Optocoupler circuit and electronic device

Abstract

The invention provides an optocoupler circuit and electronic equipment, and relates to the technical field of optocouplers. An optocoupler in the optocoupler circuit comprises a light-emitting diode, an anode of the light-emitting diode is connected with a first input end of the optocoupler, a cathode of the light-emitting diode is connected with a second input end of the optocoupler, and an input end of a constant current branch is connected with a signal input end. The output end of the constant current branch is connected with the first input end of the optocoupler so as to input a constant current signal to the light emitting diode; the constant current branch circuit further comprises a fifth resistor, the first end of the fifth resistor is connected with the second input end of the optocoupler, and the second end of the fifth resistor is grounded. According to the embodiment of the invention, the constant-current signal can be provided for the optocoupler through the constant-current branch, the stability and accuracy of the output of the optocoupler are ensured, the bias current of the light-emitting diode in the optocoupler is adjusted through the fifth resistor, the light-emitting intensity of the light-emitting diode is increased, the time required by the light-emitting diode to reach a stable state is shortened, and the response speed of the optocoupler is improved.

Description

Technical Field

[0001] The present application relates to the field of optocoupler technology, and more specifically, to an optocoupler circuit and an electronic device. Background Art

[0002] With the rapid development of information technology and network technology, optocouplers are increasingly used in intelligent control and monitoring functions. As an important electrical isolation component, optocouplers provide an effective electrical signal isolation solution. The basic principle of optocouplers is to use optical signals to transmit information between the light-emitting diode (LED) and the photosensitive receiver (such as a phototransistor) inside the optocoupler to achieve electrical isolation between input and output. This isolation mechanism effectively blocks potential current loops and protects sensitive electronic equipment from voltage shocks and electromagnetic interference.

[0003] However, the photosensitive receiver in the optocoupler can only be turned on when the intensity of the received light signal reaches the conditions required for it to be turned on, and the signal received by the light-emitting diode is easily affected by the environment or the devices connected to it, resulting in the optocoupler receiving the signal unable to maintain a constant current state, reducing the response speed of the optocoupler and affecting the stability and accuracy of the optocoupler output. Summary of the invention

[0004] The embodiments of the present application provide an optocoupler circuit and an electronic device, which can solve the problem that the signal received by the existing optocoupler cannot maintain a constant current state, reduce the response speed and response efficiency of the optocoupler, and affect the stability and accuracy of the optocoupler output. To achieve this purpose, the embodiments of the present application provide the following solutions.

[0005] According to one aspect of an embodiment of the present application, there is provided an optocoupler circuit, comprising: an optocoupler and a constant current branch, wherein the optocoupler comprises a light emitting diode, an anode of the light emitting diode is connected to a first input terminal of the optocoupler, a cathode of the light emitting diode is connected to a second input terminal of the optocoupler, an input terminal of the constant current branch is connected to a signal input terminal, and an output terminal of the constant current branch is connected to the first input terminal of the optocoupler to input a constant current signal to the light emitting diode;

[0006] The constant current branch further includes a fifth resistor, a first end of the fifth resistor is connected to the second input end of the optocoupler, and a second end of the fifth resistor is grounded.

[0007] In one possible implementation, the constant current branch includes a linear regulator and a first resistor, the first input terminal of the linear regulator is connected to a reference voltage source and the second end of the first resistor, the voltage end of the linear regulator and the first end of the first resistor are connected to the reference voltage source, and the output end of the linear regulator is connected to the first input end of the optocoupler.

[0008] In one possible implementation, the constant current branch includes a second resistor and a third capacitor, the first end of the second resistor is connected to the second end of the first resistor, the signal input end, and the first end of the third capacitor, and the second end of the third capacitor is grounded.

[0009] In one possible implementation, the optocoupler includes a phototransistor, the collector of the phototransistor is connected to the first output end of the optocoupler, the emitter of the phototransistor is connected to the second output end of the optocoupler, the optocoupler circuit also includes a discharge branch provided with a first Schottky diode and a third resistor, the first end of the third resistor is connected to the first output end of the optocoupler, the second end is connected to the cathode of the first Schottky diode, the anode of the first Schottky diode is connected to the first voltage source, and the second output end of the optocoupler is grounded.

