Protection circuit of voltage stabilizer and voltage stabilizer

Abstract

The utility model provides a protection circuit of a voltage stabilizer and the voltage stabilizer. The protection circuit comprises an NAND gate module, a first diode, a second diode, a switching tube and a first switch, the first input end of the NAND gate module is used for inputting a voltage stabilizer failure signal, the second input end of the NAND gate module is used for inputting a voltage stabilizer over-temperature alarm signal, and the output end of the NAND gate module is connected with the positive electrode of the first diode; the positive electrode of the second diode is used for inputting a voltage stabilizer overload protection signal, and the negative electrode of the second diode is connected with the negative electrode of the first diode and the control end of the switching tube; the first end of the switch tube is connected with the control end of the first switch, and the second end of the switch tube is grounded; the first end of the first switch is grounded, and the second end of the first switch is connected with at least one of the control end of the input switch and the control end of the output switch. According to the utility model, artificial participation is not needed, the real-time performance is high, and device damage caused by untimely protection can be avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of voltage stabilization, and in particular relates to a protection circuit of a voltage stabilizer and a voltage stabilizer. Background Art

[0002] A voltage stabilizer is an electrical device that adjusts and controls the voltage. Within a specified voltage input range, the voltage can be adjusted to stabilize the output voltage within a specified range. A voltage stabilizer can be used in the bypass of an uninterruptible power supply, stabilizing the input mains voltage and outputting a bypass power supply that meets the voltage accuracy.

[0003] When the voltage regulator fails or is abnormal, the bypass needs to be disconnected to avoid device damage or facilitate maintenance. At present, when the voltage regulator fails or is abnormal, the bypass is manually disconnected. This method requires manual participation and has poor real-time performance, which can easily cause device damage. Utility Model Content

[0004] In view of this, the embodiments of the present invention provide a protection circuit for a voltage stabilizer and a voltage stabilizer to solve the problem that the existing method requires manual participation and has poor real-time performance, which easily leads to device damage.

[0005] A first aspect of an embodiment of the utility model provides a protection circuit of a voltage stabilizer, wherein the voltage stabilizer is connected to an input power supply through an input switch, and the voltage stabilizer is connected to a load through an output switch;

[0006] The protection circuit of the voltage stabilizer includes a NAND gate module, a first diode, a second diode, a switch tube and a first switch;

[0007] The first input end of the NAND gate module is used to input a voltage regulator failure signal, the second input end of the NAND gate module is used to input a voltage regulator over-temperature alarm signal, and the output end of the NAND gate module is connected to the positive electrode of the first diode;

[0008] The anode of the second diode is used to input the voltage regulator overload protection signal, and the cathode of the second diode is connected to the cathode of the first diode and the control end of the switch tube respectively;

[0009] The first end of the switch tube is connected to the control end of the first switch, and the second end of the switch tube is grounded; the first end of the first switch is grounded, and the second end of the first switch is connected to at least one of the control end of the input switch and the control end of the output switch.

[0010] In some possible implementations, the NAND gate module includes a NAND gate, a first resistor, a second resistor, and a third resistor;

[0011] The first input end of the NAND gate is connected to the first end of the first resistor and the first end of the second resistor respectively; the second end of the first resistor is connected to the first input end of the NAND gate module, and the second end of the second resistor is used to connect to the first voltage terminal; the second input end of the NAND gate is connected to the second input end of the NAND gate module; the output end of the NAND gate is connected to the output end of the NAND gate module through the third resistor.

[0012] In some possible implementations, the protection circuit of the voltage regulator further includes an isolation filter module;

[0013] The input end of the isolation filter module is connected to the cathode of the first diode and the cathode of the second diode respectively, and the output end of the isolation filter module is connected to the control end of the switch tube.

[0014] In some possible implementations, the isolation filtering module includes a first comparator, a first capacitor, and a fourth resistor;

[0015] The first input end of the first comparator is connected to the input end of the isolation filter module, and the first input end of the first comparator is also grounded through a first capacitor and a fourth resistor connected in parallel; the second input end of the first comparator is used to connect to the second voltage terminal, and the output end of the first comparator is connected to the output end of the isolation filter module.

[0016] In some possible implementations, the protection circuit of the voltage regulator further includes a delay module;

[0017] The input end of the delay module is connected to the cathode of the first diode and the cathode of the second diode respectively, and the output end of the delay module is connected to the control end of the switch tube.

