Sampling and metering circuit and corresponding circuit board

Abstract

The utility model provides a sampling metering circuit and a corresponding circuit board. A voltage conversion module receives sampling analog signals output by a sampling module. The voltage conversion module can perform voltage conversion on the high-voltage sampling analog signal to generate a low-voltage sampling analog signal. The current conversion module receives the sampling analog signal output by the sampling module, and the current conversion module can perform current conversion on the high-current sampling analog signal to generate a low-current sampling analog signal. The metering module is connected with the voltage conversion module and the current conversion module. The metering module receives the low-voltage sampling analog signal and the low-current sampling analog signal. The metering module can perform analog-to-digital conversion on the low-voltage sampling analog signal and the low-current sampling analog signal to generate a digital signal. The microcontroller module is connected with the metering module and receives the digital signal. And the microcontroller module can perform data processing on the digital signal and store a data processing result in a data memory of the microcontroller module.

Description

TECHNICAL FIELD

[0001] The utility model relates to circuit technical field, especially a kind of sampling measurement circuit and corresponding circuit board. BACKGROUND

[0002] In the operation monitoring of power system, fault diagnosis and the development and testing process of power equipment, it is crucial to accurately obtain the voltage and current of signal. However, there is a great security risk in high-voltage and high-current environment. Direct sampling can damage the sampling circuit, and even cause damage to the measuring equipment and the operator, such as electrical breakdown and overcurrent damage. Therefore, the existing sampling circuit is easily damaged by high voltage or high current.

[0003] Therefore, it is necessary to provide a sampling measurement circuit and corresponding circuit board to solve the above technical problems. SUMMARY

[0004] The utility model provides a kind of sampling measurement circuit and corresponding circuit board, effectively solve the technical problem that existing sampling circuit is easily damaged by high voltage or high current.

[0005] The utility model provides a kind of sampling measurement circuit, it includes:

[0006] Voltage conversion module, which receives the sampling analog signal output by the sampling module, is used for voltage conversion operation on the high-voltage sampling analog signal to generate low-voltage sampling analog signal, and the voltage conversion module includes an isolation unit, which is used to isolate the interference generated by the ground line to the low-voltage sampling analog signal;

[0007] Current conversion module, which receives the sampling analog signal output by the sampling module, is used for current conversion operation on the high-current sampling analog signal to generate low-current sampling analog signal;

[0008] Measurement module, connected to the voltage conversion module and the current conversion module respectively, receives low-voltage sampling analog signal and low-current sampling analog signal, and is used for analog-to-digital conversion operation on low-voltage sampling analog signal and low-current sampling analog signal to generate digital signal;

[0009] Microcontroller module, connected to the measurement module, receives the digital signal, and is used for data processing operation on the digital signal, and saves the result of data processing in its data storage.

[0010] Further, the metering module comprises an integrated metering chip, the integrated metering chip comprises a first input pin, a second input pin and an output pin, the first input pin is connected with the voltage conversion module, and the first input pin is used for receiving the sampled analog signal with low voltage; the second input pin is connected with the voltage conversion module, and the second input pin is used for receiving the sampled analog signal with low current;

[0011] The integrated metering chip is used for performing an analog-to-digital conversion operation on the sampled analog signal with low voltage and the sampled analog signal with low current, to generate a digital signal; and the output pin is connected with the microcontroller module, and the output pin is used for outputting the digital signal.

[0012] Further, the voltage conversion module comprises a voltage dividing unit, one end of the voltage dividing unit is connected with the sampling module, and the other end of the voltage dividing unit is connected with the isolation unit, and the voltage dividing unit is used for performing a voltage conversion operation on the sampled analog signal with high voltage, to generate the sampled analog signal with low voltage.

[0013] Further, the voltage conversion module comprises an operational amplifier unit, one end of the operational amplifier unit is connected with the isolation unit, and the other end of the operational amplifier unit is connected with the first input pin, and the operational amplifier unit is used for performing a signal amplification operation on the sampled analog signal with low voltage.

[0014] Further, the current conversion module comprises a current transformer unit, one end of the current transformer unit is connected with the sampling module, and the other end of the current transformer unit is connected with the second input pin, and the current transformer unit is used for performing a current conversion operation on the sampled analog signal with high current, to generate the sampled analog signal with low current.