[0010] In a possible implementation, the optocoupler circuit also includes a feedback voltage limiting branch including a first transistor, a fourth resistor, a sixth resistor, a seventh resistor and a sixth capacitor, the emitter of the first transistor is connected to the anode of the first Schottky diode, the base of the first transistor is connected to the first end of the third resistor, the collector of the first transistor is connected to the first end of the sixth resistor, the second end of the fourth resistor, and the second end of the sixth capacitor, the second end of the sixth resistor is grounded, the first end of the fourth resistor and the first end of the sixth capacitor are connected to the first end of the seventh resistor and the base of the phototransistor, and the second end of the seventh resistor is grounded.

[0011] In a possible implementation, an amplifier circuit is further included, wherein an input end of the amplifier circuit is connected to the base of the phototransistor to amplify the signal output by the optocoupler.

[0012] In one possible implementation, the amplification circuit includes: an operational amplifier and an eighth resistor, wherein the non-inverting input terminal of the operational amplifier is grounded, the inverting input terminal is connected to the base of the phototransistor and the first end of the eighth resistor, and the second end of the eighth resistor is connected to the output terminal of the operational amplifier.

[0013] In one possible implementation, the amplification circuit includes a seventh capacitor, an eighth capacitor, and a tenth capacitor, the first end of the tenth capacitor is connected to the base of the phototransistor, the second end is connected to the inverting input terminal of the operational amplifier and the first end of the seventh capacitor, and the second end of the seventh capacitor is connected to the output terminal of the operational amplifier and the first end of the eighth capacitor.

[0014] In one possible implementation, the amplification circuit includes a tenth resistor and an eleventh resistor, the first end of the tenth resistor is connected to the base of the phototransistor, the first end of the eleventh resistor is connected to the second end of the tenth resistor, and the second end of the eleventh resistor is connected to the inverting input terminal of the operational amplifier.

[0015] According to one aspect of an embodiment of the present application, an electronic device is provided, wherein the electronic device includes the optocoupler circuit as described above.

[0016] The beneficial effects of the technical solution provided by the embodiment of the present application are:

[0017] The optocoupler circuit provided in the present application includes a light-emitting diode, the anode of the light-emitting diode is connected to the first input terminal of the optocoupler, the cathode of the light-emitting diode is connected to the second input terminal of the optocoupler, the input terminal of the constant current branch is connected to the signal input terminal, and the output terminal of the constant current branch is connected to the first input terminal of the optocoupler to input a constant current signal to the light-emitting diode; the constant current branch also includes a fifth resistor, the first end of the fifth resistor is connected to the second input terminal of the optocoupler, and the second end of the fifth resistor is grounded. The embodiment of the present application can provide a constant current signal to the optocoupler through the constant current branch to ensure the stability and accuracy of the optocoupler output, and use the fifth resistor to adjust the bias current of the light-emitting diode in the optocoupler, increase its luminous intensity, reduce the time required for the light-emitting diode to reach a stable state, and improve the response speed of the optocoupler. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in describing the embodiments of the present application.

[0019] Figure 1 A circuit diagram of an optocoupler circuit provided in an embodiment of the present application;

[0020] Figure 2 A circuit diagram of a first filter circuit and a second filter circuit in an optocoupler circuit provided in an embodiment of the present application;

[0021] Figure 3 This is a structural diagram of the electronic device of this application.

