Operational amplifier circuit with variable output response characteristics

Abstract

The utility model discloses an operational amplifier circuit with variable output response characteristics in the technical field of circuit design, which comprises an operational amplifier, and a direct current bias compensation circuit is arranged between the output end and the inverted input end of the operational amplifier. The compensation circuit comprises two capacitors and a resistor, one input end of an operational amplifier is connected with one end of a first capacitor and one end of a second capacitor, the other end of the first capacitor is connected with one end of a first resistor and the direct current bias circuit, and the other end of the second capacitor is connected with the other end of a second resistor. The other end of the first resistor and the other end of the second capacitor are connected with the output end of the operational amplifier. According to the utility model, the capacitor and the resistor are connected with the direct-current bias circuit, so that the gain of the operational amplifier circuit can be changed, and the response performance of circuit output is changed; moreover, the whole direct-current bias compensation circuit is simple in structure, few components are used, and the power consumption and the production difficulty of the whole circuit are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit design, in particular to an operational amplifier circuit with variable output response characteristics. Background Art

[0002] An operational amplifier (OPA) is an electronic integrated circuit containing a multi-stage amplification circuit with two inputs and one output. OPA's offer high amplification factors and come in a wide variety of types, making them widely used in nearly every industry. Output gain is a key metric for measuring an OPA's performance and a crucial parameter to consider during circuit design. In practical applications, the voltages at its two inputs determine its output state. However, existing OPA gain is fixed upon fabrication.

[0003] To increase the output response of operational amplifiers, variable gain circuit designs are currently being employed in operational amplifiers. For example, Chinese invention patent publication number CN115242198A discloses a bias voltage circuit and a gain-enhanced operational amplifier. These circuits bias the non-inverting input terminals of auxiliary amplifiers AMP1 and AMP2 by setting a bias circuit, thereby ensuring the output of the two auxiliary amplifiers and providing a suitable bias voltage for the second common-source gate. This allows the operational amplifier to have greater gain and bandwidth properties.

[0004] However, in the operational amplifier circuit of this structure, the bias circuit includes an input matching circuit, a reference current source, a bias voltage generating circuit, etc. The structure of the entire bias circuit is complex, which increases the output response of the operational amplifier while bringing about greater power consumption and occupying more circuit resources.

[0005] The above defects deserve improvement. Utility Model Content

[0006] To overcome the shortcomings of existing technologies, the present invention provides an operational amplifier circuit with variable output response characteristics. The operational amplifier circuit is connected to a DC bias circuit via capacitors and resistors, thereby varying the gain of the operational amplifier circuit and changing the response characteristics of the circuit output. Furthermore, the entire DC bias compensation circuit of the present invention has a simple structure and uses fewer components, thereby reducing power consumption and production difficulty of the entire circuit.

[0007] The technical solution of this utility model is as follows:

[0008] An operational amplifier circuit with variable output response characteristics, comprising an operational amplifier, wherein a non-inverting input terminal of the operational amplifier is connected to a non-inverting input circuit, and an inverting input terminal of the operational amplifier is connected to an inverting input circuit, and wherein a DC offset compensation circuit is provided between the output terminal of the operational amplifier and the inverting input terminal thereof;

[0009] The DC bias compensation circuit includes a compensation circuit and a DC bias circuit:

[0010] The compensation circuit includes a first capacitor, a second capacitor, and a first resistor, the inverting input terminal of the operational amplifier is connected to one end of the first capacitor and one end of the second capacitor, the other end of the first capacitor is connected to one end of the first resistor, and the other end of the first resistor and the other end of the second capacitor are connected to the output terminal of the operational amplifier;

[0011] The DC bias circuit is connected to a common end of the first capacitor and the first resistor.

[0012] The utility model according to the above solution is characterized in that it further includes an AC source, one end of which is grounded, and the other end of which is connected to the input end of the operational amplifier through the non-inverting input circuit / the inverting input circuit.

[0013] The utility model according to the above solution is characterized in that the power supply terminal of the operational amplifier is connected to the power supply, and the ground terminal thereof is grounded.

[0014] The utility model according to the above solution is characterized in that the DC bias circuit includes one or more DC sources, one end of the DC source is grounded, and the other end is connected to the common end of the first capacitor and the first resistor through the bias circuit.

