Low-voltage alarm switching power supply control circuit

Abstract

The utility model discloses a low-voltage alarm switching power supply control circuit, which comprises a filter rectifier module, a voltage transformation module, a filter output module, a battery power supply module and a low-voltage alarm module, the input end of the filter rectifier module is connected with a mains alternating-current power supply; the input end of the voltage transformation module is connected with the output end of the filter rectifier module; the input end of the filtering output module is connected with the output end of the voltage transformation module; the battery power supply module is connected with the filtering output module and the low-voltage alarm module. The battery power supply module is used for storing electric energy, and is used for discharging when the mains supply AC power supply is powered off. And a voltage stabilizing diode ZD1 in the low-voltage alarm module changes the on-off state of the voltage stabilizing diode ZD1 by detecting the output voltage of the battery power supply module, and controls the on-off states of the optical coupler U2 and the triode Q1 by utilizing the on-off state of the voltage stabilizing diode ZD1, thereby controlling the light emitting diode LED4 to be turned on or turned off. And when the voltage output by the battery power supply module is lower than a preset value, the LED lights up to prompt a user that the voltage of the battery power supply module is reduced.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply technology, specifically to a low-voltage alarm switching power supply control circuit. Background Technology

[0002] A switching power supply, also known as a switching power supply, is a high-frequency power conversion device. Its function is to convert a standard voltage into the voltage or current required by the user through different architectures.

[0003] Existing switching power supply products are typically used to provide stable voltage and current to electrical equipment, or to continue supplying power to electrical equipment as an uninterruptible power supply during power outages to protect the equipment from the effects of power outages.

[0004] When the AC mains power supply fails, the switching power supply uses its internal battery to discharge and supply power to the equipment. However, existing switching power supplies lack a power failure alarm module, so they cannot provide timely alerts after a power outage. Furthermore, prolonged discharge can lead to over-discharge of the internal battery, potentially damaging it. Utility Model Content

[0005] To address the shortcomings of existing technologies, a low-voltage alarm switching power supply control circuit is provided.

[0006] To achieve the above objectives, this utility model provides a low-voltage alarm switching power supply control circuit, including a filter rectifier module, a transformer module, a filter output module, a battery power supply module, and a low-voltage alarm module; the input terminal of the filter rectifier module is connected to the AC mains power supply; the input terminal of the transformer module is connected to the output terminal of the filter rectifier module; the input terminal of the filter output module is connected to the output terminal of the transformer module; the battery power supply module is connected to both the filter output module and the low-voltage alarm module; the low-voltage alarm module includes diode D9, resistor A7, optocoupler U2, Zener diode ZD1, transistor Q1, transistor A26, resistor R10, resistor R27, and light-emitting diode LED4; the anode of diode D9 is connected to the output terminal of the filter output module, and the cathode of diode D9 is connected in series with resistor R7. The other end of resistor R7 is connected to the emitter of transistor Q1 and the emitter of transistor A26, respectively; the second end of optocoupler U2 is connected to the output end of the transformer module, the first end of optocoupler U2 is connected to the positive terminal of Zener diode ZD1, and its negative terminal is connected to resistor A7, the emitter of transistor Q1, the battery power supply module, and the fourth end of optocoupler U2, respectively. The collector of transistor Q1 and the third end of optocoupler U2 are connected to ground, and the base of transistor Q1 is connected to the collector of resistor A7 and transistor A26, respectively; one end of resistor R10 is connected to the output end of the filter output module, and its other end is connected to the base of transistor A26; one end of resistor R27 is connected to the base of transistor Q1, and its other end is connected to the positive terminal of LED4, and the negative terminal of LED4 is grounded.

[0007] According to one embodiment of this utility model, the low-voltage alarm module further includes a fuse F2, a resistor R10, a diode D15, a resistor R24, a resistor R28, a transistor Q2, and a relay U1; the fuse F2 is connected to the output terminal of the filter rectifier module, one end of the resistor R10 is connected to the other end of the fuse F2, the other end of the resistor R10 is connected to the base of the transistor A26, the anode of the diode D15 is connected to the collector of the transistor A26 and the resistor R27, the cathode of the diode D15 is connected to the resistor R24 ​​and the base of the transistor Q2, one end of the resistor R28 is connected to the emitter of the transistor A26, and the other end is connected to the emitter of the transistor Q2, and the collector of the transistor Q2 is connected to the relay U1.

[0008] According to one embodiment of the present invention, the low-voltage alarm module further includes a resistor R45, a transistor A12, and a resistor R8; one end of the resistor R45 is connected to a resistor A7, and the other end is connected to the emitter of the transistor A12; the collector of the transistor A12 is connected to one end of the resistor R8, and the other end of the resistor R8 is connected to the battery power supply module; the collector of the transistor A12 is connected to the base of the transistor Q1 and a resistor R27.

[0009] According to one embodiment of the present invention, it further includes a sampling feedback module, which includes a first voltage regulator component and an optocoupler A16; the first voltage regulator component is respectively connected to the filter output module and the optocoupler A16; the first end of the optocoupler A16 is connected to the filter output module, the second end of the optocoupler A16 is connected to the first voltage regulator component, and the third and fourth ends of the optocoupler A16 are connected to the transformer module.

[0010] According to one embodiment of this utility model, the battery power supply module includes a detection and control component and a power supply component. The input terminal of the detection and control component is connected to a filter output module, and its output terminal is connected to the power supply component. The power supply component includes a diode D10, a fuse F3, a battery BT, a relay A4, a resistor R23, a resistor R1, a light-emitting diode LED1, a diode D7, and a diode D6. The positive terminal of diode D10 is connected to the filter output module, and the negative terminal of diode D10 is connected to the fuse F3 and the resistor A7. The other end of the fuse F3 is connected to the first terminal of the relay A4 and the emitter of the transistor Q1. The negative terminal of the battery BT is grounded, and the positive terminal of the battery BT is connected to a low-voltage alarm module. The circuit consists of a block, the first terminal of relay A4, the emitter of transistor Q1, and one end of resistor R23. The other end of resistor R23 is connected to the output terminal of the transformer module. One end of resistor R1 is connected to the first terminal of relay A4, the positive terminal of battery BT, and resistor R23. Its other end is connected to the positive terminal of LED1. The negative terminal of LED1 is connected to the second terminal of relay A4, the positive terminal of diode D7, and the output terminal of the detection and control component. The negative terminal of diode D7 is connected to the positive terminal of battery BT, resistor R23, and the emitter of transistor Q1. The positive terminal of diode D6 is connected to the third terminal of relay A4, and the negative terminal of diode D6 is connected to the output terminal of the filter output module.

