CN220639750U - Circuit for automatic switching power supply of automobile data recorder - Google Patents

Abstract

The utility model relates to the technical field of electrician electronics, in particular to a circuit for automatically switching power supply of a vehicle recorder, which comprises: the self-locking circuit and the switching circuit; the first end of the self-locking circuit is connected with the first external power interface, and the second end of the self-locking circuit is connected with the first end of the switching circuit; the second end of the switching circuit is connected with the first external power interface, the third end of the switching circuit is connected with the second external power interface, and the fourth end of the switching circuit is connected with the automobile data recorder; when the self-locking circuit is used for supplying power to the safe box, a high-level signal is continuously output to the switching circuit, so that the switching circuit conducts a power supply loop between the safe box and the automobile data recorder. Correspondingly, if the switching circuit does not receive the high-level signal, a power supply loop between the cigar lighter and the automobile data recorder is conducted. The automobile data recorder power supply system realizes automatic switching of power supply of the automobile data recorder, and solves the technical problem that the existing automobile data recorder is complex to set during installation.

Description

Circuit for automatic switching power supply of automobile data recorder

Technical Field

The utility model relates to the technical field of electrician electronics, in particular to a circuit for automatically switching power supply of a vehicle recorder.

Background

When the automobile data recorder is installed, two power taking interfaces are arranged in the automobile, and a power supply fuse box and a vehicle-mounted cigar lighter of the automobile are arranged. The safe box can be provided with three interfaces of ground, B+ and ACC, wherein B+ is 12V which is commonly supplied, the ACC signal is high when the automobile fires, and the ACC signal is low when the automobile fires. The safe box can still be powered through B+ after the automobile is flamed out, and a recorder connected to the safe box is powered through B+ and controls the on-off state or enters into an out-of-sleep state through an ACC signal. The vehicle-mounted cigar lighter has only two interfaces, a ground signal and VCC, the VCC output is high when the vehicle-mounted cigar lighter is ignited, and the VCC does not output when the vehicle-mounted cigar lighter is flameout. The recorder connected to the cigar lighter is not powered under flameout, and needs to be powered by a battery, and the VCC signal is not only a power supply, but also a flameout and sparking signal. When the vehicle-mounted recorder product is installed, two modes of installation from a safe box and installation from a cigar lighter are often required to be compatible. The interface to the recorder is a USB interface, whether it be a safe or a cigar lighter

When a usb interface line on the market is connected with a fuse box, a B+ signal is usually connected to 1pin, an ACC signal is connected to 4pin, and the ground is connected to 5 pin. When the cigar lighter is connected, VCC is connected to 1pin,4pin is empty, and ground is connected to 5 pin. The recorder is compatible with both types of wiring, so that the two modes need to be identified, and when a fuse box is used, 4 pins need to be used as signals for striking sparks. When using a cigar lighter, 1pin is required as the ignition and extinction signal. The current solutions in the market are to let the user himself set up on the device whether to use the mode of the fuse box installation or the mode of the cigar lighter installation after the recording is completed. However, it is difficult for many users to distinguish between specific installation configurations of the cartridge installation or the cigar lighter installation, and incorrect configurations may result in abnormal use.

The foregoing is provided merely for the purpose of facilitating understanding of the technical solutions of the present utility model and is not intended to represent an admission that the foregoing is prior art.

Disclosure of Invention

The utility model mainly aims to provide a circuit for automatically switching power supply of a vehicle recorder, and aims to solve the technical problem of complex arrangement during installation of the existing vehicle recorder.

In order to achieve the above object, the present utility model provides a circuit for automatically switching power supply of a vehicle recorder, the circuit for automatically switching power supply of a vehicle recorder includes:

the self-locking circuit and the switching circuit;

the first end of the self-locking circuit is connected with a first external power interface, and the second end of the self-locking circuit is connected with the first end of the switching circuit; the second end of the switching circuit is connected with the first external power interface, the third end of the switching circuit is connected with the second external power interface, and the fourth end of the switching circuit is connected with the automobile data recorder;

the self-locking circuit is used for continuously outputting a high-level signal to the switching circuit when the first external power interface outputs a high-level voltage;

the switching circuit is used for conducting a power supply loop between the first external power interface and the automobile data recorder when the high-level signal is received; and when the first end is at a low level, a power supply loop between the second external power interface and the automobile data recorder is conducted.

