Universal serial bus (USB) interface expansion circuit based on handheld terminal equipment

Abstract

The invention relates to the technical field of USB (Universal Serial Bus) interface expansion, in particular to a USB interface expansion circuit based on handheld terminal equipment, which comprises a communication module, a power supply control unit, a first USB switch unit, a second USB switch unit, a PCIE (Peripheral Component Interface Express) to USB chip and an HUB chip, the first USB switch unit is respectively and electrically connected with a USB interface of the communication module, the second USB switch unit and a Type C interface on the handheld terminal equipment, the second USB switch unit is respectively and electrically connected with the PCIE-to-USB chip and the HUB chip, and the power supply control unit is respectively and electrically connected with a PCIE port of the communication module and the PCIE-to-USB chip, so that when the communication module with only one USB interface is selected, the communication module with only one USB interface is selected, and the communication module with only one USB interface is selected. A plurality of USB interfaces can be expanded, a full-function USB interface is provided, meanwhile, the power consumption of a product is not increased, and the cruising ability of the product is not reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of USB interface expansion, and particularly relates to a USB interface expansion circuit based on a handheld terminal device. Background Art

[0002] For handheld terminal devices, in most application scenarios or for most customers, there is a need to configure multiple USB interfaces for external communication with USB flash drives or USB devices. In the prior art, the following several methods are generally used to achieve this: (1) Directly use a CPU or communication module with two or more USB interfaces; (2) Use a CPU or communication module with one USB interface and combine it with a HUB chip to expand the USB interface; (3) Directly use a PCIE interface to expand the USB interface; However, the following problems exist in the above several methods: Method (1): Not all CPUs or communication modules are configured with two or more USB interfaces, resulting in limitations in solution selection; Method (2): Directly expanding with a HUB chip makes the USB interface of the CPU or communication module can only be used as a HOST interface (i.e., host interface), and cannot be used as a Device interface (i.e., slave interface), and the full function of the USB interface cannot be achieved; Method (3): Directly using a PCIE interface to expand the USB interface, due to the high power consumption of the PCIE to USB chip, the battery life of the handheld terminal device will be significantly reduced, bringing a poor experience to customers. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: to provide a USB interface expansion circuit based on a handheld terminal device, which can also expand multiple USB interfaces when a CPU or communication module with only one USB interface is selected, and has a full-function USB interface, while not increasing the power consumption of the product and not reducing the battery life of the product.

[0004] To solve the above technical problem, the technical solution adopted by the present invention is: A USB interface expansion circuit based on a handheld terminal device, comprising a communication module, a power control unit, a first USB switch unit, a second USB switch unit, a PCIE to USB chip, and a HUB chip. The communication module has one USB interface and one PCIE port; The USB interface of the communication module is electrically connected to the fixed end of the first USB switch unit. One moving end of the first USB switch unit is electrically connected to one moving end of the second USB switch unit. The other moving end of the first USB switch unit is used to be electrically connected to the Type-C interface on the handheld terminal device. The fixed end of the second USB switch unit is electrically connected to the input end of the HUB chip. The other moving end of the second USB switch unit is electrically connected to the output end of the PCIE to USB chip. The power control unit is respectively electrically connected to the PCIE port of the communication module and the input end of the PCIE to USB chip.