[0015] Furthermore, the bias circuit includes a diode, one end of which is connected to one end of the DC source, and the other end of which is connected to a common end of the first capacitor and the first resistor.

[0016] Furthermore, the bias circuit includes a diode, an anode of the diode is connected to the positive electrode of the DC source, and a cathode of the diode is connected to a common end of the first capacitor and the first resistor.

[0017] Furthermore, the bias circuit includes a diode, a cathode of the diode is connected to the positive electrode of the DC source, and an anode of the diode is connected to a common end of the first capacitor and the first resistor.

[0018] Furthermore, the bias circuit includes a bias operational amplifier and a diode, one input end of the bias operational amplifier is connected to the DC source, and its output end is connected to one end of the diode, the other end of the diode is connected to the other input end of the bias operational amplifier, and the other end of the diode is also connected to the common end of the first capacitor and the first resistor.

[0019] Furthermore, the output end of the bias operational amplifier is connected to the anode of the diode, and the cathode of the diode is connected to the common end of the first capacitor and the first resistor.

[0020] Furthermore, the output end of the bias operational amplifier is connected to the cathode of the diode, and the anode of the diode is connected to the common end of the first capacitor and the first resistor.

[0021] The utility model according to the above solution has the following beneficial effects:

[0022] This utility model, by connecting capacitors and resistors to a DC bias circuit, can alter the gain of an operational amplifier circuit and thus change the response characteristics of the circuit's output. Specifically, the DC bias circuit and the compensation circuit work together to influence the input characteristics (i.e., gain) of the operational amplifier circuit. By increasing the gain, the operational amplifier responds faster to step signals and reduces settling time.

[0023] The entire DC bias compensation circuit of the utility model has a simple structure and uses fewer components, thereby reducing power consumption and production difficulty of the entire circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a circuit diagram of the first embodiment of the present utility model;

[0025] Figure 2 for Figure 1 Equivalent circuit diagram of

[0026] Figure 3 This is a circuit diagram of the second embodiment of the present utility model;

[0027] Figure 4 This is a circuit diagram of the third embodiment of the present utility model;

[0028] Figure 5 for Figure 4 Equivalent circuit diagram of

[0029] Figure 6 This is a circuit diagram of the fourth embodiment of the present utility model;

[0030] Figure 7 This is a circuit diagram of the fifth embodiment of the present utility model;

[0031] Figure 8 This is a circuit diagram of the sixth embodiment of the present utility model;

[0032] Figure 9 This is a circuit diagram of Embodiment 7 of the present utility model;

[0033] Figure 10This is a circuit diagram of the eighth embodiment of the present utility model;

[0034] Figure 11 It is a simulation curve diagram comparing the utility model with the prior art. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0036] like Figures 1 to 11 As shown, in order to solve the defects of the existing amplifier circuit with fixed output response and complex bias circuit, the utility model proposes an operational amplifier circuit with variable output response characteristics. The DC bias compensation circuit is applied to the amplifier circuit to change the gain of the amplifier circuit and change the response characteristics of its output and input. In addition, the entire DC bias compensation circuit has a simple structure and can be appropriately adjusted according to different needs, and has a wide range of applications.

[0037] The operational amplifier circuit with variable output response characteristics includes an operational amplifier and a DC bias compensation circuit. Specifically, the operational amplifier has a negative feedback circuit, the non-inverting input terminal of the operational amplifier is connected to the non-inverting input circuit, and the inverting input terminal of the operational amplifier is connected to the inverting input circuit. The DC bias compensation circuit is arranged between the output terminal of the operational amplifier and the inverting input terminal thereof, and is used for DC bias compensation to form gain adjustment.

[0038] In the specific implementation process, the DC bias compensation circuit includes a compensation circuit and a DC bias circuit:

[0039] The compensation circuit includes a first capacitor, a second capacitor, and a first resistor. The inverting input terminal of the operational amplifier is connected to one end of the first capacitor and one end of the second capacitor, the other end of the first capacitor is connected to one end of the first resistor, and the other end of the first resistor and the other end of the second capacitor are connected to the output terminal of the operational amplifier; and the DC bias circuit is connected to the common end of the first capacitor and the first resistor.

