Interface circuit, circuit board and intelligent tablet computer

Abstract

The embodiment of the utility model discloses an interface circuit, a circuit board and an intelligent tablet. The interface circuit comprises an output module and at least two monostable sub-circuits, the output end of each monostable sub-circuit is connected with the input end of the output module, the grounding end of each monostable sub-circuit is grounded, and the input end of each monostable sub-circuit is used for being connected with a different peripheral interface; each monostable sub-circuit is used for enabling the output end to output a pulse signal with a corresponding pulse width when the corresponding peripheral interface is connected to a peripheral, and the pulse widths of the pulse signals output by the monostable sub-circuits are different; the output module is used for being connected with the master controller and outputting the received pulse signal to the master controller, so that the master controller determines the peripheral interface currently accessed to the peripheral according to the pulse width of the pulse signal, the problem of poor user experience is solved, automatic identification of peripheral insertion of multiple peripheral interfaces can be realized based on a single output interface, and the user experience is improved. And the user experience is improved.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to an interface circuit, circuit board, and smart tablet. Background Technology

[0002] With the continuous development of the electronics industry, intelligent electronic products have entered people's lives, and the variety of products is constantly emerging. As functions continue to expand, the types of peripheral interfaces for electronic products are becoming increasingly diverse. Peripheral interfaces have a plug-and-play function, meaning that plugging in a peripheral signal source can wake up the corresponding functions of the electronic product.

[0003] In the system architecture of electronic products, I / O (input / output) resources are always relatively scarce, especially when the electronic product is in standby mode, the number of available I / O is even smaller. Therefore, in order to save I / O resources, multiple peripheral interfaces are usually associated with one I / O output interface. When a peripheral is plugged into each peripheral interface, a pulse signal is transmitted to the I / O output interface, which then transmits the pulse signal to the main controller to achieve the wake-up function.

[0004] In related technologies, all signal sources can only be woken up through a single IO output interface. However, the main controller cannot distinguish signal sources based on pulse signals, and therefore cannot determine which signal source channel to switch to or which corresponding operating mode to use. Users typically need to manually switch between these operating modes, resulting in a poor user experience. Utility Model Content

[0005] This application provides an interface circuit, circuit board, and smart tablet that can solve the technical problem of poor user experience. It can automatically identify the insertion of peripherals with multiple peripheral interfaces based on a single output interface, thereby improving the user experience.

[0006] This application provides an interface circuit, including: an output module and at least two monostable sub-circuits;

[0007] The output of each monostable sub-circuit is connected to the input of the output module, the ground terminal of each monostable sub-circuit is grounded, and the input terminal of each monostable sub-circuit is used to connect to a different peripheral interface.

[0008] When a peripheral device is connected to the corresponding peripheral interface, each monostable sub-circuit outputs a pulse signal with a corresponding pulse width at its output terminal. The pulse width of the pulse signal output by each monostable sub-circuit is different.

[0009] The output module is used to connect to the main controller and output the received pulse signal to the main controller so that the main controller can determine the peripheral interface of the currently connected peripheral based on the pulse width of the pulse signal.

[0010] As described above, the interface circuit provided in this example can automatically identify the insertion of peripherals with multiple peripheral interfaces based on a single output interface. The main controller jumps to the corresponding signal source channel and switches to the corresponding signal source working mode based on the identified peripheral interface, realizing automatic switching of working modes. Compared with the method in related technologies that requires users to manually switch working modes, this method eliminates the need for users to manually switch working modes, thereby improving the automation and intelligence of working mode switching and thus enhancing the user experience.

[0011] In one embodiment, the monostable sub-circuit includes a monostable trigger, and the trigger threshold of the monostable trigger in each monostable sub-circuit is different;

[0012] The output of the monostable multivibrator is connected to the input of the output module, the ground terminal of the monostable multivibrator is grounded, and the input of the monostable multivibrator is used to connect to the peripheral interface.

[0013] The above-mentioned method can automatically identify the insertion of peripherals with multiple peripheral interfaces based on a single output interface, saving output interface resources and thus saving cost investment.

[0014] In one embodiment, the monostable multivibrator includes: a first capacitor, a first resistor, and a Schmitt trigger;

[0015] The first terminal of the first capacitor is connected to the first terminal of the first resistor and the input terminal of the Schmitt trigger, and the second terminal of the first capacitor is used to connect to the peripheral interface.

