Short circuit protection circuit, switching tube control device and power supply system

Abstract

The utility model discloses a short circuit protection circuit, switch tube controlling means and power supply system, wherein, short circuit protection circuit includes: current sampling unit is suitable for connecting switch tube, and current sampling unit is used for sampling the load current that flows through switch tube, drive unit is connected with the output end of current sampling unit, and is suitable for connecting switch tube's control end, wherein, under the condition that load current shows that there is short circuit in the power channel, drive unit closes switch tube, isolation unit is connected with the current feedback end of drive unit, and the output end of isolation unit is suitable for connecting the filter circuit of control unit, and isolation unit is used for isolating drive unit and filter circuit. The circuit guarantees that drive unit can close switch tube in time when the power channel takes place short circuit.

Description

Technical Field

[0001] This application relates to the field of protection circuit technology, and in particular to a short-circuit protection circuit, a switching transistor control device, and a power supply system. Background Technology

[0002] In current intelligent power distribution products, driver chips are typically used for intelligent protection and status monitoring of power consumption channels. However, the current feedback function and short-circuit protection function of the driver chip share the same chip pin. When a short circuit occurs in the power consumption channel, the short-circuit protection comparator circuit within the driver chip is affected by the filtering circuit of the current feedback pin, resulting in a delay in short-circuit protection time. Due to the delay in short-circuit protection, the peak transient current of the power consumption channel increases. When the peak transient current exceeds the maximum current withstand capability of the switching devices in the power consumption channel, it will cause the switching devices to fail due to overcurrent. Utility Model Content

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to provide a short-circuit protection circuit. By adding an isolation unit between the current output terminal of the drive unit and the filter circuit, the short-circuit protection function of the drive unit is not affected by the filter circuit, thereby ensuring that the drive unit can promptly shut off the switching transistor when a short circuit occurs in the power supply channel, thus preventing damage to the switching transistor.

[0004] The second objective of this invention is to provide a switching transistor control device.

[0005] The third objective of this invention is to provide a power supply system.

[0006] To achieve the above objectives, a short-circuit protection circuit is proposed according to a first aspect embodiment of the present invention, comprising: a current sampling unit, the input terminal of which is adapted to be connected to a switching transistor, the current sampling unit being used to sample the load current flowing through the switching transistor; a driving unit, the input terminal of which is connected to the output terminal of the current sampling unit, the output terminal of which is adapted to be connected to the control terminal of the switching transistor, wherein, when a short circuit exists in the power supply channel indicated by the load current, the driving unit turns off the switching transistor; and an isolation unit, the input terminal of which is connected to the current feedback terminal of the driving unit, the output terminal of which is adapted to be connected to the filter circuit of the control unit, the isolation unit being used to isolate the driving unit and the filter circuit.

[0007] The short-circuit protection circuit according to an embodiment of the present invention includes a current sampling unit, a driving unit, and an isolation unit. The input terminal of the isolation unit is connected to the current feedback terminal of the driving unit, and the output terminal of the isolation unit is adapted to connect to the filter circuit of the control unit. The isolation unit is disposed between the current output terminal of the driving unit and the filter circuit to isolate the short-circuit protection circuit in the driving unit from the filter circuit, so that the short-circuit protection function of the driving unit is not affected by the filter circuit, thereby ensuring that the driving unit can turn off the switching transistor in time when a short circuit occurs in the power channel, thereby avoiding damage to the switching transistor.

[0008] According to one embodiment of the present invention, the isolation unit includes: a first operational amplifier, the positive input terminal of the first operational amplifier being connected to the current feedback terminal of the driving unit, the output terminal of the first operational amplifier being connected to the negative input terminal of the first operational amplifier, and is suitable for connecting a filter circuit.

[0009] In the above embodiment, the isolation unit uses a voltage follower to isolate the driving unit and the filter circuit. The high input impedance of the voltage follower makes it almost an open circuit to the driving unit of the previous stage, ensuring the independence of the previous stage circuit. At the same time, the low output impedance of the voltage follower makes it equivalent to a constant voltage source, and the output voltage is not affected by the impedance change of the subsequent stage circuit, thereby ensuring the sampling accuracy of the subsequent stage circuit.

[0010] According to one embodiment of the present invention, the driving unit includes: an amplification module, the input terminal of which is connected to a current sampling unit, and the first output terminal of which is connected to the input terminal of an isolation unit; the amplification module is used to amplify the sampled value output by the current sampling unit; a control module, the output terminal of which is adapted to connect to the control terminal of a switching transistor; and a comparison module, the positive input terminal of which is connected to the first output terminal of the amplification module, the negative input terminal of which is adapted to input a short-circuit protection voltage, and the output terminal of which is connected to the input terminal of the control module; the comparison module is used to compare the amplified sampled value with the short-circuit protection voltage, wherein, if the amplified sampled value is greater than the short-circuit protection voltage, the comparison module triggers the control module to turn off the switching transistor.

