Automobile power supply charging circuit and automobile power supply system

Abstract

This application relates to the field of power electronics technology, and particularly to an automotive power supply charging circuit and an automotive power supply system, including: first and second voltage detection modules, a DC-DC conversion module, a control module, first and second dual-selection switch modules, and first, second, and third terminals; the first dual-selection switch module includes a first relay, the second dual-selection switch module includes a second relay, and both the first relay and the second relay include a dual-selection switch composed of a moving contact, a normally open static contact, and a normally closed static contact. When the control module receives a reverse charging instruction and the real-time voltages of the first battery and the second battery meet the preset conditions, the control module controls the coils of the first and second relays to be energized, so that the output voltage of the first battery is output to the input terminal of the second battery after passing through the DC-DC conversion module, thereby charging the second battery in a timely and convenient manner and solving the problem that it is relatively troublesome to charge the second battery.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and particularly to an automotive power charging circuit and an electric vehicle power system. Background Art

[0002] Generally, an automotive power system mainly includes a generator battery, a generator, a voltage regulator, etc. The direct current required by the electrical equipment of the vehicle is provided by the generator or the generator battery. When the vehicle is started, the generator starts to work, and at the same time, it charges the generator battery and supplies power to the in-vehicle electrical equipment. The starting process of the vehicle is achieved by the generator battery providing a starting current for the vehicle starter, driving the engine to rotate, and making the engine ignite and start. Therefore, when the generator battery is in a discharged state due to reasons such as the vehicle not being started for a long time or generator failure, the electric vehicle cannot be started; and when the vehicle cannot be started normally, the generator battery cannot be charged, and professional equipment or technicians are required to complete the replenishment of the generator battery power. Therefore, for ordinary vehicle users, the discharged generator battery is a very difficult problem. Therefore, how to timely and conveniently replenish the power of the discharged generator battery to ensure its normal working performance is an urgent problem to be solved. Summary of the Invention

[0003] The main purpose of this application is to provide an automotive power charging circuit and an automotive power system, aiming to solve the technical problem that it is relatively troublesome to replenish the power of the first vehicle battery in a discharged state.

[0004] To achieve the above invention purpose, this application provides an automotive power charging circuit for charging an automotive power supply. The automotive power supply includes a first battery and a second battery, and the second battery is used to provide a starting voltage for the vehicle. The circuit includes:

[0005] A first voltage detection module, a second voltage detection module, a DC-DC conversion module, a control module, a first dual-selection switch module, a second dual-selection switch module, a first terminal, a second terminal, and a third terminal;

[0006] The first dual-selection switch module includes a first relay, and the second dual-selection switch module includes a second relay. Both the first relay and the second relay include a set of dual-selection switches composed of a moving contact, a normally open static contact, and a normally closed static contact;

[0007] The control module is respectively connected to the first voltage detection module, the second voltage detection module, the DC-DC conversion module, the first relay, and the second relay;

[0008] The first voltage detection module is further configured to be connected to the first battery, measure the real-time voltage of the first battery and transmit it to the control module; the second voltage detection module is further configured to be connected to the second battery, measure the real-time voltage of the second battery and transmit it to the control module; the input end of the DC-DC conversion module is correspondingly connected to the first terminal and the third terminal, the output end of the DC-DC conversion module is correspondingly connected to the second terminal and the third terminal, and the third terminal is used for grounding;

[0009] The normally closed static contact of the first relay is used to be connected to the positive electrode of the first battery, the normally open static contact of the first relay is used to be connected to the positive electrode of the second battery, the moving contact of the first relay is connected to the second terminal, the control end of the first relay is connected to the first output end of the control module, the normally closed static contact of the second relay is used to be connected to the positive electrode of the second battery, the normally open static contact of the second relay is used to be connected to the positive electrode of the first battery, the moving contact of the second relay is connected to the first terminal, and the control end of the second relay is connected to the second output end of the control module;

[0010] The control module is configured to, when receiving a reverse charging instruction and the real-time voltages of the first battery and the second battery meet preset conditions, control the first relay and the second relay to be powered on and work, so that the first battery charges the second battery.

[0011] In some embodiments, the DC-DC conversion module includes a first switching tube, a second switching tube, a third switching tube, a fourth switching tube, a first freewheeling diode, a second freewheeling diode, a third freewheeling diode, a fourth freewheeling diode, a first capacitor, a second capacitor and a first inductor;

[0012] The first end of the first switching tube is respectively connected to the cathode of the first freewheeling diode, the first end of the first capacitor and the first terminal, the second end of the first switching tube is respectively connected to the anode of the first freewheeling diode, the first end of the second switching tube, the cathode of the second freewheeling diode and the first end of the first inductor, and the control end of the first switching tube is connected to the third output end of the control module;

[0013] The second end of the second switching tube is respectively connected to the second end of the fourth switching tube, the anode of the second freewheeling diode and the anode of the fourth freewheeling diode, the second end of the second switching tube is also used for grounding, and the control end of the second switching tube is connected to the fourth output end of the control module;

[0014] The first end of the third switching transistor is respectively connected to the cathode of the third freewheeling diode, the first end of the second capacitor, and the second terminal. The second end of the third switching transistor is respectively connected to the anode of the third freewheeling diode, the first end of the fourth switching transistor, the cathode of the fourth freewheeling diode, and the second end of the first inductor. The control end of the third switching transistor is connected to the fifth output terminal of the control module, and the control end of the fourth switching transistor is connected to the sixth output terminal of the control module.

[0015] In some embodiments, the vehicle power supply charging circuit further includes an anti-charge switch. The first end of the anti-charge switch is respectively connected to the anti-charge instruction receiving end of the control module and a second power supply, and the second end of the anti-charge switch is grounded. Wherein, when the anti-charge switch is closed, the anti-charge instruction receiving end of the control module receives a low-level signal, and when the anti-charge switch is open, the anti-charge instruction receiving end of the control module receives a high-level signal.

[0016] In some embodiments, the vehicle power supply charging circuit further includes an anti-charge indicator light. The first end of the anti-charge indicator light is connected to the seventh output terminal of the control module, and the second end of the anti-charge indicator light is grounded. The control module is further configured to control the anti-charge indicator light to be turned on when the anti-charge instruction receiving end receives a low-level signal, and to control the anti-charge indicator light to be turned off when the anti-charge instruction receiving end receives a high-level signal.

