Quick response protection circuit

Abstract

The utility model relates to a quick response protection circuit, which comprises a power supply, an input circuit, a comparator U1A, a comparator U1B, a first MOS (Metal Oxide Semiconductor) tube, a second MOS tube, a third MOS tube, a capacitor C1, a capacitor C2, a capacitor C3, an MCU (Microprogrammed Control Unit) control circuit and a driving control circuit, the input circuit is electrically connected with the negative electrode input end of the comparator U1B and the positive electrode input end of the comparator U1A, the output end of the comparator U1B and the output end of the comparator U1A are both electrically connected with the first MOS tube and the second MOS tube, the third MOS tube is electrically connected with the first MOS tube, the second MOS tube and the driving control circuit, and the driving control circuit is electrically connected with the third MOS tube. The MCU control circuit is electrically connected with the first MOS tube and the second MOS tube, current abnormity in the circuit is detected in time, when the current exceeds a preset value, the circuit can rapidly cut off or limit the current, and an inductance element or other circuit elements are prevented from being damaged due to overheating.

Description

Technical Field

[0001] This application relates to the field of circuit protection technology, and in particular to a fast-response protection circuit. Background Technology

[0002] For power electronic switching devices (such as MOSFETs, GTRs, and IGBTs), due to their low overcurrent tolerance, dedicated overcurrent protection circuits are required. These protection circuits need to complete overcurrent detection, signal transmission, and protection action instantaneously. However, in some extreme cases, they may not be able to completely prevent damage caused by overcurrent. For example, software-implemented overcurrent protection requires milliseconds, which is not fast enough. By the time protection is activated, the device may already be damaged. Although hardware protection has a fast response time, it may be prone to false alarms, limiting its application. Utility Model Content

[0003] In view of this, this application proposes a fast-response protection circuit.

[0004] According to one aspect of this application, a fast response protection circuit is provided, comprising: a power supply, an input circuit, comparators U1A and U1B, resistors R1, R2, R6, and R9, a first MOSFET, a second MOSFET, a third MOSFET, capacitors C1, C2, and C3, an MCU control circuit, and a drive control circuit.

[0005] The input circuit is an output signal, and the input circuit is electrically connected to the negative input terminal of the comparator U1B and the positive input terminal of the comparator U1A.

[0006] The output terminals of comparator U1B and comparator U1A are both electrically connected to the first MOS transistor and the second MOS transistor.

[0007] The third MOSFET is electrically connected to the first MOSFET, the second MOSFET and the drive control circuit, respectively, and the MCU control circuit is electrically connected to the first MOSFET and the second MOSFET.

[0008] The positive terminal of the power supply is electrically connected to resistors R1, R2, and R9, the positive input terminal of comparator U1B, and the negative input terminal of comparator U1A, respectively. The negative terminal is electrically connected to resistors C1, C2, and C3, respectively. Resistor R6 is grounded and electrically connected to the second MOSFET and the third MOSFET, respectively.

[0009] In one possible implementation, the gate of the first MOS transistor is electrically connected to the resistor R2, the output of the comparator U1B, and the output of the comparator U1A.

[0010] The drain of the first MOS transistor is electrically connected to the resistor R9;

[0011] The source of the first MOS transistor is electrically connected to the gate of the third MOS transistor and the MCU control circuit.

[0012] In one possible implementation, the drain of the second MOS transistor is electrically connected to the output terminals of the comparator U1A and the comparator U1B.

[0013] The gate of the second MOS transistor is electrically connected to the gate of the MCU control circuit and the gate of the third MOS transistor;

[0014] The source of the second MOSFET is grounded.

[0015] In one possible implementation, the gate of the third MOS transistor is electrically connected to the source of the first MOS transistor and the gate of the second MOS transistor.

[0016] The drain of the third MOS transistor is electrically connected to the drive control circuit;

[0017] The source of the third MOS transistor is grounded.

[0018] One possible implementation also includes: resistor R3;

[0019] The resistor R3 is connected in series between the comparator U1B and the gate of the first MOS transistor.

