Optocoupler isolation circuit

Abstract

The embodiment of the invention discloses an optocoupler isolation circuit. The optocoupler isolation circuit comprises an optocoupler, a first resistor-capacitor module, a first switch module, a diode module, a second resistor-capacitor module and a second switch module. The first input end of the optocoupler is electrically connected with the first end of the first resistance-capacitance module, and the second end of the first resistance-capacitance module is electrically connected with the first power supply; the first end of the first switch module is electrically connected with the first output end of the optocoupler, and the control end of the first switch module serves as the input end of the optocoupler isolation circuit. The first end of the second resistor-capacitor module is electrically connected with the second input end of the optocoupler, the second end of the second resistor-capacitor module is electrically connected with the control end of the second switch module, the first end of the second switch module is electrically connected with the second power supply, and the second end of the second switch module serves as the output end of the optocoupler isolation circuit. According to the optocoupler isolation circuit provided by the embodiment of the invention, the switching frequency of the optocoupler can be improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to an optocoupler isolation technology, and more particularly to an optocoupler isolation circuit. Background Art

[0002] For devices that need to communicate, such as primary and secondary MCUs, optocouplers such as linear optocouplers are usually used for digital isolation. Currently, the existing optocoupler isolation circuits have the problem of low switching frequency of the optocouplers during operation. Summary of the invention

[0003] An embodiment of the present invention provides an optocoupler isolation circuit to increase the switching frequency of the optocoupler.

[0004] An embodiment of the present invention provides an optocoupler isolation circuit, comprising: an optocoupler, a first resistor and capacitor module, a first switch module, a diode module, a second resistor and capacitor module, and a second switch module;

[0005] The first input end of the optical coupler is electrically connected to the first end of the first resistor and capacitor module, and the second end of the first resistor and capacitor module is electrically connected to the first power supply; the first end of the first switch module is electrically connected to the first output end of the optical coupler, the second end of the first switch module is grounded, and the control end of the first switch module serves as the input end of the optical coupler isolation circuit;

[0006] The input end of the diode module is electrically connected to the second power supply, the output end of the diode module is electrically connected to the second input end of the optocoupler, the second output end of the optocoupler is grounded, the first end of the second resistor and capacitor module is electrically connected to the second input end of the optocoupler, the second end of the second resistor and capacitor module is electrically connected to the control end of the second switch module, the first end of the second switch module is electrically connected to the second power supply, the second end of the second switch module is grounded through a resistor, and the second end of the second switch module serves as the output end of the optocoupler isolation circuit; or, the second input end of the optocoupler is electrically connected to the second power supply, the second output end of the optocoupler is electrically connected to the input end of the diode module, the output end of the diode module is grounded, the first end of the second resistor and capacitor module is electrically connected to the second output end of the optocoupler, the second end of the second resistor and capacitor module is electrically connected to the control end of the second switch module, the first end of the second switch module is electrically connected to the second power supply through a resistor, the first end of the second switch module serves as the output end of the optocoupler isolation circuit, and the second end of the second switch module is grounded.

[0007] Optionally, the first resistor and capacitor module includes a first resistor and a first capacitor, the first end of the first resistor serves as the first end of the first resistor and capacitor module, the second end of the first resistor is electrically connected to the first end of the first capacitor, and the second end of the first capacitor serves as the second end of the first resistor and capacitor module.

[0008] Optionally, the second resistor and capacitor module includes a second resistor and a second capacitor connected in parallel, and the first end and the second end of the second capacitor serve as the first end and the second end of the second resistor and capacitor module.

[0009] Optionally, the first switch module includes a MOS tube; the gate, the first electrode and the second electrode of the MOS tube serve as the control end, the first end and the second end of the first switch module respectively, and the gate and the second electrode of the MOS tube are electrically connected through a resistor.

[0010] Optionally, the second switch module includes a transistor, and a base, a first electrode, and a second electrode of the transistor serve as a control end, a first end, and a second end of the second switch module, respectively.

