AC switch circuit and AC power supply

Abstract

The utility model discloses an alternating current switch circuit and an alternating current power supply, relates to the field of electronic circuits, and solves the problem that an existing alternating current switch control circuit is not suitable for a high-speed alternating current switch control occasion. AC signals form an access through the rectification circuit and the transistor, and the load is powered. When the controller stops sending the control signal, the optocoupler does not emit light, the control end of the transistor has no signal input, the transistor is switched off, the alternating current signal is cut off, and the load stops supplying power. Electrical isolation between the controller and the transistor is achieved through the optocoupler, and safety and stability of the circuit are improved. The transistor realizes high-speed switching operation, and the requirement of a high-speed alternating current switching circuit is met. According to the invention, a zero crossing point does not need to be judged, the switching-on and switching-off speed of the transistor is high, the control precision is improved, and some application scenes with extremely high switching speed requirements can be met.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuits, and in particular to an AC switching circuit and an AC power supply. Background Technology

[0002] In modern power electronic systems, AC switching circuits are widely used in many fields such as motor control, power conversion, and lighting dimming. Traditional AC switching circuits, such as mechanical relays and thyristors, have certain limitations in terms of switching speed, reliability, and control accuracy.

[0003] Mechanical relays have a slow switching speed due to their mechanical operation characteristics, typically in the millisecond range. Furthermore, the mechanical contacts are prone to wear and arcing during frequent opening and closing, affecting their service life and reliability, making them unsuitable for high-speed AC switching applications. While thyristors have a faster switching speed than mechanical relays, they require an additional commutation circuit when turning off and a zero-point detection circuit when turning on, resulting in a longer turn-off time. This makes them unsuitable for some applications with extremely high switching speed requirements.

[0004] Therefore, it is evident that how to solve the problem that existing AC switch control circuits are unsuitable for high-speed AC switch control applications is a technical problem that urgently needs to be solved by those in the field. Utility Model Content

[0005] The purpose of this invention is to provide an AC switching circuit and an AC power supply, thereby solving the problem that existing AC switch control circuits are not suitable for high-speed AC switch control applications.

[0006] To solve the above-mentioned technical problems, this utility model provides an AC switching circuit, including: an optocoupler, a transistor, a rectifier circuit, a first resistor, a second resistor, a first capacitor, and a controller;

[0007] The positive terminal of the optocoupler is connected to the control terminal of the controller, the negative terminal of the optocoupler is grounded, the collector of the optocoupler is connected to the power supply, the emitter of the optocoupler is connected to the first end of the first resistor and the control terminal of the transistor, the second end of the first resistor is grounded, the first end of the transistor is connected to the first end of the second resistor and the first output terminal of the rectifier circuit, the second end of the second resistor is connected to the first capacitor, the second end of the transistor is grounded and connected to the second end of the first capacitor and the second output terminal of the rectifier circuit, the first input terminal of the rectifier circuit is connected to the live wire port of the AC power supply, the second input terminal of the rectifier circuit is connected to the second end of the load, and the first end of the load is connected to the neutral wire port of the AC power supply.

[0008] As an optional solution, the above-mentioned AC switching circuit also includes: a power isolation circuit; the power isolation circuit includes: an isolation chip, a second capacitor, and a third capacitor;

[0009] The power input terminal of the isolation chip is connected to the power supply and the first terminal of the first capacitor. The ground terminal of the isolation chip is connected to and grounded to the second terminal of the first capacitor. The positive output terminal of the isolation chip is connected to the first terminal of the second capacitor. The 0V output terminal of the isolation chip is connected to the second terminal of the second capacitor. The positive output terminal of the isolation chip is connected to the collector of the optocoupler. The 0V output terminal of the isolation chip is connected to the second terminal of the first resistor and the second terminal of the transistor.

[0010] As an optional solution, the above-mentioned AC switching circuit also includes: an overvoltage protection circuit; the overvoltage protection circuit includes: a transient voltage suppression diode and a protection resistor;

[0011] The anode of the transient voltage suppression diode is connected to the first output terminal of the rectifier circuit, the cathode of the transient voltage suppression diode is connected to the second output terminal of the rectifier circuit, the first terminal of the protection resistor is connected to the cathode of the transient voltage suppression diode, and the second terminal of the protection resistor is grounded.

