Single-interface usb signal automatic switching circuit, data line and electronic device

Abstract

The utility model relates to electronic device, interface circuit technical field especially, a single interface USB signal automatic switching circuit, data line and electronic device are provided. The circuit includes type C female seat, main control chip, image processing chip and signal switching unit. Type C female seat has the passageway for USB data transmission and direction identification signal input end SBU1 end and SBU2 end, signal switching unit has public data passageway, first data channel, second data channel, selection control end SEL and enable control end OE, wherein SBU1 end is input to the selection end after voltage division or limiting amplitude, and the enable end is grounded through the pull-down resistance to maintain effective. When the plug is inserted positively and reversely, SBU1 end and SBU2 end form complementary level at the female seat side, drive signal switching unit to switch USB data passageway automatically, make positive insertion connect main control chip, and reverse insertion connect image processing chip. The circuit realizes the automatic switching of two chip USB signals under single type C interface, simplifies the debugging structure, reduces the flying wire operation, improves signal stability and assembly efficiency.

Description

Technical Field

[0001] This utility model relates to the field of electronic devices and interface circuit technology, and in particular to a single-interface USB signal automatic switching circuit, data cable and electronic device. Background Technology

[0002] In miniaturized products such as AI cameras, a main control chip and an image signal processing chip are often configured simultaneously to handle wireless transmission and image processing tasks respectively. During the debugging phase, both chips usually need to complete firmware burning, data transmission, or log capture via USB. However, due to structural space and appearance requirements, finished products often only have one Type-C female connector. The traditional approach is to switch the USB connection object on the motherboard by using jumpers, jumpers, or temporary wiring changes. This not only consumes a lot of engineering time but also easily introduces the risk of signal instability and accidental contact.

[0003] On the other hand, the inventors discovered that SBU1 and SBU2 of the Type-C interface are usually unconnected when not involving analog audio or auxiliary channels. Furthermore, the correct and reverse insertion of Type-C will cause SBU1 and SBU2 to be swapped as seen on the product side. This provides the conditions for automatic switching through SBU level identification.

[0004] Therefore, how to achieve stable switching of the USB channel between two chips by simply adjusting the plug orientation without adding extra physical switches and external buttons has become a technical problem that urgently needs to be solved in engineering.

[0005] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Utility Model Content

[0006] The purpose of this invention is to provide a single-interface USB signal automatic switching circuit, a Type-A to Type-C data cable with direction recognition level output, and a Type-C single-interface electronic device to address the shortcomings of existing technologies. The aim is to achieve stable switching of the USB channel between two chips by simply adjusting the plug orientation without adding additional physical switches or external buttons.

[0007] This utility model achieves the above objective through the following technical solution: a single-interface USB signal automatic switching circuit, comprising: The Type-C female connector is equipped with a USB data path for USB data transmission and two orientation identification signal input terminals, SBU1 and SBU2. The main control chip has a main control USB data terminal; Image processing chip with image USB data port; The signal switching unit has a common data path, a first data channel, a second data channel, a selection control terminal SEL, and an enable control terminal OE. Specifically, the SBU1 and SBU2 terminals present inverse phase levels on the Type-C female connector side when the Type-C male connector is inserted correctly and incorrectly, so that the level of the SBU1 terminal has two states and serves as a selection signal. The level of the SBU1 terminal is divided or limited and then used as a selection signal input to the selection control terminal SEL. The enable control terminal OE is grounded through a pull-down resistor to maintain default validity. The signal switching unit is used to connect the USB data path to the host USB data terminal when the selection signal is in the first state, and to connect the USB data path to the image USB data terminal when the selection signal is in the second state.

[0008] In this case, a voltage-sharing resistor circuit was added inside the Type-C male connector of the AC data cable: one end is connected to a 5V power supply, the other end is grounded, and the midpoint outputs approximately a 2V control level. This output is fixedly connected to the SBU1 solder point on one side of the male connector during soldering, while the SBU2 solder point on the other side of the male connector is directly grounded.