Optionally, the self-locking circuit includes:

an OR gate circuit and a feedback circuit;

the first input end of the OR gate circuit is connected with a first external power interface, the second input end of the OR gate circuit is connected with the first end of the feedback circuit, and the output end of the OR gate circuit is connected with the first end of the switching circuit; the second end of the feedback circuit is connected with the output end of the OR gate circuit;

the OR gate circuit is used for outputting a high level through the output terminal when the first input terminal or the second input terminal has the high level;

and the feedback circuit is used for outputting high level to the second input end of the OR gate when the output end of the OR gate outputs high level.

Optionally, the self-locking circuit further comprises:

a second resistor;

one end of the second resistor is connected with the first input end of the OR gate circuit, and the other end of the second resistor is grounded.

Optionally, the self-locking circuit further comprises:

a second capacitor;

one end of the second capacitor is connected with the power input end of the OR gate circuit, and the other end of the second capacitor is grounded; the power input end of the OR gate circuit is connected with an external power interface, and the grounding end of the OR gate circuit is grounded.

Optionally, the feedback circuit includes:

a first resistor and a first capacitor;

one end of the first resistor is connected with the output end of the OR gate circuit, and the other end of the first resistor is connected with the second input end of the OR gate circuit; one end of the first capacitor is connected with the second input end of the OR gate circuit, and the other end of the first capacitor is grounded.

Optionally, the or circuit includes:

a first diode, a second diode and a photocoupler;

the anode of the first diode is connected with a first external power interface, and the cathode of the first diode is connected with the first end of the photoelectric coupler; the anode of the second diode is connected with the first end of the feedback circuit, and the cathode of the second diode is connected with the second end of the photoelectric coupler; and the third end of the photoelectric coupler is connected with the first end of the switching circuit, and the fourth end of the photoelectric coupler is grounded.

Optionally, the or circuit further includes:

a voltage dividing circuit;

the first end of the voltage dividing circuit is connected with an external power interface, and the second end of the voltage dividing circuit is connected with the third end of the photoelectric coupler;

the voltage dividing circuit is used for dividing the power supply voltage output by the external power supply interface and transmitting the divided power supply voltage to the third end of the photoelectric coupler.

Optionally, the switching circuit includes:

the switch chip, the third resistor and the fourth resistor;

the control end of the switch chip is connected with the second end of the self-locking circuit, the first input end of the switch chip is connected with the first external power interface, the second input end of the switch chip is connected with the second external power interface, and the output end of the switch chip is connected with the automobile data recorder; one end of the third resistor is connected with the control end of the switch chip, and the other end of the third resistor is grounded; one end of the fourth resistor is connected with the first input end of the switch chip, and the other end of the fourth resistor is grounded.

Optionally, the switching circuit further includes:

a power supply circuit;

the first end of the power supply circuit is connected with the power input end of the switch chip, and the second end of the power supply circuit is connected with the grounding end of the switch chip;

the power supply circuit is used for providing driving voltage for the switch chip.

Optionally, the power supply circuit includes:

a third capacitor;

one end of the third capacitor is connected with an external power interface and the power input end of the switch chip, and the other end of the third capacitor is connected with the grounding end of the switch chip and grounded.

The circuit for automatically switching power supply of the automobile data recorder provided by the utility model comprises the following components: the self-locking circuit and the switching circuit; the first end of the self-locking circuit is connected with a first external power interface, and the second end of the self-locking circuit is connected with the first end of the switching circuit; the second end of the switching circuit is connected with the first external power interface, the third end of the switching circuit is connected with the second external power interface, and the fourth end of the switching circuit is connected with the automobile data recorder; the self-locking circuit is used for continuously outputting a high-level signal to the switching circuit when the first external power interface outputs a high-level voltage; the switching circuit is used for conducting a power supply loop between the first external power interface and the automobile data recorder when the high-level signal is received; and when the first end is at a low level, a power supply loop between the second external power interface and the automobile data recorder is conducted. According to the utility model, the self-locking circuit is utilized, when the fuse box is connected to supply power, a high-level signal is continuously output to the switching circuit, so that the switching circuit conducts a power supply loop between the fuse box and the automobile data recorder. Correspondingly, if the switching circuit does not receive the high-level signal, a power supply loop between the cigar lighter and the automobile data recorder is conducted. The automobile data recorder power supply system realizes automatic switching of power supply of the automobile data recorder, and solves the technical problem that the existing automobile data recorder is complex to set during installation.