[0005] The beneficial effects of the present invention are as follows: In this solution, by setting a communication module, a power control unit, a first USB switch unit, a second USB switch unit, a PCIE to USB chip, and a HUB chip, the communication module has a USB interface and a PCIE port. The USB interface of the communication module is electrically connected to the fixed end of the first USB switch unit. One moving end of the first USB switch unit is electrically connected to one moving end of the second USB switch unit. The other moving end of the first USB switch unit is used to be electrically connected to the Type-C interface on the handheld terminal device. The fixed end of the second USB switch unit is electrically connected to the input end of the HUB chip. The other moving end of the second USB switch unit is electrically connected to the output end of the PCIE to USB chip. The power control unit is respectively electrically connected to the PCIE port of the communication module and the input end of the PCIE to USB chip. In this way, when the program is burned before the device leaves the factory, the USB interface of the communication module is directly connected to the Type-C interface of the device through the first USB switch unit, enabling the device to normally implement the program burning function. After the program is burned and the device is in the default boot state (when no USB device or adapter is connected to the Type-C interface at this time), the USB interface of the communication module is set as the host state. The USB interface of the communication module is connected to the HUB chip through the first USB switch unit and the second USB switch unit, realizing the expansion of the USB interface of the communication module. The power control unit does not power on the PCIE to USB chip, reducing the overall power consumption of the device and increasing the battery life of the device. When a USB device or adapter is connected to the Type-C interface, the power control unit powers on the PCIE to USB chip. The PCIE to USB chip is connected to the HUB chip through the second USB switch unit, realizing the expansion of the USB interface of the communication module. At the same time, the USB interface of the communication module is directly connected to the Type-C interface of the device through the first USB switch unit, thus realizing the full-function Type-C interface of the device. Therefore, when selecting a CPU or communication module with only one USB interface in this solution, not only can multiple USB interfaces be expanded, but also a full-function USB interface is available, while not increasing the power consumption of the product and not reducing the battery life of the product. Description of the Drawings

[0006] Figure 1 It is a connection block diagram of the USB interface expansion circuit based on a handheld terminal device of the present invention; Figure 2 It is a circuit schematic diagram of the first USB switch unit of the present invention; Figure 3 It is a circuit schematic diagram of the second USB switch unit of the present invention; Figure 4 It is a circuit schematic diagram of the power control unit of the present invention; Description of Reference Numerals: 1. Communication module; 2. Power control unit; 3. First USB switch unit; 4. Second USB switch unit; 5. PCIE to USB chip; 6. HUB chip. Specific Embodiments

[0007] To describe in detail the technical content, achieved objectives and effects of the present invention, the following is described in conjunction with the embodiments and with reference to the drawings.

[0008] Please refer to Figure 1 , a USB interface expansion circuit based on a handheld terminal device, comprising a communication module, a power control unit, a first USB switch unit, a second USB switch unit, a PCIE to USB chip, and a HUB chip. The communication module has a USB interface and a PCIE port; The USB interface of the communication module is electrically connected to the fixed end of the first USB switch unit. One moving end of the first USB switch unit is electrically connected to one moving end of the second USB switch unit. The other moving end of the first USB switch unit is used to be electrically connected to the Type C interface on the handheld terminal device. The fixed end of the second USB switch unit is electrically connected to the input end of the HUB chip. The other moving end of the second USB switch unit is electrically connected to the output end of the PCIE to USB chip. The power control unit is respectively electrically connected to the PCIE port of the communication module and the input end of the PCIE to USB chip.

[0009] From the above description, it can be seen that the beneficial effects of the present invention are as follows: This solution is achieved by setting up a communication module, a power control unit, a first USB switch unit, a second USB switch unit, a PCIE to USB chip, and a HUB chip. The communication module has a USB interface and a PCIE port. The USB interface of the communication module is electrically connected to the fixed end of the first USB switch unit. One moving end of the first USB switch unit is electrically connected to one moving end of the second USB switch unit. The other moving end of the first USB switch unit is used to be electrically connected to the Type C interface on the handheld terminal device. The fixed end of the second USB switch unit is electrically connected to the input end of the HUB chip. The other moving end of the second USB switch unit is electrically connected to the output end of the PCIE to USB chip. The power control unit is respectively electrically connected to the PCIE port of the communication module and the input end of the PCIE to USB chip. In this way, when the program is burned before the device leaves the factory, the USB interface of the communication module is directly connected to the Type C interface of the device through the first USB switch unit, enabling the device to normally implement the program burning function. After the program is burned and the device is in the default power-on state (when no USB device or adapter is connected to the Type C interface at this time), the USB interface of the communication module is set as the host state. The USB interface of the communication module is connected to the HUB chip through the first USB switch unit and the second USB switch unit, realizing the expansion of the USB interface of the communication module. The power control unit does not power on the PCIE to USB chip, reducing the overall power consumption of the device and increasing the battery life of the device. When a USB device or adapter is connected to the Type C interface, the power control unit powers on the PCIE to USB chip. The PCIE to USB chip is connected to the HUB chip through the second USB switch unit, realizing the expansion of the USB interface of the communication module. At the same time, the USB interface of the communication module is directly connected to the Type C interface of the device through the first USB switch unit, thus enabling the full-function Type C interface of the device. Therefore, when choosing a CPU or communication module with only one USB interface for this solution, it can not only expand multiple USB interfaces, but also have full-function USB interfaces, while not increasing the power consumption of the product and not reducing the battery life of the product.

