Circuit, method and apparatus for USB interface sharing

1. A circuit for Universal Serial Bus (USB) interface sharing, comprising: a host device module, a slave device module, a switch module and a USB interface, wherein a detection end of the host device module is connected to a signal detection end of the USB interface, a first control output end of the host device module is connected to a first control input end of the switch module, a data end of the host device module is connected to a first data end of the switch module, a data end of the slave device module is connected to a second data end of the switch module, and a third data end of the switch module is connected to a data end of the USB interface;

wherein the switch module further comprises a current limitation switch and a diode in parallel connection with the current limitation switch, a control input end of the current limitation switch serves as the second control input end of the switch module and is connected to the second control output end of the host device module, a power input end of the current limitation switch serves as the power input end of the switch module and is connected to the power supply of the terminal, a power output end of the current limitation switch serves as the power output end of the switch module and is connected to the power input end of the USB interface, an anode of the diode is connected to the power input end of the current limitation switch and a cathode of the diode is connected to the power output end of the current limitation switch;

when the type of the peripheral device is USB slave device, the host device module controls the current limitation switch of the switch module to be closed, such that a power supply of a terminal directly supplies power to the USB interface; and, when the type of the peripheral device is USB host device, the host device module controls the current limitation switch of the switch module to be opened, such that the power supply of the terminal supplies power to the USB interface via the diode.

2. The circuit for USB interface sharing as claimed in claim 1 , wherein the switch module comprises a USB signal switch, a control input end of the USB signal switch serves as the first control input end of the switch module and is connected to the first control output end of the host device module, a first end of the USB signal switch serves as the first data end of the switch module and is connected to the data end of the host device module, a second end of the USB signal switch serves as the second data end of the switch module and is connected to the data end of the slave device module, and a third end of the USB signal switch serves as the third data end of the switch module and is connected to the data end of the USB interface.

3. A method for Universal Serial Bus (USB) interface sharing implemented adopting the circuit for USB interface sharing as claimed in claim 1 , comprising:

detecting a USB signal, and judging a type of the peripheral device currently accessing the USB interface;

when the type of the peripheral device is USB host device, switching the USB signal switch of the switch module to the slave device module, and switching on a path between the slave device module and the USB interface; and

when the type of the peripheral device is USB slave device, switching the USB signal switch of the switch module to the host device module, and switching on a path between the host device module and the USB interface.

4. The method for USB interface sharing as claimed in claim 3 , wherein when the type of the peripheral device is USB host device, after switching the USB signal switch of the switch module to the slave device module and switching on the path between the slave device module and the USB interface, the method further comprises:

opening the current limitation switch of the switch module, such that the power supply of the terminal supplies power to the USB interface via the diode of the switch module.

5. The method for USB interface sharing as claimed in claim 3 , wherein when the type of the peripheral device is USB slave device, after switching the USB signal switch of the switch module to the host device module and switching on the path between the host device module and the USB interface, the method further comprises:

closing the current limitation switch of the switch module, such that the power supply of the terminal directly supplies power to the USB interface.

6. An apparatus for Universal Serial Bus (USB) interface sharing implemented adopting the circuit for USB interface sharing as claimed in claim 1 , comprising a host device module, a slave device module, a switch module and a USB interface, wherein

the host device module detects a USB signal and judges a type of the peripheral device currently accessing the USB interface; when the type of the peripheral device is USB host device, the host device module controls the switch module to switch on a path between the slave device module and the USB interface; and, when the type of the peripheral device is USB slave device, the host device module controls the switch module to switch on a path between the host device module and the USB interface.

7. The apparatus for USB interface sharing as claimed in claim 6 , wherein the switch module comprises a USB signal switch; when the type of the peripheral device is USB host device, the host device module controls the USB signal switch of the switch module to switch to the slave device module; and, when the type of the peripheral device is USB slave device, the host device module controls the USB signal switch of the switch module to switch to the host device module.

8. A method for Universal Serial Bus (USB) interface sharing implemented adopting the circuit for USB interface sharing as claimed in claim 2 , comprising:

detecting a USB signal, and judging a type of the peripheral device currently accessing the USB interface;

when the type of the peripheral device is USB host device, switching the USB signal switch of the switch module to the slave device module, and switching on a path between the slave device module and the USB interface; and

when the type of the peripheral device is USB slave device, switching the USB signal switch of the switch module to the host device module, and switching on a path between the host device module and the USB interface.

9. The method for USB interface sharing as claimed in claim 4 , wherein when the type of the peripheral device is USB slave device, after switching the USB signal switch of the switch module to the host device module and switching on the path between the host device module and the USB interface, the method further comprises:

closing the current limitation switch of the switch module, such that the power supply of the terminal directly supplies power to the USB interface.

10. An apparatus for Universal Serial Bus (USB) interface sharing implemented adopting the circuit for USB interface sharing as claimed in claim 2 , comprising a host device module, a slave device module, a switch module and a USB interface, wherein

the host device module detects a USB signal and judges a type of a peripheral device currently accessing the USB interface; when the type of the peripheral device is USB host device, the host device module controls the switch module to switch on a path between the slave device module and the USB interface; and, when the type of the peripheral device is USB slave device, the host device module controls the switch module to switch on a path between the host device module and the USB interface.