A signal transmission circuit based on USB interface

Abstract

The utility model relates to circuit technical field especially, it relates to a signal transmission circuit based on USB interface, include: total power supply connecting end, secondary power supply connecting end, tertiary power supply connecting end, equipment connecting end, computer connecting end, crystal oscillator, power control module, analog switch module, wherein, power control module is connected with total power supply connecting end, secondary power supply connecting end, tertiary power supply connecting end, crystal oscillator, analog switch module respectively, analog switch module still is connected with tertiary power supply connecting end, equipment connecting end, computer connecting end respectively. Through the combination power management function and USB HUB signal enhancement function have realized " equipment direct connection computer " and " through HUB relay connection " two modes between switching, to solve the attenuation problem and HUB compatibility problem of USB signal long distance transmission.

Description

Technical Field

[0001] This utility model relates to the field of circuit technology, and in particular to a signal transmission circuit based on a USB interface. Background Technology

[0002] As the primary medium for data transmission, USB cables present dual challenges of long-distance transmission and system compatibility due to their physical limitations. The standard USB transmission distance is typically no more than 5 meters. During long-distance transmission, high-frequency signals suffer severe attenuation due to cable impedance, capacitance, and electromagnetic interference, leading to signal waveform distortion, increased timing jitter, and ultimately communication failure or a sharp drop in speed. Using a USB hub chip for signal shaping and driving is the mainstream solution to overcome distance limitations, but it introduces new problems, namely, some computers have poor compatibility with specific hub chips, causing devices to be unrecognized when connected to the hub. Utility Model Content

[0003] This invention provides a signal transmission circuit based on a USB interface to solve the defects of signal attenuation and low HUB compatibility in the prior art during long-distance USB transmission, thereby achieving enhanced signal strength and high HUB compatibility in complex environments during long-distance transmission.

[0004] This utility model provides a signal transmission circuit based on a USB interface, including: a main power connection terminal, a secondary power connection terminal, a tertiary power connection terminal, a device connection terminal, a computer connection terminal, a crystal oscillator, a power control module, and an analog switching module;

[0005] The power control module is connected to the main power supply terminal, the secondary power supply terminal, the tertiary power supply terminal, the crystal oscillator, and the analog switching module. The analog switching module is also connected to the tertiary power supply terminal, the device terminal, and the computer terminal.

[0006] According to the present invention, a signal transmission circuit based on a USB interface is provided, wherein the power control module includes: a USB port power switch chip, an LDO power chip, and a USB-HUB chip.

[0007] The USB port power switch chip has six pins: the VIN pin is connected to the main power supply terminal, the ISET pin is grounded through a second resistor, the EN pin is connected to the main power supply terminal through a first resistor, the FLAG pin is connected to the USB-HUB chip, the GND pin is grounded, the VOUT pin is connected to the LDO power chip, and the VOUT pin of the USB port power switch chip is also connected to the secondary power supply terminal.

[0008] According to the present invention, a signal transmission circuit based on a USB interface is provided. The LDO power chip has five pins. Its IN pin is connected to the secondary power supply terminal, the GND pin is grounded, the EN pin is connected to the secondary power supply terminal through a third resistor, the BP pin is grounded through a third capacitor, and the OUT pin is connected to the tertiary power supply terminal. The OUT pin of the LDO power chip is also connected to the USB-HUB chip.

[0009] According to the present invention, a signal transmission circuit based on a USB interface is provided, wherein the VDD33 pin and 5V pin of the USB-HUB chip are connected to the three-level power supply connection terminal, the GND pin is grounded, the OVCUR pin is connected to the FLAG pin of the USB port power switch chip, the XO pin and XI pin are respectively connected to the crystal oscillator, and the DPU pin, DMU pin, DM1 pin and DP1 pin are respectively connected to the analog switching module.

