Overcurrent protection circuit and electronic device

Abstract

The present disclosure relates to an overcurrent protection circuit and an electronic device, the overcurrent protection circuit comprising: a first MOS tube, a second MOS tube, a diode, a sampling resistor, a first voltage dividing resistor, a second voltage dividing resistor, and a third voltage dividing resistor, the first MOS tube and the second MOS tube are both P-type MOS tubes, a first end of the sampling resistor is connected with a power supply, a second end of the sampling resistor is connected with a source electrode of the first MOS tube, a drain electrode of the first MOS tube is connected with a load, the second end of the sampling resistor is connected with a first end of the first voltage dividing resistor, a second end of the first voltage dividing resistor is connected with a gate electrode of the first MOS tube, the gate electrode of the first MOS tube and the second end of the first voltage dividing resistor are both connected with a first end of the second voltage dividing resistor, a second end of the second voltage dividing resistor is grounded, the first end of the sampling resistor is connected with a source electrode of the second MOS tube, a drain electrode of the second MOS tube is grounded through the third voltage dividing resistor, and the drain electrode of the second MOS tube is connected with the gate electrode of the first MOS tube through the diode.

Description

Technical Field

[0001] This disclosure relates to the field of circuit technology, and more specifically, to an overcurrent protection circuit and electronic device. Background Technology

[0002] Currently, overcurrent protection devices on the market are mainly packaged as chips, which are expensive and have limited voltage withstand capabilities. For automotive-grade products, due to the requirements of AEC (Automotive Electronics Council) certification, the cost of chip materials is several times higher than that of consumer products, which is very unfriendly to the design of automotive products. Utility Model Content

[0003] One objective of this invention is to provide a new technical solution for overcurrent protection circuits.

[0004] According to a first aspect of this utility model, an overcurrent protection circuit is provided, comprising: an overcurrent protection circuit including: a first MOSFET, a second MOSFET, a diode, a sampling resistor, a first voltage divider resistor, a second voltage divider resistor, and a third voltage divider resistor, wherein the first MOSFET and the second MOSFET are both P-type MOSFETs, wherein... The first terminal of the sampling resistor is connected to the power supply, the second terminal of the sampling resistor is connected to the source of the first MOSFET, the drain of the first MOSFET is connected to the load, the second terminal of the sampling resistor is connected to the first terminal of the first voltage divider resistor, the second terminal of the first voltage divider resistor is connected to the gate of the first MOSFET, the gate of the first MOSFET and the second terminal of the first voltage divider resistor are both connected to the first terminal of the second voltage divider resistor, and the second terminal of the second voltage divider resistor is grounded. The first end of the sampling resistor is connected to the source of the second MOS transistor, the drain of the second MOS transistor is grounded through the third voltage divider resistor, and the drain of the second MOS transistor is connected to the gate of the first MOS transistor through the diode.

[0005] Optionally, the overcurrent protection circuit further includes: a third MOSFET, a fourth MOSFET, a fourth voltage divider resistor, a fifth voltage divider resistor, a sixth voltage divider resistor, and a first capacitor, wherein the third MOSFET is a P-type MOSFET, and the fourth MOSFET is an N-type MOSFET. The source of the third MOS transistor is connected to the first terminal of the sampling resistor, the drain of the third MOS transistor is connected to the first terminal of the fourth voltage divider resistor, the second terminal of the fourth voltage divider resistor is grounded, the drain of the third MOS transistor is also connected to the drain of the second MOS transistor, the diode, and the first terminal of the third voltage divider resistor, and the gate of the third MOS transistor is connected to the first terminal of the fifth voltage divider resistor. The first capacitor and the sixth voltage divider resistor are connected in parallel. The first terminal of the first capacitor is connected to the first terminal of the sampling resistor, and the second terminal of the first capacitor is connected to the gate of the third MOSFET. The drain of the fourth MOS transistor is connected to the second terminal of the fifth voltage divider resistor, the source of the fourth MOS transistor is grounded, and the gate of the fourth MOS transistor is connected to the first terminal of the fourth voltage divider resistor, the drain of the third MOS transistor, the drain of the second MOS transistor, the diode, and the first terminal of the third voltage divider resistor.

[0006] Optionally, the overcurrent protection circuit further includes a second capacitor, which is connected in parallel with the third voltage divider resistor.

[0007] Optionally, when the power supply is normally supplying power to the load, the first MOSFET is in the on state and the second MOSFET is in the off state. In the event of an overcurrent, the second MOSFET is in the ON state, while the first MOSFET is in the OFF state.

