Overcurrent protection device and equipment

Abstract

The utility model discloses an overcurrent protection device and equipment, and the device comprises a power supply on-off circuit which comprises a first on-off sub-circuit; a first end of the current detection circuit is connected with a system power supply of the to-be-protected system, a second end of the current detection circuit is connected with a first end of the first on-off sub-circuit, a second end of the first on-off sub-circuit is connected with a load of the to-be-protected system, and the current detection circuit is used for detecting system current of the to-be-protected system. The system current is converted into system voltage; the first input end of the overcurrent holding circuit is connected with the output end of the current detection circuit, the second input end of the overcurrent holding circuit is connected with target reference voltage, the output end of the overcurrent holding circuit is connected with the control end of the first on-off sub-circuit, and the overcurrent holding circuit is used for continuously outputting high level when the system voltage is larger than the target reference voltage. And controlling to disconnect the first on-off sub-circuit so as to disconnect the connection between the system power supply and the load.

Description

Technical Field

[0001] The utility model relates to the technical field of overcurrent protection, in particular to an overcurrent protection device and equipment. Background Art

[0002] An overcurrent condition occurs when the current exceeds the maximum allowed by a device or system. Overcurrent can cause heating, damage, or performance degradation. For example, in a household circuit, overcurrent can cause a fuse to blow or a circuit breaker to trip. In critical facilities like industrial production lines or data centers, overcurrent can even cause permanent damage to equipment, impacting production or business operations. Therefore, preventing and addressing overcurrent is crucial. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, one purpose of the present invention is to provide an overcurrent protection device that effectively prevents overcurrent from occurring in the system and has the advantages of flexible adjustment and wide applicability.

[0004] The second purpose of the present invention is to provide a device.

[0005] To achieve the above-mentioned purpose, the first embodiment of the present invention proposes an overcurrent protection device, which includes: a power on-off circuit, which includes a first on-off sub-circuit; a current detection circuit, wherein the first end of the current detection circuit is connected to the system power supply of the system to be protected, the second end of the current detection circuit is connected to the first end of the first on-off sub-circuit, and the second end of the first on-off sub-circuit is connected to the load of the system to be protected, and is used to detect the system current of the system to be protected and convert the system current into a system voltage; an overcurrent holding circuit, wherein the first input end of the overcurrent holding circuit is connected to the output end of the current detection circuit, the second input end of the overcurrent holding circuit is connected to the target reference voltage, and the output end of the overcurrent holding circuit is connected to the control end of the first on-off sub-circuit, and is used to continuously output a high level when the system voltage is greater than the target reference voltage, and control the disconnection of the first on-off sub-circuit to disconnect the connection between the system power supply and the load.

[0006] According to the overcurrent protection device of the embodiment of the present invention, the overcurrent holding circuit is used to compare the system voltage output by the current detection circuit with the target reference voltage. When the system voltage is greater than the target reference voltage, the overcurrent protection device continuously outputs a high level and disconnects the first on-off sub-circuit to disconnect the connection between the system power supply and the load, thereby effectively preventing overcurrent from occurring in the system. The device has the advantages of flexible adjustment and wide applicability.

[0007] In addition, the overcurrent protection device proposed in the above embodiment of the present invention may also have the following additional technical features:

[0008] According to one embodiment of the present utility model, the device also includes: the single-chip microcomputer, which is used to output a PWM signal with a target duty cycle; a threshold adjustment circuit, wherein the first end of the threshold adjustment circuit is connected to the PWM pin end of the single-chip microcomputer, and the second end of the threshold adjustment circuit is connected to the second input end of the overcurrent holding circuit, and is used to output the target reference voltage according to the PWM signal with the target duty cycle.

[0009] According to one embodiment of the present utility model, the power on-off circuit includes a second on-off sub-circuit, a first end of the second on-off sub-circuit is connected to the first end of the current detection circuit, a second end of the second on-off sub-circuit is grounded, a control end of the second on-off sub-circuit is connected to the IOC pin of the microcontroller, and an output end of the overcurrent holding circuit is connected to the PP7 pin of the microcontroller. The microcontroller is configured to control the disconnection of the second on-off sub-circuit when it detects that the overcurrent holding circuit 30 is not in a working state, so as to put the system to be protected into a low power consumption state.