[0011] In the above embodiment, since the isolation unit isolates the comparison module and the filter circuit, the comparison module will quickly compare and output the comparison result to control the module. In this way, the control module can turn off the switching transistor in time when the power channel is short-circuited.

[0012] According to one embodiment of the present invention, the short-circuit protection circuit further includes a voltage configuration unit connected to the amplification module. The voltage configuration unit is used to configure the short-circuit protection voltage. The second output terminal of the amplification module is also connected to the negative input terminal of the comparison module. The amplification module is used to provide the configured short-circuit protection voltage to the comparison module.

[0013] In the above embodiment, the voltage configuration unit is connected to the amplification module. By adjusting the short-circuit protection voltage output from the second output terminal of the amplification module, the short-circuit protection voltage can be flexibly adjusted, thereby improving the accuracy of short-circuit protection.

[0014] According to one embodiment of the present invention, the voltage configuration unit includes: a first resistor, one end of which is connected to the first input terminal of the amplification module, and the other end of which is connected to one end of the current sampling unit; a second resistor, one end of which is connected to the second input terminal of the amplification module, and the other end of which is connected to the other end of the current sampling unit; and a third resistor, one end of which is connected to the input terminal of the isolation unit and the first output terminal of the amplification module, and the other end of which is grounded.

[0015] In the above embodiments, the short-circuit protection voltage can be adjusted by adjusting the resistance values ​​of the first resistor, the second resistor, and the third resistor.

[0016] According to one embodiment of the present invention, the amplification module includes: a second operational amplifier, the positive input terminal of the second operational amplifier being connected to one end of a first resistor, the negative input terminal of the second operational amplifier being connected to one end of a second resistor, and the output terminal of the second operational amplifier being connected to the negative input terminal of a comparator module; a first switching transistor, the first terminal of the first switching transistor being connected to the positive input terminal of the second operational amplifier, the second terminal of the first switching transistor being connected to the positive input terminal of the comparator module, one end of a third resistor, and the input terminal of an isolation unit, respectively, and the control terminal of the first switching transistor being connected to the output terminal of the second operational amplifier.

[0017] In the above embodiments, since the first resistor, the second resistor, and the third resistor can adjust the amplitude of the amplified sampled value and the voltage output by the second operational amplifier, the short-circuit protection voltage can be adjusted by adjusting the first resistor, the second resistor, and the third resistor.

[0018] According to one embodiment of the present invention, the driving unit further includes: a current direction detection module, the input terminal of which is connected to the current sampling unit, and the output terminal of which is adapted to be connected to the control unit. The current direction detection module is used to detect the current direction of the load current and provide the current direction to the control unit.

[0019] In the above embodiments, the drive unit is also provided with a current direction detection module, which can feed back the current flow direction to the control unit. In this way, the control unit can perform fault monitoring based on the current flow direction and the sampled value output by the current feedback terminal.

[0020] According to one embodiment of the present invention, the current sampling unit includes a sampling resistor, which is adapted to be connected in series with the switching transistor.

[0021] In the above embodiment, the load current flows through the sampling resistor, which generates a small voltage across the sampling resistor. The current is then monitored in real time based on the voltage across the sampling resistor.

[0022] To achieve the above objectives, a switching transistor control device is provided according to a second aspect of the present invention, comprising: at least one short-circuit protection circuit according to any of the preceding embodiments, each short-circuit protection circuit being adapted to connect to a switching transistor, each short-circuit protection circuit being used to sample the load current flowing through the corresponding switching transistor and to provide short-circuit protection for the corresponding switching transistor; at least one filter circuit, the input terminal of each filter circuit being connected to the output terminal of a short-circuit protection circuit, each filter circuit being used to filter the current sample value output by the corresponding short-circuit protection circuit; and a control unit, the control unit being connected to the output terminal of each filter circuit, the control unit being used to determine the load current based on each filtered current sample value.

[0023] According to the present invention, the switching transistor control device adopts the above-mentioned short-circuit protection circuit and adds an isolation unit between the current output terminal of the drive unit and the filter circuit, so that the short-circuit protection function of the drive unit is not affected by the filter circuit, ensuring that the drive unit can turn off the switching transistor in time when a short circuit occurs in the power channel, thereby improving the safety of the switching transistor control device and avoiding damage to the switching transistor.

