CN103647557B - Adc circuit, ic for energy metering and electric energy metered system - Google Patents

Abstract

The invention relates to an ADC circuit, an electric energy metering circuit and an electric energy metering system. Wherein, the ADC circuit includes a switch resistor circuit; a first operational amplifier, whose input terminal is connected to the switch resistor circuit; a second operational amplifier, whose input terminal is connected to an output terminal of the first operational amplifier through a resistor; a quantizer, whose input terminal is connected to the output terminal of the first operational amplifier. The output terminal of the second operational amplifier is connected, and its output terminal is used to output the signal after comparing and quantizing the output signal of the second operational amplifier; the digital-to-analog converter module, its input terminal is connected with the output terminal of the quantizer, and its output terminal Feedback is connected to the input of the first operational amplifier and the input of the second operational amplifier. The first operational amplifier and the second operational amplifier of the ADC circuit of the embodiment of the present invention are connected through a resistor, and the signal between the two is continuously transmitted, which is a continuous-time sigma-delta ADC structure, which can improve the performance of the ADC circuit. accuracy.

Description

ADC circuit, electric energy metering circuit and electric energy metering system

technical field

The invention relates to the field of electric energy metering, in particular to an ADC circuit, an electric energy metering circuit and an electric energy metering system.

Background technique

In the field of electric energy measurement, an analog-to-digital converter (English: Analog to Digital Converter, abbreviation: ADC) is required to collect, amplify, and convert the input analog signal into a digital signal for the digital system to perform digital signal processing.

At present, there are three main implementation methods of ADC in the field of electric energy measurement. The first method is to integrate the gain amplifier (English: Programable Gain Amplifier, abbreviation: PGA) in the sampling capacitor of the sigma delta ADC, and realize it by adjusting the size of the sampling capacitor. Different gain magnifications. This structure needs to add a bootstrap circuit to boost the PMOS switch to transmit negative level signals; in addition, by adjusting the size of the capacitor to achieve different gain magnifications, it will cause loops in the first-stage integrator of the ADC. The bandwidth of the circuit is reduced. To meet the reasonable bandwidth requirements, the power consumption of the op amp must be increased.

The second way is to make the input signal pass through a continuous-time resistive PGA to control the input gain, and at the same time output the signal to the biased common-mode voltage, and directly send it to the sigma delta ADC for conversion. When an ADC circuit with this structure is input with a large negative signal such as -1V, the switch cannot be turned off, and leakage current will occur, thereby causing an error in the PGA output signal.

The third way is to realize the function of zero bias input by rationally configuring the gain of PGA and sigma delta ADC, and then reduce the bandwidth and power consumption design requirements of the first-stage integrator of sigma delta ADC. However, the ADC circuit with this structure requires an additional wave spreader op amp, and the additional PGA increases the noise source, and the filter circuit needs to be added, thereby increasing the complexity of the circuit.

The ADC circuit structures of the above three implementations all adopt the discrete-time sigma delta ADC structure, which has higher requirements on the bandwidth of the operational amplifier in the converter (generally greater than 10 times), and consumes a lot of power. In addition, the input end of each channel needs an anti-aliasing circuit for a large RC circuit, which increases the cost of the chip and the production cost of the PCB. In addition, the ADC with a discrete-time structure has high requirements for the establishment of the operational amplifier. When implementing a high-precision ADC, it is necessary to select a high-performance operational amplifier.

Contents of the invention

technical problem

In view of this, the technical problem to be solved by the present invention is how to improve the precision of the ADC circuit.

solution

In order to solve the above technical problems, according to an embodiment of the present invention, an analog-to-digital converter ADC circuit is provided, including: a switch resistance circuit; a first operational amplifier, whose input terminal is connected to the switch resistance circuit; a second operation Amplifier, its input end is connected with the output end of described first operational amplifier through resistance; Quantizer, its input end is connected with the output end of described second operational amplifier, and its output end is used for outputting to described second operational amplifier The output signal is compared with the quantized signal; the digital-to-analog converter module, its input terminal is connected to the output terminal of the quantizer, and its output terminal is feedback-connected to the input terminal of the first operational amplifier and the second operational amplifier amplifier input.

