Line voltage power failure detection circuit and detection method thereof

Abstract

The invention relates to a line voltage power failure detection circuit and a detection method thereof.The line voltage power failure detection circuit comprises a voltage transformation power supply module, a main power switch module, a power failure detection module, a first switch control module and a second switch control module, and the power output end of the voltage transformation power supply module is connected with the signal acquisition end of the power failure detection module; the signal output end of the power failure detection module is connected with the signal input end of the main power control module, the first signal output end of the main power control module is connected with the controlled end of the first switch control module, and the second signal output end of the main power control module is connected with the controlled end of the second switch control module. The main power switch module controls the first switch control module to be turned off and the second switch control module to be turned on so as to discharge a battery or a capacitor, the capacitor is prevented from being kept in a high-voltage state for a long time, and then the risk of electric shock is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of a line voltage power-off detection circuit, and in particular to a line voltage power-off detection circuit and a detection method thereof. Background Art

[0002] At present, when the AC / DC adapter is unplugged, there will indeed be a high voltage residual in the internal capacitor. This phenomenon is mainly because the capacitor inside the adapter still retains the charge after the device is powered off. These capacitors can store high voltage, especially when there is no load. After the power is turned off, the internal input capacitor of high-power appliances will still maintain a high voltage, posing a risk of electric shock. Therefore, the internal input capacitor must be safely discharged, but traditional charging circuits lack this function. Summary of the invention

[0003] In order to solve the problem that the traditional charging circuit lacks the ability to safely discharge the internal input capacitor, thereby posing a contact risk, the present application provides a line voltage power-off detection circuit and a detection method thereof.

[0004] A line voltage power-off detection circuit, the line voltage power-off detection circuit comprising a transformer power supply module, a main power switch module, a power-off detection module, a first switch control module, a second switch control module, a battery management module and a DC-DC module, the power input end of the transformer power supply module is connected to the mains, the power output end of the transformer power supply module is connected to the power input end of the first switch control module, the power output end of the first switch control module is connected to the power input end of the DC-DC module, the power output end of the transformer power supply module is connected to the power input end of the battery management module to supply power to the battery in the battery management module, the power output end of the battery management module is connected to the first conduction end of the second switch control module, the second conduction end of the second switch control module is connected to the DC -DC module, the power output end of the DC-DC module is used to output a stable voltage to the load for power supply, the power output end of the transformer power supply module is connected to the signal acquisition end of the power failure detection module, the signal output end of the power failure detection module is connected to the signal input end of the main power control module, the first signal output end of the main power control module is connected to the controlled end of the first switch control module, and the second signal output end of the main power control module is connected to the controlled end of the second switch control module. When the main power stops supplying power, the main power switch module controls the first switch control module to turn off and the second switch control module to turn on through the power feedback signal collected by the power failure detection module, so as to provide a low on-resistance of the battery discharge path, thereby discharging the battery or capacitor.

[0005] By adopting the above technical solution and the above line voltage power-off detection circuit, the problem of the lack of safe discharge of the internal input capacitor in the traditional charging circuit, which constitutes the risk of electric shock, can be effectively solved. When the mains power is cut off, the power-off detection module can timely collect the signal of the removal of the mains power and transmit this signal to the main power switch module. The main power switch module controls the first switch control module to close according to the detection signal, cuts off the power supply path related to the mains power in the circuit, and controls the second switch control module to open, so that the battery or capacitor in the battery management module is discharged through a low on-resistance. Through this design, the input capacitor can be quickly discharged to a safe low voltage after the mains power is disconnected, avoiding the capacitor from maintaining a high voltage state for a long time, thereby reducing the risk of electric shock and ensuring the safety of users and equipment. This automated discharge mechanism not only improves safety, but also ensures that the charge of the capacitor can be released quickly, without causing potential danger to subsequent operators.

[0006] Preferably, the power-off detection module includes a voltage acquisition network, a resistor R4, a voltage stabilizing unit and an optocoupler, the optocoupler includes a light-emitting diode OC1a and a transistor OC1b, the power output end of the transformer power supply module is connected to the first conductive end of the voltage acquisition network, the second conductive end of the voltage acquisition network is grounded, the power output end of the transformer power supply module is connected to the first end of the resistor R4, the second end of the resistor R4 is connected to the positive end of the light-emitting diode OC1a, the negative end of the light-emitting diode OC1a is connected to the first conductive end of the voltage stabilizing unit, the second conductive end of the voltage stabilizing unit is grounded, the signal output end of the voltage acquisition network is connected to the signal input end of the voltage stabilizing unit, the signal input end of the main power switch module is connected to the first conductive end of the transistor OC1b, the second conductive end of the transistor OC1b is grounded, and the voltage stabilizing unit controls the current conductive amount of the transistor OC1b by adjusting the current conductive amount of the light-emitting diode OC1a, thereby enabling the main power switch module to obtain the corresponding signal change.

[0007] By adopting the above technical solution, the optocoupler of the power failure detection module controls the current conduction of the light-emitting diode OC1a and the transistor OC1b, so that the main power switch module can obtain accurate power failure signal feedback, thereby accurately controlling the on or off state of the first switch control module and the second switch control module. This design improves the accuracy and response speed of power failure detection, ensuring that the system can switch to the backup power supply in time when the mains power fails.

[0008] Preferably, the voltage acquisition network includes a resistor R2 and a resistor R3, the power output end of the transformer power supply module is connected to the first end of the resistor R2, the second end of the resistor R2 is connected to the first end of the resistor R3, the second end of the resistor R3 is grounded, and the common node between the resistor R2 and the resistor R3 is connected to the signal input end of the voltage stabilizing unit.

