A signal output circuit and an electric energy meter

Abstract

The utility model relates to intelligent electric energy meter technical field discloses a signal output circuit and electric energy meter, and the circuit includes: voltage stabilizing module, voltage amplification module, current conversion module and jumper, wherein, voltage stabilizing module's first end input control signal, voltage stabilizing module's second end is connected with voltage amplification module's first end, and current conversion module's first end connects ground after, voltage stabilizing module's third end is connected with voltage amplification module's second end, voltage amplification module's third end is connected with current conversion module's second end, and voltage amplification module's fourth end is connected with jumper's first input end, current conversion module's third end and fourth end are connected with jumper's second input end all. The utility model discloses through jumper module and can select output current signal or voltage signal, and jumper simple structure is high in reliability, configures in electric energy meter and can improve electric energy meter dynamic adaptability, realizes the flexible configuration of electric energy meter two parameter output functions with lower cost.

Description

Technical Field

[0001] This utility model relates to the field of smart energy meter technology, specifically to a signal output circuit and an energy meter. Background Technology

[0002] In the field of industrial smart instruments, using the PWM output of an MCU to generate analog signals through filtering is a common technique to reduce costs. The current technological level is as follows:

[0003] 1. Fixed-function PWM output modules: The most common existing technology is the single-function PWM transmitter module. For example, one module is designed and manufactured as a "PWM to 0-5V voltage output" module, and another module is fixed as a "PWM to 4-20mA current output" module. Users need to select one of them during procurement according to the requirements of the backend receiving equipment, and it cannot be changed once installed.

[0004] 2. Software-configurable output: Some more advanced solutions may use more complex circuitry on the module (such as a dedicated digital-to-analog converter (DAC) chip) combined with software, allowing users to switch output types via communication commands (such as Modbus). While flexible, this approach is more expensive, requires a DAC and more complex MCU logic, and its noise immunity and reliability may be inferior to pure hardware configurations in extreme industrial environments. Utility Model Content

[0005] In view of this, the present invention provides a signal output circuit and an energy meter to solve the problem of the limited types of output signals in existing energy meters.

[0006] In a first aspect, this utility model provides a signal output circuit, comprising: a voltage regulator module, a voltage amplifier module, a current conversion module, and a jumper. The first terminal of the voltage regulator module receives a control signal; the second terminal of the voltage regulator module is connected to and grounded after being connected to the first terminals of the voltage amplifier module and the current conversion module; the third terminal of the voltage regulator module is connected to the second terminal of the voltage amplifier module. The voltage regulator module is used to filter out interference in the control signal and output a stable voltage signal. The third terminal of the voltage amplifier module is connected to the second terminal of the current conversion module; the fourth terminal of the voltage amplifier module is connected to the first input terminal of the jumper. The voltage amplifier module is used to amplify the voltage signal. The third and fourth terminals of the current conversion module are both connected to the second input terminal of the jumper. The current conversion module is used to convert the voltage signal into a current signal. The jumper is used to selectively output the amplified voltage signal or the current signal.

[0007] The signal output circuit provided by this utility model allows for selective use of the fourth terminal of the voltage amplification module as the output terminal of the signal output circuit when a voltage device needs to be connected to the subsequent stage, outputting an amplified voltage signal. Conversely, when a current device needs to be connected to the subsequent stage, the jumper allows selective use of the third terminal of the current conversion module as the output terminal, outputting a current signal. The jumper can switch between different output signal types, improving the flexibility and adaptability of the signal output circuit. Furthermore, the jumper has a simple hardware structure, is unaffected by electromagnetic interference, and is easy to operate and low in cost.

[0008] In one optional embodiment, the voltage regulator module includes: a reference voltage generation unit, a first switching unit, and a filtering unit. A first terminal of the reference voltage generation unit is connected to a first terminal of the first switching unit; a second terminal of the reference voltage generation unit is connected to a second terminal of the first switching unit, a first terminal of the filtering unit, and a first terminal of the voltage amplification module; a third terminal of the reference voltage generation unit is connected to a third terminal of the first switching unit; and a fourth terminal of the reference voltage generation unit is connected to a second terminal of the filtering unit and a second terminal of the voltage amplification module. The reference voltage generation unit provides a reference voltage to the first switching unit. A control signal is input to the fourth terminal of the first switching unit, and the first switching unit modulates the control signal into a sine wave signal based on the reference voltage. The filtering unit filters out interference from the sine wave signal.

