Circuit capable of realizing voltage isolation linear remote measurement and working method thereof

Abstract

The invention relates to a circuit capable of realizing voltage isolation linear remote measurement and a working method thereof. The circuit comprises a power supply unit, a telemetering voltage acquisition unit, a voltage isolation conversion unit and a telemetering voltage output unit. The output end of the power supply unit is connected with the input end of the telemetering voltage acquisition unit, the output end of the telemetering voltage acquisition unit is connected with the input end of the voltage isolation conversion unit, and the output end of the voltage isolation conversion unit is connected with the input end of the telemetering voltage output unit. The circuit can be applied to power supply equipment, realizes various voltage isolation linear telemetering functions, and has the advantages of simple circuit structure and low cost. The innovation point of the invention lies in that the mode of combining the linear optocoupler and the operational amplifier is adopted, and the isolation characteristic of the linear optocoupler and the characteristic that the secondary current is equal are utilized to realize voltage isolation linear telemetering. The method can be effectively applied to the field of high-reliability power supplies such as spaceflight and military industry, and has important use value in the fields of power supply monitoring and remote sensing.

Description

Technical Field

[0001] The invention relates to the technical field of electronic equipment power supply system, and in particular to a circuit capable of realizing voltage isolation linear telemetry and a working method thereof. Background Art

[0002] As the complexity of military and aerospace power supply systems continues to increase, it is critical to ensure the safe and reliable operation of power supply equipment. The introduction of telemetry functions makes real-time monitoring and protection possible, and isolated sampling technology is one of the key means to ensure system stability and safety.

[0003] In a high voltage environment, isolation can effectively prevent the high voltage side from interfering with or damaging the low voltage control circuit, thus avoiding potential safety risks. Isolation helps reduce the impact of electromagnetic interference (EMI) and other electrical noise, ensuring the accuracy and stability of data acquisition. Linear isolated telemetry can provide more accurate voltage measurement, which is especially important for power systems that require strict control and regulation. In some occasions with extremely high accuracy requirements, such as the aerospace field, linear isolated telemetry can provide more reliable performance.

[0004] In military and aerospace power supply systems, although linear isolation telemetry technology provides many advantages, it also has some shortcomings and technical problems. High-performance linear isolation devices (such as optocouplers, digital isolators, etc.) are usually expensive, which increases the overall cost of the system and limits its widespread application in certain budget-limited applications. Traditional isolation devices (such as transformers and optocouplers) are often large and difficult to integrate into compact designs. For space-constrained environments such as avionics, this can become a bottleneck. Summary of the invention

[0005] The purpose of the present invention is to provide a voltage-isolated linear telemetry circuit and a working method thereof, which can solve the deficiencies in the prior art and realize the voltage-isolated linear telemetry function by using linear optocouplers, operational amplifiers and other resistor-capacitor devices.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect of the present invention, a circuit capable of realizing voltage isolation linear telemetry is disclosed. The circuit comprises a power supply unit, a telemetry voltage acquisition unit, a voltage isolation conversion unit and a telemetry voltage output unit.

[0008] The output end of the power supply unit is connected to the input end of the telemetry voltage acquisition unit, the output end of the telemetry voltage acquisition unit is connected to the input end of the voltage isolation conversion unit, and the output end of the voltage isolation conversion unit is connected to the input end of the telemetry voltage output unit. The power supply unit is used to supply power to the telemetry voltage acquisition unit. The telemetry voltage acquisition unit is used to collect telemetry voltage. The input end of the voltage isolation conversion unit is used to receive the telemetry voltage collected by the telemetry voltage acquisition unit.

[0009] As a further improvement of the above technical solution, the power supply unit includes a resistor R0, a voltage regulator D0, a transistor T0, a capacitor C0 and a power supply V1. The first end of the resistor R0 is connected to the positive end V1+ of the power supply V1 and the collector of the transistor T0, and the second end of the resistor R0 is connected to the cathode of the voltage regulator D0 and the base of the transistor T0; the anode of the voltage regulator D0 is connected to the ground end V1-GND of the power supply V1 and the first end of the capacitor C0; the emitter of the transistor T0 is connected to the second end of the capacitor C0; the emitter of the transistor T0 serves as the output end of the power supply unit, and the output of the output end is the output voltage VCC.

