CN219871530U - Voltage measuring device - Google Patents

Abstract

A voltage measuring device comprises a signal processing circuit, an adjustable voltage dividing circuit, an adjustable gain circuit, an analog-to-digital conversion circuit and a main control circuit. The signal processing circuit processes the signal to be tested output by the circuit to be tested to obtain a positive voltage signal to be tested, the adjustable voltage dividing circuit can divide the signal to be tested output by the signal processing circuit according to a first control signal output by the main control circuit in different proportions, the adjustable gain circuit can amplify the signal to be tested output by the adjustable voltage dividing circuit according to a second control signal output by the main control circuit in different gains, the analog-to-digital conversion circuit carries out analog-to-digital conversion on the signal to be tested output by the adjustable gain circuit to obtain a digital signal, and the main control circuit can determine the voltage value of the signal to be tested according to the digital signal. The utility model can carry out different voltage division and gain configuration according to the voltage value of the signal to be measured, and can realize accurate measurement of the voltage of the signal to be measured.

Description

Voltage measuring device

Technical Field

The present utility model relates to the field of circuit board assembly detection technology, and in particular, to a voltage measurement device.

Background

At present, the functions of electronic products tend to be diversified, the circuit system of the electronic products is increasingly complex, and the number of the included electronic components is increasingly large. In order to ensure that the electrical performance of the circuit board assembly meets the design requirement after the surface mount technology (surface mount technology, SMT) is finished, bad products are screened out, and a large amount of manpower and material resources are required to be input by a production enterprise to test the electrical performance of the products.

In the conventional signal measurement scheme, signals read from the circuit board assembly are generally sent to a micro control unit (microcontroller unit, MCU) for analysis, and whether signal transmission is wrong or not is determined. Sometimes, the circuit on the circuit board assembly breaks down, so that the signal voltage is abnormal, but as long as the signal level of the broken circuit is still within an acceptable range, the MCU can still analyze the signal, namely, the abnormality is not considered to occur, the level fault on the circuit cannot be detected, the defective products of the type flow into the market, and if superimposed noise occurs on the circuit, the situation that the signal cannot work normally is most likely to occur.

Disclosure of Invention

In view of the foregoing, it is necessary to provide a voltage measuring device capable of accurately measuring the voltage of a signal to be measured, so as to realize accurate screening of bad products.

The embodiment of the utility model discloses a voltage measuring device which comprises a signal processing circuit, an adjustable voltage dividing circuit, an adjustable gain circuit, an analog-to-digital conversion circuit and a main control circuit. The signal processing circuit is used for receiving a signal to be detected output by the circuit to be detected and processing the signal to be detected to obtain a signal to be detected of positive voltage; the adjustable voltage dividing circuit is respectively and electrically connected with the signal processing circuit, the adjustable gain circuit and the main control circuit, and is used for setting a voltage dividing ratio according to a first control signal output by the main control circuit and dividing a signal to be detected output by the signal processing circuit based on the set voltage dividing ratio; the adjustable gain circuit is electrically connected to the main control circuit and is used for setting the gain according to a second control signal output by the main control circuit and amplifying a signal to be detected output by the adjustable voltage dividing circuit according to the set gain; the analog-to-digital conversion circuit is electrically connected between the adjustable gain circuit and the main control circuit, and is used for performing analog-to-digital conversion on a signal to be detected output by the adjustable gain circuit to obtain a digital signal, and inputting the digital signal to the main control circuit; the main control circuit is used for determining the voltage value of the signal to be detected according to the digital signal converted by the analog-to-digital conversion circuit.

By adopting the technical scheme, different voltage division and gain configuration can be carried out according to the voltage value of the signal to be measured, so that the voltage of the signal to be measured can be accurately measured, for example, the corresponding voltage division ratio and gain are set based on the estimated voltage value of the signal to be measured, and then the voltage value of the signal to be measured is measured.

In some embodiments, the voltage measurement device further includes an electronic switch gating circuit, the electronic switch gating circuit is electrically connected between the circuit to be measured and the signal processing circuit, and is further electrically connected to the main control circuit, and the electronic switch gating circuit is configured to set a single channel input or a dual channel input according to a third control signal output by the main control circuit.

