Multi-path alternating current conversion circuit, power supply device and electronic equipment

Abstract

The utility model discloses a multipath AC conversion circuit, a power supply device and an electronic device. The circuit comprises an AC input end, an AC-AC conversion unit, an AC-AC voltage reduction unit and an AC-DC voltage reduction unit. The AC-AC conversion unit comprises a silicon controlled rectifier step-down circuit, a no-load follow current voltage stabilizing circuit and a first AC output end, the AC input end is connected with the input end of the silicon controlled rectifier step-down circuit and the input end of the no-load follow current voltage stabilizing circuit, and the output end of the silicon controlled rectifier step-down circuit and the output end of the no-load follow current voltage stabilizing circuit are connected with the output end of the first AC output end. And the no-load follow current voltage stabilizing circuit is used for keeping the voltage of the first AC output end stable through resistance-capacitance voltage reduction and voltage division under the no-load condition. According to the invention, various different power outputs can be provided, and the functions are rich; moreover, leakage protection equipment can be used normally, and the user experience is good.

Description

Technical Field

[0001] The utility model relates to the field of power supplies, in particular to a multi-channel AC conversion circuit, a power supply device and an electronic device. Background Art

[0002] With the development of industry and technology, a wide variety of electronic devices, such as electronic products and home appliances, continue to emerge. However, these various electronic products and appliances require different operating voltages and types. Therefore, AC conversion circuits have emerged. They can process AC power and generate AC or DC power of varying voltages to meet the requirements of different electronic devices. The shortcomings of existing AC conversion circuits are: 1. They can only provide a single AC or DC output, resulting in a single function; 2. Some AC conversion circuits use thyristor step-down circuits to achieve AC output. However, devices with leakage protection may not be able to use thyristor circuits, resulting in a poor user experience. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a multi-channel AC conversion circuit, power supply device, and electronic device that can provide a variety of different power outputs and rich functions, and the leakage protection device can be used normally, providing a good user experience.

[0004] According to an embodiment of the first aspect of the present utility model, a multi-channel AC conversion circuit includes: an AC input end for inputting AC power; an AC-AC conversion unit, the AC-AC conversion unit including a thyristor step-down circuit, a no-load freewheeling voltage-stabilizing circuit, and a first AC output end, the AC input end being respectively connected to the input end of the thyristor step-down circuit and the input end of the no-load freewheeling voltage-stabilizing circuit, the output end of the thyristor step-down circuit and the output end of the no-load freewheeling voltage-stabilizing circuit being respectively connected to the output end of the first AC output end, the no-load freewheeling voltage-stabilizing circuit being configured to maintain a stable voltage at the first AC output end through resistance-capacitance voltage reduction and voltage division under no-load conditions; an AC-AC step-down unit, the AC input end being connected to the input end of the AC-AC step-down unit, the AC-AC step-down unit being configured to step down the input AC power to obtain and output stepped-down AC power; and an AC-DC step-down unit, the AC input end being connected to the input end of the AC-DC step-down unit, the AC-DC step-down unit being configured to convert the input AC power into DC power and output the DC power.

[0005] According to some embodiments of the present invention, the AC-AC conversion unit further includes a constant temperature control circuit, which is connected to the control end of the thyristor step-down circuit to reduce the output power of the thyristor to keep the temperature constant when the temperature of the thyristor step-down circuit rises.

[0006] According to some embodiments of the present invention, the constant temperature control circuit includes a PTC resistor, and the PTC resistor is connected in series to the control end of the thyristor step-down circuit.

[0007] According to some embodiments of the present invention, the first AC output end includes a first neutral terminal, a second neutral terminal, a first live terminal and a second live terminal, the output end of the thyristor step-down circuit is connected to the first live terminal, the neutral terminal of the AC input end is connected to the first neutral terminal, the live output end of the no-load freewheeling voltage stabilization circuit is connected to the second live terminal, and the neutral output end of the no-load freewheeling voltage stabilization circuit is connected to the second neutral terminal.

