Short-circuit protection circuit

Abstract

The present invention discloses a short-circuit protection circuit, which belongs to the field of short-circuit protection circuits. The circuit can perform short-circuit protection on an H-bridge controlled by a half-bridge pre-driver chip and has a fast response speed. The short-circuit protection circuit of the present invention comprises a drive circuit composed of four MOS tubes, a half-bridge pre-driver circuit composed of a half-bridge pre-driver chip a and a half-bridge pre-driver chip b, wherein the half-bridge pre-driver chip a is connected to two MOS tubes, and the half-bridge pre-driver chip b is connected to the other two MOS tubes. The circuit also comprises an MCU signal circuit connected to the half-bridge pre-driver circuit and sending a PWM signal to the half-bridge pre-driver circuit. The circuit also comprises a short-circuit processing circuit connected to the half-bridge pre-driver circuit, a sampling resistor for sampling the current generated by the drive circuit and converting it into a voltage signal, and a short-circuit judgment circuit connected to the sampling resistor and the short-circuit processing circuit and for judging the voltage signal obtained by the sampling resistor and, in the event of a short circuit, causing the entire circuit to enter a protection state through the short-circuit processing circuit.

Description

Technical field

[0001] The present invention relates to the field of short circuit protection circuits, and in particular to a short circuit protection circuit. [Background Technology]

[0002] Controlling a brushed DC motor requires some control circuits. One of these control circuits is the H-bridge circuit, which consists of four MOS tubes. Since the internal resistance of the MOS tube is small, when the output line is short-circuited, a very large current will be generated in the loop, which will burn out the MOS.

[0003] The general solution is to use an integrated pre-driver chip, which has the ability to generate PWM signals to control four MOSs and has current detection capabilities to achieve short-circuit protection functions, but the integrated pre-driver chip is expensive; or use a lower-priced half-bridge pre-driver chip. Two half-bridge pre-driver chips can control an H-bridge circuit composed of four MOSs, and the pre-driver cost of one H-bridge is only about 1 / 5 of that of an integrated pre-driver chip. However, the half-bridge pre-driver chip lacks short-circuit protection functions. Generally, the MCU samples the current and then performs protection. However, the MCU needs a certain period of time to collect current, and the time often exceeds the time that the MOS can withstand, causing the MOS to burn out. [Summary of the invention]

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and propose a short-circuit protection circuit, which can perform short-circuit protection on the H-bridge controlled by the half-bridge pre-driver chip and has a fast response speed.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The short-circuit protection circuit includes a drive circuit composed of four MOS tubes, a half-bridge pre-driver circuit composed of a half-bridge pre-driver chip a and a half-bridge pre-driver chip b, wherein the half-bridge pre-driver chip a is connected to two MOS tubes, and the half-bridge pre-driver chip b is connected to another two MOS tubes. The circuit also includes an MCU signal circuit connected to the half-bridge pre-driver circuit to send a PWM signal to the half-bridge pre-driver circuit. The circuit also includes a short-circuit processing circuit connected to the half-bridge pre-driver circuit, a sampling resistor for sampling the current generated by the drive circuit and converting it into a voltage signal, and a short-circuit judgment circuit connected to the sampling resistor and the short-circuit processing circuit for judging the voltage signal obtained by the sampling resistor and causing the entire circuit to enter a protection state through the short-circuit processing circuit in the event of a short circuit.

[0007] Furthermore, the short-circuit protection circuit also includes a self-locking feedback circuit connected to the short-circuit judgment circuit, which is used to lock the protection state and transmit the protection state signal to the MCU signal circuit to alert the user.

[0008] Furthermore, the self-locking feedback circuit includes a PNP-type transistor a, the short-circuit judgment circuit includes an NPN-type transistor b, the C pole of the transistor a is connected to the B pole of the transistor b, and the E pole of the transistor a is connected to the C pole of the transistor b.

[0009] Furthermore, the short-circuit judgment circuit further includes a resistor R1 and a capacitor C1 connected in parallel, which are used for filtering and adjusting the response time of the short-circuit protection.