[0010] Further, the first USB switch unit includes chip U60, the model of chip U60 is SGM7228. The third pin and the fifth pin of chip U60 are both electrically connected to the USB interface of the communication module. The sixth pin of chip U60 is electrically connected to one moving end of the second USB switch unit.

[0011] Further, the first USB switch unit further includes resistor R509 and resistor R513. One end of resistor R509 is respectively electrically connected to one end of resistor R513 and the tenth pin of chip U60. The other end of resistor R513 is grounded.

[0012] As can be seen from the above description, the resistor R509 is for convenient debugging and signal testing, etc.; the function of the resistor R513 is: when USB_SEL is in a high-impedance state, the SEL pin of the chip U60 is grounded.

[0013] Furthermore, the first USB switch unit further includes a resistor R512 and a capacitor C616. One end of the resistor R512 is electrically connected to the eighth pin of the chip U60. The other end of the resistor R512 is electrically connected to one end of the capacitor C616, and both the other end of the resistor R512 and one end of the capacitor C616 are grounded. The other end of the capacitor C616 is electrically connected to the ninth pin of the chip U60, and both the other end of the capacitor C616 and the ninth pin of the chip U60 are connected to a 3.3V power supply.

[0014] As can be seen from the above description, the resistor R512 grounds the OE pin of the chip U60 to enable the chip to work properly; the capacitor C616 filters the power supply terminal of the chip U60.

[0015] Furthermore, the second USB switch unit includes a chip U62. The model of the chip U62 is SGM7228. The first pin of the chip U62 is electrically connected to the output terminal of the PCIE to USB chip. The third pin and the fifth pin of the chip U62 are both electrically connected to the input terminal of the HUB chip. The sixth pin of the chip U62 is electrically connected to a moving terminal of the first USB switch unit.

[0016] Furthermore, the second USB switch unit further includes a resistor R544 and a resistor R546. One end of the resistor R544 is electrically connected to one end of the resistor R546 and the tenth pin of the chip U62 respectively. The other end of the resistor R546 is grounded.

[0017] As can be seen from the above description, the resistor R544 is for convenient debugging and signal testing, etc.; the function of the resistor R546 is: when USB_SEL is in a high-impedance state, the SEL pin of the chip U62 is grounded.

[0018] Furthermore, the second USB switch unit further includes a resistor R545 and a capacitor C632. One end of the resistor R545 is electrically connected to the eighth pin of the chip U62. The other end of the resistor R545 is electrically connected to one end of the capacitor C632, and both the other end of the resistor R545 and one end of the capacitor C632 are grounded. The other end of the capacitor C632 is electrically connected to the ninth pin of the chip U62, and both the other end of the capacitor C632 and the ninth pin of the chip U62 are connected to a power supply of a first preset voltage.

[0019] As can be seen from the above description, the resistor R545 grounds the OE pin of the chip U62 to enable the chip to work properly; the capacitor C632 filters the power supply terminal of the chip U62.

[0020] Further, the power supply control unit includes a chip U5, a triode Q7, and a MOS transistor Q8. The model of the chip U5 is SGM2037. The first pin of the chip U5 is electrically connected to the PCIE port of the communication module. The fourth pin of the chip U5 is electrically connected to the input end of the PCIE to USB chip. The source electrode of the MOS transistor Q8 is electrically connected to the PCIE port of the communication module. The gate electrode of the MOS transistor Q8 is electrically connected to the collector electrode of the triode Q7. The base electrode of the triode Q7 is electrically connected to the input end of the PCIE to USB chip. The emitter electrode of the triode Q7 is grounded.

