Fault protection circuit and battery management system

Abstract

The utility model provides a fault protection circuit. The fault protection circuit comprises an output sampling circuit, a short circuit detection circuit, an overcurrent detection circuit, a current limiting control circuit, an input control circuit and a microcontroller. The output sampling circuit samples the current of the power supply output module through a first electronic switching tube and a first sampling resistor. The short circuit detection circuit and the over-current detection circuit are respectively used for detecting short circuit and over-current faults and are connected with the microcontroller to realize transmission and processing of fault signals. The input control circuit controls on and off of the first electronic switching tube so as to control power output. When the circuit detects short circuit and overcurrent faults at the same time, power supply output can be cut off in an extremely short time, and the current-limiting control circuit can rapidly reduce the control end voltage of the first electronic switching tube, so that the damage of components caused by overlarge current is avoided, heat generation is reduced, and the safety of the circuit is further improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of battery management systems, in particular to a fault protection circuit and a battery management system. BACKGROUND

[0002] In power electronic circuit systems, short circuit and overcurrent are two common and extremely destructive faults. Short circuit refers to the accidental conduction of two points of different potentials in the circuit, resulting in abnormal increase of current; while overcurrent is the current in the circuit exceeding the carrying capacity of the device or line. Once these two faults occur, it is likely to cause device damage, and even cause fire and other serious consequences.

[0003] In the prior art, the protection circuit often adopts a single overcurrent protection or short circuit protection mechanism. However, this single protection method cannot comprehensively cover various fault conditions, and has obvious limitations. For example, some protection circuits can only protect against overcurrent, but cannot effectively respond to short circuits; on the contrary, some other protection circuits can only protect against short circuits, ignoring the risk of overcurrent. CONTENT OF THE UTILITY MODEL

[0004] The purpose of the present disclosure is to overcome the deficiencies in the prior art, and to provide a fault protection circuit and a battery management system capable of limiting overcurrent.

[0005] The purpose of the present disclosure is achieved by the following technical solutions:

[0006] A fault protection circuit, comprising an output sampling circuit, a short circuit detection circuit, an overcurrent detection circuit, a current limiting control circuit, an input control circuit and a microcontroller.

[0007] The output sampling circuit comprises a first electronic switch tube and a first sampling resistor, the control end of the first electronic switch tube is connected with the output end of the input control circuit, the first end of the first electronic switch tube is used for connecting with a power output module, the second end of the first electronic switch tube is connected with the first end of the first sampling resistor, and the second end of the first sampling resistor is grounded.

[0008] The short circuit detection circuit comprises a first voltage dividing resistor, a first delay capacitor and a second electronic switch tube, the first end of the first voltage dividing resistor is connected with the first end of the first sampling resistor, the second end of the first voltage dividing resistor is connected with the control end of the second electronic switch tube, the first end of the first delay capacitor is connected with the control end of the second electronic switch tube, the second end of the first delay capacitor is grounded, the first end of the second electronic switch tube is connected with the short circuit protection signal end of the microcontroller, and the second end of the second electronic switch tube is grounded.

[0009] The overcurrent detection circuit includes a first current-limiting resistor and a first filter capacitor, a first end of the first current-limiting resistor is connected with a first end of the first sampling resistor, a second end of the first current-limiting resistor is connected with an overcurrent sampling signal end of the microcontroller, a first end of the first filter capacitor is connected with the overcurrent sampling signal end of the microcontroller, and a second end of the first filter capacitor is grounded.

[0010] The current-limiting control circuit is used for limiting the current of the first electronic switch tube to prevent the failure current from damaging the first electronic switch tube.

[0011] The input control circuit is used for receiving an enable signal of the microcontroller and controlling the current input of the external power supply end.

[0012] In one of the embodiments, the input control circuit includes a third electronic switch tube, a fourth electronic switch tube, a first bias resistor, a second current-limiting resistor and a third current-limiting resistor, a first end of the third electronic switch tube is used for being connected with the external power supply end, a second end of the third electronic switch tube is connected with a first end of the second current-limiting resistor, a control end of the third electronic switch tube is connected with a first end of the fourth electronic switch tube, a second end of the second current-limiting resistor is connected with a control end of the first electronic switch tube, a first end of the first bias resistor is connected with the first end of the third electronic switch tube, a second end of the first bias resistor is connected with the control end of the third electronic switch tube, a control end of the fourth electronic switch tube is connected with a second end of the third current-limiting resistor, a second end of the fourth electronic switch tube is grounded, and a first end of the third current-limiting resistor is connected with an enable signal end of the microcontroller.

[0013] In one of the embodiments, the input control circuit further includes a second voltage-dividing resistor, a first end of the second voltage-dividing resistor is connected with the second end of the first bias resistor, and a second end of the second voltage-dividing resistor is connected with the first end of the fourth electronic switch tube.

