Power tube short-circuit protection circuit and control method thereof

Abstract

The invention discloses a power tube short-circuit protection circuit and a control method thereof, and relates to the technical field of power device protection, and the power tube short-circuit protection circuit comprises a current detection module which is connected with a power tube driving circuit; the hardware wave sealing module is respectively connected with the current detection module and the power tube driving circuit; wherein the current detection module samples current flowing through a power tube in the power tube driving circuit in real time and outputs a current detection signal, and the hardware wave sealing module compares the current detection signal with a reference signal; and entering a normal working state changing along with the received pulse signal or a protection state triggering wave sealing of the received pulse signal according to a comparison result, and outputting a corresponding driving control signal to a power tube. According to the invention, low-delay current sampling and quick-response hardware wave sealing are realized, and the effect of providing short-circuit protection for the power tube in time is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of power device protection, and in particular to a power tube short-circuit protection circuit and a control method thereof. Background Art

[0002] During the actual opening process of the power tube, a load short circuit may occur. At this time, the power tube directly bears the bus voltage of the main power circuit, forming a direct pass. In the related technology, many high-voltage control devices adopt the short-circuit protection control method, which has the problem of large current sampling delay. Usually, the delay is reduced by improving the processing power of the MCU, but the processing power of the MCU is directly related to the cost. Therefore, if the current sampling delay is designed to be too long or the processing power of the MCU is insufficient, it will not be able to meet the requirements of the sealing time, and it will not be able to truly protect the power tube. In addition, when the resources and power supply of the MCU are abnormal, the wave cannot be sealed in time, and the power tube cannot be protected. Summary of the invention

[0003] The main purpose of the present application is to provide a power tube short-circuit protection circuit and a control method thereof, aiming to solve the technical problem in the related art that the power tube cannot be protected in time when the load is short-circuited.

[0004] To achieve the above purpose, the present application proposes a power tube short-circuit protection circuit, which is connected to a power tube driving circuit. The power tube short-circuit protection circuit includes:

[0005] A current detection module is connected to the power tube drive circuit. The current detection module is used to sample the current flowing through the power tube in the power tube drive circuit in real time and output a current detection signal.

[0006] The hardware wave-sealing module is connected to the current detection module and the power tube driving circuit respectively. The hardware wave-sealing module is used to compare the current detection signal with the reference signal, and enter a normal working state that follows the changes of the received pulse signal or trigger a protection state for sealing the received pulse signal according to the comparison result, and output a corresponding drive control signal to the power tube.

[0007] In one embodiment, the power tube short circuit protection circuit further includes:

[0008] The control module is connected to the current detection module and the hardware wave-sealing module respectively, and is used to output a pulse signal to the hardware wave-sealing module, and when an overcurrent fault is identified according to the current detection signal, the pulse signal is sealed and the sealed pulse signal is output;

[0009] The hardware wave-sealing module is also used to enter a secondary protection state following the change of the received pulse signal after the wave-sealing according to the comparison result, and output a corresponding drive control signal to the power tube.

[0010] In one embodiment, the current detection module includes:

[0011] A high-voltage side processing unit is connected to the current detection module. The high-voltage side processing unit is used to sample the current flowing through the power tube in the power tube driving circuit in real time, generate a sampling signal, and output the sampling signal after filtering;

[0012] An isolation sampling unit is connected to the high-voltage side processing unit, and is used to provide electrical isolation and output the received sampling signal;

[0013] The low-voltage side processing unit is connected to the isolation sampling unit and the hardware wave-sealing module respectively. The low-voltage side processing unit is used to amplify and filter the received sampling signal and output a current detection signal.

[0014] In one embodiment, the high-voltage side processing unit includes a current sampling subunit, a first filtering subunit, a second filtering subunit, an absorption capacitor subunit, a third filtering subunit and a first decoupling subunit;

[0015] One end of the current sampling subunit is respectively connected to the power tube driving circuit and the input end of the first filtering subunit, the power tube driving circuit is connected to the positive DC bus, the other end of the current sampling subunit is respectively connected to the negative DC bus and the input end of the second filtering subunit, the output end of the first filtering subunit is respectively connected to one end of the absorption capacitor subunit and the first input end of the isolation sampling unit, the output end of the second filtering subunit is respectively connected to the other end of the absorption capacitor subunit and the second input end of the isolation sampling unit, one end of the third filtering subunit is respectively connected to the positive pole of the power supply, one end of the first decoupling subunit and the first power supply end of the isolation sampling unit, the ground end of the first filtering subunit, the ground end of the second filtering subunit, the other end of the third filtering subunit, the other end of the first decoupling subunit and the first ground end of the isolation sampling unit are all connected to the negative DC bus.

[0016] In one embodiment, the current sampling subunit includes a resistor R1 and a resistor R2, the first filtering subunit includes a resistor R3 and a capacitor C2, the second filtering subunit includes a resistor R4 and a capacitor C3, the absorption capacitor subunit includes a capacitor C1, the third filtering subunit includes a capacitor C4, and the first decoupling subunit includes a capacitor C5;

[0017] One end of the resistor R1 is respectively connected to the power tube driving circuit, one end of the resistor R2 and one end of the resistor R3, the other end of the resistor R1 is respectively connected to the negative DC bus, the other end of the resistor R2 and one end of the resistor R4, the other end of the resistor R3 is respectively connected to one end of the capacitor C1, one end of the capacitor C2 and the first input end of the isolation sampling unit, the other end of the resistor R4 is respectively connected to the other end of the capacitor C1, one end of the capacitor C3 and the second input end of the isolation sampling unit, one end of the capacitor C4 is respectively connected to the positive electrode of the power supply, one end of the capacitor C5 and the first power supply end of the isolation sampling unit, and the other end of the capacitor C2, the other end of the capacitor C3, the other end of the capacitor C4 and the other end of the capacitor C5 are all connected to the negative DC bus.

[0018] In one embodiment, the low-voltage side processing unit includes a signal amplification subunit, a fourth filtering subunit, a second decoupling subunit, a voltage divider network subunit, a first voltage stabilization subunit, a feedback network subunit, and a first RC filtering subunit;

[0019] The positive input end of the voltage-dividing network subunit is connected to the first output end of the isolation sampling unit, the positive output end of the voltage-dividing network subunit is respectively connected to the first input end of the signal amplifying subunit and one end of the first voltage stabilizing subunit, the other end of the first voltage stabilizing subunit is connected to the low-voltage power supply, the negative input end of the voltage-dividing network subunit is connected to the second output end of the isolation sampling unit, the negative output end of the voltage-dividing network subunit is respectively connected to the second input end of the signal amplifying subunit and one end of the feedback network subunit, the other end of the feedback network subunit is respectively connected to the output end of the signal amplifying subunit and one end of the first RC filtering subunit, the other end of the first RC filtering subunit is connected to the hardware wave-sealing module, one end of the fourth filtering subunit is respectively connected to the second power supply end of the isolation sampling unit, the negative pole of the power supply and one end of the second decoupling subunit, the second grounding end of the isolation sampling unit, the other end of the fourth filtering subunit and the other end of the second decoupling subunit are all grounded.

[0020] In one embodiment, the signal amplification subunit includes an amplifier U2, the fourth filtering subunit includes a capacitor C6, the second decoupling subunit includes a capacitor C7, the voltage divider network subunit includes a resistor R5 and a resistor R6, the first voltage stabilization subunit includes a resistor R7 and a capacitor C8, the feedback network subunit includes a resistor R8 and a capacitor C9, and the first RC filtering subunit includes a resistor R9 and a capacitor C10;

[0021] One end of the resistor R5 is connected to the first output end of the isolation sampling unit, the other end of the resistor R5 is respectively connected to one end of the resistor R7, one end of the capacitor C8 and the first input end of the amplifier U2, one end of the resistor R6 is respectively connected to the second output end of the isolation sampling unit, the other end of the resistor R6 is respectively connected to the second input end of the amplifier U2, one end of the capacitor C9 and one end of the resistor R8, the other end of the resistor R7 is respectively connected to the other end of the capacitor C8 and the low-voltage power supply, the other end of the capacitor C9 is respectively connected to the other end of the resistor R8, the output end of the amplifier U2 and one end of the resistor R9, the other end of the resistor R9 is respectively connected to one end of the capacitor C10 and the hardware wave sealing module, one end of the capacitor C6 is respectively connected to the second power supply end of the isolation sampling unit, the negative electrode of the power supply and one end of the capacitor C7, and the other end of the capacitor C6, the other end of the capacitor C7 and the other end of the capacitor C10 are all grounded.

