A vehicle-mounted power supply circuit, a vehicle-mounted terminal and a vehicle

Abstract

This application provides an on-board power supply circuit, an on-board terminal, and a vehicle, relating to the technical field of electronic circuits. The on-board power supply circuit includes: a first voltage conversion circuit and an ignition switch circuit. The first voltage conversion circuit converts the voltage output by the power supply into a target voltage, which is used to power the load. A first input terminal of the ignition switch circuit receives an ignition switch signal output by the ignition switch. The output terminal of the ignition switch is connected to the enable terminal of the first voltage conversion circuit. The ignition switch circuit controls the conduction state of the first voltage conversion circuit according to the ignition switch signal. Specifically, when the ignition switch signal indicates that the ignition switch is off, the ignition switch circuit controls the first voltage conversion circuit to disconnect. This addresses the problem in existing vehicles where the power supply circuit continues to operate even when the ignition switch is off, leading to continuous consumption of the energy stored in the vehicle battery and potentially causing battery damage.

Description

Technical Field

[0001] This application relates to the technical field of electronic circuits, and more specifically, to an on-board power supply circuit, an on-board terminal, and a vehicle. Background Technology

[0002] Vehicle-mounted terminals are widely used in passenger vehicles, logistics vehicles, construction machinery and other fields. Vehicle managers can communicate with vehicle monitoring software through the vehicle-mounted terminal to keep track of vehicle operation information in real time, which greatly facilitates vehicle management, improves management efficiency and automation level, and further ensures the driving safety of drivers and passengers.

[0003] Currently, the power supply circuit of an in-vehicle terminal generally includes: a voltage conversion circuit and a control circuit.

[0004] However, the power supply circuit continues to operate even when the vehicle's ignition switch is turned off, causing the energy stored in the vehicle battery to be continuously consumed, which can easily lead to damage to the vehicle battery. Summary of the Invention

[0005] This application provides an on-board power supply circuit, an on-board terminal, and a vehicle to solve the problem that in existing vehicles, the power supply circuit continues to work even when the ignition switch is turned off, causing the energy stored in the on-board battery to be continuously consumed and easily leading to damage to the on-board battery.

[0006] In a first aspect, this application provides an on-board power supply circuit, comprising: a first voltage conversion circuit and an ignition switch circuit, wherein the first voltage conversion circuit is used to convert the voltage output by the power supply into a target voltage, the target voltage being used to supply power to a load; a first input terminal of the ignition switch circuit is used to receive an ignition switch signal output by the ignition switch, the output terminal of the ignition switch is connected to the enable terminal of the first voltage conversion circuit, and the ignition switch circuit is used to control the conduction state of the first voltage conversion circuit according to the ignition switch signal, wherein when the ignition switch signal indicates that the ignition switch is off, the ignition switch circuit controls the first voltage conversion circuit to be off.

[0007] In this embodiment, the ignition switch circuit controls the conduction state of the first voltage conversion circuit according to the ignition switch signal. Thus, when the ignition switch signal indicates that the ignition switch is off, the ignition switch circuit controls the first voltage conversion circuit to turn off, so that the power supply circuit no longer works when the ignition switch is off, preventing the energy stored in the vehicle battery from being continuously consumed after the ignition switch is off, thereby preventing damage to the vehicle battery.

[0008] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the ignition switch circuit further includes a second input terminal. The second input terminal of the ignition switch circuit is used to receive a first control signal. Correspondingly, the ignition switch circuit is used to control the conduction state of the first voltage conversion circuit according to the ignition switch signal and the first control signal. When the ignition switch signal indicates that the ignition switch is closed, or when the first control signal indicates that the first voltage conversion circuit is turned on, the ignition switch circuit controls the first voltage conversion circuit to turn on.

[0009] In this embodiment, in addition to the ignition switch signal, the ignition switch circuit can also be controlled by the first control signal, making the control of the ignition switch circuit more flexible and improving the applicability of the solution.

[0010] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the ignition switch circuit includes: a signal detection unit and a switch control unit. The first input terminal of the signal detection unit is used to receive the ignition switch signal, and the second input terminal of the signal detection unit is used to receive the first control signal. The signal detection unit is used to output a switch signal according to the ignition switch signal and the first control signal. The input terminal of the switch control unit is connected to the output terminal of the signal detection unit, and the output terminal of the switch control unit is connected to the enable terminal of the first voltage conversion circuit. The switch control unit is used to control the conduction state of the first voltage conversion circuit according to the switch signal.

[0011] In this embodiment, the ignition switch circuit can be implemented using a signal detection unit and a switch control unit, making the circuit design simpler.

[0012] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the signal detection unit includes: a first branch, a second branch, and a first switching transistor. The first end of the first branch is used to receive the ignition switch signal; the first end of the second branch is used to receive the first control signal; the first end of the first switching transistor is connected to a power supply; the enable end of the first switching transistor is connected to the second end of the first branch and the second end of the second branch, respectively; and the first end of the first switch is connected to the input end of the switch control unit.

[0013] In this embodiment, the ignition switch signal and the first control signal are received through different branches, and the first branch and the second branch are both connected to the enable terminal of the first switch transistor. This enables the switch transistor to be controlled by the ignition switch signal and the first control signal, thereby achieving the effect of outputting a switch signal according to the ignition switch signal and the first control signal.

[0014] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the switch control unit includes: a second switch transistor, the first end of the second switch transistor being connected to a power supply, the enable terminal of the second switch transistor being connected to the output terminal of the signal detection unit, and the first end of the second switch transistor being connected to the first voltage conversion circuit.

