Opto-coupled isolated amplifier circuit

Abstract

The utility model discloses a kind of opto-coupler isolation amplification circuits, including first voltage stabilizing circuit, first amplifier circuit, second amplifier circuit, the input end of first voltage stabilizing circuit is used to obtain input signal, the output end of first voltage stabilizing circuit is connected the input end of first amplifier circuit, the output end of first amplifier circuit is connected the input end of second amplifier circuit, the output end of second amplifier circuit is used to output isolated amplification signal;First amplifier circuit is used to the input signal of first voltage stabilizing circuit output is amplified after opto-coupler isolation according to preset first amplification multiple, obtains first amplification signal;Second amplifier circuit is used to first amplification signal is amplified according to preset second amplification multiple, obtains isolated amplification signal.Solved the isolation chip of special use in traditional isolation circuit, this type of isolation chip has fixed gain multiple, signal isolation after output signal amplitude adjustment circuit is relatively complex, leading to the problem of higher cost of existing isolation circuit.

Description

Technical Field

[0001] This utility model relates to the field of signal isolation circuits, and in particular to an optocoupler isolation amplifier circuit. Background Technology

[0002] In circuit systems, to ensure safety and prevent electric shock, isolation circuits are needed to isolate the signals between high-voltage and low-voltage circuits. Similarly, to prevent interference between analog and digital signals and thus system instability, isolation is also required. Traditional isolation circuits use dedicated isolation chips, which have fixed gain ratios. This makes the circuit for adjusting the output signal amplitude after signal isolation relatively complex, resulting in high costs for existing isolation circuits. Summary of the Invention

[0003] This utility model provides an optocoupler isolation amplifier circuit to solve the problem that traditional isolation circuits use dedicated isolation chips. These types of isolation chips have fixed gain factors, and the adjustment circuit for the output signal amplitude after signal isolation is relatively complex, resulting in high costs for existing isolation circuits.

[0004] In one embodiment, an optocoupler-isolated amplifier circuit is provided, the optocoupler-isolated amplifier circuit comprising:

[0005] The circuit comprises a first voltage regulator circuit, a first amplifier circuit, and a second amplifier circuit. The input terminal of the first voltage regulator circuit is used to acquire an input signal. The output terminal of the first voltage regulator circuit is connected to the input terminal of the first amplifier circuit. The output terminal of the first amplifier circuit is connected to the input terminal of the second amplifier circuit. The output terminal of the second amplifier circuit is used to output an isolated amplified signal.

[0006] The first amplification circuit is used to amplify the input signal output by the first voltage regulator circuit after optocoupler isolation according to a preset first amplification factor, to obtain a first amplified signal; the second amplification circuit is used to amplify the first amplified signal according to a preset second amplification factor, to obtain the isolated amplified signal.

[0007] In one embodiment, the first amplifier circuit includes:

[0008] The circuit comprises a first operational amplifier, a first optocoupler, a second optocoupler, a first resistor, and a second resistor. The first input terminal of the first operational amplifier serves as the input terminal of the first amplifier circuit. The output terminal of the first operational amplifier is connected to the positive input terminal of the first optocoupler. The negative input terminal of the first optocoupler is connected to the positive input terminal of the second optocoupler. The negative input terminal of the second optocoupler is connected to ground. The positive output terminal of the first optocoupler is connected to a positive power supply. The negative output terminal of the first optocoupler is connected to one end of the first resistor. The other end of the resistor is connected to ground. The negative output terminal of the first optocoupler serves as the output terminal of the first amplifier circuit.

[0009] The positive output terminal of the second optocoupler is connected to the positive power supply, the negative output terminal of the second optocoupler is connected to one end of the second resistor and the second input terminal of the first operational amplifier, and the other end of the second resistor is connected to ground.

[0010] In one embodiment, the first amplification circuit further includes:

[0011] A third resistor and a first capacitor are connected, with the input of the third resistor connected to the output of the first operational amplifier and the output of the third resistor connected to the positive input of the first optocoupler isolator. One end of the first capacitor is connected to the output of the first operational amplifier, and the other end of the first capacitor is connected to the second input of the first operational amplifier.

