Backflow prevention circuit and vehicle-mounted equipment

Abstract

The utility model discloses an anti-backflow circuit and a vehicle-mounted device. The anti-backflow circuit comprises a control module and an anti-backflow module. The input end of the control module is connected with a main control module of the vehicle-mounted equipment; the input end of the anti-backflow module is connected with the output end of the control module, and the output end of the anti-backflow module is connected with an external interface of the vehicle-mounted equipment. According to the utility model, voltage of external equipment can be prevented from flowing backward, and circuit damage is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle-mounted equipment, in particular to an anti-backflow circuit and a vehicle-mounted equipment. Background Art

[0002] The protection function of the traditional USB power interface is generally realized by the USB Charge chip, that is, the USB Charge chip has its own protection function, which usually includes overcurrent protection, overvoltage protection and overheating protection. The USB interface for vehicle applications is generally used as a connection port for mobile phones, U disks and computers to cooperate with functions such as mobile phone interconnection, U disk reading and burning upgrades. However, the power interface of mobile phones and computers generally has a voltage of about 5V. When it is connected to the vehicle-mounted equipment, if the vehicle-mounted equipment has not been started, it is possible that the voltage of the mobile phone and computer will be backflowed into the vehicle-mounted equipment, causing damage to the USB interface of the vehicle-mounted equipment. At present, the protection function of the USB Charge chip does not have an anti-backflow protection function. Utility Model Content

[0003] The utility model provides an anti-backflow circuit and a vehicle-mounted device, aiming to solve the problem that the USB interface of the current vehicle-mounted device does not have the anti-backflow function.

[0004] In the first aspect, the utility model provides an anti-backfeeding circuit, which includes a control module and an anti-backfeeding module; the input end of the control module is connected to the main control module of the vehicle-mounted device; the input end of the anti-backfeeding module is connected to the output end of the control module, and the output end of the anti-backfeeding module is connected to the external interface of the vehicle-mounted device.

[0005] Furthermore, the anti-backflow module includes a switch chip, one end of the switch chip is connected to the output end of the control module, and the other end of the switch chip is connected to the external interface.

[0006] Furthermore, the switch chip includes an enable pin, and the enable pin is connected to the control module.

[0007] Furthermore, the anti-backflow module also includes a first capacitor, one end of the first capacitor is connected to the control module, and the other end of the first capacitor is grounded.

[0008] Furthermore, the switch chip further comprises an input pin and an output pin, the input pin is connected to the output end of the control module, and the output pin is connected to the external interface.

[0009] Further, the anti-backflow module further includes a second capacitor and a third capacitor. One end of the second capacitor and the third capacitor is connected to the output pin of the switching chip, and the other end of the second capacitor and the third capacitor is grounded.

[0010] Further, a surge protection circuit is further included. One end of the surge protection circuit is connected to the output end of the anti-backflow module, and the other end of the surge protection circuit is grounded.

[0011] Further, the surge protection circuit includes a voltage suppressor. One end of the voltage suppressor is connected to the output end of the anti-backflow module, and the other end of the anti-backflow module is grounded.

[0012] Further, the voltage suppressor is a TVS tube. One end of the TVS tube is connected to the output end of the anti-backflow module, and the other end of the anti-backflow module is grounded.

[0013] In a second aspect, the present utility model further provides a vehicle-mounted device, which includes a main control module, an external interface, and the anti-backflow circuit described in any one of the above.

[0014] The vehicle-mounted device provided by the present utility model includes a main control module, an external interface, and an anti-backflow circuit. The anti-backflow circuit includes a control module and an anti-backflow module. The control module is connected to the main control module. The input end of the anti-backflow module is connected to the output end of the control module, and its output end is connected to the external interface. When devices such as mobile phones and computers are connected to the external interface, the anti-backflow module can prevent the voltage of devices such as mobile phones and computers from flowing back, avoiding damage to the interface of the vehicle-mounted device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the present utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It is a block diagram of the anti-backflow circuit provided by an embodiment of the present utility model;

[0017] Figure 2 It is a block diagram of the anti-backflow circuit provided by another embodiment of the present utility model;

[0018] Figure 3 It is a circuit diagram of the anti-backflow circuit provided by an embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] Next, the technical solutions in the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the present utility model. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0020] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0021] It should also be understood that the terms used in this specification of the present utility model are only for the purpose of describing specific embodiments and are not intended to limit the present utility model. As used in this specification of the present utility model and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms. It should be further understood that the term "and / or" used in this specification of the present utility model and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0022] See Figures 1 to 3 , Figure 1 is a block diagram of the anti-backflow circuit 100 provided by an embodiment of the present utility model; Figure 2 is a block diagram of the anti-backflow circuit 100 provided by another embodiment of the present utility model;

[0023] Figure 3 is a circuit diagram of the anti-backflow circuit 100 provided by an embodiment of the present utility model. As Figure 1 shown, the anti-backflow circuit 100 provided by the present utility model includes a control module 10 and an anti-backflow module 20; the input end of the control module 10 is connected to the main control module 200 of the vehicle-mounted device; the input end of the anti-backflow module 20 is connected to the output end of the control module 10, and the output end of the anti-backflow module 20 is connected to the external interface 300 of the vehicle-mounted device.