[0009] By adopting the above technical solution, through the voltage-dividing design of resistors R2 and R3 in the voltage acquisition network, the change of the mains voltage can be effectively detected, and the input signal can be adjusted by the voltage stabilizing unit so that the main power switch module can receive the voltage change information in time, thereby realizing accurate monitoring of mains power failure and improving the voltage detection sensitivity and response efficiency of the entire system.

[0010] Preferably, the power-off detection module also includes a capacitor C2, a common node between the resistor R2 and the resistor R3 is connected to the first end of the capacitor C2, and a common node between the negative terminal of the light-emitting diode OC1a and the voltage stabilizing unit is connected to the second end of the capacitor C2.

[0011] By adopting the above technical solution, by adding capacitor C2 to the voltage acquisition network, the instantaneous interference signal in the mains voltage can be further filtered out to ensure a more stable voltage detection process. The addition of capacitor C2 not only improves the detection accuracy, but also effectively prevents false operation caused by voltage fluctuations, thereby improving the overall reliability of the system.

[0012] Preferably, the voltage stabilizing unit includes at least one voltage stabilizer, and the model of the voltage stabilizer is TL431.

[0013] By adopting the above technical solution, the voltage stabilization unit can accurately control the input voltage signal by using the TL431 voltage regulator to ensure that the main power switch module receives a stable voltage feedback signal. The TL431 voltage regulator has high-precision voltage stabilization characteristics, making the voltage detection of the entire power failure detection module more stable and reliable, thereby improving the response accuracy of the system when the mains power fails.

[0014] Preferably, the main power switch module includes a control chip U1, and the first switch control module includes a MOS tube M1 and a resistor R CS The first conducting end of the MOS tube M1 is connected to the power output end of the transformer power supply module, and the second conducting end of the MOS tube M1 is connected to the resistor R CS The first end of the resistor R CS The second end of is grounded, the signal input end of the control chip U1 is connected to the signal output end of the power-off detection module, and the signal output end of the control chip U1 is connected to the controlled end of the MOS tube M1.

[0015] By adopting the above technical solution, the main power switch module can quickly turn off or turn on the first switch control module when the power failure detection module sends a signal through the coordinated work of the control chip U1 and the MOS tube M1. The MOS tube M1 ensures the rapidity and stability of power switching when the mains power fails by accurately controlling the conduction state, avoiding the problem of unstable power supply of the system caused by switching delay.

[0016] Preferably, the battery management module includes a battery and a battery charging control unit, the power input end of the battery charging control unit is connected to the power output end of the transformer power supply module, the power output end of the battery charging control unit is connected to the power input end of the battery, the power output end of the battery is connected to the power input end of the second switch control module, and the signal input end of the battery charging control unit is connected to the signal output end of the main power control module.

[0017] By adopting the above technical solution, the battery management module can effectively charge the battery when the mains power is normally supplied through the cooperation of the battery and the battery charging control unit, and quickly switch to battery power supply when the mains power is cut off. This not only ensures that the battery has sufficient power in the standby state, but also can respond quickly when the mains power is cut off, realizing a stable and uninterrupted power supply function.

[0018] Preferably, the transformer power supply module includes a transformer T1 and a clamping circuit, the transformer T1 includes a primary winding Lp and a secondary winding Ls, the first end of the primary winding Lp is connected to the AC power, the common node between the second end of the primary winding Lp and the first end of the clamping circuit is connected to the power input end of the first switch control module, the second end of the clamping circuit is connected to the first end of the primary winding Lp, and the power output end of the secondary winding Ls is connected to the signal acquisition end of the power-off detection module.

[0019] By adopting the above technical solution, the transformer power supply module can effectively convert the mains voltage into the required power supply voltage through the design of transformer T1 and the clamping circuit, and prevent the mains voltage fluctuation or abnormality from causing damage to other modules of the system through the protection of the clamping circuit, thereby ensuring the stability and safety of the power supply.

[0020] Preferably, the clamping circuit includes a diode D1, a resistor R1 and a capacitor C1, the positive terminal of the diode D1 is connected to the second end of the primary winding Lp, the negative terminal of the diode D1 is connected to the first end of the resistor R1, the second end of the resistor R1 is connected to the first end of the primary winding Lp, the negative terminal of the diode D1 is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is connected to the first end of the primary winding Lp.

[0021] By adopting the above technical solution, the synergistic effect of the diode D1, resistor R1 and capacitor C1 in the clamping circuit can effectively clamp the voltage during the mains power supply process to prevent the instantaneous overshoot or fluctuation of the mains voltage from affecting the normal operation of the system. At the same time, the addition of capacitor C1 can further stabilize the voltage and ensure the stability and reliability of the system power supply.

[0022] A detection method for a line voltage power-off detection circuit is applied to a line voltage power-off detection circuit, and the detection method comprises: Obtain the minimum power supply voltage value required for charging and the input power supply voltage value; Comparing the minimum power supply voltage value required for charging with the input power supply voltage value; If the input power supply voltage value is greater than the minimum power supply voltage value required for charging, the first switch control module is controlled to be turned on so that the mains power supplies power to the DC-DC module and charges the battery in the battery management module; If the input power supply voltage value is less than the minimum power supply voltage value required for charging, the first switch control module is controlled to be disconnected and the second switch control module is controlled to be connected, so that the battery supplies power to the DC-DC module and stops charging the battery in the battery management module.

