CN215117451U

CN215117451U - Timing switch device based on USB interface

Info

Publication number: CN215117451U
Application number: CN202121461728.6U
Authority: CN
Inventors: 陈润泽; 蔡楚洪; 吴锋; 梁志平; 朱锦钊
Original assignee: Guangzhou Fangtu Technology Co ltd
Current assignee: Guangzhou Fangtu Technology Co ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2021-12-10
Anticipated expiration: 2031-06-29

Abstract

The utility model discloses a time switch machine device based on USB interface, include: the power supply control circuit comprises a main control board, a power supply input interface, an EMI filter circuit, an EMC filter circuit, an AC-DC conversion circuit, a DC-DC conversion circuit, a power supply switch circuit for providing a starting power supply, a clock circuit for providing calibration time, an optical coupling switch circuit, a USB interface circuit and a switch time setting interface for acquiring set switch-on and switch-off time; the power supply input is transmitted to the main control panel through an EMI filter circuit, an EMC filter circuit, an AC-DC conversion circuit and a DC-DC conversion circuit, the USB interface circuit detects the on-off state, and the optocoupler switch circuit outputs an on-off signal of the main control panel; the main control board is provided with a startup and shutdown detection pin, and the USB interface circuit is connected with the startup and shutdown detection pin of the main control board. The utility model discloses a USB interface communication has overcome the present limitation that only carries out communication through 9 needle serial ports or RS485 interfaces.

Description

Timing switch device based on USB interface

Technical Field

The utility model relates to a time switch machine equipment technical field, concretely relates to time switch machine based on USB interface.

Background

With the development of society, self-service equipment gradually becomes mainstream, and power utilization problems such as power failure of equipment at night, power failure at fixed time, safety power failure and the like are concerned, for example, the host equipment with a computer needs to be powered off first and then powered off, the self-service equipment needs to be powered on in advance in non-working days due to electromagnetic interference of a power supply, and the like;

the existing timing startup and shutdown equipment has the following defects: 1. the timing on-off is mostly carried out by adopting an RS232 or RS485 interface, while a computer host of the common equipment has the structure that a 9-pin serial port or an RS485 interface is cancelled, only a USB interface is reserved, and the communication can not be carried out by adopting the RS232 or RS485 interface; 2. some devices are remotely turned on and off through the Internet, but cannot be applied to office environments only provided with a local area network, such as government places, and only turn off a computer and cannot cut off a rear-end power supply, so that hidden use troubles exist when the self-service equipment is provided with multiple accessories, and the self-service equipment only turns off the computer and cannot cut off the power supplies of other accessories; 3. the existing timing startup and shutdown equipment cannot set multiple groups of startup, is not used for the weekend of the equipment or cannot change the startup and shutdown time in one step; 4. the existing mode only aiming at one device and one computer host cannot be used under the condition that the computer hosts are powered off before the power supply of the device is turned off; 5. the power is mostly used in low power, and the use scene of the self-service equipment with higher power is less.

Disclosure of Invention

In order to overcome the defect and not enough that prior art exists, the utility model provides a time switch device based on USB interface, the utility model discloses a communication interface adopts the USB interface, can connect two host computers, has overcome prior art and only can carry out the limitation that communicates through 9 needle serial ports or RS485 interfaces to be equipped with USB and prevent static communication interface, need not the drive and can be direct and the computer communication, avoid the computer not have the interface of nine needle serial ports and can't communicate.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model provides a time switch device based on USB interface is equipped with the main control board, still includes: the power supply comprises a power supply input interface, an EMI filter circuit, an EMC filter circuit, an AC-DC conversion circuit, a DC-DC conversion circuit, a power supply switch circuit, a clock circuit, an optical coupling switch circuit, a USB interface circuit and a switching time setting interface;

