A hierarchical shutdown circuit and electrical equipment using the same

Abstract

The present invention discloses a hierarchical shutdown circuit and an electrical device using the same, comprising: a trigger signal generating module, wherein the input end of the trigger signal generating module is connected to an external control signal to generate a trigger signal according to the external control signal; a superposition module, wherein the first input end of the superposition module is connected to the output end of the trigger signal generating module, the second input end of the superposition module is connected to the external control signal, the superposition module superimposes the trigger signal and the external control signal to form a pre-shutdown portion on the external control signal, and then converts it into a hierarchical shutdown signal; the output end of the superposition module is connected to the control end of an external power switch tube. By superimposing the trigger signal and the external control signal through the superposition module to form a pre-shutdown portion on the external control signal, and then converting it into a hierarchical shutdown signal, the hierarchical shutdown effect is achieved, the magnitude of the spike voltage generated by the shutdown can be reduced, and it is beneficial to protect the components in the circuit and improve reliability.

Description

Technical Field

[0001] The present invention relates to the field of power switch tube control, and in particular to a hierarchical shutdown circuit and electrical equipment using the same. Background Art

[0002] Power switches are crucial components in modern electronics, widely used in various power control and conversion circuits, such as inverters. However, when a power switch is turned off, it generates a voltage spike, which can affect and even damage the switch and other components in the circuit. This is especially true for power switches used in power devices such as high-voltage inverters and reactive power compensation devices, where voltage spikes must be suppressed for stable operation.

[0003] In the existing technology, the following solutions are commonly used to suppress spike voltages: 1. Reducing the busbar's stray inductance; 2. Adding a snubber capacitor; 3. Adding an active clamping circuit. However, reducing the busbar's stray inductance in solution 1 increases material costs and can only reduce the spike voltage to a threshold value. The actual power switch still experiences significant spike voltages during operation. Solution 2, which adds a snubber capacitor, can easily lead to voltage fluctuations and reduce circuit reliability. Solution 3, which adds an active clamping circuit, is expensive and requires the circuit to be as short as possible, otherwise achieving the desired function is difficult, which increases design complexity. Furthermore, when the busbar voltage exceeds the active clamping threshold voltage, the power switch will fail to shut down.

[0004] Since none of the above methods can effectively solve the spike voltage problem of power switch tubes, a new solution is currently being proposed: a staged shutdown method that gradually shuts down the power switch tubes to reduce the spike voltage. However, current technical methods do not have an efficient and feasible circuit structure for generating a staged shutdown signal. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a hierarchical shutdown circuit and an electrical device using the same. The circuit generates a trigger signal through a trigger signal generation module, and a superposition module processes an external control signal based on the trigger signal to form a hierarchical shutdown signal. The hierarchical shutdown signal controls the power switch tubes to achieve hierarchical shutdown, thereby reducing the peak voltage.

[0006] According to the first aspect of the present invention, a hierarchical shutdown circuit includes: a trigger signal generating module, the input end of the trigger signal generating module is connected to an external control signal to generate a trigger signal according to the external control signal; a superposition module, the first input end of the superposition module is connected to the output end of the trigger signal generating module, the second input end of the superposition module is connected to the external control signal, the superposition module superimposes the trigger signal and the external control signal to form a pre-shutdown part on the external control signal, and then converts it into a hierarchical shutdown signal, and the output end of the superposition module is connected to the control end of the external power switch tube.

[0007] A hierarchical shutdown circuit according to an embodiment of the present invention has at least the following beneficial effects: a trigger signal is generated by a trigger signal generation module, and a superposition module superimposes the trigger signal with an external control signal to form a pre-shutdown portion on the external control signal, which is then converted into a hierarchical shutdown signal output. Before completely shutting down the power switch tube, the hierarchical shutdown signal first controls the power switch tube to undergo a pre-shutdown process, thereby reducing the degree of conduction of the power switch tube, and then completely shutting down the power switch tube. With this structure, the hierarchical shutdown signal is generated to achieve the hierarchical shutdown effect, which can reduce the magnitude of the peak voltage generated by the shutdown, avoid the generation of a large peak voltage by a single shutdown, and thus help protect components in the circuit, maintain normal operation of the circuit, and improve reliability.