For the above ADC circuit, in a possible implementation, the switched resistor circuit is composed of two switched resistor arrays, and the switched resistor array includes: a first resistor, one end of which is connected to the output end of the signal to be processed, and the other end of which is connected to the output end of the signal to be processed. One end is connected to the input end of the first operational amplifier; at least one switch circuit includes a second resistor, a first switch and a second switch; one end of the second resistor is connected to one end of the first resistor, and the The other end of the second resistor is connected to the first end of the first switch; the second end of the first switch is grounded, and the third end of the first switch is connected to the first control pin of the configuration module; the second end of the first switch is connected to the first control pin of the configuration module; The second end of the second switch is connected to the other end of the second resistor, the first end of the second switch is connected to the other end of the first resistor, and the third end of the second switch is connected to the configuration module. Second control pin.

For the above ADC circuit, in a possible implementation manner, the first operational amplifier includes a first positive input terminal, a first negative input terminal, a first positive output terminal, and a first negative output terminal, so The first positive input terminal is connected to one of the switch resistor arrays, the first reverse input terminal is connected to another switch resistor array, and the first positive input terminal is connected to the first reverse output A capacitor is connected between the terminals, and a capacitor is connected between the first inverting input terminal and the first positive output terminal of the first operational amplifier.

For the above ADC circuit, in a possible implementation manner, the second operational amplifier includes a second positive input terminal, a second negative input terminal, a second positive output terminal, and a second negative output terminal, so A resistor is connected between the second reverse input terminal and the first reverse output terminal, a resistor is connected between the second positive input terminal and the first positive output terminal, and the second positive A capacitor is connected between the forward input terminal and the second reverse output terminal, and a capacitor is connected between the second reverse input terminal and the second positive output terminal.

For the above ADC circuit, in a possible implementation manner, the first input terminal of the quantizer is connected to the second positive output terminal, and the second input terminal of the quantizer is connected to the second inverting output terminal. output connection.

For the above ADC circuit, in a possible implementation manner, the digital-to-analog converter module includes two digital-to-analog conversion circuits, and the output terminal of one of the digital-to-analog converter modules is connected to the first positive input terminal respectively. and the first inverting input terminal is connected, and the output terminal of the other digital-to-analog converter module is respectively connected to the second positive input terminal and the second inverting input terminal.

For the above ADC circuit, in a possible implementation manner, the first switch and/or the second switch is a field effect transistor; the first end of the first switch and/or the second switch, The second terminal and the third terminal are respectively the source, the drain and the gate of the field effect transistor.

In order to solve the above technical problems, according to another embodiment of the present invention, an electric energy metering circuit is provided, including: a power supply, a load to be measured, a first sampling resistor, and an ADC circuit; wherein, the power supply, the load to be measured It is connected in series with the first sampling resistor to form a loop; the ADC circuit is connected in parallel with the first sampling resistor; the ADC circuit adopts an ADC circuit with any structure in the embodiment of the present invention; the first sampling resistor’s The two ends are respectively connected to the two ends of the switch resistance circuit of the ADC circuit.

In order to solve the above technical problems, according to another embodiment of the present invention, an electric energy metering circuit is provided, including: a power supply, a load to be measured, a second sampling resistor, a third sampling resistor, a fourth sampling resistor and an ADC circuit; wherein , the ADC circuit adopts an ADC circuit with any structure in the embodiment of the present invention; one end of the second sampling resistor is connected to the connection end between the power supply and the load to be measured, and the other end of the second sampling resistor One end of the third sampling resistor and one end of the switch resistor circuit of the ADC circuit are connected; the other end of the third sampling resistor is grounded; one end of the fourth sampling resistor is connected to the switch resistor circuit of the ADC circuit The other end of the fourth sampling resistor is connected to the ground.

In order to solve the above technical problems, according to another embodiment of the present invention, an electric energy metering system is provided, including: a current metering circuit and a voltage metering circuit; wherein, the current metering circuit adopts any structure in the embodiments of the present invention The electric energy metering circuit; the voltage metering circuit adopts the electric energy metering circuit of any structure in the embodiment of the present invention.