[0024] Specifically, the vehicle-mounted device may include a main control module 200, an external interface 300, and an anti-backflow circuit 100. The main control module 200 may include an MCU, and the MCU is used to control the vehicle-mounted device to implement various functions. The external interface 300 is used to connect to external devices, and the external devices may be devices such as mobile phones, computers, and USB flash drives. The anti-backflow circuit 100 is disposed between the main control module 200 and the external interface 300.

[0025] The anti-backflow circuit 100 may include a control module 10 and an anti-backflow module 20. The control module 10 may include a control chip, which may be a USB Charge chip. The input end of the control module 10 is connected to the main control module 200, and the output end of the control module 10 is connected to the input end of the anti-backflow module 20. The output end of the anti-backflow module 20 is connected to the external interface 300 to prevent the voltage of the external device from backflowing to the vehicle-mounted device and causing damage to the chip of the vehicle-mounted device.

[0026] As a further embodiment, the anti-backflow module 20 includes a switch chip U1 , one end of the switch chip U1 is connected to the output end of the control module 10 , and the other end of the switch chip U1 is connected to the external interface 300 .

[0027] Among them, the anti-backflow module 20 may include a switch chip U1, the switch chip U1 may include multiple pins, one of the multiple pins is used to connect to the output end of the control module 10, and another pin of the multiple pins is used to connect to the external interface 300. The voltage of the external device can be prevented from backflowing into the vehicle-mounted device by turning on and off the switch chip U1.

[0028] When in use, the control module 10 can control the on and off of the switch chip U1 through a control signal. When the switch chip U1 is disconnected, even if an external device is connected to the external interface 300, since the switch chip U1 is in the off state, the voltage of the external device will not enter the interior of the vehicle-mounted device, thereby avoiding damage to the vehicle-mounted device.

[0029] See also Figure 3 As a further embodiment, the switch chip U1 includes an enable pin EN, and the enable pin EN is connected to the control module 10 .

[0030] Among the multiple pins included in the switch chip U1, an enable pin EN is included, and the enable pin EN is connected to the control module 10 and is used to receive a control signal from the control module 10. When the enable pin EN of the switch chip U1 does not receive a control signal, the switch chip U1 is disconnected, and when the enable pin EN of the switch chip U1 receives a control signal from the control module 10, the switch chip U1 is turned on.

[0031] Specifically, the control signal may be a PGOOD signal, which is used to indicate that the power output is stable. When the enable pin EN of the switch chip U1 receives the PGOOD signal, the switch chip U1 is turned on. At this time, the power supply of the vehicle-mounted device is stable, and the voltage of the external device cannot flow back into the vehicle-mounted device.

[0032] As a further embodiment, the anti-backflow module 20 further includes a first capacitor C1. One end of the first capacitor C1 is connected to the control module 10, and the other end of the first capacitor C1 is grounded.

[0033] Among them, the first capacitor C1 is connected between the control module 10 and the switch chip U1. Specifically, the first capacitor C1 is connected between the enable pin EN and the control module 10 for protecting the enable pin EN.

[0034] As a further embodiment, the switch chip U1 further includes an input pin IN and an output pin OUT. The input pin IN is connected to the output end of the control module 10, and the output pin OUT is connected to the external interface 300.

[0035] Among them, the input pin IN of the switch chip U1 is connected to the control module 10, and its output pin OUT is connected to the external interface 300. When the switch chip U1 is turned on, the output signal of the control module 10 can enter the external interface 300 through the switch chip U1.

[0036] As a further embodiment, the anti-backflow module 20 further includes a second capacitor C2 and a third capacitor C3. One end of the second capacitor C2 and the third capacitor C3 is connected to the output pin OUT of the switch chip U1, and the other end of the second capacitor C2 and the third capacitor C3 is grounded.

[0037] Among them, the second capacitor C2 and the third capacitor C3 are both connected between the switch chip U1 and the external interface 300 for protecting the output pin OUT.