[0014] In one of the embodiments, the input control circuit further includes a third voltage-dividing resistor, a first end of the third voltage-dividing resistor is connected with the control end of the fourth electronic switch tube, and a second end of the third voltage-dividing resistor is grounded.

[0015] In one of the embodiments, the input control circuit further includes a fourth current-limiting resistor, a first end of the fourth current-limiting resistor is connected with the control end of the first electronic switch tube, and a second end of the fourth current-limiting resistor is grounded.

[0016] In one of the embodiments, the short-circuit detection circuit further comprises a fourth voltage dividing resistor, a first end of the fourth voltage dividing resistor is connected with a short-circuit protection signal end of the microcontroller, and a second end of the fourth voltage dividing resistor is connected with a first end of the second electronic switch tube.

[0017] In one of the embodiments, the short-circuit detection circuit further comprises a fifth voltage dividing resistor, a first end of the fifth voltage dividing resistor is connected with a control end of the second electronic switch tube, and a second end of the fifth voltage dividing resistor is grounded.

[0018] In one of the embodiments, the current-limiting control circuit comprises a fifth current-limiting resistor, a sixth voltage dividing resistor and a fifth electronic switch tube, a first end of the fifth current-limiting resistor is connected with a first end of the first sampling resistor, a second end of the fifth current-limiting resistor is connected with a control end of the fifth electronic switch tube, a first end of the sixth voltage dividing resistor is connected with the control end of the fifth electronic switch tube, a second end of the sixth voltage dividing resistor is grounded, a first end of the fifth electronic switch tube is connected with the control end of the first electronic switch tube, and a second end of the fifth electronic switch tube is grounded.

[0019] In one of the embodiments, the output sampling circuit further comprises a second sampling resistor, a first end of the second sampling resistor is connected with the first end of the first sampling resistor, and a second end of the second sampling resistor is grounded.

[0020] The application also provides a battery management system comprising the fault protection circuit of any one of the above embodiments.

[0021] Compared with the prior art, the present disclosure has at least the following advantages:

[0022] 1. The fault protection circuit described above feeds back the output current change of the power output module through the first sampling resistor, converts it into a voltage signal and transmits it to the short-circuit detection circuit and the overcurrent detection circuit, so as to realize double protection of short circuit and overcurrent of the power output module. Specifically, when the short circuit and overcurrent faults occur in the power output module at the same time, the short-circuit detection circuit and the overcurrent detection circuit can both output signals to the microcontroller, and the microcontroller outputs an enable level signal to the input control circuit to control the on-off of the first electronic switch tube, so as to control the working state of the power output module, thereby effectively preventing the damage caused by the fault current to the circuit and the equipment, and improving the safety and reliability of the fault protection circuit.

[0023] 2. On the other hand, when the short-circuit or overcurrent fault occurs, the current-limiting control circuit can quickly reduce the voltage at the control end of the first electronic switch tube, thereby limiting the current flowing into the first electronic switch tube, effectively preventing the damage caused by the excessive current to the components, and reducing the heat generation in the circuit, thereby improving the safety of the fault protection circuit. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a circuit diagram of a fault protection circuit according to one embodiment. Detailed Implementation

[0026] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0027] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments:

[0030] like Figure 1 As shown, a fault protection circuit 10 according to an embodiment of the present disclosure includes an output sampling circuit 100, a short circuit detection circuit 200, an overcurrent detection circuit 300, a current limiting control circuit 400, an input control circuit 500, and a microcontroller.

[0031] The output sampling circuit 100 comprises a first electronic switch tube Q3 and a first sampling resistor RS1. The control end of the first electronic switch tube Q3 is connected with the output end of the input control circuit 500. The first end of the first electronic switch tube Q3 is used for being connected with the power output module J1. The second end of the first electronic switch tube Q3 is connected with the first end of the first sampling resistor RS1. The second end of the first sampling resistor RS1 is grounded.

[0032] The short circuit detection circuit 200 comprises a first voltage dividing resistor R4, a first delay capacitor C1 and a second electronic switch tube Q1. The first end of the first voltage dividing resistor R4 is connected with the first end of the first sampling resistor RS1. The second end of the first voltage dividing resistor R4 is connected with the control end of the second electronic switch tube Q1. The first end of the first delay capacitor C1 is connected with the control end of the second electronic switch tube Q1. The second end of the first delay capacitor C1 is grounded. The first end of the second electronic switch tube Q1 is connected with the short circuit protection signal end SCP-INT of the microcontroller. The second end of the second electronic switch tube Q1 is grounded.