[0015] Further, the current conversion module comprises an anti-interference unit, one end of the anti-interference unit is connected with the current transformer unit, and the other end of the anti-interference unit is connected with the second input pin, and the anti-interference unit is used for inhibiting interference generated by group pulses on the sampled analog signal with low current.

[0016] Further, the current conversion module comprises a filtering unit, one end of the filtering unit is connected with the anti-interference unit, and the other end of the anti-interference unit is connected with the second input pin, and the filtering unit is used for performing a filtering operation on the sampled analog signal with low current.

[0017] Further, the metering module includes the power supply unit, the integrated metering chip includes an analog power supply pin and a digital power supply pin, the power supply unit is connected to the analog power supply pin and the digital power supply pin, and the power supply unit is used to output a power supply voltage for power supply operation of the integrated metering chip.

[0018] A circuit board comprising the sampling metering circuit of any of the preceding claims.

[0019] Compared with the prior art, the sampling metering circuit has the beneficial effects that: the sampling metering circuit includes a voltage conversion module, a current conversion module, a metering module, and a microcontroller module. The voltage conversion module can convert the high-voltage sampling analog signal to generate a low-voltage sampling analog signal. The current conversion module can convert the high-current sampling analog signal to generate a low-current sampling analog signal. Therefore, the sampling analog signal can be converted into a low-voltage and low-current signal after passing through the voltage conversion module and the current conversion module. Further, the metering module can safely perform analog-to-digital conversion on the low-voltage sampling analog signal and the low-current sampling analog signal to generate a digital signal. The microcontroller module can also safely perform data processing on the digital signal and save the result of the data processing in its data storage. The voltage conversion module and the current conversion module effectively protect the metering module and the microcontroller module, and can avoid damage to the metering module and the microcontroller module caused by high voltage and large current. The technical problem that the existing sampling circuit is easily damaged by high voltage or large current is effectively solved. The sampling metering circuit provided with the voltage conversion module and the current conversion module is also beneficial to avoid damage to the measuring equipment and the operator caused by electrical breakdown and overcurrent. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following briefly introduces the drawings needed in the embodiments. The drawings in the following description are only corresponding drawings of some embodiments of the present application.

[0021] Figure 1 A block diagram of an embodiment of the sampling metering circuit of the present application.

[0022] Figure 2 A circuit diagram of the voltage conversion module of an embodiment of the sampling metering circuit of the present application.

[0023] Figure 3 A circuit diagram of the current conversion module and the metering module of an embodiment of the sampling metering circuit of the present application.

[0024] Figure 4 A circuit diagram of the connection module of an embodiment of the sampling metering circuit of the present application.

[0025] Figure 5 The circuit diagram of the power supply unit of the sampling metering circuit embodiment of the utility model.

[0026] In the figure, 10, sampling metering circuit;11, voltage conversion module;111, voltage division unit;112, isolation unit;113, operational amplifier unit;12, current conversion module;121, current transformer unit;122, anti-interference unit;123, filter unit;13, metering module;131, power supply unit;14, microcontroller module;15, connection module;151, first connection unit;1511, input end of the first connection unit;152, second connection unit;1521, input end of the second connection unit;153, third connection unit;1531, input end of the third connection unit;16, sampling module. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0028] The direction terms mentioned in the utility model, such as "up", "down", "front", "back", "left", "right", "inside", "outside", "side", "top" and "bottom", are only the orientation of the drawings, and the direction terms are used to explain and understand the utility model, and not to limit the utility model.

[0029] The terms "first", "second" and the like in the utility model are only for the purpose of description, and cannot be understood as indicating or implying relative importance, and are not limited as the order of precedence.

[0030] In the figure, the units with similar structures are denoted by the same reference numerals.

