Vehicle-mounted USB (Universal Serial Bus) power supply anti-backflow circuit and vehicle-mounted machine system

Abstract

The utility model discloses a vehicle-mounted USB power supply anti-backflow circuit and a vehicle-mounted infotainment system, a trigger circuit receives a signal of a working mode of the vehicle-mounted infotainment system, and outputs an electric signal to a control circuit according to the working signal, so as to control the on-off of a switching circuit to prevent the backflow of a power supply. According to the technical scheme of the utility model, the anti-backflow of the USB power supply of the vehicle-mounted machine system to the external power supply is realized, the effective control of the switching circuit can be ensured no matter in a power-on state or a power-off state, and the direct short circuit of the external power supply and the USB power supply in the vehicle-mounted machine system is avoided, so that the damage to components or external debugging equipment caused by voltage backflow when a host is powered off or restarted is avoided.

Description

Technical Field

[0001] The present application relates to the field of lighting equipment, and in particular to a vehicle-mounted USB power supply backflow prevention circuit and a vehicle computer system. Background Art

[0002] Currently, most in-vehicle smart cockpit systems include USB function ports. Some USB ports also include development and debugging functions. At the same time, some customers require a short-circuit test of the USB port pin to the battery when the computer is turned off. However, in the vehicle system, there is no anti-reverse circuit between the power circuit and the USB interface, resulting in a direct short circuit between the power circuit and the power device. This causes the power of the power device to flow back into the host, which can easily damage components or external debugging computers. Utility Model Content

[0003] In order to solve the technical problem that no anti-reverse circuit is set between the power circuit and the USB interface described in the background technology, resulting in a direct short circuit between the power circuit and the power device, so that the power of the power device is backflowed into the host, which is easy to damage components or external power devices, the present application provides a vehicle-mounted USB power anti-reverse circuit and a vehicle-machine system.

[0004] First,

[0005] The present application provides a vehicle-mounted USB power supply anti-backflow circuit, the circuit comprising:

[0006] A switch circuit is provided with a first connection end, a second connection end, and a first enabling end, wherein the first connection end is connected to the power circuit, and the second connection end is connected to the power device through the USB circuit;

[0007] A trigger circuit is connected to the vehicle computer system to obtain a working signal;

[0008] And a control circuit, which is respectively connected to the first enabling end and the trigger circuit, is used to obtain a working signal of the trigger circuit and output an electrical signal to the control circuit according to the working signal, thereby controlling the on and off of the switch circuit to prevent power backflow.

[0009] In some embodiments, the switch circuit includes a first MOS tube, a gate of the first MOS tube is an enable terminal connected to the control circuit, a source is a second connection terminal connected to the USB circuit, and a drain is a first connection terminal connected to the power circuit.

[0010] In some embodiments, the switch circuit further includes a first capacitor, one end of the first capacitor is connected to the drain of the first MOS tube, and the other end of the first capacitor is grounded.

[0011] In some embodiments, the switch circuit further includes a first resistor, one end of the first resistor is connected to the source of the first MOS transistor, and the first resistor is connected to the gate of the first MOS transistor.

[0012] In some embodiments, the control circuit includes a first voltage divider circuit, a first enabling circuit, and a second voltage divider circuit;

[0013] The first enabling circuit is provided with a second enabling terminal, a third connecting terminal and a fourth connecting terminal. The second enabling terminal is connected to the trigger circuit through a first voltage dividing circuit, the third connecting terminal is connected to the first enabling terminal of the switch circuit through the second voltage dividing circuit, and the fourth connecting terminal is grounded.

[0014] In some embodiments, the first enabling circuit is a MOS transistor or a PNP transistor.

[0015] In some embodiments, the first voltage divider circuit includes a second resistor and a third resistor connected to the second enable terminal, the other end of the second resistor is connected to the trigger circuit, and the other end of the third resistor is grounded.

