Over-current protection circuit, single-phase over-current protection circuit and multi-phase over-current protection circuit
By introducing a driving unit, a voltage division unit, a current limiting unit and a acquisition unit into the current protection circuit, real-time monitoring and control of the current of the switch tube is solved, and the problems of long reaction time and accuracy error of the existing current protection circuit are achieved, and efficient and accurate overcurrent protection is achieved.
Patent Information
- Application Number
- CN202420753374.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-11
- Publication Date
- 2025-05-06
- Estimated Expiration
- 2034-04-11
AI Technical Summary
When the existing current protection circuit realizes current protection, the reaction time is long, the accuracy error is present, and the cost is high, making it difficult to meet the high requirements of voltage and current safety in the new energy transportation industry.
By introducing a driving unit, a voltage divider unit, a current limiting unit and a acquisition unit into the circuit, the conversion of the voltage divider current and the acquisition current can realize real-time monitoring and control of the switching tube current, and avoid short circuits when the current is too large.
It realizes overcurrent protection without the need for a current sensor, improves protection accuracy, shortens response time, and reduces the area occupied by the protection circuit.
Smart Images
Figure CN222839411U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of power electronics, and in particular to an overcurrent protection circuit, a single-phase overcurrent protection circuit and a multi-phase overcurrent protection circuit. Background Art
[0002] With the rapid development of the new energy transportation industry, the voltage and current safety requirements of the devices used are becoming increasingly higher. How to accurately, quickly and efficiently implement current protection has become an important issue that hardware engineers need to solve.
[0003] At present, the more popular current protection circuit first detects the current through the current sensor, and then determines whether it is necessary to send a signal to the MCU (Micro Control Unit) to trigger the protection through the comparator circuit. Although the response time of some current sensors is now quite fast, the corresponding cost will also increase. For general current sensors, a response time of microseconds is still required. In addition, the current passing through the current sensor will also cause some accuracy errors. Utility Model Content
[0004] The embodiments of the present application provide an overcurrent protection circuit, a single-phase overcurrent protection circuit and a multi-phase overcurrent protection circuit, which realize overcurrent protection without the need for a current sensor, improve the accuracy of overcurrent protection and shorten the response time.
[0005] In a first aspect, an embodiment of the present application provides an overcurrent protection circuit, comprising: a driving unit, a voltage dividing unit, a current limiting unit and a collection unit; the driving unit is connected to a control device, the driving unit is connected to a control end of a switch tube Q1 through the current limiting unit, the driving unit is connected to a second end of the switch tube Q1 through the voltage dividing unit, and the driving unit is also connected to a third end of the switch tube Q1; the driving unit is used to receive a PWM signal from the control device, and output a switch tube control signal to the control end of the switch tube Q1 through the current limiting unit according to the PWM signal to control the on / off state of the switch tube Q1; the voltage dividing unit is used to divide the voltage at the second end of the switch tube Q1 when the switch tube Q1 is turned on, so as to output a voltage-divided current to the collection unit; the collection unit is used to convert the voltage-divided current into a collection current when receiving the voltage-divided current, and output the collection current to the driving unit; the driving unit is also used to receive the collection current, and when the collection current is greater than a first preset current, output a first control signal to the control end of the switch tube Q1 to turn off the switch tube Q1.
[0006] In some embodiments, the driving unit includes a chip U1, a capacitor C1, a capacitor C2, a capacitor C3, a diode D2, a resistor R2, and a resistor R7; the VCC terminal of the chip U1 is connected to the COM terminal of the chip U1 through the capacitor C1, the VCC terminal of the chip U1 is also connected to the first power supply, the COM terminal of the chip U1 is also connected to the positive electrode of the diode D2 and grounded, the IN terminal of the chip U1 is connected to the control device through the resistor R1, the FLT terminal of the chip U1 is connected to the control device through the resistor R2, the FIT terminal of the chip U1 is also grounded through the capacitor C2, the VB terminal of the chip U1 is connected to the VS terminal of the chip U1 through the capacitor C3, the VS terminal of the chip U1 is also connected to the negative electrode of the diode D2 and the first end of the resistor R7, the second end of the resistor R7 is connected to the third end of the switch tube Q1, the HO terminal of the chip U1 is connected to the voltage divider unit and the current limiting unit, and the CS terminal of the chip U1 is connected to the acquisition unit.
