Line voltage brown-out detection circuit and method of detecting same

Abstract

The application relates to a line voltage power failure detection circuit and a detection method thereof. The line voltage power failure detection circuit comprises a variable voltage power supply module, a main power switch module, a power failure detection module, a first switch control module and a second switch control module. The power output end of the variable voltage power supply module is connected with the signal collection 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. The second signal output end of the main power control module is connected with the controlled end of the second switch control module. When the commercial power supply stops, the main power switch module controls the first switch control module to be closed and the second switch control module to be opened, so that the battery or the capacitor is discharged, the capacitor is prevented from being kept in a high-voltage state for a long time, and the risk of electric shock is reduced.

Description

Technical Field

[0001] This invention relates to the technical field of a line voltage power failure detection circuit, and more particularly to a line voltage power failure detection circuit and its detection method. Background Technology

[0002] Currently, AC / DC adapters do sometimes leave high voltage residue in their internal capacitors when unplugged. This phenomenon is mainly because the capacitors inside the adapter retain their charge after the device is powered off. These capacitors can store high voltage, especially when there is no load. High-power appliances will still have high voltage in their internal input capacitors after power is cut off, which poses a risk of electric shock. Therefore, it is necessary to safely discharge the internal input capacitors, but traditional charging circuits lack this function. Summary of the Invention

[0003] To address the problem that traditional charging circuits lack the ability to safely discharge internal input capacitors, thus posing a contact risk, this application provides a line voltage power failure detection circuit and its detection method.

[0004] A line voltage power failure detection circuit includes a transformer power supply module, a main power switch module, a power failure detection module, a first switch control module, a second switch control module, a battery management module, and a DC-DC module. The power input terminal of the transformer power supply module is connected to AC mains power. The power output terminal of the transformer power supply module is connected to the power input terminal of the first switch control module. The power output terminal of the first switch control module is connected to the power input terminal of the DC-DC module. The power output terminal of the transformer power supply module is connected to the power input terminal of the battery management module to power the battery in the battery management module. The power output terminal of the battery management module is connected to the first conducting terminal of the second switch control module, and the second conducting terminal of the second switch control module is connected to the DC-DC module. The C-DC module's power input terminal is connected, and the DC-DC module's power output terminal is used to output a stable voltage to the load for power supply. The power output terminal of the transformer power supply module is connected to the signal acquisition terminal of the power failure detection module, and the signal output terminal of the power failure detection module is connected to the signal input terminal of the main power switch module. The first signal output terminal of the main power switch module is connected to the controlled terminal of the first switch control module, and the second signal output terminal of the main power switch module is connected to the controlled terminal of the second switch control module. When the mains power supply stops, 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 acquired by the power failure detection module, so as to provide a low on-resistance for the battery discharge path and thus discharge the battery.

[0005] By adopting the above technical solution and the line voltage power-off detection circuit, the problem of electric shock risk caused by the lack of safe discharge of internal input capacitors in traditional charging circuits can be effectively solved. When the mains power is interrupted, the power-off detection module can promptly collect the signal of mains power removal and transmit this signal to the main power switch module. Based on the detection signal, the main power switch module controls the first switch control module to close, cutting off the power supply path related to the mains power in the circuit, and simultaneously controls the second switch control module to open, allowing the battery or capacitor in the battery management module to discharge through low on-resistance. Through this design, the input capacitor can quickly discharge 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 capacitor's charge is released quickly, without posing a potential danger to subsequent operators.

[0006] Preferably, the power failure detection module includes a voltage acquisition network, a resistor R4, a voltage regulator unit, and an optocoupler. The optocoupler includes a light-emitting diode OC1a and a transistor OC1b. The power output terminal of the transformer power supply module is connected to the first conducting terminal of the voltage acquisition network, and the second conducting terminal of the voltage acquisition network is grounded. The power output terminal of the transformer power supply module is connected to the first terminal of the resistor R4, and the second terminal of the resistor R4 is connected to the positive terminal of the light-emitting diode OC1a. The negative terminal of the light-emitting diode OC1a is connected to the first conducting terminal of the voltage regulator unit, and the second conducting terminal of the voltage regulator unit is grounded. The signal output terminal of the voltage acquisition network is connected to the signal input terminal of the voltage regulator unit. The signal input terminal of the main power switch module is connected to the first conducting terminal of the transistor OC1b, and the second conducting terminal of the transistor OC1b is grounded. The voltage regulator unit controls the current conduction of the transistor OC1b by adjusting the current conduction 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, enabling the main power switching module to obtain accurate power failure signal feedback. This allows for precise control of the on / off state of the first and second switch control modules. This design improves the accuracy and response speed of power failure detection, ensuring that the system can switch to the backup power supply in a timely manner when the mains power fails.

