Operational amplifier circuit for automatic gear switching

Abstract

The utility model belongs to the field of operational amplifier circuits, and discloses an operational amplifier circuit for automatic gear switching, which comprises a resistor R30, a resistor R32, a capacitor C201, a resistor R37, a capacitor C91, an operational amplifier U1, an operational amplifier U2, a capacitor C131, a capacitor C111, a capacitor C101, a resistor R151, a resistor R311, a capacitor C208, a capacitor C209, a capacitor C210, a capacitor C211, a resistor R321, a resistor R322, a resistor R331, a resistor R332, a resistor R351, a resistor R361, a chip U9, a resistor R341, a diode D211 and a diode D111. The internal resistance of the analog switch is removed from the negative feedback loop of the operational amplifier circuit, so that the influence of the internal resistance of the analog switch on the amplification factor of the operational amplifier circuit is reduced, and the stability of output signals is enhanced.

Description

Technical Field

[0001] This utility model relates to the field of operational amplifier circuits, and in particular to an operational amplifier circuit for automatic band switching. Background Technology

[0002] An operational amplifier (op-amp) circuit with automatic gain switching is a circuit design that can automatically adjust its gain based on the characteristics of the input signal or external control signals. Its core concept is to dynamically change the gain of the operational amplifier by switching different feedback resistors, thereby allowing the circuit to flexibly adapt to various signal conditions and functional requirements. Due to its flexibility and efficiency, the automatic gain switching op-amp circuit is very important in modern electronic applications, especially in situations requiring high precision and stability.

[0003] Currently, devices using operational amplifier circuits with automatic switching mainly employ the activation of analog switches to change the resistance value of the feedback resistor in the operational amplifier circuit, thereby achieving switching between different levels. However, existing devices have shortcomings in the stability of the operational amplifier's amplification factor, and the output value of the operational amplifier circuit exhibits significant temperature drift.

[0004] Therefore, how to provide an operational amplifier circuit for automatic band switching is an urgent problem to be solved. Utility Model Content

[0005] This utility model provides an operational amplifier circuit for automatic band switching to solve the problem of insufficient stability of the amplification factor of operational amplifiers in the prior art.

[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or to describe the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0007] According to an embodiment of the present invention, an operational amplifier circuit for automatic gear switching is provided.

[0008] In one embodiment, an operational amplifier circuit for automatic band switching includes resistors R30 and R32, capacitors C201, R37, and C91, operational amplifiers U1 and U2, capacitors C131, C111, and C101, resistors R151 and R311, capacitors C208, C209, C210, and C211, resistors R321, R322, R331, R332, R351, and R361, chip U9, resistor R341, diode D211, and diode... D111; where, one end of resistor R30 is connected in sequence to one end of capacitor C91, one end of resistor R151, one end of capacitor C101, and the sixth terminal of operational amplifier U1; one end of resistor R32 is connected in sequence to the other end of capacitor C91, one end of resistor R37, one end of capacitor C201, and the fifth terminal of operational amplifier U1; the other end of resistor R37 is connected to the other end of capacitor C201; the fourth terminal of operational amplifier U1 is connected to capacitor C131; the eighth terminal of operational amplifier U1 is connected to capacitor C111; and the seventh terminal of operational amplifier U1 is connected in sequence to the other end of resistor R151, capacitor C101, and the sixth terminal of operational amplifier U1. The other end of C101 is connected to one end of resistor R311; the other end of resistor R311 is connected in sequence to one end of capacitor C211, one end of resistor R321, and the third terminal of chip U9; the other end of resistor R321 is connected to one end of resistor R322; the other end of resistor R322 is connected in sequence to one end of resistor R331, one end of capacitor C209, and the fourteenth terminal of chip U9; the other end of resistor R331 is connected to one end of resistor R332; the other end of resistor R332 is connected in sequence to one end of resistor R351, one end of capacitor C210, and chip U9. The eleventh terminal is connected, and the other end of resistor R351 is connected in sequence to one end of resistor R361, one end of capacitor C208, and the sixth terminal of chip U9. The other end of capacitor C211 is connected in sequence to the other end of capacitor C209, the other end of capacitor C210, the other end of capacitor C208, the other end of resistor R361, the positive terminal of diode D211, the negative terminal of diode D111, and the first terminal of operational amplifier U2. The third terminal of operational amplifier U2 is connected to resistor R341, and the second terminal of operational amplifier U2 is connected to the second, fifteenth, tenth, and seventh terminals of chip U9.

