Overvoltage protection module, power supply protection circuit and vehicle-mounted electronic equipment

Abstract

The utility model relates to an overvoltage protection module, a power supply protection circuit and a vehicle-mounted electronic device, the overvoltage protection module comprises a first voltage dividing unit connected between the positive and negative electrodes of a power supply, and a switch unit used for controlling the on-off of a circuit between the input and output of the power supply, and the switch unit is connected between the power supply and a load. The control end of the switch unit is connected with the first voltage dividing end of the first voltage dividing unit, and the switch unit is disconnected when the voltage of the control end is not smaller than the voltage of the input end. The overvoltage protection module further comprises a second voltage dividing unit connected between the positive electrode and the negative electrode of the power supply, a second switch tube which is controlled by the second voltage dividing unit and used for communicating the control end of the switch unit and the positive electrode input end of the power supply during conduction, and an adjusting unit which is connected and adjusted during overvoltage of the power supply so as to conduct the switch tube. The overvoltage protection module is not only used for overvoltage protection, but also can play a protection role during the reverse connection period of the power supply.

Description

Technical Field

[0001] The utility model relates to the technical field of protective circuit devices, and in particular to an overvoltage protection module, a power protection circuit and a vehicle-mounted electronic device. Background Art

[0002] In order to protect the normal operation of vehicle-mounted electronic devices, a power protection circuit is generally provided in the vehicle-mounted electronic devices to ensure that the normal operation of the vehicle-mounted electronic devices is not damaged by the vehicle-mounted electronic devices themselves or external factors.

[0003] However, the power protection circuits provided by related technologies are generally relatively simple overvoltage and filtering protection circuits, or relatively simple overcurrent and filtering protection circuits, which do not take into account the situation of reverse connection of the battery, thereby indirectly increasing the risk of damage to load components in vehicle-mounted electronic equipment. Utility Model Content

[0004] The technical problem to be solved by the present invention is to provide an overvoltage protection module, a power protection circuit and an on-vehicle electronic device.

[0005] The technical solution adopted by the present invention to solve the technical problem is to construct an overvoltage protection module, including:

[0006] a first voltage dividing unit, comprising a first end and a second end for connecting to the positive input end of the power supply and the negative input end of the power supply, respectively, and a first voltage dividing end for outputting a first voltage dividing signal;

[0007] A switch unit for controlling the on / off of a circuit between a power input and an output; the switch unit comprises an input terminal and an output terminal for connecting to a positive input terminal of the power supply and a positive output terminal of the load, respectively, and a control terminal connected to the first voltage divider terminal; the switch unit is configured to be disconnected when the voltage at its control terminal is greater than or equal to the voltage at its input terminal;

[0008] A switch control unit, comprising:

[0009] a second voltage dividing unit, comprising a first end and a second end for connecting to the positive input terminal of the power supply and the negative input terminal of the power supply, respectively, and a second voltage dividing end for outputting a second voltage dividing signal;

[0010] a switch tube, configured to connect the control terminal of the switch unit to the positive input terminal of the power supply when turned on; the control terminal of the switch tube is connected to the second voltage dividing terminal to be turned on and off according to the second voltage dividing signal;

[0011] The adjustment unit is connected to the second end of the second voltage dividing unit and is used to adjust the magnitude of the second voltage dividing signal to turn on the switch tube when the power supply is over-voltage.

[0012] In some embodiments, the switch unit includes a MOS transistor Q2, and the MOS transistor Q2 is a PMOS transistor.

[0013] In some embodiments, the adjustment unit includes a voltage regulator tube D2, a cathode of the voltage regulator tube D2 is connected to the second end of the second voltage divider unit, and an anode of the voltage regulator tube D2 is connected to the negative input terminal of the power supply;

[0014] The switch tube is a transistor Q1, and the transistor Q1 is a PNP transistor.

[0015] The present utility model also constructs a power supply protection circuit, including a filtering module, the filtering module includes an electrolytic capacitor C3, the positive pole of the electrolytic capacitor C3 is connected to the positive input terminal of the power supply, and the negative pole is connected to the negative output terminal of the load. The power supply protection circuit also includes the above-mentioned overvoltage protection module, and the overvoltage protection module is connected to the front end of the filtering module.