[0012] As an optional solution, the above-mentioned AC switching circuit also includes: a temperature detection circuit; the temperature detection circuit includes: a thermistor and a comparator;

[0013] The first terminal of the thermistor is connected to the power supply, and the second terminal of the thermistor is connected to the comparator.

[0014] The output of the comparator is connected to the temperature detection terminal of the controller.

[0015] As an optional solution, the temperature detection circuit in the above-mentioned AC switching circuit further includes an amplifier circuit;

[0016] The input terminal of the amplifier circuit is connected to the second terminal of the thermistor, and the output terminal of the amplifier circuit is connected to the input terminal of the comparator.

[0017] The controller receives the electrical signal amplified by the amplifier circuit after amplifying the resistance change of the thermistor.

[0018] As an optional solution, the aforementioned AC switching circuit also includes a fault detection circuit;

[0019] The fault detection circuit includes a current detection resistor and a fault detection chip;

[0020] The current sensing resistor is connected in series between the second output terminal of the rectifier circuit and the ground terminal. The input terminal of the fault detection chip is connected to both ends of the current sensing resistor, and the output terminal of the fault detection chip is connected to the fault detection terminal of the controller.

[0021] The fault detection circuit monitors the circuit current in real time. When the current is abnormal, the fault detection chip outputs a fault trigger signal to the controller.

[0022] As an optional solution, the above AC switching circuit includes a first diode, a second diode, a third diode, and a fourth diode;

[0023] The first diode, the second diode, the third diode, and the fourth diode constitute a bridge circuit.

[0024] To solve the above-mentioned technical problems, this utility model also provides an AC power supply, including the AC switching circuit described above.

[0025] The AC switching circuit provided by this utility model illuminates the optocoupler when the controller sends a control signal. Upon receiving the light signal, the control terminal of the transistor conducts, and the AC signal forms a path through the rectifier circuit and the transistor, supplying power to the load. When the controller stops sending control signals, the optocoupler stops illuminating, the control terminal of the transistor receives no signal input, the transistor turns off, the AC signal is cut off, and the load is no longer powered. The optocoupler achieves electrical isolation between the controller and the transistor, improving the circuit's safety and stability. The transistor enables high-speed switching operation, meeting the requirements of high-speed AC switching circuits. The RC circuit absorbs voltage fluctuation interference during transistor switching, protecting the transistor and the stable operation of the entire circuit. This application eliminates the need for a zero-crossing detection circuit and zero-crossing point determination. The transistor's turn-on and turn-off speeds are fast, resulting in simple and fast control, improved control accuracy, and the ability to meet the needs of applications with extremely high switching speed requirements.

[0026] In addition, this utility model also provides an AC power supply, including the above-mentioned AC switching circuit, with the same effect. Attached Figure Description

[0027] To more clearly illustrate the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of a switching circuit for a mechanical relay.

[0029] Figure 2This is a schematic diagram of a thyristor switching circuit;

[0030] Figure 3 This application provides an embodiment of an AC switching circuit. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0032] The core of this utility model is to provide an AC switching circuit and an AC power supply.

[0033] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Figure 1 This is a schematic diagram of a switching circuit for a mechanical relay. Figure 2 This is a schematic diagram of a thyristor switching circuit; such as Figure 1 As shown, the switching action is achieved by controlling the mechanical contacts through a mechanical relay J. Due to its mechanical operating characteristics, the switching speed of a mechanical relay is slow, typically in the millisecond range. Furthermore, the mechanical contacts are prone to wear and arcing during frequent opening and closing, affecting their service life and reliability, making them unsuitable for high-speed AC switching applications. Figure 2 As shown, switching action is achieved through thyristors. Although thyristors have a faster switching speed than mechanical relays, they require an additional commutation circuit when turning off and a zero-point detection circuit when turning on, resulting in a long turn-off time. This makes it difficult to meet the requirements of some application scenarios with extremely high switching speed requirements.

