Multifunctional USB data line circuit

Abstract

The utility model discloses a multifunctional USB (universal serial bus) data line circuit, which relates to the technical field of data lines and comprises a card reader chip U1, a storage unit, an indicator lamp circuit, a mode switching circuit, a USB Type A chip and a USB Type C chip. The card reader chip U1 is connected with the storage unit, the indicating lamp circuit, the mode switching circuit, the USB Type A chip and the USB Type C chip; the mode switching circuit is connected among the storage unit, the USB Type A chip and the USB Type C chip; and the indicating lamp circuit is connected with the mode switching circuit, the USB Type A chip and the USB Type C chip. The portable data line has the beneficial effects that the portability of the data line is ensured, and the user experience feeling is optimized.

Description

Technical Field

[0001] The utility model relates to the technical field of data lines, and more specifically to a multifunctional USB data line circuit. Background Art

[0002] The common mainstream USB3.1 Gen2 data cable is used to charge Type C devices or transmit data between Type C devices and computers. In addition, card readers are widely used in computers, mobile phones and other devices, with interfaces of USB Type C and USB Type A.

[0003] Data cables and card readers are commonly used electronic products and are indispensable main tool electronic products. However, traditional data cables do not have card reader functions, and card readers do not have traditional data cable functions. The two are independent products and are not convenient to carry. In addition, existing data cables with card reader functions mainly use manual switching functions, which are prone to misoperation and cannot achieve fully intelligent switching. Utility Model Content

[0004] In order to overcome the shortcomings of the prior art, the utility model provides a multifunctional USB data cable circuit, which effectively solves the problem that the traditional card reader and the data cable are inconvenient to carry due to the independent existence of the traditional card reader and the data cable and the existing data cable with card reader function is not intelligent enough, thereby ensuring the portability of the data cable and optimizing the user experience.

[0005] The technical solution adopted by the utility model to solve the technical problem is: a multifunctional USB data line circuit, the improvement of which is that the multifunctional USB data line circuit includes a card reader chip U1, a storage unit, an indicator light circuit, a mode switching circuit, a USB Type A chip and a USB Type C chip; the card reader chip U1 is connected with the storage unit, the indicator light circuit, the mode switching circuit, the USB Type A chip and the USB Type C chip; the mode switching circuit is connected between the storage unit, the USB Type A chip and the USB Type C chip; the indicator light circuit is connected with the mode switching circuit, the USB Type A chip and the USB Type C chip;

[0006] The mode switching circuit includes a first channel switching chip U9, a second channel switching chip U10, a third channel switching chip U11, a MOS tube Q3 and a triode Q4; the first channel switching chip U9, the second channel switching chip U10 and the third channel switching chip U11 are connected to each other; the gate of the MOS tube Q3 is connected to the collector of the triode Q4, the source is connected to the card reader chip U1, and the drain is connected to the first channel switching chip U9, the second channel switching chip U10 and the third channel switching chip U11; the base of the triode Q4 is grounded, and the emitter is connected to the second channel switching chip U10 and the third channel switching chip U11.

[0007] In the above structure, the mode switching circuit further includes a capacitor C17, a capacitor C31, a resistor R19, a resistor R20, a resistor R21 and a resistor R22; the positive electrode of the capacitor C17 is connected to one end of the resistor R21, the card reader chip U1 and the source of the MOS tube Q3, and the negative electrode is connected to one end of the resistor R22 and grounded; the positive electrode of the capacitor C31 is connected to the drain of the MOS tube Q3, and the negative electrode is grounded; the resistor R19 is connected between the gate of the MOS tube Q3 and the collector of the triode Q4; one end of the resistor R20 is connected to the gate of the MOS tube Q3, and the other end is grounded; the other end of the resistor R21 is connected to the other end of the resistor R22.

[0008] In the above structure, the storage unit includes a flash memory circuit and a read-only memory circuit, and both the flash memory circuit and the read-only memory circuit are connected to the card reader chip U1.

[0009] In the above structure, the flash memory circuit includes a flash memory chip U2, a resistor R6, a resistor R8 and a capacitor C19; the flash memory chip U1 includes a CS pin, a SO pin, a WP pin, a VSS pin, a VCC pin, a HOLD pin, a SCK pin and a SI pin; the CS pin, SO pin, SCK pin and SI pin of the flash memory chip U2 are connected to the card reader chip U1, the WP pin is connected to one end of the resistor R8, the VSS pin is grounded, the VCC pin is connected to a 3.3V voltage, and is connected to one end of the resistor R6 and the positive electrode of the capacitor C19, the HOLD pin is connected to the other end of the resistor R6; the other end of the resistor R8 is connected to a 3.3V voltage; the negative electrode of the capacitor C19 is grounded.

