阅读说明：本技术 一种车辆灯光控制电路 (Vehicle light control circuit ) 是由 黄明生 周庆生 徐辉 齐伟华 鲍文光 于 2021-09-27 设计创作，主要内容包括：本发明公开了一种车辆灯光控制电路,包括中央处理器、开关电路、检测电路及开关,中央处理器通过检测电路检测开关的状态,在开关的第一端与第二端连接或者开关的第一端与第三端连接时,表示用户需要使左转向灯或右转向灯点亮,此时,使开关电路的输入端和输出端导通,以为左转向灯或者右转向灯供电。可见,本申请中,在用户控制开关的第一端既不与自身的第二端连接,也不与自身的第三端连接时,开关电路为截止的状态,开关的第一端不会带电,从而避免将电源通过开关泄漏至人体,避免对人体造成危害,也可以避免电火花等现象的产生,从而降低车辆灯光控制电路的风险。(The invention discloses a vehicle light control circuit, which comprises a central processing unit, a switch circuit, a detection circuit and a switch, wherein the central processing unit detects the state of the switch through the detection circuit, when the first end and the second end of the switch are connected or the first end and the third end of the switch are connected, the fact that a user needs to enable a left steering lamp or a right steering lamp to be lightened is indicated, and at the moment, the input end and the output end of the switch circuit are conducted to supply power for the left steering lamp or the right steering lamp. It is thus clear that, in this application, neither be connected with the second end of self at user control switch's first end, also when being connected with the third end of self, switching circuit is the state of ending, and the first end of switch can not be electrified to avoid passing through the switch with the power and leaking to the human body, avoid causing harm to the human body, also can avoid the production of phenomena such as electric spark, thereby reduce vehicle light control circuit's risk.)

1. A vehicle light control circuit is characterized by comprising a central processing unit, a switch circuit, a detection circuit and a switch;

the first end of the central processing unit is connected with the control end of the switch circuit, the output end of the switch circuit is connected with the first end of the switch and the first end of the detection circuit, the input end of the switch circuit is connected with a power supply, the second end of the central processing unit is connected with the second end of the detection circuit, the third end of the detection circuit is connected with the second end of the switch and the power supply end of the left turn light, and the fourth end of the detection circuit is connected with the third end of the switch and the power supply end of the right turn light;

the central processing unit is used for controlling the conduction of the input end and the output end of the switch circuit when the first end and the second end of the switch are connected, so that the power supply supplies power to the left turn light; when the first end and the third end of the switch are connected, the input end and the output end of the switch circuit are controlled to be conducted, so that the power supply supplies power to the right steering lamp.

2. The vehicle light control circuit of claim 1, wherein the switch circuit comprises a controllable switch module, the control terminal of the controllable switch module being the control terminal of the switch circuit, a first terminal of the controllable switch module being connected to the power source, and a second terminal of the controllable switch module being connected to the first terminal of the switch.

3. The vehicle light control circuit of claim 2, wherein the controllable switch module comprises a first controllable switch and the second controllable switch;

the control end of the first controllable switch is the control end of the switch circuit, the first end of the first controllable switch is connected with the control end of the second controllable switch, the second end of the first controllable switch is grounded, the first end of the second controllable switch is the input end of the switch circuit, and the second end of the second controllable switch is the output end of the switch circuit.

4. A vehicle light control circuit according to claim 3, wherein the first controllable switch is a negative-positive-negative NPN transistor and the second controllable switch is a positive-negative-positive PNP transistor;

the base electrode of the NPN triode is the control end of the first controllable switch, the collector electrode of the NPN triode is the first end of the first controllable switch, the emitter electrode of the NPN triode is the second end of the first controllable switch, the base electrode of the PNP triode is the control end of the second controllable switch, the emitter electrode of the PNP triode is the first end of the second controllable switch, and the collector electrode of the PNP triode is the second end of the second controllable switch.