[0023] By adopting the above technical solution, when the input power supply voltage value is greater than the minimum power supply voltage value required for charging, the system is turned on through the first switch control module to ensure that the mains power supplies and charges the DC-DC module and the battery at the same time; when the input power supply voltage value is lower than the required voltage value, the system automatically switches to battery power supply to ensure that the system can continuously provide stable voltage to the load when the mains power is off. This power management method improves the reliability of the system and avoids equipment operation interruption caused by unstable power supply.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: 1. By adopting the above-mentioned line voltage power-off detection circuit, the problem of the lack of safe discharge of the internal input capacitor in the traditional charging circuit, which poses a risk of electric shock, can be effectively solved. When the AC power is cut off, the power-off detection module can promptly collect the signal of the removal of the AC power and transmit this signal to the main power switch module. The main power switch module controls the first switch control module to turn off according to the detection signal, cuts off the power supply path related to the AC power in the circuit, and controls the second switch control module to turn on, so that the battery or capacitor in the battery management module is discharged through a low on-resistance. Through this design, the input capacitor can be quickly discharged to a safe low voltage after the AC power is disconnected, avoiding the capacitor from maintaining a high voltage state for a long time, thereby reducing the risk of electric shock and ensuring the safety of users and equipment. This automated discharge mechanism not only improves safety, but also ensures that the charge of the capacitor can be released quickly, without causing potential danger to subsequent operators; 2. When the input power voltage is greater than the minimum power supply voltage required for charging, the system turns on the first switch control module to ensure that the mains power supplies and charges the DC-DC module and the battery at the same time; when the input power voltage is lower than the required voltage, the system automatically switches to battery power to ensure that the system can continuously provide stable voltage to the load when the mains power is off. This power management method improves the reliability of the system and avoids equipment operation interruptions caused by unstable power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of a line voltage power failure detection circuit in an embodiment of the present application.

[0026] Figure 2 This is a partial circuit diagram of a line voltage power-off detection circuit in one embodiment of the present application; Figure 3 This is an AC RM waveform diagram associated with a line voltage power failure detection circuit in an embodiment of the present application.

[0027] Explanation of the accompanying drawings: 1. Transformer power supply module; 2. Main power switch module; 3. Power-off detection module; 31. Voltage acquisition network; 32. Voltage stabilizing unit; 4. First switch control module; 5. Second switch control module; 6. Battery management module; 7. DC-DC module. DETAILED DESCRIPTION

[0028] The present application is further described in detail below in conjunction with the accompanying drawings.

[0029] Specifically, Figure 1As shown, a line voltage power-off detection circuit comprises a transformer power supply module 1, a main power switch module 2, a power-off detection module 3, a first switch control module 4, a second switch control module 5, a battery management module 6 and a DC-DC module 7, wherein the power input end of the transformer power supply module 1 is connected to the mains, the power output end of the transformer power supply module 1 is connected to the power input end of the first switch control module 4, the power output end of the first switch control module 4 is connected to the power input end of the DC-DC module 7, the power output end of the transformer power supply module 1 is connected to the power input end of the battery management module 6 to supply power to the battery in the battery management module 6, the power output end of the battery management module 6 is connected to the first conduction end of the second switch control module 5, and the second conduction end of the second switch control module 5 is connected to the power input end of the DC-DC module 7. The power supply output end of the transformer power supply module 1 is connected to the power input end of the DC-DC module 7, and the power output end of the DC-DC module 7 is used to output a stable voltage to the load for power supply. The power output end of the transformer power supply module 1 is connected to the signal acquisition end of the power failure detection module 3, and the signal output end of the power failure detection module 3 is connected to the signal input end of the main power control module. The first signal output end of the main power control module is connected to the controlled end of the first switch control module 4, and the second signal output end of the main power control module is connected to the controlled end of the second switch control module 5. When the main power stops supplying power, the main power switch module 2 controls the first switch control module 4 to turn off and the second switch control module 5 to turn on through the power feedback signal collected by the power failure detection module 3, so as to provide a low on-resistance of the battery discharge path, thereby discharging the battery or capacitor.

[0030] In this embodiment, the transformer power supply module 1 can adopt a variety of transformer designs, such as using an isolated power transformer to convert the high voltage of the mains into a suitable low-voltage DC output, so as to provide a stable power supply for other modules in the circuit. By using a voltage stabilizing module, the stability of the power supply voltage is further guaranteed to prevent system instability caused by mains fluctuations. In addition, the transformer power supply module 1 can integrate overvoltage, overcurrent and short-circuit protection functions to ensure that when the voltage is too high or the circuit is abnormal, the power supply can be cut off in time to avoid damage to subsequent circuits and modules. At the same time, the module can output multiple voltages to supply power to the main power supply part and independently provide sufficient voltage for charging the backup battery; the main power switch module 2 is designed as a core control unit, which is responsible for receiving signal feedback from the power-off detection module 3 and controlling the switch module of the system according to actual conditions. When the mains power supply is normal, the main power switch module 2 will keep the first switch control module 4 turned on to ensure that the mains power directly supplies power to the system; when the mains power fails, the main power switch module 2 will promptly close the first switch control module 4 to cut off the mains power supply path, and at the same time open the second switch control module 5 to switch to the power supply path of the battery management module 6. The advantage of this design is that the power supply can be switched quickly and automatically, avoiding power supply interruption caused by power failure and ensuring stable operation of the system.