[0022] In one embodiment, the hardware wave-encapsulation module includes:

[0023] A comparison unit connected to the current detection module, the comparison unit is used to compare the current value corresponding to the current detection signal with the preset current threshold corresponding to the reference signal, and output a comparison signal;

[0024] The logic unit is connected to the comparison unit and the control module. The logic unit is used to perform logic and processing according to the comparison signal and the pulse signal to output a driving control signal to the power tube in a normal working state or a protection state.

[0025] In one embodiment, the comparison unit includes a current comparison subunit, a second RC filter subunit, a voltage-dividing resistor subunit, a second voltage-stabilizing subunit, a third RC filter subunit, and a third voltage-stabilizing subunit;

[0026] The first input end of the current comparison subunit is connected to the current detection module through the second RC filter subunit, the second input end of the current comparison subunit is respectively connected to one end of the voltage-dividing resistor subunit and one end of the second voltage-stabilizing subunit, the other end of the second voltage-stabilizing subunit is connected to the positive pole of the power supply, the output end of the current comparison subunit is respectively connected to one end of the third voltage-stabilizing subunit and the logic unit through the third RC filter subunit, the other end of the third voltage-stabilizing subunit is connected to the positive pole of the power supply, and the other end of the voltage-dividing resistor subunit is grounded.

[0027] In one embodiment, the current comparison subunit includes a comparator U3, the second RC filter subunit includes a resistor R10 and a capacitor C11, the voltage dividing resistor subunit includes a resistor R12, the second voltage stabilizing subunit includes a resistor R11 and a capacitor C12, the third RC filter subunit includes a resistor R13 and a capacitor C13, and the third voltage stabilizing subunit includes a resistor R14 and a capacitor C14;

[0028] A first input end of the comparator U3 is respectively connected to one end of the resistor R10 and one end of the capacitor C11, the other end of the resistor R10 is connected to the current detection module, a second input end of the comparator U3 is respectively connected to one end of the resistor R12, one end of the resistor R11 and one end of the capacitor C12, the other end of the resistor R11 is respectively connected to the positive electrode of the power supply and the other end of the capacitor C12, the output end of the comparator U3 is respectively connected to one end of the capacitor C13, one end of the resistor R14, one end of the capacitor C14 and the logic unit through the resistor R13, the other end of the resistor R14 is respectively connected to the positive electrode of the power supply and the other end of the capacitor C14, the other end of the resistor R12, the other end of the capacitor C11 and the other end of the capacitor C13 are all grounded.

[0029] In one embodiment, the logic unit includes a logic AND subunit, a fourth RC filter subunit, a fifth RC filter subunit, and a fifth filter subunit;

[0030] The first input end of the logic AND subunit is connected to the comparison unit through the fourth RC filter subunit, the second input end of the logic AND subunit is connected to the control module through the fifth RC filter subunit, the output end of the logic AND subunit is connected to the power tube, the power end of the logic AND subunit is respectively connected to the positive pole of the power supply and one end of the fifth filter subunit, and the ground end of the logic AND subunit and the other end of the fifth filter subunit are both grounded.

[0031] In one embodiment, the logic and sub-unit includes a logic and U4, the fourth RC filter sub-unit includes a resistor R15 and a capacitor C15, the fifth RC filter sub-unit includes a resistor R16 and a capacitor C16, and the fifth filter sub-unit includes a capacitor C17;

[0032] The first input end of the logic AND U4 is respectively connected to one end of the resistor R15 and one end of the capacitor C15, the other end of the resistor R15 is connected to the comparison unit, the second input end of the logic AND U4 is respectively connected to one end of the resistor R16 and one end of the capacitor C16, the other end of the resistor R16 is connected to the control module, the output end of the logic AND U4 is connected to the power tube, the power supply end of the logic AND U4 is respectively connected to the positive pole of the power supply and one end of the capacitor C17, and the ground end of the logic AND U4, the other end of the capacitor C15, the other end of the capacitor C16 and the other end of the capacitor C17 are all grounded.

[0033] In addition, to achieve the above purpose, the present application also proposes a control method for a power tube short-circuit protection circuit, the power tube short-circuit protection circuit is the power tube short-circuit protection circuit as described above, and the control method includes:

[0034] When the power tube driving circuit is working, the current flowing through the power tube in the power tube driving circuit is sampled in real time through the current detection module, and a current detection signal is output;

[0035] The current detection signal is compared with the reference signal through the hardware wave-sealing module to determine whether there is overcurrent in the power tube according to the comparison result;

[0036] If there is no overcurrent, the hardware wave-sealing module enters a normal working state following the changes of the received pulse signal, and outputs a corresponding drive control signal to the power tube to enable the power tube to work normally;

[0037] If there is an overcurrent, the hardware wave-sealing module triggers the protection state of the received pulse signal wave-sealing, and outputs the corresponding drive control signal to the power tube to provide short-circuit protection for the power tube.

[0038] In one embodiment, the power tube short circuit protection circuit further includes a control module, and after the step of sampling the current flowing through the power tube in the power tube driving circuit in real time through the current detection module and outputting the current detection signal, the control method further includes:

[0039] When an overcurrent fault is identified according to the current detection signal, the control module blocks the pulse signal and outputs the blocked pulse signal, so that the hardware blocking module follows the changes of the received blocked pulse signal and outputs the blocked drive control signal to the power tube.

[0040] In one embodiment, after the step of triggering the protection state of the received pulse signal encapsulation by the hardware encapsulation module and outputting the corresponding drive control signal to the power tube to provide short-circuit protection for the power tube, the control method further includes:

[0041] Return to the step of sampling the current flowing through the power tube in the power tube driving circuit in real time through the current detection module and outputting a current detection signal to continue to determine whether there is an overcurrent in the power tube;

[0042] If there is no overcurrent, the hardware wave-sealing module enters the normal working state, follows the changes of the received pulse signal after the wave is sealed, and outputs the drive control signal after the wave is sealed to the power tube to provide secondary short-circuit protection for the power tube.

[0043] One or more technical solutions proposed in this application have at least the following technical effects:

[0044] A power tube short-circuit protection circuit is proposed. The current flowing through the power tube in the power tube driving circuit is sampled in real time by a current detection module, and a current detection signal is output, so as to realize low-latency current sampling. Then, the current detection signal is compared with the reference signal by a hardware wave-sealing module. If there is no overcurrent in the power tube, the hardware wave-sealing module enters a normal working state following the change of the received pulse signal, and outputs a corresponding drive control signal to the power tube, so that the power tube can work normally. If there is an overcurrent in the power tube, the hardware wave-sealing module triggers the protection state of the wave-sealing of the received pulse signal, and outputs a corresponding drive control signal to the power tube, so as to provide short-circuit protection for the power tube. Different actions can be performed according to different situations, which will not affect the normal operation of the power tube, and can respond quickly in the first time when the power tube is short-circuited, perform hardware wave-sealing in time, shut down the power tube, and provide timely short-circuit protection for the power tube. In addition, the circuit structure is simple, can be realized by only a few types of components, and has the effect of low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0047] Figure 1 This is a connection diagram of an embodiment of a power tube short-circuit protection circuit of the present application;

[0048] Figure 2 A circuit schematic diagram of a current detection module in the power tube short-circuit protection circuit of the present application;

[0049] Figure 3 for Figure 2 Circuit schematic diagram of the medium and high voltage side processing unit;

[0050] Figure 4 for Figure 2 Circuit schematic diagram of the medium and low voltage side processing unit;

[0051] Figure 5 A circuit schematic diagram of a hardware wave-sealing module in the power tube short-circuit protection circuit of the present application;

[0052] Figure 6 for Figure 5 The circuit schematic diagram of the comparison unit in FIG.

[0053] Figure 7 for Figure 5 The circuit schematic diagram of the logic unit in the figure;

[0054] Figure 8 This is a flow chart of a control method for a power tube short-circuit protection circuit of the present application.

[0055] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0057] It should be noted that if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0058] With the development of photovoltaic inverters, industrial frequency converters, and electric vehicle controllers, semiconductor devices such as IGBT (Insulated Gate Bipolar Transistor) and MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) are widely used as main power change devices. During the actual opening process of the power tube, a load short circuit may occur. At this time, the power tube directly bears the bus voltage of the main power circuit, forming a direct pass, and a very large short-circuit current flows instantly, which can easily cause damage to the power tube.

