Alternating-current overvoltage and undervoltage multi-protection circuit

Abstract

The invention provides an alternating-current overvoltage and undervoltage multi-protection circuit, which can ensure that functions of overvoltage protection, undervoltage protection and the like can be realized in a switching process of two power supplies of 220V alternating current and a 24V storage battery, ensure that alternating-current power supply can be quickly switched into direct-current power supply of the storage battery, and ensure a normal power supply effect. The invention relates to a timing reset self-locking circuit, which comprises a power supply circuit, an alternating current over-voltage / under-voltage protection circuit, a direct current over-voltage / under-voltage protection circuit, a self-locking circuit, a timing reset self-locking circuit and a signal control circuit, and the alternating current over-voltage / under-voltage protection circuit is connected with the direct current over-voltage / under-voltage protection circuit and then respectively connected with the self-locking circuit and the timing reset self-locking circuit. And the self-locking circuit and the timing reset self-locking circuit are connected with the signal control circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply protection circuits, and in particular to an AC overvoltage and undervoltage multiple protection circuit. Background Art

[0002] At present, network equipment, monitoring equipment, etc. are all powered by 220V AC. If the 220V AC stops supplying power, the devices connected to it will not work. In order to solve this problem, a dual power design is generally adopted, that is, one circuit is powered by 220V AC and the other circuit is powered by 24V battery. In the process of using dual power design, the following situations may occur: when 220V AC and 24V battery are connected at the same time, 220V AC is given priority, and the 24V battery is cut off at this time to reduce the standby loss of the battery; when the 220V AC is over-voltage, under-voltage or power failure, the power supply can quickly switch to 24V battery power supply to achieve secondary continuous DC power supply output; when the 220V AC resumes normal power supply, the 24V battery delays working for a few seconds to ensure that the 220V AC works normally, and then the 24V battery stops working. Since the above-mentioned different situations may occur during the use of dual power supplies, it is urgently necessary to provide a protection circuit to ensure that overvoltage protection, undervoltage protection and other functions can be realized during the switching of the two power supplies, and to ensure that the AC power supply can be quickly switched to the battery DC power supply to ensure normal power supply effect. Summary of the invention

[0003] In view of the need to provide a protection circuit to prevent power supply abnormalities in the existing dual-power supply process, the present invention provides an AC overvoltage and undervoltage multiple protection circuit, which can ensure that during the switching process of the two power sources of 220V AC and 24V battery, overvoltage protection, undervoltage protection and other functions can be implemented, ensuring that the AC power supply can be quickly switched to the battery DC power supply to ensure normal power supply effect.

[0004] The technical solution is as follows: an AC overvoltage and undervoltage multiple protection circuit, characterized in that: it includes a power supply circuit, an AC overvoltage / undervoltage protection circuit, a DC overvoltage / undervoltage protection circuit, a self-locking circuit, a timer reset self-locking circuit and a signal control circuit, the AC overvoltage / undervoltage protection circuit is connected to the DC overvoltage / undervoltage protection circuit and then connected to the self-locking circuit and the timer reset self-locking circuit respectively, and the self-locking circuit and the timer reset self-locking circuit are further connected to the signal control circuit; The input end of the power supply circuit is connected to an AC 220V input voltage, which is converted into a 5V or 2.5V voltage source by a voltage stabilizer; The AC overvoltage / undervoltage protection circuit is used to detect whether the AC 220V input voltage is abnormal; The DC overvoltage / undervoltage protection circuit is used to detect whether the DC high voltage 400V input voltage is abnormal; The self-locking circuit is used to lock the state of the overvoltage and undervoltage protection circuit, and the protection circuit is the AC overvoltage / undervoltage protection circuit or the DC overvoltage / undervoltage protection circuit, so as to facilitate the subsequent signal processing by the timing reset self-locking circuit; The timing reset self-locking circuit is used to reset the self-locking circuit in time when overvoltage or undervoltage occurs; The signal control circuit sends a control signal to the external 24V battery power circuit according to the conditions of the aforementioned circuits to control the operation of the 24V battery power circuit.

