Analog input sampler for isolator, isolator and packaging structure thereof

Abstract

The embodiment of the utility model relates to an analog input sampler for an isolator, the isolator and a packaging structure of the isolator. The analog input sampler comprises an input port, a voltage division circuit, a current bias circuit, a voltage and current conversion circuit and an output port, the voltage division circuit is used for receiving an input analog voltage signal and dividing the analog voltage signal into a reference voltage; the current bias circuit compares the analog voltage signal with a working voltage threshold value and provides bias current for the voltage-current conversion circuit according to a comparison result; and the voltage-current conversion circuit is used for converting the reference voltage into a current signal in linear proportion and outputting the current signal through the output port. According to the technical scheme provided by the embodiment of the utility model, the whole circuit can be controlled to work in a linear amplification state according to an input analog signal value, and an optical coupled isolator can be replaced in situ; and compared with an optical coupled isolator, the optical coupled isolator can be manufactured by adopting an integrated circuit process and has the advantage of high reliability.

Description

Technical Field

[0001] The utility model relates to the technical field of signal processing, in particular to an analog input sampler for an isolator, an isolator and a packaging structure thereof. Background Art

[0002] Isolators have the characteristics of eliminating noise and protecting devices from high voltage hazards, so they are widely used in industrial, automotive, and medical fields. Among them, optocoupler isolators have always been the mainstream choice of isolators due to their low price, light weight, and low power consumption. However, their disadvantages are also obvious, such as low speed, easy aging, and short service life. How to use integrated circuits to achieve isolated transmission of analog signals has become an urgent problem to be solved. Utility Model Content

[0003] In view of the above problems in the prior art, the purpose of the present invention is to provide an analog input sampler and an isolator for an isolator and a packaging structure thereof, which can realize the transmission of analog signals, and the output signal is monotonic with the input signal.

[0004] To achieve the above object, according to one aspect of the utility model, there is provided an analog input sampler for an isolator, comprising an input port, a voltage divider circuit, a current bias circuit, a voltage-current conversion circuit and an output port;

[0005] The input end of the voltage divider circuit is connected to the input port, and is used to receive an input analog voltage signal and divide the analog voltage signal into a reference voltage;

[0006] The current bias circuit is coupled to the voltage-current conversion circuit, and the current bias circuit compares the analog voltage signal with the operating voltage threshold, and provides a bias current to the voltage-current conversion circuit according to the comparison result;

[0007] The voltage-to-current conversion circuit is coupled to the output end of the voltage divider circuit, and based on the bias current, converts the reference voltage into a linearly proportional current signal and outputs the signal through the output port.

[0008] Further, the voltage-to-current conversion circuit includes an operational amplifier and an output transistor;

[0009] The non-inverting input terminal of the operational amplifier is coupled to the output terminal of the voltage divider circuit;

[0010] The gate of the output transistor is coupled to the output terminal of the operational amplifier, and the source is coupled to the inverting input terminal of the operational amplifier;

[0011] The drain of the output transistor is connected to the output port.

[0012] Furthermore, the voltage-current conversion circuit also includes a first resistor;

[0013] The first resistor is connected between the inverting input terminal of the operational amplifier and a first ground terminal.

[0014] Further, the current bias circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor and a third resistor;

[0015] The sources of the first transistor, the second transistor and the third transistor are connected to each other and are used to receive the analog voltage signal;

[0016] The gates of the first transistor, the second transistor and the third transistor are connected to each other and to the drain of the second transistor, and the drain of the third transistor outputs a bias current;

[0017] The fourth transistor and the first transistor are used to provide an operating voltage threshold; the gates of the fourth transistor and the fifth transistor are connected to each other and to the drains of the first transistor and the fourth transistor, and the source of the fourth transistor is connected to the first ground terminal;

[0018] The drain of the fifth transistor is connected to the drain of the second transistor;

[0019] The third resistor is connected between the source of the fifth transistor and the first ground terminal.