By adopting the technical scheme, the voltage measurement of the single-ended line and the differential line can be supported.

In some embodiments, the signal processing circuit is further configured to set a single-ended input process or a double-ended input process according to a fourth control signal output by the master circuit.

By adopting the technical scheme, the single-ended input processing or the double-ended input processing can be selected based on whether the line to be measured is a single-ended line or a differential line.

In some embodiments, if the signal to be detected is a differential signal, the electronic switch gating circuit is configured to set the third control signal output by the main control circuit to be the dual-channel input, and the main control circuit is configured to determine a voltage difference between the differential signals according to the digital signal converted by the analog-to-digital conversion circuit.

By adopting the technical scheme, the voltage difference value of the differential signal can be accurately measured.

In some embodiments, the signal processing circuit comprises: the first electronic switch comprises a first input end, a second input end, an output end and a control end, wherein the first input end of the first electronic switch is grounded, the second input end of the first electronic switch is electrically connected with the first output end of the electronic switch gating circuit, and the control end of the first electronic switch is electrically connected with the main control circuit; the second electronic switch comprises a first input end, a second input end, an output end and a control end, wherein the first input end of the second electronic switch is grounded, the second input end of the second electronic switch is electrically connected with the second output end of the electronic switch gating circuit, and the control end of the second electronic switch is electrically connected with the main control circuit; the first operational amplifier comprises a positive input end, a negative input end and an output end, wherein the positive input end of the first operational amplifier is electrically connected with the output end of the first electronic switch, the negative input end of the first operational amplifier is electrically connected with the output end of the second electronic switch, and the output end of the first operational amplifier is electrically connected with the adjustable voltage dividing circuit.

By adopting the technical scheme, single-ended input processing or double-ended input processing can be realized by gating the first electronic switch, the second electronic switch and the first operational amplifier.

In some embodiments, the adjustable voltage dividing circuit includes a plurality of voltage dividing branches with different voltage dividing ratios, and the adjustable voltage dividing circuit is configured to select a voltage dividing branch to be connected between the signal processing circuit and the adjustable gain circuit according to a first control signal output by the main control circuit.

By adopting the technical scheme, different partial pressure treatments are carried out on the signal to be detected output by the signal processing circuit by selecting the partial pressure branches with different partial pressure ratios.

In some embodiments, the adjustable voltage divider circuit comprises: one end of the first resistor is electrically connected with the signal processing circuit, and the other end of the first resistor is electrically connected with the adjustable gain circuit; one end of each of the plurality of voltage dividing resistors is electrically connected to the other end of the first resistor; the third electronic switch comprises a plurality of input ends, output ends and a plurality of control ends, each input end of the plurality of input ends of the third electronic switch is electrically connected to the other end of each voltage dividing resistor in a one-to-one correspondence mode, the output end of the third electronic switch is grounded, and the plurality of control ends of the third electronic switch are electrically connected to the main control circuit.

By adopting the technical scheme, the voltage dividing branches with different voltage dividing ratios are selected by gating different voltage dividing resistors.

In some embodiments, the adjustable gain circuit comprises: the gain amplifier comprises a positive input end, a negative input end, a first gain adjusting end, a second gain adjusting end and an output end, wherein the positive input end of the gain amplifier is electrically connected with the adjustable voltage dividing circuit, the negative input end of the gain amplifier is grounded, and the output end of the gain amplifier is electrically connected with the analog-to-digital conversion circuit; the adjustable resistor unit comprises a first end, a second end and a control end, wherein the first end of the adjustable resistor unit is electrically connected with the first gain adjusting end of the gain amplifier, the second end of the adjustable resistor unit is electrically connected with the second gain adjusting end of the gain amplifier, the control end of the adjustable resistor unit is electrically connected with the main control circuit, and the adjustable resistor unit is used for setting impedance connected between the first gain adjusting end and the second gain adjusting end according to a second control signal output by the main control circuit.

By adopting the technical scheme, the gain of the gain amplifier is adjusted by adjusting the impedance between the first gain adjusting end and the second gain adjusting end of the gain amplifier.

