Switching power supply drop detection circuit and switching power supply

Abstract

The utility model provides a switching power supply drop detection circuit and a switching power supply, and relates to the technical field of switching power supplies. The switching power supply drop detection circuit is applied to the grid-connected inverter, the grid-connected inverter at least comprises a control device, the control device comprises different working states, the control device is connected with a power supply unit, and the switching power supply drop detection circuit is connected with the power supply unit and the control device. The switching power supply drop detection circuit is used for detecting power supply voltage of the power supply unit. When the power supply voltage is smaller than a preset value, the switching power supply drop detection circuit provides a first detection signal for the control device, so that the control device switches the working state according to the first detection signal and adjusts the load power of the grid-connected inverter. According to the utility model, the output state of the switching power supply can be rapidly detected, so that a detection signal can be timely fed back to a control device in the grid-connected inverter when power failure occurs, and then the rear-end load power can be rapidly adjusted through the control device, and the operation state of the grid-connected inverter can be maintained.

Description

Technical Field

[0001] The utility model relates to the technical field of switching power supplies, and in particular to a switching power supply drop detection circuit and a switching power supply. Background Art

[0002] In addition to converting DC power into AC power, grid-connected inverters can also synchronize the frequency and phase of the output AC power with the mains power so that the output AC power can be returned to the mains power. Grid-connected inverters are commonly used in applications where a DC voltage source is connected to the grid.

[0003] In the prior art, a switching power supply is usually used to provide a stable DC voltage for a back-end grid-connected inverter. However, in the process of achieving stable output, the switching power supply will inevitably have voltage fluctuations, which will cause the back-end load, such as the grid-connected inverter, to operate unstably.

[0004] On this basis, there is an urgent need for a detection circuit that can quickly detect the output status of the switching power supply so that when a power outage occurs, the detection signal can be promptly fed back to the control device in the grid-connected inverter, and then the back-end load power can be quickly adjusted through the control device to maintain the operating status of the grid-connected inverter. Utility Model Content

[0005] The purpose of the utility model is to provide a switching power supply drop detection circuit and a switching power supply, which can quickly detect the output state of the switching power supply so that when a power failure occurs, a detection signal can be fed back to a control device in a grid-connected inverter in a timely manner, and then the rear-end load power can be quickly adjusted through the control device to maintain the operating state of the grid-connected inverter.

[0006] The utility model provides a technical solution:

[0007] On the one hand, the utility model provides a switching power supply drop detection circuit, which is applied to a grid-connected inverter, wherein the grid-connected inverter at least includes a control device, the control device includes different working states, the control device is connected to a power supply unit, and the switching power supply drop detection circuit is respectively connected to the power supply unit and the control device; the switching power supply drop detection circuit is used to detect the supply voltage of the power supply unit; wherein, when the supply voltage is less than a preset value, the switching power supply drop detection circuit provides a first detection signal to the control device, so that the control device switches the working state according to the first detection signal, and adjusts the load power of the grid-connected inverter.

[0008] Preferably, the switching power supply drop detection circuit comprises: a charging module and a detection module; the charging module is connected to the detection module; the charging module and the detection module are also used to connect to a power supply unit; the detection module is also connected to the control device;

[0009] When the preset value is a threshold voltage, wherein, when the supply voltage is less than the threshold voltage, the detection module provides a first detection signal to the control device; when the supply voltage is greater than or equal to the threshold voltage, the detection module provides a second detection signal to the control device; the first detection signal and the second detection signal are opposite signals.

[0010] Preferably, the detection module includes a first switch unit and a first resistor; the control end of the first switch unit is connected to the power supply unit; the first end of the first switch unit is connected to the output end of the charging module; the second end of the first switch unit is connected to the control device and the first end of the first resistor as the output end of the detection module; the second end of the first resistor is grounded; wherein, when the supply voltage is less than the threshold voltage, the switch unit is turned on, and the detection module provides a high level signal to the control device;

[0011] When the supply voltage is greater than or equal to the threshold voltage, the switch unit is turned off, and the detection module provides a low level signal to the control device.

[0012] Preferably, the first switch unit includes a first switch tube and a first driving resistor;

[0013] The control end of the first switch tube is connected to the power supply unit through the first driving resistor; the first end of the first switch tube is connected to the output end of the charging module, and the second end of the first switch tube is respectively connected to the control device and the first end of the first resistor.

