An overcurrent protection device

Abstract

The application discloses an overcurrent protection device, and belongs to the technical field of switch control, which comprises a switch module arranged on a circuit connected between a power supply and a load; a control module electrically connected with the switch module and used for controlling the switch module to turn on or turn off the circuit; and a detection module, an input end of the detection module being electrically connected to the circuit, an output end of the detection module being electrically connected with the control module, the detection module acquiring an electric signal on the circuit and outputting an off signal when the electric signal meets preset conditions; and the control module being used for controlling the switch module to turn off the circuit when the off signal is received. The detection module can output the off signal when the electric signal meets the preset conditions, and then drive the control module to control the switch module to turn off the circuit, so that the safety of the circuit and the load on the circuit is ensured.

Description

Technical Field

[0001] This invention belongs to the field of switch control technology, specifically, it relates to an overcurrent protection device. Background Technology

[0002] A switching power supply is a power converter that transforms AC power into DC power, thereby providing a stable operating voltage for the load. When the load needs power, it sends a drive signal to the switching power supply, which then initiates the power supply operation upon receiving the signal.

[0003] As can be seen from the above working process, for a switching power supply, if a fault occurs in the circuit where the load is located, simply blocking the drive signal and then immediately restoring the drive signal when the fault seems to disappear is not enough to effectively protect the circuit and the load on the circuit. This is because after the drive signal is blocked, the switching power supply stops working, and the fault signal detected at this time does not truly reflect the information under the fault state. Therefore, it is easy to make a misjudgment and restore the drive signal, causing the switching power supply to start working. However, after starting, the switching power supply will automatically shut down due to circuit abnormalities, resulting in frequent starting and stopping of the switching power supply.

[0004] Especially when serious faults such as short circuits occur, this simple blocking and recovery strategy cannot meet safety requirements. In such situations, relying solely on blocking drive signals may result in repeated damage to the circuit due to a lack of effective protection. Therefore, introducing overcurrent protection devices is particularly important. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an overcurrent protection device for detecting circuit faults and automatically shutting off the circuit when a circuit fault occurs.

[0006] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0007] An overcurrent protection device, comprising:

[0008] A switching module is installed on the circuit where the power supply and load are connected.

[0009] A control module, electrically connected to the switch module, is used to control the switch module to turn the circuit on or off.

[0010] The detection module has its input terminal electrically connected to the circuit and its output terminal electrically connected to the control module. The detection module acquires electrical signals on the circuit and outputs a shutdown signal when the electrical signals meet preset conditions.

[0011] The control module is used to control the switch module to turn off the circuit when it receives the shutdown signal.

[0012] Furthermore, the electrical signal includes voltage and / or current, and the detection module is configured to:

[0013] When the voltage exceeds the upper threshold voltage and / or the current reaches the preset current value, the shutdown signal is output.

[0014] Furthermore, the upper threshold voltage has a corresponding lower threshold voltage, and the detection module is further configured to:

[0015] After outputting the shutdown signal, the voltage on the circuit is obtained;

[0016] If the voltage drops from above the lower threshold voltage to below the lower threshold voltage within a preset time period, a power supply signal is output.

[0017] The control module is used to control the switch module to turn on the circuit when it receives the power supply signal.

[0018] Furthermore, the detection module includes a first resistor, a second resistor, a third resistor, an IC chip, and a first power supply module;

[0019] One end of the first resistor is electrically connected to the circuit, and the other end is electrically connected to the non-inverting input terminal of the IC chip;

[0020] One end of the second resistor is electrically connected to the first power supply module, and the other end is electrically connected to the non-inverting input terminal of the IC chip;

[0021] One end of the third resistor is electrically connected to the non-inverting input terminal of the IC chip, and the other end is electrically connected to the output terminal of the IC chip.

[0022] The inverting input terminal of the IC chip is electrically connected to the first power supply module.

[0023] Furthermore, the first resistor and the second resistor share a common terminal on the non-inverting input terminal of the IC chip;

[0024] When the voltage at the common terminal is equal to the voltage at the inverting input terminal of the IC chip, an upper threshold voltage or a lower threshold voltage corresponding to the upper threshold voltage is formed on the IC chip.

[0025] Furthermore, the detection module also includes a fourth resistor and a fifth resistor connected in series. The end of the fourth resistor away from the fifth resistor is electrically connected to the first power supply module, and the end of the fifth resistor away from the fourth resistor is grounded.

[0026] The inverting input terminal of the IC chip is electrically connected to the common terminal of the fourth resistor and the fifth resistor, and the voltage on the inverting input terminal of the IC chip is determined by the fourth resistor and the fifth resistor.