[0010] In the above structure, the read-only memory circuit includes a read-only memory chip U3 and a capacitor C27; the read-only memory chip U3 includes an AO pin, an A1 pin, an A2 pin, a GND pin, a VCC pin, a WC pin, an SCL pin and an SDA pin; the AO pin, A1 pin, A2 pin and GND pin of the read-only memory chip U3 are connected to the ground, the VCC pin is connected to the positive electrode of the capacitor C27, the WC pin is connected to the negative electrode of the capacitor C27, the SCL pin is connected to the SCK pin of the flash memory chip U2, and the SDA pin is connected to the SI pin of the flash memory chip U2.

[0011] In the above structure, the indicator light circuit includes a light-emitting diode D1, a light-emitting diode D2, a light-emitting diode D3, a resistor R10, a resistor R2 and a resistor R32; the anode of the light-emitting diode D1 is connected to one end of the resistor R10, and the cathode is grounded; the anode of the light-emitting diode D2 is connected to one end of the resistor R2, and the cathode is grounded; the anode of the light-emitting diode D3 is connected to one end of the resistor R32, and the cathode is grounded; the other end of the resistor R10 is connected to the card reader chip U1; the other end of the resistor R2 is connected to the USB Type A chip, the USB Type C chip and the emitter of the transistor Q4; the other end of the resistor R32 is connected to the SB Type A chip, the USB Type C chip and the base of the transistor Q4.

[0012] In the above structure, the multifunctional USB data line circuit also includes an SD socket circuit, which includes an SD socket and a capacitor C26; the positive electrode of the capacitor C26 is connected to the SD socket and the card reader chip U1, and the negative electrode is grounded; the SD socket and the card reader chip U1.

[0013] In the above structure, the multifunctional USB data line circuit also includes a voltage stabilizing circuit, which includes a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16 and a capacitor C20; the resistors R11, R12, R13, R14, R15 and R16 are connected between the card reader chip U1 and the SD socket; the positive electrode of the capacitor C20 is connected to the resistor R11, and the negative electrode is grounded.

[0014] In the above structure, the model of the card reader chip U1 is GL3224-QFN32.

[0015] In the above structure, the models of the first channel switch chip U9, the second channel switch chip U10 and the third channel switch chip U11 are all ASW3140.

[0016] The beneficial effects of the utility model are as follows: the scheme integrates a card reader chip, a USB Type A chip and a USB Type C chip into the same circuit structure, so that the circuit has both a card reader function and a data line function; a mode switching circuit switches a plurality of working modes of the data line, and an indicator light circuit indicates the working mode of the data line, so as to realize intelligent switching of the working mode of the data line, thereby ensuring the portability of the data line and optimizing the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a structural schematic diagram of a multifunctional USB data line circuit of the utility model;

[0018] Figure 2 This is a circuit connection diagram of a card reader chip U1 of a multifunctional USB data line circuit of the utility model;

[0019] Figure 3 This is a switching circuit connection diagram of a multifunctional USB data line circuit of the utility model;

[0020] Figure 4 This is a circuit connection diagram of a first channel switching chip U9 of a multifunctional USB data line circuit of the utility model;

[0021] Figure 5 This is a circuit connection diagram of a second channel switching chip U10 of a multifunctional USB data line circuit of the utility model;

[0022] Figure 6 This is a circuit connection diagram of a third channel switching chip U11 of a multifunctional USB data line circuit of the utility model;

[0023] Figure 7 This is a connection diagram of an indicator light circuit of a multifunctional USB data line circuit of the utility model;

[0024] Figure 8 This is a SD socket circuit connection diagram of a multifunctional USB data line circuit of the utility model;

[0025] Fig. 9 This is a voltage stabilizing circuit connection diagram of a multifunctional USB data line circuit of the utility model;

[0026] Fig.10 A flash memory circuit connection diagram of a multifunctional USB data line circuit of the utility model;

[0027] Fig.11 The utility model is a read-only storage circuit connection diagram of a multifunctional USB data line circuit. DETAILED DESCRIPTION

[0028] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0029] The following will clearly and completely describe the concept, specific structure and technical effects of the utility model in combination with the embodiments and drawings, so as to fully understand the purpose, characteristics and effects of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, other embodiments obtained by technicians in this field without creative work are all within the scope of protection of the utility model. In addition, all the connection / connection relationships involved in the patent do not refer to the direct connection of components, but refer to the formation of a better connection structure by adding or reducing connection accessories according to the specific implementation situation. The various technical features in the creation of the utility model can be combined interchangeably without conflicting with each other.

