USB interface expansion circuit and device

Abstract

The utility model discloses a USB interface expansion circuit and a USB interface expansion device. The USB interface expansion circuit comprises a USB concentrator, a first switch module, a second switch module, a Type-C interface module and a plurality of USB interface modules, one end of the first switch module is used for being connected with a USB interface of a processor, and the other end of the first switch module is respectively connected with an upstream port of the USB hub and the Type-C interface module; a downstream port of the USB concentrator is respectively connected with the plurality of USB interface modules; one end of the second switch module is connected with the Type-C interface module, and the other end of the second switch module is used for being connected with a USB interface and a pull-down resistor of the processor. According to the utility model, the USB interface of the processor can be expanded, and the interface functions of the master and slave devices are provided at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of USB interfaces, and in particular to a USB interface expansion circuit and device. Background Art

[0002] Currently, handheld terminals typically require at least two USB (Universal Serial Bus) interfaces to connect to external USB flash drives or other USB devices for data transmission or communication. To address this, handheld terminals typically use processors with at least two USB interfaces to implement multiple interface configurations. However, not all processors with at least two USB interfaces are suitable for current handheld terminals. Therefore, this configuration limits the range of processors available for handheld terminals and has certain limitations.

[0003] Among them, for some processors with only one USB interface, a HUB can be used to expand one USB interface into multiple USB interfaces. However, this configuration method makes the processor's USB interface only a host interface and cannot be used as a device interface. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a USB interface expansion circuit and device, which can expand the USB interface of a processor and have the interface functions of a master and a slave device at the same time.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A USB interface expansion circuit includes a USB hub, a first switch module, a second switch module, a Type-C interface module, and multiple USB interface modules;

[0007] One end of the first switch module is used to connect to the USB interface of the processor, and the other end of the first switch module is respectively connected to the upstream port of the USB hub and the Type-C interface module;

[0008] The downstream ports of the USB hub are respectively connected to the multiple USB interface modules;

[0009] One end of the second switch module is connected to the Type-C interface module, and the other end of the second switch module is used to connect to the USB interface and the pull-down resistor of the processor respectively.

[0010] Furthermore, the first switch module includes a first switch chip, and the first switch chip includes a first control pin, a first common pin, a first selection pin, and a second selection pin;

[0011] The first control pin is used to connect to the driver port of the processor;

[0012] The first common pin is used to connect to the USB interface of the processor;

[0013] The first selection pin is connected to the Type-C interface module;

[0014] The second selection pin is connected to the upstream port of the USB hub.

[0015] Furthermore, the second switch module includes a second switch chip, and the second switch chip includes a second control pin, a second common pin, a third selection pin and a fourth selection pin;

[0016] The second control pin is used to connect to the driver port of the processor;

[0017] The second common pin is connected to the Type-C interface module;

[0018] The third selection pin is used to connect to the USB interface of the processor;

[0019] The fourth selection pin is connected to the pull-down resistor.

[0020] Furthermore, the first switch module further includes a dip switch;

[0021] One end of the dip switch is connected to the first control pin and the second control pin respectively, and the other end of the dip switch is grounded.

[0022] Furthermore, the first common pin is used to connect to a basic data transmission line of a USB interface of the processor.

[0023] Furthermore, the upstream port of the USB hub is also used to connect to a high-speed data transmission line of the USB interface of the processor.

[0024] Furthermore, the model of the USB hub is GL3523.

[0025] Furthermore, the model of the first switch chip and the second switch chip is SGM7228 or PI3USB10LP.

[0026] In order to solve the above technical problems, another technical solution adopted by the present invention is:

[0027] A USB interface expansion device includes the above-mentioned USB interface expansion circuit.

[0028] The utility model discloses a beneficial effect lies in: through the first switch module control processor's USB interface selects the connection type -C interface module or USB concentrator, thereby control processor is the interface extension or realizes master -slave equipment function. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The structure schematic drawing of a USB interface expansion circuit is provided for the utility model embodiment;

[0030] Figure 2 The pin schematic drawing of a type -C interface module is provided for the utility model embodiment;

[0031] Figure 3 The pin schematic drawing of a first switch chip is provided for the utility model embodiment;

[0032] Figure 4 The pin schematic drawing of a second switch chip is provided for the utility model embodiment;

[0033] Figure 5 The pin schematic drawing of a dial switch is provided for the utility model embodiment;

[0034] Figure 6 The pin schematic drawing of a USB concentrator is provided for the utility model embodiment;

[0035] Figure 7 The pin schematic drawing of a processor is provided for the utility model embodiment;

[0036] Label explanation:

[0037] 1, USB concentrator;2, first switch module;3, second switch module;4, type -C interface module;5, USB interface module;6, processor;7, pull -down resistance. DETAILED DESCRIPTION

[0038] To explain the technical content of the utility model, the purpose and effect realized in detail, the following is explained with the aid of the drawings by combining the embodiment.