[0033] The overcurrent detection circuit 300 comprises a first current limiting resistor R8 and a first filter capacitor C2. The first end of the first current limiting resistor R8 is connected with the first end of the first sampling resistor RS1. The second end of the first current limiting resistor R8 is connected with the overcurrent sampling signal end DCI-AD of the microcontroller. The first end of the first filter capacitor C2 is connected with the overcurrent sampling signal end DCI-AD of the microcontroller. The second end of the first filter capacitor C2 is grounded.

[0034] The current limiting control circuit 400 is used for limiting the current of the first electronic switch tube Q3 to prevent the damage of the first electronic switch tube Q3 caused by the fault current.

[0035] The input control circuit 500 is used for receiving the enable signal of the microcontroller and controlling the current input of the external power supply end.

[0036] The first end of the first sampling resistor RS1 is also connected with the control end of the short circuit detection circuit 200, the control end of the current limiting control circuit 400 and the input end of the overcurrent detection circuit 300 respectively. The input end of the short circuit detection circuit 200 is connected with the short circuit protection signal end SCP-INT of the microcontroller. The output end of the short circuit detection circuit 200 is grounded. The output end of the overcurrent detection circuit 300 is connected with the overcurrent sampling signal end DCI-AD of the microcontroller. The control end of the input control circuit 500 is connected with the enable signal end DC-EN of the microcontroller. The input end of the input control circuit 500 is used for being connected with the external power supply end. The first end of the current limiting control circuit 400 is connected with the control end of the first electronic switch tube Q3. The output end of the current limiting control circuit 400 is grounded.

[0037] In the embodiment, in normal state, the external power supply end outputs voltage to the control end of the first electronic switch tube Q3 through the input end of the input control circuit 500, so that the voltage of the control end of the first electronic switch tube Q3 is greater than the conduction threshold voltage, so that the first electronic switch tube Q3 is turned on. At this time, the power output module J1 is in normal working state, so that the current can flow to the first sampling resistor RS1 through the first electronic switch tube Q3, and the voltage drop proportional to the current is generated across the first sampling resistor RS1. And the voltage drop of the first sampling resistor RS1 is conducted to the control end of the short circuit detection circuit 200, the control end of the current limiting control circuit 400 and the input end of the overcurrent detection circuit 300, but since the current is in the normal range at this time, any protection mechanism will not be triggered.

[0038] Further, when the power output module J1 has a short circuit fault, the current output by the power output module J1 will increase, so that the current flowing into the first sampling resistor RS1 also increases, and the voltage drop across the first sampling resistor RS1 also increases. At this time, the voltage of the first sampling resistor RS1 is conducted to the control end of the second electronic switch tube Q1, so that the voltage of the control end of the second electronic switch tube Q1 rises. When the voltage of the control end of the second electronic switch tube Q1 is greater than the threshold voltage, the second electronic switch tube Q1 is turned on, so that the second electronic switch tube Q1 pulls the short circuit protection signal end SCP-INT of the microcontroller to low level, and then the low level signal drives the enable signal end DC-EN of the microcontroller to output an enable level signal to the control end of the input control circuit 500, so as to drive the input control circuit 500 to block the current input of the external power supply end, thereby causing the power output module J1 to stop outputting current.

[0039] Further, when the power output module J1 has an overcurrent fault, the voltage drop across the first sampling resistor RS1 increases, and the voltage of the first sampling resistor RS1 is conducted to the first current limiting resistor R8, and then the voltage is output to the overcurrent sampling signal end DCI-AD of the microcontroller, so that the voltage of the overcurrent sampling signal end DCI-AD of the microcontroller is greater than the preset threshold range, thereby driving the enable signal end DC-EN of the microcontroller to output an enable level signal to the control end of the input control circuit 500, causing the input control circuit 500 to block the input of the external power supply end, thereby causing the power output module J1 to stop outputting current.

[0040] Specifically, when the short circuit and overcurrent faults occur simultaneously in the power output module J1, the control end of the second electronic switch tube Q1 and the first current limiting resistor R8 can both obtain the fault voltage through the first sampling resistor RS1, so that the short circuit detection circuit 200 and the overcurrent detection circuit 300 can both drive the enable signal end DC-EN of the microcontroller to output an enable level signal, so that the input control circuit 500 stops working and blocks the current loop, and then the fault protection circuit 10 plays a protection role.

[0041] On the other hand, when the overcurrent or short circuit fault occurs in the power output module J1, the voltage raised by the first sampling resistor RS1 will be conducted to the control end of the current limiting control circuit 400, so that the current limiting control circuit 400 enters the working state. Since the input end of the current limiting control circuit 400 is connected with the control end of the first electronic switch tube Q3, and the output end of the current limiting control circuit 400 is connected with the ground, the voltage at the control end of the first electronic switch tube Q3 is lowered, and then the current flowing into the first electronic switch tube Q3 is limited, so as to avoid the damage to the first electronic switch tube Q3 and the components in the circuit caused by the excessive current.