[0015] In this embodiment, the effect of a switch control unit can be achieved through a second switching transistor, simplifying the circuit design.

[0016] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the vehicle power supply circuit further includes: a second voltage conversion circuit, wherein the output terminal of the first voltage conversion circuit is connected to the main control module in the load through the second voltage conversion circuit, the enable terminal of the second voltage conversion circuit is used to receive a second control signal, and the second control signal is used to control the conduction state of the second voltage conversion circuit, and the second voltage conversion circuit is used to convert the target voltage into a first target voltage, wherein the first target voltage is the operating voltage of the main control module.

[0017] In this embodiment, voltage is converted using a two-stage voltage conversion circuit (first and second voltage conversion circuits), which reduces the load on a single voltage conversion circuit and improves circuit stability and safety. Furthermore, by extending the conduction state of the second voltage conversion circuit, the power supply state of the main control module can be controlled, making the power supply method for the main control module more flexible.

[0018] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the vehicle power supply circuit further includes: a third voltage conversion circuit, wherein the output terminal of the first voltage conversion circuit is connected to the control circuit in the load through the third voltage conversion circuit, and the third voltage conversion circuit is used to convert the target voltage into a second target voltage, wherein the second target voltage is the operating voltage of the control circuit.

[0019] In this embodiment, the control circuit in the load is powered by a third voltage conversion circuit, which can meet the operating voltage requirements of the control circuit and ensure the stability of the control circuit operation.

[0020] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the vehicle power supply circuit further includes: a fourth voltage conversion circuit and a camera power supply circuit. The fourth voltage conversion circuit is used to convert the voltage output by the power supply into a third target voltage, which is the operating voltage of the camera. The first input terminal of the camera power supply circuit is connected to the output terminal of the fourth voltage conversion circuit, the second input terminal of the camera power supply circuit is connected to the energy storage circuit, and the output terminal of the camera power supply circuit is used to connect to the camera. When the fourth voltage conversion circuit is in a conducting state, the camera power supply circuit uses the third target voltage output by the fourth voltage conversion circuit to power the camera; when the fourth voltage conversion circuit is in a non-conducting state, the camera power supply circuit uses the voltage input by the energy storage circuit to power the camera.

[0021] In this embodiment, the camera is powered by a fourth voltage conversion circuit and a camera power supply circuit. By controlling the conduction state of the fourth voltage conversion circuit, the power supply to the camera can be controlled, thus improving the flexibility of powering the camera.

[0022] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the camera power supply circuit includes: a power supply selection circuit, a switching circuit, and a camera power supply output circuit. The first input terminal of the power supply selection circuit is connected to the output terminal of the fourth voltage conversion circuit, and the second input terminal of the power supply selection circuit is connected to the energy storage circuit. The power supply selection circuit is used to select either the fourth voltage conversion circuit or the energy storage circuit to supply power to the camera. The input terminal of the switching circuit is connected to the output terminal of the power supply selection circuit, and the enable terminal of the switching circuit is used to receive a third control signal, wherein the third control signal controls the conduction state of the switching circuit. The input terminal of the camera power supply output circuit is connected to the output terminal of the switching circuit, and the output terminal of the camera power supply output circuit is used to connect to the camera. The camera power supply output circuit is used to stabilize the voltage output by the switch circuit and ensure that the camera power-on sequence is normal.

[0023] In this embodiment, the conduction state of the switching circuit is controlled by a third control signal, thereby controlling the conduction state of the fourth voltage conversion circuit, simplifying the circuit design and reducing its complexity. Furthermore, the camera power supply output circuit can stabilize the voltage output from the switching circuit and ensure normal camera power-on timing.

[0024] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the power supply selection circuit includes: a first diode and a second diode, wherein the anode of the first diode is connected to the output terminal of the fourth voltage conversion circuit, and the cathode of the first diode is connected to the input terminal of the switching circuit; the anode of the second diode is connected to the energy storage circuit, and the cathode of the second diode is connected to the input terminal of the switching circuit.

[0025] In this embodiment, the first diode and the second diode can ensure that the energy storage circuit will not output voltage to the fourth voltage conversion circuit, and the fourth voltage conversion circuit will not output voltage to the energy storage circuit, thereby improving the safety of the circuit.

[0026] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the camera power supply output circuit includes: an energy storage capacitor and a freewheeling resistor. The first end of the energy storage capacitor is connected to the output terminal of the switching circuit, and the second end of the energy storage capacitor is grounded. The energy storage capacitor is used to stabilize the voltage output by the output terminal of the switching circuit. The first end of the freewheeling resistor is connected to the output terminal of the switching circuit, and the second end of the freewheeling resistor is grounded. The freewheeling resistor is used to consume the charge stored in the energy storage capacitor when the switching circuit is disconnected, thereby ensuring that the camera power-on sequence is normal.

[0027] In this embodiment, the voltage output from the switch circuit can be stabilized by the energy storage capacitor, and the freewheeling resistor can ensure that the charge stored in the energy storage capacitor is consumed when the switch circuit is disconnected, thus ensuring the normal power-on sequence of the camera.

[0028] In conjunction with the technical solution provided in the first aspect above, in some possible implementations, the switching circuit includes: a third switching transistor, a first capacitor, and a second capacitor. The first terminal of the third switching transistor is connected to the output terminal of the power supply selection circuit, and the second terminal of the third switching transistor is connected to the input terminal of the camera power supply output circuit. The enable terminal of the third switching transistor is used to receive the third control signal, and the third control signal controls the conduction state of the third switching transistor. The first capacitor connects the enable terminal and the first terminal of the third switching transistor, or connects the enable terminal and the second terminal of the third switching transistor, and the first capacitor is used to protect the third switching transistor. The second capacitor connects the first terminal and the second terminal of the third switching transistor, and the second capacitor is used to protect the third switching transistor.

