An isolated feedback circuit for detecting the output state of an optocoupler

Abstract

The present invention discloses an isolation feedback circuit for detecting the output state of an optocoupler, which is applied to an optocoupler module connected to a load. The circuit includes a main control module, an isolation feedback module, a current detection module, a current upper limit comparison module, a current lower limit comparison module, a voltage detection module, and a voltage comparison module; the optocoupler module is also connected to the main control module and the current detection module respectively; the current detection module is connected to the current upper limit comparison module and the current lower limit comparison module respectively; the voltage detection module is connected in parallel with the load, and the voltage detection module is connected to the voltage comparison module; the current upper limit comparison module, the current lower limit comparison module, and the voltage comparison module are all connected to the isolation feedback module; the isolation feedback module is connected to the main control module. The present invention can clearly know the output state of the output end of the optocoupler module in real time, so as to timely learn about the abnormality of the output end of the optocoupler module, thereby reducing the impact on the normal output of the signal and avoiding safety problems.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor integrated circuits, and particularly to an isolation feedback circuit for detecting the output state of an optocoupler. Background Art

[0002] An optical coupler (Optical Coupler Equipment, abbreviated as OCEP), also known as an opto-isolator or an opto-coupler, is simply called an optocoupler. An optocoupler is a device that transmits electrical signals through light. Since it has good isolation for input and output electrical signals, it has been widely used in various circuits.

[0003] Currently, the isolation function of the optocoupler makes it impossible for the input end of the optocoupler to directly know the output state of the output end of the optocoupler. For example, when a control signal is input to the input end of the optocoupler, the input end of the optocoupler cannot know whether the output end of the optocoupler has performed corresponding actions according to the control signal. In this way, it is possible that a fault anomaly occurs at the output end of the optocoupler and it is impossible to know, which will not only affect the normal output of the signal, but is also very likely to cause safety problems.

[0004] Therefore, it is necessary to improve the existing technology.

[0005] The above information is given as background information only to assist in understanding the present disclosure, and does not determine or admit whether any of the above content can be used as the prior art relative to the present disclosure. Summary of the Invention

[0006] The present invention provides an isolation feedback circuit for detecting the output state of an optocoupler to solve the deficiencies of the existing technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] An isolation feedback circuit for detecting the output state of an optocoupler, which is applied to an optocoupler module. The first input end of the optocoupler module is connected to a load, and the circuit includes a main control module, an output detection module, and an isolation feedback module; wherein,

[0009] The output detection module includes a current detection module, a current upper limit comparison module, a current lower limit comparison module, a voltage detection module, and a voltage comparison module;

[0010] The second input end of the optocoupler module is connected to the output end of the main control module, and the output end of the optocoupler module is connected to the input end of the current detection module;

[0011] The output end of the current detection module is respectively connected to the input end of the current upper limit comparison module and the input end of the current lower limit comparison module;

[0012] The input end of the voltage detection module is connected in parallel with the load, and the output end of the voltage detection module is connected to the input end of the voltage comparison module;

[0013] The output end of the current upper limit comparison module is connected to the first input end of the isolation feedback module, the output end of the current lower limit comparison module is connected to the second input end of the isolation feedback module, and the output end of the voltage comparison module is connected to the third input end of the isolation feedback module;

[0014] The output end of the isolation feedback module is connected to the input end of the main control module;

[0015] The current detection module is used to detect the load current at the output end of the optocoupler module and supply the load current to the current upper limit comparison module and the current lower limit comparison module;

[0016] The current upper limit comparison module is used to compare the load current with a set current upper limit to determine whether the load current exceeds the current upper limit, so as to obtain a current upper limit comparison result;

[0017] The current lower limit comparison module is used to compare the load current with a set current lower limit to determine whether the load current reaches the current lower limit, so as to obtain a current lower limit comparison result;

[0018] The voltage detection module is used to detect the load voltage at the output end of the optocoupler module and supply the load voltage to the voltage comparison module;

[0019] The voltage comparison module is used to compare the load voltage with a set short - circuit voltage to determine whether the load voltage reaches the short - circuit voltage, so as to obtain a voltage comparison result;

[0020] The main control module is used to output a conduction signal to turn on the optocoupler module, and read the current upper limit comparison result, current lower limit comparison result, and voltage comparison result input by the isolation feedback module, so as to know whether the output end of the optocoupler module is conducting; and, it is used to output a cut - off signal to turn off the optocoupler module, and read the current upper limit comparison result, current lower limit comparison result, and voltage comparison result input by the isolation feedback module, so as to know whether the output end of the optocoupler module is cut off.

[0021] Further, in the isolation feedback circuit for detecting the output state of the optocoupler, the current detection module includes a first operational amplifier U3, a first resistor R1, and a third resistor R3;

[0022] The positive input terminal of the first operational amplifier U3 is connected to the optocoupler module. The negative input terminal of the first operational amplifier U3 is grounded through the first resistor R1. The output terminal of the first operational amplifier U3 is connected to the current upper limit comparison module;

[0023] One end of the third resistor R3 is connected to the output terminal of the first operational amplifier U3, and the other end of the third resistor R3 is connected between the negative input terminal of the first operational amplifier U3 and the first resistor R1.

[0024] Further, in the isolation feedback circuit for detecting the output state of the optocoupler, the current upper limit comparison module includes a first voltage comparator U5, a fourteenth resistor R14, a fifteenth resistor R15, and a first voltage reference source VREF1;

[0025] One end of the fourteenth resistor R14 is connected to the power supply terminal of the first voltage comparator U5, and the other end of the fourteenth resistor R14 is connected to one end of the fifteenth resistor R15; the other end of the fifteenth resistor R15 is grounded;

[0026] The positive input terminal of the first voltage comparator U5 is connected to the first voltage reference source VREF1 and then connected between the fourteenth resistor R14 and the fifteenth resistor R15;

[0027] The negative input terminal of the first voltage comparator U5 is connected to the output terminal of the first operational amplifier U3;

[0028] The output terminal of the first voltage comparator U5 is connected to the first input terminal of the isolation feedback module.