[0007] In some embodiments, the voltage dividing unit includes a resistor R3, a resistor R4, and a diode D1; the first end of the resistor R3 is connected to the driving unit, the second end of the resistor R3 is connected to the first end of the resistor R4 and the acquisition unit, the second end of the resistor R4 is connected to the positive electrode of the diode D1, and the negative electrode of the diode D1 is connected to the second end of the switch tube Q1.
[0008] In some embodiments, the current limiting unit includes a resistor R6 and a capacitor C5; the first end of the resistor R6 is connected to the driving unit, the second end of the resistor R6 is connected to the first end of the capacitor C5 and the control end of the switch tube Q1, and the second end of the capacitor C5 is connected to the third end of the switch tube Q1 and is grounded.
[0009] In some embodiments, the acquisition unit includes a resistor R5 and a capacitor C4; the first end of the resistor R5 is connected to the voltage divider unit, the second end of the resistor R5 is connected to the first end of the capacitor C4 and the driving unit, and the second end of the capacitor C4 is connected to the driving unit.
[0010] In the second aspect, an embodiment of the present application provides a single-phase overcurrent protection circuit, which includes two overcurrent protection circuits as described above, and the two overcurrent protection circuits are respectively a first overcurrent protection circuit and a second overcurrent protection circuit; the single-phase overcurrent protection circuit is connected to a single-phase bridge arm, and the single-phase bridge arm includes an upper switch tube Q1 and a lower switch tube Q2, the first overcurrent protection circuit is connected to the upper switch tube Q1, the second overcurrent protection circuit is connected to the lower switch tube Q2, the third end of the upper switch tube Q1 is connected to the second end of the lower switch tube Q2, and the third end of the lower switch tube Q2 is grounded.
[0011] In some embodiments, the first overcurrent protection circuit includes a first driving unit, a first voltage dividing unit, a first current limiting unit and a first acquisition unit; the first driving unit is connected to the control end of the upper switch tube Q1 through the first current limiting unit, the first driving unit is connected to the second end of the upper switch tube Q1 through the first voltage dividing unit, and the first driving unit is also connected to the third end of the upper switch tube Q1; the first driving unit is used to receive a first PWM signal, and output a first switch control signal to the control end of the upper switch tube Q1 through the first current limiting unit according to the first PWM signal to control the on-off state of the upper switch tube Q1; the first voltage dividing unit is used to divide the voltage of the second end of the upper switch tube Q1 when the upper switch tube Q1 is turned on, so as to output a first voltage dividing current to the first acquisition unit; the first acquisition unit is used to convert the first voltage dividing current into a first acquisition current when receiving the first voltage dividing current, and output the first acquisition current to the first driving unit; the first driving unit is also used to receive the first acquisition current, and when the first acquisition current is greater than a second preset current, output a second control signal to the control end of the upper switch tube Q1 to turn off the upper switch tube Q1.
[0012] In some embodiments, the second overcurrent protection circuit includes a second driving unit, a second voltage dividing unit, a second current limiting unit and a second collecting unit; the second driving unit is connected to the control end of the lower switch tube Q2 through the second current limiting unit, the second driving unit is connected to the second end of the lower switch tube Q2 through the second voltage dividing unit, and the second driving unit is also connected to the third end of the lower switch tube Q2; the second driving unit is used to receive a second PWM signal, and output a second switch control signal to the control end of the lower switch tube Q2 through the second current limiting unit according to the second PWM signal to control the on-off state of the lower switch tube Q2; the second voltage dividing unit is used to divide the voltage of the second end of the lower switch tube Q2 when the lower switch tube Q2 is turned on, so as to output a second voltage dividing current to the second collecting unit; the second collecting unit is used to convert the second voltage dividing current into a second collecting current when receiving the second voltage dividing current, and output the second collecting current to the second driving unit; the second driving unit is also used to receive the second collecting current, and when the second collecting current is greater than the third preset current, output a third control signal to the control end of the lower switch tube Q2 to turn off the lower switch tube Q2.
[0013] In a third aspect, an embodiment of the present application provides a multi-phase inverter circuit, comprising at least two single-phase overcurrent protection circuits as described above; each of the at least two single-phase overcurrent protection circuits is respectively connected to a single-phase bridge arm.