[0022] Description of Figure Numbers:

[0023] R5, the fifth resistor; U1, a linear regulator; R1, the first resistor; R2, the second resistor; C3, the third capacitor; D1, the first Schottky diode; R3, the third resistor; Q1, the first transistor; R4, the fourth resistor; R6, the sixth resistor; R7, the seventh resistor; C6, the sixth capacitor; U3A, an operational amplifier; R8, the eighth resistor; C9, the ninth capacitor; C11, the eleventh capacitor; C7, the seventh capacitor; C8, the eighth capacitor; C10, the tenth capacitor; R10, the tenth resistor; R11, the eleventh resistor; C1, the first capacitor; C2, the second capacitor; C4, the fourth capacitor; C5, the fifth capacitor. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described below in conjunction with the drawings in the present application. It should be understood that the implementation methods described below in conjunction with the drawings are exemplary descriptions for explaining the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions of the embodiments of the present application.

[0025] It will be understood by those skilled in the art that, unless specifically stated, the singular forms "one", "said", and "the" used herein may also include plural forms. It should be further understood that the terms "including" and "comprising" used in the embodiments of the present application refer to that the corresponding features can be implemented as the presented features, information, data, steps, operations, elements and / or components, but do not exclude the implementation of other features, information, data, steps, operations, elements, components and / or combinations thereof supported by the present technical field. It should be understood that when we say that an element is "connected" or "coupled" to another element, the one element may be directly connected or coupled to the other element, or it may refer to that the one element and the other element establish a connection relationship through an intermediate element. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and / or" used herein indicates at least one of the items defined by the term, for example, "A and / or B" indicates that it is implemented as "A", or is implemented as "A", or is implemented as "A and B".

[0026] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0027] The following describes several exemplary embodiments to illustrate the technical solutions of the embodiments of the present application and the technical effects produced by the technical solutions of the present application. It should be noted that the following embodiments can refer to, draw on or combine with each other, and the same terms, similar features and similar implementation steps in different embodiments will not be described repeatedly.

[0028] The optocoupler circuit and electronic device provided in the present application are intended to solve at least one technical problem existing in the prior art.

[0029] An optical coupler circuit is provided in an embodiment of the present application. Figure 1-Figure 2 As shown, the optocoupler circuit includes: an optocoupler, a constant current branch, the optocoupler includes a light emitting diode, the anode of the light emitting diode is connected to the first input end of the optocoupler, the cathode of the light emitting diode is connected to the second input end of the optocoupler, the input end of the constant current branch is connected to the signal input end, and the output end of the constant current branch is connected to the first input end of the optocoupler to input a constant current signal to the light emitting diode; the constant current branch also includes a fifth resistor R5, the first end of the fifth resistor R5 is connected to the second input end of the optocoupler, and the second end of the fifth resistor R5 is grounded. Wherein, the bias current of the light emitting diode is shunted by the fifth resistor R5, and the resistance value of the fifth resistor R5 can correspond to the luminous intensity of the light emitting diode. The resistance value of the fifth resistor R5 can be adjusted according to actual needs, and after the adjustment is completed, the fixed resistance value is maintained. The bias current of the light emitting diode in the optocoupler is adjusted by the fifth resistor R5, the luminous intensity of the LED is increased, thereby improving the light signal receiving efficiency of the photosensitive receiver, and the time required for it to reach a stable luminous state can be reduced, thereby shortening the response time of the optocoupler and improving the response speed. Furthermore, when the optocoupler needs to be turned off, the fifth resistor R5 can quickly reduce the voltage of the light emitting diode, so that the light emitting diode is quickly turned off.

[0030] Optionally, the current resistance of the fifth resistor R5 can be calculated according to the following formula:

[0031]

[0032] Among them, V LED is the forward voltage of the light-emitting diode, I 分流 is the current that we want to shunt, R LED is the forward bias resistance of the light emitting diode, R 分流 is the resistance value of the fifth resistor R5.