5. The vehicle light control circuit of claim 3, wherein the switching circuit further comprises a first resistor and a second resistor;

one end of the first resistor is connected with the first end of the first controllable switch, the other end of the first one-to-one group is respectively connected with the control end of the second controllable switch and one end of the second resistor, and the other end of the second resistor is connected with the first end of the second controllable switch.

6. A vehicle light control circuit according to claim 3, wherein the switch circuit further comprises a third resistor disposed between the first terminal of the central processing unit and the control terminal of the first controllable switch.

7. The vehicle light control circuit of any one of claims 1-6, wherein the detection circuit comprises a fourth resistor, a fifth resistor, and a low voltage power supply;

the second end of the central processing unit is connected with the low-voltage power supply and the first end of the switch, one end of the fourth resistor is connected with the second end of the switch, one end of the fifth resistor is connected with the third end of the switch, and the other end of the fourth resistor and the other end of the fifth resistor are both grounded;

the central processor is specifically configured to detect a level of a second terminal of the central processor, and when a low level is detected, control the input terminal and the output terminal of the switch circuit to be turned on to supply power to the left turn light or the right turn light.

8. The vehicle light control circuit of claim 7, wherein the detection circuit further comprises a sixth resistor, a seventh resistor, and a capacitor;

one end of the sixth resistor is connected with the second end of the central processing unit, the other end of the sixth resistor is respectively connected with one end of the seventh resistor, one end of the capacitor and the first end of the switch, the other end of the seventh resistor is connected with the low-voltage power supply, and the other end of the capacitor is grounded.

9. The vehicle light control circuit of claim 7, wherein the switching circuit further comprises a first anti-backup module, and the detection circuit further comprises a second anti-backup module; the first backflow prevention module is arranged between the output end of the switch circuit and the first end of the switch, and the second backflow prevention module is arranged between the first end of the detection circuit and the first end of the switch circuit.

10. The vehicle light control circuit of claim 9, wherein the first anti-backup module comprises a first diode and the second anti-backup module comprises a second diode;

the anode of the first diode is connected with the output end of the switch circuit, the cathode of the first diode is respectively connected with the cathode of the second diode and the first end of the switch, and the anode of the second diode is connected with the first end of the detection circuit.

Technical Field

The invention relates to the field of power electronics, in particular to a vehicle light control circuit.

Background

The lighting mode of controlling the left steering lamp and the right steering lamp of the electric vehicle in the prior art is as follows: specifically, the power supply is connected with a first end of the switch, a second end of the switch is connected with a power supply end of the left turn light, a third end of the switch is connected with a power supply end of the right turn light, the power supply continuously outputs the power supply, when the first end and the second end of the user control switch are connected, the power supply supplies power to the left turn light, and the left turn light is on; when the first end and the third end of the user control switch are connected, the power supply supplies power to the right steering lamp, and the right steering lamp is turned on.

By using the control mode, although the control of the left and right steering lamps can be realized, the power supply needs to continuously output the power supply, and the first end of the switch is provided with the power supply, so that the power supply is likely to leak to a human body in a rainy or humid environment to cause certain harm to the human body, and in addition, the phenomenon of electric sparks and the like is likely to be easily generated by continuously outputting the power supply, so that certain potential safety hazard is brought to a control circuit.

Disclosure of Invention

The invention aims to provide a vehicle light control circuit, which avoids the leakage of a power supply to a human body through a switch, avoids the damage to the human body, and can also avoid the generation of phenomena such as electric sparks and the like, thereby reducing the risk of the vehicle light control circuit.