[0009] Therefore, the male connector internally configures one side of the solder joint to output a high level as a voltage divider, and the other side to output a low level as ground. When the male connector is inserted correctly, the female connector SBU1 terminal is connected to the ground side solder joint and is at a low level, while the female connector SBU2 terminal is connected to the voltage divider side solder joint and is at a high level. When the male connector is inserted incorrectly, the connection relationship is reversed, with the female connector SBU1 terminal at a high level and the female connector SBU2 terminal at a low level. This creates complementary voltage levels in the two insertion states, which drive the selection terminal to select the channel.

[0010] Specifically, both the Type-C male connector and the Type-C female connector have two spare pins, SBU1 and SBU2. The SBU1 and SBU2 solder points on the male connector are located on opposite sides of the connector. When the male connector is inserted correctly, the SBU1 pin of the female connector is connected to the SBU2 solder point of the male connector, and the SBU2 pin of the female connector is connected to the SBU1 solder point of the male connector. When the male connector is inserted incorrectly, this connection is reversed.

[0011] The male connector has an internal voltage divider resistor circuit. One solder joint (SBU1 solder joint) outputs a high level of approximately 2V after voltage division, while the other solder joint (SBU2 solder joint) is grounded. Therefore, in the correct insertion position, the female connector SBU1 terminal is grounded and has a low level, while the female connector SBU2 terminal outputs a high level. In the reverse insertion position, the connections are reversed, and the female connector SBU1 terminal outputs a high level, while the female connector SBU2 terminal is grounded and has a low level. Thus, the female connector SBU1 and SBU2 terminals exhibit complementary voltage levels, i.e., they are in opposite phase, depending on whether they are inserted correctly or incorrectly.

[0012] Furthermore, the selection signal is in a first state when the SBU1 terminal is high and the SBU2 terminal is low, and in a second state when the SBU1 terminal is low and the SBU2 terminal is high.

[0013] Furthermore, the signal switching unit is a dual-channel USB switch with a common data path and two data channels. The common data path is electrically connected to the USB data path of the Type-C female connector, one of the data channels is electrically connected to the main control USB data terminal, and the other data channel is electrically connected to the image USB data terminal.

[0014] Furthermore, the signal switching unit has a common data path and a first data channel, a second data channel, a selection control terminal SEL, and an enable control terminal OE. The enable control terminal OE is grounded via a pull-down resistor to maintain default validity. The common data path is electrically connected to the USB data path. The selection control terminal SEL is used to receive the selection signal to conduct the first data channel when the selection signal is in a first state, so as to connect the USB data path and the host USB data terminal. When the selection signal is in a second state, the second data channel is conducted to connect the USB data path and the image USB data terminal.

[0015] Furthermore, the main control chip is a BES2800 chip, the image processing chip is a Sigma309 chip, and the signal switching unit includes a DIO32320 switch switching chip; A limiting circuit or a voltage divider circuit is provided between the SBU1 terminal and the selection signal input node to limit the input level to a control level not higher than 3.3V; The Type-C female connector has a configuration channel CC line circuit, which includes a CC1 terminal and a CC2 terminal. The CC1 terminal and the CC2 terminal are respectively grounded through a 5.1kΩ pull-down resistor to limit the 5V-1A power supply protocol signal. Specifically, it forms a default 5V-1A power supply protocol signal in the plugged-in state and prevents high voltage fast charging input. The power pin VBUS of the Type-C female connector is connected to the power input VSYS via overvoltage and overcurrent protection devices to improve power supply safety.