[0020] Furthermore, an anti-backflow circuit is provided between the input end of the voltage divider circuit and the input port.

[0021] According to a second aspect of the utility model, an isolator is provided, comprising an input side and an output side, wherein the input side and the output side isolate transmission signals through a coupling transmission circuit;

[0022] The input side includes an isolator input port and an analog input sampler, the isolator input port is connected to the input port of the analog input sampler, the analog input sampler is configured to receive an input analog voltage signal through the isolator input port, and control the working state of the isolator according to the input analog voltage signal; the output side includes an isolator output port for outputting the transmitted signal;

[0023] The input side includes a first ground terminal, the output side includes a second ground terminal, and the first ground terminal and the second ground terminal are isolated from each other;

[0024] Wherein, the analog input sampler is the analog input sampler as described in the first aspect of the utility model.

[0025] Furthermore, the input side also includes a current transmission circuit and an oscillator;

[0026] The current transmission circuit is connected between the analog input sampler and the oscillator, and the output end of the oscillator is connected to the coupling transmission circuit;

[0027] The current transmission circuit is used to control the current transmission of the oscillator according to the current access direction of the oscillator.

[0028] Further, the current transmission circuit includes a sixth transistor, a seventh transistor, an eighth transistor and a ninth transistor;

[0029] The sources of the sixth transistor and the seventh transistor are connected to each other and to the input port of the analog input sampler; the gates of the sixth transistor and the seventh transistor are connected to each other and to the drain of the sixth transistor and the output port of the analog input sampler;

[0030] The gates of the eighth transistor and the ninth transistor are connected to each other and to the drains of the seventh transistor and the eighth transistor, and the sources of the eighth transistor and the ninth transistor are connected to each other and to the first ground terminal.

[0031] Furthermore, the output side also includes a demodulator and an output circuit;

[0032] The demodulator includes a rectifier circuit and a filter circuit connected in series;

[0033] The output circuit is coupled to the output end of the filter circuit;

[0034] The coupling transmission circuit includes a transformer, a primary side of the transformer is coupled to the oscillator, and a secondary side of the transformer is coupled to a rectifier circuit.

[0035] Further, the output circuit includes a triode transistor;

[0036] The base of the triode transistor is connected to the output end of the filter circuit, and the collector of the triode transistor is connected to the isolator output port.

[0037] According to a third aspect of the utility model, there is provided a packaging structure of the isolator as described in the second aspect of the utility model, comprising a first bare chip, a second bare chip, a first pin, a second pin, a third pin and a fourth pin;

[0038] The analog input sampler, oscillator and coupled transmission circuit are arranged on a first bare chip, and the demodulator and output circuit are arranged on a second bare chip;

[0039] The first bare chip and the second bare chip are packaged in the same tube shell, the isolator input port in the first bare chip is connected to the first pin, and the first ground terminal is connected to the second pin; the isolator output port in the second bare chip is connected to the third pin, and the second ground terminal is connected to the fourth pin.

[0040] In summary, the embodiment of the utility model provides an analog input sampler for an isolator, an isolator and its packaging structure, the analog input sampler includes an input port, a voltage divider circuit, a current bias circuit, a voltage-current conversion circuit and an output port; the input end of the voltage divider circuit is connected to the input port, for receiving an input analog voltage signal, and dividing the analog voltage signal into a reference voltage; the current bias circuit is coupled to the voltage-current conversion circuit, the current bias circuit compares the analog voltage signal with the working voltage threshold, and provides a bias current to the voltage-current conversion circuit according to the comparison result; the voltage-current conversion circuit is coupled to the output end of the voltage divider circuit, and based on the bias current, converts the reference voltage into a linearly proportional current signal and outputs it through the output port. The technical solution provided by the embodiment of the utility model, through the design of the analog input sampler, can control the entire circuit to work in a linear amplification state according to the input analog signal value, and can replace the optocoupler isolator in situ; and compared with the optocoupler isolator, it can be manufactured using integrated circuit technology, and has the advantage of high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is an overall structural block diagram of the isolator provided in the embodiment of the utility model;