[0017] In some embodiments, the first voltage detection module includes a first resistor, a second resistor, a third resistor, a fourth resistor, and a third capacitor, and the second voltage detection module includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a fourth capacitor;

[0018] The first end of the first resistor is respectively connected to the normally-closed static contact of the first relay and the normally-open static contact of the second relay. The first end of the first resistor is further used to connect to the positive electrode of the first battery. The second end of the first resistor is connected to the first end of the second resistor. The second end of the second resistor is respectively connected to the first end of the third resistor and the first end of the fourth resistor. The second end of the fourth resistor is respectively connected to the first end of the third capacitor and the first voltage signal input terminal of the control module. The second end of the third resistor and the second end of the third capacitor are both grounded;

[0019] The first end of the fifth resistor is respectively connected to the normally open stationary contact of the first relay and the normally closed stationary contact of the second relay. The first end of the fifth resistor is also used to connect to the positive electrode of the second battery. The second end of the fifth resistor is connected to the first end of the sixth resistor. The second end of the sixth resistor is respectively connected to the first end of the seventh resistor and the first end of the eighth resistor. The second end of the eighth resistor is respectively connected to the first end of the fourth capacitor and the second voltage signal input end of the control module. The second end of the seventh resistor and the second end of the fourth capacitor are both grounded.

[0020] In some embodiments, the vehicle power charging circuit further includes a third dual - selection switch module. The third dual - selection switch module includes a third relay. The third relay includes a dual - selection switch composed of a normally open stationary contact, a normally closed stationary contact, and a moving contact.

[0021] The normally open stationary contact of the third relay is left floating. The normally closed stationary contact of the third relay is respectively connected to the first end of the first voltage detection module, the normally closed contact of the first relay, and is used to connect to the positive electrode of the first battery. The moving contact of the third relay is connected to the normally open stationary contact of the second relay. The control end of the third relay is connected to the eighth output end of the control module.

[0022] In some embodiments, the DC - DC conversion module further includes a current detection unit.

[0023] The first end of the current detection unit is respectively connected to the first end of the second capacitor, the first end of the third switch tube, and the cathode of the third free - wheeling diode. The second end of the current detection unit is connected to the second terminal. The output end of the current detection unit is connected to the current signal input end of the control module.

[0024] In some embodiments, the first dual - selection switch module further includes a fifth switch tube, a fifth free - wheeling diode, a ninth resistor, a tenth resistor, and an eleventh resistor. The second dual - selection switch module further includes a sixth switch tube, a sixth free - wheeling diode, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor. The third dual - selection switch module further includes a seventh switch tube, a seventh free - wheeling diode, a fifteenth resistor, a sixteenth resistor, and a seventeenth resistor.

[0025] The first end of the fifth switching tube is respectively connected to the first end of the coil of the first relay and the anode of the fifth freewheeling diode. The second end of the fifth switching tube is connected to the first end of the ninth resistor and grounded. The control end of the fifth switching tube is respectively connected to the second end of the ninth resistor and the first end of the tenth resistor. The second end of the tenth resistor is connected to the first output end of the control module. The first end of the eleventh resistor is respectively connected to the second end of the coil of the first relay and the cathode of the fifth freewheeling diode. The second end of the eleventh resistor is used to connect to the first power supply.

[0026] The first end of the sixth switching tube is respectively connected to the first end of the coil of the second relay and the anode of the sixth freewheeling diode. The second end of the sixth switching tube is connected to the first end of the twelfth resistor and grounded. The control end of the sixth switching tube is respectively connected to the second end of the twelfth resistor and the first end of the thirteenth resistor. The second end of the thirteenth resistor is connected to the second output end of the control module. The first end of the fourteenth resistor is respectively connected to the second end of the coil of the second relay and the cathode of the sixth freewheeling diode. The second end of the fourteenth resistor is used to connect to the first power supply.

[0027] The first end of the seventh switching tube is respectively connected to the first end of the coil of the third relay and the anode of the seventh freewheeling diode. The second end of the seventh switching tube is connected to the first end of the fifteenth resistor and grounded. The control end of the seventh switching tube is respectively connected to the second end of the fifteenth resistor and the first end of the sixteenth resistor. The second end of the sixteenth resistor is connected to the eighth output end of the control module. The first end of the seventeenth resistor is respectively connected to the second end of the coil of the third relay and the cathode of the seventh freewheeling diode. The second end of the seventeenth resistor is used to connect to the first power supply.

[0028] In some embodiments, the DC-DC conversion module further includes a first optocoupler, a second optocoupler, a third optocoupler, and a fourth optocoupler. The signal input end of the first optocoupler is connected to the third output end of the control module. The signal output end of the first optocoupler is connected to the control end of the first switching tube. The signal input end of the second optocoupler is connected to the fourth output end of the control module. The signal output end of the second optocoupler is connected to the control end of the second switching tube. The signal input end of the third optocoupler is connected to the fifth output end of the control module. The signal output end of the first optocoupler is connected to the control end of the third switching tube. The signal input end of the fourth optocoupler is connected to the sixth output end of the control module. The signal output end of the fourth optocoupler is connected to the control end of the fourth switching tube. The power supply ends of the first optocoupler, the second optocoupler, the third optocoupler, and the fourth optocoupler are all used to connect to the third power supply.

[0029] The present application also provides an automotive power supply system, which is characterized by including a first battery, a second battery, and the automotive power supply charging circuit provided in any of the above embodiments. The automotive power supply charging circuit is respectively connected to the first battery and the second battery, and is used to perform a charging operation on the first battery and the second battery.