[0031] Preferably, the DC-DC module 7 is used to convert the DC voltage output by the transformer power supply module 1 into a stable voltage required by the system. By using efficient DC-DC conversion technology, the module can always provide a constant output voltage when the input voltage range fluctuates, ensuring stable power supply of the system load. At the same time, the DC-DC module 7 usually has overvoltage, overcurrent and short circuit protection functions, which can protect circuit components from damage under abnormal conditions. In addition, the module can also monitor the output voltage in real time through a feedback loop, and automatically adjust it to ensure stable power supply; the core function of the power-off detection module 3 is to monitor the change of the mains voltage, and send a signal when the mains power is off, triggering the main power switch module 2 to perform power supply switching. The module integrates a voltage acquisition network 31, detects the real-time voltage of the mains through a resistor voltage divider network, and transmits the collected voltage signal to the voltage stabilizing unit 32. The voltage stabilizing unit 32 converts the voltage signal into a digital signal through an optical coupler, and finally transmits it to the main power switch module 2. This design can not only detect the power-off state of the mains in real time and accurately, but also avoid misjudgment caused by instantaneous voltage fluctuations, and improve the reliability of power-off detection.

[0032] In summary, by adopting the above-mentioned line voltage power-off detection circuit, the problem of lack of safe discharge of internal input capacitors in traditional charging circuits, which constitutes the risk of electric shock, can be effectively solved. When the mains power is cut off, the power-off detection module 3 can promptly collect the signal of the removal of the mains power, and transmit this signal to the main power switch module 2. The main power switch module 2 controls the first switch control module 4 to turn off according to the detection signal, cuts off the power supply path related to the mains power in the circuit, and controls the second switch control module 5 to turn on, so that the battery or capacitor in the battery management module 6 is discharged through a low on-resistance. Through this design, the input capacitor can be quickly discharged to a safe low voltage after the mains power is disconnected, avoiding the capacitor from maintaining a high voltage state for a long time, thereby reducing the risk of electric shock and ensuring the safety of users and equipment. This automated discharge mechanism not only improves safety, but also ensures that the charge of the capacitor can be quickly released without causing potential danger to subsequent operators.

[0033] Specifically, Figure 1-2 As shown, the power-off detection module 3 includes a voltage acquisition network 31, a resistor R4, a voltage stabilizing unit 32 and an optical coupler, the optical coupler includes a light-emitting diode OC1a and a transistor OC1b, the power output end of the transformer power supply module 1 is connected to the first conductive end of the voltage acquisition network 31, the second conductive end of the voltage acquisition network 31 is grounded, the power output end of the transformer power supply module 1 is connected to the first end of the resistor R4, the second end of the resistor R4 is connected to the positive end of the light-emitting diode OC1a, and the negative end of the light-emitting diode OC1a is connected to the positive end of the light-emitting diode OC1a. The first conduction end of the voltage stabilizing unit 32 is connected, the second conduction end of the voltage stabilizing unit 32 is grounded, the signal output end of the voltage acquisition network 31 is connected to the signal input end of the voltage stabilizing unit 32, the signal input end of the main power switch module 2 is connected to the first conduction end of the transistor OC1b, the second conduction end of the transistor OC1b is grounded, the voltage stabilizing unit 32 controls the current conduction amount of the transistor OC1b by adjusting the current conduction amount of the light-emitting diode OC1a, so that the main power switch module 2 obtains the corresponding signal change.

[0034] In this embodiment, the power failure detection module 3 includes a voltage acquisition network 31, a resistor R4, a voltage stabilizing unit 32 and an optical coupler, wherein the optical coupler is composed of a light emitting diode OC1a and a transistor OC1b. The power output end of the transformer power supply module 1 is connected to the first conduction end of the voltage acquisition network 31, and the second conduction end of the voltage acquisition network 31 is grounded to ensure stability and safety during the voltage acquisition process. The power output end of the transformer power supply module 1 is also connected to the first end of the resistor R4, and the function of the resistor R4 is to limit the amount of current passing through the light emitting diode OC1a, thereby protecting the diode from damage. The positive terminal of the light emitting diode OC1a is connected to the second end of the resistor R4, and the negative terminal is connected to the first conduction end of the voltage stabilizing unit 32. The voltage stabilizing unit 32 adjusts the working current of the diode to ensure its normal operation, and its second conduction end is grounded. The signal output end of the voltage acquisition network 31 is connected to the signal input end of the voltage stabilizing unit 32, and the main power switch module 2 receives the voltage signal by connecting to the first conduction end of the transistor OC1b, thereby controlling the state of the switch according to the conduction condition of the transistor. The second conduction terminal of transistor OC1b is grounded, and the current conduction amount of light-emitting diode OC1a is adjusted by voltage stabilizing unit 32, thereby indirectly adjusting the conduction current of transistor OC1b, so that main power switch module 2 obtains corresponding signal changes to realize power failure detection and response.

[0035] In summary, the optocoupler of the power-off detection module 3 controls the current conduction of the light-emitting diode OC1a and the transistor OC1b, so that the main power switch module 2 can obtain accurate power-off signal feedback, thereby accurately controlling the on or off state of the first switch control module 4 and the second switch control module 5. This design improves the accuracy and response speed of power-off detection, ensuring that the system can switch to the backup power supply in time when the mains power is off.

[0036] Specifically, Figure 2 As shown, the voltage acquisition network 31 includes a resistor R2 and a resistor R3, the power output end of the transformer power supply module 1 is connected to the first end of the resistor R2, the second end of the resistor R2 is connected to the first end of the resistor R3, the second end of the resistor R3 is grounded, and the common node between the resistor R2 and the resistor R3 is connected to the signal input end of the voltage stabilizing unit 32.

