Pre-charging circuit, vehicle-mounted power amplifier and vehicle

Abstract

The utility model provides a pre-charging circuit, a vehicle-mounted power amplifier and a vehicle, and relates to the technical field of circuits, and the pre-charging circuit comprises a first switch unit, a second switch unit, a pre-charging resistor and a control device. The first switch unit is connected with the pre-charging resistor in series, the control device sequentially sends a first conduction signal to the first switch unit, sends a second conduction signal to the second switch unit and sends a turn-off signal to the first switch unit, the current limiting capacity is good, surge current can be effectively restrained, and the service life of the device is prolonged. The risk that the power supply module and the electronic equipment are damaged due to overlarge surge current is avoided, and the risk that each switch unit is burnt down is also reduced. Moreover, the pre-charging circuit can reduce the specification requirement of the second switch unit, can save the cost, and is higher in practicability.

Description

Technical Field

[0001] This utility model relates to the field of circuit technology, and in particular to a pre-charging circuit, an on-board power amplifier, and a vehicle. Background Technology

[0002] As new energy vehicles, autonomous driving, and in-vehicle information systems mature, drivers and passengers have increasingly higher demands for the sound quality of in-vehicle audio-visual entertainment systems, leading to a rise in speaker channels to as many as 32 channels or more. With this increase in speaker channels, the in-vehicle power amplifier needs to support greater output power and more refined sound, requiring more capacitors in the preamplifier stage. This can result in excessive inrush current, potentially damaging both the car battery and the power amplifier. Furthermore, current power supply architectures utilize electronic fuses, which have lower current draw than traditional fuses, making them highly susceptible to burnout or accidental tripping by large inrush currents.

[0003] Current mainstream solutions limit inrush current using MOSFET soft-start circuits, with millisecond-level soft-start suppressing inrush current. However, the current-limiting capability of MOSFET soft-start circuits is limited. Currently, multi-channel capacitors have capacitances as high as 20000uF, and even with a soft-start circuit achieving tens of milliseconds, the inrush current can still reach 200A-300A. Furthermore, excessive inrush current can cause the MOSFET to operate in the variable resistance region with excessive instantaneous power, potentially burning out the MOSFET. Utility Model Content

[0004] This invention provides a pre-charging circuit, an on-board power amplifier, and a vehicle to address the deficiencies in related technologies.

[0005] This utility model provides a pre-charging circuit, including: a first switching unit, a second switching unit, a pre-charging resistor, and a control device;

[0006] The first switching unit is connected in series with the pre-charge resistor. The first switching unit is used to connect to the power supply module, and the pre-charge resistor is used to connect to the electrical load.

[0007] The second switching unit is used to connect to the power supply module and the electrical load respectively;

[0008] The control device is connected to the first switch unit and the second switch unit respectively, and is used to send a first conduction signal to the first switch unit and a second conduction signal to the second switch unit in sequence, and send a turn-off signal to the first switch unit.

[0009] According to the pre-charging circuit provided by this utility model, the first switching unit includes a first MOS transistor, which is either a first NMOS transistor or a first PMOS transistor.

[0010] The drain of the first NMOS transistor is connected to the power supply module, the gate of the first NMOS transistor is connected to the control device, and the source of the first NMOS transistor is connected to the electrical load.

[0011] The source of the first PMOS transistor is connected to the power supply module, the gate of the first PMOS transistor is connected to the control device, and the drain of the first PMOS transistor is connected to the pre-charge resistor.

[0012] According to the present invention, a pre-charging circuit is provided, wherein the control device includes a first transistor, a first resistor, and a microcontroller unit;

[0013] The first resistor is connected between the power supply module and the gate of the first MOS transistor, the collector of the first transistor is connected to the gate of the first MOS transistor, the base of the first transistor is connected to the microcontroller unit, and the emitter of the first transistor is grounded.

[0014] The microcontroller unit is used to control the base of the first transistor to generate the first turn-on signal and the turn-off signal.

[0015] According to the pre-charging circuit provided by this utility model, the second switching unit includes a second MOS transistor, which is a second NMOS transistor or a second PMOS transistor;

[0016] The drain of the second NMOS transistor is connected to the power supply module, the gate of the second NMOS transistor is connected to the control device, and the source of the second NMOS transistor is connected to the electrical load.

[0017] The source of the second PMOS transistor is connected to the power supply module, the gate of the second PMOS transistor is connected to the control device, and the drain of the second PMOS transistor is connected to the electrical load.

