USB to serial port isolation circuit

Abstract

The utility model relates to a USB (Universal Serial Bus) to serial port isolation circuit, which comprises a PC (Personal Computer) USB interface circuit, a USB to serial port interface circuit, an isolation chip circuit and a target board UART (Universal Asynchronous Receiver / Transmitter) interface circuit, the isolation chip circuit at least comprises an isolation chip and is used for realizing electrical isolation between the computer and the target board; the input end of the PC USB interface circuit is connected with a computer, and the output end of the PC USB interface circuit is connected with the USB to serial port interface circuit; the output end of the USB to serial port interface circuit is connected with the isolation chip circuit; the output end of the isolation chip circuit is connected with the input end of the target board UART interface circuit; and the output end of the target board URAT interface circuit is connected with the target board. Through the UART interface used for assisting simulation debugging, data input and output channels are increased, the computer and the target board are electrically isolated through the isolation chip, damage of target equipment is effectively prevented from being transmitted to the computer, and the target equipment and the computer are protected.

Description

Technical Field

[0001] This application relates to the field of USB to serial port technology, and in particular to a USB to serial port isolation circuit. Background Technology

[0002] In the development of power electronic products such as charging devices and motor drives, researchers typically need to use a test system consisting of a computer USB port, digital power supply, oscilloscope, and matching debugging tools. This type of equipment requires a common ground connection to achieve simulation debugging, waveform monitoring, and data communication functions. However, actual debugging environments often present problems such as inconsistent ground levels, electromagnetic interference (EMI) causing overvoltage and overcurrent, etc. Direct circuit connections can transmit damage to the target board directly to the computer, resulting in damage to both the computer and the target device. Summary of the Invention

[0003] This application provides a USB-to-serial isolation circuit to solve the problem that overvoltage or overcurrent surges during simulation debugging in existing technologies may damage the UART interface and burn out the computer and target device. This application increases the data input and output channels through the UART interface used to assist in simulation debugging, and uses an isolation chip to electrically isolate the input from the computer's USB port from the output of the target board, effectively preventing damage to the target device from being transmitted to the computer, thus protecting both the target device and the computer.

[0004] In a first aspect, this application provides a USB to serial port isolation circuit, which includes a PC USB interface circuit, a USB to serial port interface circuit, an isolation chip circuit, and a target board UART interface circuit.

[0005] The isolation chip circuit includes at least one isolation chip for achieving electrical isolation between the computer and the target board.

[0006] The input end of the PC USB interface circuit is connected to the computer, and the output end is connected to the USB to serial port interface circuit.

[0007] The output terminal of the USB to serial port interface circuit is connected to the isolation chip circuit.

[0008] The output terminal of the isolation chip circuit is connected to the input terminal of the target board UART interface circuit;

[0009] The output terminal of the target board's URAT interface circuit is connected to the target board.

[0010] Optionally, the PC USB interface circuit includes multiple USB terminals, and the PC USB interface circuit transmits USB signals through the USB terminals;

[0011] The USB-to-serial interface circuit includes multiple USB-to-serial terminals. The USB-to-serial terminals on the input side of the USB-to-serial interface circuit are respectively connected to the output terminals of the PC USB interface circuit to realize the conversion of USB protocol to UART protocol.

[0012] Optionally, the USB to serial port terminals on the output side of the USB to serial port interface circuit are respectively connected to the input terminals of the isolation chip circuit, and each USB to serial port terminal transmits the UART signal to the isolation chip.

[0013] The isolation chip responds to the UART signal and transmits the UART signal to the UART interface circuit of the target board.

[0014] The target board UART interface circuit includes multiple target board UART terminals, each of which is connected to the output terminal of the isolation chip. Each target board UART terminal responds to the UART signal to assist in the simulation and debugging of the target board.

[0015] Optionally, the USB terminal includes a USB data positive terminal, a USB data negative terminal, a USB power positive terminal, and a USB power negative terminal.

[0016] Optionally, the USB to serial port terminal includes a first UART data transmitting end and a first UART data receiving end.

[0017] Optionally, the target board UART terminal includes a second UART data transmitter and a second UART data receiver, wherein the second UART data transmitter is connected to the receiver of the target board, and the second UART data receiver is connected to the transmitter of the target board.

[0018] Optionally, the USB to serial port interface circuit uses two unidirectional isolated channels, one of which is a reverse channel and the other is a forward channel.

[0019] Optionally, the input and output terminals of the isolation chip circuit are further provided with overvoltage protection circuits. The overvoltage protection circuits are used to prevent abnormal power supply of the target board from impacting the computer. Abnormal power supply includes interference signals and strong voltage and current.