[0012] In one embodiment, the second amplification circuit includes:

[0013] The second operational amplifier, the fourth resistor, and the fifth resistor are configured such that the first input terminal of the second operational amplifier serves as the input terminal of the second amplifier circuit, and the output terminal of the second operational amplifier serves as the output terminal of the second amplifier circuit; one end of the fourth resistor is connected to the output terminal of the second operational amplifier, the other end of the fourth resistor is connected to the second input terminal of the second operational amplifier and one end of the fifth resistor, and the other end of the fifth resistor is connected to ground.

[0014] In one embodiment, the first voltage regulator circuit includes:

[0015] A third operational amplifier and a first current-limiting resistor are connected. The first input terminal of the third operational amplifier is connected to the output terminal of the first current-limiting resistor, and the input terminal of the first current-limiting resistor serves as the input terminal of the first voltage regulator circuit. The output terminal of the third operational amplifier is connected to the second input terminal of the third operational amplifier.

[0016] In one embodiment, the optocoupler isolation amplifier circuit further includes:

[0017] The second current-limiting resistor has its input terminal connected to the output terminal of the first voltage regulator circuit, and its output terminal connected to the input terminal of the first amplifier circuit.

[0018] In one embodiment, the optocoupler isolation amplifier circuit further includes:

[0019] The second voltage regulator circuit has its input terminal connected to the output terminal of the second amplifier circuit, and its output terminal is used to output the isolated amplified signal after voltage regulation.

[0020] In one embodiment, the second voltage regulator circuit includes:

[0021] A fourth operational amplifier, wherein the first input terminal of the fourth operational amplifier serves as the input terminal of the second voltage regulator circuit, the output terminal of the fourth operational amplifier is connected to the second input terminal of the fourth operational amplifier, and the output terminal of the fourth operational amplifier serves as the output terminal of the second voltage regulator circuit.

[0022] In one embodiment, the optocoupler isolation amplifier circuit further includes:

[0023] A filtering circuit is provided, wherein the input terminal of the filtering circuit is connected to the output terminal of the second voltage regulator circuit, and the output terminal of the filtering circuit is used to output the filtered isolated amplified signal.

[0024] In one embodiment, the filtering circuit includes:

[0025] The filter includes a filter resistor and a filter capacitor. The input terminal of the filter resistor serves as the input terminal of the filter circuit. The output terminal of the filter resistor is connected to the input terminal of the filter capacitor. The output terminal of the filter capacitor is connected to ground, and the output terminal of the filter resistor serves as the output terminal of the filter circuit.

[0026] This utility model embodiment provides an optocoupler isolation amplifier circuit. By designing a first amplifier circuit and a second amplifier circuit, the regulated input signal is continuously amplified twice, and an isolated amplified signal is output with an overall amplification factor relative to the original input signal that is the product of the first amplification factor and the second amplification factor. Moreover, the gain factor can be designed according to the first amplification factor and the second amplification factor. Compared with existing isolation circuits, it saves the adjustment circuit of the output signal amplitude in the subsequent stage, and the whole circuit is simple, saving the cost of isolation circuits. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a circuit diagram of an optocoupler isolation amplifier according to one embodiment of the present invention;

[0029] The labeling is explained as follows:

[0030] 10. First voltage regulator circuit; 20. First amplifier circuit; 30. Second amplifier circuit; 40. Second voltage regulator circuit; 50. Filter circuit. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0032] It should be understood that this invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this invention to those skilled in the art. In the drawings, for clarity, the dimensions of layers and regions, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0033] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this utility model, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0034] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0036] To fully understand this utility model, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by this utility model. Preferred embodiments of this utility model are described in detail below; however, in addition to these detailed descriptions, this utility model may have other embodiments.

[0037] In one embodiment, such as Figure 1 As shown, an optocoupler-isolated amplifier circuit is provided, the optocoupler-isolated amplifier circuit comprising:

[0038] The circuit comprises a first voltage regulator circuit 10, a first amplifier circuit 20, and a second amplifier circuit 30. The input terminal of the first voltage regulator circuit 10 is used to acquire an input signal. The output terminal of the first voltage regulator circuit 10 is connected to the input terminal of the first amplifier circuit 20. The output terminal of the first amplifier circuit 20 is connected to the input terminal of the second amplifier circuit 30. The output terminal of the second amplifier circuit 30 is used to output an isolated amplified signal.