[0030] The beneficial effect of the embodiment of the present application is: different from the prior art, the present application provides an automotive power supply charging circuit and an automotive power supply system, including: a first voltage detection module, a second voltage detection module, a DC-DC conversion module, a control module, a first dual-selection switch module, a second dual-selection switch module, a first terminal, a second terminal, and a third terminal; the first dual-selection switch module includes a first relay, the second dual-selection switch module includes a second relay, and both the first relay and the second relay include a group of dual-selection switches composed of a moving contact, a normally open static contact, and a normally closed static contact. When the control module receives a reverse charging instruction, and the real-time voltage of the first battery and the real-time voltage of the second battery detected by the first voltage detection module and the second voltage detection module meet the preset conditions, the control module controls the coils of the first relay and the second relay to be energized, so that the normally closed contact of the first relay is opened, the normally open contact is closed, and the normally closed contact of the second relay is opened, and the normally open contact is closed, that is, finally the first battery changes from being connected to the second terminal P2 to being connected to the first terminal, and the second battery changes from being connected to the first terminal to being connected to the second terminal. Then, the output voltage of the first battery is output to the input end of the second battery after passing through the DC-DC conversion module, thus realizing the operation of charging the second battery in a timely and convenient manner, and solving the problem that the charging of the second battery was relatively troublesome in the past. Description of the Drawings

[0031] Figure 1 is a schematic circuit diagram of the automotive power supply charging circuit provided in an embodiment of the present application;

[0032] Figure 2 is a schematic circuit diagram of the DC-DC conversion module in the automotive power supply charging circuit provided in an embodiment of the present application;

[0033] Figure 3 is a schematic circuit diagram of the automotive power supply charging circuit provided in another embodiment of the present application;

[0034] Figure 4 is a schematic circuit diagram of the automotive power supply charging circuit provided in another embodiment of the present application;

[0035] Figure 5 is a schematic circuit diagram of the automotive power supply charging circuit provided in another embodiment of the present application;

[0036] Figure 6Schematic diagram of the circuit structure of the vehicle power charging circuit provided by another embodiment of the present application;

[0037] Figure 7 Schematic diagram of the circuit structure of the DC-DC conversion module in the vehicle power charging circuit provided by another embodiment of the present application;

[0038] Figure 8 Schematic diagram of the circuit structure of the DC-DC conversion module in the vehicle power charging circuit provided by another embodiment of the present application;

[0039] Figure 9 Schematic diagram of the circuit structure of the DC-DC conversion module in the vehicle power charging circuit provided by another embodiment of the present application;

[0040] Figure 10 Schematic diagram of the circuit structure of the vehicle power charging circuit provided by another embodiment of the present application;

[0041] Figure 11 Schematic diagram of the structure of the vehicle power system provided by an embodiment of the present application. Detailed implementation manners

[0042] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all fall within the protection scope of the present invention.

[0043] To facilitate the understanding of the present application, the present application will be described in more detail below with reference to the accompanying drawings and specific embodiments. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not used to limit the present application.

[0044] It should be noted that if there is no conflict, the various features in the embodiments of the present application can be combined with each other, and all are within the protection scope of the present application. In addition, although the functional module division is carried out in the device schematic diagram, in some cases, it can be different from the module division in the device. In addition, the terms "first", "second", etc. used herein do not limit the data, execution order, etc., but only distinguish the same items or similar items with basically the same functions and effects.

[0045] The present application provides a vehicle power charging circuit for charging a vehicle power supply. The above vehicle power supply includes a first battery and a second battery. Among them, the second battery is used to provide a starting voltage for the vehicle. Please refer to Figure 1, the vehicle power charging circuit 100 includes: a first voltage detection module 10, a second voltage detection module 20, a DC-DC conversion module 30, a control module 40, a first dual-selection switch module 50, a second dual-selection switch module 60, a first terminal P1, a second terminal P2, and a third terminal P3.

[0046] Among them, the first dual-selection switch module 50 includes a first relay K1, and the second dual-selection switch module 60 includes a second relay K2. Both the first relay K1 and the second relay K2 include a set of dual-selection switches composed of a moving contact, a normally open static contact, and a normally closed static contact.

[0047] The control module 40 is respectively connected to the first voltage detection module 10, the second voltage detection module 20, the DC-DC conversion module 30, the first relay K1, and the second relay K2; the first voltage detection module is further used to be connected to the first battery, for measuring the real-time voltage of the first battery and transmitting it to the control module 40; the second voltage detection module 20 is further used to be connected to the second battery, for measuring the real-time voltage of the second battery and transmitting it to the control module 40; the input end of the DC-DC conversion module 30 is correspondingly connected to the first terminal P1 and the third terminal P3, the output end of the DC-DC conversion module 40 is correspondingly connected to the second terminal P2 and the third terminal P3, and the third terminal P3 is used for grounding.

[0048] The normally closed static contact of the first relay K1 is used to be connected to the positive electrode of the first battery, the normally open static contact of the first relay K1 is used to be connected to the positive electrode of the second battery, the moving contact of the first relay K1 is connected to the second terminal P2, the control end of the first relay K1 is connected to the first output end of the control module 40, the normally closed static contact of the second relay K2 is used to be connected to the positive electrode of the second battery, the normally open static contact of the second relay K2 is used to be connected to the positive electrode of the first battery, the moving contact of the second relay K2 is connected to the first terminal P1, and the control end of the second relay K2 is connected to the second output end of the control module 40.

[0049] The control module 40 is used to control the first relay K1 and the second relay K2 to be energized and work when receiving a reverse charging instruction and the real-time voltages of the first battery and the second battery received meet the preset conditions, so that the first battery charges the second battery.

[0050] The working principle of the vehicle power charging circuit 100 is as follows:

[0051] During the normal operation of the vehicle, alternating current voltage is generated by the on-board generator, and stable direct current voltage is obtained through a preset AC-DC conversion module and voltage regulator, etc., to charge the first battery and the second battery and supply power to in-vehicle electrical devices. The starting process of the vehicle requires the second battery to provide a starting voltage to complete the ignition start of the vehicle. At this time, the remaining power in the second battery needs to meet a preset threshold to provide sufficient starting voltage. If the second battery is discharged due to reasons such as the vehicle not being started for a long time or generator failure, the second battery needs to be replenished with power to complete the ignition start of the vehicle.

