Equipment switching circuit

Abstract

The utility model relates to the technical field of power electronics, and provides an equipment switching circuit, which comprises a battery, a switch, an operation enabling loop, a control power supply loop, an MCU control loop and a driving power supply loop, and is characterized in that a normally closed contact of the switch is connected with a first end of the operation enabling loop, and a normally open contact of the switch is connected with a first end of the control power supply loop; when the equipment is in a shutdown state, the normally closed contact is switched on, the normally open contact is switched off, the operation enabling loop is switched on, and the control power supply loop, the MCU control loop and the driving power supply loop are switched off; and after the normally open contact is conducted, the MCU control loop locks and controls the closing of the power supply loop according to the level change of the third end in the operation enabling loop, and controls the driving power supply loop to drive the equipment to operate. According to the equipment switching circuit provided by the utility model, the battery consumption is low when the equipment is shut down, the standby time of the battery can be effectively prolonged, the equipment is prevented from forcibly working in an under-voltage state, the battery is protected, misoperation is avoided, and the equipment is more reliable to run.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, specifically to a device switching circuit. Background Technology

[0002] Currently, most battery-powered electronic devices on the market use the following switching circuit: Under the control of the switch, the battery supplies power to the device through a control power circuit or a drive power circuit. The battery is also directly connected to the drive power circuit. When the switch is open, the battery continues to supply power to both the drive power circuit and the MCU control circuit (e.g., ...). Figure 1 (As shown). This switching circuit has the following problems: 1. The switch controls whether the control power circuit is energized or not, but there is no switch control for the drive power circuit. If the switch is malfunctioning, it will directly cause the equipment to run; 2. In standby or shutdown mode, the battery still supplies power to the drive power circuit and the MCU control circuit, resulting in excessive battery power consumption. Utility Model Content

[0003] To solve the above-mentioned technical problems, this utility model provides a device switching circuit that consumes less battery power when the device is off, effectively extends the battery standby time, prevents the device from being forced to work under low voltage, protects the battery, avoids misoperation, and makes the device operation more reliable.

[0004] The technical solutions adopted in this utility model are as follows:

[0005] This utility model provides a device switching circuit, including: a battery, a switch, a running enable circuit, a control power supply circuit, an MCU control circuit, and a drive power supply circuit; the switch includes a stationary contact, a normally closed contact, and a normally open contact. The stationary contact is connected to the positive terminal of the battery, and the normally closed contact is connected to the first terminal of the running enable circuit; the second terminal of the running enable circuit is connected to the negative terminal of the battery, and the third terminal of the running enable circuit is connected to the first terminal of the MCU control circuit, so that the MCU control circuit can detect the level change of the third terminal of the running enable circuit; the first terminal of the control power supply circuit is connected to the normally open contact to obtain a power-on signal, and the second terminal of the control power supply circuit is connected to the second terminal of the MCU control circuit to receive a latch signal from the MCU control circuit; the control power supply circuit... The third terminal of the control power circuit is connected to the third terminal of the MCU control circuit to supply power to the MCU control circuit. The fourth terminal of the control power circuit is connected to the positive terminal of the battery to obtain power from the battery when the control power circuit is closed. The drive power circuit is connected to the MCU control circuit so that the drive power circuit drives the device to operate under the control of the MCU control circuit. When the device is in the off state, the normally closed contact is turned on, the normally open contact is turned off, the operation enable circuit is closed, and the control power circuit, the MCU control circuit, and the drive power circuit are turned off. After the normally closed contact is turned off and the normally open contact is turned on, the MCU control circuit locks the control power circuit closed according to the level change of the third terminal in the operation enable circuit and controls the drive power circuit to drive the device to operate.