[0008] Optionally, when the power supply is normally supplying power to the load, the first MOSFET is in the on state, and the second MOSFET, the third MOSFET, and the fourth MOSFET are all in the off state. In the event of an overcurrent, the second, third, and fourth MOSFETs are all in the ON state, while the first MOSFET is in the OFF state.

[0009] Optionally, the resistance values ​​of the sampling resistors are all less than the resistance values ​​of the first voltage divider resistor, the second voltage divider resistor, and the third voltage divider resistor.

[0010] Optionally, the resistance values ​​of the sampling resistors are all less than the resistance values ​​of the first voltage divider resistor, the second voltage divider resistor, the third voltage divider resistor, the fourth voltage divider resistor, the fifth voltage divider resistor, and the sixth voltage divider resistor.

[0011] According to a second aspect of the present invention, an electronic device is provided, comprising an overcurrent protection circuit, a power supply, and a load as described in the first aspect, wherein... One end of the overcurrent protection circuit is connected to the power supply, and the other end of the overcurrent protection circuit is connected to the load.

[0012] Optionally, the electronic device further includes a control switch, wherein the power supply is connected to the overcurrent protection circuit via the control switch.

[0013] Optionally, the control switch may be opened and then closed to allow the power supply to restore power to the load.

[0014] This disclosure provides an overcurrent protection circuit that uses two discrete components, namely a MOSFET and a diode, to construct an overcurrent protection resistor, thereby reducing costs. In addition, the overcurrent protection circuit provided by this disclosure, through the cooperation of the first MOSFET and the second MOSFET, enables normal power supply to the load and timely disconnection of the power supply circuit to the load when an overcurrent occurs, thus protecting the load.

[0015] The features and advantages of the embodiments of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of these embodiments.

[0017] Figure 1 This is a circuit diagram of an overcurrent protection circuit according to an embodiment of the present invention.

[0018] Figure 2 This is a circuit diagram of an overcurrent protection circuit according to another embodiment of the present invention.

[0019] Figure 3 This is a circuit diagram of an electronic device according to another embodiment of the present invention. Detailed Implementation

[0020] Various exemplary embodiments of this specification will now be described in detail with reference to the accompanying drawings.

[0021] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the embodiments of this specification or their application or use.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0023] To solve the above-mentioned technical problems, this disclosure provides an overcurrent protection circuit that uses two discrete components, namely a MOSFET and a diode, to construct an overcurrent protection resistor, thereby reducing costs. In addition, the overcurrent protection circuit provided by this disclosure, through the cooperation of the first MOSFET and the second MOSFET, enables normal power supply to the load and timely disconnection of the power supply circuit to the load when an overcurrent occurs, thus protecting the load.

[0024] <First Embodiment> In one embodiment of this utility model, an overcurrent protection circuit is provided. According to... Figure 1 As shown, the overcurrent protection circuit includes: a first MOSFET Q1, a second MOSFET Q2, a diode D1, a sampling resistor Rsense, a first voltage divider resistor R1, a second voltage divider resistor R2, and a third voltage divider resistor R3.

[0025] Both the first MOSFET Q1 and the second MOSFET Q2 are P-type MOSFETs. The diode D1 can be a 1N4004.

[0026] according to Figure 1 As shown, the first terminal of the sampling resistor Rsense is connected to the power supply ( Figure 1 (Not shown) The sampling resistor Rsense is connected to the source of the first MOSFET Q1, the drain of the first MOSFET Q1 is connected to the load, the sampling resistor Rsense is connected to the first end of the first voltage divider resistor R1, the second end of the first voltage divider resistor R1 is connected to the gate of the first MOSFET Q1, the gate of the first MOSFET Q1 and the second end of the first voltage divider resistor R1 are both connected to the first end of the second voltage divider resistor R2, and the second end of the second voltage divider resistor R2 is grounded.

[0027] The first terminal of the sampling resistor Rsense is connected to the source of the second MOSFET Q2. The drain of the second MOSFET Q2 is grounded through the third voltage divider resistor R3. The drain of the second MOSFET Q2 is connected to the gate of the first MOSFET Q1 through the diode D1.

[0028] When the power supply is normally supplying power to the load, the first MOSFET Q1 is in the on state and the second MOSFET Q2 is in the off state.