[0016] The second terminal of the first resistor is grounded;

[0017] The output of the Schmitt trigger is connected to the input of the output module.

[0018] As described above, by setting a first capacitor, a first resistor, and a Schmitt trigger in the monostable multivibrator, each monostable sub-circuit is configured with a different trigger threshold. When different monostable sub-circuits receive a pulse signal at their input, the output of the Schmitt trigger in each sub-circuit outputs a pulse signal with a different pulse width. This allows the main controller to determine which peripheral interface has been inserted based on the pulse width output by the Schmitt trigger. This achieves automatic identification of peripheral insertion for multiple peripheral interfaces based on a single output interface, saving output interface resources and thus reducing costs.

[0019] In one embodiment, the monostable sub-circuit further includes: a second resistor;

[0020] The first end of the second resistor is connected to the second terminal of the first capacitor, and the second end of the second resistor is grounded.

[0021] As mentioned above, the second resistor provides a default state, which makes it less susceptible to interference signals when the input is floating, thereby improving the reliability of the circuit.

[0022] In one embodiment, the monostable trigger further includes: a first diode;

[0023] The anode of the first diode is connected to the first terminal of the first capacitor;

[0024] The cathode of the first diode is connected to the input of the Schmitt trigger.

[0025] As mentioned above, the first diode prevents negative pulse signals from entering the Schmitt trigger, thereby improving the stability of the Schmitt trigger, protecting the internal circuitry or components of the Schmitt trigger, and thus enhancing the triggering reliability of the Schmitt trigger.

[0026] In one embodiment, the output module includes: an inverting sub-circuit;

[0027] The first terminal of the inverting sub-circuit is connected to the output terminal of the monostable sub-circuit;

[0028] The second terminal of the inverter sub-circuit is grounded;

[0029] The third terminal of the inverter sub-circuit is used to connect the power supply voltage;

[0030] The fourth terminal of the inverter sub-circuit is used to connect to the main controller.

[0031] As mentioned above, since different master controllers may have different trigger pulses, by setting an inverting circuit, the positive pulse is converted into a negative pulse, so that the interface circuit can support more types of master controllers, thereby improving the application diversity of the interface circuit.

[0032] In one embodiment, the inverting sub-circuit includes: a third resistor, a fourth resistor, and a MOSFET;

[0033] The first terminal of the third resistor is connected to the output terminal of the monostable sub-circuit and the gate of the MOSFET;

[0034] The second terminal of the third resistor is grounded to the source of the MOSFET;

[0035] The drain of the MOSFET is connected to the first terminal of the fourth resistor, and the drain of the MOSFET is used to connect to the main controller.

[0036] The second terminal of the fourth resistor is used to connect the power supply voltage.

[0037] As mentioned above, since different master controllers may have different trigger pulses, by setting an inverting circuit, the positive pulse is converted into a negative pulse, so that the interface circuit can support more types of master controllers, thereby improving the application diversity of the interface circuit.

[0038] In one embodiment, the inverting sub-circuit includes: a third resistor, a fourth resistor, and a transistor;

[0039] The first end of the third resistor is connected to the output of the monostable sub-circuit and the base of the transistor;

[0040] The second terminal of the third resistor is grounded to the emitter of the transistor;

[0041] The collector of the transistor is connected to the first end of the fourth resistor, and the collector of the transistor is used to connect to the main controller.

[0042] The second terminal of the fourth resistor is used to connect the power supply voltage.

[0043] As mentioned above, since different master controllers may have different trigger pulses, by setting an inverting circuit, the positive pulse is converted into a negative pulse, so that the interface circuit can support more types of master controllers, thereby improving the application diversity of the interface circuit.

[0044] This application also provides a circuit board including the interface circuit described above.

[0045] This application also provides a smart tablet, including the circuit board described above.