[0016] In some embodiments, the second voltage divider circuit includes a fourth resistor, one end of the fourth resistor is connected to the third connection end and the other end of the fourth resistor is connected to the gate of the first MOS transistor.

[0017] In some embodiments, the trigger circuit includes a control chip, which is provided with a detection end and a control end. The detection end is connected to the vehicle system, and the control end is connected to the control circuit; the control chip is used to obtain the working signal of the host of the vehicle system and convert it into an electrical signal to control the control circuit.

[0018] Second,

[0019] The present application provides a vehicle system, including the above-mentioned vehicle-mounted USB power anti-backflow circuit, power supply circuit, and USB circuit. The vehicle-mounted USB power anti-backflow circuit is connected between the power supply circuit and the USB circuit and is connected to an external power supply device through the USB circuit.

[0020] As can be seen from the above, a vehicle-mounted USB power backflow prevention circuit and vehicle system in the present application receive the signal of the working mode of the vehicle system through a trigger circuit, and output an electrical signal to the control circuit according to the working signal, thereby controlling the on and off of the switch circuit to prevent power backflow. The vehicle system USB power supply can prevent backflow of the external power supply, whether in the power-on state or the power-off state, and can ensure effective control of the switch circuit to avoid direct short circuit between the external power supply and the internal USB power supply of the vehicle system, resulting in voltage backflow when the host is shut down or restarted, thereby damaging components or external debugging equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural schematic diagram of a first embodiment of a vehicle-mounted USB power supply anti-backflow circuit provided in Example 1 of the present application.

[0022] Figure 2 This is a circuit schematic diagram of a second embodiment of a vehicle-mounted USB power supply anti-backflow circuit provided in Example 2 of the present application.

[0023] Figure 3 A structural schematic diagram of a vehicle system provided in Example 3 of the present application.

[0024] Markings in the figure:

[0025] 110, switch circuit; 120, control circuit; 130, trigger circuit; 140, USB circuit; 150, power circuit; 160, power supply device;

[0026] MCU, control chip, Q1, first MOS tube, Q2, second MOS tube, R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; C1, first capacitor;

[0027] 210. Vehicle computer system; 220. Vehicle USB power anti-backflow circuit. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present application are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer definition of the protection scope of the present application.

[0029] Please refer to the drawings, where the same component symbols represent the same components, and the principles of the present application are illustrated by implementing them in an appropriate computing environment. The following description is based on the illustrated specific embodiments of the present application, which should not be considered as limiting other specific embodiments of the present application that are not described in detail herein.

[0030] The term "module" as used herein may be a software or hardware object executed on the computing system. The different components, modules, engines, and services described herein may be implementation objects on the computing system. The apparatus and methods described herein may be implemented in software, or in hardware, and all are within the scope of protection of this application.

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0033] Embodiment 1,

[0034] Figure 1 The first embodiment of a vehicle-mounted USB power supply anti-backflow circuit of the present application is shown, and the circuit is applied to a vehicle environment such as a vehicle system 210 or a smart cockpit. The circuit includes a switch circuit 110, a control circuit 120, and a trigger circuit 130, wherein the switch circuit 110 is provided with a first connection terminal, a second connection terminal, and a first enabling terminal, the first connection terminal is connected to the power circuit 150, and the second connection terminal is connected to the power supply device 160 through the USB circuit 140; the power supply circuit 150 can be a battery and a power chip connected to the battery output terminal, and the power supply circuit 150 is used to power various electrical appliances of the vehicle system 210. The power supply device 160 can be a debugging device for testing, upgrading, and burning, and the power supply device 160 can also be a mobile terminal for charging and communication, and the mobile terminal can be a mobile phone, a tablet, a watch, etc.