[0029] Specifically, when the power supply starts supplying power to the load, the voltage of the power supply is divided by the first voltage divider resistor R1 and the second voltage divider resistor R2, which pulls down the gate voltage of the first MOSFET Q1, causing Q1 to conduct. Meanwhile, the current from the power supply flows through the sampling resistor Rsense, preventing a large voltage drop, thus the gate voltage of the second MOSFET Q2 is not pulled down, and Q2 remains off. This ensures that the power supply can normally supply power to the load.

[0030] In the event of an overcurrent, the second MOSFET Q2 is in the on state, while the first MOSFET Q1 is in the off state.

[0031] Specifically, when an overcurrent occurs, the current flowing through the sampling resistor Rsense is large, resulting in a large voltage drop. This pulls down the gate voltage of the second MOSFET Q2, turning it on. Simultaneously, through diode D1, it pulls up the gate voltage of the first MOSFET Q1, turning it off. This promptly cuts off the power supply circuit to the load, thus protecting the load when an overcurrent occurs.

[0032] The resistance values ​​of the sampling resistors Rsense are all less than the resistance values ​​of the first voltage divider resistor R1, the second voltage divider resistor R2, and the third voltage divider resistor R3. This ensures that when the power supply is normally supplying power to the load, the first MOSFET Q1 is in the on state and the second MOSFET Q2 is in the off state, and that in the event of an overcurrent, the second MOSFET Q2 is in the on state and the first MOSFET Q1 is in the off state.

[0033] For example, the resistance of the sampling resistor Rsense is 1Ω, and the resistances of the first voltage divider resistor R1, the second voltage divider resistor R2, and the third voltage divider resistor R3 are all 10kΩ.

[0034] <Second Embodiment> In one embodiment of this utility model, an overcurrent protection circuit is provided. According to... Figure 2 As shown, the overcurrent protection circuit includes: a first MOSFET Q1, a second MOSFET Q2, a third MOSFET Q3, a fourth MOSFET Q4, a diode D1, a sampling resistor Rsense, a first voltage divider resistor R1, a second voltage divider resistor R2, a third voltage divider resistor R3, a fourth voltage divider resistor R4, a fifth voltage divider resistor R5, a sixth voltage divider resistor R6, and a first capacitor C1.

[0035] The first MOSFET Q1, the second MOSFET Q2, and the third MOSFET Q3 are all P-type MOSFETs. The fourth MOSFET Q4 is an N-type MOSFET.

[0036] according to Figure 2 As shown, the first terminal of the sampling resistor Rsense is connected to the power supply ( Figure 2 (Not shown) The sampling resistor Rsense is connected to the source of the first MOSFET Q1, the drain of the first MOSFET Q1 is connected to the load, the sampling resistor Rsense is connected to the first end of the first voltage divider resistor R1, the second end of the first voltage divider resistor R1 is connected to the gate of the first MOSFET Q1, the gate of the first MOSFET Q1 and the second end of the first voltage divider resistor R1 are both connected to the first end of the second voltage divider resistor R2, and the second end of the second voltage divider resistor R2 is grounded.

[0037] The first terminal of the sampling resistor Rsense is connected to the source of the second MOSFET Q2. The drain of the second MOSFET Q2 is grounded through the third voltage divider resistor R3. The drain of the second MOSFET Q2 is connected to the gate of the first MOSFET Q1 through the diode D1.

[0038] The source of the third MOSFET Q3 is connected to the first terminal of the sampling resistor Rsense. The drain of the third MOSFET Q3 is connected to the first terminal of the fourth voltage divider resistor R4. The second terminal of the fourth voltage divider resistor R4 is grounded. The drain of the third MOSFET Q3 is also connected to the drain of the second MOSFET Q2, the diode D1, and the first terminal of the third voltage divider resistor R3. The gate of the third MOSFET Q3 is connected to the first terminal of the fifth voltage divider resistor R5.

[0039] The first capacitor C1 and the sixth voltage divider resistor R6 are connected in parallel. The first terminal of the first capacitor C1 is connected to the first terminal of the sampling resistor Rsense, and the second terminal of the first capacitor C1 is connected to the gate of the third MOS transistor Q3.

[0040] The drain of the fourth MOSFET Q4 is connected to the second terminal of the fifth voltage divider resistor R5. The source of the fourth MOSFET Q4 is grounded. The gate of the fourth MOSFET Q4 is connected to the first terminal of the fourth voltage divider resistor R4, the drain of the third MOSFET Q3, the drain of the second MOSFET Q2, diode D1, and the first terminal of the third voltage divider resistor R3.