[0014] The embodiments of the present application provide an overcurrent protection circuit, a single-phase overcurrent protection circuit and a multi-phase overcurrent protection circuit, and the overcurrent protection circuit includes a driving unit, a voltage dividing unit, a current limiting unit and a collection unit. When the switch tube Q1 is turned on, the voltage dividing unit divides the voltage at the second end of the switch tube Q1 to output the divided current to the collection unit; when the collection unit receives the divided current, it converts the divided current into a collection current and outputs the collection current to the driving unit; when the collection current is greater than the first preset current, the driving unit outputs a first control signal to the control end of the switch tube Q1 to turn off the switch tube Q1. When the current of the switch tube Q1 is too large, the switch tube Q1 can be controlled to be turned off to protect the circuit structure. The embodiments of the present application can realize overcurrent protection without a current sensor, improve the accuracy of overcurrent protection, shorten the response time, and reduce the area occupied by the protection circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.
[0016] Figure 1 is a structural block diagram of an overcurrent protection circuit provided in an embodiment of the present application;
[0017] Figure 2 is a circuit structure diagram of an overcurrent protection circuit provided in an embodiment of the present application;
[0018] Figure 3 It is a structural block diagram of a single-phase overcurrent protection circuit provided in an embodiment of the present application;
[0019] Figure 4 It is a circuit structure schematic diagram of a single-phase overcurrent protection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION
[0020] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0021] The technical features involved in the various embodiments of the present application described below do not conflict with each other and can be combined with each other.
[0022] When an element is referred to as being “connected to” another element, it can be directly connected to the other element, or one or more intervening elements may be present therebetween.
[0023] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more.
[0024] See also Figure 1 , Figure 1 It is a structural block diagram of an overcurrent protection circuit 100 provided in an embodiment of the present application.
[0025] An embodiment of the present application provides an overcurrent protection circuit 100 , including a driving unit 10 , a voltage dividing unit 20 , a current limiting unit 40 and a collection unit 30 .
[0026] Specifically, the drive unit 10 is connected to the control device, the drive unit 10 is connected to the control end of the switch tube Q1 through the current limiting unit 40, the drive unit 10 is connected to the second end of the switch tube Q1 through the voltage dividing unit 20, and the drive unit 10 is also connected to the third end of the switch tube Q1. The second end of the switch tube Q1 is connected to the DC power supply DC, and the DC power supply DC supplies power to the switch tube Q1.
[0027] The switch tube Q1 is an NMOS tube, the gate of the switch tube Q1 is the control end of the switch tube Q1 , the drain of the switch tube Q1 is the second end of the switch tube Q1 , and the source of the switch tube Q1 is the third end of the switch tube Q1 .
[0028] In this embodiment, the driving unit 10 is used to receive a PWM signal from a control device, and output a switch control signal to the control end of the switch Q1 through the current limiting unit 40 according to the PWM signal to control the on / off state of the switch Q1; the voltage dividing unit 20 is used to divide the voltage at the second end of the switch Q1 when the switch Q1 is turned on, so as to output a divided current to the collection unit 30; the collection unit 30 is used to convert the divided current into a collection current when receiving the divided current, and output the collection current to the driving unit 10; the driving unit 10 is also used to receive the collection current, and when the collection current is greater than the first preset current, output a first control signal to the control end of the switch Q1 to turn off the switch Q1.
[0029] The control device is usually a device such as an MCU (Micro Control Unit) that can be used to output a PWM (Pulse Width Modulation) signal to control the switch tube.
[0030] The value of the first preset current is determined by the circuit elements and the connection relationship between the circuit elements, and is not specifically limited here.
[0031] The embodiment of the present application provides an overcurrent protection circuit 100, which includes a driving unit 10, a voltage dividing unit 20, a current limiting unit 40 and a collection unit 30. When the switch tube Q1 is turned on, the voltage dividing unit 20 divides the voltage at the second end of the switch tube Q1 to output the divided current to the collection unit 30; when the collection unit 30 receives the divided current, it converts the divided current into a collection current and outputs the collection current to the driving unit 10; when the collection current is greater than the first preset current, the driving unit 10 outputs a first control signal to the control end of the switch tube Q1 to turn off the switch tube Q1. When the current of the switch tube Q1 is too large, the switch tube Q1 can be controlled to be turned off to protect the circuit structure. The embodiment of the present application can realize overcurrent protection without a current sensor, improve the accuracy of overcurrent protection, shorten the response time, and reduce the area occupied by the protection circuit.
[0032] See also Figure 2 , Figure 2 It is a circuit structure schematic diagram of an overcurrent protection circuit provided in an embodiment of the present application.
