Power-off control circuit and frequency conversion equipment

Abstract

The utility model relates to a power-off control circuit and frequency conversion equipment. The input end of a rectifier module in the circuit is connected with an input power supply; the power output module is connected with the output end of the rectifier module and is used for supplying power to a load; the output end of the switching power supply module is connected with auxiliary equipment; the first end of the power taking module is connected between the output end of the rectification module and the power supply output module, and the second end of the power taking module is connected with the input end of the switching power supply module; the power taking module is configured in a way that the input power supply is switched off, the electric quantity is consumed, the voltage is reduced, and then the switching power supply is switched off, so that the output end of the switching power supply is quickly powered off; the electric quantity of a small-capacity energy storage capacitor on the power taking module can be quickly exhausted after the input power supply is switched off; the output voltage of the switching power supply module is insufficient, so that the auxiliary equipment is automatically and quickly closed, misoperation of a user is avoided, and the product reliability is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply, in particular to a power-off control circuit and a variable frequency device. BACKGROUND

[0002] The variable frequency controller is an electronic control device, which is mainly used for realizing variable frequency control of an AC motor, adjusting motor speed by adjusting power supply frequency and voltage, and is widely applied to industrial production, mechanical equipment, air conditioners, elevators and other fields.

[0003] At present, in the existing variable frequency controller products (such as variable frequency mobile air conditioners or variable frequency dehumidifiers), the switching power supply module usually takes power from the large-capacity high-voltage electrolytic capacitor of the power output end, which can easily cause the switching power supply module to continue to work for a long time after the input power is disconnected, and the product shows the same state as when the input power is connected, for example, the display screen continues to display or some functions can be triggered by pressing the keys, which can easily cause user misoperation and reduce the reliability of the product. CONTENT OF THE UTILITY MODEL

[0004] Therefore, it is necessary to provide a power-off control circuit and a variable frequency device which can quickly cut off the output end of the switching power supply when the input power is disconnected, avoid user misoperation and improve the reliability of the product.

[0005] In a first aspect, the present application provides a power-off control circuit, comprising:

[0006] a rectifier module, an input end of the rectifier module being used for connecting an input power;

[0007] a power output module, the power output module being connected to an output end of the rectifier module, and the power output module being used for supplying power to a load;

[0008] a switching power supply module, an output end of the switching power supply module being used for connecting an auxiliary device;

[0009] a power taking module, a first end of the power taking module being connected between the output end of the rectifier module and the power output module, and a second end of the power taking module being connected to an input end of the switching power supply module; the power taking module is configured to be disconnected from the input power, the electric quantity is consumed, the voltage is reduced, and the switching power supply is turned off.

[0010] In one of the embodiments, the rectifier module comprises a rectifier device; the power output module comprises a PFC circuit, a first resistor and a first capacitor;

[0011] a first end of the first resistor is connected to a first output pin of the rectifier device, a second end of the first resistor is connected to a negative electrode of the first capacitor, and a positive electrode of the first capacitor is connected to the load;

[0012] The PFC circuit is connected with the positive pole and the negative pole of the first capacitor respectively, and the PFC circuit is connected with the second output pin of the rectifier device; the first end of the power taking module is connected between the second output pin of the rectifier device and the PFC circuit.

[0013] In one of the embodiments, the PFC circuit comprises a first switch tube, a first inductor, a first diode and a second resistor;

[0014] The first end of the first inductor is connected with the first end of the power taking module and the second output pin of the rectifier device respectively, the second end of the first inductor is connected with the drain of the first switch tube and the anode of the first diode respectively, and the cathode of the first diode is connected with the positive pole of the first capacitor;

[0015] The source of the first switch tube is connected with the negative pole of the first capacitor, and the gate of the first switch tube is used for connecting the control chip; the first end of the second resistor is connected with the gate of the first switch tube, and the second end of the second resistor is connected with the source of the first switch tube.