[0010] Furthermore, the short-circuit processing circuit includes a short-circuit processing module a, a short-circuit processing module b and a short-circuit processing module c. The short-circuit processing module b is connected to the half-bridge pre-driver chip a, and the short-circuit processing module c is connected to the half-bridge pre-driver chip b. The short-circuit processing module a is simultaneously connected to the short-circuit processing module b and the short-circuit processing module c to simultaneously control the half-bridge pre-driver chip a and the half-bridge pre-driver chip b.

[0011] Furthermore, the short-circuit processing module a includes a transistor Qa, the short-circuit processing module b includes a transistor Qb, and the short-circuit processing module c includes a transistor Qc. The transistor Qa is a PNP type, and the transistor Qb and the transistor Qc are NPN types. The C pole of the transistor Qa is connected to the B pole of the transistor Qb and the transistor Qc, and the C pole of the transistor Qb and the C pole of the transistor Qc are connected to the MCU signal circuit, so that the PWM signal emitted by the MCU signal circuit is maintained at a low level in the event of a short circuit.

[0012] Furthermore, the short-circuit processing circuit connects the PWM signal emitted by the MCU signal circuit to the short-circuit judgment circuit, so as to maintain the PWM signal emitted by the MCU signal circuit at a low level when a short circuit occurs.

[0013] Furthermore, the short-circuit processing circuit includes a diode Da and a diode Db, the positive pole of the diode Da is connected to the MCU signal circuit and the half-bridge pre-driver chip a, the positive pole of the diode Db is connected to the MCU signal circuit and the half-bridge pre-driver chip b, and the negative poles of the diode Da and the diode Db are connected to the short-circuit judgment circuit.

[0014] Furthermore, the short-circuit processing circuit includes an input power supply VCCA and an output power supply VCCB. The short-circuit processing circuit connects the output power supply VCCB to the half-bridge pre-driver circuit and supplies power to it, so as to cut off the output power supply VCCB in the event of a short circuit, causing the half-bridge pre-driver circuit to lose power supply and enter low-voltage protection.

[0015] Furthermore, the short-circuit processing circuit includes an NPN-type transistor Ma and a PNP-type transistor Mb, the B pole of the transistor Ma is connected to the short-circuit judgment circuit, the C pole of the transistor Ma is connected to the B pole of the transistor Mb, the input power supply VCCA is connected to the E pole of the transistor Mb, and the C pole of the transistor Mb outputs the output power supply VCCB.

[0016] Beneficial effects of the present invention:

[0017] The short-circuit protection circuit proposed by the present invention has an H-bridge circuit as its driving circuit, and a half-bridge pre-driver circuit can control the H-bridge circuit. The current in the driving circuit is collected by a sampling resistor, the current signal is converted into a voltage signal, and the voltage signal is sent to the short-circuit judgment circuit. The short-circuit judgment circuit judges the voltage signal. When a short circuit occurs, the current generated is too large. The short-circuit judgment circuit can judge that the collected current exceeds the threshold value, and then the short-circuit processing circuit is used to put the entire circuit into a protection state, thereby realizing short-circuit protection in the H-bridge circuit controlled by the half-bridge pre-driver chip. In this way, there is no need to use the MCU signal circuit to sample the current for protection, and the response time is faster, so that the MOS tube in the driving circuit will not burn out.

[0018] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings.

Brief Description of the Drawings

[0019] The present invention will be further described below with reference to the accompanying drawings:

[0020] Figure 1 FIG1 is a circuit diagram A of a short-circuit protection circuit according to an embodiment of the present invention;

[0021] Figure 2 for Figure 1 The connection diagram of transistor a and transistor b;

[0022] Figure 3 FIG1 is a circuit diagram B of a short-circuit protection circuit according to an embodiment of the present invention;

[0023] Figure 4 FIG3 is a circuit diagram C of a short-circuit protection circuit according to an embodiment of the present invention;

[0024] Figure 5 for Figure 4 A magnified view of the short-circuit handling circuit. [Specific implementation method]

[0025] The following is an explanation and description of the technical solutions of the embodiments of the present invention in conjunction with the drawings of the embodiments of the present invention. However, the following embodiments are only preferred embodiments of the present invention and are not exhaustive. Based on the embodiments in the implementation manner, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise explicitly specified.

