Isolated USB-to-multi-serial port circuit with adjustable voltage

Abstract

The invention discloses a USB-to-multi-serial-port voltage-adjustable circuit with isolation. The circuit comprises a PC, an electrical isolation module, a USB concentrator, a USB female seat, a USB conversion chip, serial ports, a four-wire-to-three-wire circuit, a 5V / 12V level conversion circuit and an RS485 circuit. Data or signals sent by the PC are isolated by the electrical isolation module and then enter the USB concentrator, the USB concentrator connects the signals to the USB female seat and the USB conversion chip, and the USB conversion chip transmits the signals to the serial port, the four-wire to three-wire circuit, the 5V / 12V level conversion circuit and the RS485 circuit. According to the invention, the Type-C interface is connected with the computer; electrical isolation is carried out through a digital isolation module; a plurality of serial ports can be used at the same time; two USB isolation expansion ports; the voltage of 3.3 V, 5V and 12V can be adjusted.

Description

Technical Field

[0001] The present invention relates to the technical field of USB to multi-serial port circuits, and specifically to a circuit with isolation for USB to multi-serial port and adjustable voltage. Background Art

[0002] During the testing process of products, USB to serial port tools are essential. Currently, the ones in use are all single. If multiple are needed simultaneously, multiple serial port tools have to be connected. Due to the influence of the number of computer USB ports, it may be necessary to connect a USB HUB. Moreover, these serial port tools are non-isolated, and it is very easy to damage the computer when debugging high-power products. To solve this problem, this circuit with isolation for USB to multi-serial port and adjustable voltage is designed. Summary of the Invention

[0003] The purpose of the present invention is to provide a circuit with isolation for USB to multi-serial port and adjustable voltage to solve the problems in the prior art.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A circuit with isolation for USB to multi-serial port and adjustable voltage, including a PC, an electrical isolation module, a USB hub, a USB female socket, a USB conversion chip, serial ports, a four-wire to three-wire circuit, a 5V / 12V level conversion circuit, and an RS485 circuit;

[0005] The data or signals sent by the PC enter the USB hub after being isolated by the electrical isolation module. The USB hub connects the signals to the USB female socket and the USB conversion chip respectively. The USB conversion chip transports the signals to the serial ports, the four-wire to three-wire circuit, the 5V / 12V level conversion circuit, and the RS485 circuit.

[0006] Preferably, the electrical isolation module includes a boost circuit. The boost circuit includes an input voltage, a filter capacitor C2, a boost chip U2, a filter capacitor C3, a switch K1, and an output voltage. The input voltage is filtered by the filter capacitor C2. The filter capacitor C2 is connected to the input terminal of the boost chip U2. The output terminal of the boost chip U2 is connected to the filter capacitor C3. The filter capacitor C3 is connected to the switch K1.

[0007] Preferably, the electrical isolation module includes resistor R3, resistor R4, chip U3, resistor R5, resistor R6, capacitor C4, capacitor C5, capacitor C6, and capacitor C7; the UD- signal is connected to pin 5 of chip U3 through resistor R3, and the UD+ signal is connected to pin 6 of chip U3 through resistor R4; the D- signal is connected to pin 10 of chip U3 through resistor R5, and the D+ signal is connected to pin 11 of chip U3 through resistor R6; capacitor C4 and capacitor C5 are respectively connected between the 5V power supply and ground, and capacitor C6 and capacitor C7 are respectively connected between the 3.3V power supply and ground.

[0008] Preferably, two USB hubs are provided.

[0009] One of the USB hubs includes chip U7, crystal oscillator X2, capacitor C16, capacitor C17, capacitor C18, and capacitor C19. The crystal oscillator X2 is connected to chip U7, and capacitor C18 and capacitor C19 are respectively connected to both ends of the crystal oscillator X2.

[0010] The other USB hub includes chip U6, crystal oscillator X1, capacitor C12, capacitor C13, capacitor C14, and capacitor C15. The crystal oscillator X1 is connected to chip U6, and capacitor C14 and capacitor C15 are respectively connected to both ends of the crystal oscillator X1.

[0011] Preferably, a total of 5 USB conversion chips are provided, and a total of two serial ports are provided.

