugal compressors, vapor compression refrigeration devices) and other power electronic equipment distributed in various application sites in the industry. In large-scale system circuits, filters are indispensable modules in analog circuit systems, and they mainly play the role of frequency selection in the system. However, the current technology and applications can no longer meet the requirements of normal operation in various harsh environments. Utility Model Content

[0003] In view of this, the technical problem to be solved by the present invention is: how to provide a novel high temperature resistant filter circuit to improve the output capacity of the filter circuit and the load capacity of the output signal.

[0004] To achieve the above object, the utility model proposes a novel high temperature resistant filter circuit, which includes a first operational amplifier U1, a second operational amplifier U2, a third operational amplifier U3, a fourth operational amplifier U4, a fifth operational amplifier U5, and an external adjustable amplifier N1;

[0005] The input signal is connected to the same direction terminal of the first operational amplifier U1, and a resistor R1 is connected between the same direction terminal of the first operational amplifier U1 and the ground terminal;

[0006] The inverting end of the first operational amplifier U1 is connected to the output end of the first operational amplifier U1;

[0007] A resistor R2 and a resistor R3 are connected between the output end of the first operational amplifier U1 and the same-direction end of the second operational amplifier U2;

[0008] A capacitor C2 is connected between the in-phase terminal and the ground terminal of the second operational amplifier U2;

[0009] Connected to the output end of the second operational amplifier U2 at a position between the resistor R2 and the resistor R3;

[0010] A resistor R4 and a resistor R5 are connected between the output terminal of the second operational amplifier U2 and the ground terminal;

[0011] The middle of the resistor R4 and the resistor R5 is connected to the reverse end of the second operational amplifier U2;

[0012] The output end of the second operational amplifier U2 is connected to the same-inverting end of the third operational amplifier U3;

[0013] The reverse end of the third operational amplifier U3 is connected to the output end of the third operational amplifier U3 to the third pin of the external adjustable amplifier N1;

[0014] The sixth pin, the seventh pin and the eighth pin of the external adjustable amplifier N1 are used as external adjustment terminals;

[0015] The first pin of the external adjustable amplifier N1 connects the resistor R6 and the resistor R7 to the same direction end of the fourth operational amplifier U4;

[0016] A capacitor C4 is connected between the same-direction end and the ground end of the fourth operational amplifier U4;

[0017] A capacitor C3 is connected between the resistor R6 and the resistor R7 to the output end of the fourth operational amplifier U4;

[0018] The output end of the fourth operational amplifier U4 is connected to the resistor R8 and the resistor R9 to the ground end;

[0019] The inverting end of the fourth operational amplifier U4 is located between the resistor R8 and the resistor R9;

[0020] The inverting end of the fourth operational amplifier U4 is connected to the same-direction end of the fifth operational amplifier U5;

[0021] The non-inverting terminal of the fifth operational amplifier U5 is connected to the resistor R10 and the ground terminal.

[0022] Furthermore, the second pin of the external adjustable amplifier N1 is connected to the ground, and the eighth pin of the external adjustable amplifier N1 is connected to the power supply.

[0023] Compared with the related art, the utility model proposes a new type of high temperature resistant filter circuit, which has the beneficial effect of increasing the output capacity of the circuit by setting the third operational amplifier U3 and its peripheral circuit as the follower output of the first-stage filter, and increasing the load capacity of the output signal by using the fifth operational amplifier U5 as a follower. By adopting two-stage filtering and external adjustable amplification, the filtering characteristics and flexible application of the circuit are greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a circuit diagram of a novel circuit of a high temperature resistant filter in an embodiment of the utility model. DETAILED DESCRIPTION

[0025] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0026] Please refer to the attached Figure 1 As shown, the utility model proposes a new type of high temperature resistant filter circuit, which includes a first operational amplifier U1, a second operational amplifier U2, a third operational amplifier U3, a fourth operational amplifier U4, a fifth operational amplifier U5, and an external adjustable amplifier N1. The circuit is modularly designed, the shell adopts a full gold plating process, and the key components adopt high temperature resistant, bare core components, which greatly enhances the reliability of the system in high temperature and high vibration environments.

[0027] The input signal is connected to the non-inverting terminal of the first operational amplifier U1 , and a resistor R1 is connected between the non-inverting terminal of the first operational amplifier U1 and the ground terminal.

[0028] The inverting terminal of the first operational amplifier U1 is connected to the output terminal of the first operational amplifier U1.

[0029] The resistor R2 and the resistor R3 are connected between the output terminal of the first operational amplifier U1 and the non-inverting terminal of the second operational amplifier U2.