[0011] According to one embodiment of the present invention, the detection control component includes a comparator A24, a battery control unit, a first voltage divider component, and a voltage regulator A6. The comparator A24 has a VCC terminal, a GND terminal, a first connection terminal, a second connection terminal, a third connection terminal, and a fourth connection terminal. The VCC terminal of the comparator A24 is connected to a filter output module. One end of the first voltage divider component is connected to the VCC terminal of the comparator A24, and the other end is grounded. The second and third connection terminals of the comparator A24 are respectively connected to the first voltage divider component, and the GND terminal of the comparator A24 is grounded. The battery control unit has terminals 1, 2, and 3. Terminal 1 of the battery control unit is connected to the positive terminal of diode D7 and the second terminal of relay A4. Terminal 2 of the battery control unit is connected to the first connection terminal of the comparator A24, and terminal 3 of the battery control unit is grounded. The K terminal of the voltage regulator A6 is connected to the second connection terminal of the comparator A24, the R terminal of the voltage regulator A6 is connected to the first voltage divider component, and the A terminal of the voltage regulator A6 is grounded.

[0012] According to one embodiment of the present invention, it further includes an AC power failure detection circuit delay module, which includes a diode D14, a capacitor C9, a relay U3, a resistor R44, and a resistor R42; the positive terminal of the diode D14 is connected to the output terminal of the transformer module, and its negative terminal is connected to the first terminal of the capacitor C9 and the relay U3 respectively. The other terminal of the capacitor C9 is grounded, and the resistors R44 and R42 are connected in series to the second terminal of the relay U3, with one terminal of the resistor R42 grounded.

[0013] According to one embodiment of the present invention, the transformer module includes a transformer A3 and a transformer control unit. The primary winding of the transformer A3 is connected to the output terminal of the filter and rectifier module. The transformer control unit includes a control chip A22, a second voltage divider assembly, and a third voltage divider assembly. The control chip A22 has a GND terminal, a CC terminal, a VDD terminal, an FB terminal, a Drain1 terminal, a Drain2 terminal, a Drain3 terminal, and a CS terminal. The GND terminal of the control chip A22 is grounded. One end of the second voltage divider assembly is connected to the secondary winding of the transformer A3, and the other end is connected to the CC terminal and the VDD terminal of the control chip A22, respectively. The VDD terminal is also connected to the output terminal of the filter and rectifier module. The FB terminal of the control chip A22 is connected to the fourth terminal of the optocoupler A16, and the third terminal of the optocoupler A16 is grounded. One end of the third voltage divider assembly is connected to the CS terminal of the control chip A22, and the other end is grounded. The Drain1, Drain2, and Drain3 terminals of the control chip A22 are all connected to the primary winding of the transformer A3.

[0014] According to one embodiment of the present invention, the filter output module includes a diode A23, a first filter unit and a resistor R18. The input terminal of the diode A23 is connected to the output terminal of the transformer module, and the output terminal of the diode A23 is connected to the input terminal of the first filter unit. The first filter unit is connected to the low-voltage alarm module and the battery power supply module respectively.

[0015] According to one embodiment of this utility model, the filtering and rectifying module includes a fuse F1, a varistor A5, a second filtering unit, and a rectifier bridge BD1. One end of the fuse F1 is connected to the live wire L, and the other end is connected to one end of the varistor A5. The varistor A5 is connected in parallel between the live wire L and the neutral wire N. The second filtering unit includes Y capacitors CY1 and CY2, X capacitors CX1 and CX2, resistors RX1 and RX2, and a common-mode inductor A14. Capacitor CX1 is connected in parallel with the varistor A5, and resistors RX1 and RX2 are connected in series. RX1 and resistor RX2 are connected in parallel with capacitor CX1. Y capacitors CY2 and CY1 are connected in parallel between the ground wire and the neutral wire N. The first terminal of common mode inductor A14 is connected to resistor RX2, the second terminal of common mode inductor A14 is connected to resistor RX1, the third terminal of common mode inductor A14 is connected to the first terminal of rectifier bridge BD1, the fourth terminal of common mode inductor A14 is connected to the third terminal of rectifier bridge BD1, X capacitor CX2 is connected in parallel between the first and third terminals of rectifier bridge BD1, the fourth terminal of rectifier bridge BD1 is grounded, and the second terminal of rectifier bridge BD1 is connected to the input terminal of the transformer module.

[0016] The beneficial effects of this utility model are as follows: the filtering and rectifying module receives AC mains power and filters and rectifies it, converting it into DC output. The DC output from the filtering and rectifying module enters the transformer module, which steps down the DC output and then outputs it to the input of the filtering output module. The filtering output module receives the DC output from the transformer module, filters it, and outputs a stable electrical signal to power the equipment. In this embodiment, the output of the filtering output module outputs a +13.8V / 5A electrical signal. The battery power supply module stores electrical energy and discharges when the AC mains power is interrupted, ensuring the switching power supply control circuit continuously outputs a stable electrical signal to continue powering the equipment. The Zener diode ZD1 in the low-voltage alarm module changes its on / off state by detecting the output voltage of the battery-powered module. The on / off state of ZD1 controls the on / off state of the optocoupler U2 and transistor Q1, thereby controlling the LED4 to light up or turn off. When the output voltage of the battery-powered module falls below a preset value, the LED lights up to alert the user of the voltage drop, allowing for timely intervention and preventing over-discharge of the battery. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1This is a circuit block diagram of the low-voltage alarm switching power supply control circuit in the embodiment;

[0019] Figure 2 This is a circuit diagram of the downstream section of the transformer module in the embodiment;

[0020] Figure 3 This is a circuit diagram of the front-end section of the transformer module in the embodiment.