[0010] As a further improvement of the above technical solution, the telemetry voltage acquisition unit includes a resistor R1, a resistor R2, a resistor R3 and an operational amplifier T1; the first end of the resistor R1 is connected to the positive end V1+ of the power supply V1, and the second end is connected to the in-phase input end of the operational amplifier T1 and the first end of the resistor R2; the second end of the resistor R2 is connected to the ground end GND of the power supply V1 and the first end of the resistor R3; the second end of the resistor R3 is connected to the inverting input end of the operational amplifier T1; the output end of the operational amplifier T1 is connected to the input end of the voltage isolation conversion unit; the positive power supply end of the operational amplifier T1 is connected to the output voltage VCC output by the output end of the power supply unit, and the negative power supply end of the operational amplifier T1 is connected to the ground end V1-GND of the power supply V1.

[0011] As a further improvement of the above technical solution, the voltage isolation conversion unit includes a resistor R4, a capacitor C4 and a linear optocoupler T2; the linear optocoupler T2 includes a light emitting diode, a first secondary phototransistor and a second secondary phototransistor. The first end of the resistor R4 is connected to the output end of the remote voltage acquisition unit, and the second end of the resistor R4 is connected to the anode of the light emitting diode in the linear optocoupler T2. The first end of the capacitor C4 is connected to the output end of the remote voltage acquisition unit, and the second end of the capacitor C4 is connected to the inverting input end of the operational amplifier T1 in the remote voltage acquisition unit; the cathode of the light emitting diode of the linear optocoupler T2 is grounded; the collector of the first secondary phototransistor of the linear optocoupler T2 is connected to the inverting input end of the operational amplifier T1 in the remote voltage acquisition unit, and the emitter of the first secondary phototransistor of the linear optocoupler T2 is connected to the positive power supply end of the operational amplifier T1.

[0012] As a further improvement of the above technical solution, it includes a resistor R5, an operational amplifier T3 and a power supply V2; the first end of the resistor R5 is connected to the collector of the second secondary phototransistor of the linear optocoupler T2 and the in-phase input end of the operational amplifier T3, and the second end of the resistor R5 is grounded V2-GND; the inverting input end of the operational amplifier T3 is connected to the output end of the operational amplifier T3, the positive power supply end of the operational amplifier T3 is connected to the positive end V2+ of the power supply V2, and the negative power supply end of the operational amplifier T3 is connected to the ground end V2-GND of the power supply V2; the power supply V2+ is connected to the emitter of the second secondary phototransistor of the linear optocoupler T2 and the positive end V2+ of the power supply V2.

[0013] As a further improvement of the above technical solution, the power source V1 and the power source V2 are isolated from each other.

[0014] In a second aspect of the present invention, a method for operating the above-mentioned circuit capable of realizing voltage isolation linear telemetry is disclosed. The method comprises the following steps:

[0015] S1, the power supply unit is powered by the power supply V1, and the base voltage of the transistor T0 is maintained at the working voltage V0 of the transistor D0 through the resistor R0 and the voltage regulator D0. The emitter voltage of the transistor T0 is the output voltage VCC of the power supply unit.

[0016] S2 and the operational amplifier T1 are powered by the output voltage VCC of the power supply unit; the measured voltage V1 is divided by resistors R1 and R2 and connected to the non-inverting input terminal of the operational amplifier T1; the inverting input terminal of the operational amplifier T1 is connected to the measured voltage V1-GND through resistor R3, and the output terminal of the operational amplifier T1 is connected to the anode of the light-emitting diode of the linear optocoupler T2 through the current-limiting resistor R4; it can be known from the working characteristics of the operational amplifier that the input terminal voltage of the operational amplifier T1 is VT1IN=V1*R2 / (R1+R2), and the operational amplifier T1 outputs a high level.

[0017] S3, the output of the operational amplifier T1 is connected to the anode of the light-emitting diode of the linear optocoupler T2 through the current-limiting resistor R4, the light-emitting diode works, and the two phototransistors of the secondary of the linear optocoupler T2 are turned on.

[0018] S4, voltage V3 is connected to the inverting input terminal of operational amplifier T1 through the first secondary phototransistor of linear optocoupler T2; voltage V2 is connected to ground through the second secondary phototransistor of linear optocoupler T2 and resistor R5. From the working characteristics of linear optocoupler, it can be seen that the currents generated by the two secondary circuits of linear optocoupler T2 are equal, I1=I2=VT1IN / R3=V1*R2 / (R1+R2) / R3.