the power input interface is connected with an alternating current power supply, the power input interface is connected with the input end of the EMI filter circuit, the output end of the EMI filter circuit is connected with the input end of the EMC filter circuit, the output end of the EMC filter circuit is connected with the input end of the AC-DC conversion circuit, the output end of the AC-DC conversion circuit is connected with the input end of the DC-DC conversion circuit, and the output end of the DC-DC conversion circuit is connected with the main control board;

the output end of the EMI filter circuit is connected with a power switch circuit, the power switch circuit is connected with a main control panel, and the power switch circuit is used for providing power for starting a timing switch device;

the clock circuit, the USB interface circuit, the optical coupling switch circuit and the on-off time setting interface are respectively connected with the main control board, the clock circuit is used for time calibration, the on-off time setting interface is used for acquiring set on-off time, the USB interface circuit is used for detecting on-off, and the optical coupling switch circuit is used for outputting on-off signals of the main control board;

the main control board is provided with a power on/off detection pin, the USB interface circuit is connected with the power on/off detection pin of the main control board, and the USB interface circuit comprises a USB power supply pin, a triode Q4, a base resistor R31, a collector resistor R30, an emitter resistor R32 and a grounding resistor R33;

the USB power supply pin is connected with a USB power supply and is connected with one end of a base resistor R31, the other end of the base resistor R31 is connected with a base electrode of a triode Q4, one end of a collector resistor R30 is connected with an output end of a DC-DC conversion circuit, the other end of the collector resistor R30 is connected with a collector electrode of a triode Q4, one end of an emitter resistor R32 is connected with an emitting electrode of the triode Q4, the other end of the emitter resistor R32 is connected with one end of a grounding resistor R33 and is connected with a switching detection pin of a main control board, and the other end of the grounding resistor R33 is grounded.

As a preferred technical scheme, the USB interface circuit is further provided with a bleeder circuit, the bleeder circuit includes a first bleeder resistor, a second bleeder resistor, and a third bleeder resistor, the first bleeder resistor, the second bleeder resistor, and the third bleeder resistor are connected in parallel, one end of the first bleeder resistor is connected to the USB power pin, and the other end of the first bleeder resistor is grounded.

As a preferred technical scheme, the USB static protection circuit is further arranged, and the USB static protection circuit is connected with a data transmission pin in the USB interface circuit in parallel.

As an optimized technical scheme, the USB detection circuit of other hosts is further arranged, the main control board is provided with other host on-off detection pins, the USB detection circuit of other hosts comprises a USB power resistor and a ground resistor, one end of the USB power resistor is connected with a USB power supply end, the other end of the USB power resistor is connected with one end of the ground resistor and is connected with other host on-off detection pins of the main control board, and the other end of the ground resistor is grounded.

As a preferred technical scheme, the device is further provided with an external key circuit, and the main control board is provided with a first external power-on key detection pin and a second external power-on key detection pin;

the external key circuit includes: the circuit comprises a triode Q2, a triode Q3, a resistor R14, a resistor R15, a resistor R26, a resistor R27, a resistor R28 and a resistor R29;

one end of the resistor R15 is connected with the output end of the AC-DC conversion circuit, the other end of the resistor R15 is connected with one end of a resistor R26 and is connected with one end of a first external power-on key, the other end of the first external power-on key is grounded, the other end of the resistor R26 is connected with the base electrode of a triode Q2, one end of the resistor R14 is connected with the output end of the DC-DC conversion circuit, the other end of the resistor R14 is connected with the emitter of the triode Q2 and is connected with a detection pin of the first external power-on key, and the collector of the triode Q2 is grounded;

one end of the resistor R28 is connected with the output end of the AC-DC conversion circuit, the other end of the resistor R28 is connected with one end of the resistor R29 and is connected with one end of a second external power-on key, the other end of the second external power-on key is grounded, the other end of the resistor R29 is connected with the base electrode of the triode Q3, one end of the resistor R27 is connected with the output end of the DC-DC conversion circuit, the other end of the resistor R27 is connected with the emitter of the triode Q3 and is connected with the detection pin of the second external power-on key, and the collector of the triode Q3 is grounded.