[0021] Explanation of reference numerals in the attached figures

[0022] 1. Filtering and rectifying module; 11. Second filtering unit; 2. Transformer module; 21. Transformer control unit; 211. Second voltage divider assembly; 212. Third voltage divider assembly; 3. Filtering output module; 31. First filtering unit; 4. Battery power supply module; 41. Detection and control assembly; 411. Battery control unit; 412. First voltage divider assembly; 42. Power supply assembly; 5. Low voltage alarm module; 6. Sampling feedback module; 61. First voltage regulator assembly; 7. AC power failure detection circuit delay module. Detailed Implementation

[0023] The following drawings will disclose several embodiments of this utility model. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details should not be used to limit this utility model. That is, in some embodiments of this utility model, these practical details are not essential. In addition, for the sake of simplicity, some conventional structures and components will be shown in the drawings in a simple schematic manner.

[0024] Furthermore, in this utility model, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the utility model. They are merely used to distinguish components or operations described with the same technical terms and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0025] Please refer to Figures 1-2 , Figure 1 This is a circuit block diagram of the low-voltage alarm switching power supply control circuit. Figure 2The circuit diagram of the downstream section of the transformer module. This embodiment provides a switching power supply control circuit, which includes a filter and rectifier module 1, a transformer module 2, a filter output module 3, and a low-voltage alarm module 5. The input terminal of the filter and rectifier module 1 is connected to the AC mains power supply, and the output terminal of the filter and rectifier module 1 is connected to the input terminal of the transformer module 2. The output terminal of the transformer module 2 is connected to the input terminal of the filter output module 3, and the output terminal of the filter output module 3 outputs a stable electrical signal to power the electrical equipment. The battery power supply module 4 is connected to both the filter output module 3 and the low-voltage alarm module 5.

[0026] The filter and rectifier module 1 receives AC mains power and filters and rectifies it to convert it into DC output. The DC output from the filter and rectifier module 1 enters the transformer module 2, which steps down the DC output before outputting it to the input of the filter output module 3. The filter output module 3 receives the DC output from the transformer module 2, filters it, and outputs a stable electrical signal to power the equipment. In this embodiment, the output of the filter output module 3 is a +13.8V / 5A signal. The battery power module 4 stores electrical energy and discharges when the AC mains power is interrupted, ensuring the switching power supply control circuit continuously outputs a stable electrical signal to power the equipment. The low-voltage alarm module 5 detects the voltage of the battery power module 4. When the voltage of the battery power module 4 is too low, the low-voltage alarm module 5 sounds an alarm to alert the user.

[0027] Specifically, the low-voltage alarm module 5 includes diode D9, resistor A7, optocoupler U2, Zener diode ZD1, transistor Q1, transistor A26, resistors R10 and R27, and LED4. During connection, the anode of diode D9 is connected to the output terminal of the filter output module 3, and the cathode of diode D9 is connected in series with resistor R7. The other end of resistor R7 is connected to the emitters of transistor Q1 and transistor A26, respectively. Optocoupler U2 has a first terminal, a second terminal, a third terminal, and a fourth terminal. The second terminal of optocoupler U2 is connected to the output terminal of transformer module 2, and the first terminal of optocoupler U2 is connected to the anode of Zener diode ZD1. The cathode of Zener diode ZD1 is connected to resistor A7, battery power supply module 4, the emitter of transistor Q1, and the fourth terminal of optocoupler U2, respectively. The collector of transistor Q1 and the third terminal of optocoupler U2 are both grounded. The base of transistor Q1 is connected to the collectors of resistor A7 and transistor A26, respectively; one end of resistor R10 is connected to the output terminal of filter output module 3, and the other end is connected to the base of transistor A26. One end of resistor R27 is connected to the collector of transistor A26, and the other end is connected to the positive terminal of LED4, with the negative terminal of LED4 grounded.

[0028] In practical applications, when the switching power supply control circuit continuously outputs a stable rated power supply, the negative voltage of the Zener diode ZD1 is high. Zener diode ZD1 reverse-biased and conducts, energizing the first terminal of optocoupler U2. Optocoupler U2 remains conducting, thus maintaining current output at the third terminal. This keeps the collector of transistor Q1 high, while transistor Q1 remains cut off, and the base of transistor Q1 low. At this time, LED4 remains cut off and does not light up. It should be noted that in this example, transistor Q1 is a PNP transistor.

[0029] When the AC mains power is interrupted, the filter output module 3 has no output. When the battery power supply module 4 detects the lack of output from the filter output module, it turns on and discharges. The discharge signal of the battery power supply module 4 is output from the output terminal of the filter output module 3. As the battery power supply module 4 outputs, the stored energy decreases, causing its voltage to drop. When the voltage of the battery power supply module 4 falls below a preset voltage value, the negative voltage of the Zener diode ZD1 also falls below the preset voltage value. Zener diode ZD1 exits its breakdown state and is cut off. At this time, no current flows through the first terminal of the optocoupler U2, causing it to stop working, and thus no current flows through its third pin. At this time, the emitter of transistor Q1 is at a low level, causing it to conduct. After Q1 conducts, its base is at a high level. The high-level signal, after being current-limited by resistor R27, enters the LED4, causing it to turn on and illuminate, thus informing the user that the voltage of the battery power supply module 4 is low. In this embodiment, the preset voltage value is set to 11V, that is, when the voltage received by the negative terminal of Zener diode ZD1 is less than or equal to 11V, Zener diode ZD1 is turned off.

[0030] Thus, by controlling the on / off state of the Zener diode ZD1 using the output voltage of the battery power supply module 4, and using the on / off state of the Zener diode ZD1 to control the on / off state of the optocoupler U2 and the transistor Q1, the LED4 is controlled to turn on or off. When the output voltage of the battery power supply module 4 is lower than a preset value, the LED lights up to alert the user that the voltage of the battery power supply module 4 has dropped, allowing the user to take timely action and prevent the battery power supply module 4 from being over-discharged.