[0059] In the related art, many high-voltage control devices use MCU (Microcontroller Unit) to implement short-circuit protection control. Specifically, the current flowing through the power tube is collected in real time through the current sampling circuit. When the current exceeds the set protection threshold, the MCU cuts off the power tube drive control signal to achieve wave blocking. In this method, there are strict requirements for the delay time of current sampling and the wave blocking time of MCU. It is required that the total delay of these two parts cannot exceed the short-circuit tolerance time of the power tube, which is generally at the microsecond (us) level. At present, most current sampling circuits are implemented using current sensors. The delay of this sampling method is large; moreover, the processing power of the MCU is directly related to the cost of the MCU. The MCU with high processing power also has high cost. Therefore, if the current sampling delay is designed to be too long or the processing power of the MCU is insufficient, the wave blocking time requirement cannot be met, and the power tube cannot be truly protected. In addition, when the resources and power supply of the MCU are abnormal, the wave cannot be blocked in time, and the power tube cannot be protected.

[0060] In view of the above problems, the present application provides a power tube short circuit protection circuit and a control method thereof. The present application and the following embodiments are described below in conjunction with the accompanying drawings.

[0061] The present application provides a power tube short-circuit protection circuit.

[0062] In one embodiment of the present application, refer to Figure 1 , Figure 1 It is a connection diagram of an embodiment of a power tube short-circuit protection circuit. The power tube short-circuit protection circuit 1 is connected to a power tube driving circuit 2 .

[0063] In this embodiment, the power tube short-circuit protection circuit 1 includes a current detection module 10 and a hardware wave-sealing module 20 .

[0064] The current detection module 10 is connected to the power tube driving circuit 2, and is used to sample the current flowing through the power tube in the power tube driving circuit 2 in real time and output a current detection signal;

[0065] The hardware wave-sealing module 20 is connected to the current detection module 10 and the power tube driving circuit 2 respectively. The hardware wave-sealing module 20 is used to compare the current detection signal with the reference signal, and enter a normal working state that follows the changes of the received pulse signal or trigger a protection state for sealing the received pulse signal according to the comparison result, and output a corresponding drive control signal to the power tube.

[0066] It should be noted that the power tube driving circuit 2 is a driving circuit that uses power tubes to realize functions such as switching, rectification, and inversion. The number of power tubes used therein is not limited. Multiple power tubes can specifically constitute a half-bridge, full-bridge, three-phase full-bridge and other structural circuits to realize various functions. The specific selection can be based on actual needs and is not limited here. It can be understood that in this embodiment, the power tube can be a MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor: Metal Oxide Semiconductor Field-Effect Transistor), a JFET tube (Junction Field-Effect Transistor: Junction Field Effect Transistor), an IGBT tube or a power semiconductor switch (such as gallium nitride power semiconductor, silicon carbide power device, etc.) and other power switching devices, which can be selected according to actual needs and are not limited here.

[0067] For example, Figure 1 As shown, one end of the power tube driving circuit 2 is connected to the positive DC bus Vbus+, and the other end is connected to the negative DC bus Vbus- through the current detection module 10. The control end of each power tube therein is connected to the output of the hardware wave sealing module 20 to receive the driving control signal PWM_S.

[0068] It should also be noted that the current detection module 10 can be a detection circuit composed of simple components, such as Figure 1 As shown, it can be connected between the power tube of the power tube driving circuit 2 and the negative DC bus Vbus-. When the power tube driving circuit 2 is working, the current flowing through the power tube in the power tube driving circuit 2 is sampled in real time, and a current detection signal I_S is output. Compared with the sampling method of the current sensor, when the current detection module 10 detects the current of the power tube, a current detection signal can be obtained more quickly, and low-latency current sampling is realized, and the cost is lower.

[0069] In addition, it should be noted that the hardware encapsulation module can be a logic control circuit composed of simple components and logic devices, such as Figure 1As shown, its input end is connected to the current detection module 10, and its output end is connected to the power tube of the power tube driving circuit 2, and the driving control signal PWM_S is sent to the corresponding power tube. At the same time, it also receives the pulse signal PWM input from the outside or the previous control module. The hardware packaging module can compare the current detection signal I_S with the reference signal to determine whether there is overcurrent in the power tube according to the comparison result; if there is no overcurrent, it enters the normal working state following the change of the received pulse signal PWM, and outputs the corresponding driving control signal PWM_S to the power tube to make the power tube work normally; if there is overcurrent, it triggers the protection state of the received pulse signal PWM wave envelope, and outputs the corresponding driving control signal PWM_S to the power tube to provide short-circuit protection for the power tube.

[0070] The working process of this embodiment is:

[0071] When there is no load short circuit in the power tube driving circuit 2 and the power tube works normally, the current detection module 10 samples the current of the power tube and then outputs the current detection signal I_S to the hardware wave-sealing module 20. The hardware wave-sealing module 20 compares the current detection signal I_S with the reference signal. The current value corresponding to the current detection signal I_S is within the preset current threshold corresponding to the reference signal. At this time, the hardware wave-sealing module 20 enters a normal working state following the change of the received pulse signal. If the received pulse signal PWM is at a high level, a high-level drive control signal PWM_S is output to the power tube. If the received pulse signal PWM is at a low level, a low-level drive control signal PWM_S is output to the power tube, so that the power tube is normally turned on or off according to the drive control signal.

[0072] When there is a load short circuit in the power tube driving circuit 2 and the current on the power tube is overcurrent, the current detection module 10 samples the current of the power tube and outputs a current detection signal I_S to the hardware wave-sealing module 20. The hardware wave-sealing module 20 compares the current detection signal I_S with the reference signal. The current value corresponding to the current detection signal I_S exceeds the preset current threshold corresponding to the reference signal. At this time, the hardware wave-sealing module 20 triggers the protection state of the received pulse signal wave-sealing. Regardless of whether the received pulse signal PWM is high or low, a low-level drive control signal PWM_S will be output to the power tube accordingly, so that the power tube is turned off according to the drive control signal to avoid damage to it due to overcurrent.

[0073] The power tube short-circuit protection circuit provided in this embodiment samples the current flowing through the power tube in the power tube driving circuit in real time through the current detection module, outputs the current detection signal, and realizes low-latency current sampling; then the current detection signal is compared with the reference signal through the hardware wave-sealing module. If there is no overcurrent in the power tube, the hardware wave-sealing module enters a normal working state following the changes of the received pulse signal, and outputs a corresponding drive control signal to the power tube to make the power tube work normally. If there is an overcurrent in the power tube, the hardware wave-sealing module triggers the protection state of the wave-sealing of the received pulse signal, outputs the corresponding drive control signal to the power tube, and provides short-circuit protection for the power tube. Different actions can be performed for different situations, which will not affect the normal operation of the power tube, and can respond quickly in the first time when the power tube is short-circuited, perform hardware wave-sealing in time, turn off the power tube, and provide timely short-circuit protection for the power tube. In addition, the circuit structure is simple, can be realized by only a few types of components, and has the effect of low cost.

[0074] In a feasible implementation manner, the power tube short-circuit protection circuit 1 may further include a control module.

[0075] The control module is respectively connected to the current detection module 10 and the hardware wave-sealing module 20, and is used to output a pulse signal to the hardware wave-sealing module 20, and when an overcurrent fault is identified according to the current detection signal, the pulse signal is wave-sealed and the pulse signal after wave-sealing is output;

[0076] The hardware wave-encapsulation module 20 is also used to enter a secondary protection state following the change of the received pulse signal after the wave-encapsulation according to the comparison result, and output a corresponding driving control signal to the power tube.

[0077] It should be noted that the control module can be a device for controlling the power tube in the power tube driving circuit 2, such as a programmable controller such as an MCU. On the one hand, it can generate a corresponding pulse signal PWM according to user needs or system instructions, and control the power tube through the hardware wave-sealing module 20; on the other hand, it can receive a current detection signal, and use its own built-in program to determine whether there is an over-current fault in the power tube according to the current detection signal. If an over-current fault is identified, the pulse signal is blocked and the blocked pulse signal is output; at this time, even if the current of the power tube is temporarily reduced by the hardware wave-sealing of the hardware wave-sealing module 20, the hardware wave-sealing module 20 can still use the characteristic of following the changes of the received pulse signal to continue to output the blocked drive control signal, so that the power tube remains turned off, so as to avoid the situation where the power tube is temporarily turned off when the load is short-circuited, so that the current drops and then continues to be turned on, resulting in another short-circuit fault.