[0016] A Type-A to Type-C data cable with direction recognition level output, used in any of the preceding single-interface USB signal automatic switching circuits; The data cable includes a Type-A plug and a Type-C male connector; The Type-C male connector is equipped with a voltage divider resistor circuit, which is used to make the SBU1 terminal on the Type-C female side that is connected to the Type-C male connector high level and the SBU2 terminal on the Type-C female side that is connected to the Type-C male connector low level when the connector is inserted in the correct orientation; and to make the SBU1 terminal low level and the SBU2 terminal high level when the connector is inserted in the reverse orientation. The output level of the voltage divider resistor circuit is limited to a control level not higher than 3.3V.

[0017] Furthermore, the voltage divider resistor circuit is composed of a first resistor and a second resistor connected in series, with the upper end connected to the positive terminal of the power supply and the lower end grounded, and the output is sent to the SBU1 terminal at the connection node of the two resistors. The resistance ratio of the voltage divider circuit is configured to output a control level of no more than 3.3V within the Type-C male connector with a target tolerance to adapt to the input level range of the signal switching unit.

[0018] A Type-C single-interface electronic device, comprising: The data cable features a Type-A plug and a Type-C male connector with an internal voltage divider resistor circuit. The Type-C female connector is equipped with a USB data path for USB data transmission and two orientation identification signal input terminals, SBU1 and SBU2. The main control chip has a main control USB data terminal; Image processing chip with image USB data port; The signal switching unit has a common data path, a first data channel, a second data channel, a selection control terminal SEL, and an enable control terminal OE. Specifically, the SBU1 and SBU2 terminals present inverse phase levels on the Type-C female connector side when the Type-C male connector is inserted correctly and incorrectly, so that the level of the SBU1 terminal has two states and serves as a selection signal. The level of the SBU1 terminal is divided or limited and then used as a selection signal input to the selection control terminal SEL. The enable control terminal OE is grounded through a pull-down resistor to maintain default validity. The signal switching unit is used to connect the USB data path to the host USB data terminal when the selection signal is in the first state, and to connect the USB data path to the image USB data terminal when the selection signal is in the second state.

[0019] Furthermore, the signal switching unit has a common data path and a first data channel, a second data channel, a selection control terminal SEL and an enable control terminal OE. The enable control terminal OE is grounded via a pull-down resistor to maintain default validity. The selection control terminal SEL is used to receive the selection signal to enable the first data channel when the selection signal is in a first state, and to enable the second data channel when the selection signal is in a second state.

[0020] Work process: The different orientations of the Type-C male connector cause the voltage levels of the SBU1 and SBU2 terminals of the Type-C female connector to be different. When the SBU level is different, the DIO32320 switching chip receives different control signals. Switch the chip identification signal to automatically switch the USB data channel (first data channel, second data channel). USB data channel switching allows the computer to switch between different chips inside the AI ​​camera via data cable, i.e., switching between the main control chip and the image processing chip. Engineers simply changed the orientation of the Type-C male connector, and the internal USB path of the AI ​​camera automatically changed.

[0021] The entire process is fully automated, requiring no manual actions such as wire bonding, soldering, or plugging / unplugging.

[0022] The beneficial effects of this utility model are: This invention establishes an anti-phase relationship between the SBU1 and SBU2 terminals of the Type-C female connector, and uses the level of the SBU1 terminal as a selection signal input switching unit, enabling the USB data path to automatically correspond to different chips regardless of whether the plug is inserted in the correct orientation. Compared with traditional methods that rely on jumpers, flying wires, or manual switching, this solution eliminates the need for additional physical switches and manual intervention, and can automatically switch the USB signal path between the main control chip and the image processing chip, fundamentally eliminating signal interference and poor contact problems caused by manual wiring.

[0023] The signal switching unit adopts a dual-channel analog switch structure with a common path. Its selection control terminal SEL automatically activates different channels in response to changes in the SBU level, while the enable control terminal OE remains grounded via a pull-down resistor and remains valid by default, allowing the system to operate stably without additional control logic. By incorporating a voltage divider resistor circuit inside the Type-C male connector, complementary high and low control levels can be output for both positive and negative insertion, providing a reliable direction identification signal to the female connector. The level range is limited to a safe interval, ensuring compatibility with the input thresholds of different chips.