Drawings

FIG. 1 is a functional block diagram of a first embodiment of an auto-switching power supply circuit for a vehicle event data recorder according to the present utility model;

fig. 2 is a first schematic circuit diagram of a first embodiment of a circuit for automatically switching power supply of a vehicle event data recorder according to the present utility model;

fig. 3 is a second circuit schematic diagram of the first embodiment of the circuit for automatically switching power supply of the automobile data recorder according to the present utility model;

fig. 4 is a first circuit schematic diagram of a second embodiment of a circuit for automatically switching power supply of a vehicle event data recorder according to the present utility model.

Reference numerals	Name of the name	Reference numerals	Name of the name
				100	Self-locking circuit	200	Switching circuit
R2	Second resistor	C2	Second capacitor
				R1	First resistor	C1	First capacitor
D1	First diode	D2	Second diode
				OC	Photoelectric coupler	U1	Switch chip
R3	Third resistor	R4	Fourth resistor
				C3	Third capacitor

The achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

Referring to fig. 1, fig. 1 is a functional block diagram of a first embodiment of a circuit for automatically switching power supply of a vehicle recorder according to the present utility model.

As shown in fig. 1, the circuit for automatically switching power supply of the automobile data recorder in this embodiment includes: a self-locking circuit 100 and a switching circuit 200; a first end of the self-locking circuit 100 is connected with a first external power interface, and a second end of the self-locking circuit 100 is connected with a first end of the switching circuit 200; the second end of the switching circuit 200 is connected with the first external power interface, the third end of the switching circuit 200 is connected with the second external power interface, and the fourth end of the switching circuit 200 is connected with the automobile data recorder.

The self-locking circuit 100 is configured to continuously output a high-level signal to the switching circuit 200 when the first external power interface outputs a high-level voltage.

It will be appreciated that the self-locking circuit may be an electronic circuit design for controlling the switching state of the circuit and maintaining it stable for a certain period of time. It typically comprises a trigger and a feedback loop. When the input signal meets certain conditions, the flip-flop will switch its output state. This output state will be returned to the input of the flip-flop by a feedback loop, keeping the flip-flop in the switched state until other conditions are met.

In a specific implementation, the self-locking circuit may be composed of one bistable flip-flop and several logic gates. When the first external power interface outputs a high level, the output of the bistable flip-flop remains high. And after the logic gate receives the high-level signal, continuously outputting the high-level signal.

The switching circuit 200 is configured to, when receiving the high-level signal, turn on a power supply loop between the first external power interface and the automobile data recorder; and when the first end is at a low level, a power supply loop between the second external power interface and the automobile data recorder is conducted.

It should be noted that the switching circuit generally includes one or more switching elements, such as transistors, relays, or field effect transistors. The switching elements control the connection or disconnection of the circuit according to the variation of the input signal.

In a specific implementation, the switching circuit may be composed of two relays and several switches. When a high-level signal is received, the relay 1 is closed, and a power supply loop between the first external power interface and the automobile data recorder is conducted. When the first end is at a low level, the relay 2 is closed, and a power supply loop between the second external power interface and the automobile data recorder is conducted.