[0028] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0029] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0030] Reference Figure 1 and Figure 2An embodiment of the present invention provides a short-circuit protection circuit, comprising a drive circuit composed of four MOS transistors, a half-bridge pre-driver circuit composed of a half-bridge pre-driver chip a and a half-bridge pre-driver chip b, wherein the half-bridge pre-driver chip a is connected to two MOS transistors, and the half-bridge pre-driver chip b is connected to another two MOS transistors; a short-circuit processing circuit connected to the half-bridge pre-driver circuit; a sampling resistor for sampling the current generated by the drive circuit and converting it into a voltage signal; a short-circuit judgment circuit connected to the sampling resistor and the short-circuit processing circuit for judging the voltage signal obtained by the sampling resistor and, in the event of a short circuit, for putting the entire circuit into a protection state through the short-circuit processing circuit; and an MCU signal circuit connected to the short-circuit processing circuit and the half-bridge pre-driver circuit for sending a PWM signal to the half-bridge pre-driver circuit. The half-bridge pre-driver circuit converts the PWM signal provided by the MCU into a voltage signal for driving the MOS transistors in the drive circuit, and is used to process the voltage signal transmitted by the short-circuit processing circuit.

[0031] The short-circuit protection circuit proposed in the present invention is an H-bridge circuit as the driving circuit. The half-bridge pre-driver circuit can control the H-bridge circuit, collect the current in the driving circuit through the sampling resistor, convert the current signal into a voltage signal, and send the voltage signal to the short-circuit judgment circuit. The voltage signal is also amplified by the operational amplifier and then sent to the MCU for voltage collection (this part is not drawn in the figure). The short-circuit judgment circuit judges the voltage signal. When a short circuit occurs, the current generated is too large. The short-circuit judgment circuit can judge that the collected current exceeds the threshold, and then the short-circuit processing circuit is used to put the entire circuit into a protection state, thereby realizing short-circuit protection in the H-bridge circuit controlled by the half-bridge pre-driver chip. In this way, there is no need to use the MCU signal circuit to sample the current for protection, and the response time is faster, so that the MOS tube in the driving circuit will not burn out.

[0032] Furthermore, the short-circuit protection circuit also includes a self-locking feedback circuit connected to the short-circuit detection circuit, which is used to lock the protection state and transmit the protection state signal to the MCU signal circuit to alert the user. The self-locking feedback circuit includes a PNP-type transistor a, and the short-circuit detection circuit includes an NPN-type transistor b. The C terminal of transistor a is connected to the B terminal of transistor b, and the E terminal of transistor a is connected to the C terminal of transistor b. When the self-locking feedback circuit is locked, the MCU signal circuit recognizes it as a low level; when it is not locked, it is a high level.

[0033] The short-circuit detection circuit also includes a parallel resistor R1 and capacitor C1, which are used for filtering and adjusting the short-circuit protection response time. After filtering through resistor R1 and capacitor C1, the voltage is applied to the B terminal of transistor a. If the voltage exceeds the limit, transistor a turns on. The response time can be adjusted by adjusting the values ​​of resistor R1 and capacitor C1.

[0034] The short-circuit detection circuit filters the voltage signal and applies it to the B terminal of transistor b. When the voltage received at the B terminal exceeds the transistor turn-on voltage of transistor b, transistor b turns on, activating the short-circuit protection circuit and the self-locking feedback circuit. The self-locking circuit composed of transistors a and b can achieve a self-locking state. Simply put, after transistor a turns on, it applies a high voltage to the B terminal of transistor b, turning on transistor b. This, in turn, pulls down the B terminal of transistor a, turning on transistor a, thus forming a self-locking state. The low voltage at the E terminal of transistor a is recognized by the MCU signal circuit as a low level, as opposed to the high level when the self-locking state is not established, thus notifying the MCU signal circuit that the circuit has entered short-circuit protection. The MCU signal circuit can then pull down the E terminal of transistor a to a lower level, breaking the self-locking state of transistors a and b and returning them to their initial state, where both transistors are off.