[0024] According to one embodiment of the present invention, each filter circuit includes: a fourth resistor, one end of which is connected to the output terminal of the short-circuit protection circuit, and the other end of which is connected to the control unit; and a first capacitor, one end of which is connected to the other end of the fourth resistor and the control unit, and the other end of which is grounded.

[0025] In the above embodiments, by using a low-pass filter circuit composed of a fourth resistor and a first capacitor, high-frequency noise in the current sampling value can be effectively filtered out, thereby improving the sampling accuracy of the control unit.

[0026] To achieve the above objectives, a power supply system is provided according to a third aspect of the present invention, comprising: at least one switching transistor, the at least one switching transistor being adapted to provide power to a load; and a switching transistor control device of any of the preceding embodiments, the switching transistor control device being connected to the control terminal of each switching transistor, the switching transistor control device being used to control each switching transistor to provide power to the load.

[0027] According to the power supply system of this utility model embodiment, by adopting the above-mentioned switching transistor control device, an isolation unit is added between the current output terminal of the drive unit and the filter circuit, ensuring that the drive unit can turn off the switching transistor in time when a short circuit occurs in the power consumption channel, thereby avoiding damage to the switching transistor and improving the safety and reliability of the power supply system.

[0028] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] Figure 1 This is a circuit diagram of a short-circuit protection circuit according to an embodiment of the present invention; Figure 2 This is a circuit diagram of an isolation unit according to an embodiment of the present invention; Figure 3 This is a circuit diagram of a current sampling unit according to an embodiment of the present invention; Figure 4 This is a circuit diagram of a driving unit according to an embodiment of the present invention; Figure 5 This is a circuit diagram of a voltage configuration unit according to an embodiment of the present invention; Figure 6 This is a circuit diagram of a current detection module according to an embodiment of the present invention; Figure 7 This is a circuit diagram of a filter circuit according to an embodiment of the present invention; Figure 8 This is a circuit diagram of a power supply system according to an embodiment of the present invention. Detailed Implementation

[0030] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0031] The following description, with reference to the accompanying drawings, describes an embodiment of the present invention, including a short-circuit protection circuit, a switching transistor control device, and a power supply system.

[0032] Figure 1 This is a circuit diagram of a short-circuit protection circuit according to an embodiment of the present invention. Figure 1 As shown, the short-circuit protection circuit 100 includes: a current sampling unit 10, a driving unit 20, and an isolation unit 30.

[0033] The input terminal of the current sampling unit 10 is adapted to be connected to the switching transistor Q, and the current sampling unit 10 is used to sample the load current flowing through the switching transistor Q; the input terminal of the drive unit 20 is connected to the output terminal of the current sampling unit 10, and the output terminal of the drive unit 20 is adapted to be connected to the control terminal of the switching transistor Q, wherein, in the case of a short circuit in the power supply channel represented by the load current, the drive unit 20 turns off the switching transistor Q; the input terminal of the isolation unit 30 is connected to the current feedback terminal of the drive unit 20, and the output terminal of the isolation unit 30 is adapted to be connected to the filter circuit 200 of the control unit 300, and the isolation unit 30 is used to isolate the drive unit 20 and the filter circuit 200.

[0034] Specifically, the current sampling unit 10 samples the load current flowing through the switching transistor Q. The drive unit 20 performs short-circuit protection based on the load current sampling value output by the current sampling unit 10. The load current sampling value output by the current sampling unit 10 is positively correlated with the load current. When a short-circuit fault occurs in the power channel where the switching transistor Q is located, the load current increases, and the load current sampling value output by the current sampling unit 10 also increases. Therefore, the load current sampling value can be used to determine whether a short-circuit fault has occurred in the power channel. When a short-circuit fault occurs in the power channel, the drive unit 20 turns off the switching transistor Q to prevent damage to the switching transistor Q; when the power channel is operating normally, the current state of the switching transistor Q remains unchanged. The current feedback terminal of the drive unit 20 is also used to feed back the sampling value to the control unit 300. The control unit 300 determines the load current based on the sampling value and performs fault diagnosis based on the load current. To improve the sampling accuracy of the control unit 300, a filter circuit 200 is set between the control unit 300 and the drive unit 20 to filter the sampled values. However, the filter circuit 200 affects the amplitude of the sampled values, thus delaying the short-circuit protection function of the drive unit 20 and preventing timely shutdown control of the switching transistor Q. In this embodiment, an isolation unit 30 is added between the filter circuit 200 and the current output terminal of the drive unit 20. The isolation unit 30 isolates the drive unit 20 from the filter circuit 200. Therefore, the drive unit 20 is not affected by the filter circuit 200 when performing short-circuit protection, and can promptly shut down the switching transistor Q when a short-circuit fault occurs in the power supply channel. Furthermore, the isolation unit 30 can also provide the sampled values ​​to the filter circuit 200 without affecting the sampling operation of the control unit 300.