In some embodiments, the adjustable resistance unit includes: a plurality of second resistors, wherein one end of each second resistor in the plurality of second resistors is electrically connected to a first gain adjustment end of the gain amplifier; the fourth electronic switch comprises a plurality of input ends, output ends and a plurality of control ends, each input end in the plurality of input ends of the fourth electronic switch is electrically connected to the other end of each second resistor in a one-to-one correspondence mode, the output end of the fourth electronic switch is electrically connected to the second gain adjusting end of the gain amplifier, and the plurality of control ends of the fourth electronic switch are electrically connected to the main control circuit.

By adopting the technical scheme, the impedance between the first gain adjusting end and the second gain adjusting end of the gain amplifier is adjusted by gating the second resistors with different resistance values, so that the gain of the gain amplifier is adjusted.

In some embodiments, the analog-to-digital conversion circuit comprises an analog-to-digital converter, and the master control circuit comprises a micro control unit that receives the digital signal input by the analog-to-digital converter through an SPI bus or an I2C bus.

By adopting the technical scheme, the micro control unit can receive the digital signals input by the analog-to-digital converter through buses such as SPI, I2C and the like.

Drawings

FIG. 1 is a functional block diagram of a voltage measuring device according to an embodiment of the present utility model.

FIG. 2 is a functional block diagram of another embodiment of the voltage measuring device of the present utility model.

FIG. 3 is a circuit diagram of a voltage measuring device according to an embodiment of the utility model.

Detailed Description

The technical solutions in the embodiments of the present utility model will be clearly described below with reference to the drawings in the embodiments of the present utility model.

It is understood that the connection relationship described in the present utility model refers to direct or indirect connection. For example, the connection between a and B may be a direct connection between a and B or an indirect connection between a and B via one or more other electrical components. For example, a may be directly connected to C, and C may be directly connected to B, so that a connection between a and B is achieved through C. It is also understood that "a-connection B" as described herein may be a direct connection between a and B, or an indirect connection between a and B via one or more other electrical components.

In the description of the present utility model, "/" means "or" unless otherwise indicated, for example, A/B may mean A or B. "and/or" herein is merely an association relationship describing an association object, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone.

In the description of the present utility model, the words "first", "second", etc. are used only to distinguish different objects, and are not limited to numbers and execution orders, and the words "first", "second", etc. are not necessarily different. Furthermore, the terms "comprising," "including," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion.

The technical scheme of the utility model is further described in detail below with reference to the accompanying drawings.

Referring to fig. 1, an embodiment of the present utility model provides a voltage measurement apparatus 10, where the voltage measurement apparatus 10 can be used to measure a voltage value of a signal of a circuit 20 to be measured. For example, the voltage value of the signal on a certain line of the circuit 20 to be tested is measured, and compared with a preset reference value to evaluate whether the signal quality of the circuit 20 to be tested meets the requirement. The signal may be a single-way signal or a two-way signal, e.g., a two-way signal may refer to a differential signal.

The circuit 20 to be tested may be a circuit in an electronic device, and the electronic device may be a mobile phone, a tablet computer, a television, a notebook computer, etc., which is not limited in type according to the embodiment of the present utility model.

The voltage measurement apparatus 10 may include a signal processing circuit 101, an adjustable voltage dividing circuit 102, an adjustable gain circuit 103, an analog-to-digital conversion circuit 104, and a main control circuit 105.

The signal processing circuit 101 is configured to receive a signal to be tested output by the circuit to be tested 20, and process the signal to be tested to obtain a signal to be tested with a positive voltage. For example, the signal processing circuit 101 may process a signal to be tested through an operational amplifier to obtain a signal to be tested with a positive voltage, and the signal processing circuit 101 may include an operational amplifier supporting a single input and a differential signal input. For example, the model of the operational amplifier is INA597. If the signal to be measured is a single-channel signal and the level is positive, adopting a single-channel signal input mode, wherein the positive input end (IN+) of the operational amplifier is used for receiving the signal to be measured, the negative input end (IN-) of the operational amplifier is grounded, and the output of the operational amplifier is a positive voltage signal; if the signal to be detected is a single-channel signal and the level is negative, adopting a single-channel input mode, connecting the positive input end of the operational amplifier to the ground, and using the negative input end (IN-) of the operational amplifier to receive the signal to be detected, wherein the output of the operational amplifier is a positive voltage signal; if the signal to be detected is a differential signal, a two-way signal input mode is adopted, the positive input end of the operational amplifier is used for receiving a positive signal of the differential signal, the negative input end of the operational amplifier is used for receiving a negative signal of the differential signal, and the output of the operational amplifier is a positive voltage signal. Through the above electric connection mode, as the output of the operational amplifier is positive voltage signals, the post-stage circuits of the operational amplifier can adopt a simple positive voltage power supply mode, thereby simplifying the circuit design and reducing the cost.