[0008] According to some embodiments of the present invention, the trigger signal generating module includes a delay unit and a comparison operation unit, the input end of the delay unit is connected to the external control signal, the first input end of the comparison operation unit is connected to the output end of the delay unit, the second input end of the comparison operation unit is connected to the external control signal, and the output end of the comparison operation unit is connected to the first input end of the superposition module.

[0009] According to some embodiments of the present invention, the delay unit includes a resistor R1 and a capacitor C1, one end of the resistor R1 is connected to an external control signal, the other end of the resistor R1 is respectively connected to one end of the capacitor C1 and the first input end of the comparison operation unit, and the other end of the capacitor C1 is grounded.

[0010] According to some embodiments of the present invention, the comparison operation unit includes an inverter U1 and a NOR gate U3, the input end of the inverter U1 is connected to the output end of the delay unit, the output end of the inverter U1 is connected to the first input end of the NOR gate U3, the second input end of the NOR gate U3 is connected to the output end of the delay unit, and the output end of the NOR gate U3 is connected to the first input end of the superposition module.

[0011] According to some embodiments of the present invention, the superposition module includes a switch tube U5, a resistor R6, a resistor R7 and a resistor R8; one end of the resistor R6 is connected to the output end of the delay unit, and the other end of the resistor R6 is respectively connected to one end of the resistor R8 and the control end of the external power switch tube; one end of the resistor R7 is connected to the output end of the NOR gate U3, and the other end of the resistor R7 is connected to the control end of the switch tube U5; the input end of the switch tube U5 is connected to the other end of the resistor R8, and the output end of the switch tube U5 is grounded.

[0012] According to some embodiments of the present invention, an inverter U2 is further included, wherein the input end of the inverter U2 is connected to the output end of the inverter U1, and the output end of the inverter U2 is connected to one end of the resistor R6. Both the inverter U1 and the inverter U2 are Schmitt inverters.

[0013] According to some embodiments of the present invention, a regulating module is further included, wherein the input end of the regulating module is connected to the output end of the superposition module to adjust the amplitude of the graded shutdown signal, and the output end of the regulating module is connected to the control end of the external power switch tube.

[0014] According to some embodiments of the present invention, the regulation module includes a switch tube U4, a resistor R9 and a resistor R10, the control end of the switch tube U4 is connected to the output end of the superposition module, the input end of the switch tube U4 is connected to the power supply end, the output end of the switch tube U4 is connected to one end of the resistor R9, the other end of the resistor R9 is respectively connected to one end of the resistor R10 and the control end of the external power switch tube, and the other end of the resistor R10 is grounded.

[0015] According to an embodiment of the second aspect of the present invention, an electrical device includes a power switch tube, a control module and the above-mentioned graded shutdown circuit, the output end of the control module is respectively connected to the trigger signal generating module and the input end of the superposition module, the output end of the superposition module is connected to the control end of the power switch tube, the input end of the power switch tube is connected to the power supply end, and the output end of the power switch tube is connected to the external load.

[0016] The electrical equipment according to embodiments of the present invention has at least the following beneficial effects: a control module generates a control signal and transmits it to the power switch via a graded shutdown circuit to control the on and off cycles of the power switch, thereby regulating the output power to meet the load's operating requirements. Furthermore, a trigger module generates a trigger signal, and a superposition module superimposes the trigger signal with the control signal to form a graded shutdown signal, which is then transmitted to the power switch to implement graded shutdown control. This effectively suppresses voltage spikes, preventing damage to circuit components caused by voltage spikes and improving reliability.