[0078] For example, Figure 1As shown, the control module can output a pulse signal PWM to the hardware wave-encapsulation module 20, so that the hardware wave-encapsulation module 20 can output a corresponding drive control signal PWM_S, and can also receive a current detection signal I_S output by the current detection module 10. In some implementations, the control module can also report the fault result to an external device for reminder when an overcurrent fault is identified.

[0079] The working process of this embodiment is:

[0080] Assume that there is a load short circuit in the power tube driving circuit 2, and the current on the power tube is overcurrent; firstly, through the cooperation of the current detection module 10 and the hardware wave-sealing module 20, the hardware wave-sealing module 20 outputs a low-level driving control signal PWM_S to the power tube, so that the power tube is turned off. For details, please refer to the above and will not be repeated here; at the same time, the control module will also identify the overcurrent fault according to the current detection signal I_S output by the current detection module 10, and the pulse signal is blocked, and the pulse signal PWM after blocking is output to the hardware wave-sealing module 20; then, after the power tube is turned off, the current on the power tube will decrease. After the current detection module 10 detects the current, the hardware wave-sealing module 20 may no longer be in the protection state, but switch to the normal working state. If the control module still maintains the previous high-level pulse signal, the output of the hardware wave-sealing module 20 may be pulled high, which will connect the power tube again, causing the load to short-circuit and damage the power tube. However, if the control module also performs fault identification and wave-sealing operations and outputs the pulse signal PWM after wave-sealing, even if the hardware wave-sealing module 20 is in a normal working state, it can follow the changes of the received pulse signal PWM after wave-sealing. At this time, the hardware wave-sealing module 20 is equivalent to entering a secondary protection state that follows the changes of the received pulse signal after wave-sealing, so as to output the corresponding drive control signal PWM_S after wave-sealing to the power tube, provide the power tube with secondary short-circuit protection, so that the power tube continues to remain turned off, thereby achieving long-term short-circuit protection for the power tube.

[0081] In this embodiment, when the hardware wave-sealing module has a short delay and can quickly perform the first wave-sealing, in view of the situation that after the first wave-sealing, the power tube is turned off to reduce the current, and then it may be pulled up again by PWM, the control module also waves the pulse signal and performs the second wave-sealing, so that the output of the hardware wave-sealing module remains at a low level, and the power tube continues to be turned off. This circuit rationally utilizes the delay difference between the hardware wave-sealing module and the control module in performing the wave-sealing operation, first uses the hardware wave-sealing module with a short delay to perform a wave-sealing, and then uses the control module with a longer delay to perform a second wave-sealing, which has double insurance, and the wave-sealing control of the hardware wave-sealing module precedes the wave-sealing control of the control module, which can truly achieve direct-through protection of the power tube, and realizes effective and reliable short-circuit protection of the power tube.

[0082] In another embodiment of the present application, refer to Figure 2 , Figure 2 1 is a circuit schematic diagram of a current detection module in a power tube short-circuit protection circuit. The current detection module 10 includes a high-voltage side processing unit 101 , an isolation sampling unit 102 and a low-voltage side processing unit 103 .

[0083] The high-voltage side processing unit 101 is connected to the current detection module 10, and is used to sample the current flowing through the power tube in the power tube driving circuit 2 in real time, generate a sampling signal, and output the sampling signal after filtering;

[0084] The isolation sampling unit 102 is connected to the high-voltage side processing unit 101, and the isolation sampling unit 102 is used to provide electrical isolation and output the received sampling signal;

[0085] The low-voltage side processing unit 103 is connected to the isolation sampling unit 102 and the hardware wave-sealing module 20 respectively. The low-voltage side processing unit 103 is used to amplify and filter the received sampling signal and output a current detection signal.

[0086] It should be noted that, through the high-voltage side processing unit 101, the isolation sampling unit 102 and the low-voltage side processing unit 103, the current signal flowing through the power tube can be detected, and the current signal is converted into a voltage signal and then output, that is, a current detection signal I_S is obtained, and then the current detection signal I_S is output to the hardware wave sealing module 20 and the control module respectively.

[0087] For example, Figure 2 As shown, the isolation sampling unit 102 can directly select the isolation sampling chip U1 to isolate the high voltage side from the low voltage side, and perform gain amplification and conversion on the received signal before output.

[0088] In one possible implementation, refer to Figure 3 , Figure 3 for Figure 2 The circuit schematic diagram of the medium and high voltage side processing unit, the high voltage side processing unit 101 may include a current sampling subunit 11, a first filtering subunit 12, a second filtering subunit 13, an absorption capacitor subunit 14, a third filtering subunit 15 and a first decoupling subunit 16;

[0089] Among them, one end of the current sampling subunit 11 is respectively connected to the input end of the power tube driving circuit 2 and the first filtering subunit 12, the power tube driving circuit 2 is connected to the positive DC bus Vbus+, the other end of the current sampling subunit 11 is respectively connected to the negative DC bus Vbus- and the input end of the second filtering subunit 13, the output end of the first filtering subunit 12 is respectively connected to one end of the absorption capacitor subunit 14 and the first input end of the isolation sampling unit 102, the output end of the second filtering subunit 13 is respectively connected to the other end of the absorption capacitor subunit 14 and the second input end of the isolation sampling unit 102, one end of the third filtering subunit 15 is respectively connected to the positive pole of the power supply, one end of the first decoupling subunit 16 and the first power supply end of the isolation sampling unit 102, and the ground end of the first filtering subunit 12, the ground end of the second filtering subunit 13, the other end of the third filtering subunit 15, the other end of the first decoupling subunit 16 and the first ground end of the isolation sampling unit 102 are all connected to the negative DC bus.

[0090] It should be noted that the current sampling subunit 11 is used to sample the current flowing through the power tube in the power tube driving circuit 2 in real time, generate and output a sampling signal; the filtering network composed of the first filtering subunit 12, the second filtering subunit 13 and the absorption capacitor subunit 14 filters the sampling signal and outputs the filtered sampling signal to the isolation sampling unit 102; the third filtering subunit 15 and the first decoupling subunit 16 are used to filter the power supply voltage provided by the power supply to the isolation sampling unit 102, and provide protection for the devices on the high-voltage side of the isolation sampling unit 102.

[0091] For example, Figure 2 and Figure 3 As shown, the current sampling subunit 11 includes a resistor R1 and a resistor R2, the first filtering subunit 12 includes a resistor R3 and a capacitor C2, the second filtering subunit 13 includes a resistor R4 and a capacitor C3, the absorption capacitor subunit 14 includes a capacitor C1, the third filtering subunit 15 includes a capacitor C4, and the first decoupling subunit 16 includes a capacitor C5;

[0092] One end of the resistor R1 is respectively connected to the power tube driving circuit 2, one end of the resistor R2 and one end of the resistor R3, the other end of the resistor R1 is respectively connected to the negative DC bus Vbus-, the other end of the resistor R2 and one end of the resistor R4, the other end of the resistor R3 is respectively connected to one end of the capacitor C1, one end of the capacitor C2 and the first input end of the isolation sampling unit 102, the other end of the resistor R4 is respectively connected to the other end of the capacitor C1, one end of the capacitor C3 and the second input end of the isolation sampling unit 102, one end of the capacitor C4 is respectively connected to the positive electrode of the power supply, one end of the capacitor C5 and the first power supply end of the isolation sampling unit 102, and the other end of the capacitor C2, the other end of the capacitor C3, the other end of the capacitor C4 and the other end of the capacitor C5 are all connected to the negative DC bus Vbus-.

[0093] It should be noted that resistors R1 and R2 are sampling resistors, resistors R3 and R4 are filter resistors, capacitor C1 is an absorption capacitor, capacitors C2, C3 and C4 are filter capacitors, and capacitor C5 is a decoupling capacitor. These devices constitute the circuit of the high-voltage side processing unit 101, and can detect the current signal of the power tube on the high-voltage side of the isolation sampling chip U1.

[0094] For example, Figure 2 and Figure 3 As shown, the other end of the resistor R3 is specifically connected to the first input terminal INP of the isolation sampling chip U1, the other end of the resistor R4 is specifically connected to the second input terminal INN of the isolation sampling chip U1, one end of the capacitor C4 is specifically connected to the first power supply terminal Vdd1 of the isolation sampling chip U1, and the first ground terminal GND1 of the isolation sampling chip U1 is connected to the negative DC bus Vbus-. The power supply can be a +5V power supply.