[0042] The above-mentioned fault protection circuit 10 feeds back the output current change of the power output module J1 through the first sampling resistor RS1, and converts it into a voltage signal transmitted to the short circuit detection circuit 200 and the overcurrent detection circuit 300, so as to realize the double protection of the short circuit and overcurrent of the power output module J1. Specifically, when the short circuit and overcurrent faults occur simultaneously in the power output module J1, the short circuit detection circuit 200 and the overcurrent detection circuit 300 can both output signals to the microcontroller, and output an enable level signal to the input control circuit through the microcontroller, so as to control the on-off of the first electronic switch tube Q3, and then control the working state of the power output module J1, so as to effectively prevent the damage to the circuit and the equipment caused by the fault current, and improve the safety and reliability of the fault protection circuit 10. On the other hand, when the short circuit or overcurrent fault occurs, the current limiting control circuit 400 can quickly lower the voltage at the control end of the first electronic switch tube Q3, so as to limit the current flowing into the first electronic switch tube Q3, effectively prevent the damage to the components caused by the excessive current, and reduce the heat generated in the circuit, and then improve the safety of the fault protection circuit 10.

[0043] In another embodiment, the first electronic switch tube Q3 is an N-channel MOS tube, the first end of the first electronic switch tube Q3 is the drain of the N-channel MOS tube, the second end of the first electronic switch tube Q3 is the source of the N-channel MOS tube, and the control end of the first electronic switch tube Q3 is the gate of the N-channel MOS tube.

[0044] As Figure 1As shown, in one of the embodiments, the input control circuit 500 includes a third electronic switch tube Q2, a fourth electronic switch tube Q5, a first bias resistor R5, a second current limiting resistor R3 and a third current limiting resistor R11. The first end of the third electronic switch tube Q2 is connected with the external power supply end, the second end of the third electronic switch tube Q2 is connected with the first end of the second current limiting resistor R3, the control end of the third electronic switch tube Q2 is connected with the first end of the fourth electronic switch tube Q5, the second end of the second current limiting resistor R3 is connected with the control end of the first electronic switch tube Q3, the first end of the first bias resistor R5 is connected with the first end of the third electronic switch tube Q2, the second end of the first bias resistor R5 is connected with the control end of the third electronic switch tube Q2, the control end of the fourth electronic switch tube Q5 is connected with the second end of the third current limiting resistor R11, the second end of the fourth electronic switch tube Q5 is grounded, and the first end of the third current limiting resistor R11 is connected with the enable signal end DC-EN of the microcontroller. In this embodiment, the first end of the third electronic switch tube Q2 is connected with the external power supply end, for receiving the voltage provided by the external power supply. And the second end of the third electronic switch tube Q2 is connected with the control end of the first electronic switch tube Q3 through the second current limiting resistor R3, to limit the current flowing into the control end of the first electronic switch tube Q3, so as to prevent the damage of the components caused by the excessive current. Since the first bias resistor R5 is connected between the first end of the third electronic switch tube Q2 and the control end of the third electronic switch tube Q2, a stable bias voltage is provided for the third electronic switch tube Q2, so as to ensure that the third electronic switch tube Q2 remains in the conduction state under normal circumstances, allowing the external power supply end to provide power to the subsequent circuit through the input control circuit 500.

[0045] Specifically, when a short circuit or overcurrent fault occurs in the circuit, the enable signal end DC-EN of the microcontroller outputs a high level. Since the control end of the fourth electronic switch tube Q5 is connected with the enable signal end DC-EN of the microcontroller through the third current limiting resistor R11, the voltage at the control end of the fourth electronic switch tube Q5 is greater than its conduction threshold voltage, so that the fourth electronic switch tube Q5 is turned on. At the same time, since the control end of the third electronic switch tube Q2 is connected with the first end of the fourth electronic switch tube Q5, and the second end of the fourth electronic switch tube Q5 is grounded, the voltage at the control end of the third electronic switch tube Q2 is reduced, which in turn causes the third electronic switch tube Q2 to be turned off. At this time, since the third electronic switch tube Q2 is turned off, the current cannot flow through the third electronic switch tube Q2 to the first electronic switch tube Q3, so that the power output module J1 stops outputting current, thereby achieving effective protection of the circuit. On the other hand, the second current limiting resistor R3 and the third current limiting resistor R11 play a role in limiting current in the circuit, so as to prevent excessive current impact during switching, thereby protecting the electronic switch tube and other components from damage.