[0012] One of the USB conversion chips includes chip U8, capacitor C21, and capacitor C22. Capacitor C21 and capacitor C22 are respectively connected between VCC and GND, and between RXD and TXD and ground.

[0013] One of the USB conversion chips includes chip U9, capacitor C22, and capacitor C23. Capacitor C22 and capacitor C23 are respectively connected between VCC and GND, and between RXD and TXD and ground.

[0014] One of the USB conversion chips includes chip U10, capacitor C24, and capacitor C25. Capacitor C24 and capacitor C25 are respectively connected between VCC and GND, and between RXD and TXD and ground.

[0015] One of the USB conversion chips includes chip U11, capacitor C26, and capacitor C27. Capacitor C26 and capacitor C27 are respectively connected between VCC and GND, and between RXD and TXD and ground.

[0016] One of the USB conversion chips includes chip U12, capacitor C28, and capacitor C29. Capacitor C28 and capacitor C29 are respectively connected between VCC and GND, and between RXD and TXD and ground.

[0017] Preferably, the four-wire to three-wire circuit includes diode bridge D1, transistor Q1, transistor Q2, resistor R8, resistor R9, resistor R10, resistor R11, resistor R12, resistor R13, resistor R14. The base of transistor Q1 is connected to VCC3 through resistor R9 and resistor R10, and the emitter of transistor Q1 is grounded through resistor R11. The collector of transistor Q1 is connected to RXD3 through resistor R8 and grounded through capacitor C26. The base of transistor Q2 is connected to VCC3 through resistor R13, the emitter of transistor Q2 is grounded through resistor R14, and the collector of transistor Q2 is connected to TXD3 through resistor R12 and grounded through capacitor C26.

[0018] Preferably, the 5V / 12V level conversion circuit includes a 5V to 12V level conversion circuit and a 12V to 5V level conversion circuit.

[0019] The 5V to 12V level conversion circuit includes transistor Q6, resistor R15, resistor R16, resistor R17, resistor R18, capacitor C29, and diode bridge D2.

[0020] The 12V to 5V level conversion circuit includes transistor Q3, transistor Q4, transistor Q5, resistor R19, resistor R20, resistor R21, resistor R22, capacitor C30, and diode bridge D3.

[0021] Preferably, the RS485 circuit includes chip U13, capacitor C33, resistor R25, resistor R26, diode D4, diode D5, diode D6. Resistor R25 is connected between pin 7 of chip U13 and ground, resistor R26 is connected between pin 6 of chip U13 and ground, diode D4 is connected between pin 7 of chip U13 and ground, diode D5 is connected between pin 6 of chip U13 and ground, and diode D6 is connected between pin 6 of chip U13 and ground.

[0022] Preferably, it further includes a voltage conversion circuit. The voltage conversion circuit includes a 12V to 5V voltage circuit and a 5V to 3.3V voltage circuit. The 12V to 5V voltage circuit includes 5V voltage regulator U4, capacitor C8, and capacitor C9. The 5V to 3.3V voltage circuit includes 3.3V voltage regulator U5, capacitor C10, and capacitor C11.

[0023] Preferably, it further includes a USB Type-C interface circuit, and the USB Type-C interface circuit includes a power indicator light, a filter circuit, and a signal protection circuit.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: connecting to a computer using a Type-C interface; performing electrical isolation through a digital isolation module; having multi-serial port functions and being able to use them simultaneously; two USB isolation expansion ports; adjustable voltages of 3.3V, 5V, and 12V; achieving electrical isolation between the computer and the product; multi-serial port functions; USB expansion functions; adjustable multi-voltages. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings are used to provide further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0026] Figure 1 is the schematic diagram of the present invention;

[0027] Figure 2 is the structural schematic diagram of the boost circuit of the present invention;

[0028] Figure 3 is the structural schematic diagram of the electrical isolation module of the present invention;

[0029] Figure 4 is the structural schematic diagram of the first USB hub of the present invention;

[0030] Figure 5 is the structural schematic diagram of the second USB hub of the present invention;

[0031] Figure 6 is the structural schematic diagram of the USB conversion chip of the serial port of the present invention;

[0032] Figure 7 is the structural schematic diagram of the USB conversion chip of the four-wire to three-wire circuit of the present invention;

[0033] Figure 8 is the structural schematic diagram of the USB conversion chip of the 5V / 12V level conversion circuit of the present invention;