[0018] According to the present invention, a pre-charging circuit is provided, wherein the control device includes a second transistor, a second resistor, and a microcontroller unit;

[0019] The second resistor is connected between the power supply module and the gate of the second MOS transistor, the collector of the second transistor is connected to the gate of the second MOS transistor, the base of the second transistor is connected to the microcontroller unit, and the emitter of the second transistor is grounded.

[0020] The microcontroller unit is used to control the base of the second transistor to generate the second conduction signal.

[0021] According to the pre-charging circuit provided by this utility model, the transmission time interval between the first conduction signal and the second conduction signal is greater than or equal to 500 milliseconds.

[0022] According to the pre-charging circuit provided by this utility model, the second turn-on signal and the turn-off signal are sent simultaneously, or the second turn-on signal is sent after the turn-off signal.

[0023] According to the present invention, the pre-charging resistor has a resistance value of 5Ω.

[0024] This utility model also provides a vehicle-mounted power amplifier, including an electrical load and the aforementioned pre-charging circuit; the power supply module is a vehicle-mounted power supply module.

[0025] This utility model also provides a vehicle, including an on-board power supply module and the aforementioned on-board power amplifier.

[0026] This utility model provides a pre-charging circuit, an on-board power amplifier, and a vehicle. The pre-charging circuit includes a first switching unit, a second switching unit, a pre-charging resistor, and a control device. By connecting the first switching unit and the pre-charging resistor in series, the control device sequentially sends a first turn-on signal to the first switching unit and a second turn-on signal to the second switching unit, and also sends a turn-off signal to the first switching unit. This provides good current limiting capability, effectively suppressing inrush current and avoiding the risk of damage to the power supply module and electronic equipment due to excessive inrush current, while also reducing the risk of burnout of each switching unit. Furthermore, this pre-charging circuit reduces the specification requirements for the second switching unit, saving costs and demonstrating high practicality. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this utility model or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of an existing MOSFET soft-start circuit used in automotive power amplifiers.

[0029] Figure 2 This is a waveform diagram of the surge current in an existing MOSFET soft-start circuit used in automotive power amplifiers.

[0030] Figure 3This is one of the structural schematic diagrams of the pre-charging circuit provided by this utility model.

[0031] Figure 4 This is the second schematic diagram of the pre-charging circuit provided by this utility model.

[0032] Figure 5 This is the third schematic diagram of the pre-charging circuit provided by this utility model.

[0033] Figure 6 This is the fourth schematic diagram of the pre-charging circuit provided by this utility model.

[0034] Figure 7 This is the fifth schematic diagram of the pre-charging circuit provided by this utility model.

[0035] Figure 8 This is a schematic diagram of the gate voltage waveform and surge current waveform of the second PMOS transistor in the pre-charging circuit provided by this utility model when the second switching unit includes the second PMOS transistor.

[0036] Figure 9 This is a schematic diagram of the gate voltage waveforms of the first PMOS transistor and the second PMOS transistor in the pre-charging circuit provided by this utility model, where the first switching unit includes a first PMOS transistor and the second switching unit includes a second PMOS transistor.

[0037] Figure 10 This is a schematic diagram of the structure of the vehicle-mounted power amplifier provided by this utility model.

[0038] Figure 11 This is a structural schematic diagram of the vehicle provided by this utility model. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0040] Existing MOSFET soft-start circuits used in automotive power amplifiers, such as Figure 1 As shown, the system includes a PMOS transistor Q0, a resistor R0, a capacitor C0, and a diode D0. The drain D of the PMOS transistor Q0 is connected to the automotive battery 11, the gate G of the PMOS transistor Q0 is grounded through the resistor R0, and the source S of the PMOS transistor Q0 is connected to the electrical load 121 of the on-board power amplifier 12. The capacitor C0 and the diode D0 are connected in parallel between the source S and the gate G of the PMOS transistor Q0.

[0041] like Figure 2 As shown, the current limiting capability of existing MOSFET soft-start circuits is limited. Even after 600ms of soft start, a surge current of up to 200A-300A will still occur. This will not only damage the car battery and the vehicle power amplifier, but also cause the instantaneous power of the MOSFET to be too high when it is operating in the variable resistance region, thus burning out the MOSFET.