[0027] Furthermore, the control module includes a first transistor, a second transistor, a second switching transistor, and a second power supply module;

[0028] The base of the first transistor is electrically connected to the collector of the second transistor, the collector of the first transistor is electrically connected to the control terminal of the second switching transistor, and the emitter of the first transistor is grounded.

[0029] The base of the second transistor is electrically connected to the output terminal of the IC chip, and the emitter of the second transistor is grounded.

[0030] The input terminal of the second switching transistor is electrically connected to the second power supply module, and the output terminal of the second switching transistor is electrically connected to the control terminal of the switching module.

[0031] Preferably, when the collector and emitter of the first transistor are turned on, the second switch is closed, and the second power supply module supplies power to the switch module. When the switch module is powered on, the circuit is turned on.

[0032] Furthermore, the second switch includes a PMOS transistor and a sixth resistor;

[0033] The source of the PMOS transistor is electrically connected to one end of the sixth resistor, and the common terminal of the source of the PMOS transistor and the sixth resistor is the input terminal of the second switch.

[0034] The gate of the PMOS transistor is electrically connected to the other end of the sixth resistor, and the common terminal of the gate of the PMOS transistor and the sixth resistor is the control terminal of the second switch.

[0035] The drain of the PMOS transistor is the output terminal of the second switching transistor.

[0036] Furthermore, the switching module includes an NMOS transistor and a seventh resistor;

[0037] The drain of the NMOS transistor is electrically connected to the power supply.

[0038] The gate of the NMOS transistor is electrically connected to one end of the seventh resistor, and the common terminal of the gate of the NMOS transistor and the seventh resistor is the control terminal of the switching module.

[0039] The source of the NMOS transistor is connected to the other end of the seventh resistor, and the common terminal of the source of the NMOS transistor and the seventh resistor is the output terminal of the switching module.

[0040] Preferably, the output terminal of the switch module is provided with an eighth resistor, the end of the eighth resistor closer to the switch module is electrically connected to the detection module, and the end of the eighth resistor further away from the switch module is electrically connected to the load.

[0041] Furthermore, it also includes an indicator light, the input terminal of which is electrically connected to the circuit, and the output terminal of which is grounded.

[0042] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0043] 1. This invention includes a control module and a detection module. The control module has the function of automatically controlling the switching module to turn on the circuit. After the switching module turns on the circuit, the detection module acquires the voltage and / or current on the circuit in real time. When the voltage exceeds the upper threshold voltage and / or the current reaches a preset current value, a circuit fault is determined. At this time, the detection module drives the control module to control the switching module to turn off the circuit by outputting a shutdown signal, thus preventing damage or burnout of the load on the circuit due to excessive voltage or current, and ensuring the safety of the circuit and the load on the circuit.

[0044] 2. The detection module of this invention also includes a lower threshold voltage corresponding to the upper threshold voltage. When the circuit fault is cleared and the circuit is powered on again, the detection module continues to acquire the voltage on the circuit. When the voltage changes from high to low and falls below the lower threshold voltage, it outputs a power supply signal. Upon receiving the power supply signal, the control module controls the switch module to turn on the circuit. Subsequently, the control module continues to execute corresponding controls based on the output of the detection module to achieve the purpose of automatically turning the circuit on or off. Attached Figure Description

[0045] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0046] Figure 1 This is a block diagram of an overcurrent protection device according to the present invention;

[0047] Figure 2 This is a circuit diagram of an overcurrent protection device according to the present invention.

[0048] Explanation of reference numerals in the attached diagram: 1. Switch module; 2. Control module; 3. Detection module; 4. Drive module.

[0049] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the appendices in the embodiments of the present invention. Figure 1-2 The technical solutions in the embodiments are clearly and completely described below. The embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0051] In the description of this invention, it should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product or device.

[0052] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0053] like Figure 1 and Figure 2 The present invention provides an overcurrent protection device, which is mainly used to detect circuit faults in the power supply and load, and automatically shuts off the circuit when a circuit fault is detected, so as to protect the circuit and the load located on the circuit. The load can be a household smart device, such as a water heater, washing machine, or air conditioner, or it can be a production equipment in an industrial setting or other types of electronic equipment. The embodiments of the present invention do not limit the load.

[0054] The overcurrent protection device mainly includes a switching module 1, a control module 2, and a detection module 3. Figure 1 In the diagram, the direction of the arrow indicates the direction of current flow.