[0011] Optionally, the diode module includes a first diode and a second diode, the anode of the first diode serves as the input end of the diode module, the cathode of the first diode is electrically connected to the anode of the second diode, and the cathode of the second diode serves as the output end of the diode module.

[0012] Optionally, the above-mentioned optocoupler isolation circuit also includes a third resistor and a fourth resistor, the first input terminal of the optocoupler is electrically connected to the first power supply through the third resistor, the second input terminal of the optocoupler is electrically connected to the second power supply through the fourth resistor, or the second output terminal of the optocoupler is grounded through the fourth resistor.

[0013] Optionally, the resistance of the fourth resistor is smaller than the resistance of the resistor in the second resistor-capacitor module.

[0014] Optionally, the optocoupler includes a light emitting diode and a light receiving transistor, the positive pole and the negative pole of the light emitting diode serve as the first input terminal and the first output terminal of the optocoupler respectively, and the first pole and the second pole of the light receiving transistor serve as the second input terminal and the second output terminal of the optocoupler respectively.

[0015] Optionally, the voltage of the first power supply is different from the voltage of the second power supply.

[0016] The optocoupler isolation circuit provided by the embodiment of the present invention includes: an optocoupler, a first resistor and capacitor module, a first switch module, a diode module, a second resistor and capacitor module, and a second switch module; wherein the first input end of the optocoupler is electrically connected to the first end of the first resistor and capacitor module, and the second end of the first resistor and capacitor module is electrically connected to the first power supply; the first end of the first switch module is electrically connected to the first output end of the optocoupler, the second end of the first switch module is grounded, and the control end of the first switch module serves as the input end of the optocoupler isolation circuit; the input end of the diode module is electrically connected to the second power supply, the output end of the diode module is electrically connected to the second input end of the optocoupler, the second output end of the optocoupler is grounded, the first end of the second resistor and capacitor module is electrically connected to the second input end of the optocoupler, and the second output end of the optocoupler is grounded. The second end of the resistance and capacitance module is electrically connected to the control end of the second switch module, the first end of the second switch module is electrically connected to the second power supply, the second end of the second switch module is grounded through a resistor, and the second end of the second switch module serves as the output end of the optocoupler isolation circuit; or, the second input end of the optocoupler is electrically connected to the second power supply, the second output end of the optocoupler is electrically connected to the input end of the diode module, the output end of the diode module is grounded, the first end of the second resistance and capacitance module is electrically connected to the second output end of the optocoupler, the second end of the second resistance and capacitance module is electrically connected to the control end of the second switch module, the first end of the second switch module is electrically connected to the second power supply through a resistor, the first end of the second switch module serves as the output end of the optocoupler isolation circuit, and the second end of the second switch module is grounded. In the optocoupler isolation circuit provided by the embodiment of the present invention, the diode module is electrically connected to the second input end or the second output end of the optocoupler. When the circuit where the diode module, the second input end and the second output end of the optocoupler are located is turned on, the secondary side of the optocoupler is stabilized by the diode module, and the current of the secondary side of the optocoupler is increased, so that the secondary side of the optocoupler can be quickly turned off; and when the circuit where the second input end and the second output end of the optocoupler are located is disconnected, the capacitor in the second resistor and capacitor module supplies power to the resistor, cuts off the current of the control end of the second switch module, so that the second switch module is disconnected, avoiding the tail of the optocoupler shutdown, and further ensuring that the secondary side of the optocoupler can be quickly turned off; and the current of the primary side of the optocoupler is increased by the first resistor and capacitor module, so that the primary side of the optocoupler can be quickly turned on, thereby realizing the rapid on and off of the optocoupler and improving the switching frequency of the optocoupler. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of an optocoupler isolation circuit provided by an embodiment of the present invention;

[0018] Figure 2 is a structural schematic diagram of another optocoupler isolation circuit provided by an embodiment of the present invention;

[0019] Figure 3 is a schematic diagram of an optocoupler turn-on delay provided by an embodiment of the present invention;

[0020] Figure 4 It is a schematic diagram of an optocoupler turn-off delay provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0022] Figure 1 is a schematic diagram of the structure of an optocoupler isolation circuit provided by an embodiment of the present invention, Figure 2 is a schematic diagram of the structure of another optocoupler isolation circuit provided by an embodiment of the present invention. Figure 1 and Figure 2 The optocoupler isolation circuit includes: an optocoupler 10 , a first resistor and capacitor module 11 , a first switch module 12 , a diode module 20 , a second resistor and capacitor module 21 and a second switch module 22 .