[0042] Based on this, this utility model embodiment provides a pre-charging circuit, which can be applied to electronic devices that need to be connected to an external power supply module for power supply, such as vehicle power amplifiers and other electronic devices. It is understood that this pre-charging circuit acts as a front-end circuit connecting the power supply module and the electrical load in the electronic device, thereby reducing the inrush current generated at the moment the power supply module and the electrical load of the electronic device are connected.

[0043] Figure 3 This is a schematic diagram of the pre-charging circuit provided in the embodiment of this utility model, as shown below. Figure 3 As shown, the pre-charging circuit includes: a first switching unit 21, a second switching unit 22, a pre-charging resistor R1, and a control device 23;

[0044] The first switching unit 21 is connected in series with the pre-charging resistor R1. The first switching unit 21 is used to connect to the power supply module 24, and the pre-charging resistor R1 is used to connect to the electrical load 25.

[0045] The second switching unit 22 is used to connect to the power supply module 24 and the electrical load 25 respectively;

[0046] The control device 23 is connected to the first switch unit 21 and the second switch unit 22 respectively, and is used to send a first conduction signal to the first switch unit 21 and a second conduction signal to the second switch unit 22 in sequence, and send a turn-off signal to the first switch unit 21.

[0047] Specifically, in the pre-charging circuit provided in this embodiment of the present invention, the first switching unit 21 and the second switching unit 22 can be components with control circuit switching functions, and can each include any one of MOSFETs, insulated-gate bipolar transistors (IGBTs), relays, thyristors, and bipolar junction transistors (BJTs). For example, both the first switching unit 21 and the second switching unit 22 can be MOSFETs, and the models can be the same or different. They can both be PMOS transistors or NMOS transistors, or one can be a PMOS transistor and the other an NMOS transistor; no specific limitation is made here.

[0048] Both the first switching unit 21 and the second switching unit 22 can be controlled to be turned on or off by the control signal of the control device 23, thereby realizing the circuit switching.

[0049] The control signals of the control device 23 may include turn-on signals and turn-off signals. The control device 23 may first send a first turn-on signal to the first switching unit 21 to turn on the first switching unit 21. The power supply module 24 can then supply power to the electrical load 25 through the first switching unit 21 and the pre-charge resistor R1. Since the first switching unit 21 is connected in series with the pre-charge resistor R1, the pre-charge resistor R1 can limit the current, thereby effectively suppressing surge current.

[0050] It's understandable that electronic devices perform some system configurations when they start working, without requiring excessive current. Therefore, even if the pre-charge resistor has a large resistance value, it won't cause an excessive voltage drop, and the electronic device can still maintain normal operation.

[0051] The surge current suppression effect is determined by the transmission time interval between the first and second conduction signals and the resistance value of the pre-charging resistor R1. This transmission time interval can be determined by the capacitance value in the electrical load; it is the duration for which the voltage across the capacitor in the electrical load can reach a specified value using the first switching unit 21 and the pre-charging resistor R1. This specified value can be the operating voltage of the electrical load and its capacitor, or a preset multiple of that operating voltage, where the preset multiple is less than 1.

[0052] When the first switching unit 21 is turned on, the control device 23 can continue to send a second turn-on signal to the second switching unit 22, so that the second switching unit 22 is turned on. The power supply module 24 can supply power to the electrical load 25 through the second switching unit 22, and continuously provide working current to the electrical load 25.

[0053] The control device 23 can also send a shutdown signal to the first switch unit 21 to shut down the first switch unit 21, so that the power supply module 24 supplies power to the electrical load 25 only through the second switch unit 22.

[0054] This embodiment of the invention provides a pre-charging circuit, including: a first switching unit, a second switching unit, a pre-charging resistor, and a control device. By connecting the first switching unit and the pre-charging resistor in series, the control device sequentially sends a first turn-on signal to the first switching unit and a second turn-on signal to the second switching unit, and also sends a turn-off signal to the first switching unit. This provides good current limiting capability, effectively suppressing inrush current and avoiding the risk of damage to the power supply module and electronic equipment due to excessive inrush current, while also reducing the risk of burnout of each switching unit. Furthermore, this pre-charging circuit can reduce the specification requirements of the second switching unit, saving costs and demonstrating high practicality.

[0055] Based on the above embodiments, the first switching unit includes a first MOS transistor, which is either a first NMOS transistor or a first PMOS transistor;

[0056] The drain of the first NMOS transistor is connected to the power supply module, the gate of the first NMOS transistor is connected to the control device, and the source of the first NMOS transistor is connected to the electrical load.