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

[0009] By adopting the above technical solution and using the voltage divider design of resistors R2 and R3 in the voltage acquisition network, changes in mains voltage can be effectively detected. The input signal is adjusted by the voltage regulator unit, so that the main power switch module can receive the voltage change information in a timely manner. This enables accurate monitoring of mains power failure and improves the voltage detection sensitivity and response efficiency of the entire system.

[0010] Preferably, the power failure detection module further 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, and the negative terminal of the light-emitting diode OC1a is connected to the common node between the voltage regulator unit and the second end of the capacitor C2.

[0011] By adopting the above technical solution and adding capacitor C2 to the voltage acquisition network, transient interference signals in the mains voltage can be further filtered out, ensuring a more stable voltage detection process. The addition of capacitor C2 not only improves detection accuracy but also effectively prevents malfunctions caused by voltage fluctuations, thus enhancing the overall reliability of the system.

[0012] Preferably, the voltage stabilizing unit includes at least one voltage regulator, the voltage regulator being a TL431.

[0013] By adopting the above technical solution, the voltage regulation unit, using the TL431 voltage regulator, can accurately regulate and control the input voltage signal, ensuring that the main power switching module receives a stable voltage feedback signal. The TL431 voltage regulator has high-precision voltage regulation characteristics, making the voltage detection of the entire power failure detection module more stable and reliable, thereby improving the system's response accuracy 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 MOSFET M1 and a resistor Rcs. The first conducting terminal of the MOSFET M1 is connected to the power output terminal of the transformer power supply module, the second conducting terminal of the MOSFET M1 is connected to the first terminal of the resistor Rcs, the second terminal of the resistor Rcs is grounded, the signal input terminal of the control chip U1 is connected to the signal output terminal of the power failure detection module, and the first signal output terminal of the control chip U1 is connected to the controlled terminal of the MOSFET M1.

[0015] By adopting the above technical solution, the main power switching module, through the coordinated operation of control chip U1 and MOSFET M1, can quickly turn off or on the first switching control module when the power failure detection module sends a signal. MOSFET M1, by precisely controlling its conduction state, ensures the speed and stability of power switching when the mains power fails, avoiding system power instability caused by switching delays.

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

[0017] By adopting the above technical solution, the battery management module, through the cooperation of the battery and the battery charging control unit, can effectively charge the battery when the mains power is normal and quickly switch to battery power when the mains power fails. This not only ensures that the battery has sufficient charge in standby mode, but also enables a rapid response when the mains power fails, achieving 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 mains 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 terminal of the first switch control module. The second end of the clamping circuit is connected to the first end of the primary winding Lp. The power output terminal of the secondary winding Ls is connected to the signal acquisition terminal of the power failure detection module.

[0019] By adopting the above technical solution, the transformer power supply module, through the design of transformer T1 and clamping circuit, can effectively convert the mains voltage into the required supply voltage. Through the protective function of clamping circuit, it prevents mains voltage fluctuations or abnormalities from damaging other modules in the system, thus 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 employing the above technical solution, the synergistic effect of diode D1, resistor R1, and capacitor C1 in the clamping circuit can effectively clamp the voltage during mains power supply, preventing instantaneous overshoot or fluctuations in mains voltage from affecting the normal operation of the system. Simultaneously, the addition of capacitor C1 further stabilizes the voltage, ensuring the stability and reliability of the system's power supply.

[0022] A detection method for a line voltage power failure detection circuit, applied to a line voltage power failure detection circuit, the detection method comprising:

[0023] Obtain the minimum power supply voltage required for charging, as well as the input power supply voltage.

[0024] Compare the minimum power supply voltage required for charging with the input power supply voltage.

[0025] If the input power supply voltage is greater than the minimum power supply voltage required for charging, the first switch control module is turned on so that the mains power supplies power to the DC-DC module and charges the battery in the battery management module.

[0026] If the input power supply voltage is less than the minimum power supply voltage required for charging, the first switch control module is turned off and the second switch control module is turned on, so that the battery supplies power to the DC-DC module and stops charging the battery in the battery management module.

[0027] By adopting the above technical solution, when the input power supply voltage is greater than the minimum power supply voltage required for charging, the system turns on through the first switch control module to ensure that the mains power supplies power and charges the DC-DC module and the battery simultaneously. When the input power supply voltage is lower than the required voltage, the system automatically switches to battery power, ensuring that the system can continuously provide a stable voltage to the load when the mains power fails. This power management method improves the reliability of the system and avoids equipment operation interruptions caused by power instability.