[0005] Its further feature is that: the power supply circuit includes a voltage stabilizer U1, the 5th to 8th pins of the voltage stabilizer U1 are connected and then connected to one end of a resistor R1, the other end of the resistor R1 is connected to the cathode of a diode D1 and the cathode of a diode D2, the anode of the diode D1 is connected to the cathode of a diode D4 and the live wire L1 of an AC 220V input voltage, the anode of the diode D2 is connected to the cathode of a diode D5 and the neutral wire N1 of an AC 220V input voltage, the anode of the diode D4 is connected to the anode of the diode D5 and then grounded, and the Pin 3 of the voltage regulator U1 is connected to one end of the capacitor C2, one end of the capacitor C3, and one end of the resistor R2, and outputs a 5V voltage source. The other end of the resistor R2 is connected to pins 1 and 2 of the voltage regulator diode U2 and one end of the capacitor C4, and outputs a 2.5V voltage source. Pin 4 of the voltage regulator U1 is connected to one end of the capacitor C1 and outputs a 7.5V voltage source. The other end of the capacitor C1 is connected to pin 2 of the voltage regulator U1, the other end of the capacitor C2, the other end of the capacitor C3, pin 3 of the voltage regulator diode U2, the other end of the capacitor C4, and grounded. The AC overvoltage / undervoltage protection circuit includes operational amplifiers U6, U4A, U4B, U5A, and U5B. The positive input terminal 1 of the operational amplifier U6 is connected to one end of a resistor R10, the negative electrode of a voltage regulator tube D7, one end of a resistor R15, and one end of a capacitor C7. The other end of the resistor R10 is connected to the power supply circuit through resistors R6 and 7 in sequence. The positive electrode of the voltage regulator tube D7, the other end of the resistor R15, and the other end of the capacitor C7 are connected to pin 2 of the operational amplifier U6 and then grounded. The inverting input terminal 3 of the operational amplifier U6 is connected to the output terminal 4 and then connected to the inverting input terminal 6 of the operational amplifier U4B and the inverting input terminal 2 of the operational amplifier U4A. The output terminal 7 of the operational amplifier U4B is connected to the output terminal 4 of the operational amplifier U6. The pin is connected to the non-inverting input terminal 5 pin of the operational amplifier U5B and one end of the resistor R11, the other end of the resistor R11 is connected to one end of the capacitor C6, the collector of the transistor U7B, and the DC overvoltage / undervoltage protection circuit, the emitter of the transistor U7B is connected to one end of the resistor R13 and the base of the transistor U7A, the other end of the resistor R13 is connected to the cathode of the diode D6, the anode of the diode D6 is connected to the emitter of the transistor U7A and a 5V voltage source, the collector of the transistor U7A is connected to the base of the transistor U7B and one end of the resistor R14, the other end of the resistor R14 is connected to the other end of the capacitor C6, the 4th pin of the operational amplifier U4A and grounded, the operational amplifier U Pin 7 of the operational amplifier U5B is connected to one end of the resistor R8, pin 1 of the operational amplifier U5A is connected to one end of the resistor R35 and one end of the resistor R17, the other end of the resistor R35 is connected to pin 8 of the operational amplifier U5A and then connected to a 5V voltage source, the other end of the resistor R17 is connected to the other end of the resistor R8 and then connected to the self-locking circuit, the positive phase input pin 3 of the operational amplifier U4B is connected to one end of the resistor R20, one end of the resistor R23, and one end of the capacitor C8, the other end of the resistor R20 is connected to a 2.5V voltage source, the output pin 1 of the operational amplifier U4A is connected to the positive phase input pin 2 of the operational amplifier U5A and one end of the resistor R21, the other end of the resistor R21 is connected to one end of the capacitor C9 and the transistor U9B The collector, the emitter of the transistor U9B is connected to one end of the resistor R22 and the base of the transistor U91, the other end of the resistor R22 is connected to the cathode of the diode D10, the anode of the diode D10 is connected to the emitter of the transistor U9A and then connected to a 5V voltage source, the collector of the transistor U9A is connected to the base of the transistor U9B and one end of the resistor R27, the other end of the resistor R27 is connected to the other end of the capacitor C9, the other end of the capacitor C8, the other end of the resistor R23 and grounded, the positive input terminal 5 pin of the operational amplifier U4B, the inverting input terminal 6 pin of the operational amplifier U5B, and the positive input terminal 3 pin of the operational amplifier U5A are respectively connected to a 2.5V voltage source; The DC overvoltage / undervoltage protection circuit comprises an op amp U12, an op amp U10A, and an op amp U10B. The positive input terminal 1 pin of the op amp U12 is connected to one end of the capacitor C13, one end of the resistor R37, the negative electrode of the diode D12, and one end of the resistor R30. The other end of the resistor R30 is connected to a 400V voltage source through resistors R28 and R26. The inverting input terminal 3 pin of the op amp U12 is connected to the output terminal 4 pin and then connected to the inverting input terminal 6 pin of the op amp U10B and the inverting input terminal 3 pin of the op amp U10A. The pin 2 of the op amp U10A is connected to one end of the resistor R31, one end of the resistor R34, one end of the capacitor C12, and a 2.13V voltage source. The other end of the resistor R31 is connected to Connect to a 2.5V voltage source, the positive electrode of the diode D12 is connected to the other end of the resistor R37, the other end of the capacitor C13, the 2nd pin of the operational amplifier U12, the other end of the resistor R34, the other end of the capacitor C12, the 4th pin of the operational amplifier U10A and grounded, the output terminal 7th pin of the operational amplifier U10B is connected to one end of the resistor R24, the other end of the resistor 24 is connected to the AC overvoltage / undervoltage protection circuit, the output terminal 1st pin of the operational amplifier U10A is connected to one end of the resistor R35 and one end of the resistor R38, the other end of the resistor R35 is connected to the 8th pin of the operational amplifier U10A and the 5V voltage source, and the other end of the resistor R38 is connected to the self-locking circuit and the timing reset self-locking circuit; The self-locking circuit includes transistors Q2 and Q4, the collector of the transistor Q4 is connected to one end of the resistor R16 and the positive electrode of the diode D9B, the negative electrode of the diode D9B is connected to the AC overvoltage / undervoltage protection circuit, the DC overvoltage / undervoltage protection circuit, and the timing reset self-locking circuit, the emitter of the transistor Q4 is connected to one end of the resistor R25 and grounded, the base of the transistor Q4 is connected to one end of the resistor R19, the other end of the resistor R25, and the timing reset self-locking circuit, the other end of the resistor R19 is connected to the collector of the transistor Q2 and the signal control circuit, the base of the transistor Q2 is connected to one end of the capacitor C5, one end of the resistor R12, and the other end of the resistor R16, and the emitter of the transistor Q2 is connected to the other end of the capacitor C5, the other end of the resistor R12 and a 5V voltage source; The timing reset self-locking circuit includes an operational amplifier U8A, wherein the positive input terminal pin 3 of the operational amplifier U8A is connected to a 2.5V voltage source, the inverting input terminal pin 2 of the operational amplifier U8A is connected to the positive electrode of a diode D9A, the positive electrode of a diode D8, and one end of a resistor R29, the negative electrode of the diode D9A is connected to the AC overvoltage / undervoltage protection circuit, the DC overvoltage / undervoltage protection circuit, and the self-locking circuit, the negative electrode of the diode D8 is connected to the signal control circuit, the output terminal pin 1 of the operational amplifier U8A is connected to the self-locking circuit, and the other end of the resistor R29 is connected to one end of a resistor R33 and a capacitor C10, one end of capacitor C11, the other end of the resistor R33 is connected to the collector of transistor U11B, the other end of the capacitor C10 is connected to the other end of the capacitor C11, one end of the resistor R36 and grounded, the base of the transistor U11B is connected to the other end of the resistor R36 and the collector of the transistor U11A, the emitter of the transistor U11B is connected to the base of the transistor U11A and one end of the resistor R32, the other end of the resistor R32 is connected to the cathode of the diode D11, the anode of the diode D11 is connected to the emitter of the transistor U11A and connected to a 5V voltage source; The signal control circuit includes an operational amplifier U8B, wherein the positive input terminal 5 pin of the operational amplifier U8B is connected to the self-locking circuit, the inverting input terminal 6 pin of the operational amplifier U8B is connected to a 2.5V voltage source, the output terminal 7 pin of the operational amplifier U8B is connected to one end of a resistor R9, the base of a transistor Q3, and one end of a resistor R18, the other end of the resistor R18 is connected to the emitter of the transistor Q3 and then grounded, the collector of the transistor Q3 is connected to pin 2 of the optocoupler U3, the other end of the resistor R9 is connected to one end of the resistor R3 and a 5V voltage source, the other end of the resistor R3 is connected to pin 1 of the optocoupler U3, the 3rd pin of the optocoupler U3 is connected to the emitter of the transistor Q1, the 4th pin of the optocoupler U3 is connected to the cathode of a diode D3 and one end of a resistor R5, the anode of the diode D3 is connected to the base of the transistor Q1, and the other end of the resistor R5 is grounded.