[0095] In one possible implementation, refer to Figure 4 , Figure 4 for Figure 2 The circuit schematic diagram of the medium and low voltage side processing unit, the low voltage side processing unit 103 may include a signal amplification subunit 21, a fourth filtering subunit 22, a second decoupling subunit 23, a voltage divider network subunit 24, a first voltage stabilization subunit 25, a feedback network subunit 26 and a first RC filtering subunit 27;

[0096] Among them, the positive input end of the voltage-dividing network subunit 24 is connected to the first output end of the isolation sampling unit 102, the positive output end of the voltage-dividing network subunit 24 is respectively connected to the first input end of the signal amplifying subunit 21 and one end of the first voltage stabilizing subunit 25, the other end of the first voltage stabilizing subunit 25 is connected to the low-voltage power supply, the negative input end of the voltage-dividing network subunit 24 is connected to the second output end of the isolation sampling unit 102, the negative output end of the voltage-dividing network subunit 24 is respectively connected to the second input end of the signal amplifying subunit 21 and one end of the feedback network subunit 26, the other end of the feedback network subunit 26 is respectively connected to the output end of the signal amplifying subunit 21 and one end of the first RC filtering subunit 27, the other end of the first RC filtering subunit 27 is connected to the hardware wave-sealing module 20, one end of the fourth filtering subunit 22 is respectively connected to the second power supply end of the isolation sampling unit 102, the negative pole of the power supply, and one end of the second decoupling subunit 23, the second grounding end of the isolation sampling unit 102, the other end of the fourth filtering subunit 22, and the other end of the second decoupling subunit 23 are all grounded.

[0097] It should be noted that the fourth filtering subunit 22 and the second decoupling subunit 23 are used to provide protection for the devices on the low-voltage side of the isolation sampling unit 102; the voltage divider network subunit 24 is used to perform voltage division processing on the sampling signal output by the isolation sampling unit 102, and output the voltage-divided signal; the signal amplification subunit 21 is used to amplify the received signal and output the amplified sampling signal; the first voltage stabilization subunit 25 is used to stabilize the voltage signal provided to the signal amplification subunit 21 by the low-voltage power supply; the feedback network subunit 26 is used to timely feedback the amplified sampling signal output by the signal amplification subunit 21 to adjust the amplification gain of the signal amplification subunit 21; the first RC filtering subunit 27 is used to filter the amplified sampling signal to output the current detection signal to the hardware sealing module 20 or the control module.

[0098] For example, Figure 2 and Figure 4 As shown, the signal amplification subunit 21 includes an amplifier U2, the fourth filtering subunit 22 includes a capacitor C6, the second decoupling subunit 23 includes a capacitor C7, the voltage divider network subunit 24 includes a resistor R5 and a resistor R6, the first voltage stabilization subunit 25 includes a resistor R7 and a capacitor C8, the feedback network subunit 26 includes a resistor R8 and a capacitor C9, and the first RC filtering subunit 27 includes a resistor R9 and a capacitor C10;

[0099] One end of the resistor R5 is connected to the first output end of the isolation sampling unit 102, the other end of the resistor R5 is respectively connected to one end of the resistor R7, one end of the capacitor C8 and the first input end of the amplifier U2, one end of the resistor R6 is respectively connected to the second output end of the isolation sampling unit 102, the other end of the resistor R6 is respectively connected to the second input end of the amplifier U2, one end of the capacitor C9 and one end of the resistor R8, the other end of the resistor R7 is respectively connected to the other end of the capacitor C8 and the low-voltage power supply, the other end of the capacitor C9 is respectively connected to the other end of the resistor R8, the output end of the amplifier U2 and one end of the resistor R9, the other end of the resistor R9 is respectively connected to one end of the capacitor C10 and the hardware wave sealing module 20, one end of the capacitor C6 is respectively connected to the second power supply end of the isolation sampling unit 102, the negative electrode of the power supply and one end of the capacitor C7, and the other end of the capacitor C6, the other end of the capacitor C7 and the other end of the capacitor C10 are all grounded.

[0100] It should be noted that capacitors C6 and C10 are filter capacitors, capacitors C7 and C8 are decoupling capacitors, resistors R5, R6, R7 and R8 are voltage divider resistors, amplifier U2 is an operational amplifier, and resistor R9 is a filter resistor. These devices constitute the circuit of the low-voltage side processing unit 103, which can condition the signal transmitted from the previous stage on the low-voltage side of the isolation sampling chip U1, so that the final output current detection signal is within a reasonable voltage range; wherein, the adjustment circuit composed of resistors R5, R6, R7 and R8 can adjust the amplification factor of the amplifier U2.

[0101] For example, Figure 2 and Figure 4 As shown, one end of the resistor R5 is specifically connected to the first output terminal OUTP of the isolation sampling chip U1, one end of the resistor R6 is specifically connected to the output terminal OUTN of the isolation sampling chip U1, one end of the capacitor C6 is specifically connected to the second power supply terminal Vdd2 of the isolation sampling chip U1, and the second ground terminal GND2 of the isolation sampling chip U1 is grounded. The low-voltage power supply can be a +4.5V power supply.

[0102] In this embodiment, the specific working principle is:

[0103] In the high-voltage side processing unit 101, when the current on the power tube flows through the sampling resistors R1 and R2, a differential voltage signal is generated. After the differential voltage signal is filtered by the filter circuit composed of the resistor R3 and the capacitor C2 and the filter circuit composed of the resistor R4 and the capacitor C3, the filtered voltage signal is output to the isolation sampling chip U1; the isolation sampling chip U1 performs the first-stage gain amplification on the received voltage signal and outputs the amplified voltage signal to the low-voltage side processing unit 103; in the low-voltage side processing unit 103, the amplifier U2 performs the second-stage gain amplification on the voltage signal and outputs the second-stage amplified voltage signal, which is filtered by the filter circuit composed of the resistor R9 and the capacitor C10 and finally output as the current detection signal I_S. Among them, adjusting the resistance values ​​of the resistors R5, R6, R7 and R8 can adjust the multiple of the second-stage gain amplification, so that the output current detection signal I_S is within a suitable range to improve the current sampling accuracy of the current detection module 10.

[0104] It can be understood that in the current detection module 10, the delay of the isolation chip U1 and the amplifier U2 is at the nanosecond (ns) level, which can be ignored, so that the main delay of the current detection module 10 comes from the filter circuit composed of the resistor R3 and the capacitor C2, the filter circuit composed of the resistor R4 and the capacitor C3, and the filter circuit composed of the resistor R9 and the capacitor C10. In actual application, the delay of current detection can be shortened by configuring the parameters of the above-mentioned devices, so as to ensure the quality of the current detection signal and keep the current detection delay at a lower level.

[0105] The power tube short-circuit protection circuit provided in this embodiment provides a specific low-latency isolation sampling circuit, which can realize sampling as quickly as possible and output the obtained current detection signal to the hardware wave sealing module so that it can quickly and timely provide short-circuit protection for the power tube against load short circuit; in this circuit, a low-latency current detection module is formed by conventional electronic devices, and the cost is low.

[0106] In another embodiment of the present application, refer to Figure 5 , Figure 5 1 is a circuit schematic diagram of a hardware wave-blocking module in a power tube short-circuit protection circuit. The hardware wave-blocking module 20 includes a comparison unit 301 and a logic unit 302 .

[0107] The comparison unit 301 is connected to the current detection module 10, and is used to compare the current value corresponding to the current detection signal with the preset current threshold corresponding to the reference signal, and output a comparison signal;

[0108] The logic unit 302 is connected to the comparison unit 301 and the control module. The logic unit 302 is used to perform logic and processing according to the comparison signal and the pulse signal to output a driving control signal to the power tube in a normal working state or a protection state.

[0109] It should be noted that the comparison unit 301 can be set with a preset current threshold, which can be a threshold value. When the comparison unit 301 compares that the current flowing through the power tube, that is, the current value corresponding to the current detection signal, exceeds the threshold value, that is, the preset current threshold corresponding to the reference signal, the logic unit 302 can trigger the protection state accordingly, and output a drive control signal to the power tube based on the protection state, and control the power tube to be turned off in the first time to provide short circuit protection.