In order to solve the technical problem, the invention provides a vehicle light control circuit, which comprises a central processing unit, a switch circuit, a detection circuit and a switch;

the first end of the central processing unit is connected with the control end of the switch circuit, the output end of the switch circuit is connected with the first end of the switch and the first end of the detection circuit, the input end of the switch circuit is connected with a power supply, the second end of the central processing unit is connected with the second end of the detection circuit, the third end of the detection circuit is connected with the second end of the switch and the power supply end of the left turn light, and the fourth end of the detection circuit is connected with the third end of the switch and the power supply end of the right turn light;

the central processing unit is used for controlling the conduction of the input end and the output end of the switch circuit when the first end and the second end of the switch are connected, so that the power supply supplies power to the left turn light; when the first end and the third end of the switch are connected, the input end and the output end of the switch circuit are controlled to be conducted, so that the power supply supplies power to the right steering lamp.

Preferably, the switch circuit includes a controllable switch module, a control end of the controllable switch module is a control end of the switch circuit, a first end of the controllable switch module is connected to the power supply, and a second end of the controllable switch module is connected to the first end of the switch.

Preferably, the controllable switch module comprises a first controllable switch and the second controllable switch;

the control end of the first controllable switch is the control end of the switch circuit, the first end of the first controllable switch is connected with the control end of the second controllable switch, the second end of the first controllable switch is grounded, the first end of the second controllable switch is the input end of the switch circuit, and the second end of the second controllable switch is the output end of the switch circuit.

Preferably, the first controllable switch is a negative electrode-positive electrode-negative electrode NPN triode, and the second controllable switch is a positive electrode-negative electrode-positive electrode PNP triode;

the base electrode of the NPN triode is the control end of the first controllable switch, the collector electrode of the NPN triode is the first end of the first controllable switch, the emitter electrode of the NPN triode is the second end of the first controllable switch, the base electrode of the PNP triode is the control end of the second controllable switch, the emitter electrode of the PNP triode is the first end of the second controllable switch, and the collector electrode of the PNP triode is the second end of the second controllable switch.

Preferably, the switch circuit further comprises a first resistor and a second resistor;

one end of the first resistor is connected with the first end of the first controllable switch, the other end of the first one-to-one group is respectively connected with the control end of the second controllable switch and one end of the second resistor, and the other end of the second resistor is connected with the first end of the second controllable switch.

Preferably, the switch circuit further includes a third resistor, and the third resistor is disposed between the first end of the central processing unit and the control end of the first controllable switch.

Preferably, the detection circuit comprises a fourth resistor, a fifth resistor and a low-voltage power supply;

the second end of the central processing unit is connected with the low-voltage power supply and the first end of the switch, one end of the fourth resistor is connected with the second end of the switch, one end of the fifth resistor is connected with the third end of the switch, and the other end of the fourth resistor and the other end of the fifth resistor are both grounded;

the central processor is specifically configured to detect a level of a second terminal of the central processor, and when a low level is detected, control the input terminal and the output terminal of the switch circuit to be turned on to supply power to the left turn light or the right turn light.

Preferably, the detection circuit further comprises a sixth resistor, a seventh resistor, and a capacitor;

one end of the sixth resistor is connected with the second end of the central processing unit, the other end of the sixth resistor is respectively connected with one end of the seventh resistor, one end of the capacitor and the first end of the switch, the other end of the seventh resistor is connected with the low-voltage power supply, and the other end of the capacitor is grounded.

Preferably, the switch circuit further comprises a first backflow prevention module, and the detection circuit further comprises a second backflow prevention module; the first backflow prevention module is arranged between the output end of the switch circuit and the first end of the switch, and the second backflow prevention module is arranged between the first end of the detection circuit and the first end of the switch circuit.

Preferably, the first backflow prevention module comprises a first diode, and the second backflow prevention module comprises a second diode;

the anode of the first diode is connected with the output end of the switch circuit, the cathode of the first diode is respectively connected with the cathode of the second diode and the first end of the switch, and the anode of the second diode is connected with the first end of the detection circuit.