[0029] Secondly, this application provides a vehicle-mounted terminal, including a vehicle-mounted power supply circuit as described in the first aspect above and / or in combination with any possible implementation of the first aspect above.

[0030] Thirdly, this application provides a vehicle including an on-board terminal as described in the second aspect above and / or in combination with any possible implementation of the second aspect above. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a structural block diagram of a first type of vehicle power supply circuit shown in an embodiment of this application;

[0033] Figure 2 This is a structural block diagram of an ignition switch circuit shown in an embodiment of this application;

[0034] Figure 3 This is a circuit structure diagram of an ignition switch circuit shown in an embodiment of this application;

[0035] Figure 4 This is a structural block diagram of a camera power supply circuit shown in an embodiment of this application;

[0036] Figure 5 This is a structural block diagram of a second type of vehicle power supply circuit shown in an embodiment of this application. Detailed Implementation

[0037] The terms “first,” “second,” “third,” etc., are used only for distinguishing descriptions and do not indicate a sequence number, nor should they be interpreted as indicating or implying relative importance.

[0038] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0039] In the description of this application, it should be noted that the terms "inner", "outer", "left", "right", "upper", "lower", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0040] In the description of this application, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” shall be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a mechanical connection or an electrical connection; as a direct connection or an indirect connection through an intermediate medium; or as a connection within two components.

[0041] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings.

[0042] Please see Figure 1 , Figure 1 This is a structural block diagram of an on-board power supply circuit according to an embodiment of the present application. The on-board power supply circuit includes a first voltage conversion circuit and an ignition switch circuit.

[0043] The first voltage conversion circuit is used to convert the voltage output by the power supply into a target voltage, which is used to power the load.

[0044] The first voltage conversion circuit can be any type of voltage conversion circuit, and there are no restrictions on the specific structure and parameters of the voltage conversion circuit.

[0045] In one implementation, the first voltage conversion circuit can be connected to the power supply via a power protection circuit. The power protection circuit may include a common-mode filter circuit, a reverse connection protection circuit, and an overvoltage protection circuit, used to provide a stable and reliable power supply to the vehicle power supply circuit, reducing the failure rate of the vehicle terminal equipment and improving its stability and lifespan. The specific implementation methods and principles of the common-mode filter circuit, reverse connection protection circuit, and overvoltage protection circuit are well known to those skilled in the art and will not be elaborated upon here for the sake of brevity.

[0046] The first input terminal of the ignition switch circuit is used to receive the ignition switch signal output by the ignition switch. The output terminal of the ignition switch is connected to the enable terminal of the first voltage conversion circuit. The ignition switch circuit is used to control the conduction state of the first voltage conversion circuit according to the ignition switch signal.

[0047] Specifically, when the ignition switch signal indicates that the ignition switch is off, the ignition switch circuit controls the first voltage conversion circuit to disconnect. By controlling the conduction state of the first voltage conversion circuit based on the ignition switch signal, the ignition switch circuit can disconnect the first voltage conversion circuit when the ignition switch signal indicates that the ignition switch is off. This ensures that the power supply circuit stops working when the ignition switch is off, preventing the continuous consumption of the energy stored in the vehicle battery after the ignition switch is off, and thus preventing damage to the vehicle battery.

[0048] To make the control of the ignition switch circuit more flexible and improve the applicability of the solution, in one embodiment, the ignition switch circuit further includes a second input terminal. The second input terminal of the ignition switch circuit is used to receive the first control signal. Correspondingly, the ignition switch circuit is used to control the conduction state of the first voltage conversion circuit according to the ignition switch signal and the first control signal.

[0049] Specifically, when the ignition switch signal indicates that the ignition switch is closed, or when the first control signal indicates that the first voltage conversion circuit is turned on, the ignition switch circuit controls the first voltage conversion circuit to turn on. In addition to the ignition switch signal, the ignition switch circuit can also be controlled via the first control signal, making the control of the ignition switch circuit more flexible and expanding the applicability of this solution.

[0050] In one implementation, please refer to Figure 2 The ignition switch circuit may include a signal detection unit and a switch control unit.

[0051] The signal detection unit has a first input terminal for receiving an ignition switch signal and a second input terminal for receiving a first control signal. The signal detection unit outputs a switch signal based on the ignition switch signal and the first control signal.

[0052] In one implementation, the signal detection unit may include a first branch, a second branch, and a first switching transistor.

[0053] The first end of the first branch is used to receive the ignition switch signal.

[0054] To prevent other signals from flowing back from the first branch, the first branch may optionally include a diode, the anode of which is used to receive the ignition switch signal.

[0055] The first end of the second branch is used to receive the first control signal.

[0056] To prevent other signals from flowing back from the second branch, the second branch may optionally include a diode, the anode of which is used to receive the first control signal.

[0057] The first terminal of the first switching transistor is connected to the power supply, the enable terminal of the first switching transistor is connected to the second terminal of the first branch and the second terminal of the second branch respectively, and the first terminal of the first switch is connected to the input terminal of the switch control unit.

[0058] The first switching transistor can be a transistor, MOSFET, etc., and there is no restriction on the specific type of the first switching transistor.