As an optimized technical scheme, the main control board is provided with a power on/off control pin, the optical coupling switch circuit is provided with a solid-state relay, the input end of the solid-state relay is connected with the power on/off control pin of the main control board, and the output end of the solid-state relay is connected with a computer power on key.

Preferably, the AC-DC conversion circuit is a circuit for converting AC220V to DC 5V, and the DC-DC conversion circuit is a circuit for converting DC 5V to DC 3.3V.

As a preferred technical scheme, the main control board is provided with a power switch control pin, and the power switch circuit includes: the LED driving circuit comprises a resistor R1, a resistor R2, a resistor R3, a triode Q1, a light emitting diode DS2, a diode D2, a direct current relay SLA-05VDC-SL-A, a resistor R38 and a capacitor C22;

one end of the light emitting diode DS2 is connected with the output end of the AC-DC conversion circuit, the other end of the light emitting diode DS2 is connected with one end of a resistor R1 and is connected with a collector of a triode Q1, one end of the resistor R2 is connected with a power switch control pin, the other end of the resistor R2 is connected with a base electrode of a triode Q1, one end of the resistor R3 is connected with a base electrode of a triode Q1, the other end of the resistor R3 is connected with an emitter electrode of the triode Q1, and the emitter electrode of the triode Q1 is grounded;

one end of a coil of the direct current relay is connected with the output end of the AC-DC conversion circuit, the other end of the coil of the direct current relay is connected with a collector of a triode Q1, two ends of the coil of the direct current relay are connected with a diode D2 in parallel, the negative electrode of the diode D2 is connected with the output end of the AC-DC conversion circuit, a normally open contact of the direct current relay is connected with a live wire input by an alternating current power supply, and the output end of the live wire is provided with a protective tube;

the resistor R38 is connected with the capacitor C22 in series, and after being connected in series, the resistor R38 is integrally connected in parallel with two ends of a normally open contact of the direct current relay.

As a preferred technical scheme, the input end of the EMI filter circuit is connected in series with the common mode inductor and in parallel with the filtering differential mode capacitor, the output ends of the EMI filter circuit are all provided with Y capacitors, one end of each Y capacitor is connected with one end of the output end, and the other end of each Y capacitor is connected with the ground wire.

According to the preferable technical scheme, the input end of the EMC filter circuit is connected with the filtering differential mode capacitor and the piezoresistor in parallel and is connected with the common mode inductor in series, the output ends of the EMC filter circuit are provided with Y capacitors, one end of each Y capacitor is connected with one end of each output end, and the other end of each Y capacitor is connected with the ground wire.

Compared with the prior art, the utility model, following advantage and beneficial effect have:

(1) the utility model discloses have the filtering and prevent surge and timing switch machine function, shut down earlier the outage again to self-service equipment's computer, and the device can connect two host computers to communication interface is USB, has overcome prior art and has only can carry out the limitation of communicating through 9 needle serial ports or RS485 interfaces.

(2) The utility model discloses be equipped with piezo-resistor and play the effect of filtering anti-surge, be equipped with EMC filter circuit and restrain electromagnetic interference.

(3) The utility model discloses be equipped with USB and prevent static communication interface, need not the drive and can directly communicate with the computer, avoid the computer not have the interface of nine-pin serial ports and can't communicate.