[0042] Figure 2 It is a schematic diagram of the circuit structure of the isolator provided in the embodiment of the utility model;

[0043] Figure 3 Schematic diagram of the circuit structure of the current bias circuit provided by the embodiment of the utility model;

[0044] Figure 4 It is a circuit structure diagram of an LC oscillation circuit provided by another embodiment of the utility model;

[0045] Figure 5 When an analog voltage signal is input, the embodiment of the utility model is Figure 2 The waveform diagram corresponding to the circuit structure diagram shown;

[0046] Figure 6 It is a schematic diagram of the chip packaging structure of the isolator provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is further described in detail below in combination with specific implementation methods and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the utility model. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the utility model.

[0048] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in one or more embodiments of the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in one or more embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0049] The technical solution of the utility model is described in detail below with reference to the accompanying drawings. The embodiment of the utility model provides an isolator, Figure 1 The overall structural block diagram of the isolator provided by the embodiment of the utility model is shown in FIG. Figure 1 As shown, the isolator includes an input side and an output side. The input side includes an isolator input port, an analog input sampler 200, a current transmission circuit 700, an oscillator 300 and a first ground terminal GND1. The output side includes a demodulator 500, an output circuit 600, an isolator output port and a second ground terminal GND2. The input side and the output side isolate and transmit signals through a coupling transmission circuit 400, and the first ground terminal GND1 and the second ground terminal GND2 are isolated from each other.

[0050] The isolator input port is connected to the input port of the analog input sampler 200, and the analog input sampler 200 is configured to receive an input analog voltage signal through the isolator input port, and control the working state of the isolator according to the input analog voltage signal. The analog input sampler 200 includes a voltage divider circuit 203, a current bias circuit 202, and a voltage-to-current conversion circuit 201. The input end of the voltage divider circuit 203 is connected to the input port of the analog input sampler 200 (i.e., the isolator input port), and is used to receive the input analog voltage signal and divide the analog voltage signal into a reference voltage. Figure 2The circuit structure diagram of the isolator provided by the embodiment of the utility model is shown in FIG. Figure 2 As shown, the voltage divider circuit 203 is, for example, composed of two resistors connected in series, and the voltage divider circuit 203 is used to divide the input analog voltage signal to provide a reference voltage for the voltage-current conversion circuit 201 at the back end. According to some optional embodiments, the voltage divider circuit 203 can also be a voltage divider circuit composed of multiple resistors combined to form different circuit structures, such as a voltage divider circuit composed of two resistors connected in parallel and connected in series with other resistors, etc., and the utility model is not limited here. According to some optional embodiments, an anti-reverse injection circuit can also be provided at the connection between the isolator input port and the voltage divider circuit 203, such as the diode D1 provided in this embodiment, the function of the diode D1 is to prevent the forward DC current IF from being reversed, and it is not limited to the anti-reverse injection circuit formed by the diode D1, and other circuits for preventing reverse current from being reversed can also be used, and the utility model is not limited here. The current bias circuit 202 is coupled to the voltage-current conversion circuit 201, and the current bias circuit 202 can provide an operating voltage threshold, and is used to compare the input analog voltage signal with the operating voltage threshold, and provide a bias current to the voltage-current conversion circuit 201 according to the comparison result. Specifically, when the input analog voltage signal is lower than the operating voltage threshold, the entire circuit is in a non-working state; when the input analog voltage signal is higher than the operating voltage threshold, the current bias circuit 202 provides a bias current IB for the voltage-to-current conversion circuit 201, and the voltage-to-current conversion circuit 201 can work normally at this time, which is similar to the characteristics of an optocoupler isolator.

[0051] Figure 3 FIG. 2 shows a schematic diagram of the circuit structure of the current bias circuit 202 provided in an embodiment of the present utility model. Figure 3 As shown, the current bias circuit 202 includes a first transistor MP1, a second transistor MP2, a third transistor MP3, a fourth transistor MN4, a fifth transistor MN5 and a third resistor R3. The third transistor MP3, the second transistor MP2 and the first transistor MP1 are transistors with the same specifications and parameters, and the fifth transistor MN5 and the fourth transistor MN4 are transistors with the same unit size but a ratio of K times. The bias current IB is a current that is independent of the power supply.