The application provides a vehicle light control circuit, including central processing unit, switch circuit, detection circuitry and switch, central processing unit passes through detection circuitry detection switch's state, and when the first end of switch was connected with the second end or the first end of switch was connected with the third end, it needs to make left indicator or right indicator light to show the user, and this moment, make switch circuit's input and output switch on, for left indicator or right indicator light power supply. It is thus clear that, in this application, neither be connected with the second end of self at user control switch's first end, also when being connected with the third end of self, switching circuit is the state of ending, and the first end of switch can not be electrified to avoid passing through the switch with the power and leaking to the human body, avoid causing harm to the human body, also can avoid the production of phenomena such as electric spark, thereby reduce vehicle light control circuit's risk.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed in the prior art and the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a block diagram of a vehicle light control circuit according to the present invention;

fig. 2 is a specific circuit schematic diagram of a vehicle light control circuit provided by the invention.

Detailed Description

The core of the invention is to provide a vehicle light control circuit, which avoids the leakage of a power supply to a human body through a switch, avoids the damage to the human body, and can also avoid the generation of phenomena such as electric sparks and the like, thereby reducing the risk of the vehicle light control circuit.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, fig. 1 is a block diagram of a vehicle light control circuit according to the present invention, which includes a central processing unit 11, a switch circuit 12, a detection circuit 13 and a switch 14;

the first end of the central processing unit 11 is connected with the control end of the switch circuit 12, the output end of the switch circuit 12 is connected with the first end of the switch 14 and the first end of the detection circuit 13, the input end of the switch circuit 12 is connected with a power supply, the second end of the central processing unit 11 is connected with the second end of the detection circuit 13, the third end of the detection circuit 13 is connected with the second end of the switch 14 and the power supply end of the left turn light, and the fourth end of the detection circuit 13 is connected with the third end of the switch 14 and the power supply end of the right turn light;

the central processing unit 11 is used for controlling the input end and the output end of the switch circuit 12 to be conducted when the first end and the second end of the switch 14 are connected, so that the power supply supplies power to the left turn light; when the first terminal and the third terminal of the switch 14 are connected, the input terminal and the output terminal of the switch circuit 12 are controlled to be conducted, so that the power supply supplies power to the right turn lamp.

The method for controlling the electric quantity of the left steering lamp or the right steering lamp in the prior art has certain potential safety hazards. In order to solve the technical problem, the design idea of the application is as follows: the module is designed to detect the state of the switch 14, and when the switch 14 is detected to be dialed to a left turn light or a right turn light, namely, when the turn light needs to be lightened, the power supply is controlled to output the power supply to the first end of the switch 14, so that the power supply supplies power to the left turn light or the right turn light through the first end and the second end/the third end of the switch 14. It is also considered that it is costly to use a separate detection chip, such as an MCU (micro controller Unit), to detect the state of the switch 14. The design idea of the application is as follows: and a central processing unit 11 in the electric vehicle is multiplexed, and relevant circuits are configured to realize detection of the connection state of the switch 14 and output control of the power supply.

Specifically, the vehicle light control circuit in this application includes switch circuit 12 and detection circuit 13, and central processing unit 11 passes through detection circuit 13 and detects the connection state of switch 14, and then central processing unit 11 is according to the on-state of the state control switch circuit 12 of detected switch 14, and then decides whether to export the power to the power end of indicator. Specifically, when the first end and the second end of the switch 14 are connected, it is determined that the left turn signal lamp is turned on, at this time, the central processing unit 11 controls the switching circuit 12 to be turned on according to the state of the switch 14, and since the output end of the switching circuit 12 is connected to the power supply end of the left turn signal lamp, the power supply source-the switching circuit 12-the first end of the switch 14-the second end of the switch 14-the power supply end of the left turn signal lamp form a loop, and the left turn signal lamp is turned on. And a loop is not formed between the power supply, the switch circuit 12, the first end of the switch 14, the third end of the switch 14 and the power supply end of the right turn light, and the right turn light is not on. Similarly, when the first end and the third end of the switch 14 are connected, it is determined that the right turn signal lamp is turned on by the user, at this time, the central processing unit 11 controls the switching circuit 12 to be turned on according to the state of the switch 14, and since the output end of the switching circuit 12 is connected with the power supply end of the right turn signal lamp, the power supply source-the switching circuit 12-the first end of the switch 14-the third end of the switch 14-the power supply end of the right turn signal lamp form a loop, and the right turn signal lamp is turned on. And a loop is not formed between the power supply source and the switch circuit 12, the first end of the switch 14, the second end of the switch 14 and the power supply end of the left turn light, and the left turn light is not lighted.