[0035] It should be noted that the switching transistor Q can be a MOS (Metal Oxide Semiconductor) transistor, and the control unit 300 can be an MCU (Microcontroller Unit).

[0036] In the above embodiments, the isolation unit is disposed between the current output terminal of the drive unit and the filter circuit to isolate the short-circuit protection circuit in the drive unit from the filter circuit, so that the short-circuit protection function of the drive unit is not affected by the filter circuit, thereby ensuring that the drive unit can turn off the switching transistor in time when a short circuit occurs in the power channel, thereby avoiding damage to the switching transistor.

[0037] In some embodiments, such as Figure 2 As shown, the isolation unit 30 includes: a first operational amplifier OP1, the positive input terminal of the first operational amplifier OP1 is connected to the current feedback terminal of the driving unit 20, the output terminal of the first operational amplifier OP1 is connected to the negative input terminal of the first operational amplifier OP1, and is suitable for connecting to the filter circuit 200.

[0038] In other words, the first operational amplifier OP1 forms a voltage follower. The isolation unit 30 uses the voltage follower to isolate the current output terminal of the drive unit 20 from the filter circuit 200. The high input impedance of the voltage follower makes it almost an open circuit to the drive unit 20 in the previous stage, ensuring the independence of the previous stage circuit. At the same time, the low output impedance of the voltage follower makes it equivalent to a constant voltage source, and the output voltage is not affected by the impedance change of the subsequent stage circuit, thus ensuring the sampling accuracy of the subsequent stage circuit.

[0039] In some embodiments, such as Figure 3 As shown, the current sampling unit 10 includes a sampling resistor Rs, which is adapted to be connected in series with the switching transistor Q.

[0040] Specifically, the sampling resistor Rs is connected in series with the switching transistor Q. When the load current flows through the sampling resistor Rs, a small voltage is generated across it. The sampled value output by the current sampling unit 10 is the voltage across the sampling resistor Rs. A high-precision sampling resistor Rs can be used to further improve the accuracy of current sampling.

[0041] In some embodiments, such as Figure 4As shown, the driving unit 20 includes an amplification module 21, a control module 22, and a comparison module 23. The input terminal of the amplification module 21 is connected to the current sampling unit 10, and the first output terminal of the amplification module 21 is connected to the input terminal of the isolation unit 30. The amplification module 21 is used to amplify the sampled value output by the current sampling unit 10. The output terminal of the control module 22 is adapted to connect to the control terminal of the switching transistor Q. The positive input terminal of the comparison module 23 is connected to the first output terminal of the amplification module 21, the negative input terminal of the comparison module 23 is adapted to input the short-circuit protection voltage, and the output terminal of the comparison module 23 is connected to the input terminal of the control module 22. The comparison module 23 is used to compare the amplified sampled value with the short-circuit protection voltage. If the amplified sampled value is greater than the short-circuit protection voltage, the comparison module 23 triggers the control module 22 to turn off the switching transistor Q.

[0042] Specifically, when the power supply channel is operating normally, the load current is relatively small, so the sampled value obtained by the current sampling unit 10 is also relatively small. The sampled value needs to be amplified by the amplification module 21. Then, the amplified sampled value is provided to the isolation unit 30 and the comparison module 23 respectively. The comparison module 23 compares the amplified sampled value with the short-circuit protection voltage. When the amplified sampled value is greater than the short-circuit protection voltage, the control module 22 is triggered to enter the safety mode. In the safety mode, the control module 22 will turn off the switching transistor Q.

[0043] In an optional implementation, the control module 22 is also adapted to be connected to the control unit 300. The control module 22 is also used to send a fault signal to the control unit 300 after the control switch Q is turned off, so that the control unit 300 can determine that a short circuit fault has occurred in the power supply channel based on the fault signal.

[0044] For example, such as Figure 5 As shown, the comparison module 23 includes a third operational amplifier OP3. The positive input terminal of the third operational amplifier OP3 is the positive input terminal of the comparison module 23, the negative input terminal of the third operational amplifier OP3 is the negative input terminal of the comparison module 23, and the output terminal of the third operational amplifier OP3 is the output terminal of the comparison module 23. When the amplified sampled value is less than or equal to the preset short-circuit voltage, the third operational amplifier OP3 outputs a low-level signal; when the amplified sampled value is greater than the short-circuit protection voltage, the third operational amplifier OP3 outputs a high-level signal. Upon receiving the aforementioned high-level signal, the control module 22 enters a safety mode.