[0014] Preferably, the detection module includes a second switch unit and a second resistor; the second switch unit includes at least one switch tube;

[0015] The first end of the second switch unit is connected to the power supply unit; the second end of the second switch unit is connected to the output end of the charging module; the third end of the second switch unit is connected to the first end of the second resistor and the control device respectively; the second end of the second resistor is also connected to the power supply unit, wherein when the supply voltage is less than the threshold voltage, the second switch unit is turned on, and the detection module provides a low level signal to the control device;

[0016] When the supply voltage is greater than or equal to the threshold voltage, the second switch unit is turned off, and the detection module provides a high level signal to the control device.

[0017] Preferably, when the number of the switch tubes is two and the second switch unit includes a second switch tube and a third switch tube, the second switch unit further includes a second driving resistor;

[0018] The control end of the second switch tube is connected to the power supply unit through the second driving resistor, and the first end of the second switch tube is connected to the output end of the charging module; the second end of the second switch tube is connected to the control end of the third switch tube; the first end of the third switch tube is grounded; the second end of the second switch tube is respectively connected to the control device and the first end of the second resistor;

[0019] When the supply voltage is less than the threshold voltage, the second switch tube and the third switch tube are both turned on; the detection module provides a low level signal to the control device;

[0020] When the supply voltage is greater than or equal to the threshold voltage, the second switch tube and the third switch tube are both turned off, and the detection module provides a low level signal to the control device.

[0021] Preferably, the second switch unit also includes a third driving resistor and a third resistor; the second end of the second switch tube is connected to the first end of the third driving resistor; the second end of the third driving resistor is respectively connected to the control end of the third switch tube and the first end of the third resistor; the first end of the third switch tube is connected to the second end of the third resistor and is grounded.

[0022] Preferably, the charging module includes a capacitor component and a diode component; the capacitor component includes at least one capacitor; the diode component includes at least one diode;

[0023] The anode of the diode component is connected to the power supply unit; the cathode of the diode component is connected to the first end of the capacitor component; and the second end of the capacitor component is grounded.

[0024] Preferably, the switching power supply drop detection circuit further includes a first voltage-dividing resistor and a second voltage-dividing resistor;

[0025] The first end of the first voltage-dividing resistor is connected to the power supply unit, and the second end of the first voltage-dividing resistor is connected to the first end of the second voltage-dividing resistor and the anode of the diode assembly respectively.

[0026] In a second aspect, the utility model further provides a switching power supply, comprising the switching power supply drop detection circuit described in any one of the first aspects above.

[0027] The beneficial effects of a switching power supply drop detection circuit and a switching power supply provided by the utility model are:

[0028] A switching power supply drop detection circuit is provided, which is applied to a grid-connected inverter, wherein the grid-connected inverter at least includes a control device, the control device includes different working states, the control device is connected to a power supply unit, and the switching power supply drop detection circuit is connected to the power supply unit and the control device respectively; the switching power supply drop detection circuit is used to detect the power supply voltage of the power supply unit. When the power supply voltage is less than a preset value, the switching power supply drop detection circuit provides a first detection signal to the control device, so that the control device switches the working state according to the first detection signal and adjusts the load power of the grid-connected inverter. The switching power supply drop detection circuit and the switching power supply provided by the utility model can quickly detect the output state of the switching power supply, so that when a power failure occurs, the detection signal can be fed back to the control device in the grid-connected inverter in a timely manner, and then the back-end load power can be quickly adjusted through the control device to maintain the operating state of the grid-connected inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 This is one of the structural schematic diagrams of the switching power supply drop detection circuit provided by the utility model;

[0031] Figure 2 The second structural diagram of the switching power supply drop detection circuit provided by the utility model;

[0032] Figure 3 The third structural diagram of the switching power supply drop detection circuit provided by the utility model;

[0033] Figure 4 This is one of the structural schematic diagrams of the detection module in the utility model;

[0034] Figure 5 This is one of the circuit schematics of the detection module in the utility model;

[0035] Figure 6 This is the second structural diagram of the detection module in the utility model;

[0036] Figure 7 This is the second circuit schematic diagram of the detection module in the utility model;

[0037] Figure 8 This is the third circuit schematic diagram of the detection module in the utility model;

[0038] Fig. 9This is a schematic diagram of the structure of the charging module in the utility model;

[0039] Fig.10 This is a circuit diagram of the charging module in the utility model;

[0040] Fig.11 This is the fourth circuit schematic diagram of the detection module in the utility model;

[0041] Fig.12 The utility model is a circuit diagram of the switching power supply drop detection circuit.