[0006] In addition, the device switching circuit proposed according to this utility model may also have the following additional technical features:

[0007] According to one embodiment of the present invention, the operation enable circuit includes a first resistor, a second resistor, and a first switching transistor connected in sequence. One end of the first resistor is connected to the first end of the operation enable circuit. A third resistor is electrically connected between the first resistor and the second resistor and then grounded. One end of a delay capacitor is connected to the grounded end of the third resistor, and the other end is connected to the connection line between the first resistor and the second resistor. The base of the first switching transistor is connected to the second resistor. The collector of the first switching transistor is connected to the third end of the operation enable circuit. The emitter of the first switching transistor is grounded.

[0008] According to one embodiment of the present invention, the first terminal of the MCU control circuit is connected to the third terminal of the MCU control circuit through the third terminal of the operation enable circuit and the fourth resistor.

[0009] According to one embodiment of the present invention, the control power supply circuit includes a fifth resistor, a first diode, a second switch, a sixth resistor, a third switch, a seventh resistor, an eighth resistor, a fourth switch, a ninth resistor, and a second diode. The first terminal of the control power supply circuit is connected to the base of the second switch through the fifth resistor and the first diode. The emitter of the second switch is grounded. The collector of the second switch is connected to the base of the third switch through the sixth resistor. The collector of the third switch is connected to the sixth resistor through the seventh resistor. The emitter of the third switch is also connected to the battery through the fourth terminal of the control power supply circuit. The collector of the third switch is connected to the base of the fourth switch through the eighth resistor. The collector of the third switch is also connected to the collector of the fourth switch. The emitter of the fourth switch is connected to the third terminal of the control power supply circuit. The second terminal of the control power supply circuit is connected to the base of the second switch through the ninth resistor and the second diode.

[0010] According to one embodiment of the present invention, a tenth resistor and a step-down circuit are provided between the third and fifth terminals of the control power supply circuit.

[0011] According to one embodiment of the present invention, a Zener diode with one end grounded is connected to the connection line between the fourth switch and the eighth resistor.

[0012] According to one embodiment of the present invention, the control power supply circuit further includes an eleventh resistor, one end of which is connected to the base of the second switching transistor, and the other end of which is grounded.

[0013] According to one embodiment of the present invention, the first end of the drive power circuit is connected to the normally open contact so that the battery supplies power to the driver of the drive power circuit; the third end of the drive power circuit is connected to the fifth end of the control power circuit so that the control power circuit supplies power to the driver chip of the drive power circuit.

[0014] The beneficial effects of this utility model are:

[0015] The device switching circuit of this utility model has the following characteristics: when the device is in the off state, the normally closed contact is closed and the normally open contact is open. The battery consumption is only the current flowing through the operation enable circuit, resulting in low battery power consumption and effectively extending the battery standby time. When the battery voltage is insufficient, the device cannot be driven by the drive power circuit, which can prevent the device from being forced to work under low voltage conditions, thereby forcing the user to charge and protecting the battery. The control power circuit, operation enable circuit, and drive power circuit are interlocked by the normally closed and normally open contacts of the switch, which can prevent malfunctions and make the device operation more reliable. Attached Figure Description

[0016] Figure 1 This is a type of device switching circuit currently used in the market;

[0017] Figure 2 This is a schematic diagram of the device switching circuit according to an embodiment of the present utility model;

[0018] Figure 3 A circuit diagram of the operation enable circuit according to one embodiment of the present invention;

[0019] Figure 4 This is a circuit diagram of the control power supply circuit according to one embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] like Figure 2 As shown, the device switching circuit of this embodiment includes: a battery 10, a switch 20, a running enable circuit 30, a control power circuit 40, an MCU control circuit 50, and a drive power circuit 60; the switch 20 includes a stationary contact 21, a normally closed contact 22, and a normally open contact 23. The stationary contact 21 is connected to the positive terminal of the battery 10, and the normally closed contact 22 is connected to the first terminal 31 of the running enable circuit 30; the second terminal 32 of the running enable circuit 30 is connected to the negative terminal of the battery 10, and the third terminal 33 of the running enable circuit 30 is connected to the first terminal 51 of the MCU control circuit 50, so that the MCU control circuit 50 detects the level change of the third terminal 33 of the running enable circuit 30; the first terminal 41 of the control power circuit 40 is connected to the normally open contact 23. The control power circuit 40 is connected to the second terminal 42 of the MCU control circuit 50 to receive the latch signal from the MCU control circuit 50. The control power circuit 40 is connected to the third terminal 53 of the MCU control circuit 50 to supply power to the MCU control circuit 50. The control power circuit 40 is connected to the positive terminal of the battery 10 to obtain power from the battery 10 when the control power circuit 40 is closed. The drive power circuit 60 is connected to the MCU control circuit 50. For example, the second terminal 62 of the drive power circuit 60 is connected to the fourth terminal 54 of the MCU control circuit 50 so that the drive power circuit 60 drives the device to operate under the control of the MCU control circuit 50.