[0057] The source of the first PMOS transistor is connected to the power supply module, the gate of the first PMOS transistor is connected to the control device, and the drain of the first PMOS transistor is connected to the pre-charge resistor.

[0058] Specifically, since a PMOS transistor conducts when its gate is low and turns off when its gate is high, when the first MOS transistor is a PMOS transistor, the first turn-on signal output by the control device is low, and the turn-off signal is high. Similarly, since an NMOS transistor conducts when its gate is high and turns off when its gate is low, when the first MOS transistor is an NMOS transistor, the first turn-on signal output by the control device is high, and the turn-off signal is low. Using the first MOS transistor to control the circuit's on / off state results in simple control logic, a simple connection structure, and low cost.

[0059] Based on the above embodiments, the second switching unit includes a second MOS transistor, which is either a second NMOS transistor or a second PMOS transistor;

[0060] The drain of the second NMOS transistor is connected to the power supply module, the gate of the second NMOS transistor is connected to the control device, and the source of the second NMOS transistor is connected to the electrical load.

[0061] The source of the second PMOS transistor is connected to the power supply module, the gate of the second PMOS transistor is connected to the control device, and the drain of the second PMOS transistor is connected to the electrical load.

[0062] Specifically, when the second MOSFET is a second PMOS transistor, the second turn-on signal output by the control device is low, and the turn-off signal is high. When the second MOSFET is a second NMOS transistor, the second turn-on signal output by the control device is high, and the turn-off signal is low. Using the second MOSFET to control the circuit's on / off state results in simple control logic, a simple connection structure, and low cost.

[0063] like Figure 4As shown, the first switching unit includes a first PMOS transistor Q11, and the second switching unit includes a second NMOS transistor Q12. The source S of the first PMOS transistor Q11 is connected to the power supply module 24, the gate G of the first PMOS transistor Q11 is connected to the control device 23, and the drain D of the first PMOS transistor Q11 is connected to the pre-charge resistor R1. The drain D of the second NMOS transistor Q12 is connected to the power supply module 24, the gate G of the second NMOS transistor Q12 is connected to the control device 23, and the source S of the second NMOS transistor Q12 is connected to the electrical load 25.

[0064] like Figure 5 As shown, the first switching unit includes a first PMOS transistor Q11 and the second switching unit includes a second PMOS transistor Q13. The source S of the second PMOS transistor Q13 is used to connect to the power supply module 24, the gate G of the second PMOS transistor Q13 is connected to the control device 23, and the drain D of the second PMOS transistor Q13 is used to connect to the electrical load 25.

[0065] Based on the above embodiments, the control device includes a first transistor, a first resistor, and a microcontroller unit;

[0066] The first resistor is connected between the power supply module and the gate of the first MOSFET. The collector of the first transistor is connected to the gate G of the first MOSFET. The base of the first transistor is connected to the microcontroller unit. The emitter of the first transistor is grounded.

[0067] The microcontroller unit is used to control the base of the first transistor to generate a first turn-on signal and a turn-off signal.

[0068] Specifically, in this embodiment of the invention, the base of the first transistor is connected to the first general-purpose input / output (GPIO) interface of the microcontroller unit. Since the output voltage of the microcontroller unit, i.e., the high level of the output, is usually 3.3V or 5V, while the gate voltage required for the MOSFET to conduct is usually higher, the first transistor is introduced to convert the output voltage of the microcontroller unit into a first conduction signal, thereby controlling the first MOSFET to conduct.

[0069] If the microcontroller outputs a high level, the first transistor is turned on, and the gate and collector of the first MOS transistor are both at a low level. If the first MOS transistor is a first PMOS transistor, it is turned on; if the first MOS transistor is a first NMOS transistor, it is turned off.

[0070] If the microcontroller outputs a low level, the first transistor is turned off, and the gate of the first MOSFET is connected to the power supply module through the first resistor. Both the gate of the first MOSFET and the collector of the first transistor are at a high level. If the first MOSFET is a first PMOS transistor, it is turned off; if the first MOSFET is a first NMOS transistor, it is turned on.

[0071] In this embodiment of the invention, by combining the first transistor, the first resistor, and the microcontroller unit, the switching control of the first MOS transistor can be realized. The structure is simple and the control principle is easy to implement.

[0072] Based on the above embodiments, the control device includes a second transistor, a second resistor, and a microcontroller unit;

[0073] The second resistor is connected between the power supply module and the gate of the second MOSFET. The collector of the second transistor is connected to the gate of the second MOSFET. The base of the second transistor is connected to the microcontroller unit. The emitter of the second transistor is grounded.