[0029] Further, in the isolation feedback circuit for detecting the output state of the optocoupler, the current lower limit comparison module includes a second voltage comparator U6, a sixteenth resistor R16, a seventeenth resistor R17, and a second voltage reference source VREF2;

[0030] One end of the sixteenth resistor R16 is connected to the power supply terminal of the second voltage comparator U6, and the other end of the sixteenth resistor R16 is connected to one end of the seventeenth resistor R17; the other end of the seventeenth resistor R17 is grounded;

[0031] The positive input terminal of the second voltage comparator U6 is connected to the second voltage reference source VREF2 and then connected between the sixteenth resistor R16 and the seventeenth resistor R17;

[0032] The negative input terminal of the second voltage comparator U6 is connected to the output terminal of the first operational amplifier U3;

[0033] The output terminal of the second voltage comparator U6 is connected to the second input terminal of the isolation feedback module.

[0034] Further, in the isolation feedback circuit for detecting the output state of the optocoupler, the voltage detection module includes a second operational amplifier U4, a twenty-sixth resistor R26, a twenty-seventh resistor R27, a twenty-eighth resistor R28, and a twenty-ninth resistor R29;

[0035] The positive input terminal of the second operational amplifier U4 is connected to the first end of the load through the twenty-seventh resistor R27, the negative input terminal of the second operational amplifier U4 is connected to the second end of the load through the twenty-sixth resistor R26, and the output terminal of the second operational amplifier U4 is connected to the input terminal of the voltage comparison module;

[0036] One end of the twenty-eighth resistor R28 is connected between the second operational amplifier U4 and the twenty-sixth resistor R26, and the other end of the twenty-eighth resistor R28 is connected to the output terminal of the second operational amplifier U4;

[0037] One end of the twenty-ninth resistor R29 is connected between the second operational amplifier U4 and the twenty-seventh resistor R27, and the other end of the twenty-ninth resistor R29 is grounded.

[0038] Further, in the isolation feedback circuit for detecting the output state of the optocoupler, the voltage comparison module includes a third voltage comparator U7, a twentieth resistor R20, a twenty-first resistor R21, and a third voltage reference source VREF3;

[0039] One end of the twentieth resistor R20 is connected to the power supply terminal of the third voltage comparator U7, and the other end of the twentieth resistor R20 is connected to one end of the twenty-first resistor R21; the other end of the twenty-first resistor R21 is grounded;

[0040] The positive input terminal of the third voltage comparator U7 is connected to the third voltage reference source VREF3 and then connected between the twentieth resistor R20 and the twenty-first resistor R21;

[0041] The negative input terminal of the third voltage comparator U7 is connected to the output terminal of the second operational amplifier U4;

[0042] The output terminal of the third voltage comparator U7 is connected to the third input terminal of the isolation feedback module.

[0043] Further, in the isolation feedback circuit for detecting the output state of the optocoupler, the isolation feedback module includes a first optocoupler U8, a second optocoupler U9, a third optocoupler U10, an isolation chip U11, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a twenty-fourth resistor R24, and a twenty-fifth resistor R25;

[0044] One end of the first pin of the first optocoupler U8 is connected to one end of the fifth resistor R5, the second pin of the first optocoupler U8 is connected to the output end of the first voltage comparator U5, the third pin of the first optocoupler U8 is grounded, and the fourth pin of the first optocoupler U8 is respectively connected to one end of the seventh resistor R7 and the input end of the main control module;

[0045] One end of the first pin of the second optocoupler U9 is connected to one end of the sixth resistor R6, the second pin of the second optocoupler U9 is connected to the output end of the first voltage comparator U5, the third pin of the second optocoupler U9 is grounded, and the fourth pin of the second optocoupler U9 is respectively connected to one end of the eighth resistor R8 and the input end of the main control module;

[0046] One end of the first pin of the third optocoupler U10 is connected to one end of the twenty-fourth resistor R24, the second pin of the third optocoupler U10 is connected to the output end of the first voltage comparator U5, the third pin of the third optocoupler U10 is grounded, and the fourth pin of the third optocoupler U10 is respectively connected to one end of the twenty-fifth resistor R25 and the input end of the main control module.

[0047] Further, in the isolation feedback circuit for detecting the output state of the optocoupler, the main control module includes a main control chip U1, a ninth resistor R9, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a first capacitor C1, a second capacitor C2, a third capacitor C3, and a crystal oscillator Y1;

[0048] The PA0 pin of the main control chip U1 is connected to the first input end of the optocoupler module, the PA1 pin of the main control chip U1 is connected to the fourth pin of the first optocoupler U8, the PA2 pin of the main control chip U1 is connected to the fourth pin of the second optocoupler U9, and the PA3 pin of the main control chip U1 is connected to the fourth pin of the third optocoupler U10;

[0049] One end of the eleventh resistor R11 is connected to the BOOT2 pin of the main control chip U1, and the other end of the eleventh resistor R11 is grounded;

[0050] One end of the twelfth resistor R12 is connected to the BOOT1 pin of the main control chip U1, and the other end of the twelfth resistor R12 is grounded;

[0051] One end of the third capacitor C3 is connected to the OSC_0 pin of the main control chip U1, and the other end of the third capacitor C3 is grounded;

[0052] One end of the second capacitor C2 is connected to the OCS_1 pin of the main control chip U1, and the other end of the second capacitor C2 is grounded;

[0053] One end of the thirteenth resistor R13 is connected between the OSC_0 pin of the main control chip U1 and the third capacitor C3, and the other end of the thirteenth resistor R13 is connected between the OCS_1 pin of the main control chip U1 and the second capacitor C2;

[0054] One end of the crystal oscillator Y1 is connected between the OSC_0 pin of the main control chip U1 and the third capacitor C3, and the other end of the crystal oscillator Y1 is connected between the OCS_1 pin of the main control chip U1 and the second capacitor C2.