[0031] Please refer to Figure 2Furthermore, the low-voltage alarm module 5 also includes a fuse F2, a resistor R10, a diode D15, a resistor R24, a resistor R28, a transistor Q2, and a relay U1. Fuse F2 is connected to the filter output module 3. The anode of diode D9 is connected to one end of fuse F2, and the other end of fuse F2 serves as the output terminal of the filter output module 3, outputting a +13.8V / 5A electrical signal. The base of transistor A26 is connected in series with one end of resistor R10, and the other end of resistor R10 is connected to the output terminal of fuse F2. The anode of diode D15 is connected to the collector of transistor A26 and resistor R27, and the cathode of diode D15 is connected to resistor R24 ​​and the base of transistor Q2. The emitter of transistor Q2 is connected in series with resistor R28 and then to the emitter of transistor A26. The collector of transistor Q2 is connected to relay U1.

[0032] Fuse F2 is used in the protection circuit for abnormal power supply of the filter output module 3. Specifically, when the power supply of the filter output module 3 is abnormal, fuse F2 overheats and trips, preventing the filter output module 3 from continuously outputting and burning out the electrical equipment. When fuse F2 trips, the electrical signal output by the filter output module 3 cannot pass through fuse F2. The electrical signal output by the filter output module 3 is rectified by diode D9, current-limited by resistor A7, and then output to the emitter of transistor A26, where the emitter of transistor A26 is at a high level. Because fuse F2 is tripped, no electrical signal is input to the base of transistor A26 through resistor R10 at the output terminal of the filter output module 3, making the base of transistor A26 low, thus turning on transistor A26. After transistor A26 turns on, LED4 is energized and illuminates, and simultaneously, diode D15 turns on. After diode D15 turns on, the base of transistor Q2 is low. Since the emitter of transistor A26 is at a high level, the emitter of transistor Q2 is also at a high level, causing transistor Q2 to conduct. The collector of transistor Q2 outputs current to relay U1, energizing and closing relay U1. In this example, relay U1 is a normally open relay, with a first, second, third, and fourth terminal. The first terminal of relay U1 is connected to the collector of transistor Q1, and the second terminal of relay U1 is grounded through resistor R11. The third and fourth terminals of relay U1 are used to connect to the power grid in actual use. The change in the open / closed state of the third and fourth terminals of relay U1 indicates a circuit fault to the user. It should be noted that when the voltage of battery power module 4 is lower than the preset voltage value, Zener diode ZD1 is cut off, optocoupler U2 is cut off, causing transistor Q1 to conduct, which in turn causes transistor A26 to conduct, thereby turning on diode D15 and LED4. When diode D15 is turned on, transistor Q1 is turned on, thereby closing relay U1.

[0033] Please refer to Figure 2 The low-voltage alarm module 5 also includes a resistor R45, a transistor A12, and a resistor R8. One end of resistor R45 is connected to resistor A7, and the other end of resistor R45 is connected to the emitter of transistor A12. The collector of transistor A12 is connected to one end of resistor R8, and the other end of resistor R8 is connected to the battery power supply module 4. The emitter of transistor A12 is connected to the base of transistor Q1 and resistor R27.

[0034] In actual use, the current output from filter module 3 passes through diode D9 and resistor A7 before being input to resistor R45. Resistor R45 limits the current of the electrical signal, and the current-limited signal is input to the emitter of transistor A12. The base of transistor A12 is connected to battery power module 4. When the voltage of battery power module 4 is too low, the base of transistor A12 is at a low level, causing transistor A12 to conduct. At this time, the collector of transistor A12 is at a high level, causing LED4 to conduct and light up, thus indicating that the voltage of battery power module 4 is too low. In this example, when the voltage of battery power module 4 is lower than 8V, the base of transistor A12 is at a low level.

[0035] Please refer to Figure 2 The switching power supply control circuit in this example also includes a sampling feedback module 6. The sampling feedback module 6 includes a first voltage regulator component 61 and an optocoupler A16. The first voltage regulator component 61 is connected to the filter output module 3 and the optocoupler A16. The optocoupler A16 has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the optocoupler A16 is connected to the filter output module 3, the second terminal of the optocoupler A16 is connected to the first voltage regulator component 61, and the third and fourth terminals of the optocoupler A16 are connected to the transformer module 2.

[0036] When the AC mains power supply is normal, the filter output module 3 continuously outputs an electrical signal. The first voltage regulator component 61 receives the electrical signal output by the filter output module 3, samples it, and regulates its voltage. Then, the regulated electrical signal is input, isolated by optocoupler A16, and output to the transformer module 2. The transformer module 2 receives the electrical signal output by optocoupler A16 and adjusts its output according to the signal output by optocoupler A16, so that the transformer module 2 maintains a constant output through feedback.

[0037] In this example, the first voltage regulator component 61 includes resistors R14 and R13, capacitor C19, resistor R12, voltage regulator A17, and resistor R9. One end of resistor R14 is connected to the filter output module 3, and its other end is connected in series with resistor R13. The other end of resistor R13 is connected to capacitor C19, the R terminal of voltage regulator A17, and resistor R9, respectively. The other end of capacitor C19 is connected in series with resistor R12, and the other end of resistor R12 is connected to the second terminal of optocoupler A16 and the K terminal of voltage regulator A17, respectively. The A terminal of voltage regulator A17 and the other end of resistor R9 are connected to ground. Resistor R14 is used for sampling, and resistor R13 is used for current limiting. Capacitor C19 and resistor R12 form an RC circuit, which is used for filtering. Voltage regulator A17 is used to regulate the voltage of the electrical signal.

[0038] Please refer to Figure 2 Furthermore, the battery-powered module 4 includes a detection and control component 41 and a power supply component 42. The input terminal of the detection and control component 41 is connected to the filter output module 3, and its output terminal is connected to the power supply component 42. The detection and control component 41 is used to detect the electrical signal output by the filter output module 3 and control the power supply component 42 according to the electrical signal output by the filter output module 3. According to the control of the detection and control component 41, when the filter output module 3 has no output, the power supply component 42 maintains the output of the switching power supply control circuit by discharging itself.