[0042] Icon: 100-switching power supply drop detection circuit; 200-control device; 300-power supply unit; 301-first power supply; 302-second power supply; 101-charging module; 102-detection module; 201-first switching unit; 202-second switching unit; 1001-capacitor component; 1002-diode component; R1-first resistor; R2-first driving resistor; R3-second resistor; R4-second driving resistor; R5-third driving resistor; R6-third resistor; R7-first voltage-dividing resistor; R8-second voltage-dividing resistor; Q1-first switch tube; Q2-second switch tube; Q3-third switch tube. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0046] In the description of the present utility model, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the utility model product is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present utility model.

[0047] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0048] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] As described in the background technology, the prior art usually uses a switching power supply to provide a stable DC voltage for a back-end grid-connected inverter. However, in the process of achieving stable output, the switching power supply will inevitably have voltage fluctuations, which will cause the back-end load, such as the grid-connected inverter, to operate unstable.

[0050] On this basis, the utility model provides a switching power supply drop detection scheme, which can quickly detect the output status of the switching power supply, so that when a power failure occurs, a detection signal can be promptly fed back to the control device 200 in the grid-connected inverter, and then the back-end load power can be quickly adjusted through the control device 200 to maintain the operating state of the grid-connected inverter.

[0051] The switching power supply drop detection solution will be introduced in detail below.

[0052] Example

[0053] On the one hand, see Figure 1The utility model provides a switching power supply drop detection circuit 100, which is applied to a grid-connected inverter, wherein the grid-connected inverter at least includes a control device 200, the control device 200 includes different working states, the control device 200 is connected to a power supply unit 300, and the switching power supply drop detection circuit 100 is respectively connected to the power supply unit 300 and the control device 200; the switching power supply drop detection circuit 100 is used to detect the supply voltage of the power supply unit 300.

[0054] In this example, see Figure 2 , the power supply unit 300 includes a first power supply 301 and a second power supply 302. The first power supply 301 can provide a working voltage, such as 12V, for the switching power supply drop detection circuit 100. In a possible implementation method, the working voltage is a voltage that enables the switching power supply drop detection circuit 100 to work stably, so that the switching power supply drop detection circuit 100 can detect the power supply voltage of the power supply unit 300 when it is working normally. The second power supply 302 can provide a stable working voltage, such as 3.3V, for the control device 200. It should be noted that the first power supply 301 and the second power supply 302 involved in this embodiment are only two outputs of the power supply unit 300, which provide power supply voltage for the switching power supply drop detection circuit 100 and the control device 200. The main output of the above-mentioned power supply unit 300 is to provide power for the grid-connected inverter, that is, output to the bus capacitor through the grid-connected inverter, boost inductor, power semiconductor, diode, etc., to provide power for the inverter.

[0055] In this embodiment, when the supply voltage is less than a preset value, the switching power supply drop detection circuit 100 provides a first detection signal to the control device 200, so that the control device 200 switches the working state according to the first detection signal and adjusts the load power. After receiving the first detection signal, the control device 200 can respond quickly, switch to different working states, and adjust the load power in time to improve the operation reliability.

[0056] In a possible implementation, the preset value can be directly set to the on-voltage of the switching power supply drop detection circuit 100, that is, the threshold voltage described in this article, see Figure 3 The switching power supply drop detection circuit 100 includes: a charging module 101 and a detection module 102; the charging module 101 is connected to the detection module 102; the charging module 101 and the detection module 102 are also used to connect to the power supply unit 300; the detection module 102 is also connected to the control device 200.

[0057] When the preset value is a threshold voltage, when the supply voltage is less than the threshold voltage, the detection module 102 provides a first detection signal to the control device 200; when the supply voltage is greater than or equal to the threshold voltage, the detection module 102 provides a second detection signal to the control device 200; the first detection signal and the second detection signal are opposite signals.

[0058] In this embodiment, the detection module 102 is used to provide different detection signals to the control device 200 under different states between the power supply voltage and the threshold voltage, and the charging module 101 is connected to the detection module 102 so that when the power supply unit 300 is working normally, it is charged according to the output voltage of the power supply unit 300, so that when the power supply unit 300 loses power, the second detection signal sent by the detection module 102 to the control device 200 is maintained for a short time to ensure the stability of the back-end operation.