[0018] In some possible implementations, the delay module includes a second comparator, a second capacitor, a third diode, a fifth resistor, and a sixth resistor;

[0019] The first input end of the second comparator is respectively connected to the first end of the fifth resistor, the first end of the sixth resistor, the anode of the third diode and the anode of the second capacitor, the second input end of the second comparator is used to connect the second voltage terminal, and the output end of the second comparator is connected to the output end of the delay module;

[0020] The second end of the fifth resistor is connected to the input end of the delay module; the second end of the sixth resistor and the cathode of the third diode are both used to connect to the first voltage terminal; the negative electrode of the second capacitor is grounded.

[0021] In some possible implementations, the second end of the first switch is connected to the control end of the output switch.

[0022] In some possible implementations, the first switch includes a relay;

[0023] A first end of the coil of the relay is connected to the control end of the first switch, a second end of the coil of the relay is used to connect to the third voltage terminal, a first switch contact of the relay is connected to the first end of the first switch, and a second switch contact of the relay is connected to the second end of the first switch;

[0024] When the coil of the relay is energized, the first switch contact of the relay and the second switch contact of the relay are in a closed state.

[0025] In some possible implementations, the protection circuit of the voltage regulator further includes a fourth diode;

[0026] An anode of the fourth diode is connected to the control end of the first switch, and a cathode of the fourth diode is used to connect to the third voltage terminal.

[0027] A second aspect of an embodiment of the utility model provides a voltage stabilizer, comprising a protection circuit of the voltage stabilizer as described in the first aspect or any possible implementation manner of the first aspect.

[0028] The protection circuit of the voltage stabilizer provided in this embodiment includes a NAND gate module, a first diode, a second diode, a switch tube and a first switch; an "OR" logic circuit of three input signals is constructed by the NAND gate module, the first diode and the second diode, that is, when at least one of the voltage stabilizer failure signal, the voltage stabilizer overtemperature alarm signal and the voltage stabilizer overload protection signal is valid, the output signal of the "OR" logic circuit can turn on the switch tube, thereby closing the first switch, and then disconnecting at least one of the input switch and the output switch, so that the voltage stabilizer can achieve trip protection without manual intervention, and has high real-time performance, which can avoid device damage caused by untimely protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0030] Figure 1 The structure of the protection circuit of the voltage stabilizer provided by the embodiment of the utility model is shown in FIG. Figure 1 ;

[0031] Figure 2 The structure of the protection circuit of the voltage stabilizer provided by the embodiment of the utility model is shown in FIG. Figure 2 ;

[0032] Figure 3 The structure of the protection circuit of the voltage stabilizer provided by the embodiment of the utility model is shown in FIG. Figure 3;

[0033] Figure 4 The structure of the protection circuit of the voltage stabilizer provided by the embodiment of the utility model is shown in FIG. Figure 4 ;

[0034] Figure 5 It is a structural schematic diagram of a voltage stabilizer provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0035] In the following description, specific details such as specific system structures and technologies are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details that hinder the description of the present invention.

[0036] In order to illustrate the technical solution of the present utility model, specific embodiments are provided below for illustration.

[0037] See also Figure 1 , the embodiment of the utility model provides a protection circuit of a voltage stabilizer, wherein the voltage stabilizer is connected to an input power supply through an input switch S1, and the voltage stabilizer is connected to a load through an output switch S2;

[0038] The protection circuit of the voltage stabilizer includes a NAND gate module 21, a first diode D1, a second diode D2, a switch tube Q1 and a first switch K1;

[0039] The first input end of the NAND gate module 21 is used to input the voltage regulator failure signal INPUT1, the second input end of the NAND gate module 21 is used to input the voltage regulator over-temperature alarm signal INPUT2, and the output end of the NAND gate module 21 is connected to the positive electrode of the first diode D1;

[0040] The anode of the second diode D2 is used to input the voltage regulator overload protection signal INPUT3, and the cathode of the second diode D2 is connected to the cathode of the first diode D1 and the control end of the switch tube Q1 respectively;

[0041] The first end of the switch tube Q1 is connected to the control end of the first switch K1, and the second end of the switch tube Q1 is grounded (0V); the first end of the first switch K1 is grounded, and the second end of the first switch K1 is connected to at least one of the control end of the input switch S1 and the control end of the output switch S2.