[0055] In this embodiment, switch module 1 is mounted on the circuit. In practical applications, switch module 1 can be a mechanical switch or a solid-state switch. However, in this embodiment, because switch module 1 needs to be controlled by control module 2 to automatically turn the circuit on or off, reducing manual intervention, a solid-state switch is chosen. The solid-state switch can be a transistor or a field-effect transistor; preferably, switch module 1 uses a field-effect transistor.

[0056] In a specific example, switch module 1 includes an NMOS transistor and a seventh resistor, attached... Figure 2 In this diagram, the NMOS transistor and the seventh resistor are represented by M1 and R7, respectively. The drain of the NMOS transistor M1 is electrically connected to the power supply, which has the ability to provide electrical energy. The power supply includes, but is not limited to, power generation equipment and energy storage equipment. This invention does not limit the power supply, as long as it can supply power to the load. The gate of the NMOS transistor M1 is electrically connected to one end of the seventh resistor R7. The common terminal of the gate of the NMOS transistor M1 and the seventh resistor R7 serves as the overall control terminal of the switching module 1. This control terminal is used to determine whether the NMOS transistor M1 is closed. When the NMOS transistor M1 is closed, the circuit is conducting. The source of the NMOS transistor M1 is electrically connected to the other end of the seventh resistor R7. The common terminal of the source of the NMOS transistor M1 and the seventh resistor R7 serves as the overall output terminal of the switching module 1. This output terminal is used to output parameters such as voltage and current provided by the power supply.

[0057] To reduce interference from circuit signals on the NMOS transistor and improve the stability of NMOS transistor M1, this invention includes a first capacitor. Figure 2 In the diagram, the first capacitor is represented by C1. The first capacitor C1 is connected in parallel with the seventh resistor R7, that is, one end of the first capacitor C1 is electrically connected to the source of the NMOS transistor M1, and the other end is electrically connected to the gate of the NMOS transistor.

[0058] An eighth resistor is provided on the output terminal of the aforementioned switch module 1. Figure 2 In this circuit, the eighth resistor is denoted by R8. One end of the eighth resistor R8, closer to the switch module 1, is electrically connected to the detection module 3, and the other end is electrically connected to the load. That is, after the switch module 1 turns on the circuit, the power supply provides power to the load through the switch module 1 and the eighth resistor R8, while the detection module 3 can obtain the electrical signals on the circuit in real time from the end of the eighth resistor R8 closer to the switch module 1. The electrical signals include voltage and / or current.

[0059] The control terminal of the aforementioned switch module 1 is electrically connected to the control module 2. Switch module 1 is controlled by the control module 2 and can turn the circuit on or off. In a specific example, the control module 2 includes a first transistor, a second transistor, a second switching transistor, and a second power supply module. Figure 2In the diagram, the first transistor, the second transistor, and the second power supply module are represented by P1, P2, and VCC2, respectively. Specifically:

[0060] The base of the first transistor P1 is electrically connected to the collector of the second transistor P2. The collector of the first transistor P1 is electrically connected to the control terminal of the second switching transistor. The emitter of the first transistor P1 is grounded.

[0061] The base of the second transistor P2 is electrically connected to the output terminal of the detection module 3, and the emitter of the second transistor P2 is grounded.

[0062] The input terminal of the second switching transistor is electrically connected to the second power supply module VCC2, and the output terminal of the second switching transistor is electrically connected to the control terminal of the switching module 1.

[0063] Furthermore, the second switching transistor includes a PMOS transistor and a sixth resistor, denoted by M2 and R6, respectively. The source of the PMOS transistor M2 is electrically connected to one end of the sixth resistor R6. The common terminal of the source of the PMOS transistor M2 and the sixth resistor R6 is the overall input terminal of the second switching transistor, which is electrically connected to the second power supply module VCC2. To ensure that the second power supply module VCC2 provides a stable voltage to the second switching transistor, a second capacitor is also provided in the second switching transistor. Figure 2 In this circuit, the second capacitor is represented by C2, and it is connected in parallel with the sixth resistor R6. The gate of PMOS transistor M2 is electrically connected to the other end of the sixth resistor R6. The common terminal of the gate of PMOS transistor M2 and the sixth resistor R6 is the overall control terminal of the second switching transistor, which is electrically connected to the collector of the first transistor P1. The drain of PMOS transistor M2 is the output terminal of the second switching transistor, which is electrically connected to the control terminal of the switching module 1.

[0064] Furthermore, a ninth resistor is provided at the control terminal of the second switching transistor. Figure 2 In this diagram, the ninth resistor is denoted by R9. One end of the ninth resistor R9 is electrically connected to the control terminal of the second switching transistor, and the other end is electrically connected to the collector of the first transistor P1. A tenth resistor is provided at the output terminal of the second switching transistor. Figure 2 In this diagram, the tenth resistor is represented by R10. The output terminal of the second switch is electrically connected to the control terminal of switch module 1 through the tenth resistor R10.