[0040] Preferably, the operational amplifier circuit with variable output response characteristics further includes an AC source, one end of which is grounded, and the other end of which is connected to the input end of the operational amplifier via the non-inverting input circuit / inverting input circuit. The operational amplifier is connected to a single power supply, that is, the power supply end of the operational amplifier is connected to the power supply, and the ground end of the operational amplifier is grounded. Example 1

[0041] like Figure 1 、 Figure 2 、 Figure 11As shown, this embodiment provides an operational amplifier circuit with variable output response characteristics, wherein a DC bias circuit includes a DC source DC1, a negative electrode of the DC source DC1 is grounded, and a positive electrode thereof is connected to a common end of a first capacitor C1 and a first resistor R1 through a bias circuit.

[0042] In this circuit, the bias circuit includes a diode D1 , an anode of the diode D1 is connected to the positive electrode of the DC source DC1 , and a cathode of the diode D1 is connected to the common end of the first capacitor C1 and the first resistor R1 .

[0043] The utility model uses the first capacitor C1, the first resistor R1 and the diode D1 (unidirectional injection voltage) to realize the DC source injecting voltage between the first capacitor C1 and the first resistor R1. By adding the compensation circuit composed of the first capacitor C1, the first resistor R1 and the second capacitor C2 and the bias circuit composed of the diode D1 and the DC source DC1, the gain of the operational amplifier circuit is changed, and the response characteristics of the circuit output are changed. Based on the above Figure 2 The equivalent circuit shown is Figure 11 The simulation curve shown in the figure shows that the principle is: when the voltage of the operational amplifier's non-inverting input terminal is lower than that of its inverting input terminal, the output Vo of the operational amplifier is low. Figure 2 As can be seen from the equivalent circuit shown, the DC source DC1 is equivalent to a short circuit, and the output of the operational amplifier circuit is grounded through the diode D1.

[0044] exist Figure 11 In FIG, L1 represents the phase curve of the amplifier circuit in the prior art, L2 represents the gain curve of the amplifier circuit in the prior art, L3 represents the phase curve of the amplifier circuit in this embodiment, and L4 represents the gain curve of the amplifier circuit in this embodiment. Figure 11 The simulation results show that in the low frequency band, the gain curve of the amplifier circuit in this embodiment is significantly higher than the gain of the amplifier circuit in the prior art. Compared with the prior art, this embodiment can change the gain of the operational amplifier circuit, thereby changing the response of the amplifier circuit. Example 2

[0045] like Figure 3 As shown, different from the first embodiment, in this embodiment, the cathode of the diode D1 is connected to the positive electrode of the DC source DC1, and the anode thereof is connected to the common end of the first capacitor C1 and the first resistor R1.

[0046] Figure 3 The embodiment shown is Figure 1 The equivalent circuits of the illustrated embodiments are similar and have the same implementation principles, which will not be described again here. Example 3

[0047] like Figure 4 、 Figure 5As shown, unlike the first embodiment, in this embodiment, the bias circuit includes a bias operational amplifier U2 and a diode D1. The non-inverting input terminal of the bias operational amplifier U2 is connected to the DC source DC1, and its output terminal is connected to one end of the diode D1. The other end of the diode D1 is connected to the inverting input terminal of the bias operational amplifier U2. The other end of the diode D1 is also connected to the common end of the first capacitor C1 and the first resistor R1. The power supply terminal of the bias operational amplifier U2 is connected to the bias power supply DC2, and its ground terminal is grounded. In other embodiments, the DC source can also be implemented by a precision rectifier circuit, which is not specifically limited in this utility model.

[0048] Specifically, in this embodiment, the output end of the bias operational amplifier U2 is connected to the anode of the diode D1 , and the cathode of the diode D1 is connected to the common end of the first capacitor C1 and the first resistor R1 .

[0049] Figure 5 for Figure 4 In the AC equivalent circuit, the DC source DC1 is equivalent to a short circuit, so the non-inverting input terminal of the bias operational amplifier U2 is grounded. Example 4

[0050] like Figure 6 As shown, different from the third embodiment, in this embodiment, the output end of the bias operational amplifier U2 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to the common end of the first capacitor C1 and the first resistor R1.