[0039] The first amplifier circuit 20 is used to amplify the input signal output by the first voltage regulator circuit 10 after optocoupler isolation according to a preset first amplification factor to obtain a first amplified signal; the second amplifier circuit 30 is used to amplify the first amplified signal according to a preset second amplification factor to obtain the isolated amplified signal.

[0040] The operation of the aforementioned optocoupler isolation amplifier circuit is as follows:

[0041] After the input signal is received at the input terminal of the first voltage regulator circuit 10, the first voltage regulator circuit 10 performs voltage regulation on the input signal to obtain a regulated input signal. The first amplifier circuit 20 amplifies the regulated input signal for the first time, with an amplification factor of a preset first amplification factor, to obtain a first amplified signal. The second amplifier circuit 30 amplifies the first amplified signal for the second time, with an amplification factor of a preset second amplification factor, to obtain an isolated amplified signal. The overall amplification factor of this isolated amplified signal relative to the original input signal is the product of the first amplification factor and the second amplification factor.

[0042] The optocoupler isolation amplifier circuit of this embodiment amplifies the regulated input signal twice through the designed first amplifier circuit 20 and second amplifier circuit 30, and outputs an isolated amplified signal with an overall amplification factor relative to the original input signal that is the product of the first amplification factor and the second amplification factor. The gain factor can be designed according to the first amplification factor and the second amplification factor. Compared with the existing isolation circuit, it saves the adjustment circuit of the output signal amplitude in the later stage, and the whole circuit is simple, saving the cost of the isolation circuit.

[0043] In one embodiment, such as Figure 1 As shown, the first amplifier circuit 20 includes:

[0044] The circuit consists of a first operational amplifier U1A, a first optocoupler U2, a second optocoupler U4, a first resistor R4, and a second resistor R7. The first input terminal of the first operational amplifier serves as the input terminal of the first amplifier circuit 20. The output terminal of the first operational amplifier is connected to the positive input terminal of the first optocoupler U2. The negative input terminal of the first optocoupler U2 is connected to the positive input terminal of the second optocoupler U4. The negative input terminal of the second optocoupler U4 is connected to ground. The positive output terminal of the first optocoupler U2 is connected to a positive power supply. The negative output terminal of the first optocoupler U4 is connected to one end of the first resistor, and the other end of the resistor is connected to ground. The negative output terminal of the first optocoupler U4 serves as the output terminal of the first amplifier circuit 20.

[0045] The positive output terminal of the second optocoupler is connected to the positive power supply, the negative output terminal of the second optocoupler is connected to one end of the second resistor and the second input terminal of the first operational amplifier, and the other end of the second resistor is connected to ground.

[0046] The operation of the first amplifier circuit 20 is as follows:

[0047] The first operational amplifier obtains a regulated input signal at its first input terminal. This input signal provides input current to the input terminals of the first and second optocouplers. The secondary supply voltage of both the first and second optocouplers is 12V. The first and second optocouplers generate collector currents in their secondary windings, respectively. The collector currents are proportional to the voltages generated by the first resistor R4 and the second resistor R7. That is, the input signal VIN is proportional to the voltage of the first amplified signal output through the first resistor R4. The amplification factor is a preset first amplification factor G1, and G1 = R4 / R7.

[0048] In one embodiment, such as Figure 1 As shown, the first amplifier circuit 20 further includes:

[0049] A third resistor R3 and a first capacitor C1 are connected. The input of the third resistor is connected to the output of the first operational amplifier, and the output of the third resistor is connected to the positive input of the first optocoupler. One end of the first capacitor is connected to the output of the first operational amplifier, and the other end of the first capacitor is connected to the second input of the first operational amplifier. The third resistor serves as a current limiter.

[0050] In one embodiment, such as Figure 1 As shown, the second amplifier circuit 30 includes:

[0051] The second operational amplifier U3A, the fourth resistor R5, and the fifth resistor R6 are connected together. The first input terminal of the second operational amplifier serves as the input terminal of the second amplifier circuit 30, and the output terminal of the second operational amplifier serves as the output terminal of the second amplifier circuit 30. One end of the fourth resistor is connected to the output terminal of the second operational amplifier, and the other end of the fourth resistor is connected to the second input terminal of the second operational amplifier and one end of the fifth resistor. The other end of the fifth resistor is connected to ground.