[0035] The AC switching circuit of this application embodiment is suitable for AC switching applications requiring high speed, reliability, and ease of control, such as motor control, power conversion, and lighting dimming. It is particularly suitable for applications requiring fast response and high control precision.

[0036] This embodiment provides an AC switching circuit, such as Figure 3 As shown, it includes:

[0037] Optocoupler U1, transistor Q1, rectifier circuit, first resistor R1, second resistor R2, first capacitor C1, controller;

[0038] The positive terminal of optocoupler U1 is connected to the control terminal of the controller, the negative terminal of optocoupler U1 is grounded, the collector of optocoupler U1 is connected to the power supply, the emitter of optocoupler U1 is connected to the first terminal of the first resistor R1 and the control terminal of transistor Q1, the second terminal of the first resistor R1 is grounded, the first terminal of transistor Q1 is connected to the first terminal of the second resistor R2 and the first output terminal of the rectifier circuit, the second terminal of the second resistor R2 is connected to the first capacitor C1, the second terminal of transistor Q1 is grounded and connected to the second terminal of the first capacitor C1 and the second output terminal of the rectifier circuit, the first input terminal of the rectifier circuit is connected to the live wire port of the AC power supply, the second input terminal of the rectifier circuit is connected to the second terminal of the load, and the first terminal of the load is connected to the neutral wire port of the AC power supply.

[0039] In this embodiment, the optocoupler U1 serves as an isolation element, typically composed of a photodiode and a phototransistor Q1. It achieves electrical isolation between the controller and transistor Q1, ensuring the safe transmission of control signals. The optocoupler U1 is connected to the controller via a control signal line to transmit control signals. The optocoupler U1 and transistor Q1 are connected to the control terminal of transistor Q1 through the emitter of the optocoupler U1 and the first resistor R1, achieving isolated signal transmission.

[0040] In this embodiment, a MOSFET is typically used as transistor Q1 due to its high-speed switching characteristics. As a switching element, it controls the on / off state of the AC signal. The on / off state of the AC signal is controlled based on the output signal of the optocoupler U1.

[0041] In this embodiment, the rectifier circuit may be a bridge rectifier circuit composed of diodes, used to convert AC power to DC power (in this example, more likely to ensure that transistor Q1 operates with the correct polarity). This ensures that the AC power supply can correctly drive transistor Q1 during both the positive and negative half-cycles. The rectifier circuit is connected to the AC power supply and the load. The first input terminal of the rectifier circuit is connected to the live wire of the AC power supply, the second input terminal is connected to the second terminal of the load, and the first terminal of the load is connected to the neutral wire of the AC power supply, forming a complete AC circuit.

[0042] The controller may be a microcontroller, a DSP (digital signal processor), or a dedicated control chip. It sends control signals to control the switching on and off of transistor Q1 via optocoupler U1.

[0043] When the controller sends a control signal, optocoupler U1 emits light. Upon receiving the light signal, the control terminal of transistor Q1 conducts, and the AC signal forms a path through the rectifier circuit and transistor Q1, supplying power to the load. When the controller stops sending control signals, optocoupler U1 stops emitting light, the control terminal of transistor Q1 receives no signal input, transistor Q1 turns off, the AC signal is cut off, and the load is no longer powered.

[0044] To ensure high-speed response and reliability of the circuit, transistor Q1 must be a MOSFET or other similar device with fast turn-on and turn-off capabilities. The specific values ​​of components such as resistors and capacitors can be adjusted according to actual application requirements to adapt to different operating conditions.

[0045] In the AC switching circuit provided in this embodiment, when the controller sends a control signal, the optocoupler U1 emits light, and the control terminal of transistor Q1 conducts after receiving the light signal. The AC signal forms a path through the rectifier circuit and transistor Q1, and the load is powered. When the controller stops sending control signals, the optocoupler U1 does not emit light, the control terminal of transistor Q1 has no signal input, transistor Q1 is turned off, the AC signal is cut off, and the load is no longer powered. The optocoupler U1 achieves electrical isolation between the controller and transistor Q1, improving the safety and stability of the circuit. Transistor Q1 achieves high-speed switching operation, meeting the requirements of high-speed AC switching circuits. The RC circuit absorbs voltage fluctuation interference during transistor Q1 switching, protecting transistor Q1 and the stable operation of the entire circuit. This application does not require a zero-crossing detection circuit or zero-crossing point determination. The turn-on and turn-off speeds of transistor Q1 are fast; therefore, the control is simple, fast, and improves control accuracy, meeting the needs of some application scenarios with extremely high switching speed requirements.