[0020] One possible implementation also includes: resistor R7;

[0021] The R7 resistor is connected in series with the MCU control circuit.

[0022] One possible implementation also includes: resistors R5 and R8;

[0023] The power supply, the resistor R1, and the positive input terminal of the comparator U1B are connected in series.

[0024] The power supply, resistor R1, resistor R5, resistor R8, and the negative input terminal of comparator U1A are connected in series.

[0025] In one possible implementation, the resistors R1, R5, and R8 have the same blocking effect.

[0026] In one possible implementation, the voltage of the input circuit is between 1 / 3 and 2 / 3 of the voltage of the power supply.

[0027] One possible implementation also includes: resistor R4;

[0028] The resistor R4 is connected in series with the input circuit.

[0029] The beneficial effects of the fast-response protection circuit in this application embodiment are as follows: Under normal conditions, the MCU control circuit is in a high-impedance state according to the default power-on configuration. When the input circuit voltage is within the set range, such as between 2 / 3 and 1 / 3 of the power supply voltage, the output voltages of comparators U1A and U1B are both high. The first MOSFET is cut off and not conducting. The gate voltages of the second and third MOSFETs are pulled to ground by resistor R6, and both are cut off. The voltage of the drive control circuit is determined by the drive control circuit, and the circuit works normally. When the input circuit voltage is higher than the input voltage of comparator U1B, the output voltage of comparator U1B is low, the first MOSFET is turned on, and the second MOSFET is easily turned on after the first MOSFET is turned on. The output voltage of comparator U1B is locked at a low level, and even if the input returns to normal, it remains low, maintaining the current protection state. The third MOSFET is turned on, the voltage of the drive control circuit remains low, and the output is cut off. In this way, this protection circuit can detect abnormal current in the circuit in a timely manner. When the current exceeds the preset value, the circuit will quickly cut off or limit the current to prevent inductors or other circuit components from being damaged due to overheating.

[0030] Other features and aspects of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0031] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this application together with the specification and serve to explain the principles of this application.

[0032] Figure 1 A schematic diagram of a fast response protection circuit according to an embodiment of this application is shown. Detailed Implementation

[0033] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0034] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0037] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0038] Figure 1 A schematic diagram of the main structure according to an embodiment of this application is shown. Figure 1As shown, the fast response protection circuit of this application embodiment includes: a power supply, an input circuit 10, comparators U1A15 and U1B14, resistors R119, R2223, R627, R925, a first MOSFET 16, a second MOSFET 17, a third MOSFET 18, capacitors C1, C2, and C3, an MCU control circuit 12, and a drive control circuit 11. The input circuit 10 is the output signal, and is electrically connected to the negative input terminal of comparator U1B14 and the positive input terminal of comparator U1A15. The output terminal of comparator U1B14 and the output terminal of comparator U1A15 are connected to the output terminal of comparator U1B15. The output terminals of A15 are all electrically connected to the first MOSFET 16 and the second MOSFET 17. The third MOSFET 18 is electrically connected to the first MOSFET 16, the second MOSFET 17 and the drive control circuit 11, respectively. The MCU control circuit 12 is electrically connected to the first MOSFET 16 and the second MOSFET 17. The positive terminal of the power supply is electrically connected to resistors R1 19, R2 23, R9 25, the positive input terminal of comparator U1B14 and the negative input terminal of comparator U1A15, respectively. The negative terminal is electrically connected to resistors C1, C2 and C3, respectively. Resistor R6 is grounded and electrically connected to the second MOSFET 17 and the third MOSFET 18, respectively.