[0046] The beneficial effects of the circuit board and smart tablet provided above can be referenced from the beneficial effects of the interface circuit. Attached Figure Description

[0047] Figure 1 This is a first schematic diagram of an interface circuit provided in an embodiment of this application;

[0048] Figure 2 This is a first schematic diagram of a monostable sub-circuit provided in an embodiment of this application;

[0049] Figure 3 This is a pulse width comparison diagram of a pulse signal provided in an embodiment of this application;

[0050] Figure 4 This is a second schematic diagram of an interface circuit provided in an embodiment of this application;

[0051] Figure 5 This is a third schematic diagram of an interface circuit provided in an embodiment of this application. Detailed Implementation

[0052] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0053] In the system architecture of electronic products, I / O (input / output) resources are always relatively scarce, especially when the electronic product is in standby mode, where the number of available I / O is even smaller. Therefore, to conserve I / O resources, multiple peripheral interfaces typically correspond to one I / O output interface. When a peripheral is plugged into an interface, a pulse signal is transmitted to that I / O output interface, which then transmits the pulse signal to the host controller to achieve the wake-up function. For example, when a peripheral is plugged in, the corresponding I / O output interface outputs a high-level signal or a low-level signal to the host controller to achieve wake-up.

[0054] In related technologies, all signal sources can only be woken up through a single IO output interface. However, the main controller cannot distinguish signal sources based on pulse signals, and therefore cannot determine which signal source channel to switch to or which corresponding operating mode to use. Users typically need to manually switch between these operating modes, resulting in a poor user experience.

[0055] Based on this, the present application provides an interface circuit, circuit board, and smart tablet. The interface circuit, by setting an output module and at least two monostable sub-circuits, connects the output terminal of each monostable sub-circuit to the input terminal of the output module. The input terminal of each monostable sub-circuit is used to connect to a different peripheral interface. When a peripheral is connected to the corresponding peripheral interface, the output terminal of each monostable sub-circuit outputs a pulse signal with a corresponding pulse width to the output module. The output module transmits the received pulse signal to the main controller, allowing the main controller to determine the currently connected peripheral interface based on the pulse width. Using this technique, automatic identification of multiple peripheral interfaces can be achieved based on a single output interface. The main controller, based on the identified peripheral interface, switches to the corresponding signal source channel and the corresponding signal source's operating mode, achieving automatic switching of operating modes. Compared to related technologies that require manual switching of operating modes by the user, this eliminates the need for manual switching, thereby improving the automation and intelligence of operating mode switching and ultimately enhancing the user experience.

[0056] Figure 1 This is a first schematic diagram of an interface circuit provided in an embodiment of this application, referring to... Figure 1The interface circuit 10 includes an output module 11 and at least two monostable sub-circuits 12. The output terminal of each monostable sub-circuit 12 is connected to the input terminal of the output module 11, the ground terminal of each monostable sub-circuit 12 is grounded, and the input terminal of each monostable sub-circuit 12 is used to connect to a different peripheral interface 20. When a peripheral is connected to the corresponding peripheral interface 20, the output terminal of each monostable sub-circuit 12 outputs a pulse signal with a corresponding pulse width. The pulse width of the pulse signal output by each monostable sub-circuit 12 is different. The output module 11 is used to connect to the main controller 30 and outputs the received pulse signal to the main controller 30, so that the main controller 30 can determine the peripheral interface 20 currently connected to the peripheral based on the pulse width of the pulse signal.

[0057] For example, suppose there are two monostable sub-circuits 12. The input of the first monostable sub-circuit 12 is connected to an HDMI interface, and the input of the second monostable sub-circuit 12 is connected to a Type-C interface. When a peripheral device (i.e., an HDMI device) is inserted into the HDMI interface corresponding to the input of the first monostable sub-circuit 12, the output of the first monostable sub-circuit 12 outputs a first pulse signal with a first pulse width to the output module 11, which is then transmitted to the main controller 30. The main controller 30 presets a correspondence between pulse width and peripheral interface 20. Based on the first pulse width of the received first pulse signal, the main controller 30 compares the corresponding pulse width to determine that the peripheral interface 20 into which the peripheral device is currently inserted is an HDMI interface. The main controller 30 can then switch to the signal source channel corresponding to the HDMI interface and switch to the corresponding HDMI operating mode, such as switching to the HDMI display mode.