[0009] In one optional embodiment, the reference voltage generation unit includes: a reference source, a first resistor, a second resistor, a third resistor, and a first capacitor, wherein a first terminal of the reference source is connected to its second terminal, a first terminal of the first resistor, a first terminal of the third resistor, and a first terminal of the first capacitor; a third terminal of the reference source is connected to the second terminal of the first capacitor and a first terminal of a first switching unit; a second terminal of the first resistor is connected to the first terminal of the second resistor and a third terminal of the first switching unit; a second terminal of the second resistor is connected to the second terminal of a filtering unit; and an external reference voltage is input to the second terminal of the third resistor.

[0010] In one optional embodiment, the first switching unit includes: a fourth resistor, a fifth resistor, a first switch, and a second switch, wherein the first end of the fourth resistor is connected to the first end of the fifth resistor and the first end of the reference voltage generating unit; the second end of the fourth resistor is connected to the control end of the first switch and receives a control signal; the second end of the fifth resistor is connected to the first end of the first switch and the control end of the second switch; the second end of the first switch is connected to the first end of the second switch and the second end of the reference voltage generating unit; and the second end of the second switch is connected to the third end of the reference voltage generating unit.

[0011] In one optional embodiment, the voltage amplification module includes: a diode, a sixth resistor, a seventh resistor, and a first operational amplifier, wherein the anode of the diode is connected to the third terminal of the voltage regulator module and the non-inverting input terminal of the first operational amplifier, and the cathode of the diode is connected to the second terminal of the current conversion module; the first terminal of the sixth resistor is connected to the first terminal of the seventh resistor and the inverting input terminal of the first operational amplifier, and the second terminal of the sixth resistor is grounded; the second terminal of the seventh resistor is connected to the output terminal of the first operational amplifier and the first input terminal of the jumper; the first power supply terminal of the first operational amplifier receives an external reference voltage, and the second power supply terminal of the first operational amplifier is grounded.

[0012] In one optional embodiment, the current conversion module includes: an amplification unit and a second switching unit, wherein a first terminal of the amplification unit is connected to a third terminal of the voltage amplification module, a second terminal and a third terminal of the amplification unit are respectively connected to a control terminal and a first terminal of the second switching unit, a fourth terminal of the amplification unit is connected to a second terminal of the second switching unit and a second input terminal of a jumper; and an external reference voltage is input to the third terminal of the second switching unit.

[0013] In one optional embodiment, the amplification unit includes: a second operational amplifier, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor, wherein the first terminal of the eighth resistor is connected to the third terminal of the voltage amplification module, and the second terminal of the eighth resistor is connected to the first terminal of the eleventh resistor and the non-inverting input terminal of the second operational amplifier; the first terminal of the ninth resistor is connected to the control terminal of the second switching unit, and the second terminal of the ninth resistor is connected to the output terminal of the second operational amplifier; the first terminal of the tenth resistor is connected to the inverting input terminal of the second operational amplifier and the first terminal of the second switching unit, and the second terminal of the tenth resistor is grounded; the second terminal of the eleventh resistor is connected to the second input terminal of the jumper.

[0014] In one optional embodiment, the second switching unit includes: a twelfth resistor, a thirteenth resistor, and a third switch, wherein the first end of the twelfth resistor is connected to the third end of the amplification unit, the second end of the twelfth resistor is connected to the first end of the third switch and the first end of the thirteenth resistor; the control end of the third switch is connected to the second end of the amplification unit, and the second end of the third switch is input with an external reference voltage; the second end of the thirteenth resistor is connected to the second input end of the jumper.

[0015] In one optional embodiment, the signal output circuit further includes an isolation module, wherein the input terminal of the isolation module receives a control signal, and the first and second output terminals of the isolation module are respectively connected to the first and second terminals of the voltage regulator module, and the isolation module is used to isolate the control signal.

[0016] Secondly, this utility model provides an energy meter, including the signal output circuit of the first aspect or any corresponding embodiment described above. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a diagram illustrating the composition of the signal output circuit according to an embodiment of the present invention;

[0019] Figure 2 This is a detailed circuit diagram of the signal output circuit according to an embodiment of the present utility model;

[0020] Figure 3 This is another specific circuit diagram of the signal output circuit according to an embodiment of the present utility model. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and 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, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a simple connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0024] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0025] This embodiment provides a signal output circuit, such as Figure 1 As shown, it includes: voltage regulator module 1, voltage amplifier module 2, current conversion module 3, and jumper 4.