[0059] For ease of understanding, let's take an NPN transistor as an example. The base of the NPN transistor is connected to the second terminal of the first branch and the second terminal of the second branch, respectively. The collector of the NPN transistor is connected to the input terminal of the switch control unit. The collector of the NPN transistor is also connected to the power supply through the first voltage divider resistor, and the emitter of the NPN transistor is grounded. When the base of the NPN transistor receives a high-level signal, the NPN transistor is turned on, and at this time, the collector of the NPN transistor is at a low-level signal. When the base of the NPN transistor receives a low-level signal, the NPN transistor is turned off, and at this time, the collector of the NPN transistor is at a high-level signal.

[0060] Optionally, when a backup power supply is available, the collector of the NPN transistor is also connected to the backup power supply through the first voltage divider resistor.

[0061] To prevent voltage transfer between the power supply and the backup power supply, optionally, the power supply can be connected to the first voltage divider resistor via a first protection diode, with the anode of the first protection diode connected to the power supply. Similarly, the backup power supply can be connected to the first voltage divider resistor via a second protection diode, with the anode of the second protection diode connected to the backup power supply.

[0062] The ignition switch signal and the first control signal are received through different branches. The first branch and the second branch are both connected to the enable terminal of the first switching transistor. This allows the switching transistor to be controlled by the ignition switch signal and the first control signal, thereby achieving the effect of outputting a switching signal based on the ignition switch signal and the first control signal.

[0063] Optionally, when the ignition switch circuit does not include a second input terminal, the signal detection unit may include a first branch and a first switching transistor. The first terminal of the first branch is used to receive the ignition switch signal. The first terminal of the first switching transistor is connected to a power supply, the enable terminal of the first switching transistor is connected to the second terminal of the first branch, and the first terminal of the first switch is connected to the input terminal of the switch control unit.

[0064] The switch control unit has its input terminal connected to the output terminal of the signal detection unit and its output terminal connected to the enable terminal of the first voltage conversion circuit. The switch control unit is used to control the conduction state of the first voltage conversion circuit according to the switch signal.

[0065] In one embodiment, the switch control unit includes a second switch transistor, the first end of which is connected to a power supply, the enable terminal of which is connected to the output terminal of a signal detection unit, and the first end of which is connected to a first voltage conversion circuit.

[0066] The second switching transistor can be a transistor, MOSFET, etc., and there is no restriction on the specific type of the second switching transistor.

[0067] For ease of understanding, let's take an NPN transistor as an example. The base of the NPN transistor is connected to the output of the signal detection unit, the collector is connected to the power supply through the second voltage divider resistor, and the emitter is grounded. When the base of the NPN transistor receives a high-level signal, the NPN transistor turns on. At this time, the power supply is grounded through the second voltage divider resistor, therefore, the collector of the NPN transistor outputs a low-level signal. When the base of the NPN transistor receives a low-level signal, the NPN transistor turns off. At this time, the power supply is connected to the first voltage conversion circuit through the second voltage divider resistor, that is, the collector of the NPN transistor outputs a high-level signal.

[0068] For a better understanding of the ignition switch circuit described above, please refer to [link / reference]. Figure 3 , Figure 3 This application provides a circuit diagram of an ignition switch circuit. It should be noted that... Figure 3 The ignition switch circuit shown is only one of many embodiments of the ignition switch circuit and should not be regarded as a limitation of this application.

[0069] like Figure 3 As shown, the first branch includes a first safety diode ( Figure 3 D1 shown), first resistor ( Figure 3 As shown in R1), the anode of the first safety diode is used to receive the ignition switch signal. Figure 3 As shown in ACC_IN), the cathode of the first safety diode is connected to the first terminal of the first resistor.

[0070] The second branch includes a second safety diode ( Figure 3 D2 shown), the second resistor ( Figure 3 As shown in R2), the anode of the second safety diode is used to receive the first control signal ( Figure 3 As shown in PWR_SYS), the cathode of the second safety diode is connected to the first end of the second resistor.

[0071] First switching transistor ( Figure 3 The base of T1 shown is connected to the second terminal of the first resistor and the second terminal of the second resistor, respectively. The base of the first switching transistor is also connected in parallel to a third resistor ( Figure 3 R3 and the first capacitor (shown) Figure 3 C1) is grounded. The third resistor and the first capacitor connected in parallel are used to filter the ignition switch signal input from the first branch and the first control signal input from the second branch.

[0072] The collector of the first switching transistor is connected to the first voltage divider resistor ( Figure 3 R4 (shown) and the first protection diode ( Figure 3D3 shown) and power supply ( Figure 3 The VIN shown is connected. The collector of the first switching transistor is also connected through the first voltage divider resistor (VIN). Figure 3 R4 shown) and the second protection diode ( Figure 3 D4 (shown) and backup power supply ( Figure 3 The BAT connection is shown.

[0073] The switch control unit includes a second switching transistor ( Figure 3 As shown in T2), the base of the second switch is connected to the fourth resistor ( Figure 3 R5 (shown) is connected to the collector of the first switching transistor. The collector of the second switching transistor is connected to the fifth resistor ( Figure 3 R6 (as shown) is connected to the power supply, and the collector of the second switching transistor is also connected to the enable terminal of the first voltage conversion circuit. The emitter of the second switching transistor is grounded.

[0074] In practical applications, when the car is ignited, the ignition switch signal is turned on (meaning the ignition switch signal is high level). The base potential of transistor T1 rises, and the collector and emitter of transistor T1 are in a conducting state. The signal detection unit outputs a low level to the switch control unit. Since the base potential of transistor T2 is low level, transistor T2 is in a cutoff state. VIN, through resistor R6, makes the collector of transistor T2 high level. Therefore, the ignition switch circuit outputs a high level. The high level makes the first voltage conversion circuit work normally, and the power supplies of the vehicle terminal work normally, and the equipment starts normally.