[0052] The control module 40 in the vehicle power charging circuit 100 receives the real-time voltage signal of the first battery collected in real time by the first voltage detection module 10 and the real-time voltage signal of the second battery collected in real time by the second voltage detection module 20, and also detects in real time whether there is a reverse charging instruction input (that is, whether the user needs the first battery to supply power to the second battery to replenish the power of the second battery). When receiving the reverse charging instruction, first, it is determined whether the real-time voltage of the first battery and the real-time voltage of the second battery meet the preset conditions (for example, the real-time voltage of the first battery is greater than 12V and the voltage of the second battery is lower than 5V). If the preset conditions are met, the control module 40 outputs a first control signal CON_1 at its first output terminal and a second control signal CON_2 at its second output terminal. Exemplarily, in this embodiment, a low-level signal is output, so that the coils of the first relay K1 and the second relay K2 are energized, thereby opening the normally closed contacts and closing the normally open contacts of the first relay K1, and opening the normally closed contacts and closing the normally open contacts of the second relay K2. That is, the first battery changes from being connected to the second terminal P2 to being connected to the first terminal P1, and the second battery changes from being connected to the first terminal P1 to being connected to the second terminal P2. That is, the output voltage of the first battery is output to the input terminal of the second battery after passing through the DC-DC conversion module 30, thereby realizing the operation of charging the second battery.

[0053] It should be noted that the above description of "reverse charging" is relative to the process of the generator charging the first battery (in the embodiment of the present application, the first battery charges the second battery), rather than implying that the first battery and the second battery have a function of mutual charging.

[0054] In addition, it should be noted that the DC-DC conversion module 30 in this embodiment can be a step-down DC conversion method or a step-up DC conversion method. In this embodiment, an existing DC-DC conversion module is selected to implement the function of DC conversion. The circuit composition and working principle of the DC-DC conversion module can refer to the prior art and will not be elaborated here.

[0055] An automotive power supply charging circuit 100 provided by the present application is used to charge an automotive power supply. The automotive power supply includes a first battery and a second battery, and the second battery is used to provide a starting voltage for the vehicle. The automotive power supply charging circuit 100 includes a first voltage detection module 10, a second voltage detection module 20, a DC-DC conversion module 30, a control module 40, a first dual-selection switch module 50, a second dual-selection switch module 60, a first terminal P1, a second terminal P2, and a third terminal P3; the first dual-selection switch module 50 includes a first relay K1, the second dual-selection switch module 60 includes a second relay K2, and both the first relay K2 and the second relay K2 include a set of dual-selection switches composed of a moving contact, a normally open static contact, and a normally closed static contact. When the control module 40 receives a reverse charging instruction and the real-time voltages of the first battery and the second battery detected by the first voltage detection module 10 and the second voltage detection module 20 meet preset conditions, the control module 40 is caused to control the coils of the first relay K1 and the second relay K2 to be energized, so that the normally closed contact of the first relay K1 is opened, the normally open contact is closed, and the normally closed contact of the second relay K2 is opened, the normally open contact is closed, that is, finally, the first battery changes from being connected to the second terminal P2 to being connected to the first terminal P1, and the second battery changes from being connected to the first terminal P1 to being connected to the second terminal P2. Then, the output voltage of the first battery is output to the input end of the second battery after passing through the DC-DC conversion module 30, thereby realizing the operation of charging the second battery in a timely and convenient manner, and solving the problem that it was more troublesome to charge the second battery in the past.

[0056] In some embodiments, please refer to Figure 2 , the DC-DC conversion module 30 includes a first switching tube Q1, a second switching tube Q2, a third switching tube Q3, a fourth switching tube Q4, a first freewheeling diode D1, a second freewheeling diode D2, a third freewheeling diode D3, a fourth freewheeling diode D4, a first capacitor C1, a second capacitor C2, and a first inductor L1.

[0057] The first end of the first switching tube Q1 is respectively connected to the cathode of the first freewheeling diode D1, the first end of the first capacitor C1, and the first terminal P1. The second end of the first switching tube Q1 is respectively connected to the anode of the first freewheeling diode D1, the first end of the second switching tube Q2, the cathode of the second freewheeling diode D2, and the first end of the first inductor L1. The control end of the first switching tube Q1 is connected to the third output end of the control module 40.

[0058] The second end of the second switching tube Q2 is respectively connected to the second end of the fourth switching tube Q4, the anode of the second freewheeling diode D2, and the anode of the fourth freewheeling diode D4. The second end of the second switching tube Q2 is also used for grounding. The control end of the second switching tube Q2 is connected to the fourth output end of the control module 40.

[0059] The first end of the third switching transistor Q3 is respectively connected to the cathode of the third freewheeling diode D3, the first end of the second capacitor C2, and the second terminal P2. The second end of the third switching transistor Q3 is respectively connected to the anode of the third freewheeling diode D3, the first end of the fourth switching transistor Q4, the cathode of the fourth freewheeling diode D4, and the second end of the first inductor L1. The control end of the third switching transistor Q3 is connected to the fifth output end of the control module 40, and the control end of the fourth switching transistor Q4 is connected to the sixth output end of the control module 40.

[0060] The working principle of the DC-DC conversion module 30 is as follows:

[0061] The DC-DC conversion module 30 in this embodiment has both boost and buck DC conversion modes. When the DC-DC conversion module 30 operates in the buck mode, then:

[0062] The second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 always remain in the cut-off state. The first switching transistor Q1 conducts or cuts off according to the control signal CON_3 (such as a PWM signal) received at the third output end of the control module 40. When the first switching transistor Q1 conducts, the energy of the first capacitor C1 is transmitted to the second capacitor C2 via the first switching transistor Q1, the first inductor L1, and the third freewheeling diode D3. When the first switching transistor Q1 cuts off, freewheeling is carried out through the freewheeling loop formed by the first inductor L1, the third freewheeling diode D3, the second capacitor C2, the second freewheeling diode D2, and the fourth freewheeling diode D4, thereby completing the buck conversion of the DC voltage.

[0063] When the DC-DC conversion module 30 operates in the boost mode, then:

[0064] The first switching transistor Q1 always remains in the conducting state, the second switching transistor Q2 and the third switching transistor Q3 always remain in the cut-off state. The fourth switching transistor Q4 conducts or cuts off according to the control signal CON_6 (such as a PWM signal) received at the sixth output end of the control module 40. When the fourth switching transistor Q4 conducts, part of the energy of the first capacitor C1 is stored in the first inductor L1 via the first switching transistor Q1, the first inductor L1, and the fourth switching transistor Q4. When the fourth switching transistor Q4 cuts off, the energy of the first capacitor C1 is superimposed on the energy stored in the first inductor L1 and transmitted to the second capacitor C2 together through the loop formed by the first inductor L1, the third freewheeling diode D3, and the second capacitor C2, thereby completing the boost conversion of the DC voltage.