[0008] According to some embodiments of the present utility model, the AC-AC step-down unit includes a first AC-DC step-down circuit, a current and voltage detection circuit, a constant current and voltage stabilization control unit, a DC-AC inverter circuit, and a second AC output end. The AC input end is connected to the input end of the first AC-DC step-down circuit, the output end of the first AC-DC step-down circuit is connected to the input end of the DC-AC inverter circuit through the current and voltage detection circuit, the output end of the DC-AC inverter circuit is connected to the second AC output end, the current and voltage detection circuit is connected to the constant current and voltage stabilization control unit for feedback of sampled current and voltage, and the output end of the constant current and voltage stabilization control unit is connected to the control end of the DC-AC inverter circuit for controlling the output of the DC-AC inverter circuit according to the sampled current and voltage.

[0009] According to some embodiments of the present invention, the AC-DC step-down unit includes a second AC-DC step-down circuit, a DC-DC step-down circuit, a first DC output end, and a second DC output end. The AC input end is connected to the input end of the second AC-DC step-down circuit, the output end of the second AC-DC step-down circuit is respectively connected to the input end and the second DC output end of the DC-DC step-down circuit, and the output end of the DC-DC step-down circuit is connected to the first DC output end.

[0010] The power supply device according to the second embodiment of the present invention includes the above-mentioned multi-channel AC conversion circuit.

[0011] An electronic device according to an embodiment of the third aspect of the present invention includes the above-mentioned power supply device.

[0012] The multi-channel AC conversion circuit, power supply device, and electronic device according to the embodiments of the present invention have at least the following beneficial effects:

[0013] In the embodiment of the present application, two AC outputs are provided through the AC-AC conversion unit and the AC-AC step-down unit, and one DC output is provided through the AC-DC step-down unit. This allows for a variety of different power outputs, rich functionality, and the ability to meet the requirements of various electronic devices. Furthermore, the AC-AC conversion unit is provided with a no-load freewheeling voltage-stabilizing circuit connected in parallel with the thyristor step-down circuit. Due to the involvement of the no-load freewheeling voltage-stabilizing circuit, the thyristors in the thyristor step-down circuit, under no-load operating conditions, use the resistance and capacitance of the no-load freewheeling voltage-stabilizing circuit to reduce and divide the voltage, allowing the voltage at the first AC output terminal to maintain a continuous and stable voltage waveform. This stable voltage waveform can smoothly pass through the leakage protection function without triggering the leakage protection function, allowing the device with leakage protection to be used normally, providing a good user experience.

[0014] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0016] Figure 1 This is a principle block diagram of a multi-channel AC conversion circuit in an embodiment of the present application;

[0017] Figure 2 This is a circuit diagram of an AC-AC conversion unit in an embodiment of the present application;

[0018] Figure 3 A circuit schematic diagram showing the connection between a thyristor step-down circuit and a device with leakage protection in the related art;

[0019] Figure 4 This is a circuit schematic diagram of the connection between the AC-AC conversion unit and the device with leakage protection in the embodiment of the present application;

[0020] Figure 5 This is a circuit diagram of the AC-AC step-down unit in an embodiment of the present application;

[0021] Figure 6 This is the interface diagram of the constant current and voltage stabilization control unit in the AC-AC step-down unit;

[0022] Figure 7 Schematic diagram of the circuit of the AC-DC step-down unit in the embodiment of the present application. DETAILED DESCRIPTION

[0023] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0024] In the description of the present invention, it should be understood that descriptions involving orientation, such as the orientation or positional relationship indicated by up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] In the description of this utility model, "a plurality" means more than two. The use of "first" or "second" is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0026] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0027] The present application aims to solve the problems of single function and poor user experience of AC conversion circuits. The following first introduces some background of this application. With the development of industry and technology, various electronic products, home appliances and other electronic devices continue to emerge. However, the working voltages and types required by various electronic products and home appliances are different. Therefore, AC conversion circuits came into being. They can process AC power and generate AC or DC power with different voltage values ​​to meet the requirements of different electronic devices. The shortcomings of existing AC conversion circuits are: 1. They can only provide a single AC or DC output and have a single function; 2. Some AC conversion circuits use thyristor step-down circuits to achieve AC output. However, devices with leakage protection cannot be used in thyristor circuits, resulting in poor user experience.