[0023] Among them, the first input end of the optocoupler 10 is electrically connected to the first end of the first resistor and capacitor module 11, and the second end of the first resistor and capacitor module 11 is electrically connected to the first power supply VC1; the first end of the first switch module 12 is electrically connected to the first output end of the optocoupler 10, the second end of the first switch module 12 is grounded, and the control end of the first switch module 12 serves as the input end of the optocoupler isolation circuit; the input end of the diode module 20 is electrically connected to the second power supply VC2, the output end of the diode module 20 is electrically connected to the second input end of the optocoupler 10, the second output end of the optocoupler 10 is grounded, the first end of the second resistor and capacitor module 21 is electrically connected to the second input end of the optocoupler 10, the second end of the second resistor and capacitor module 21 is electrically connected to the control end of the second switch module 22, and the second switch module The first end of the block 22 is electrically connected to the second power supply, the second end of the second switch module 22 is grounded through a resistor, and the second end of the second switch module 22 serves as the output end of the optocoupler isolation circuit; or, the second input end of the optocoupler 10 is electrically connected to the second power supply VC2, the second output end of the optocoupler 10 is electrically connected to the input end of the diode module 20, the output end of the diode module 20 is grounded, the first end of the second resistor and capacitor module 21 is electrically connected to the second output end of the optocoupler 10, the second end of the second resistor and capacitor module 21 is electrically connected to the control end of the second switch module 22, the first end of the second switch module 22 is electrically connected to the second power supply VC2 through a resistor, the first end of the second switch module 22 serves as the output end of the optocoupler isolation circuit, and the second end of the second switch module 22 is grounded.