[0037] In this embodiment, the voltage acquisition network 31 includes a resistor R2 and a resistor R3. The power output end of the transformer power supply module 1 is connected to the first end of the resistor R2, and the resistor R2 is used to distribute the voltage entering the voltage acquisition network 31. The second end of the resistor R2 is connected to the first end of the resistor R3 to form a voltage divider circuit, and the second end of the resistor R3 is grounded. The cooperation of the resistors R2 and R3 ensures that the voltage can be stably output and provide a suitable signal to the voltage stabilizing unit 32. The voltage acquisition network 31 converts the voltage signal provided by the transformer power supply module 1 into a signal that can be processed by the voltage stabilizing unit 32, which is further used to control other components in the system.

[0038] In summary, through the voltage-dividing design of resistors R2 and R3 in the voltage acquisition network 31, the change of the mains voltage can be effectively detected, and the input signal can be adjusted by the voltage stabilizing unit 32 so that the main power switch module 2 can receive the voltage change information in time, thereby realizing accurate monitoring of the mains power failure and improving the voltage detection sensitivity and response efficiency of the entire system.

[0039] Specifically, Figure 2 As shown, the power-off detection module 3 also includes a capacitor C2, a common node between the resistor R2 and the resistor R3 is connected to a first end of the capacitor C2, and a common node between the negative end of the light-emitting diode OC1a and the voltage stabilizing unit 32 is connected to a second end of the capacitor C2.

[0040] In this embodiment, the power-off detection module 3 also includes a capacitor C2. The common node between the resistor R2 and the resistor R3 is connected to the first end of the capacitor C2. The capacitor is added to stabilize the voltage output to prevent system malfunction caused by instantaneous voltage fluctuations. The common node between the negative terminal of the light-emitting diode OC1a and the voltage stabilizing unit 32 is connected to the second end of the capacitor C2. The presence of the capacitor C2 enhances the anti-interference ability of the power-off detection module 3 and further ensures the accuracy of the power-off detection signal. This design helps to improve the working reliability and durability of the module and ensure that it can respond quickly and accurately in the event of a power failure.

[0041] In summary, by adding capacitor C2 to the voltage acquisition network 31, the instantaneous interference signal in the mains voltage can be further filtered out to ensure a more stable voltage detection process. The addition of capacitor C2 not only improves the detection accuracy, but also effectively prevents malfunctions caused by voltage fluctuations, thereby improving the overall reliability of the system.

[0042] Specifically, Figure 2 As shown, the voltage stabilizing unit 32 includes at least one voltage stabilizer, and the model of the voltage stabilizer is TL431.

[0043] In this embodiment, TL431, as an adjustable precision voltage regulator, is used to control the current conduction of the light-emitting diode OC1a and the conduction state of the transistor OC1b. The introduction of TL431 ensures that the system can work stably under different input voltage conditions. By adjusting the working point of the voltage regulator, the working current of the light-emitting diode and the optocoupler can be effectively adjusted, ensuring that the power-off detection module 3 can still accurately detect the power-off signal when the voltage fluctuates.

[0044] In summary, the voltage stabilizing unit 32 can accurately stabilize the input voltage signal by using the TL431 voltage regulator, ensuring that the main power switch module 2 receives a stable voltage feedback signal. The TL431 voltage regulator has a high-precision voltage stabilizing characteristic, making the voltage detection of the entire power failure detection module 3 more stable and reliable, thereby improving the response accuracy of the system when the mains power fails.

[0045] Specifically, Figure 2 As shown, the main power switch module 2 includes a control chip U1, and the first switch control module 4 includes a MOS tube M1 and a resistor R CS The first conducting end of the MOS tube M1 is connected to the power output end of the transformer power supply module 1, and the second conducting end of the MOS tube M1 is connected to the resistor R CS The first end of the resistor R CS The second end of is grounded, the signal input end of the control chip U1 is connected to the signal output end of the power-off detection module 3, and the signal output end of the control chip U1 is connected to the controlled end of the MOS tube M1.

[0046] In this embodiment, the first switch control module 4 uses the MOS tube M1 as a core component, which can quickly realize the switch on or off according to the control signal of the main power switch module 2. When the mains power is normally supplied, the MOS tube M1 is turned on, and the mains voltage can directly power the DC-DC module 7 through the MOS tube; when the mains power is off, the main power switch module 2 sends a shutdown signal, and the MOS tube M1 is quickly turned off to cut off the power supply path of the mains power, so as to avoid unnecessary interference to the circuit after the mains power is off. At the same time, through the low on-resistance design of the MOS tube, the power loss in the on state can be reduced, and the power supply efficiency can be improved. The control of the MOSFET switch is controlled by the PWM / PFM (pulse width modulation or frequency modulation) signal, so as to determine whether to turn on according to the state of the input power supply, thereby providing a stable voltage output to the DC / DC converter.

[0047] In summary, the main power switch module 2 can quickly turn off or turn on the first switch control module 4 when the power failure detection module 3 sends a signal through the coordinated work of the control chip U1 and the MOS tube M1. The MOS tube M1 ensures the rapidity and stability of power switching when the mains power fails by accurately controlling the conduction state, thereby avoiding the problem of unstable power supply of the system caused by switching delay.

[0048] Specifically, Figure 1 As shown, the battery management module 6 includes a battery and a battery charging control unit, the power input end of the battery charging control unit is connected to the power output end of the transformer power supply module 1, the power output end of the battery charging control unit is connected to the power input end of the battery, the power output end of the battery is connected to the power input end of the second switch control module 5, and the signal input end of the battery charging control unit is connected to the signal output end of the main power control module.