[0028] Regarding the second point that the device with leakage protection cannot be used in the thyristor circuit, it is because there are certain capacitive devices in the circuit of the leakage protection plug. The capacitive devices will cause the thyristor circuit to not work properly under no-load conditions, such as the thyristor is not controlled, the output voltage increases abnormally, the output waveform is abnormal, etc. Since the thyristor circuit cannot work properly under no-load conditions, when the opening state of the thyristor in the positive and negative half-cycles (such as: opening time, opening angle) cannot be completely symmetrical or consistent, the energy of the positive and negative half-cycles cannot be completely offset. After the device with leakage protection is connected, the leakage protection device in the leakage protector detects and amplifies the residual energy of the positive and negative half-cycles, and detects the residual energy through the internal circuit. If the residual energy is too large, it is determined that the device has leakage, and the leakage protection is activated, making the device unusable.

[0029] In order to solve the above problems, the present application proposes a multi-channel AC conversion circuit, a power supply device and an electronic device. The multi-channel AC conversion circuit of the present application is first introduced below. Figure 1 As shown, a multi-channel AC conversion circuit includes: an AC input terminal, an AC-AC conversion unit, an AC-AC step-down unit, and an AC-DC step-down unit. The AC input terminal is used to input AC power, such as 220V mains power.

[0030] In this embodiment, the AC-AC conversion unit includes a thyristor step-down circuit, a no-load freewheeling voltage-stabilizing circuit, and a first AC output terminal. The AC input terminal is respectively connected to the input terminal of the thyristor step-down circuit and the input terminal of the no-load freewheeling voltage-stabilizing circuit. The output terminal of the thyristor step-down circuit and the output terminal of the no-load freewheeling voltage-stabilizing circuit are respectively connected to the output terminal of the first AC output terminal. The no-load freewheeling voltage-stabilizing circuit is used to maintain a stable voltage at the first AC output terminal through resistance-capacitance voltage reduction and voltage division under no-load conditions. The AC input terminal is connected to the input terminal of the AC-AC step-down unit, which is used to step down the input AC power to obtain and output the stepped-down AC power. The AC input terminal is also connected to the input terminal of the AC-DC step-down unit, which is used to convert the input AC power into DC power and output it.

[0031] In the embodiment of the present application, two AC outputs are provided through the AC-AC conversion unit and the AC-AC step-down unit, and one DC output is provided through the AC-DC step-down unit. This allows for a variety of different power outputs, rich functionality, and the ability to meet the requirements of various electronic devices. Furthermore, the AC-AC conversion unit is provided with a no-load freewheeling voltage-stabilizing circuit connected in parallel with the thyristor step-down circuit. Due to the involvement of the no-load freewheeling voltage-stabilizing circuit, the thyristors in the thyristor step-down circuit, under no-load operating conditions, use the resistance and capacitance of the no-load freewheeling voltage-stabilizing circuit to reduce and divide the voltage, allowing the voltage at the first AC output terminal to maintain a continuous and stable voltage waveform. This stable voltage waveform can smoothly pass through the leakage protection function without triggering the leakage protection function, allowing the device with leakage protection to be used normally, providing a good user experience.