[0028] In summary, this application includes at least one of the following beneficial technical effects:

[0029] 1. By employing the aforementioned line voltage power-off detection circuit, the problem of electric shock risk arising from the lack of safe discharge of internal input capacitors in traditional charging circuits can be effectively solved. When the mains power fails, the power-off detection module can promptly acquire the signal indicating the removal of mains power and transmit this signal to the main power switch module. Based on the detection signal, the main power switch module controls the first switch control module to close, cutting off the power supply path related to mains power in the circuit, and simultaneously controls the second switch control module to open, allowing the battery or capacitor in the battery management module to discharge through low on-resistance. Through this design, the input capacitor can quickly discharge to a safe low voltage after the mains power is disconnected, avoiding the capacitor 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 capacitor's charge is released quickly, preventing potential danger to subsequent operators.

[0030] 2. When the input power supply voltage is greater than the minimum power supply voltage required for charging, the system switches on via the first switch control module to ensure that the mains power supplies the DC-DC module and the battery simultaneously. When the input power supply voltage is lower than the required voltage, the system automatically switches to battery power to ensure that the system can continuously provide a stable voltage to the load when the mains power fails. This power management method improves the reliability of the system and avoids equipment operation interruptions caused by power instability. Attached Figure Description

[0031] Figure 1 This is a flowchart of a line voltage power failure detection circuit according to one embodiment of this application.

[0032] Figure 2 This is a partial circuit diagram of a line voltage power failure detection circuit according to one embodiment of this application;

[0033] Figure 3 This is an AC RM waveform diagram associated with a line voltage power failure detection circuit in one embodiment of this application.

[0034] Explanation of reference numerals in the attached diagram: 1. Transformer power supply module; 2. Main power switch module; 3. Power failure detection module; 31. Voltage acquisition network; 32. Voltage regulation unit; 4. First switch control module; 5. Second switch control module; 6. Battery management module; 7. DC-DC module. Detailed Implementation

[0035] The present application will be further described in detail below with reference to the accompanying drawings.

[0036] Specifically, such as Figure 1As shown, a line voltage power failure detection circuit includes 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. The power input terminal of the transformer power supply module 1 is connected to the mains power. The power output terminal of the transformer power supply module 1 is connected to the power input terminal of the first switch control module 4. The power output terminal of the first switch control module 4 is connected to the power input terminal of the DC-DC module 7. The power output terminal of the transformer power supply module 1 is connected to the power input terminal of the battery management module 6 to supply power to the battery in the battery management module 6. The power output terminal of the battery management module 6 is connected to the first conducting terminal of the second switch control module 5. The second conducting terminal of the second switch control module 5 is connected to the second conducting terminal of the second switch control module 5. The power input terminal of the transformer power supply module 1 is connected to the power input terminal of the DC-DC module 7. The power output terminal of the DC-DC module 7 is used to output a stable voltage to the load for power supply. The power output terminal of the transformer power supply module 1 is connected to the signal acquisition terminal of the power failure detection module 3. The signal output terminal of the power failure detection module 3 is connected to the signal input terminal of the main power switch module. The first signal output terminal of the main power switch module is connected to the controlled terminal of the first switch control module 4. The second signal output terminal of the main power switch module is connected to the controlled terminal of the second switch control module 5. When the mains power supply stops, 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 acquired by the power failure detection module 3, so as to provide a low on-resistance for the battery discharge path and thus discharge the battery.

[0037] In this embodiment, the transformer power supply module 1 can employ various transformer designs, such as an isolated power transformer to convert the high voltage of the mains power into a suitable low-voltage DC output, thereby providing a stable power supply to other modules in the circuit. By using a voltage regulator module, the stability of the supply voltage is further ensured, preventing system instability caused by mains power fluctuations. Furthermore, the transformer power supply module 1 can integrate overvoltage, overcurrent, and short-circuit protection functions, ensuring that the power supply can be promptly cut off in case of excessive voltage or circuit abnormalities, avoiding damage to subsequent circuits and modules. Simultaneously, this module outputs multiple voltages, providing power to the main power supply section and independently charging the backup battery with sufficient voltage. The main power switch module 2 is designed as the core control unit, responsible for receiving signal feedback from the power failure detection module 3 and controlling the system's switching modules according to actual conditions. When the mains power supply is normal, the main power switch module 2 keeps the first switch control module 4 on, ensuring that the mains power directly supplies power to the system. When the mains power fails, the main power switch module 2 will promptly shut down the first switch control module 4, cutting off the mains power supply path, and simultaneously turn on the second switch control module 5, switching to the power supply path of the battery management module 6. The advantage of this design is that it can quickly and automatically switch power supplies, avoiding power interruptions caused by power failures and ensuring the stable operation of the system.