[0039] An embodiment of the utility model provides a USB interface expansion circuit, comprising a USB hub, a first switch module, a second switch module, a Type-C interface module, and a plurality of USB interface modules;

[0040] One end of the first switch module is used to connect to the USB interface of the processor, and the other end of the first switch module is respectively connected to the upstream port of the USB hub and the Type-C interface module;

[0041] The downstream ports of the USB hub are respectively connected to the multiple USB interface modules;

[0042] One end of the second switch module is connected to the Type-C interface module, and the other end of the second switch module is used to connect to the USB interface and the pull-down resistor of the processor respectively.

[0043] As can be seen from the above description, the beneficial effect of the present invention is that: the first switch module controls the USB interface of the processor to select the connection to the Type-C interface module or the USB hub, thereby controlling the processor to perform interface expansion or realize the master-slave device function. When the first switch module chooses to connect to the Type-C interface module, the second switch module synchronously controls the Type-C interface module to select the connection to the USB interface of the processor, thereby controlling the processor to realize the master-slave device function. When the first switch module chooses to connect to the USB hub, the USB hub connects to multiple USB interface modules, realizing the expansion of the number of USB interfaces. At the same time, the second switch module chooses to connect the pull-down resistor, and the USB interface of the processor can only be used as a master device interface, and the device is in a powered state. In this way, the USB interface of the processor can be expanded and the interface function of the master and slave devices can be realized.

[0044] Furthermore, the first switch module includes a first switch chip, and the first switch chip includes a first control pin, a first common pin, a first selection pin, and a second selection pin;

[0045] The first control pin is used to connect to the driver port of the processor;

[0046] The first common pin is used to connect to the USB interface of the processor;

[0047] The first selection pin is connected to the Type-C interface module;

[0048] The second selection pin is connected to the upstream port of the USB hub.

[0049] As can be seen from the above description, in the first switch chip, the first control pin is used to control the first common pin to select whether to connect to the first selection pin or the second selection pin. When the processor needs to implement the slave device interface function, the driver port controls the first control pin so that the first common pin is connected to the first selection pin, thereby connecting the processor to the Type-C interface module. At this time, the USB interface of the processor can serve as a master device interface and a slave device interface. When the processor needs to implement the interface expansion function, the driver port controls the first control pin so that the first common pin is connected to the second selection pin, thereby connecting the processor to the USB hub. At this time, the USB interface of the processor can be connected to multiple USB interface modules.

[0050] Furthermore, the second switch module includes a second switch chip, and the second switch chip includes a second control pin, a second common pin, a third selection pin and a fourth selection pin;

[0051] The second control pin is used to connect to the driver port of the processor;

[0052] The second common pin is connected to the Type-C interface module;

[0053] The third selection pin is used to connect to the USB interface of the processor;

[0054] The fourth selection pin is connected to the pull-down resistor.

[0055] As can be seen from the above description, in the second switch chip, the second control pin is used to control whether the second common pin is connected to the third selection pin or the fourth selection pin. When the processor needs to implement the master-slave device interface function, the driver port controls the second control pin so that the second common pin is connected to the third selection pin, thereby connecting the processor to the Type-C interface module. When the processor needs to implement the interface expansion function, the driver port controls the second control pin so that the second common pin is connected to the fourth selection pin. At this time, the USB interface of the processor is connected to the pull-down resistor, so that the device is in a powered state.

[0056] Furthermore, the first switch module further includes a dip switch;

[0057] One end of the dip switch is connected to the first control pin and the second control pin respectively, and the other end of the dip switch is grounded.

[0058] As can be seen from the above description, the DIP switch is used to lock the USB interface function of the processor. When the DIP switch is in a specific state, the DIP switch is grounded, causing the first control pin and the second control pin to remain in a low state. At this time, the processor's USB interface is connected to the Type-C interface module to implement the master-slave device interface function. Regardless of the level state of the processor's driver port, the processor's USB interface is always connected to the Type-C interface, making it convenient for programmers to debug and burn the module.