[0016] In some embodiments, the power protection circuit further includes a TVS tube D1 connected to the front end of the overvoltage protection module, wherein the cathode of the TVS tube D1 is connected between the positive input terminal of the power supply and the positive output terminal of the load, and the anode thereof is connected between the negative input terminal of the power supply and the negative output terminal of the load.

[0017] In some embodiments, the power protection circuit further includes a fuse F1 connected to the front end of the TVS tube D1 , and the fuse F1 is connected between the positive input terminal of the power supply and the positive output terminal of the load.

[0018] In some embodiments, the power protection circuit further includes an electrostatic protection module connected to the front end of the TVS tube D1; the electrostatic protection module includes several capacitive elements connected in series and connected between the positive input terminal of the power supply and the negative input terminal of the power supply.

[0019] In some embodiments, the power protection circuit further includes a discharge module connected to the rear end of the filter module; the discharge module includes at least one resistive element; one end of the resistive element is connected to the filter module, and the other end thereof is connected to the negative output terminal of the load.

[0020] In some embodiments, the power protection circuit further includes an electrostatic protection module; the electrostatic protection module includes a capacitor C1 and a capacitor C2 connected in series, connected between the positive input terminal of the power supply and the negative input terminal of the power supply;

[0021] The power protection circuit further includes a fuse F1, which is connected between the positive input terminal of the power supply and the overvoltage protection module;

[0022] The power protection circuit further includes a TVS tube D1 connected between the fuse F1 and the overvoltage protection module, wherein the cathode of the TVS tube D1 is connected between the positive input terminal of the power supply and the positive output terminal of the load, and the anode of the TVS tube D1 is connected between the negative input terminal of the power supply and the negative output terminal of the load;

[0023] The power protection circuit further includes a discharge module connected to the rear end of the filter module; the discharge module includes a resistor R5; one end of the resistor R5 is connected to the filter module, and the other end is connected to the negative output terminal of the load.

[0024] The utility model also constructs an on-vehicle electronic device, which comprises a load element and the above-mentioned power protection circuit; the power protection circuit is connected to the load element.

[0025] The implementation of the present invention has the following beneficial effects: In this overvoltage protection module, when the control terminal of the switch unit receives a divided positive power supply signal, the voltage at the control terminal of the switch unit will be less than the voltage at the input terminal of the switch unit due to the voltage division of the first voltage division unit, so that the voltage at the control terminal of the switch unit is less than the voltage at its input terminal; and when the control terminal of the switch unit receives a divided negative power supply signal, the positive terminal of the power supply is at a negative voltage, and the voltage at the input terminal of the switch unit is less than the voltage at the control terminal of the switch unit. At the same time, when the power supply is normally connected and overvoltage occurs, the switch tube connects the control terminal of the switch unit with the positive input terminal of the power supply under the action of the adjustment unit, so that the voltage at the control terminal of the switch unit is equivalent to the voltage at the input terminal of the switch unit.

[0026] Based on the above principle, the overvoltage protection module can not only be used for overvoltage protection, but also play a protective role during power reverse connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0028] Figure 1 is a circuit schematic diagram of the overvoltage protection module of the present utility model in some embodiments;

[0029] Figure 2 This is a circuit schematic diagram of the power protection circuit of the utility model in some embodiments.

[0030] Figure numerals: overvoltage protection module 1; switch unit 11; first voltage divider unit 12; switch tube 13; second voltage divider unit 14; adjustment unit 15; filter module 2; filter unit 21; overcurrent protection module 3; electrostatic protection module 4; discharge module 5; power supply positive input terminal 61; load positive output terminal 62; power supply negative input terminal 63; load negative output terminal 64. DETAILED DESCRIPTION

[0031] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings and are constructed and operated in specific directions. They are only for the convenience of describing the present technical solution and do not indicate that the devices or components referred to must have specific directions. Therefore, they should not be understood as limiting the present invention.