[0038] 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, this module can always provide a constant output voltage even when the input voltage fluctuates, ensuring a stable power supply to the system load. Simultaneously, the DC-DC module 7 typically has overvoltage, overcurrent, and short-circuit protection functions, protecting circuit components from damage in abnormal situations. Furthermore, this module can 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 failure detection module 3 is to monitor changes in the mains voltage and send a signal when the mains power fails, triggering the main power switching module 2 to perform power switching. This module integrates a voltage acquisition network 31, which detects the real-time mains voltage through a resistor divider network and transmits the acquired voltage signal to the voltage regulation unit 32. The voltage regulation unit 32 then converts the voltage signal into a digital signal through an optocoupler and finally transmits it to the main power switching module 2. This design not only enables accurate real-time detection of the mains power failure state but also avoids misjudgments caused by instantaneous voltage fluctuations, improving the reliability of power failure detection.

[0039] In summary, by employing the aforementioned line voltage power-off detection circuit, the problem of electric shock risk arising from the lack of safe discharge of internal input capacitors in traditional charging circuits can be effectively solved. When the mains power is interrupted, the power-off detection module 3 can promptly collect the signal indicating the removal of mains power and transmit this signal to the main power switch module 2. Based on the detection signal, the main power switch module 2 controls the first switch control module 4 to close, cutting off the power supply path related to mains power in the circuit. Simultaneously, it controls the second switch control module 5 to open, allowing the battery or capacitor in the battery management module 6 to discharge through low on-resistance. Through this design, the input capacitor can quickly discharge to a safe low voltage after the mains power is disconnected, avoiding the capacitor 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 capacitor's charge is released quickly, preventing potential danger to subsequent operators.

[0040] Specifically, such as Figure 1-2 As shown, the power failure detection module 3 includes a voltage acquisition network 31, a resistor R4, a voltage regulator unit 32, and an optocoupler. The optocoupler includes a light-emitting diode OC1a and a transistor OC1b. The power output terminal of the transformer power supply module 1 is connected to the first conducting terminal of the voltage acquisition network 31, and the second conducting terminal of the voltage acquisition network 31 is grounded. The power output terminal of the transformer power supply module 1 is connected to the first terminal of the resistor R4, and the second terminal of the resistor R4 is connected to the positive terminal of the light-emitting diode OC1a. The negative terminal of the light-emitting diode OC1a is connected to the... The first conducting terminal of the voltage regulator unit 32 is connected, the second conducting terminal of the voltage regulator unit 32 is grounded, the signal output terminal of the voltage acquisition network 31 is connected to the signal input terminal of the voltage regulator unit 32, the signal input terminal of the main power switch module 2 is connected to the first conducting terminal of the transistor OC1b, and the second conducting terminal of the transistor OC1b is grounded. The voltage regulator unit 32 controls the current conduction of the transistor 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.

[0041] In this embodiment, the power failure detection module 3 includes a voltage acquisition network 31, a resistor R4, a voltage regulator unit 32, and an optocoupler. The optocoupler consists of a light-emitting diode OC1a and a transistor OC1b. The power output terminal of the transformer power supply module 1 is connected to the first conducting terminal of the voltage acquisition network 31, and the second conducting terminal of the voltage acquisition network 31 is grounded to ensure stability and safety during voltage acquisition. The power output terminal of the transformer power supply module 1 is also connected to the first terminal of the resistor R4. The resistor R4 limits the current flowing 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 terminal of the resistor R4, and the negative terminal is connected to the first conducting terminal of the voltage regulator unit 32. The voltage regulator unit 32 adjusts the diode's operating current to ensure its normal operation, and its second conducting terminal is grounded. The signal output terminal of the voltage acquisition network 31 is connected to the signal input terminal of the voltage regulator unit 32. The main power switch module 2 receives the voltage signal by connecting to the first conducting terminal of the transistor OC1b, thereby controlling the switch state according to the transistor's conduction status. The second conducting terminal of transistor OC1b is grounded. The current conduction of light-emitting diode OC1a is adjusted by voltage regulator unit 32, which indirectly adjusts the conduction current of transistor OC1b, thereby enabling main power switch module 2 to obtain the corresponding signal change and realize power failure detection and response.

[0042] In summary, the optocoupler of the power failure detection module 3 controls the current conduction of the light-emitting diode OC1a and the transistor OC1b, enabling the main power switch module 2 to obtain accurate power failure signal feedback. This allows for precise control of the on / off states of the first switch control module 4 and the second switch control module 5. This design improves the accuracy and response speed of power failure detection, ensuring that the system can switch to the backup power supply in a timely manner when the mains power fails.

[0043] Specifically, such as Figure 2 As shown, the voltage acquisition network 31 includes resistors R2 and R3. The power output terminal of the transformer power supply module 1 is connected to the first terminal of resistor R2, the second terminal of resistor R2 is connected to the first terminal of resistor R3, the second terminal of resistor R3 is grounded, and the common node between resistors R2 and R3 is connected to the signal input terminal of the voltage regulation unit 32.