[0033] Optionally, the constant current branch includes a linear regulator U1, a first resistor R1, a first input end of the linear regulator U1 is connected to a reference voltage source and a second end of the first resistor R1, a voltage end of the linear regulator U1 and a first end of the first resistor R1 are connected to the reference voltage source, and an output end of the linear regulator U1 is connected to a first input end of an optocoupler. A constant current signal is provided to the optocoupler through the linear regulator U1 to ensure the stability and accuracy of the optocoupler output. The constant current branch can provide a stable and accurate driving current for the optocoupler, ensuring that the light-emitting diode in the optocoupler works in an optimal state, emits light quickly and stably, thereby laying the foundation for improving the response speed. The current size and stability of the constant current source are accurately controlled by the fifth resistor R5, so that the luminous intensity of the light-emitting diode can quickly reach the desired level, reducing the startup time.

[0034] Optionally, the voltage of the reference voltage source is consistent with the working voltage of the linear regulator U1. Specifically, the voltage of the reference voltage source may be 3.3V, and the working voltage is provided to the linear regulator U1 through the reference voltage source.

[0035] Optionally, the second input terminal of the linear regulator U1 is connected to the first terminal of the fifth resistor R5 and the second input terminal of the optocoupler.

[0036] In one embodiment, the constant current branch also includes a second resistor R2 and a third capacitor C3, the first end of the second resistor R2 is connected to the second end of the first resistor R1, the signal input end, and the first end of the third capacitor C3, and the second end of the third capacitor C3 is grounded.

[0037] Optionally, the photosensitive receiver in the optocoupler is a phototransistor, the collector of the phototransistor is connected to the first output end of the optocoupler, the emitter of the phototransistor is connected to the second output end of the optocoupler, and the optocoupler circuit also includes a discharge branch provided with a first Schottky diode D1 and a third resistor R3, the first end of the third resistor R3 is connected to the first output end of the optocoupler, the second end is connected to the cathode of the first Schottky diode D1, the anode of the first Schottky diode D1 is connected to the first voltage source, and the second output end of the optocoupler is grounded. When using a phototransistor, the discharge branch can quickly discharge the charge accumulated in the collector, thereby accelerating the conversion of the photosensitive receiver from the on state to the off state. Rapid discharge can reduce signal fluctuations caused by the storage effect and improve the stability and reliability of the signal.

[0038] Optionally, the resistance value of the third resistor R3 can be set according to the discharge requirements of the phototransistor. The first Schottky diode has a very low reverse recovery time, and the low forward voltage drop is conducive to rapid discharge. The reverse withstand voltage of the first Schottky diode is higher than the maximum reverse voltage that the optocoupler may output at any time to prevent the first Schottky diode D1 from being damaged due to overvoltage breakdown.

[0039] Optionally, the optocoupler circuit also includes a feedback voltage limiting branch including a first transistor Q1, a fourth resistor R4, a sixth resistor R6, a seventh resistor R7 and a sixth capacitor C6, the emitter of the first transistor Q1 is connected to the anode of the first Schottky diode D1, the base of the first transistor Q1 is connected to the first end of the third resistor R3, the collector of the first transistor Q1 is connected to the first end of the sixth resistor R6, the second end of the fourth resistor R4, and the second end of the sixth capacitor C6, the second end of the sixth resistor R6 is grounded, the first end of the fourth resistor R4 and the first end of the sixth capacitor C6 are connected to the first end of the seventh resistor R7 and the base of the optocoupler, and the second end of the seventh resistor R7 is grounded.

[0040] The feedback voltage limiting branch and the optocoupler form a closed-loop control system. The feedback voltage limiting branch monitors the output voltage in real time and feeds back to the phototransistor to achieve precise control of the optocoupler output and reduce the sensitivity of the optocoupler branch to external interference. The output voltage of the optocoupler can be calculated according to the following formula:

[0041]

[0042] Among them, V OUT is the output voltage of the optocoupler, A 开环 is the open-loop gain, which refers to the amplification factor of the input signal to the output signal when there is no feedback, V 输入 is the input voltage of the phototransistor (which can be regarded as the voltage of the base of the phototransistor), is the initial voltage signal of the control system, and β is the feedback coefficient, which indicates the ratio of the feedback signal to the input signal. In a closed-loop control system, the feedback signal will reduce the system's response to input changes, thereby making the output voltage more stable. If A 开环 ×β approaches 1, then the system will tend to be stable because the feedback signal will offset most of the input changes. 开环 If ×β is much larger than 1, the system may become unstable because the feedback signal amplifies small changes in the input.