[0017] According to some embodiments of the present invention, the power switch tube is an IGBT, the collector of the IGBT is connected to the power supply end, the emitter of the IGBT is connected to the external load, and the gate of the IGBT is connected to the output end of the superposition module.

[0018] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which:

[0020] Figure 1 A circuit diagram of one embodiment of the present invention;

[0021] Figure 2 A circuit diagram showing one embodiment of the present invention connected to a waveform detector;

[0022] Figure 3 for Figure 2 Schematic diagram of the detection signal waveform of the medium waveform detector;

[0023] Figure 4 for Figure 2 Schematic diagram of the detection signal waveform of the waveform detector after changing the resistance value of resistor R8;

[0024] Figure 5 FIG. 1 is a schematic diagram of signal waveforms in actual testing according to one embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0026] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0027] In the description of the present invention, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0028] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0029] refer to Figure 1 and Figure 2 According to an embodiment of the present invention, a hierarchical shutdown circuit includes: a trigger signal generating module 200, wherein the input end of the trigger signal generating module 200 is connected to the external control signal to generate a trigger signal according to the external control signal; a superposition module 300, wherein the first input end of the superposition module 300 is connected to the output end of the trigger signal generating module 200, the second input end of the superposition module 300 is connected to the external control signal, the superposition module 300 processes the external control signal according to the trigger signal to form a hierarchical shutdown signal, and the output end of the superposition module 300 is connected to the control end of the external power switch tube 100.

[0030] The trigger signal generation module 200 generates a trigger signal, and the superposition module 300 superimposes the trigger signal with the external control signal to form a pre-shutdown portion on the external control signal, which is then converted into a graded shutdown signal output. Before controlling the power switch tube 100 to completely shut down, the graded shutdown signal first controls the power switch tube 100 to undergo a pre-shutdown process, namely reducing the degree of conduction of the power switch tube 100, and then completely shuts down the power switch tube 100. With this structure, the graded shutdown signal is generated to achieve the effect of graded shutdown, which can reduce the magnitude of the peak voltage generated by the shutdown and avoid the generation of a large peak voltage by a single shutdown. This helps protect the components in the circuit, maintain the normal operation of the circuit, and improve reliability.

[0031] Reference Figure 1 and Figure 2 In some embodiments of the present invention, the trigger signal generating module 200 includes a delay unit 210 and a comparison operation unit 220, the input end of the delay unit 210 is connected to the external control signal, the first input end of the comparison operation unit 220 is connected to the output end of the delay unit 210, the second input end of the comparison operation unit 220 is connected to the external control signal, and the output end of the comparison operation unit 220 is connected to the first input end of the superposition module 300.

[0032] The delay unit 210 delays the external control signal to generate a delay signal. The comparison operation unit 220 compares the external control signal and the delay signal. According to the shut-off moment of the external control signal and the shut-off moment of the delay signal, a trigger signal is generated in the interval between the two shut-off moments. The time point of the voltage mutation of the trigger signal generated in this way is associated with the shut-off moment of the external control signal and the shut-off moment of the delay signal, which is beneficial to the synchronization of the trigger signal with the external control signal and the delay signal, thereby improving the accuracy of control.

[0033] Reference Figure 1 and Figure 2 In some embodiments of the present invention, the delay unit 210 includes a resistor R1 and a capacitor C1, one end of the resistor R1 is connected to the external control signal, the other end of the resistor R1 is respectively connected to one end of the capacitor C1 and the first input end of the comparison operation unit 220, and the other end of the capacitor C1 is grounded.

[0034] The input external control signal is delayed by an RC delay circuit. The delay time can be adjusted by the resistance value of resistor R1 and the capacitance value of capacitor C1. The structure is simple, easy to implement, and low in cost. The delay unit 210 can also be a common delay circuit mainly composed of a delay relay, or other implementation methods.