[0044] In this embodiment, the voltage acquisition network 31 includes resistors R2 and R3. The power output terminal of the transformer power supply module 1 is connected to the first terminal of resistor R2, which is used to distribute the voltage entering the voltage acquisition network 31. The second terminal of resistor R2 is connected to the first terminal of resistor R3, forming a voltage divider circuit, and the second terminal of resistor R3 is grounded. The cooperation of resistors R2 and R3 ensures that the voltage can be stably output and provides a suitable signal to the voltage regulator unit 32. Through the common node of the voltage divider circuit connected to the signal input terminal of the voltage regulator unit 32, the voltage acquisition network 31 converts the voltage signal provided by the transformer power supply module 1 into a signal that the voltage regulator unit 32 can process, and further uses it to control other components in the system.

[0045] In summary, the voltage divider design of resistors R2 and R3 in the voltage acquisition network 31 can effectively detect changes in mains voltage. By adjusting the input signal through the voltage regulator unit 32, the main power switch module 2 can receive voltage change information in a timely manner, thereby achieving accurate monitoring of mains power failure and improving the voltage detection sensitivity and response efficiency of the entire system.

[0046] Specifically, such as Figure 2 As shown, the power failure 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 negative terminal of the light-emitting diode OC1a is connected to the common node between the voltage regulator unit 32 and the second end of the capacitor C2.

[0047] In this embodiment, the power-down detection module 3 also includes a capacitor C2. The common node between resistors R2 and R3 is connected to the first terminal of capacitor C2, adding capacitance to stabilize the voltage output and prevent system malfunctions caused by instantaneous voltage fluctuations. The common node between the negative terminal of the light-emitting diode OC1a and the voltage regulator unit 32 is connected to the second terminal of capacitor C2. The presence of capacitor C2 enhances the anti-interference capability of the power-down detection module 3, further ensuring the accuracy of the power-down detection signal. This design helps improve the module's operational reliability and durability, ensuring a rapid and accurate response in the event of a power failure.

[0048] In summary, by adding capacitor C2 to the voltage acquisition network 31, transient interference signals in the mains voltage can be further filtered out, ensuring a more stable voltage detection process. The addition of capacitor C2 not only improves detection accuracy but also effectively prevents malfunctions caused by voltage fluctuations, thus enhancing the overall reliability of the system.

[0049] Specifically, such as Figure 2 As shown, the voltage regulator unit 32 includes at least one voltage regulator, which is a TL431.

[0050] In this embodiment, the 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 the TL431 ensures that the system can operate stably under different input voltage conditions. By adjusting the operating point of the voltage regulator, the operating current of the light-emitting diode and the optocoupler can be effectively adjusted, ensuring that the power-down detection module 3 can still accurately detect the power-down signal when the voltage fluctuates.

[0051] In summary, by using the TL431 voltage regulator, the voltage regulation unit 32 can accurately regulate and control the input voltage signal, ensuring that the main power switching module 2 receives a stable voltage feedback signal. The TL431 voltage regulator has high-precision voltage regulation characteristics, making the voltage detection of the entire power failure detection module 3 more stable and reliable, thereby improving the system's response accuracy when the mains power fails.

[0052] Specifically, such as Figure 2 As shown, the main power switch module 2 includes a control chip U1, and the first switch control module 4 includes a MOSFET M1 and a resistor Rcs. The first conducting terminal of the MOSFET M1 is connected to the power output terminal of the transformer power supply module 1, the second conducting terminal of the MOSFET M1 is connected to the first terminal of the resistor Rcs, the second terminal of the resistor Rcs is grounded, the signal input terminal of the control chip U1 is connected to the signal output terminal of the power failure detection module 3, and the first signal output terminal of the control chip U1 is connected to the controlled terminal of the MOSFET M1.

[0053] In this embodiment, the first switch control module 4 uses a MOSFET M1 as its core component, which can quickly turn the switch on or off according to the control signal from the main power switch module 2. When the mains power is normal, the MOSFET M1 is turned on, and the mains voltage can directly power the DC-DC module 7 through the MOSFET. When the mains power fails, the main power switch module 2 sends a shutdown signal, and the MOSFET M1 quickly turns off, cutting off the mains power supply path and avoiding unnecessary interference to the circuit after the mains power fails. At the same time, the low on-resistance design of the MOSFET can reduce power loss in the on state and improve power supply efficiency. The MOSFET switch is controlled by PWM / PFM (pulse width modulation or frequency modulation) signals, which determines whether to turn on according to the state of the input power supply, thereby providing a stable voltage output to the DC / DC converter.

[0054] In summary, the main power switch module 2, through the coordinated operation of the control chip U1 and the MOSFET M1, can quickly turn off or on the first switch control module 4 when the power failure detection module 3 sends a signal. The MOSFET M1, by precisely controlling its conduction state, ensures the speed and stability of power switching when the mains power fails, avoiding system power instability caused by switching delays.