[0043] Optionally, the optocoupler circuit may also include an amplifier circuit, the input end of which is connected to the base of the phototransistor to amplify the signal output by the optocoupler. The signal output by the phototransistor is weak and needs to be amplified by the amplifier circuit to facilitate subsequent circuit processing or drive a larger load.

[0044] Optionally, the amplification circuit includes: an operational amplifier U3A, an eighth resistor R8, the in-phase input terminal of the operational amplifier U3A is grounded, the inverting input terminal is connected to the base of the phototransistor and the first terminal of the eighth resistor R8, and the second terminal of the eighth resistor R8 is connected to the output terminal of the operational amplifier U3A. The operational amplifier U3A is used to amplify the signal.

[0045] In one embodiment, the amplifier circuit further includes a ninth capacitor C9 and an eleventh capacitor C11, wherein the first end of the ninth capacitor C9 is connected to the positive power pin of the operational amplifier U3A and the positive power supply, and the second end of the ninth capacitor C9 is grounded. The first end of the eleventh capacitor C11 is connected to the negative power pin of the operational amplifier U3A and the negative power supply, and the second end of the eleventh capacitor C11 is grounded.

[0046] Optionally, in order to amplify only the AC signal, thereby isolating the DC component and preventing the subsequent circuit from being affected by the DC bias, the amplifier circuit includes a seventh capacitor C7, an eighth capacitor C8, and a tenth capacitor C10, wherein the first end of the tenth capacitor C10 is connected to the base of the phototransistor, the second end is connected to the inverting input end of the operational amplifier U3A and the first end of the seventh capacitor C7, and the second end of the seventh capacitor C7 is connected to the output end of the operational amplifier U3A and the first end of the eighth capacitor C8. The amplifier circuit improves the stability of the output signal and reduces the influence of external interference on the optocoupler circuit. For example, when the optocoupler is subjected to external electromagnetic interference and generates less noise, the circuit structure of the amplifier circuit can amplify a relatively large useful signal, while the increase in noise is relatively small, thereby improving the signal-to-noise ratio.

[0047] Optionally, the amplification circuit includes a tenth resistor R10 and an eleventh resistor R11, the first end of the tenth resistor R10 is connected to the base of the phototransistor, the first end of the eleventh resistor R11 is connected to the second end of the tenth resistor R10, and the second end of the eleventh resistor R11 is connected to the inverting input terminal of the operational amplifier U3A.

[0048] Optionally, the non-inverting input of the operational amplifier U3A is grounded, the voltage value is 0V, the inverting input and the non-inverting input are virtually shorted, so it is also 0V, the input resistance of the inverting input is very high, and it can be seen from the virtual disconnection that almost no current is injected into and flows out of the non-inverting input and the inverting input. Then R10, R11 and R8 are equivalent to being connected in series, and the current flowing through each component in a series circuit is the same, that is, the current flowing through R10, R11 and the current flowing through R8 are the same.

[0049] The current I1 flowing through R10 and R11 = (V i -(V-)) / (R10+R11); the current I2 flowing through R8 = ((V-)-V OUT ) / R8;

[0050] (V-) = (V+) = 0;

[0051] I1=I2;

[0052] Solving the algebraic equation above yields:

[0053] V OUT =-(R8 / (R10+R11))*V i

[0054] Among them, V i is the input voltage of the amplifier circuit, V- is the voltage of the inverting input terminal, V+ is the voltage of the non-inverting input terminal, V OUTis the output voltage of operational amplifier U3A. The amplifier circuit can enhance the signal output by the optocoupler, improve the strength and quality of the signal, reduce the loss and distortion of the signal during transmission and processing, and thus help improve the overall response speed. By using a high-performance amplifier and a reasonable amplification factor, the weak signal output by the optocoupler can be quickly amplified to a level that can be effectively processed by the subsequent circuit.