[0033] In some embodiments, the driving unit 10 includes a chip U1, a capacitor C1, a capacitor C2, a capacitor C3, a diode D2, a resistor R2, and a resistor R7. Specifically, the VCC terminal of the chip U1 is connected to the COM terminal of the chip U1 through the capacitor C1, the VCC terminal of the chip U1 is also connected to the first power supply, the COM terminal of the chip U1 is also connected to the positive electrode of the diode D2 and grounded, the IN terminal of the chip U1 is connected to the control device through the resistor R1, the FLT terminal of the chip U1 is connected to the control device through the resistor R2, the FIT terminal of the chip U1 is also grounded through the capacitor C2, the VB terminal of the chip U1 is connected to the VS terminal of the chip U1 through the capacitor C3, the VS terminal of the chip U1 is also connected to the negative electrode of the diode D2 and the first end of the resistor R7, the second end of the resistor R7 is connected to the third end of the switch tube Q1, the HO terminal of the chip U1 is connected to the voltage divider unit 20 and the current limiting unit 40, and the CS terminal of the chip U1 is connected to the acquisition unit 30.
[0034] In some embodiments, the chip U1 may be a chip of model TR21276 or other types of chips. The first power supply and the second power supply may be set according to actual needs and are not specifically limited here.
[0035] In some embodiments, the voltage dividing unit 20 includes a resistor R3, a resistor R4, and a diode D1. Specifically, the first end of the resistor R3 is connected to the driving unit 10, the second end of the resistor R3 is connected to the first end of the resistor R4 and the acquisition unit 30, the second end of the resistor R4 is connected to the positive electrode of the diode D1, and the negative electrode of the diode D1 is connected to the second end of the switch tube Q1.
[0036] In some embodiments, the current limiting unit 40 includes a resistor R6 and a capacitor C5. Specifically, a first end of the resistor R6 is connected to the driving unit 10, a second end of the resistor R6 is connected to a first end of the capacitor C5 and a control end of the switch tube Q1, and a second end of the capacitor C5 is connected to a third end of the switch tube Q1 and is grounded.
[0037] In some embodiments, the acquisition unit 30 includes a resistor R5 and a capacitor C4. Specifically, the first end of the resistor R5 is connected to the voltage divider 20, the second end of the resistor R5 is connected to the first end of the capacitor C4 and the drive unit 10, and the second end of the capacitor C4 is connected to the drive unit 10.
[0038] In order to more clearly illustrate the technical solution in the embodiment of the present invention, the following will be combined with the attached Figure 2 Make an introduction. Figure 2The chip used is TR21276, which is used to drive the switch tube Q1, and can be used for overcurrent protection by means of the tube voltage drop and related circuits when the switch tube Q1 is overcurrent. Among them, the VCC end of the chip U1 is the chip power supply end, the COM end of the chip U1 is the ground end, the IN end of the chip U1 is the PWM input end, the FLT end of the chip U1 is the overcurrent alarm end, the HO end of the chip U1 is the output end, the CS end of the chip U1 is the overcurrent detection end, the VB end of the chip U1 is the input end of the driving floating power supply, and the VS end of the chip U1 is the ground end of the driving floating power supply. Generally, a bootstrap capacitor C3 is connected between the VB end of the chip U1 and the VS end of the chip U1.
[0039] In practical applications, it is assumed that the current protection value of the designed overcurrent protection circuit is Iocp, and then the on-resistance Ron or on-voltage Vds of the drain-source when overcurrent is determined by consulting the data sheet of the switch tube Q1. The essence is to know the on-voltage Vds when overcurrent occurs. If only the on-resistance Ron is known, it can be multiplied by the current protection value Iocp. It is known that the input voltage of the VB terminal of the chip U1 is VB, then the typical output value of the voltage at the HO terminal of the chip U1 is Vho=VB-0.05. It is known that the on-voltage of the diode D1 is Vd, and the sum of the voltages of the resistors R3 and R4 can be determined by Vho-Vd-Vds. Suppose the current flowing through the two resistors at this time is Ir, and then by:
[0040] Vho-Vd-Vds=Ir(R3+R4) Formula 1
[0041] Ir*R4+Vd+Vds=CSV Formula 2
[0042] Wherein, R3 in Formula 1 is Figure 2 The resistance of resistors R3 and R4 is Figure 2 The resistance value of the resistor R4 is Figure 2 The resistance value of the resistor R4 in the middle, the CSV in formula 2 is the trigger voltage of the CS terminal of the chip U1, for example, the CSV of TR21276 is usually 1.8V.