[0075] All power supplies of the vehicle terminal are in normal working condition, and the control circuit is also in normal working condition. At this time, the control circuit sets the first control signal to a high level, so that the ignition switch circuit controls the first voltage conversion circuit to always be in the conducting state.

[0076] At this time, even if the ignition switch signal is off (meaning the ignition switch signal is at a low level), since the first control signal is still at a high level, the ignition switch circuit still outputs a high level, the vehicle terminal still works normally, and can store the device's status, video recordings, and other information according to the user's settings.

[0077] According to the preset settings, after the required information operation is completed, the control circuit sets the first control signal to a low level. At this time, the ignition switch circuit outputs a low level, so that the vehicle terminal is in a power-off state.

[0078] Specifically, when the ignition switch signal is off and the control signal is at a low level, the base potential of transistor T1 is low, and transistor T1 is in the off state. The power supply VIN, through diode D3 and resistor R4, or the backup battery power supply BAT, through diode D4 and resistor R4, makes transistor T2 conduct. At this time, the collector and emitter of the transistor are conducting, the ignition switch circuit outputs a low level, and the low level makes the first voltage conversion circuit turn off. The power supplies of the vehicle terminal will be cut off, and the vehicle terminal will be in a power-off state, making the power consumption of the vehicle equipment extremely low. The loss to the vehicle battery is negligible, effectively protecting the vehicle power supply and preventing the vehicle battery from being damaged by depletion.

[0079] The examples provided are for illustrative purposes only and should not be construed as limiting the scope of this application.

[0080] To reduce the stress on the first voltage conversion circuit, in one embodiment, the vehicle power supply circuit may further include a second voltage conversion circuit.

[0081] The output of the first voltage conversion circuit is connected to the main control module in the load through the second voltage conversion circuit. The enable terminal of the second voltage conversion circuit is used to receive the second control signal and control the conduction state of the second voltage conversion circuit through the second control signal. The second voltage conversion circuit is used to convert the target voltage into the first target voltage, and the first target voltage is the working voltage of the main control module.

[0082] The main control module is part of the vehicle terminal and is used to run the operating system of the vehicle terminal.

[0083] By using a two-stage voltage conversion circuit (first and second voltage conversion circuits) to convert voltage, the load on a single voltage conversion circuit can be reduced, improving circuit stability and safety. Furthermore, by extending the conduction state of the second voltage conversion circuit, the power supply status of the main control module can be controlled, making the power supply method for the main control module more flexible.

[0084] The second voltage conversion circuit can be any type of voltage conversion circuit, and there are no restrictions on the specific structure and parameters of the voltage conversion circuit.

[0085] Correspondingly, the backup power supply can be charged through the first voltage conversion circuit at this time.

[0086] To ensure that the control circuit is always in a stable working state, in one embodiment, the vehicle power supply circuit further includes a third voltage conversion circuit. The output terminal of the first voltage conversion circuit is connected to the control circuit in the load through the third voltage conversion circuit. The third voltage conversion circuit is used to convert the target voltage into a second target voltage, which is the operating voltage of the control circuit.

[0087] By supplying power to the control circuit in the load through a third voltage conversion circuit, the operating voltage requirements of the control circuit can be met, ensuring the stability of its operation. Furthermore, since the voltage conversion circuits supplying power to the control circuit and the main control module are different, no malfunction will occur even if the required operating voltages for the control circuit and the main control module differ.

[0088] The third voltage conversion circuit can be any type of voltage conversion circuit, and there are no restrictions on the specific structure and parameters of the voltage conversion circuit.

[0089] Since a camera may be present in the vehicle, it can also be powered by an onboard power supply circuit. In one embodiment, the onboard power supply circuit further includes a fourth voltage conversion circuit and a camera power supply circuit.

[0090] The fourth voltage conversion circuit is used to convert the voltage output by the power supply into the third target voltage, which is the operating voltage of the camera.

[0091] The fourth voltage conversion circuit can be any type of voltage conversion circuit, and there are no restrictions on the specific structure and parameters of the voltage conversion circuit.

[0092] The first input terminal of the camera power supply circuit is connected to the output terminal of the fourth voltage conversion circuit, the second input terminal of the camera power supply circuit is connected to the energy storage circuit, and the output terminal of the camera power supply circuit is used to connect to the camera.

[0093] The camera is powered by a fourth voltage conversion circuit and a camera power supply circuit. By controlling the conduction state of the fourth voltage conversion circuit, the power supply to the camera can be controlled, thus improving the flexibility of powering the camera.

[0094] In one implementation, such as Figure 4 As shown, the camera power supply circuit includes a power selection circuit, a switching circuit, and a camera power output circuit.

[0095] When an energy storage circuit is present, the first input terminal of the power supply selection circuit is connected to the output terminal of the fourth voltage conversion circuit, and the second input terminal of the power supply selection circuit is connected to the energy storage circuit. The power supply selection circuit is used to select the fourth voltage conversion circuit or the energy storage circuit to power the camera.

[0096] Optionally, the power supply selection circuit may include a first signal transmission line and a second signal transmission line. The first signal transmission line is used to connect to a power source, and the second signal transmission line is used to connect to an energy storage circuit.

[0097] To improve circuit safety, in one implementation, the power supply selection circuit may include a first diode and a second diode.