[0045] In this embodiment, because the isolation unit isolates the comparison module and the filter circuit, the comparison module can quickly perform comparisons and output the comparison result to control the control module. This allows the control module to promptly turn off the switching transistor when a short circuit occurs in the power supply channel, improving the entire short-circuit protection process to within 10 microseconds. If the isolation unit were absent, the input of the comparison module would be affected by the filter circuit, leading to a longer current rise time. The comparison module would output a slower result, and the exponentially increasing short-circuit current would quickly exceed the switching transistor's current limit, causing it to burn out due to overcurrent.

[0046] In some embodiments, such as Figure 5 As shown, the short-circuit protection circuit 100 also includes a voltage configuration unit 40, which is connected to the amplification module 21. The voltage configuration unit 40 is used to configure the short-circuit protection voltage. The second output terminal of the amplification module 21 is also connected to the negative input terminal of the comparison module 23. The amplification module 21 is used to provide the configured short-circuit protection voltage to the comparison module 23.

[0047] In other words, the amplification module 21 can also be used to provide short-circuit protection voltage to the comparison module 23. The voltage configuration unit 40 is connected to the amplification module 21. By adjusting the short-circuit protection voltage output from the second output terminal of the amplification module 21, the short-circuit protection voltage can be flexibly adjusted, thereby improving the accuracy of short-circuit protection.

[0048] In some embodiments, such as Figure 5 As shown, the voltage configuration unit 40 includes a first resistor R1, a second resistor R2, and a third resistor R3. One end of the first resistor R1 is connected to the first input terminal of the amplification module 21, and the other end of the first resistor R1 is connected to one end of the current sampling unit 10. One end of the second resistor R2 is connected to the second input terminal of the amplification module 21, and the other end of the second resistor R2 is connected to the other end of the current sampling unit 10. One end of the third resistor R3 is connected to the input terminal of the isolation unit 30 and the first output terminal of the amplification module 21, and the other end of the third resistor R3 is grounded.

[0049] Specifically, when the current sampling unit 10 uses a sampling resistor Rs for sampling, the output voltage of the sampled value from the current sampling unit 10 is a differential voltage signal. The first resistor R1 and the second resistor R2 are differential input matching resistors. By adjusting the first resistor R1 and the second resistor R2, the amplification degree of the sampled value by the amplification module 21 can be adjusted. The third resistor R3 is set between the first output terminal of the amplification module 21 and the input terminal of the isolation unit 30, and can adjust the amplified sampled value output by the amplification module 21. Therefore, the short-circuit protection voltage can be adjusted by using the first resistor R1, the second resistor R2, and the third resistor R3.

[0050] In some embodiments, such as Figure 5 As shown, the amplification module 21 includes: a second operational amplifier OP2 and a first switching transistor Q1, wherein the positive input terminal of the second operational amplifier OP2 is connected to one end of the first resistor R1, the negative input terminal of the second operational amplifier OP2 is connected to one end of the second resistor R2, and the output terminal of the second operational amplifier OP2 is connected to the negative input terminal of the comparator module 23; the first terminal of the first switching transistor Q1 is connected to the positive input terminal of the second operational amplifier OP2, the second terminal of the first switching transistor Q1 is connected to the positive input terminal of the comparator module 23, one end of the third resistor R3, and the input terminal of the isolation unit 30, respectively, and the control terminal of the first switching transistor Q1 is connected to the output terminal of the second operational amplifier OP2.

[0051] Specifically, since the sampled value output by the current sampling unit 10 is a differential voltage signal, the second operational amplifier OP2 is a differential amplifier. The positive input terminal of the second operational amplifier OP2 is connected to one end of the current sampling unit 10 through the first resistor R1, and the negative input terminal of the second operational amplifier OP2 is connected to the other end of the current sampling unit 10 through the second resistor R2. The output terminal of the second operational amplifier OP2 is used to output a short-circuit protection voltage. The first resistor R1 and the second resistor R2 can adjust the amplification level of the second operational amplifier OP2 to adjust the amplitude of the short-circuit protection voltage output by the second operational amplifier OP2. When the voltage output by the second operational amplifier OP2 is greater than the turn-on voltage of the first switching transistor Q1, the first switching transistor Q1 is turned on, and one end of the sampling resistor Rs, the first resistor R1, and the third resistor R3 form a circuit. The first resistor R1 and the third resistor R3 divide the voltage at one end of the sampling resistor Rs. Therefore, by adjusting the resistance values ​​of the first resistor R1 and the third resistor R3, the amplitude of the amplified sampled value can be changed. The first switching transistor Q1 can also be a MOSFET.