[0024] Meanwhile, the CC1 and CC2 terminals of the Type-C female connector are grounded via 5.1kΩ pull-down resistors to comply with the 5V1A power supply specification and avoid high-voltage input during fast charging. The overall circuit structure is simple and can be directly integrated onto the motherboard, enabling automatic switching of the USB data path between the two chips under a single Type-C interface. This improves debugging efficiency and overall device stability, making it particularly suitable for space-constrained AI cameras and other multi-chip embedded devices. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the principle of this utility model.

[0026] Figure 2 This is the circuit schematic diagram of this utility model, where J23 is the circuit schematic diagram of the Type-C female connector.

[0027] Figure 3 This is the circuit schematic diagram of the Type-C male connector of this utility model. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It is understood that the accompanying drawings are provided for reference and illustration only, and are not intended to limit the present invention. The connection relationships shown in the accompanying drawings are only for clear description and do not limit the connection method.

[0029] like Figures 1-3 As shown, this embodiment of the invention provides a single-interface USB signal automatic switching circuit, a data cable, and an electronic device. It includes: The data cable features a Type-A plug and a Type-C male connector with an internal voltage divider resistor circuit. The Type-C female connector is equipped with a USB data path for USB data transmission and two orientation identification signal input terminals, SBU1 and SBU2. The main control chip has a main control USB data terminal; Image processing chip with image USB data port; The signal switching unit has a common data path, a first data channel, a second data channel, a selection control terminal SEL, and an enable control terminal OE. Specifically, the SBU1 and SBU2 terminals present inverse phase levels on the Type-C female connector side when the Type-C male connector is inserted correctly and incorrectly, so that the level of the SBU1 terminal has two states and serves as a selection signal. The level of the SBU1 terminal is divided or limited and then used as a selection signal input to the selection control terminal SEL. The enable control terminal OE is grounded through a pull-down resistor to maintain default validity. The signal switching unit is used to connect the USB data path to the host USB data terminal when the selection signal is in the first state, and to connect the USB data path to the image USB data terminal when the selection signal is in the second state.

[0030] In this case, a voltage-sharing resistor circuit was added inside the Type-C male connector of the AC data cable: one end is connected to a 5V power supply, the other end is grounded, and the midpoint outputs approximately a 2V control level. This output is fixedly connected to the SBU1 solder point on one side of the male connector during soldering, while the SBU2 solder point on the other side of the male connector is directly grounded.

[0031] Therefore, the male connector internally configures one side of the solder joint to output a high level as a voltage divider, and the other side to output a low level as ground. When the male connector is inserted correctly, the female connector SBU1 terminal is connected to the ground side solder joint and is at a low level, while the female connector SBU2 terminal is connected to the voltage divider side solder joint and is at a high level. When the male connector is inserted incorrectly, the connection relationship is reversed, with the female connector SBU1 terminal at a high level and the female connector SBU2 terminal at a low level. This creates complementary voltage levels in the two insertion states, which drive the selection terminal to select the channel.

[0032] Specifically, both the Type-C male connector and the Type-C female connector have two spare pins, SBU1 and SBU2. The SBU1 and SBU2 solder points on the male connector are located on opposite sides of the connector. When the male connector is inserted correctly, the SBU1 pin of the female connector is connected to the SBU2 solder point of the male connector, and the SBU2 pin of the female connector is connected to the SBU1 solder point of the male connector. When the male connector is inserted incorrectly, this connection is reversed.

[0033] The male connector has an internal voltage divider resistor circuit. One solder joint (SBU1 solder joint) outputs a high level of approximately 2V after voltage division, while the other solder joint (SBU2 solder joint) is grounded. Therefore, in the correct insertion position, the female connector SBU1 terminal is grounded and has a low level, while the female connector SBU2 terminal outputs a high level. In the reverse insertion position, the connections are reversed, and the female connector SBU1 terminal outputs a high level, while the female connector SBU2 terminal is grounded and has a low level. Thus, the female connector SBU1 and SBU2 terminals exhibit complementary voltage levels, i.e., they are in opposite phase, depending on whether they are inserted correctly or incorrectly.