Drawings

FIG. 1 is a schematic diagram of an overall structure of a USB interface-based time switch device according to the present embodiment;

FIG. 2 is a schematic diagram of an EMI filter circuit according to an embodiment;

FIG. 3 is a schematic structural diagram of an EMC filter circuit according to the present embodiment;

FIG. 4 is a schematic diagram of the AC-DC converter circuit according to the present embodiment;

FIG. 5 is a schematic diagram of a DC-DC converter circuit according to the present embodiment;

fig. 6 is a schematic diagram of a pin arrangement structure of the main control board in this embodiment;

FIG. 7 is a schematic diagram of a power switch circuit according to the present embodiment;

FIG. 8 is a schematic diagram of a clock circuit according to the present embodiment;

fig. 9 is a schematic structural diagram of the optocoupler switch circuit according to this embodiment;

FIG. 10 is a schematic structural diagram of a USB interface circuit according to the present embodiment;

FIG. 11 is a schematic structural diagram of the USB ESD protection circuit of the present embodiment;

FIG. 12 is a schematic diagram of a USB detection circuit of another host of this embodiment;

FIG. 13 is a schematic diagram of an external key circuit according to the present embodiment;

fig. 14 is a schematic structural diagram of the buzzer in the present embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Examples

As shown in fig. 1, the present embodiment provides a timing switch device based on a USB interface, including: the power supply control circuit comprises a power supply input interface, an EMI filter circuit, an EMC filter circuit, an AC-DC conversion circuit, a DC-DC conversion circuit, a main control board, a power supply switch circuit, a power supply output interface, a clock circuit, an optical coupling switch circuit, a power on/off signal output interface, a USB interface circuit, an external key circuit and a switching time setting interface;

the power input interface is externally connected with an alternating current power supply, the alternating current power supply is input into the AC-DC conversion circuit to be converted into alternating current and direct current after passing through the EMI filter circuit and the EMC filter circuit, the output end of the AC-DC conversion circuit is connected with the power switch circuit to provide direct current voltage, and the output end of the AC-DC conversion circuit is connected with the DC-DC conversion circuit to perform direct current voltage reduction processing and output direct current supply voltage;

as shown in fig. 2, the EMI filter circuit is a 220V AC input, common mode signals are suppressed by selecting a high-power common mode inductor C4 and two Y capacitors CY1 and CY2, X2 is an X capacitor filter differential mode capacitor, and the filtered power (AC220V) of the module supplies power to the whole device; the parameter of the high-power common-mode inductor C4 is preferably 1mH10A, and the two Y capacitors CY1 and CY2 are preferably 332M/3300 pf;

as shown in FIG. 3, the EMC filter circuit is used for EMC filtering of an AC-DC conversion circuit, X3 is an X capacitor for filtering differential mode capacitance, L1 is a low-power common-mode inductor (preferably 10MH), two Y capacitors CY3 and CY4 suppress common-mode signals, the overall circuit suppresses electromagnetic interference of the AC-DC conversion circuit, wherein the two Y capacitors CY3 and CY4 are preferably 332M/3300pf, and an anti-surge resistor R48 can prevent surge in a power grid.

The AC-DC conversion circuit of this embodiment adopts a 220V to 5V conversion circuit, and the DC-DC conversion circuit adopts a 5V to 3.3V conversion circuit, and respectively stably outputs 5V and 3.3V DC voltages for DC power supply of the entire apparatus;

as shown in fig. 4, the AC-DC conversion circuit uses an AP9410 chip, and outputs a stable 5V DC voltage by continuously adjusting a transformer T1, and then by using an RC circuit formed by a capacitor C17 and a resistor R43 at ends of the

transformers

6 and 10, where the preferred value of the resistor R43 in this embodiment is 1K Ω;

as shown in fig. 5, the DC-DC conversion circuit converts 5V to 3.3V to supply power to the chip, the SPX1117M3-3.3 chip is used, the fuse F2 is a self-recovery fuse, and the output is automatically turned off when the circuit is short-circuited;

as shown in fig. 6, the main control board is provided with a power switch control pin PB5, a switch control pin PC6, a PC8, a PC7, a PC10, a switch detection pin PB12, another host switch detection pin PC4, a first external power-on key detection pin PC9, a second external power-on key detection pin PC11, and a buzzer control pin PC 3;

the main control board is respectively connected with the power switch circuit, the clock circuit, the optical coupling switch circuit, the USB interface circuit, the external key circuit and the switch time setting interface;