[0035] Reference Figure 1 and Figure 2 In some embodiments of the present invention, the comparison operation unit 220 includes an inverter U1 and a NOR gate U3, the input end of the inverter U1 is connected to the output end of the delay unit 210, the output end of the inverter U1 is connected to the first input end of the NOR gate U3, the second input end of the NOR gate U3 is connected to the output end of the delay unit 210, and the output end of the NOR gate U3 is connected to the first input end of the superposition module 300.

[0036] The delay signal waveform is inverted by the inverter U1, so that the part of the inverted delay signal before the shutdown moment becomes a low level, and the part of the external control signal after the shutdown moment is also a low level. Since the NOR gate U3 outputs a high level when the inputs are all low levels, the external signal and the inverted delay signal are input to the NOR gate U3. The NOR gate U3 outputs a high level between the shutdown moment of the external control signal and the shutdown moment of the inverted delay signal to form a trigger signal.

[0037] The signal width of the trigger signal is determined by the interval between the external control signal and the off-time of the delay signal, and the off-time of the delay signal is determined by the delay value of the RC delay circuit. Therefore, by adjusting the delay value of the RC delay circuit, the signal width of the trigger signal can be adjusted. The longer the delay time of the RC delay circuit, the larger the width of the trigger signal.

[0038] The comparison operation unit 220 may also be implemented by including logic gate devices such as an inverter and a NAND gate to generate a trigger signal.

[0039] Reference Figure 1 and Figure 2 In some embodiments of the present invention, the superposition module 300 includes a switch tube U5, a resistor R6, a resistor R7, and a resistor R8; one end of the resistor R6 is connected to the output end of the delay unit 210, and the other end of the resistor R6 is respectively connected to one end of the resistor R8 and the control end of the power switch tube 100; one end of the resistor R7 is connected to the output end of the NOR gate U3, and the other end of the resistor R7 is connected to the control end of the switch tube U5; the input end of the switch tube U5 is connected to the other end of the resistor R8, and the output end of the switch tube U5 is grounded.

[0040] After being processed by delay unit 210, the external control signal forms a delayed signal, which is transmitted to the control terminal of power switch 100. The delayed signal controls the on / off period and duty cycle of power switch 100 identical to the external control signal. Therefore, the delayed signal is only delayed in time, and its control effect on power switch 100 is the same as that of the external control signal. While the delayed signal controls the on / off of power switch 100, before the delayed signal controls the complete shutdown of power switch 100, the trigger signal turns on control switch U5, lowering the voltage between resistors R6 and R8. This lowers the amplitude of the delayed signal, thereby reducing the conduction level of power switch 100 and achieving a graded shutdown effect. This reduces the peak voltage when power switch 100 is completely shut down. In this manner, the delayed signal and trigger signal are superimposed to generate a graded shutdown signal, resulting in a simple structure and easy implementation.

[0041] By adjusting the resistance value of resistor R8, the voltage drop across resistor R8 can be controlled, thereby adjusting the relative magnitude of the voltage amplitude of the graded shutdown signal in the pre-shutdown portion and the voltage amplitude of other portions. The voltage amplitude of the pre-shutdown portion controls the conduction degree of the power switch tube 100. That is, by adjusting resistor R8, the conduction degree of the power switch tube 100 during the pre-shutdown process can be adjusted. In this way, a reasonable resistance value of resistor R8 can be set according to actual application requirements to control the conduction degree of the power switch tube 100 during the pre-shutdown process.

[0042] In some embodiments, one end of resistor R6 can be directly connected to an external control signal. In this case, the external control signal is superimposed on the trigger signal without any delay. Since the external control signal turns off at the same time as the trigger signal suddenly changes to a high level, switch U5 needs to be switched to a pull-up mode. Specifically, the input end of switch U5 is connected to the power supply, and the output end of switch U5 is connected to the other end of resistor R6 and one end of resistor R8, respectively. The other end of resistor R8 is grounded. In this way, when the trigger signal turns on switch U5, the voltage between resistors R6 and R8 is pulled high, thereby superimposing the external control signal and the trigger signal to form a graded shutdown signal.