[0042] The NAND gate module 21, the first diode D1 and the second diode D2 form an "OR" logic circuit. The voltage regulator failure signal INPUT1, the voltage regulator over-temperature alarm signal INPUT2 and the voltage regulator overload protection signal INPUT3 are three input signals of the above "OR" logic circuit. When at least one input signal is valid, it means that the voltage regulator can no longer serve as a stable bypass voltage regulator. In order to protect the load, the bypass should be disconnected. At this time, the above "OR" logic circuit outputs a high level, thereby controlling the switch tube Q1 to turn on. After the switch tube Q1 is turned on, the first switch K1 is energized and closed, thereby controlling at least one of the input switch S1 and the output switch S2 to be disconnected, thereby realizing the trip protection of the voltage regulator.

[0043] When the above three input signals are all invalid, the above "OR" logic circuit outputs a low level, the switch tube Q1 remains disconnected, the first switch K1 is not powered and remains disconnected, and then the input switch S1 and the output switch S2 are both in a normally closed state, and the voltage regulator works normally.

[0044] When the voltage regulator fails, the voltage regulator failure signal INPUT1 is valid. When the voltage regulator is not failed and can work normally, the voltage regulator failure signal INPUT1 is invalid. Among them, the voltage regulator failure usually means that the input voltage of the voltage regulator is normal but the output voltage accuracy is abnormal. The cause of the failure is usually the abnormal compensation circuit of the voltage regulator or the abnormal control signal. The compensation circuit involves the compensation transformer and thyristor, which cannot be repaired under power. The control signal involves the control board and the driver board, which also cannot be directly repaired under power, so it is necessary to control the voltage regulator to trip the protection.

[0045] When the operating temperature of the device in the voltage regulator (such as a transformer or thyristor, etc.) is too high (for example, higher than the set temperature), the voltage regulator over-temperature alarm signal INPUT2 is valid. When the operating temperature of the devices in the voltage regulator is within the normal temperature range (for example, not higher than the set temperature), the voltage regulator over-temperature alarm signal INPUT2 is invalid. When the operating temperature of the device in the voltage regulator is too high, in order to avoid damage to the device, it is necessary to reduce the load in time or disconnect the input switch S1 or the output switch S2. As the reaction of the machine itself cannot consider the external load, it is necessary to disconnect the input switch S1 or the output switch S2 to protect the device in the voltage regulator from over-temperature damage.

[0046] When the regulator is overloaded, the regulator overload protection signal INPUT3 is valid, and when the regulator is not overloaded, the regulator overload protection signal INPUT3 is invalid. The regulator overload may also cause the device to overheat, and it cannot be recovered by timely load reduction, so it is also necessary to disconnect the input switch S1 or the output switch S2 to protect the components in the regulator from damage.

[0047] In this embodiment, when at least one of the above three input signals is valid, the protection circuit of the voltage regulator can protect the voltage regulator by disconnecting the input switch S1, or by disconnecting the output switch S2, or by simultaneously disconnecting the input switch S1 and the output switch S2.

[0048] Among them, the input switch S1 and the output switch S2 can both be circuit breakers or other types of switches, which are not specifically limited here. The switch tube Q1 can be a MOS tube or other types of switch tubes Q1, which are not specifically limited here. The first switch K1 can be a relay or a contactor, or other types of switches, which are not specifically limited here. The power supply end of the first switch K1 is used to connect the third voltage terminal V3, and the third voltage terminal V3 can provide a 12V voltage.

[0049] The protection circuit of the voltage regulator provided in this embodiment includes a NAND gate module 21, a first diode D1, a second diode D2, a switch tube Q1 and a first switch K1; an "OR" logic circuit of three input signals is constructed by the NAND gate module 21, the first diode D1 and the second diode D2, that is, when at least one of the voltage regulator failure signal INPUT1, the voltage regulator overtemperature alarm signal INPUT2 and the voltage regulator overload protection signal INPUT3 is valid, the output signal of the "OR" logic circuit can turn on the switch tube Q1, thereby closing the first switch K1, and then disconnecting at least one of the input switch S1 and the output switch S2, so that the voltage regulator can achieve trip protection without manual intervention, and has high real-time performance, which can avoid device damage caused by untimely protection.

[0050] In some embodiments, see Figure 1 , the NAND gate module 21 includes a NAND gate IC1, a first resistor R1, a second resistor R2 and a third resistor R3;

[0051] The first input end of the NAND gate IC1 is connected to the first end of the first resistor R1 and the first end of the second resistor R2 respectively; the second end of the first resistor R1 is connected to the first input end of the NAND gate module 21, and the second end of the second resistor R2 is used to connect to the first voltage terminal V1; the second input end of the NAND gate IC1 is connected to the second input end of the NAND gate module 21; the output end of the NAND gate IC1 is connected to the output end of the NAND gate module 21 through the third resistor R3.