[0055] Specifically, such as Figure 1 As shown, the battery management module 6 includes a battery and a battery charging control unit. The power input terminal of the battery charging control unit is connected to the power output terminal of the transformer power supply module 1. The power output terminal of the battery charging control unit is connected to the power input terminal of the battery. The power output terminal of the battery is connected to the first conducting terminal of the second switch control module 5. The signal input terminal of the battery charging control unit is connected to the third signal output terminal of the main power switch module 2.

[0056] In this embodiment, the second switch control module 5 also adopts a MOSFET structure, but its function is opposite to that of the first switch control module 4, mainly responsible for connecting the battery power supply path when the mains power fails. Specifically, when the main power switch module 2 detects a mains power failure, it sends a signal to activate the second switch control module 5, enabling the battery in the battery management module 6 to supply power to the DC-DC module 7 through the switch, ensuring a continuous and stable power supply to the system after a mains power failure. This design realizes the automatic switching function of the backup power supply, ensuring that the system can seamlessly switch from mains power supply to battery power supply in the event of a mains power failure. The battery management module 6 includes not only the battery but also a battery charging control unit for managing the charging and discharging of the battery. This unit can intelligently adjust the charging and discharging state of the battery according to the mains power supply status. When the mains power is normal, the battery management module 6 will prioritize using the mains power to charge the battery, ensuring that the battery has sufficient charge in the standby state; when the mains power fails, the module will automatically stop charging and switch to the discharging mode, providing a stable voltage to the system through the battery. This design ensures that the battery management module 6 can respond immediately in the event of a mains power failure, avoiding power interruption.

[0057] In summary, the battery management module 6, through the cooperation of the battery and the battery charging control unit, can effectively charge the battery when the mains power is normal and quickly switch to battery power when the mains power fails. This not only ensures that the battery has sufficient charge in standby mode, but also enables a rapid response when the mains power fails, achieving a stable and uninterrupted power supply function.

[0058] Specifically, such as Figure 2 As 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 mains 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 terminal 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. The power output terminal of the secondary winding Ls is connected to the signal acquisition terminal of the power failure detection module 3.

[0059] In this embodiment, the transformer power supply module 1, through its internal transformer and clamping circuit design, can step down and stabilize the mains voltage to the required operating voltage. Simultaneously, the clamping circuit effectively clamps high-voltage pulses in the mains input, preventing transient overvoltages or spikes from impacting subsequent circuits. Furthermore, the module is equipped with an electromagnetic interference (EMI) filter, which effectively suppresses high-frequency noise and electromagnetic interference in the mains power supply, ensuring normal circuit operation. This design guarantees the stability of the power supply and the reliability of the voltage.

[0060] In summary, the transformer power supply module 1, through the design of transformer T1 and clamping circuit, can effectively convert the mains voltage into the required supply voltage. Through the protective function of clamping circuit, it prevents mains voltage fluctuations or abnormalities from damaging other modules in the system, thus ensuring the stability and safety of the power supply.

[0061] Specifically, such as 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.

[0062] In this embodiment, the clamping circuit includes a diode D1, a resistor R1, and a capacitor C1. The positive terminal of diode D1 is connected to the second terminal of the primary winding Lp. The diode's function is to prevent reverse voltage surges and protect the circuit from damage. The negative terminal of diode D1 is connected to the first terminal of resistor R1. Resistor R1 limits the current, preventing excessive current in the circuit from causing overheating or other problems. The second terminal of resistor R1 is connected to the first terminal of the primary winding Lp, ensuring that the entire circuit forms a complete loop. The negative terminal of diode D1 is also connected to the first terminal of capacitor C1. Capacitor C1 stores charge and reduces voltage fluctuations. The second terminal of capacitor C1 is connected to the first terminal of the primary winding Lp. The entire clamping circuit ensures that the system can respond quickly and protect the safety of core components in the event of overvoltage.

[0063] In summary, the synergistic effect of diode D1, resistor R1, and capacitor C1 in the clamping circuit effectively clamps the voltage during mains power supply, preventing instantaneous overshoot or fluctuations in mains voltage from affecting the normal operation of the system. Simultaneously, the addition of capacitor C1 further stabilizes the voltage, ensuring the stability and reliability of the system's power supply.

[0064] Specifically, a detection method for a line voltage power failure detection circuit is provided, applied to a line voltage power failure detection circuit, the detection method comprising:

[0065] S10. Obtain the minimum power supply voltage required for charging, and the input power supply voltage.

[0066] S20. Compare the minimum power supply voltage required for charging with the input power supply voltage.