[0034] The technical solution proposed in this utility model stems from the practical difficulties encountered during the debugging phase of an AI camera: both the camera's main control chip, BES2800, and the image processing chip, Sigma309, require programming and data transfer with a computer via a USB interface. However, the product's compact structure only includes one Type-C interface. Traditional methods require manual wiring, soldering, or frequent plugging and unplugging to switch the USB connection between the two chips, which is space-consuming and prone to damaging the solder pads, causing signal interference, and operational delays. Therefore, this solution uses the electrical difference between the forward and reverse orientations of the Type-C plug as the basis for automatic switching, achieving intelligent switching of the USB path without adding any physical switches.

[0035] The Type-C interface has two auxiliary signal lines, SBU1 and SBU2, whose connection positions are interchanged when the plug is inserted in either direction. The inventors utilized this physical characteristic to construct an identification signal path. A voltage divider circuit was set on the small board of the AC data line to reduce the 5V voltage to a stable high level of approximately 2V and output it to SBU1, while SBU2 was grounded. When the plug orientation changes, the SBU1 level detected by the device changes accordingly: low level when inserted correctly and high level when inserted incorrectly. This level change is used as a switching judgment signal (i.e., selection signal). The device is equipped with a switch switching chip DIO32320, whose control terminals SEL and OE respond to this signal to automatically select the USB path. When SBU1 is low and OE remains low, the switch is turned on to channel 1, and the USB signal is connected to the BES2800; when SBU1 is high, channel 2 is selected, and the USB signal automatically switches to the Sigma309. Since both SEL and OE are connected in series with 10kΩ pull-down resistors, the system maintains a low level by default when no wire is plugged in or in normal wire state, ensuring a stable connection to the main chip when the device is powered on.

[0036] Through voltage division and current limiting design, the switching signal voltage is kept below 3.3V, which meets the identification requirements of the control logic without causing overvoltage damage to the switching chip. Meanwhile, 5.1kΩ pull-down resistors are connected to the CC1 and CC2 pins of the Type-C port, limiting the device's default charging protocol to the 5V-1A range and avoiding the high-voltage input risk from fast charging adapters. This series of circuit designs forms a complete logic chain: changes in plug orientation cause changes in the SBU level, changes in the SBU level drive changes in the control terminal state of the switching chip, and changes in the control terminal state guide the automatic switching of the USB signal path, thereby achieving automatic switching of the debugging object between the two chips.

[0037] The effect of this design is to realize automatic dual-chip switching without manual operation, which eliminates the cumbersome processes of frequent flying wire, soldering wire, plugging and unplugging in the past, and significantly improves debugging efficiency and circuit reliability. The entire system completes automatic identification and switching of the USB signal path only through the orientation of the plug, which not only simplifies the structural layout, but also ensures signal integrity and level safety. For AI camera products with limited space and limited interfaces, this solution has significant practical value in saving structural space, improving development efficiency and ensuring system stability.