The method for controlling the left turn light or the right turn light to be turned on may be: the power supply is continuously supplied to the steering lamp so that the steering lamp is normally on, or the power supply is controlled to be interrupted to supply power to the left steering lamp or the right steering lamp so that the steering lamp flickers, and the method is not limited according to the actual situation.

The central processing unit 11 in the present application may be a processor inside a multiplexing vehicle, and the central processing unit 11 may also be used for detecting and monitoring states of various modules in the vehicle, and the present application is not limited specifically herein.

In addition, switching circuit 12 and detection circuitry 13 in this application can set up inside central processing unit 11 to can avoid extra occupation space and volume, thereby reduced vehicle light control circuit's volume, also avoid constituting the return circuit with the external world, cause the electric leakage.

The switch 14 may be, but is not limited to, a single-pole double-throw switch 14. Or a controllable switch controlled by a user according to an instruction, and the application is not particularly limited herein.

It can be seen that, in this application, when the first end of user control switch 14 is neither connected with the second end of self, also with the third end of self be connected, switching circuit 12 is the state of cutting off, and the first end of switch 14 can not be electrified to avoid passing through switch 14 with the power and leaking to the human body, avoid causing harm to the human body, also can avoid the production of phenomena such as electric spark, thereby reduce vehicle light control circuit's risk.

On the basis of the above-described embodiment:

referring to fig. 2, fig. 2 is a specific circuit diagram of a vehicle light control circuit according to the present invention.

As a preferred embodiment, the switch circuit 12 includes a controllable switch module, a control terminal of the controllable switch module is a control terminal of the switch circuit 12, a first terminal of the controllable switch module is connected to the power supply, and a second terminal of the controllable switch module is connected to a first terminal of the switch 14.

Specifically, the switch circuit 12 may include, but is not limited to, a controllable switch module, and when detecting that the first terminal of the switch 14 is connected to the second terminal/the third terminal, the central processor 11 controls the first terminal and the second terminal of the controllable switch module to be turned on, so that the power supply and the power supply terminals of the left turn signal lamp/the right turn signal lamp form a loop, thereby implementing control of the left turn signal lamp or the right turn signal lamp.

The signal for controlling the controllable switch module to be turned on or off may be, but is not limited to, a level signal.

As a preferred embodiment, the controllable switch module comprises a first controllable switch and a second controllable switch;

the control end of the first controllable switch is the control end of the switch circuit 12, the first end of the first controllable switch is connected with the control end of the second controllable switch, the second end of the first controllable switch is grounded, the first end of the second controllable switch is the input end of the switch circuit 12, and the second end of the second controllable switch is the output end of the switch circuit 12.

Specifically, when the controllable switch module in this embodiment includes the first controllable switch and the second controllable switch, the central processing unit 11 controls the first controllable switch to be in the on or off state, and further, the second controllable switch is in the on state, at this time, the power supply supplies power to the left turn signal lamp/the right turn signal lamp and the like through the first end and the second end of the second controllable switch, and the first end and the second end/the third end of the switch 14, so as to realize the lighting of the left turn signal lamp/the right turn signal lamp.

It can be seen that in the present embodiment, a manner of controlling the controllable switch to be turned on or off is used, and a manner of controlling the channel between the power supply and the first end of the switch 14 to be turned on and then turned off is simple and reliable.