[0026] Figure 1 In the process, the first terminal of the voltage regulator module 1 receives the control signal, the second terminal of the voltage regulator module 1 is connected to the first terminal of the voltage amplifier module 2 and the first terminal of the current conversion module 3 and then grounded, and the third terminal of the voltage regulator module 1 is connected to the second terminal of the voltage amplifier module 2.

[0027] Optionally, the voltage regulator module is used to filter out interference in the control signal and output a stable voltage signal. The control signal can be a PWM signal, and the voltage regulator module filters out interference in the PWM signal and outputs a smooth voltage signal.

[0028] Figure 1 In the middle, the third terminal of the voltage amplification module 2 is connected to the second terminal of the current conversion module 3, and the fourth terminal of the voltage amplification module 2 is connected to the first input terminal of the jumper 4;

[0029] Specifically, the voltage amplification module is used to amplify and buffer the regulated voltage signal, adjust the signal amplitude or realize specific voltage calculation relationships, and play the role of buffering and impedance transformation. It can improve the level of the voltage signal output by the voltage regulator module and output a stable amplified voltage signal with strong load-carrying capacity.

[0030] Figure 1 In the process, the third and fourth terminals of the current conversion module 3 are both connected to the second input terminal of the jumper 4. The current conversion module 3 is used to convert the voltage signal into a current signal.

[0031] Figure 1 In this circuit, jumper 4 is used to selectively output the amplified voltage signal or current signal.

[0032] Specifically, by changing the connection relationship between the two input terminals and the output terminal of jumper 4, the path of the subsequent circuit is switched, thereby allowing the circuit to ultimately output a voltage signal or a current signal. When the subsequent circuit of the signal output circuit is connected to a voltage device, the user only needs to connect the output terminal of the jumper to the first input terminal of the jumper to output the amplified voltage signal; similarly, when the subsequent circuit of the signal output circuit is connected to a current device, the user only needs to connect the output terminal of the jumper to the second input terminal of the jumper to output the current signal. When replacing the subsequent circuit, there is no need to replace the components in the signal output circuit; simply flipping the jumper quickly changes the output mode, simplifying operation and streamlining debugging and maintenance.

[0033] Alternatively, the jumper can also be a switch with a simple hardware structure, such as a DIP switch.

[0034] The signal output circuit provided in this embodiment allows the jumper to selectively use the fourth terminal of the voltage amplification module as the output terminal of the signal output circuit when a voltage device needs to be connected to the subsequent stage of the signal output circuit, outputting an amplified voltage signal. Conversely, when a current device needs to be connected to the subsequent stage of the signal output circuit, the jumper can selectively use the third terminal of the current conversion module as the output terminal of the signal output circuit, outputting a current signal. The jumper can switch between different types of output signals, improving the flexibility and adaptability of the signal output circuit. Furthermore, the jumper has a simple hardware structure, is unaffected by electromagnetic interference, and is easy to operate and low in cost.

[0035] In some alternative implementations, such as Figure 2 As shown, the voltage regulator module 1 includes: a reference voltage generation unit 11, a first switching unit 12, and a filtering unit 13. The first terminal of the reference voltage generation unit 11 is connected to the first terminal of the first switching unit 12; the second terminal of the reference voltage generation unit 11 is connected to the second terminal of the first switching unit 12, the first terminal of the filtering unit 13, and the first terminal of the voltage amplification module 2; the third terminal of the reference voltage generation unit 11 is connected to the third terminal of the first switching unit 12; and the fourth terminal of the reference voltage generation unit 11 is connected to the second terminal of the filtering unit 13 and the second terminal of the voltage amplification module 2. The reference voltage generation unit 11 provides a reference voltage to the first switching unit 12. A control signal is input to the fourth terminal of the first switching unit 12, and the first switching unit 12 modulates the control signal into a sine wave signal based on the reference voltage. The filtering unit 13 filters out interference from the sine wave signal.