[0046] Furthermore, in one specific embodiment, it further includes: a power isolation circuit; the power isolation circuit includes: an isolation chip U2, a second capacitor C2, and a third capacitor C3;

[0047] The power input terminal of the isolation chip U2 is connected to the power supply and the first terminal of the first capacitor C1. The ground terminal of the isolation chip U2 is connected to the second terminal of the first capacitor C1 and grounded. The positive output terminal of the isolation chip U2 is connected to the first terminal of the second capacitor C2. The 0V output terminal of the isolation chip U2 is connected to the second terminal of the second capacitor C2. The positive output terminal of the isolation chip U2 is connected to the collector of the optocoupler U1. The 0V output terminal of the isolation chip U2 is connected to the second terminal of the first resistor R1 and the second terminal of the transistor Q1.

[0048] This embodiment adds a power isolation circuit to the original AC switching circuit. It consists of an isolation chip U2, a second capacitor C2, and a third capacitor C3. Its core function is to provide a stable DC voltage for low-voltage control components such as optocoupler U1 and controller, and solve the problem of control signal distortion caused by AC power fluctuations or unstable DC voltage after rectification.

[0049] The power input terminal of the isolation chip U2 is directly connected to the power supply. The first capacitor C1 serves as an input filter capacitor to absorb voltage fluctuations after rectification (such as 100Hz ripple) and prevent sudden changes in input voltage from affecting the isolation chip U2.

[0050] The positive output terminal of the isolation chip U2 is connected to the collector of the optocoupler U1 to provide a stable operating voltage (such as 5V) for the optocoupler U1. This ensures that the driving voltage of the LED of the optocoupler U1 remains constant, avoiding changes in the transfer ratio (CTR) of the optocoupler U1 due to voltage fluctuations, which would affect the accuracy of the control signal.

[0051] The output terminal of the isolation chip U20V is connected to the second terminal of the first resistor R1 and the second terminal (i.e., the ground terminal) of the transistor Q1. This unifies the reference ground potential of the control loop and the power loop, avoiding "ground bounce" noise interference with the control signal.

[0052] Furthermore, in one specific embodiment, it further includes: an overvoltage protection circuit; the overvoltage protection circuit includes: a transient voltage suppression diode and a protection resistor;

[0053] The anode of the transient voltage suppressor diode is connected to the first output terminal of the rectifier circuit, the cathode of the transient voltage suppressor diode is connected to the second output terminal of the rectifier circuit, the first terminal of the protection resistor is connected to the cathode of the transient voltage suppressor diode, and the second terminal of the protection resistor is grounded.

[0054] The anode of the transient voltage suppressor diode (TVS) is connected to the first output terminal (usually positive) of the rectifier circuit, and the cathode is connected to the second output terminal (usually negative) of the rectifier circuit. This connection method allows the TVS to respond quickly and clamp the voltage to a safe level when an overvoltage occurs in the circuit.

[0055] TVS is a commonly used overvoltage protection component that can limit excessive voltage to a safe threshold within a very short time (nanosecond level), thereby protecting downstream circuits from damage.

[0056] The first terminal of the protective resistor is connected to the cathode of the TVS diode, and the second terminal is grounded. The main function of the protective resistor is to limit the current flowing through the TVS diode when it is conducting, preventing damage due to overcurrent. It provides additional current limiting, protecting the TVS diode from damage caused by excessive current during overvoltage events. Simultaneously, it also helps to safely guide excess voltage and current to ground after the TVS diode has turned on.

[0057] When the output voltage of the rectifier circuit is within the normal range, the TVS is in the off state and does not conduct, and the circuit works normally. Once the output voltage exceeds the breakdown voltage of the TVS, the TVS will quickly conduct, clamping the voltage near its breakdown voltage. At the same time, the protection resistor limits the conduction current to prevent damage to the TVS and subsequent circuits. In this way, the overvoltage protection circuit can effectively protect the rectifier circuit and its subsequent circuits from damage caused by excessive voltage.