[0030] Reference Figure 1 As shown, the utility model discloses a multifunctional USB data line circuit, which includes a card reader chip U1, a storage unit, an indicator light circuit, a mode switching circuit, a USB Type A chip and a USB Type C chip; the card reader chip U1 is connected to the storage unit, the indicator light circuit, the mode switching circuit, the USB Type A chip and the USB Type C chip; the mode switching circuit is connected between the storage unit, the USB Type A chip and the USB Type C chip; the indicator light circuit is connected to the mode switching circuit, the USB Type A chip and the USB Type C chip; the model of the card reader chip U1 is GL3224-QFN32.

[0031] In this embodiment, the multifunctional USB data line circuit includes a card reader chip, a USB Type A chip, a USB Type C chip, a storage unit, a mode switching circuit and an indicator light circuit, wherein the card reader chip is connected to the USB Type A chip and the USB Type C chip for data transmission and power supply; the mode switching circuit is connected to the USB Type A chip and the USB Type C chip for detecting the connection status of the USB Type A chip and the USB Type C chip to switch the working mode of the data line; the indicator light circuit detects the output state of the mode switching circuit and indicates the corresponding working mode; the storage unit is used to store data read by the card reader chip U1, so as to transmit the data read by the card reader chip U1 to the connected device; when the utility model is specifically implemented, the multifunctional USB data line circuit integrates the card reader chip, the USB Type A chip and the USB Type C chip in the same circuit structure, so that the circuit has both the card reader function and the data line function; the data line is switched to multiple working modes by the mode switching circuit, and the working mode of the data line is indicated by the indicator light circuit, so as to realize the intelligent switching of the working mode of the data line, thereby ensuring the portability of the data line and optimizing the user experience.

[0032] Reference Figure 2-Figure 7As shown, the mode switching circuit includes a first channel switching chip U9, a second channel switching chip U10, a third channel switching chip U11, a MOS tube Q3, a triode Q4, a capacitor C17, a capacitor C31, a resistor R19, a resistor R20, a resistor R21 and a resistor R22; the first channel switching chip U9, the second channel switching chip U10 and the third channel switching chip U11 are connected to each other; the gate of the MOS tube Q3 is connected to the collector of the triode Q4, the source is connected to the card reader chip U1, and the drain is connected to the first channel switching chip U9, the second channel switching chip U10 and the third channel switching chip U11; the base of the triode Q4 is grounded, and the emitter is connected to the second channel switching chip U10 and the third channel switching chip U11; the positive electrode of the capacitor C17 is connected to one end of the resistor R21, the card reader chip U1 and the source of the MOS tube Q3, and the negative electrode is connected to one end of the resistor R22 and grounded; the The positive electrode is connected to the drain of the MOS tube Q3, and the negative electrode is grounded; the resistor R19 is connected between the gate of the MOS tube Q3 and the collector of the triode Q4; one end of the resistor R20 is connected to the gate of the MOS tube Q3, and the other end is grounded; the other end of the resistor R21 is connected to the other end of the resistor R22; the first channel switching chip U9, the second channel switching chip U10 and the third channel switching chip U11 are all ASW3140; the indicator light circuit includes a light-emitting diode D1, a light-emitting diode D2, a light-emitting diode D3, a resistor R10, a resistor R2 and a resistor R32; the anode of the light-emitting diode D1 is connected to one end of the resistor R10, and the cathode is grounded; the anode of the light-emitting diode D2 is connected to one end of the resistor R2, and the cathode is grounded; the anode of the light-emitting diode D3 is connected to one end of the resistor R32, and the cathode is grounded; the other end of the resistor R10 is connected to the card reader chip U1; the other end of the resistor R2 is connected to the USB The Type A chip, the USB Type C chip and the emitter of the transistor Q4 are connected; the other end of the resistor R32 is connected to the SB Type A chip, the USB Type C chip and the base of the transistor Q4.