[0031] Please refer to Figure 1The utility model provides a kind of sampling measurement circuit 10.The sampling measurement circuit 10 is applied to a kind of circuit board, the circuit board can be set in a three-phase intelligent electric meter, the sampling measurement circuit 10 includes voltage conversion module 11, current conversion module 12, measurement module 13 and microcontroller module 14.Voltage conversion module 11 receives the sampling analog signal output by sampling module 16, voltage conversion module 11 is used to carry out voltage conversion operation to the sampling analog signal of high voltage, and voltage conversion module 11 can generate the sampling analog signal of low voltage.Current conversion module 12 receives the sampling analog signal output by sampling module 16, and current conversion module 12 is used to carry out current conversion operation to the sampling analog signal of high current, and current conversion module 12 can generate the sampling analog signal of low current.Measurement module 13 is connected with voltage conversion module 11 and current conversion module 12 respectively, and measurement module 13 receives the sampling analog signal of low voltage and the sampling analog signal of low current.Measurement module 13 is used to carry out analog-digital conversion operation to the sampling analog signal of low voltage and the sampling analog signal of low current, and measurement module 13 can generate digital signal.Microcontroller module 14 is connected with measurement module 13, and microcontroller module 14 receives digital signal.Microcontroller module 14 is used for digital signal to carry out data processing operation, and microcontroller module 14 saves the result of data processing in its data memory.Moreover, microcontroller module 14 can provide information to external interface at any time, and microcontroller module 14 can carry out data exchange with external interface.

[0032] Please refer to Figures 1 to 5 The specific circuit structure of sampling measurement circuit 10 is described in detail as follows:

[0033] Please refer to Figure 2 And Figure 3The metering module 13 comprises an integrated metering chip U100, which is ADE9000. The integrated metering chip U100 comprises a first input pin, a second input pin and an output pin. The first input pin is connected to the voltage conversion module 11 and is used to receive the low-voltage sampling analog signal. The first input pin comprises a first input pin V1N, a first input pin V1P, a first input pin V2N, a first input pin V2P, a first input pin V3N and a first input pin V3P. The second input pin is connected to the voltage conversion module 11 and is used to receive the low-current sampling analog signal. The second input pin comprises a second input pin I1N, a second input pin I1P, a second input pin I2N, a second input pin I2P, a second input pin I3N, a second input pin I3P, a second input pin I4N and a second input pin I4P. The integrated metering chip U100 is used to perform an analog-to-digital conversion operation on the low-voltage sampling analog signal and the low-current sampling analog signal, and the integrated metering chip U100 can generate a digital signal. The output pin is connected to the microcontroller module 14 and is used to output the digital signal. The output pin comprises an output pin CF1, an output pin CF2, an output pin CF3 and an output pin CF4.

[0034] Please refer to Figure 2 The voltage conversion module 11 comprises a voltage division unit 111. One end of the voltage division unit 111 is connected to the sampling module 16, and the other end of the voltage division unit 111 is connected to the isolation unit 112. The voltage division unit 111 is used to perform a voltage conversion operation on the high-voltage sampling analog signal, and the voltage division unit 111 can generate a low-voltage sampling analog signal. The voltage of the sampling analog signal is a three-phase alternating voltage, and after being divided by the voltage division unit 111, the voltage of the sampling analog signal can be reduced to about 0-600mv. The voltage division unit 111 comprises a voltage division resistor, which comprises voltage division resistors R11, R12, R13, R14, R15, R21, R22, R23, R24, R25, R31, R32, R33, R34, R35, R41, R42, R43, R44 and R45. The resistance value of the voltage division resistor is 27KΩ.

[0035] Please refer to Figure 2The voltage conversion module 11 comprises an isolation unit 112, which is used to isolate the interference of the ground to the low-voltage sampling analog signal. At the same time, the isolation unit 112 can isolate the digital ground between the 220V ground and the metering chip. In addition, the isolation unit 112 comprises an operational amplifier U1A, an operational amplifier U3A, an operational amplifier U5A, and an operational amplifier U7A. The operational amplifier can resist external interference signals, effectively enhancing the stability and reliability of the circuit.

[0036] In the prior art, a sampling voltage transformer or an isolation chip is generally used to isolate the sampling analog signal. However, the sampling voltage transformer or the isolation chip has the disadvantages of large size and high cost. However, the isolation unit 112 of the present scheme is provided with an operational amplifier. The operational amplifier can isolate the ground of the metering chip U100 from the high voltage (220V or above) ground, so that the strong voltage will not break through the chip. In addition, compared with the sampling voltage transformer or the isolation chip, the operational amplifier has low cost and small size. It is beneficial to integrate the circuit into a chip or a circuit board, and can effectively save the cost of circuit design and manufacturing.

[0037] In addition, the large isolation unit 112 of the present scheme can adjust the parameters of the sampling signal, so as to change the size of the signal and enhance the resistance to noise.