[0006] After adopting the above structure, through the setting of AC overvoltage / undervoltage protection circuit and DC overvoltage / undervoltage protection circuit, when the AC 220V input voltage and the DC high voltage 400V input voltage have overvoltage or undervoltage abnormalities, the abnormal signal can be sent to the self-locking circuit to lock, and the timed reset self-locking circuit is used to reset the self-locking circuit in time when overvoltage or undervoltage occurs. Finally, according to the power supply abnormality of the aforementioned circuit including the AC overvoltage / undervoltage protection circuit, the DC overvoltage / undervoltage protection circuit, the self-locking circuit, and the timed reset self-locking circuit, the signal control circuit will send a control signal to the external 24V battery power supply circuit to control the operation of the 24V battery power supply circuit, so that when the 220V AC power has overvoltage or undervoltage abnormalities, the AC power supply can be quickly switched to the battery DC power supply to ensure the normal power supply effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is the overall circuit principle diagram of the present invention; Figure 2 A circuit schematic diagram of the power supply circuit of the present invention; Figure 3 The circuit schematic diagram of the AC overvoltage / undervoltage protection circuit of the present invention; Figure 4 The circuit schematic diagram of the DC overvoltage / undervoltage protection circuit of the present invention; Figure 5 It is a circuit principle diagram of the self-locking circuit of the present invention; Figure 6 It is a circuit principle diagram of the timing reset self-locking circuit of the present invention; Figure 7 4 is a circuit schematic diagram of the signal control circuit of the present invention. DETAILED DESCRIPTION

[0008] like Figure 1 As shown, an AC overvoltage and undervoltage multiple protection circuit includes a power supply circuit, an AC overvoltage / undervoltage protection circuit, a DC overvoltage / undervoltage protection circuit, a self-locking circuit, a timer reset self-locking circuit and a signal control circuit. After the AC overvoltage / undervoltage protection circuit is connected to the DC overvoltage / undervoltage protection circuit, the self-locking circuit and the timer reset self-locking circuit are respectively connected. The self-locking circuit and the timer reset self-locking circuit are then connected to the signal control circuit. The input end of the power supply circuit is connected to the AC 220V input voltage, which is converted into 5V and 2.5V voltage sources by the voltage stabilizer, and the 5V and 2.5V voltage sources converted and output by the power supply module are used to provide internal power supply for other circuits of the present invention, thereby improving the portability of use; The AC overvoltage / undervoltage protection circuit is used to detect whether the AC 220V input voltage has overvoltage or undervoltage abnormalities; The DC overvoltage / undervoltage protection circuit is used to detect whether the DC high voltage 400V input voltage has overvoltage or undervoltage anomalies, wherein the DC high voltage 400V is the DC high voltage output by the PFC power factor compensation circuit of the AC 220V input voltage; The self-locking circuit is used to lock the state of the overvoltage and undervoltage protection circuit, which is an AC overvoltage / undervoltage protection circuit or a DC overvoltage / undervoltage protection circuit, so as to facilitate the subsequent timing reset of the self-locking circuit for signal processing; The timed reset self-locking circuit is used to reset the self-locking circuit in time when overvoltage or undervoltage occurs; The signal control circuit sends a control signal to the external 24V battery power circuit according to the conditions of the other aforementioned circuits, so that when the AC 220V input voltage or the DC high voltage 400V input voltage has a power supply abnormality, the 24V battery power circuit is controlled to work to ensure normal power supply.

[0009] like Figure 2 As shown, the power supply circuit includes a voltage regulator U1. The voltage regulator U1 can choose to use an SSP7786A-5.0V chip, and the input AC voltage range of the chip is 80Vac~305Vac. The specific circuit is as follows: pins 5 to 8 of the voltage regulator U1 are connected and then connected to one end of the resistor R1, the other end of the resistor R1 is connected to the cathode of the diode D1 and the cathode of the diode D2, the anode of the diode D1 is connected to the cathode of the diode D4 and the live wire L1 of the AC 220V input voltage, the anode of the diode D2 is connected to the cathode of the diode D5 and the neutral wire N1 of the AC 220V input voltage, the anode of the diode D4 is connected to the anode of the diode D5 and then grounded, pin 3 of the voltage regulator U1 is connected to one end of the capacitor C2, one end of the capacitor C3, and one end of the resistor R2 and outputs a 5V voltage source, the other end of the resistor R2 is connected to pins 1 and 2 of the voltage regulator diode U2, and one end of the capacitor C4 and outputs a 2.5V voltage source, pin 4 of the voltage regulator U1 is connected to one end of the capacitor C1 and outputs a 7.5V voltage source, the other end of the capacitor C1 is connected to pin 2 of the voltage regulator U1, the other end of the capacitor C2, the other end of the capacitor C3, pin 3 of the voltage regulator diode U2, the other end of the capacitor C4 and grounded. The working principle of this power supply circuit is: the AC power is rectified into "M" waveform DC power through diodes D1, D2, D4, and D5, and a stable +5V power supply is obtained through resistor R1, voltage regulator U1, capacitors C1, C2, and C3. +5V is passed through resistor R2, capacitor C4, and diode U2 (model: TL431B) to obtain a reference voltage of +2.5V.