[0058] Furthermore, in one specific embodiment, it further includes: a temperature detection circuit; the temperature detection circuit includes: a thermistor and a comparator;

[0059] The first terminal of the thermistor is connected to the power supply, and the second terminal of the thermistor is connected to the comparator.

[0060] The comparator's output is connected to the controller's temperature sensing terminal.

[0061] The first terminal of the thermistor is connected to the power supply, and the second terminal is connected to one input terminal of the comparator. The resistance of the thermistor changes with temperature, thus it can be used as a temperature sensor. A thermistor is a temperature sensor whose resistance changes with temperature. In a temperature detection circuit, the thermistor converts the temperature change into a change in resistance, and then into a change in voltage or current, which is then compared by the comparator.

[0062] One input of the comparator is connected to a thermistor, and the other input is typically connected to a reference voltage. The comparator's output is connected to the temperature sensor on the controller. The comparator compares the signal generated by the thermistor with the reference voltage. As the thermistor's resistance changes with temperature, its generated voltage signal also changes. If this voltage signal exceeds the reference voltage, the comparator outputs a high or low level signal, indicating that the temperature has exceeded a set threshold.

[0063] When the temperature changes, the resistance of the thermistor changes accordingly, thus altering the voltage across its terminals. This voltage signal is sent to one input of a comparator and compared with a reference voltage. If an increase in temperature causes the thermistor's resistance to decrease, resulting in a lower voltage across it, and this voltage falls below the reference voltage, the comparator outputs a signal (e.g., a low level) to the controller's temperature detection terminal. Conversely, if a decrease in temperature causes the thermistor's resistance to increase, resulting in a higher voltage across it, and this voltage rises above the reference voltage, the comparator also outputs a signal (e.g., a high level) to the controller's temperature detection terminal. In this way, the controller can determine the current temperature state based on the comparator's output signal and take appropriate control measures.

[0064] Excessive temperatures can degrade the performance of electronic components or even damage them. By monitoring the temperature in real time and taking appropriate control measures, the stable and safe operation of electronic devices can be ensured. Furthermore, temperature detection circuits can be used to implement various temperature control functions, such as constant temperature control and overheat protection.

[0065] Furthermore, in one specific embodiment, the temperature detection circuit also includes an amplifier circuit;

[0066] The input terminal of the amplifier circuit is connected to the second terminal of the thermistor, and the output terminal of the amplifier circuit is connected to the input terminal of the comparator.

[0067] The controller receives the electrical signal after the amplification circuit amplifies the resistance change of the thermistor.

[0068] The main function of the amplifier circuit is to amplify the weak resistance change signal generated by the thermistor due to temperature variations, so that the subsequent comparator can more accurately detect and process this signal. The input terminal of the amplifier circuit is connected to the second terminal (i.e., the non-power supply terminal) of the thermistor, thus converting the resistance change of the thermistor into a voltage or current signal that is input to the amplifier circuit. The output terminal of the amplifier circuit is then connected to the input terminal of the comparator, transmitting the amplified signal to the comparator for further processing.

[0069] When the temperature changes, the resistance of the thermistor changes accordingly, thus altering the voltage across it or the current flowing through it. This minute change signal is sent to the input of an amplifier circuit, where it is amplified into a larger voltage or current signal and output to the input of a comparator. The comparator then compares this signal with a reference voltage and outputs a corresponding signal to the controller based on the comparison result. The amplifier circuit plays a crucial role in the temperature detection circuit. Because the resistance change of the thermistor is usually very small, without an amplifier circuit, this signal may be difficult for subsequent circuits to accurately detect and process. Therefore, by introducing an amplifier circuit, the accuracy and reliability of temperature detection can be greatly improved.

[0070] The controller receives an amplified electrical signal from the thermistor's resistance change, and uses this signal to determine the current temperature. If the temperature exceeds a set threshold, the controller can take appropriate control measures, such as alarm or shutdown, to protect the equipment from overheating damage.