[0009] In one embodiment, the negative terminal of diode D211 is connected to a +5V voltage, and the positive terminal of diode D111 is grounded.

[0010] In one embodiment, chip U9 is an analog switch chip, and the fifth terminal of chip U9 is grounded.

[0011] In one embodiment, both op-amp U1 and op-amp U2 are dual-channel operational amplifiers.

[0012] In one embodiment, the ends of capacitors C111 and C131 furthest from op-amp U1 are both grounded.

[0013] In one embodiment, the end of resistor R341 furthest from op-amp U2 is grounded.

[0014] The technical solution provided by this utility model embodiment may include the following beneficial effects:

[0015] This invention removes the internal resistance of the analog switch from the negative feedback loop of the operational amplifier circuit, reducing the impact of the analog switch's internal resistance on the operational amplifier's amplification factor, thereby enhancing the stability of the output signal. Compared to operational amplifier circuits commonly used for band switching, this invention uses one less analog switch and related resistors, saving cost and PCB space. Furthermore, by isolating the analog switch from the operational amplifier's amplification factor calculation circuit, it reduces changes in the analog switch's internal resistance caused by input voltage, temperature, and other variations, thus reducing output value fluctuations and making the operational amplifier circuit's output more stable.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the present invention. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the present invention.

[0018] Figure 1 This is one of the schematic diagrams of an operational amplifier circuit for automatic band switching, according to an exemplary embodiment;

[0019] Figure 2 This is a second schematic diagram of an operational amplifier circuit for automatic band switching, according to an exemplary embodiment.

[0020] Figure 3 This is the third schematic diagram of an operational amplifier circuit for automatic band switching, according to an exemplary embodiment.

[0021] Figure 4 The on-resistance and V shown according to an exemplary embodiment D Relationship diagram between (input voltage) and unipolar power supply voltage;

[0022] Figure 5 The on-resistance and V shown according to an exemplary embodiment D The relationship between the voltage and the bipolar power supply voltage is shown in the diagram.

[0023] Figure 6 The on-resistance and V shown according to an exemplary embodiment D A graph showing the relationship between voltage and temperature for a bipolar power supply;

[0024] Figure 7 The on-resistance and V shown according to an exemplary embodiment D A graph showing the relationship between voltage and temperature for a unipolar power supply;

[0025] Figure 8 It is one of the schematic diagrams of the existing original circuit;

[0026] Figure 9 This is the second schematic diagram of the existing original circuit. Detailed Implementation

[0027] The following description and accompanying drawings fully illustrate specific embodiments described herein to enable those skilled in the art to practice them. Some embodiments may include or substitute parts and features of other embodiments. The scope of the embodiments herein encompasses the entire scope of the claims and all available equivalents thereof. Throughout this document, the terms “first,” “second,” etc., are used only to distinguish one element from another without requiring or implying any actual relationship or order between the elements. Indeed, a first element can also be referred to as a second element, and vice versa. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure, apparatus, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a structure, apparatus, or device. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the structure, apparatus, or device that includes said element. The various embodiments described herein are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0028] The terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" used in this document to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings. They are used solely for the convenience of describing this document and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In the description herein, unless otherwise specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two elements; they can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0029] In this document, unless otherwise stated, the term "multiple" means two or more.

[0030] In this article, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0031] In this article, the term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0032] It should be understood that although the steps in the flowchart are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order constraint on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the diagram may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0033] The modules in the apparatus or system of this application can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0034] Where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other.

[0035] Figures 1-3 An embodiment of the operational amplifier circuit for automatic gear switching according to this invention is shown. Figure 1 line segment ① and Figure 2 Connect line segment ① in the middle. Figure 2 Line segments ② and ③ in the diagram are respectively with Figure 3 Connect line segments ② and ③ in the diagram.