[0010] According to one embodiment of the present utility model, the current detection circuit includes a first resistor, a second resistor, a first capacitor, a third resistor, a current sensor, a fourth resistor, a first voltage supply and a second capacitor, the first end of the first resistor is connected to the first end of the current detection circuit, the second end of the first resistor is connected to the second end of the current detection circuit, the first end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the first end of the third resistor, the second end of the third resistor is connected to the second end of the first resistor, the second end of the second resistor is connected to the VIN+ end of the current sensor, the first end of the third resistor is connected to the VIN- end of the current sensor, the GND end of the current sensor is grounded, the power supply end of the current sensor is connected to the first voltage supply through the fourth resistor, the power supply end of the current sensor is grounded through the second capacitor, and the output end of the current sensor is connected to the output end of the current detection circuit.

[0011] According to one embodiment of the present utility model, the overcurrent holding circuit includes a fifth resistor, a comparator, a second voltage supply, a third capacitor, a diode and a sixth resistor, the first end of the fifth resistor is connected to the first input end of the overcurrent holding circuit, the second end of the fifth resistor is connected to the positive phase end of the comparator, the negative phase end of the comparator is connected to the second input end of the overcurrent holding circuit, the power supply end of the comparator is connected to the second voltage supply, the power supply end of the comparator is grounded through the third capacitor, the GND end of the comparator is grounded, the output end of the comparator is connected to the negative electrode of the diode to form a first node, the first node is connected to the output end of the overcurrent holding circuit, the positive electrode of the diode is connected to the first end of the sixth resistor, and the second end of the sixth resistor is connected to the negative phase end of the comparator.

[0012] According to one embodiment of the present utility model, the overcurrent holding circuit further includes a first NMOS transistor and a seventh resistor, the drain of the first NMOS transistor is connected to the non-inverting terminal of the comparator, the source of the first NMOS transistor is grounded, and the gate of the NMOS transistor is connected to the PP1 pin of the microcontroller through the seventh resistor; the microcontroller is configured to input a high level to the first NMOS transistor after the overcurrent holding circuit outputs a high level for a preset time, thereby controlling the overcurrent holding circuit to output a low level.

[0013] According to one embodiment of the present utility model, the first on-off sub-circuit includes a PMOS tube and an eighth resistor, the source of the PMOS tube is connected to the first end of the first on-off sub-circuit, the drain of the PMOS tube is connected to the second end of the first on-off sub-circuit, and the gate of the PMOS tube is connected to the control end of the first on-off sub-circuit through the eighth resistor.

[0014] According to one embodiment of the present utility model, the second on-off sub-circuit further includes a ninth resistor, a tenth resistor, a second NMOS transistor, and an eleventh resistor. The first end of the ninth resistor is connected to the first end of the second on-off sub-circuit, the second end of the ninth resistor is connected to the base of the PMOS transistor, the second end of the ninth resistor is connected to the first end of the tenth resistor, the second end of the tenth resistor is connected to the drain of the second NMOS transistor, the source of the second NMOS transistor is grounded, the gate of the second NMOS transistor is connected to the first end of the eleventh resistor, and the second end of the eleventh resistor is connected to the second control input end of the on-off control circuit.

[0015] According to one embodiment of the present utility model, the threshold adjustment circuit includes a twelfth resistor, a fourth capacitor, an operational amplifier and a third power supply, the first end of the twelfth resistor is connected to the first end of the threshold adjustment circuit, the second end of the twelfth resistor is connected to the first end of the fourth capacitor, and forms a second node, the second end of the fourth capacitor is grounded, the second node is connected to the positive phase terminal of the operational amplifier, the output end of the operational amplifier is connected to the second end of the threshold adjustment circuit, the output end of the operational amplifier is connected to the negative phase terminal of the operational amplifier, and the ground end of the operational amplifier is grounded.

[0016] To achieve the above-mentioned purpose, a second embodiment of the present invention proposes a device, including the overcurrent protection device proposed in the first embodiment of the present invention.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of an overcurrent protection device according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of a current detection circuit and a power on / off circuit according to an embodiment of the present invention;

[0020] Figure 3 This is a partial pin diagram of a single chip microcomputer according to an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of an overcurrent holding circuit according to an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of a threshold adjustment circuit according to an embodiment of the present invention;

[0023] Figure 6 It is a schematic diagram of a device according to an embodiment of the present invention.