[0010] According to the signal transmission circuit based on the USB interface provided by this utility model, the VDD33 pin of the USB-HUB chip is also grounded through the fifth capacitor, the 5V pin is also grounded through the sixth capacitor, and the OVCUR pin is also connected to the three-level power supply connection terminal through the fourth resistor.

[0011] According to the present invention, a signal transmission circuit based on a USB interface is provided, wherein the crystal oscillator has four pins, the GND pin is grounded, the X1 pin is connected to the XI pin of the USB-HUB chip, and the X2 pin is connected to the XO pin of the USB-HUB chip.

[0012] According to the present invention, a signal transmission circuit based on a USB interface is provided, wherein the analog switching module includes: a first analog switching switch and a second analog switching switch;

[0013] The first analog switch has ten pins: its S pin is connected to the device connection terminal, its HSD2+ pin is connected to the DM1 pin of the USB-HUB chip, its GND pin is grounded, its V+ pin is connected to the three-level power supply connection terminal, its OE pin is grounded through the sixth resistor, its HSD2- pin is connected to the DP1 pin of the USB-HUB chip, its HSD1+ and HSD1- pins are both floating, and its D+ and D- pins are respectively connected to the second analog switch.

[0014] According to the signal transmission circuit based on the USB interface provided by this utility model, the S pin of the first analog switch is also grounded through the fifth resistor, and the V+ pin is also grounded through the ninth capacitor.

[0015] According to the present invention, a signal transmission circuit based on a USB interface is provided, wherein the second analog switch has ten pins, the S pin of which is connected to the S pin of the first analog switch, the HSD1+ pin is connected to the D+ pin of the first analog switch, the HSD2+ pin is connected to the DPU pin of the USB-HUB chip, the D+ pin and the D- pin are both connected to the computer connection terminal, the GND pin is grounded, the V+ pin is connected to the three-level power supply connection terminal, the OE pin is grounded through the seventh resistor, the HSD1- pin is connected to the D- pin of the first analog switch, and the HSD2- pin is connected to the DMU pin of the USB-HUB chip.

[0016] According to the signal transmission circuit based on the USB interface provided by this utility model, the V+ pin of the second analog switching switch is also grounded through the tenth capacitor.

[0017] This utility model provides a signal transmission circuit based on a USB interface. By combining the power management function (USB port power switch chip U1, LDO power chip U2) and the USB HUB signal enhancement function (USB-HUB chip U3), it realizes the switching between two modes: "direct connection of device to computer" and "connection via HUB relay", so as to solve the problem of attenuation of USB signal transmission over long distances and the HUB compatibility problem. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is an electrical block diagram of a signal transmission circuit based on a USB interface provided by this utility model;

[0020] Figure 2 This is one of the circuit diagrams of a signal transmission circuit based on a USB interface provided by this utility model;

[0021] Figure 3 This is the second circuit diagram of a signal transmission circuit based on a USB interface provided by this utility model;

[0022] Figure 4 This is a diagram illustrating the direct connection between the device and the computer when the device connection terminal outputs a low-level signal.

[0023] Figure 5 This is a schematic diagram showing the connection between the device, the USB-HUB chip, and the computer when the device connection terminal outputs a high-level signal. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0025] The following is combined Figures 1-5 This utility model describes a signal transmission circuit based on a USB interface, comprising: a main power connection terminal, a secondary power connection terminal, a tertiary power connection terminal, a device connection terminal, a computer connection terminal, a crystal oscillator Y1, a power control module, and an analog switching module;

[0026] The power control module is connected to the main power supply terminal, the secondary power supply terminal, the tertiary power supply terminal, the crystal oscillator Y1, and the analog switching module. The analog switching module is also connected to the tertiary power supply terminal, the equipment terminal, and the computer terminal.