Beneficial effect

The first operational amplifier and the second operational amplifier of the ADC circuit in the embodiment of the present invention are connected through a resistor, and the signal between the two is continuously transmitted, which is a continuous time sigma-delta ADC structure, which can improve the ADC circuit accuracy. In addition, the first operational amplifier and the switch resistor circuit in the ADC circuit of the embodiment of the present invention can realize the function of a gain amplification operational amplifier (PGA), without using an independent PGA, avoiding the noise introduced by the PGA, and reducing the number of operational amplifiers used. The number of amplifiers, resistors and capacitors can save chip cost.

Other features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 shows the structural block diagram of the analog-to-digital converter ADC circuit according to an embodiment of the present invention;

2 shows a specific circuit diagram of an analog-to-digital converter ADC circuit according to another embodiment of the present invention;

3a shows a schematic circuit diagram of the connection relationship between the switch resistor array and the configuration module of the analog-to-digital converter ADC circuit according to another embodiment of the present invention;

Figure 3b shows a specific circuit diagram of a digital-to-analog conversion circuit according to an embodiment of the present invention;

Fig. 4 shows a schematic diagram of an electric energy metering circuit according to an embodiment of the present invention;

Fig. 5 shows a schematic diagram of an electric energy metering circuit according to another embodiment of the present invention;

Fig. 6 shows a schematic diagram of an electric energy metering system according to an embodiment of the present invention.

detailed description

Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the accompanying drawings. The same reference numbers in the figures indicate functionally identical or similar elements. While various aspects of the embodiments are shown in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior or better than other embodiments.

In addition, in order to better illustrate the present invention, numerous specific details are given in the specific embodiments below. It will be understood by those skilled in the art that the present invention may be practiced without certain of the specific details. In some instances, methods, means, components and circuits well known to those skilled in the art have not been described in detail in order to highlight the gist of the present invention.

Example 1

FIG. 1 shows a structural block diagram of an analog-to-digital converter ADC circuit according to an embodiment of the present invention. As shown in FIG. 1 , the ADC circuit mainly includes: a switch resistor circuit 110 , a first operational amplifier 120 , a second operational amplifier 130 , a quantizer 140 , and a digital-to-analog converter module 150 . Wherein, the input terminal of the first operational amplifier 120 is connected with the switch resistance circuit 110, the input terminal of the second operational amplifier 130 is connected with the output terminal of the first operational amplifier 120 through the resistor 160, the input terminal of the quantizer 140 is connected with the second operational amplifier The output terminal of 130 is connected, and the output terminal of quantizer 140 is used for outputting the signal after comparing and quantizing the output signal of the second operational amplifier, and the input terminal of digital-to-analog converter module 150 is connected with the output terminal of quantizer 140, The output terminal of the digital-to-analog converter module 150 is feedback-connected to the input terminal of the first operational amplifier 120 and the input terminal of the second operational amplifier 130 .

In a possible implementation manner, the switched resistor circuit 110 may be composed of two switched resistor arrays, and by controlling switches of the switched resistor arrays to be turned on or off, gains of different multiples can be realized.

The first operational amplifier and the second operational amplifier of the ADC circuit of this embodiment are connected through a resistor, and the signal between the two is continuously transmitted, which is a continuous-time sigma-delta ADC structure, which can improve the performance of the ADC circuit. precision. In addition, the first operational amplifier and the switch resistor circuit in the ADC circuit of this embodiment can realize the function of a gain amplification operational amplifier (PGA), without using an independent PGA, avoiding the noise introduced by the PGA, and reducing the number of operational amplifiers used. , the number of resistors and capacitors can save chip cost.

Example 2

FIG. 2 shows a specific circuit diagram of an analog-to-digital converter ADC circuit according to another embodiment of the present invention. Components with the same numbers in FIG. 2 as those in FIG. 1 have the same functions, and for the sake of brevity, detailed descriptions of these components are omitted.

In a possible implementation, the switched resistor circuit 110 of the ADC circuit shown in FIG. 2 is composed of two switched resistor arrays 111 and 112, wherein the switched resistor array 111 and the switched resistor array 112 may be modules with the same structure.