[0010] The AC voltage over / under voltage detection circuit is used to detect the working condition of the AC 220V input voltage. When an abnormality occurs, it can generate an abnormal signal to control other circuits. Figure 3As shown, the AC overvoltage / undervoltage protection circuit includes operational amplifiers U6, U4A, U4B, U5A, and U5B. The positive input terminal 1 of the operational amplifier U6 is connected to one end of the resistor R10, the negative electrode of the voltage regulator tube D7, one end of the resistor R15, and one end of the capacitor C7. The other end of the resistor R10 is connected to the power supply circuit through the resistor R6 and the resistor 7 in sequence. The positive electrode of the voltage regulator tube D7, the other end of the resistor R15, and the other end of the capacitor C7 are connected to the 2nd pin of the operational amplifier U6 and then grounded. The inverting input terminal 3rd pin of the operational amplifier U6 is connected to the output terminal 4th pin and then connected to the inverting input terminal 6th pin of the operational amplifier U4B and the inverting input terminal 2nd pin of the operational amplifier U4A. The output terminal 7-pin is connected to the non-inverting input terminal 5-pin of the operational amplifier U5B and one end of the resistor R11. The other end of the resistor R11 is connected to one end of the capacitor C6, the collector of the transistor U7B, and the DC overvoltage / undervoltage protection circuit. The emitter of the transistor U7B is connected to one end of the resistor R13 and the base of the transistor U7A. The other end of the resistor R13 is connected to the cathode of the diode D6. The anode of the diode D6 is connected to the emitter of the transistor U7A and the 5V voltage source. The collector of the transistor U7A is connected to the base of the transistor U7B and one end of the resistor R14. The other end of the resistor R14 is connected to the other end of the capacitor C6, the 4-pin of the operational amplifier U4A and grounded. Pin 7 of U5B is connected to one end of resistor R8, pin 1 of op amp U5A is connected to one end of resistor R35 and one end of resistor R17, the other end of resistor R35 is connected to pin 8 of op amp U5A and then to a 5V voltage source, the other end of resistor R17 is connected to the other end of resistor R8 and then to a self-locking circuit, pin 3 of the positive input terminal of op amp U4B is connected to one end of resistor R20, one end of resistor R23, and one end of capacitor C8, the other end of resistor R20 is connected to a 2.5V voltage source, pin 1 of the output terminal of op amp U4A is connected to pin 2 of the positive input terminal of op amp U5A and one end of resistor R21, the other end of resistor R21 is connected to one end of capacitor C9 and transistor U9 The collector of transistor U9A is connected to the collector of transistor B, the emitter of transistor U9B is connected to one end of resistor R22 and the base of transistor U91, the other end of resistor R22 is connected to the cathode of diode D10, the anode of diode D10 is connected to the emitter of transistor U9A and then connected to a 5V voltage source, the collector of transistor U9A is connected to the base of transistor U9B and one end of resistor R27, the other end of resistor R27 is connected to the other end of capacitor C9, the other end of capacitor C8, the other end of resistor R23 and grounded, the non-inverting input terminal 5 pin of op amp U4B, the inverting input terminal 6 pin of op amp U5B, and the non-inverting input terminal 3 pin of op amp U5A are respectively connected to 2.5V voltage sources.

[0011] The working principle of the AC voltage over / under voltage detection circuit is as follows: The AC power is rectified into an "M" shaped DC waveform by the power supply module. The DC voltage waveform is divided by resistors R6, R7, R10, and R15 to obtain a low-voltage voltage signal "AC_DET". The voltage regulator D7 is used to prevent input overvoltage, and the capacitor C7 is a filter capacitor. The low-voltage signal "AC_DET" is followed by the operational amplifier U6 (model: LM321) to obtain the signal "AC_Follow". The operational amplifiers U4A, U5A and their peripheral circuits constitute an undervoltage detection circuit. In the undervoltage detection circuit, the signal "AC_Follow" is compared with +1.34V through the operational amplifier U4A (model: LMV393). When the voltage of the signal "AC_Follow" is lower than +1.34V, the diode D10, transistors U9A and U9B, resistors R22 and R27, and capacitor C9 form a current source to charge the capacitor C9. The charging time is related to the value of the capacitor C9. The charging time is generally set to be greater than 15mS (greater than the frequency 47*2Hz after rectification). The longer the setting time is, the longer the undervoltage detection time is. The charging voltage "AC_UV_DET" of the capacitor C9 and the reference voltage +2.5V are compared through the operational amplifier U5. A (model: LMV393) is compared: if the maximum voltage of the signal "AC_Follow" is lower than +1.34V and the undervoltage detection time exceeds the set value, the signal "AC_UVP" becomes low level, and the common terminal signal "UV_OV_COM" is low level; if the maximum voltage of the signal "AC_Follow" is greater than +1.34V and the detection time does not exceed the set value, the signal "AC_UV_DET" will have a chance to become high level, and the charge of capacitor C9 will be quickly discharged through resistor R21. The discharge speed of capacitor C9 is much faster than the charging speed, and the charge of capacitor C19 is basically discharged. The signal "AC_UVP" becomes high level, and the common terminal signal "UV_OV_COM" is high level; Among them, the operational amplifiers U4B, U5B and their peripheral circuits constitute an overvoltage detection circuit. In the overvoltage detection circuit, when the signal "AC_Follow" voltage enters, the capacitor C6 is fully charged due to the current source composed of diode D6, transistors U7A and U7B, resistors R13 and R14, and capacitor C6. The signal "AC_Follow" voltage is compared with the reference voltage +2.5V through the comparator U4B (model: LMV393). The signal "AC_Follow" voltage is higher than +2.5V, and the signal "AC_OV_DET" becomes a low level. The capacitor C6 starts to discharge. The discharge time of the capacitor C6 is related to the capacitance of the capacitor C6 and the resistance of the resistor R11. The discharge time is generally set to be greater than 30mS (greater than the frequency of 47*2Hz after rectification, and taking into account the lightning overvoltage). The longer the setting time, the longer the overvoltage detection time. When the maximum voltage of the signal "AC_Follow" is higher than +2.5V and the discharge time exceeds the set value, the voltage of capacitor C6 after discharge is compared with the reference voltage +2.5V through comparator U5B (model: LMV393), the signal "AC_OVP" becomes low, and the common terminal signal "UV_OV_COM" is low. If the maximum voltage of the signal "AC_Follow" is less than +2.5V and the detection time does not exceed the set value, the signal "AC_OV_DET" becomes high, the capacitor C6 stops discharging and is always in the charging state. When the charging voltage of capacitor C6 is higher than +2.5V, the signal "AC_OVP" becomes high, and the common terminal signal "UV_OV_COM" is high.