[0033] In this embodiment, the card reader chip U1 is provided with 33 pins, the USB Type A chip is provided with 11 pins, the USB Type C chip is provided with 28 pins, the first channel switching chip U9, the second channel switching chip U10, and the third channel switching chip U11 are all provided with 19 pins, wherein the VBUS pin of the card reader chip U1 is connected to the source of the MOS tube Q3, and the LED pin of the card reader chip U1 is connected to the resistor R10; the DP pin of the card reader chip U1 is connected to the D+ pin of the USB Type A chip and the D+1 pin of the USB Type C chip; the DM pin of the card reader chip U1 is connected to the D- pin of the USB Type A chip and the D- pin of the USB Type The D-1 pin of the C chip is connected; the TXN pin, TXP pin, RXN pin and RXP pin of the card reader chip U1 are respectively connected to the A0- pin, A0+ pin, A1- pin and A1+ pin of the third channel switching chip U11; the C0- pin, C0+ pin, C1- pin and C1+ pin of the first channel switching chip U9 are respectively connected to the C0- pin, C0+ pin, C1- pin and C1+ pin of the second channel switching chip U10; the B0- The B0-, B0+, B1- and B1+ pins are connected to the B0-, B0+, B1- and B1+ pins of the third channel switching chip U11 respectively; the C0-, C0+, C1- and C1+ pins of the third channel switching chip U11 are connected to the B0-, B0+, B1- and B1+ pins of the first channel switching chip U9 respectively; the A0-, A0+, A1- and A1+ pins of the first channel switching chip U9 are connected to the USB The RX-pin, RX+pin, TX-pin and TX+pin of the Type A chip are connected; the A0-pin, A0+pin, A1-pin and A1+pin of the second channel switching chip U10 are respectively connected to the RX-pin, RX+pin, TX-pin and TX+pin of the USB Type C chip; the VDD pins of the first channel switching chip U9, the second channel switching chip U10 and the third channel switching chip U11 are all connected to the drain of the MOS tube Q3; the SEL pin of the second channel switching chip U10, the SEL pin of the third channel switching chip U11, the emitter of the transistor Q4, the VBUS pin of the USB Type A chip and the base of the transistor Q5 connected to the CC1 pin of the USB Type C chip are connected; the SEL pin of the first channel switching chip U9 is connected to the VBUS pin of the USB Type C chip;Through this circuit connection mode, when the utility model is specifically implemented, the multifunctional USB data line circuit can realize the switching of four working modes of the data line, wherein, working mode one and working mode two: the USB Type A chip is connected to the device, the USB_PW voltage is 5V; the USB Type C is also connected to the device, USB_GND is short-circuited with GND, the base of the transistor Q4 is grounded, the collector and emitter of the transistor Q4 are turned on, the gate of the MOS tube Q3 is at a high level, the drain and source of the MOS tube Q3 are disconnected, the source is the power supply of the card reader chip U1, and there is no voltage. At this time, the card reader chip U1 stops working, the light-emitting diode D1 is not bright, and the voltage of USB_PW and USB_C is 5V, and the light-emitting diodes D2 and D3 are bright; the USB Type C is connected to the device, USBC_SEL is short-circuited with USB_C, the USBC_SEL voltage is 5V, the collector and emitter of the transistor Q5 are turned on, the CC1 pin of the USBType C chip is grounded, and the USB Type C end is switched to charging and connecting with the USB Type The data transmission mode of end A; the voltage of SBC_SEL pin is 5V, the A end and C end of the first channel switching chip U9 are connected, and the A end and B end are disconnected; the USB_PW voltage is 5V, the A end and C end of the second channel switching chip U10 are connected, and the A end and B end are disconnected, and the A end and C end of the third channel switching chip U11 are connected, and the A end and B end are disconnected. The C end of the first channel switching chip U9 is connected to the C end of the second channel switching chip U10, and the A end (USB Type A) of the first channel switching chip U9 is connected to the A end (USB Type C) of the second channel