[0043] By using the above formula, the appropriate resistance values of the resistor R3 and the resistor R4 can be determined during the research and development stage.
[0044] In this embodiment, when the switch tube Q1 is overcurrent, the voltage at the CS terminal of the chip U1 will detect a voltage higher than the trigger voltage of the CS terminal, and then immediately cut off the output of the HO terminal of the chip U1 and transmit a fault signal to the control device (such as MCU) through the FIT terminal until the next time the control device has input and the voltage at the CS terminal is lower than the trigger voltage of the CS terminal to return to normal.
[0045] The embodiment of the present application provides an overcurrent protection circuit 100, which includes a driving unit 10, a voltage dividing unit 20, a current limiting unit 40 and a collection unit 30. When the switch tube Q1 is turned on, the voltage dividing unit 20 divides the voltage at the second end of the switch tube Q1 to output the divided current to the collection unit 30; when the collection unit 30 receives the divided current, it converts the divided current into a collection current and outputs the collection current to the driving unit 10; when the collection current is greater than the first preset current, the driving unit 10 outputs a first control signal to the control end of the switch tube Q1 to turn off the switch tube Q1. When the current of the switch tube Q1 is too large, the switch tube Q1 can be controlled to be turned off to protect the circuit structure. The embodiment of the present application can realize overcurrent protection without a current sensor, improve the accuracy of overcurrent protection, shorten the response time, and reduce the area occupied by the protection circuit.
[0046] See also Figure 3 , Figure 3 It is a structural block diagram of a single-phase overcurrent protection circuit provided in an embodiment of the present application.
[0047] The embodiment of the present application also provides a single-phase overcurrent protection circuit 100, which includes two overcurrent protection circuits as above, and the two overcurrent protection circuits are respectively a first overcurrent protection circuit 101 and a second overcurrent protection circuit 201. Specifically, the single-phase overcurrent protection circuit 100 is connected to a single-phase bridge arm, and the single-phase bridge arm includes an upper switch tube Q1 and a lower switch tube Q2. The first overcurrent protection circuit 101 is connected to the upper switch tube Q1, and the second overcurrent protection circuit 201 is connected to the lower switch tube Q2. The third end of the upper switch tube Q1 is connected to the second end of the lower switch tube Q2, and the third end of the lower switch tube Q2 is grounded. Among them, the second end of the switch tube Q1 is also connected to a direct current power supply DC, and the direct current power supply DC supplies power to the switch tube Q1 and the switch tube Q2.
[0048] In some embodiments, the first overcurrent protection circuit 101 includes a first driving unit 11, a first voltage dividing unit 12, a first current limiting unit 14, and a first acquisition unit 13. Specifically, the first driving unit 11 is connected to the control end of the upper switch tube Q1 through the first current limiting unit 14, the first driving unit 11 is connected to the second end of the upper switch tube Q1 through the first voltage dividing unit 12, and the first driving unit 11 is also connected to the third end of the upper switch tube Q1. Among them, the first driving unit 11 is used to receive the first PWM signal, and output the first switch tube control signal to the control end of the upper switch tube Q1 through the first current limiting unit 14 according to the first PWM signal to control the on-off state of the upper switch tube Q1; the first voltage dividing unit 12 is used to divide the voltage at the second end of the upper switch tube Q1 when the upper switch tube Q1 is turned on, so as to output the first divided voltage current to the first collection unit 13; the first collection unit 13 is used to convert the first divided voltage current into a first collection current when receiving the first divided voltage current, and output the first collection current to the first driving unit 11; the first driving unit 11 is also used to receive the first collection current, and when the first collection current is greater than the second preset current, output the second control signal to the control end of the upper switch tube Q1 to turn off the upper switch tube Q1.