[0019] S5, the non-inverting input terminal of the operational amplifier T3 is connected to the voltage divider on the resistor R5, and the inverting input terminal is connected to the output of the operational amplifier T3 to form a voltage follower. The voltage at the non-inverting input terminal of the operational amplifier T3 is VT2IN=I2*R5=V1*R2 / (R1+R2) / R3*R5. From the working characteristics of the operational amplifier, it can be seen that the output voltage VOUT of the operational amplifier T3 is VT2IN=I2*R5=V1*R2 / (R1+R2) / R3*R5. By configuring the above parameters reasonably, the isolated linear remote sensing of the measured voltage V1 can be realized.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] The voltage-isolated linear telemetry circuit of the present invention can be applied to power supply equipment to realize various voltage-isolated linear telemetry functions, and has the advantages of simple circuit structure and low cost. The innovation of the present invention is to use a combination of a linear optocoupler and an operational amplifier, and utilize the isolation characteristics of the linear optocoupler and the secondary current equality characteristics to realize voltage-isolated linear telemetry. The present invention can be effectively applied to high-reliability power supply fields such as aerospace and military industries, and has important use value in the fields of power supply monitoring and remote sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a principle block diagram of a voltage-isolated linear telemetry circuit that can be implemented in the present invention;

[0023] Figure 2 The circuit schematic diagram of the voltage isolation linear telemetry circuit implemented in the present invention.

[0024] in:

[0025] 1. Power supply unit, 2. Voltage telemetry acquisition unit, 3. Voltage isolation conversion unit, 4. Telemetry voltage output unit. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings:

[0027] like Figure 1 A voltage-isolated linear telemetry circuit is shown, which includes a power supply unit 1, a telemetry voltage acquisition unit 2, a voltage isolation conversion unit 3, and a telemetry voltage output unit 4. The output end of the power supply unit 1 is connected to the input end of the telemetry voltage acquisition unit 2, the output end of the telemetry voltage acquisition unit 2 is connected to the input end of the voltage isolation conversion unit 3, and the output end of the voltage isolation conversion unit 3 is connected to the input end of the telemetry voltage output unit 4.

[0028] The circuit structure proposed by the present invention is simple and low-cost, and is suitable for occasions requiring high reliability, such as power supply monitoring and remote sensing applications in the aerospace and military fields. By combining a linear optocoupler and an operational amplifier, an effective voltage isolation linear telemetry function is achieved. The power supply unit 1 is used to power the telemetry voltage acquisition unit 2. The telemetry voltage acquisition unit 2 is used to collect the telemetry voltage. The input end of the voltage isolation conversion unit 3 is used to receive the telemetry voltage collected by the telemetry voltage acquisition unit 2. The telemetry voltage output unit 4 is used to receive a signal from the voltage isolation conversion unit and convert it into a readable output voltage.

[0029] like Figure 2As shown, the power supply unit 1 includes a resistor R0, a voltage regulator D0, a transistor T0, a capacitor C0 and a power supply V1. The first end of the resistor R0 is connected to the positive end V1+ of the power supply V1 and the collector of the transistor T0, and the second end of the resistor R0 is connected to the cathode of the voltage regulator D0 and the base of the transistor T0; the anode of the voltage regulator D0 is connected to the ground end V1-GND of the power supply V1 and the first end of the capacitor C0; the emitter of the transistor T0 is connected to the second end of the capacitor C0; the emitter of the transistor T0 serves as the output end of the power supply unit, and the output of the output end is the output voltage VCC. VI+ in the power supply unit 1 is the voltage to be telemetered. The power supply circuit formed by the voltage regulator D0 and the transistor T0 can directly power the operational amplifier and the entire telemetering acquisition unit. In this way, directly taking power from the voltage to be telemetered can simplify the power supply design of the functional circuit and reduce the burden of the application system level.

[0030] like Figure 2 As shown, the telemetry voltage acquisition unit 2 includes a resistor R1, a resistor R2, a resistor R3 and an operational amplifier T1; the first end of the resistor R1 is connected to the positive end V1+ of the power supply V1, and the second end is connected to the in-phase input end of the operational amplifier T1 and the first end of the resistor R2; the second end of the resistor R2 is connected to the ground end GND of the power supply V1 and the first end of the resistor R3; the second end of the resistor R3 is connected to the inverting input end of the operational amplifier T1; the output end of the operational amplifier T1 is connected to the input end of the voltage isolation conversion unit 3; the positive power supply end of the operational amplifier T1 is connected to the output voltage VCC output by the output end of the power supply unit 1, and the negative power supply end of the operational amplifier T1 is connected to the ground end V1-GND of the power supply V1. The telemetry voltage acquisition unit 2 is used to linearly acquire the telemetry voltage. The telemetry voltage is divided by a voltage divider resistor and then input into the in-phase input end of the operational amplifier. According to the virtual short characteristic of the operational amplifier, the voltage of the inverting input end of the operational amplifier is ensured to always be equal to the divided value of the telemetry voltage.