[0024] Specifically, the optocoupler 10 includes a primary side and a secondary side, the primary side is the first input end and the first output end of the optocoupler 10 where the circuit is located, and the secondary side is the second input end and the second output end of the optocoupler 10 where the circuit is located. Exemplarily, when the input signal IN of the control end of the first switch module 12 is a high-level signal, the first switch module 12 is turned on, the first power supply VC1, the first input end and the first output end of the optocoupler 10, and the circuit where the first switch module 12 is located are turned on (the voltage of the first power supply VC1 is transmitted to the first input end of the optocoupler 10 through the first resistor and capacitor module 11, and the current of the primary side of the optocoupler is increased by the first resistor and capacitor module 11, so that the primary side of the optocoupler can be quickly turned on), at this time, the second power supply VC2, the diode module 20, and the circuit where the second input end and the second output end of the optocoupler 10 are turned on, and the voltage of the second power supply VC2, such as 3.3V, is transmitted to the second input end of the optocoupler 10 through the diode module 20. Since the diode module 20 has a voltage drop such as a 1.2V conduction voltage drop, the voltage of the second input end of the optocoupler 10 is 2.1V. In one connection mode, the input end of the diode module 20 is electrically connected to the second power supply VC2, the output end of the diode module 20 is electrically connected to the second input end of the optocoupler 10, and the first end of the second resistor and capacitor module 21 is electrically connected to the second input end of the optocoupler 10. Figure 1 As shown, the second input end of the optocoupler 10 provides current to the control end of the second switch module 22 through the second resistor and capacitor module 21, the second switch module 22 is turned on, and the voltage of the second power supply VC2 is transmitted from the first end to the second end of the second switch module 22, so the voltage of the output signal OUT at the second end of the second switch module 22 is the voltage of the second power supply VC2. In another connection mode, the second input end of the optocoupler 10 is electrically connected to the second power supply VC2, the second output end of the optocoupler 10 is electrically connected to the input end of the diode module 20, and the first end of the second resistor and capacitor module 21 is electrically connected to the second output end of the optocoupler 10, as shown in FIG. Figure 2As shown, the second output end of the optocoupler 10 provides current to the control end of the second switch module 22 through the second resistor and capacitor module 21, the second switch module 22 is turned on, the second end of the second switch module 22 is grounded, and the second end of the second switch module 22 is equipotential with the first end, so the first end of the second switch module 22 outputs a low level, and at the same time, the second power supply VC2 charges the capacitor C2 in the second resistor and capacitor module 21 through the charging circuit, and the charging circuit is a circuit formed by the second power supply VC2, the second input end and the second output end of the optocoupler 10, the capacitor C2, and the control end and the second end of the second switch module 22. Further, when the control end of the first switch module 12 inputs a level signal such as a low level signal, the first switch module 12 is disconnected, the first power supply VC1, the first input end and the first output end of the optocoupler 10, and the line where the first switch module 12 is located are disconnected, then the second input end and the line where the second output end of the optocoupler 10 are located are disconnected, and the capacitor in the second resistor and capacitor module 21 supplies power to the resistor, cutting off the current of the control end of the second switch module 22, thereby disconnecting the second switch module 22 to avoid the tail of the optocoupler shutdown. In addition, the diode module 20 is electrically connected to the second input terminal or the second output terminal of the optocoupler 10. When the circuits including the second power supply, the diode module 20, the second input terminal and the second output terminal of the optocoupler 10 are turned on, the diode module 20 is used to stabilize the secondary side of the optocoupler to avoid fluctuations in the current transfer ratio of the optocoupler due to ambient temperature, thereby affecting the level of the secondary side of the optocoupler; and the current on the secondary side of the optocoupler is increased, that is, the load / loss on the secondary side of the optocoupler is increased, so that the secondary side of the optocoupler can be quickly shut down.

[0025] In the optocoupler isolation circuit provided in the present embodiment, the diode module is electrically connected to the second input terminal or the second output terminal of the optocoupler. When the circuit where the diode module, the second input terminal and the second output terminal of the optocoupler are located is turned on, the secondary side of the optocoupler is stabilized by the diode module, and the current of the secondary side of the optocoupler is increased, so that the secondary side of the optocoupler can be quickly turned off; and when the circuit where the second input terminal and the second output terminal of the optocoupler are located is disconnected, the capacitor in the second resistor and capacitor module supplies power to the resistor, cuts off the current of the control end of the second switch module, so that the second switch module is disconnected, avoiding the tail of the optocoupler shutdown, and further ensuring that the secondary side of the optocoupler can be quickly turned off; and the current of the primary side of the optocoupler is increased by the first resistor and capacitor module, so that the primary side of the optocoupler can be quickly turned on, thereby realizing the rapid on and off of the optocoupler and improving the switching frequency of the optocoupler.

[0026] refer to Figure 1 and Figure 2 Optionally, the first resistor and capacitor module 11 includes a first resistor R1 and a first capacitor C1, the first end of the first resistor R1 serves as the first end of the first resistor and capacitor module 11, the second end of the first resistor R1 is electrically connected to the first end of the first capacitor C1, and the second end of the first capacitor C1 serves as the second end of the first resistor and capacitor module 11.

[0027] Among them, the first resistor R1 and the first capacitor C1 are connected in series and connected to the first input end of the optocoupler 10. The current of the circuit where the first resistor R1 and the first capacitor C1 are located is transmitted to the first input end of the optocoupler 10 to increase the primary side current when the optocoupler 10 is turned on, to prevent the optocoupler's turn-on delay time from being too high due to the optocoupler's primary side current being too low, thereby reducing the optocoupler's turn-on delay time.

[0028] Continue to refer Figure 1 and Figure 2 Optionally, the second resistor and capacitor module 21 includes a second resistor R2 and a second capacitor C2 connected in parallel, and a first end and a second end of the second capacitor C2 serve as a first end and a second end of the second resistor and capacitor module 21 .