[0055] Further, in the isolation feedback circuit for detecting the output state of the optocoupler, the optocoupler module includes a fourth optocoupler U2, an NMOS transistor Q1, an eighteenth resistor R18, a nineteenth resistor R19, a parameter resistor Rout, and a second diode D2;

[0056] The first pin of the fourth optocoupler U2 is connected to the PA0 pin of the main control chip U1 through the eighteenth resistor R18, the second pin of the fourth optocoupler U2 is grounded, and the third pin of the fourth optocoupler U2 is connected to the gate of the NMOS transistor Q1;

[0057] One end of the nineteenth resistor R19 is connected between the third pin of the fourth optocoupler U2 and the gate of the NMOS transistor Q1, and the other end of the nineteenth resistor R19 is grounded;

[0058] One end of the parameter resistor Rout is connected to the source of the NMOS transistor Q1, and the other end of the parameter resistor Rout is grounded;

[0059] The drain of the NMOS transistor Q1 is connected to the second end of the load;

[0060] The positive electrode of the second diode D2 is respectively connected to the source of the NMOS transistor Q1 and the positive input terminal of the first operational amplifier U3, and the negative electrode of the second diode D2 is connected to the drain of the NMOS transistor Q1.

[0061] Further, in the isolation feedback circuit for detecting the output state of the optocoupler, the load includes a relay and a first diode D1;

[0062] One end of the relay is respectively connected to the source of the NMOS transistor Q1, the twenty-sixth resistor R26, and the positive electrode of the first diode D1, and the other end of the relay is respectively connected to the twenty-seventh resistor R27 and the negative electrode of the first diode D1.

[0063] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0064] An isolation feedback circuit for detecting the output state of an optocoupler provided by an embodiment of the present invention forms an isolation feedback circuit through a main control module, an output detection module, and an isolation feedback module, and quickly feeds back the output state of the output end of the optocoupler module to the main control module with simple level information, so that the main control module can clearly know the output state of the output end of the optocoupler module in real time, so as to timely learn about the abnormality of the output end of the optocoupler module, thereby reducing the impact on the normal output of the signal and avoiding causing safety problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0066] Figure 1 It is a schematic diagram of a circuit module of an isolation feedback circuit for detecting the output state of an optocoupler provided by an embodiment of the present invention;

[0067] Figure 2 It is a schematic diagram of the circuit principle of an isolation feedback circuit for detecting the output state of an optocoupler provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0068] In order to make the objectives, features, and advantages of the present invention more obvious and understandable, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the following described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0069] In the description of the present invention, it should be understood that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component.

[0070] In addition, terms such as "long", "short", "inner", "outer", etc. indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or component referred to must have this specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention.

[0071] The technical solution of the present invention will be further described below in conjunction with the drawings and specific embodiments.

[0072] Embodiment 1

[0073] In view of the above-mentioned defect that the output state of the optocoupler output terminal cannot be known in the existing technology, based on the rich practical experience and professional knowledge in the design and manufacture of this field for many years by the applicant, and in cooperation with the application of theory, active research and innovation have been carried out in the hope of creating a technology that can solve the defects in the existing technology, so that the output state of the optocoupler output terminal can be known. After continuous research, design, and repeated sample making and improvement, the present invention with practical value has finally been created.

[0074] Please refer to Figure 1-2 , an isolation feedback circuit for detecting the output state of an optocoupler is provided in an embodiment of the present invention, which is applied to an optocoupler module. The first input terminal of the optocoupler module is connected to a load. The circuit includes a main control module, an output detection module, and an isolation feedback module; wherein,

[0075] The output detection module includes a current detection module, a current upper limit comparison module, a current lower limit comparison module, a voltage detection module, and a voltage comparison module;

[0076] The second input terminal of the optocoupler module is connected to the output terminal of the main control module, and the output terminal of the optocoupler module is connected to the input terminal of the current detection module;

[0077] The output terminal of the current detection module is respectively connected to the input terminal of the current upper limit comparison module and the input terminal of the current lower limit comparison module;

[0078] The input terminal of the voltage detection module is connected in parallel with the load, and the output terminal of the voltage detection module is connected to the input terminal of the voltage comparison module;

[0079] The output terminal of the current upper limit comparison module is connected to the first input terminal of the isolation feedback module, the output terminal of the current lower limit comparison module is connected to the second input terminal of the isolation feedback module, and the output terminal of the voltage comparison module is connected to the third input terminal of the isolation feedback module;

[0080] The output terminal of the isolation feedback module is connected to the input terminal of the main control module;

[0081] The current detection module is used to detect the load current at the output end of the optocoupler module and supply the load current to the current upper limit comparison module and the current lower limit comparison module;

[0082] The current upper limit comparison module is used to compare the load current with a set current upper limit to determine whether the load current exceeds the current upper limit, that is, whether there is overcurrent, so as to obtain a current upper limit comparison result;

[0083] The current lower limit comparison module is used to compare the load current with a set current lower limit for normal operation of the load to determine whether the load current reaches the current lower limit, that is, whether there is an open circuit, so as to obtain a current lower limit comparison result;

[0084] The voltage detection module is used to detect the load voltage at the output end of the optocoupler module and supply the load voltage to the voltage comparison module;

[0085] The voltage comparison module is used to compare the load voltage with a set short - circuit voltage to determine whether the load voltage reaches the short - circuit voltage, so as to obtain a voltage comparison result;

[0086] The main control module is used to output a conduction signal to turn on the optocoupler module, and read the current upper limit comparison result, the current lower limit comparison result, and the voltage comparison result input by the isolation feedback module, and determine whether the output end of the optocoupler module is cutoff, short - circuited, over - current, or normally conducting, so as to know whether the output end of the optocoupler module is conducting; and, it is used to output a cutoff signal to turn off the optocoupler module, and read the current upper limit comparison result, the current lower limit comparison result, and the voltage comparison result input by the isolation feedback module, and determine whether the output end of the optocoupler module is cutoff, short - circuited, over - current, or normally conducting, so as to know whether the output end of the optocoupler module is cutoff.