As shown in FIG. 3 a , the switch resistor arrays 111 and 112 may include: a first resistor 310 and four switch circuits. Wherein, one end A of the first resistor 310 is connected to the output end of the signal to be processed, and the other end B is connected to the input end of the first operational amplifier 120 . The four switch circuits may be modules with the same structure, and each switch circuit may include a resistor and two switches. Specifically, taking a switch circuit as an example, the switch circuit includes a second resistor 320 and two switches 321, 322, wherein, one end A of the second resistor 320 is connected to one end A of the first resistor 310, and the second resistor 320 The other end B of the first switch 321 is connected to the first end S of the first switch 321; the second end D of the first switch 321 is grounded, and the third end G of the first switch 321 is connected to the first control pin of the configuration module; The second terminal D is connected to the other terminal B of the second resistor 320, the first terminal S of the second switch 322 is connected to the other terminal B of the first resistor 310, and the third terminal G of the second switch 322 is connected to the second terminal of the configuration module. control pin.

The schematic diagram of the connection relationship between the configuration module and the switch resistance circuit 110 is shown in FIG. 3a. In order to describe the connection relationship between the configuration module and the switch resistance circuit 110 more clearly and concisely, FIG. The connection relationship of the configuration modules is consistent with the connection relationship described in Fig. 3a. The first control pin of the configuration module can be the SELB pin, and the second control pin can be the SEL pin. The configuration module controls the signals of the EN pin and the S<1-0> pin to the SELB pin and the S<1-0> pin. The SEL pin is configured with a corresponding value, so as to control whether each group of switches in the four-way switch circuit is gated, thereby achieving different multiples of gain. The relationship between the value of the EN pin and the S<1-0> pin and the gain can be shown in Table 1.

Table 1 Relationship between EN pin and S<1-0> pin value and gain

EN S<1-0> gain 0 ×× 16 1 00 8 1 01 4 1 10 2 1 11 1

In a possible implementation manner, the structure of the switch resistor array 111 and the switch resistor array 112 can be shown in FIG. 3a, if the resistance value of the first resistor 310 is R, then the resistance value of the second resistor 320 can be R, The resistance value of the resistor 330 may be R/2, the resistance value of the resistor 340 may be R/4, and the resistance value of the resistor 350 may be R/8. If a 4-fold gain is to be realized, the first switch 321 and the switch 331 can be turned off, and the second switch 322 and the switch 332 are turned on, so that the second resistor 320 and the resistor 330 are connected; and the switch 341 and the switch 351 are turned on, The switch 342 and the switch 352 are turned on, so that the resistor 340 and the resistor 350 are not connected. That is to say, if the equivalent resistance values of the switch resistor array 111 and the switch resistor array 112 are doubled, the gain of the ADC circuit in this embodiment is doubled.

In a possible implementation, the switches in the switch resistor array shown in FIG. 3a may all be field effect transistors, and the first terminal S, the second terminal D and the third terminal G are respectively The source S, drain D and gate G of the field effect transistor.

It should be noted that although a four-way switch circuit is used as an example to describe the switch resistance circuit structure of the ADC circuit as above, those skilled in the art can understand that the present invention should not be limited thereto. In fact, users can flexibly set the number of switching circuits according to personal preferences and/or actual application scenarios to achieve desired gain multiples.

The switch resistor circuit structure of the ADC circuit of the present embodiment, one end B of each resistor in the four-way switch circuit is grounded through the field effect tube switch on the one hand, and is connected to the input terminal of the operational amplifier through another field effect tube switch on the other hand , so that the influence of unused resistors on the performance of the ADC circuit can be completely disconnected. In the actual test and measurement process, two switches are used in one switch circuit, and when one switch cannot be turned off, the other switch can be used to turn off, which can avoid the leakage problem caused by the switch cannot be turned off, thus ensuring accurate selection the amplification gain.

In a possible implementation manner, as shown in FIG. 2, the first operational amplifier 120 includes a first positive input terminal, a first negative input terminal, a first positive output terminal and a first negative output terminal, so The first positive input terminal is connected to the switch resistor array 111, the first reverse input terminal is connected to the switch resistor array 112, and the first positive input terminal is connected to the first reverse output terminal. A capacitor 211, a capacitor 212 is connected between the first inverting input terminal and the first positive output terminal.

In a possible implementation, as shown in FIG. 2, the second operational amplifier 130 includes a second positive input terminal, a second negative input terminal, a second positive output terminal and a second negative output terminal, so A resistor 162 is connected between the second reverse input terminal and the first reverse output terminal, a resistor 161 is connected between the second positive input terminal and the first positive output terminal, and the first A capacitor 221 is connected between the two forward input terminals and the second reverse output terminal, and a capacitor 222 is connected between the second reverse input terminal and the second forward output terminal. The resistance values of the resistor 161 and the resistor 162 can be the same.