[0110] In one possible implementation, refer to Figure 6 , Figure 6 for Figure 5 The circuit schematic diagram of the comparison unit in FIG. 301 , the comparison unit 301 may include a current comparison subunit 31, a second RC filter subunit 32, a voltage dividing resistor subunit 33, a second voltage stabilizing subunit 34, a third RC filter subunit 35 and a third voltage stabilizing subunit 36;

[0111] Among them, the first input end of the current comparison subunit 31 is connected to the current detection module 10 through the second RC filter subunit 32, the second input end of the current comparison subunit 31 is respectively connected to one end of the voltage-dividing resistor subunit 33 and one end of the second voltage-stabilizing subunit 34, the other end of the second voltage-stabilizing subunit 34 is connected to the positive pole of the power supply, the output end of the current comparison subunit 31 is respectively connected to one end of the third voltage-stabilizing subunit 36 ​​and the logic unit 302 through the third RC filter subunit 35, the other end of the third voltage-stabilizing subunit 36 ​​is connected to the positive pole of the power supply, and the other end of the voltage-dividing resistor subunit 33 is grounded.

[0112] It should be noted that the second RC filter subunit 32 is used to filter the current detection signal and then input it into the current comparison subunit 31; the voltage-dividing resistor subunit 33 and the second voltage-stabilizing subunit 34 are used to provide a reference signal to the current comparison subunit 31 and provide device protection; the current comparison subunit 31 is used to compare the current value corresponding to the current detection signal with the preset current threshold corresponding to the reference signal, and output a comparison signal; the third RC filter subunit 35 is used to filter the comparison signal and output the filtered comparison signal to the logic unit 302; the third voltage-stabilizing subunit 36 ​​is used to filter the power supply voltage provided by the power supply and provide device protection.

[0113] For example, Figure 5 and Figure 6As shown, the current comparison subunit 31 includes a comparator U3, the second RC filter subunit 32 includes a resistor R10 and a capacitor C11, the voltage dividing resistor subunit 33 includes a resistor R12, the second voltage stabilizing subunit 34 includes a resistor R11 and a capacitor C12, the third RC filter subunit 35 includes a resistor R13 and a capacitor C13, and the third voltage stabilizing subunit 36 ​​includes a resistor R14 and a capacitor C14;

[0114] A first input end of the comparator U3 is respectively connected to one end of the resistor R10 and one end of the capacitor C11, the other end of the resistor R10 is connected to the current detection module 10, a second input end of the comparator U3 is respectively connected to one end of the resistor R12, one end of the resistor R11 and one end of the capacitor C12, the other end of the resistor R11 is respectively connected to the positive electrode of the power supply and the other end of the capacitor C12, the output end of the comparator U3 is respectively connected to one end of the capacitor C13, one end of the resistor R14, one end of the capacitor C14 and the logic unit 302 through the resistor R13, the other end of the resistor R14 is respectively connected to the positive electrode of the power supply and the other end of the capacitor C14, the other end of the resistor R12, the other end of the capacitor C11 and the other end of the capacitor C13 are all grounded.

[0115] It should be noted that the resistors R10 and R13 are filter resistors, the capacitors C11, C12, C13 and C14 are filter capacitors, the resistors R11 and R12 are voltage divider resistors, and the resistor R14 is a pull-up resistor. These components constitute the circuit of the comparison unit 301, which can compare the current value of the current detection signal I_R with a preset current threshold, and then output a comparison signal representing the comparison result to the back-end logic unit 302.

[0116] like Figure 5 and Figure 6 As shown, in the comparison unit 301, the current detection signal I_S is filtered by the filter circuit composed of the resistor R10 and the capacitor C11, and then input to the first input terminal of the comparator U3. After the comparison operation is performed in the comparator U3, the signal output by the comparator U3 is filtered by the filter circuit composed of the resistor R13 and the capacitor C13, and then output as a comparison signal. Figure 5 At point a and point b shown in the figure, when the current detection signal I_S is lower than the level at point a, point b on the output side of the comparator U3 is at a high level, that is, the comparison signal is at a high level; when the current detection signal I_S is higher than the level at point a, point b on the output side of the comparator U3 is at a low level, that is, the comparison signal is at a low level. The level value of point a can be set by setting the resistance values ​​of resistors R11 and R12, that is, the preset current threshold. The level U at point a is a It can be expressed as:

[0117]

[0118] Among them, R 11 Refers to the resistance value of resistor R11, R 12 It refers to the resistance value of the resistor R12. In practical applications, the preset current threshold corresponding to the reference signal to be compared can be adjusted by adjusting these two values.

[0119] It can be understood that in the comparison unit 301, the delay of the comparator U3 is very low and can be ignored, so that the main delay of the comparison unit 301 comes from the filter circuit composed of the resistor R10 and the capacitor C11 and the filter circuit composed of the resistor R13 and the capacitor C13. In practical applications, the delay of the comparison unit 301 can be shortened by configuring the parameters of the above-mentioned devices, so as to ensure the quality of the output comparison signal and make the signal transmission delay of the hardware wave-sealing module 20 at a low level.

[0120] In one possible implementation, refer to Figure 7 , Figure 7 for Figure 5 The circuit schematic diagram of the logic unit in FIG. 302 , the logic unit 302 may include a logic AND subunit 41 , a fourth RC filter subunit 42 , a fifth RC filter subunit 43 and a fifth filter subunit 44 ;

[0121] Among them, the first input end of the logic AND subunit 41 is connected to the comparison unit 301 through the fourth RC filter subunit 42, the second input end of the logic AND subunit 41 is connected to the control module through the fifth RC filter subunit 43, the output end of the logic AND subunit 41 is connected to the power tube, the power end of the logic AND subunit 41 is respectively connected to the positive pole of the power supply and one end of the fifth filter subunit 44, and the ground end of the logic AND subunit 41 and the other end of the fifth filter subunit 44 are both grounded.

[0122] It should be noted that the fourth RC filter subunit 42 is used to filter the received comparison signal, and output the filtered comparison signal to the logic and subunit 41; the fifth RC filter subunit 43 is used to filter the pulse signal, and output the filtered pulse signal to the logic and subunit 41; the logic and subunit 41 is used to perform logic and processing on the filtered comparison signal and the filtered pulse signal, and then output the corresponding drive control signal to the power tube; the fifth filter subunit 44 is used to filter the power supply signal provided by the power supply to the logic and subunit 41, and provide device protection.

[0123] For example, Figure 5 and Figure 7 As shown, the logic and subunit 41 includes a logic and U4, the fourth RC filter subunit 42 includes a resistor R15 and a capacitor C15, the fifth RC filter subunit 43 includes a resistor R16 and a capacitor C16, and the fifth filter subunit 44 includes a capacitor C17;

[0124] The first input end of the logic AND U4 is respectively connected to one end of the resistor R15 and one end of the capacitor C15, the other end of the resistor R15 is connected to the comparison unit 301, the second input end of the logic AND U4 is respectively connected to one end of the resistor R16 and one end of the capacitor C16, the other end of the resistor R16 is connected to the control module, the output end of the logic AND U4 is connected to the power tube, the power supply end of the logic AND U4 is respectively connected to the positive pole of the power supply and one end of the capacitor C17, and the ground end of the logic AND U4, the other end of the capacitor C15, the other end of the capacitor C16 and the other end of the capacitor C17 are all grounded.

[0125] It should be noted that the logic AND U4 is an AND gate logic device, the resistor R15 and the resistor R16 are filter resistors, and the capacitors C15, C16 and C17 are filter capacitors. These devices constitute the AND gate logic processing circuit of the logic unit 302, which can perform logic AND processing on the comparison signal output by the comparison unit 301 and the received pulse signal PWM, so as to realize the corresponding output of the driving control signal PWM_S to the power tube in the normal working state or the protection state.

[0126] like Figure 5 and Figure 7 As shown, in the logic unit 302, the comparison signal is filtered by the filter circuit composed of resistor R15 and capacitor C15, and then input to port 1 of the logic and U4, i.e., the first input terminal. At the same time, the pulse signal PWM provided by the control module such as MCU is filtered by the filter circuit composed of resistor R16 and capacitor C16, and then input to port 2 of the logic and U4, i.e., the second input terminal. After logic processing in the logic and U4, the drive control signal PWM_S is outputted correspondingly through port 3 of the logic and U4, i.e., the output terminal. Specifically, when the comparison signal outputted by the comparison unit 301 indicates that the current value corresponding to the current detection signal exceeds the preset current threshold corresponding to the reference signal, the level at point b is low, and the logic and U4 will pull down the output drive control signal PWM_S, which can cut off the drive control of the power tube and turn it off.