[0039] Specifically, the power supply component 42 includes diode D10, fuse F3, battery BT, relay A4, resistor R23, resistor R1, light-emitting diode LED1, diode D7, and diode D6. The positive terminal of diode D10 is connected to the filter output module 3, and the negative terminal of diode D10 is connected to fuse F3 and resistor A7. The other end of fuse F3 is connected to the first terminal of relay A4 and the emitter of transistor Q1. Relay A4 has a first terminal, a second terminal, and a third terminal. The negative terminal of battery BT is grounded, and the positive terminal of battery BT is connected to the low-voltage alarm module 5, the first terminal of relay A4, the emitter of transistor Q1, and one end of resistor R23. The other end of resistor R23 is connected to the output terminal of transformer module 2. One end of resistor R1 is connected to the first terminal of relay A4, the positive terminal of battery BT, and resistor R23, and the other end is connected to the positive terminal of light-emitting diode LED1. The negative terminal of light-emitting diode LED1 is connected to the second terminal of relay A4, the positive terminal of diode D7, and the output terminal of detection and control component 41. The cathode of diode D7 is connected to the anode of battery BT, resistor R23, and the emitter of transistor Q1. The anode of diode D6 is connected to the third terminal of the relay, and the cathode of diode D6 is connected to the output terminal of filter output module 3.

[0040] In actual use, the input terminal of the detection control component 41 receives the electrical signal output from the filter output module 3, and then the detection control component 41 determines whether the output voltage of the filter output module 3 is normal. When the filter output module 3 is outputting normally, the output terminal of the detection control component 41 outputs an electrical signal to power relay A4, keeping relay A4 in a normally open state. At the same time, the electrical signal output from the filter output module 3 passes through diode D9 and resistor A7, and then through fuse F3 before being input to the positive terminal of battery BT to charge battery BT. At this time, since relay A4 is in a normally open state, the path of LED1 cannot be closed, and LED1 is in an off state. When the filter output module 3 has no output, the output terminal of the detection control component 41 has no electrical signal output. At this time, relay A4 is de-energized and closed, providing a current path for LED1, causing LED1 to light up, thereby warning the user that the AC power is cut off. It should be noted that LED1 and LED4 have different light colors to distinguish different situations. In this example, LED1 is yellow and LED4 is red. After relay A4 is closed, battery BT discharges. The discharge current of battery BT passes through relay A4, and then through diode D6 to be output to filter output module 3 to maintain the stable output of filter output module 3.

[0041] Please refer to Figure 2 Furthermore, the detection control component 41 includes a comparator A24, a battery control unit 411, a first voltage divider component 412, and a voltage regulator A6. The comparator A24 has a VCC terminal, a GND terminal, a first connection terminal, a second connection terminal, a third connection terminal, and a fourth connection terminal. The VCC terminal of the comparator A24 is connected to the filter output module 3. One end of the first voltage divider component 412 is connected to the VCC terminal of the comparator A24, and the other end is grounded. The second and third terminals of the comparator A24 are respectively connected to the first voltage divider component 412, and the GND terminal of the comparator A24 is grounded. The battery control unit 411 has terminals 1-3. Terminal 1 of the battery control unit 411 is connected to the positive terminal of diode D7 and the second terminal of relay A4; terminal 2 of the battery control unit 411 is connected to the first connection terminal of the comparator A24; and terminal 3 of the battery control unit 411 is grounded. The voltage regulator A6 has a K terminal, an R terminal and an A terminal. The K terminal of the voltage regulator A6 is connected to the second connection terminal of the comparator A24, the R terminal of the voltage regulator A6 is connected to the first voltage divider component 412, and the A terminal of the voltage regulator A6 is grounded.

[0042] In actual use, the electrical signal output from the filter output module 3 is supplied to the VCC terminal of comparator A24 to power comparator A24, enabling it to operate. Simultaneously, the power output from the filter output module 3 is divided by the first voltage divider component 412 and then input to the second and third connection terminals of comparator A24. Voltage regulator A6 regulates the electrical signal input to the second connection terminal of comparator A24, ensuring a stable electrical signal output. Comparator A24 determines whether the filter output module 3 is outputting a normal electrical signal (i.e., whether the AC mains power supply is interrupted) based on the electrical signals input to its first and second connection terminals. When the AC mains power supply is normal, the filter output module 3 outputs normally. The voltage of the electrical signal input to the second connection terminal of comparator A24 is lower than the voltage of the electrical signal input to the third connection terminal. At this time, the first connection terminal of comparator A24 outputs a low-level signal, causing the battery control unit 411 to conduct. Then, the electrical signal output from the first connection terminal of comparator A24 passes through the battery control unit 411 and supplies power to the battery power supply module 4. When the AC mains power supply is interrupted or malfunctions, the output voltage of the filter output module 3 gradually decreases. Since the electrical signal input to the second connection terminal of comparator A24 is regulated by voltage regulator A6, the voltage of the electrical signal input to the second connection terminal of comparator A24 is higher than the voltage of the electrical signal input to the third connection terminal. The first connection terminal of comparator A24 outputs a high-level signal, causing the battery control unit 411 to turn off.

[0043] Please refer to Figure 2Specifically, the battery control unit 411 includes a resistor R22, a transistor A20, and a diode D1. In this example, transistor A20 is an NPN transistor. One end of resistor R22 is connected to the first terminal of comparator A24. The end of resistor R22 connected to comparator A24 is terminal 2 of the battery control unit 411. The other end of resistor R22 is connected to the collector of transistor A20. The emitter of transistor A20 is grounded, serving as terminal 3 of the battery control unit 411. The collector of transistor A20 is connected to the cathode of diode D1. The anode of diode D1 is connected to diode D7 and the second terminal of relay A4. The anode of diode D1 serves as terminal 1 of the battery control unit 411. When the AC mains power supply is normal, the first terminal of comparator A24 outputs a low-level signal. The high-level signal, after being current-limited by resistor R22, is input to the collector of transistor A20, at which point transistor A20 is turned on. The base of transistor A20 outputs an electrical signal, which, after passing through diode D1, powers relay A4, keeping it normally open. When the AC power supply is interrupted, the first terminal of comparator A24 outputs a high-level signal, while a low-level signal is input to the collector of transistor A20. Transistor A20 cannot conduct, and therefore, no current flows through relay A4, causing it to close. This process controls the switching state of relay A4.