as shown in fig. 7, the power switching circuit includes: the LED driving circuit comprises a resistor R1, a resistor R2, a resistor R3, a triode Q1, a light emitting diode DS2, a diode D2, a direct current relay SLA-05VDC-SL-A, a resistor R38 and a capacitor C22;

one end of a light-emitting diode DS2 is connected with the output end of the AC-DC conversion circuit, the other end of the light-emitting diode DS2 is connected with one end of a resistor R1 and is connected with a collector of a triode Q1, one end of the resistor R2 is connected with a power switch control pin, the other end of a resistor R2 is connected with a base of a triode Q1, one end of a resistor R3 is connected with a base of a triode Q1, the other end of a resistor R3 is connected with an emitter of the triode Q1, and the emitter of the triode Q1 is grounded;

the resistor R38 is connected with the capacitor C22 in series, and after being connected in series, the whole is connected in parallel at two ends of a normally open contact of the direct current relay.

When the power switch control pin PB5 is at a high level, the base of an NPN triode Q1 connected with the resistor R2 is at a high level, the triode is conducted, the collector connected with the resistor R1 is at a low level, the relay U1 acts, the 4 pins, the 6 pins and the 2 pins of the relay are conducted, equipment is powered on, and the resistor R38 and the capacitor C22 are used for inhibiting contact arcs at the moment of switching; the power switch circuit of the embodiment outputs an alternating current power supply through the power output interface;

in this embodiment, the resistor R1 preferably has a value of 1K Ω, the resistor R2 preferably has a value of 2K Ω, the resistor R3 preferably has a value of 5.1K Ω, the resistor R38 preferably has a value of 330 ohms, the capacitor C22 preferably has a value of 2200pf, and the fuse F3 is a fuse with wire.

As shown in fig. 8, the clock circuit employs an RTC clock chip for time synchronization calibration.

As shown in fig. 9, the optocoupler switch circuit is provided with a solid-state relay CPC1017, the input end of the solid-state relay is connected with the on-off control pin of the main control board, the output end of the solid-state relay is connected with the on-off key of the computer, a plurality of solid-state relays can be arranged to be connected with the on-off keys of a plurality of computers, for example, wherein, the pins 3 and 4 of the solid-state relay U5 are connected with a computer startup key, when the main control board on-off control pin PC8 is at high level, the end of the resistor R4 is at high level, the solid state relay U5 is conducted, the 3 rd pin and the 4 th pin are connected at the moment, the computer is started by pressing the starting button, the switch wire of the computer does not need to be divided into the positive pole and the negative pole and is directly connected with the 3 rd pin and the 4 th pin, the output ends of other solid-state relays U6, U7 and U13 are connected with a computer startup key, a plurality of computer startup keys can be controlled independently, and the optical coupling switch circuit of the embodiment is further provided with an on-off signal output interface for outputting on-off signals.

In order to start the computer, two key pins for starting the computer need to be in short circuit, if one relay switch is adopted, the size is large, and the other relay switch is long-lived, in the embodiment, the CPC1017 is adopted as the solid-state switch, unlike the conventional method, when the PC8 is in a high level, the

pins

3 and 4 are conducted, the internal resistance is low at the moment, and the switching wire of the computer does not need to be divided into a positive electrode and a negative electrode and is directly connected to the

pins

3 and 4.