[0020] Optionally, a buffer drive circuit is further provided between the PC USB interface circuit and the USB to serial port interface circuit. The buffer drive circuit is used to enhance the signal driving capability and reduce signal delay.

[0021] Optionally, the USB to serial interface circuit supports UART protocol switching, and protocol compatibility is achieved through the configuration of the UART signal lines.

[0022] Compared with the prior art, the technical solution provided in this application has the following advantages: This application increases the data input and output channels through the USB to serial port interface circuit, and realizes electrical isolation between the computer and the target board through the isolation chip, effectively preventing damage to the target device from being transmitted to the computer, thus protecting the target device and the computer. Furthermore, the isolation chip makes the power supply of the computer's USB end different from that of the target board, thereby automatically adapting to the power supply voltage of the target board to match target boards with different operating voltages. At the same time, it realizes the isolation of each data signal of the USB to serial port from the power ground, which helps to avoid signal interference. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0026] Figure 1 A schematic diagram of a USB-to-serial port isolation circuit provided in an embodiment of this application;

[0027] Figure 2 This is a circuit diagram of a USB to serial port isolation circuit provided in an embodiment of this application. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0030] To address the problems in the prior art, this application adds data input and output channels through a USB-to-serial interface circuit and achieves electrical isolation between the computer and the target board through an isolation chip, effectively preventing damage to the target device from being transmitted to the computer, thus protecting both the target device and the computer. Furthermore, the isolation chip ensures that the power supply at the computer's USB end is different from the power supply at the target board, enabling automatic adaptation to the target board's power supply voltage to match target boards with different operating voltages. At the same time, it isolates the data signals of the USB-to-serial port from the power ground, which helps to avoid signal interference.

[0031] Figure 1 This is a schematic diagram of a USB-to-serial port isolation circuit provided in an embodiment of this application. The USB-to-serial port isolation circuit includes a PC USB interface circuit, a USB-to-serial port interface circuit, an isolation chip circuit, and a target board UART interface circuit.

[0032] The isolation chip circuit includes at least one isolation chip for achieving electrical isolation between the computer and the target board.

[0033] The input end of the PC USB interface circuit is connected to the computer, and the output end is connected to the USB to serial port interface circuit.

[0034] The output terminal of the USB to serial port interface circuit is connected to the isolation chip circuit.

[0035] The output terminal of the isolation chip circuit is connected to the input terminal of the target board UART interface circuit;

[0036] The output terminal of the target board's URAT interface circuit is connected to the target board.

[0037] Currently, the development of charging devices and motor drivers requires the use of computers, digital power supplies, oscilloscopes, USB-to-UART / RS485 communication adapters, and other tools, all connected via a common ground for simulation, waveform monitoring, and communication. Since charging devices and motor drivers are inductive loads, overvoltage or overcurrent surges may occur in the target device during simulation and debugging, impacting the USB interface and conducting to the computer's motherboard, potentially burning it out. Furthermore, reversed power supply connections and large ESD voltage differences between the target device and the computer's ground level can also cause damage to be conducted from the target device to the computer due to direct circuit connections, leading to the burnout of both the computer and the target device. This application addresses this issue by using an intermediate isolation circuit, including at least one isolation chip, to electrically isolate the computer from the target device, preventing damage from the target device from being transmitted to the computer.

[0038] In this embodiment, electrical isolation is achieved between the target circuit and the computer, while overvoltage and overcurrent signals are implemented to avoid the influence of ground potential difference and ESD of the target device, thus protecting the safety of both the computer and the target device. For debugging environments with inconsistent ground levels and severe EMI, and for objective requirements such as input / output data, this approach effectively protects device safety while matching target boards with different power supply voltages to complete the debugging task.

[0039] Optionally, the PC USB interface circuit includes multiple USB terminals, and the PC USB interface circuit transmits USB signals through the USB terminals;

[0040] The USB-to-serial interface circuit includes multiple USB-to-serial terminals. The USB-to-serial terminals on the input side of the USB-to-serial interface circuit are respectively connected to the output terminals of the PC USB interface circuit to realize the conversion of USB protocol to UART protocol.

[0041] USB to Serial is a conversion solution that converts a USB interface into traditional serial port (serial communication interface, such as RS-232, TTL UART, RS-485, etc.) signals. It is commonly used as a communication bridge between modern computers and older devices or embedded systems. One application of UART is communication between a microcontroller and a PC using a USB to TTL module (such as CH340, CP2102) connected to the PC's USB interface for development debugging, data acquisition, and log output. Essentially, USB to UART conversion converts the USB data from the host (such as a computer) into UART serial signals (TX, RX) that the MCU can recognize, enabling bidirectional communication. UART (Universal Asynchronous Receiver / Transmitter) is a common serial communication protocol used for point-to-point communication between devices.