[0044] Please refer to Figure 2 Furthermore, the first voltage divider assembly 412 includes resistors R17, R15, R21, R19, and R16. One end of resistor R17 is connected to the filter output module 3 and the VCC terminal of comparator A24, respectively, and its other end is connected in series with resistor R15 and then grounded. The third connection terminal of comparator A24 is connected to resistors R17 and R15. One end of resistor R21 is connected to resistor R17 and the VCC terminal of comparator A24, respectively, and its other end is connected in series with resistors R19 and R16 and then grounded. The second connection terminal of comparator A24 is connected to resistors R21 and R19. The R terminal of voltage regulator A6 is connected to resistors R19 and R16.

[0045] Please refer to Figure 2 The switching power supply control circuit in this embodiment also includes an AC power failure detection circuit delay module 7, which includes a diode D14, a capacitor C9, a relay U3, and resistors R44 and R42. Relay U3 has a first terminal, a second terminal, a third terminal, and a fourth terminal. The anode of diode D14 is connected to the output terminal of transformer module 2, and the cathode of diode D14 is connected to both capacitor C9 and the first terminal of relay U3. The other terminal of capacitor C9 is grounded. Resistors R44 and R42 are connected in series to the second terminal of relay U3, and one end of resistor R42 is grounded. The third and fourth terminals of relay U3 are connected to the power grid.

[0046] When the AC mains power supply is normal, transformer module 2 outputs a stable signal. The electrical signal output from transformer module 2 passes through diode D14 and is input to the first terminal of relay U3 and capacitor C9, causing the first and second terminals of relay U3 to conduct, keeping relay U3 in a normally closed state. Simultaneously, the electrical signal charges capacitor C9. When the AC mains power supply fails or is interrupted, transformer module 2 has no output. At this time, capacitor C9 begins to discharge, maintaining power supply to the first terminal of relay U3. If the charge stored in capacitor C9 is completely released and the AC mains power supply has not been restored, relay U3 disconnects. At this time, the third and fourth terminals of relay U3 are open-circuited, alerting the user to the AC mains power outage. By setting up the AC power failure detection circuit delay module 7, the power supply time is extended by discharging capacitor C9 after an AC mains power failure or interruption.

[0047] Please refer to Figure 3 , Figure 3 This is a circuit diagram of the front-end section of the transformer module. The transformer module 2 includes a transformer A3 and a transformer control unit 21. The primary winding of transformer A3 is connected to the output terminal of the filter and rectifier module 1 to receive the electrical signal output by the filter and rectifier module 1 and step down the voltage of the signal. Specifically, the transformer control unit 21 includes a control chip A22, a second voltage divider component 211, and a third voltage divider component 212. The control chip A22 has GND, CC, VDD, FB, Drain1, Drain2, Drain3, and CS terminals, with the GND terminal of the control chip A22 grounded. One end of the second voltage divider component 211 is connected to the secondary winding of transformer A3, and the other end is connected to the CC and VDD terminals of the control chip A22. The VDD terminal is also connected to the output terminal of the filter and rectifier module 1. The FB terminal of the control chip A22 is connected to the fourth terminal of optocoupler A16, and the third terminal of optocoupler A16 is grounded. One end of the third voltage divider component 212 is connected to the CS terminal of the control chip A22, and the other end is grounded. The Drain1, Drain2, and Drain3 terminals of the control chip A22 are all connected to the primary winding of the transformer.

[0048] Control chip A22 controls the output of transformer A3 based on the electrical signal output from transformer A3. Specifically, the electrical signal output from filter and rectifier module 1 is input to the primary winding of transformer A3 and the VDD terminal of control chip A22, energizing control chip A22. The first and second terminals of optocoupler A16 receive the electrical signal from filter output module 3, and after isolation by optocoupler A16, the signal is input to the FB terminal of control chip A22. The FB terminal of control chip A22 receives the electrical signal output from optocoupler A16 and controls transformer A3 based on the feedback signal from the FB terminal, ensuring that transformer A3 maintains its rated voltage output.

[0049] Furthermore, the second voltage divider component 211 includes a diode D11, a resistor R36, and a resistor R37. The anode of diode D11 is connected to the secondary winding of transformer A3. One end of resistor R36 is connected to the cathode of diode D11, and the other end is connected to the VDD terminal of control chip A22 and resistor R37. The other end of resistor R37 is connected to the CC terminal of control chip A22. The electrical signal output from the secondary winding of transformer A3 is rectified and filtered by diode D11, then divided by resistor R36, and then input to the VDD terminal of control chip A22 and resistor R27 respectively. After being divided by resistor R27, it is input to the CC terminal of control chip A22 to power control chip A22.

[0050] The second voltage divider unit includes resistors R33, R32, R31, R32A, and R32B. Resistors R33, R32, R31, R32A, and R32B are connected in parallel to the CS terminal of the control chip A22 to protect the CS terminal of the control chip A22.

[0051] The filter output module 3 includes a diode A23, a first filter unit 31, and a resistor R18. The input terminal of the diode A23 is connected to the output terminal of the transformer module 2, and the output terminal of the diode A23 is connected to the input terminal of the first filter unit 31. The first filter unit 31 is connected to the low-voltage alarm module 5 and the battery power supply module 4, and the output terminal of the first filter unit 31 outputs a stable electrical signal to power the electrical equipment.

[0052] In this example, diode A23 is used to receive and rectify the electrical signal output from transformer module 2. The rectified signal is then output to the first filter unit 31 and filtered. The first filter unit 31 includes capacitors C7 and C8, a differential-mode inductor R41, and capacitor C1. Capacitors C7, C8, and C1 are connected in parallel to the output terminal of the transient voltage suppression diode, and the differential-mode inductor R41 is connected in series between capacitors C8 and C1. Capacitors C7, C8, and C1 are all used for filtering, while the differential-mode inductor R41 is used to suppress interference signals, making the electrical signal output from the filter output module 3 more stable.