[0052] In the above embodiments, since the first resistor, the second resistor, and the third resistor can adjust the amplitude of the amplified sampled value and the voltage output by the second operational amplifier, the short-circuit protection voltage can be adjusted by adjusting the first resistor, the second resistor, and the third resistor.

[0053] In some embodiments, such as Figure 6 As shown, the drive unit 20 also includes a current direction detection module 24. The input terminal of the current direction detection module 24 is connected to the current sampling unit 10, and the output terminal of the current direction detection module 24 is adapted to be connected to the control unit 300. The current direction detection module 24 is used to detect the current direction of the load current and provide the current direction to the control unit 300.

[0054] Understandably, the drive unit 20 also includes a current direction detection module 24. This module detects the direction of current flowing through the current sampling unit 10 based on the sampled values ​​output by the current sampling unit 10. The drive unit 20 also has a diagnostic pin connected to the control unit 300. The current direction detection module feeds back the current direction to the control unit 300 via the diagnostic pin, allowing the control unit 300 to perform fault monitoring based on the current direction and the sampled values ​​output from the current feedback terminal.

[0055] Optional, such as Figure 6 As shown, the current direction detection module 24 includes a fourth operational amplifier OP4. The positive input terminal of the fourth operational amplifier OP4 is connected to one end of the current sampling unit 10, and the negative input terminal of the fourth operational amplifier OP4 is connected to the other end of the current sampling unit 10. When the fourth operational amplifier OP4 outputs a high-level signal, the current flows from one end of the current sampling unit 10 to the other end; when the fourth operational amplifier OP4 outputs a low-level signal, the current flows from the other end of the current sampling unit 10 to one end.

[0056] It should be noted that when the short-circuit protection circuit 100 includes the first resistor R1 and the second resistor R2, the positive input terminal of the fourth operational amplifier OP4 is connected to one end of the first resistor R1, and the negative input terminal of the fourth operational amplifier OP4 is connected to one end of the second resistor R2.

[0057] The technical solution of this application is further described in detail below with reference to specific implementation methods: When adopting such Figure 6 When the short-circuit protection circuit shown is used, the short-circuit protection circuit 100 operates as follows: Assuming the power supply channel is operating normally, the load current flows through the sampling resistor Rs, generating a small voltage across it to obtain a sample value. This sample value is then input to the second operational amplifier OP2 via the first resistor R1 and the second resistor R2. The second operational amplifier OP2 performs differential amplification and then sends the amplified sample value to the filter circuit 200 via the current output terminal of the drive unit 20 and the first operational amplifier OP1. After filtering by the filter circuit 200, the sample value is input to the sampling port of the control unit 300 for processing. The control unit 300 calculates the actual current magnitude based on the filtered sample value and monitors and diagnoses the actual current. Simultaneously, the amplified sample value is input to the comparison module 23, which compares it with the short-circuit protection voltage. Because the power supply channel is operating normally, the amplified sample value is less than or equal to the short-circuit protection voltage, and the control module 22 will not turn off the switching transistor Q. The sample value is also input to the fourth operational amplifier OP4 via the first resistor R1 and the second resistor R2 to detect the current flow direction through the sampling resistor Rs.

[0058] Assuming a short circuit fault occurs in the power supply channel, the voltage across the sampling resistor Rs will increase sharply, meaning the sampled value will increase sharply. The sampled value is input to the second operational amplifier OP2 through the first resistor R1 and the second resistor R2. The second operational amplifier OP2 performs differential amplification, and then inputs the amplified sampled value to the comparison module 23. Since the amplified sampled value is greater than the short circuit protection voltage, the comparison module 23 triggers the control module 22 to turn off the switching transistor Q and outputs a fault signal to the control unit 300. The entire short circuit protection process will be completed within 10 microseconds.

[0059] In summary, according to the short-circuit protection circuit of this utility model embodiment, the isolation unit is disposed between the current output terminal of the driving unit and the filter circuit to isolate the short-circuit protection circuit in the driving unit from the filter circuit. This ensures that the short-circuit protection function of the driving unit is not affected by the filter circuit, thereby guaranteeing that the driving unit can promptly turn off the switching transistor when a short circuit occurs in the power supply channel, thus preventing damage to the switching transistor. Furthermore, the isolation unit uses a voltage follower for isolation. The high input impedance of the voltage follower makes it almost an open circuit to the preceding driving unit, ensuring the independence of the preceding circuit. Simultaneously, the low output impedance of the voltage follower makes it equivalent to a constant voltage source, and the output voltage is unaffected by changes in the impedance of the subsequent circuit, thereby ensuring the sampling accuracy of the subsequent circuit.