[0049] In this embodiment, the second switch control module 5 also adopts a MOS tube structure, but its function is opposite to that of the first switch control module 4, and is mainly responsible for conducting the battery power supply path when the mains power is lost. Specifically, when the main power switch module 2 detects that the mains power is lost, it will send a signal to turn on the second switch control module 5, so that the battery in the battery management module 6 can power the DC-DC module 7 through the switch, ensuring the continuous and stable power supply of the system after the mains power is lost. This design realizes the automatic switching function of the backup power supply, ensuring that in the case of a mains power failure, the system can seamlessly switch from mains power supply to battery power supply; the battery management module 6 not only includes a battery, but also includes a battery charging control unit for charging and discharging management of the battery. This unit can intelligently adjust the charging and discharging state of the battery according to the mains power supply situation. When the mains power is normally supplied, the battery management module 6 will give priority to using the mains power to charge the battery to ensure that the battery has sufficient power in the standby state; and when the mains power is lost, the module will automatically stop charging and switch to the discharge mode, and provide a stable voltage for the system through the battery. Such a design ensures that the battery management module 6 can respond immediately when the mains power is lost to avoid power interruption.

[0050] In summary, the battery management module 6 can effectively charge the battery when the mains is normally powered by electricity through the cooperation of the battery and the battery charging control unit, and quickly switch to battery power supply when the mains fails. This not only ensures that the battery has sufficient power in the standby state, but also can respond quickly when the mains fails, thus achieving a stable and uninterrupted power supply function.

[0051] Specifically, Figure 2As shown, the transformer power supply module 1 includes a transformer T1 and a clamping circuit, the transformer T1 includes a primary winding Lp and a secondary winding Ls, the first end of the primary winding Lp is connected to the AC power, the common node between the second end of the primary winding Lp and the first end of the clamping circuit is connected to the power input end of the first switch control module 4, the second end of the clamping circuit is connected to the first end of the primary winding Lp, and the power output end of the secondary winding Ls is connected to the signal acquisition end of the power-off detection module 3.

[0052] In this embodiment, the transformer power supply module 1 can step down the mains voltage and stabilize it to the required operating voltage through the internal transformer and clamping circuit design. At the same time, the addition of the clamping circuit can effectively clamp the high voltage pulses in the mains input to prevent transient overvoltage or spikes from impacting subsequent circuits. In addition, the module is also equipped with an electromagnetic interference (EMI) filter, which can effectively suppress high-frequency noise and electromagnetic interference in the mains to ensure the normal operation of the circuit. Such a design ensures the stability of the power supply and the reliability of the voltage.

[0053] To sum up, the transformer power supply module 1 can effectively convert the mains voltage into the required power supply voltage through the design of transformer T1 and clamping circuit, and prevent the mains voltage fluctuation or abnormality from damaging other modules of the system through the protection of the clamping circuit, thereby ensuring the stability and safety of power supply.

[0054] Specifically, Figure 2 As shown, the clamping circuit includes a diode D1, a resistor R1 and a capacitor C1, the positive terminal of the diode D1 is connected to the second end of the primary winding Lp, the negative terminal of the diode D1 is connected to the first end of the resistor R1, the second end of the resistor R1 is connected to the first end of the primary winding Lp, the negative terminal of the diode D1 is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is connected to the first end of the primary winding Lp.

[0055] In the present embodiment, the clamping circuit includes a diode D1, a resistor R1 and a capacitor C1. The positive terminal of the diode D1 is connected to the second end of the primary winding Lp, and the function of the diode is to prevent the voltage from being reversely impacted and to protect the circuit from being damaged. The negative terminal of the diode D1 is connected to the first end of the resistor R1, and the resistor R1 plays a current limiting role to prevent the excessive current in the circuit from causing heating or other problems. The second end of the resistor R1 is connected to the first end of the primary winding Lp to ensure that the entire circuit forms a complete loop. The negative terminal of the diode D1 is also connected to the first end of the capacitor C1, and the capacitor C1 is used to store charge and reduce voltage fluctuations. The second end of the capacitor C1 is connected to the first end of the primary winding Lp, and the entire clamping circuit ensures that the system can respond quickly and protect the safety of the core components in the event of an overvoltage.

[0056] In summary, the synergistic effect of the diode D1, resistor R1 and capacitor C1 in the clamping circuit can effectively clamp the voltage during the mains power supply process to prevent the instantaneous overshoot or fluctuation of the mains voltage from affecting the normal operation of the system. At the same time, the addition of capacitor C1 can further stabilize the voltage and ensure the stability and reliability of the system power supply.

[0057] Specifically, a detection method of a line voltage power-off detection circuit is applied to a line voltage power-off detection circuit, and the detection method includes: S10, obtaining the minimum power supply voltage value required for charging and the input power supply voltage value; S20, comparing the minimum power supply voltage value required for charging with the input power supply voltage value; S30, if the input power supply voltage value is greater than the minimum power supply voltage value required for charging, control the first switch control module 4 to be turned on, so that the mains power supplies power to the DC-DC module 7 and charges the battery in the battery management module 6; S40, if the input power supply voltage value is less than the minimum power supply voltage value required for charging, control the first switch control module 4 to be disconnected and the second switch control module 5 to be connected, so that the battery supplies power to the DC-DC module 7, and stops charging the battery in the battery management module 6.