[0043] Reference Figure 1 and Figure 2 In some embodiments of the present invention, an inverter U2 is further included, wherein the input end of the inverter U2 is connected to the output end of the inverter U1, and the output end of the inverter U2 is connected to one end of the resistor R6. Both the inverter U1 and the inverter U2 are Schmitt inverters.

[0044] In comparison operation unit 220, inverter U1 is a Schmitt inverter, which facilitates trimming the input delayed signal, preventing waveform changes of the delayed signal due to interference and other factors, and improving circuit reliability. Furthermore, the delayed signal needs to be transmitted to the control terminal of power switch tube 100. Inverter U2 obtains the inverted delayed signal from the output terminal of inverter U1 and then restores the delayed signal. Since inverter U2 is also a Schmitt inverter, it can trim the waveform of the delayed signal, ensuring that the delayed signal maintains its waveform unchanged when transmitted through inverters U1 and U2 to the control terminal of power switch tube 100, thereby improving anti-interference capabilities and reliability.

[0045] Reference Figure 1 and Figure 2 In some embodiments of the present invention, an adjustment module 400 is further included, the input end of the adjustment module 400 is connected to the output end of the superposition module 300 to adjust the amplitude of the graded shutdown signal, and the output end of the adjustment module 400 is connected to the control end of the power switch tube 100.

[0046] Since the delayed signal and the trigger signal are superimposed to form a graded shutdown signal, there may be a problem that the voltage amplitude of the graded shutdown signal is not compatible with the driving voltage range of the power switch tube 100. Therefore, by providing an adjustment module 400 to adjust the graded shutdown signal, so that the signal amplitude of the graded shutdown signal meets the requirement of driving the power switch tube 100, it is beneficial to make the operation of the power switch tube 100 more stable and improve the reliability.

[0047] Reference Figure 1 and Figure 2In some embodiments of the present invention, the regulation module 400 includes a switch tube U4, a resistor R9, and a resistor R10. The control end of the switch tube U4 is connected to the output end of the superposition module 300, the input end of the switch tube U4 is connected to the power supply end, the output end of the switch tube U4 is connected to one end of the resistor R9, the other end of the resistor R9 is respectively connected to one end of the resistor R10 and the control end of the power switch tube 100, and the other end of the resistor R10 is grounded.

[0048] The graded shutdown signal is transmitted to the control end of the switch tube U4 to control the on and off of the switch tube U4. The current generated by the on and off of the switch tube U4 flows through the resistor R9 and the resistor R10, forming a signal with appropriate amplitude between the resistor R9 and the resistor R10. This signal is consistent with the waveform of the graded shutdown signal, thereby achieving the effect of adjusting the voltage amplitude of the graded shutdown signal.

[0049] The switch tube U4 and the switch tube U5 can be common devices such as triodes or field effect tubes.

[0050] refer to Figure 2 and Figure 3 , use the waveform detector to detect the above-mentioned hierarchical shutdown circuit, Figure 3 In the figure, channel 1 is the external control signal waveform; channel 2 is the delayed signal waveform at the output of delay unit 210; channel 3 is the trigger signal waveform at the output of the comparison processing unit; and channel 4 is the graded shutdown signal waveform after the trigger signal and the delayed signal are superimposed. It can be clearly seen from the figure that the waveforms and signal widths of the external control signal and the delayed signal are consistent, and the effect achieved by using the delayed signal as the basis for controlling the power switch tube 100 is the same as that achieved by the external control signal. The turn-off time of the trigger signal and the delayed signal are consistent, so that superposition does not affect the turn-off time of the power switch tube 100.