The circuit for automatically switching power supply of the automobile data recorder provided by the embodiment comprises: the self-locking circuit and the switching circuit; the first end of the self-locking circuit is connected with a first external power interface, and the second end of the self-locking circuit is connected with the first end of the switching circuit; the second end of the switching circuit is connected with the first external power interface, the third end of the switching circuit is connected with the second external power interface, and the fourth end of the switching circuit is connected with the automobile data recorder; the self-locking circuit is used for continuously outputting a high-level signal to the switching circuit when the first external power interface outputs a high-level voltage; the switching circuit is used for conducting a power supply loop between the first external power interface and the automobile data recorder when the high-level signal is received; and when the first end is at a low level, a power supply loop between the second external power interface and the automobile data recorder is conducted. According to the utility model, the self-locking circuit is utilized, when the fuse box is connected to supply power, a high-level signal is continuously output to the switching circuit, so that the switching circuit conducts a power supply loop between the fuse box and the automobile data recorder. Correspondingly, if the switching circuit does not receive the high-level signal, a power supply loop between the cigar lighter and the automobile data recorder is conducted. The automobile data recorder power supply system realizes automatic switching of power supply of the automobile data recorder, and solves the technical problem that the existing automobile data recorder is complex to set during installation.

Further, in this embodiment, the self-locking circuit includes: an OR gate circuit and a feedback circuit; the first input end of the OR gate circuit is connected with a first external power interface, the second input end of the OR gate circuit is connected with the first end of the feedback circuit, and the output end of the OR gate circuit is connected with the first end of the switching circuit; and the second end of the feedback circuit is connected with the output end of the OR gate circuit.

The OR gate circuit is used for outputting a high level through the output terminal when the first input terminal or the second input terminal is high.

It will be appreciated that the or circuit may be a basic logic gate for implementing an or operation in boolean logic. It has two or more input signals and one output signal. When any one or more of the input signals is high (logic 1), the output signal will be high. The output signal is low only when all input signals are low (logic 0). OR gates are typically composed of transistors, diodes, or field effect transistors. The method can be used in a combination logic circuit and a digital circuit to realize the functions of logic operation, signal selection, data transmission, signal processing and the like.

And the feedback circuit is used for outputting high level to the second input end of the OR gate when the output end of the OR gate outputs high level.

It should be noted that the feedback circuit may be an electronic circuit design in which a portion of the output signal is reintroduced into the input of the circuit to affect the behavior of the circuit. The self-regulation and stability of the circuit are realized by connecting the output signal with the input signal.

In a specific implementation, the feedback circuit may be composed of a comparator and a delay. The input end of the comparator is connected with the output end of the OR gate circuit, and the output end of the comparator is connected with the input end of the delay. When the output end of the OR gate circuit outputs a high level, the comparator outputs a high level signal to the delayer, and the delayer outputs a high level signal to the second input end of the OR gate circuit.

In the foregoing manner of the present embodiment, the self-locking circuit includes: an OR gate circuit and a feedback circuit; the first input end of the OR gate circuit is connected with a first external power interface, the second input end of the OR gate circuit is connected with the first end of the feedback circuit, and the output end of the OR gate circuit is connected with the first end of the switching circuit; the second end of the feedback circuit is connected with the output end of the OR gate circuit; the OR gate circuit is used for outputting a high level through the output terminal when the first input terminal or the second input terminal has the high level; and the feedback circuit is used for outputting high level to the second input end of the OR gate when the output end of the OR gate outputs high level. When the first external power interface outputs high level, the self-locking circuit continuously outputs high level signals, and stable power supply of the automobile data recorder is ensured.

Further, referring to fig. 2, fig. 2 is a first circuit schematic diagram of a first embodiment of a circuit for automatically switching power supply of a vehicle event data recorder according to the present utility model, in this embodiment, the self-locking circuit further includes:

a second resistor R2; one end of the second resistor R2 is connected with the first input end of the OR gate circuit, and the other end of the second resistor R2 is grounded.

In the above manner of this embodiment, the second resistor is connected between the first input terminal of the or circuit and the ground, and is used to limit the input current of the or circuit. When the first external power interface outputs high level, the self-locking circuit continuously outputs high level signals, stable power supply of the automobile data recorder is ensured, input current is limited through the second resistor, and stability and safety of the circuit are ensured.

Further, in this embodiment, the self-locking circuit further includes:

a second capacitor C2; one end of the second capacitor C2 is connected with the power input end of the OR gate circuit, and the other end of the second capacitor C is grounded; the power input end of the OR gate circuit is connected with an external power interface, and the grounding end of the OR gate circuit is grounded.