[0046] In another embodiment, the third electronic switch Q2 is an N-channel MOSFET, with its first terminal serving as the drain, its second terminal as the source, and its control terminal as the gate. The fourth electronic switch Q5 is an NPN transistor, with its first terminal serving as the collector, its second terminal as the emitter, and its control terminal as the base.

[0047] like Figure 1 As shown, in one embodiment, the input control circuit 500 further includes a second voltage divider resistor R9. The first end of the second voltage divider resistor R9 is connected to the second end of the first bias resistor R5, and the second end of the second voltage divider resistor R9 is connected to the first end of the fourth electronic switch Q5. In this embodiment, the first bias resistor R5 provides a stable bias voltage to the third electronic switch Q2, ensuring that it remains in the conducting state under normal conditions. When the external power supply voltage is high, the second voltage divider resistor R9 and the first bias resistor R5 work together to divide the voltage, preventing the voltage at the control terminal of the third electronic switch Q2 from becoming too high, thus avoiding damage or unstable operation of the third electronic switch Q2 due to excessive voltage. Simultaneously, by adjusting the resistance value of the second voltage divider resistor R9, the voltage level at the control terminal of the third electronic switch Q2 can be flexibly adjusted to meet the needs of different circuit designs.

[0048] like Figure 1 As shown, in one embodiment, the input control circuit 500 further includes a third voltage divider resistor R12. The first end of the third voltage divider resistor R12 is connected to the control terminal of the fourth electronic switch Q5, and the second end of the third voltage divider resistor R12 is grounded. In this embodiment, when the current of the power output module J1 suddenly increases, the overcurrent detection circuit 300 drives the enable signal terminal DC-EN of the microcontroller to output a high-level signal to the control terminal of the fourth electronic switch Q5. Since the third voltage divider resistor R12 and the third current limiting resistor R11 together form a voltage divider circuit, the voltage at the control terminal of the fourth electronic switch Q5 is effectively limited, thereby preventing damage caused by excessive voltage at the control terminal of the fourth electronic switch Q5. In addition, when the fourth electronic switch Q5 is turned off, the voltage at its control terminal can be discharged to the ground terminal through the third voltage divider resistor R12, thereby preventing impact or damage to other components in the circuit due to voltage surges.

[0049] like Figure 1As shown, in one embodiment, the input control circuit further comprises a fourth current-limiting resistor R6, a first end of the fourth current-limiting resistor R6 is connected to the control end of the first electronic switch tube Q3, and a second end of the fourth current-limiting resistor R6 is grounded. In this embodiment, in the normal working state, the external power supply end provides the control end of the first electronic switch tube Q3 with a voltage required for conduction through the input control circuit. At this time, the fourth current-limiting resistor R6 limits the input current, avoiding abnormal fluctuations of the external power supply from being conducted to the control end of the first electronic switch tube Q3, thereby ensuring that the control end of the first electronic switch tube Q3 will not be affected by a small interference current in the normal working state, and further maintaining the stable operation of the fault protection circuit 10.

[0050] As shown, Figure 1 As shown, in one embodiment, the short-circuit detection circuit further comprises a fourth voltage dividing resistor R1, a first end of the fourth voltage dividing resistor R1 is connected to the short-circuit protection signal end SCP-INT of the microcontroller, and a second end of the fourth voltage dividing resistor R1 is connected to the first end of the second electronic switch tube Q1. In this embodiment, when the power output module J1 has a short-circuit fault, the voltage drop across the first sampling resistor RS1 increases sharply, causing the control end voltage of the second electronic switch tube Q1 to rise. When the control end voltage of the second electronic switch tube Q1 exceeds the threshold voltage, the second electronic switch tube Q1 is turned on, the electrical signal of the short-circuit protection signal end SCP-INT is conducted to the first end of the second electronic switch tube Q1 through the fourth voltage dividing resistor R1, and then the second end of the second electronic switch tube Q1 connects the short-circuit protection signal end SCP-INT of the microcontroller to the ground end, so that the short-circuit protection signal end SCP-INT is pulled to a low level. And in this process, the fourth voltage dividing resistor R1 limits the current size between the short-circuit protection signal end SCP-INT of the microcontroller and the second electronic switch tube Q1, thereby avoiding damage to the second electronic switch tube Q1 due to excessive current in the conduction moment.