[0038] In one embodiment, the product mainboard is provided with a Type-C female socket, the SBU1 terminal and SBU2 terminal of the Type-C female socket are led out and connected to the selection control terminal SEL, a current-limiting resistor is connected in series between the selection control terminal SEL and the ground to limit the injection current and improve the spike resistance, with a resistance value in the range of 100Ω to 220Ω; the enable control terminal OE is connected to the ground through a pull-down resistor to form a stable default state, with a resistance value of 10kΩ; the dual-channel USB switch is provided with two data channels, leading out a first USB signal port and a second USB signal port, the first USB signal port is connected to the main control USB data terminal of the main control chip, the second USB signal port is connected to the image USB data terminal of the image signal processing chip, and electrostatic protection devices are connected in parallel on the USB signal path to improve electrostatic resistance; CC1 and CC2 of the Type-C female socket are respectively connected to the ground through 5.1kΩ pull-down resistors, so as to limit the charging capability to 5V-1A. The A-C data cable matched with the product is provided with a small board, on which a voltage dividing circuit is formed by a first resistor and a second resistor connected in series, and a defined level of about 2V is obtained by voltage division from 5V, the defined level is connected to SBU1 of the Type-C male plug, and SBU2 of the male plug is connected to the ground. Under this structure, when the A-C data cable is inserted in the defined forward insertion direction, the corresponding relationship between SBU1 and SBU2 seen by the Type-C female socket on the product side is that SBU1 is grounded and SBU2 is floating, the selection control terminal SEL maintains a low level, and the dual-channel USB switch turns on the first USB signal port to connect the USB to the main control chip; when inserted in the defined reverse insertion direction, the SBU on the product side is reversed, the selection control terminal SEL obtains a defined level of about 2V, and the dual-channel USB switch turns on the second USB signal port to connect the USB to the image signal processing chip. Through the above connection relationship, automatic USB switching between the two chips can be realized without changing the appearance and mechanical structure.

[0039] In another embodiment, the control logic of the dual-channel USB switch is configured such that the first USB signal port is activated when the selection control terminal SEL is low and the enable control terminal OE is low; the second USB signal port is activated when the selection control terminal SEL is high and the enable control terminal OE is low; and both channels are deactivated when the enable control terminal OE is high. Thus, a stable default channel can be maintained by pulling down the switch when no cable is plugged in or the ordinary data line SBU is floating. A clear switching is achieved when a small board AC data line with a voltage divider is inserted and inserted in a predefined direction. All of the above embodiments can be combined. Figure 1 and Figure 2 Understanding and reproduction.

[0040] In practical applications, the first chip can be a BES2800 main control chip, and the second chip can be a Sigma309 image signal processing chip; alternatively, other chips with equivalent USB interface characteristics can be used. The dual-channel USB switch can be an analog switch model with selection and enable control terminals, such as the DIO32320 switch chip. The limited level of the voltage divider circuit output can be set within the range of 2V to 2.2V to meet the control threshold requirements. This invention is not limited to a specific chip model; as long as the above-described structural connection and control relationship are met, the same technical effect can be achieved.

[0041] In detail: The implementation principle of this case: 1. Both control pins of the USB switch U9018 are grounded, and the USB is connected to the main control chip BES2800 by default; 2. Connect the SBU1 pin of the modified data cable's Type-C male connector to the middle of the 5V voltage divider circuit to obtain voltage; 3. Define SBU1 as reverse insertion when connected to the switch and SBU2 as normal insertion when connected to the switch.

[0042] 4. When inserted correctly, SBU2 connects to a control pin of the switching chip. At this time, both control pins are still low, and the switching switch is switched to the main control chip BES2800. When inserted incorrectly, SBU1 connects to SEL in the control pin of the switching switch. At this time, one of the two control pins of the switching switch is high and the other is low, and the switching switch is switched to the image processing chip Sigma309, realizing automatic switching between the USB of the two ICs to the USB of Type-C when inserted correctly or incorrectly.

[0043] The beneficial technical effects of this utility model are: This invention modifies the SBU1 and SBU2 pins of the AC data cable, and uses a switch to automatically switch the USB signal between the two ICs by reversing the plug. This greatly reduces the time engineers spend on jumper wires during debugging, and also reduces the time software engineers have to identify the signals corresponding to different jumper wires when jumper wires touch the motherboard and cause abnormalities or unstable USB signals.