[0065] In some embodiments, please refer to Figure 3, the vehicle power charging circuit further includes a reverse charging switch S1. The first end of the reverse charging switch S1 is respectively connected to the reverse charging instruction receiving end of the control module 40 and the second power supply VCC2, and the second end of the reverse charging switch S1 is grounded. Wherein, when the reverse charging switch S1 is closed, the reverse charging instruction receiving end of the control module 40 receives a low-level signal, and when the reverse charging switch S1 is open, the reverse charging instruction receiving end of the control module 40 receives a high-level signal. That is, in this embodiment, when the user needs to charge the second battery with the first battery, the reverse charging switch S1 is controlled to close (for example, by means of a button, a knob, etc.), so that the reverse charging instruction receiving end of the control module 40 receives a low-level signal (i.e., the reverse charging instruction), thereby controlling the first relay K1 and the second relay K2 to be energized and performing the operation of charging the second battery with the first battery.

[0066] In some embodiments, please refer back to Figure 3 , the vehicle power charging circuit further includes a reverse charging indicator LED1. The first end of the reverse charging indicator LED1 is connected to the seventh output end of the control module 40, and the second end of the reverse charging indicator LED1 is grounded. The control module 40 is further configured to control the reverse charging indicator to light up when its reverse charging instruction receiving end receives a low-level signal, and to control the reverse charging indicator to turn off when its reverse charging instruction receiving end receives a high-level signal. In this embodiment, the reverse charging indicator is an LED lamp. The anode of the LED lamp is connected to the first output end of the control module 40, and the cathode of the LED lamp is grounded. When the reverse charging instruction receiving end of the control module 40 receives a low-level signal (i.e., the reverse charging switch is closed), a high-level signal is output at its seventh output end to light up the LED lamp; when the reverse charging instruction receiving end of the control module 40 receives a high-level signal (i.e., the reverse charging switch is open), a low-level signal is output at its seventh output end to turn off the LED lamp.

[0067] In some embodiments, please refer to Figure 4 , the first voltage detection module 10 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a third capacitor C3, and the second voltage detection module 20 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a fourth capacitor C4.

[0068] The first end of the first resistor R1 is respectively connected to the normally closed stationary contact of the first relay K1 and the normally open stationary contact of the second relay K2. The first end of the first resistor R1 is also used to connect to the positive electrode of the first battery. The second end of the first resistor R1 is connected to the first end of the second resistor R2. The second end of the second resistor R2 is respectively connected to the first end of the third resistor R3 and the first end of the fourth resistor R4. The second end of the fourth resistor R4 is respectively connected to the first end of the third capacitor C3 and the first voltage signal input end of the control module 40. The second ends of the third resistor R3 and the third capacitor C3 are both grounded.

[0069] The first end of the fifth resistor R5 is respectively connected to the normally open stationary contact of the first relay K1 and the normally closed stationary contact of the second relay K2. The first end of the fifth resistor R5 is also used to connect to the positive electrode of the second battery. The second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6. The second end of the sixth resistor R6 is respectively connected to the first end of the seventh resistor R7 and the first end of the eighth resistor R8. The second end of the eighth resistor R8 is respectively connected to the first end of the fourth capacitor C1 and the second voltage signal input end of the control module 40. The second ends of the seventh resistor R7 and the fourth capacitor C2 are both grounded.

[0070] In this embodiment, the first resistor R1, the second resistor R2, and the third resistor R3 form a first voltage dividing unit. After dividing the real-time voltage of the first battery, it is transmitted to the first voltage signal input end of the control module 40 through the first decoupling unit composed of the fourth resistor R4 and the third capacitor C3. The fifth resistor R5, the sixth resistor R6, and the seventh resistor R7 form a second voltage dividing unit. After dividing the real-time voltage of the second battery, it is transmitted to the second voltage signal input end of the control module 40 through the second decoupling unit composed of the eighth resistor R8 and the fourth capacitor C4, thereby completing the voltage acquisition of the first battery and the second battery.

[0071] In some embodiments, please refer to Figure 5 , the vehicle power charging circuit 100 further includes: a third dual-selection switch module 70. The third dual-selection switch module 70 includes a third relay K3. The third relay K3 includes a dual-selection switch composed of a normally open stationary contact, a normally closed stationary contact, and a moving contact. The normally open stationary contact of the third relay K3 is suspended. The normally closed stationary contact of the third relay K3 is respectively connected to the first end of the first voltage detection module 10, the normally closed contact of the first relay K1, and is used to connect to the positive electrode of the first battery. The moving contact of the third relay K3 is connected to the normally open stationary contact of the second relay K2. The control end of the third relay K3 is connected to the eighth output end of the control module 40.

[0072] In this embodiment, when it is necessary to suspend the charging of the first battery to the second battery, the control module 40 outputs a low-level signal at its eighth output end, so that the coil of the third relay K3 is energized, thereby closing its normally open contact and opening its normally closed contact, thereby disconnecting the path between the first battery and the first terminal P1 and suspending the charging of the second battery.

[0073] In some embodiments, please refer to Figure 6, the first dual - selection switch module 50 further includes a fifth switching transistor Q5, a fifth free - wheeling diode D5, a ninth resistor R9, a tenth resistor R10, and an eleventh resistor R11. The second dual - selection switch module 60 further includes a sixth switching transistor Q6, a sixth free - wheeling diode D6, a twelfth resistor R12, a thirteenth resistor R13, and a fourteenth resistor R14. The third dual - selection switch module 70 further includes a seventh switching transistor Q7, a seventh free - wheeling diode D7, a fifteenth resistor R15, a sixteenth resistor R16, and a seventeenth resistor R17.

[0074] The first end of the fifth switching transistor Q5 is respectively connected to the first end of the coil of the first relay K1 and the anode of the fifth free - wheeling diode D5. The second end of the fifth switching transistor Q5 is connected to the first end of the ninth resistor R9 and grounded. The control end of the fifth switching transistor Q5 is respectively connected to the second end of the ninth resistor R9 and the first end of the tenth resistor R10. The second end of the tenth resistor R10 is connected to the first output end of the control module 40. The first end of the eleventh resistor R11 is respectively connected to the second end of the coil of the first relay K1 and the cathode of the fifth free - wheeling diode D5. The second end of the eleventh resistor R11 is used to connect to the first power supply VCC1.