[0034] Figure 9 is the structural schematic diagram of the USB conversion chip of the RS485 circuit of the present invention;

[0035] Figure 10 is the structural schematic diagram of the TTL four-wire to three-wire of the present invention;

[0036] Figure 11 is the structural schematic diagram of the 5V / 12V level conversion circuit of the present invention;

[0037] Figure 12 It is a schematic structural diagram of the RS485 circuit of the present invention;

[0038] Figure 13 It is a schematic structural diagram of the USB expansion port of the present invention;

[0039] Figure 14 It is a schematic structural diagram of the voltage conversion module of the present invention;

[0040] Figure 15 It is a schematic structural diagram of the USB Type-C interface circuit of the present invention. Specific embodiments

[0041] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0042] Please refer to Figures 1-15 , in an embodiment of the present invention, a circuit for converting USB to multiple serial ports with isolation and adjustable voltage includes a PC, an electrical isolation module, a USB hub, a USB female socket, a USB conversion chip, a serial port, a four-wire to three-wire circuit, a 5V / 12V level conversion circuit, and an RS485 circuit;

[0043] The data or signals sent by the PC enter the USB hub after being isolated by the electrical isolation module. The USB hub connects the signals to the USB female socket and the USB conversion chip respectively. The USB conversion chip sends the signals to the serial port, the four-wire to three-wire circuit, the 5V / 12V level conversion circuit, and the RS485 circuit.

[0044] Preferably, the electrical isolation module includes a boost circuit. The boost circuit includes an input voltage, a filter capacitor C2, a boost chip U2, a filter capacitor C3, a switch K1, and an output voltage. The input voltage is filtered by the filter capacitor C2. The filter capacitor C2 is connected to the input end of the boost chip U2. The output end of the boost chip U2 is connected to the filter capacitor C3. The filter capacitor C3 is connected to the switch K1.

[0045] Preferably, the electrical isolation module includes resistor R3, resistor R4, chip U3, resistor R5, resistor R6, capacitor C4, capacitor C5, capacitor C6, and capacitor C7; the UD- signal is connected to pin 5 of chip U3 through resistor R3, and the UD+ signal is connected to pin 6 of chip U3 through resistor R4; the D- signal is connected to pin 10 of chip U3 through resistor R5, and the D+ signal is connected to pin 11 of chip U3 through resistor R6; capacitor C4 and capacitor C5 are respectively connected between the 5V power supply and ground, and capacitor C6 and capacitor C7 are respectively connected between the 3.3V power supply and ground.

[0046] Preferably, two USB hubs are provided.

[0047] One of the USB hubs includes chip U7, crystal oscillator X2, capacitor C16, capacitor C17, capacitor C18, and capacitor C19. The crystal oscillator X2 is connected to chip U7, and capacitor C18 and capacitor C19 are respectively connected to both ends of the crystal oscillator X2.

[0048] The other USB hub includes chip U6, crystal oscillator X1, capacitor C12, capacitor C13, capacitor C14, and capacitor C15. The crystal oscillator X1 is connected to chip U6, and capacitor C14 and capacitor C15 are respectively connected to both ends of the crystal oscillator X1.

[0049] Preferably, 5 USB conversion chips are provided in total, and two serial ports are provided in total.

[0050] One of the USB conversion chips includes chip U8, capacitor C21, and capacitor C22. Capacitor C21 and capacitor C22 are respectively connected between VCC and GND, and between RXD and TXD and ground.

[0051] One of the USB conversion chips includes chip U9, capacitor C22, and capacitor C23. Capacitor C22 and capacitor C23 are respectively connected between VCC and GND, and between RXD and TXD and ground.

[0052] One of the USB conversion chips includes chip U10, capacitor C24, and capacitor C25. Capacitor C24 and capacitor C25 are respectively connected between VCC and GND, and between RXD and TXD and ground.

[0053] One of the USB conversion chips includes chip U11, capacitor C26, and capacitor C27. Capacitor C26 and capacitor C27 are respectively connected between VCC and GND, and between RXD and TXD and ground.

[0054] One of the USB conversion chips includes chip U12, capacitor C28, and capacitor C29. Capacitor C28 and capacitor C29 are respectively connected between VCC and GND, and between RXD and TXD and ground.