As a preferred embodiment, the first controllable switch is an NPN (negative-positive-negative) transistor, the second controllable switch is a PNP (positive-negative-positive,

positive-negative-positive) transistor;

the base electrode of the NPN triode is the control end of the first controllable switch, the collector electrode of the NPN triode is the first end of the first controllable switch, the emitter electrode of the NPN triode is the second end of the first controllable switch, the base electrode of the PNP triode is the control end of the second controllable switch, the emitter electrode of the PNP triode is the first end of the second controllable switch, and the collector electrode of the PNP triode is the second end of the second controllable switch.

In particular, this embodiment is intended to define a specific implementation manner of the first controllable switch and the second controllable switch, wherein the first controllable switch may be, but is not limited to, an NPN transistor, and the second controllable switch may be, but is not limited to, a PNP transistor. When central processing unit 11 detects the first end and the second end/the third end connection of switch 14 through detection circuitry 13, output high level, the NPN triode switches on this moment, and the low level signal is received to the base of PNP triode to the PNP triode switches on, and power supply passes through the emitting pole and the collecting electrode of PNP triode and carries the power to the first end of switch 14, thereby for left indicator or right indicator power supply. Similarly, when the central processing unit 11 detects through the detection circuit 13 that the first end of the switch 14 is not connected to the second end or the third end, the low level is output, the NPN triode is turned off at this time, the high level signal is received by the base of the PNP triode, the PNP triode is turned off, and the power supply end channel of the left turn light/the right turn light are turned off, so that the left turn light/the right turn light are not turned on.

Of course, the first controllable switch and the second controllable switch are not limited to the above examples, and may be other electronic switches 14 for implementing the above functions, and the application is not limited thereto.

In addition, the combination of the NPN transistor and the PNP transistor in this embodiment not only can implement the function of the control circuit, but also has a simple and reliable implementation manner.

As a preferred embodiment, the switch circuit 12 further includes a first resistor and a second resistor;

one end of the first resistor is connected with the first end of the first controllable switch, the other end of the first group is respectively connected with the control end of the second controllable switch and one end of the second resistor, and the other end of the second resistor is connected with the first end of the second controllable switch.

In this embodiment, the first resistor and the second resistor are used for dividing voltage to divide the voltage output by the power supply, so that the voltage output by the power supply outputs a proper voltage to the first end of the first controllable switch and the control end of the second controllable switch. In addition, a certain voltage difference can be formed between the first end and the control end of the second controllable switch through the second resistor, so that the reliability of the actions of the first controllable switch and the second controllable switch is ensured.

The voltage output by the power supply may be, but is not limited to, 48V.

In addition, when the central processing unit controls the left turn signal lamp or the right turn signal lamp to be turned on, the central processing unit can output a high level and a low level with a duty ratio of 50% for 200ms through the first end of the central processing unit, and at the moment, the external turn signal lamp is in a state of being turned on for 100ms and being turned off for 100 ms. When the lifting amount is not controlled, the first end of the self is 0V, and the external turn signal lamp is kept turned off.

As a preferred embodiment, the switch circuit 12 further includes a third resistor, and the third resistor is disposed between the first end of the central processing unit 11 and the control end of the first controllable switch.

The third resistor in this embodiment is a current-limiting resistor, and can prevent the voltage at the first end of the central processing unit 11 from being clamped to the on-state voltage of the first controllable switch, wherein when the first controllable switch is an NPN transistor, the voltage at the first end of the central processing unit 11 is prevented from being clamped at 0.7V, and in addition, the third resistor can also prevent the base current from being too large, so as to avoid the transistor from being burned out, and further ensure the safety and reliability of the control circuit.