[0055] Optionally, in order to filter out the AC components in the input reference voltage source and the first voltage source, the optocoupler circuit also includes a first filter circuit and a second filter circuit, wherein the input end of the first filter circuit is connected to the reference voltage source and the output end is grounded, and the input end of the second filter circuit is connected to the first voltage source and the output end is grounded.

[0056] In one embodiment, the first filter circuit includes a first capacitor C1 and a second capacitor C2, wherein the first ends of the first capacitor C1 and the second capacitor C2 are connected to a reference voltage source, and the second ends of the first capacitor C1 and the second capacitor C2 are grounded. The second filter circuit includes a fourth capacitor C4 and a fifth capacitor C5, wherein the first ends of the fourth capacitor C4 and the fifth capacitor C5 are connected to a first voltage source, and the second ends of the fourth capacitor C4 and the fifth capacitor C5 are grounded.

[0057] Optionally, when the discharge circuit fails, the constant current branch can partially replace the function of reducing the output current of the discharge circuit by adjusting the output current through the linear regulator U1 to slow down the speed of charge accumulation, or in certain circumstances, temporarily increase the output current to produce a certain discharge effect. The voltage-limiting feedback branch can also act in time to limit the excessive voltage within a safe range and shunt the excess voltage to the ground or other suitable places to prevent other circuit components from being damaged due to overvoltage; the amplifier circuit is generally used to amplify the signal, but when the discharge circuit fails, its working state can be adjusted to indirectly affect the charge distribution of the circuit. For example, reducing the amplification factor can reduce the amplification effect on the input signal, thereby reducing the factors that may cause charge accumulation.

[0058] The present application uses a discharge branch, a voltage-limiting feedback branch, and an amplifier circuit to enable the phototransistor to quickly exit a deep saturation state, accelerate the discharge of the junction capacitance of the phototransistor, and greatly improve the output rate of the optocoupler and amplify a relatively large useful signal when the resistance of the output load is constant, while the increase in noise is relatively small, thereby improving the signal-to-noise ratio and the stability of the optocoupler, so that it can transmit and process signals more stably and accurately in various applications.

[0059] In an optional embodiment, an electronic device is provided, such as Figure 3 As shown, Figure 3 The electronic device shown includes the optocoupler circuit as described in the above embodiment.

[0060] Optionally, the electronic device may include an input module, the input module is provided with a power supply circuit, the reference voltage source and the first voltage source in the optocoupler circuit are connected to the power supply circuit, and the optocoupler circuit is powered by the power supply circuit. The input module may also serve as a signal input terminal of the optocoupler circuit, and the optocoupler circuit obtains an input signal through the signal input terminal.

[0061] Optionally, the electronic device may further include an output module provided with a signal transmission circuit, the output module is connected to the amplifying circuit, and the signal transmission circuit in the output module transmits the signal amplified by the amplifying circuit to a target object. The target object may be a load in the electronic device, or a mobile phone, a television, a washing machine, or other devices wirelessly connected to the electronic device.

[0062] The terms "first", "second", "third", "fourth", "1", "2", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that shown or described in the drawings.

[0063] It should be understood that, although each operation step is indicated by arrows in the flowchart of the embodiment of the present application, the implementation order of these steps is not limited to the order indicated by the arrows. Unless clearly stated herein, in some implementation scenarios of the embodiment of the present application, the implementation steps in each flowchart can be performed in other orders according to demand. In addition, some or all of the steps in each flowchart may include multiple sub-steps or multiple stages based on actual implementation scenarios. Some or all of these sub-steps or stages may be executed at the same time, and each sub-step or stage in these sub-steps or stages may also be executed at different times respectively. In different scenarios of execution time, the execution order of these sub-steps or stages may be flexibly configured according to demand, and the embodiment of the present application does not limit this.

[0064] The above is only an optional implementation method for some implementation scenarios of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the technical concept of the solution of the present application, other similar implementation methods based on the technical ideas of the present application are also within the protection scope of the embodiments of the present application.