[0052] The first voltage terminal V1 can provide a voltage of 15V.

[0053] In some embodiments, see Figure 2 , the protection circuit of the voltage stabilizer also includes an isolation filter module 22;

[0054] The input end of the isolation filter module 22 is connected to the cathode of the first diode D1 and the cathode of the second diode D2 respectively, and the output end of the isolation filter module 22 is connected to the control end of the switch tube Q1.

[0055] The input and output of the isolation filter module 22 are consistent. When the input is at a high level, the output is also at a high level, and when the input is at a low level, the output is also at a low level.

[0056] The isolation and filtering module 22 can isolate and filter the signals output by the first diode D1 and the second diode D2 to make the signals more stable and accurate.

[0057] In some embodiments, see Figure 2 , the isolation filter module 22 includes a first comparator IC2, a first capacitor C1 and a fourth resistor R4;

[0058] The first input end of the first comparator IC2 is connected to the input end of the isolation filter module 22, and the first input end of the first comparator IC2 is also grounded through the first capacitor C1 and the fourth resistor R4 connected in parallel; the second input end of the first comparator IC2 is used to connect the second voltage terminal V2, and the output end of the first comparator IC2 is connected to the output end of the isolation filter module 22.

[0059] The second voltage terminal V2 can provide a voltage of 7.5V.

[0060] In some possible implementations, see Figure 2 , the second voltage terminal V2 can be grounded through the third capacitor C3.

[0061] In some embodiments, see Figure 3 , the protection circuit of the voltage stabilizer also includes a delay module 23;

[0062] The input end of the delay module 23 is connected to the cathode of the first diode D1 and the cathode of the second diode D2 respectively, and the output end of the delay module 23 is connected to the control end of the switch tube Q1.

[0063] In this embodiment, the delay module 23 can transmit the output signal of the “OR” logic circuit to the control end of the switch tube Q1 after delaying for a preset time.

[0064] The purpose of the delay is to prevent the whole machine power-on alarm information from being falsely reported. In the event of a false alarm, the voltage regulator is not immediately controlled to trip to avoid false tripping. At the same time, the fault signal can be recorded.

[0065] Exemplarily, when at least one of the regulator failure signal INPUT1, the regulator over-temperature alarm signal INPUT2 and the regulator overload protection signal INPUT3 is valid, if it is only valid for a moment, the input switch S1 and the output switch S2 will not be controlled to be disconnected. If the effective time exceeds the above preset time, the input switch S1 or the output switch S2 will be controlled to be disconnected, thereby avoiding false alarms that cause the regulator to trip incorrectly.

[0066] In some embodiments, see Figure 3 , the delay module 23 includes a second comparator IC3, a second capacitor C2, a third diode D3, a fifth resistor R5 and a sixth resistor R6;

[0067] The first input end of the second comparator IC3 is respectively connected to the first end of the fifth resistor R5, the first end of the sixth resistor R6, the anode of the third diode D3 and the anode of the second capacitor C2, the second input end of the second comparator IC3 is used to connect the second voltage terminal V2, and the output end of the second comparator IC3 is connected to the output end of the delay module 23;

[0068] The second end of the fifth resistor R5 is connected to the input end of the delay module 23; the second end of the sixth resistor R6 and the cathode of the third diode D3 are both used to connect to the first voltage terminal V1; the negative electrode of the second capacitor C2 is grounded.

[0069] The second capacitor C2 may be a charging and discharging capacitor.

[0070] The delay module 23 of this embodiment not only has a delay function, but also can play a filtering role.

[0071] In some possible implementations, see Figure 4 , the protection circuit of the voltage stabilizer may also include an isolation filter module 22 and a delay module 23;

[0072] The input end of the isolation filter module 22 is connected to the cathode of the first diode D1 and the cathode of the second diode D2 respectively, the output end of the isolation filter module 22 is connected to the input end of the delay module 23, and the output end of the delay module 23 is connected to the control end of the switch tube Q1.

[0073] In some embodiments, the second terminal of the first switch K1 is connected to the control terminal of the output switch S2 .

[0074] In this embodiment, the second end of the first switch K1 is preferably connected to the control end of the output switch S2, that is, when any of the voltage regulator failure signal INPUT1, the voltage regulator over-temperature alarm signal INPUT2 and the voltage regulator overload protection signal INPUT3 is valid, the output switch S2 is controlled to be disconnected. When the output switch S2 is disconnected and the input switch S1 is still closed, the voltage regulator still has input, and can still maintain the working state, and continuously monitor, so as to facilitate the subsequent judgment of whether a fault or abnormality occurs, etc. At the same time, when the voltage regulator returns to normal, the output switch S2 is controlled to be closed, so that the voltage regulator can quickly enter the normal working state.