[0051] Figure 6 The embodiment shown is Figure 4 The equivalent circuits of the illustrated embodiments are similar and have the same implementation principles, which will not be described again here. Example 5

[0052] like Figure 7 As shown, unlike the first embodiment, the DC bias circuit in this embodiment includes two DC sources (including a first DC source DC1 and a second DC source DC2). The cathode of the first DC source DC1 is grounded, and the positive electrode thereof is connected to the common end of the first capacitor C1 and the first resistor R1 through the first bias circuit. The cathode of the second DC source DC2 is grounded, and the positive electrode thereof is connected to the common end of the first capacitor C1 and the first resistor R1 through the second bias circuit.

[0053] In this embodiment, the first bias circuit includes a first diode D1, the anode of which is connected to the positive electrode of the first DC source DC1, and the cathode of which is connected to the common end of the first capacitor C1 and the first resistor R1. The second bias circuit includes a second diode D2, the cathode of which is connected to the positive electrode of the second DC source DC2, and the anode of which is connected to the common end of the first capacitor C1 and the first resistor R1.

[0054] In this embodiment, the compensation circuit is connected to two DC bias circuits. Compared with the first embodiment, this embodiment can change the response characteristics of two outputs simultaneously through the two DC bias circuits. Example 6

[0055] like Figure 8 As shown, different from the fifth embodiment, each bias circuit in this embodiment includes a corresponding bias operational amplifier and a diode.

[0056] Specifically, the first bias circuit includes a first bias operational amplifier and a first diode D1. The non-inverting input of the first bias operational amplifier is connected to the first DC source, and the output of the first bias operational amplifier is connected to one end of the first diode D1. The other end of the first diode D1 is connected to the inverting input of the first bias operational amplifier. The other end of the first diode D1 is also connected to the common end of the first capacitor C1 and the first resistor R1. The power supply of the first bias operational amplifier is connected to the first bias power supply, and the ground terminal of the first bias operational amplifier is grounded. In this embodiment, the output of the first bias operational amplifier is connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected to the common end of the first capacitor C1 and the first resistor R1.

[0057] The second bias circuit includes a second bias operational amplifier and a second diode D2. The non-inverting input of the second bias operational amplifier is connected to the second DC source, and the output of the second bias operational amplifier is connected to one end of the second diode D2. The other end of the second diode D2 is connected to the inverting input of the second bias operational amplifier. The other end of the second diode D2 is also connected to the common end of the first capacitor C1 and the first resistor R1. The power supply of the second bias operational amplifier is connected to the second bias power supply, and the ground end of the second bias operational amplifier is grounded. In this embodiment, the output of the second bias operational amplifier is connected to the cathode of the second diode D2, and the anode of the second diode D2 is connected to the common end of the first capacitor C1 and the first resistor R1. Example 7

[0058] like Figure 9 As shown, the difference from the fifth embodiment is that in this embodiment, the bias circuit structures in the two DC bias circuits are different.

[0059] Specifically, the first bias circuit includes a first bias operational amplifier and a first diode D1. The non-inverting input of the first bias operational amplifier is connected to a first DC source, the output of the first bias operational amplifier is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to the inverting input of the first bias operational amplifier, and the cathode of the first diode D1 is also connected to the common terminal of the first capacitor C1 and the first resistor R1. The power supply terminal of the first bias operational amplifier is connected to the first bias power supply, and the ground terminal of the first bias operational amplifier is grounded.

[0060] The second bias circuit includes a second diode D2 , wherein the cathode of the second diode D2 is connected to the positive electrode of the second DC source DC2 , and the anode of the second diode D2 is connected to the common end of the first capacitor C1 and the first resistor R1 . Example 8

[0061] like Figure 10 As shown, the difference from the seventh embodiment is that in this embodiment, the connection direction of the diodes in the two-way bias circuit structure is opposite to that of the seventh embodiment.

[0062] Specifically, the first bias circuit includes a first bias operational amplifier and a first diode D1. The non-inverting input of the first bias operational amplifier is connected to the first DC source, the output of the first bias operational amplifier is connected to the cathode of the first diode D1, the anode of the first diode D1 is connected to the inverting input of the first bias operational amplifier, and the anode of the first diode D1 is also connected to the common terminal of the first capacitor C1 and the first resistor R1. The power supply terminal of the first bias operational amplifier is connected to the first bias power supply, and the ground terminal of the first bias operational amplifier is grounded.