[0065] In addition, both the first transistor P1 and the second transistor P2 mentioned above have built-in resistors. Figure 2 (Not shown in the diagram). The built-in resistors prevent excessive current or voltage from acting on the transistors, ensuring the stability of each transistor. To further protect the transistors and improve their stability, a third capacitor is connected in parallel with the first transistor P1. Figure 2In this diagram, the third capacitor is represented by C3. In practical applications, a capacitor can also be connected in parallel with the second transistor P2 to improve its stability; this invention does not impose any limitations on this.

[0066] In this design, an eleventh resistor and a twelfth resistor are located at the base of the first transistor P1, denoted as R11 and R12 in the attached diagram. The eleventh resistor R11 and the twelfth resistor R12 are connected in series. The end of the eleventh resistor R11 furthest from the twelfth resistor R12 is electrically connected to the base of the first transistor P1. The end of the twelfth resistor R12 furthest from the eleventh resistor R11 houses the third power supply module. Figure 2 In this diagram, the third power supply module is denoted as VCC3. The voltage provided by the third power supply module VCC3 is lower than the voltage provided by the second power supply module VCC2. In a specific example, the voltage provided by the third power supply module VCC3 is 5V, while the voltage provided by the second power supply module VCC2 is 12V.

[0067] Furthermore, the common terminal of the eleventh resistor R11 and the twelfth resistor R12 is electrically connected to the collector of the second transistor P2, and a thirteenth resistor is disposed on the base of the second transistor P2. Figure 2 In this diagram, the thirteenth resistor is represented by R13. The second transistor P2 is electrically connected to the output terminal of the detection module 3 through the thirteenth resistor R13.

[0068] In practical applications, the working process of the switch module 1 and the control module 2 working together is as follows:

[0069] First, the base of the first transistor P1 is powered by the third power supply module VCC3. When the base of the first transistor P1 is energized, its collector and emitter conduct. At this time, a loop is formed between the second power supply module VCC2, the sixth resistor R6, the ninth resistor R9, and the ground terminal of the emitter of the first transistor P1. When current flows through the sixth resistor R6, a voltage is generated across it. This voltage acts on the PMOS transistor, causing it to close, thus forming a loop between the second power supply module VCC2, the tenth resistor R10, the seventh resistor R7, the eighth resistor R8, and the detection module 3. When current flows through the seventh resistor R7, a voltage is generated across it. This voltage acts on the NMOS transistor, causing it to close, thus forming a new loop between the power supply, the eighth resistor R8, and the load. The power supply then supplies power to the load, achieving the purpose of automatically controlling the power supply to power the load.

[0070] After the power supply supplies power to the load, the detection module 3 acquires the electrical signals on the circuit in real time, and determines whether the circuit has a fault by using the electrical signals and the built-in preset conditions.

[0071] In a specific example, detection module 3 includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, an IC chip, and a first power supply module. Figure 2 In this diagram, the first resistor, second resistor, third resistor, fourth resistor, fifth resistor, and first power supply module are represented by R1, R2, R3, R4, R5, and VCC1, respectively. The IC chip is preferably an IC5 chip, therefore it is represented by IC5. Specifically:

[0072] One end of the first resistor R1 is electrically connected to the end of the eighth resistor R8 that is closer to the switch module 1, and the other end of the first resistor R1 is electrically connected to the non-inverting input terminal of the IC5 chip.

[0073] One end of the second resistor R2 is electrically connected to the first power supply module VCC1, and the other end of the second resistor R2 is electrically connected to the non-inverting input terminal of the IC5 chip.

[0074] One end of the third resistor R3 is electrically connected to the non-inverting input terminal of the IC5 chip, and the other end of the third resistor R3 is electrically connected to the output terminal of the IC5 chip.

[0075] The fourth resistor R4 and the fifth resistor R5 are connected in series. The end of the fourth resistor R4 furthest from the fifth resistor R5 is electrically connected to the first power supply module VCC1, and the end of the fifth resistor R5 furthest from the fourth resistor R4 is grounded. The inverting input terminal of the IC5 chip is electrically connected to the common terminal of the fourth and fifth resistors R4 and R5. In practical applications, the resistance values ​​of the fourth and fifth resistors R4 and R5 can be set as needed to control the voltage generated at the inverting input terminal of the IC5 chip. In a specific example, the voltage provided by the first power supply module VCC1 is 5V, and the resistance values ​​of the fourth resistor R4 and the fifth resistor R5 are 4.7kΩ and 7.5kΩ respectively. The voltage V generated at the inverting input terminal of the IC5 chip will then be... 反相 for:

[0076] V 反相 =5 - [5 / (R4+R5)]*R4, calculate V 反相 ≈3V.