[0071] An amplifier circuit can amplify the weak signal generated by a thermistor due to temperature changes, so that subsequent circuits can detect and process the signal more accurately, thereby improving the accuracy and reliability of temperature detection.

[0072] Furthermore, in one specific embodiment, a fault detection circuit is also included;

[0073] The fault detection circuit includes a current sensing resistor and a fault detection chip;

[0074] The current sensing resistor is connected in series between the second output terminal of the rectifier circuit and the ground terminal. The input terminal of the fault detection chip is connected to both ends of the current sensing resistor, and the output terminal of the fault detection chip is connected to the fault detection terminal of the controller.

[0075] The fault detection circuit monitors the circuit current in real time. When the current is abnormal, the fault detection chip outputs a fault trigger signal to the controller.

[0076] A current-sensing resistor is connected in series between the second output terminal of the rectifier circuit and ground. This ensures that all current in the circuit flows through this resistor, allowing the sensing circuit to measure the current magnitude. By measuring the voltage drop across the current-sensing resistor, the magnitude of the current in the circuit can be indirectly calculated. If the current is abnormal (e.g., too high or too low), this voltage drop will change accordingly.

[0077] The input terminal of the fault detection chip is connected to both ends of the current sensing resistor to receive the voltage signal generated by the current sensing resistor. The output terminal of the fault detection chip is connected to the fault detection terminal of the controller to output a fault trigger signal. The fault detection chip is responsible for monitoring the voltage signal generated by the current sensing resistor in real time to determine whether the current in the circuit is abnormal. If an abnormal current is detected, the fault detection chip will immediately output a fault trigger signal to the controller.

[0078] When the current in the circuit is normal, the voltage drop generated by the current sensing resistor is within a predetermined range. The fault detection chip continuously monitors this voltage drop and compares it with a preset threshold. If the voltage drop exceeds the threshold (indicating that the current is too high or too low), the fault detection chip will determine that the current is abnormal and output a fault trigger signal to the controller. After receiving the fault trigger signal, the controller can take corresponding fault handling measures, such as shutdown, alarm, or switching to the backup circuit, to ensure the safe operation of the equipment.

[0079] The fault detection circuit can monitor the current in the circuit in real time and issue an alarm promptly when an abnormality occurs. This helps prevent safety hazards such as equipment damage or fire caused by excessive current. At the same time, by taking timely fault handling measures, it can also minimize equipment downtime and maintenance costs.

[0080] Furthermore, in one specific embodiment, the diodes are: a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4.

[0081] The first diode D1, the second diode D2, the third diode D3, and the fourth diode D4 form a bridge circuit.

[0082] A bridge circuit consists of four diodes: D1, D2, D3, and D4. These four diodes are connected in a specific way to form a "bridge"-shaped circuit structure. Specifically, the cathodes of D1 and D2 are connected, forming one node; simultaneously, the anodes of D3 and D4 are connected, forming another node. The input or output terminal of the circuit is connected between these two nodes (depending on the specific application of the bridge circuit). Furthermore, the anode of D1 is connected to the cathode of D3, and the anode of D2 is connected to the cathode of D4; these two connections constitute the other two sides of the bridge circuit.

[0083] Bridge circuits are commonly used to convert alternating current (AC) to direct current (DC), i.e., for rectification. When AC is input to a bridge circuit, due to the unidirectional conductivity of diodes, only diodes with a forward bias will conduct, allowing current to flow. In this way, both the negative and positive half-cycles of the AC current are converted into the positive half-cycle (or negative half-cycle, depending on the diode connections) of the DC current, thus achieving rectification. In some applications, bridge circuits can also be used to adjust voltage. By changing the parameters of certain components in the bridge circuit (such as resistors and capacitors), the output voltage can be adjusted.