[0039] In this specific embodiment, under normal conditions, the MCU control circuit 12 is in a high-impedance state according to the default power-on configuration. When the voltage of the input circuit 10 is within the set range, such as between 2 / 3 and 1 / 3 of the power supply voltage, the output voltages of comparators U1A15 and U1B14 are both high. The first MOSFET 16 is cut off and not conducting. The gate voltages of the second MOSFET 17 and the third MOSFET 18 are pulled to ground by resistor R6 27, and both are cut off. The voltage of the drive control circuit 11 is determined by the drive control circuit 11, and the circuit works normally. When the voltage of the input circuit 10 is higher than the input voltage of comparator U1B14, the output voltage of comparator U1B14 is low, the first MOSFET 16 is turned on, and the second MOSFET 17 is easily turned on after the first MOSFET 16 is turned on. The output voltage of comparator U1B14 is locked at a low level, and even if the input returns to the normal value, it remains low, maintaining the current protection state. The third MOSFET 18 is turned on, the voltage of the drive control circuit 11 remains low, and the output is cut off. In this way, the protection circuit can detect abnormal current in the circuit in a timely manner. When the current exceeds the preset value, the circuit will quickly cut off or limit the current to prevent the inductor or other circuit components from being damaged due to overheating.

[0040] In one specific embodiment, the gate of the first MOSFET 16 is electrically connected to resistor R2 23, the output of comparator U1B14, and the output of comparator U1A15. The drain of the first MOSFET 16 is electrically connected to resistor R9 25. The source of the first MOSFET 16 is electrically connected to the gate of the third MOSFET 18 and the MCU control circuit 12. Thus, when the output voltages of comparators U1A15 and U1B14 are high, the first MOSFET 16 is not turned on, and when the output voltages of comparators U1A15 and U1B14 are low, the first MOSFET 16 is turned on.

[0041] In one specific embodiment, the drain of the second MOSFET 17 is electrically connected to the output terminals of comparator U1A15 and comparator U1B14, the gate of the second MOSFET 17 is electrically connected to the gate of the MCU control circuit 12 and the third MOSFET 18, and the source of the second MOSFET 17 is grounded. When the first MOSFET 16 is turned on, the second MOSFET 17 is easily turned on, and when the first MOSFET 16 is not turned on, the gate voltage of the second MOSFET 17 is pulled to ground by resistor R6 27.

[0042] In one specific embodiment, the gate of the third MOSFET 18 is electrically connected to the source of the first MOSFET 16 and the gate of the second MOSFET 17, the drain of the third MOSFET 18 is electrically connected to the drive control circuit 11, and the source of the third MOSFET 18 is grounded. When the first MOSFET 16 is not turned on, the gate voltage of the third MOSFET 18 is pulled to ground by the resistor R6 27. When the output voltage of the comparator U1B14 is locked at a low level, the third MOSFET 18 is turned on, the drive control circuit 11 maintains a low level, and the output is cut off.

[0043] In one specific embodiment, it further includes: resistor R3 24, which is connected in series between comparator U1B14 and the gate of the first MOSFET 16. Resistor R3 24 is used to limit the current and protect the first MOSFET 16. When the comparator U1B14 outputs a signal to control the gate of the first MOSFET 16, resistor R3 24 can prevent excessive current from flowing into the gate instantaneously, thus avoiding damage to the first MOSFET 16 and playing the role of current limiting and protection.

[0044] In one specific embodiment, it further includes: resistor R7 26, which is connected in series with the MCU control circuit 12. Resistor R7 26 is used for current limiting, protecting the gate of the second MOSFET 17, preventing excessive current from damaging the second MOSFET 17, and ensuring the reliability and stability of the circuit.

[0045] In one specific embodiment, the circuit further includes: resistors R5 20 and R8 21; the power supply, resistor R1 19, and the positive input terminal of comparator U1B14 are connected in series; and the power supply, resistors R1 19, R5 20, R8 21, and the negative input terminal of comparator U1A15 are connected in series. Resistors R1 19, R5 20, and R8 21 are used for voltage division to provide a reference voltage for comparator U1A15 or comparator U1B14. In the input circuit 10, together with capacitors C1 and C2, they form a filtering or biasing circuit to help stabilize the level of the input signal, ensuring that the signal input to the comparator is within a suitable range for accurate comparison and processing.

[0046] Among them, resistors R1 (19), R5 (20), and R8 (21) have the same blocking effect.

[0047] The voltage of the input circuit 10 is between 1 / 3 and 2 / 3 of the power supply voltage.