In some embodiments, the signal processing circuit 101 may further perform amplification processing, or perform reduction processing, or perform neither amplification processing nor reduction processing on the signal to be tested, which is not limited by the embodiment of the present utility model. The signal to be tested is processed through the operational amplifier to obtain the signal to be tested with positive voltage, and the gain of the operational amplifier can be set according to actual requirements, so that the utility model is not limited to the method.

The adjustable voltage dividing circuit 102 is electrically connected to the signal processing circuit 101, the adjustable gain circuit 103 and the master control circuit 105, and the adjustable voltage dividing circuit 102 is configured to set a voltage dividing ratio according to a first control signal output by the master control circuit 105 and divide a signal to be detected output by the signal processing circuit 101 based on the set voltage dividing ratio. For example, the adjustable voltage dividing circuit 102 may include a resistor voltage dividing network supporting various voltage dividing combinations, the master circuit 105 may set a voltage dividing ratio of the resistor voltage dividing network by outputting a first control signal, or the adjustable voltage dividing circuit 102 may include a plurality of voltage dividing branches having different voltage dividing ratios, and the master circuit 105 may select a certain voltage dividing branch to be connected between the signal processing circuit 101 and the adjustable gain circuit 103 by outputting the first control signal.

The adjustable gain circuit 103 is electrically connected to the main control circuit 105, and the adjustable gain circuit 103 is configured to set a gain according to a second control signal output by the main control circuit 105, and amplify the signal to be measured output by the adjustable voltage divider circuit 102 according to the set gain. For example, the adjustable gain circuit 103 may include a gain amplifier capable of performing gain adjustment and an adjustable resistor network, the adjustable resistor network is used as a gain resistor connected to the gain amplifier, the gain of the gain amplifier is changed by changing the gain resistor, and the main control circuit 105 may set the resistance value of the adjustable resistor network through the second control signal, thereby setting the gain of the gain amplifier.

The voltage regulation network is formed by the adjustable gain circuit 103 and the adjustable voltage division circuit 102, so that the voltage fine adjustment is realized to meet the input voltage requirement of the analog-to-digital conversion circuit 104 at the subsequent stage. For example, the resistor divider network supports 5 voltage dividers, the gain resistor network supports 4 gains, and the two stages of the resistor network can support 20 voltage combinations, so that the requirement of wide voltage measurement can be realized through the cooperation of the adjustable gain circuit 103 and the adjustable voltage divider circuit 102.

The analog-to-digital conversion circuit 104 is electrically connected between the adjustable gain circuit 103 and the main control circuit 105, and the analog-to-digital conversion circuit 104 is used for performing analog-to-digital conversion on the signal to be detected output by the adjustable gain circuit 103 to obtain a digital signal, and inputting the digital signal to the main control circuit 105. The main control circuit 105 is used for determining the voltage value of the signal to be measured according to the digital signal converted by the analog-to-digital conversion circuit 104.

In some embodiments, the master circuit 105 may process the digital signal using an existing analysis algorithm to obtain a voltage value of the signal to be measured. For a signal to be measured with positive level, the voltage value of the obtained signal to be measured is positive, for a signal to be measured with negative level, the voltage value of the obtained signal to be measured is negative, and for a signal to be measured, the voltage difference value between the differential signals is obtained. The voltage value of the signal to be measured can be transmitted to other devices with display screens by the main control circuit 105 for display, or the voltage measuring device 10 can be integrated with a display screen module, and the main control circuit 105 can transmit the voltage value of the signal to be measured to the display screen module for display.

In some embodiments, the voltage measurement device 10 may be communicatively connected to an upper computer, for example, may be connected to the upper computer through a USB interface or an RS232 interface, and a tester may estimate a voltage value of a signal to be measured and send a setting command to the main control circuit 105 through the upper computer, so that the main control circuit 105 may output a corresponding first control signal and a corresponding second control signal to set a proper voltage division ratio and a proper gain.