[0032] It should also be noted that, unless otherwise clearly specified and limited, terms such as "installed", "connected", "connected", "fixed", and "set" should be understood in a broad sense. For example, they can be fixedly connected, detachably connected, or integrated; they can be mechanically connected or electrically connected; they can be directly connected or indirectly connected through an intermediate medium, and they can be internal connections between two elements or interactions between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intervening elements. The terms "first", "second", and "third" are only used to facilitate the description of the present technical solution and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", and "third" can explicitly or implicitly include one or more of these features. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present invention with unnecessary detail.

[0034] The utility model constructs an overvoltage protection module 1, which can not only be used for overvoltage protection, but also play a protective role during power reverse connection.

[0035] In some embodiments, please refer to Figure 1 The overvoltage protection module 1 may include a switch unit 11 and a first voltage dividing unit 12 .

[0036] The switch unit 11 is used to control the on / off state of the circuit between the power input and power output. The switch unit 11 has an input terminal, an output terminal, and a control terminal. When the voltage at its control terminal is greater than or equal to the voltage at its input terminal, the switch unit 11 disconnects the connection between the power supply positive input terminal 61 and the load positive output terminal 62. The input terminal of the switch unit 11 is connected to the power supply positive input terminal 61, the output terminal of the switch unit 11 is connected to the load positive output terminal 62, and the control terminal of the switch unit 11 is connected to the first voltage divider unit 12.

[0037] The first voltage divider unit 12 is used for voltage division and includes a first end for connecting to the positive power input terminal 61, a second end for connecting to the negative power input terminal 63, and a first voltage divider end for outputting a divided power signal (a first voltage divider signal). The control end of the switch unit 11 is connected to the first voltage divider end.

[0038] It is understandable that when the control end of the switch unit 11 receives a divided positive power signal, the voltage at the control end of the switch unit 11 will be lower than the voltage at the input end of the switch unit 11 due to the voltage division of the first voltage divider unit 12, so that the voltage at the control end of the switch unit 11 is lower than the voltage at its input end, so that the positive input end 61 of the power supply and the positive output end 62 of the load can be connected. When the control end of the switch unit 11 receives a divided negative power signal, the positive input end of the power supply is at a negative voltage, and the voltage at the input end of the switch unit 11 is lower than the voltage at the control end of the switch unit 11, so the connection between the positive input end 61 of the power supply and the positive output end 62 of the load is disconnected.

[0039] like Figure 1 As shown, the overvoltage protection module 1 further includes a switch control unit, which is connected to the control end of the switch unit 11 to control the switch unit 11 to be disconnected when the power supply is overvoltage.

[0040] The switch control unit may include a switch tube 13, a second voltage divider unit 14, and an adjustment unit 15. The second voltage divider unit 14 is used for voltage division and has a first end for connecting to the positive power input terminal 61, a second end for connecting to the negative power input terminal 63, and a second voltage divider end for outputting a divided power signal (a second voltage divider signal). The control end of the switch tube 13 is connected to the second voltage divider end of the second voltage divider unit 14 to switch on and off according to the magnitude of the second voltage divider signal. At the same time, the input end of the switch tube 13 is connected to the positive power input terminal 61, and the output end of the switch tube 13 is connected to the control end of the switch unit 11 to connect the control end of the switch unit 11 to the positive power input terminal 61 when the switch tube is turned on. The adjustment unit 15 is connected between the second end of the second voltage divider unit 14 and the negative power input terminal 63 and is used to intervene and adjust the magnitude of the second voltage divider signal when the power supply is overvoltage, so as to turn on the switch tube 13.

[0041] It can be understood that when the power supply is normally connected and overvoltage occurs, the switch tube 13 connects the control end of the switch unit 11 and the positive input end 61 of the power supply under the action of the adjustment unit 15, so that the voltage of the control end of the switch unit 11 is equivalent to the voltage of the input end of the switch unit 11, so the connection between the positive input end 61 of the power supply and the positive output end 62 of the load is disconnected.