[0038] Please refer to Figure 2 The voltage conversion module 11 comprises an operational amplification unit 113. One end of the operational amplification unit 113 is connected to the isolation unit 112, and the other end of the operational amplification unit 113 is connected to the first input pin. The operational amplification unit 113 is used to amplify the signal of the low-voltage sampling analog signal. The isolation unit 112 can amplify the small signal by adjusting the feedback resistance. The operational amplification unit 113 comprises an operational amplifier U2A, an operational amplifier U4A, and an operational amplifier U6A, which can be used to improve the strength of the signal. In addition, the feedback resistance comprises a feedback resistance R19, a feedback resistance R29, and a feedback resistance R39. Therefore, the low-voltage sampling analog signal has sufficient strength, and the signal will not be distorted or weakened during transmission, processing, or further use.

[0039] Please refer to Figure 4The sampling metering circuit 10 further comprises a connection module 15, which comprises a first connection unit 151. The input end 1511 of the first connection unit is connected to the output end of the operational amplifier U2A, and the output end of the first connection unit 151 is connected to the first input pin V1N and the first input pin V1P. The first connection unit 151 comprises an inductor L108, which is used to suppress interference signals in the circuit, so that the interference signals are difficult to adversely affect the low-voltage sampling analog signal. The first connection unit 151 comprises resistors R143, R144, capacitors C141, and C142, which can perform filtering operations on the low-voltage sampling analog signal, and the resistors R143, R144, capacitors C141, and C142 can filter out noise interference in the circuit.

[0040] Please refer to Figure 4 The connection module 15 comprises a second connection unit 152. The input end 1521 of the second connection unit is connected to the output end of the operational amplifier U4A, and the output end of the second connection unit 152 is connected to the second input pin V2N and the second input pin V2P. The second connection unit 152 comprises an inductor L109, which is used to suppress interference signals in the circuit, so that the interference signals are difficult to adversely affect the low-voltage sampling analog signal. The second connection unit 152 comprises resistors R155, R156, capacitors C144, and C145, which can perform filtering operations on the low-voltage sampling analog signal, and the resistors R155, R156, capacitors C144, and C145 can filter out noise interference in the circuit.

[0041] Please refer to Figure 4 The connection module 15 comprises a third connection unit 153. The input end 1531 of the third connection unit is connected to the output end of the operational amplifier U6A, and the output end of the third connection unit 153 is connected to the third input pin V3N and the third input pin V3P. The third connection unit 153 comprises an inductor L110, which is used to suppress interference signals in the circuit, so that the interference signals are difficult to adversely affect the low-voltage sampling analog signal. The third connection unit 153 comprises resistors R165, R166, capacitors C148, and C149, which can perform filtering operations on the low-voltage sampling analog signal, and the resistors R165, R166, capacitors C148, and C149 can filter out noise interference in the circuit.

[0042] Please refer to Figure 3The current conversion module 12 includes a current transformer unit 121. One end of the current transformer unit 121 is connected to the sampling module 16, and the other end of the current transformer unit 121 is connected to the second input pin. The current transformer unit 121 is used for current conversion operation on the sampled analog signal of high current, and generates a sampled analog signal of low current. The current transformer unit 121 includes a current transformer CT_A, a current transformer CT_B, a current transformer CT_C, and a current transformer CT_N. The current transformer unit 121 also includes resistors R102, R106, R113, R114, R122, R124, R127, and R128. The resistors R102 and R106 are matching sampling resistors of the current transformer CT_A, and the resistors R113 and R114 are matching sampling resistors of the current transformer CT_B. The resistors R122 and R124 are matching sampling resistors of the current transformer CT_C, and the resistors R127 and R128 are matching sampling resistors of the current transformer CT_N. The current transformer has the function of current conversion, and can convert the high-current signal into a safe low-current signal for signal measurement and protection of subsequent circuit elements.

[0043] Please refer to Figure 3 The current conversion module 12 includes an anti-interference unit 122. One end of the anti-interference unit 122 is connected to the current transformer unit 121, and the other end of the anti-interference unit 122 is connected to the second input pin. The anti-interference unit 122 is used to suppress the interference of group pulses on the sampled analog signal of low current. The anti-interference unit 122 includes inductors L100, L101, L102, L103, L104, L105, L106, and L107. Inductive anti-interference can achieve suppression of interference signals through its electromagnetic induction characteristics. Specifically, inductors can hinder the change of current, which can help reduce interference signals in the circuit.