[0035] Specifically, the self-locking feedback circuit is connected to the power supply VCC0. Since transistor b is turned on, the B terminal of transistor a is pulled low, causing transistor a to be turned on. Since the B terminal of transistor b is clamped at approximately 0.7V by the BE terminal of transistor b, the voltage difference between EC when transistor a is turned on is approximately 0.2V. Ultimately, the MCU signal circuit can receive a voltage of approximately 0.9V, which is considered to be a low level. When transistor a is not turned on (that is, when short-circuit protection is not in effect), the voltage received by the MCU signal circuit is approximately the voltage of the power supply VCC0, which is considered to be a high level. In this way, the two states are distinguished, so the short-circuit state can be fed back to the MCU signal circuit, and the user is informed to perform relevant inspections.

[0036] When transistor b is conducting, VCC0 can maintain transistor a's BE above the conduction voltage via transistor b's EC, eliminating the need for a voltage generated by a sampling resistor to maintain conduction. This achieves self-locking, preventing the protection from being lost due to the disappearance of short-circuit current. The self-locking feedback circuit also includes resistor R2 and capacitor C2 in parallel. When the MCU signal circuit needs to cancel the short-circuit protection state, it only needs to pull transistor b's E terminal down to close to 0V for a period of time. This way, no voltage can maintain transistor a's BE above the conduction voltage, causing transistor a to be non-conducting. When the MCU no longer pulls it down, transistor b's B terminal is pulled up to VCC3 by resistor R2. As a result, transistor b's BE does not exceed the conduction voltage, and transistor b is non-conducting, thus achieving unlocking. Capacitor C2 maintains the voltage at transistor b's B terminal stable during the initial power-up or unlocking process.

[0037] Preferably, the short-circuit processing circuit includes a short-circuit processing module a, a short-circuit processing module b and a short-circuit processing module c. The short-circuit processing module b is connected to the half-bridge pre-driver chip a, the short-circuit processing module c is connected to the half-bridge pre-driver chip b, and the short-circuit processing module a is simultaneously connected to the short-circuit processing module b and the short-circuit processing module c to simultaneously control the half-bridge pre-driver chip a and the half-bridge pre-driver chip b. The short-circuit processing module a includes a transistor Qa, the short-circuit processing module b includes a transistor Qb, and the short-circuit processing module c includes a transistor Qc. The transistor Qa is a PNP type, and the transistor Qb and the transistor Qc are NPN types. The C pole of the transistor Qa is connected to the B pole of the transistor Qb and the transistor Qc, and the C pole of the transistor Qb and the C pole of the transistor Qc are connected to the MCU signal circuit, so that the PWM signal emitted by the MCU signal circuit is maintained at a low level when a short circuit occurs.

[0038] The short-circuit protection circuit of this embodiment pulls down the PWM signal of the MCU signal circuit through transistors Qb and Qc. Specifically, when transistor a is turned on, transistor Qa transmits the VCC0 voltage to transistors Qb and Qc, turning them on. This maintains the PWM signal from the MCU signal circuit at a low level, causing the half-bridge pre-driver chip to stop converting the MCU's PWM signal into a signal that drives the MOS. This directly cuts off the input signal to the half-bridge pre-driver chip, halting its output. This provides extremely fast response, achieving protection in less than a single PWM pulse.