It should be noted that the first operational amplifier 120 may be an operational amplifier with a chopper circuit, and the chopper circuit can reduce the noise of the operational amplifier, thereby improving the measurement accuracy of the ADC circuit to a certain extent. In addition, the capacitor 211, the capacitor 212, the capacitor 221, and the capacitor 222 can improve the stability of the operational amplifier, and can also ensure the accuracy of the output signal of the operational amplifier.

In a possible implementation, as shown in FIG. 2, the first input terminal C1 of the quantizer 140 is connected to the second positive output terminal of the second operational amplifier 130, and the second input terminal C2 is connected to the second positive output terminal of the second operational amplifier 130. The second inverting output terminal connection. According to specific application scenarios and actual needs, the quantizer 140 may be a one-bit comparator, or may be a 4-bit or 8-bit comparator.

In a possible implementation manner, as shown in FIG. 2 , the digital-to-analog converter module 150 may include two digital-to-analog conversion circuits 151 and 152, wherein the output terminals of the digital-to-analog conversion circuit 151 are respectively connected to the first operational amplifier 120 The first non-inverting input end and the first inverting input end of the digital-to-analog conversion circuit 152 are respectively connected with the second non-inverting input end and the second inverting input end of the second operational amplifier 130, for The digital signal output by the quantizer 140 is converted into an analog signal and fed back to the first operational amplifier 120 and the second operational amplifier 130 .

In a possible implementation manner, the structure of the digital-to-analog conversion circuit 151 and the digital-to-analog conversion circuit 152 can be the same, and both can adopt the structure shown in FIG. Register 370, resistance 381, resistance 382, switch 391, switch 392, wherein, Mj[K] end is the input end of digital-to-analog conversion circuit, is connected with the output end of quantizer 140, and Pj[K] is Mj[K] Through the signal output by the encoder 360, the Vo1 end and the Vo2 end are the output ends of the digital-to-analog conversion circuit, which are respectively connected with the first forward input end and the first reverse input end of the first operational amplifier 120, or respectively connected with the second The second non-inverting input terminal of the operational amplifier 130 is connected to the second inverting input terminal.

The first operational amplifier and the second operational amplifier of the ADC circuit of this embodiment are connected through a resistor, and the signal between the two is continuously transmitted, which is a continuous-time sigma-delta ADC structure, which can improve the performance of the ADC circuit. precision. In addition, the first operational amplifier and the switch resistor circuit in the ADC circuit of this embodiment can realize the function of a gain amplification operational amplifier (PGA), without using an independent PGA, avoiding the noise introduced by the PGA, and reducing the number of operational amplifiers used. , the number of resistors and capacitors can save chip cost.

Example 3

Fig. 4 shows a schematic diagram of an electric energy metering circuit according to an embodiment of the present invention, and the electric energy metering circuit can be used to measure the magnitude of current in a household circuit. As shown in FIG. 4 , the electric energy metering circuit may include: a power supply 510 , a load to be measured 520 , a first sampling resistor 530 and an ADC circuit 540 .

Specifically, the power supply 510, the load to be tested 520, and the first sampling resistor 530 are connected in series to form a loop, the load to be tested 520 can be a household appliance, etc., and the loop can be a circuit loop including a household appliance in a household circuit, an ADC circuit 540 is connected in parallel with the first sampling resistor 530; the ADC circuit 540 can be an ADC circuit adopting the structure described in embodiment 1 or embodiment 2; the two ends of the first sampling resistor 530 are respectively connected to the two ends of the switch resistance circuit of the ADC circuit 540 . The current flowing through the first sampling resistor 530 is amplified by the ADC circuit 540 and converted into a digital signal, and the magnitude of the current in the loop can be accurately obtained through the peripheral processing circuit.

It should be noted that a current source can be externally connected to the switch resistance circuit of the ADC circuit 540 to provide a small current for the input terminal of the first operational amplifier, thereby providing a common mode point for the operational amplifier of this stage. Therefore, the The electric energy metering circuit can ensure that the ADC circuit 540 can still work normally when the external large signal is negatively input, thereby realizing external zero bias input and saving costs. Moreover, the ADC circuit 540 used in the electric energy metering circuit of this embodiment has high precision, so that the accuracy of the output result of the electric energy metering circuit can be guaranteed.