As a preferred embodiment, the detection circuit 13 includes a fourth resistor, a fifth resistor and a low voltage power supply;

the second end of the central processing unit 11 is connected with the low-voltage power supply and the first end of the switch 14, one end of a fourth resistor is connected with the second end of the switch 14, one end of a fifth resistor is connected with the third end of the switch 14, and the other end of the fourth resistor and the other end of the fifth resistor are both grounded;

the central processing unit 11 is specifically configured to detect a level of a second terminal of the central processing unit, and when a low level is detected, control the input terminal and the output terminal of the switch circuit 12 to be turned on to supply power to the left turn light or the right turn light.

The embodiment aims to provide a specific implementation manner of the detection circuit 13, specifically, when the detection circuit includes a fourth resistor, a fifth resistor and a low-voltage power supply, when the first end and the second end of the switch 14 are connected or the first end and the third end of the switch 14 are connected, the voltage at the first end of the switch 14 is pulled down to a low level, at this time, the second end of the central processing unit 11 detects the low level, and then the switch circuit 12 is controlled to be turned on; when the first terminal of the switch 14 is connected to neither the second terminal nor the third terminal, the first terminal of the switch 14, that is, the second terminal of the cpu 11, is at a high level, and at this time, the switch circuit 12 is controlled to be turned off.

In addition, the voltage output by the low voltage power supply is less than the voltage output by the power supply and is insufficient to illuminate the left turn signal or the right turn signal, which may be, but is not limited to, 3.3V. That is, when the first end of the switch 14 is connected to the second end or the first end is connected to the third end, the left turn signal lamp or the right turn signal lamp is not turned on, and only when the power supply outputs power to the power source end of the left turn signal lamp or the right turn signal lamp is turned on.

It can be seen that, when the detection circuit 13 includes the fourth resistor, the fifth resistor and the low-voltage power supply, the function of the detection circuit 13 can be realized, and the realization mode is simple and reliable.

As a preferred embodiment, the detection circuit 13 further includes a sixth resistor, a seventh resistor, and a capacitor;

one end of the sixth resistor is connected to the second end of the central processing unit 11, the other end of the sixth resistor is connected to one end of the seventh resistor, one end of the capacitor and the first end of the switch 14, the other end of the seventh resistor is connected to the low-voltage power supply, and the other end of the capacitor is grounded.

Specifically, the sixth resistor is used for limiting current, and the seventh resistor is used for dividing voltage with the fourth resistor or the fifth resistor, so that when the fourth resistor or the fifth resistor is grounded, the second end of the central processing unit 11 can stably detect a low level; the capacitor functions as a filter to ensure the reliability of the detection circuit 13 and avoid noise interference.

As a preferred embodiment, the switch circuit 12 further includes a first backflow prevention module, and the detection circuit 13 further includes a second backflow prevention module; the first backflow prevention module is arranged between the output end of the switch circuit 12 and the first end of the switch 14, and the second backflow prevention module is arranged between the first end of the detection circuit 13 and the first end of the switch circuit 12.

Considering that the output terminal of the switch circuit 12 and the first terminal of the detection circuit 13 are both connected to the first terminal of the switch 14, the power supply connected to the switch circuit 12 may flow back to the detection circuit 13, and the low voltage power supply connected to the detection circuit 13 may flow back to the switch circuit 12.

Therefore, the first end backflow prevention module in this embodiment is used to prevent the power output by the low-voltage power supply from flowing backward to the switch circuit 12, and the second backflow prevention module is used to prevent the power output by the power supply from flowing backward to the detection circuit 13, so as to avoid damage to each other.

As a preferred embodiment, the first backflow prevention module comprises a first diode, and the second backflow prevention module comprises a second diode;

the anode of the first diode is connected to the output terminal of the switch circuit 12, the cathode of the first diode is connected to the cathode of the second diode and the first terminal of the switch 14, respectively, and the anode of the second diode is connected to the first terminal of the detection circuit 13.

Specifically, by using the single-phase conduction characteristic of the diode, the diode can be used as a specific implementation manner of the backflow prevention module, and can also be used as other implementation manners, which is not particularly limited herein.

It is to be noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus 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 apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.