[0055] Preferably, the four-wire to three-wire circuit includes diode bridge D1, transistor Q1, transistor Q2, resistor R8, resistor R9, resistor R10, resistor R11, resistor R12, resistor R13, resistor R14. The base of transistor Q1 is connected to VCC3 through resistor R9 and resistor R10. The emitter of transistor Q1 is grounded through resistor R11. The collector of transistor Q1 is connected to RXD3 through resistor R8 and grounded through capacitor C26. The base of transistor Q2 is connected to VCC3 through resistor R13. The emitter of transistor Q2 is grounded through resistor R14. The collector of transistor Q2 is connected to TXD3 through resistor R12 and grounded through capacitor C26.

[0056] Preferably, the 5V / 12V level conversion circuit includes a 5V to 12V level conversion circuit and a 12V to 5V level conversion circuit.

[0057] The 5V to 12V level conversion circuit includes transistor Q6, resistor R15, resistor R16, resistor R17, resistor R18, capacitor C29, and diode bridge D2.

[0058] The 12V to 5V level conversion circuit includes transistor Q3, transistor Q4, transistor Q5, resistor R19, resistor R20, resistor R21, resistor R22, capacitor C30, and diode bridge D3.

[0059] Preferably, the RS485 circuit includes chip U13, capacitor C33, resistor R25, resistor R26, diode D4, diode D5, diode D6. Resistor R25 is connected between pin 7 of chip U13 and ground. Resistor R26 is connected between pin 6 of chip U13 and ground. Diode D4 is connected between pin 7 of chip U13 and ground. Diode D5 is connected between pin 6 of chip U13 and ground. Diode D6 is connected between pin 6 of chip U13 and ground.

[0060] Preferably, it further includes a voltage conversion circuit. The voltage conversion circuit includes a 12V to 5V voltage circuit and a 5V to 3.3V voltage circuit. The 12V to 5V voltage circuit includes 5V voltage regulator U4, capacitor C8, and capacitor C9. The 5V to 3.3V voltage circuit includes 3.3V voltage regulator U5, capacitor C10, and capacitor C11.

[0061] Preferably, it further includes a USB Type-C interface circuit, and the USB Type-C interface circuit includes a power indicator light, a filtering circuit, and a signal protection circuit.

[0062] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A circuit with isolation from USB to multiple serial ports and adjustable voltage, characterized in that: Including PC, electrical isolation module, USB hub, USB socket, USB conversion chip, serial port, four-wire to three-wire circuit, 5V / 12V level conversion circuit, RS485 circuit; The data or signal sent by the PC enters the USB hub after isolation processing by the electrical isolation module. The USB hub connects the signal to the USB socket and the USB conversion chip respectively. The USB conversion chip transmits the signal to the serial port, the four-wire to three-wire circuit, the 5V / 12V level conversion circuit, and the RS485 circuit.

2. The isolated USB to multiple serial ports circuit with adjustable voltage according to claim 1, characterized in that: The electrical isolation module includes a boost circuit, which includes an input voltage, a filter capacitor C2, a boost chip U2, a filter capacitor C3, a switch K1, and an output voltage. The input voltage is filtered by the filter capacitor C2, the filter capacitor C2 is connected to the input end of the boost chip U2, the output end of the boost chip U2 is connected to the filter capacitor C3, and the filter capacitor C3 is connected to the switch K1.

3. The isolated USB to multiple serial ports circuit with adjustable voltage according to claim 2, characterized in that: The electrical isolation module includes resistor R3, resistor R4, chip U3, resistor R5, resistor R6, capacitor C4, capacitor C5, capacitor C6 and capacitor C7; the UD- signal is connected to pin 5 of chip U3 through resistor R3, and the UD+ signal is connected to pin 6 of chip U3 through resistor R4; the D- signal is connected to pin 10 of chip U3 through resistor R5, and the D+ signal is connected to pin 11 of chip U3 through resistor R6; capacitor C4 and capacitor C5 are respectively connected between a 5V power supply and ground, and capacitor C6 and capacitor C7 are respectively connected between a 3.3V power supply and ground.