[0059] Furthermore, the first common pin is used to connect to a basic data transmission line of a USB interface of the processor.

[0060] As can be seen from the above description, the USB hub is connected to the basic data transmission line of the USB interface of the processor, so that the USB interface resources are allocated through the USB hub, thereby realizing USB interface expansion.

[0061] Furthermore, the upstream port of the USB hub is also used to connect to a high-speed data transmission line of the USB interface of the processor.

[0062] As can be seen from the above description, the USB hub is connected to a high-speed data transmission line of the USB interface, so that the USB hub can be compatible with the ultra-high-speed transmission interface, namely USB 3.0, thereby improving the applicability of the USB interface.

[0063] Furthermore, the model of the USB hub is GL3523.

[0064] As can be seen from the above description, GL3523 has high compatibility and can support SuperSpeed, High-Speed ​​and Full-Speed ​​USB connections. It is also fully backward compatible with all USB2.0 connections, effectively ensuring the applicability of interface expansion.

[0065] Furthermore, the model of the first switch chip and the second switch chip is SGM7228 or PI3USB10LP.

[0066] From the above description, we can see that the SGM7228 or PI3USB10LP has low power consumption, which can effectively extend the battery life of the device. It also has a high transmission speed and is very suitable for switching high-speed USB2.0 signals.

[0067] Another embodiment of the present invention provides a USB interface expansion device, comprising the above-mentioned USB interface expansion circuit.

[0068] As can be seen from the above description, the beneficial effect of the present invention is that: the first switch module controls the USB interface of the processor to select the connection to the Type-C interface module or the USB hub, thereby controlling the processor to perform interface expansion or realize the master-slave device function. When the first switch module chooses to connect to the Type-C interface module, the second switch module synchronously controls the Type-C interface module to select the connection to the USB interface of the processor, thereby controlling the processor to realize the master-slave device function. When the first switch module chooses to connect to the USB hub, the USB hub connects to multiple USB interface modules, realizing the expansion of the number of USB interfaces. At the same time, the second switch module chooses to connect the pull-down resistor, and the USB interface of the processor can only be used as a master device interface, and the device is in a powered state. In this way, the USB interface of the processor can be expanded and the interface function of the master and slave devices can be realized.

[0069] The embodiments of the present invention provide a USB interface expansion circuit and device, which can be applied to a handheld terminal or electronic device, can expand the USB interface of the handheld terminal or electronic device, and simultaneously have the interface function of a master and a slave device. The following is an illustration of the present invention through specific embodiments:

[0070] Please refer to Figures 1 to 7 , the first embodiment of the present utility model is:

[0071] A USB interface expansion circuit includes a USB hub 1, a first switch module 2, a second switch module 3, a Type-C interface module 4 and multiple USB interface modules 5; Figure 1 As shown, specifically, one end of the first switch module 2 is used to connect to the USB interface of the processor 6, and the other end of the first switch module 2 is respectively connected to the upstream port of the USB hub 1 and the Type-C interface module 4; the downstream port of the USB hub 1 is respectively connected to multiple USB interface modules 5; one end of the second switch module 3 is connected to the Type-C interface module 4, and the other end of the second switch module 3 is respectively used to connect to the USB interface of the processor 6 and the pull-down resistor 7.

[0072] In some embodiments, the upstream port of the USB hub 1 is also used to connect to the high-speed data transmission lines of the USB interface of the processor 6, where the high-speed data transmission lines include SSTX and SSRX. The multiple USB interface modules are of different types. In this embodiment, the downstream port of the USB hub 1 can be extended to connect to four USB interface modules 5, two of which are USB 3.0 type and the other two are USB 2.0 type.

[0073] It should be noted that the upstream port of USB hub 1 refers to the port that connects USB hub 1 to the host, and there is usually only one port. It is responsible for allocating the host's USB interface resources to the hub so that the hub can further expand more USB interfaces. The downstream port of USB hub 1 refers to the port expanded by USB hub 1 for connecting multiple USB devices.

[0074] In some embodiments, the model of the USB hub 1 is GL3523; the model of the processor is SG530C.