[0029] When the optocoupler 10 is turned on, the second power supply VC2 charges the second capacitor C2 through the line where the second input terminal and the second output terminal of the optocoupler are located. After the second capacitor C2 is fully charged, the second power supply VC2 provides current to the control terminal of the second switch module 22 through the second resistor R2, so that the second switch module 22 is turned on. When the optocoupler 10 is turned off, the second capacitor C2 supplies power to the second resistor R2 and cuts off the current at the control terminal of the second switch module 22, so that the second switch module 22 is quickly turned off to avoid the tail of the optocoupler being turned off.

[0030] Continue to refer Figure 1 and Figure 2 Optionally, the first switch module 12 includes a MOS tube Q1; the gate, the first electrode, and the second electrode of the MOS tube Q1 serve as the control end, the first end, and the second end of the first switch module 12, respectively, and the gate and the second electrode of the MOS tube Q1 are electrically connected through a resistor. Exemplarily, when a high level is input to the gate of the MOS tube Q1 through the resistor, the MOS tube Q1 is turned on, thereby turning on the optical coupler in the circuit where the MOS tube Q1 is located.

[0031] Continue to refer Figure 1 and Figure 2 Optionally, the second switch module 22 includes a transistor Q2, and the base, the first electrode, and the second electrode of the transistor Q2 serve as the control end, the first end, and the second end of the second switch module 22, respectively. Specifically, when the optocoupler 10 is turned on, the transistor Q2 is turned on, and when the optocoupler is turned off, the transistor Q2 is turned off. The on-off of the transistor Q2 ensures that the level of the communication waveform (such as the communication baud rate is 115.2kHz), that is, the signal waveform transmitted by the optocoupler isolation circuit, is not attenuated.

[0032] Continue to refer Figure 1 and Figure 2Optionally, the diode module 20 includes a first diode D1 and a second diode D2, the anode of the first diode D1 serves as the input end of the diode module 20, the cathode of the first diode D1 is electrically connected to the anode of the second diode D2, and the cathode of the second diode D2 serves as the output end of the diode module 20.

[0033] Among them, the first diode D1 and the second diode D2 can be voltage stabilizing diodes, which can stabilize the secondary side of the optocoupler, increase the current, reduce the turn-off delay of the secondary side of the optocoupler, and reduce the conduction voltage drop of the secondary side of the optocoupler to avoid excessive loss of the secondary side of the optocoupler. In addition, the resistance and capacitance of the first resistor and capacitor module 11 increase the primary side current when the optocoupler is turned on, thereby reducing the turn-on delay time of the optocoupler. For example, Figure 3 is a schematic diagram of an optocoupler turn-on delay provided by an embodiment of the present invention, Figure 4 Schematic diagram of an optocoupler turn-off delay provided by an embodiment of the present invention. Figure 3 and Figure 4 , the on-delay time t1 of the optocoupler is 0.664us, and the off-delay time t2 is 0.74us (in the prior art, the on-delay time and off-delay time of the optocoupler are usually more than 3us). The on-delay time t1 and the off-delay time t2 of the above-mentioned optocoupler are only for schematic illustration, which is specifically determined according to the on-off state of the actual optocoupler and is not limited here.

[0034] Continue to refer Figure 1 and Figure 2 Optionally, the above-mentioned optocoupler isolation circuit further includes a third resistor R3 and a fourth resistor R4, the first input end of the optocoupler 10 is electrically connected to the first power supply VC1 through the third resistor R3, the second input end of the optocoupler 10 is electrically connected to the second power supply VC2 through the fourth resistor R4, or the second output end of the optocoupler 10 is grounded through the fourth resistor R4. The resistance value of the third resistor R3 affects the power consumption of the optocoupler in steady state, and the power consumption of the optocoupler in steady state is related to the resistance value of the third resistor R3, and the fourth resistor R4 is a pull-up resistor or a pull-down resistor.