[0032] refer to Figure 2 As shown, in the embodiment of the present application, the thyristor step-down circuit includes a thyristor Q11, a capacitor CBB2, a capacitor CBB3, a resistor R92, a resistor R94, an adjustable resistor RW1 and a bidirectional trigger diode TV1. JP1 is an interface for the AC input end. The live wire terminal L of the interface JP1 is connected to the input end of the thyristor Q11 through a fuse F3. The output end of the thyristor Q11 is connected to the live wire terminal of the first AC output end. The neutral wire terminal N of the interface JP1 is connected to the neutral wire terminal of the first AC output end. The gate of the thyristor Q11 is connected to one end of the bidirectional trigger diode TV1. The other end of the bidirectional trigger diode TV1 is respectively connected to the other end of the capacitor CBB2 and one end of the resistor R92. The input end of the thyristor Q11 is respectively connected to one end of the capacitor CBB2 and one end of the capacitor CBB3. The other end of the resistor R92 is connected to the other end of the capacitor CBB3. The other end of the capacitor CBB3 is connected to the output end of the thyristor Q11 through the resistor R94 and the adjustable resistor RW1 connected in series.

[0033] The no-load freewheeling voltage stabilization circuit includes a resistor RT3, a resistor R139, a resistor R137, a resistor RT6, a resistor R136, a resistor R133, a capacitor CBB4, and a capacitor CBB5. Resistors RT3 and RT6 are PTC (Positive Temperature Coefficient) resistors. The input end of the thyristor Q11 is connected to the live wire terminal of the first AC output terminal via the resistors RT3, R139, R137, and RT6 connected in series. The common end of the resistors RT3 and R139 is connected to one end of the capacitor CBB4. The other end of the capacitor CBB4 is connected to the neutral wire terminal of the first AC output terminal via the resistors R136 and R133 connected in series. The other end of the capacitor CBB4 is also connected to the common end of the resistors R139 and R137. Capacitor CBB5 is connected in parallel with the resistor R133.

[0034] The working principles of the thyristor step-down circuit and the no-load freewheeling voltage stabilization circuit in the embodiment of the present application are as follows:

[0035] The purpose of the no-load freewheeling voltage stabilization circuit in this application is to enable the thyristor step-down circuit to achieve continuous and stable voltage at the output end under no-load conditions. The thyristor step-down circuit controls the conduction time of the thyristor to achieve delayed opening of the input AC voltage every half cycle (in the form of chopping) and ultimately complete the control of the output load power.

[0036] refer to Figure 3 As shown, when there is no no-load freewheeling voltage stabilization circuit, only a thyristor step-down circuit is provided. A user device with a leakage protection plug is connected to the first AC output terminal, and the switch S1 is in the closed state. At this time, only the leakage protection plug is connected to the thyristor step-down circuit at the user device end. However, the load in the leakage protection plug is very small and the current consumed is also very small. According to the characteristics of the thyristor, the thyristor Q11 requires a certain working current to continue to conduct after normal conduction. Since the working current of the leakage protection plug is too small to maintain the normal conduction of the thyristor Q11, the thyristor Q11 will be cut off prematurely. At this time, the conduction time of the thyristor Q11 in the positive and negative half-cycles of the AC power will be inconsistent. Similarly, the energy of the positive and negative half-cycles cannot be offset, and residual energy is bound to exist. When the residual energy passes through the leakage protection plug, it will be amplified by the leakage detection circuit and control the release to shut down the output through the drive circuit to start the leakage protection, causing the equipment to be unusable.

[0037] refer to Figure 4 As shown, because the operating current of the leakage protection plug is too low to maintain normal conduction of the thyristor, the thyristor will be prematurely turned off. However, when the no-load freewheeling voltage regulator circuit is connected, the operating current of the leakage protection plug is provided by the series circuit of resistors RT3, R139, R137, and RT6. The current is continuous in the positive and negative half-cycles, eliminating the problem of current inconsistency between the positive and negative half-cycles. This prevents the leakage protection from activating and causing the device to become unusable. By using resistor R136 / capacitor CBB5 in series with resistor RT3 / resistor R139 for voltage division, and selecting appropriate component parameters, the output voltage stability of the first AC output terminal can be ensured.

[0038] According to some embodiments of the present application, reference Figure 1 As shown, the AC-AC conversion unit in the embodiment of the present application also includes a constant temperature control circuit, which is connected to the control end of the thyristor step-down circuit to reduce the output power of the thyristor to keep the temperature constant when the temperature of the thyristor step-down circuit rises.