[0087] It should be noted that the set current upper limit, the set current lower limit, and the set short - circuit voltage are all set by technicians based on experience. This experience is obtained based on specific experimental results and can be any value.

[0088] In this embodiment, the current detection module includes a first operational amplifier U3, a first resistor R1, and a third resistor R3;

[0089] The positive input end of the first operational amplifier U3 is connected to the optocoupler module, the negative input end of the first operational amplifier U3 is grounded (GND2) through the first resistor R1, and the output end of the first operational amplifier U3 is connected to the current upper limit comparison module;

[0090] One end of the third resistor R3 is connected to the output terminal of the first operational amplifier U3, and the other end of the third resistor R3 is connected between the negative input terminal of the first operational amplifier U3 and the first resistor R1.

[0091] The power supply terminal of the first operational amplifier U3 is connected to the voltage EXT_5V, and the ground terminal of the first operational amplifier U3 is grounded (GND2);

[0092] It should be noted that the first operational amplifier U3 can select an operational amplifier with the product model LM258, and the amplification factor is The resistance value of the first resistor R1 can be selected as 5 kΩ, and the resistance value of the third resistor R3 can be selected as 5 kΩ.

[0093] In this embodiment, the current upper limit comparison module includes a first voltage comparator U5, a fourteenth resistor R14, a fifteenth resistor R15, and a first voltage reference source VREF1;

[0094] One end of the fourteenth resistor R14 is connected to the power supply terminal of the first voltage comparator U5, and the other end of the fourteenth resistor R14 is connected to one end of the fifteenth resistor R15; the other end of the fifteenth resistor R15 is grounded (GND2);

[0095] The positive input terminal of the first voltage comparator U5 is connected to the first voltage reference source VREF1 and then connected between the fourteenth resistor R14 and the fifteenth resistor R15;

[0096] The negative input terminal of the first voltage comparator U5 is connected to the output terminal of the first operational amplifier U3;

[0097] The output terminal of the first voltage comparator U5 is connected to the first input terminal of the isolation feedback module.

[0098] The power supply terminal of the first voltage comparator U5 is connected to the voltage EXT_5V, and the ground terminal of the first voltage comparator U5 is grounded (GND2);

[0099] It should be noted that the first voltage comparator U5 can select a voltage comparator with the product model LM339, the resistance value of the fourteenth resistor R14 can be selected as 3 kΩ, and the resistance value of the fifteenth resistor R15 can be selected as 2 kΩ.

[0100] In this embodiment, the current lower limit comparison module includes a second voltage comparator U6, a sixteenth resistor R16, a seventeenth resistor R17, and a second voltage reference source VREF2;

[0101] One end of the sixteenth resistor R16 is connected to the power supply terminal of the second voltage comparator U6, and the other end of the sixteenth resistor R16 is connected to one end of the seventeenth resistor R17; the other end of the seventeenth resistor R17 is grounded (GND2);

[0102] The positive input terminal of the second voltage comparator U6 is connected to the second voltage reference source VREF2 and then connected between the sixteenth resistor R16 and the seventeenth resistor R17;

[0103] The negative input terminal of the second voltage comparator U6 is connected to the output terminal of the first operational amplifier U3;

[0104] The output terminal of the second voltage comparator U6 is connected to the second input terminal of the isolation feedback module.

[0105] The power supply terminal of the second voltage comparator U6 is connected to the voltage EXT_5V, and the ground terminal of the second voltage comparator U6 is grounded (GND2);

[0106] It should be noted that the second voltage comparator U6 can select a voltage comparator with the product model LM339, the resistance value of the sixteenth resistor R16 can be selected as 4.8 kΩ, and the resistance value of the seventeenth resistor R17 can be selected as 200 Ω.

[0107] In this embodiment, the voltage detection module includes a second operational amplifier U4, a twenty-sixth resistor R26, a twenty-seventh resistor R27, a twenty-eighth resistor R28, and a twenty-ninth resistor R29;

[0108] The positive input terminal of the second operational amplifier U4 is connected to the first end of the load through the twenty-seventh resistor R27, the negative input terminal of the second operational amplifier U4 is connected to the second end of the load through the twenty-sixth resistor R26, and the output terminal of the second operational amplifier U4 is connected to the input terminal of the voltage comparison module;

[0109] One end of the twenty-eighth resistor R28 is connected between the second operational amplifier U4 and the twenty-sixth resistor R26, and the other end of the twenty-eighth resistor R28 is connected to the output terminal of the second operational amplifier U4;

[0110] One end of the twenty-ninth resistor R29 is connected between the second operational amplifier U4 and the twenty-seventh resistor R27, and the other end of the twenty-ninth resistor R29 is grounded (GND2).

[0111] The power supply terminal of the second operational amplifier U4 is connected to the voltage EXT_5V, and the ground terminal of the second operational amplifier U4 is grounded (GND2);

[0112] It should be noted that the second operational amplifier U4 can select an operational amplifier with the product model LM258, and the amplification factor is The resistance value of the twenty-sixth resistor R26 can be selected as 10 KΩ, the resistance value of the twenty-seventh resistor R27 can be selected as 10 KΩ, the resistance value of the twenty-eighth resistor R28 can be selected as 1 KΩ, and the resistance value of the twenty-ninth resistor R29 can be selected as 1 KΩ.

[0113] In this embodiment, the voltage comparison module includes a third voltage comparator U7, a twentieth resistor R20, a twenty-first resistor R21, and a third voltage reference source VREF3;

[0114] One end of the twentieth resistor R20 is connected to the power supply terminal of the third voltage comparator U7, and the other end of the twentieth resistor R20 is connected to one end of the twenty-first resistor R21; the other end of the twenty-first resistor R21 is grounded (GND2);

[0115] The positive input terminal of the third voltage comparator U7 is connected to the third voltage reference source VREF3 and then connected between the twentieth resistor R20 and the twenty-first resistor R21;

[0116] The negative input terminal of the third voltage comparator U7 is connected to the output terminal of the second operational amplifier U4;

[0117] The output terminal of the third voltage comparator U7 is connected to the third input terminal of the isolation feedback module.