[0039] In the above embodiment, a method of pulling down the PWM signal of the MCU signal circuit to achieve short circuit protection is proposed. Figure 3 In another embodiment of the present invention, another short-circuit processing circuit capable of pulling down the PWM signal is proposed. Specifically:

[0040] The short-circuit processing circuit connects the PWM signal emitted by the MCU signal circuit to the short-circuit judgment circuit to maintain the PWM signal emitted by the MCU signal circuit at a low level when a short circuit occurs. The short-circuit processing circuit includes a diode Da and a diode Db. The positive pole of the diode Da is connected to the MCU signal circuit and the half-bridge pre-driver chip a, the positive pole of the diode Db is connected to the MCU signal circuit and the half-bridge pre-driver chip b, and the negative poles of the diodes Da and Db are connected to the short-circuit judgment circuit.

[0041] The short-circuit handling circuit of this embodiment uses diodes Da and Db to pull down the PWM signal of the MCU signal circuit. Specifically, diodes Da and Db connect the PWM signal of the MCU signal circuit to transistor a of the short-circuit determination circuit, maintaining the PWM signal of the MCU signal circuit at a low level when transistor a is turned on. This circuit directly pulls down the PWM signal through diodes, requiring fewer components than the aforementioned preferred solution. However, because the voltage drop of the diodes is higher than the conduction voltage drop of the transistors, the PWM signal cannot be pulled down to a very low level. Under certain interference conditions, the half-bridge pre-driver circuit may mistakenly recognize a high level, causing the voltage of the MOS transistor in the control drive circuit to continue to be generated.

[0042] Reference Figure 4 and Figure 5 Different from the above embodiment, in another embodiment of the present invention, another short-circuit processing circuit is proposed to achieve short-circuit protection by cutting off the power supply voltage of the half-bridge pre-driver circuit. Specifically:

[0043] The short-circuit processing circuit includes an input power supply VCCA and an output power supply VCCB. The short-circuit processing circuit connects the output power supply VCCB to the half-bridge pre-driver circuit and supplies power to it, so as to cut off the output power supply VCCB in the event of a short circuit, causing the half-bridge pre-driver circuit to lose power and enter low-voltage protection. The short-circuit processing circuit includes an NPN-type transistor Ma and a PNP-type transistor Mb. The B pole of the transistor Ma is connected to the short-circuit judgment circuit, the C pole of the transistor Ma is connected to the B pole of the transistor Mb, the input power supply VCCA is connected to the E pole of the transistor Mb, and the C pole of the transistor Mb outputs the output power supply VCCB.

[0044] In this embodiment, the short-circuit processing circuit cuts off the power supply voltage of the half-bridge pre-driver chip in the half-bridge pre-driver circuit, so that the half-bridge pre-driver circuit no longer outputs the voltage for controlling the MOS transistor in the driver circuit. Specifically, in this circuit, the output power supply VCCB is provided by the input power supply VCCA through the transistor Mb. When short-circuit protection occurs, the short-circuit protection processing circuit turns off the transistor Ma, causing the transistor Mb to turn off, thereby cutting off the output power supply VCCB, causing the half-bridge pre-driver circuit to lose power and enter low-voltage protection, and stop outputting the control voltage to the MOS transistor in the driver circuit, thereby achieving the purpose of short-circuit protection.

[0045] The short-circuit protection circuit proposed in this embodiment achieves protection by controlling the power supply to the half-bridge pre-driver circuit. Its response time is affected by the VCCB voltage drop time and the low-voltage protection response time of the half-bridge pre-driver chip within the half-bridge pre-driver circuit. This prolongs the time it takes for the entire circuit to respond to short-circuit protection, preventing the rapid protection offered by the preferred solution. This results in a relatively high current when protection is complete. This circuit minimizes component count requirements for multiple motor outputs, provided the components can withstand these requirements.

[0046] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art will understand that the present invention includes, but is not limited to, the contents described in the drawings and the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are intended to be included within the scope of the claims.