Example 4

Fig. 5 shows a schematic diagram of an electric energy metering circuit according to another embodiment of the present invention, and the electric energy metering circuit can be used to measure the voltage in a household circuit. As shown in FIG. 5 , the electric energy metering circuit may include: a power supply 610 , a load to be measured 620 , a second sampling resistor 630 , a third sampling resistor 640 , a fourth sampling resistor 650 and an ADC circuit 660 .

Specifically, the power supply 610 and the load to be tested 620 can form a circuit loop in a home circuit, the load to be tested 620 can be a household appliance, etc., and the ADC circuit 660 can be an ADC circuit using any structure in the above-mentioned embodiments. One end A of the sampling resistor 630 is connected to the connection end C of the power supply 610 and the load to be measured 620, and the other end B of the second sampling resistor 630 is connected to one end of the switch resistor circuit of the ADC circuit 660; one end A of the third sampling resistor 640 is connected to the ADC One end of the switch resistor circuit of the circuit 660 is connected, and the other end B of the third sampling resistor 640 is grounded; one end A of the fourth sampling resistor 650 is connected to the other end of the switch resistor circuit of the ADC circuit 660, and the fourth sampling resistor 650 The other end B is grounded.

In a possible implementation manner, the resistance value of the third sampling resistor 640 may be the same as that of the fourth sampling resistor 650, and the voltage across the third sampling resistor 640 is amplified by the ADC circuit 660 and converted into a digital signal, Through the peripheral processing circuit, information such as the magnitude and stability of the voltage at both ends of the load 620 to be tested in the loop can be accurately obtained.

In addition, a current source can be externally connected to the switched resistance circuit of the ADC circuit 660 to provide a small current for the input terminal of the first operational amplifier, thereby providing a common mode point for the operational amplifier of this stage. Therefore, the electric energy measurement circuit of this embodiment It can be guaranteed that the ADC circuit 660 can still work normally when the external large signal is negatively input, thereby realizing external zero bias input and saving costs. Moreover, the ADC circuit 660 used in the electric energy metering circuit of this embodiment has high precision, so that the accuracy of the output result of the electric energy metering circuit can be guaranteed.

Example 5

Fig. 6 shows a schematic diagram of an electric energy metering system according to an embodiment of the present invention, which can be used to measure the current and/or voltage in a household circuit. As shown in FIG. 6 , the electric energy metering system may include: a current metering circuit and a voltage metering circuit. Wherein, the current metering circuit may be the electric energy metering circuit of Embodiment 3, for details, please refer to FIG. 4 and its related descriptions. The voltage metering circuit may be the electric energy metering circuit of Embodiment 4, for details, refer to FIG. 5 and its related descriptions. Wherein, it is also possible to combine the electric energy metering circuits in Fig. 4 and Fig. 5 into one circuit. As shown in Figure 6, the electric energy metering system may include a power supply 710, a load to be measured 720, a first sampling resistor 530, a second sampling resistor 630, a third sampling resistor 640, a fourth sampling resistor 650, an ADC circuit 540 and an ADC circuit 660 . The power supply and the load to be measured of the current metering circuit and the voltage metering circuit can be shared, and the first sampling resistor 530 can also be included when measuring the voltage. Since the resistance of the first sampling resistor is small, the effect of voltage division can be ignored.

It should be noted that the current metering circuit and the voltage metering circuit of the electric energy metering system in the embodiment of the present invention can perform the test and measurement of the circuit at the same time, or separately, and those skilled in the art should understand that, as described in Embodiment 3 and Embodiment 4 All possible implementation manners can be applied to this embodiment and can obtain the same beneficial effect, and will not be repeated here.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. Should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (9)