[0067] S30. If the input power supply voltage is greater than the minimum power supply voltage required for charging, control the first switch control module 4 to turn on so that the mains power supplies power to the DC-DC module 7 and charges the battery in the battery management module 6.

[0068] S40. If the input power supply voltage is less than the minimum power supply voltage required for charging, control the first switch control module 4 to disconnect and the second switch control module 5 to connect, so that the battery supplies power to the DC-DC module 7 and stops charging the battery in the battery management module 6.

[0069] In this embodiment, the detection method is designed to ensure automatic and smooth switching between mains power and battery power. By comparing the input power supply voltage with the minimum supply voltage required for charging, the system can intelligently determine when to switch to battery power. When the mains voltage is normal, the system will connect the mains power supply through the first switch control module 4 and charge the battery simultaneously; when the mains voltage drops below the set minimum supply voltage, the system will automatically shut down the mains power supply path and open the battery power supply path. This detection method not only ensures the stability of the system's power supply but also reacts promptly to voltage fluctuations or mains power failures, ensuring continuous power supply.

[0070] More specifically, when the input power Vin is greater than the minimum 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, it directly supplies 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 source.

[0071] When the input power supply Vin is lower than the minimum supply voltage required for charging, the body control module and the power failure detection module 3 shut down the first switch control module 4 to prevent reverse leakage of the battery and shut down the battery charging control module. Simultaneously, 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 acts as the input to the DC / DC converter, providing a stable output Vout. Therefore, when Vin supplies power, it both charges the battery to ensure it is fully charged and directly provides the DC / DC input power to supply a stable output voltage Vout. When Vin loses power, the output naturally switches to battery power. As long as there is a battery, the system can smoothly and uninterruptedly achieve a stable output even when the input power is lost, until the battery is depleted, thus achieving uninterrupted power supply.

[0072] like Figure 3 As shown, this waveform diagram (AC RM waveform diagram) 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 adapter of high-voltage equipment is disconnected:

[0073] HV700V (yellow, high voltage input):

[0074] 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-down detection module 3 involved in the technical solution, especially the monitoring of input voltage changes through the transformer power supply module 1 and the voltage acquisition network 31. As the high voltage input gradually decays, the power-down detection module 3 can promptly acquire the signal and trigger subsequent power-down processing operations.

[0075] LINE_SLOPE (blue-green, the signal indicating the rate of voltage drop):

[0076] This waveform represents the rate of voltage drop detection signal, helping the detection system to confirm the trend of voltage change. This is related to the working mechanism of the voltage regulator unit 32 and the optocouplers (LED OC1a and transistor OC1b) in the power-down detection module 3. When the high-voltage power supply is disconnected, the system can determine when to perform appropriate discharge and protection operations by monitoring the rate of voltage change.

[0077] LINE_RM (blue, signal detected by AC RM):

[0078] This signal is directly related to the power failure detection function, indicating whether the mains power has been disconnected. Through the cooperation of the voltage acquisition network 31 and the voltage regulation unit 32, the technical solution can respond in a timely manner when the mains power is detected to be disconnected, ensuring the safe operation of the system and triggering the main power switching module 2.

[0079] SEL_DIS (purple, internal capacitor discharge):

[0080] This waveform represents the process of the system discharging its internal capacitor after a voltage drop is detected. This is similar to the function of capacitor C2 in the technical solution, which is used for stable discharge after a power failure to prevent safety issues caused by residual voltage. This solves the electric shock hazard caused by residual high voltage in the internal input capacitor in traditional charging circuits.

[0081] The waveforms shown in this 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 initiating the discharge operation of the internal capacitor, the voltage safety issue after the adapter is unplugged can be effectively resolved, especially avoiding the risk of electric shock caused by residual voltage in the internal capacitor. This is also closely related to the improved safety of the charging circuit mentioned in the technical solution.

[0082] In summary, when the input power supply voltage is greater than the minimum power supply voltage required for charging, the system controls the first switch module 4 to conduct, ensuring that the mains power simultaneously supplies power to and charges the DC-DC module 7 and the battery. When the input power supply voltage is lower than the required voltage, the system automatically switches to battery power, ensuring that the system can continuously provide a stable voltage to the load when the mains power fails. This power management method improves the reliability of the system and avoids equipment operation interruptions caused by power instability.

[0083] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to 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.