[0051] As shown, Figure 1As shown, in one embodiment, the short circuit detection circuit 200 further comprises a fifth voltage dividing resistor R2, a first end of the fifth voltage dividing resistor R2 is connected to the control end of the second electronic switch tube Q1, and a second end of the fifth voltage dividing resistor R2 is grounded. In this embodiment, under normal working conditions, the fifth voltage dividing resistor R2 and the first delay capacitor C1 together ensure the stability of the voltage at the control end of the second electronic switch tube Q1, preventing false triggering caused by small fluctuations or noise in the circuit. When a short circuit fault occurs in the power output module J1, the current of the first sampling resistor RS1 increases sharply, and the voltage drop across the first sampling resistor RS1 also increases significantly, and is conducted to the first delay capacitor C1 through the first voltage dividing resistor R4, causing the voltage at the control end of the second electronic switch tube Q1 to begin to rise. In this process, the fifth voltage dividing resistor R2 and the first delay capacitor C1 together form a low-pass filter, which smooths the rapidly changing voltage signal, thereby helping to reduce false actions caused by voltage surges, and further ensuring that the short circuit detection circuit 200 can respond quickly and accurately when a short circuit occurs. At the same time, the fifth voltage dividing resistor R2 and the first voltage dividing resistor R4 together form a voltage dividing network, further delaying the triggering of the short circuit protection mechanism to prevent the problem of false shutdown caused by fluctuations in the circuit.

[0052] In another embodiment, the second electronic switch tube Q1 is an NPN type triode, the first end of the second electronic switch tube Q1 is the collector of the NPN type triode, the second end of the second electronic switch tube Q1 is the emitter of the NPN type triode, and the control end of the second electronic switch tube Q1 is the base of the NPN type triode.

[0053] As Figure 1As shown, in one embodiment, the current limiting control circuit 400 includes a fifth current limiting resistor R7, a sixth voltage dividing resistor R10 and a fifth electronic switch Q4. The first end of the fifth current limiting resistor R7 is connected to the first end of the first sampling resistor RS1. The second end of the fifth current limiting resistor R7 is connected to the control end of the fifth electronic switch Q4. The first end of the sixth voltage dividing resistor R10 is connected to the control end of the fifth electronic switch Q4. The second end of the sixth voltage dividing resistor R10 is grounded. The first end of the fifth electronic switch Q4 is connected to the control end of the first electronic switch Q3. The second end of the fifth electronic switch Q4 is grounded. In this embodiment, the first end of the fifth current limiting resistor R7 is connected to the first end of the first sampling resistor RS1, so that the fifth current limiting resistor R7 can monitor the voltage change on the first sampling resistor RS1, and the voltage change is proportional to the current of the power output module J1. When the power output module J1 has an overcurrent or short circuit fault, the output current increases sharply, causing the voltage drop across the first sampling resistor RS1 to rise significantly. The rising voltage signal is conducted to the control end of the fifth electronic switch Q4 through the fifth current limiting resistor R7, so that the control end voltage of the fifth electronic switch Q4 rises to make the fifth electronic switch Q4 conductive. Since the first end of the fifth electronic switch Q4 is connected to the control end of the first electronic switch Q3, and the second end is connected to the ground, when the fifth electronic switch Q4 is conductive, the current at the control end of the first electronic switch Q3 will be conducted to the ground through the fifth electronic switch Q4, thereby avoiding damage to the first electronic switch Q3 caused by excessive current. In addition, by adjusting the resistance of the first sampling resistor RS1, the fifth current limiting resistor R7 and the sixth voltage dividing resistor R10, the size of the limiting current and the protection delay time can be flexibly changed to adapt to different application requirements.

[0054] In another embodiment, the fifth electronic switch Q4 is an NPN transistor. The first end of the fifth electronic switch Q4 is the collector of the NPN transistor. The second end of the fifth electronic switch Q4 is the emitter of the NPN transistor. The control end of the fifth electronic switch Q4 is the base of the NPN transistor.

[0055] As Figure 1As shown, in one embodiment, the output sampling circuit 100 further comprises a second sampling resistor RS2, a first end of the second sampling resistor RS2 is connected with the first end of the first sampling resistor RS1, and a second end of the second sampling resistor RS2 is grounded. In this embodiment, since the resistance values of the two sampling resistors are fixed, according to the characteristics of parallel resistors and Ohm's law, the voltage drops generated across each of them can accurately reflect the current flowing through itself. When the power output module J1 has a short circuit and overcurrent fault, the output current of the power output module J1 will increase sharply, causing the current flowing through the first sampling resistor RS1 and the second sampling resistor RS2 to increase significantly, and the voltage drops across the two sampling resistors will also increase significantly. At this time, the increased voltage drops of the first sampling resistor RS1 and the second sampling resistor RS2 will be conducted to the control end of the short circuit detection circuit 200 and the input end of the overcurrent detection circuit 300, thereby avoiding the problem that the protection mechanism fails due to a single sampling resistor fault. In addition, since the second sampling resistor RS2 is connected in parallel with the first sampling resistor RS1, it provides an additional current path, which helps to disperse the current and reduce the power dissipation on a single sampling resistor, thereby protecting the sampling resistor from being damaged due to overcurrent.