[0074] The microcontroller unit is used to control the base of the second transistor to generate a second conduction signal.

[0075] Specifically, in this embodiment of the invention, the base of the second transistor is connected to the second general-purpose input / output interface of the microcontroller. Since the output voltage of the microcontroller, i.e., the high-level output, is typically 3.3V or 5V, while the gate voltage required for the MOSFET to conduct is typically higher, a second transistor is introduced to convert the output voltage of the microcontroller into a second conduction signal, thereby controlling the second MOSFET to conduct.

[0076] If the microcontroller outputs a high level, the second transistor is turned on, and the gate of the second MOS transistor and the collector of the second transistor are both at a low level. If the second MOS transistor is a second PMOS transistor, it is turned on; if the second MOS transistor is a second NMOS transistor, it is turned off.

[0077] If the microcontroller outputs a low level, the second transistor is turned off. The gate of the second MOSFET is connected to the power supply module through the second resistor. Both the gate of the second MOSFET and the collector of the second transistor are at a high level. If the second MOSFET is a second PMOS transistor, it is turned off; if the second MOSFET is a second NMOS transistor, it is turned on.

[0078] In this embodiment of the invention, by combining a second transistor, a second resistor, and a microcontroller unit, the switching control of the second MOSFET can be realized. The structure is simple and the control principle is easy to implement.

[0079] like Figure 6As shown, the first switching unit includes a first PMOS transistor Q11, and the second switching unit includes a second NMOS transistor Q12. The source S of the first PMOS transistor Q11 is connected to the power supply module 24. The gate G of the first PMOS transistor Q11 is connected to the collector of the first transistor Q21 and is connected to the power supply module 24 through the first resistor R2. The drain D of the first PMOS transistor Q11 is connected to the pre-charge resistor R1. The drain D of the second NMOS transistor Q12 is connected to the power supply module 24. The gate G of the second NMOS transistor Q12 is connected to the collector of the second transistor Q22 and is connected to the power supply module 24 through the second resistor R3. The source S of the second NMOS transistor Q12 is connected to the electrical load 25. The bases of both the first transistor Q21 and the second transistor Q22 are connected to the microcontroller unit 23. The emitters of both the first transistor Q21 and the second transistor Q22 are grounded.

[0080] Based on the above embodiments, such as Figure 7 As shown, it also includes capacitor C1, which is connected in parallel with the first resistor R2.

[0081] Based on the above embodiments, such as Figure 7 As shown, it also includes capacitor C2, diode D2 and resistor R4. Capacitor C2, diode D2 and resistor R4 are all connected in parallel between the gate G and source S of the second NMOS transistor Q12.

[0082] Based on the above embodiments, such as Figure 7 As shown, it also includes capacitors C20 and C21, which are connected in parallel to the output line of the power supply module and grounded to achieve filtering. Here, the capacitance value of capacitor C20 can be 100nF, and the capacitance value of capacitor C21 can be 47nF.

[0083] Based on the above embodiments, the transmission time interval between the first conduction signal and the second conduction signal is greater than or equal to 500 milliseconds, so as to ensure that the capacitor voltage of the electrical load can be greatly improved through the first switching unit and the pre-charge resistor, thereby achieving effective suppression of surge current.

[0084] Based on the above embodiment, the resistance value of the pre-charge resistor is 5Ω. When the second switching unit includes a second PMOS transistor, as... Figure 8As shown, the green line represents the gate voltage waveform of the second PMOS transistor, and the blue line represents the surge current waveform. With a transmission time interval of 500 milliseconds or more between the first and second turn-on signals, and a pre-charge resistor of 5Ω, the surge current generated when the first switching unit turns on in approximately 0.1 seconds is less than 3A. When the second PMOS transistor turns on from off in approximately 0.6 to 0.61 seconds, the surge current can still be effectively suppressed to within 3A. Furthermore, since the impact of the surge current on the instantaneous power is not a major concern, the power and current specifications of the first and second switching units can be reduced accordingly. Moreover, for the power supply scheme of the electronic fuse, this effectively reduces the surge current, thereby reducing the risk of electronic fuse failure.

[0085] Based on the above embodiments, the second turn-on signal and the turn-off signal are sent simultaneously, or the second turn-on signal is sent after the turn-off signal.