Referring to fig. 2, a voltage measurement apparatus 10 according to another embodiment of the present utility model is provided, and compared to fig. 1, the voltage measurement apparatus 10 may further include an electronic switch gating circuit 106.

The signal processing circuit 101 is electrically connected between the electronic switch gating circuit 106 and the adjustable voltage divider circuit 102. The electronic switch gating circuit 106 is configured to receive the signal to be tested output by the circuit to be tested 20, and transmit the signal to be tested to the signal processing circuit 101 to process the signal to be tested to obtain a signal to be tested with a positive voltage. The electronic switch gating circuit 106 may be set to a single channel input or a dual channel input according to the third control signal output from the main control circuit 105. For example, the electronic switch gating circuit 106 may include an electronic switch, and the tester may send a setting instruction to the main control circuit 105 through the host computer according to the type of the signal to be tested, so that the main control circuit 105 may output a corresponding third control signal to be set as a single-channel input or a dual-channel input. The signal to be measured is a single-channel signal, the electronic switch gating circuit 106 is set to a single-channel input, the signal to be measured is a two-channel signal, and the electronic switch gating circuit 106 is set to a two-channel input.

The signal processing circuit 101 may support single-ended input processing and double-ended input processing, and the signal processing circuit 101 is further electrically connected to the main control circuit 105 and is further configured to set the single-ended input processing or the double-ended input processing according to a fourth control signal output by the main control circuit 105. For example, the signal to be measured is a single-channel signal, the electronic switch gating circuit 106 is set to a single-channel input, the signal processing circuit 101 is correspondingly set to a single-ended input process, the signal to be measured is a two-channel signal, the electronic switch gating circuit 106 is set to a two-channel input, and the signal processing circuit 101 is correspondingly set to a double-ended input process.

If the signal to be measured is a single-channel signal, the main control circuit 105 analyzes the voltage value of the signal to be measured according to the digital signal converted by the analog-to-digital conversion circuit 104. If the signal to be measured is a two-way signal, the voltage difference between the two-way signal is obtained by the main control circuit 105 according to the digital signal converted by the analog-to-digital conversion circuit 104, i.e. for the differential signal, the voltage measurement device 10 provided in the embodiment of the present utility model can measure the voltage difference between the differential signals, and if the voltage value of each way of signal (positive signal and negative signal) in the differential signal needs to be measured, the voltage values can be measured respectively by a single-channel input mode.

As shown in fig. 2, the adjustable gain circuit 103 may include a gain amplifying unit 1031 and an adjustable resistance unit 1032. The gain amplifying unit 1031 includes a first input terminal, a second input terminal, a first gain adjusting terminal, a second gain adjusting terminal, and an output terminal. The first input terminal of the gain amplification unit 1031 is electrically connected to the adjustable voltage division circuit 102, the second input terminal of the gain amplification unit 1031 is grounded, and the output terminal of the gain amplification unit 1031 is electrically connected to the analog-to-digital conversion circuit 104. The adjustable resistor unit 1032 includes a first end, a second end and a control end, the first end of the adjustable resistor unit 1032 is electrically connected to the first gain adjustment end of the gain amplifying unit 1031, the second end of the adjustable resistor unit 1032 is electrically connected to the second gain adjustment end of the gain amplifying unit 1031, the control end of the adjustable resistor unit 1032 is electrically connected to the main control circuit 105, and the adjustable resistor unit 1032 can set the impedance connected between the first gain adjustment end and the second gain adjustment end according to the second control signal output by the main control circuit 105.

Referring to fig. 3, a circuit diagram of a voltage measurement device 10 according to an embodiment is provided.