switching chip U10; the A end of the first channel switching chip U9 is disconnected from the B end, and the A end of the second channel switching chip U10 is disconnected from the B end to avoid signal reflection, and USB Type A and USB Type C achieve high-speed transmission; working mode one and working mode two depend on whether the USB Type A end is connected to a power source or a device. When the power source is connected, working mode one is entered. If the device is connected, charging and data transmission can be performed at the same time; working mode three: USB Type A is connected to the device, USB_PW voltage is 5V, USB Type C is not connected to a device, USB_GND is disconnected from GND, the base of transistor Q4 is suspended, the emitter and collector are disconnected, the gate of MOS tube Q3 is pulled down to a low level by R20, the drain and source of MOS tube Q3 are turned on, the source (CR_VBUS) is the power supply of the card reader chip U1, and the CR_VBUS voltage is 5V. At this time, the card reader chip U1 works, the light-emitting diode D1 is on, and the voltage of USB_PW and USB_C is 5V, and the light-emitting diodes D2 and D3 are also on. Because USB Type C is not connected to a device, USBC_SEL is suspended, the A terminal and the B terminal of the first channel switching chip U9 are turned on, and the A terminal and the C terminal are disconnected;USB_PW voltage is 5V, the A end and C end of the third channel switch chip U11 are connected, and the A end and the B end are disconnected; because the USB Type C is not connected to the device, the A end of the second channel switch chip U10 is suspended, and the A end and the B end are disconnected; the B end of the first channel switch chip U9 is connected to the C end of the third channel switch chip U11, and the A end (USBType A) of the first channel switch chip U9 is connected to the A end (USB Type C) of the third channel switch chip U11; the A end and the B end of the first channel switch chip U9 are disconnected, and the A end and the B end of the third channel switch chip U11 are disconnected to avoid signal reflection, and the USB Type A and the card reader chip U1 achieve high-speed transmission; working mode four, the USB Type A chip is not connected to the device, and USB_PW is suspended; USB Type C is connected to the device, USB_GND is short-circuited with GND, the collector and emitter of transistor Q4 are turned on, but because USB_PW is suspended, the emitter of transistor Q4 has no voltage, the gate of MOS tube Q3 is pulled down to a low level by R20, the drain and source of MOS tube Q3 are turned on, the source (CR_VBUS) is the power supply of card reader chip U1, the voltage is 5V, at this time, the card reader chip U1 works, the light-emitting diode D1 is on, the voltage of USB_C is 5V, the light-emitting diode D3 is also on, and USB_PW is suspended, and the light-emitting diode D2 is not on; because USB_PW is suspended, the collector and emitter of transistor Q5 are disconnected, and the CC1 pin of USB Type C chip is pulled down with ground through resistor R18, and the USB Type C end switches to OTG mode, supplies power to the card reader chip U1, and transmits data with the card reader chip U1 normally; USB Type The USB Type A chip is connected to the device, USBC_SEL is short-circuited with USB_C, USBC_SEL voltage is 5V, the A end and C end of the first channel switch chip U9 are connected, and the A end and B end are disconnected; the USB Type A chip is not connected to the device, USB_PW is suspended, the A end and B end of the second channel switch chip U10 and the third channel switch chip U11 are connected, and the A end and C end are disconnected; the B end of the second channel switch chip U10 is connected to the B end of the third channel switch chip U11, and the A end (USB Type C) of the second channel switch chip U10 is connected to the A end (card reader chip U1) of the third channel switch chip U11; the A end and C end of the second channel switch chip U10 are disconnected, and the A end and C end of the third channel switch chip U11 are disconnected to avoid signal reflection, and the USB Type C chip and the card reader chip U1 achieve high-speed transmission. ;