[0042] Optionally, the USB to serial port terminals on the output side of the USB to serial port interface circuit are respectively connected to the input terminals of the isolation chip circuit, and each USB to serial port terminal transmits the UART signal to the isolation chip.

[0043] The isolation chip responds to the UART signal and transmits the UART signal to the UART interface circuit of the target board.

[0044] The target board UART interface circuit includes multiple target board UART terminals, each of which is connected to the output terminal of the isolation chip. Each target board UART terminal responds to the UART signal to assist in the simulation and debugging of the target board.

[0045] Because EMI from the target device causes electronic signal distortion, and the ground level inconsistency between the target device and the computer can cause common-mode interference, this affects simulation debugging and, in severe cases, even makes debugging impossible. This application adds a UART interface to assist debugging, increasing data input and output channels and aiding simulation debugging. Simultaneously, through an intermediate isolation circuit, the impact of EMI from the target device on the simulator and computer is significantly reduced, and common-mode interference between the target device and the computer is eliminated. Electrical isolation between the target device and the computer isolates data input and data output.

[0046] Figure 2 This is a circuit diagram of a USB to serial port isolation circuit provided in an embodiment of this application.

[0047] Optionally, the USB terminal includes a USB data positive terminal, a USB data negative terminal, a USB power positive terminal, and a USB power negative terminal.

[0048] In this embodiment, the PC USB interface includes the following terminals: VBUS: USB interface power positive terminal, DM: USB data negative terminal, DP: USB data positive terminal, and GND: USB interface power negative terminal.

[0049] Optionally, the USB to serial port terminal includes a first UART data transmitting end and a first UART data receiving end.

[0050] In this embodiment, the signal terminals of the USB-to-serial interface are as follows: UART_TX: serial data transmitter, UART_RX: serial data receiver. The USB-to-serial interface typically only requires three terminals to connect to the UART interface of the target device, including: two digital signals (UART_TX, UART_RX) and one power supply (GND). Relative to the target device, UART_RX is an input signal, and UART_TX is an output signal.

[0051] Optionally, the target board UART terminal includes a second UART data transmitter and a second UART data receiver, wherein the second UART data transmitter is connected to the receiver of the target board, and the second UART data receiver is connected to the transmitter of the target board.

[0052] In this embodiment of the application, the UART terminal of the target board includes: UART_TX': serial data transmitting end, UART_RX': serial data receiving end, wherein UART_TX' is connected to the RX of the target board, and UART_RX' is connected to the TX of the target board.

[0053] Optionally, the USB to serial port interface circuit uses two unidirectional isolated channels, one of which is a reverse channel and the other is a forward channel.

[0054] In this embodiment, the USB to serial port uses an isolation chip CA-IS3722HS with two unidirectional isolation channels, one of which is a reverse channel and the other is a forward channel, to achieve isolation.

[0055] In this embodiment, an isolation chip is used to make the power supply of the computer's USB port different from that of the target board, so as to automatically adapt to the power supply voltage of the target board to match the target board with different operating voltages. At the same time, it isolates the data signals of the USB to serial port from the power ground, which helps to avoid signal interference.

[0056] Optionally, the input and output terminals of the isolation chip circuit are further provided with overvoltage protection circuits. The overvoltage protection circuits are used to prevent abnormal power supply of the target board from impacting the computer. Abnormal power supply includes interference signals and strong voltage and current.

[0057] In this embodiment, an overvoltage protection function is also provided. The overvoltage protection circuit prevents line burnout or signal noise problems caused by excessive voltage or abnormal power supply surges at either the simulator end or the target device end. This is beneficial to the safety of the computer and the target board and to the accuracy of debugging.

[0058] Optionally, a buffer drive circuit is further provided between the PC USB interface circuit and the USB to serial port interface circuit. The buffer drive circuit is used to enhance the signal driving capability and reduce signal delay.

[0059] In the embodiments of this application, the buffer drive circuit is a circuit structure used in digital or analog circuits for signal amplification, isolation, or driving load. It mainly plays the role of improving signal driving capability, preventing signal distortion or loading interference to isolate circuits before and after the signal, and improving system stability. It is beneficial to enhance signal driving capability and reduce signal delay.

[0060] Optionally, the USB to serial interface circuit supports UART protocol switching, and protocol compatibility is achieved through the configuration of the UART signal lines.