[0077] Since the first power supply module VCC1 and the third power supply module VCC3 provide the same voltage in the embodiments of the present invention, they can use the same power supply device, such as the same battery, to reduce the number of power supply modules required and facilitate subsequent management. In practical applications, the first power supply module VCC1 and the third power supply module VCC3 can be customized as needed to determine whether they are the same power supply device; the embodiments of the present invention do not impose any limitations on this.

[0078] The aforementioned IC5 chip, in addition to having a non-inverting input, an inverting input, and an output, also has a positive power supply terminal and a negative power supply terminal. Figure 2 In the diagram, the non-inverting input, inverting input, output, positive power supply, and negative power supply are represented by +in, -in, out, +vs, and -vs, respectively. The positive power supply is electrically connected to the first power supply module VCC1, and the negative power supply is grounded. The first power supply module VCC1 supplies power to the IC5 chip. To ensure the stability of the IC5 chip, a fourth capacitor (C4) is connected in parallel with it. One end of the fourth capacitor C4 is electrically connected to the first power supply module VCC1, and the other end is grounded. Additionally, to reduce interference from other signals, a fifth capacitor is also provided for the IC5 chip. Figure 2 In the diagram, the fifth capacitor is represented by C5. One end of the fifth capacitor C5 is electrically connected to the non-inverting input terminal of the IC5 chip, and the other end is grounded.

[0079] Furthermore, the first resistor R1, the second resistor R2, and the third resistor R3, together with the IC5 chip, form a hysteresis comparator. This hysteresis comparator has an upper threshold voltage and a lower threshold voltage. In practical applications, when the voltage applied to the non-inverting input of the IC5 chip is equal to the voltage applied to the inverting input, an upper threshold voltage or a corresponding lower threshold voltage is generated on the IC5 chip. That is, when the voltage applied to the non-inverting input of the IC5 chip is equal to the voltage applied to the inverting input, the voltage output of the hysteresis comparator flips, switching from a high level to a low level, or vice versa.

[0080] In a specific example, the formula for calculating the upper threshold voltage is:

[0081] First, according to the principle of virtual open circuit, the IC5 chip is disconnected, or in other words, the resistance of the IC5 chip is much greater than the resistance of the third resistor R3. At this point, the current that would normally flow into the IC5 chip passes directly through the third resistor R3. In practical applications, since the voltage on the circuit is usually greater than the voltage provided by the first power supply module VCC1, the current that would normally flow into the IC5 chip will also pass through the second resistor R2. That is to say, the current flowing through the first resistor R1 is the sum of the current flowing through the second resistor R2 and the current flowing through the third resistor R3, therefore:

[0082]

[0083] Among them, V out V is the voltage at the output terminal of the IC5 chip. p V is the voltage at the non-inverting input terminal of the IC5 chip. inThis is the voltage across the end of the first resistor R1 furthest from the IC5 chip, and it is also the voltage across the circuit.

[0084] In the embodiments of this invention, it is assumed that R1 = 4.7kΩ, R2 = 4.7kΩ, and R3 = 2kΩ. As described above, VCC1 uses 5V. Furthermore, it was explained that when the voltage at the non-inverting input terminal of the IC5 chip is equal to the voltage at the inverting input terminal, an upper threshold voltage is generated. Since the voltage at the inverting input terminal of the IC5 chip is set to 3V, then Vp = V... 反相 =3V.

[0085] Then, substituting R1 = 4.7kΩ, R2 = 4.7kΩ, R3 = 2kΩ, VCC1 = 5V, and Vp = 3V into equation (1), we obtain V in With V out The relationship is as follows:

[0086] V in =1.705-0.235V out (2)

[0087] Since the first power supply module VCC1 provides 5V to the IC5 chip through the positive power supply terminal +vs, or in other words, the IC5 chip is powered by 5V, the voltage at the output terminal of the IC5 chip has two states: one is 5V (output is high level), and the other is 0V (output is low level).

[0088] Therefore, in V out When V = 0V, V in The maximum input voltage is used as the upper threshold voltage of the hysteresis comparator, i.e.:

[0089] V T+ =V in =1.705 - 0.235 * 0 = 1.705V (3)

[0090] V T+ This is the upper threshold voltage of the hysteresis comparator.

[0091] Furthermore, the current threshold that the circuit can withstand can be calculated based on the upper threshold voltage of the hysteresis comparator, i.e.:

[0092] I = V T+ / R8 (4)

[0093] In an embodiment of the present invention, R8 = 0.3Ω, so I ≈ 5.7A.