[0052] The gates of the first transistor MP1, the second transistor MP2 and the third transistor MP3 are connected to each other and to the drain of the second transistor MP2, and the drain of the third transistor MP3 is used to output the bias current IB to the voltage-current conversion circuit 201. The gates of the fourth transistor MN4 and the fifth transistor MN5 are connected to each other and to the drains of the first transistor MP1 and the fourth transistor MN4, the source of the fourth transistor MN4 is connected to the first ground terminal GND1, the drain of the fifth transistor MN5 is connected to the drain of the second transistor MP2, and the third resistor R3 is connected between the source of the fifth transistor MN5 and the first ground terminal GND1. Among them, the first transistor MP1 and the fourth transistor MN4 are used to provide an operating voltage threshold, and the power supply voltage is higher than the operating voltage threshold provided by the current bias circuit 202, that is, the sum of the threshold voltages of the first transistor MP1 and the fourth transistor MN4. When the power supply voltage is lower than the operating voltage threshold provided by the current bias circuit 202, the overall circuit does not work, and when the power supply voltage is higher than the operating voltage threshold provided by the current bias circuit 202, the overall circuit works normally, so that it can better simulate the characteristics of the optocoupler isolator.

[0053] The voltage-to-current conversion circuit 201 is coupled to the output end of the voltage divider circuit 203 to receive the reference voltage output by the voltage divider circuit 203, and converts the reference voltage into a linearly proportional current signal based on the bias current IB output by the current bias circuit 202. That is, the input analog voltage signal is passed through the voltage divider circuit 203 to generate a reference voltage related to the input analog voltage signal, and the voltage-to-current conversion circuit 201 converts the reference voltage into a linearly proportional current signal. Figure 2 As shown, the voltage-to-current conversion circuit 201 includes an operational amplifier, an output transistor and a first resistor R1. The non-inverting input terminal of the operational amplifier is coupled to the output terminal of the voltage divider circuit 203, the gate of the output transistor is coupled to the output terminal of the operational amplifier, the source of the output transistor is coupled to the inverting input terminal of the operational amplifier, the first resistor R1 is connected between the inverting input terminal of the operational amplifier and the first ground terminal GND1, and the drain of the output transistor forms the output port of the analog input sampler 200.