[0039] In this embodiment, the constant temperature control circuit is used to maintain the constant temperature of the thyristor step-down circuit, thereby reducing the risk of damage to the thyristor due to overheating.

[0040] It should be noted that the constant temperature control circuit can detect the temperature of the thyristor step-down circuit through a temperature sensor, and then connect the control end of the thyristor Q11 through an MCU or other control module. When the MCU detects that the temperature is too high, it controls the thyristor Q11 to reduce the conduction time, thereby achieving constant temperature control.

[0041] According to some embodiments of the present application, the constant temperature control circuit includes a PTC resistor RT5, which is connected in series to the control end of the thyristor step-down circuit.

[0042] In this embodiment, constant temperature control of the thyristor step-down circuit can be achieved by connecting a PTC resistor in series to the circuit of the control end of the thyristor step-down circuit, which can save costs.

[0043] refer to Figure 2 As shown, in the embodiment of the present application, the PTC resistor RT5 is connected in series between the adjustable resistor RW1 and the output end of the thyristor Q11, and the PTC resistor RT5 is close to the thyristor Q11. The working principle of the constant temperature control circuit is as follows:

[0044] The adjustable resistor RW1 and the resistor R94 are both current limiting resistors, wherein the adjustable resistor RW1 is used to adjust the series current size to ensure the consistency of the product output voltage; the capacitor CBB3 is an energy storage capacitor; the resistor R92 and the capacitor CBB2 form an RC filter circuit. In this application, the high voltage input AC power (for example, 220V AC power) is stepped down to a low voltage output AC power (for example, 110V AC power) by controlling the conduction time of the thyristor Q11; in the AC circuit, the thyristor Q11 is turned on once in each half cycle; wherein the normal conduction time of the thyristor Q11 per half cycle depends on the series current limiting size of the adjustable resistor RW1 and the resistor R94 and the capacitor charging time and voltage of the capacitor CBB3. When the voltage on the capacitor CBB3 reaches the trigger channel condition of the bidirectional trigger diode TV1, the thyristor Q11 is turned on through the filtering of the resistor R92 and the capacitor CBB2 and the bidirectional trigger diode TV1. Due to the adjustable resistor RW1, the resistor R94, the capacitor CBB3, the resistor R92, the capacitor CBB2 and The bidirectional trigger diode TV1 is a fixed-parameter device. The thyristor's on-time is primarily limited by the series resistance of the RT5 device or the current. Because the PTC resistor RT5 is in close proximity to the thyristor Q11, when the temperature of the thyristor Q11 continues to rise under prolonged or high-load conditions, the temperature rise is transmitted to the PTC resistor RT5. Since the PTC resistor RT5 is a positive temperature device, the temperature rise and internal resistance of the PTC resistor RT5 also increase, which in turn increases the series resistance in the thyristor Q11 conduction circuit, reducing the series current. This prolongs the charging time of the capacitor CBB3, shortening the on-time of the thyristor Q11 and shortening the operating time of the load connected to the output terminal of the thyristor Q11 per unit time, thereby reducing power consumption.

[0045] According to some embodiments of the present application, the first AC output end includes a first neutral terminal JP6, a second neutral terminal JP8, a first live terminal JP12 and a second live terminal JP9, the output end of the thyristor Q11 is connected to the first live terminal JP12, the neutral terminal N of the AC input end is connected to the first neutral terminal JP6, the live output end of the no-load freewheeling voltage stabilization circuit, that is, the resistor RT6 is connected to the second live terminal JP9, and the neutral output end of the no-load freewheeling voltage stabilization circuit, that is, the resistor R133 is connected to the second neutral terminal JP8.