[0030] A capacitor C2 is connected between the non-inverting terminal of the second operational amplifier U2 and the ground terminal.

[0031] The output terminal of the second operational amplifier U2 is connected between the resistor R2 and the resistor R3.

[0032] The resistor R4 and the resistor R5 are connected between the output terminal of the second operational amplifier U2 and the ground terminal.

[0033] The middle of the resistor R4 and the resistor R5 is connected to the inverting terminal of the second operational amplifier U2.

[0034] The output terminal of the second operational amplifier U2 is connected to the non-inverting terminal of the third operational amplifier U3.

[0035] The inverting end of the third operational amplifier U3 is connected to the output end of the third operational amplifier U3 to the third pin of the external adjustable amplifier N1. The third operational amplifier U3 and its peripheral circuit serve as the follower output of the first-stage filter, increasing the output capacity of the circuit.

[0036] The sixth pin, the seventh pin and the eighth pin of the external adjustable amplifier N1 are used as external adjustment terminals. The second pin of the external adjustable amplifier N1 is connected to the ground and can adjust the signal output amplitude. The eighth pin of the external adjustable amplifier N1 is connected to the power supply.

[0037] The first pin of the external adjustable amplifier N1 connects the resistor R6 and the resistor R7 to the same-direction terminal of the fourth operational amplifier U4.

[0038] A capacitor C4 is connected between the non-inverting terminal of the fourth operational amplifier U4 and the ground terminal.

[0039] The middle of the resistor R6 and the resistor R7 is connected to the capacitor C3 and the output terminal of the fourth operational amplifier U4.

[0040] The output terminal of the fourth operational amplifier U4 is connected to the resistor R8 and the resistor R9 to the ground terminal.

[0041] The middle of the resistors R8 and R9 is the inverting terminal of the fourth operational amplifier U4.

[0042] The inverting terminal of the fourth operational amplifier U4 is connected to the non-inverting terminal of the fifth operational amplifier U5.

[0043] The same direction end of the fifth operational amplifier U5 is connected to the resistor R10 to the ground end, and the fifth operational amplifier U is used as a follower to increase the load capacity of the output signal. Finally, it can cooperate with the acquisition module and the transmission module to communicate with the ground.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A novel high temperature resistant filter circuit, characterized in that: It includes a first operational amplifier U1, a second operational amplifier U2, a third operational amplifier U3, a fourth operational amplifier U4, a fifth operational amplifier U5, and an external adjustable amplifier N1; The input signal is connected to the same direction terminal of the first operational amplifier U1, and a resistor R1 is connected between the same direction terminal of the first operational amplifier U1 and the ground terminal; The inverting end of the first operational amplifier U1 is connected to the output end of the first operational amplifier U1; A resistor R2 and a resistor R3 are connected between the output end of the first operational amplifier U1 and the same-direction end of the second operational amplifier U2; A capacitor C2 is connected between the in-phase terminal and the ground terminal of the second operational amplifier U2; Connected to the output end of the second operational amplifier U2 at a position between the resistor R2 and the resistor R3; A resistor R4 and a resistor R5 are connected between the output terminal of the second operational amplifier U2 and the ground terminal; The middle of the resistor R4 and the resistor R5 is connected to the reverse end of the second operational amplifier U2; The output end of the second operational amplifier U2 is connected to the same-inverting end of the third operational amplifier U3; The reverse end of the third operational amplifier U3 is connected to the output end of the third operational amplifier U3 to the third pin of the external adjustable amplifier N1; The sixth pin, the seventh pin and the eighth pin of the external adjustable amplifier N1 are used as external adjustment terminals; The first pin of the external adjustable amplifier N1 connects the resistor R6 and the resistor R7 to the same direction end of the fourth operational amplifier U4; A capacitor C4 is connected between the same-direction end and the ground end of the fourth operational amplifier U4; A capacitor C3 is connected between the resistor R6 and the resistor R7 to the output end of the fourth operational amplifier U4; The output end of the fourth operational amplifier U4 is connected to the resistor R8 and the resistor R9 to the ground end; The inverting end of the fourth operational amplifier U4 is located between the resistor R8 and the resistor R9; The inverting end of the fourth operational amplifier U4 is connected to the same-direction end of the fifth operational amplifier U5; The non-inverting terminal of the fifth operational amplifier U5 is connected to the resistor R10 and the ground terminal.

2. The novel high temperature resistant filter circuit according to claim 1, characterized in that: The second pin of the external adjustable amplifier N1 is connected to the ground, and the eighth pin of the external adjustable amplifier N1 is connected to the power supply.

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