[0024] Reference numerals:

[0025] 10. Power on / off circuit; 20. Current detection circuit; 30. Overcurrent holding circuit; 40. Single-chip microcomputer; 50. Threshold adjustment circuit; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; R9, ninth resistor; R10, tenth resistor; R11, eleventh resistor; R12, twelfth resistor; C1, first capacitor; C2, second capacitor; C3, third capacitor; C4, fourth capacitor; D1, diode; Q1, first NMOS transistor; Q2, PMOS transistor; Q3, second NMOS transistor; A1, current sensor; U1, comparator; U2, operational amplifier; 1000, equipment; 100, overcurrent protection device. DETAILED DESCRIPTION

[0026] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] The overcurrent protection device and equipment of the embodiment of the utility model are described in detail below with reference to the accompanying drawings and specific implementation methods.

[0028] Figure 1 This is a schematic diagram of an overcurrent protection device according to an embodiment of the present invention. Figure 1 As shown, the overcurrent protection device may include:

[0029] The power on-off circuit 10 includes a first on-off sub-circuit;

[0030] a current detection circuit 20, wherein a first end of the current detection circuit 20 is connected to a system power supply of the system to be protected, a second end of the current detection circuit 20 is connected to a first end of the first on-off subcircuit, and a second end of the first on-off subcircuit is connected to a load of the system to be protected, and is configured to detect a system current of the system to be protected and convert the system current into a system voltage;

[0031] The overcurrent holding circuit 30 has a first input connected to the output of the current detection circuit 20, a second input connected to the target reference voltage, and an output connected to the control of the first on-off sub-circuit. The overcurrent holding circuit 30 is configured to continuously output a high level when the system voltage is greater than the target reference voltage, thereby controlling the disconnection of the first on-off sub-circuit to disconnect the system power supply from the load.

[0032] In the embodiment of the utility model, the system power supply of the system to be protected and the load are connected via a first on-off sub-circuit.

[0033] To prevent overcurrent in the protected system, the current detection circuit 20 of this embodiment is provided in the first on / off subcircuit. It detects the system current of the protected system and converts the detected system current into a system voltage. An overcurrent holding circuit 30 determines whether the system voltage is greater than a target reference voltage.

[0034] It should be noted that if the system voltage is less than or equal to the target reference voltage, it means that the system to be protected does not have an overcurrent phenomenon. If the system voltage is greater than the target reference voltage, it means that the system to be protected has an overcurrent phenomenon.

[0035] Therefore, when the overcurrent holding circuit 30 determines that the system voltage is greater than the target reference voltage, the overcurrent holding circuit 30 continuously outputs a high level, controls the disconnection of the first on-off sub-circuit, and keeps the first on-off sub-circuit in an off state, thereby disconnecting the connection between the system power supply and the load while preventing the system to be protected from frequent switching on and off and damaging the device.

[0036] In one embodiment of the present invention, Figure 2 As shown, the current detection circuit 20 includes a first resistor R1, a second resistor R2, a first capacitor C1, a third resistor R3, a current sensor A1, a fourth resistor R4, a first voltage supply, and a second capacitor C2. The first end of the first resistor R1 is connected to the first end of the current detection circuit 20, the second end of the first resistor R1 is connected to the second end of the current detection circuit 20, the first end of the first resistor R1 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the first end of the first capacitor C1, the second end of the first capacitor C1 is connected to the first end of the third resistor R3, the second end of the third resistor R3 is connected to the second end of the first resistor R1, the second end of the second resistor R2 is connected to the VIN+ terminal of the current sensor A1, the first end of the third resistor R3 is connected to the VIN- terminal of the current sensor A1, the GND terminal of the current sensor A1 is grounded, the power supply terminal of the current sensor A1 is connected to the first voltage supply through the fourth resistor R4, the power supply terminal of the current sensor A1 is grounded through the second capacitor C2, and the output terminal of the current sensor A1 is connected to the output terminal of the current detection circuit 20.

[0037] Specifically, the first resistor R1 is a current-sense resistor, which is connected between the system power supply and the first on-off subcircuit. The current sensor A1 detects the current passing through the first resistor R1 to determine the system current, and converts the system current into a voltage signal to obtain the system voltage.

[0038] In one embodiment of the present invention, the current sensor A1 may be a 200mΩ current sensor. Specific implementations include the INA193 current sensor.