[0021] As can be seen from the above description, when the PCIE_1V5_EN outputs a high level, the chip U5 works and outputs the 1.05V voltage required by the PCIE to USB chip. When the PCIE_1V5_EN outputs a low level, the chip U5 does not work and there is no 1.05V voltage output. When the PCIE_3V3_EN outputs a high level, the triode Q7 and the MOS transistor Q8 are turned on and output the 3.3V voltage required by the PCIE to USB chip. When the PCIE_3V3_EN outputs a low level, the triode Q7 and the MOS transistor Q8 are turned off and there is no 3.3V voltage output.

[0022] Further, the power supply control unit further includes a capacitor C45. One end of the capacitor C45 is grounded, and the other end of the capacitor C45 is electrically connected to the first pin of the chip U5 and the PCIE port of the communication module respectively.

[0023] As can be seen from the above description, the capacitor C45 is an energy storage and filtering capacitor for the chip power supply terminal.

[0024] Further, the power supply control unit further includes a resistor R43 and a capacitor C66. One end of the resistor R43 is electrically connected to the input end of the PCIE to USB chip. The other end of the resistor R43 is electrically connected to one end of the capacitor C66 and the fourth pin of the chip U5 respectively. The other end of the capacitor C66 is grounded.

[0025] As can be seen from the above description, the resistor R43 is for convenient debugging and signal testing, etc.

[0026] Please refer to Figures 1 to 4 As shown in the following, Embodiment 1 of the present invention is: Please refer to Figure 1, a USB interface expansion circuit based on a handheld terminal device, including a communication module 1, a power control unit 2, a first USB switch unit 3, a second USB switch unit 4, a PCIE to USB chip 5, and a HUB chip 6 arranged on the handheld terminal device. The communication module 1 has a USB interface and a PCIE port; The USB interface of the communication module 1 is electrically connected to the fixed end of the first USB switch unit 3. One moving end of the first USB switch unit 3 is electrically connected to one moving end of the second USB switch unit 4. The other moving end of the first USB switch unit 3 is used to be electrically connected to the Type C interface on the handheld terminal device. The fixed end of the second USB switch unit 4 is electrically connected to the input end of the HUB chip 6. The other moving end of the second USB switch unit 4 is electrically connected to the output end of the PCIE to USB chip 5. The power control unit 2 is respectively electrically connected to the PCIE port of the communication module 1 and the input end of the PCIE to USB chip 5.

[0027] Please refer to Figure 2 , the first USB switch unit 3 includes a chip U60. The model of the chip U60 is SGM7228. The third pin and the fifth pin of the chip U60 are both electrically connected to the USB interface of the communication module 1. The sixth pin of the chip U60 is electrically connected to one moving end of the second USB switch unit 4.

[0028] Please refer to Figure 2 , the first USB switch unit 3 further includes a resistor R509 and a resistor R513. One end of the resistor R509 is respectively electrically connected to one end of the resistor R513 and the tenth pin of the chip U60. The other end of the resistor R513 is grounded.

[0029] Please refer to Figure 2 , the first USB switch unit 3 further includes a resistor R512 and a capacitor C616. One end of the resistor R512 is electrically connected to the eighth pin of the chip U60. The other end of the resistor R512 is electrically connected to one end of the capacitor C616, and the other end of the resistor R512 and one end of the capacitor C616 are both grounded. The other end of the capacitor C616 is electrically connected to the ninth pin of the chip U60, and the other end of the capacitor C616 and the ninth pin of the chip U60 are both connected to the power supply of the first preset voltage (i.e., 3.3V).

[0030] Please refer to Figure 3, the second USB switch unit 4 includes a chip U62, the model of the chip U62 is SGM7228, the first pin of the chip U62 is electrically connected to the output end of the PCIE to USB chip 5, the third pin and the fifth pin of the chip U62 are both electrically connected to the input end of the HUB chip 6, and the sixth pin of the chip U62 is electrically connected to a moving end of the first USB switch unit 3.