[0098] The anode of the first diode is connected to the output terminal of the fourth voltage conversion circuit, and the cathode of the first diode is connected to the input terminal of the switching circuit. The anode of the second diode is connected to the energy storage circuit, and the cathode of the second diode is connected to the input terminal of the switching circuit. The first and second diodes ensure that the energy storage circuit does not output voltage to the fourth voltage conversion circuit, and vice versa, thus improving circuit safety.

[0099] Optionally, when there is no energy storage circuit, the power supply selection circuit may not be set in the camera power supply circuit. In this case, the camera power supply circuit includes a switching circuit and a camera power supply output circuit.

[0100] The input terminal of the switching circuit is connected to the output terminal of the power supply selection circuit. The enable terminal of the switching circuit is used to receive a third control signal, which controls the conduction state of the switching circuit.

[0101] The switching circuit may include transistors such as triodes and MOSFETs that can be used as switches.

[0102] Taking a switching circuit including a PMOS transistor as an example, the gate of the PMOS transistor is used to receive the third control signal, the source of the PMOS transistor is connected to the output terminal of the power supply selection circuit, and the drain of the PMOS transistor is connected to the input terminal of the camera power supply output circuit. This example is for illustrative purposes only and should not be construed as a limitation of this application.

[0103] To protect the circuit, in one embodiment, the switching circuit includes a third switching transistor, a first capacitor, and a second capacitor.

[0104] The third switch has its first terminal connected to the output terminal of the power supply selection circuit, and its second terminal connected to the input terminal of the camera power supply output circuit. The enable terminal of the third switch is used to receive the third control signal, which controls the conduction state of the third switch.

[0105] The third switching transistor can be a transistor, MOSFET, or other transistor that can be used as a switch.

[0106] The first capacitor is connected to the enable terminal and the first terminal of the third switch transistor, or it is connected to the enable terminal and the second terminal of the third switch transistor. The first capacitor is used to protect the third switch transistor.

[0107] For example, when the third switch is a MOSFET, the first capacitor is connected to the gate and source of the MOSFET.

[0108] The second capacitor connects the first and second terminals of the third switch and is used to protect the third switch.

[0109] For example, when the third switch is a MOSFET, the first capacitor is connected to the drain and source of the MOSFET.

[0110] For example, when a switching circuit includes a field-effect transistor (FET), a high inrush current will occur at the instant the FET turns on, because the voltage across the energy storage capacitor in the camera's power supply output circuit cannot change abruptly. This inrush current may damage the FET or trigger the overcurrent protection of the preceding power supply. Simultaneously, this inrush current will cause the voltage supplying the camera to drop. The turn-on process of a FET is mainly affected by its gate-source capacitance (Cgs) and its source-drain capacitance (Cgd). Therefore, the switching circuit can also include gate-source capacitors and source-drain capacitors. The gate-source capacitor connects the gate and drain of the FET, and the source-drain capacitor connects the source and drain of the FET, thereby achieving a slow-turn-on function for the FET, protecting it, and ensuring that the voltage supplying the camera is not pulled down. Specifically, the selection of gate-source capacitors and source-drain capacitors should be based on actual needs. If the capacitance values ​​of the gate-source capacitors and source-drain capacitors are too small, the turn-on time will be too short, failing to protect the MOSFET and stabilize the camera's power supply voltage. If the capacitance values ​​of the gate-source capacitors and source-drain capacitors are too large, the turn-on time will be too long, increasing the MOSFET's losses and potentially causing the MOSFET to overheat and burn out.

[0111] The input terminal of the camera power supply output circuit is connected to the output terminal of the switching circuit. The output terminal of the camera power supply output circuit is used to connect to the camera. The camera power supply output circuit is used to stabilize the voltage output by the switching circuit and ensure that the camera power-on sequence is normal.

[0112] In one implementation, the camera power supply output circuit may include a storage capacitor and a freewheeling resistor.

[0113] Energy storage capacitors are generally capacitors in the μF range or larger. If the capacitance value of the energy storage capacitor is too small, it will not be able to achieve the effect of storing energy and stabilizing the voltage. If the capacitance value is too large, it will cause the energy storage time to be consumed too long when the switching circuit is turned off.

[0114] When selecting a freewheeling resistor, the resistance value, package, and power rating should be considered comprehensively to prevent excessive power and resistor burnout.

[0115] The first terminal of the energy storage capacitor is connected to the output terminal of the switching circuit, and the second terminal of the energy storage capacitor is grounded. The energy storage capacitor is used to stabilize the voltage output by the switching circuit.

[0116] The energy storage capacitor can be any type of capacitor, and there are no restrictions on the specific model of the energy storage capacitor.

[0117] The freewheeling resistor has its first end connected to the output of the switching circuit and its second end grounded. The freewheeling resistor is used to dissipate the charge stored in the energy storage capacitor when the switching circuit is turned off, ensuring that the camera's power-on sequence is normal.

[0118] The freewheeling resistor can be any type of resistor; there are no restrictions on the specific model of the freewheeling resistor.

[0119] The energy storage capacitor can stabilize the output voltage of the switching circuit. The freewheeling resistor can ensure that the charge stored in the energy storage capacitor is consumed when the switching circuit is turned off, thus ensuring that the camera power-on sequence is normal.

[0120] In practical operation, the conduction state of the switching circuit is controlled by the third control signal, thereby controlling the conduction state between the fourth voltage conversion circuit or energy storage circuit and the camera. This simplifies the circuit design and reduces circuit complexity. Furthermore, the camera power supply output circuit can stabilize the voltage output from the switching circuit and ensure the camera's power-on sequence is normal.