[0035] The control circuit 120 is connected to the enable terminal and the trigger circuit 130 respectively. The trigger circuit 130 is connected to the vehicle system 210 to obtain the working signal and output the electrical signal to the control circuit 120 according to the working signal, thereby controlling the switch circuit 110 to be turned on and off to prevent the power from flowing back. The USB power supply of the vehicle system 210 is prevented from flowing back to the external power supply. Whether in the power-on state or the power-off state, the switch circuit 110 can be effectively controlled to avoid a direct short circuit between the external power supply and the internal USB power supply of the vehicle system 210, which causes the voltage to flow back when the host is shut down or restarted, thereby damaging components or external debugging equipment.

[0036] Embodiment 2,

[0037] Figure 2 The second embodiment of a vehicle-mounted USB power supply anti-backflow circuit 220 of the present application is shown. This embodiment is based on embodiment 1 and provides a specific implementation method of the circuit. The circuit includes a switch circuit 110, a control circuit 120, and a trigger circuit 130. The switch circuit 110 is provided with a first connection end, a second connection end, and a first enable end. The first connection end is connected to the power circuit 150, and the second connection end is connected to the power supply device 160 through the USB circuit 140; the control circuit 120 is respectively connected to the enable end and the trigger circuit 130. The trigger circuit 130 is connected to the vehicle system 210 to obtain a working signal and output an electrical signal to the control circuit 120 according to the working signal, thereby controlling the switch circuit 110 to be turned on and off to prevent power backflow. The switch circuit 110 includes a first MOS tube Q1, the gate of the first MOS tube Q1 is connected to the control circuit 120 as the enable end, the source level is connected to the USB circuit 140 as the second connection end, and the drain level is connected to the power circuit 150 as the first connection end. The present application discloses a vehicle-mounted USB power supply backflow prevention circuit and vehicle-mounted system, which receives a signal of the working mode of the vehicle-mounted system through a trigger circuit, and outputs an electrical signal to the control circuit according to the working signal, thereby controlling the on-off of the switch circuit to prevent the power from backflowing. The vehicle-mounted system USB power supply can prevent the backflow of the external power supply, and whether it is in the on state or the off state, it can ensure the effective control of the switch circuit, avoid the direct short circuit between the external power supply and the internal USB power supply of the vehicle-mounted system, and cause the voltage to backflow when the host is shut down or restarted, thereby damaging components or external debugging equipment.

[0038] In some embodiments, the switch circuit 110 further includes a first capacitor C1, one end of the first capacitor C1 is connected to the drain of the first MOS tube Q1, and the other end of the first capacitor C1 is grounded. The present application filters the input end of the switch circuit 110 through the first capacitor C1 to protect the first MOS tube Q1. The switch circuit 110 further includes a first resistor R1, one end of the first resistor R1 is connected to the source Q1_S of the first MOS tube Q1, and the first resistor R1 is connected to the gate of the first MOS tube Q1. The present application provides a bias voltage through a field effect tube, and at the same time acts as a discharge resistor to protect the gate of the first MOS tube Q1 and the source of the first MOS tube Q1.

[0039] In some embodiments, the control circuit 120 includes a first voltage divider circuit, a first enabling circuit, and a second voltage divider circuit; the first enabling circuit is provided with a second enabling terminal, a third connecting terminal, and a fourth connecting terminal, the second enabling terminal is connected to the trigger circuit 130 through the first voltage divider circuit, the third connecting terminal is connected to the first enabling terminal of the switch circuit 110 through the second voltage divider circuit, and the fourth connecting terminal is grounded. The first enabling circuit is a MOS tube or a PNP transistor. The first voltage divider circuit includes a second resistor R2 and a third resistor R3 connected to the second enabling terminal, the other end of the second resistor R2 is connected to the trigger circuit 130, and the other end of the third resistor R3 is grounded. The second voltage divider circuit includes a fourth resistor R4, one end of the fourth resistor R4 is connected to the third connecting terminal and the other end is connected to the gate of the first MOS tube Q1. In this embodiment, the second resistor R2, the third resistor R3, and the fourth resistor R4 are used for voltage division, and the first enabling circuit can be a PNP transistor. The first enabling circuit is turned on by the trigger circuit 130, so that the gate signal of the first MOS tube Q1 can be pulled low, thereby preventing the vehicle system 210 USB power supply from backflowing to the external power supply.