[0031] Please refer to Figure 3 , the second USB switch unit 4 further includes a resistor R544 and a resistor R546. One end of the resistor R544 is electrically connected to one end of the resistor R546 and the tenth pin of the chip U62 respectively, and the other end of the resistor R546 is grounded.

[0032] Please refer to Figure 3 , the second USB switch unit 4 further includes a resistor R545 and a capacitor C632. One end of the resistor R545 is electrically connected to the eighth pin of the chip U62, the other end of the resistor R545 is electrically connected to one end of the capacitor C632 and both the other end of the resistor R545 and one end of the capacitor C632 are grounded, and the other end of the capacitor C632 is electrically connected to the ninth pin of the chip U62 and both the other end of the capacitor C632 and the ninth pin of the chip U62 are connected to the 3.3V power supply.

[0033] In this embodiment, the number of HUB chips 6 can be reasonably configured according to actual needs. If there are two HUB chips 6, one HUB chip 6 can have four USB interfaces, and one of the USB interfaces is electrically connected to the other HUB chip 6, so that four more USB interfaces can be expanded. The same applies to three HUB chips 6, four chips, and more HUB chips 6.

[0034] Please refer to Figure 4 , the power control unit 2 includes a chip U5, a triode Q7 and a MOS tube Q8. The model of the chip U5 is SGM2037. The first pin of the chip U5 is electrically connected to the PCIE port of the communication module 1. The fourth pin of the chip U5 is electrically connected to the input end of the PCIE to USB chip 5. The source electrode of the MOS tube Q8 is electrically connected to the PCIE port of the communication module 1. The gate electrode of the MOS tube Q8 is electrically connected to the collector electrode of the triode Q7. The base electrode of the triode Q7 is electrically connected to the input end of the PCIE to USB chip 5, and the emitter electrode of the triode Q7 is grounded.

[0035] Please refer to Figure 4 , the power control unit 2 further includes a capacitor C45. One end of the capacitor C45 is grounded, and the other end of the capacitor C45 is electrically connected to the first pin of the chip U5 and the PCIE port of the communication module 1 respectively.

[0036] Please refer to Figure 4 , the power control unit 2 further includes a resistor R43 and a capacitor C66. One end of the resistor R43 is electrically connected to the input end of the PCIE to USB chip 5, the other end of the resistor R43 is respectively electrically connected to one end of the capacitor C66 and the fourth pin of the chip U5, and the other end of the capacitor C66 is grounded.

[0037] The power control unit 2 further includes a capacitor C47, a resistor R41, a capacitor C68, a capacitor C61, a resistor R47, a capacitor C219, a resistor R244, a capacitor C213, a resistor R229, a capacitor C196, a capacitor C192, a resistor R238 and a resistor R218. For the specific connection relationship between its components, please refer to Figure 4 .

[0038] The working principle of the above USB interface expansion circuit based on a handheld terminal device is as follows: ① When the program is burned before the device leaves the factory, the control signal terminal USB_SEL of the chip U60 is connected to the IO port that outputs a low level by default when the communication module 1 is powered on. At this time, the third pin and the first pin of the chip U60 are conducted, and the fifth pin and the seventh pin of the chip U60 are conducted, so that the USB port of the communication module 1 is directly connected to the Type C interface of the device, enabling the device to normally implement the program burning function; ② After the program is burned and the device is in the default power-on state, the USB interface of the communication module 1 is in the host state, and the power supply enable pins PCIE_1V5_EN and PCIE_3V3_EN of the PCIE to USB chip 5 are set low, and the PCIE to USB chip 5 is not powered on, reducing the overall power consumption of the device and increasing the battery life of the device.