[0039] In one embodiment of the present invention, Figure 2 As shown, the first on-off sub-circuit includes a PMOS transistor Q2 and an eighth resistor R8. The source of the PMOS transistor Q2 is connected to the first end of the first on-off sub-circuit, the drain of the PMOS transistor Q2 is connected to the second end of the first on-off sub-circuit, and the gate of the PMOS transistor Q2 is connected to the control end of the first on-off sub-circuit through the eighth resistor R8.

[0040] Specifically, the first on-off sub-circuit uses a PMOS transistor, and the on-off control of the first on-off sub-circuit is achieved by controlling the on-off of the PMOS transistor.

[0041] In one embodiment of the present invention, Figure 4 As shown, the overcurrent holding circuit 30 includes a fifth resistor R5, a comparator U1, a second voltage supply, a third capacitor C3, a diode D1 and a sixth resistor R6. The first end of the fifth resistor R5 is connected to the first input end of the overcurrent holding circuit 30, the second end of the fifth resistor R5 is connected to the positive phase end of the comparator U1, the negative phase end of the comparator U1 is connected to the second input end of the overcurrent holding circuit 30, the power supply end of the comparator U1 is connected to the second voltage supply, the power supply end of the comparator U1 is grounded through the third capacitor C3, the GND end of the comparator U1 is grounded, the output end of the comparator U1 is connected to the cathode of the diode D1, and form a first node, which is connected to the output end of the overcurrent holding circuit 30, the anode of the diode D1 is connected to the first end of the sixth resistor R6, and the second end of the sixth resistor R6 is connected to the negative phase end of the comparator U1.

[0042] Specifically, the positive terminal of comparator U1 is connected to the system voltage, and the negative terminal of comparator U1 is connected to the target reference voltage (VREF). If the system voltage is less than or equal to the target reference voltage, comparator U1 outputs a low level, turning on PMOS transistor Q2. If the system voltage is greater than the target reference voltage, comparator U1 is triggered to output a high level. The high level output of comparator U1 controls PMOS transistor Q2 to turn off, thereby disconnecting the system power supply from the load.

[0043] The diode D1 and the sixth resistor R6 in the overcurrent holding circuit 30 of the embodiment of the present invention form a feedback loop, so that the comparator U1 can maintain a high level output after outputting a high level, preventing the level output by the overcurrent holding circuit 30 from being frequently raised or lowered, thereby damaging the device.

[0044] In practice, the comparator U1 may be an ALD2301 comparator.

[0045] It should be noted that Figure 2 The ICS terminal of the current detection circuit 20 outputs Figure 4 The ICS terminal in the overcurrent holding circuit 30 is connected.

[0046] In one embodiment of the present invention, Figure 4 As shown, the overcurrent protection device further includes a single-chip microcomputer 40, and the overcurrent holding circuit 30 further includes a first NMOS transistor Q1 and a seventh resistor R7. The drain of the first NMOS transistor Q1 is connected to the non-inverting terminal of the comparator U1, the source of the first NMOS transistor Q1 is grounded, and the gate of the first NMOS transistor Q1 is connected to the PP1 pin of the single-chip microcomputer 40 through the seventh resistor R7.

[0047] The single chip microcomputer 40 is used to input a high level to the first NMOS transistor Q1 after the overcurrent holding circuit 30 outputs a high level for a preset time, so as to control the overcurrent holding circuit 30 to output a low level.

[0048] Specifically, the Self_Rec signal is a high level output by the microcontroller 40. After the overcurrent holding circuit 30 outputs a high level for a preset time, the microcontroller 40 outputs the Self_Rec signal, turning on the first NMOS transistor Q1. Turning on the first NMOS transistor Q1 releases the high level at the non-inverting terminal of the comparator U1 through the DS stage of the first NMOS transistor Q1, thereby causing the negative input pin of the comparator U1 to have a higher level than the positive input pin. The Ics_Int signal output by the comparator U1 then becomes low, unlocking the overcurrent holding circuit 30.

[0049] In this embodiment of the present invention, the interval of the Self_Rec signal output by the microcontroller 40 can be controlled. After the overcurrent holding circuit 30 outputs a high level for a preset period of time, the overcurrent holding circuit 30 is controlled to output a low level, thereby unlocking the overcurrent holding circuit 30. Furthermore, the number of times the microcontroller 40 outputs the Self_Rec signal can be set. After the microcontroller 40 outputs the Self_Rec signal for more than a preset number of times, the Self_Rec signal can be permanently turned off to prevent the protected system from being damaged by frequent disconnection.