[0022] When the device is powered off, normally closed contact 22 is closed, normally open contact 23 is open, the operation enable circuit 30 is closed, and the control power circuit 40, MCU control circuit 50, and drive power circuit 60 are open. After normally closed contact 22 is open and normally open contact 23 is closed, the MCU control circuit 50 locks the control power circuit 40 closed according to the level change of the third terminal 33 of the operation enable circuit 30, and controls the drive power circuit 60 to drive the device to run.

[0023] Understandably, when switch 20 is in the closed state (i.e., normally closed contact 22 is closed and normally open contact 23 is open), the control power circuit 40, MCU control circuit 50, and drive power circuit 60 are disconnected. The battery 10 consumes only the current flowing through the operation enable circuit 30, which is less than the power consumption of the battery 10 in standby mode for powering the drive power circuit 60 and MCU control circuit 50, effectively extending the standby time of the battery 10. When the battery 10 voltage is insufficient, the MCU control circuit 50 cannot detect the level change at the third terminal in the operation enable circuit 30, even if the control power circuit 40 is closed. The device cannot be driven by the drive power circuit 60, which prevents the device from being forced to work under low voltage. If the user wants the device to work normally, the battery 10 must be removed, fully charged, and then reconnected to work, thus forcing the user to charge and protecting the battery 10. Since the power supply of the MCU control circuit 50 comes from the control power circuit 40, once the control power circuit 40 is disconnected, the MCU control circuit 50 will also be disconnected, causing the drive power circuit 60 to be unable to drive the device to work under the control of the MCU control circuit 50. This can prevent the drive power circuit 60 from malfunctioning and make the device operation more reliable.

[0024] Specifically, if Figure 3 As shown, the operation enable circuit 30 may include a first resistor R1, a second resistor R2, and a first switch Q1 connected in sequence. One end of the first resistor R1 is connected to the first terminal 31 of the operation enable circuit 30, and the other end of the first resistor R1 is connected to the second resistor R2. The first resistor R1 and the second resistor R2 are electrically connected to a third resistor R3 and then grounded. One end of the delay capacitor C1 is connected to the ground terminal of the third resistor R3, and the other end is connected to the connection line between the first resistor R1 and the second resistor R2. The base of the first switch Q1 is connected to the second resistor R2, the collector of the first switch Q1 is connected to the third terminal 33 of the operation enable circuit 30, and the emitter of the first switch Q1 is grounded.

[0025] When the first switch Q1 is an NPN type switch: When the normally closed contact 22 is on and the normally open contact 23 is off, the battery 10 charges the delay capacitor C1 through the first resistor R1. At this time, the first switch Q1 is in the off state. When the normally closed contact 22 is off and the normally open contact 23 is on, the charged delay capacitor C1 begins to discharge to the base of the first switch Q1 through the second resistor R2, making the first switch Q1 on. At this time, the third terminal 33 of the operation enable circuit 30 connected to the first switch Q1 is at a low level. When the delay capacitor C1 finishes discharging, the first switch Q1 enters the off state. At this time, the third terminal 33 of the operation enable circuit 30 connected to the first switch Q1 is at a high level, so that the MCU control circuit 50 can lock the control power circuit 40 closed according to the level change of the third terminal 33 of the operation enable circuit 30 (from low level to high level).