[0054] like Figure 1 , 2As shown, the input side also includes a current transmission circuit 700 and an oscillator 300. The current transmission circuit 700 is connected between the analog input sampler 200 and the oscillator 300, and the output end of the oscillator 300 is connected to the coupling transmission circuit 400. The current transmission circuit 700 is used to control the current transmission of the oscillator 300 according to the current access direction of the oscillator 300. The current transmission circuit 700 can be implemented by a current mirror circuit, for example. In this embodiment of the utility model, the current transmission circuit 700 includes a sixth transistor MP6, a seventh transistor MP7, an eighth transistor MN8 and a ninth transistor MN9. The sources of the sixth transistor MP6 and the seventh transistor MP7 are connected to each other and connected to the input port of the analog input sampler 200; the gates of the sixth transistor MP6 and the seventh transistor MP7 are connected to each other and connected to the drain of the sixth transistor MP6 and the output port of the analog input sampler 200, that is, the drain of the output transistor. The gates of the eighth transistor MN8 and the ninth transistor MN9 are interconnected, and connected to the drains of the seventh transistor MP7 and the eighth transistor MN8. The sources of the eighth transistor MN8 and the ninth transistor MN9 are interconnected, and connected to the first ground terminal GND1. In this embodiment of the utility model, the oscillator 300 is an LC oscillation circuit, and the input end of the LC oscillation circuit is two signals. When the tail current source is PMOS, the input end of the LC oscillation circuit is respectively connected to the drain end and the ground port of the tail current source; when the tail current source is NMOS, the input end of the LC oscillation circuit is respectively connected to the drain end and the power supply port of the tail current source. The output end of the LC oscillation circuit is connected to the two ends of the primary coil in the coupling transmission circuit 400. The current mirror circuit can also be implemented using a transistor current mirror structure or a CMOS tube current mirror structure, which is not limited by the utility model. The LC oscillation circuit can be implemented using a transistor current mirror structure or a CMOS tube current mirror structure. Figure 2 The complementary cross-coupling structure shown is implemented, which includes a PMOS differential pair of the first oscillation circuit, an NMOS differential pair of the third oscillation circuit, an oscillation capacitor C1, and an oscillation inductor. The PMOS differential pair includes a first oscillation circuit switch M1 and a second oscillation circuit switch M2, and the NMOS differential pair includes a third oscillation circuit switch M3 and a fourth oscillation circuit switch M4, wherein the first oscillation circuit switch M1 and the second oscillation circuit switch M2 are PMOS transistors, and the third oscillation circuit switch M3 and the fourth oscillation circuit switch M4 are NMOS transistors. The oscillation inductor can adopt the primary coil in the coupling transmission circuit 400. Figure 4 FIG. 1 shows a circuit structure diagram of an LC oscillator circuit provided by another embodiment of the present invention, as shown in FIG. Figure 4 As shown, the LC oscillating circuit is realized by two inductors connected to each other, two capacitors connected in series and two oscillating circuit switches cross-coupled.

[0055] The input end of the demodulator 500 is connected to the output end of the coupling transmission circuit 400. The demodulator 500 is used to demodulate the received oscillation signal and generate a signal proportional to the amplitude of the input signal. The demodulator 500 includes a rectifier circuit and a filter circuit connected in series, such as Figure 2 In the embodiment shown, the full-bridge rectifier circuit includes a second diode D2, a third diode D3, a fourth diode D4 and a fifth diode D5, and the filter circuit is a two-stage RC filter circuit, including a second resistor R2, a second capacitor C2 and a third capacitor C3. The output circuit 600 is coupled to the output end of the filter circuit, and the output circuit 600 includes a triode transistor, the base of which is used as an input end and connected to the output end of the filter circuit in the demodulator 500, and the collector of the triode transistor is connected to the isolator output port, and is used to output the transmitted signal through the isolator output port. When an analog voltage signal is input, the second resistor R2 can not only serve as a filter resistor, but also limit the base current value of the triode transistor. The base of the triode transistor is driven by the signal generated by the demodulation circuit, and works in the amplification area. The collector current is the output current, and the collector current is linearly related to the input current. The coupling transmission circuit 400 is used to isolate and transmit the oscillation signal, including a transformer, and can also be implemented by an on-chip transformer, an on-chip capacitor or other methods. The primary side of the transformer is coupled to the oscillator 300, and the secondary side is coupled to the rectifier circuit. When an on-chip transformer is used, the primary coil of the on-chip transformer is connected to the oscillator 300 , and the secondary coil is connected to the demodulator 500 .

[0056] Figure 5 When the analog voltage signal is input, the embodiment of the utility model is Figure 2 The waveform diagram corresponding to the circuit diagram shown in FIG. 1 is a waveform diagram corresponding to the circuit diagram shown in FIG. Among them, the signal at point A is a high-frequency oscillation signal generated by the oscillator 300, the signal at point B is a high-frequency oscillation signal induced by the coupling transmission circuit 400, and the signal at point C is demodulated by the demodulator 500. The output signal is linearly related to the input signal and has an opposite phase. When the input analog voltage signal is lower than the operating voltage threshold of the current bias circuit 202, the entire circuit does not work, and points A, B, and C are all low levels, and the output voltage is high. Figure 5 As shown in the middle area 1; when the input analog voltage signal is higher than the working voltage threshold of the current bias circuit 202, the overall circuit works normally, point A, point B, and point C begin to oscillate, the oscillation amplitude is monotonically related to the input signal, and the output signal is linearly related to the input signal, as shown in FIG. Figure 5 As shown in the middle area 2; when the input analog voltage signal continues to increase or remains at a high voltage, points A, B, and C continue to oscillate, the oscillation amplitude remains unchanged, and the output signal reaches the lowest voltage, as shown in Figure 5 Shown in Central Area 3.