[0042] In some embodiments, as Figure 1 As shown, the switch unit 11 may include a MOS transistor Q2, which is a PMOS transistor. That is, the gate (G) of the MOS transistor Q2 is equivalent to the control terminal of the switch unit 11, the source (S) of the MOS transistor Q2 is equivalent to the input terminal of the switch unit 11, and the drain (D) of the MOS transistor Q2 is equivalent to the output terminal of the switch unit 11.

[0043] It can be understood that when the gate of the MOS transistor Q2 is pulled low relative to its source (ie V GS is a negative value), MOS tube Q2 is turned on, allowing current to flow from the drain to the source; therefore, when the power supply is in a normal state, MOS tube Q2 can be turned on. When the power supply is in a reverse state, MOS tube Q2 is turned on because of V GS At the same time, when the power supply is in an overvoltage state, the switch tube 13 is turned on under the action of the adjustment unit 15, and the voltage of the gate of the MOS tube Q2 is the same as the voltage at the source (i.e. V GS =0), so MOS transistor Q2 is turned off. It can be understood that the normal state means that the power supply voltage is within the preset rated range and the power supply polarity is connected correctly. The overvoltage state means that the power supply voltage exceeds the preset threshold. The reverse connection state means that the positive and negative poles of the power supply are reversed.

[0044] In some embodiments, as Figure 1 As shown, the adjustment unit 15 may include a voltage regulator tube D2, the cathode of which is connected between the second end of the second voltage divider unit 14 and the negative power input terminal 63, and the anode of which is connected to the negative power input terminal 63. Meanwhile, the switch tube 13 is a transistor Q1, which is a PNP transistor.

[0045] Understandably, when the power supply is in an overvoltage state, Zener diode D2 breaks down, causing the base of transistor Q1 to be at a low level, turning transistor Q1 on. When the power supply is in a normal state, Zener diode D2 stabilizes the voltage, causing the base of transistor Q1 to be at a high level, turning transistor Q1 off. Furthermore, when the power supply is in a reverse polarity state, Zener diode D2 acts like a normal diode, causing the base of transistor Q1 to be at a high level, turning transistor Q1 off.

[0046] In some embodiments, the second voltage dividing unit 14 may include at least two resistive elements. Figure 1 As shown, the second voltage dividing unit 14 includes a resistor R1 and a resistor R2 connected in series, and the control end of the transistor Q1 is connected between the resistor R1 and the resistor R2.

[0047] In some embodiments, the first voltage dividing unit 12 may include at least two resistive elements. Figure 1 As shown, the first voltage dividing unit 12 includes a resistor R3 and a resistor R4 connected in series, and the control end of the MOS transistor Q2 is connected between the resistor R1 and the resistor R2.

[0048] In summary, the overvoltage protection module 1 is based on the on-off of the switch unit 11 to protect the circuit behind the switch unit 11 during overvoltage and power reverse connection.

[0049] In addition, the present invention also constructs a power protection circuit, which includes the above-mentioned overvoltage protection module 1 and a filter module 2 connected to the rear end of the switch unit 11.

[0050] The filtering module 2 is at least used for filtering. Figure 2 The filtering module 2 may include an electrolytic capacitor C3 and at least one filtering unit 21; the positive electrode of the electrolytic capacitor C3 is connected to the positive input terminal 61 of the power supply, and the negative electrode thereof is connected to the negative output terminal 64 of the load; one end of the filtering unit 21 is connected between the positive input terminal 61 of the power supply and the positive output terminal 62 of the load, and the other end of the filtering unit 21 is connected between the negative input terminal 63 of the power supply and the negative output terminal 64 of the load.

[0051] It can be understood that when the power supply is in a reverse connection state, the switch unit 11 of the overvoltage protection module 1 disconnects the connection between the power supply positive input terminal 61 and the electrolytic capacitor C3, thereby protecting the electrolytic capacitor C3.