[0040] In some embodiments, the trigger circuit 130 includes a control chip MCU, which is provided with a detection end and a control end. The detection end is connected to the vehicle system 210, and the control end is connected to the control circuit 120; the control chip MCU is used to obtain the working signal of the host of the vehicle system 210, and convert it into an electrical signal to control the control circuit 120. In this embodiment, the control chip MCU can be a chip of model FS32K146, and the detection end of the control chip MCU obtains the working state of the vehicle system 210 by connecting to the vehicle CAN bus, the power ACC module, or the USB circuit 140, and outputs an electrical signal to the control circuit 120 according to the working state. In an example, the working mode of the vehicle system 210 can be a normal startup mode, a debugging mode, and a shutdown mode. In the normal startup mode, the control end outputs a high level to turn on the switch circuit 110. In the debugging mode and the shutdown mode, the control end outputs a low level to turn off the switch circuit 110. Among them, the control chip MCU can be a permanently powered chip to realize the control of the switch circuit 110 when the vehicle system 210 is turned off or ignited.

[0041] In the above embodiment, a first voltage divider circuit is added between the trigger circuit 130 and the first enabling circuit, so that the control chip MCU is connected to the second enabling terminal of the second enabling circuit through the second resistor R2, and the switch circuit 110 is controlled by the second enabling circuit. The second enabling circuit is a first triode.

[0042] In the present application scheme, in a specific application scenario, the current in-vehicle intelligent cockpit system basically includes a USB function port, and some USB ports also include development and debugging functions. At the same time, some customers require that the USB port pins be tested for short circuit to the battery when the power is off, so an anti-backflow circuit as shown in the figure below is added. In addition to the above scenarios, the vehicle USB circuit can be connected to other electrical devices, which can also play an anti-backflow function. Specifically, in the normal boot mode, the detection end of the control chip MCU causes the control end of the control chip MCU to output a high level such as 3.3V, so that the third connection end and the fourth connection end of the first transistor are connected to each other, thereby turning on the first MOS tube Q1 and the USB power is output normally.

[0043] In the debugging mode, the detection end of the control chip MCU causes the control end of the control chip MCU to output a low level, so that the first transistor is turned off, and then the first MOS tube Q1 is controlled to be turned off. At the same time, the body diode of the first MOS tube Q1 faces outward, that is, the first MOS tube Q1 cuts off the path for the external power supply to enter the host, so that the external power supply cannot be backflowed into the host.

[0044] When switching from normal startup mode to shutdown mode, the control end of the control chip MCU first outputs a low level to turn off the first transistor and the first MOS tube Q1, and then turns off other power supplies in the host to prevent external voltage from flowing back into the host during the shutdown process.

[0045] In shutdown mode, the control terminal of the control chip MCU maintains a low level, and the first transistor and the first MOS tube Q1 remain in the off state. That is, by effectively controlling the first transistor, the problem of the external power supply and the internal power supply being directly short-circuited in the original circuit and backflowing into the host is solved.

[0046] Embodiment 3,

[0047] Figure 3The first embodiment of a vehicle system 210 of the present application is shown, including the vehicle USB power anti-backflow circuit 220, the power circuit 150, and the USB circuit 140 described in embodiment 1 or embodiment 2, and the vehicle USB power anti-backflow circuit 220 is connected between the power circuit 150 and the USB circuit 140 and connected to the external power supply device 160 through the USB circuit 140. In this embodiment, the vehicle system refers to the abbreviation of the vehicle infotainment product installed in the car, and the vehicle system can functionally realize information communication between people and cars, and cars and the outside world. The vehicle system can include all power modules on the vehicle, including motors, power batteries, electronic control systems, etc. In the present application, the trigger circuit 130 receives the signal of the working mode of the vehicle system 210, and outputs an electrical signal to the control circuit 120 according to the working signal, thereby controlling the switching circuit 110 to prevent power backflow. The USB power supply of the vehicle system 210 is prevented from backflowing to the external power supply. Whether in the power-on state or the power-off state, the switch circuit 110 can be effectively controlled to avoid a direct short circuit between the external power supply and the internal USB power supply of the vehicle system 210, which would cause voltage backflow when the host is shut down or restarted and damage components or external debugging equipment.