Further, in this embodiment, the feedback circuit includes: a first resistor R1 and a first capacitor C1; one end of the first resistor R1 is connected with the output end of the OR gate circuit, and the other end of the first resistor R1 is connected with the second input end of the OR gate circuit; one end of the first capacitor C1 is connected with the second input end of the OR gate circuit, and the other end of the first capacitor C is grounded.

In the implementation process, when the cigar lighter is accessed, the 4pin, namely the first external power interface, is always in a low level, so that the output is always in a low level. When the fuse box is accessed and ignited, 4pin becomes high, and the output level is high through the or gate. While the output signal is fed back to the other input of the or gate. This way the output level is always high regardless of whether the car is flameout or on fire, i.e. whether 4pin is high or low. Therefore, the cigar lighter is accessed, the output level is low, the fuse box is accessed, and the output level is high.

Further, referring to fig. 3, fig. 3 is a second circuit schematic diagram of a first embodiment of a circuit for automatically switching power supply of a vehicle event data recorder according to the present utility model, in this embodiment, the or circuit includes:

a first diode D1, a second diode D2, and a photo coupler OC; the anode of the first diode D1 is connected with a first external power interface, and the cathode of the first diode D1 is connected with the first end of the photoelectric coupler OC; the anode of the second diode D2 is connected with the first end of the feedback circuit, and the cathode of the second diode D2 is connected with the second end of the photoelectric coupler OC; the third end of the photoelectric coupler OC is connected with the first end of the switching circuit, and the fourth end of the photoelectric coupler OC is grounded.

Further, in this embodiment, the or circuit further includes:

a voltage dividing circuit; the first end of the voltage dividing circuit is connected with an external power interface, and the second end of the voltage dividing circuit is connected with the third end of the photoelectric coupler OC.

The voltage dividing circuit is configured to divide a power supply voltage output by the external power supply interface, and transmit the divided power supply voltage to the third terminal of the optocoupler OC.

It will be appreciated that the voltage divider circuit may be an electronic circuit design for scaling down the voltage signal. It is typically composed of resistors that divide the input voltage into lower output voltages. The voltage divider circuit can be used for adjusting the voltage level in the circuit to adapt to different application requirements. It can be used to reduce the amplitude of the voltage signal, converting the high voltage signal into a signal suitable for processing by the low voltage circuit.

In a specific implementation, the voltage divider circuit may be composed of two resistors. The first terminal is connected to an external power interface and the second terminal is connected to a third terminal of the optocoupler OC. The voltage dividing circuit divides the power supply voltage output by the external power supply interface through a proper resistance proportion so as to adapt to the input voltage requirement of the photoelectric coupler OC.

In the above manner of this embodiment, the first end of the voltage dividing circuit is connected to the external power interface, and the second end is connected to the third end of the optocoupler OC. The voltage dividing circuit is used for dividing the power supply voltage output by the external power supply interface and transmitting the divided power supply voltage to the third end of the photoelectric coupler OC. The voltage of the external power interface is properly divided by the voltage dividing circuit so as to meet the input voltage requirement of the photoelectric coupler.

Further, based on the above embodiment, a second embodiment of the present application is provided, and referring to fig. 4, fig. 4 is a schematic diagram of a first circuit of a second embodiment of a circuit for automatically switching power supply of a vehicle event data recorder according to the present utility model. The switching circuit in this embodiment includes:

a switch chip U1, a third resistor R3 and a fourth resistor R4; the control end of the switch chip U1 is connected with the second end of the self-locking circuit, the first input end of the switch chip U1 is connected with the first external power interface, the second input end of the switch chip U1 is connected with the second external power interface, and the output end of the switch chip U1 is connected with the automobile data recorder; one end of the third resistor R3 is connected with the control end of the switch chip U1, and the other end of the third resistor R is grounded; one end of the fourth resistor R4 is connected with the first input end of the switch chip U1, and the other end of the fourth resistor R is grounded.