[0041] When the power supply is normally supplying power to the load, the first MOSFET Q1 is in the on state, while the second MOSFET Q2, the third MOSFET Q3, and the fourth MOSFET Q4 are all in the off state.

[0042] Specifically, when the power supply starts supplying power to the load, the power supply voltage, after being divided by the first voltage divider resistor R1 and the second voltage divider resistor R2, pulls down the gate voltage of the first MOSFET Q1, causing Q1 to conduct. Meanwhile, the current flowing through the sampling resistor Rsense prevents a large voltage drop, ensuring that the gate voltage of the second MOSFET Q2 is not pulled down and remains off. Because of the first capacitor C1, it acts as a short circuit the instant the power supply starts supplying power to the load, thus pulling up the gate voltage of the third MOSFET Q3, preventing it from conducting and keeping it off. Similarly, the gate voltage of the fourth MOSFET Q4 is pulled down, preventing it from conducting and keeping it off. This ensures that the power supply can normally supply power to the load.

[0043] In the event of an overcurrent, the second MOSFET Q2, the third MOSFET Q3, and the fourth MOSFET Q4 are all in the on state, while the first MOSFET Q1 is in the off state.

[0044] Specifically, when an overcurrent occurs, the current flowing through the sampling resistor Rsense is large, creating a large voltage drop. This pulls down the gate voltage of the second MOSFET Q2, turning it on. Simultaneously, through diode D1, it pulls up the gate voltage of the first MOSFET Q1, turning it off. This promptly disconnects the power supply circuit to the load, protecting the load during overcurrent. Since the second MOSFET Q2 is on, it pulls up the gate voltage of the fourth MOSFET Q4, turning it on. The fourth MOSFET Q4 is on, pulling down the gate voltage of the third MOSFET Q3, turning it on. Specifically, the sixth voltage divider resistor R6 provides a pull-up level to the drain of the fourth MOSFET Q4 and, after the fourth MOSFET Q4 is on, forms a voltage divider with the fifth voltage divider resistor R5 to pull down the gate voltage of the third MOSFET, turning it on. When the third MOSFET Q3 is turned on, the power supply goes through the third MOSFET Q3 to the diode D1, forming a positive feedback. This can continuously pull down the gate voltage of the first MOSFET Q1, keeping the first MOSFET in a stable off state. This can continuously cut off the power supply circuit to the load, thus protecting the load in case of overcurrent.

[0045] The sampling resistors Rsense are all less than the values ​​of the first voltage divider resistor R1, the second voltage divider resistor R2, the third voltage divider resistor R3, the fourth voltage divider resistor R4, the fifth voltage divider resistor R5, and the sixth voltage divider resistor R6. This ensures that when the power supply is normally supplying power to the load, the first MOSFET Q1 is on, while the second MOSFET Q2, the third MOSFET Q3, and the fourth MOSFET Q4 are all off. Furthermore, in the event of an overcurrent, the second MOSFET Q2, the third MOSFET Q3, and the fourth MOSFET Q4 are all on, while the first MOSFET Q1 is off.

[0046] For example, the resistance of the sampling resistor Rsense is 1Ω, and the resistances of the first voltage divider resistor R1, the second voltage divider resistor R2, the third voltage divider resistor R3, the fourth voltage divider resistor R4, the fifth voltage divider resistor R5, and the sixth voltage divider resistor R6 are all 10kΩ.

[0047] In some embodiments, according to Figure 2 As shown, the overcurrent protection circuit also includes a second capacitor C2. The second capacitor C2 is connected in parallel with the third voltage divider resistor R3. This serves to store energy and increase the stability of the shutdown action after an overcurrent occurs.

[0048] <Third Embodiment> In one embodiment of this utility model, an electronic device is provided. This electronic device includes an overcurrent protection circuit, a power supply, and a load as provided in any of the above embodiments. One end of the overcurrent protection circuit is connected to the power supply, and the other end of the overcurrent protection circuit is connected to the load. See details... Figure 3 .

[0049] In some embodiments, the electronic device further includes a control switch. The power supply is connected to an overcurrent protection circuit via the control switch.

[0050] In some embodiments, in the event of an overcurrent, the control switch is first opened and then closed to allow the power supply to restore power to the load.

[0051] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0052] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0053] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this specification. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of computer instructions, which contains one or more executable computer instructions for implementing a specified logical function. In some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions. It will be known to those skilled in the art that implementation in hardware, implementation in software, and implementation using a combination of software and hardware are equivalent.