[0036] Specifically, Figure 2In this embodiment, the reference voltage generation unit 11 includes: a reference source U1, a first resistor R1, a second resistor R2, a third resistor R9, and a first capacitor C1. The first terminal of the reference source U1 is connected to its second terminal, the first terminal of the first resistor R1, the first terminal of the third resistor R9, and the first terminal of the first capacitor C1. The third terminal of the reference source U1 is connected to the second terminal of the first capacitor C1 and the first terminal of the first switching unit 12. The second terminal of the first resistor R1 is connected to the first terminal of the second resistor R2 and the third terminal of the first switching unit 12. The second terminal of the second resistor R2 is connected to the second terminal of the filtering unit 13. The second terminal of the third resistor R9 receives an external reference voltage. In this embodiment, the external reference voltage is 12V.

[0037] Specifically, Figure 2 In the middle, the reference source U1 is a CJ431 precision voltage reference chip, which can provide a stable reference voltage. The filter unit 13 includes a filter capacitor C2, which is used to filter out high-frequency noise in the signal and make the signal more stable.

[0038] Specifically, Figure 2 In the first switching unit 12, there are: a fourth resistor R6, a fifth resistor R7, a first switch Q1, and a second switch Q2. The first end of the fourth resistor R6 is connected to the first end of the fifth resistor R7 and the first end of the reference voltage generating unit 11. The second end of the fourth resistor R6 is connected to the control end of the first switch Q1 and receives a control signal. The second end of the fifth resistor R7 is connected to the first end of the first switch Q1 and the control end of the second switch Q2. The second end of the first switch Q1 is connected to the first end of the second switch Q2 and the second end of the reference voltage generating unit 11. The second end of the second switch Q2 is connected to the third end of the reference voltage generating unit 11.

[0039] For example, Figure 2 In this circuit, when the control signal is a PWM signal, the reference source U1 first generates a stable 2.5V voltage. The PWM signal controls the first switch Q1; when the level is high, the first switch Q1 is off, and vice versa. The collector of the first switch Q1 then controls the second switch Q2. The two switches modulate the input PWM waveform into a sine wave with a level of 0–2.5V. Finally, the signal is modulated by the filter capacitor C2 into a smooth and controllable voltage signal; for example, 0% duty cycle corresponds to 0V, and 100% duty cycle corresponds to 2.5V. When the output voltage signal deviates from the reference, the conduction level of the second switch Q2 changes, thereby adjusting the current or voltage distribution of the circuit to achieve regulated output.

[0040] In some alternative implementations, such as Figure 3As shown, the voltage amplification module 2 includes: diode D1, sixth resistor R4, seventh resistor R3, and first operational amplifier U3.1. The anode of diode D1 is connected to the third terminal of voltage regulator module 1 and the non-inverting input terminal of first operational amplifier U3.1, and the cathode of diode D1 is connected to the second terminal of current conversion module 3. The first terminal of sixth resistor R4 is connected to the first terminal of seventh resistor R3 and the inverting input terminal of first operational amplifier U3.1, and the second terminal of sixth resistor R4 is grounded. The second terminal of seventh resistor R3 is connected to the output terminal of first operational amplifier U3.1 and the first input terminal of jumper 4. The first power supply terminal of first operational amplifier U3.1 receives an external reference voltage, and the second power supply terminal of first operational amplifier U3.1 is grounded.

[0041] Specifically, Figure 3 In the circuit, the first operational amplifier U3.1 is configured as an amplifier circuit through the external sixth resistor R4 and seventh resistor R3; the diode D1 is used for unidirectional limiting to prevent the first operational amplifier U3.1 from being damaged by overvoltage.

[0042] In some alternative implementations, such as Figure 3 As shown, the current conversion module 3 includes an amplification unit 31 and a second switching unit 32. The first end of the amplification unit 31 is connected to the third end of the voltage amplification module 2. The second and third ends of the amplification unit 31 are respectively connected to the control end and the first end of the second switching unit 32. The fourth end of the amplification unit 31 is connected to the second end of the second switching unit 32 and the second input end of the jumper 4. An external reference voltage is input to the third end of the second switching unit 32.

[0043] Specifically, Figure 3 In the amplifier unit 31, there are: a second operational amplifier U3.2, an eighth resistor R8, a ninth resistor R10, a tenth resistor R14, and an eleventh resistor R15. The first end of the eighth resistor R8 is connected to the third end of the voltage amplification module 2, and the second end of the eighth resistor R8 is connected to the first end of the eleventh resistor R15 and the non-inverting input of the second operational amplifier U3.2. The first end of the ninth resistor R10 is connected to the control end of the second switching unit 32, and the second end of the ninth resistor R10 is connected to the output end of the second operational amplifier U3.2. The first end of the tenth resistor R14 is connected to the inverting input of the second operational amplifier U3.2 and the first end of the second switching unit 32, and the second end of the tenth resistor R14 is grounded. The second end of the eleventh resistor R15 is connected to the second input end of the jumper 4.