[0034] Reference Figure 8-Figure 9As shown, the multifunctional USB data line circuit also includes an SD socket circuit, which includes an SD socket and a capacitor C26; the positive electrode of the capacitor C26 is connected to the SD socket and the card reader chip U1, and the negative electrode is grounded; the SD socket is connected to the card reader chip U1; the multifunctional USB data line circuit also includes a voltage stabilizing circuit, which includes a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16 and a capacitor C20; the resistor R11, the resistor R12, the resistor R13, the resistor R14, the resistor R15 and the resistor R16 are connected between the card reader chip U1 and the SD socket; the positive electrode of the capacitor C20 is connected to the resistor R11, and the negative electrode is grounded.

[0035] In this embodiment, the SD socket is provided with 19 pins, wherein the SDCLK ​​pin, SDDAT0 pin, SDDAT1 pin, SDDAT2 pin, SDDAT3 pin and SDCMD pin of the SD socket are respectively connected to the SD_CK pin, SD_D0 pin, SD_D1 pin, SD_D2 pin, SD_D3 pin and SD_CM pin of the card reader chip U1 through resistors R11, R12, R13, R14, R15 and R16; the SD_CDZ pin and SD_WP pin of the SD socket are respectively connected to the SD_CDZ pin and SD_WP pin of the card reader chip U1; the above circuit connection method is used to realize the control and data transmission of the SD socket; the existence of resistors R11, R12, R13, R14, R15 and R16 can ensure the stable power supply during data transmission.

[0036] Reference Figure 10-11As shown, the storage unit includes a flash memory circuit and a read-only storage circuit, and the flash memory circuit and the read-only storage circuit are both connected to the card reader chip U1; the flash memory circuit includes a flash memory chip U2, a resistor R6, a resistor R8 and a capacitor C19; the flash memory chip U1 includes a CS pin, an SO pin, a WP pin, a VSS pin, a VCC pin, a HOLD pin, a SCK pin and a SI pin; the CS pin, SO pin, SCK pin and SI pin of the flash memory chip U2 are connected to the card reader chip U1, the WP pin is connected to one end of the resistor R8, the VSS pin is grounded, the VCC pin is connected to a 3.3V voltage, and is connected to one end of the resistor R6 and the positive electrode of the capacitor C19, and the HOLD pin is connected to the positive electrode of the capacitor C19. The D pin is connected to the other end of the resistor R6; the other end of the resistor R8 is connected to a 3.3V voltage; the negative electrode of the capacitor C19 is grounded; the read-only memory circuit includes a read-only memory chip U3 and a capacitor C27; the read-only memory chip U3 includes an AO pin, an A1 pin, an A2 pin, a GND pin, a VCC pin, a WC pin, a SCL pin and a SDA pin; the AO pin, A1 pin, A2 pin and GND pin of the read-only memory chip U3 are connected to the ground, the VCC pin is connected to the positive electrode of the capacitor C27, the WC pin is connected to the negative electrode of the capacitor C27, the SCL pin is connected to the SCK pin of the flash memory chip U2, and the SDA pin is connected to the SI pin of the flash memory chip U2.

[0037] In this embodiment, the storage unit includes a flash memory circuit and a read-only storage circuit, wherein the flash memory circuit is used to provide a writable and erasable storage space for temporary or permanent data storage; the flash memory chip U2 communicates with the card reader chip U1 through the SO pin, the SCK pin and the SI pin, allowing the reading and writing of data stored in the flash memory chip U2; the resistor R6, the resistor R8 and the capacitor C19 ensure that the flash memory chip U2 works in the correct electrical environment, while the HOLD pin and the WP pin manage the status and permissions of the storage operation; the read-only storage circuit is used to provide a read-only storage function, such as storage device configuration information or firmware update, etc. The read-only storage chip U3 is connected to the flash memory chip U2 through a serial interface (SCL and SDA), allowing the reading of the data stored therein; the capacitor C27 is used for power management and stability; the presence of the storage unit enables the multi-function USB data cable to read and write different types of storage devices while ensuring the security and reliability of the data.

[0038] The above is a specific description of the preferred implementation of the utility model, but the invention of the utility model is not limited to the described embodiments. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the utility model. These equivalent deformations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A multifunctional USB data line circuit, characterized in that: The multifunctional USB data line circuit includes a card reader chip U1, a storage unit, an indicator light circuit, a mode switching circuit, a USB Type A chip, and a USB Type C chip; the card reader chip U1 is connected to the storage unit, the indicator light circuit, the mode switching circuit, the USB Type A chip, and the USB Type C chip; the mode switching circuit is connected between the storage unit, the USB Type A chip, and the USB Type C chip; the indicator light circuit is connected to the mode switching circuit, the USB Type A chip, and the USB Type C chip; The mode switching circuit includes a first channel switching chip U9, a second channel switching chip U10, a third channel switching chip U11, a MOS tube Q3 and a triode Q4; the first channel switching chip U9, the second channel switching chip U10 and the third channel switching chip U11 are connected to each other; the gate of the MOS tube Q3 is connected to the collector of the triode Q4, the source is connected to the card reader chip U1, and the drain is connected to the first channel switching chip U9, the second channel switching chip U10 and the third channel switching chip U11; the base of the triode Q4 is grounded, and the emitter is connected to the second channel switching chip U10 and the third channel switching chip U11.