[0026] It should be noted that when the battery voltage is insufficient, the charging voltage of the delay capacitor C1 is insufficient, and the switching transistor Q1 cannot be turned on. As a result, the MCU control circuit 50 cannot detect the level change of the third terminal 33 of the operation enable circuit 30. Even if the control power circuit 40 and the drive power circuit 60 are closed, the device cannot work under the control of the MCU control circuit 50, thus preventing the device from being forced to work under undervoltage conditions and protecting the battery 10.

[0027] In a specific embodiment of this utility model, the resistance value of the third resistor R3 can be in the megaΩ range. When the switch 20 is in the closed state, the battery 10 consumes the current flowing through the third resistor R3 and the leakage current on the delay capacitor C1. Therefore, when the device stops running, the current output by the battery 10 is in the μA range, which can effectively extend the standby time of the battery 10.

[0028] In a specific embodiment of this utility model, the first terminal 51 of the MCU control circuit 50 can be connected to the third terminal 53 of the MCU control circuit 50 through the third terminal 33 of the operation enable circuit 30 and the fourth resistor R4, so that the current output from the third terminal 43 of the control power circuit 40 can pass through the third terminal 53 of the MCU control circuit 50 and the fourth resistor R4 in sequence, and then through the first switching transistor Q1 to provide power to the collector of the first switching transistor Q1.

[0029] In one embodiment of this utility model, the control power supply circuit 40 may include a fifth resistor R5, a first diode D1, a second switch Q2, a sixth resistor R6, a third switch Q3, a seventh resistor R7, an eighth resistor R8, a fourth switch Q4, a ninth resistor R9, and a second diode D2. The first terminal 41 of the control power supply circuit 40 is connected to the base of the second switch Q2 through the fifth resistor R5 and the first diode D1. The emitter of the second switch Q2 is grounded, and the collector of the second switch Q2 is connected to the base of the third switch Q3 through the sixth resistor R6. The collector of the third switch Q3 is connected to the sixth resistor R6 through the seventh resistor R7. The emitter of the third switch Q3 is also connected to the battery 10 through the fourth terminal 44 of the control power circuit 40. The collector of the third switch Q3 is connected to the base of the fourth switch Q4 through the eighth resistor R8. The collector of the third switch Q3 is also connected to the collector of the fourth switch Q4. The emitter of the fourth switch Q4 is connected to the third terminal 43 of the control power circuit 40. The second terminal of the control power circuit 4040 is connected to the base of the second switch Q2 through the ninth resistor R9 and the second diode D2.

[0030] When the second switch Q2 is an NPN type switch, the third switch Q3 is a PNP type switch, and the fourth switch Q4 is an NPN type switch: When the normally open contact 23 is closed, the output current of the battery 10 can reach the base of the second switch Q2 through the first terminal 41 of the control power circuit 40, the fifth resistor R5, and the first diode D1, thus completing the circuit from the fourth terminal 44 to the sixth terminal of the control power circuit 40, thereby turning on the third switch Q3. Since the emitter of the third switch Q3 is connected to the fourth switch Q4 through the eighth resistor R8, the fourth switch Q4 is also turned on, thus closing the control power circuit 40. After the MCU control circuit 50 is powered on, it can send a latch signal to the second terminal 42 of the control power circuit 40 to lock the control power circuit 40 closed. When the device is in standby mode (i.e., normally open contact 23 is open, but control power circuit 40 is latched, but drive power circuit 60 is not powered), MCU control circuit 50 can be delayed to shut down, so that control power circuit 40 is disconnected from battery 10. At this time, control power circuit 40 and MCU control circuit 50 are in monitoring mode, and the machine can be started quickly.

[0031] In one embodiment of this utility model, a tenth resistor R10 and a step-down circuit U1 may be provided between the third terminal 43 and the fifth terminal 45 of the control power circuit 40, so that the control power circuit 40 can provide a lower voltage control power supply to the MCU control circuit 50.