[0050] In one embodiment of the present invention, Figure 1 and Figure 3 As shown, the overcurrent protection device also includes:

[0051] The single chip microcomputer 40 is used to output a PWM signal with a target duty cycle;

[0052] The threshold adjustment circuit 50 has a first end connected to the PWM pin of the single-chip microcomputer 40, and a second end connected to the second input of the overcurrent holding circuit 30, and is used to output a target reference voltage according to a PWM signal of a target duty cycle.

[0053] To expand the scope of application of the overcurrent protection device 100 of the present embodiment, the present embodiment connects the second input terminal of the overcurrent holding circuit 30 to the threshold adjustment circuit 50, and utilizes the single-chip microcomputer 40 to adjust the target reference voltage output by the threshold adjustment circuit 50, thereby adjusting the target reference voltage connected to the second input terminal of the overcurrent holding circuit 30. This allows the overcurrent protection device 100 of the present embodiment to be applicable to various instruments and equipment. It should be noted that the target reference voltage can be set according to the actual needs of the instrument or equipment.

[0054] Specifically, the duty cycle of the PWM (Pulse Width Modulation) signal output by the single-chip microcomputer 40 is controlled to adjust the target reference voltage output by the threshold adjustment circuit 50. The duty cycle refers to the ratio of the duration of the high level of the signal within one cycle to the total cycle time. The greater the duty cycle of the PWM signal output by the single-chip microcomputer 40, the greater the target reference voltage output by the threshold adjustment circuit 50. The smaller the duty cycle of the PWM signal output by the single-chip microcomputer 40, the smaller the target reference voltage output by the threshold adjustment circuit 50. The duty cycle of the PWM signal output by the single-chip microcomputer 40 can be adjusted according to the target reference voltage so that the target reference voltage output by the threshold adjustment circuit 50 is within the target reference voltage range.

[0055] In one embodiment of the present invention, Figure 5 As shown, the threshold adjustment circuit 50 includes a twelfth resistor R12, a fourth capacitor C4, an operational amplifier U2 and a third power supply. The first end of the twelfth resistor R12 is connected to the first end of the threshold adjustment circuit 50, the second end of the twelfth resistor R12 is connected to the first end of the fourth capacitor C4, and forms a second node. The second end of the fourth capacitor C4 is grounded, and the second node is connected to the positive phase terminal of the operational amplifier U2. The output end of the operational amplifier U2 is connected to the second end of the threshold adjustment circuit 50, the output end of the operational amplifier U2 is connected to the negative phase terminal of the operational amplifier U2, and the ground end of the operational amplifier U2 is grounded.

[0056] The threshold adjustment circuit 50 in the embodiment of the present invention can output a target reference voltage with high output impedance.

[0057] Specifically, the PWM signal output by the single chip microcomputer 40 passes through the RC filter circuit (the twelfth resistor R12 and the fourth capacitor C4) and the operational amplifier (operational amplifier U2) in the threshold adjustment circuit 50, and outputs a target reference voltage (VREF) with high output impedance.

[0058] In one embodiment of the present invention, Figure 2 and Figure 3As shown, the power on-off circuit 10 includes a second on-off sub-circuit, a first end of the second on-off sub-circuit is connected to the first end of the current detection circuit 20, a second end of the second on-off sub-circuit is grounded, a control end of the second on-off sub-circuit is connected to the IOC pin of the microcontroller 40, and an output end of the overcurrent holding circuit 30 is connected to the PP7 pin of the microcontroller 40. The microcontroller 40 is configured to control the disconnection of the second on-off sub-circuit when detecting that the overcurrent holding circuit 30 is not in an operating state, so as to put the system to be protected into a low power consumption state.

[0059] Specifically, the output of the overcurrent holding circuit 30 (the Ics_Int signal) is connected to the PP7 pin of the microcontroller 40. When the microcontroller 40 detects that there is no current input to the positive-phase terminal of the overcurrent holding circuit 30, or that the current input is less than a preset threshold, it determines that the overcurrent holding circuit 30 is not in operation. In this case, the microcontroller 40 controls the disconnection of the second on / off subcircuit, thereby placing the protected system in a low-power state.