[0059] It should be noted that the threshold voltage can be adaptively adjusted as needed. In this embodiment, after the preset value is set as the on-voltage of the switching power supply drop detection circuit 100, the acquisition circuit can be directly constructed by simple electronic components such as switching tubes without setting a specific voltage acquisition module, thereby reducing the device cost and improving the applicability of the solution.

[0060] In one possible implementation, see Figure 4 , the detection module 102 includes a first switch unit 201 and a first resistor R1; the control end of the first switch unit 201 is connected to the power supply unit 300; the first end of the first switch unit 201 is connected to the output end of the charging module 101; the second end of the first switch unit 201 is connected to the control device 200 and the first end of the first resistor R1 as the output end of the detection module 102; the second end of the first resistor R1 is grounded. When the power supply voltage is less than the threshold voltage, the first switch unit 201 is turned on, and the detection module 102 provides a high-level signal to the control device 200; when the power supply voltage is greater than or equal to the threshold voltage, the first switch unit 201 is turned off, and the detection module 102 provides a low-level signal to the control device 200.

[0061] In this embodiment, please refer to Figure 5 , the first switch unit 201 includes a first switch tube Q1 and a first driving resistor R2;

[0062] The control end of the first switch tube Q1 is connected to the power supply unit 300 through the first driving resistor R2; the first end of the first switch tube Q1 is connected to the output end of the charging module 101, and the second end of the first switch tube Q1 is respectively connected to the control device 200 and the first end of the first resistor R1.

[0063] When the power supply unit 300 normally outputs 12V, the voltage at the first driving resistor R2 is 12V. At the same time, the power supply unit 300 is also connected to the charging module 101, which makes the voltage at the first end (emitter) of the first switch tube Q1 less than 12V.

[0064] When the voltage between the first end of the first switch tube Q1 and the control end of the first switch tube Q1 is greater than the voltage drop of the first switch tube Q1 itself, the first switch tube Q1 is turned on, and the second end (collector) of the first switch tube Q1 provides a high level signal to the control device 200.

[0065] When the voltage between the first end of the first switch tube Q1 and the control end of the first switch tube Q1 is less than the voltage drop of the first switch tube Q1 itself, the first switch tube Q1 is turned off, and the first resistor R1 provides a low level signal to the control device 200 .

[0066] In a possible embodiment, in order to meet the actual scenarios of light load and heavy load of the power supply, when the power supply unit 300 stably outputs 12V voltage, the voltage of the first terminal of the first switch tube Q1 can be adjusted through the structure of the front end of the first switch unit 201, for example, the structure of each device in the charging module 101, so as to maintain it at 10.95V. At this time, only when the voltage at the control end of the first switch tube Q1 is lower than 10.25V, the first switch tube Q1 can be turned on, that is, the threshold voltage is 10.25V at this time. When the power supply voltage of the power supply unit 300 drops to 10.25V, the detection module 102 will control the back-end device 200 to send the first detection signal to prompt the power supply unit 300 that the power supply drops. At the same time, it can also avoid the detection module 102 from sending the first detection signal to the back end when the voltage drops by 0.7V due to false touch, that is, the voltage fluctuation range is too small.

[0067] In another possible implementation, see Figure 6 , the detection module 102 includes a second switch unit 202 and a second resistor R3; the second switch unit 202 includes at least one switch tube;

[0068] The first end of the second switch unit 202 is connected to the power supply unit 300; the second end of the second switch unit 202 is connected to the output end of the charging module 101; the third end of the second switch unit 202 is respectively connected to the first end of the second resistor R3 and the control device 200; the second end of the second resistor R3 is also connected to the power supply unit 300. The power supply unit 300 provides a 3.3V voltage to the second resistor R3.

[0069] In this embodiment, when the supply voltage is less than the threshold voltage, the second switch unit 202 is turned on, and the detection module 102 provides a low level signal to the control device 200. When the supply voltage is greater than or equal to the threshold voltage, the second switch unit 202 is turned off, and the detection module 102 provides a high level signal to the control device 200.

[0070] In one possible implementation, see Figure 7 , when the number of switch tubes is two, and the second switch unit 202 includes a second switch tube Q2 and a third switch tube Q3, the second switch unit 202 further includes a second driving resistor R4;

[0071] The control end of the second switch tube Q2 is connected to the power supply unit 300 through the second driving resistor R4, and the first end of the second switch tube Q2 is connected to the output end of the charging module 101; the second end of the second switch tube Q2 is connected to the control end of the third switch tube Q3; the first end of the third switch tube Q3 is grounded; the second end of the second switch tube Q2 is respectively connected to the control device 200 and the first end of the second resistor R3.