[0027] The power control module includes: USB port power switch chip U1, LDO power chip U2, and USB-HUB chip U3;

[0028] The USB port power switch chip U1 is model CH217K, which has six pins: VIN, ISET, EN, VOUT, GND, and FLAG. The VIN pin of the USB port power switch chip U1 is connected to the main power supply terminal, the ISET pin is grounded through the second resistor R2, the EN pin is connected to the main power supply terminal through the first resistor R1, the FLAG pin is connected to the USB-HUB chip U3, the GND pin is grounded, the VOUT pin is connected to the LDO power chip U2, and the VOUT pin of the USB port power switch chip U1 is also connected to the secondary power supply terminal.

[0029] In this embodiment, the USB port power switch chip U1 can be used for power control of ports such as computers, USB hosts, USB hubs, and chargers. The current limiting threshold can be adjusted by an external resistor (i.e., the second resistor R2) to achieve circuit overcurrent protection, overtemperature protection, and undervoltage protection.

[0030] In this embodiment, the VIN pin of the USB port power switch chip U1 connects the main power supply to the circuit. The ISET pin determines the output current of the VOUT pin based on the resistance value of the second resistor R2, thereby reducing the main power supply voltage to the secondary power supply voltage. The secondary power supply then supplies power to the subsequent circuits, further achieving overcurrent and overvoltage protection.

[0031] Furthermore, the VIN pin of the USB port power switch chip U1 is also grounded through the first capacitor C1, and the VOUT pin is also grounded through the second capacitor C2.

[0032] The LDO power chip U2 is a low input voltage, low noise, low dropout linear regulator. The model number of the LDO power chip U2 is SGM2036S-3.3XN5G. It has five pins: IN, GND, EN, OUT, and BP. The IN pin of the LDO power chip U2 is connected to the secondary power supply, the GND pin is grounded, the EN pin is connected to the secondary power supply through the third resistor R3, the BP pin is grounded through the third capacitor C3, and the OUT pin is connected to the tertiary power supply. The OUT pin of the LDO power chip U2 is also connected to the USB-HUB chip U3.

[0033] Furthermore, the OUT pin of the LDO power chip U2 is also grounded through the fourth capacitor C4.

[0034] In this embodiment, the LDO power chip U2 reduces the voltage of the secondary power supply to the voltage of the tertiary power supply, and enables the tertiary power supply to stably power the subsequent circuits (i.e., the USB-HUB chip U3 and the analog switching module).

[0035] The USB-HUB chip U3 is model CH334F, mainly used for USB host port expansion, and widely used in computers, laptops and peripheral applications. Its VDD33 pin and 5V pin are connected to the three-level power supply connection terminal, the GND pin is grounded, the OVCUR pin is connected to the FLAG pin of the USB port power switch chip U1, the XO pin and XI pin are connected to the crystal oscillator Y1 respectively, and the DPU pin, DMU pin, DM1 pin and DP1 pin are connected to the analog switching module respectively.

[0036] Furthermore, the VDD33 pin of the USB-HUB chip U3 is also grounded through the fifth capacitor C5, the 5V pin is also grounded through the sixth capacitor C6, and the OVCUR pin is also connected to the third-level power supply terminal through the fourth resistor R4.

[0037] The crystal oscillator Y1 has four pins: X1, X2, and two GND pins. The GND pins are grounded. The X1 pin is connected to the XI pin of the USB-HUB chip U3, and the X2 pin is connected to the XO pin of the USB-HUB chip U3.

[0038] In this embodiment, crystal oscillator Y1 is used to provide a clock signal to USB-HUB chip U3.

[0039] Furthermore, the X1 pin of the crystal oscillator Y1 is also grounded through the eighth capacitor C8, and the X2 pin is also grounded through the seventh capacitor C7.

[0040] In this embodiment, as Figure 2 As shown, the voltage of the main power input is reduced to the secondary power supply through the USB port power switch chip U1. The voltage of the secondary power supply is then reduced to the tertiary power supply through the LDO power chip U2, and the voltage stability is continuously improved. Finally, the voltage of the tertiary power supply provides a stable operating voltage for the logic control of the USB-HUB chip U3 and the switching module.