[0057] The isolator provided by the above embodiment of the utility model has four ports, the two ports on the input side are the isolator input port and the first ground terminal, the two ports on the output side are the isolator output port and the second ground terminal, the isolator input port is the input port of the analog input sampler, and the input side and the output side are completely isolated. When an analog signal is input, the triode transistor on the output side works in the amplification region, the collector current is the output current, and the output current is in a quasi-linear relationship with the input current. The isolator can be implemented with an integrated circuit, can transmit analog signals, and the output signal is monotonic with the input signal, thereby overcoming the shortcomings of the optocoupler isolator and realizing in-situ replacement. Figure 6 FIG. 2 shows a schematic diagram of the chip packaging structure of the four-port isolator in the embodiment of the utility model. Figure 6 As shown, the chip packaging structure includes a first bare chip 1, a second bare chip 2, a first pin, a second pin, a third pin and a fourth pin. The analog input sampler 200, the oscillator 300 and the coupling transmission circuit 400 are made on the first bare chip 1; the demodulator 500 and the triode transistor are made on the second bare chip 2. The first bare chip 1 and the second bare chip 2 are packaged in the same tube shell through bonding wires or other connection methods. The isolator input port in the first bare chip 1 is connected to the first pin, and the first ground terminal GND1 is connected to the second pin; the isolator output port in the second bare chip is connected to the third pin, and the second ground terminal GND2 is connected to the fourth pin. In actual operation, the fourth pin can be externally connected to a resistor RL and a power supply to complete the signal output.

[0058] In summary, the utility model provides an analog input sampler and isolator for an isolator and its packaging structure, the analog input sampler includes an input port, a voltage divider circuit, a current bias circuit, a voltage-current conversion circuit and an output port; the input end of the voltage divider circuit is connected to the input port, for receiving an input analog voltage signal, and dividing the analog voltage signal into a reference voltage; the current bias circuit is coupled to the voltage-current conversion circuit, the current bias circuit compares the analog voltage signal with the working voltage threshold, and provides a bias current to the voltage-current conversion circuit according to the comparison result; the voltage-current conversion circuit is coupled to the output end of the voltage divider circuit, and based on the bias current, converts the reference voltage into a linearly proportional current signal and outputs it through the output port. The technical solution provided by the embodiment of the utility model, through the design of the analog input sampler, can control the entire circuit to work in a linear amplification state according to the input analog signal value, and can replace the optocoupler isolator in situ; and compared with the optocoupler isolator, it can be manufactured using integrated circuit technology, and has the advantage of high reliability.

[0059] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation on the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the claims attached to the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the attached claims, or the equivalent forms of such scope and boundaries.

Claims

1. An analog input sampler for an isolator, characterized in that: It includes an input port, a voltage divider circuit, a current bias circuit, a voltage-current conversion circuit and an output port; The input end of the voltage divider circuit is connected to the input port, and is used to receive an input analog voltage signal and divide the analog voltage signal into a reference voltage; The current bias circuit is coupled to the voltage-current conversion circuit, and the current bias circuit compares the analog voltage signal with the operating voltage threshold, and provides a bias current to the voltage-current conversion circuit according to the comparison result; The voltage-to-current conversion circuit is coupled to the output end of the voltage divider circuit, and based on the bias current, converts the reference voltage into a linearly proportional current signal and outputs the signal through the output port.

2. The analog input sampler according to claim 1, characterized in that: The voltage-current conversion circuit includes an operational amplifier and an output transistor; The non-inverting input terminal of the operational amplifier is coupled to the output terminal of the voltage divider circuit; The gate of the output transistor is coupled to the output terminal of the operational amplifier, and the source is coupled to the inverting input terminal of the operational amplifier; The drain of the output transistor is connected to the output port.