[0035] Optionally, the resistance of the fourth resistor R4 is less than the resistance of the resistor in the second resistor-capacitor module 21. Specifically, if the resistance of the fourth resistor R4 is too large, it will affect the turn-off rate of the second switch module 22 when the current transmission ratio of the optocoupler is insufficient. If the resistance of the fourth resistor R4 is greater than the resistance of the resistor in the second resistor-capacitor module 21, the voltage change amplitude of the end of the optocoupler 10 connected to the fourth resistor R4 is less than the detection amplitude of the second resistor-capacitor module 21 (the second resistor-capacitor module 21 can detect the voltage change of the end of the optocoupler connected to the fourth resistor R4), thereby affecting the turn-off rate of the second switch module 22. Therefore, the resistance of the fourth resistor R4 cannot be greater than the resistance of the resistor in the second resistor-capacitor module 21 to ensure that the second switch module 22 is quickly turned off when the current transmission ratio of the optocoupler is insufficient.

[0036] Optionally, the optical coupler includes a light emitting diode and a light receiving transistor, wherein the positive electrode and the negative electrode of the light emitting diode serve as the first input terminal and the first output terminal of the optical coupler, respectively, and the first electrode and the second electrode of the light receiving transistor serve as the second input terminal and the second output terminal of the optical coupler, respectively. The light emitting diode and the light receiving transistor perform electrical-optical-electrical signal transmission, and the specific working principle can refer to the working principle of the existing optical coupler, which will not be repeated here.

[0037] Optionally, the voltage of the first power source VC1 is different from the voltage of the second power source VC2.

[0038] Exemplarily, the voltage of the first power supply VC1 is 5V, and the voltage of the second power supply VC2 is 3.3V to meet the voltage required for actual power supply. The voltage of the first power supply VC1 and the voltage of the second power supply VC2 are only schematically described here, and can be determined according to actual circuit requirements, and are not limited here.

[0039] The optocoupler isolation circuit provided in this embodiment includes an optocoupler, a first resistor and capacitor module, a first switch module, a diode module, a second resistor and capacitor module, and a second switch module; wherein the first resistor and capacitor module include a first resistor and a first capacitor, the first end of the first resistor serves as the first end of the first resistor and capacitor module, the second end of the first resistor is electrically connected to the first end of the first capacitor, and the second end of the first capacitor serves as the second end of the first resistor and capacitor module; the second resistor and capacitor module includes a second resistor and a second capacitor connected in parallel, the first end and the second end of the second capacitor serve as the first end and the second end of the second resistor and capacitor module; the second switch module includes a triode, the base, the first pole and the second pole of the triode serve as the control end, the first end and the second end of the second switch module respectively; the input end of the diode module is electrically connected to the second power supply, the output end of the diode module is electrically connected to the second input end of the optocoupler, and the second output end of the optocoupler is grounded, or the second input end of the optocoupler is electrically connected to the second power supply, the second output end of the optocoupler is electrically connected to the input end of the diode module, and the output end of the diode module is grounded. In the optocoupler isolation circuit provided in this embodiment, when the circuit where the diode module, the second input terminal and the second output terminal of the optocoupler are located is turned on, the diode module is used to stabilize the secondary side of the optocoupler to avoid the current transmission ratio fluctuation of the optocoupler caused by the ambient temperature, which affects the level of the secondary side of the optocoupler; the secondary side current of the optocoupler is increased to reduce the shutdown delay of the secondary side of the optocoupler; the conduction voltage drop of the secondary side of the optocoupler is reduced to avoid excessive loss of the secondary side of the optocoupler and reduce the loss of the optocoupler; when the circuit where the second input terminal and the second output terminal of the optocoupler are located is disconnected, the second capacitor supplies power to the second resistor to cut off the base current of the transistor, thereby disconnecting the transistor and avoiding the tailing of the optocoupler shutdown. In addition, the current of the circuit where the first resistor and the first capacitor are located is transmitted to the first input terminal of the optocoupler to increase the primary side current of the optocoupler to prevent the turn-on delay time of the optocoupler from being high due to the low primary side current of the optocoupler, thereby reducing the turn-on delay time of the optocoupler.