[0060] In one embodiment of the present invention, Figure 2 As shown, the second on-off sub-circuit further includes a ninth resistor R9, a tenth resistor R10, a second NMOS transistor Q3, and an eleventh resistor R11. The first end of the ninth resistor R9 is connected to the first end of the second on-off sub-circuit, the second end of the ninth resistor R9 is connected to the base of the PMOS transistor, the second end of the ninth resistor R9 is connected to the first end of the tenth resistor R10, the second end of the tenth resistor R10 is connected to the drain of the second NMOS transistor Q3, the source of the second NMOS transistor Q3 is grounded, the gate of the second NMOS transistor Q3 is connected to the first end of the eleventh resistor R11, and the second end of the eleventh resistor R11 is connected to the control end of the second on-off sub-circuit.

[0061] Specifically, the DRV_CTL signal is a control signal output by the single-chip microcomputer 40. The DRV_CTL signal is connected to the control end of the second on-off sub-circuit. When the single-chip microcomputer 40 detects that the overcurrent holding circuit 30 is not in a working state, it controls the second NMOS tube Q3 to be disconnected, thereby realizing switch control of the power supply to the rear-end load, so that the protected system can be used with low power consumption.

[0062] The overcurrent protection device of the embodiment of the present utility model detects the system current through the current detection circuit and the current detection resistor, and converts the detected system current into a voltage signal, which is input to the positive input terminal of the comparator. The duty cycle of the output PWM signal is controlled by the single-chip microcomputer to adjust the size of the target reference voltage input to the negative input terminal of the comparator. The output terminal of the comparator is output to the control terminal of the first on-off sub-circuit on one path, and is fed back to the positive terminal of the input comparator through the diode on the other path, and then to the ground through the first NMOS tube Q1 to control the self-locking state. The power on-off circuit 10 is controlled by the overcurrent protection signal on one path and the single-chip microcomputer signal on the other path. By combining the on-off and self-locking states of the power supply, the triggering, protection, release and other state management of the system overcurrent protection are realized.

[0063] The utility model provides a device.

[0064] Figure 6 This is a schematic diagram of an embodiment of the present invention. Figure 6 As shown, the device 1000 includes the overcurrent protection device 100 as described above.

[0065] The device of the embodiment of the utility model utilizes the overcurrent protection device to perform overcurrent protection on the device, thereby achieving safety protection of the device system power supply and the device.

[0066] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0067] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0068] 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 the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0069] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0070] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0071] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An overcurrent protection device, characterized in that: The device comprises: A power on-off circuit, the power on-off circuit comprising a first on-off sub-circuit; a current detection circuit, wherein a first end of the current detection circuit is connected to a system power supply of the system to be protected, a second end of the current detection circuit is connected to a first end of the first on-off subcircuit, and a second end of the first on-off subcircuit is connected to a load of the system to be protected, and is configured to detect a system current of the system to be protected and convert the system current into a system voltage; An overcurrent holding circuit, wherein a first input terminal of the overcurrent holding circuit is connected to the output terminal of the current detection circuit, a second input terminal of the overcurrent holding circuit is connected to a target reference voltage, and an output terminal of the overcurrent holding circuit is connected to the control terminal of the first on-off sub-circuit, and is used to continuously output a high level when the system voltage is greater than the target reference voltage, thereby controlling the disconnection of the first on-off sub-circuit to disconnect the connection between the system power supply and the load.

2. The overcurrent protection device according to claim 1, characterized in that: The device further comprises: A single-chip microcomputer for outputting a PWM signal with a target duty cycle; A threshold adjustment circuit, wherein the first end of the threshold adjustment circuit is connected to the PWM pin end of the single-chip microcomputer, and the second end of the threshold adjustment circuit is connected to the second input end of the overcurrent holding circuit, and is used to output the target reference voltage according to the PWM signal of the target duty cycle.

3. The overcurrent protection device according to claim 2, characterized in that: The power on-off circuit comprises a second on-off subcircuit, a first end of the second on-off subcircuit is connected to the first end of the current detection circuit, a second end of the second on-off subcircuit is grounded, a control end of the second on-off subcircuit is connected to the IOC pin of the single-chip microcomputer, and an output end of the overcurrent holding circuit is connected to the PP7 pin of the single-chip microcomputer. The single-chip microcomputer is used to control the disconnection of the second on-off subcircuit when detecting that the overcurrent holding circuit (30) is not in an operating state, so as to put the system to be protected into a low power consumption state.