[0031] like Figure 2As shown, the voltage isolation conversion unit 3 includes a resistor R4, a capacitor C4 and a linear optocoupler T2; the linear optocoupler T2 includes a light emitting diode, a first secondary phototransistor and a second secondary phototransistor. The first end of the resistor R4 is connected to the output end of the remote voltage acquisition unit 2, and the second end of the resistor R4 is connected to the anode of the light emitting diode in the linear optocoupler T2. The first end of the capacitor C4 is connected to the output end of the remote voltage acquisition unit 2, and the second end of the capacitor C4 is connected to the inverting input end of the operational amplifier T1 in the remote voltage acquisition unit 2; the cathode of the light emitting diode of the linear optocoupler T2 is grounded; the collector of the first secondary phototransistor of the linear optocoupler T2 is connected to the inverting input end of the operational amplifier T1 in the remote voltage acquisition unit 2, and the emitter of the first secondary phototransistor of the linear optocoupler T2 is connected to the positive power supply end of the operational amplifier T1. The voltage isolation conversion unit 3 uses a linear optocoupler T2 to achieve signal conversion and electrical isolation. The linear optocoupler contains a light-emitting diode and two secondary phototransistors, which are used to transmit electrical signals while maintaining electrical isolation, which is very important for preventing interference between different circuits. The light-emitting diode of the linear optocoupler is powered by the output of the operational amplifier of the previous telemetry voltage acquisition unit; one photodiode of the linear optocoupler is powered by VCC and connected in series with resistor R3, so that the voltage change at the inverting input of the op amp directly affects the current on the photodiode, and then feedback affects the current of the light-emitting diode, that is, it affects the current of the other photodiode at the same time. Since the voltage at the inverting input is equal to the voltage at the positive input, that is, the telemetry voltage. In this way, the isolation and conversion of the telemetry voltage is achieved.

[0032] like Figure 2 As shown, the telemetry voltage output unit 4 includes a resistor R5, an operational amplifier T3 and a power supply V2; the first end of the resistor R5 is connected to the collector of the second secondary phototransistor of the linear optocoupler T2 and the in-phase input end of the operational amplifier T3, and the second end of the resistor R5 is grounded to V2-GND; the inverting input end of the operational amplifier T3 is connected to the output end of the operational amplifier T3, the positive power supply end of the operational amplifier T3 is connected to the positive end V2+ of the power supply V2, and the negative power supply end of the operational amplifier T3 is connected to the ground end V2-GND of the power supply V2; the power supply V2+ is connected to the emitter of the second secondary phototransistor of the linear optocoupler T2 and the positive end V2+ of the power supply V2. The telemetry voltage output unit 4 is used to receive the signal from the voltage isolation conversion unit and convert it into a readable output voltage. In the telemetry voltage output unit, the operational amplifier T3 is configured in the form of a voltage follower, which is used to directly output a voltage value proportional to the input to ensure that the output voltage is in a linear relationship with the input voltage, which enhances the quality and stability of the output signal.

[0033] As a further improvement of the above technical solution, power supply V1 and power supply V2 are isolated from each other, which can achieve high voltage and low voltage isolation, digital and analog isolation in signal acquisition and processing, thereby greatly improving the safety and reliability of the system, especially suitable for aerospace and military industries with extremely high safety requirements.

[0034] The working principle of the voltage-isolated linear telemetry circuit of the present invention is as follows:

[0035] The measured voltage V1 is divided by resistors R1 and R2 and connected to the non-inverting input terminal of the front-stage operational amplifier T1; the inverting input terminal of the operational amplifier T1 is connected to the ground of the measured voltage through resistor R3, and the output terminal of the operational amplifier T1 is connected to the anode of the light-emitting diode of the linear optocoupler T2 through a current-limiting resistor R4.

[0036] The voltage VCC is connected to the inverting input terminal of the operational amplifier T1 through the first secondary phototransistor of the linear optocoupler T2; the voltage V2 is connected to the ground through the second secondary phototransistor of the linear optocoupler T2 and the resistor R5. The inverting input terminal of the operational amplifier T3 is connected to the voltage divider on the resistor R5, and the inverting input terminal is connected to the output of the operational amplifier T3, forming a voltage follower.