[0046] In this embodiment, since the no-load freewheeling voltage-stabilizing circuit has a certain power loss when operating, the embodiment of the present application divides the neutral line into two contact terminals. When a load is connected to the neutral line, it will simultaneously connect to the first neutral line terminal JP6 and the second neutral line terminal JP8 and conduct. At this time, the no-load freewheeling voltage-stabilizing circuit can operate normally. When the load is removed, the first neutral line terminal JP6 and the second neutral line terminal JP8 are disconnected and not conducting. At this time, the no-load freewheeling voltage-stabilizing circuit stops operating, thereby reducing circuit loss. The same applies to the live wire terminals of the first live wire terminal JP12 and the second live wire terminal JP9. Therefore, the present application divides the neutral wire terminal and the live wire terminal of the first AC output terminal into two terminals, forming a non-insertion low-power device. When no device is connected, the no-load freewheeling voltage-stabilizing circuit is not connected to the circuit and there is no loss. This can effectively reduce no-load power consumption.

[0047] According to some embodiments of the present application, the AC-AC step-down unit includes a first AC-DC step-down circuit, a current and voltage detection circuit, a constant current and voltage stabilization control unit, a DC-AC inverter circuit, and a second AC output end. The AC input end is connected to the input end of the first AC-DC step-down circuit, the output end of the first AC-DC step-down circuit is connected to the input end of the DC-AC inverter circuit through the current and voltage detection circuit, the output end of the DC-AC inverter circuit is connected to the second AC output end, the current and voltage detection circuit is connected to the constant current and voltage stabilization control unit for feedback of the sampled current and voltage, and the output end of the constant current and voltage stabilization control unit is connected to the control end of the DC-AC inverter circuit for controlling the output of the DC-AC inverter circuit according to the sampled current and voltage.

[0048] refer to Figure 5 and Figure 6As shown, the current and voltage detection circuit in the embodiment of the present application includes a first voltage sampling circuit composed of resistors R53 and R58 connected in series, a second voltage sampling circuit composed of resistors R37 and R40 connected in series, and a current sampling circuit composed of resistor R8. The DC-AC inverter circuit is composed of four switching tubes M2-M5, a switching tube M1 is provided in the first AC-DC step-down circuit, the constant current and voltage stabilization control unit adopts an MCU, JP2 is the interface of the MCU, the common end of the resistors R53 and R58 is connected to the pin FB2 of the MCU, the common end of the resistors R37 and R40 is connected to the pin FB1 of the MCU, the output end of the resistor R8 is connected to the pin CS of the MCU, the pin OUT of the MCU is connected to the control end of the switching tube M1, and the pins PWM1-PWM4 of the MCU are respectively connected to the control ends of the switching tubes M2-M5. The MCU calculates the control signal that can stabilize the on / off of the switch tube M1 in the first AC-DC buck circuit through internal calculations using the voltage of the first voltage sampling circuit. The control signal is then filtered through the diode D1 for freewheeling and the inductor L2 and capacitor CE2 in series to achieve a stable voltage output. At the same time, the MCU calculates the control signal that stabilizes the complementary conduction of the switch tubes M2 / M5 and the switch tubes M3 / M4 in the DC-AC inverter circuit through the second voltage sampling circuit and the current sampling circuit, thereby stabilizing the current and voltage at the AC output end.

[0049] In this embodiment, the constant current and voltage stabilization control unit obtains voltage and current signals through the current and voltage detection circuit and controls the switches M1-M5, thereby stabilizing the current and voltage at the AC output end.

[0050] It should be noted that, in addition to the above methods, only the first AC-DC buck circuit, the DC-AC inverter circuit and the second AC output end can also be used to achieve the AC buck output of the AC-AC buck unit.

[0051] According to some embodiments of the present application, reference Figure 7 As shown, the AC-DC step-down unit includes a second AC-DC step-down circuit, a DC-DC step-down circuit, a first DC output terminal and a second DC output terminal. The AC input terminal is connected to the input terminal of the second AC-DC step-down circuit, the output terminal of the second AC-DC step-down circuit is respectively connected to the input terminal and the second DC output terminal of the DC-DC step-down circuit, and the output terminal of the DC-DC step-down circuit is connected to the first DC output terminal.

[0052] In this embodiment, two-way DC output is achieved through the second AC-DC buck circuit and the DC-DC buck circuit, respectively, which can enrich the function of the power output.