[0094] After obtaining the current threshold that the circuit can withstand, the current threshold is stored as a preset current value.

[0095] Furthermore, the formula for calculating the lower threshold voltage corresponding to the upper threshold voltage is as follows:

[0096] In V out When = 5V, V in With a minimum input voltage, this minimum input voltage is used as the lower threshold voltage of the hysteresis comparator, i.e.:

[0097] V T- =V in =1.705-0.235*5=0.53V (5)

[0098] V T- This is the lower threshold voltage of the hysteresis comparator.

[0099] Therefore, based on the above example, the upper threshold voltage of the hysteresis comparator is 1.705V, the lower threshold voltage is 0.53V, and the preset current is 5.7A.

[0100] It should be noted that the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the eighth resistor R8 involved in the above calculation process, as well as the voltage provided by the first power supply module VCC1 and the voltage output by the ic5 chip, can be customized according to actual needs. This embodiment of the invention does not impose any restrictions.

[0101] Based on the obtained upper threshold voltage, the IC5 chip acquires the voltage on the circuit in real time and determines whether the voltage exceeds the upper threshold voltage. If the voltage exceeds the upper threshold voltage, it indicates that a fault similar to a short circuit has occurred, causing the voltage to increase. In this case, the IC5 chip determines that there is a circuit fault, and the IC5 chip switches from a low level to a high level. Upon receiving the high level, the collector and emitter of the second transistor P2 are turned on, and the third power supply module VCC3, the twelfth resistor R12, and the second transistor P2 form a loop. At this time, the collector and emitter of the first transistor P1 are disconnected, further driving the second switching transistor to disconnect, causing the switching module 1 to also disconnect, i.e., the switching module 1 automatically shuts off the circuit. In other words, when the voltage on the circuit exceeds the upper threshold voltage, the control module 2 can automatically control the switching module 1 to disconnect the circuit, preventing excessive voltage from damaging the circuit and its load.

[0102] It should be noted that since the IC5 chip outputs a high level, which drives the control module 2 to control the switch module 1 to disconnect the circuit, the high level output of the IC5 chip is also called the shutdown signal. Similarly, when the IC5 chip outputs a low level, which drives the control module 2 to control the switch module 1 to turn on the circuit, the low level output of the IC5 chip is also called the power supply signal. In other words, the shutdown signal is a high-level signal, while the power supply signal is a low-level signal.

[0103] Based on the obtained preset current value, a current sensor (not shown in the attached diagram) can be installed on the circuit to detect the current in real time. Simultaneously, a processor (not shown in the attached diagram) is added to the aforementioned detection module 3. The processor, such as an MCU, can be integrated with the IC5 chip on a single circuit board or installed separately. The processor and the current sensor are communicatively connected; the specific communication connection method can be wired or wireless, and this embodiment of the invention is not limited thereto. The current sensor transmits the detected current to the processor, which determines whether the current in the circuit has reached the preset current value. If the current in the circuit reaches the preset current value, the processor determines that there is a circuit fault. The processor controls the IC5 chip to switch its output from low to high. After the IC5 chip outputs a high level, following the processing procedure described above for voltage exceeding the upper threshold voltage, the control module 2 can automatically control the switch module 1 to disconnect the circuit, preventing excessive voltage from damaging the circuit and its load.

[0104] Of course, a current sensor can also be set on the non-inverting input of the IC5 chip. The processor calculates the specific current value in the circuit based on the detection result of the current sensor, and then compares the current in the circuit with the preset current value. In practical applications, other methods can also be used to detect the current magnitude in the circuit, and this embodiment of the invention does not impose specific limitations.

[0105] In practical applications, the IC5 chip can be controlled to switch from low to high level when the voltage on the circuit exceeds the upper threshold voltage and the current on the circuit reaches the preset current value; alternatively, the IC5 chip can be controlled to switch from low to high level when the voltage on the circuit exceeds the upper threshold voltage or the current on the circuit reaches the preset current value. The specific setting method can be selected as needed, and this embodiment of the invention does not impose any restrictions.

[0106] Based on the obtained lower threshold voltage, the IC5 chip acquires the voltage on the circuit in real time. When it is determined that the voltage on the circuit has not exceeded the upper threshold voltage, the IC5 chip keeps the output at a low level.