[0056] The application also provides a battery management system comprising the fault protection circuit 10 of any of the above embodiments. In this embodiment, under normal conditions, the external power supply end outputs voltage to the control end of the first electronic switch tube Q3 through the input end of the input control circuit 500, so that the voltage at the control end of the first electronic switch tube Q3 is greater than its conduction threshold voltage, so that the first electronic switch tube Q3 is turned on. At this time, the power output module J1 is in a normal working state, so that the current can flow to the first sampling resistor RS1 through the first electronic switch tube Q3, and a voltage drop proportional to the current will be generated across the first sampling resistor RS1. And the voltage drop of the first sampling resistor RS1 will be conducted to the control end of the short circuit detection circuit 200, the control end of the current limiting control circuit 400 and the input end of the overcurrent detection circuit 300, but since the current is within the normal range at this time, any protection mechanism will not be triggered. Further, when the power output module J1 has a short circuit fault, the current output by the power output module J1 will increase, so that the current flowing into the first sampling resistor RS1 also increases, and the voltage drop across the first sampling resistor RS1 also increases. At this time, the voltage of the first sampling resistor RS1 will be conducted to the control end of the second electronic switch tube Q1, so that the voltage at the control end of the second electronic switch tube Q1 rises. When the voltage at the control end of the second electronic switch tube Q1 is greater than its threshold voltage, the second electronic switch tube Q1 is turned on, so that the second electronic switch tube Q1 pulls the short circuit protection signal end SCP-INT of the microcontroller to a low level, and then the low level signal drives the enable signal end DC-EN of the microcontroller to output an enable level signal to the control end of the input control circuit 500, so as to drive the input control circuit 500 to block the current input of the external power supply end, thereby causing the power output module J1 to stop outputting current. Further, when the power output module J1 has an overcurrent fault, the voltage drop across the first sampling resistor RS1 increases, and the voltage of the first sampling resistor RS1 will be conducted to the first current limiting resistor R8, and then output to the overcurrent sampling signal end DCI-AD of the microcontroller, so that the voltage at the overcurrent sampling signal end DCI-AD of the microcontroller is greater than its preset threshold range, thereby driving the enable signal end DC-EN of the microcontroller to output an enable level signal to the control end of the input control circuit 500, causing the input control circuit 500 to block the input of the external power supply end, thereby causing the power output module J1 to stop outputting current. Specifically, when the power output module J1 has both a short circuit fault and an overcurrent fault, the control end of the second electronic switch tube Q1 and the first current limiting resistor R8 can both obtain fault voltage through the first sampling resistor RS1, so that the short circuit detection circuit 200 and the overcurrent detection circuit 300 can drive the enable signal end DC-EN of the microcontroller to output an enable level signal, thereby causing the input control circuit 500 to stop working and block the current loop, thereby causing the fault protection circuit 10 to play a protection role.On the other hand, when the power output module J1 has an overcurrent or short circuit fault, the voltage of the first sampling resistor RS1 rising will be transmitted to the control end of the current limiting control circuit 400, so that the current limiting control circuit 400 enters the working state. Since the input end of the current limiting control circuit 400 is connected with the control end of the first electronic switch tube Q3, and the output end of the current limiting control circuit 400 is connected with the ground, the voltage of the control end of the first electronic switch tube Q3 is reduced, thereby limiting the current flowing into the first electronic switch tube Q3, so as to avoid the damage of excessive current to the first electronic switch tube Q3 and the components in the circuit.

[0057] Compared with the prior art, the present disclosure has at least the following advantages:

[0058] 1. The fault protection circuit 10 described above, the output current change of the power output module J1 is fed back through the first sampling resistor RS1, and is converted into a voltage signal and transmitted to the short circuit detection circuit 200 and the overcurrent detection circuit 300, so as to realize the double protection of the short circuit and overcurrent of the power output module J1. Specifically, when the power output module J1 has a short circuit and overcurrent fault at the same time, the short circuit detection circuit 200 and the overcurrent detection circuit 300 can output signals to the microcontroller, and output an enable level signal to the input control circuit through the microcontroller, so as to control the on-off of the first electronic switch tube Q3, thereby controlling the working state of the power output module J1, and effectively preventing the damage of the fault current to the circuit and the equipment, and improving the safety and reliability of the fault protection circuit 10.

[0059] 2. On the other hand, when the short circuit or overcurrent fault occurs, the current limiting control circuit 400 can quickly reduce the voltage of the control end of the first electronic switch tube Q3, thereby limiting the current flowing into the first electronic switch tube Q3, effectively preventing the damage of excessive current to the components, and reducing the heat generation in the circuit, thereby improving the safety of the fault protection circuit 10.