[0052] The operation of the second amplifier circuit 30 is as follows:

[0053] The first amplified signal is obtained from the first input terminal of the second operational amplifier. It is then amplified in phase by the second operational amplifier U3A, the fourth resistor R5 and the fifth resistor R6. The amplification factor is the preset second amplification factor G2, and G2 = 1 + R5 / R6, thus obtaining the isolated amplified signal.

[0054] In one embodiment, such as Figure 1 As shown, the first voltage regulator circuit 10 includes:

[0055] The third operational amplifier U1B and the first current-limiting resistor R1 are connected. The first input terminal of the third operational amplifier is connected to the output terminal of the first current-limiting resistor, and the input terminal of the first current-limiting resistor serves as the input terminal of the first voltage regulator circuit 10. The output terminal of the third operational amplifier is connected to the second input terminal of the third operational amplifier.

[0056] The first voltage regulator circuit 10 is used to regulate the input signal input to the first input terminal of the third operational amplifier.

[0057] In one embodiment, such as Figure 1 As shown, the optocoupler isolation amplifier circuit further includes:

[0058] The second current-limiting resistor R2 has its input terminal connected to the output terminal of the first voltage regulator circuit 10, and its output terminal connected to the input terminal of the first amplifier circuit 20.

[0059] The second current-limiting resistor is used to limit the current of the input signal input to the input terminal of the first amplifier circuit 20.

[0060] In one embodiment, such as Figure 1 As shown, the optocoupler isolation amplifier circuit further includes:

[0061] The second voltage regulator circuit 40 has its input terminal connected to the output terminal of the second amplifier circuit 30, and its output terminal is used to output the isolated amplified signal after voltage regulation.

[0062] The second voltage regulator circuit 40 is used to regulate the voltage of the isolated amplified signal output from the output terminal of the second amplifier circuit 30.

[0063] In one embodiment, such as Figure 1 As shown, the second voltage regulator circuit 40 includes:

[0064] The fourth operational amplifier (U3B) has its first input terminal serving as the input terminal of the second voltage regulator circuit 40, and its output terminal connected to its second input terminal, serving as the output terminal of the second voltage regulator circuit 40.

[0065] The fourth operational amplifier is used as a voltage follower to regulate the voltage of the isolated amplified signal output from the output terminal of the second amplifier circuit 30.

[0066] In one embodiment, such as Figure 1 As shown, the optocoupler isolation amplifier circuit further includes:

[0067] A filter circuit 50 is included, with its input connected to the output of the second voltage regulator circuit 40. The output of the filter circuit 50 is used to output the filtered isolated amplified signal. Specifically, the filter circuit 50 performs filtering processing on the isolated amplified signal.

[0068] In one embodiment, such as Figure 1 As shown, the filter circuit 50 includes:

[0069] The filter circuit 50 includes a filter resistor and a filter capacitor. The input terminal of the filter resistor serves as the input terminal of the filter circuit 50. The output terminal of the filter resistor is connected to the input terminal of the filter capacitor, and the output terminal of the filter capacitor is connected to ground. The output terminal of the filter resistor also serves as the output terminal of the filter circuit 50.

[0070] The ratio between the isolated amplified signal VOUT output from the output terminal of the filter circuit 50 and the input signal VIN is: VOUT=VIN*G1*G2, where G1 is the first amplification factor and G2 is the second amplification factor.

[0071] The optocoupler isolation amplifier circuit in this embodiment adopts a simple circuit structure and low-cost common optocoupler devices. Combining the characteristics of optocouplers and operational amplifiers, it realizes isolation amplification of the signal according to the total gain of the product of the first amplification factor and the second amplification factor, which greatly saves costs and improves the safety and stability of the circuit system.

[0072] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. An optically coupled isolated amplifier circuit, comprising: The optocoupler isolation amplifier circuit includes: The circuit comprises a first voltage regulator circuit, a first amplifier circuit, and a second amplifier circuit. The input terminal of the first voltage regulator circuit is used to acquire an input signal. The output terminal of the first voltage regulator circuit is connected to the input terminal of the first amplifier circuit. The output terminal of the first amplifier circuit is connected to the input terminal of the second amplifier circuit. The output terminal of the second amplifier circuit is used to output an isolated amplified signal. The first amplification circuit is used to amplify the input signal output by the first voltage regulator circuit after optocoupler isolation according to a preset first amplification factor, to obtain a first amplified signal; the second amplification circuit is used to amplify the first amplified signal according to a preset second amplification factor, to obtain the isolated amplified signal.