[0118] The power supply terminal of the third voltage comparator U7 is connected to the voltage EXT_5V, and the ground terminal of the third voltage comparator U7 is grounded (GND2);

[0119] It should be noted that the third voltage comparator U7 can select a voltage comparator with the product model LM339, the resistance value of the twentieth resistor R20 can be selected as 4.8 KΩ, and the resistance value of the twenty-first resistor R21 can be selected as 200 KΩ.

[0120] In this embodiment, the isolation feedback module includes a first optocoupler U8, a second optocoupler U9, a third optocoupler U10, an isolation chip U11, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a twenty-fourth resistor R24, and a twenty-fifth resistor R25;

[0121] The first pin of the first optocoupler U8 is connected to one end of the fifth resistor R5. The second pin of the first optocoupler U8 is connected to the output end of the first voltage comparator U5. The third pin of the first optocoupler U8 is grounded (GND1). The fourth pin of the first optocoupler U8 is respectively connected to one end of the seventh resistor R7 and the input end of the main control module;

[0122] The first pin of the second optocoupler U9 is connected to one end of the sixth resistor R6. The second pin of the second optocoupler U9 is connected to the output end of the first voltage comparator U5. The third pin of the second optocoupler U9 is grounded (GND1). The fourth pin of the second optocoupler U9 is respectively connected to one end of the eighth resistor R8 and the input end of the main control module;

[0123] The first pin of the third optocoupler U10 is connected to one end of the twenty-fourth resistor R24. The second pin of the third optocoupler U10 is connected to the output end of the first voltage comparator U5. The third pin of the third optocoupler U10 is grounded (GND1). The fourth pin of the third optocoupler U10 is respectively connected to one end of the twenty-fifth resistor R25 and the input end of the main control module.

[0124] The other ends of the seventh resistor R7, the eighth resistor R8 and the twenty-fifth resistor R25 are respectively connected to the voltage +3.3V. The other ends of the fifth resistor R5, the sixth resistor R6 and the twenty-fourth resistor R24 are respectively connected to EXT_5V;

[0125] The VIN pin of the isolation chip U11 is connected to the voltage +5V. The GND pin of the isolation chip U11 is grounded (GND1). The +Vo pin of the isolation chip U11 is connected to the voltage EXT_5V. The Vo pin of the isolation chip U11 is grounded (GND2);

[0126] It should be noted that the first optocoupler U8, the second optocoupler U9 and the third optocoupler U10 can all select optocouplers of model TLP291. The isolation chip U11 can select a chip of model IF0505S. The resistance value of the fifth resistor R5 can be selected as 1kΩ. The resistance value of the sixth resistor R6 can be selected as 1kΩ. The resistance value of the seventh resistor R7 can be selected as 1kΩ. The resistance value of the eighth resistor R8 can be selected as 1kΩ. The resistance value of the twenty-fourth resistor R24 can be selected as 1kΩ. The resistance value of the twenty-fifth resistor R25 can be selected as 1kΩ.

[0127] The isolation feedback module isolates the voltage 5V and GND1 of the main control module from the voltage EXT_5V and GND2 of the output detection module and the optocoupler module.

[0128] In this embodiment, the main control module includes a main control chip U1, a ninth resistor R9, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a first capacitor C1, a second capacitor C2, a third capacitor C3, and a crystal oscillator Y1;

[0129] The PA0 pin of the main control chip U1 is connected to the first input end of the optocoupler module. The PA1 pin of the main control chip U1 is connected to the fourth pin of the first optocoupler U8. The PA2 pin of the main control chip U1 is connected to the fourth pin of the second optocoupler U9. The PA3 pin of the main control chip U1 is connected to the fourth pin of the third optocoupler U10;

[0130] One end of the eleventh resistor R11 is connected to the BOOT2 pin of the main control chip U1, and the other end of the eleventh resistor R11 is grounded (GND1);

[0131] One end of the twelfth resistor R12 is connected to the BOOT1 pin of the main control chip U1, and the other end of the twelfth resistor R12 is grounded (GND1);

[0132] One end of the third capacitor C3 is connected to the OSC_0 pin of the main control chip U1, and the other end of the third capacitor C3 is grounded (GND1);

[0133] One end of the second capacitor C2 is connected to the OCS_1 pin of the main control chip U1, and the other end of the second capacitor C2 is grounded (GND1);

[0134] One end of the thirteenth resistor R13 is connected between the OSC_0 pin of the main control chip U1 and the third capacitor C3, and the other end of the thirteenth resistor R13 is connected between the OCS_1 pin of the main control chip U1 and the second capacitor C2;

[0135] One end of the crystal oscillator Y1 is connected between the OSC_0 pin of the main control chip U1 and the third capacitor C3, and the other end of the crystal oscillator Y1 is connected between the OCS_1 pin of the main control chip U1 and the second capacitor C2.

[0136] It should be noted that the main control chip U1 can be a chip with the model number STM32F103. The resistance value of the ninth resistor R9 and the eleventh resistor R11 can be selected as 10 kΩ. The resistance value of the twelfth resistor R12 can be selected as 10 kΩ. The resistance value of the thirteenth resistor R13 can be selected as 1 MΩ. The capacitance value of the first capacitor C1 can be selected as 0.1 uF. The capacitance value of the second capacitor C2 can be selected as 24 pF. The capacitance value of the third capacitor C3 can be selected as 24 pF. The frequency of the crystal oscillator Y1 can be selected as 8 MHz.

[0137] In this embodiment, the optocoupler module includes a fourth optocoupler U2, an NMOS transistor Q1, an eighteenth resistor R18, a nineteenth resistor R19, a parameter resistor Rout, and a second diode D2.

[0138] The first pin of the fourth optocoupler U2 is connected to the PA0 pin of the main control chip U1 through the eighteenth resistor R18. The second pin of the fourth optocoupler U2 is grounded (GND1). The third pin of the fourth optocoupler U2 is connected to the gate of the NMOS transistor Q1.