[0075] The first end of the sixth switching transistor Q6 is respectively connected to the first end of the coil of the second relay K2 and the anode of the sixth free - wheeling diode D6. The second end of the sixth switching transistor Q6 is connected to the first end of the twelfth resistor R12 and grounded. The control end of the sixth switching transistor Q6 is respectively connected to the second end of the twelfth resistor R12 and the first end of the thirteenth resistor R13. The second end of the thirteenth resistor R13 is connected to the second output end of the control module. The first end of the fourteenth resistor R14 is respectively connected to the second end of the coil of the second relay K2 and the cathode of the sixth free - wheeling diode. The second end of the fourteenth resistor R14 is used to connect to the first power supply VCC1.

[0076] The first end of the seventh switching transistor Q7 is respectively connected to the first end of the coil of the third relay K3 and the anode of the seventh free - wheeling diode D7. The second end of the seventh switching transistor Q7 is connected to the first end of the fifteenth resistor R15 and grounded. The control end of the seventh switching transistor Q7 is respectively connected to the second end of the fifteenth resistor R15 and the first end of the sixteenth resistor R16. The second end of the sixteenth resistor R16 is connected to the eighth output end of the control module. The first end of the seventeenth resistor R17 is respectively connected to the second end of the coil of the third relay K3 and the cathode of the seventh free - wheeling diode D7. The second end of the seventeenth resistor R17 is used to connect to the first power supply VCC1.

[0077] In this embodiment, the ninth resistor R9, the twelfth resistor R12, and the fifteenth resistor R15 are respectively the reliable cut-off resistors of the fifth switching transistor Q5, the sixth switching transistor Q6, and the seventh switching transistor Q7, which are used to ensure the reliable cut-off of the switching transistors; the tenth resistor R10, the thirteenth resistor R13, and the sixteenth resistor R16 are respectively the current-limiting resistors of the fifth switching transistor Q5, the sixth switching transistor Q6, and the seventh switching transistor Q7, which are used to prevent the switching transistors from being burned out due to overcurrent; the eleventh resistor R11, the fourteenth resistor R14, and the seventeenth resistor R17 are voltage-dividing resistors, which are used to adjust the voltage across the relay coil; the fifth freewheeling diode D5, the sixth freewheeling diode D6, and the seventh freewheeling diode D7 respectively provide freewheeling paths for the coils of the first relay K1, the second relay K2, and the third relay K3.

[0078] In some embodiments, please refer to Figure 7 , the DC-DC conversion module 30 further includes a first optocoupler U1, a second optocoupler U2, a third optocoupler U3, and a fourth optocoupler U4.

[0079] The signal input terminal of the first optocoupler U1 is connected to the third output terminal of the control module 40, the signal output terminal of the first optocoupler U1 is connected to the control terminal of the first switching transistor Q1, the signal input terminal of the second optocoupler U2 is connected to the fourth output terminal of the control module 40, the signal output terminal of the second optocoupler U2 is connected to the control terminal of the second switching transistor Q2, the signal input terminal of the third optocoupler U3 is connected to the fifth output terminal of the control module 40, the signal output terminal of the first optocoupler U1 is connected to the control terminal of the third switching transistor Q3, the signal input terminal of the fourth optocoupler U4 is connected to the sixth output terminal of the control module 40, the signal output terminal of the fourth optocoupler U4 is connected to the control terminal of the fourth switching transistor Q4, and the power supply terminals of the first optocoupler U1, the second optocoupler U2, the third optocoupler U3, and the fourth optocoupler U4 are all connected to the third power supply VCC3. The first optocoupler U1, the second optocoupler U2, the third optocoupler U3, and the fourth optocoupler U4 are used for optoelectronic isolation to reduce the interference received by the control module 40.

[0080] In some embodiments, please refer to Figure 8 , the DC-DC conversion module 30 further includes an eighth switching transistor Q8, a ninth switching transistor Q9, a tenth switching transistor Q10, and an eleventh switching transistor Q11. Among them, the eighth switching transistor Q8, the ninth switching transistor Q9, the tenth switching transistor Q10, and the eleventh switching transistor Q11 are respectively connected between the input terminals of the first optocoupler U1, the second optocoupler U2, the third optocoupler U3, and the fourth optocoupler U4, and are used to quickly cut off (or pause) the input of the control signal of the optocoupler signal terminal.

[0081] In some embodiments, please refer to again Figure 8, the DC-DC conversion module 30 further includes a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, and an eighth capacitor C8. Among them, the fifth capacitor C5, the sixth capacitor C6, the seventh capacitor C7, and the eighth capacitor C8 are respectively connected between the power supply terminals of the first optocoupler U1, the second optocoupler U2, the third optocoupler U3, and the fourth optocoupler U4 and the ground, and are used to filter the voltage provided by the third power supply VCC3.

[0082] In some embodiments, please refer to again Figure 8 , the DC-DC conversion module 30 further includes an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-seventh resistor R27, a twenty-eighth resistor R28, a twenty-ninth resistor R29, an eighth diode D8, a ninth diode D9, a twelfth diode D10, and an eleventh diode D11. Among them, the eighteenth resistor R18, the twenty-first resistor R21, the twenty-fourth resistor R24, and the twenty-seventh resistor R27 are respectively the reliable cut-off resistors of the first switching tube, the second switching tube, the third switching tube, and the fourth switching tube. The nineteenth resistor R19, the twenty-second resistor R22, the twenty-fifth resistor R25, and the twenty-eighth resistor R28 are respectively the current-limiting resistors of the first switching tube, the second switching tube, the third switching tube, and the fourth switching tube. The twentieth resistor R20 and the eighth diode D8 form a first absorption unit for absorbing the spike voltage when the first switching tube is cut off. The twenty-third resistor R23 and the ninth diode D9 form a second absorption unit for absorbing the spike voltage when the second switching tube is cut off. The twenty-sixth resistor R26 and the twelfth diode D10 form a third absorption unit for absorbing the spike voltage when the third switching tube is cut off. The twenty-ninth resistor R29 and the eleventh diode D11 form a fourth absorption unit for absorbing the spike voltage when the fourth switching tube is cut off.