2. The optically coupled isolation amplifier circuit of claim 1, wherein, The first amplifier circuit includes: The circuit comprises a first operational amplifier, a first optocoupler, a second optocoupler, a first resistor, and a second resistor. The first input terminal of the first operational amplifier serves as the input terminal of the first amplifier circuit. The output terminal of the first operational amplifier is connected to the positive input terminal of the first optocoupler. The negative input terminal of the first optocoupler is connected to the positive input terminal of the second optocoupler. The negative input terminal of the second optocoupler is connected to ground. The positive output terminal of the first optocoupler is connected to a positive power supply. The negative output terminal of the first optocoupler is connected to one end of the first resistor. The other end of the resistor is connected to ground. The negative output terminal of the first optocoupler serves as the output terminal of the first amplifier circuit. The positive output terminal of the second optocoupler is connected to the positive power supply, the negative output terminal of the second optocoupler is connected to one end of the second resistor and the second input terminal of the first operational amplifier, and the other end of the second resistor is connected to ground.

3. The optically coupled isolation amplifier circuit of claim 2, wherein, The first amplifier circuit further includes: A third resistor and a first capacitor are connected, with the input of the third resistor connected to the output of the first operational amplifier and the output of the third resistor connected to the positive input of the first optocoupler isolator. One end of the first capacitor is connected to the output of the first operational amplifier, and the other end of the first capacitor is connected to the second input of the first operational amplifier.

4. The optically coupled isolation amplifier circuit of claim 1, wherein, The second amplifier circuit includes: The second operational amplifier, the fourth resistor, and the fifth resistor are configured such that the first input terminal of the second operational amplifier serves as the input terminal of the second amplifier circuit, and the output terminal of the second operational amplifier serves as the output terminal of the second amplifier circuit; one end of the fourth resistor is connected to the output terminal of the second operational amplifier, the other end of the fourth resistor is connected to the second input terminal of the second operational amplifier and one end of the fifth resistor, and the other end of the fifth resistor is connected to ground.

5. The optically coupled isolation amplifier circuit of claim 1, wherein, The first voltage regulator circuit includes: A third operational amplifier and a first current-limiting resistor are connected. The first input terminal of the third operational amplifier is connected to the output terminal of the first current-limiting resistor, and the input terminal of the first current-limiting resistor serves as the input terminal of the first voltage regulator circuit. The output terminal of the third operational amplifier is connected to the second input terminal of the third operational amplifier.

6. The optically coupled isolation amplifier circuit of claim 1, wherein, The optocoupler isolation amplifier circuit also includes: A second current-limiting resistor, an input end of the second current-limiting resistor being connected to an output end of the first voltage stabilizing circuit, and an output end of the second current-limiting resistor being connected to an input end of the first amplifying circuit.

7. The optically coupled isolation amplifier circuit of claim 1, wherein, The opto-coupler isolation amplifying circuit further comprises: A second voltage stabilizing circuit, an input end of the second voltage stabilizing circuit being connected to an output end of the second amplifying circuit, and an output end of the second voltage stabilizing circuit being used for outputting the isolation amplifying signal after voltage stabilization.

8. The optically coupled isolation amplifier circuit of claim 7, wherein, The second voltage stabilizing circuit comprises: A fourth operational amplifier, a first input end of the fourth operational amplifier being used as the input end of the second voltage stabilizing circuit, an output end of the fourth operational amplifier being connected to a second input end of the fourth operational amplifier, and the output end of the fourth operational amplifier being used as the output end of the second voltage stabilizing circuit.

9. The optically coupled isolation amplifier circuit of claim 7, wherein, The opto-coupler isolation amplifying circuit further comprises: A filter circuit, an input end of the filter circuit being connected to an output end of the second voltage stabilizing circuit, and an output end of the filter circuit being used for outputting the isolation amplifying signal after filtering.

10. The optically coupled isolation amplifier circuit of claim 9, wherein, The filter circuit comprises: A filter resistor and a filter capacitor, an input end of the filter resistor being used as the input end of the filter circuit, an output end of the filter resistor being connected to an input end of the filter capacitor, an output end of the filter capacitor being connected to the ground, and the output end of the filter resistor being used as the output end of the filter circuit.

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