[0075] like Figures 2 to 7 As shown, the following describes in detail a circuit structure of the USB hub 1, the first switch module 2, the second switch module 3, the Type-C interface module 4, and the multiple USB interface modules 5. In the following circuit structure, the USB hub 1, the Type-C interface module 4, and the processor 6 are represented by the USB hub U3, the Type-C interface module J1, and the processor U40C, respectively, to correspond to the components in the figure.

[0076] In some embodiments, the first switch module 2 includes a first switch chip U1. Specifically, the first switch chip U1 includes a first control pin, a first common pin, a first select pin, and a second select pin. The first control pin is used to connect to the driver port of the processor U40C, the first common pin is used to connect to the USB interface of the processor U40C, the first select pin is connected to the Type-C interface module J1, and the second select pin is connected to the upstream port of the USB hub U3. The first common pin is used to connect to the basic data transmission line of the USB interface of the processor U40C.

[0077] like Figure 2 and Figure 3As shown, the first control pin is pin 10 of the first switch chip U1, the driving port of the processor U40C is pin GPIO10, and pin 10 of the first switch chip U1 is connected to pin GPIO10 of the processor U40C. The first common pin is pin 3 and pin 5 of the first switch chip U1, the basic data transmission line of the USB interface is USB_DM and USB_DP, pin 3 of the first switch chip U1 is connected to USB_DP, and pin 5 of the first switch chip U1 is connected to USB_DM. The first selection pin is pin 1 and pin 7 of the first switch chip U1, pin 1 of the first switch chip U1 is connected to pin TYPEC_DP of the Type-C interface module J1, and pin 7 is connected to pin TYPEC_DM of the Type-C interface module J1. The second selection pin is pin 2 and pin 6 of the first switch chip U1, pin 2 of the first switch chip U1 is connected to pin HUB1_USB0_DP of the USB hub U3, and pin 6 of the first switch chip U1 is connected to pin HUB1_USB0_DM of the USB hub U3. Pin 8 and pin 9 of the first switch chip U1 are connected to the power supply circuit of the first switch chip U1, and pin 4 of the first switch chip U1 is grounded.

[0078] The working principle of the first switch chip U1 is as follows: when the driving port GPIO10 of the processor U40C outputs a low-level signal, that is, the pin 10 of the first switch chip U1 receives a low-level signal, the first common pin of the first switch chip U1 is connected to the first selection pin, specifically, the first switch chip U1 connects its pin 3 with its pin 1 and connects its pin 5 with its pin 7. When the driving port GPIO10 of the processor U40C outputs a high-level signal, that is, the pin 10 of the first switch chip U1 receives a high-level signal, the first common pin of the first switch chip U1 is connected to the second selection pin, specifically, the first switch chip U1 connects its pin 3 with its pin 2 and connects its pin 5 with its pin 6.

[0079] In some embodiments, the second switch module 3 includes a second switch chip U2; specifically, the second switch chip U2 includes a second control pin, a second common pin, a third selection pin and a fourth selection pin; the second control pin is used to connect the driving port of the processor U40C, the second common pin is connected to the Type-C interface module J1, the third selection pin is used to connect the USB interface of the processor U40C, and the fourth selection pin is connected to a pull-down resistor. The third selection pin is used to connect the device configuration transmission line of the USB interface of the processor U40C.

[0080] As Figure 2 and Figure 4As shown, the second control pin is pin 10 of the second switch chip U2, which is connected to pin GPIO10 of the processor U40C. The second common pins are pins 3 and 5 of the second switch chip U2. Pin 3 of the second switch chip U2 is connected to pin USB_CC1 of the Type-C interface module J1, and pin 5 of the second switch chip U2 is connected to pin USB_CC2 of the Type-C interface module J1. The third selection pins are pins 1 and 7 of the second switch chip U2. The device configuration transmission lines of the USB interface include USB_CCA and USB_CCB. Pin 1 of the second switch chip U2 is connected to USB_CCB, and pin 7 is connected to USB_CCA. The fourth selection pins are pins 2 and 6 of the second switch chip U2. Pin 2 of the second switch chip U2 is connected to pull-down resistor R8, and pin 6 of the second switch chip U2 is connected to pull-down resistor R1. Pins 8 and 9 of the second switch chip U2 are connected to the power supply circuit of the second switch chip U2, and pin 4 of the second switch chip U2 is grounded.