[0041] The analog switching module includes: a first analog switching switch U4 and a second analog switching switch U5;

[0042] The first analog switch U4 is an SGM7222 with ten pins: S, HSD1+, HSD2+, D+, GND, D-, HSD2-, HSD1-, OE, and V+. The S pin of the first analog switch U4 is connected to the device connection terminal, the HSD2+ pin is connected to the DM1 pin of the USB-HUB chip U3, the GND pin is grounded, the V+ pin is connected to the three-level power supply connection terminal, the OE pin is grounded through the sixth resistor R6, the HSD2- pin is connected to the DP1 pin of the USB-HUB chip U3, the HSD1+ and HSD1- pins are both floating, and the D+ and D- pins are connected to the second analog switch U5.

[0043] Furthermore, the S pin of the first analog switching switch U4 is also grounded through the fifth resistor R5, and the V+ pin is also grounded through the ninth capacitor C9.

[0044] The second analog switch U5 is model SGM7222, which has ten pins: S pin, HSD1+ pin, HSD2+ pin, D+ pin, GND pin, D- pin, HSD2- pin, HSD1- pin, OE pin, and V+ pin. The S pin of the second analog switch U5 is connected to the S pin of the first analog switch U1. The HSD1+ pin is connected to the D+ pin of the first analog switch U1. The HSD2+ pin is connected to the DPU pin of the USB-HUB chip U3. The D+ and D- pins are both connected to the computer connection terminal. The GND pin is grounded. The V+ pin is connected to the three-level power supply connection terminal. The OE pin is grounded through the seventh resistor R7. The HSD1- pin is connected to the D- pin of the first analog switch U4. The HSD2- pin is connected to the DMU pin of the USB-HUB chip U3.

[0045] Furthermore, the V+ pin of the second analog switching switch U5 is also grounded through the tenth capacitor C10.

[0046] In this embodiment, as Figures 3-5 As shown, the device connection terminal is used to connect to the device CPU, and the computer connection terminal is used to connect to the computer CPU. When the device CPU outputs a low-level signal (i.e., IO1 is in a low-level state), on the one hand, the HSD1+ pin and D+ pin of the first analog switch U4 are internally connected, and the HSD1- pin and D- pin are internally connected; on the other hand, the HSD1+ pin and D+ pin of the second analog switch U5 are internally connected, and the HSD1- pin and D- pin are internally connected. The HSD1+ pin (USB-DP) and HSD1- pin (USB-DM) of the second analog switch U5 are connected to the device CPU, and the D+ pin (COM-DP) and D- pin (COM-DM) of the second analog switch U5 are connected to the computer CPU. Therefore, at this time, the device and computer are in a direct connection state (the device CPU and computer CPU are directly connected).

[0047] When the device CPU outputs a high-level signal (i.e., IO1 is in a high-level state), on the one hand, the HSD2+ pin and D+ pin of the first analog switch U4 are internally connected, and the HSD2- pin and D- pin are internally connected; on the other hand, the HSD2+ pin and D+ pin of the second analog switch U5 are internally connected, and the HSD2- pin and D- pin are internally connected. The HSD2+ pin (USB1+) and HSD2- pin (USB1-) of the first analog switch U4 are connected to the USB-HUB chip U3; the HSD2+ pin (USB-H-DPU) and HSD2- pin (USB-H-DMU) of the second analog switch U5 are connected to the USB-HUB chip U3. Therefore, the connection path between the device and the computer is broken at this time. Instead, the device first connects to the USB-HUB chip U3, and then the USB-HUB chip U3 connects to the computer (equivalent to the device, USB-HUB chip U3, and computer being connected in series).