[0051] refer to Figure 3 and Figure 4 , Figure 4 This is the signal waveform after adjusting the resistance of resistor R8. Figure 3 and Figure 4 It can be clearly seen that adjusting the resistance of resistor R8 can change the signal amplitude of the graded shutdown signal at the pre-shutdown part, thereby controlling the conduction degree of the power switch tube 100 during pre-shutdown. Therefore, the resistance of resistor R8 is adjusted according to the actual application situation to meet actual usage requirements.

[0052] refer to Figure 5 , Figure 5The following are actual test signal waveforms. Specifically, power switch tube 100 is an IGBT, with two IGBTs forming a half-bridge structure, such as the bridge arms in a common inverter circuit. The test simulates the extreme situation of a direct-through short circuit between the upper and lower IGBTs. Channel 1 is the control-terminal signal waveform of the upper IGBT, i.e., the aforementioned staged shutdown signal waveform; Channel 2 is the voltage signal waveform between the collector and emitter of the upper IGBT; Channel 3 is the current signal waveform flowing through the upper and lower IGBTs; and Channel 4 is the voltage signal waveform between the collector and emitter of the lower IGBT. The control-terminal signal waveform of the lower IGBT is identical to that of the upper IGBT and is not shown in the figure.

[0053] Depend on Figure 5 It can be clearly seen that when the upper and lower IGBTs are turned off through a graded shutdown method, during the pre-shutdown process, although a spike voltage appears in the voltage waveform between the collector and emitter of the IGBT, the amplitude is small. In addition, during the pre-shutdown process, due to the reduced conduction level of the IGBT, the voltage between the collector and emitter of the IGBT drops. When the IGBT is completely shut down, although a large spike voltage appears, the maximum value of the spike voltage does not exceed the maximum voltage value when the IGBT is on. Therefore, the spike voltage generated during complete shutdown will not damage the device. The current flowing through the IGBT also decreases as the IGBT pre-shutdown process progresses, and the final current signal waveform reaches its minimum value when the IGBT is completely shut down. This process intuitively demonstrates that controlling the shutdown of the power switch tube 100 through a graded shutdown method can effectively reduce the spike voltage, achieve the effect of protecting the components in the circuit, and improve the reliability of the circuit.

[0054] A hierarchical shutdown circuit of the present invention uses the hardware's own functions to achieve hierarchical shutdown effects without using programmable components, and has a simple structure and is easy to use.

[0055] According to an embodiment of the second aspect of the present invention, an electrical device includes a power switch tube 100, a control module and a hierarchical shutdown circuit in the above embodiment, the output end of the control module is respectively connected to the input end of the trigger signal generating module 200 and the input end of the superposition module 300, the output end of the superposition module 300 is connected to the control end of the power switch tube 100, the input end of the power switch tube 100 is connected to the power supply end, and the output end of the power switch tube 100 is connected to the external load.

[0056] The control module generates a control signal and transmits it to the power switch 100 via a graded shutdown circuit to control the on and off cycles of the power switch 100, thereby regulating the output power to meet the load's operating requirements. Furthermore, the trigger module generates a trigger signal, which the superposition module superimposes with the control signal to form a graded shutdown signal, which is then transmitted to the power switch 100 to implement graded shutdown control. This effectively suppresses voltage spikes, preventing damage to circuit components caused by these spikes and improving reliability.

[0057] Reference Figure 1 and Figure 2 In some embodiments of the present invention, the power switch tube 100 is an IGBT, the collector of the IGBT is connected to the power supply end, the emitter of the IGBT is connected to the external load, and the gate of the IGBT is connected to the output end of the superposition module 300.

[0058] The power switch tube 100 uses an IGBT, which has the advantages of high input impedance, low conduction voltage drop, and fast response speed. The use of an IGBT is beneficial to improving the overall performance of electrical equipment.