[0012] The DC overvoltage / undervoltage protection circuit is used to detect whether the DC high voltage 400V input voltage is abnormal. Figure 4As shown, the DC overvoltage / undervoltage protection circuit includes op amp U12, op amp U10A, and op amp U10B. Pin 1 of the positive input terminal of op amp U12 is connected to one end of capacitor C13, one end of resistor R37, the negative electrode of diode D12, and one end of resistor R30. The other end of resistor R30 is connected to a 400V voltage source through resistors R28 and R26. Pin 3 of the inverting input terminal of op amp U12 is connected to pin 4 of the output terminal and then to pin 6 of the inverting input terminal of op amp U10B and pin 3 of the inverting input terminal of op amp U10A. Pin 2 of op amp U10A is connected to one end of resistor R31, one end of resistor R34, one end of capacitor C12, and a 2.13V voltage source. The other end of resistor R31 is connected to a 2.5V voltage source, the positive electrode of diode D12 is connected to the other end of resistor R37, the other end of capacitor C13, pin 2 of op amp U12, the other end of resistor R34, the other end of capacitor C12, pin 4 of op amp U10A and grounded, pin 7 of output terminal of op amp U10B is connected to one end of resistor R24, the other end of resistor 24 is connected to the AC overvoltage / undervoltage protection circuit, pin 1 of output terminal of op amp U10A is connected to one end of resistor R35 and one end of resistor R38, the other end of resistor R35 is connected to pin 8 of op amp U10A and a 5V voltage source, and the other end of resistor R38 is connected to the self-locking circuit and the timer reset self-locking circuit.

[0013] The working principle of the DC high voltage over-voltage and under-voltage detection circuit is as follows: When the DC high voltage 400V input voltage is abnormal, it can generate an abnormal signal to control other circuits and DC high voltage over-voltage and under-voltage detection circuits. Figure 4 As shown, the DC high voltage 400V input voltage is divided by resistors R26, R28, R30, and R37 to obtain a low voltage signal "HV_DET". The voltage regulator D12 is used to prevent input overvoltage, and the capacitor C13 is a filter capacitor. The low voltage signal "HV_DET" is followed by the operational amplifier (model: LM321) U12 to obtain a signal "HV_Follow", and the signal "HV_Follow" is sent to the overvoltage and undervoltage comparison circuit for processing; When the signal "HV_Follow" voltage enters the undervoltage detection circuit, the signal "HV_Follow" voltage is compared with the voltage +2.13V obtained by the voltage division of resistors R31 and R34 through the comparator U10A (model: LMV393). When the signal "HV_Follow" voltage is lower than +2.13V, the signal "HV_UVP" becomes a low level, and the common terminal signal "UV_OV_COM" is a low level. If the "HV_Follow" voltage value is greater than +2.13V, the signal "HV_UVP" becomes a high level, and the common terminal signal "UV_OV_COM" is a high level; When the "HV_Follow" voltage enters the overvoltage detection circuit, the capacitor C6 is fully charged due to the current source composed of diode D6, transistors U7A and U7B, resistors R13 and R14, and capacitor C6. The signal "HV_Follow" voltage is compared with the reference voltage +2.5V through comparator U10B (model: LMV393). When the "HV_Follow" voltage is higher than +2.5V, the discharge time is related to the value of capacitor C6 and resistor R24. The discharge time is generally set to be greater than 1mS. The longer the setting time, the longer the overvoltage detection time. The maximum value of the signal "HV_Follow" voltage is higher than +2.5V and the discharge time exceeds the set value. The voltage of capacitor C6 after discharge is compared with the reference voltage +2.5V through comparator U5B (model: LMV393), and the signal "AC_OVP" becomes low level, and the common terminal signal "UV_OV_COM" is low level. If the maximum voltage of the signal "HV_Follow" is less than +2.5V, the signal "HV_OVP" becomes high level, the capacitor C9 stops discharging and remains in a charging state. When the charging voltage of the capacitor C6 is higher than +2.5V, the signal "AC_OVP" becomes high level, and the common terminal signal "UV_OV_COM" is high level.