[0084] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A line voltage power-down detection circuit, characterized in that, The line voltage power failure detection circuit includes 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). The power input terminal of the transformer power supply module (1) is connected to the mains power, and the power output terminal of the transformer power supply module (1) is connected to the power input terminal of the first switch control module (4). The power output terminal of the first switch control module (4) is connected to the power input terminal of the DC-DC module (7). The power output terminal of the transformer power supply module (1) is connected to the power input terminal of the battery management module (6) to supply power to the battery in the battery management module (6). The power output terminal of the battery management module (6) is connected to the first conducting terminal of the second switch control module (5), and the second conducting terminal of the second switch control module (5) is connected to the DC-DC module (7). The power input terminal of the C-DC module (7) is connected, and the power output terminal of the DC-DC module (7) is used to output a stable voltage to the load for power supply. The power output terminal of the transformer power supply module (1) is connected to the signal acquisition terminal of the power failure detection module (3). The signal output terminal of the power failure detection module (3) is connected to the signal input terminal of the main power switch module (2). The first signal output terminal of the main power switch module (2) is connected to the controlled terminal of the first switch control module (4). The second signal output terminal of the main power switch module (2) is connected to the controlled terminal of the second switch control module (5). When the mains power supply stops, the main power switch module (2) controls the first switch control module (4) to close and the second switch control module (5) to open through the power feedback signal acquired by the power failure detection module (3) to provide a low on-resistance for the battery discharge path, thereby discharging the battery.

2. The line voltage power failure detection circuit according to claim 1, characterized in that, The power failure detection module (3) includes a voltage acquisition network (31), a resistor R4, a voltage regulator unit (32), and an optocoupler. The optocoupler includes a light-emitting diode OC1a and a transistor OC1b. The power output terminal of the transformer power supply module (1) is connected to the first conducting terminal of the voltage acquisition network (31), and the second conducting terminal of the voltage acquisition network (31) is grounded. The power output terminal of the transformer power supply module (1) is connected to the first terminal of the resistor R4, and the second terminal of the resistor R4 is connected to the positive terminal of the light-emitting diode OC1a. The negative terminal of the light-emitting diode OC1a is connected to the voltage regulator unit (32). The first conducting terminal of the voltage regulator unit (32) is connected, the second conducting terminal of the voltage regulator unit (32) is grounded, the signal output terminal of the voltage acquisition network (31) is connected to the signal input terminal of the voltage regulator unit (32), the signal input terminal of the main power switch module (2) is connected to the first conducting terminal of the transistor OC1b, the second conducting terminal of the transistor OC1b is grounded, and the voltage regulator unit (32) controls the current conduction of the transistor 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. The line voltage power failure detection circuit according to claim 2, characterized in that, The voltage acquisition network (31) includes resistors R2 and R3. The power output terminal of the transformer power supply module (1) is connected to the first end of resistor R2. The second end of resistor R2 is connected to the first end of resistor R3. The second end of resistor R3 is grounded. The common node between resistors R2 and R3 is connected to the signal input terminal of the voltage regulator unit (32).

4. The line voltage power failure detection circuit according to claim 3, characterized in that, The power failure 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 negative terminal of the light-emitting diode OC1a is connected to the common node between the voltage regulator unit (32) and the second end of the capacitor C2.

5. The line voltage power failure detection circuit according to claim 2, characterized in that, The voltage regulator unit (32) includes at least one voltage regulator, which is a TL431.

6. The line voltage power failure detection circuit according to claim 1, characterized in that, The main power switch module (2) includes a control chip U1. The first switch control module (4) includes a MOS transistor M1 and a resistor Rcs. The first conducting terminal of the MOS transistor M1 is connected to the power output terminal of the transformer power supply module (1). The second conducting terminal of the MOS transistor M1 is connected to the first terminal of the resistor Rcs. The second terminal of the resistor Rcs is grounded. The signal input terminal of the control chip U1 is connected to the signal output terminal of the power failure detection module (3). The first signal output terminal of the control chip U1 is connected to the controlled terminal of the MOS transistor M1.

7. The line voltage power failure detection circuit according to claim 1, characterized in that, The battery management module (6) includes a battery and a battery charging control unit. The power input terminal of the battery charging control unit is connected to the power output terminal of the transformer power supply module (1). The power output terminal of the battery charging control unit is connected to the power input terminal of the battery. The power output terminal of the battery is connected to the first conducting terminal of the second switch control module (5). The signal input terminal of the battery charging control unit is connected to the third signal output terminal of the main power switch module (2).

8. The line voltage power failure detection circuit according to claim 1, characterized in that, 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 mains 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 terminal 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. The power output terminal of the secondary winding Ls is connected to the signal acquisition terminal of the power failure detection module (3).

9. A line voltage power failure 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 for a line voltage power failure detection circuit, applied to a line voltage power failure detection circuit as described in any one of claims 1-9, characterized in that, The detection method includes: Obtain the minimum power supply voltage required for charging, as well as the input power supply voltage. Compare the minimum power supply voltage required for charging with the input power supply voltage. If the input power supply voltage is greater than the minimum power supply voltage required for charging, the first switch control module is 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 is less than the minimum power supply voltage required for charging, the first switch control module is turned off and the second switch control module is turned on, 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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