[0086] Based on the above embodiments, in the case where the first switching unit includes a first PMOS transistor and the second switching unit includes a second PMOS transistor, such as Figure 9 As shown, the green line represents the gate voltage waveform of the first PMOS transistor, and the blue line represents the gate voltage waveform of the second PMOS transistor. The first PMOS transistor turns on first, then the second PMOS transistor turns on, and then the first PMOS transistor turns off, with the second PMOS transistor continuously providing operating current to the electrical load.

[0087] like Figure 10 As shown, based on the above embodiments, this utility model provides a vehicle power amplifier, including an electrical load 101 and a pre-charging circuit 102 provided in the above embodiments; the power supply module connected to the pre-charging circuit 102 is a vehicle power supply module 103. The vehicle power supply module 103 can be a car battery.

[0088] The vehicle power amplifier provided in this embodiment of the present invention can avoid generating large surge currents when connected to the vehicle power supply module, thus preventing damage to itself and other components.

[0089] like Figure 11 As shown, based on the above embodiments, this utility model provides a vehicle, including an on-board power supply module 110 and an on-board power amplifier 111 provided in the above embodiments.

[0090] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A pre-charge circuit, comprising: include: The system comprises a first switching unit, a second switching unit, a pre-charge resistor, and a control device. The first switching unit is connected in series with the pre-charge resistor. The first switching unit is used to connect to the power supply module, and the pre-charge resistor is used to connect to the electrical load. The second switching unit is used to connect to the power supply module and the electrical load respectively; The control device is connected to the first switch unit and the second switch unit respectively, and is used to send a first conduction signal to the first switch unit and a second conduction signal to the second switch unit in sequence, and to send a turn-off signal to the first switch unit.

2. The pre-charge circuit of claim 1, wherein, The first switching unit includes a first MOS transistor, which is either a first NMOS transistor or a first PMOS transistor; The drain of the first NMOS transistor is connected to the power supply module, the gate of the first NMOS transistor is connected to the control device, and the source of the first NMOS transistor is connected to the electrical load. The source of the first PMOS transistor is connected to the power supply module, the gate of the first PMOS transistor is connected to the control device, and the drain of the first PMOS transistor is connected to the pre-charge resistor.

3. The pre-charge circuit of claim 2, wherein, The control device includes a first transistor, a first resistor, and a microcontroller unit; The first resistor is connected between the power supply module and the gate of the first MOS transistor, the collector of the first transistor is connected to the gate of the first MOS transistor, the base of the first transistor is connected to the microcontroller unit, and the emitter of the first transistor is grounded. The microcontroller unit is used to control the base of the first transistor to generate the first turn-on signal and the turn-off signal.

4. The pre-charge circuit of claim 1, wherein, The second switching unit includes a second MOS transistor, which is either a second NMOS transistor or a second PMOS transistor; The drain of the second NMOS transistor is connected to the power supply module, the gate of the second NMOS transistor is connected to the control device, and the source of the second NMOS transistor is connected to the electrical load. The source of the second PMOS transistor is connected to the power supply module, the gate of the second PMOS transistor is connected to the control device, and the drain of the second PMOS transistor is connected to the electrical load.

5. The pre-charge circuit of claim 4, wherein, The control device includes a second transistor, a second resistor, and a microcontroller unit; The second resistor is connected between the power supply module and the gate of the second MOS transistor, the collector of the second transistor is connected to the gate of the second MOS transistor, the base of the second transistor is connected to the microcontroller unit, and the emitter of the second transistor is grounded. The microcontroller unit is used to control the base of the second transistor to generate the second conduction signal.

6. The pre-charge circuit of any one of claims 1-5, wherein, The time interval between the transmission of the first conduction signal and the second conduction signal is greater than or equal to 500 milliseconds.

7. The pre-charge circuit of any one of claims 1-5, wherein, The second turn-on signal is sent simultaneously with the turn-off signal, or the second turn-on signal is sent after the turn-off signal.

8. The pre-charge circuit of any one of claims 1-5, wherein, The resistance of the pre-charge resistor is 5Ω.

9. A vehicle-mounted power amplifier, characterized by comprising: Includes electrical loads and a pre-charging circuit as described in any one of claims 1-8; The power supply module is a vehicle-mounted power supply module.

10. A vehicle characterized by comprising: The vehicle-mounted power amplifier comprises a vehicle-mounted power supply module and the vehicle-mounted power amplifier as claimed in claim 9.

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