[0014] Specifically, Figure 5 As shown, the self-locking circuit includes transistors Q2 and Q4, the collector of the transistor Q4 is connected to one end of the resistor R16 and the positive electrode of the diode D9B, the negative electrode of the diode D9B is connected to the AC overvoltage / undervoltage protection circuit, the DC overvoltage / undervoltage protection circuit, and the timing reset self-locking circuit, the emitter of the transistor Q4 is connected to one end of the resistor R25 and grounded, the base of the transistor Q4 is connected to one end of the resistor R19, the other end of the resistor R25, and the timing reset self-locking circuit, the other end of the resistor R19 is connected to the collector of the transistor Q2 and the signal control circuit, the base of the transistor Q2 is connected to one end of the capacitor C5, one end of the resistor R12, and the other end of the resistor R16, and the emitter of the transistor Q2 is connected to the other end of the capacitor C5, the other end of the resistor R12 and a 5V voltage source.

[0015] The specific working principle of the self-locking circuit is as follows: When the "UV_OV_COM" signal is at a high level, the diode D9B is in the off state, the transistors Q2 and Q4 are in the off state, and the "Lock_Self" signal is at a low level. When the "UV_OV_COM" signal changes from a high level to a low level, the diode D9B changes from off to instantaneously on, and then changes to the off state, the transistors Q2 and Q4 change from off to on, and the "Lock_Self" signal changes from a low level to a high level. When the "UV_OV_COM" signal changes from a low level to a high level, the diode D9B is in the off state, the transistors Q2 and Q4 are still in the on state, and the "Lock_Self" signal is still at a high level, which realizes low-level trigger locking, and the "Lock_Self" signal is used for subsequent signal processing.

[0016] The timed reset self-locking circuit is used for the timed reset of the overvoltage and undervoltage self-locking circuits. Figure 6 As shown, the timing reset self-locking circuit includes an operational amplifier U8A, the positive input terminal 3 pin of the operational amplifier U8A is connected to a 2.5V voltage source, the inverting input terminal 2 pin of the operational amplifier U8A is connected to the positive electrode of the diode D9A, the positive electrode of the diode D8, and one end of the resistor R29, the cathode of the diode D9A is connected to the AC overvoltage / undervoltage protection circuit, the DC overvoltage / undervoltage protection circuit, and the self-locking circuit, the cathode of the diode D8 is connected to the signal control circuit, the output terminal 1 pin of the operational amplifier U8A is connected to the self-locking circuit, the other end of the resistor R29 is connected to one end of the resistor R33, the One end of the capacitor C10 and one end of the capacitor C11, the other end of the resistor R33 is connected to the collector of the transistor U11B, the other end of the capacitor C10 is connected to the other end of the capacitor C11 and one end of the resistor R36 and is grounded, the base of the transistor U11B is connected to the other end of the resistor R36 and the collector of the transistor U11A, the emitter of the transistor U11B is connected to the base of the transistor U11A and one end of the resistor R32, the other end of the resistor R32 is connected to the cathode of the diode D11, the anode of the diode D11 is connected to the emitter of the transistor U11A and is connected to a 5V voltage source; The working principle of the timing reset self-locking circuit is as follows: The timing reset self-locking circuit is used for timing reset of overvoltage and undervoltage self-locking circuits. Figure 6As shown. Diode D11, resistors R32, R33 and R36, transistors U11A / U11B, capacitors C10 and C11 form a current source to charge capacitors C10 and C11. The charging time is determined by the capacitance of capacitors C10 and C11. When the AC voltage and DC high voltage voltage change from normal working state to overvoltage or undervoltage, the "UV_OV_COM" signal changes from high level to low level, and capacitors C10 and C11 are discharged through resistor R29 and diode D8 and then discharged through resistor R29 and diode D9A. The two discharge speeds are much greater than the charging speed. The voltage across capacitor C10 is always less than +2.5V, and the self-locking circuit cannot be reset. At this time, since the transistor Q3 in the signal control circuit is turned off, the diode D8 is also turned off. When the AC voltage or DC voltage changes from abnormal to normal, the "UV_OV_COM" signal changes from low level to high level. At this time, diodes D8 and D9A are all turned off. At this time, capacitors C10 and C11 are in a charging state. The charging voltage of capacitor C10 is compared with the reference voltage +2.5V through comparator U8A (model: LMV393). When the voltage of charging capacitor C10 exceeds +2.5V, the "UV_OV_RST" signal is low level. At this time, transistor Q4 in the self-locking circuit is in the off state, the "UV_OV_COM" signal is high level, diode D9B is turned off, transistor Q2 is in the off state, and the "Lock_Self" signal changes from high level to low level to reset the self-locking circuit.

[0017] The signal control circuit sends a control signal to the external 24V battery circuit according to the abnormal conditions of the aforementioned circuits to control whether it works, wherein the aforementioned circuits include an AC overvoltage / undervoltage protection circuit, a DC overvoltage / undervoltage protection circuit, a self-locking circuit and a timed reset self-locking circuit. Specifically, Figure 7 As shown, the signal control circuit includes an operational amplifier U8B, wherein the positive input terminal 5 pin of the operational amplifier U8B is connected to the self-locking circuit, the inverting input terminal 6 pin of the operational amplifier U8B is connected to a 2.5V voltage source, the output terminal 7 pin of the operational amplifier U8B is connected to one end of a resistor R9, the base of a transistor Q3, and one end of a resistor R18, the other end of the resistor R18 is connected to the emitter of the transistor Q3 and then grounded, the collector of the transistor Q3 is connected to pin 2 of an optocoupler U3, the other end of the resistor R9 is connected to one end of a resistor R3 and a 5V voltage source, the other end of the resistor R3 is connected to pin 1 of the optocoupler U3, the 3rd pin of the optocoupler U3 is connected to the emitter of the transistor Q1, the 4th pin of the optocoupler U3 is connected to the cathode of a diode D3 and one end of a resistor R5, the anode of the diode D3 is connected to the base of the transistor Q1, and the other end of the resistor R5 is grounded.