[0016] In one of the embodiments, the PFC circuit comprises a second diode and a second capacitor;

[0017] The anode of the second diode is connected between the rectifier device and the first end of the first inductor, the cathode of the second diode is connected with the positive pole of the second capacitor, the negative pole of the second capacitor is connected with the negative pole of the first capacitor, and the input end of the switching power supply module is connected between the cathode of the second diode and the positive pole of the second capacitor.

[0018] In one of the embodiments, the capacitance of the second capacitor is smaller than the capacitance of the first capacitor.

[0019] In one of the embodiments, the power output module further comprises a third capacitor and a third resistor;

[0020] The first end of the third capacitor is connected with the first output pin of the rectifier device, the second end of the third capacitor is connected with the second output pin of the rectifier device; the first end of the third resistor is connected with the first end of the third capacitor, and the second end of the third resistor is connected with the second end of the third capacitor.

[0021] In one of the embodiments, the power-off control circuit further comprises a power-on surge protection module; the power-on surge protection module is connected with the input end of the rectifier module, and the power-on surge protection module is used for connecting the control chip.

[0022] In one of the embodiments, the switching power supply module comprises a voltage transformation module, a first voltage conversion module and a second voltage conversion module; the auxiliary device comprises a first auxiliary operation module and a second auxiliary operation module;

[0023] The voltage conversion module is connected with the power supply output module, and the voltage conversion module is connected with the power supply output module.

[0024] In one embodiment, the first auxiliary operation module includes an inverter circuit control module, and the inverter circuit control module is used for controlling the load; the second auxiliary operation module includes a display key module.

[0025] The inverter circuit control module is connected with the first voltage conversion module and the power supply output module, and the display key module is connected with the second voltage conversion module.

[0026] In a second aspect, the application provides a frequency conversion device, which comprises the power-off control circuit according to any one of the above.

[0027] One of the above technical solutions has the following advantages and beneficial effects:

[0028] In the power-off control circuit, the rectifier module, the power supply output module, the switching power supply module and the power taking module are included; the input end of the rectifier module is used for connecting the input power supply; the power supply output module is connected with the output end of the rectifier module, and the power supply output module is used for supplying power to the load; the output end of the switching power supply module is used for connecting the auxiliary device; the first end of the power taking module is connected between the output end of the rectifier module and the power supply output module, and the second end of the power taking module is connected with the input end of the switching power supply module; the power taking module is configured to disconnect the input power supply, consume the electric quantity, reduce the voltage and then shut down the switching power supply, so as to realize the rapid power-off of the output end of the switching power supply. According to the application, the power taking module is arranged between the output end of the rectifier module and the power supply output module, and the power taking module is connected with the switching power supply module, so that the power taking module obtains the electric signal from the output end of the rectifier module, and the switching power supply module takes power from the power taking module. Therefore, after the input power supply is disconnected, the electric quantity on the power taking module can be quickly consumed, the output voltage of the switching power supply module is insufficient, and the auxiliary device is automatically and quickly shut down, so as to avoid user misoperation and improve product reliability. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a first structural schematic diagram of the power-off control circuit in one embodiment.

[0030] Figure 2 It is a second structural schematic diagram of the power-off control circuit in one embodiment.

[0031] Figure 3 It is a third structural schematic diagram of the power-off control circuit in one embodiment.

[0032] Figure 4 It is a circuit schematic diagram of the power-off control circuit in one embodiment.

[0033] Reference signs:

[0034] 10, rectifier module; 110, rectifier device; 120, power-on surge protection module; 20, power output module; 210, PFC circuit; 30, switching power supply module; 310, voltage conversion module; 320, first voltage conversion module; 330, second voltage conversion module; 40, power taking module; 50, control chip; 60, load; 70, auxiliary device; 710, first auxiliary operation module; 720, second auxiliary operation module;

[0035] Q1, first switch tube; L1, first inductor; D1, first diode; D2, second diode; R1, first resistor; R2, second resistor; R3, third resistor; C1, first capacitor; C2, second capacitor; C3, third capacitor. DETAILED DESCRIPTION

[0036] In order to make the personnel in the art better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person of ordinary skill in the art without making creative labor should belong to the protection scope of the present application.