[0040] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An optocoupler isolation circuit, characterized in that: include: Optocoupler, first resistor and capacitor module, first switch module, diode module, second resistor and capacitor module and second switch module; The first input end of the optical coupler is electrically connected to the first end of the first resistor and capacitor module, and the second end of the first resistor and capacitor module is electrically connected to the first power supply; the first end of the first switch module is electrically connected to the first output end of the optical coupler, the second end of the first switch module is grounded, and the control end of the first switch module serves as the input end of the optical coupler isolation circuit; The input end of the diode module is electrically connected to the second power supply, the output end of the diode module is electrically connected to the second input end of the optocoupler, the second output end of the optocoupler is grounded, the first end of the second resistor and capacitor module is electrically connected to the second input end of the optocoupler, the second end of the second resistor and capacitor module is electrically connected to the control end of the second switch module, the first end of the second switch module is electrically connected to the second power supply, the second end of the second switch module is grounded through a resistor, and the second end of the second switch module serves as the output end of the optocoupler isolation circuit; or, the second input end of the optocoupler is electrically connected to the second power supply, the second output end of the optocoupler is electrically connected to the input end of the diode module, the output end of the diode module is grounded, the first end of the second resistor and capacitor module is electrically connected to the second output end of the optocoupler, the second end of the second resistor and capacitor module is electrically connected to the control end of the second switch module, the first end of the second switch module is electrically connected to the second power supply through a resistor, the first end of the second switch module serves as the output end of the optocoupler isolation circuit, and the second end of the second switch module is grounded.

2. The optocoupler isolation circuit according to claim 1, characterized in that: The first resistor and capacitor module includes a first resistor and a first capacitor, the first end of the first resistor serves as the first end of the first resistor and capacitor module, the second end of the first resistor is electrically connected to the first end of the first capacitor, and the second end of the first capacitor serves as the second end of the first resistor and capacitor module.

3. The optocoupler isolation circuit according to claim 1, characterized in that: The second resistor and capacitor module includes a second resistor and a second capacitor connected in parallel, and a first end and a second end of the second capacitor serve as a first end and a second end of the second resistor and capacitor module.

4. The optocoupler isolation circuit according to claim 1, characterized in that: The first switch module includes a MOS tube; the gate, the first electrode and the second electrode of the MOS tube serve as the control end, the first end and the second end of the first switch module respectively, and the gate and the second electrode of the MOS tube are electrically connected through a resistor.

5. The optocoupler isolation circuit according to claim 1, characterized in that: The second switch module includes a transistor, and a base, a first electrode, and a second electrode of the transistor serve as a control terminal, a first terminal, and a second terminal of the second switch module respectively.

6. The optocoupler isolation circuit according to claim 1, characterized in that: The diode module includes a first diode and a second diode, the anode of the first diode serves as the input end of the diode module, the cathode of the first diode is electrically connected to the anode of the second diode, and the cathode of the second diode serves as the output end of the diode module.

7. The optocoupler isolation circuit according to claim 1, characterized in that: It also includes a third resistor and a fourth resistor, the first input end of the optocoupler is electrically connected to the first power supply through the third resistor, the second input end of the optocoupler is electrically connected to the second power supply through the fourth resistor, or the second output end of the optocoupler is grounded through the fourth resistor.

8. The optocoupler isolation circuit according to claim 7, characterized in that: The resistance value of the fourth resistor is smaller than the resistance value of the resistor in the second resistor-capacitor module.

9. The optocoupler isolation circuit according to claim 1, characterized in that: The optical coupler includes a light emitting diode and a light receiving transistor, wherein the positive electrode and the negative electrode of the light emitting diode serve as the first input terminal and the first output terminal of the optical coupler respectively, and the first electrode and the second electrode of the light receiving transistor serve as the second input terminal and the second output terminal of the optical coupler respectively.

10. The optocoupler isolation circuit according to claim 1, characterized in that: The voltage of the first power supply is different from the voltage of the second power supply.

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