[0018] The working principle of the signal control circuit is as follows: The self-locking circuit signal "Lock_Self" is compared with the reference voltage +2.5V through the comparator U8B (model: LMV393). When the signal "Lock_Self" is low, the signal "UV_OV_CTRL" is low, the transistor Q3 is turned off, the signal "OPT_CTRL" is high, the optocoupler U3 does not work, the transistor Q1 is turned on, and the signal "DC_CTRL" has a voltage output. When the signal "Lock_Self" is high, the signal "UV_OV_CTRL" is high, the transistor Q3 is turned on, the signal "OPT_CTRL" is low, the optocoupler U3 works normally, the transistor Q1 is turned off, and the signal "DC_CTRL" has no voltage output.

[0019] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by anyone familiar with the technology within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An AC overvoltage and undervoltage multiple protection circuit, characterized in that: It includes a power supply circuit, an AC overvoltage / undervoltage protection circuit, a DC overvoltage / undervoltage protection circuit, a self-locking circuit, a timer reset self-locking circuit and a signal control circuit. The AC overvoltage / undervoltage protection circuit is connected to the DC overvoltage / undervoltage protection circuit and then connected to the self-locking circuit and the timer reset self-locking circuit respectively. The self-locking circuit and the timer reset self-locking circuit are then connected to the signal control circuit. The input end of the power supply circuit is connected to an AC 220V input voltage, which is converted into a 5V or 2.5V voltage source by a voltage stabilizer; The AC overvoltage / undervoltage protection circuit is used to detect whether the AC 220V input voltage is abnormal; The DC overvoltage / undervoltage protection circuit is used to detect whether the DC high voltage 400V input voltage is abnormal; The self-locking circuit is used to lock the state of the overvoltage and undervoltage protection circuit, and the protection circuit is the AC overvoltage / undervoltage protection circuit or the DC overvoltage / undervoltage protection circuit, so as to facilitate the subsequent signal processing by the timing reset self-locking circuit; The timing reset self-locking circuit is used to reset the self-locking circuit in time when overvoltage or undervoltage occurs; The signal control circuit sends a control signal to the external 24V battery power circuit according to the conditions of the aforementioned circuits to control the operation of the 24V battery power circuit.

2. The AC overvoltage and undervoltage multiple protection circuit according to claim 1, characterized in that: The power supply circuit includes a voltage stabilizer U1, wherein pins 5 to 8 of the voltage stabilizer U1 are connected to one end of a resistor R1, the other end of the resistor R1 is connected to the cathode of a diode D1 and the cathode of a diode D2, the anode of the diode D1 is connected to the cathode of a diode D4 and the live wire L1 of an AC 220V input voltage, the anode of the diode D2 is connected to the cathode of a diode D5 and the neutral wire N1 of an AC 220V input voltage, the anode of the diode D4 is connected to the anode of the diode D5 and then grounded, and the voltage stabilizer U1 Pin 3 is connected to one end of capacitor C2, one end of capacitor C3, and one end of resistor R2 and outputs a 5V voltage source. The other end of resistor R2 is connected to pins 1 and 2 of voltage regulator diode U2 and one end of capacitor C4 and outputs a 2.5V voltage source. Pin 4 of voltage regulator U1 is connected to one end of capacitor C1 and outputs a 7.5V voltage source. The other end of capacitor C1 is connected to pin 2 of voltage regulator U1, the other end of capacitor C2, the other end of capacitor C3, pin 3 of voltage regulator diode U2, the other end of capacitor C4 and grounded.

3. The AC overvoltage and undervoltage multiple protection circuit according to claim 1, characterized in that: The AC overvoltage / undervoltage protection circuit includes operational amplifiers U6, U4A, U4B, U5A, and U5B. The positive input terminal 1 of the operational amplifier U6 is connected to one end of a resistor R10, the negative electrode of a voltage regulator tube D7, one end of a resistor R15, and one end of a capacitor C7. The other end of the resistor R10 is connected to the power supply circuit through resistors R6 and 7 in sequence. The positive electrode of the voltage regulator tube D7, the other end of the resistor R15, and the other end of the capacitor C7 are connected to pin 2 of the operational amplifier U6 and then grounded. The inverting input terminal 3 of the operational amplifier U6 is connected to the output terminal 4 and then connected to the inverting input terminal 6 of the operational amplifier U4B and the inverting input terminal 2 of the operational amplifier U4A. The output terminal 7 of the operational amplifier U4B is connected to the output terminal 4 of the operational amplifier U6. The pin is connected to the non-inverting input terminal 5 pin of the operational amplifier U5B and one end of the resistor R11, the other end of the resistor R11 is connected to one end of the capacitor C6, the collector of the transistor U7B, and the DC overvoltage / undervoltage protection circuit, the emitter of the transistor U7B is connected to one end of the resistor R13 and the base of the transistor U7A, the other end of the resistor R13 is connected to the cathode of the diode D6, the anode of the diode D6 is connected to the emitter of the transistor U7A and a 5V voltage source, the collector of the transistor U7A is connected to the base of the transistor U7B and one end of the resistor R14, the other end of the resistor R14 is connected to the other end of the capacitor C6, the 4th pin of the operational amplifier U4A and grounded, the operational amplifier U Pin 7 of the operational amplifier U5B is connected to one end of the resistor R8, pin 1 of the operational amplifier U5A is connected to one end of the resistor R35 and one end of the resistor R17, the other end of the resistor R35 is connected to pin 8 of the operational amplifier U5A and then connected to a 5V voltage source, the other end of the resistor R17 is connected to the other end of the resistor R8 and then connected to the self-locking circuit, the positive phase input pin 3 of the operational amplifier U4B is connected to one end of the resistor R20, one end of the resistor R23, and one end of the capacitor C8, the other end of the resistor R20 is connected to a 2.5V voltage source, the output pin 1 of the operational amplifier U4A is connected to the positive phase input pin 2 of the operational amplifier U5A and one end of the resistor R21, the other end of the resistor R21 is connected to one end of the capacitor C9 and the transistor U9B The collector, the emitter of the transistor U9B is connected to one end of the resistor R22 and the base of the transistor U91, the other end of the resistor R22 is connected to the cathode of the diode D10, the anode of the diode D10 is connected to the emitter of the transistor U9A and then connected to a 5V voltage source, the collector of the transistor U9A is connected to the base of the transistor U9B and one end of the resistor R27, the other end of the resistor R27 is connected to the other end of the capacitor C9, the other end of the capacitor C8, the other end of the resistor R23 and grounded, the positive input terminal 5 pin of the operational amplifier U4B, the inverting input terminal 6 pin of the operational amplifier U5B, and the positive input terminal 3 pin of the operational amplifier U5A are respectively connected to a 2.5V voltage source.