[0037] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units does not necessarily limit to those clearly listed steps or units, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0038] In addition, the meaning of the term "a plurality of" should be two and more than two.

[0039] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0040] In one embodiment, as Figure 1As shown, a power-off control circuit is provided, which includes a rectifier module 10, a power output module 20, a switching power supply module 30 and a power taking module 40. The input end of the rectifier module 10 is used to connect an input power supply; the output end of the rectifier module 10 is connected to the power output module 20, and the power output module 20 is used to supply power to a load 60; the output end of the switching power supply module 30 is used to connect an auxiliary device 70; the first end of the power taking module 40 is connected between the output end of the rectifier module 10 and the power output module 20, and the second end of the power taking module 40 is connected to the input end of the switching power supply module 30; the power taking module 40 is configured to be disconnected from the input power supply, the power is consumed, the voltage is reduced, and the switching power supply is turned off.

[0041] The power-off control circuit can be applied to a variable frequency controller product, for example, the power-off control circuit can be applied to a variable frequency mobile air conditioner or a variable frequency dehumidifier, i.e., the load 60 can be a main machine in a variable frequency mobile air conditioner or a main machine in a variable frequency dehumidifier. The input power supply can be an alternating current power supply with a working voltage of 220V or 110V. The auxiliary device 70 can be an interactive operation device, for example, the auxiliary device 70 can be a display and / or a key module.

[0042] The rectifier module 10 can be used to rectify the alternating current signal transmitted by the input power supply, and then output the rectified signal. For example, the rectifier module 10 can be but is not limited to a bridge rectifier module 10. Based on the connection of the rectifier module 10 to the power output module 20, the rectifier module 10 can transmit the rectified signal to the power output module 20; the power output module 20 can be used to store the rectified signal transmitted by the rectifier module 10, and then supply power to the load 60.

[0043] The power taking module 40 is used to take power from the output end of the rectifier module 10, and store the obtained power to supply power to the switching power supply module 30. The switching power supply module 30 is used to supply power to the auxiliary device 70, and the switching power supply module 30 is also used to convert the received signal, and then transmit the signal meeting the power supply requirement to the auxiliary device 70. For example, the switching power supply module 30 can be used to convert the received signal into a 15V and / or 12V signal; the switching power supply module 30 can also convert the 15V and / or 12V signal into a 5V and / or 3.3V signal.

[0044] The electrical signal storage capacity of the power-taking module 40 is smaller than that of the power output module 20. By connecting the first end of the power-taking module 40 between the output end of the rectifier module 10 and the power output module 20, an additional electrical signal output is added between the output end of the rectifier module 10 and the power output module 20. The output electrical signal passes through the power-taking module 40. When the input power is normally on, the switching power supply module 30 draws power from the power-taking module 40 to supply power to the auxiliary device 70. When the input power is disconnected, the electrical energy stored in the power-taking module 40 is quickly depleted, and the electrical signal obtained by the switching power supply module 30 will automatically shut down due to insufficient voltage. This achieves the goal of quickly cutting off power to the auxiliary device 70 after the input power is disconnected, thus preventing accidental operation of the auxiliary device 70 by the user.

[0045] In the above embodiment, the input terminal of the rectifier module 10 is connected to the input power supply; the power output module 20 is connected to the output terminal of the rectifier module 10 and is used to supply power to the load 60; the output terminal of the switching power supply module 30 is used to connect to the auxiliary equipment 70; the first terminal of the power extraction module 40 is connected between the output terminal of the rectifier module 10 and the power output module 20, and the second terminal of the power extraction module 40 is connected to the input terminal of the switching power supply module 30; the power extraction module 40 is configured such that the input power supply is disconnected, the power is consumed, the voltage drops and the switching power supply is turned off, thereby realizing the rapid power cut-off of the output terminal of the switching power supply. This application sets up a power-taking module 40 between the output terminal of the rectifier module 10 and the power output module 20, and connects the power-taking module 40 to the switching power supply module 30. This allows the power-taking module 40 to obtain an electrical signal from the output terminal of the rectifier module 10, and the switching power supply module 30 to draw power from the power-taking module 40. As a result, when the input power is disconnected, the power on the power-taking module 40 can be quickly depleted, and the output voltage of the switching power supply module 30 is insufficient, causing the auxiliary equipment 70 to automatically and quickly shut down, avoiding user misoperation and improving product reliability.