[0032] In one embodiment of this utility model, a Zener diode ZD1 with one end grounded can be connected to the connection line between the fourth switch Q4 and the eighth resistor R8, thereby ensuring the stability of the base voltage of the fourth switch Q4 and improving the anti-interference capability and stability of the circuit.

[0033] In one embodiment of this utility model, the control power supply circuit 40 may further include an eleventh resistor R11. One end of the eleventh resistor R11 is connected to the base of the second switching transistor Q2, and the other end of the eleventh resistor R11 is grounded. The voltage division of the eleventh resistor R11 realizes the undervoltage protection of the switch 20 circuit, preventing the device from being forced to work under undervoltage conditions.

[0034] In one embodiment of the present invention, the first end 61 of the drive power circuit 60 can be connected to the normally open contact 23 so that the battery 10 supplies power to the driver of the drive power circuit 60; the third end 63 of the drive power circuit 60 can be connected to the fifth end 45 of the control power circuit 40 so that the control power circuit 40 supplies power to the driver chip of the drive power circuit 60.

[0035] like Figures 2 to 4 As shown, in a specific embodiment of this utility model, the operating mode of the device switching circuit is as follows:

[0036] No power mode: No battery 10 is connected to the device switching circuit, and the device switching circuit has no power.

[0037] Preparatory mode: When the device switching circuit is connected to battery 10, the device is in the off state, normally closed contact 22 is conducting, normally open contact 23 is open, the operation enable circuit 30 is closed, battery 10 charges the delay capacitor C1 through resistor R1, the first switching transistor Q1 is in the off state, and the control power circuit 40, MCU control circuit 50, and drive power circuit 60 are disconnected.

[0038] Pre-power-on mode: Normally closed contact 22 is open, normally open contact 23 is closed, and the output current of battery 10 flows through the first terminal 41 of control power circuit 40, causing control power circuit 40, MCU control circuit 50, and drive power circuit 60 to close. If MCU control circuit 50 detects that the third terminal 33 of run enable circuit 30 rises from low level to high level, it locks control power circuit 40 closed, allowing the device switching circuit to enter power-on mode; otherwise, the device switching circuit cannot enter power-on mode, and the device cannot work.

[0039] Power-on mode: The control power circuit 40 receives the latch signal from the MCU control circuit 50 and drives the power circuit 60 to drive the device to run under the control of the MCU control circuit 50.

[0040] Monitoring Mode: When the device is in standby mode, the MCU control circuit 50 locks the control power circuit 40 closed, the normally open contact 23 is open, and the drive power circuit 60 cannot receive power from the battery 10. The control power circuit 40 and the MCU control circuit 50 are in monitoring mode, allowing for rapid device startup. If the device does not provide a power-on command to the MCU control circuit 50 within a preset time (e.g., 20~30s), the MCU control circuit 50 stops outputting latch signals, the drive power circuit 60 is disconnected, and the device switching circuit enters standby mode.

[0041] Based on the foregoing content, the control power circuit 40 and the operation enable circuit 30 in the device switching circuit of this utility model can all be implemented with surface mount electronic components, and can all be soldered using SMT (Surface Mount Technology). Due to the small number of components used and their small size, production costs can be reduced significantly, the structure is more adaptable, and the lifespan is longer.

[0042] According to the device switching circuit of this utility model embodiment, when the device is in the off state, the normally closed contact is open and the normally open contact is closed. The battery consumption is only the current flowing through the operation enable circuit, and the battery power consumption is small, which can effectively extend the battery standby time. When the battery voltage is insufficient, the device cannot be driven by the drive power circuit, which can prevent the device from working under the undervoltage state, thereby forcing the user to charge and protecting the battery. The control power circuit, the operation enable circuit, and the drive power circuit are interlocked by the normally closed and normally open contacts of the switch, which can avoid malfunction and make the device operation more reliable.

[0043] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified.