[0037] When the circuit is working, the input voltage VT1IN of the operational amplifier T1 is:

[0038] VT1IN=V1*R2 / (R1+R2);

[0039] The current I1 on the first secondary phototransistor of the linear optocoupler T2 is:

[0040] I1=VT1IN / R3=V1*R2 / (R1+R2) / R3;

[0041] The current I2 on the second secondary phototransistor of the linear optocoupler T2 is:

[0042] I2=*I1=VT1IN / R3=V1*R2 / (R1+R2) / R3;

[0043] The voltage VT2IN of the non-inverting input terminal of operational amplifier T3 is:

[0044] VT2IN=I2*R5=V1*R2 / (R1+R2) / R3*R5;

[0045] The output voltage Vout at the output terminal of the operational amplifier T3 is:

[0046] Vout=VT2IN=V1*R2 / (R1+R2) / R3*R5;

[0047] The measured voltage V1 shares a common ground with VCC, and V2 is isolated from V1. From the above analysis, it can be seen that the output voltage Vout realizes the linear isolation remote measurement of the measured voltage V1.

[0048] The present invention realizes powerful voltage isolation telemetry by carefully selecting and combining basic electronic components (such as resistors, capacitors, triodes, voltage regulators) and complex components (operational amplifiers, linear optocouplers). This design not only simplifies the overall circuit structure, but also reduces the demand for additional special integrated circuits, thereby reducing costs and volume. Among them, the linear optocoupler T2, as a core component, not only realizes the electrical isolation between the primary side and the secondary side, but also ensures the high linearity of signal transmission. Since the currents generated when the two secondary phototransistors of the linear optocoupler are turned on are equal (I1=I2), the voltage conversion on both sides can maintain a linear relationship, thereby improving the accuracy of the telemetry results. The operational amplifier T1 in the telemetry voltage acquisition unit is used to collect the telemetry voltage, and at the same time has feedback regulation capabilities, and cooperates with the linear optocoupler to realize the conversion of voltage model and current signal; while the operational amplifier T3 in the telemetry voltage output unit is configured in the form of a voltage follower, directly outputting a voltage value proportional to the input, and realizing the linear output of the signal.

[0049] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the scope of protection determined by the claims of the present invention.

Claims

1. A circuit capable of realizing voltage isolation linear telemetry, characterized in that: The circuit comprises a power supply unit (1), a remote voltage acquisition unit (2), a voltage isolation conversion unit (3) and a remote voltage output unit (4); The output end of the power supply unit (1) is connected to the input end of the remote voltage acquisition unit (2), the output end of the remote voltage acquisition unit (2) is connected to the input end of the voltage isolation conversion unit (3), and the output end of the voltage isolation conversion unit (3) is connected to the input end of the remote voltage output unit (4).

2. The circuit capable of realizing voltage isolation linear telemetry according to claim 1, characterized in that: The power supply unit (1) comprises a resistor R0, a voltage regulator tube D0, a transistor T0, a capacitor C0 and a power supply V1; The first end of the resistor R0 is connected to the positive end V1+ of the power supply V1 and the collector of the transistor T0, and the second end of the resistor R0 is connected to the cathode of the voltage regulator D0 and the base of the transistor T0; the anode of the voltage regulator D0 is connected to the ground end V1-GND of the power supply V1 and the first end of the capacitor C0; the emitter of the transistor T0 is connected to the second end of the capacitor C0; the emitter of the transistor T0 serves as the output end of the power supply unit (1), and the output of the output end is the output voltage VCC.

3. The circuit capable of realizing voltage isolation linear telemetry according to claim 2, characterized in that: The remote voltage acquisition unit (2) comprises a resistor R1, a resistor R2, a resistor R3 and an operational amplifier T1; The first end of the resistor R1 is connected to the positive end V1+ of the power supply V1, and the second end is connected to the in-phase input end of the operational amplifier T1 and the first end of the resistor R2; the second end of the resistor R2 is connected to the ground end GND of the power supply V1 and the first end of the resistor R3; the second end of the resistor R3 is connected to the inverting input end of the operational amplifier T1; the output end of the operational amplifier T1 is connected to the input end of the voltage isolation conversion unit (3); the positive power supply end of the operational amplifier T1 is connected to the output voltage VCC output by the output end of the power supply unit (1), and the negative power supply end of the operational amplifier T1 is connected to the ground end V1-GND of the power supply V1.