[0060] Corresponding to the above embodiments, this utility model also proposes a switching transistor control device. For example... Figure 1As shown, the switching transistor control device includes: at least one short-circuit protection circuit 100 of any of the foregoing embodiments, at least one filter circuit 200, and a control unit 300. Each short-circuit protection circuit 100 is adapted to be connected to a switching transistor Q. Each short-circuit protection circuit 100 is used to sample the load current flowing through the corresponding switching transistor Q and to provide short-circuit protection for the corresponding switching transistor Q. The input terminal of each filter circuit 200 is connected to the output terminal of a short-circuit protection circuit 100. The filter circuit 200 is used to filter the current sample value output by the corresponding short-circuit protection circuit. The control unit 300 is connected to the output terminal of each filter circuit 200. The control unit 300 is used to determine the load current based on each filtered current sample value.

[0061] In the above embodiments, by adopting the short-circuit protection circuit described above, an isolation unit is added between the current output terminal of the drive unit and the filter circuit, so that the short-circuit protection function of the drive unit is not affected by the filter circuit, ensuring that the drive unit can turn off the switching transistor in time when a short circuit occurs in the power channel, thereby improving the safety of the switching transistor control device and avoiding damage to the switching transistor.

[0062] In some embodiments, such as Figure 7 As shown, each filter circuit 200 includes: a fourth resistor R4 and a first capacitor C1, wherein one end of the fourth resistor R4 is connected to the output terminal of the short-circuit protection circuit 100, and the other end of the fourth resistor R4 is connected to the control unit 300; one end of the first capacitor C1 is connected to the other end of the fourth resistor R4 and the control unit 300, and the other end of the first capacitor C1 is grounded.

[0063] In other words, the filter circuit 200 in this embodiment is a low-pass filter circuit 200, which can effectively filter out high-frequency noise in the current sampling value through the fourth resistor R4 and the first capacitor C1, thereby improving the sampling accuracy of the control unit 300.

[0064] Corresponding to the above embodiments, this utility model also proposes a power supply system. For example... Figure 8 As shown, the power supply system includes: at least one switch Q and a switch control device 1000 of any of the foregoing embodiments, wherein at least one switch Q is adapted to provide power to the load 400; the switch control device 1000 is connected to the control terminal of each switch Q, and the switch control device 1000 is used to control each switch Q to provide power to the load 400.

[0065] It should be noted that the number of switching transistors Q is not limited to... Figure 8 The single switch shown can also be multiple switches Q, which can be connected in series; specific connections are not limited here. The connection method between the switch control device 1000 and the switches Q and the load 400 is also not limited. Figure 8 The connection method shown can also be used to set the switch control device 1000 in other locations. For example, the switch control device 1000 can be set between the first end of the switch Q and the power supply, and the second end of the switch Q can be adapted to connect to the load 400, or the second end of the switch Q can be connected to one end of the load 400, and the switch control device 1000 can be connected to the other end of the load 400. The configuration can be made according to the actual situation.

[0066] According to the power supply system of this utility model embodiment, by adopting the above-mentioned switching transistor control device, an isolation unit is added between the current output terminal of the drive unit and the filter circuit, ensuring that the drive unit can turn off the switching transistor in time when a short circuit occurs in the power consumption channel, thereby avoiding damage to the switching transistor and improving the safety and reliability of the power supply system.

[0067] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0068] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0069] Furthermore, the terms "first," "second," etc., used in the embodiments of this utility model are for descriptive purposes only and should not be construed as indicating or implying relative importance, or implicitly specifying the number of technical features indicated in this embodiment. Therefore, features defined with terms such as "first" and "second" in the embodiments of this utility model can explicitly or implicitly indicate that the embodiment includes at least one of those features. In the description of this utility model, the word "multiple" means at least two or more, such as two, three, four, etc., unless otherwise explicitly specified in the embodiments.

[0070] In this utility model, unless otherwise explicitly specified or limited in the embodiments, the terms "installation," "connection," "joining," and "fixing" appearing in the embodiments should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral part; it can also be a mechanical connection, an electrical connection, etc. Of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two components, or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific implementation.