[0046] In one embodiment, such as Figure 2 As shown, the rectifier module 10 includes a rectifier device 110; the power output module 20 includes a PFC circuit 210, a first resistor R1, and a first capacitor C1; the first end of the first resistor R1 is connected to the first output pin of the rectifier device 110, the second end of the first resistor R1 is connected to the negative terminal of the first capacitor C1, and the positive terminal of the first capacitor C1 is connected to the load 60; the PFC circuit 210 is connected to the positive and negative terminals of the first capacitor C1 respectively, and the PFC circuit 210 is connected to the second output pin of the rectifier device 110; the first end of the power extraction module 40 is connected between the second output pin of the rectifier device 110 and the PFC circuit 210.

[0047] The rectifier 110 can be a full-bridge rectifier 110. For example, the rectifier 110 may have a first input pin, a second input pin, a first output pin, and a second output pin. The PFC circuit 210 can be used to improve the power factor and EMI performance of the circuit. The first capacitor C1 can be a large-capacity high-voltage electrolytic capacitor, and the first resistor R1 is a current sampling resistor. By sampling the voltage across the first resistor R1, the current flowing through the first resistor R1 is calculated, protecting the PFC circuit 210 and the rectifier 110 from damage due to excessive current.

[0048] When the input power is turned on, the rectifier 110 rectifies the AC signal transmitted by the input power, and the PFC circuit 210 adjusts the power factor of the rectified signal output by the rectifier 110. Then, the power-adjusted signal is transmitted to the load 60 through the first resistor R1 and the first capacitor C1 to achieve stable power supply to the load 60.

[0049] In one embodiment, such as Figure 4 As shown, the PFC circuit 210 includes a first switching transistor Q1, a first inductor L1, a first diode D1, and a second resistor R2. The first end of the first inductor L1 is connected to the first end of the power extraction module 40 and the second output pin of the rectifier device 110, respectively. The second end of the first inductor L1 is connected to the drain of the first switching transistor Q1 and the anode of the first diode D1, respectively. The cathode of the first diode D1 is connected to the positive terminal of the first capacitor C1. The source of the first switching transistor Q1 is connected to the negative terminal of the first capacitor C1, and the gate of the first switching transistor Q1 is used to connect to the control chip 50. The first end of the second resistor R2 is connected to the gate of the first switching transistor Q1, and the second end of the second resistor R2 is connected to the source of the first switching transistor Q1.

[0050] In this design, the first diode D1 can be a fast recovery diode. The first switching transistor Q1 can be a MOSFET or an IGBT. The control chip 50 can be a driver chip or an MCU. The control chip 50 is used to drive the switching of the first switching transistor Q1.

[0051] When the input power is turned on, the rectifier 110 rectifies the AC signal transmitted by the input power. By controlling the on / off state of the first switch Q1 in the PFC circuit 210, the rectified signal output by the rectifier 110 is adjusted for power factor. The power-adjusted signal is then transmitted to the load 60 through the first capacitor C1, thus achieving a stable power supply to the load 60. In addition, the power-taking module 40 obtains the rectified signal output by the rectifier 110, and the switching power supply module 30 draws power from the power-taking module 40 to achieve a stable power supply to the auxiliary equipment 70.

[0052] Based on the reverse cutoff effect of the first diode D1 in the PFC circuit 210, the first capacitor C1 cannot supply power to the switching power supply module 30. When the input power is disconnected, the electrical energy stored in the power extraction module 40 will be quickly depleted. Consequently, the electrical signal obtained by the switching power supply module 30 will be automatically shut down due to insufficient voltage, causing the switching power supply module 30 to stop working. This achieves the goal of quickly cutting off power to the auxiliary device 70 after the input power is disconnected, thereby preventing users from accidentally operating the auxiliary device 70.