[0053] It should be noted that, in addition to the above methods, only one DC output or multiple DC-DC modules can be used to achieve more DC outputs.

[0054] The present application also relates to a power supply device, comprising the multi-channel AC conversion circuit of the above embodiment.

[0055] The present application also relates to an electronic device, comprising the power supply device of the above embodiment.

[0056] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A multi-channel AC conversion circuit, characterized in that: include: AC input terminal, used to input alternating current; an AC-AC conversion unit, the AC-AC conversion unit comprising a thyristor step-down circuit, a no-load freewheeling voltage stabilization circuit, and a first AC output terminal, the AC input terminal being connected to the input terminal of the thyristor step-down circuit and the input terminal of the no-load freewheeling voltage stabilization circuit, respectively; the output terminal of the thyristor step-down circuit and the output terminal of the no-load freewheeling voltage stabilization circuit being connected to the output terminal of the first AC output terminal, respectively; the no-load freewheeling voltage stabilization circuit being configured to maintain a stable voltage at the first AC output terminal by means of resistance-capacitance voltage reduction and voltage division under no-load conditions; an AC-AC step-down unit, wherein the AC input end is connected to the input end of the AC-AC step-down unit, and the AC-AC step-down unit is used to step down the input alternating current to obtain stepped-down alternating current and output the stepped-down alternating current; The AC-DC step-down unit has the AC input end connected to the input end of the AC-DC step-down unit, and the AC-DC step-down unit is used to convert the input end alternating current into direct current and output it.

2. The multi-channel AC conversion circuit according to claim 1, characterized in that: The AC-AC conversion unit further includes a constant temperature control circuit connected to the control terminal of the thyristor step-down circuit for reducing the output power of the thyristor to keep the temperature constant when the temperature of the thyristor step-down circuit rises.

3. The multi-channel AC conversion circuit according to claim 2, characterized in that: The constant temperature control circuit includes a PTC resistor, which is connected in series to the control end of the thyristor step-down circuit.

4. The multi-channel AC conversion circuit according to claim 1, characterized in that: The first AC output end includes a first neutral terminal, a second neutral terminal, a first live terminal, and a second live terminal. The output end of the thyristor step-down circuit is connected to the first live terminal, the neutral terminal of the AC input end is connected to the first neutral terminal, the live output end of the no-load freewheeling voltage stabilization circuit is connected to the second live terminal, and the neutral output end of the no-load freewheeling voltage stabilization circuit is connected to the second neutral terminal.

5. The multi-channel AC conversion circuit according to claim 1, characterized in that: The AC-AC step-down unit includes a first AC-DC step-down circuit, a current and voltage detection circuit, a constant current and voltage stabilization control unit, a DC-AC inverter circuit, and a second AC output end. The AC input end is connected to the input end of the first AC-DC step-down circuit, the output end of the first AC-DC step-down circuit is connected to the input end of the DC-AC inverter circuit through the current and voltage detection circuit, and the output end of the DC-AC inverter circuit is connected to the second AC output end. The current and voltage detection circuit is connected to the constant current and voltage stabilization control unit for feedback of sampled current and voltage, and the output end of the constant current and voltage stabilization control unit is connected to the control end of the DC-AC inverter circuit for controlling the output of the DC-AC inverter circuit according to the sampled current and voltage.

6. The multi-channel AC conversion circuit according to claim 1, characterized in that: The AC-DC step-down unit includes a second AC-DC step-down circuit, a DC-DC step-down circuit, a first DC output end, and a second DC output end. The AC input end is connected to the input end of the second AC-DC step-down circuit, the output end of the second AC-DC step-down circuit is respectively connected to the input end and the second DC output end of the DC-DC step-down circuit, and the output end of the DC-DC step-down circuit is connected to the first DC output end.

7. A power supply device, characterized in that: The multi-channel AC conversion circuit comprises the multi-channel AC conversion circuit according to any one of claims 1 to 6.

8. An electronic device, characterized in that: Includes the power supply device according to claim 7.

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