[0071] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0072] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A short-circuit protection circuit, characterized in that, include: A current sampling unit, wherein the input terminal of the current sampling unit is adapted to be connected to a switching transistor, and the current sampling unit is used to sample the load current flowing through the switching transistor; A driving unit, wherein the input terminal of the driving unit is connected to the output terminal of the current sampling unit, and the output terminal of the driving unit is adapted to be connected to the control terminal of the switching transistor, wherein the driving unit turns off the switching transistor when the load current indicates that there is a short circuit in the power consumption channel; An isolation unit is provided, wherein the input terminal of the isolation unit is connected to the current feedback terminal of the drive unit, and the output terminal of the isolation unit is adapted to be connected to a filter circuit. The isolation unit is used to isolate the drive unit and the filter circuit.

2. The short-circuit protection circuit according to claim 1, characterized in that, The isolation unit includes: a first operational amplifier, the positive input terminal of the first operational amplifier being connected to the current feedback terminal of the driving unit, the output terminal of the first operational amplifier being connected to the negative input terminal of the first operational amplifier, and is adapted to connect to the filter circuit.

3. The short-circuit protection circuit according to claim 1, characterized in that, The driving unit includes: An amplification module is provided, wherein the input terminal of the amplification module is connected to the current sampling unit, and the first output terminal of the amplification module is connected to the input terminal of the isolation unit. The amplification module is used to amplify the sampled value output by the current sampling unit. Control module, wherein the output terminal of the control module is adapted to be connected to the control terminal of the switching transistor; The comparison module has its positive input connected to the first output of the amplification module, its negative input adapted to receive a short-circuit protection voltage, and its output connected to the control module. The comparison module is used to compare the amplified sampled value with the short-circuit protection voltage. If the amplified sampled value is greater than the short-circuit protection voltage, the comparison module triggers the control module to turn off the switching transistor.

4. The short-circuit protection circuit according to claim 3, characterized in that, The short-circuit protection circuit further includes a voltage configuration unit connected to the amplification module. The voltage configuration unit is used to configure the short-circuit protection voltage. The second output terminal of the amplification module is also connected to the negative input terminal of the comparison module. The amplification module is also used to provide the configured short-circuit protection voltage to the comparison module.

5. The short-circuit protection circuit according to claim 4, characterized in that, The voltage configuration unit includes: A first resistor, one end of which is connected to the first input terminal of the amplification module, and the other end of which is connected to one end of the current sampling unit; The second resistor has one end connected to the second input terminal of the amplification module and the other end connected to the other end of the current sampling unit. The third resistor has one end connected to the input terminal of the isolation unit and the first output terminal of the amplification module, and the other end grounded.

6. The short-circuit protection circuit according to claim 5, characterized in that, The amplification module includes: The second operational amplifier has its positive input terminal connected to one end of the first resistor, its negative input terminal connected to one end of the second resistor, and its output terminal connected to the negative input terminal of the comparison module. The first switch transistor has its first terminal connected to the positive input terminal of the second operational amplifier, its second terminal connected to the positive input terminal of the comparator module, one end of the third resistor, and the input terminal of the isolation unit, respectively, and its control terminal connected to the output terminal of the second operational amplifier.

7. The short-circuit protection circuit according to claim 3, characterized in that, The driving unit further includes a current direction detection module, the input terminal of which is connected to the current sampling unit, and the output terminal of which is adapted to be connected to the control unit. The current direction detection module is used to detect the current direction of the load current and provide the current direction to the control unit.

8. The short-circuit protection circuit according to any one of claims 1-7, characterized in that, The current sampling unit includes a sampling resistor, which is adapted to be connected in series with the switching transistor.

9. A switching transistor control device, characterized in that, include: At least one short-circuit protection circuit according to any one of claims 1-8, each short-circuit protection circuit being adapted to connect to a switching transistor, each short-circuit protection circuit being used to sample the load current flowing through the corresponding switching transistor and to provide short-circuit protection for the corresponding switching transistor; The filter circuit has its input terminal connected to the output terminal of a short-circuit protection circuit. Each filter circuit is used to filter the current sampling value output by the corresponding short-circuit protection circuit. A control unit is connected to the output of each filter circuit, and the control unit is used to determine the load current based on each filtered current sample value.

10. The switching transistor control device according to claim 9, characterized in that, Each filter circuit includes: The fourth resistor has one end connected to the output terminal of the corresponding short-circuit protection circuit and the other end connected to the control unit. A first capacitor, one end of which is connected to the other end of the fourth resistor and the control unit, and the other end of the first capacitor is grounded.

11. A power supply system, characterized in that, include: At least one switching transistor, said at least one switching transistor being adapted to provide power to a load; According to claim 9 or 10, the switching transistor control device is connected to the control terminal of each switching transistor, and the switching transistor control device is used to control each switching transistor to provide the power supply to the load.

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