4. The isolated USB to multiple serial ports circuit with adjustable voltage according to claim 1, characterized in that: The USB hub is provided with two; One of the USB hubs includes a chip U7, a crystal oscillator X2, a capacitor C16, a capacitor C17, a capacitor C18 and a capacitor C19, the crystal oscillator X2 is connected to the chip U7, and the capacitor C18 and the capacitor C19 are respectively connected to both ends of the crystal oscillator X2; Another USB hub includes a chip U6, a crystal oscillator X1, a capacitor C12, a capacitor C13, a capacitor C14 and a capacitor C15. The crystal oscillator X1 is connected to the chip U6, and the capacitor C14 and the capacitor C15 are respectively connected to two ends of the crystal oscillator X1.

5. The isolated USB to multiple serial ports circuit with adjustable voltage according to claim 1, characterized in that: There are five USB conversion chips in total, and two serial ports in total; A USB conversion chip includes a chip U8, a capacitor C21 and a capacitor C22, wherein the capacitor C21 and the capacitor C22 are connected between VCC and GND and between RXD and TXD and ground respectively; A USB conversion chip includes a chip U9, a capacitor C22 and a capacitor C23, wherein the capacitor C22 and the capacitor C23 are respectively connected between VCC and GND and between RXD and TXD and ground; A USB conversion chip includes a chip U10, a capacitor C24 and a capacitor C25, wherein the capacitor C24 and the capacitor C25 are respectively connected between VCC and GND and between RXD and TXD and ground; A USB conversion chip includes a chip U11, a capacitor C26 and a capacitor C27, wherein the capacitor C26 and the capacitor C27 are connected between VCC and GND and between RXD and TXD and ground respectively; One of the USB conversion chips includes a chip U12, a capacitor C28 and a capacitor C29, wherein the capacitor C28 and the capacitor C29 are connected between VCC and GND and between RXD and TXD and ground respectively.

6. The isolated USB to multiple serial ports circuit with adjustable voltage according to claim 1, characterized in that: The four-wire to three-wire circuit includes a diode bridge D1, a transistor Q1, a transistor Q2, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, and a resistor R14; the base of the transistor Q1 is connected to VCC3 through resistors R9 and R10, and the emitter of the transistor Q1 is grounded through resistor R11; the collector of the transistor Q1 is connected to RXD3 through resistor R8 and is grounded through capacitor C26; the base of the transistor Q2 is connected to VCC3 through resistor R13, the emitter of the transistor Q2 is grounded through resistor R14, and the collector of the transistor Q2 is connected to TXD3 through resistor R12 and is grounded through capacitor C26.

7. The isolated USB to multiple serial ports circuit with adjustable voltage according to claim 1, characterized in that: The 5V / 12V level conversion circuit includes a 5V to 12V level conversion circuit and a 12V to 5V level conversion circuit; The 5V to 12V level conversion circuit includes a transistor Q6, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a capacitor C29, and a diode bridge D2; The 12V to 5V level conversion circuit includes a transistor Q3, a transistor Q4, a transistor Q5, a resistor R19, a resistor R20, a resistor R21, a resistor R22, a capacitor C30, and a diode bridge D3.

8. The isolated USB to multiple serial ports circuit with adjustable voltage according to claim 1, characterized in that: The RS485 circuit includes a chip U13, a capacitor C33, a resistor R25, a resistor R26, a diode D4, a diode D5, and a diode D6; the resistor R25 is connected between pin 7 of the chip U13 and the ground, the resistor R26 is connected between pin 6 of the chip U13 and the ground, the diode D4 is connected between pin 7 of the chip U13 and the ground, the diode D5 is connected between pin 6 of the chip U13 and the ground, and the diode D6 is connected between pin 6 of the chip U13 and the ground.

9. The isolated USB to multiple serial ports circuit with adjustable voltage according to claim 1, characterized in that: It also includes a voltage conversion circuit, which includes a 12V to 5V voltage circuit and a 5V to 3.3V voltage circuit. The 12V to 5V voltage circuit includes a 5V voltage regulator U4, a capacitor C8, and a capacitor C9; the 5V to 3.3V voltage circuit includes a 3.3V voltage regulator U5, a capacitor C10, and a capacitor C11.

10. The isolated USB to multiple serial ports circuit with adjustable voltage according to claim 1, characterized in that: It also includes a USB Type-C interface circuit, which includes a power indicator light, a filter circuit and a signal protection circuit.

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