[0048] The implementation modes of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present application.

Claims

1. A vehicle-mounted USB power supply anti-backflow circuit, characterized in that: The circuit comprises: A switch circuit is provided with a first connection end, a second connection end, and a first enabling end, wherein the first connection end is connected to the power circuit, and the second connection end is connected to the power device through the USB circuit; A trigger circuit is connected to the vehicle computer system to obtain a working signal; And a control circuit, which is respectively connected to the first enabling end and the trigger circuit, is used to obtain a working signal of the trigger circuit and output an electrical signal to the control circuit according to the working signal, thereby controlling the on and off of the switch circuit to prevent power backflow.

2. The vehicle-mounted USB power supply anti-backflow circuit according to claim 1, characterized in that: The switch circuit comprises a first MOS transistor, a gate of the first MOS transistor being an enable terminal connected to the control circuit, a source being a second connection terminal connected to the USB circuit, and a drain being a first connection terminal connected to the power supply circuit.

3. The vehicle-mounted USB power supply anti-backflow circuit according to claim 2, characterized in that: The switch circuit further includes a first capacitor, one end of which is connected to the drain of the first MOS tube, and the other end of which is grounded.

4. The vehicle-mounted USB power supply anti-backflow circuit according to claim 2, characterized in that: The switch circuit further includes a first resistor, one end of which is connected to the source of the first MOS transistor, and the first resistor is connected to the gate of the first MOS transistor.

5. The vehicle-mounted USB power supply anti-backflow circuit according to claim 2, characterized in that: The control circuit includes a first voltage dividing circuit, a first enabling circuit, and a second voltage dividing circuit; The first enabling circuit is provided with a second enabling terminal, a third connecting terminal and a fourth connecting terminal. The second enabling terminal is connected to the trigger circuit through a first voltage dividing circuit, the third connecting terminal is connected to the first enabling terminal of the switch circuit through the second voltage dividing circuit, and the fourth connecting terminal is grounded.

6. The vehicle-mounted USB power supply anti-backflow circuit according to claim 5, characterized in that: The first enabling circuit is a MOS tube or a PNP transistor.

7. The vehicle-mounted USB power supply anti-backflow circuit according to claim 5, characterized in that: The first voltage divider circuit includes a second resistor and a third resistor connected to the second enable end, the other end of the second resistor is connected to the trigger circuit, and the other end of the third resistor is grounded.

8. The vehicle-mounted USB power supply anti-backflow circuit according to claim 5, characterized in that: The second voltage-dividing circuit includes a fourth resistor, one end of the fourth resistor is connected to the third connection end and the other end of the fourth resistor is connected to the gate of the first MOS tube.

9. The vehicle-mounted USB power supply anti-backflow circuit according to claim 1, characterized in that: The trigger circuit includes a control chip, which is provided with a detection end and a control end. The detection end is connected to the vehicle system, and the control end is connected to the control circuit; the control chip is used to obtain the working signal of the vehicle system and convert it into an electrical signal to control the control circuit.

10. A vehicle computer system, characterized in that: The invention comprises the vehicle-mounted USB power supply anti-backflow circuit, the power supply circuit and the USB circuit as described in any one of claims 1 to 9, wherein the vehicle-mounted USB power supply anti-backflow circuit is connected between the power supply circuit and the USB circuit and is connected to an external power supply device through the USB circuit.

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