[0127] It can be understood that the delay of the AND gate logic device is very low and can be ignored, so that the main delay of the logic unit 302 comes from the filter circuit composed of the resistor R15 and the capacitor C15. In actual application, the delay of the logic unit 302 can be shortened by configuring the parameters of the above devices, so as to ensure the quality of the output drive control signal PWM_S and further reduce the signal transmission delay of the hardware wave-sealing module 20.

[0128] In this embodiment, the specific working principle is:

[0129] When the MCU normally sends out the pulse signal PWM, the power tube driving circuit 2 works normally, the load works normally, the current on the power tube does not exceed the preset current threshold, the level at point b is high, and the drive control signal PWM_S output by the logic AND U4 will follow the pulse signal PWM, thereby realizing normal on-off control of the power tube;

[0130] When the load is abnormally short-circuited, the current on the power tube will exceed the preset current threshold, the level at point b will be low, and the drive control signal PWM_S output by the logic and U4 will be pulled low, thereby achieving hardware blocking and protecting the power tube.

[0131] The power tube short-circuit protection circuit provided in this embodiment provides a hardware wave-blocking logic circuit that is specifically implemented through hardware and can block the wave in advance compared to the control module. Compared with the method of using MCU to implement short-circuit protection in related technologies, the drive control signal of the power tube can be cut off in advance to ensure timely protection of the power tube. In this circuit, a hardware wave-blocking module with comparison and wave-blocking functions is constructed through conventional electronic devices, thereby achieving more reliable short-circuit protection at a lower cost.

[0132] The present application also proposes a control method for a power tube short-circuit protection circuit.

[0133] In one embodiment of the present application, refer to Figure 8 , Figure 8 The present invention is a flow chart of an embodiment of a control method for a power tube short-circuit protection circuit, wherein the power tube short-circuit protection circuit may be a power tube short-circuit protection circuit of any of the above embodiments, and the control method may include steps S10 to S40:

[0134] Step S10, when the power tube driving circuit is working, the current flowing through the power tube in the power tube driving circuit is sampled in real time by the current detection module, and a current detection signal is output;

[0135] Step S20, comparing the current detection signal with the reference signal through the hardware wave-sealing module to determine whether there is overcurrent in the power tube according to the comparison result;

[0136] Step S30, if there is no overcurrent, the hardware wave-sealing module enters a normal working state following the change of the received pulse signal, and outputs a corresponding driving control signal to the power tube to enable the power tube to work normally;

[0137] Step S40: If there is an overcurrent, the hardware wave-sealing module triggers a protection state of the received pulse signal wave-sealing, and outputs a corresponding drive control signal to the power tube to provide short-circuit protection for the power tube.

[0138] In a feasible implementation manner, the power tube short-circuit protection circuit further includes a control module; after step S10, the control method may further include step S50:

[0139] Step S50, when the control module identifies an overcurrent fault based on the current detection signal, the pulse signal is blocked and the blocked pulse signal is output, so that the hardware blocking module follows the changes of the received blocked pulse signal and outputs the blocked drive control signal to the power tube.

[0140] Correspondingly, after step S40, the control method may further include steps S60 to S70:

[0141] Step S60, returning to step S10 of sampling the current flowing through the power tube in the power tube driving circuit in real time through the current detection module and outputting a current detection signal, so as to continue to determine whether there is an overcurrent in the power tube;

[0142] Specifically, the current detection module continuously samples the current flowing through the power tube, and correspondingly continuously outputs the current detection signal to the hardware wave-sealing module, so that the hardware wave-sealing module continues to compare the current detection signal with the reference signal to continue to determine whether there is an overcurrent in the power tube;

[0143] Step S70, if there is no overcurrent, the hardware wave-sealing module enters the normal working state, follows the change of the received pulse signal after wave-sealing, and outputs the driving control signal after wave-sealing to the power tube to provide secondary short-circuit protection for the power tube.

[0144] It should be noted that the specific structure of the power tube short-circuit protection circuit refers to the above-mentioned embodiment. Since the control method of the power tube short-circuit protection circuit adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0145] The above are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A power tube short circuit protection circuit, It is characterized in that Connected to the power tube driving circuit, the power tube short-circuit protection circuit includes: A current detection module, connected to the power tube drive circuit, the current detection module is used to sample the current flowing through the power tube in the power tube drive circuit in real time and output a current detection signal; A hardware wave-sealing module is connected to the current detection module and the power tube drive circuit respectively. The hardware wave-sealing module is used to compare the current detection signal with a reference signal, and enter a normal working state that follows the changes of the received pulse signal or trigger a protection state for sealing the received pulse signal according to the comparison result, and output a corresponding drive control signal to the power tube.

2. The power tube short-circuit protection circuit as claimed in claim 1, It is characterized in that The power tube short-circuit protection circuit also includes: A control module, connected to the current detection module and the hardware wave-sealing module respectively, for outputting the pulse signal to the hardware wave-sealing module, and when an overcurrent fault is identified according to the current detection signal, sealing the pulse signal and outputting the sealed pulse signal; The hardware wave-enclosing module is also used to enter a secondary protection state following the change of the received pulse signal after the wave-enclosing according to the comparison result, and output a corresponding drive control signal to the power tube.

3. The power tube short-circuit protection circuit according to claim 1 or 2, It is characterized in that The current detection module comprises: A high-voltage side processing unit connected to the current detection module, the high-voltage side processing unit is used to sample the current flowing through the power tube in the power tube driving circuit in real time, generate a sampling signal, and output the sampling signal after filtering; An isolation sampling unit, connected to the high-voltage side processing unit, the isolation sampling unit is used to provide electrical isolation and output the received sampling signal; The low-voltage side processing unit is connected to the isolation sampling unit and the hardware wave-sealing module respectively, and the low-voltage side processing unit is used to amplify and filter the received sampling signal and output the current detection signal.

4. The power tube short-circuit protection circuit as claimed in claim 3, It is characterized in that The high-voltage side processing unit includes a current sampling subunit, a first filtering subunit, a second filtering subunit, an absorption capacitor subunit, a third filtering subunit and a first decoupling subunit; One end of the current sampling subunit is respectively connected to the power tube driving circuit and the input end of the first filtering subunit, the power tube driving circuit is connected to the positive DC bus, the other end of the current sampling subunit is respectively connected to the negative DC bus and the input end of the second filtering subunit, the output end of the first filtering subunit is respectively connected to one end of the absorption capacitor subunit and the first input end of the isolation sampling unit, the output end of the second filtering subunit is respectively connected to the other end of the absorption capacitor subunit and the second input end of the isolation sampling unit, one end of the third filtering subunit is respectively connected to the positive pole of the power supply, one end of the first decoupling subunit and the first power supply end of the isolation sampling unit, the ground end of the first filtering subunit, the ground end of the second filtering subunit, the other end of the third filtering subunit, the other end of the first decoupling subunit and the first ground end of the isolation sampling unit are all connected to the negative DC bus.

5. The power tube short-circuit protection circuit as claimed in claim 4, It is characterized in that The current sampling subunit includes a resistor R1 and a resistor R2, the first filtering subunit includes a resistor R3 and a capacitor C2, the second filtering subunit includes a resistor R4 and a capacitor C3, the absorption capacitor subunit includes a capacitor C1, the third filtering subunit includes a capacitor C4, and the first decoupling subunit includes a capacitor C5; One end of the resistor R1 is respectively connected to the power tube driving circuit, one end of the resistor R2 and one end of the resistor R3; the other end of the resistor R1 is respectively connected to the negative DC bus, the other end of the resistor R2 and one end of the resistor R4; the other end of the resistor R3 is respectively connected to one end of the capacitor C1, one end of the capacitor C2 and the first input end of the isolation sampling unit; the other end of the resistor R4 is respectively connected to the other end of the capacitor C1, one end of the capacitor C3 and the second input end of the isolation sampling unit; one end of the capacitor C4 is respectively connected to the positive electrode of the power supply, one end of the capacitor C5 and the first power supply end of the isolation sampling unit; the other end of the capacitor C2, the other end of the capacitor C3, the other end of the capacitor C4 and the other end of the capacitor C5 are all connected to the negative DC bus.