[0044] Please refer to Figure 3The current conversion module 12 comprises a filtering unit 123. One end of the filtering unit 123 is connected with the anti-interference unit 122, and the other end of the anti-interference unit 122 is connected with the second input pin. The filtering unit 123 is used for filtering operation on the low-current sampling analog signal. The filtering unit 123 comprises filtering resistors R101, R108, R111, R116, R119, R125, R126 and R129, and further comprises filtering capacitors C102, C103, C106, C107 and C108. The filtering unit 123 further comprises filtering capacitors C114, C115, C118, C119 and C120. The filtering unit 123 further comprises filtering capacitors C122, C123, C126, C130 and C131. The filtering unit 123 further comprises filtering capacitors C132, C133, C134, C137 and C138. The current conversion module 12 adopts a differential circuit design, and is provided with the filtering unit 123. Therefore, the current conversion module 12 can effectively remove the stray noise signal in the circuit.

[0045] Please refer to Figure 3 and Figure 5 The metering module 13 comprises a power supply unit 131, and the integrated metering chip U100 comprises an analog power supply pin and a digital power supply pin. The power supply unit 131 is connected with the analog power supply pin and the digital power supply pin, and is used for outputting a power supply voltage for power supply operation on the integrated metering chip U100. The input end of the power supply unit 131 is connected with a power supply VDD, the output end of the power supply unit 131 is respectively connected with the analog power supply pin VPP and the digital power supply pin DVDD, and the power supply unit 131 is provided with a voltage stabilizing chip U113 and a voltage stabilizing chip U400. The model of the voltage stabilizing chip U113 is HT7550-1, and the model of the voltage stabilizing chip U400 is SGM2034. Both the voltage stabilizing chip U113 and the voltage stabilizing chip U400 have the function of stabilizing voltage. The power supply VDD can output a power supply voltage, and the voltage stabilizing chip U113 and the voltage stabilizing chip U400 can stabilize the power supply voltage, so that the power supply unit 131 can output a 3.3V power supply voltage.

[0046] The working principle of the utility model is: when the sampling measurement circuit 10 works, the sampling analog signal output by the sampling module 16, voltage conversion module 11 receives the sampling analog signal. Voltage conversion module 11 can carry out voltage conversion operation to the high voltage sampling analog signal through the voltage dividing unit 111, so that voltage conversion module 11 can generate low voltage sampling analog signal. In order to isolate the interference of ground to low voltage sampling analog signal, voltage conversion module 11 is provided with isolation unit 112. And, because voltage conversion module 11 is provided with operational amplifier unit 113, so operational amplifier unit 113 can carry out signal amplification operation to low voltage sampling analog signal.

[0047] Meanwhile, current conversion module 12 receives the sampling analog signal. Current conversion module 12 can carry out current conversion operation to the high current sampling analog signal through the current transformer unit 121, so that current conversion module 12 can generate low current sampling analog signal. In order to suppress the interference of group pulse to low current sampling analog signal, the current conversion module 12 is provided with anti-interference unit 122. In order to carry out filtering operation to low current sampling analog signal, the current conversion module 12 is provided with filter unit 123.

[0048] Then, measurement module 13 receives low voltage sampling analog signal and low current sampling analog signal. Then, measurement module 13 can carry out analog-digital conversion operation to low voltage sampling analog signal and low current sampling analog signal, so that measurement module 13 can generate digital signal. Subsequently, microcontroller module 14 can receive the digital signal. Moreover, microcontroller module 14 can carry out data processing operation to digital signal, and microcontroller module 14 can save the result of data processing in its data memory.