[0044] Implementation methods and specific implementation principles: Combination Figure 1 and Figure 2 To explain This AI camera product uses two main ICs together to achieve functions such as taking photos and recording videos: the main control chip BES2800 and the image processing chip Sigma309. The BES2800 is the main IC, mainly used for implementing functions such as WIFI / BT / MIC / SPK, while the Sigma309 is an ISP chip that can receive MIPICSI signal input. The BES2800 does not support this, so it is used in conjunction with the Sigma309 to take photos and record videos, and then transmit the data to the BES2800 via SPI. The BES2800 then transmits the data to the mobile phone via WiFi / BT.

[0045] During debugging, the BES2800 needs to transfer files to a computer via USB or import files via USB. The Sigma309 needs to use USB for firmware flashing and file transfer. However, the product only has one Type-C port, which cannot meet the needs of using two USB ports during debugging. Since the debugging of the two ICs is performed separately, the inventor discovered that a switching circuit and a modified AC data cable can be used to switch the USB ports of the two ICs to the product's Type-C interface by allowing reversible insertion.

[0046] pass Figure 1 The block diagram shows the several parts that implement this function: 1. USB switch (including) Figure 2 The switching chip DIO32320, the USB signal of the main control chip BES2800, the USB signal of the image processing chip Sigma309, and the Type-C female connector of the electronic product (see circuit diagram). Figure 2 The J23 connector is the Type-C male connector for the AC data cable, and the small board for the AC data cable is also included. Due to the characteristics of the AC data cable's C port, SBU1 and SBU2 are both unconnected, so we can use these two ports to perform some functions. In combination with the characteristics of the Type-C port, SBU1 and SBU2 only have one pin, so when plugged in the right way or the wrong way, SBU1 and SBU2 will be swapped.

[0047] The upper limit of the switching chip DIO32320 is 3.3V. Therefore, we run a voltage divider circuit on the small board on the AC data line to obtain a 2V voltage that meets the requirements of the DIO32320. Connect this voltage divider to SBU1 and ground SBU2. The two control terminals of DIO32320 are SEL and OE. When both are low, the switch is to channel 1; when SEL is high and OE is low, the switch is to channel 2. When SEL is any level and OE is high, the switch is floating. Utilizing this characteristic, we connect SEL and OE to 10K resistors to ground to maintain the default channel 1. Connect SEL to SBU1 of the TYPE-C female connector. Channel 1 is connected to the USB signal of BES2800 (USB_DM USB_DP in the schematic), and channel 2 is connected to the USB signal of Sigma309 (PAD_USB_DP PAD_USB_DM in the schematic).

[0048] Under normal power-on conditions, we plug in a standard USB-C data cable. This case uses the BES2800's USB port (with SBU1 and SBU2 pins of the data cable left floating), consistent with our main IC settings. Using our modified AC data cable, we define connecting SBU1 of the AC data cable to the product's SBU1 as reverse insertion. At this point, the switch's SEL is 2V high and OE is low, switching to channel 2, which corresponds to the Sigma309 signal. When connecting SBU2 to the product's Type-C SBU1, we define it as correct insertion. At this point, both SEL and OE are low, switching to channel 1, which corresponds to the BES2800 signal. Since the product lacks a fast charging protocol, the two CC pins (CC1 and CC2) of the Type-C cable are connected to 5.1K resistors, defaulting to a 5V-1A charging protocol to ground, protecting the product from damage by fast chargers.

[0049] Therefore, we used several circuit components working together to achieve automatic switching of USB signals between BES2800 and Sigma309, perfectly solving the problem of unstable USB signals during product debugging, and reducing the need for motherboard jumpers, time costs, and other benefits.

[0050] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A single-interface USB signal automatic switching circuit, characterized in that, include: The Type-C female connector is provided with a USB data path for USB data transmission and a direction identification signal input terminal SBU1 and SBU2. The SBU1 terminal and the SBU2 terminal are in opposite phase when the Type-C male connector is inserted in the correct direction and in the reverse direction, so that the level of the SBU1 terminal is in two states and serves as a selection signal. The main control chip has a main control USB data terminal; Image processing chip with image USB data port; as well as The signal switching unit is used to connect the USB data path to the host USB data terminal when the selection signal is in the first state, and to connect the USB data path to the image USB data terminal when the selection signal is in the second state.