[0084] Finally, this application provides an AC power supply, including the aforementioned AC switching circuit. When the controller sends a control signal, the optocoupler U1 emits light, and the control terminal of transistor Q1 conducts after receiving the light signal. The AC signal forms a path through the rectifier circuit and transistor Q1, supplying power to the load. When the controller stops sending control signals, the optocoupler U1 does not emit light, the control terminal of transistor Q1 receives no signal input, transistor Q1 turns off, the AC signal is cut off, and the load is no longer supplied with power. The optocoupler U1 achieves electrical isolation between the controller and transistor Q1, improving the safety and stability of the circuit. Transistor Q1 achieves high-speed switching operation, meeting the requirements of high-speed AC switching circuits. The RC circuit absorbs voltage fluctuation interference during transistor Q1 switching, protecting transistor Q1 and the stable operation of the entire circuit. This application does not require a zero-crossing detection circuit or zero-crossing point determination. The transistor Q1's turn-on and turn-off speeds are fast; therefore, control is simple and fast, improving control accuracy and meeting the needs of applications with extremely high switching speed requirements.

[0085] The AC switching circuit and AC power supply provided by this utility model have been described in detail above. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

[0086] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. An alternating current switching circuit, characterized by, Comprise: Optocoupler, transistor, rectifier circuit, first resistor, second resistor, first capacitor, controller; The positive electrode of the optocoupler is connected with the control end of the controller, the negative electrode of the optocoupler is grounded, the collector of the optocoupler is connected with the power supply, the emitter of the optocoupler is connected with the first end of the first resistor and the control end of the transistor, the second end of the first resistor is grounded, the first end of the transistor is connected with the first end of the second resistor and the first output end of the rectifier circuit, the second end of the second resistor is connected with the first capacitor, the second end of the transistor is grounded and connected with the second end of the first capacitor and the second output end of the rectifier circuit, the first input end of the rectifier circuit is connected with the fire port of the alternating current power supply, the second input end of the rectifier circuit is connected with the second end of the load, and the first end of the load is connected with the zero line port of the alternating current power supply.

2. The alternating current switching circuit of claim 1, wherein, Also include: Power isolation circuit; The power isolation circuit comprises: isolation chip, second capacitor, third capacitor; The power input end of the isolation chip is connected with the power supply and the first end of the first capacitor, the ground end of the isolation chip is connected with the second end of the first capacitor and grounded, the positive output end of the isolation chip is connected with the first end of the second capacitor, and the 0V output end of the isolation chip is connected with the second end of the second capacitor; the positive output end of the isolation chip is connected with the collector of the optocoupler, and the 0V output end of the isolation chip is connected with the second end of the first resistor and the second end of the transistor.

3. The alternating current switching circuit of claim 1, wherein, Also include: Overvoltage protection circuit; The overvoltage protection circuit comprises: transient voltage suppression diode, protection resistor; The anode of the transient voltage suppression diode is connected with the first output end of the rectifier circuit, the cathode of the transient voltage suppression diode is connected with the second output end of the rectifier circuit, the first end of the protection resistor is connected with the cathode of the transient voltage suppression diode, and the second end of the protection resistor is grounded.

4. The alternating current switching circuit of claim 1, wherein, Also include: Temperature detection circuit; The temperature detection circuit comprises: thermistor, comparator; The first end of the thermistor is connected with the power supply, and the second end of the thermistor is connected with the comparator; The output end of the comparator is connected with the temperature detection end of the controller.

5. The AC switching circuit of claim 4, wherein, The temperature detection circuit further comprises an amplification circuit; The input end of the amplification circuit is connected with the second end of the thermistor, and the output end of the amplification circuit is connected with the input end of the comparator; The controller receives the electrical signal amplified by the amplification circuit to the resistance change of the thermistor.

6. The AC switching circuit of claim 1, wherein, Also include fault detection circuit; The fault detection circuit comprises current detection resistor and fault detection chip; The current detection resistor is connected in series between the second output end of the rectifier circuit and the ground end, the input end of the fault detection chip is connected with both ends of the current detection resistor, and the output end of the fault detection chip is connected with the fault detection end of the controller; The fault detection circuit monitors the circuit current in real time, and when the current is abnormal, the fault detection chip outputs a fault trigger signal to the controller.

7. The AC switching circuit of claim 1, wherein The rectifier circuit comprises a first diode, a second diode, a third diode, and a fourth diode. The first diode, the second diode, the third diode, and the fourth diode constitute a bridge circuit.

8. An alternating current power supply, characterised in that, An AC switching circuit comprising any one of claims 1 to 7.

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