[0049] In some embodiments, the second overcurrent protection circuit 201 includes a second driving unit 21, a second voltage dividing unit 22, a second current limiting unit 24 and a second acquisition unit 24. Specifically, the second driving unit 21 is connected to the control end of the lower switch tube Q2 through the second current limiting unit 24, the second driving unit 21 is connected to the second end of the lower switch tube Q2 through the second voltage dividing unit 22, and the second driving unit 21 is also connected to the third end of the lower switch tube Q2. Among them, the second driving unit 21 is used to receive the second PWM signal, and output the second switch tube control signal to the control end of the lower switch tube Q2 through the second current limiting unit 24 according to the second PWM signal to control the on-off state of the lower switch tube Q2; the second voltage dividing unit 22 is used to divide the voltage of the second end of the lower switch tube Q2 when the lower switch tube Q2 is turned on, so as to output the second divided voltage current to the second collection unit 24; the second collection unit 24 is used to convert the second divided voltage current into a second collection current when receiving the second divided voltage current, and output the second collection current to the second driving unit 21; the second driving unit 21 is also used to receive the second collection current, and when the second collection current is greater than the third preset current, output the third control signal to the control end of the lower switch tube Q2 to turn off the lower switch tube Q2.
[0050] See also Figure 4 , Figure 4 It is a circuit structure schematic diagram of a single-phase overcurrent protection circuit provided in an embodiment of the present application.
[0051] The single-phase bridge arm includes an upper switch tube Q1 and a lower switch tube Q2, which are respectively protected from overcurrent by overcurrent protection circuits of the upper switch tube Q1 and the lower switch tube Q2. The specific principle can be referred to the overcurrent protection circuit of the above embodiment, which will not be repeated here.
[0052] The embodiment of the present application further provides a multi-phase overcurrent protection circuit, comprising at least two single-phase overcurrent protection circuits as above, wherein each of the at least two single-phase overcurrent protection circuits is connected to a single-phase bridge arm.
[0053] Each single-phase bridge arm includes an upper switch tube and a lower switch tube, and overcurrent protection is performed by means of overcurrent protection circuits of the upper switch tube and the lower switch tube respectively. The specific principle can be referred to the overcurrent protection circuit of the above embodiment, which will not be repeated here.
[0054] It should be noted that this circuit design is carried out on the circuit required by the motor controller as much as possible. For example, the sampling circuit is based on the three-phase inverter bridge arm circuit. The multi-phase overcurrent protection circuit in the embodiment of the present application can be based on the driving circuit of the three-phase inverter bridge arm circuit, and the protection can be completed by the hardware protection circuit in the driving circuit, and the protection process does not require software participation.
[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Based on the idea of the present application, the technical features in the above embodiments or different embodiments may also be combined, and there are many other changes in different aspects of the present application as described above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.
Claims
1. An overcurrent protection circuit, characterized in that: include: Driving unit, voltage dividing unit, current limiting unit and collection unit; The driving unit is connected to the control device, the driving unit is connected to the control end of the switch tube Q1 through the current limiting unit, the driving unit is connected to the second end of the switch tube Q1 through the voltage dividing unit, and the driving unit is also connected to the third end of the switch tube Q1; The driving unit is used to receive the PWM signal of the control device, and output a switch tube control signal to the control end of the switch tube Q1 through the current limiting unit according to the PWM signal to control the on / off state of the switch tube Q1; The voltage dividing unit is used to divide the voltage at the second end of the switch tube Q1 when the switch tube Q1 is turned on, so as to output a divided voltage current to the collection unit; The collection unit is used for converting the divided voltage current into a collection current when receiving the divided voltage current, and outputting the collection current to the driving unit; The driving unit is further configured to receive the collection current, and when the collection current is greater than a first preset current, output a first control signal to the control end of the switch tube Q1 to turn off the switch tube Q1.
2. The overcurrent protection circuit according to claim 1, characterized in that: The driving unit includes a chip U1, a capacitor C1, a capacitor C2, a capacitor C3, a diode D2, a resistor R2, and a resistor R7; The VCC terminal of the chip U1 is connected to the COM terminal of the chip U1 through the capacitor C1, the VCC terminal of the chip U1 is also connected to the first power supply, the COM terminal of the chip U1 is also connected to the positive electrode of the diode D2 and grounded, the IN terminal of the chip U1 is connected to the control device through the resistor R1, the FLT terminal of the chip U1 is connected to the control device through the resistor R2, the FIT terminal of the chip U1 is also grounded through the capacitor C2, the VB terminal of the chip U1 is connected to the VS terminal of the chip U1 through the capacitor C3, the VS terminal of the chip U1 is also connected to the negative electrode of the diode D2 and the first end of the resistor R7, the second end of the resistor R7 is connected to the third end of the switch tube Q1, the HO terminal of the chip U1 is connected to the voltage divider unit and the current limiting unit, and the CS terminal of the chip U1 is connected to the acquisition unit.