Claims

1. A short-circuit protection circuit comprising a drive circuit consisting of four MOS transistors, a half-bridge pre-driver circuit consisting of a half-bridge pre-driver chip a and a half-bridge pre-driver chip b, wherein the half-bridge pre-driver chip a is connected to two MOS transistors, and the half-bridge pre-driver chip b is connected to another two MOS transistors, and further comprising an MCU signal circuit connected to the half-bridge pre-driver circuit to send a PWM signal to the half-bridge pre-driver circuit, characterized in that: It also includes a short-circuit processing circuit connected to the half-bridge pre-drive circuit, a sampling resistor for sampling the current generated by the drive circuit and converting it into a voltage signal, and a short-circuit judgment circuit connected to the sampling resistor and the short-circuit processing circuit, for judging the voltage signal obtained by the sampling resistor and causing the entire circuit to enter a protection state through the short-circuit processing circuit when a short circuit occurs; the short-circuit protection circuit also includes a self-locking feedback circuit connected to the short-circuit judgment circuit, for locking the protection state and transmitting the protection state signal to the MCU signal circuit to alert the user; the self-locking feedback circuit includes a PNP-type transistor a, and the short-circuit judgment circuit includes an NPN-type transistor b, the C pole of the transistor a is connected to the B pole of the transistor b, and the E pole of the transistor a is connected to the C pole of the transistor b, and the lower level of the E pole of the transistor a can be recognized as a low level by the MCU signal circuit.

2. The short-circuit protection circuit according to claim 1, characterized in that: The short-circuit judgment circuit further includes a resistor R1 and a capacitor C1 connected in parallel, which are used for filtering and adjusting the response time of the short-circuit protection.

3. The short-circuit protection circuit according to any one of claims 1 to 2, characterized in that: The short-circuit processing circuit includes a short-circuit processing module a, a short-circuit processing module b and a short-circuit processing module c. The short-circuit processing module b is connected to the half-bridge pre-driver chip a, and the short-circuit processing module c is connected to the half-bridge pre-driver chip b. The short-circuit processing module a is simultaneously connected to the short-circuit processing module b and the short-circuit processing module c to simultaneously control the half-bridge pre-driver chip a and the half-bridge pre-driver chip b.

4. The short-circuit protection circuit according to claim 3, characterized in that: The short-circuit processing module a includes a transistor Qa, the short-circuit processing module b includes a transistor Qb, and the short-circuit processing module c includes a transistor Qc. The transistor Qa is a PNP type, and the transistor Qb and the transistor Qc are NPN types. The C pole of the transistor Qa is connected to the B pole of the transistor Qb and the transistor Qc, and the C pole of the transistor Qb and the C pole of the transistor Qc are connected to the MCU signal circuit, so that the PWM signal emitted by the MCU signal circuit is maintained at a low level in the event of a short circuit.

5. The short-circuit protection circuit according to any one of claims 1 to 2, characterized in that: The short-circuit processing circuit connects the PWM signal sent by the MCU signal circuit to the short-circuit judgment circuit to maintain the PWM signal sent by the MCU signal circuit at a low level when a short circuit occurs.

6. The short-circuit protection circuit according to claim 5, characterized in that: The short-circuit processing circuit includes a diode Da and a diode Db, the positive pole of the diode Da is connected to the MCU signal circuit and the half-bridge pre-driver chip a, the positive pole of the diode Db is connected to the MCU signal circuit and the half-bridge pre-driver chip b, and the negative poles of the diode Da and the diode Db are connected to the short-circuit judgment circuit.

7. The short-circuit protection circuit according to any one of claims 1 to 2, characterized in that: The short-circuit processing circuit includes an input power supply VCCA and an output power supply VCCB. The short-circuit processing circuit connects the output power supply VCCB to the half-bridge pre-driver circuit and supplies power to it, so as to cut off the output power supply VCCB in the event of a short circuit, causing the half-bridge pre-driver circuit to lose power supply and enter low-voltage protection.

8. The short-circuit protection circuit according to claim 7, characterized in that: The short-circuit processing circuit includes an NPN-type transistor Ma and a PNP-type transistor Mb, the B pole of the transistor Ma is connected to the short-circuit judgment circuit, the C pole of the transistor Ma is connected to the B pole of the transistor Mb, the input power supply VCCA is connected to the E pole of the transistor Mb, and the C pole of the transistor Mb outputs the output power supply VCCB.

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