[0052] Optionally, the single filter unit 21 may include a common mode inductor, or the single filter unit 21 may be an LC filter unit. Further optionally, the LC filter unit may be an L-type filter unit, a π-type filter unit, or a T-type filter unit, which may be selected according to the input and output impedances. In this embodiment, Figure 2 As shown, the filter module 2 includes two filter units 21, namely a first filter unit and a second filter unit. The first filter unit is a common-mode inductor, and the second filter unit is a π-type filter unit. The π-type filter unit may include an inductor L2, at least one capacitor connected to one end of the inductor L2, and at least one capacitor connected to the other end of the inductor L2.

[0053] In some embodiments, as Figure 2As shown, the power protection circuit may further include a TVS tube D1 connected to the front end of the overvoltage protection module 1, wherein the cathode of the TVS tube D1 is connected between the positive input terminal 61 of the power supply and the positive output terminal 62 of the load, and the anode of the TVS tube D1 is connected between the negative input terminal 63 of the power supply and the negative output terminal 64 of the load.

[0054] As can be understood, TVS diode D1 can provide overvoltage protection during power supply overvoltage conditions. Furthermore, when the power supply is reverse polarity, TVS diode D1 can function as a common diode, forming a loop from the negative power supply input terminal 63, TVS diode D1, and the positive power supply input terminal 61. This effectively prevents power from flowing into the circuitry behind TVS diode D1, providing protection.

[0055] In some embodiments, as Figure 2 As shown, the power protection circuit may further include an overcurrent protection module 3 connected to the front end of the TVS tube D1. The overcurrent protection module 3 may be connected between the negative input terminal 63 of the power supply and the negative output terminal 64 of the load to provide overcurrent protection for its back-end circuit.

[0056] Optionally, the overcurrent protection module 3 may include a fuse F1 .

[0057] In some embodiments, as Figure 2 As shown, the power protection circuit may further include an electrostatic protection module 4 connected to the front end of the TVS tube D1, wherein one end of the electrostatic protection module 4 is connected between the positive input terminal 61 of the power supply and the positive output terminal 62 of the load, and the other end is connected between the negative input terminal 63 of the power supply and the negative output terminal 64 of the load, so as to reduce the damage caused by electrostatic discharge to the back-end circuit of the electrostatic protection module 4.

[0058] Optionally, the electrostatic protection module 4 may include at least one capacitive element. For example, the electrostatic protection module 4 may include two capacitors connected in series, namely capacitor C1 and capacitor C2, wherein the end of capacitor C1 away from capacitor C2 is connected between the positive input terminal 61 of the power supply and the positive output terminal 62 of the load, and the end of capacitor C2 away from capacitor C1 is connected between the negative input terminal 63 of the power supply and the negative output terminal 64 of the load.

[0059] In some embodiments, as Figure 2 As shown, the power protection circuit may further include a discharge module 5 connected to the rear end of the filter module 2, one end of the discharge module 5 being connected to the filter module 2, and the other end being connected to the negative output terminal 64 of the load, so as to release the stored electricity in the capacitor of the filter module 2 to the casing ground, thereby preventing the step-like level when power is turned on again from affecting the working state of the subsequent load.

[0060] Optionally, the discharge module 5 may include at least one resistive element. In this embodiment, the discharge module 5 includes a resistor R5.

[0061] The following Figure 2 The complete power supply protection circuit shown in the figure is used as an example to illustrate the effect of this power supply protection circuit. The following assumes that the power supply input voltage range is less than 32V and greater than 8V, which is the rated range of the power supply.

[0062] When the power input is less than 32V and greater than 8V, the power supply is in a normal state. The TVS tube D1 shows the characteristics of a diode and does not work. After the power input passes through the resistors R1, R2 and the voltage regulator D2, the transistor Q1 is in a cut-off state. At the same time, after the power input is divided by the resistors R3 and R4, the voltage at the gate of the MOS tube Q2 is stabilized to be lower than the power input (for example, if the resistance values ​​of the resistors R3 and R4 are equal, the voltage at the gate of the MOS tube Q2 is stabilized to half of the power input), so that V GS When the voltage is less than 0, the MOS tube Q2 is in the on state. The power input passes through the TVS tube D1 and the overvoltage protection module 1 with a very small voltage drop, and then passes through the filter module 2 and the discharge module 5 to supply power to the load end. In addition, when the load is not needed, the discharge module 5 releases the stored charge in the capacitor of the filter module 2 to the chassis ground.