The master control circuit 105 may include a chip with control and signal processing capabilities, such as an MCU, or a single-chip microcomputer. Fig. 3 illustrates an example in which the master circuit 105 includes an MCU U0, for example, the MCU U0 may be an MCU chip based on Arm Cortex-M and RISC-V cores. The electronic switch gating circuit 106 may include an electronic gating switch S1, and the electronic gating switch S1 may be set to a single channel input or a dual channel input according to a control signal output by the MCU U0. The electronic gating switch S1 may include at least two input terminals, a first output terminal, a second output terminal, and at least one control terminal (fig. 3 illustrates 3 control terminals ct1, ct2, and ct3, but not limited thereto), the input terminal of the electronic gating switch S1 may be used for receiving a signal to be tested, and the control terminal of the electronic gating switch S1 may be connected to a general-purpose input/output (GPIO) pin of the MCU U0 to receive a control signal output by the MCU U0. The electronic gating switch S1 may be a TMUX7209 chip, and the electronic gating switch S1 may also select other multiplexer chips with low leakage current and small on internal resistance, which is not limited by the embodiment of the present utility model.

The signal processing circuit 101 may include a first electronic switch S2, a second electronic switch S3, and a first operational amplifier U1. The first electronic switch S2 includes a first input terminal, a second input terminal, an output terminal, and a control terminal. The first input end of the first electronic switch S2 is grounded, the second input end of the first electronic switch S2 is electrically connected to the first output end of the electronic gating switch S1, and the control end (e.g., the control end ct4 illustrated in fig. 3) of the first electronic switch S2 is electrically connected to the MCU U0. The second electronic switch S3 includes a first input terminal, a second input terminal, an output terminal, and a control terminal. The first input end of the second electronic switch S3 is grounded, the second input end of the second electronic switch S3 is electrically connected to the second output end of the electronic gating switch S1, and the control end (e.g., the control end ct5 illustrated in fig. 3) of the second electronic switch S3 is electrically connected to the MCU U0. The first operational amplifier U1 includes a positive input terminal, a negative input terminal, and an output terminal. The positive input end of the first operational amplifier U1 is electrically connected to the output end of the first electronic switch S2, the negative input end of the first operational amplifier U1 is electrically connected to the output end of the second electronic switch S3, and the output end of the first operational amplifier U1 is electrically connected to the adjustable voltage divider 102. The first operational amplifier U1 may be an INA597 chip, and the first operational amplifier U1 may also be any other type of operational amplifier chip. The control ends of the first electronic switch S2 and the second electronic switch S3 may be respectively connected with the GPIO pin of the MCU U0, so as to receive the control signal output by the MCU U0.

The adjustable voltage divider 102 may include a first resistor R1, a plurality of voltage dividing resistors RA1 to RAn (which may have different resistance values), and a third electronic switch S4. One end of the first resistor R1 is electrically connected to the output end of the first operational amplifier U1, and the other end of the first resistor R1 is electrically connected to the adjustable gain circuit 103. One end of each of the plurality of voltage dividing resistors RA1 to RAn is electrically connected to the other end of the first resistor R1. The third electronic switch S4 includes a plurality of input ends, an output end and a plurality of control ends (fig. 3 illustrates 3 control ends ct6, ct7 and ct8, but not limited thereto), each of the plurality of input ends of the third electronic switch S4 is electrically connected to the other end of each of the voltage dividing resistors RA1 to RAn in a one-to-one correspondence manner, the output end of the third electronic switch S4 is grounded, and the plurality of control ends of the third electronic switch S4 are electrically connected to the MCU U0. For example, each control end of the third electronic switch S4 may be connected to a GPIO pin of the MCU U0, so as to receive a control signal output by the MCU U0, and the first resistor R1 and each voltage dividing resistor RA1 to RAn may select a resistor with higher resistance precision, so as to improve the measurement accuracy, for example, the resistance precision may be up to 0.1% or higher.

In some embodiments, the plurality of voltage dividing resistors RA1 to RAn and the third electronic switch S4 may be replaced by a digital potentiometer (programmable resistor).