[0083] In some embodiments, please refer to Figure 9 , the DC-DC conversion module 30 further includes a current detection unit 301. The first end of the current detection unit 301 is respectively connected to the first end of the second capacitor C2, the first end of the third switching tube Q3, and the cathode of the third freewheeling diode D3. The second end of the current detection unit 301 is connected to the second terminal P2. The output end of the current detection unit 301 is connected to the current signal input end of the control module 40. The current detection unit 301 is used to detect the charging current of the second battery when the first battery charges the second battery. When the charging current is too large, the connection between the first battery and the second battery is disconnected to avoid overcurrent. In this embodiment, the current detection unit 301 is composed of a Hall sensor U5, a thirtieth resistor R30, a ninth capacitor C9, a tenth capacitor C10, and an eleventh capacitor C11.

[0084] In some embodiments, please refer to Figure 10 , the vehicle power charging circuit 100 further includes a first fuse FU1 and a second fuse FU2. The first fuse FU1 and the second fuse FU2 are used for overcurrent protection. When the current is too large, the fuses in the first fuse FU1 and the second fuse FU2 will melt, thereby disconnecting the current loop.

[0085] Please refer to Figure 11 , the present application further provides a vehicle power supply system 1000, including a first battery 200, a second battery 300, and the vehicle power charging circuit 100 provided in any of the above embodiments. The vehicle power charging circuit 100 is respectively connected to the first battery 200 and the second battery 300, and is used to perform a charging operation on the first battery 200 and the second battery 300.

[0086] A vehicle power charging circuit and a vehicle power supply system provided by the present application include a first voltage detection module, a second voltage detection module, a DC-DC conversion module, a control module, a first dual-selection switch module, a second dual-selection switch module, a first terminal, a second terminal, and a third terminal; the first dual-selection switch module includes a first relay, the second dual-selection switch module includes a second relay, and both the first relay and the second relay include a set of dual-selection switches composed of a moving contact, a normally open static contact, and a normally closed static contact. When the control module receives a reverse charging instruction and the real-time voltages of the first battery and the second battery detected by the first voltage detection module and the second voltage detection module meet preset conditions, the control module controls the coils of the first relay and the second relay to be energized, so that the normally closed contact of the first relay opens, the normally open contact closes, and the normally closed contact of the second relay opens, the normally open contact closes, that is, finally the first battery changes from being connected to the second terminal P2 to being connected to the first terminal, and the second battery changes from being connected to the first terminal to being connected to the second terminal. Then, the output voltage of the first battery passes through the DC-DC conversion module and is output to the input end of the second battery, thereby realizing the operation of charging the second battery in a timely and convenient manner, and solving the problem that the charging of the second battery was relatively troublesome in the past.

[0087] It should be noted that the above-described embodiments are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; under the idea of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above. For the sake of brevity, they are not provided in detail; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automotive power supply charging circuit for charging an automotive power supply, the automotive power supply including a first battery and a second battery, the second battery being used to provide a starting voltage for the vehicle, characterized in that, Including: A first voltage detection module, a second voltage detection module, a DC-DC conversion module, a control module, a first dual-selection switch module, a second dual-selection switch module, a first terminal, a second terminal, and a third terminal; the first dual-selection switch module includes a first relay, the second dual-selection switch module includes a second relay, and both the first relay and the second relay include a dual-selection switch composed of a moving contact, a normally open static contact, and a normally closed static contact; the control module is respectively connected to the first voltage detection module, the second voltage detection module, the DC-DC conversion module, the first relay, and the second relay. The first voltage detection module is further configured to be connected to the first battery, measure the real-time voltage of the first battery, and transmit it to the control module; the second voltage detection module is further configured to be connected to the second battery, measure the real-time voltage of the second battery, and transmit it to the control module; the input end of the DC-DC conversion module is correspondingly connected to the first terminal and the third terminal, the output end of the DC-DC conversion module is correspondingly connected to the second terminal and the third terminal, and the third terminal is used for grounding. The normally closed static contact of the first relay is used to be connected to the positive electrode of the first battery, the normally open static contact of the first relay is used to be connected to the positive electrode of the second battery, the moving contact of the first relay is connected to the second terminal, the control end of the first relay is connected to the first output end of the control module, the normally closed static contact of the second relay is used to be connected to the positive electrode of the second battery, the normally open static contact of the second relay is used to be connected to the positive electrode of the first battery, the moving contact of the second relay is connected to the first terminal, and the control end of the second relay is connected to the second output end of the control module. The control module is configured to, when receiving a reverse charging instruction and the real-time voltages of the first battery and the second battery meet a preset condition, control the first relay and the second relay to be powered on and work, so that the first battery charges the second battery.

2. The automotive power supply charging circuit according to claim 1, wherein, The DC-DC conversion module includes a first switching tube, a second switching tube, a third switching tube, a fourth switching tube, a first freewheeling diode, a second freewheeling diode, a third freewheeling diode, a fourth freewheeling diode, a first capacitor, a second capacitor, and a first inductor. The first end of the first switching tube is respectively connected to the cathode of the first freewheeling diode, the first end of the first capacitor, and the first terminal, the second end of the first switching tube is respectively connected to the anode of the first freewheeling diode, the first end of the second switching tube, the cathode of the second freewheeling diode, and the first end of the first inductor, and the control end of the first switching tube is connected to the third output end of the control module. The second end of the second switching tube is respectively connected to the second end of the fourth switching tube, the anode of the second freewheeling diode, and the anode of the fourth freewheeling diode, the second end of the second switching tube is further used for grounding, and the control end of the second switching tube is connected to the fourth output end of the control module. The first end of the third switching transistor is respectively connected to the cathode of the third freewheeling diode, the first end of the second capacitor, and the second terminal. The second end of the third switching transistor is respectively connected to the anode of the third freewheeling diode, the first end of the fourth switching transistor, the cathode of the fourth freewheeling diode, and the second end of the first inductor. The control end of the third switching transistor is connected to the fifth output terminal of the control module, and the control end of the fourth switching transistor is connected to the sixth output terminal of the control module.

3. The automotive power supply charging circuit according to claim 1, characterized in that, It further includes: A reverse charge switch; The first end of the reverse charge switch is respectively connected to the reverse charge instruction receiving end of the control module and the second power supply, and the second end of the reverse charge switch is grounded. Wherein, when the reverse charge switch is closed, the reverse charge instruction receiving end of the control module receives a low-level signal, and when the reverse charge switch is open, the reverse charge instruction receiving end of the control module receives a high-level signal.