1. An analog-to-digital converter ADC circuit is characterized in that, comprising: switch resistor circuit; a first operational amplifier, the input terminal of which is connected to the switched resistor circuit; a second operational amplifier, the input of which is connected to the output of the first operational amplifier through a resistor; A quantizer, whose input terminal is connected to the output terminal of the second operational amplifier, and whose output terminal is used to output a signal after comparing and quantizing the output signal of the second operational amplifier; A digital-to-analog converter module, the input of which is connected to the output of the quantizer, and the output of which is feedback-connected to the input of the first operational amplifier and the input of the second operational amplifier; Wherein, the switch resistor circuit is composed of two switch resistor arrays, one switch resistor array is connected to the non-inverting input terminal of the first operational amplifier, and the other switch resistor array is connected to the inverting input terminal of the first operational amplifier. connect; The switch resistor array includes: A first resistor, one end of which is connected to the output end of the signal to be processed, and the other end of which is connected to the input end of the first operational amplifier; At least one switch circuit, which includes a second resistor, a first switch, and a second switch; one end of the second resistor is connected to one end of the first resistor, and the other end of the second resistor is connected to the first switch the first end of the first switch; the second end of the first switch is grounded, the third end of the first switch is connected to the first control pin of the configuration module; the second end of the second switch is connected to the second resistor the other end of the second switch, the first end of the second switch is connected to the other end of the first resistor, and the third end of the second switch is connected to the second control pin of the configuration module. 2. ADC circuit according to claim 1, is characterized in that, The first operational amplifier includes a first positive input terminal, a first negative input terminal, a first positive output terminal and a first negative output terminal, and the first positive input terminal is connected to one of the switch resistor arrays connected, the first reverse input terminal is connected to another switch resistor array, a capacitor is connected between the first positive input terminal and the first reverse output terminal, and the first reverse input terminal A capacitor is connected between the terminal and the first positive output terminal of the first operational amplifier. 3. ADC circuit according to claim 2, is characterized in that, The second operational amplifier includes a second non-inverting input terminal, a second inverting input terminal, a second non-inverting output terminal and a second inverting output terminal, and the second inverting input terminal is connected to the first inverting input terminal. A resistor is connected between the output terminals, a resistor is connected between the second positive input terminal and the first positive output terminal, and a resistor is connected between the second positive input terminal and the second reverse output terminal. A capacitor is connected, and a capacitor is connected between the second inverting input terminal and the second positive output terminal. 4. The ADC circuit according to claim 3, wherein the first input terminal of the quantizer is connected to the second positive output terminal, and the second input terminal of the quantizer is connected to the second positive output terminal. Inverted output connection. 5. according to the described ADC circuit of claim 3 or 4, it is characterized in that, described digital-to-analog converter module comprises two digital-to-analog conversion circuits, and the output terminal of one described digital-to-analog conversion circuit is respectively connected with the first positive connected to the input terminal and the first inverting input terminal, and the output terminal of the other digital-to-analog conversion circuit is respectively connected to the second positive input terminal and the second inverting input terminal. 6. The ADC circuit according to any one of claims 1 to 4, wherein the first switch and/or the second switch is a field effect transistor; The first terminal, the second terminal and the third terminal of the first switch and/or the second switch are respectively the source, the drain and the gate of the field effect transistor. 7. An electric energy metering circuit, characterized in that, comprising: Power supply, load to be tested, first sampling resistor and ADC circuit; Wherein, the power supply, the load to be tested and the first sampling resistor are connected in series to form a loop; The ADC circuit is connected in parallel with the first sampling resistor; The ADC circuit adopts the ADC circuit according to any one of claims 1 to 6; The two ends of the first sampling resistor are respectively connected to the two ends of the switch resistance circuit of the ADC circuit. 8. An electric energy metering circuit, characterized in that, comprising: A power supply, a load to be measured, a second sampling resistor, a third sampling resistor, a fourth sampling resistor and an ADC circuit; Wherein, the ADC circuit adopts the ADC circuit according to any one of claims 1 to 6; One end of the second sampling resistor is connected to the connection end of the power supply and the load to be measured, and the other end of the second sampling resistor is connected to one end of the third sampling resistor and the switch resistor circuit of the ADC circuit. One end is connected; the other end of the third sampling resistor is grounded; one end of the fourth sampling resistor is connected to the other end of the switch resistor circuit of the ADC circuit, and the other end of the fourth sampling resistor is grounded. 9. An electric energy metering system, characterized in that it comprises: Current metering circuit and voltage metering circuit; Wherein, the current metering circuit adopts the electric energy metering circuit described in claim 7; The voltage metering circuit adopts the electric energy metering circuit described in claim 8 .