[0053] Please refer to Figure 3The filtering and rectifier module 1 includes a fuse F1, a varistor A5, a second filter unit 11, and a rectifier bridge BD1. One end of the fuse F1 is connected to the live wire L, and the other end is connected to the varistor A5. The fuse F1 is used to blow when the AC power supply exceeds its rated current value to protect the circuit. The varistor A5 is connected in parallel between the live wire L and the neutral wire N, and is used to prevent overvoltage of the input AC power supply. The second filter unit 11 is used to filter the input AC power supply. The second filter unit 11 includes a Y capacitor CY2, an X capacitor CX1, an X capacitor CX2, a resistor RX1, a resistor RX2, and a common-mode inductor A14. The capacitor CX1 is connected in parallel with the varistor A5. The capacitor CX1 is used to suppress differential-mode interference and provide a stable electrical signal for subsequent circuits. The resistors RX1 and RX2 are connected in series, and after being connected in series, they are connected in parallel with the capacitor CX1. The resistors RX1 and RX2 are used for voltage division. Y capacitors CY2 and CY1 are connected in parallel between the ground wire and the neutral wire N. Y capacitors CY2 and CY1 are safety capacitors used to suppress common-mode interference. Common-mode inductor A14 is connected in parallel with X capacitors CX1 and CX2. The third terminal of common-mode inductor A14 is connected to the first terminal of rectifier bridge BD1, and the fourth terminal of common-mode inductor A14 is connected to the third terminal of rectifier bridge BD1. Common-mode inductor A14 is used to suppress common-mode interference. X capacitor CX2 is connected in parallel between rectifier bridge BD1 and common-mode inductor A14, and is used to suppress differential-mode interference signals. The fourth terminal of rectifier bridge BD1 is grounded, and the second terminal of rectifier bridge BD1 is connected to the input terminal of transformer module 2. Rectifier bridge BD1 is used to receive the electrical signal filtered by the second filter unit 11 and rectify the electrical signal to form DC output to power transformer module 2.

[0054] In summary, the AC mains power supply is filtered and rectified by the filter and rectifier module 1 to form DC power. The transformer module 2 receives the DC power output from the filter and rectifier module 1 and steps it down. The filter output module 3 receives the electrical signal output from the transformer module 2 and filters and outputs it. When the AC mains power supply is interrupted, the battery power supply module 4 discharges itself to the filter and rectifier module 1 to maintain the continuous output of the switching power supply control circuit. When the voltage of the battery power supply module 4 is too low, the low-voltage alarm module 5 sounds an alarm to alert the user to take timely action and prevent the battery power supply module 4 from discharging for an extended period of time, thus protecting the battery power supply module 4.

[0055] The above description is merely an embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this utility model should be included within the scope of the claims of this utility model.

Claims

1. A low-voltage alarm switching power supply control circuit, characterized in that, include: The system comprises a filter rectifier module (1), a transformer module (2), a filter output module (3), a battery power supply module (4), and a low-voltage alarm module (5); the input terminal of the filter rectifier module (1) is connected to the AC mains power supply; the input terminal of the transformer module (2) is connected to the output terminal of the filter rectifier module (1); the input terminal of the filter output module (3) is connected to the output terminal of the transformer module (2); the battery power supply module (4) is connected to the filter output module (3) and the low-voltage alarm module (5); the low-voltage alarm module (5) includes a diode D9, a resistor A7, an optocoupler U2, a Zener diode ZD1, a transistor Q1, a transistor A26, a resistor R10, a resistor R27, and a light-emitting diode LED4; the positive terminal of the diode D9 is connected to the output terminal of the filter output module (3), the negative terminal of the diode D9 is connected in series with the resistor R7, and the other terminal of the resistor R7 is connected in series with the resistor R7. The first end of the optocoupler U2 is connected to the anode of the transistor Q1 and the anode of the transistor A26 respectively; the second end of the optocoupler U2 is connected to the output terminal of the transformer module (2); the first end of the optocoupler U2 is connected to the positive terminal of the Zener diode ZD1; its negative terminal is connected to the resistor A7, the anode of the transistor Q1, the battery power supply module (4), and the fourth end of the optocoupler U2 respectively; the collector of the transistor Q1 and the third end of the optocoupler U2 are connected to ground; the base of the transistor Q1 is connected to the collector of the resistor A7 and the collector of the transistor A26 respectively; one end of the resistor R10 is connected to the output terminal of the filter output module (3); its other end is connected to the base of the transistor A26; one end of the resistor R27 is connected to the base of the transistor Q1; its other end is connected to the anode of the light-emitting diode LED4; the negative terminal of the light-emitting diode LED4 is grounded.

2. The low-voltage alarm switching power supply control circuit according to claim 1, characterized in that, The low-voltage alarm module (5) also includes a fuse F2, a resistor R10, a diode D15, a resistor R24, a resistor R28, a transistor Q2, and a relay U1. The fuse F2 is connected to the output terminal of the filter and rectifier module (1). One end of the resistor R10 is connected to the other end of the fuse F2. The other end of the resistor R10 is connected to the base of the transistor A26. The positive terminal of the diode D15 is connected to the collector of the transistor A26 and the resistor R27. The negative terminal of the diode D15 is connected to the resistor R24 ​​and the base of the transistor Q2. One end of the resistor R28 is connected to the emitter of the transistor A26, and the other end is connected to the emitter of the transistor Q2. The collector of the transistor Q2 is connected to the relay U1.

3. The low-voltage alarm switching power supply control circuit according to claim 1, characterized in that, The low-voltage alarm module (5) also includes a resistor R45, a transistor A12 and a resistor R8; one end of the resistor R45 is connected to the resistor A7, and the other end is connected to the emitter of the transistor A12. The collector of the transistor A12 is connected to one end of the resistor R8, and the other end of the resistor R8 is connected to the battery power supply module (4); the collector of the transistor A12 is connected to the base of the transistor Q1 and the resistor R27.

4. The low-voltage alarm switching power supply control circuit according to claim 1, characterized in that, It also includes a sampling feedback module (6), which includes a first voltage regulator component (61) and an optocoupler A16; the first voltage regulator component (61) is connected to the filter output module (3) and the optocoupler A16 respectively; the first end of the optocoupler A16 is connected to the filter output module (3), the second end of the optocoupler A16 is connected to the first voltage regulator component (61), and the third and fourth ends of the optocoupler A16 are connected to the transformer module (2).