[0039] The control signal terminal USB_SEL of the chip U62 outputs a high level. At this time, the third pin and the second pin of the chip U62 are conducted, and the fifth pin and the seventh pin of the chip U62 are conducted, so that the USB interface of the communication module 1 is connected to the upstream port of the HUB chip 6, realizing the expansion of the USB interface of the communication module 1; ③ When the USB interface of the communication module 1 is in the host state, the CC signal is constantly in a flipped state to monitor whether a peripheral device is inserted into the Type-C interface of the monitoring device; when a Host device such as an adapter or a computer terminal is inserted, the CC pin will be pulled up, and the communication module 1 can recognize that a Host device is inserted; when a Device device such as a USB flash drive is inserted, the CC pin will be pulled down, and the communication module 1 can recognize that a Device device is inserted. Whether the communication module 1 recognizes that a Host device or a Device device is inserted, the control signal terminal USB_SEL of the chip U60 outputs a low level, enabling the USB port of the communication module 1 to be directly connected to the Type-C interface of the device, and at the same time releasing the USB configuration Host role. The actual role played is determined by the inserted peripheral device, realizing the full-function Type-C interface of the device.

[0040] The control signal terminal USB_SEL of the chip U62 outputs a low level, enabling the upstream port of the HUB chip 6 to be connected to the downstream port of the PCIE-to-USB chip 5. At the same time, the power supply enable pins PCIE_1V5_EN and PCIE_3V3_EN of the PCIE-to-USB chip 5 are set high, and the PCIE-to-USB chip 5 is powered on. The USB interface is expanded through the PCIE-to-USB chip 5, realizing the expansion of the device's USB interface.

[0041] In summary, a USB interface expansion circuit based on a handheld terminal device provided by the present invention includes a communication module, a power control unit, a first USB switch unit, a second USB switch unit, a PCIE-to-USB chip, and a HUB chip. The communication module has a USB interface and a PCIE port. The USB interface of the communication module is electrically connected to the fixed end of the first USB switch unit. One moving end of the first USB switch unit is electrically connected to one moving end of the second USB switch unit. The other moving end of the first USB switch unit is used to be electrically connected to the Type C interface on the handheld terminal device. The fixed end of the second USB switch unit is electrically connected to the input end of the HUB chip. The other moving end of the second USB switch unit is electrically connected to the output end of the PCIE-to-USB chip. The power control unit is respectively electrically connected to the PCIE port of the communication module and the input end of the PCIE-to-USB chip. In this way, when the device is not shipped and the program is burned, the USB interface of the communication module is directly connected to the Type C interface of the device through the first USB switch unit, enabling the device to normally implement the program burning function. After the program is burned and the device is in the default boot state (when no USB device or adapter is connected to the Type C interface at this time), the USB interface of the communication module is set to the host state. The USB interface of the communication module is connected to the HUB chip through the first USB switch unit and the second USB switch unit, realizing the expansion of the USB interface of the communication module. The power control unit does not power on the PCIE-to-USB chip, reducing the overall power consumption of the device and increasing the battery life of the device. When a USB device or adapter is connected to the Type C interface, the power control unit powers on the PCIE-to-USB chip. The PCIE-to-USB chip is connected to the HUB chip through the second USB switch unit, realizing the expansion of the USB interface of the communication module. At the same time, the USB interface of the communication module is directly connected to the Type C interface of the device through the first USB switch unit, thus realizing the full-function Type C interface of the device. Therefore, when a CPU or communication module with only one USB interface is selected in this solution, not only can multiple USB interfaces be expanded, but also a full-function USB interface is provided, while not increasing the power consumption of the product and not reducing the battery life of the product.

[0042] The above are only embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent transformation made using the content of the specification and drawings of the present invention, or directly or indirectly applied in related technical fields, shall be included in the patent protection scope of the present invention by the same token.

Claims

1. A USB interface expansion circuit based on a handheld terminal device, characterized in that, It includes a communication module, a power control unit, a first USB switch unit, a second USB switch unit, a PCIE to USB chip, and a HUB chip. The communication module has a USB interface and a PCIE port; The USB interface of the communication module is electrically connected to the fixed end of the first USB switch unit. One moving end of the first USB switch unit is electrically connected to one moving end of the second USB switch unit. The other moving end of the first USB switch unit is used to be electrically connected to the Type C interface on the handheld terminal device. The fixed end of the second USB switch unit is electrically connected to the input end of the HUB chip. The other moving end of the second USB switch unit is electrically connected to the output end of the PCIE to USB chip. The power control unit is respectively electrically connected to the PCIE port of the communication module and the input end of the PCIE to USB chip.