[0107] To ensure that the IC5 chip can switch from a high-level output to a low-level output and continue subsequent detection after the circuit fault is cleared, the overcurrent protection device of this invention also includes a drive module 4. One end of the drive module 4 is electrically connected to the second power supply module VCC2, and the other end is electrically connected to the control terminal of the switch module 1. In a specific example, the drive module 4 includes a third transistor, a fourteenth resistor, and a controller. Figure 2 In this diagram, the third transistor and the fourteenth resistor are represented by P3 and R14, respectively, and the controller is either an MCU controller or a CPU controller. One end of the fourteenth resistor R14 is electrically connected to the second power supply module VCC2, and the other end is electrically connected to the collector of the third transistor P3. The emitter of the third transistor P3 is electrically connected to the control terminal of the switching module 1, and the base of the third transistor P3 is electrically connected to the controller.

[0108] The controller can receive commands input by the user through a user terminal or interactive terminal. User terminals include electronic devices such as mobile phones, tablets, computers, and smartwatches, while interactive terminals include operable touchscreens and display panels. After the circuit fault is cleared, the user inputs a command through the user terminal or interactive terminal. Upon receiving the command, the controller controls the third transistor P3 to close, forming a loop with the second power supply module VCC2, the fourteenth resistor R14, the seventh resistor R7, the eighth resistor R8, and the detection module 3. When current flows through the seventh resistor R7, a voltage is generated across it. This voltage acts on the NMOS transistor, causing it to close, thus forming a new loop with the power supply, the eighth resistor R8, and the load. The power supply then supplies power to the load, achieving the goal of automatically controlling the power supply to power the load after the circuit fault is cleared.

[0109] After the power supply re-energizes the load, the IC5 chip continues to acquire the voltage on the circuit and determines whether the voltage is lower than the lower threshold voltage. If the voltage is lower than the lower threshold voltage, it indicates that the voltage does not meet the conditions for shutting down the circuit. At this time, the IC5 chip determines that the circuit fault is resolved, and the IC5 chip switches from a high level to a low level. The collector and emitter of the second transistor P2, which receives the low level, disconnect, allowing the third power supply module VCC3 to re-energize the base of the first transistor P1. The collector and emitter of the first transistor P1 then conduct. At this time, the second power supply module VCC2, the sixth resistor R6, the ninth resistor R9, and the ground terminal of the emitter of the first transistor P1 form a loop. When current flows through the sixth resistor R6, a voltage is generated across the sixth resistor R6. This voltage acts on the PMOS transistor, causing the PMOS transistor to close, thus forming a loop with the second power supply module VCC2, the tenth resistor R10, the seventh resistor R7, the eighth resistor R8, and the detection module 3. When current flows through the seventh resistor R7, a voltage is generated across the seventh resistor R7. This voltage acts on the NMOS transistor, causing the NMOS transistor to close, so that the power supply, the eighth resistor R8, and the load form a new circuit, and the power supply supplies power to the load, thus achieving the purpose of automatically controlling the power supply to supply power to the load.

[0110] When the control module 2 controls the switch module 1 to conduct the circuit, the drive module 4 stops working. Specifically, the controller is connected to the processor. When the IC5 chip detects that the voltage on the circuit is lower than the lower threshold voltage, the processor sends a stop command to the controller. Upon receiving the stop command, the controller controls the third transistor P3 to disconnect, thereby allowing the control module 2 to control the switch module 1 to conduct the circuit, while the detection module 3 continues to detect whether a fault has occurred in the circuit.

[0111] It should be noted that the present invention sets a preset time after the circuit is re-energized to the point where the detection module 3 obtains the voltage on the circuit. During this preset time period, the circuit does not switch between being turned on and off, so as to avoid voltage changes on the circuit being caused by the switching between being turned on and off, thereby ensuring the accuracy of the detection results obtained by the detection module 3.

[0112] In addition, the present invention also includes an indicator light, the input terminal of which is electrically connected to the circuit, the output terminal of which is grounded, and a fifteenth resistor is provided on the input terminal of the indicator light. Figure 2 In the diagram, the indicator light and the fifteenth resistor are represented by LED and R15, respectively. The input terminal of the indicator light LED is electrically connected to the circuit through the fifteenth resistor R15. The fifteenth resistor R15 can act as a voltage divider to prevent excessive voltage from being applied to the indicator light LED.

[0113] By setting up indicator LEDs, the indicator LEDs will light up when the power supply is supplying power to the load, that is, when the circuit is energized, so that users can quickly know that the circuit is energized and ensure users' safe use of electricity.

[0114] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An overcurrent protection device, characterized in that, include: A switch module (1) is installed on the circuit where the power supply and load are connected; The control module (2) is electrically connected to the switch module (1) and is used to control the switch module (1) to turn on or off the circuit; The detection module (3) has its input terminal electrically connected to the circuit and its output terminal electrically connected to the control module (2). The detection module (3) acquires the electrical signal on the circuit and outputs a shutdown signal when the electrical signal meets a preset condition. The control module (2) is used to control the switch module (1) to turn off the circuit when the shutdown signal is received.