[0059] Of course, the invention is not limited to the above-mentioned embodiments. Those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A hierarchical shutdown circuit, characterized in that: include: A trigger signal generating module (200), wherein an input end of the trigger signal generating module (200) is connected to an external control signal to generate a trigger signal according to the external control signal; A superposition module (300), wherein a first input end of the superposition module (300) is connected to an output end of the trigger signal generating module (200), a second input end of the superposition module (300) is connected to an external control signal, the superposition module (300) processes the external control signal according to the trigger signal to form a graded shutdown signal, and the output end of the superposition module (300) is connected to a control end of an external power switch tube (100); the trigger signal generating module (200) comprises a delay unit (210) and a comparison operation unit (220), an input end of the delay unit (210) is connected to an external control signal, a first input end of the comparison operation unit (220) is connected to an output end of the delay unit (210), a second input end of the comparison operation unit (220) is connected to an external control signal, and an output end of the comparison operation unit (220) is connected to the first input end of the superposition module (300); The comparison operation unit (220) includes an inverter U1 and a NOR gate U3, the input end of the inverter U1 is connected to the output end of the delay unit (210), the output end of the inverter U1 is connected to the first input end of the NOR gate U3, the second input end of the NOR gate U3 is connected to the output end of the delay unit (210), and the output end of the NOR gate U3 is connected to the first input end of the superposition module (300); the superposition module (300) includes a switch tube U5, a resistor R6, a resistor R7, and a resistor R8; One end of the resistor R6 is connected to the output end of the delay unit (210), and the other end of the resistor R6 is respectively connected to one end of the resistor R8 and the control end of the external power switch tube (100); One end of the resistor R7 is connected to the output end of the NOR gate U3, and the other end of the resistor R7 is connected to the control end of the switch tube U5; The input end of the switch tube U5 is connected to the other end of the resistor R8, and the output end of the switch tube U5 is grounded; It also includes an inverter U2, the input end of the inverter U2 is connected to the output end of the inverter U1, and the output end of the inverter U2 is connected to one end of the resistor R6. The inverter U1 and the inverter U2 are both Schmitt inverters, wherein the inverter U1 inverts the waveform of the delay signal, the inverter U2 obtains the inverted delay signal from the output end of the inverter U1, and then restores the delay signal to trim the waveform of the delay signal, keeping the waveform of the delay signal unchanged.

2. A hierarchical shutdown circuit according to claim 1, characterized in that: The delay unit (210) comprises a resistor R1 and a capacitor C1, one end of the resistor R1 is connected to an external control signal, the other end of the resistor R1 is respectively connected to one end of the capacitor C1 and the first input end of the comparison operation unit (220), and the other end of the capacitor C1 is grounded.

3. The hierarchical shutdown circuit according to claim 1, characterized in that: It also includes a regulating module (400), the input end of the regulating module (400) is connected to the output end of the superposition module (300) to regulate the amplitude of the graded shutdown signal, and the output end of the regulating module (400) is connected to the control end of the external power switch tube (100).

4. A hierarchical shutdown circuit according to claim 3, characterized in that: The regulating module (400) comprises a switch tube U4, a resistor R9, and a resistor R10; the control end of the switch tube U4 is connected to the output end of the superposition module (300); the input end of the switch tube U4 is connected to the power supply end; the output end of the switch tube U4 is connected to one end of the resistor R9; the other end of the resistor R9 is respectively connected to one end of the resistor R10 and the control end of the external power switch tube (100); and the other end of the resistor R10 is grounded.

5. Electrical equipment, characterized in that: The invention comprises a power switch tube (100), a control module, and a hierarchical shutdown circuit according to any one of claims 1 to 4, wherein the output end of the control module is respectively connected to the trigger signal generating module (200) and the input end of the superposition module (300), the output end of the superposition module (300) is connected to the control end of the power switch tube (100), the input end of the power switch tube (100) is connected to the power supply end, and the output end of the power switch tube (100) is connected to an external load.

6. The electrical device according to claim 5, characterized in that: The power switch tube (100) is an IGBT, the collector of the IGBT is connected to the power supply end, the emitter of the IGBT is connected to the external load, and the gate of the IGBT is connected to the output end of the superposition module (300).

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