[0053] In one embodiment, such as Figure 4 As shown, the power supply module 40 includes a second diode D2 and a second capacitor C2; the anode of the second diode D2 is connected between the rectifier 110 and the first terminal of the first inductor L1, the cathode of the second diode D2 is connected to the positive terminal of the second capacitor C2, the negative terminal of the second capacitor C2 is connected to the negative terminal of the first capacitor C1, and the input terminal of the switching power supply module 30 is connected between the cathode of the second diode D2 and the positive terminal of the second capacitor C2.

[0054] The second diode D2 can be a rectifier diode; the second diode D2 serves as a reverse cutoff, preventing the second capacitor C2 from supplying power to the PFC circuit 210 when the voltage at the second terminal of the rectifier device 110 is lower than the positive voltage of the second capacitor C2. The second capacitor C2 can be a small-capacity high-voltage electrolytic capacitor.

[0055] For example, the capacitance of the second capacitor C2 is smaller than that of the first capacitor C1. By adding an electrical signal output between the output of the rectifier module 10 and the power output module 20, the electrical signal output by the rectifier device 110 passes through the second diode D2 and reaches the second capacitor C2, and the switching power supply module 30 draws power from the second capacitor C2. When the input power is on, the switching power supply module 30 draws power normally from the second capacitor C2 and supplies power to the auxiliary device 70 normally; when the input power is off, the energy stored in the second capacitor C2 is quickly depleted, and the electrical signal obtained by the switching power supply module 30 will automatically shut down due to insufficient voltage, thereby quickly cutting off power to the auxiliary device 70 after the input power is disconnected, achieving the purpose of quickly shutting down the auxiliary device 70, thus avoiding user misoperation of the auxiliary device 70 and improving product reliability.

[0056] In one embodiment, such as Figure 4 As shown, the PFC circuit 210 also includes a third capacitor C3 and a third resistor R3; the first end of the third capacitor C3 is connected to the first output pin of the rectifier 110, and the second end of the third capacitor C3 is connected to the second output pin of the rectifier 110; the first end of the third resistor R3 is connected to the first end of the third capacitor C3, and the second end of the third resistor R3 is connected to the second end of the third capacitor C3.

[0057] Among them, the third capacitor C3 is a filter capacitor, and the third resistor R3 is a varistor. The third resistor R3 plays the role of absorbing surge voltage and protecting downstream devices.

[0058] By connecting a third capacitor C3 and a third resistor R3 in parallel between the first and second output pins of the rectifier 110, the third resistor R3 can absorb surge voltage and protect downstream devices; the third capacitor C3 can absorb the pulse portion of the output of the rectifier 110, thereby better reducing the output ripple voltage and ripple current of the rectifier 110, improving the stability and performance of the product, and extending the product's lifespan.

[0059] In one embodiment, such as Figure 3 As shown, the power failure control circuit also includes a power-on surge protection module 120; the power-on surge protection module 120 is connected to the input terminal of the rectifier module 10, and the power-on surge protection module 120 is used to connect to the control chip 50.

[0060] The surge protection module 120 is connected to the rectifier module 10 and the control chip 50 respectively. When the circuit is powered on, it can limit the charging current to a safe range, avoid damage to circuit components and subsequent circuits, thereby extending the service life of the control circuit and reducing the failure rate, and improving the reliability of the circuit.

[0061] For example, the power-on surge protection module 120 may include a thermistor, a relay, and a first transistor. The thermistor is connected in series at the input terminal of the rectifier module 10. The first terminal of the relay is connected to the collector of the first transistor, the second terminal of the relay is connected to the power supply, and the third terminal of the relay is connected across the thermistor. The base of the first transistor is connected to the control chip 50, and the emitter of the first transistor is connected to the transformer isolation output ground. Because the first capacitor C1 has a large capacitance, it will generate a large charging current when powered on, which may damage the rectifier components. By adding a thermistor, the power-on charging current can be limited to a safe range. During normal operation, the control chip controls the relay to conduct, and the current flows through the relay to the rectifier module. It should be noted that the power supply can be, but is not limited to, a 12V DC power supply.