6. The power tube short-circuit protection circuit as claimed in claim 3, It is characterized in that The low-voltage side processing unit includes a signal amplification subunit, a fourth filtering subunit, a second decoupling subunit, a voltage divider network subunit, a first voltage stabilization subunit, a feedback network subunit and a first RC filtering subunit; The positive input end of the voltage divider network subunit is connected to the first output end of the isolation sampling unit, the positive output end of the voltage divider network subunit is respectively connected to the first input end of the signal amplification subunit and one end of the first voltage stabilizing subunit, the other end of the first voltage stabilizing subunit is connected to a low-voltage power supply, the negative input end of the voltage divider network subunit is connected to the second output end of the isolation sampling unit, the negative output end of the voltage divider network subunit is respectively connected to the second input end of the signal amplification subunit and one end of the feedback network subunit, the other end of the feedback network subunit is respectively connected to the output end of the signal amplification subunit and one end of the first RC filtering subunit, the other end of the first RC filtering subunit is connected to the hardware wave-sealing module, one end of the fourth filtering subunit is respectively connected to the second power supply end of the isolation sampling unit, the negative pole of the power supply and one end of the second decoupling subunit, the second grounding end of the isolation sampling unit, the other end of the fourth filtering subunit and the other end of the second decoupling subunit are all grounded.

7. The power tube short-circuit protection circuit as claimed in claim 6, It is characterized in that The signal amplification subunit includes an amplifier U2, the fourth filtering subunit includes a capacitor C6, the second decoupling subunit includes a capacitor C7, the voltage divider network subunit includes a resistor R5 and a resistor R6, the first voltage stabilization subunit includes a resistor R7 and a capacitor C8, the feedback network subunit includes a resistor R8 and a capacitor C9, and the first RC filtering subunit includes a resistor R9 and a capacitor C10; One end of the resistor R5 is connected to the first output end of the isolation sampling unit, the other end of the resistor R5 is respectively connected to one end of the resistor R7, one end of the capacitor C8 and the first input end of the amplifier U2, one end of the resistor R6 is respectively connected to the second output end of the isolation sampling unit, the other end of the resistor R6 is respectively connected to the second input end of the amplifier U2, one end of the capacitor C9 and one end of the resistor R8, the other end of the resistor R7 is respectively connected to the other end of the capacitor C8 and a low-voltage power supply, the other end of the capacitor C9 is respectively connected to the other end of the resistor R8, the output end of the amplifier U2 and one end of the resistor R9, the other end of the resistor R9 is respectively connected to one end of the capacitor C10 and the hardware wave sealing module, one end of the capacitor C6 is respectively connected to the second power supply end of the isolation sampling unit, the negative electrode of the power supply and one end of the capacitor C7, and the other end of the capacitor C6, the other end of the capacitor C7 and the other end of the capacitor C10 are all grounded.

8. The power tube short-circuit protection circuit according to claim 1 or 2, It is characterized in that The hardware wave-sealing module comprises: A comparison unit connected to the current detection module, the comparison unit is used to compare the current value corresponding to the current detection signal with the preset current threshold corresponding to the reference signal, and output a comparison signal; A logic unit is connected to the comparison unit and the control module, and is used to perform logic and processing according to the comparison signal and the pulse signal to output the drive control signal to the power tube in the normal working state or the protection state.

9. The power tube short-circuit protection circuit as claimed in claim 8, It is characterized in that The comparison unit includes a current comparison subunit, a second RC filter subunit, a voltage-dividing resistor subunit, a second voltage-stabilizing subunit, a third RC filter subunit and a third voltage-stabilizing subunit; The first input end of the current comparison subunit is connected to the current detection module through the second RC filter subunit, the second input end of the current comparison subunit is respectively connected to one end of the voltage-dividing resistor subunit and one end of the second voltage-stabilizing subunit, the other end of the second voltage-stabilizing subunit is connected to the positive pole of the power supply, the output end of the current comparison subunit is respectively connected to one end of the third voltage-stabilizing subunit and the logic unit through the third RC filter subunit, the other end of the third voltage-stabilizing subunit is connected to the positive pole of the power supply, and the other end of the voltage-dividing resistor subunit is grounded.

10. The power tube short-circuit protection circuit as claimed in claim 9, It is characterized in that The current comparison subunit includes a comparator U3, the second RC filter subunit includes a resistor R10 and a capacitor C11, the voltage dividing resistor subunit includes a resistor R12, the second voltage stabilizing subunit includes a resistor R11 and a capacitor C12, the third RC filter subunit includes a resistor R13 and a capacitor C13, and the third voltage stabilizing subunit includes a resistor R14 and a capacitor C14; The first input end of the comparator U3 is respectively connected to one end of the resistor R10 and one end of the capacitor C11, the other end of the resistor R10 is connected to the current detection module, the second input end of the comparator U3 is respectively connected to one end of the resistor R12, one end of the resistor R11 and one end of the capacitor C12, the other end of the resistor R11 is respectively connected to the positive electrode of the power supply and the other end of the capacitor C12, the output end of the comparator U3 is respectively connected to one end of the capacitor C13, one end of the resistor R14, one end of the capacitor C14 and the logic unit through the resistor R13, the other end of the resistor R14 is respectively connected to the positive electrode of the power supply and the other end of the capacitor C14, the other end of the resistor R12, the other end of the capacitor C11 and the other end of the capacitor C13 are all grounded.

11. The power tube short-circuit protection circuit as claimed in claim 8, It is characterized in that The logic unit includes a logic and sub-unit, a fourth RC filter sub-unit, a fifth RC filter sub-unit and a fifth filter sub-unit; The first input end of the logic and subunit is connected to the comparison unit through the fourth RC filter subunit, the second input end of the logic and subunit is connected to the control module through the fifth RC filter subunit, the output end of the logic and subunit is connected to the power tube, the power end of the logic and subunit is respectively connected to the positive pole of the power supply and one end of the fifth filter subunit, and the ground end of the logic and subunit and the other end of the fifth filter subunit are both grounded.

12. The power tube short-circuit protection circuit according to claim 11, It is characterized in that The logic and sub-unit includes a logic and U4, the fourth RC filter sub-unit includes a resistor R15 and a capacitor C15, the fifth RC filter sub-unit includes a resistor R16 and a capacitor C16, and the fifth filter sub-unit includes a capacitor C17; The first input end of the logic AND U4 is respectively connected to one end of the resistor R15 and one end of the capacitor C15, the other end of the resistor R15 is connected to the comparison unit, the second input end of the logic AND U4 is respectively connected to one end of the resistor R16 and one end of the capacitor C16, the other end of the resistor R16 is connected to the control module, the output end of the logic AND U4 is connected to the power tube, the power supply end of the logic AND U4 is respectively connected to the positive pole of the power supply and one end of the capacitor C17, the ground end of the logic AND U4, the other end of the capacitor C15, the other end of the capacitor C16 and the other end of the capacitor C17 are all grounded.

13. A control method for a power tube short-circuit protection circuit, It is characterized in that The power tube short-circuit protection circuit is a power tube short-circuit protection circuit as claimed in any one of claims 1 to 12, and the control method comprises: When the power tube driving circuit is working, the current flowing through the power tube in the power tube driving circuit is sampled in real time through the current detection module, and a current detection signal is output; The current detection signal is compared with a reference signal by a hardware wave-sealing module, so as to determine whether there is an overcurrent in the power tube according to the comparison result; If there is no overcurrent, the hardware wave-sealing module enters a normal working state following the change of the received pulse signal, and outputs a corresponding driving control signal to the power tube to enable the power tube to work normally; If there is an overcurrent, the hardware wave-sealing module triggers a protection state of the received pulse signal wave-sealing, and outputs a corresponding drive control signal to the power tube to provide short-circuit protection for the power tube.

14. The control method of the power tube short-circuit protection circuit according to claim 13, It is characterized in that The power tube short-circuit protection circuit further includes a control module. After the current detection module samples the current flowing through the power tube in the power tube driving circuit in real time and outputs a current detection signal, the control method further includes: When an overcurrent fault is identified according to the current detection signal, the control module blocks the pulse signal and outputs the blocked pulse signal, so that the hardware blocking module follows the changes of the received blocked pulse signal and outputs the blocked drive control signal to the power tube.

15. The control method of the power tube short-circuit protection circuit according to claim 14, It is characterized in that After the step of triggering the protection state of the received pulse signal encapsulation by the hardware encapsulation module and outputting the corresponding drive control signal to the power tube to provide short-circuit protection for the power tube, the control method further includes: Returning to the step of sampling the current flowing through the power tube in the power tube driving circuit in real time through the current detection module and outputting a current detection signal, so as to continue to determine whether there is an overcurrent in the power tube; If there is no overcurrent, the hardware wave-sealing module enters the normal working state, follows the changes of the received pulse signal after wave-sealing, and outputs the drive control signal after wave-sealing to the power tube to provide secondary short-circuit protection for the power tube.

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