[0058] In this embodiment, the detection method is designed to ensure automatic and smooth switching between the mains power supply state and the battery power supply state. By detecting the comparison between the input power supply voltage and the minimum power supply voltage required for charging, the system can intelligently determine when to switch to battery power supply. When the mains voltage is normal, the system will turn on the mains power supply through the first switch control module 4 and charge the battery at the same time; and when the mains voltage drops below the set minimum power supply voltage, the system will automatically close the mains power supply path and open the battery power supply path. This detection method not only ensures the power supply stability of the system, but also can respond in time when the voltage fluctuates or the mains power is lost, ensuring the continuous power supply of the system.

[0059] More specifically, when the input power Vin is greater than the minimum power supply voltage required for charging, Vin charges the battery through the battery charging control module until it is fully charged, and at the same time directly provides the high-efficiency output stable voltage Vout after DC / DC conversion through the first switch control module 4. The battery serves as a backup power supply; When the input power Vin is less than the minimum power supply voltage required for charging, the body control module and the power-off detection module 3 turn off the first switch control module 4 to prevent the battery from reversely leaking. The battery charging control module is turned off, and the second switch control module 5 is turned on to provide a low on-resistance for the battery discharge path. At this time, the battery provides a stable output Vout through the DC / DC as the input of the DC / DC. Therefore, when Vin is powered, it not only charges the battery to ensure that the battery is fully charged, but also directly provides the DCDC input power supply to provide a stable DCDC output voltage Vout. When Vin loses power, the output naturally switches to battery power. As long as there is a battery, the system can still smoothly and uninterruptedly achieve stable output when the input power is off until the battery is exhausted, thereby realizing an uninterrupted power supply function.

[0060] like Figure 3 As shown, this waveform (AC RM waveform) can be directly related to the voltage drop detection circuit in the technical solution, especially in the monitoring and control of voltage changes after the high-voltage equipment is unplugged from the adapter: HV700V (yellow, high voltage input voltage): This waveform represents the input high voltage and shows the voltage decay process when the adapter is unplugged. This is closely related to the power failure detection module 3 involved in the technical solution, especially monitoring the input voltage change through the transformer power supply module 1 and the voltage acquisition network 31. In the process of the high voltage input gradually decaying, the power failure detection module 3 can obtain the signal in time and trigger the subsequent power failure processing operation.

[0061] LINE_SLOPE (blue-green, voltage drop rate detection signal): This waveform represents the rate detection signal of voltage drop, which helps the detection system to confirm the trend of voltage change. This is related to the working mechanism of the voltage stabilizing unit 32 and the optocoupler (light emitting diode OC1a and transistor OC1b) in the power failure detection module 3. When the high voltage power supply is unplugged, the system can monitor the voltage change rate to decide when to perform appropriate discharge and protection operations.

[0062] LINE_RM (blue, AC RM detected signal): This signal is directly related to the power failure detection function, indicating whether the mains power is disconnected. Through the cooperation of the voltage acquisition network 31 and the voltage stabilization unit 32, the technical solution can respond in time when the mains power is disconnected, ensuring the safe operation of the system and triggering the main power switch module 2.

[0063] SEL_DIS (purple, internal capacitor discharge): This waveform shows the process of the system discharging the internal capacitor after detecting a voltage drop. This is similar to the function of capacitor C2 in the technical solution, which is used to perform a stable discharge operation after power failure to prevent safety problems caused by residual voltage. This solves the risk of electric shock in traditional charging circuits due to residual high voltage in the internal input capacitor.

[0064] The waveforms shown in this waveform diagram are directly related to the voltage drop detection function and capacitor discharge mechanism in this technical solution. By monitoring the attenuation process of the high-voltage input voltage and promptly starting the discharge operation of the internal capacitor, the voltage safety problem after the adapter is unplugged can be effectively solved, especially avoiding the risk of electric shock caused by the residual voltage of the internal capacitor. This is also closely related to the safety of the improved charging circuit mentioned in the technical solution.

[0065] In summary, when the input power supply voltage value is greater than the minimum power supply voltage value required for charging, the system is turned on through the first switch control module 4 to ensure that the mains power supplies and charges the DC-DC module 7 and the battery at the same time; when the input power supply voltage value is lower than the required voltage value, the system automatically switches to battery power supply to ensure that the system can continuously provide stable voltage to the load when the mains power is off. This power management method improves the reliability of the system and avoids equipment operation interruption caused by unstable power supply.

[0066] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0067] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A line voltage power-off detection circuit, characterized in that: The line voltage power failure detection circuit comprises a transformer power supply module (1), a main power switch module (2), a power failure detection module (3), a first switch control module (4), a second switch control module (5), a battery management module (6) and a DC-DC module (7), wherein the power input end of the transformer power supply module (1) is connected to the mains, the power output end of the transformer power supply module (1) is connected to the power input end of the first switch control module (4), the power output end of the first switch control module (4) is connected to the power input end of the DC-DC module (7), the power output end of the transformer power supply module (1) is connected to the power input end of the battery management module (6) for supplying power to the battery in the battery management module (6), the power output end of the battery management module (6) is connected to the first conduction end of the second switch control module (5), and the second conduction end of the second switch control module (5) is connected to the power input end of the DC-DC module (7). The power supply output end of the transformer power supply module (1) is connected to the power input end of the DC-DC module (7); the power output end of the DC-DC module (7) is used to output a stable voltage to the load for power supply; the power output end of the transformer power supply module (1) is connected to the signal acquisition end of the power failure detection module (3); the signal output end of the power failure detection module (3) is connected to the signal input end of the main power control module; the first signal output end of the main power control module is connected to the controlled end of the first switch control module (4); the second signal output end of the main power control module is connected to the controlled end of the second switch control module (5); when the main power stops supplying electricity, the main power switch module (2) controls the first switch control module (4) to turn off and the second switch control module (5) to turn on through the power feedback signal collected by the power failure detection module (3), so as to provide a low on-resistance of the battery discharge path, thereby discharging the battery or capacitor.