[0058] For example, when a peripheral device is inserted into the Type-C interface corresponding to the input terminal of the second monostable sub-circuit 12, the output terminal of the second monostable sub-circuit 12 outputs a second pulse signal with a second pulse width to the output module 11, which then transmits the signal to the main controller 30. The main controller 30 has a preset correspondence between pulse width and peripheral interface 20. Based on the second pulse width of the received second pulse signal, the main controller 30 compares the corresponding correspondence to determine that the peripheral interface 20 into which the peripheral device is currently inserted is a Type-C interface. The main controller 30 can then switch to the signal source channel corresponding to the Type-C interface and switch to the corresponding operating mode, such as switching to the Type-C display mode.

[0059] It should be noted that the first pulse width and the second pulse width are different.

[0060] For example, when the peripheral interface 20 corresponding to the monostable sub-circuit 12 is connected to a peripheral device, a pulse signal can be sent from the peripheral device to the input terminal of the monostable sub-circuit 12, or a pulse signal can be sent from the circuit board or electronic device itself to the input terminal of the monostable sub-circuit 12. After the input terminal receives the pulse signal, the output terminal of the monostable sub-circuit 12 outputs a pulse signal with a corresponding pulse width. The pulse width of the pulse signal received at the input terminal of each monostable sub-circuit 12 is the same, but the pulse width of the pulse signal output at the output terminal of each monostable sub-circuit 12 is different, so as to realize the identification of the peripheral interface 20.

[0061] As described above, the interface circuit 10 provided in this example can automatically identify the insertion of peripherals into the multiple peripheral interfaces 20 based on a single output interface. The main controller 30 jumps to the corresponding signal source channel and switches to the corresponding signal source working mode based on the identification of the inserted peripheral interface 20, thereby realizing automatic switching of working modes. Compared with the method in related technologies that requires users to manually switch working modes, this method does not require users to manually switch working modes, thereby improving the automation and intelligence of working mode switching and thus improving the user experience.

[0062] Figure 2 This is a first schematic diagram of a monostable sub-circuit provided in an embodiment of this application, referring to... Figure 2 The monostable sub-circuit 12 includes a monostable multivibrator 121, and the trigger threshold of each monostable multivibrator 121 in the monostable sub-circuit 12 is different. The output terminal of the monostable multivibrator 121 is connected to the input terminal of the output module 11, the ground terminal of the monostable multivibrator 121 is grounded, and the input terminal of the monostable multivibrator 121 is used to connect to the peripheral interface 20. Because the trigger threshold of each monostable multivibrator 121 in the monostable sub-circuit 12 is different, when different peripheral interfaces 20 are connected to peripherals, the corresponding monostable sub-circuit 12 outputs pulse signals with different pulse widths, allowing the main controller 30 to determine which peripheral interface 20 is connected based on the pulse width of the received pulse signal. This embodiment can achieve automatic identification of peripheral insertion of multiple peripheral interfaces 20 based on a single output interface, saving output interface resources and thus saving cost investment.

[0063] Reference Figure 2The monostable multivibrator 121 includes a first capacitor C1, a first resistor R1, and a Schmitt trigger ST1. The first terminal of the first capacitor C1 is connected to the first terminal of the first resistor R1 and the input terminal of the Schmitt trigger ST1. The second terminal of the first capacitor C1 is used to connect to the peripheral interface 20. The second terminal of the first resistor R1 is grounded, and the output terminal of the Schmitt trigger ST1 is connected to the input terminal of the output module 11. As described above, the first capacitor C1, the first resistor R1, and the Schmitt trigger ST1 constitute a differentiating circuit. By setting different trigger thresholds for the Schmitt trigger ST1 in different monostable sub-circuits 12, different pulse widths can be output by each monostable sub-circuit 12 when different peripheral interfaces 20 are connected to peripherals. This allows the main controller 30 to determine which peripheral interface 20 is connected to the peripheral based on the pulse width of the received pulse signal.

[0064] Reference Figure 2 The monostable sub-circuit 12 further includes a second resistor R2. The first terminal of the second resistor R2 is connected to the second terminal of the first capacitor C1, and the second terminal of the second resistor R2 is grounded. The second resistor R2 provides a default state, making it less susceptible to interference signals when the input is floating, thereby improving the reliability of the circuit. The monostable trigger 121 further includes a first diode D1. The anode of the first diode D1 is connected to the first terminal of the first capacitor C1. The cathode of the first diode D1 is connected to the input terminal of the Schmitt trigger ST1. The first diode D1 prevents negative pulse signals from entering the Schmitt trigger ST1, thereby improving the stability of the Schmitt trigger ST1, protecting the internal circuitry or components of the Schmitt trigger ST1, and ultimately improving the triggering reliability of the Schmitt trigger ST1.