[0036] In this optional embodiment, the operational amplifier circuit for automatic gear switching includes: resistors R30 and R32, capacitors C201, R37, and C91, operational amplifiers U1 and U2, capacitors C131, C111, and C101, resistors R151 and R311, capacitors C208 and C209, capacitors C210 and C211, resistors R321, R322, R331, R332, R351, and R361, chip U9, resistor R341, diode D211, and two... Transistor D111; wherein, one end of resistor R30 is connected in sequence to one end of capacitor C91, one end of resistor R151, one end of capacitor C101, and the sixth terminal of operational amplifier U1; one end of resistor R32 is connected in sequence to the other end of capacitor C91, one end of resistor R37, one end of capacitor C201, and the fifth terminal of operational amplifier U1; the other end of resistor R37 is connected to the other end of capacitor C201; the fourth terminal of operational amplifier U1 is connected to capacitor C131; the eighth terminal of operational amplifier U1 is connected to capacitor C111; and the seventh terminal of operational amplifier U1 is connected in sequence to the other end of resistor R151, one end of capacitor R151, one end of capacitor C101, and the sixth terminal of operational amplifier U1. The other end of capacitor C101 is connected to one end of resistor R311; the other end of resistor R311 is connected in sequence to one end of capacitor C211, one end of resistor R321, and the third terminal of chip U9; the other end of resistor R321 is connected to one end of resistor R322; the other end of resistor R322 is connected in sequence to one end of resistor R331, one end of capacitor C209, and the fourteenth terminal of chip U9; the other end of resistor R331 is connected to one end of resistor R332; the other end of resistor R332 is connected in sequence to one end of resistor R351, one end of capacitor C210, and the fourteenth terminal of chip U9. The eleventh terminal of 9 is connected, and the other end of resistor R351 is connected in sequence to one end of resistor R361, one end of capacitor C208, and the sixth terminal of chip U9. The other end of capacitor C211 is connected in sequence to the other end of capacitor C209, the other end of capacitor C210, the other end of capacitor C208, the other end of resistor R361, the positive terminal of diode D211, the negative terminal of diode D111, and the first terminal of operational amplifier U2. The third terminal of operational amplifier U2 is connected to resistor R341, and the second terminal of operational amplifier U2 is connected to the second, fifteenth, tenth, and seventh terminals of chip U9.

[0037] In this optional embodiment, the negative terminal of diode D211 is connected to a +5V voltage, and the positive terminal of diode D111 is grounded.

[0038] In this optional embodiment, chip U9 is an analog switch chip, and the fifth terminal of chip U9 is grounded.

[0039] In this optional embodiment, both op-amp U1 and op-amp U2 are dual-channel operational amplifiers.

[0040] In this alternative embodiment, the ends of capacitors C111 and C131 furthest from op-amp U1 are both grounded.

[0041] In this alternative embodiment, the end of resistor R341 furthest from op-amp U2 is grounded.

[0042] To facilitate understanding of the above-mentioned technical solution of this utility model, the following further explains the above-mentioned technical solution of this utility model from the perspective of architecture and principle, as follows:

[0043] The specifications of the electronic components in an operational amplifier circuit for automatic switching according to this invention are shown in Table 1.

[0044] Table 1 Specifications of Electronic Components

[0045]

[0046]

[0047] The resistors in the circuit are high-precision resistors with low temperature drift coefficients to reduce the impact of ambient temperature changes on the operational amplifier circuit.

[0048] The present invention moves the analog switch out of the feedback loop of the operational amplifier circuit to reduce the influence of the internal resistance of the analog switch on the amplification factor of the operational amplifier circuit.

[0049] The operational amplifier gain of the original circuit is calculated as follows (the internal resistance of the analog switch is set to rk):

[0050] S1 and D1 are closed:

[0051]

[0052] S2 and D2 are closed:

[0053]

[0054] S3 and D3 are closed:

[0055]

[0056] S4 and D4 are closed:

[0057]

[0058] Ideally (r = 0), the magnification factors are 100, 20, 5, and 1 respectively.

[0059] Assuming the internal resistance of the analog switch is 80Ω, r=0.08, the amplification factors are 100.8, 20.8, 5.8, and 1.8 respectively.

[0060] Assume the internal resistance of the analog switch is 100Ω, r = 0.1, and the amplification factors are 101, 21, 6, and 2 respectively.

[0061] Assuming the internal resistance of the analog switch is 120Ω, r=0.12, the amplification factors are 101.2, 21.2, 6.2, and 2.2 respectively.

[0062] It is evident that changes in the internal resistance of the analog switch directly affect the amplification factor of the operational amplifier circuit. Furthermore, the schematic diagram of the original circuit, such as... Figures 8-9 As shown, Figure 8 line segment ④ and Figure 9 Connect line segment ④ in the diagram.

[0063] The operational amplifier amplification factor of this utility model is calculated as follows (the internal resistance of the analog switch is set to rk):

[0064] S1 and D1 are closed:

[0065]

[0066] S2 and D2 are closed:

[0067]

[0068] S3 and D3 are closed:

[0069]

[0070] S4 and D4 are closed:

[0071]

[0072] Ideally (r=0), the magnification factors are 100, 17.5, 3.75, and 1, respectively.