[0060] The above-described embodiments only express several embodiments of the present disclosure, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the disclosed patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present disclosure, a number of modifications and improvements can be made, which are within the scope of protection of the present disclosure. Therefore, the protection scope of the present disclosure patent should be subject to the appended claims.

Claims

1. A fault protection circuit, characterized in that, It includes an output sampling circuit, a short-circuit detection circuit, an overcurrent detection circuit, a current limiting control circuit, an input control circuit, and a microcontroller. The output sampling circuit includes a first electronic switch and a first sampling resistor. The control terminal of the first electronic switch is connected to the output terminal of the input control circuit. The first terminal of the first electronic switch is used to connect to the power output module. The second terminal of the first electronic switch is connected to the first terminal of the first sampling resistor. The second terminal of the first sampling resistor is grounded. The short-circuit detection circuit includes a first voltage divider resistor, a first delay capacitor, and a second electronic switch. The first end of the first voltage divider resistor is connected to the first end of the first sampling resistor, the second end of the first voltage divider resistor is connected to the control terminal of the second electronic switch, the first end of the first delay capacitor is connected to the control terminal of the second electronic switch, the second end of the first delay capacitor is grounded, the first end of the second electronic switch is connected to the short-circuit protection signal terminal of the microcontroller, and the second end of the second electronic switch is grounded. The overcurrent detection circuit includes a first current-limiting resistor and a first filter capacitor. The first end of the first current-limiting resistor is connected to the first end of the first sampling resistor, the second end of the first current-limiting resistor is connected to the overcurrent sampling signal terminal of the microcontroller, the first end of the first filter capacitor is connected to the overcurrent sampling signal terminal of the microcontroller, and the second end of the first filter capacitor is grounded. The current limiting control circuit is used to limit the current of the first electronic switch to prevent fault current from damaging the first electronic switch. The input control circuit is used to receive the enable signal from the microcontroller and control the current input to the external power supply terminal.

2. The fault protection circuit according to claim 1, characterized in that, The input control circuit includes a third electronic switch, a fourth electronic switch, a first bias resistor, a second current-limiting resistor, and a third current-limiting resistor. The first terminal of the third electronic switch is connected to an external power supply terminal. The second terminal of the third electronic switch is connected to the first terminal of the second current-limiting resistor. The control terminal of the third electronic switch is connected to the first terminal of the fourth electronic switch. The second terminal of the second current-limiting resistor is connected to the control terminal of the first electronic switch. The first terminal of the first bias resistor is connected to the first terminal of the third electronic switch. The second terminal of the first bias resistor is connected to the control terminal of the third electronic switch. The control terminal of the fourth electronic switch is connected to the second terminal of the third current-limiting resistor. The second terminal of the fourth electronic switch is grounded. The first terminal of the third current-limiting resistor is connected to the enable signal terminal of the microcontroller.

3. The fault protection circuit according to claim 2, characterized in that, The input control circuit further includes a second voltage divider resistor, the first end of which is connected to the second end of the first bias resistor, and the second end of which is connected to the first end of the fourth electronic switch.

4. The fault protection circuit according to claim 2, characterized in that, The input control circuit also includes a third voltage divider resistor, the first end of which is connected to the control terminal of the fourth electronic switch, and the second end of which is grounded.

5. The fault protection circuit according to claim 2, characterized in that, The input control circuit further includes a fourth current-limiting resistor, the first end of which is connected to the control terminal of the first electronic switch, and the second end of which is grounded.

6. The fault protection circuit according to claim 1, characterized in that, The short-circuit detection circuit further includes a fourth voltage divider resistor, the first end of which is connected to the short-circuit protection signal terminal of the microcontroller, and the second end of which is connected to the first end of the second electronic switch.

7. The fault protection circuit according to claim 6, characterized in that, The short-circuit detection circuit further includes a fifth voltage divider resistor, the first end of which is connected to the control terminal of the second electronic switch, and the second end of which is grounded.

8. The fault protection circuit according to claim 1, characterized in that, The current limiting control circuit includes a fifth current limiting resistor, a sixth voltage dividing resistor, and a fifth electronic switch. The first end of the fifth current limiting resistor is connected to the first end of the first sampling resistor, and the second end of the fifth current limiting resistor is connected to the control terminal of the fifth electronic switch. The first end of the sixth voltage dividing resistor is connected to the control terminal of the fifth electronic switch, and the second end of the sixth voltage dividing resistor is grounded. The first end of the fifth electronic switch is connected to the control terminal of the first electronic switch, and the second end of the fifth electronic switch is grounded.

9. The fault protection circuit according to claim 1, characterized in that, The output sampling circuit further includes a second sampling resistor, the first end of which is connected to the first end of the first sampling resistor, and the second end of which is grounded.

10. A battery management system, characterized in that, Includes the fault protection circuit described in any one of claims 1 to 9.

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