2. A line voltage drop detection circuit according to claim 1, characterized in that: The power failure detection module (3) comprises a voltage acquisition network (31), a resistor R4, a voltage stabilizing unit (32) and an optical coupler, wherein the optical coupler comprises a light emitting diode OC1a and a transistor OC1b, the power output end of the voltage conversion power supply module (1) is connected to the first conduction end of the voltage acquisition network (31), the second conduction end of the voltage acquisition network (31) is grounded, the power output end of the voltage conversion power supply module (1) is connected to the first end of the resistor R4, the second end of the resistor R4 is connected to the positive end of the light emitting diode OC1a, the negative end of the light emitting diode OC1a is connected to the positive end of the stabilizing unit (32), and the negative end of the light emitting diode OC1a is connected to the positive end of the stabilizing unit (32). The first conductive end of the voltage stabilizing unit (32) is connected to the first conductive end of the voltage collecting network (31), the second conductive end of the voltage stabilizing unit (32) is grounded, the signal output end of the voltage collecting network (31) is connected to the signal input end of the voltage stabilizing unit (32), the signal input end of the main power switch module (2) is connected to the first conductive end of the triode OC1b, the second conductive end of the triode OC1b is grounded, and the voltage stabilizing unit (32) controls the current conduction of the triode OC1b by adjusting the current conduction of the light emitting diode OC1a, thereby enabling the main power switch module (2) to obtain the corresponding signal change.

3. A line voltage drop detection circuit according to claim 2, characterized in that: The voltage acquisition network (31) comprises a resistor R2 and a resistor R3, the power supply output end of the voltage-converting power supply module (1) is connected to the first end of the resistor R2, the second end of the resistor R2 is connected to the first end of the resistor R3, the second end of the resistor R3 is grounded, and the common node between the resistor R2 and the resistor R3 is connected to the signal input end of the voltage stabilizing unit (32).

4. A line voltage drop detection circuit according to claim 3, characterized in that: The power-off detection module (3) further comprises a capacitor C2, a common node between the resistor R2 and the resistor R3 is connected to a first end of the capacitor C2, and a common node between a negative terminal of the light-emitting diode OC1a and the voltage stabilizing unit (32) is connected to a second end of the capacitor C2.

5. A line voltage drop detection circuit according to claim 2, characterized in that: The voltage stabilizing unit (32) comprises at least one voltage stabilizer, the model of the voltage stabilizer is TL431.

6. A line voltage drop detection circuit according to claim 1, characterized in that: The main power switch module (2) comprises a control chip U1, and the first switch control module (4) comprises a MOS tube M1 and a resistor R CS The first conducting end of the MOS tube M1 is connected to the power output end of the transformer power supply module (1), and the second conducting end of the MOS tube M1 is connected to the resistor R CS The first end of the resistor R CS The second end of is grounded, the signal input end of the control chip U1 is connected to the signal output end of the power-off detection module (3), and the signal output end of the control chip U1 is connected to the controlled end of the MOS tube M1.

7. A line voltage drop detection circuit according to claim 1, characterized in that: The battery management module (6) comprises a battery and a battery charging control unit, wherein the power input end of the battery charging control unit is connected to the power output end of the transformer power supply module (1), the power output end of the battery charging control unit is connected to the power input end of the battery, the power output end of the battery is connected to the power input end of the second switch control module (5), and the signal input end of the battery charging control unit is connected to the signal output end of the main power control module.

8. A line voltage drop detection circuit according to claim 1, characterized in that: The transformer power supply module (1) comprises a transformer T1 and a clamping circuit, wherein the transformer T1 comprises a primary winding Lp and a secondary winding Ls, wherein a first end of the primary winding Lp is connected to the mains, a common node between a second end of the primary winding Lp and a first end of the clamping circuit is connected to a power input end of the first switch control module (4), a second end of the clamping circuit is connected to a first end of the primary winding Lp, and a power output end of the secondary winding Ls is connected to a signal acquisition end of the power failure detection module (3).

9. A line voltage drop detection circuit according to claim 8, characterized in that: The clamping circuit includes a diode D1, a resistor R1 and a capacitor C1, the positive terminal of the diode D1 is connected to the second end of the primary winding Lp, the negative terminal of the diode D1 is connected to the first end of the resistor R1, the second end of the resistor R1 is connected to the first end of the primary winding Lp, the negative terminal of the diode D1 is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is connected to the first end of the primary winding Lp.

10. A detection method of a line voltage power-off detection circuit, applied to a line voltage power-off detection circuit as claimed in any one of claims 1 to 9, characterized in that: The detection method comprises: Obtain the minimum power supply voltage value required for charging and the input power supply voltage value; Comparing the minimum power supply voltage value required for charging with the input power supply voltage value; If the input power supply voltage value is greater than the minimum power supply voltage value required for charging, the first switch control module is controlled to be turned on so that the mains power supplies power to the DC-DC module and charges the battery in the battery management module; If the input power supply voltage value is less than the minimum power supply voltage value required for charging, the first switch control module is controlled to be disconnected and the second switch control module is controlled to be connected, so that the battery supplies power to the DC-DC module and stops charging the battery in the battery management module.

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