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A signal transmission circuit based on a USB interface, characterized by, include: Main power connection terminal, secondary power connection terminal, tertiary power connection terminal, equipment connection terminal, computer connection terminal, crystal oscillator, power control module, analog switching module; The power control module is connected to the main power supply terminal, the secondary power supply terminal, the tertiary power supply terminal, the crystal oscillator, and the analog switching module. The analog switching module is also connected to the tertiary power supply terminal, the device terminal, and the computer terminal.

2. The signal transmission circuit based on USB interface according to claim 1, wherein, The power control module includes: a USB port power switch chip, an LDO power chip, and a USB-HUB chip. The USB port power switch chip has six pins: the VIN pin is connected to the main power supply terminal, the ISET pin is grounded through a second resistor, the EN pin is connected to the main power supply terminal through a first resistor, the FLAG pin is connected to the USB-HUB chip, the GND pin is grounded, the VOUT pin is connected to the LDO power chip, and the VOUT pin of the USB port power switch chip is also connected to the secondary power supply terminal.

3. The signal transmission circuit based on USB interface according to claim 2, characterized in that, The LDO power chip has five pins: the IN pin is connected to the secondary power supply, the GND pin is grounded, the EN pin is connected to the secondary power supply through a third resistor, the BP pin is grounded through a third capacitor, and the OUT pin is connected to the tertiary power supply. The OUT pin of the LDO power chip is also connected to the USB-HUB chip.

4. The signal transmission circuit based on USB interface according to claim 3, characterized in that, The VDD33 and 5V pins of the USB-HUB chip are connected to the three-level power supply connection terminal, the GND pin is grounded, the OVCUR pin is connected to the FLAG pin of the USB port power switch chip, the XO pin and XI pin are connected to the crystal oscillator respectively, and the DPU pin, DMU pin, DM1 pin and DP1 pin are connected to the analog switching module respectively.

5. The signal transmission circuit based on USB interface according to claim 4, characterized in that, The VDD33 pin of the USB-HUB chip is also grounded through the fifth capacitor, the 5V pin is also grounded through the sixth capacitor, and the OVCUR pin is also connected to the third-level power supply terminal through the fourth resistor.

6. The signal transmission circuit based on USB interface according to claim 5, characterized in that, The crystal oscillator has four pins: its GND pin is grounded, its X1 pin is connected to the XI pin of the USB-HUB chip, and its X2 pin is connected to the XO pin of the USB-HUB chip.

7. The signal transmission circuit based on USB interface according to claim 6, characterized in that, The analog switching module includes: a first analog switching switch and a second analog switching switch; The first analog switch has ten pins: its S pin is connected to the device connection terminal, its HSD2+ pin is connected to the DM1 pin of the USB-HUB chip, its GND pin is grounded, its V+ pin is connected to the three-level power supply connection terminal, its OE pin is grounded through the sixth resistor, its HSD2- pin is connected to the DP1 pin of the USB-HUB chip, its HSD1+ and HSD1- pins are both floating, and its D+ and D- pins are respectively connected to the second analog switch.

8. The signal transmission circuit based on USB interface according to claim 7, characterized in that, The S pin of the first analog switching switch is also grounded through the fifth resistor, and the V+ pin is also grounded through the ninth capacitor.

9. The signal transmission circuit based on USB interface according to claim 8, characterized in that, The second analog switch has ten pins. Its S pin is connected to the S pin of the first analog switch, the HSD1+ pin is connected to the D+ pin of the first analog switch, the HSD2+ pin is connected to the DPU pin of the USB-HUB chip, the D+ pin and the D- pin are both connected to the computer connection terminal, the GND pin is grounded, the V+ pin is connected to the three-level power supply connection terminal, the OE pin is grounded through the seventh resistor, the HSD1- pin is connected to the D- pin of the first analog switch, and the HSD2- pin is connected to the DMU pin of the USB-HUB chip.

10. The signal transmission circuit based on USB interface according to claim 9, characterized in that, The V+ pin of the second analog switching switch is also grounded through the tenth capacitor.

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