2. The overcurrent protection device according to claim 1, characterized in that, The electrical signal includes voltage and / or current, and the detection module (3) is configured to: When the voltage exceeds the upper threshold voltage and / or the current reaches the preset current value, the shutdown signal is output.

3. The overcurrent protection device according to claim 2, characterized in that, The upper threshold voltage has a corresponding lower threshold voltage, and the detection module (3) is further configured to: After outputting the shutdown signal, the voltage on the circuit is obtained; If the voltage drops from above the lower threshold voltage to below the lower threshold voltage within a preset time period, a power supply signal is output. The control module (2) is used to control the switch module (1) to turn on the circuit when the power supply signal is received.

4. The overcurrent protection device according to any one of claims 1-3, characterized in that, The detection module (3) includes a first resistor, a second resistor, a third resistor, an IC chip, and a first power supply module; One end of the first resistor is electrically connected to the circuit, and the other end is electrically connected to the non-inverting input terminal of the IC chip; One end of the second resistor is electrically connected to the first power supply module, and the other end is electrically connected to the non-inverting input terminal of the IC chip; One end of the third resistor is electrically connected to the non-inverting input terminal of the IC chip, and the other end is electrically connected to the output terminal of the IC chip. The inverting input terminal of the IC chip is electrically connected to the first power supply module.

5. The overcurrent protection device according to claim 4, characterized in that, The first resistor and the second resistor have a common terminal on the non-inverting input terminal of the IC chip; When the voltage at the common terminal is equal to the voltage at the inverting input terminal of the IC chip, an upper threshold voltage or a lower threshold voltage corresponding to the upper threshold voltage is formed on the IC chip.

6. The overcurrent protection device according to claim 5, characterized in that, The detection module (3) further includes a fourth resistor and a fifth resistor connected in series. The end of the fourth resistor away from the fifth resistor is electrically connected to the first power supply module, and the end of the fifth resistor away from the fourth resistor is grounded. The inverting input terminal of the IC chip is electrically connected to the common terminal of the fourth resistor and the fifth resistor, and the voltage on the inverting input terminal of the IC chip is determined by the fourth resistor and the fifth resistor.

7. The overcurrent protection device according to any one of claims 4-6, characterized in that, The control module (2) includes a first transistor, a second transistor, a second switching transistor, and a second power supply module; The base of the first transistor is electrically connected to the collector of the second transistor, the collector of the first transistor is electrically connected to the control terminal of the second switching transistor, and the emitter of the first transistor is grounded. The base of the second transistor is electrically connected to the output terminal of the IC chip, and the emitter of the second transistor is grounded. The input terminal of the second switching transistor is electrically connected to the second power supply module, and the output terminal of the second switching transistor is electrically connected to the control terminal of the switching module (1). Preferably, when the collector and emitter of the first transistor are turned on, the second switch is closed, and the second power supply module supplies power to the switch module (1). When the switch module (1) is powered on, the circuit is turned on.

8. The overcurrent protection device according to claim 7, characterized in that, The second switch includes a PMOS transistor and a sixth resistor; The source of the PMOS transistor is electrically connected to one end of the sixth resistor, and the common terminal of the source of the PMOS transistor and the sixth resistor is the input terminal of the second switch. The gate of the PMOS transistor is electrically connected to the other end of the sixth resistor, and the common terminal of the gate of the PMOS transistor and the sixth resistor is the control terminal of the second switch. The drain of the PMOS transistor is the output terminal of the second switching transistor.

9. The overcurrent protection device according to claim 7, characterized in that, The switching module (1) includes an NMOS transistor and a seventh resistor; The drain of the NMOS transistor is electrically connected to the power supply. The gate of the NMOS transistor is electrically connected to one end of the seventh resistor, and the common terminal of the gate of the NMOS transistor and the seventh resistor is the control terminal of the switching module (1). The source of the NMOS transistor is connected to the other end of the seventh resistor, and the common terminal of the source of the NMOS transistor and the seventh resistor is the output terminal of the switching module (1). Preferably, the output terminal of the switch module (1) is provided with an eighth resistor, the end of the eighth resistor close to the switch module (1) is electrically connected to the detection module (3), and the end of the eighth resistor away from the switch module (1) is electrically connected to the load.

10. The overcurrent protection device according to claim 1, characterized in that, It also includes an indicator light, the input of which is electrically connected to the circuit, and the output of which is grounded.

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