[0063] When the power input is greater than 33V, the power supply is in an overvoltage state. When the power input passes through the TVS tube D1, the TVS tube D1 works, instantly releasing the overvoltage in the form of power, stabilizing the voltage in a low range, and protecting the back-end circuit. When the overvoltage lasts for a long time, the overvoltage protection module 1 takes effect. Under the action of the voltage regulator tube D2, the transistor Q1 meets the conduction condition, and the V GS When the voltage drops to 0, MOS tube Q2 turns off, thus protecting the back-end circuit of the overvoltage protection module 1. It should be noted that at this time, the overvoltage acts on resistors R1, R2, R3, and R4. By selecting resistors with large resistance values, the front-end circuit can be protected from damage.

[0064] When the power input is reversed, that is, the power supply is in a reverse connection state, when the power input passes through the TVS tube D1 from the negative input terminal 63 of the power supply, the TVS tube D1 will perform the conduction function of a diode, and the reverse current can pass through the TVS tube D1. After a small voltage drop, the reverse current returns to the positive input terminal 61 of the power supply through the fuse F1. At this time, if the current is too large, the fuse F1 can be turned off to protect the power supply terminal. At the same time, in the overvoltage protection module 1, the voltage regulator tube D2 also performs the conduction function of a diode, and the transistor Q1 meets the cut-off condition, so that V GSIf the voltage is greater than 0, MOS transistor Q2 is cut off. Since the return path is blocked, the back-end circuitry of overvoltage protection module 1 (such as polarity components such as electrolytic capacitor C3 and the load terminal) is protected. This shows that polarity components such as electrolytic capacitor C3 and the load terminal receive dual reverse polarity protection from the front end, ensuring that they will not be damaged when reversely connected to a large polarity voltage. It should be noted that due to the diode characteristics of TVS diode D1, the maximum voltage across electrolytic capacitor C3 will not exceed 0.7V, preventing damage.

[0065] In addition, when the power input polarity is normal but there is overcurrent (such as short circuit), the fuse F1 can also automatically burn out to protect the downstream circuit of the fuse F1.

[0066] In summary, this power protection circuit provides dual overvoltage protection and reverse polarity protection. This protects the load while also preventing damage to the power supply and the power protection circuit itself from reverse polarity. This provides excellent protection even in extreme environments such as prolonged reverse polarity and / or overvoltage. Furthermore, this power protection circuit offers additional protection features, including electrostatic discharge protection, overcurrent protection, and charge discharge protection, providing comprehensive protection for the power input circuit of electronic devices.

[0067] This power protection circuit can be applied to onboard electronic devices, such as OBU devices, to protect the power input circuit of the onboard electronic devices. Of course, the power protection circuit is not necessarily limited to onboard electronic devices and can also be applied to other electronic devices, and there is no specific limitation here. For example, the power protection circuit can also be applied to roadside equipment, such as RSU units, payment machines, etc.

[0068] Based on this, the present invention also constructs an on-vehicle electronic device, which includes a load element (not shown) and the above-mentioned power protection circuit; the power protection circuit is connected to the load element to transfer the input power to the load element.

[0069] It can be understood that the above embodiments only express the preferred implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, all of which fall within the scope of protection of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of coverage of the claims of the present invention.

Claims

1. An overvoltage protection module, characterized in that: include: A first voltage dividing unit (12) is provided with a first end and a second end for respectively connecting to a power supply positive input end (61) and a power supply negative input end (63), and a first voltage dividing end for outputting a first voltage dividing signal; A switch unit (11) is used to control the on / off of a circuit between a power input and an output; the switch unit (11) is provided with an input end and an output end respectively connected to a power positive input end (61) and a load positive output end (62), and a control end connected to the first voltage divider end; the switch unit (11) is configured to be disconnected when the voltage at its control end is greater than or equal to the voltage at its input end; A second voltage dividing unit (14) is provided with a first end and a second end for respectively connecting to a positive power input terminal (61) and a negative power input terminal (63), and a second voltage dividing terminal for outputting a second voltage dividing signal; A switch tube (13) is used to connect the control end of the switch unit (11) and the positive input end (61) of the power supply when it is turned on; the control end of the switch tube (13) is connected to the second voltage dividing end to switch on and off according to the second voltage dividing signal; An adjustment unit (15) is connected to the second end of the second voltage dividing unit (14) to adjust the magnitude of the second voltage dividing signal to turn on the switch tube (13) when the power supply is over-voltage.