2. The USB interface expansion circuit based on a handheld terminal device according to claim 1, wherein The first USB switch unit includes chip U60. The model of chip U60 is SGM7228. The third pin and the fifth pin of chip U60 are both electrically connected to the USB interface of the communication module. The sixth pin of chip U60 is electrically connected to one moving end of the second USB switch unit.

3. The USB interface expansion circuit based on a handheld terminal device according to claim 2, wherein The first USB switch unit further includes resistor R509 and resistor R513. One end of resistor R509 is electrically connected to one end of resistor R513 and the tenth pin of chip U60 respectively. The other end of resistor R513 is grounded.

4. The USB interface expansion circuit based on a handheld terminal device according to claim 2, characterized in that The first USB switch unit further includes resistor R512 and capacitor C616. One end of resistor R512 is electrically connected to the eighth pin of chip U60. The other end of resistor R512 is electrically connected to one end of capacitor C616 and both the other end of resistor R512 and one end of capacitor C616 are grounded. The other end of capacitor C616 is electrically connected to the ninth pin of chip U60 and both the other end of capacitor C616 and the ninth pin of chip U60 are connected to the power supply of the first preset voltage.

5. The USB interface expansion circuit based on a handheld terminal device according to claim 1, characterized in that The second USB switch unit includes chip U62. The model of chip U62 is SGM7228. The first pin of chip U62 is electrically connected to the output end of the PCIE to USB chip. The third pin and the fifth pin of chip U62 are both electrically connected to the input end of the HUB chip. The sixth pin of chip U62 is electrically connected to one moving end of the first USB switch unit.

6. The USB interface expansion circuit based on a handheld terminal device according to claim 5, wherein The second USB switch unit further includes resistor R544 and resistor R546. One end of resistor R544 is electrically connected to one end of resistor R546 and the tenth pin of chip U62 respectively. The other end of resistor R546 is grounded.

7. The USB interface expansion circuit based on a handheld terminal device according to claim 5, characterized in that, The second USB switch unit further includes a resistor R545 and a capacitor C632. One end of the resistor R545 is electrically connected to the eighth pin of the chip U62. The other end of the resistor R545 is electrically connected to one end of the capacitor C632, and both the other end of the resistor R545 and one end of the capacitor C632 are grounded. The other end of the capacitor C632 is electrically connected to the ninth pin of the chip U62, and both the other end of the capacitor C632 and the ninth pin of the chip U62 are connected to a 3.3V power supply.

8. The USB interface expansion circuit based on a handheld terminal device according to claim 1, characterized in that The power supply control unit includes a chip U5, a triode Q7, and a MOS transistor Q8. The model of the chip U5 is SGM2037. The first pin of the chip U5 is electrically connected to the PCIE port of the communication module. The fourth pin of the chip U5 is electrically connected to the input end of the PCIE to USB chip. The source electrode of the MOS transistor Q8 is electrically connected to the PCIE port of the communication module. The gate electrode of the MOS transistor Q8 is electrically connected to the collector electrode of the triode Q7. The base electrode of the triode Q7 is electrically connected to the input end of the PCIE to USB chip. The emitter electrode of the triode Q7 is grounded.

9. The USB interface expansion circuit based on a handheld terminal device according to claim 8, characterized in that The power supply control unit further includes a capacitor C45. One end of the capacitor C45 is grounded. The other end of the capacitor C45 is electrically connected to the first pin of the chip U5 and the PCIE port of the communication module respectively.

10. The USB interface expansion circuit based on a handheld terminal device according to claim 8, wherein The power supply control unit further includes a resistor R43 and a capacitor C66. One end of the resistor R43 is electrically connected to the input end of the PCIE to USB chip. The other end of the resistor R43 is electrically connected to one end of the capacitor C66 and the fourth pin of the chip U5 respectively. The other end of the capacitor C66 is grounded.

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