5. The low-voltage alarm switching power supply control circuit according to claim 1, characterized in that, The battery power supply module (4) includes a detection and control component (41) and a power supply component (42). The input terminal of the detection and control component (41) is connected to the filter output module (3), and its output terminal is connected to the power supply component (42). The power supply component (42) includes a diode D10, a fuse F3, a battery BT, a relay A4, a resistor R23, a resistor R1, a light-emitting diode LED1, a diode D7, and a diode D6. The positive terminal of the diode D10 is connected to the filter output module (3), and the negative terminal of the diode D10 is connected to the fuse F3 and the resistor A7. The other end of the fuse F3 is connected to the first terminal of the relay A4 and the emitter of the transistor Q1. The negative terminal of the battery BT is grounded, and the positive terminal of the battery BT is connected to the low-voltage alarm module (5) and the... The first terminal of relay A4, the emitter of transistor Q1, and one end of resistor R23 are connected. The other end of resistor R23 is connected to the output terminal of transformer module (2). One end of resistor R1 is connected to the first terminal of relay A4, the positive terminal of battery BT, and resistor R23. Its other end is connected to the positive terminal of light-emitting diode LED1. The negative terminal of light-emitting diode LED1 is connected to the second terminal of relay A4, the positive terminal of diode D7, and the output terminal of detection and control component (41). The negative terminal of diode D7 is connected to the positive terminal of battery BT, resistor R23, and emitter of transistor Q1. The positive terminal of diode D6 is connected to the third terminal of relay A4. The negative terminal of diode D6 is connected to the output terminal of filter output module (3).

6. The low-voltage alarm switching power supply control circuit according to claim 5, characterized in that, The detection and control component (41) includes a comparator A24, a battery control unit (411), a first voltage divider component (412), and a voltage regulator A6. The comparator A24 has a VCC terminal, a GND terminal, a first connection terminal, a second connection terminal, a third connection terminal, and a fourth connection terminal. The VCC terminal of the comparator A24 is connected to the filter output module (3). One end of the first voltage divider component (412) is connected to the VCC terminal of the comparator A24, and the other end is grounded. The second connection terminal and the third connection terminal of the comparator A24 are respectively connected to the first voltage divider component (412). The GND terminal of the comparator A24 is grounded; the battery control unit (411) has terminal 1, terminal 2 and terminal 3. Terminal 1 of the battery control unit (411) is connected to the positive terminal of the diode D7 and the second terminal of the relay A4. Terminal 2 of the battery control unit (411) is connected to the first connection terminal of the comparator A24. Terminal 3 of the battery control unit (411) is grounded; the K terminal of the voltage regulator A6 is connected to the second connection terminal of the comparator A24. The R terminal of the voltage regulator A6 is connected to the first voltage divider assembly (412). The A terminal of the voltage regulator A6 is grounded.

7. The low-voltage alarm switching power supply control circuit according to claim 1, characterized in that, It also includes an AC power failure detection circuit delay module (7), which includes a diode D14, a capacitor C9, a relay U3, a resistor R44 and a resistor R42; the positive terminal of the diode D14 is connected to the output terminal of the transformer module (2), and its negative terminal is connected to the first terminal of the capacitor C9 and the relay U3 respectively. The other terminal of the capacitor C9 is grounded. The resistors R44 and R42 are connected in series to the second terminal of the relay U3, and one terminal of the resistor R42 is grounded.

8. The low-voltage alarm switching power supply control circuit according to claim 4, characterized in that, The transformer module (2) includes a transformer A3 and a transformer control unit (21). The primary winding of the transformer A3 is connected to the output terminal of the filter rectifier module (1). The transformer control unit (21) includes a control chip A22, a second voltage divider component (211), and a third voltage divider component (212). The control chip A22 has a GND terminal, a CC terminal, a VDD terminal, an FB terminal, a Drain1 terminal, a Drain2 terminal, a Drain3 terminal, and a CS terminal. The GND terminal of the control chip A22 is grounded. One end of the second voltage divider component (211) is connected to the output terminal of the filter rectifier module (1). The secondary winding of transformer A3 is connected at one end to the CC terminal and the VDD terminal of control chip A22, respectively. The VDD terminal is also connected to the output terminal of the filter rectifier module (1). The FB terminal of control chip A22 is connected to the fourth terminal of optocoupler A16, and the third terminal of optocoupler A16 is grounded. One end of the third voltage divider component (212) is connected to the CS terminal of control chip A22, and the other end is grounded. The Drain1, Drain2, and Drain3 terminals of control chip A22 are all connected to the primary winding of transformer A3.

9. The low-voltage alarm switching power supply control circuit according to claim 1, characterized in that, The filter output module (3) includes a diode A23, a first filter unit (31) and a resistor R18. The input terminal of the diode A23 is connected to the output terminal of the transformer module (2), and the output terminal of the diode A23 is connected to the input terminal of the first filter unit (31). The first filter unit (31) is connected to the low-voltage alarm module (5) and the battery power supply module (4) respectively.

10. The low-voltage alarm switching power supply control circuit according to claim 1, characterized in that, The filtering and rectifying module (1) includes a fuse F1, a varistor A5, a second filtering unit (11), and a rectifier bridge BD1. One end of the fuse F1 is connected to the live wire L, and the other end is connected to one end of the varistor A5. The varistor A5 is connected in parallel between the live wire L and the neutral wire N. The second filtering unit (11) includes Y capacitors CY1 and CY2, X capacitors CX1 and CX2, resistors RX1 and RX2, and a common-mode inductor A14. The capacitor CX1 is connected in parallel with the varistor A5, and the resistors RX1 and RX2 are connected in series. The Y capacitor CY2 and the Y capacitor CY1 are connected in parallel between the ground line and the neutral line N; the first end of the common mode inductor A14 is connected to the resistor RX2, the second end of the common mode inductor A14 is connected to the resistor RX1, the third end of the common mode inductor A14 is connected to the first end of the rectifier bridge BD1, the fourth end of the common mode inductor A14 is connected to the third end of the rectifier bridge BD1, the X capacitor CX2 is connected in parallel between the first end and the third end of the rectifier bridge BD1, the fourth end of the rectifier bridge BD1 is grounded, and the second end of the rectifier bridge BD1 is connected to the input end of the transformer module (2).

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