4. The AC overvoltage and undervoltage multiple protection circuit according to claim 1, characterized in that: The DC overvoltage / undervoltage protection circuit comprises an op amp U12, an op amp U10A, and an op amp U10B. The positive input terminal 1 pin of the op amp U12 is connected to one end of the capacitor C13, one end of the resistor R37, the negative electrode of the diode D12, and one end of the resistor R30. The other end of the resistor R30 is connected to a 400V voltage source through resistors R28 and R26. The inverting input terminal 3 pin of the op amp U12 is connected to the output terminal 4 pin and then connected to the inverting input terminal 6 pin of the op amp U10B and the inverting input terminal 3 pin of the op amp U10A. The pin 2 of the op amp U10A is connected to one end of the resistor R31, one end of the resistor R34, one end of the capacitor C12, and a 2.13V voltage source. The other end of the resistor R31 is connected to A 2.5V voltage source is connected, the positive electrode of the diode D12 is connected to the other end of the resistor R37, the other end of the capacitor C13, pin 2 of the operational amplifier U12, the other end of the resistor R34, the other end of the capacitor C12, pin 4 of the operational amplifier U10A and grounded, the output pin 7 of the operational amplifier U10B is connected to one end of the resistor R24, the other end of the resistor 24 is connected to the AC overvoltage / undervoltage protection circuit, the output pin 1 of the operational amplifier U10A is connected to one end of the resistor R35 and one end of the resistor R38, the other end of the resistor R35 is connected to pin 8 of the operational amplifier U10A and a 5V voltage source, and the other end of the resistor R38 is connected to the self-locking circuit and the timing reset self-locking circuit.

5. The AC overvoltage and undervoltage multiple protection circuit according to claim 1, characterized in that: The self-locking circuit includes transistors Q2 and Q4, the collector of the transistor Q4 is connected to one end of the resistor R16 and the positive electrode of the diode D9B, the negative electrode of the diode D9B is connected to the AC overvoltage / undervoltage protection circuit, the DC overvoltage / undervoltage protection circuit, and the timing reset self-locking circuit, the emitter of the transistor Q4 is connected to one end of the resistor R25 and is grounded, the base of the transistor Q4 is connected to one end of the resistor R19, the other end of the resistor R25, and the timing reset self-locking circuit, the other end of the resistor R19 is connected to the collector of the transistor Q2 and the signal control circuit, the base of the transistor Q2 is connected to one end of the capacitor C5, one end of the resistor R12, and the other end of the resistor R16, and the emitter of the transistor Q2 is connected to the other end of the capacitor C5, the other end of the resistor R12 and a 5V voltage source.

6. The AC overvoltage and undervoltage multiple protection circuit according to claim 1, characterized in that: The timing reset self-locking circuit includes an operational amplifier U8A, wherein the positive input terminal pin 3 of the operational amplifier U8A is connected to a 2.5V voltage source, the inverting input terminal pin 2 of the operational amplifier U8A is connected to the positive electrode of a diode D9A, the positive electrode of a diode D8, and one end of a resistor R29, the negative electrode of the diode D9A is connected to the AC overvoltage / undervoltage protection circuit, the DC overvoltage / undervoltage protection circuit, and the self-locking circuit, the negative electrode of the diode D8 is connected to the signal control circuit, the output terminal pin 1 of the operational amplifier U8A is connected to the self-locking circuit, and the other end of the resistor R29 is connected to one end of a resistor R33 and a capacitor C10 and one end of capacitor C11, the other end of the resistor R33 is connected to the collector of the transistor U11B, the other end of the capacitor C10 is connected to the other end of the capacitor C11 and one end of the resistor R36 and is grounded, the base of the transistor U11B is connected to the other end of the resistor R36 and the collector of the transistor U11A, the emitter of the transistor U11B is connected to the base of the transistor U11A and one end of the resistor R32, the other end of the resistor R32 is connected to the cathode of the diode D11, the anode of the diode D11 is connected to the emitter of the transistor U11A and is connected to a 5V voltage source.

7. The AC overvoltage and undervoltage multiple protection circuit according to claim 1, characterized in that: The signal control circuit includes an operational amplifier U8B, wherein the positive input terminal 5 pin of the operational amplifier U8B is connected to the self-locking circuit, the inverting input terminal 6 pin of the operational amplifier U8B is connected to a 2.5V voltage source, the output terminal 7 pin of the operational amplifier U8B is connected to one end of a resistor R9, the base of a transistor Q3, and one end of a resistor R18, the other end of the resistor R18 is connected to the emitter of the transistor Q3 and then grounded, the collector of the transistor Q3 is connected to pin 2 of the optocoupler U3, the other end of the resistor R9 is connected to one end of the resistor R3 and a 5V voltage source, the other end of the resistor R3 is connected to pin 1 of the optocoupler U3, the 3rd pin of the optocoupler U3 is connected to the emitter of the transistor Q1, the 4th pin of the optocoupler U3 is connected to the cathode of a diode D3 and one end of a resistor R5, the anode of the diode D3 is connected to the base of the transistor Q1, and the other end of the resistor R5 is grounded.

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