Claims

1. An optocoupler circuit, characterized in that: include: An optical coupler and a constant current branch, wherein the optical coupler includes a light emitting diode, an anode of the light emitting diode is connected to a first input terminal of the optical coupler, a cathode of the light emitting diode is connected to a second input terminal of the optical coupler, an input terminal of the constant current branch is connected to a signal input terminal, and an output terminal of the constant current branch is connected to the first input terminal of the optical coupler to input a constant current signal to the light emitting diode; The constant current branch further includes a fifth resistor, a first end of the fifth resistor is connected to the second input end of the optocoupler, and a second end of the fifth resistor is grounded.

2. The optocoupler circuit according to claim 1, characterized in that: The constant current branch includes a linear regulator and a first resistor, the first input end of the linear regulator is connected to a reference voltage source and the second end of the first resistor, the voltage end of the linear regulator and the first end of the first resistor are connected to the reference voltage source, and the output end of the linear regulator is connected to the first input end of the optocoupler.

3. The optocoupler circuit according to claim 2, characterized in that: The constant current branch includes a second resistor and a third capacitor, the first end of the second resistor is connected to the second end of the first resistor, the signal input end, and the first end of the third capacitor, and the second end of the third capacitor is grounded.

4. The optocoupler circuit according to claim 1, characterized in that: The optocoupler includes a phototransistor, the collector of the phototransistor is connected to the first output end of the optocoupler, the emitter of the phototransistor is connected to the second output end of the optocoupler, the optocoupler circuit also includes a discharge branch provided with a first Schottky diode and a third resistor, the first end of the third resistor is connected to the first output end of the optocoupler, the second end is connected to the cathode of the first Schottky diode, the anode of the first Schottky diode is connected to the first voltage source, and the second output end of the optocoupler is grounded.

5. The optocoupler circuit according to claim 4, characterized in that: The optocoupler circuit also includes a feedback voltage limiting branch including a first transistor, a fourth resistor, a sixth resistor, a seventh resistor and a sixth capacitor, the emitter of the first transistor is connected to the anode of the first Schottky diode, the base of the first transistor is connected to the first end of the third resistor, the collector of the first transistor is connected to the first end of the sixth resistor, the second end of the fourth resistor and the second end of the sixth capacitor, the second end of the sixth resistor is grounded, the first end of the fourth resistor and the first end of the sixth capacitor are connected to the first end of the seventh resistor and the base of the phototransistor, and the second end of the seventh resistor is grounded.

6. The optocoupler circuit according to claim 4, characterized in that: It also includes an amplifier circuit, the input end of which is connected to the base of the phototransistor to amplify the signal output by the optical coupler.

7. The optocoupler circuit according to claim 6, characterized in that: The amplifying circuit comprises: an operational amplifier and an eighth resistor. The in-phase input terminal of the operational amplifier is grounded, the inverting input terminal is connected to the base of the phototransistor and the first terminal of the eighth resistor, and the second terminal of the eighth resistor is connected to the output terminal of the operational amplifier.

8. The optocoupler circuit according to claim 7, characterized in that: The amplification circuit includes a seventh capacitor, an eighth capacitor, and a tenth capacitor. The first end of the tenth capacitor is connected to the base of the phototransistor, the second end is connected to the inverting input terminal of the operational amplifier and the first end of the seventh capacitor, and the second end of the seventh capacitor is connected to the output terminal of the operational amplifier and the first end of the eighth capacitor.

9. The optocoupler circuit according to claim 7, characterized in that: The amplifying circuit includes a tenth resistor and an eleventh resistor, wherein the first end of the tenth resistor is connected to the base of the phototransistor, the first end of the eleventh resistor is connected to the second end of the tenth resistor, and the second end of the eleventh resistor is connected to the inverting input terminal of the operational amplifier.

10. An electronic device, characterized in that: The electronic device comprises the optocoupler circuit as described in any one of claims 1-9.

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