[0054] Various embodiments of this specification have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. An overcurrent protection circuit, characterized by comprising: include: The system comprises a first MOSFET, a second MOSFET, a diode, a sampling resistor, a first voltage divider resistor, a second voltage divider resistor, and a third voltage divider resistor. Both the first and second MOSFETs are P-type MOSFETs. The first terminal of the sampling resistor is connected to the power supply, the second terminal of the sampling resistor is connected to the source of the first MOSFET, the drain of the first MOSFET is connected to the load, the second terminal of the sampling resistor is connected to the first terminal of the first voltage divider resistor, the second terminal of the first voltage divider resistor is connected to the gate of the first MOSFET, the gate of the first MOSFET and the second terminal of the first voltage divider resistor are both connected to the first terminal of the second voltage divider resistor, and the second terminal of the second voltage divider resistor is grounded. The first end of the sampling resistor is connected to the source of the second MOS transistor, the drain of the second MOS transistor is grounded through the third voltage divider resistor, and the drain of the second MOS transistor is connected to the gate of the first MOS transistor through the diode.

2. The overcurrent protection circuit of claim 1, wherein, The overcurrent protection circuit further includes: a third MOSFET, a fourth MOSFET, a fourth voltage divider resistor, a fifth voltage divider resistor, a sixth voltage divider resistor, and a first capacitor. The third MOSFET is a P-type MOSFET, and the fourth MOSFET is an N-type MOSFET. The source of the third MOS transistor is connected to the first terminal of the sampling resistor, the drain of the third MOS transistor is connected to the first terminal of the fourth voltage divider resistor, the second terminal of the fourth voltage divider resistor is grounded, the drain of the third MOS transistor is also connected to the drain of the second MOS transistor, the diode, and the first terminal of the third voltage divider resistor, and the gate of the third MOS transistor is connected to the first terminal of the fifth voltage divider resistor. The first capacitor and the sixth voltage divider resistor are connected in parallel. The first terminal of the first capacitor is connected to the first terminal of the sampling resistor, and the second terminal of the first capacitor is connected to the gate of the third MOSFET. The drain of the fourth MOS transistor is connected to the second terminal of the fifth voltage divider resistor, the source of the fourth MOS transistor is grounded, and the gate of the fourth MOS transistor is connected to the first terminal of the fourth voltage divider resistor, the drain of the third MOS transistor, the drain of the second MOS transistor, the diode, and the first terminal of the third voltage divider resistor.

3. The overcurrent protection circuit of claim 1, wherein, The overcurrent protection circuit also includes a second capacitor, which is connected in parallel with the third voltage divider resistor.

4. The overcurrent protection circuit according to claim 1, characterized in that, When the power supply is normally supplying power to the load, the first MOSFET is in the on state and the second MOSFET is in the off state. In the event of an overcurrent, the second MOSFET is in the ON state, while the first MOSFET is in the OFF state.

5. The overcurrent protection circuit according to claim 2, characterized in that, When the power supply is normally supplying power to the load, the first MOSFET is in the on state, and the second MOSFET, the third MOSFET, and the fourth MOSFET are all in the off state. In the event of an overcurrent, the second, third, and fourth MOSFETs are all in the ON state, while the first MOSFET is in the OFF state.

6. The overcurrent protection circuit according to claim 1, characterized in that, The resistance values ​​of the sampling resistors are all less than the resistance values ​​of the first voltage divider resistor, the second voltage divider resistor, and the third voltage divider resistor.

7. The overcurrent protection circuit according to claim 2, characterized in that, The resistance values ​​of the sampling resistors are all less than the resistance values ​​of the first voltage divider resistor, the second voltage divider resistor, the third voltage divider resistor, the fourth voltage divider resistor, the fifth voltage divider resistor, and the sixth voltage divider resistor.

8. An electronic device, characterized in that, include: The overcurrent protection circuit, power supply, and load as described in any one of claims 1-7, wherein, One end of the overcurrent protection circuit is connected to the power supply, and the other end of the overcurrent protection circuit is connected to the load.

9. The electronic device according to claim 8, characterized in that, The electronic device also includes a control switch, wherein the power supply is connected to the overcurrent protection circuit via the control switch.

10. The electronic device according to claim 9, characterized in that, The control switch is first opened and then closed to allow the power supply to restore power to the load.

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