[0139] One end of the nineteenth resistor R19 is connected between the third pin of the fourth optocoupler U2 and the gate of the NMOS transistor Q1, and the other end of the nineteenth resistor R19 is grounded (GND2).

[0140] One end of the parameter resistor Rout is connected to the source of the NMOS transistor Q1, and the other end of the parameter resistor Rout is grounded (GND2).

[0141] The drain of the NMOS transistor Q1 is connected to the second end of the load.

[0142] The positive electrode of the second diode D2 is respectively connected to the source of the NMOS transistor Q1 and the positive input terminal of the first operational amplifier U3, and the negative electrode of the second diode D2 is connected to the drain of the NMOS transistor Q1.

[0143] The fourth pin of the fourth optocoupler U2 is connected to the voltage EXT_5V.

[0144] It should be noted that the fourth optocoupler U2 can be an optocoupler with the model number TLP291. The NMOS transistor Q1 can be an NMOS transistor with the model number 50N06. The resistance value of the eighteenth resistor R18 can be selected as 1 kΩ. The resistance value of the nineteenth resistor R19 can be selected as 51 kΩ. The resistance value of the parameter resistor Rout can be selected as 10 Ω. The second diode D2 can be a diode with the model number IN4007.

[0145] In this embodiment, the load includes a relay and a first diode D1;

[0146] One end of the relay is respectively connected to the source electrode of the NMOS transistor Q1, the twenty-sixth resistor R26, and the positive electrode of the first diode D1, and the other end of the relay is respectively connected to the twenty-seventh resistor R27 and the negative electrode of the first diode D1.

[0147] It should be noted that the first diode D1 can be a diode with the model IN4007.

[0148] Implementation principle steps:

[0149] (1) The upper current limit set by the upper current limit comparison module is I max = 100 mA, then the first voltage reference source in the upper current limit comparison module is V ref1 = I max *R out *K1 = 0.1 * 10 * 2 = 2 V. If the output current of the optocoupler is greater than 100 mA, the isolation feedback module will input a low level to the PA1 pin of the main control module. If the output current of the optocoupler module is less than 100 mA, the isolation feedback module will input a high level to the PA1 of the main control module.

[0150] (2) The lower current limit set by the lower current limit comparison module is I min = 10 mA, then the second reference source in the lower current limit comparison module is V ref2 = I min *R out *K1 = 0.01 * 10 * 2 = 0.2 V. If the output current of the optocoupler is greater than 10 mA, the isolation feedback module will input a low level to the PA2 of the main control module. If the output current at the optocoupler end is less than 10 mA, the isolation feedback module will input a high level to the PA2 of the main control module.

[0151] (3) The short-circuit voltage set by the voltage comparison module is V short = 2 V, then the third reference source in the voltage comparison module is V ref3 = V short *K2 = 2 * 0.1 = 0.2 V. If the voltage across the load connected to the output end of the optocoupler module is greater than 2 V, the isolation feedback module will input a low level to the PA3 of the main control module. If the voltage across the load connected to the output end of the optocoupler module is less than 2 V, the isolation feedback module will input a high level to the PA3 of the main control module.

[0152] (4) When the main control module outputs a conduction signal to turn on the optocoupler module, the main control module reads the current upper limit comparison result, current lower limit comparison result, and voltage comparison result input by the isolation feedback module at this time. If the main control module reads that PA1 is at a high level, PA2 is at a low level, and PA3 is at a low level, it indicates that the output is normally conducting. If the main control module reads that PA1 is at a high level and PA2 is at a high level, it indicates that the output is cut off. If the main control module reads that PA1 is at a low level and PA2 is at a low level, it indicates that the output is overcurrent. If the main control module reads that PA2 is at a low level and PA3 is at a high level, it indicates that the output is short-circuited, so as to know whether the output end of the optocoupler module is normally conducting.

[0153] (5) When the main control module outputs a cut-off signal to turn off the optocoupler module, the main control module reads the current upper limit comparison result, current lower limit comparison result, and voltage comparison result input by the isolation feedback module at this time. If the main control module reads that PA1 is at a high level, PA2 is at a low level, and PA3 is at a low level, it indicates that the output is normally conducting. If the main control module reads that PA1 is at a high level and PA2 is at a high level, it indicates that the output is cut off. If the main control module reads that PA1 is at a low level and PA2 is at a low level, it indicates that the output is overcurrent. If the main control module reads that PA2 is at a low level and PA3 is at a high level, it indicates that the output is short-circuited, so as to know whether the output end of the optocoupler module is cut off.

[0154] Although terms such as main control module, optocoupler module, output detection module, isolation feedback module, and load are used more in this article, the possibility of using other terms is not excluded. The use of these terms is only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

[0155] An isolation feedback circuit for detecting the output state of an optocoupler provided by an embodiment of the present invention forms an isolation feedback circuit by a main control module, an output detection module, and an isolation feedback module, and quickly feeds back the output state of the output end of the optocoupler module to the main control module with simple level information, so that the main control module can clearly know the output state of the output end of the optocoupler module in real time, so as to timely learn about the abnormality of the output end of the optocoupler module, thereby reducing the impact on the normal output of the signal and avoiding causing safety problems.

[0156] So far, the description of the above embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or limiting of the disclosure. Individual elements or features of a particular embodiment are generally not limited by the particular embodiment, but when applicable, they can be interchanged and used in selected embodiments even if not specifically shown or described. In many respects, the same elements or features can also be changed. Such changes are not considered to deviate from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

[0157] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those skilled in the art. To thoroughly understand the embodiments of this disclosure, numerous specific details are set forth, such as examples of specific components, devices, and methods. Obviously, for those skilled in the art, specific details are not required, and the example embodiments may be implemented in many different forms, and neither should be construed as limiting the scope of this disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0158] Here, specific technical terms are used only for the purpose of describing specific example embodiments and are not intended for purposes of limitation. Unless the context clearly dictates otherwise, the singular forms "a" and "the" used herein may also be intended to include the plural forms. The terms "comprising" and "having" are inclusive and thus specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. Unless explicitly indicated the order of execution, the method steps, processes, and operations described herein are not to be construed as necessarily requiring to be executed in the specific order discussed and shown. It should also be understood that additional or alternative steps may be employed.