[0081] The operating principle of the second switch chip U2 is the same as that of the first switch chip U1 and will not be repeated here. When the first common pin of the second switch chip U2 is connected to the fourth selection pin, the USBCC1 / CC2 of the Type-C interface are connected to the pull-down resistor. The processor's USB interface can only function as a master device interface. When a PD adapter is inserted, the device is in charging state.

[0082] It should be noted that Figure 3 and Figure 4 In the figure, 0402 on the resistor indicates the package size of the resistor, the resistance of the pull-down resistor R1 and the resistor R8 are both 5.1K, and 1% indicates the resistance accuracy.

[0083] In some embodiments, the first switch module 2 further includes a dip switch J2; one end of the dip switch J2 is connected to the first control pin and the second control pin respectively, and the other end of the dip switch J2 is grounded.

[0084] like Figure 5As shown, pin 1 of the dip switch J2, namely the USBID_SET pin, is connected to pin 10 of the first switch chip U1 and pin 10 of the second switch chip U2, respectively. Pin 4 of the dip switch J2 is grounded. The dip switch J2 includes an ON position and an OFF position. When the dip switch J2 is in the ON position, pin 1 of the dip switch J2 is connected to pin 4, causing the USBID_SET pin to be grounded and outputting a low-level signal. When the dip switch J2 is in the OFF position, pin 1 of the dip switch J2 is disconnected from pin 4. At this time, the level states of pins 10 of the first switch chip U1 and pin 10 of the second switch chip U2 are controlled by pin GPIO10 of the processor U40C. In this way, when the dip switch J2 is in the ON position, regardless of whether the driver port GPIO10 of the processor U40C outputs a high-level signal or a low-level signal, pins 10 of the first switch chip U1 and pin 10 of the second switch chip U2 receive a low-level signal.

[0085] In some embodiments, the first switch chip U1 and the second switch chip U2 are of the model SGM7228 or PI3USB10LP.

[0086] like Figure 6 As shown, pins 72, 71, 69, and 68 of the USB hub U3 are connected to the high-speed data transmission lines AP_SSTX1_P, AP_SSTX1_N, AP_SSRX1_P, and AP_SSRX1_N of the processor U40C, respectively. Pins 66 and 67 of the USB hub U3 are connected to pins 6 and 2 of the first switch module, namely HUB1_USB0_DM and HUB1_USB0_DP. The downstream ports of USB hub U3 include HUB1_USB1_DM / DP (pins 64 and 63), HUB1_USB2_DM / DP (pins 26 and 25), HUB1_USB2_SSTXN / P (pins 20 and 21), HUB1_USB2_SSRXN / P (pins 23 and 24), HUB1_USB3_DM / DP (pins 13 and 14), HUB1_USB3_SSTXN / P (pins 15 and 16), HUB1_USB3_SSRXN / P (pins 18 and 19), and HUB1_USB4_DM / DP (pins 10 and 11). Among them, pin 72, pin 71, pin 69, pin 68 and HUB1_USB0 are the upstream ports of the USB hub U3; HUB1_USB1-4 are the downstream ports of the USB hub U3, HUB1_USB1 and HUB1_USB4 are used to connect to the USB2.0 interface module, and HUB1_USB2 and HUB1_USB3 are used to connect to the USB3.0 interface module.

[0087] like Figure 7 As shown, pins 354 and 358 of processor U40C are basic data transmission lines, namely USB_DP and USB_DM. Pins 356, 353, 360, and 357 of processor U40C are high-speed data transmission lines, namely AP_SSTX1_P, AP_SSTX1_N, AP_SSRX1_P, and AP_SSRX1_N. Pins 339 and 342 of processor U40C are device configuration transmission lines, namely USB_CCA and USB_CCB.

[0088] The working principle of a USB interface expansion circuit of the utility model is specifically as follows:

[0089] When the processor's driver port outputs a low-level signal, the first common pin of the first switch chip is connected to the first selection pin, connecting the DP / DM pins of the processor's USB interface to the DP / DM pins of the Type-C interface module. Simultaneously, the second common pin of the second switch chip is connected to the third selection pin, connecting the CCA / CCB pins of the processor's USB interface to the CC1 / CC2 pins of the Type-C interface module. This directly connects the processor's USB interface to the Type-C interface module, allowing the processor's USB interface to function as both a host and a device.