As shown in fig. 10, J3 in the USB interface circuit is a USB interface, which is connected to the computer, when the host is powered on, R31 is at a high level, at which time the transistor Q4 is turned on, and the main control board detects that the external power is at a high level through the switch detection pin PB 12;

the main control board is mutually connected with a computer through a USB through a series resistor of PA11 and PA12, a pin PA11 and a pin PA12 of a main control chip STM32 are simulated into a USB-HID interface and a computer end for communication according to a USB2.0 standard protocol, and the computer end is directly installed without being driven;

in this embodiment, the detection circuit is added with the low-resistance resistors of the first bleeder resistor R46, the second bleeder resistor R41 and the third bleeder resistor R16 as bleeder resistors, and the bleeder resistors are connected in parallel to form a bleeder circuit, so that the detection circuit is prevented from being interfered by other weak currents on other circuit boards and the influence of electricity of other circuits on the startup of the host computer is avoided under the condition that the host computer is not started, and the phenomenon that the host computer cannot be started up due to the fact that the host computer is powered up by the USB interface in reverse under the condition that the host computer is shut down. The USB-VCC is a power supply from the USB interface, when the computer is started, the USB-VCC is high level (has load capacity), the triode Q4 is conducted, the PB12 level changes, the main control board is considered as a starting state, otherwise, the main control board is considered as a state.

In this embodiment, the collector resistor R30 preferably has a value of 1.5k Ω, the base resistor R31 preferably has a value of 10k Ω, the emitter resistor R32 preferably has a value of 2k Ω, the ground resistor R33 preferably has a value of 5.1k Ω, the first bleeder resistor R46 preferably has a value of 680 Ω, the second bleeder resistor R41 preferably has a value of 680 Ω, and the third bleeder resistor R16 preferably has a value of 22 Ω;

as shown in fig. 11, the present embodiment is further provided with a USB electrostatic protection circuit, an anti-electrostatic IC of SRV05-4 is connected in parallel at the interface between pin PA11 and pin PA12 of the main control chip STM32, and plays a role in protection when there is static electricity;

as shown in fig. 12, the present embodiment is further provided with a USB detection circuit of another host, and the interface J10 is connected to the USB of the second computer host, so as to know the operation condition of the second computer;

because the second device only needs to detect the running condition and does not need communication, when the connected computer is started, the USB carries a point, at the moment, two ends of the resistor R40 are in high level, the main control jumps to high level through the detection pin PC4 of other host switches to consider that the connected computer is started, otherwise, the computer is shut down;

as shown in fig. 13, the first pin and the second pin in the four-pin slot J8 in the external key circuit, the third pin and the fourth pin are respectively connected to two external keys, when the keys of the third pin and the fourth pin are pressed, the resistor R29 is at a low level, the PNP transistor Q3 is tested to be turned on, and the main control chip STM32 detects that the external voltage is changed from the high level to the low level through the pin PC1, and knows that the keys are pressed.

As shown in fig. 14, the main control chip controls the conduction of the PNP transistor Q5 through the pin PC3 to control whether the buzzer B1 makes a sound for prompting when the device is turned on.

In this embodiment, the on-off time setting interface acquires the on-off time that sets up, can set up the switch every day, several switching on and shutting down every week or even several switching on and shutting down monthly, can set up multiunit time, carries out different settings to the holiday, more is favorable to the operation and the control of equipment.

In this embodiment, an implementation process of the specific operation of the on-off detection of the timing on-off device based on the USB interface is illustrated as follows:

the main control board reads the set time and the time of the clock chip and judges whether the set time is the starting time, if the set time is the starting time, the power switch control pin PB5 controls the power switch circuit to start the power supply of the timing startup and shutdown device;

whether a computer host is started up or not is detected through a power on/off detection pin PB12 in a J3 interface in a USB interface circuit, and the high level of a power on/off detection pin PB12 indicates the startup;

the solid-state relay U5 in the optical coupling switch circuit is conducted by controlling a power on/off control pin PC8, so that a computer power-on key connected to the output end of the solid-state relay U5 is conducted, and a first computer is powered on;

the method comprises the following steps that whether a computer host is started or not is detected through other host startup and shutdown detection pins PC4 in a J10 module in a USB interface circuit, and the high level of other host startup and shutdown detection pins PC4 indicates startup;