4. The automotive power supply charging circuit according to claim 3, wherein It further includes: A reverse charge indicator light; The first end of the reverse charge indicator light is connected to the seventh output terminal of the control module, and the second end of the reverse charge indicator light is grounded. The control module is further configured to control the reverse charge indicator light to be turned on when the reverse charge instruction receiving end receives a low-level signal, and to control the reverse charge indicator light to be turned off when the reverse charge instruction receiving end receives a high-level signal.

5. The automotive power supply charging circuit according to claim 1, characterized in that, The first voltage detection module includes a first resistor, a second resistor, a third resistor, a fourth resistor, and a third capacitor, and the second voltage detection module includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a fourth capacitor; The first end of the first resistor is respectively connected to the normally closed stationary contact of the first relay and the normally open stationary contact of the second relay. The first end of the first resistor is also used to connect to the positive electrode of the first battery. The second end of the first resistor is connected to the first end of the second resistor. The second end of the second resistor is respectively connected to the first end of the third resistor and the first end of the fourth resistor. The second end of the fourth resistor is respectively connected to the first end of the third capacitor and the first voltage signal input terminal of the control module. The second end of the third resistor and the second end of the third capacitor are both grounded; The first end of the fifth resistor is respectively connected to the normally open stationary contact of the first relay and the normally closed stationary contact of the second relay. The first end of the fifth resistor is also used to connect to the positive electrode of the second battery. The second end of the fifth resistor is connected to the first end of the sixth resistor. The second end of the sixth resistor is respectively connected to the first end of the seventh resistor and the first end of the eighth resistor. The second end of the eighth resistor is respectively connected to the first end of the fourth capacitor and the second voltage signal input terminal of the control module. The second end of the seventh resistor and the second end of the fourth capacitor are both grounded.

6. The automotive power supply charging circuit according to claim 1, wherein It further includes: A third dual-selection switch module; The third dual-selection switch module includes a third relay, and the third relay includes a set of dual-selection switches composed of a normally open stationary contact, a normally closed stationary contact, and a moving contact; The normally open static contact of the third relay is floating. The normally closed static contacts of the third relay are respectively connected to the first end of the first voltage detection module, the normally closed contact of the first relay, and the positive electrode of the first battery for connection. The moving contact of the third relay is connected to the normally open static contact of the second relay, and the control end of the third relay is connected to the eighth output end of the control module.

7. The automotive power supply charging circuit according to claim 2, characterized in that, The DC-DC conversion module further includes a current detection unit; The first end of the current detection unit is respectively connected to the first end of the second capacitor, the first end of the third switching tube, and the cathode of the third freewheeling diode. The second end of the current detection unit is connected to the second terminal, and the output end of the current detection unit is connected to the current signal input end of the control module.

8. The automotive power supply charging circuit according to claim 6, wherein, The first dual-selection switch module further includes a fifth switching tube, a fifth freewheeling diode, a ninth resistor, a tenth resistor, and an eleventh resistor. The second dual-selection switch module further includes a sixth switching tube, a sixth freewheeling diode, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor. The third dual-selection switch module further includes a seventh switching tube, a seventh freewheeling diode, a fifteenth resistor, a sixteenth resistor, and a seventeenth resistor; The first end of the fifth switching tube is respectively connected to the first end of the coil of the first relay and the anode of the fifth freewheeling diode. The second end of the fifth switching tube is connected to the first end of the ninth resistor and grounded. The control end of the fifth switching tube is respectively connected to the second end of the ninth resistor and the first end of the tenth resistor. The second end of the tenth resistor is connected to the first output end of the control module. The first end of the eleventh resistor is respectively connected to the second end of the coil of the first relay and the cathode of the fifth freewheeling diode, and the second end of the eleventh resistor is used to connect to the first power supply; The first end of the sixth switching tube is respectively connected to the first end of the coil of the second relay and the anode of the sixth freewheeling diode. The second end of the sixth switching tube is connected to the first end of the twelfth resistor and grounded. The control end of the sixth switching tube is respectively connected to the second end of the twelfth resistor and the first end of the thirteenth resistor. The second end of the thirteenth resistor is connected to the second output end of the control module. The first end of the fourteenth resistor is respectively connected to the second end of the coil of the second relay and the cathode of the sixth freewheeling diode, and the second end of the fourteenth resistor is used to connect to the first power supply; The first end of the seventh switching tube is respectively connected to the first end of the coil of the third relay and the anode of the seventh freewheeling diode. The second end of the seventh switching tube is connected to the first end of the fifteenth resistor and grounded. The control end of the seventh switching tube is respectively connected to the second end of the fifteenth resistor and the first end of the sixteenth resistor. The second end of the sixteenth resistor is connected to the eighth output end of the control module. The first end of the seventeenth resistor is respectively connected to the second end of the coil of the third relay and the cathode of the seventh freewheeling diode, and the second end of the seventeenth resistor is used to connect to the first power supply.

9. The automotive power supply charging circuit according to claim 2, wherein The DC-DC conversion module further includes a first optocoupler, a second optocoupler, a third optocoupler, and a fourth optocoupler; The signal input end of the first optocoupler is connected to the third output end of the control module, the signal output end of the first optocoupler is connected to the control end of the first switching tube, the signal input end of the second optocoupler is connected to the fourth output end of the control module, the signal output end of the second optocoupler is connected to the control end of the second switching tube, the signal input end of the third optocoupler is connected to the fifth output end of the control module, the signal output end of the first optocoupler is connected to the control end of the third switching tube, the signal input end of the fourth optocoupler is connected to the sixth output end of the control module, and the signal output end of the fourth optocoupler is connected to the control end of the fourth switching tube; the power supply ends of the first optocoupler, the second optocoupler, the third optocoupler, and the fourth optocoupler are all used to connect to a third power supply.

10. An automotive power supply system, characterized in that, It includes a first battery, a second battery, and the vehicle power charging circuit according to any one of claims 1-9; The vehicle power charging circuit is respectively connected to the first battery and the second battery and is used to perform a charging operation on the first battery and the second battery.

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