2. The single-interface USB signal automatic switching circuit according to claim 1, characterized in that, The selection signal is in a first state when the SBU1 terminal is high and the SBU2 terminal is low, and in a second state when the SBU1 terminal is low and the SBU2 terminal is high.

3. The single-interface USB signal automatic switching circuit according to claim 2, characterized in that, The signal switching unit is a dual-channel USB switch with a common data path and two data channels. The common data path is electrically connected to the USB data path, one of the data channels is electrically connected to the main control USB data terminal, and the other data channel is electrically connected to the image USB data terminal.

4. The single-interface USB signal automatic switching circuit according to claim 2, characterized in that, The signal switching unit has a common data path and a first data channel, a second data channel, a selection control terminal SEL, and an enable control terminal OE. The common data path is electrically connected to the USB data path. The enable control terminal OE is grounded via a pull-down resistor to maintain default validity. The selection control terminal SEL is used to receive the selection signal to enable the first data channel when the selection signal is in a first state, and to enable the second data channel when the selection signal is in a second state.

5. The single-interface USB signal automatic switching circuit according to claim 4, characterized in that, The main control chip is a BES2800 chip, the image processing chip is a Sigma309 chip, and the signal switching unit includes a DIO32320 switch switching chip; A limiting circuit or a voltage divider circuit is provided between the SBU1 terminal and the selection signal input node; The Type-C female connector has a configuration channel CC line circuit, which includes a CC1 terminal and a CC2 terminal, and the CC1 terminal and the CC2 terminal are respectively grounded through pull-down resistors; The power pin VBUS of the Type-C female connector is connected to the power input VSYS via overvoltage and overcurrent protection devices to improve power supply safety.

6. A Type-A to Type-C data cable with direction recognition level output, characterized in that, The single-interface USB signal automatic switching circuit according to any one of claims 1 to 5; The data cable includes a Type-A plug and a Type-C male connector; The Type-C male connector is equipped with a voltage divider resistor circuit, which is used to make the SBU1 terminal high and the SBU2 terminal low when inserted correctly; and to make the SBU1 terminal low and the SBU2 terminal high when inserted incorrectly.

7. The Type-A to Type-C data line with direction recognition level output according to claim 6, characterized in that, The voltage divider resistor circuit consists of a first resistor and a second resistor connected in series, with the upper end connected to the positive terminal of the power supply and the lower end grounded. The output is connected to the SBU1 terminal at the connection node of the two resistors. The resistance ratio of the voltage divider circuit is configured to output a control level of no more than 3.3V within the Type-C male connector with a target tolerance, in order to adapt to the input level range of the signal switching unit.

8. A Type-C single-interface electronic device, characterized in that, include: The data cable features a Type-A plug and a Type-C male connector with an internal voltage divider resistor circuit. The Type-C female connector is provided with a USB data path for USB data transmission and a direction identification signal input terminal SBU1 and SBU2. The SBU1 terminal and the SBU2 terminal present inverse phase levels when the Type-C male connector is inserted in the correct direction and in the reverse direction, so that the level of the SBU1 terminal has two states and serves as a selection signal. The main control chip has a main control USB data terminal; Image processing chip with image USB data port; The signal switching unit is used to connect the USB data path to the host USB data terminal when the selection signal is in the first state, and to connect the USB data path to the image USB data terminal when the selection signal is in the second state.

9. The Type-C single-interface electronic device according to claim 8, characterized in that, The signal switching unit has a common data path and a first data channel, a second data channel, a selection control terminal SEL, and an enable control terminal OE. The enable control terminal OE is grounded via a pull-down resistor to maintain default validity. The selection control terminal SEL is used to receive the selection signal to enable the first data channel when the selection signal is in a first state, and to enable the second data channel when the selection signal is in a second state.

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