the solid-state relay U7 in the optical coupling switch circuit is conducted by controlling a power on/off control pin PC6, so that a computer power-on key connected to the output end of the solid-state relay U7 is conducted, and a second computer is powered on;

the main control board reads the set time and the time of the clock chip and judges whether the set time is the shutdown time;

whether the corresponding host is powered off is judged by judging the power on/off detection pin PB12 and the power on/off detection pin PC4 of other hosts, and the low level of the power on/off detection pin PB12 and the power on/off detection pin PC4 of other hosts indicates power off;

when the computer is not turned off, the corresponding optical coupling switch circuit is not conducted, the solid-state relay U5 corresponds to the first computer host, and the solid-state relay U7 corresponds to the second computer host;

after a certain period of time (e.g., 5 minutes), the power switch control pin PB5 goes low, and the power is turned off to stop the power supply to the entire device.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be equivalent replacement modes, and all are included in the scope of the present invention.

Claims

1. The utility model provides a time switch machine device based on USB interface is equipped with the main control board, its characterized in that still includes: the power supply comprises a power supply input interface, an EMI filter circuit, an EMC filter circuit, an AC-DC conversion circuit, a DC-DC conversion circuit, a power supply switch circuit, a clock circuit, an optical coupling switch circuit, a USB interface circuit and a switching time setting interface;

2. The timing switch device based on the USB interface of claim 1, wherein the USB interface circuit further includes a leakage circuit, the leakage circuit includes a first leakage resistor, a second leakage resistor and a third leakage resistor, the first leakage resistor, the second leakage resistor and the third leakage resistor are connected in parallel, one end of the first leakage resistor is connected to the USB power pin, and the other end of the first leakage resistor is connected to ground.

3. The USB interface-based timing switch device according to claim 1, further comprising a USB ESD protection circuit connected in parallel to the data transmission pin of the USB interface circuit.

4. The USB interface-based timing switch device according to claim 1, further comprising a USB detection circuit of another host, wherein the main control board is provided with a detection pin of the other host, the USB detection circuit of the other host comprises a USB power resistor and a ground resistor, one end of the USB power resistor is connected to a USB power source end, the other end of the USB power resistor is connected to one end of the ground resistor and to the detection pin of the other host of the main control board, and the other end of the ground resistor is grounded.

5. The USB interface-based timing switch device according to claim 1, further comprising an external key circuit, wherein the main control board comprises a first external power-on key detection pin and a second external power-on key detection pin;

6. The timing switch device based on the USB interface of claim 1, wherein the main control board is provided with a switch control pin, the optical coupling switch circuit is provided with a solid state relay, an input end of the solid state relay is connected with the switch control pin of the main control board, and an output end of the solid state relay is connected with a computer switch key.

7. The USB interface-based timing switch device according to claim 1, wherein the AC-DC conversion circuit is a conversion circuit from 220V AC to 5V DC, and the DC-DC conversion circuit is a conversion circuit from 5V DC to 3.3V DC.

8. The timing switch device based on USB interface of claim 1, wherein the main control board is provided with a power switch control pin, and the power switch circuit comprises: the LED driving circuit comprises a resistor R1, a resistor R2, a resistor R3, a triode Q1, a light emitting diode DS2, a diode D2, a direct current relay SLA-05VDC-SL-A, a resistor R38 and a capacitor C22;

9. The USB interface-based timing switch device according to claim 1, wherein the EMI filter circuit has an input terminal connected in series with the common mode inductor and connected in parallel with the differential mode filtering capacitor, and output terminals of the EMI filter circuit are provided with Y capacitors, one end of each Y capacitor is connected to one end of the output terminal, and the other end of each Y capacitor is connected to a ground line.

10. The timing switch device based on USB interface as claimed in claim 1, wherein said EMC filter circuit has its input connected in parallel with filtering differential mode capacitor and voltage dependent resistor, and in series with common mode inductor, and its output is provided with Y capacitor, one end of said Y capacitor is connected to one end of output, and the other end is connected to ground.