[0159] When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it can be directly on, engaged to, connected to, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element or layer is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship of elements should be interpreted in a like manner (e.g., “between” and “directly between,” “adjacent” and “directly adjacent,” etc.). The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections are not limited by these terms. These terms may only be used to distinguish one element, component, region, or section from another. Unless clearly indicated by the context, terms such as “first,” “second,” and other numerical terms used herein do not imply a sequence or order. Thus, a first element, component, region, layer, or section discussed below may be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0160] Spatial relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” etc., may be used herein for purposes of convenience in description to describe the relationship of one element or feature to another element or feature(s) as shown in the figures. Spatial relative terms may mean different orientations of the device in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as “beneath” or “below” another element or feature would then be oriented “above” the other element or feature. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial relative descriptions used herein interpreted accordingly.

Claims

1. An isolation feedback circuit for detecting the output state of an optocoupler, which is applied to an optocoupler module. The first input end of the optocoupler module is connected to a load, and is characterized in that, The circuit includes a main control module, an output detection module, and an isolation feedback module; among them, the output detection module includes a current detection module, a current upper limit comparison module, a current lower limit comparison module, a voltage detection module, and a voltage comparison module; the second input end of the optocoupler module is connected to the output end of the main control module, and the output end of the optocoupler module is connected to the input end of the current detection module; the output end of the current detection module is respectively connected to the input end of the current upper limit comparison module and the input end of the current lower limit comparison module; the input end of the voltage detection module is connected in parallel with the load, and the output end of the voltage detection module is connected to the input end of the voltage comparison module; the output end of the current upper limit comparison module is connected to the first input end of the isolation feedback module, the output end of the current lower limit comparison module is connected to the second input end of the isolation feedback module, and the output end of the voltage comparison module is connected to the third input end of the isolation feedback module; the output end of the isolation feedback module is connected to the input end of the main control module; the current detection module is used to detect the load current at the output end of the optocoupler module and supply the load current to the current upper limit comparison module and the current lower limit comparison module; the current upper limit comparison module is used to compare the load current with a set current upper limit to determine whether the load current exceeds the current upper limit, so as to obtain a current upper limit comparison result; the current lower limit comparison module is used to compare the load current with a set current lower limit to determine whether the load current reaches the current lower limit, so as to obtain a current lower limit comparison result; the voltage detection module is used to detect the load voltage at the output end of the optocoupler module and supply the load voltage to the voltage comparison module; the voltage comparison module is used to compare the load voltage with a set short-circuit voltage to determine whether the load voltage reaches the short-circuit voltage, so as to obtain a voltage comparison result; the main control module is used to output a conduction signal to turn on the optocoupler module, and read the current upper limit comparison result, current lower limit comparison result, and voltage comparison result input by the isolation feedback module, so as to know whether the output end of the optocoupler module is conducting; and, it is used to output a cut-off signal to turn off the optocoupler module, and read the current upper limit comparison result, current lower limit comparison result, and voltage comparison result input by the isolation feedback module, so as to know whether the output end of the optocoupler module is cut off.

2. The isolation feedback circuit for detecting the output state of the optocoupler according to claim 1, wherein the current detection module includes a first operational amplifier U3, a first resistor R1, and a third resistor R3; the positive input end of the first operational amplifier U3 is connected to the optocoupler module, the negative input end of the first operational amplifier U3 is grounded through the first resistor R1, and the output end of the first operational amplifier U3 is connected to the current upper limit comparison module; one end of the third resistor R3 is connected to the output end of the first operational amplifier U3, and the other end of the third resistor R3 is connected between the negative input end of the first operational amplifier U3 and the first resistor R1.

3. The isolation feedback circuit for detecting the output state of the optocoupler according to claim 2, characterized in that, The current upper limit comparison module includes a first voltage comparator U5, a fourteenth resistor R14, a fifteenth resistor R15, and a first voltage reference source VREF1; One end of the fourteenth resistor R14 is connected to the power supply terminal of the first voltage comparator U5, and the other end of the fourteenth resistor R14 is connected to one end of the fifteenth resistor R15; the other end of the fifteenth resistor R15 is grounded; The positive input terminal of the first voltage comparator U5 is connected to the first voltage reference source VREF1 and then connected between the fourteenth resistor R14 and the fifteenth resistor R15; The negative input terminal of the first voltage comparator U5 is connected to the output terminal of the first operational amplifier U3; The output terminal of the first voltage comparator U5 is connected to the first input terminal of the isolation feedback module.

4. The isolation feedback circuit for detecting the output state of the optocoupler according to claim 3, wherein The current lower limit comparison module includes a second voltage comparator U6, a sixteenth resistor R16, a seventeenth resistor R17, and a second voltage reference source VREF2; One end of the sixteenth resistor R16 is connected to the power supply terminal of the second voltage comparator U6, and the other end of the sixteenth resistor R16 is connected to one end of the seventeenth resistor R17; the other end of the seventeenth resistor R17 is grounded; The positive input terminal of the second voltage comparator U6 is connected to the second voltage reference source VREF2 and then connected between the sixteenth resistor R16 and the seventeenth resistor R17; The negative input terminal of the second voltage comparator U6 is connected to the output terminal of the first operational amplifier U3; The output terminal of the second voltage comparator U6 is connected to the second input terminal of the isolation feedback module.