[0044] Specifically, Figure 3In the second switching unit 32, there are: a twelfth resistor R12, a thirteenth resistor R13, and a third switch Q3. The first end of the twelfth resistor R12 is connected to the third end of the amplification unit 31, and the second end of the twelfth resistor R12 is connected to the first end of the third switch Q3 and the first end of the thirteenth resistor R13. The control end of the third switch Q3 is connected to the second end of the amplification unit 31, and the second end of the third switch Q3 is input with an external reference voltage. The second end of the thirteenth resistor R13 is connected to the second input end of the jumper 4.

[0045] For example, Figure 3 In the circuit, the voltage signal, after being regulated and amplified by the pre-amplifier, is input to the non-inverting input of the second operational amplifier U3.2 as a conversion reference. The second operational amplifier U3.2 linearly converts this voltage signal into a 4-20mA current output. The output signal of the second operational amplifier U3.2 controls the base current of the third switch Q3, adjusting the conduction level of the third switch Q3: when the input voltage increases, the conduction of the third switch Q3 increases, and the current flowing from the +12V power supply to jumper 4 increases; conversely, the current decreases, ultimately achieving a linear correspondence between the output current and the input voltage. The third switch Q3 also isolates the second operational amplifier U3.2 and shares power, allowing the second operational amplifier U3.2 to significantly improve the circuit's output current and power drive capability without sacrificing control accuracy.

[0046] In some alternative implementations, such as Figure 2 As shown, the signal output circuit also includes an isolation module 5, wherein the input terminal of the isolation module 5 receives the control signal, and the first and second output terminals of the isolation module 5 are respectively connected to the first and second terminals of the voltage regulator module 1. The isolation module 5 is used to isolate the control signal.

[0047] For example, Figure 2 In the middle, isolation module 5 includes a current-limiting resistor R16 and an optocoupler U2. The first switch Q1 and the second switch Q2 are used to modulate the PWM square wave whose level is disordered due to optocoupler isolation.

[0048] This embodiment provides an energy meter, including the signal output circuit of the above embodiment or any corresponding implementation thereof.

[0049] The energy meter provided in this embodiment allows for selective switching of the fourth terminal of the voltage amplification module as the output terminal of the signal output circuit when a voltage device needs to be connected to the subsequent stage of the signal output circuit, outputting an amplified voltage signal. Conversely, when a current device needs to be connected to the subsequent stage of the signal output circuit, the jumper allows for selective switching of the third terminal of the current conversion module as the output terminal of the signal output circuit, outputting a current signal. The jumper can switch between different types of output signals, improving the flexibility and adaptability of the signal output circuit. Furthermore, the jumper has a simple hardware structure, is unaffected by electromagnetic interference, and is easy to operate and low in cost.

[0050] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A signal output circuit, characterized in that, include: The system includes a voltage regulator module, a voltage amplifier module, a current conversion module, and jumpers. The first terminal of the voltage regulator module receives a control signal, the second terminal of the voltage regulator module is connected to the first terminal of the voltage amplifier module and the first terminal of the current conversion module and then grounded, and the third terminal of the voltage regulator module is connected to the second terminal of the voltage amplifier module. The voltage regulator module is used to filter out interference in the control signal and output a stable voltage signal. The third terminal of the voltage amplification module is connected to the second terminal of the current conversion module, and the fourth terminal of the voltage amplification module is connected to the first input terminal of the jumper. The voltage amplification module is used to amplify the voltage signal. The third and fourth terminals of the current conversion module are both connected to the second input terminal of the jumper, and the current conversion module is used to convert the voltage signal into a current signal. The jumper is used to selectively output the amplified voltage signal or the current signal.