[0062] In one embodiment, such as Figure 3As shown, the switching power supply module 30 includes a transformer module 310, a first voltage conversion module 320, and a second voltage conversion module 330; the auxiliary device 70 includes a first auxiliary operation module 710 and a second auxiliary operation module 720; the transformer module 310 is connected to the power supply module 40, the first voltage conversion module 320 is connected to the transformer module 310, and the second voltage conversion module 330 is connected to the transformer module 310; the first voltage conversion module 320 is used to supply power to the first auxiliary operation module 710, and the second voltage conversion module 330 is used to supply power to the second auxiliary operation module 720.

[0063] The first auxiliary operation module 710 includes an inverter circuit control module for controlling the load 60; the second auxiliary operation module 720 includes a display button module; the inverter circuit control module is connected to the first voltage conversion module 320 and the power output module 20, and the display button module is connected to the second voltage conversion module 330. The first voltage conversion module 320 can output a 15V electrical signal, and the second voltage conversion module 330 can output a 12V electrical signal.

[0064] The transformer module 310 can be used to perform voltage conversion processing on the electrical signal transmitted by the rectifier module 10, and then transmit the voltage-converted electrical signal to the first voltage conversion module 320 and the second voltage conversion module 330 respectively, so that the first voltage conversion module 320 and the second voltage conversion module 330 can perform corresponding voltage conversion on the electrical signal, and then the first voltage conversion module 320 supplies power to the inverter circuit control module, and the second voltage conversion module 330 supplies power to the display button module. When the input power is disconnected, the electrical energy stored in the power extraction module 40 is quickly depleted, and the electrical signal obtained by the switching power supply module 30 will automatically shut down due to insufficient voltage. This achieves the purpose of quickly cutting off power to the inverter circuit control module and the display button module and other auxiliary equipment 70 after the input power is disconnected, thereby achieving the purpose of quickly shutting down the auxiliary equipment 70, preventing the display button module from continuing to display or triggering corresponding functions through the button module, thus avoiding user misoperation of the auxiliary equipment 70 and improving product reliability.

[0065] In one embodiment, a frequency converter is also provided, including a power-off control circuit as described in any of the above.

[0066] Among them, the variable frequency equipment can be, but is not limited to, variable frequency portable air conditioners or variable frequency dehumidifiers.

[0067] For a detailed description of the power-off control circuit, please refer to the specific description of the power-off control circuit in the above embodiments, which will not be repeated here.

[0068] In the above embodiments, a power-off control circuit is installed within the frequency converter. This circuit includes a rectifier module, a power output module, a switching power supply module, and a power-taking module. The input terminal of the rectifier module is connected to the input power supply. The power output module is connected to the output terminal of the rectifier module and supplies power to the load. The output terminal of the switching power supply module is connected to auxiliary equipment. The first terminal of the power-taking module is connected between the output terminal of the rectifier module and the power output module, and the second terminal is connected to the input terminal of the switching power supply module. The power-taking module is configured such that when the input power is disconnected, the power is consumed, the voltage drops, and the switching power supply shuts down, achieving rapid power-off of the switching power supply output terminal. This application, by setting a power-taking module between the output terminal of the rectifier module and the power output module, and connecting the power-taking module to the switching power supply module, enables the power-taking module to obtain an electrical signal from the output terminal of the rectifier module, and the switching power supply module to draw power from the power-taking module. Therefore, after the input power is disconnected, the power on the power-taking module is quickly depleted, and the insufficient output voltage of the switching power supply module causes the auxiliary equipment to automatically and quickly shut down, avoiding user misoperation and improving product reliability.