[0063] The second bias circuit includes a second diode D2 , an anode of the second diode D2 is connected to the positive electrode of the second DC source DC2 , and a cathode of the second diode D2 is connected to the common end of the first capacitor C1 and the first resistor R1 .

[0064] Without violating the principles of the present invention, the specific circuit structures of the various embodiments may be adjusted. Based on the above embodiments, the specific structure of the DC bias circuit of the present invention may also be appropriately modified, including but not limited to: the number of DC bias circuit paths, the connection direction of the diodes, the connection direction of the DC source, and the swapping of the non-inverting and inverting inputs of the bias operational amplifier.

[0065] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the claims attached to this utility model.

[0066] The above is an exemplary description of the present utility model patent in conjunction with the accompanying drawings. It is obvious that the implementation of the present utility model patent is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present utility model patent, or the concept and technical solution of the present utility model patent are directly applied to other occasions without improvement, they are all within the scope of protection of the present utility model.

Claims

1. An operational amplifier circuit with variable output response characteristics, comprising an operational amplifier, wherein the non-inverting input terminal of the operational amplifier is connected to the non-inverting input circuit, and the inverting input terminal of the operational amplifier is connected to the inverting input circuit, characterized in that: A DC bias compensation circuit is provided between the output terminal of the operational amplifier and the inverting input terminal thereof; The DC bias compensation circuit includes a compensation circuit and a DC bias circuit: The compensation circuit includes a first capacitor, a second capacitor, and a first resistor, the inverting input terminal of the operational amplifier is connected to one end of the first capacitor and one end of the second capacitor, the other end of the first capacitor is connected to one end of the first resistor, and the other end of the first resistor and the other end of the second capacitor are connected to the output terminal of the operational amplifier; The DC bias circuit is connected to a common end of the first capacitor and the first resistor.

2. The operational amplifier circuit with variable output response characteristics according to claim 1, wherein: It also includes an AC source, one end of which is grounded, and the other end of which is connected to the input end of the operational amplifier through the non-inverting input circuit / the inverting input circuit.

3. The operational amplifier circuit with variable output response characteristics according to claim 1, wherein: The power supply terminal of the operational amplifier is connected to the power supply, and the ground terminal thereof is grounded.

4. The operational amplifier circuit with variable output response characteristics according to any one of claims 1 to 3, wherein: The DC bias circuit includes one or more DC sources, one end of which is grounded, and the other end of which is connected to a common end of the first capacitor and the first resistor through a bias circuit.

5. The operational amplifier circuit with variable output response characteristics according to claim 4, wherein: The bias circuit includes a diode, one end of which is connected to one end of the DC source, and the other end of which is connected to a common end of the first capacitor and the first resistor.

6. The operational amplifier circuit with variable output response characteristics according to claim 5, wherein: The bias circuit includes a diode, an anode of the diode is connected to the positive electrode of the DC source, and a cathode of the diode is connected to a common end of the first capacitor and the first resistor.

7. The operational amplifier circuit with variable output response characteristics according to claim 5, wherein: The bias circuit includes a diode, a cathode of the diode is connected to the positive electrode of the DC source, and an anode of the diode is connected to a common end of the first capacitor and the first resistor.

8. The operational amplifier circuit with variable output response characteristics according to claim 4, wherein: The bias circuit includes a bias operational amplifier and a diode. One input end of the bias operational amplifier is connected to the DC source, and an output end of the bias operational amplifier is connected to one end of the diode. The other end of the diode is connected to the other input end of the bias operational amplifier. The other end of the diode is also connected to a common end of the first capacitor and the first resistor.

9. The operational amplifier circuit with variable output response characteristics according to claim 8, wherein: The output end of the bias operational amplifier is connected to the anode of the diode, and the cathode of the diode is connected to the common end of the first capacitor and the first resistor.

10. The operational amplifier circuit with variable output response characteristics according to claim 8, wherein: The output end of the bias operational amplifier is connected to the cathode of the diode, and the anode of the diode is connected to the common end of the first capacitor and the first resistor.

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