2. A multifunctional USB data line circuit according to claim 1, characterized in that: The mode switching circuit also includes a capacitor C17, a capacitor C31, a resistor R19, a resistor R20, a resistor R21 and a resistor R22; the positive electrode of the capacitor C17 is connected to one end of the resistor R21, the card reader chip U1 and the source of the MOS tube Q3, and the negative electrode is connected to one end of the resistor R22 and grounded; the positive electrode of the capacitor C31 is connected to the drain of the MOS tube Q3, and the negative electrode is grounded; the resistor R19 is connected between the gate of the MOS tube Q3 and the collector of the triode Q4; one end of the resistor R20 is connected to the gate of the MOS tube Q3, and the other end is grounded; the other end of the resistor R21 is connected to the other end of the resistor R22.

3. A multifunctional USB data line circuit according to claim 1, characterized in that: The storage unit includes a flash memory circuit and a read-only memory circuit, and both the flash memory circuit and the read-only memory circuit are connected to the card reader chip U1.

4. A multifunctional USB data line circuit according to claim 3, characterized in that: The flash memory circuit includes a flash memory chip U2, a resistor R6, a resistor R8 and a capacitor C19; the flash memory chip U1 includes a CS pin, a SO pin, a WP pin, a VSS pin, a VCC pin, a HOLD pin, a SCK pin and a SI pin; the CS pin, SO pin, SCK pin and SI pin of the flash memory chip U2 are connected to the card reader chip U1, the WP pin is connected to one end of the resistor R8, the VSS pin is grounded, the VCC pin is connected to a 3.3V voltage, and is connected to one end of the resistor R6 and the positive electrode of the capacitor C19, the HOLD pin is connected to the other end of the resistor R6; the other end of the resistor R8 is connected to a 3.3V voltage; the negative electrode of the capacitor C19 is grounded.

5. A multifunctional USB data line circuit according to claim 4, characterized in that: The read-only memory circuit includes a read-only memory chip U3 and a capacitor C27; the read-only memory chip U3 includes an AO pin, an A1 pin, an A2 pin, a GND pin, a VCC pin, a WC pin, an SCL pin and an SDA pin; the AO pin, A1 pin, A2 pin and GND pin of the read-only memory chip U3 are connected to the ground, the VCC pin is connected to the positive electrode of the capacitor C27, the WC pin is connected to the negative electrode of the capacitor C27, the SCL pin is connected to the SCK pin of the flash memory chip U2, and the SDA pin is connected to the SI pin of the flash memory chip U2.

6. The multifunctional USB data line circuit according to claim 1, characterized in that: The indicator light circuit includes a light-emitting diode D1, a light-emitting diode D2, a light-emitting diode D3, a resistor R10, a resistor R2 and a resistor R32; the anode of the light-emitting diode D1 is connected to one end of the resistor R10, and the cathode is grounded; the anode of the light-emitting diode D2 is connected to one end of the resistor R2, and the cathode is grounded; the anode of the light-emitting diode D3 is connected to one end of the resistor R32, and the cathode is grounded; the other end of the resistor R10 is connected to the card reader chip U1; the other end of the resistor R2 is connected to the USB Type A chip, the USB Type C chip and the emitter of the transistor Q4; the other end of the resistor R32 is connected to the SB Type A chip, the USB Type C chip and the base of the transistor Q4.

7. The multifunctional USB data line circuit according to claim 1, characterized in that: The multifunctional USB data line circuit also includes an SD socket circuit, which includes an SD socket and a capacitor C26; the positive electrode of the capacitor C26 is connected to the SD socket and the card reader chip U1, and the negative electrode is grounded; the SD socket and the card reader chip U1.

8. A multifunctional USB data line circuit according to claim 7, characterized in that: The multifunctional USB data line circuit also includes a voltage stabilizing circuit, which includes a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16 and a capacitor C20; the resistors R11, R12, R13, R14, R15 and R16 are connected between the card reader chip U1 and the SD socket; the positive electrode of the capacitor C20 is connected to the resistor R11, and the negative electrode is grounded.

9. The multifunctional USB data line circuit according to claim 1, characterized in that: The model of the card reader chip U1 is GL3224-QFN32.

10. The multifunctional USB data line circuit according to claim 1, characterized in that: The models of the first channel switch chip U9, the second channel switch chip U10 and the third channel switch chip U11 are all ASW3140.

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