[0121] For a better understanding of the above-described vehicle power supply circuit, please refer to [link / reference]. Figure 5 It is important to note that Figure 5 The vehicle power supply circuit shown is only one of many embodiments of the vehicle power supply circuit provided in this application and should not be regarded as a limitation of this application.

[0122] like Figure 5 As shown, the vehicle power supply circuit includes a power protection circuit, a first voltage conversion circuit, an ignition switch circuit, a second voltage conversion circuit, a third voltage conversion circuit, a fourth voltage conversion circuit, a camera power supply circuit, and an energy storage circuit. Figure 5 The connection relationships between the various circuits shown and their specific implementation principles have been clearly described above and will not be repeated here.

[0123] Optionally, the first control signal received by the ignition switch circuit, the second control signal received by the second voltage conversion circuit, and the third control signal received by the camera power supply circuit can all be sent by a control circuit connected to the third voltage conversion circuit.

[0124] In practical applications, when the ignition switch circuit receives an ignition switch signal indicating that the ignition switch is closed, the ignition switch circuit controls the first voltage conversion circuit to turn on.

[0125] The first voltage conversion circuit converts the voltage to charge the energy storage circuit. Simultaneously, the third voltage conversion circuit operates normally, supplying power to the control circuit to ensure its proper startup and operation.

[0126] After the control circuit starts, it checks whether the vehicle terminal device lock is in the closed state. If it is not closed, the control circuit sends a second control signal to the second voltage conversion circuit, preventing the second voltage conversion circuit from conducting and thus preventing the vehicle terminal from starting normally. Then, it continues to check whether the vehicle terminal device lock is in the closed state. The vehicle terminal device lock is used to prevent unauthorized personnel from opening the vehicle terminal and performing accidental operations, protecting the vehicle terminal from damage.

[0127] If the vehicle terminal device is locked, the control circuit uses its own ADC to determine whether the voltage output by the vehicle power supply circuit is within the normal operating range. This normal operating range can be preset and can be directly accessed when needed.

[0128] Optionally, there are two common automotive power supply voltages: 12V and 24V. For the 12V system, the normal operating voltage range of the vehicle power supply circuit is generally 9V to 16V, which users can set according to their actual needs. For the 24V system, the normal operating voltage range of the vehicle power supply circuit is generally 19V to 28V, which users can set according to their actual needs.

[0129] If it is not within the normal operating range, there are two situations: undervoltage and overvoltage.

[0130] If the voltage is low, the control circuit controls the second voltage conversion circuit to conduct for a preset time to allow the main control module to start normally for the preset time, thus enabling the vehicle terminal to start normally. After the vehicle terminal starts, it displays a warning message related to low voltage shutdown. After the preset time, the vehicle terminal shuts down. The preset time can be set according to the user's actual needs, such as 5 seconds, 10 seconds, etc., and there is no limitation on it here.

[0131] In case of overvoltage, the overvoltage protection circuit in the power supply protection circuit will disconnect the power supply to the main control module to prevent irreversible damage to the vehicle terminal.

[0132] If the voltage output by the vehicle power supply circuit is within the normal operating range, the control circuit controls the second voltage conversion circuit to turn on, supplying power to the main control module so that the vehicle terminal can start normally.

[0133] After the vehicle terminal starts up normally, it can be determined whether its own storage hard drive temperature is within the normal startup temperature range.

[0134] Since the normal startup temperature of a storage hard drive needs to be above 0°C, a temperature below 0°C can easily cause the storage hard drive to fail to start normally, thus preventing video recording from being stored. It can be set that when the storage hard drive temperature is below 0°C, the storage hard drive heating circuit starts working, and when the storage hard drive temperature is above 5°C, the storage hard drive heating circuit stops working, and the storage hard drive temperature reaches the normal startup temperature.

[0135] If not, the storage hard drive heating circuit starts working to heat the hard drive, the main control module does not start, and it continues to check whether the storage hard drive temperature is within the normal startup range.

[0136] If the storage hard drive temperature is within the normal startup temperature range, the system starts normally, and then the control circuit controls the fourth voltage conversion circuit to conduct.

[0137] At the same time, the control circuit controls the camera power supply circuit to work normally, so as to supply power to the camera through the fourth voltage conversion circuit and enable the camera to start normally.

[0138] The control circuit activates the second voltage conversion circuit. This second voltage conversion circuit converts the voltage output from the first voltage conversion circuit into the target voltage, which then powers the main control module.

[0139] Based on the same inventive concept, this application also provides a vehicle-mounted terminal, which includes a vehicle-mounted power supply circuit.

[0140] The specific implementation method of the vehicle power supply circuit is the same as that of the aforementioned vehicle power supply circuit, and will not be repeated here for the sake of brevity.

[0141] Based on the same inventive concept, this application also provides a means of transportation that includes the aforementioned vehicle-mounted terminal.

[0142] The means of transportation include cars, trains, ships, aircraft, etc. The examples above are for illustrative purposes only and should not be construed as limiting this application.

[0143] The specific implementation method of the vehicle terminal is the same as that of the aforementioned vehicle terminal, and will not be repeated here for the sake of brevity.