[0072] In this embodiment, when the supply voltage is less than the threshold voltage, the second switch tube Q2 and the third switch tube Q3 are both turned on; the detection module 102 provides a low level signal to the control device 200 .

[0073] When the supply voltage is greater than or equal to the threshold voltage, the second switch tube Q2 and the third switch tube Q3 are both turned off, and the detection module 102 provides a low level signal to the control device 200 .

[0074] In this embodiment, when the power supply unit 300 normally outputs a voltage of 12V, the voltage at the second driving resistor R4 is 12V. At the same time, the first end (emitter) of the second switch tube Q2 is connected to the power supply unit 300 through the charging module 101 and other devices, which makes the voltage at the first end (emitter) of the second switch tube Q2 less than 12V.

[0075] When the voltage between the first end of the second switch tube Q2 and the control end of the second switch tube Q2 is greater than the voltage drop of the second switch tube Q2 itself, the second switch tube Q2 is turned on, and the second end of the second switch tube Q2 outputs a voltage higher than 3.3V. At this time, in order to avoid damaging the control device 200, the output voltage can be converted to a voltage of up to 3.3V through the third switch tube Q3 and the second resistor R3. When the second switch tube Q2 is turned on, the third switch tube Q3 is also turned on. At this time, the output voltage of the second end of the second switch tube Q2 can be pulled down by the third switch tube Q3 to obtain a low-level signal, so as to provide a low-level signal to the control device 200.

[0076] Similarly, when the 12V power supply voltage drops and the voltage between the first end of the second switch tube Q2 and the control end of the second switch tube Q2 is less than the voltage drop of the second switch tube Q2 itself, the second switch tube Q2 and the third switch tube Q3 are cut off. At this time, the second resistor R3 provides a high-level signal to the control device 200.

[0077] In a possible embodiment, in order to meet the actual scenarios of light load and heavy load of the power supply, when the power supply unit 300 stably outputs 12V voltage, the voltage of the first terminal of the second switch tube Q2 can be adjusted through the structure of the front end of the second switch unit 202, for example, the structure of each device in the charging module 101, so as to maintain it at 10.95V. At this time, only when the voltage at the control end of the second switch tube Q2 is lower than 10.25V, the second switch tube Q2 can be turned on, that is, the threshold voltage is 10.25V at this time. When the power supply voltage of the power supply unit 300 drops to 10.25V, the detection module 102 will control the back-end device 200 to send the first detection signal to prompt the power supply unit 300 that the power supply drops. At the same time, it can also avoid the detection module 102 from sending the first detection signal to the back end when the voltage drops by 0.7V due to false touch, that is, the voltage fluctuation range is too small.

[0078] In one possible implementation, see Figure 8 The second switch unit 202 also includes a third driving resistor R5 and a third resistor R6; the second end of the second switch tube Q2 is connected to the first end of the third driving resistor R5; the second end of the third driving resistor R5 is respectively connected to the control end of the third switch tube Q3 and the first end of the third resistor R6; the first end of the third switch tube Q3 is connected to the second end of the third resistor R6 and is grounded.

[0079] In one possible implementation, see Fig. 9 The charging module 101 includes a capacitor component 1001 and a diode component 1002, wherein the anode of the diode component 1002 is connected to the power supply unit 300; the cathode of the diode component 1002 is connected to the first end of the capacitor component 1001; and the second end of the capacitor component 1001 is connected to the detection module 102. The capacitor component 1001 includes at least one capacitor; the diode component 1002 includes at least one diode. Please refer to Fig.10 When the capacitor assembly 1001 includes multiple capacitors, the first ends of the multiple capacitors are respectively connected to the cathode end of the diode assembly 1002 and the detection module 102; the second ends of the multiple capacitors are grounded. When the diode assembly 1002 includes multiple diodes, the diodes are connected in parallel, that is, the anode of each diode is connected to the power supply unit 300; the cathode of each diode is connected to the capacitor assembly 1001.