The adjustable gain circuit 103 may include a gain amplifier U2, a plurality of second resistors R2-Rm (which may have different resistance values), and a fourth electronic switch S5. The gain amplifier U2 includes a positive input terminal, a negative input terminal, a first gain adjustment terminal, a second gain adjustment terminal, and an output terminal. The positive input end of the gain amplifier U2 is electrically connected to the other end of the first resistor R1, the negative input end of the gain amplifier U2 is grounded, and the output end of the gain amplifier U2 is electrically connected to the analog-to-digital conversion circuit 104. One end of each of the plurality of second resistors R2 to Rm is electrically connected to the first gain adjustment end of the gain amplifier U2. The fourth electronic switch S5 includes a plurality of input ends, an output end and a plurality of control ends (fig. 3 illustrates 3 control ends ct9, ct10, ct11, but not limited thereto), each of the plurality of input ends of the fourth electronic switch S5 is electrically connected to the other end of each of the second resistors R2 to Rm in a one-to-one correspondence manner, the output end of the fourth electronic switch S5 is electrically connected to the second gain adjusting end of the gain amplifier U2, and the plurality of control ends of the fourth electronic switch S5 are electrically connected to the MCU U0. For example, each control terminal of the fourth electronic switch S5 may be connected to a GPIO pin of the MCU U0, so as to receive a control signal output by the MCU U0. Each of the second resistors R2 to Rm may select a resistor having a higher resistance accuracy to improve the measurement accuracy, for example, the resistance accuracy may be 0.1% or higher.

In some embodiments, the plurality of second resistors R2 to Rm and the fourth electronic switch S5 may be replaced by a digital potentiometer (programmable resistor).

The analog-to-digital conversion circuit 104 may include an analog-to-digital converter (ADC) U3, and the MCU U0 may receive the digital signal input by the analog-to-digital converter U3 through an SPI, I2C, or the like bus. The analog-digital converter U3 can select analog-digital converter chips with different precision supporting single-ended input according to the measurement precision requirement, for example, a low-precision requirement can select 12-Bit analog-digital converter chip, the model can be ADS8665 or ADS7951, a high-precision requirement can select 18-Bit or higher-resolution analog-digital converter chip, and the model can be ADS8699 or other higher-Bit analog-digital conversion chips.

In the actual measurement process, the electronic gating switch S1 may be firstly communicated with the MCU U0 through the upper computer (the signal to be measured is not connected to the voltage measurement device 10), the processing mode of the signal processing circuit 101 (single-ended input processing or double-ended input processing), the voltage division ratio of the adjustable voltage division circuit 102, the gain of the adjustable gain circuit 103 are set, then the electronic gating switch S1 (single-channel input or double-channel input) is turned on, the signal to be measured is connected to the voltage measurement device 10, and the MCU U0 analyzes to obtain the voltage value of the signal to be measured or the voltage difference between the differential signals.

In some embodiments, the analog-to-digital converter U3 may be integrated in the MCU U0, or may be an analog-to-digital conversion chip independent of the MCU U0, which is not limited in the present utility model.

Other corresponding changes and modifications will occur to those skilled in the art from the present disclosure and the application conception and the practical need for production, and are intended to be within the scope of the present disclosure.

Claims (10)

1. The voltage measuring device is characterized by comprising a signal processing circuit, an adjustable voltage dividing circuit, an adjustable gain circuit, an analog-to-digital conversion circuit and a main control circuit;

the signal processing circuit is used for receiving a signal to be detected output by the circuit to be detected and processing the signal to be detected to obtain a signal to be detected of positive voltage;

the adjustable voltage dividing circuit is respectively and electrically connected with the signal processing circuit, the adjustable gain circuit and the main control circuit, and is used for setting a voltage dividing ratio according to a first control signal output by the main control circuit and dividing a signal to be detected output by the signal processing circuit based on the set voltage dividing ratio;

the adjustable gain circuit is electrically connected to the main control circuit and is used for setting the gain according to a second control signal output by the main control circuit and amplifying a signal to be detected output by the adjustable voltage dividing circuit according to the set gain;

the analog-to-digital conversion circuit is electrically connected between the adjustable gain circuit and the main control circuit, and is used for performing analog-to-digital conversion on a signal to be detected output by the adjustable gain circuit to obtain a digital signal, and inputting the digital signal to the main control circuit;

the main control circuit is used for determining the voltage value of the signal to be detected according to the digital signal converted by the analog-to-digital conversion circuit.

2. The voltage measurement device of claim 1, further comprising an electronic switch gating circuit electrically connected between the circuit under test and the signal processing circuit and further electrically connected to the master control circuit, the electronic switch gating circuit configured to set a single channel input or a dual channel input according to a third control signal output from the master control circuit.