4. The overcurrent protection device according to claim 1, characterized in that: The current detection circuit includes a first resistor, a second resistor, a first capacitor, a third resistor, a current sensor, a fourth resistor, a first voltage supply, and a second capacitor. The first end of the first resistor is connected to the first end of the current detection circuit, the second end of the first resistor is connected to the second end of the current detection circuit, the first end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the first end of the third resistor, the second end of the third resistor is connected to the second end of the first resistor, the second end of the second resistor is connected to the VIN+ end of the current sensor, the first end of the third resistor is connected to the VIN- end of the current sensor, the GND end of the current sensor is grounded, the power supply end of the current sensor is connected to the first voltage supply through the fourth resistor, the power supply end of the current sensor is grounded through the second capacitor, and the output end of the current sensor is connected to the output end of the current detection circuit.

5. The overcurrent protection device according to claim 1, characterized in that: The overcurrent holding circuit includes a fifth resistor, a comparator, a second voltage supply, a third capacitor, a diode and a sixth resistor, wherein the first end of the fifth resistor is connected to the first input end of the overcurrent holding circuit, the second end of the fifth resistor is connected to the positive phase end of the comparator, the negative phase end of the comparator is connected to the second input end of the overcurrent holding circuit, the power supply end of the comparator is connected to the second voltage supply, the power supply end of the comparator is grounded through the third capacitor, the GND end of the comparator is grounded, the output end of the comparator is connected to the negative electrode of the diode to form a first node, the first node is connected to the output end of the overcurrent holding circuit, the positive electrode of the diode is connected to the first end of the sixth resistor, and the second end of the sixth resistor is connected to the negative phase end of the comparator.

6. The overcurrent protection device according to claim 5, characterized in that: The overcurrent holding circuit further includes a first NMOS transistor and a seventh resistor, wherein the drain of the first NMOS transistor is connected to the non-inverting terminal of the comparator, the source of the first NMOS transistor is grounded, and the gate of the NMOS transistor is connected to the PP1 pin of the microcontroller through the seventh resistor; The single chip microcomputer is used to input a high level to the first NMOS transistor after the overcurrent holding circuit outputs a high level for a preset time, so as to control the overcurrent holding circuit to output a low level.

7. The overcurrent protection device according to claim 1, characterized in that: The first on-off sub-circuit includes a PMOS transistor and an eighth resistor, the source of the PMOS transistor is connected to the first end of the first on-off sub-circuit, the drain of the PMOS transistor is connected to the second end of the first on-off sub-circuit, and the gate of the PMOS transistor is connected to the control end of the first on-off sub-circuit through the eighth resistor.

8. The overcurrent protection device according to claim 3, characterized in that: The second on-off sub-circuit further includes a ninth resistor, a tenth resistor, a second NMOS transistor, and an eleventh resistor. The first end of the ninth resistor is connected to the first end of the second on-off sub-circuit, the second end of the ninth resistor is connected to the base of the PMOS transistor, the second end of the ninth resistor is connected to the first end of the tenth resistor, the second end of the tenth resistor is connected to the drain of the second NMOS transistor, the source of the second NMOS transistor is grounded, the gate of the second NMOS transistor is connected to the first end of the eleventh resistor, and the second end of the eleventh resistor is connected to the second control input end of the on-off control circuit.

9. The overcurrent protection device according to claim 2, characterized in that: The threshold adjustment circuit includes a twelfth resistor, a fourth capacitor, an operational amplifier and a third power supply. The first end of the twelfth resistor is connected to the first end of the threshold adjustment circuit, the second end of the twelfth resistor is connected to the first end of the fourth capacitor, and forms a second node. The second end of the fourth capacitor is grounded, the second node is connected to the positive phase terminal of the operational amplifier, the output end of the operational amplifier is connected to the second end of the threshold adjustment circuit, the output end of the operational amplifier is connected to the negative phase terminal of the operational amplifier, and the ground end of the operational amplifier is grounded.

10. A device, characterized in that The invention comprises an overcurrent protection device as claimed in any one of claims 1 to 9.

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