[0073] Assuming the internal resistance of the analog switch is 80Ω and r = 0.08, the amplification factors are 92.59, 17.16, 3.71, and 0.992 respectively.

[0074] Assuming the internal resistance of the analog switch is 100Ω, r = 0.1, the amplification factors are 90.91, 17.07, 3.70, and 0.990 respectively.

[0075] Assuming the internal resistance of the analog switch is 120Ω and r = 0.12, the amplification factors are 89.29, 16.99, 3.69, and 0.988 respectively.

[0076] The effect of changes in the internal resistance of an analog switch on the amplification factor is less than that of the original circuit.

[0077] like Figures 4-7As shown, analog switches differ from load switches. Load switches can handle large currents because their on-resistance is very low. Analog switches essentially perform time-division multiplexing when system interface resources are insufficient. The on-resistance of an analog switch is the resistance inserted into the signal path after the switch path is connected. This on-resistance changes with input voltage, temperature, and supply voltage. Changes in on-resistance cause fluctuations in the operational amplifier's amplification factor, resulting in output signal fluctuations. Where r... DS(ON) To simulate the on-resistance of a switch; V D V+ and V- represent the input voltage; V+ and V- represent the Power-Supply Range; T A This refers to the operating temperature.

[0078] This invention is not limited to the structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this invention is limited only by the appended claims.

Claims

1. An operational amplifier circuit for automatic band switching, characterized in that, The operational amplifier circuit used for automatic switching consists of resistors R30 and R32, capacitors C201, R37, and C91, operational amplifiers U1 and U2, capacitors C131, C111, and C101, resistors R151 and R311, capacitors C208, C209, C210, and C211, resistors R321, R322, R331, R332, R351, and R361, chip U9, resistor R341, diodes D211 and D111. One end of resistor R30 is sequentially connected to one end of capacitor C91, one end of resistor R151, one end of capacitor C101, and the sixth terminal of operational amplifier U1. One end of resistor R32 is sequentially connected to the other end of capacitor C91, one end of resistor R37, one end of capacitor C201, and the fifth terminal of operational amplifier U1. The other end of resistor R37 is connected to the other end of capacitor C201. The fourth terminal of operational amplifier U1 is connected to capacitor C131. The eighth terminal of operational amplifier U1 is connected to capacitor C111. The seventh terminal of operational amplifier U1 is sequentially connected to the other end of resistor R151, the other end of capacitor C101, and one end of resistor R311. The other end of resistor R311 is sequentially connected to one end of capacitor C211, one end of resistor R321, and the third terminal of chip U9. The other end of resistor R321 is connected to one end of resistor R322. The resistor R331 is connected to one end of the resistor R331, one end of the capacitor C209, and the fourteenth terminal of the chip U9 in sequence. The other end of the resistor R331 is connected to one end of the resistor R332. The other end of the resistor R332 is connected to one end of the resistor R351, one end of the capacitor C210, and the eleventh terminal of the chip U9 in sequence. The other end of the resistor R351 is connected to one end of the resistor R361, one end of the capacitor C208, and the sixth terminal of the chip U9 in sequence. The other end of the capacitor C211 is connected to the other end of the capacitor C209, the other end of the capacitor C210, the other end of the capacitor C208, the other end of the resistor R361, the positive terminal of the diode D211, the negative terminal of the diode D111, and the first terminal of the operational amplifier U2 in sequence. The third terminal of the operational amplifier U2 is connected to the resistor R341. The second terminal of the operational amplifier U2 is connected to the second, fifteenth, tenth, and seventh terminals of the chip U9.

2. The operational amplifier circuit for automatic gear switching according to claim 1, characterized in that, The negative terminal of diode D211 is connected to a +5V voltage, and the positive terminal of diode D111 is grounded.

3. The operational amplifier circuit for automatic band switching according to claim 1, characterized in that, The chip U9 is an analog switch chip, and the fifth terminal of the chip U9 is grounded.

4. The operational amplifier circuit for automatic band switching according to claim 1, characterized in that, Both operational amplifier U1 and operational amplifier U2 are dual-channel operational amplifiers.

5. An operational amplifier circuit for automatic band switching according to claim 1, characterized in that, The ends of capacitors C111 and C131 furthest from the operational amplifier U1 are both grounded.

6. The operational amplifier circuit for automatic band switching according to claim 1, characterized in that, The end of resistor R341 furthest from operational amplifier U2 is grounded.

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