[0075] In some embodiments, the first switch K1 comprises a relay;

[0076] A first end of the coil of the relay is connected to the control end of the first switch K1, a second end of the coil of the relay is used to connect to the third voltage terminal V3, a first switch contact of the relay is connected to the first end of the first switch K1, and a second switch contact of the relay is connected to the second end of the first switch K1;

[0077] When the coil of the relay is energized, the first switch contact of the relay and the second switch contact of the relay are in a closed state.

[0078] In this embodiment, the relay is in a normally open state, and is in a closed state only after the coil is energized.

[0079] In some embodiments, see Figure 4 , the protection circuit of the voltage regulator also includes a fourth diode D4;

[0080] An anode of the fourth diode D4 is connected to the control end of the first switch K1 , and a cathode of the fourth diode D4 is used to connect to the third voltage terminal V3 .

[0081] In some possible implementations, see Figure 4 The protection circuit of the voltage regulator further includes a ninth resistor R9 and a light emitting diode D6 connected in series; after the ninth resistor R9 and the light emitting diode D6 are connected in series, they are connected in parallel with the fourth diode D4.

[0082] The light emitting diode D6 can be used as an indicator light. When the voltage stabilizer is protected, the light emitting diode D6 emits light. When the voltage stabilizer is not protected, the light emitting diode D6 does not emit light.

[0083] In some possible implementations, see Figure 4 The protection circuit of the voltage regulator also includes a fifth capacitor C5 and an eighth resistor R8 connected in parallel; the fifth capacitor C5 and the eighth resistor R8 are both connected between the control end of the switch tube Q1 and the second end of the switch tube Q1.

[0084] In some possible implementations, see Figure 4 The protection circuit of the voltage regulator also includes a fifth diode and a seventh resistor R7; the first end of the seventh resistor R7 is used to connect to the first voltage terminal V1, the second end of the seventh resistor R7 and the positive electrode of the fifth diode are both connected to the output end of the delay module 23, and the cathode of the fifth diode is used to connect to the power-on blocking signal FS.

[0085] The power-on blocking signal FS is used to block the protection circuit of the voltage regulator. When the power-on blocking signal FS is valid, no matter whether the three input signals are valid or not, the tripping protection of the output switch S2 and the input switch S1 will not be triggered.

[0086] In some possible implementations, see Figure 4 , the protection circuit of the voltage stabilizer further includes a first connection terminal CN1; the input switch S1 includes a first release, and the output switch S2 includes a second release;

[0087] A first end of the first connection terminal CN1 is connected to a second end of the first switch K1, and a second end of the first connection terminal CN1 is used to connect to a fourth voltage terminal V4;

[0088] The first end of the coil of the first release is connected to the first end of the first connection terminal CN1, and the second end of the coil of the first release is connected to the second end of the first connection terminal CN1; and / or, the first end of the coil of the second release is connected to the first end of the first connection terminal CN1, and the second end of the coil of the second release is connected to the second end of the first connection terminal CN1.

[0089] When the first switch K1 is closed, the coils of the first release and / or the second release are energized, thereby driving the input switch S1 and / or the output switch S2 to be disconnected. The first release and the second release may be shunt releases. The fourth voltage terminal V4 may provide a voltage of 24V.

[0090] In some possible implementations, see Figure 4 , the protection circuit of the voltage regulator further includes a fourth capacitor C4 connected in parallel with the first connection terminal CN1.

[0091] In some possible implementations, see Figure 4 The protection circuit of the voltage regulator further includes a second connection terminal CN2 and a third connection terminal CN3 connected in parallel with the first connection terminal CN1.

[0092] When the voltage stabilizer is a three-phase voltage stabilizer, the switch of each phase is respectively connected to a connection terminal.

[0093] It should be noted that the voltage provided by each voltage terminal in this application can be set according to actual use requirements, and the voltages provided by each voltage terminal given in this application are only examples. The grounding of each device in this application can be the same ground or different grounds, which can be set according to actual needs.

[0094] In some possible implementations, the structure of the voltage regulator is as follows: Figure 5 As shown, it may include a compensation voltage stabilizer and a regulating circuit composed of devices such as thyristors for regulating the compensation voltage, etc. Figure 5 This is just an example of a voltage regulator, and the voltage regulator may also have other structures, which are not specifically limited here.