It will be appreciated that the switching chip may be an Integrated Circuit (IC) for controlling switching operations in the circuit. It typically contains a plurality of switching channels that can open or close the connection of the circuit depending on the control of the input signal. The operating principle of the switch chip is based on the control of switching elements such as transistors or field effect transistors. When the input signal meets a specific condition, the switch chip will switch the state of its channel to connect or disconnect it.

In the above manner of the present embodiment, the switching circuit includes: the switch chip, the third resistor and the fourth resistor; the control end of the switch chip is connected with the second end of the self-locking circuit, the first input end of the switch chip is connected with the first external power interface, the second input end of the switch chip is connected with the second external power interface, and the output end of the switch chip is connected with the automobile data recorder; one end of the third resistor is connected with the control end of the switch chip, and the other end of the third resistor is grounded; one end of the fourth resistor is connected with the first input end of the switch chip, and the other end of the fourth resistor is grounded. The function of the switching circuit is realized, the switching of the power supply loop is realized through the control of the switching chip and the control circuit, and the stable power supply of the automobile data recorder under different power supply states is ensured.

Further, in this embodiment, the switching circuit further includes: a power supply circuit; the first end of the power supply circuit is connected with the power input end of the switch chip, and the second end of the power supply circuit is connected with the grounding end of the switch chip.

The power supply circuit is used for providing driving voltage for the switch chip.

It is understood that the power supply circuit may refer to a circuit design for providing power to electronic devices and circuits. It includes a power supply and associated electronics for converting electrical energy to voltages, currents and frequencies required for proper operation of the device.

In a specific implementation, the first terminal of the power supply circuit is connected to the power input terminal of the switch chip, and the second terminal is connected to the ground terminal of the switch chip. The power supply circuit may be a voltage stabilizing circuit or a power module, and is capable of providing a stable driving voltage to the switch chip.

In the above manner of the present embodiment, by using the power supply circuit; the first end of the power supply circuit is connected with the power input end of the switch chip, and the second end of the power supply circuit is connected with the grounding end of the switch chip; the power supply circuit is used for providing driving voltage for the switch chip. The driving voltage is provided for the switch chip through the power supply circuit, so that stable power supply of the automobile data recorder is ensured.

Further, in this embodiment, the power supply circuit includes:

a third capacitor C3; one end of the third capacitor C3 is connected with an external power interface and the power input end of the switch chip, and the other end of the third capacitor C is connected with the grounding end of the switch chip and grounded.

In this embodiment, when the cigar lighter is accessed, the output level of the self-locking circuit is low, so that the 1pin signal is output to the automobile data recorder. When the safe box is accessed, the output level of the self-locking circuit is high, so that a 4pin signal is output to the automobile data recorder for output.

Therefore, no matter which power-on mode is adopted, only the output signal of the automobile data recorder is judged as the ignition and flameout signal on software, and the on-off and dormancy awakening of the automobile data recorder are controlled. That is, the difference of the control signals caused by the power-on mode is transparent to the software after the conversion of the circuit. The purpose of compatible installation of the safe box and the cigar lighter without additional configuration of a user is achieved.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or system that comprises the element.

The foregoing embodiment numbers of the present utility model are merely for the purpose of description, and do not represent the advantages or disadvantages of the embodiments.

The foregoing description is only of the preferred embodiments of the present utility model, and is not intended to limit the scope of the utility model, but rather is intended to cover any equivalents of the structures or equivalent processes disclosed herein or in the alternative, which may be employed directly or indirectly in other related arts.

Although the present utility model is disclosed above, the present utility model is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the utility model, and the scope of the utility model should be assessed accordingly to that of the appended claims.

Claims (10)

1. The utility model provides a circuit of vehicle event data recorder automatic switch power supply which characterized in that, vehicle event data recorder automatic switch power supply's circuit includes:

the self-locking circuit and the switching circuit;

the first end of the self-locking circuit is connected with a first external power interface, and the second end of the self-locking circuit is connected with the first end of the switching circuit; the second end of the switching circuit is connected with the first external power interface, the third end of the switching circuit is connected with the second external power interface, and the fourth end of the switching circuit is connected with the automobile data recorder;

the self-locking circuit is used for continuously outputting a high-level signal to the switching circuit when the first external power interface outputs a high-level voltage;

the switching circuit is used for conducting a power supply loop between the first external power interface and the automobile data recorder when the high-level signal is received; and when the first end is at a low level, a power supply loop between the second external power interface and the automobile data recorder is conducted.