3. The analog input sampler according to claim 2, characterized in that: The voltage-current conversion circuit also includes a first resistor; The first resistor is connected between the inverting input terminal of the operational amplifier and a first ground terminal.

4. The analog input sampler according to claim 3, characterized in that: The current bias circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor and a third resistor; The sources of the first transistor, the second transistor and the third transistor are connected to each other and are used to receive the analog voltage signal; The gates of the first transistor, the second transistor and the third transistor are connected to each other and to the drain of the second transistor, and the drain of the third transistor outputs a bias current; The fourth transistor and the first transistor are used to provide an operating voltage threshold; the gates of the fourth transistor and the fifth transistor are connected to each other and to the drains of the first transistor and the fourth transistor, and the source of the fourth transistor is connected to the first ground terminal; The drain of the fifth transistor is connected to the drain of the second transistor; The third resistor is connected between the source of the fifth transistor and the first ground terminal.

5. The analog input sampler according to any one of claims 1 to 4, characterized in that: An anti-backflow circuit is arranged between the input end of the voltage divider circuit and the input port.

6. An isolator, characterized in that: It includes an input side and an output side, wherein the input side and the output side are isolated and transmitted signals through a coupling transmission circuit; The input side includes an isolator input port and an analog input sampler, the isolator input port is connected to the input port of the analog input sampler, the analog input sampler is configured to receive an input analog voltage signal through the isolator input port, and control the working state of the isolator according to the input analog voltage signal; the output side includes an isolator output port for outputting the transmitted signal; The input side includes a first ground terminal, the output side includes a second ground terminal, and the first ground terminal and the second ground terminal are isolated from each other; Wherein, the analog input sampler is the analog input sampler as described in any one of claims 1-5.

7. The isolator according to claim 6, characterized in that The input side also includes a current transmission circuit and an oscillator; The current transmission circuit is connected between the analog input sampler and the oscillator, and the output end of the oscillator is connected to the coupling transmission circuit; The current transmission circuit is used to control the current transmission of the oscillator according to the current access direction of the oscillator.

8. The isolator according to claim 7, characterized in that The current transmission circuit includes a sixth transistor, a seventh transistor, an eighth transistor and a ninth transistor; The sources of the sixth transistor and the seventh transistor are connected to each other and to the input port of the analog input sampler; the gates of the sixth transistor and the seventh transistor are connected to each other and to the drain of the sixth transistor and the output port of the analog input sampler; The gates of the eighth transistor and the ninth transistor are connected to each other and to the drains of the seventh transistor and the eighth transistor, and the sources of the eighth transistor and the ninth transistor are connected to each other and to the first ground terminal.

9. The isolator according to claim 7, characterized in that: The output side also includes a demodulator and an output circuit; The demodulator includes a rectifier circuit and a filter circuit connected in series; The output circuit is coupled to the output end of the filter circuit; The coupling transmission circuit includes a transformer, a primary side of the transformer is coupled to the oscillator, and a secondary side of the transformer is coupled to a rectifier circuit.

10. The isolator according to claim 9, characterized in that The output circuit includes a triode transistor; The base of the triode transistor is connected to the output end of the filter circuit, and the collector of the triode transistor is connected to the isolator output port.

11. A packaging structure of an isolator according to any one of claims 6 to 10, characterized in that: comprising a first bare chip, a second bare chip, a first pin, a second pin, a third pin and a fourth pin; The analog input sampler, oscillator and coupled transmission circuit are arranged on a first bare chip, and the demodulator and output circuit are arranged on a second bare chip; The first bare chip and the second bare chip are packaged in the same tube shell, the isolator input port in the first bare chip is connected to the first pin, and the first ground terminal is connected to the second pin; the isolator output port in the second bare chip is connected to the third pin, and the second ground terminal is connected to the fourth pin.

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