5. The isolation feedback circuit for detecting the output state of the optocoupler according to claim 4, characterized in that, The voltage detection module includes a second operational amplifier U4, a twenty-sixth resistor R26, a twenty-seventh resistor R27, a twenty-eighth resistor R28, and a twenty-ninth resistor R29; The positive input terminal of the second operational amplifier U4 is connected to the first end of the load through the twenty-seventh resistor R27, the negative input terminal of the second operational amplifier U4 is connected to the second end of the load through the twenty-sixth resistor R26, and the output terminal of the second operational amplifier U4 is connected to the input terminal of the voltage comparison module; One end of the twenty-eighth resistor R28 is connected between the second operational amplifier U4 and the twenty-sixth resistor R26, and the other end of the twenty-eighth resistor R28 is connected to the output terminal of the second operational amplifier U4; One end of the twenty-ninth resistor R29 is connected between the second operational amplifier U4 and the twenty-seventh resistor R27, and the other end of the twenty-ninth resistor R29 is grounded.

6. The isolation feedback circuit for detecting the output state of the optocoupler according to claim 5, wherein The voltage comparison module includes a third voltage comparator U7, a twentieth resistor R20, a twenty-first resistor R21, and a third voltage reference source VREF3; One end of the twentieth resistor R20 is connected to the power supply terminal of the third voltage comparator U7, and the other end of the twentieth resistor R20 is connected to one end of the twenty-first resistor R21; the other end of the twenty-first resistor R21 is grounded; The positive input terminal of the third voltage comparator U7 is connected to the third voltage reference source VREF3 and then connected between the twentieth resistor R20 and the twenty-first resistor R21; The negative input terminal of the third voltage comparator U7 is connected to the output terminal of the second operational amplifier U4; The output terminal of the third voltage comparator U7 is connected to the third input terminal of the isolation feedback module.

7. The isolation feedback circuit for detecting the output state of the optocoupler according to claim 6, characterized in that, The isolation feedback module includes a first optocoupler U8, a second optocoupler U9, a third optocoupler U10, an isolation chip U11, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a twenty-fourth resistor R24, and a twenty-fifth resistor R25; The first pin of the first optocoupler U8 is connected to one end of the fifth resistor R5, the second pin of the first optocoupler U8 is connected to the output terminal of the first voltage comparator U5, the third pin of the first optocoupler U8 is grounded, and the fourth pin of the first optocoupler U8 is respectively connected to one end of the seventh resistor R7 and the input terminal of the main control module; The first pin of the second optocoupler U9 is connected to one end of the sixth resistor R6, the second pin of the second optocoupler U9 is connected to the output terminal of the first voltage comparator U5, the third pin of the second optocoupler U9 is grounded, and the fourth pin of the second optocoupler U9 is respectively connected to one end of the eighth resistor R8 and the input terminal of the main control module; The first pin of the third optocoupler U10 is connected to one end of the twenty-fourth resistor R24, the second pin of the third optocoupler U10 is connected to the output terminal of the first voltage comparator U5, the third pin of the third optocoupler U10 is grounded, and the fourth pin of the third optocoupler U10 is respectively connected to one end of the twenty-fifth resistor R25 and the input terminal of the main control module.

8. The isolation feedback circuit for detecting the output state of the optocoupler according to claim 7, characterized in that, The main control module includes a main control chip U1, a ninth resistor R9, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a first capacitor C1, a second capacitor C2, a third capacitor C3, and a crystal oscillator Y1; The PA0 pin of the main control chip U1 is connected to the first input terminal of the optocoupler module, the PA1 pin of the main control chip U1 is connected to the fourth pin of the first optocoupler U8, the PA2 pin of the main control chip U1 is connected to the fourth pin of the second optocoupler U9, and the PA3 pin of the main control chip U1 is connected to the fourth pin of the third optocoupler U10; One end of the eleventh resistor R11 is connected to the BOOT2 pin of the main control chip U1, and the other end of the eleventh resistor R11 is grounded; One end of the twelfth resistor R12 is connected to the BOOT1 pin of the main control chip U1, and the other end of the twelfth resistor R12 is grounded; One end of the third capacitor C3 is connected to the OSC_0 pin of the main control chip U1, and the other end of the third capacitor C3 is grounded; One end of the second capacitor C2 is connected to the OCS_1 pin of the main control chip U1, and the other end of the second capacitor C2 is grounded; One end of the thirteenth resistor R13 is connected between the OSC_0 pin of the main control chip U1 and the third capacitor C3, and the other end of the thirteenth resistor R13 is connected between the OCS_1 pin of the main control chip U1 and the second capacitor C2; One end of the crystal oscillator Y1 is connected between the OSC_0 pin of the main control chip U1 and the third capacitor C3, and the other end of the crystal oscillator Y1 is connected between the OCS_1 pin of the main control chip U1 and the second capacitor C2.

9. The isolation feedback circuit for detecting the output state of the optocoupler according to claim 8, characterized in that, The optocoupler module includes a fourth optocoupler U2, an NMOS transistor Q1, an eighteenth resistor R18, a nineteenth resistor R19, a parameter resistor Rout, and a second diode D2; The first pin of the fourth optocoupler U2 is connected to the PA0 pin of the main control chip U1 through the eighteenth resistor R18, the second pin of the fourth optocoupler U2 is grounded, and the third pin of the fourth optocoupler U2 is connected to the gate of the NMOS transistor Q1; One end of the nineteenth resistor R19 is connected between the third pin of the fourth optocoupler U2 and the gate of the NMOS transistor Q1, and the other end of the nineteenth resistor R19 is grounded; One end of the parameter resistor Rout is connected to the source of the NMOS transistor Q1, and the other end of the parameter resistor Rout is grounded; The drain of the NMOS transistor Q1 is connected to the second end of the load; The positive electrode of the second diode D2 is respectively connected to the source of the NMOS transistor Q1 and the positive input terminal of the first operational amplifier U3, and the negative electrode of the second diode D2 is connected to the drain of the NMOS transistor Q1.

10. The isolation feedback circuit for detecting the output state of the optocoupler according to claim 9, wherein, The load includes a relay and a first diode D1; One end of the relay is respectively connected to the source of the NMOS transistor Q1, the twenty-sixth resistor R26, and the positive electrode of the first diode D1, and the other end of the relay is respectively connected to the twenty-seventh resistor R27 and the negative electrode of the first diode D1.

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