3. The overcurrent protection circuit according to claim 1, characterized in that: The voltage dividing unit includes a resistor R3, a resistor R4, and a diode D1; The first end of the resistor R3 is connected to the driving unit, the second end of the resistor R3 is connected to the first end of the resistor R4 and the acquisition unit, the second end of the resistor R4 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the second end of the switch tube Q1.
4. The overcurrent protection circuit according to claim 1, characterized in that: The current limiting unit includes a resistor R6 and a capacitor C5; The first end of the resistor R6 is connected to the driving unit, the second end of the resistor R6 is connected to the first end of the capacitor C5 and the control end of the switch tube Q1, and the second end of the capacitor C5 is connected to the third end of the switch tube Q1 and grounded.
5. The overcurrent protection circuit according to claim 1, characterized in that: The acquisition unit includes a resistor R5 and a capacitor C4; A first end of the resistor R5 is connected to the voltage dividing unit, a second end of the resistor R5 is connected to a first end of the capacitor C4 and the driving unit, and a second end of the capacitor C4 is connected to the driving unit.
6. A single-phase overcurrent protection circuit, characterized in that: The single-phase overcurrent protection circuit comprises two overcurrent protection circuits according to any one of claims 1 to 5, the two overcurrent protection circuits being respectively a first overcurrent protection circuit and a second overcurrent protection circuit; The single-phase overcurrent protection circuit is connected to the single-phase bridge arm, and the single-phase bridge arm includes an upper switch tube Q1 and a lower switch tube Q2. The first overcurrent protection circuit is connected to the upper switch tube Q1, and the second overcurrent protection circuit is connected to the lower switch tube Q2. The third end of the upper switch tube Q1 is connected to the second end of the lower switch tube Q2, and the third end of the lower switch tube Q2 is grounded.
7. The single-phase overcurrent protection circuit according to claim 6, characterized in that: The first overcurrent protection circuit includes a first driving unit, a first voltage dividing unit, a first current limiting unit and a first acquisition unit; The first driving unit is connected to the control end of the upper switch tube Q1 through the first current limiting unit, the first driving unit is connected to the second end of the upper switch tube Q1 through the first voltage dividing unit, and the first driving unit is also connected to the third end of the upper switch tube Q1; The first driving unit is used to receive a first PWM signal, and output a first switch control signal to the control end of the upper switch Q1 through the first current limiting unit according to the first PWM signal to control the on / off state of the upper switch Q1; The first voltage dividing unit is used for dividing the voltage at the second end of the upper switch tube Q1 when the upper switch tube Q1 is turned on, so as to output a first voltage-divided current to the first acquisition unit; The first acquisition unit is used for converting the first divided voltage current into a first acquisition current when receiving the first divided voltage current, and outputting the first acquisition current to the first driving unit; The first driving unit is further configured to receive the first collection current, and output a second control signal to the control end of the upper switch tube Q1 when the first collection current is greater than a second preset current, so as to turn off the upper switch tube Q1.
8. The single-phase overcurrent protection circuit according to claim 6, characterized in that: The second overcurrent protection circuit includes a second driving unit, a second voltage dividing unit, a second current limiting unit and a second acquisition unit; The second driving unit is connected to the control end of the lower switch tube Q2 through the second current limiting unit, the second driving unit is connected to the second end of the lower switch tube Q2 through the second voltage dividing unit, and the second driving unit is also connected to the third end of the lower switch tube Q2; The second driving unit is used to receive a second PWM signal, and output a second switch tube control signal to the control end of the lower switch tube Q2 through the second current limiting unit according to the second PWM signal to control the on / off state of the lower switch tube Q2; The second voltage dividing unit is used for dividing the voltage at the second end of the lower switch tube Q2 when the lower switch tube Q2 is turned on, so as to output a second voltage dividing current to the second collection unit; The second collection unit is used for converting the second divided voltage current into a second collection current when receiving the second divided voltage current, and outputting the second collection current to the second driving unit; The second driving unit is further configured to receive the second collection current, and output a third control signal to the control end of the lower switch tube Q2 when the second collection current is greater than a third preset current, so as to turn off the lower switch tube Q2.
9. A multi-phase overcurrent protection circuit, characterized in that: comprising at least two single-phase overcurrent protection circuits as claimed in claim 6; Each of the at least two single-phase overcurrent protection circuits is connected to a single-phase bridge arm.