2. The circuit for automatically switching power supply of a vehicle event data recorder of claim 1, wherein the self-locking circuit comprises:

an OR gate circuit and a feedback circuit;

the first input end of the OR gate circuit is connected with a first external power interface, the second input end of the OR gate circuit is connected with the first end of the feedback circuit, and the output end of the OR gate circuit is connected with the first end of the switching circuit; the second end of the feedback circuit is connected with the output end of the OR gate circuit;

the OR gate circuit is used for outputting a high level through the output terminal when the first input terminal or the second input terminal has the high level;

and the feedback circuit is used for outputting high level to the second input end of the OR gate when the output end of the OR gate outputs high level.

3. The circuit for automatically switching power supply of a vehicle event data recorder of claim 2, wherein the self-locking circuit further comprises:

a second resistor;

one end of the second resistor is connected with the first input end of the OR gate circuit, and the other end of the second resistor is grounded.

4. The circuit for automatically switching power supply of a vehicle event data recorder of claim 2, wherein the self-locking circuit further comprises:

a second capacitor;

one end of the second capacitor is connected with the power input end of the OR gate circuit, and the other end of the second capacitor is grounded; the power input end of the OR gate circuit is connected with an external power interface, and the grounding end of the OR gate circuit is grounded.

5. The circuit for automatically switching power supply of a vehicle event recorder according to claim 2, wherein the feedback circuit comprises:

a first resistor and a first capacitor;

one end of the first resistor is connected with the output end of the OR gate circuit, and the other end of the first resistor is connected with the second input end of the OR gate circuit; one end of the first capacitor is connected with the second input end of the OR gate circuit, and the other end of the first capacitor is grounded.

6. The circuit for automatically switching power supply of a vehicle event data recorder according to claim 2, wherein the or circuit comprises:

a first diode, a second diode and a photocoupler;

the anode of the first diode is connected with a first external power interface, and the cathode of the first diode is connected with the first end of the photoelectric coupler; the anode of the second diode is connected with the first end of the feedback circuit, and the cathode of the second diode is connected with the second end of the photoelectric coupler; and the third end of the photoelectric coupler is connected with the first end of the switching circuit, and the fourth end of the photoelectric coupler is grounded.

7. The circuit for automatically switching power supply of a vehicle event data recorder of claim 6, wherein the or circuit further comprises:

a voltage dividing circuit;

the first end of the voltage dividing circuit is connected with an external power interface, and the second end of the voltage dividing circuit is connected with the third end of the photoelectric coupler;

the voltage dividing circuit is used for dividing the power supply voltage output by the external power supply interface and transmitting the divided power supply voltage to the third end of the photoelectric coupler.

8. The circuit for automatically switching power supply of a vehicle event recorder according to claim 1, wherein the switching circuit comprises:

the switch chip, the third resistor and the fourth resistor;

the control end of the switch chip is connected with the second end of the self-locking circuit, the first input end of the switch chip is connected with the first external power interface, the second input end of the switch chip is connected with the second external power interface, and the output end of the switch chip is connected with the automobile data recorder; one end of the third resistor is connected with the control end of the switch chip, and the other end of the third resistor is grounded; one end of the fourth resistor is connected with the first input end of the switch chip, and the other end of the fourth resistor is grounded.

9. The automobile data recorder auto-switching circuit of claim 8, wherein the switching circuit further comprises:

a power supply circuit;

the first end of the power supply circuit is connected with the power input end of the switch chip, and the second end of the power supply circuit is connected with the grounding end of the switch chip;

the power supply circuit is used for providing driving voltage for the switch chip.

10. The automobile data recorder auto-switching power supply circuit of claim 9, wherein the power supply circuit comprises:

a third capacitor;

one end of the third capacitor is connected with an external power interface and the power input end of the switch chip, and the other end of the third capacitor is connected with the grounding end of the switch chip and grounded.