[0048] In one specific embodiment, it further includes: resistor R5 22, which is connected in series with the input circuit 10. Resistor R5 22 is used to appropriately attenuate or limit the current of the input circuit 10, preventing excessive current from flowing into subsequent circuits and playing a protective role. It may also participate in the signal conditioning process to match the impedance of the input signal with that of the subsequent circuits, ensuring effective signal transmission and processing.

[0049] In this specific embodiment, resistor R6 27 is used for voltage division or current limiting. In the microcontroller IC control circuit, it may work with other components to provide the microcontroller with a suitable control signal level, or to limit the current output from the microcontroller to other circuits, thus protecting the microcontroller's output port.

[0050] In this specific embodiment, R9 is used for pull-up or pull-down to ensure that the signal level in the drive control circuit 11 is stable at an appropriate level.

[0051] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A fast-response protection circuit, characterized in that, include: Power supply, input circuit, comparator U1A, comparator U1B, resistor R1, resistor R2, resistor R6, resistor R9, first MOSFET, second MOSFET, third MOSFET, capacitor C1, capacitor C2, capacitor C3, MCU control circuit and drive control circuit; The input circuit is an output signal, and the input circuit is electrically connected to the negative input terminal of the comparator U1B and the positive input terminal of the comparator U1A. The output terminals of comparator U1B and comparator U1A are both electrically connected to the first MOS transistor and the second MOS transistor. The third MOSFET is electrically connected to the first MOSFET, the second MOSFET and the drive control circuit, respectively, and the MCU control circuit is electrically connected to the first MOSFET and the second MOSFET. The positive terminal of the power supply is electrically connected to resistors R1, R2, and R9, the positive input terminal of comparator U1B, and the negative input terminal of comparator U1A, respectively. The negative terminal is electrically connected to resistors C1, C2, and C3, respectively. Resistor R6 is grounded and electrically connected to the second MOSFET and the third MOSFET, respectively.

2. The fast response protection circuit according to claim 1, characterized in that, The gate of the first MOS transistor is electrically connected to the resistor R2, the output terminal of the comparator U1B, and the output terminal of the comparator U1A; The drain of the first MOS transistor is electrically connected to the resistor R9; The source of the first MOS transistor is electrically connected to the gate of the third MOS transistor and the MCU control circuit.

3. The fast response protection circuit according to claim 1, characterized in that, The drain of the second MOS transistor is electrically connected to the output terminals of comparator U1A and comparator U1B. The gate of the second MOS transistor is electrically connected to the gate of the MCU control circuit and the gate of the third MOS transistor; The source of the second MOSFET is grounded.

4. The fast response protection circuit according to claim 1, characterized in that, The gate of the third MOS transistor is electrically connected to the source of the first MOS transistor and the gate of the second MOS transistor. The drain of the third MOS transistor is electrically connected to the drive control circuit; The source of the third MOS transistor is grounded.

5. The fast response protection circuit according to any one of claims 1-4, characterized in that, Also includes: R3 resistor; The resistor R3 is connected in series between the comparator U1B and the gate of the first MOS transistor.

6. The fast response protection circuit according to any one of claims 1-4, characterized in that, Also includes: R7 resistor; The R7 resistor is connected in series with the MCU control circuit.

7. The fast-response protection circuit according to any one of claims 1-4, characterized in that, Also includes: R5 and R8 resistors; The power supply, the resistor R1, and the positive input terminal of the comparator U1B are connected in series. The power supply, resistor R1, resistor R5, resistor R8, and the negative input terminal of comparator U1A are connected in series.

8. The fast response protection circuit according to claim 7, characterized in that, The resistors R1, R5, and R8 have the same blocking effect.

9. The fast response protection circuit according to claim 1, characterized in that, The voltage of the input circuit is between 1 / 3 and 2 / 3 of the voltage of the power supply.

10. The fast-response protection circuit according to claim 1, characterized in that, Also includes: R4 resistor; The resistor R4 is connected in series with the input circuit.

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