[0069] It should be noted that the frequency converter may also include components such as a housing. A specific frequency converter may include more components than those described in the above embodiments, or combine certain components, or have different component arrangements.

[0070] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A power-off control circuit, characterized in that, include: A rectifier module, wherein the input terminal of the rectifier module is used to connect to an input power supply; A power output module is connected to the output terminal of the rectifier module and is used to supply power to the load. A switching power supply module, wherein the output terminal of the switching power supply module is used to connect to auxiliary equipment; The power supply module has a first end connected between the output end of the rectifier module and the power output module, and a second end connected to the input end of the switching power supply module. The power supply module is configured such that when the input power is disconnected, the power is consumed, the voltage drops, and the switching power supply is turned off.

2. The power-off control circuit according to claim 1, characterized in that, The rectifier module includes rectifier devices; the power output module includes a PFC circuit, a first resistor, and a first capacitor. The first end of the first resistor is connected to the first output pin of the rectifier, the second end of the first resistor is connected to the negative terminal of the first capacitor, and the positive terminal of the first capacitor is connected to the load. The PFC circuit is connected to the positive and negative terminals of the first capacitor, and the PFC circuit is connected to the second output pin of the rectifier; the first end of the power supply module is connected between the second output pin of the rectifier and the PFC circuit.

3. The power-off control circuit according to claim 2, characterized in that, The PFC circuit includes a first switching transistor, a first inductor, a first diode, and a second resistor. The first end of the first inductor is connected to the first end of the power extraction module and the second output pin of the rectifier, respectively. The second end of the first inductor is connected to the drain of the first switching transistor and the anode of the first diode, respectively. The cathode of the first diode is connected to the positive terminal of the first capacitor. The source of the first switching transistor is connected to the negative terminal of the first capacitor, and the gate of the first switching transistor is used to connect to the control chip; the first end of the second resistor is connected to the gate of the first switching transistor, and the second end of the second resistor is connected to the source of the first switching transistor.

4. The power-off control circuit according to claim 3, characterized in that, The power supply module includes a second diode and a second capacitor; The anode of the second diode is connected between the rectifier and the first terminal of the first inductor, the cathode of the second diode is connected to the positive terminal of the second capacitor, the negative terminal of the second capacitor is connected to the negative terminal of the first capacitor, and the input terminal of the switching power supply module is connected between the cathode of the second diode and the positive terminal of the second capacitor.

5. The power-off control circuit according to claim 4, characterized in that, The capacitance of the second capacitor is less than that of the first capacitor.

6. The power-off control circuit according to claim 3, characterized in that, The PFC circuit also includes a third capacitor and a third resistor; The first end of the third capacitor is connected to the first output pin of the rectifier, and the second end of the third capacitor is connected to the second output pin of the rectifier; the first end of the third resistor is connected to the first end of the third capacitor, and the second end of the third resistor is connected to the second end of the third capacitor.

7. The power-off control circuit according to claim 3, characterized in that, It also includes a power-on surge protection module; the power-on surge protection module is connected to the input terminal of the rectifier module, and the power-on surge protection module is used to connect to the control chip.

8. The power-off control circuit according to any one of claims 1 to 7, characterized in that, The switching power supply module includes a transformer module, a first voltage conversion module, and a second voltage conversion module; the auxiliary equipment includes a first auxiliary operation module and a second auxiliary operation module. The transformer module is connected to the power supply module, the first voltage conversion module is connected to the transformer module, and the second voltage conversion module is connected to the transformer module; the first voltage conversion module is used to supply power to the first auxiliary operation module, and the second voltage conversion module is used to supply power to the second auxiliary operation module.

9. The power-off control circuit according to claim 8, characterized in that, The first auxiliary operation module includes an inverter circuit control module, which is used to control the load; the second auxiliary operation module includes a display button module. The inverter circuit control module is connected to the first voltage conversion module and the power output module, and the display button module is connected to the second voltage conversion module.

10. A frequency converter, characterized in that, Includes the power-off control circuit as described in any one of claims 1 to 9.

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