2. The signal output circuit according to claim 1, characterized in that, The voltage regulation module includes: a reference voltage generation unit, a first switching unit, and a filtering unit, wherein... The first terminal of the reference voltage generation unit is connected to the first terminal of the first switching unit, the second terminal of the reference voltage generation unit is connected to the second terminal of the first switching unit, the first terminal of the filtering unit and the first terminal of the voltage amplification module, the third terminal of the reference voltage generation unit is connected to the third terminal of the first switching unit, and the fourth terminal of the reference voltage generation unit is connected to the second terminal of the filtering unit and the second terminal of the voltage amplification module. The reference voltage generation unit is used to provide a reference voltage for the first switching unit. The fourth terminal of the first switching unit receives a control signal, and the first switching unit is used to modulate the control signal into a sine wave signal based on the reference voltage; The filtering unit is used to filter out interference in the sine wave signal.

3. The signal output circuit according to claim 2, characterized in that, The reference voltage generation unit includes: a reference source, a first resistor, a second resistor, a third resistor, and a first capacitor, wherein, The first end of the reference source is connected to its second end, the first end of the first resistor, the first end of the third resistor, and the first end of the first capacitor; the third end of the reference source is connected to the second end of the first capacitor and the first end of the first switching unit. The second end of the first resistor is connected to the first end of the second resistor and the third end of the first switching unit; The second terminal of the second resistor is connected to the second terminal of the filter unit; The second terminal of the third resistor is input with an external reference voltage.

4. The signal output circuit according to claim 2, characterized in that, The first switching unit includes: a fourth resistor, a fifth resistor, a first switch, and a second switch, wherein, The first end of the fourth resistor is connected to the first end of the fifth resistor and the first end of the reference voltage generating unit, and the second end of the fourth resistor is connected to the control end of the first switch and receives control signals. The second end of the fifth resistor is connected to the first end of the first switch and the control end of the second switch; The second terminal of the first switch is connected to the first terminal of the second switch and the second terminal of the reference voltage generating unit; The second terminal of the second switch is connected to the third terminal of the reference voltage generation unit.

5. The signal output circuit according to claim 1, characterized in that, The voltage amplification module includes: a diode, a sixth resistor, a seventh resistor, and a first operational amplifier, wherein, The anode of the diode is connected to the third terminal of the voltage regulator module and the non-inverting input terminal of the first operational amplifier, and the cathode of the diode is connected to the second terminal of the current conversion module. The first end of the sixth resistor is connected to the first end of the seventh resistor and the inverting input of the first operational amplifier, and the second end of the sixth resistor is grounded. The second end of the seventh resistor is connected to the output end of the first operational amplifier and the first input end of the jumper; An external reference voltage is input to the first power supply terminal of the first operational amplifier, and the second power supply terminal of the first operational amplifier is grounded.

6. The signal output circuit according to claim 1, characterized in that, The current conversion module includes: an amplification unit and a second switching unit, wherein... The first end of the amplification unit is connected to the third end of the voltage amplification module, the second and third ends of the amplification unit are respectively connected to the control end and the first end of the second switching unit, and the fourth end of the amplification unit is connected to the second end of the second switching unit and the second input end of the jumper. An external reference voltage is input to the third terminal of the second switching unit.

7. The signal output circuit according to claim 6, characterized in that, The amplification unit includes: a second operational amplifier, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor, wherein, The first end of the eighth resistor is connected to the third end of the voltage amplification module, and the second end of the eighth resistor is connected to the first end of the eleventh resistor and the non-inverting input of the second operational amplifier. The first end of the ninth resistor is connected to the control terminal of the second switching unit, and the second end of the ninth resistor is connected to the output terminal of the second operational amplifier. The first end of the tenth resistor is connected to the inverting input of the second operational amplifier and the first end of the second switching unit, and the second end of the tenth resistor is grounded. The second end of the eleventh resistor is connected to the second input end of the jumper.

8. The signal output circuit according to claim 6, characterized in that, The second switching unit includes: a twelfth resistor, a thirteenth resistor, and a third switch, wherein, The first end of the twelfth resistor is connected to the third end of the amplification unit, and the second end of the twelfth resistor is connected to the first end of the third switch and the first end of the thirteenth resistor. The control terminal of the third switch is connected to the second terminal of the amplification unit, and the second terminal of the third switch is input with an external reference voltage. The second end of the thirteenth resistor is connected to the second input end of the jumper.

9. The signal output circuit according to claim 1, characterized in that, Also includes: Isolation module, in which, The isolation module receives a control signal at its input terminal, and its first and second output terminals are respectively connected to the first and second terminals of the voltage regulator module. The isolation module is used to isolate the control signal.

10. An electricity meter, characterized in that, Includes the signal output circuit as described in any one of claims 1 to 9.

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