[0049] The utility model provides a kind of sampling measurement circuit, the sampling measurement circuit includes voltage conversion module, current conversion module, measurement module and microcontroller module.Voltage conversion module can carry out voltage conversion to the sampling analog signal of high voltage, to generate the sampling analog signal of low voltage.Current conversion module can carry out current conversion to the sampling analog signal of high current, to generate the sampling analog signal of low current.Therefore, sampling analog signal passes through voltage conversion module and current conversion module, can be converted into low voltage, low current signal.Further, measurement module can safely carry out AD conversion to the sampling analog signal of low voltage and the sampling analog signal of low current, to generate digital signal.Microcontroller module can also safely digital signal carries out data processing, and the result of data processing is saved in its data memory.Voltage conversion module and current conversion module are effectively protected measurement module and microcontroller module, and can avoid high voltage, large current signal damage measurement module and microcontroller module.Effectively solve the technical problem that existing sampling circuit is easily damaged by large voltage or large current.The sampling measurement circuit is provided with voltage conversion module and current conversion module, also be conducive to avoiding measuring equipment and operator to be damaged by electrical breakdown, overcurrent damage etc.

[0050] In summary, although the utility model has disclosed as above with preferred embodiment, the above preferred embodiment is not used to limit the utility model, ordinary skilled in the art can make various changes and decorations without departing from the spirit and scope of the utility model, therefore the protection scope of the utility model is accurate with the range defined by claim.

Claims

1. A sampling metering circuit, characterized by, It includes, a voltage conversion module receiving the sampled analog signal output by the sampling module, for voltage conversion operation on the high-voltage sampled analog signal to generate the low-voltage sampled analog signal, the voltage conversion module comprising an isolation unit for isolating the ground from the interference generated by the low-voltage sampled analog signal; a current conversion module receiving the sampled analog signal output by the sampling module, for current conversion operation on the high-current sampled analog signal to generate the low-current sampled analog signal; a metering module connected to the voltage conversion module and the current conversion module, respectively, receiving the low-voltage sampled analog signal and the low-current sampled analog signal, for analog-to-digital conversion operation on the low-voltage sampled analog signal and the low-current sampled analog signal to generate a digital signal; a microcontroller module connected to the metering module, receiving the digital signal, for data processing operation on the digital signal, and saving the data processing result in its data storage.

2. The sampling metrology circuit of claim 1, wherein, The metering module includes an integrated metering chip, the integrated metering chip includes a first input pin, a second input pin and an output pin, the first input pin is connected to the voltage conversion module, and the first input pin is used to receive the low-voltage sampled analog signal; the second input pin is connected to the voltage conversion module, and the second input pin is used to receive the low-current sampled analog signal; The integrated metering chip is used for analog-to-digital conversion operation on the low-voltage sampled analog signal and the low-current sampled analog signal to generate a digital signal; the output pin is connected to the microcontroller module, and the output pin is used to output the digital signal.

3. The sampling metrology circuit of claim 2, wherein, The voltage conversion module includes a voltage dividing unit, one end of the voltage dividing unit is connected to the sampling module, and the other end of the voltage dividing unit is connected to the isolation unit, and the voltage dividing unit is used for voltage conversion operation on the high-voltage sampled analog signal to generate the low-voltage sampled analog signal.

4. The sampling metrology circuit of claim 3, wherein, The voltage conversion module includes an operational amplifier unit, one end of the operational amplifier unit is connected to the isolation unit, and the other end of the operational amplifier unit is connected to the first input pin, and the operational amplifier unit is used for signal amplification operation on the low-voltage sampled analog signal.

5. The sampling metrology circuit of claim 2, wherein, The current conversion module includes a current transformer unit, one end of the current transformer unit is connected to the sampling module, and the other end of the current transformer unit is connected to the second input pin, and the current transformer unit is used for current conversion operation on the high-current sampled analog signal to generate the low-current sampled analog signal.

6. The sampling metrology circuit of claim 5, wherein, The current conversion module includes an anti-interference unit, one end of the anti-interference unit is connected to the current transformer unit, and the other end of the anti-interference unit is connected to the second input pin, and the anti-interference unit is used to suppress the interference generated by the group pulse on the low-current sampled analog signal.

7. The sampling metrology circuit of claim 6, wherein, The current conversion module comprises a filtering unit, one end of the filtering unit is connected with the anti-interference unit, and the filtering unit is used for filtering operation on the sampling analog signal with low current.

8. The sampling metrology circuit of claim 2, wherein, The metering module comprises a power supply unit, the integrated metering chip comprises an analog power supply pin and a digital power supply pin, the power supply unit is connected with the analog power supply pin and the digital power supply pin, and the power supply unit is used for outputting a power supply voltage, which is used for power supply operation on the integrated metering chip.

9. A circuit board, characterized by It comprises the sampling metering circuit according to any one of claims 1-8.

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