[0144] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A vehicle-mounted power supply circuit, characterized in that, include: A first voltage conversion circuit is used to convert the voltage output by the power supply into a target voltage, which is used to supply power to the load. An ignition switch circuit is provided, wherein a first input terminal of the ignition switch circuit is used to receive an ignition switch signal output by an ignition switch, and the output terminal of the ignition switch is connected to the enable terminal of a first voltage conversion circuit. The ignition switch circuit is used to control the conduction state of the first voltage conversion circuit according to the ignition switch signal, wherein when the ignition switch signal indicates that the ignition switch is off, the ignition switch circuit controls the first voltage conversion circuit to be off. The second voltage conversion circuit is connected to the main control module in the load through the output terminal of the first voltage conversion circuit. The enable terminal of the second voltage conversion circuit is used to receive a second control signal and control the conduction state of the second voltage conversion circuit through the second control signal. The second voltage conversion circuit is used to convert the target voltage into a first target voltage, which is the operating voltage of the main control module. A third voltage conversion circuit is used to convert the target voltage into a second target voltage, where the output of the first voltage conversion circuit is connected to the control circuit in the load. The third voltage conversion circuit is used to convert the target voltage into a second target voltage, where the second target voltage is the operating voltage of the control circuit. The fourth voltage conversion circuit is used to convert the voltage output by the power supply into a third target voltage, which is the operating voltage of the camera. A camera power supply circuit, wherein the first input terminal of the camera power supply circuit is connected to the output terminal of the fourth voltage conversion circuit, the second input terminal of the camera power supply circuit is connected to the energy storage circuit, and the output terminal of the camera power supply circuit is used to connect to the camera; Specifically, when the fourth voltage conversion circuit is in the conducting state, the camera power supply circuit uses the third target voltage output by the fourth voltage conversion circuit to power the camera; when the fourth voltage conversion circuit is in the non-conducting state, the camera power supply circuit uses the voltage input by the energy storage circuit to power the camera. The ignition switch circuit includes: A signal detection unit, wherein a first input terminal of the signal detection unit is used to receive the ignition switch signal, a second input terminal of the signal detection unit is used to receive a first control signal, and the signal detection unit is used to output a switch signal according to the ignition switch signal and the first control signal; A switch control unit is provided, wherein the input terminal of the switch control unit is connected to the output terminal of the signal detection unit, and the output terminal of the switch control unit is connected to the enable terminal of the first voltage conversion circuit. The switch control unit is used to control the conduction state of the first voltage conversion circuit according to the switch signal; wherein, when the ignition switch signal indicates that the ignition switch is closed, or the first control signal indicates that the first voltage conversion circuit is turned on, the switch control unit controls the first voltage conversion circuit to be turned on.

2. The vehicle power supply circuit according to claim 1, characterized in that, The signal detection unit includes: The first branch, the first end of the first branch is used to receive the ignition switch signal; The second branch, the first end of which is used to receive the first control signal; The first switch transistor has its first end connected to the power supply, its enable end connected to the second end of the first branch and the second end of the second branch, and its first end connected to the input end of the switch control unit.

3. The vehicle power supply circuit according to claim 1, characterized in that, The switch control unit includes: The second switching transistor has its first terminal connected to the power supply, its enable terminal connected to the output terminal of the signal detection unit, and its first terminal connected to the first voltage conversion circuit.

4. The vehicle power supply circuit according to claim 1, characterized in that, The camera power supply circuit includes: A power supply selection circuit is provided, wherein the first input terminal of the power supply selection circuit is connected to the output terminal of the fourth voltage conversion circuit, and the second input terminal of the power supply selection circuit is connected to the energy storage circuit. The power supply selection circuit is used to select the fourth voltage conversion circuit or the energy storage circuit to supply power to the camera. A switching circuit, wherein the input terminal of the switching circuit is connected to the output terminal of the power supply selection circuit, and the enable terminal of the switching circuit is used to receive a third control signal, wherein the conduction state of the switching circuit is controlled by the third control signal. A camera power supply output circuit is provided, wherein the input terminal of the camera power supply output circuit is connected to the output terminal of the switching circuit, the output terminal of the camera power supply output circuit is used to connect to the camera, and the camera power supply output circuit is used to stabilize the voltage output by the output terminal of the switching circuit and ensure that the camera power-on sequence is normal.

5. The vehicle power supply circuit according to claim 4, characterized in that, The power supply selection circuit includes: The first diode has its anode connected to the output terminal of the fourth voltage conversion circuit and its cathode connected to the input terminal of the switching circuit. The second diode has its anode connected to the energy storage circuit and its cathode connected to the input terminal of the switching circuit.

6. The vehicle power supply circuit according to claim 4, characterized in that, The camera power supply output circuit includes: An energy storage capacitor, the first end of which is connected to the output terminal of the switching circuit, and the second end of which is grounded, is used to stabilize the voltage output by the output terminal of the switching circuit. A freewheeling resistor is provided, with its first end connected to the output terminal of the switching circuit and its second end grounded. The freewheeling resistor is used to consume the charge stored in the energy storage capacitor when the switching circuit is turned off, thereby ensuring that the camera's power-on sequence is normal.

7. The vehicle power supply circuit according to claim 4, characterized in that, The switching circuit includes: The third switch has its first terminal connected to the output terminal of the power supply selection circuit and its second terminal connected to the input terminal of the camera power supply output circuit. The enable terminal of the third switch is used to receive the third control signal and control the conduction state of the third switch through the third control signal. A first capacitor is used to connect the enable terminal of the third switch to the first terminal, or the first capacitor is used to connect the enable terminal of the third switch to the second terminal. The first capacitor is used to protect the third switch. The second capacitor is connected to the first and second terminals of the third switch, and the second capacitor is used to protect the third switch.

8. A vehicle-mounted terminal, characterized in that, include: The vehicle power supply circuit as described in any one of claims 1-7.

9. A means of transportation, characterized in that, Including the vehicle-mounted terminal as described in claim 8.

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