[0090] When debugging or programming a handheld device, the processor's USB port must always function as a device port. Therefore, manually set the DIP switch to the ON position, grounding the first control pin of the first switch chip and the second control pin of the second switch chip. At this point, regardless of whether the processor's driver port outputs a high or low level, the processor's USB port remains directly connected to the Type-C interface module. After debugging or programming the handheld device, manually set the DIP switch to the OFF position to unlock it.

[0091] When the processor's driver port outputs a high-level signal, the first common pin of the first switch chip is controlled to connect to the second select pin, connecting the DP / DM of the processor's USB interface to the DP / DM of the USB hub. This means that the processor's USB interface is extended to four USB interface modules via the USB hub, with the processor's USB interface acting as a host port. Simultaneously, the second common pin of the second switch chip is controlled to connect to the fourth select pin, connecting CC1 / CC2 of the Type-C interface module to a pull-down resistor. According to the PD protocol, when a PD adapter is inserted, the VBUS of the PD adapter outputs 5V through the Type-C interface module to power the handheld device.

[0092] The second embodiment of the present invention is:

[0093] A USB interface expansion device includes the USB interface expansion circuit described in the first embodiment.

[0094] In summary, the utility model provides a USB interface expansion circuit and device, which controls the USB interface of the processor to connect to the Type-C interface module or the USB hub through the first switch module. When the first switch module chooses to connect to the Type-C interface module, the second switch module is used to control the Type-C interface module to choose to connect to the USB interface of the processor, so that the USB interface of the processor is directly connected to the Type-C interface module, thereby ensuring that the USB interface of the processor can be used as both a host interface and a device interface. At the same time, in order to ensure the stability of the USB interface during debugging and burning, the selection status of the first switch module and the second switch module is locked by the dip switch. When the first switch module chooses to connect to the USB hub, multiple USB interface modules are connected through the USB hub to expand the number of USB interfaces. At the same time, the second switch module is used to control the Type-C interface module to connect to the pull-down resistor, and the USB interface of the processor can only be used as the master device interface to complete power supply. In this way, the USB interface of the processor can be expanded and the interface function of the master and slave devices can be realized.

[0095] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the description and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A USB interface expansion circuit, characterized in that: It includes a USB hub, a first switch module, a second switch module, a Type-C interface module, and multiple USB interface modules; One end of the first switch module is used to connect to the USB interface of the processor, and the other end of the first switch module is respectively connected to the upstream port of the USB hub and the Type-C interface module; The downstream ports of the USB hub are respectively connected to the multiple USB interface modules; One end of the second switch module is connected to the Type-C interface module, and the other end of the second switch module is used to connect to the USB interface and the pull-down resistor of the processor respectively.

2. A USB interface expansion circuit according to claim 1, characterized in that: The first switch module includes a first switch chip, and the first switch chip includes a first control pin, a first common pin, a first selection pin and a second selection pin; The first control pin is used to connect to the driver port of the processor; The first common pin is used to connect to the USB interface of the processor; The first selection pin is connected to the Type-C interface module; The second selection pin is connected to the upstream port of the USB hub.

3. A USB interface expansion circuit according to claim 2, characterized in that: The second switch module includes a second switch chip, and the second switch chip includes a second control pin, a second common pin, a third selection pin and a fourth selection pin; The second control pin is used to connect to the driver port of the processor; The second common pin is connected to the Type-C interface module; The third selection pin is used to connect to the USB interface of the processor; The fourth selection pin is connected to the pull-down resistor.

4. A USB interface expansion circuit according to claim 3, characterized in that: The first switch module further includes a dip switch; One end of the dip switch is connected to the first control pin and the second control pin respectively, and the other end of the dip switch is grounded.

5. The USB interface expansion circuit according to claim 2, wherein: The first common pin is used to connect to a basic data transmission line of a USB interface of the processor.

6. The USB interface expansion circuit according to claim 1, characterized in that: The upstream port of the USB hub is also used to connect to the high-speed data transmission line of the USB interface of the processor.

7. The USB interface expansion circuit according to claim 6, characterized in that: The model of the USB hub is GL3523.

8. The USB interface expansion circuit according to claim 3, characterized in that: The models of the first switch chip and the second switch chip are SGM7228 or PI3USB10LP.

9. A USB interface expansion device, characterized in that: The invention comprises a USB interface expansion circuit as described in any one of claims 1 to 8.

Images