[0038] See Figure 2 and Figure 3 As a further embodiment, it further includes a surge protection circuit 30. One end of the surge protection circuit 30 is connected to the output end of the anti-backflow module 20, and the other end of the surge protection circuit 30 is grounded. As a further embodiment, the surge protection circuit 30 includes a voltage suppressor TVS. One end of the voltage suppressor TVS is connected to the output end of the anti-backflow module 20, and the other end of the anti-backflow module 20 is grounded. As a further embodiment, the voltage suppressor TVS is a TVS tube. One end of the TVS tube is connected to the output end of the anti-backflow module 20, and the other end of the anti-backflow module 20 is grounded.

[0039] Among them, the surge protection circuit 30 may include a voltage suppressor TVS. The voltage suppressor TVS may specifically be a TVS tube for monitoring and limiting the overvoltage in the circuit and controlling it within a set safety range to prevent excessive voltage from damaging the devices in the circuit.

[0040] The present utility model further provides a vehicle-mounted device, which includes a main control module 200, an external interface 300, and the anti-backflow circuit 100 according to any one of the above embodiments; the anti-backflow circuit 100 includes a control module 10 and an anti-backflow module 20; the input end of the control module 10 is connected to the main control module 200 of the vehicle-mounted device; the input end of the anti-backflow module 20 is connected to the output end of the control module 10, and the output end of the anti-backflow module 20 is connected to the external interface 300 of the vehicle-mounted device.

[0041] Specifically, the vehicle-mounted device may include a main control module 200, an external interface 300, and an anti-backflow circuit 100. The main control module 200 may include an MCU, which is used to control the vehicle-mounted device to implement various functions. The external interface 300 is used to connect to external devices, and the external devices may be devices such as mobile phones, computers, and USB flash drives. The anti-backflow circuit 100 is disposed between the main control module 200 and the external interface 300.

[0042] The anti-backflow circuit 100 may include a control module 10 and an anti-backflow module 20. The control module 10 may include a control chip, and the control chip may be a USB Charge chip. The input end of the control module 10 is connected to the main control module 200, and the output end of the control module 10 is connected to the input end of the anti-backflow module 20. The output end of the anti-backflow module 20 is connected to the external interface 300, and is used to prevent the voltage of the external device from flowing back to the vehicle-mounted device and damaging the chips of the vehicle-mounted device.

[0043] The anti-backflow circuit and the vehicle-mounted device of the present utility model can prevent the voltage of the external device from flowing back, thereby avoiding damage to the vehicle-mounted device.

[0044] The above is only the specific implementation manner of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope of the claims.

Claims

1. A backfeed prevention circuit, characterized in that: Applied to vehicle-mounted equipment, the anti-backflow circuit includes: A control module, an input end of which is connected to a main control module of the vehicle-mounted device; An anti-backflow module, wherein the input end of the anti-backflow module is connected to the output end of the control module, and the output end of the anti-backflow module is connected to the external interface of the vehicle-mounted device.

2. The anti-backflow circuit according to claim 1, characterized in that: The anti-backflow module includes a switch chip, one end of the switch chip is connected to the output end of the control module, and the other end of the switch chip is connected to the external interface.

3. The anti-backflow circuit according to claim 2, characterized in that: The switch chip includes an enable pin, and the enable pin is connected to the control module.

4. The anti-backflow circuit according to claim 3, characterized in that: The anti-backflow module further includes a first capacitor, one end of which is connected to the control module, and the other end of which is grounded.

5. The anti-backflow circuit according to claim 3, characterized in that: The switch chip further comprises an input pin and an output pin, wherein the input pin is connected to the output end of the control module, and the output pin is connected to the external interface.

6. The anti-backflow circuit according to claim 5, characterized in that: The anti-backflow module further includes a second capacitor and a third capacitor, one end of the second capacitor and the third capacitor is connected to the output pin of the switch chip, and the other end of the second capacitor and the third capacitor is grounded.

7. The anti-backflow circuit according to claim 1, characterized in that: It also includes a surge protection circuit, one end of which is connected to the output end of the anti-backflow module, and the other end of which is grounded.

8. The anti-backflow circuit according to claim 7, characterized in that: The surge protection circuit comprises a voltage suppressor, one end of the voltage suppressor is connected to the output end of the anti-backfeed module, and the other end of the anti-backfeed module is grounded.

9. The anti-backflow circuit according to claim 8, characterized in that: The voltage suppressor is a TVS tube, one end of the TVS tube is connected to the output end of the anti-backflow module, and the other end of the anti-backflow module is grounded.

10. A vehicle-mounted device, characterized in that: It comprises a main control module, an external interface and an anti-backflow circuit as claimed in any one of claims 1 to 9.

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