3. The voltage measurement apparatus of claim 2, wherein the signal processing circuit is further configured to set a single-ended input process or a double-ended input process according to a fourth control signal output from the main control circuit.

4. The voltage measurement device of claim 2, wherein if the signal to be measured is a differential signal, the electronic switch gating circuit is configured to set the third control signal output by the master circuit to the dual-channel input, and the master circuit is configured to determine a voltage difference between the differential signals according to the digital signal converted by the analog-to-digital conversion circuit.

5. The voltage measurement device of claim 3 wherein the signal processing circuit comprises:

the first electronic switch comprises a first input end, a second input end, an output end and a control end, wherein the first input end of the first electronic switch is grounded, the second input end of the first electronic switch is electrically connected with the first output end of the electronic switch gating circuit, and the control end of the first electronic switch is electrically connected with the main control circuit;

the second electronic switch comprises a first input end, a second input end, an output end and a control end, wherein the first input end of the second electronic switch is grounded, the second input end of the second electronic switch is electrically connected with the second output end of the electronic switch gating circuit, and the control end of the second electronic switch is electrically connected with the main control circuit;

the first operational amplifier comprises a positive input end, a negative input end and an output end, wherein the positive input end of the first operational amplifier is electrically connected with the output end of the first electronic switch, the negative input end of the first operational amplifier is electrically connected with the output end of the second electronic switch, and the output end of the first operational amplifier is electrically connected with the adjustable voltage dividing circuit.

6. The voltage measurement apparatus of claim 1, wherein the adjustable voltage dividing circuit comprises a plurality of voltage dividing branches with different voltage dividing ratios, and the adjustable voltage dividing circuit is configured to select a voltage dividing branch to be connected between the signal processing circuit and the adjustable gain circuit according to the first control signal output from the main control circuit.

7. The voltage measurement apparatus of claim 6 wherein the adjustable voltage divider circuit comprises:

one end of the first resistor is electrically connected with the signal processing circuit, and the other end of the first resistor is electrically connected with the adjustable gain circuit;

one end of each of the plurality of voltage dividing resistors is electrically connected to the other end of the first resistor;

the third electronic switch comprises a plurality of input ends, output ends and a plurality of control ends, each input end of the plurality of input ends of the third electronic switch is electrically connected to the other end of each voltage dividing resistor in a one-to-one correspondence mode, the output end of the third electronic switch is grounded, and the plurality of control ends of the third electronic switch are electrically connected to the main control circuit.

8. The voltage measurement apparatus of claim 1 wherein the adjustable gain circuit comprises:

the gain amplifier comprises a positive input end, a negative input end, a first gain adjusting end, a second gain adjusting end and an output end, wherein the positive input end of the gain amplifier is electrically connected with the adjustable voltage dividing circuit, the negative input end of the gain amplifier is grounded, and the output end of the gain amplifier is electrically connected with the analog-to-digital conversion circuit;

the adjustable resistor unit comprises a first end, a second end and a control end, wherein the first end of the adjustable resistor unit is electrically connected with the first gain adjusting end of the gain amplifier, the second end of the adjustable resistor unit is electrically connected with the second gain adjusting end of the gain amplifier, the control end of the adjustable resistor unit is electrically connected with the main control circuit, and the adjustable resistor unit is used for setting impedance connected between the first gain adjusting end and the second gain adjusting end according to a second control signal output by the main control circuit.

9. The voltage measurement device of claim 8, wherein the adjustable resistance unit comprises:

a plurality of second resistors, wherein one end of each second resistor in the plurality of second resistors is electrically connected to a first gain adjustment end of the gain amplifier;

the fourth electronic switch comprises a plurality of input ends, output ends and a plurality of control ends, each input end in the plurality of input ends of the fourth electronic switch is electrically connected to the other end of each second resistor in a one-to-one correspondence mode, the output end of the fourth electronic switch is electrically connected to the second gain adjusting end of the gain amplifier, and the plurality of control ends of the fourth electronic switch are electrically connected to the main control circuit.

10. The voltage measurement device of claim 1, wherein the analog-to-digital conversion circuit comprises an analog-to-digital converter, and the master control circuit comprises a micro control unit, and the micro control unit receives the digital signal input by the analog-to-digital converter through an SPI bus or an I2C bus.