2. The overvoltage protection module according to claim 1, characterized in that: The switch unit (11) comprises a MOS transistor Q2, and the MOS transistor Q2 is a PMOS transistor.

3. The overvoltage protection module according to claim 1, characterized in that: The adjustment unit (15) includes a voltage regulator tube D2, the cathode of the voltage regulator tube D2 is connected to the second end of the second voltage divider unit (14), and the anode of the voltage regulator tube D2 is used to connect to the negative input terminal (63) of the power supply; The switch tube (13) is a transistor Q1, and the transistor Q1 is a PNP transistor.

4. A power protection circuit, comprising a filter module (2), wherein the filter module (2) comprises an electrolytic capacitor C3, wherein the positive electrode of the electrolytic capacitor C3 is connected to the positive input terminal (61) of the power supply, and the negative electrode thereof is connected to the negative output terminal (64) of the load, wherein: The power protection circuit further comprises an overvoltage protection module according to any one of claims 1 to 3, and the overvoltage protection module is connected to the front end of the filter module (2).

5. The power protection circuit according to claim 4, characterized in that: The power protection circuit further includes a TVS tube D1 connected to the front end of the overvoltage protection module, wherein the cathode of the TVS tube D1 is connected between the positive input terminal (61) of the power supply and the positive output terminal (62) of the load, and the anode of the TVS tube D1 is connected between the negative input terminal (63) of the power supply and the negative output terminal (64) of the load.

6. The power protection circuit according to claim 5, characterized in that: The power protection circuit further comprises a fuse F1 connected to the front end of the TVS tube D1, wherein the fuse F1 is connected between the positive input terminal (61) of the power supply and the positive output terminal (62) of the load.

7. The power protection circuit according to claim 5, characterized in that: The power protection circuit further comprises an electrostatic protection module (4) connected to the front end of the TVS tube D1; the electrostatic protection module (4) comprises a plurality of capacitive elements connected in series and connected between the positive input terminal (61) of the power supply and the negative input terminal (63) of the power supply.

8. The power protection circuit according to claim 4, wherein: The power protection circuit further comprises a discharge module (5) connected to the rear end of the filter module (2); the discharge module (5) comprises at least one resistive element; one end of the resistive element is connected to the filter module (2), and the other end is connected to the load negative output terminal (64).

9. The power protection circuit according to claim 4, characterized in that: The power protection circuit further includes an electrostatic protection module (4); the electrostatic protection module (4) includes a capacitor C1 and a capacitor C2 connected in series, connected between the positive input terminal (61) of the power supply and the negative input terminal (63) of the power supply; The power protection circuit further includes a fuse F1, which is connected between the positive input terminal (61) of the power supply and the overvoltage protection module; The power protection circuit further includes a TVS tube D1 connected between the fuse F1 and the overvoltage protection module, wherein the cathode of the TVS tube D1 is connected between the positive input terminal (61) of the power supply and the positive output terminal (62) of the load, and the anode of the TVS tube D1 is connected between the negative input terminal (63) of the power supply and the negative output terminal (64) of the load; The power protection circuit further comprises a discharge module (5) connected to the rear end of the filter module (2); the discharge module (5) comprises a resistor R5; one end of the resistor R5 is connected to the filter module (2), and the other end thereof is connected to the load negative output terminal (64).

10. An in-vehicle electronic device comprising a load element, characterized in that: It also includes the power protection circuit according to any one of claims 4 to 9; the power protection circuit is connected to the load element.

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