[0080] In this embodiment, the capacitor component 1001 is used to charge when the power supply unit 300 outputs stably, and at the moment when the power supply unit 300 drops, since the capacitors in the capacitor component 1001 cannot form a discharge circuit, it is equivalent to a battery, which can maintain the operation of the detection module 102, avoid voltage fluctuations in the power supply unit 300 in a short period of time, cause false triggering of the detection signal, and further affect the operation of the back-end control device 200. Among them, the diode component 1002 can be used to prevent the capacitor component 1001 from reverse discharge when the power supply unit 300 drops, and as an electrical device, it can further adjust the voltage of the detection module 102, especially the voltage of the first end of the second switch tube Q2.

[0081] In this embodiment, please refer to Fig.11 The switching power supply drop detection circuit 100 also includes a first voltage-dividing resistor R7 and a second voltage-dividing resistor R8; the first end of the first voltage-dividing resistor R7 is connected to the power supply unit 300, and the second end of the first voltage-dividing resistor R7 is respectively connected to the first end of the second voltage-dividing resistor R8 and the anode of the diode component 1002; the second end of the second voltage-dividing resistor R8 is grounded.

[0082] In summary, please refer to Fig.12 The embodiment of the utility model provides a switching power supply drop detection circuit 100. When the power supply unit 300 stably outputs a 12V voltage, in order to make the threshold voltage 10.25V, the first voltage-dividing resistor R7 and the second voltage-dividing resistor R8 can divide the voltage through resistance, so that the input voltage of the charging module 101 is 11.31V, and then after passing through the diode component 1002, the voltage of the first end of the second switch tube Q2 can be adjusted to 10.95V. At this time, the control terminal voltage of the second switch tube Q2 is maintained at 12V. When the voltage between the first end of the second switch tube Q2 and the control end of the second switch tube Q2 is less than the self-voltage drop of the second switch tube Q2, the second switch tube Q2 and the third switch tube Q3 are both turned off. At this time, the second resistor R3 acts as a pull-up resistor, which can pull up the voltage at the collector of the third switch tube Q3 to provide a high-level signal to the control device 200.

[0083] When the power supply unit 300 outputs a stable power failure, the charging module 101 can provide a voltage to the detection module 102 for a short time to maintain the current state, so that the voltage at the first end of the second switch tube Q2 is maintained at 10.95V. When the voltage at the control end of the second switch tube Q2 drops to 10.25V, the voltage between the first end of the second switch tube Q2 and the control end of the second switch tube Q2 is greater than the voltage drop of the second switch tube Q2 itself, and the second switch tube Q2 and the third switch tube Q3 are both turned on. At this time, the voltage at the collector of the third switch tube Q3 is pulled down to provide a low-level signal to the control device 200.

[0084] In summary, the switching power supply drop detection circuit provided by the utility model can quickly detect the output state of the switching power supply, so that when a power failure occurs, a detection signal can be promptly fed back to the control device in the grid-connected inverter, and then the back-end load power can be quickly adjusted through the control device to maintain the operating state of the grid-connected inverter.

[0085] In a second aspect, the present invention further provides a switching power supply, comprising the switching power supply drop detection circuit 100 of any one of the above-mentioned first aspects.

[0086] The above-mentioned switching power supply includes all the technical features and technical effects of the switching power supply drop detection circuit 100, which will not be repeated here.

[0087] In summary, the embodiment of the utility model provides a switching power supply drop detection circuit, which is applied to a grid-connected inverter, wherein the grid-connected inverter at least includes a control device, the control device includes different working states, the control device is connected to the power supply unit, and the switching power supply drop detection circuit is connected to the power supply unit and the control device respectively; the switching power supply drop detection circuit is used to detect the power supply voltage of the power supply unit. Wherein, when the power supply voltage is less than a preset value, the switching power supply drop detection circuit provides a first detection signal to the control device, so that the control device switches the working state according to the first detection signal and adjusts the load power of the grid-connected inverter. It can quickly detect the output state of the switching power supply, so that when a power failure occurs, the detection signal can be fed back to the control device in the grid-connected inverter in time, and then the back-end load power can be quickly adjusted through the control device to maintain the operating state of the grid-connected inverter.

[0088] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A switching power supply drop detection circuit is applied to a grid-connected inverter, wherein: The grid-connected inverter at least includes a control device, the control device includes different working states, the control device is connected to the power supply unit, and is characterized in that the switching power supply drop detection circuit is connected to the power supply unit and the control device respectively; the switching power supply drop detection circuit is used to detect the power supply voltage of the power supply unit; wherein, When the supply voltage is less than a preset value, the switching power supply drop detection circuit provides a first detection signal to the control device, so that the control device switches the working state according to the first detection signal and adjusts the load power of the grid-connected inverter.