[0044] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, indirect connection through an intermediate medium, internal communication between two components, or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0045] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0046] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0047] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A device switching circuit, characterized in that, include: Battery, switch, operation enable circuit, control power circuit, MCU control circuit and drive power circuit; The switch includes a stationary contact, a normally closed contact, and a normally open contact. The stationary contact is connected to the positive terminal of the battery, and the normally closed contact is connected to the first terminal of the operation enable circuit. The second terminal of the operation enable circuit is connected to the negative terminal of the battery, and the third terminal of the operation enable circuit is connected to the first terminal of the MCU control circuit, so that the MCU control circuit can detect the level change of the third terminal of the operation enable circuit. The first end of the control power circuit is connected to the normally open contact to obtain a power-on signal. The second end of the control power circuit is connected to the second end of the MCU control circuit to receive a latch signal from the MCU control circuit. The third end of the control power circuit is connected to the third end of the MCU control circuit to supply power to the MCU control circuit. The fourth end of the control power circuit is connected to the positive terminal of the battery to obtain power from the battery when the control power circuit is closed. The drive power supply circuit is connected to the MCU control circuit so that the drive power supply circuit drives the device to operate under the control of the MCU control circuit; When the device is powered off, the normally closed contact is turned on, the normally open contact is turned off, the operation enable circuit is closed, and the control power circuit, the MCU control circuit, and the drive power circuit are turned off. After the normally closed contact is turned off and the normally open contact is turned on, the MCU control circuit locks the control power circuit closed according to the level change of the third terminal in the operation enable circuit, and controls the drive power circuit to drive the device to run.

2. The device switching circuit according to claim 1, characterized in that, The operation enable circuit includes a first resistor, a second resistor, and a first switching transistor connected in sequence. One end of the first resistor is connected to the first end of the operation enable circuit. A third resistor is electrically connected between the first resistor and the second resistor and then grounded. One end of the delay capacitor is connected to the ground terminal of the third resistor, and the other end is connected to the connection line between the first resistor and the second resistor. The base of the first switching transistor is connected to the second resistor. The collector of the first switching transistor is connected to the third end of the operation enable circuit. The emitter of the first switching transistor is grounded.

3. The device switching circuit according to claim 2, characterized in that, The first terminal of the MCU control loop is connected to the third terminal of the MCU control loop through the third terminal of the operation enable loop and the fourth resistor.

4. The device switching circuit according to claim 1, characterized in that, The control power supply circuit includes a fifth resistor, a first diode, a second switch, a sixth resistor, a third switch, a seventh resistor, an eighth resistor, a fourth switch, a ninth resistor, and a second diode. The first terminal of the control power supply circuit is connected to the base of the second switch through the fifth resistor and the first diode. The emitter of the second switch is grounded. The collector of the second switch is connected to the base of the third switch through the sixth resistor. The collector of the third switch is connected to the sixth resistor through the seventh resistor. The emitter of the third switch is also connected to the battery through the fourth terminal of the control power supply circuit. The collector of the third switch is connected to the base of the fourth switch through the eighth resistor. The collector of the third switch is also connected to the collector of the fourth switch. The emitter of the fourth switch is connected to the third terminal of the control power supply circuit. The second terminal of the control power supply circuit is connected to the base of the second switch through the ninth resistor and the second diode.

5. The device switching circuit according to claim 4, characterized in that, A tenth resistor and a step-down circuit are provided between the third and fifth terminals of the control power supply circuit.

6. The device switching circuit according to claim 4, characterized in that, A Zener diode with one end grounded is connected to the connection line between the fourth switch and the eighth resistor.

7. The device switching circuit according to claim 4, characterized in that, The control power supply circuit also includes an eleventh resistor, one end of which is connected to the base of the second switching transistor, and the other end of which is grounded.

8. The device switching circuit according to claim 1 or 6, characterized in that, The first end of the drive power circuit is connected to the normally open contact so that the battery supplies power to the driver of the drive power circuit; the third end of the drive power circuit is connected to the fifth end of the control power circuit so that the control power circuit supplies power to the driver chip of the drive power circuit.

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