[0061] Common UART protocol switching methods are as follows:

[0062] (1) Multiple UART port switching (software selection), applicable scenarios: MCU has multiple UART interfaces, such as USART1 and USART2, which are dynamically selected according to the function.

[0063] (2) Physical protocol layer switching (RS232 / RS485 / TTL), applicable scenario: a UART communication circuit supports RS232, RS485 and TTL at the same time (usually using jumpers, relays, electronic switches, etc. for switching).

[0064] (3) UART communication parameter switching (dynamic baud rate, etc.), applicable scenarios: the system supports multiple peripherals with different communication rates and formats, and requires dynamic configuration of UART parameters.

[0065] (4) Simulate UART (Software UART) multi-channel switching, applicable scenario: MCU has only one hardware UART, but needs to support multiple serial port devices (low speed).

[0066] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0067] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0068] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0069] In the embodiments provided in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0070] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0071] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0072] The implementation of all or part of the processes in the methods of the above embodiments can also be accomplished by a computer program product. When the computer program product is run on a terminal device, the terminal device can implement the steps in the various method embodiments described above.

[0073] The embodiments described above are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application 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; and these 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 application, and should all be included within the protection scope of this application.

Claims

1. A USB-to-serial port isolation circuit, characterized in that, The USB-to-serial isolation circuit comprises a PC USB interface circuit, a USB-to-serial interface circuit, an isolation chip circuit and a target board UART interface circuit. The isolation chip circuit comprises at least one isolation chip, and is configured to realize electrical isolation between the computer and the target board. An input end of the PC USB interface circuit is connected with the computer, and an output end of the PC USB interface circuit is connected with the USB-to-serial interface circuit. An output end of the USB-to-serial interface circuit is connected with the isolation chip circuit. An output end of the isolation chip circuit is connected with an input end of the target board UART interface circuit. An output end of the target board UART interface circuit is connected with the target board.

2. The USB-to-serial isolation circuit according to claim 1, wherein the PC USB interface circuit comprises a plurality of USB terminals, and the PC USB interface circuit transmits USB signals through the USB terminals. The USB-to-serial interface circuit comprises a plurality of USB-to-serial terminals, and the USB-to-serial terminals on the input end side of the USB-to-serial interface circuit are respectively connected with the output ends of the PC USB interface circuit, so as to realize conversion of USB protocol into UART protocol.

3. The USB-to-serial isolation circuit according to claim 2, wherein the USB-to-serial terminals on the output end side of the USB-to-serial interface circuit are respectively connected with the input ends of the isolation chip circuit, and each of the USB-to-serial terminals transmits the UART signals to the isolation chip. The isolation chip responds to the UART signals and transmits the UART signals to the target board UART interface circuit. The target board UART interface circuit comprises a plurality of target board UART terminals, and each of the target board UART terminals is respectively connected with the output end of the isolation chip, and each of the target board UART terminals responds to the UART signals, so as to assist in simulation debugging of the target board. The USB terminals comprise USB data positive terminals, USB data negative terminals, USB power positive terminals and USB power negative terminals. The USB-to-serial terminals comprise first UART data transmission terminals and first UART data receiving terminals.

4. The USB-to-serial isolation circuit of claim 2, wherein, The target board UART terminals comprise second UART data transmission terminals and second UART data receiving terminals, the second UART data transmission terminals are connected with receiving terminals of the target board, and the second UART data receiving terminals are connected with transmission terminals of the target board.

5. The USB-to-serial isolation circuit of claim 2, wherein, The USB-to-serial interface circuit adopts two one-way isolation channels, one of which is a reverse channel and the other of which is a forward channel.

6. The USB-to-serial isolation circuit of claim 3, wherein, The input end and the output end of the isolation chip circuit are further provided with an overvoltage protection circuit, the overvoltage protection circuit is configured to prevent abnormal power supply of the target board from impacting the computer, and the abnormal power supply comprises interference signals and strong voltage and current.

7. The USB-to-serial isolation circuit of claim 1, wherein, A buffer driving circuit is further arranged between the PC USB interface circuit and the USB-to-serial interface circuit, and the buffer driving circuit is configured to enhance signal driving capability and reduce signal delay.

8. The USB-to-serial isolation circuit of claim 1, wherein, ​ 9. The USB-to-serial isolation circuit of claim 1, wherein, ​ 10. The USB-to-serial isolation circuit of claim 1, wherein, The USB-to-serial interface circuit supports UART protocol switching function, and realizes protocol compatibility through configuration of UART signal lines. The USB-to-serial interface circuit supports UART protocol switching function, and realizes protocol compatibility through configuration of UART signal lines.

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