[0095] Corresponding to the protection circuit of the above-mentioned voltage stabilizer, an embodiment of the utility model provides a voltage stabilizer, including the protection circuit of any of the above-mentioned voltage stabilizers, and having the beneficial effects of the protection circuit of any of the above-mentioned voltage stabilizers.

[0096] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A protection circuit for a voltage stabilizer, characterized in that: The voltage stabilizer is connected to an input power source via an input switch, and the voltage stabilizer is connected to a load via an output switch; The protection circuit of the voltage stabilizer comprises a NAND gate module, a first diode, a second diode, a switch tube and a first switch; The first input end of the NAND gate module is used to input a voltage regulator failure signal, the second input end of the NAND gate module is used to input a voltage regulator over-temperature alarm signal, and the output end of the NAND gate module is connected to the positive electrode of the first diode; The anode of the second diode is used to input the voltage regulator overload protection signal, and the cathode of the second diode is connected to the cathode of the first diode and the control end of the switch tube respectively; The first end of the switch tube is connected to the control end of the first switch, and the second end of the switch tube is grounded; the first end of the first switch is grounded, and the second end of the first switch is connected to at least one of the control end of the input switch and the control end of the output switch.

2. The protection circuit of the voltage stabilizer according to claim 1, characterized in that: The NAND gate module includes a NAND gate, a first resistor, a second resistor and a third resistor; The first input end of the NAND gate is connected to the first end of the first resistor and the first end of the second resistor respectively; the second end of the first resistor is connected to the first input end of the NAND gate module, and the second end of the second resistor is used to connect to the first voltage terminal; the second input end of the NAND gate is connected to the second input end of the NAND gate module; the output end of the NAND gate is connected to the output end of the NAND gate module through the third resistor.

3. The protection circuit of the voltage stabilizer according to claim 1, characterized in that: The protection circuit of the voltage stabilizer also includes an isolation filter module; The input end of the isolation filter module is connected to the cathode of the first diode and the cathode of the second diode respectively, and the output end of the isolation filter module is connected to the control end of the switch tube.

4. The protection circuit of the voltage regulator according to claim 3, characterized in that: The isolation filtering module includes a first comparator, a first capacitor and a fourth resistor; The first input end of the first comparator is connected to the input end of the isolation filtering module, and the first input end of the first comparator is also grounded through the first capacitor and the fourth resistor connected in parallel; the second input end of the first comparator is used to connect to the second voltage terminal, and the output end of the first comparator is connected to the output end of the isolation filtering module.

5. The protection circuit of the voltage stabilizer according to claim 1, characterized in that: The protection circuit of the voltage stabilizer also includes a delay module; The input end of the delay module is connected to the cathode of the first diode and the cathode of the second diode respectively, and the output end of the delay module is connected to the control end of the switch tube.

6. The protection circuit of the voltage regulator according to claim 5, characterized in that: The delay module includes a second comparator, a second capacitor, a third diode, a fifth resistor and a sixth resistor; The first input end of the second comparator is respectively connected to the first end of the fifth resistor, the first end of the sixth resistor, the anode of the third diode and the anode of the second capacitor, the second input end of the second comparator is used to connect to the second voltage terminal, and the output end of the second comparator is connected to the output end of the delay module; The second end of the fifth resistor is connected to the input end of the delay module; the second end of the sixth resistor and the cathode of the third diode are both used to connect to the first voltage terminal; the negative electrode of the second capacitor is grounded.

7. The protection circuit of the voltage regulator according to claim 1, characterized in that: The second end of the first switch is connected to the control end of the output switch.

8. The protection circuit of the voltage regulator according to claim 1, characterized in that: The first switch includes a relay; A first end of the coil of the relay is connected to the control end of the first switch, a second end of the coil of the relay is used to connect to the third voltage terminal, a first switch contact of the relay is connected to the first end of the first switch, and a second switch contact of the relay is connected to the second end of the first switch; When the coil of the relay is energized, the first switch contact of the relay and the second switch contact of the relay are in a closed state.

9. The protection circuit of the voltage regulator according to claim 1, characterized in that: The protection circuit of the voltage stabilizer further includes a fourth diode; An anode of the fourth diode is connected to the control end of the first switch, and a cathode of the fourth diode is used to connect to a third voltage terminal.

10. A voltage stabilizer, characterized in that: A protection circuit comprising the voltage regulator as claimed in any one of claims 1 to 9.

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