4. The circuit capable of realizing voltage isolation linear telemetry according to claim 3, characterized in that: The voltage isolation conversion unit (3) comprises a resistor R4, a capacitor C4 and a linear optical coupler T2; The linear optocoupler T2 comprises a light emitting diode, a first secondary phototransistor and a second secondary phototransistor; the first end of the resistor R4 is connected to the output end of the remote voltage acquisition unit (2), and the second end of the resistor R4 is connected to the anode of the light emitting diode in the linear optocoupler T2; the first end of the capacitor C4 is connected to the output end of the remote voltage acquisition unit (2), and the second end of the capacitor C4 is connected to the inverting input end of the operational amplifier T1 in the remote voltage acquisition unit (2); the cathode of the light emitting diode of the linear optocoupler T2 is grounded; the collector of the first secondary phototransistor of the linear optocoupler T2 is connected to the inverting input end of the operational amplifier T1 in the remote voltage acquisition unit (2), and the emitter of the first secondary phototransistor of the linear optocoupler T2 is connected to the positive power supply end of the operational amplifier T1.

5. The circuit capable of realizing voltage isolation linear telemetry according to claim 4, characterized in that: The remote sensing voltage output unit (4) comprises a resistor R5, an operational amplifier T3 and a power supply V2; The first end of the resistor R5 is connected to the collector of the second secondary phototransistor of the linear optocoupler T2 and the in-phase input terminal of the operational amplifier T3, and the second end of the resistor R5 is connected to the ground V2-GND; the inverting input terminal of the operational amplifier T3 is connected to the output terminal of the operational amplifier T3, the positive power supply terminal of the operational amplifier T3 is connected to the positive terminal V2+ of the power supply V2, and the negative power supply terminal of the operational amplifier T3 is connected to the ground terminal V2-GND of the power supply V2; the power supply V2+ is connected to the emitter of the second secondary phototransistor of the linear optocoupler T2 and the positive terminal V2+ of the power supply V2.

6. The circuit capable of realizing voltage isolation linear telemetry according to claim 5, characterized in that: The power source V1 and the power source V2 are isolated from each other.

7. The working method of the circuit capable of realizing voltage isolation linear telemetry according to claim 5 or 6, characterized in that: The method comprises the following steps: S1, the power supply unit is powered by the power supply V1, and the base voltage of the transistor T0 is maintained at the working voltage V0 of the voltage regulator D0 through the resistor R0 and the voltage regulator D0, and the emitter voltage of the transistor T0 is the output voltage VCC of the power supply unit; S2, operational amplifier T1 is powered by the output voltage VCC of the power supply unit; the measured voltage V1 is divided by resistors R1 and R2 and connected to the non-inverting input terminal of the operational amplifier T1; the inverting input terminal of the operational amplifier T1 is connected to the measured voltage V1-GND through resistor R3, and the output terminal of the operational amplifier T1 is connected to the anode of the light-emitting diode of the linear optocoupler T2 through the current-limiting resistor R4; the input terminal voltage of the operational amplifier T1 is VT1IN=V1*R2 / (R1+R2), and the operational amplifier T1 outputs a high level; S3, the output of the operational amplifier T1 is connected to the anode of the light-emitting diode of the linear optocoupler T2 through the current-limiting resistor R4, the light-emitting diode works, and the two phototransistors of the secondary of the linear optocoupler T2 are turned on; S4, voltage V3 is connected to the inverting input terminal of operational amplifier T1 through the first secondary phototransistor of linear optocoupler T2; voltage V2 is connected to ground through the second secondary phototransistor of linear optocoupler T2 and resistor R5; the currents generated by the two secondary circuits of linear optocoupler T2 are I1 and I2 respectively, which are equal, that is, I1=I2=VT1IN / R3=V1*R2 / (R1+R2) / R3; S5, the non-inverting input terminal of the operational amplifier T3 is connected to the voltage divider on the resistor R5, and the inverting input terminal is connected to the output of the operational amplifier T3 to form a voltage follower; the voltage at the non-inverting input terminal of the operational amplifier T3 is VT2IN=I2*R5=V1*R2 / (R1+R2) / R3*R5; the voltage at the output terminal of the operational amplifier T3 is VOUT=VT2IN=I2*R5=V1*R2 / (R1+R2) / R3*R5; according to the formula of the output terminal voltage of the operational amplifier T3, by configuring the various circuit parameters in the formula, the isolated linear remote sensing of the measured voltage V1 can be realized.

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