2. The switching power supply drop detection circuit according to claim 1, characterized in that: The switching power supply drop detection circuit comprises: a charging module and a detection module; the charging module is connected to the detection module; the charging module and the detection module are also used to connect to a power supply unit; the detection module is also connected to the control device; When the preset value is a threshold voltage, wherein, when the supply voltage is less than the threshold voltage, the detection module provides a first detection signal to the control device; when the supply voltage is greater than or equal to the threshold voltage, the detection module provides a second detection signal to the control device; the first detection signal and the second detection signal are opposite signals.

3. The switching power supply drop detection circuit according to claim 2, characterized in that: The detection module includes a first switch unit and a first resistor; the control end of the first switch unit is connected to the power supply unit; the first end of the first switch unit is connected to the output end of the charging module; the second end of the first switch unit is used as the output end of the detection module, connected to the control device and the first end of the first resistor; the second end of the first resistor is grounded; wherein, When the supply voltage is less than the threshold voltage, the first switch unit is turned on, and the detection module provides a high level signal to the control device; When the supply voltage is greater than or equal to the threshold voltage, the first switch unit is turned off, and the detection module provides a low level signal to the control device.

4. The switching power supply drop detection circuit according to claim 3, characterized in that: The first switch unit includes a first switch tube and a first driving resistor; The control end of the first switch tube is connected to the power supply unit through the first driving resistor; the first end of the first switch tube is connected to the output end of the charging module, and the second end of the first switch tube is respectively connected to the control device and the first end of the first resistor.

5. The switching power supply drop detection circuit according to claim 2, characterized in that: The detection module includes a second switch unit and a second resistor; the second switch unit includes at least one switch tube; The first end of the second switch unit is connected to the power supply unit; the second end of the second switch unit is connected to the output end of the charging module; the third end of the second switch unit is respectively connected to the first end of the second resistor and the control device; the second end of the second resistor is also connected to the power supply unit, wherein, When the supply voltage is less than the threshold voltage, the second switch unit is turned on, and the detection module provides a low level signal to the control device; When the supply voltage is greater than or equal to the threshold voltage, the second switch unit is turned off, and the detection module provides a high level signal to the control device.

6. The switching power supply drop detection circuit according to claim 5, characterized in that: When the number of the switch tubes is two, and the second switch unit includes a second switch tube and a third switch tube, the second switch unit further includes a second driving resistor; The control end of the second switch tube is connected to the power supply unit through the second driving resistor, and the first end of the second switch tube is connected to the output end of the charging module; the second end of the second switch tube is connected to the control end of the third switch tube; the first end of the third switch tube is grounded; the second end of the second switch tube is respectively connected to the control device and the first end of the second resistor; When the supply voltage is less than the threshold voltage, the second switch tube and the third switch tube are both turned on; the detection module provides a low level signal to the control device; When the supply voltage is greater than or equal to the threshold voltage, the second switch tube and the third switch tube are both turned off, and the detection module provides a low level signal to the control device.

7. The switching power supply drop detection circuit according to claim 6, characterized in that: The second switch unit also includes a third driving resistor and a third resistor; the second end of the second switch tube is connected to the first end of the third driving resistor; the second end of the third driving resistor is respectively connected to the control end of the third switch tube and the first end of the third resistor; the first end of the third switch tube is connected to the second end of the third resistor and is grounded.

8. The switching power supply drop detection circuit according to claim 2, characterized in that: The charging module includes a capacitor component and a diode component; the capacitor component includes at least one capacitor; the diode component includes at least one diode; The anode of the diode component is connected to the power supply unit; the cathode of the diode component is connected to the first end of the capacitor component; and the second end of the capacitor component is grounded.

9. The switching power supply drop detection circuit according to claim 8, characterized in that: The switching power supply drop detection circuit also includes a first voltage-dividing resistor and a second voltage-dividing resistor; The first end of the first voltage-dividing resistor is connected to the power supply unit, and the second end of the first voltage-dividing resistor is connected to the first end of the second voltage-dividing resistor and the anode of the diode assembly respectively.

10. A switching power supply, characterized in that: The switching power supply drop detection circuit comprises the switching power supply drop detection circuit as described in any one of claims 1 to 9.

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