[0065] Figure 3 This is a pulse width comparison diagram of a pulse signal provided in an embodiment of this application, with reference to... Figure 2 and Figure 3 When a pulse signal is received at the input terminal of the monostable sub-circuit 12, that is, when the pulse signal is received at the second terminal of the first capacitor C1, a differentiated waveform will be generated at A1 of the monostable sub-circuit 12, as shown in the figure. Figure 3 As shown by curve A1, when the input pulse signal has both a rising edge and a falling edge, a corresponding differential waveform is generated at A1. This waveform is then passed through the Schmitt trigger ST1 after the first diode D1. By setting appropriate thresholds for the first diode D1 and the Schmitt trigger ST1, the waveform triggered by the falling edge is excluded. After shaping, the pulse waveform at A2 of the monostable sub-circuit 12 is obtained, as shown in the figure. Figure 3 As shown by curve A2 in the figure. Figure 3It can be seen that the rising edge of the pulse signal received at the input end of the monostable sub-circuit 12 provided in this embodiment can obtain the output of the pulse signal. For different paths of the monostable sub-circuit 12, by setting different capacitance values of the first capacitor C1, resistance values of the first resistor R1, and trigger thresholds of the Schmitt trigger ST1, pulse signals with different pulse widths can be obtained at the corresponding output at A2.

[0066] Exemplarily, if the threshold set by the Schmitt trigger ST1 remains unchanged and the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1 are increased, the time for A1 to change from a high level to a low level will become longer. For example, before adjustment, the time for the waveform at A1 to change from VH to Vth (the threshold set by the Schmitt trigger ST1) is t1. At this time, when the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1 are increased, the time for the waveform at A1 to change from VH to Vth is t2, and at this time t2 > t1. Therefore, the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1 in different paths of the monostable sub-circuit 12 can be set differently. The main controller 30 can determine which input is triggered based on whether the time for the waveform at A1 to change from VH to Vth is t2 or t1, that is, to determine which peripheral interface 20 corresponding to the input end of which monostable sub-circuit 12 has inserted a peripheral device. Another example is that the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1 remain unchanged, and Vth is adjusted to become smaller to Vth1, that is, the trigger threshold of the Schmitt trigger ST1 is adjusted to be smaller. At this time, the time for the waveform at A1 to change from VH to Vth1 is t3, and at this time t1 < t3. Therefore, different thresholds can be set for the Schmitt trigger ST1 in different paths of the monostable sub-circuit 12. The main controller 30 can determine which input is triggered based on whether the time for the waveform at A1 to change from VH to Vth is t3 or t1, that is, to determine which peripheral interface 20 corresponding to the input end of which monostable sub-circuit 12 has inserted a peripheral device. Therefore, for different paths of the monostable sub-circuit 12, different parameter combinations of the first capacitor C1, the first resistor R1, and the Schmitt trigger ST1 can be set to make the time for VH to Vth of the waveform corresponding to each path different, that is, the pulse widths of the corresponding output pulse signals are different, so that the main controller 30 can determine which input is triggered based on the pulse width of the received pulse signal, that is, to determine which peripheral interface 20 corresponding to the input end of which monostable sub-circuit 12 has inserted a peripheral device.

[0067] As described above, by setting a first capacitor C1, a first resistor R1, and a Schmitt trigger ST1 in the monostable multivibrator 121, each monostable sub-circuit 12 is configured with a different trigger threshold. When different monostable sub-circuits 12 receive a pulse signal at their input, the output of the Schmitt trigger ST1 outputs a pulse signal with a different pulse width. This allows the main controller 30 to determine which peripheral interface 20 has a peripheral inserted based on the pulse width output by the Schmitt trigger ST1. Automatic identification of peripheral insertion in multiple peripheral interfaces 20 is achieved based on a single output interface, saving output interface resources and thus reducing cost.

[0068] Output module 11 can be a wire, or it can be a contact point where the output terminal of the monostable sub-circuit 12 connects to the main controller 30. The input terminal of output module 11 is connected to the output terminals of all monostable sub-circuits 12. When output module 11 is a wire, the output terminals of all monostable sub-circuits 12 are connected to the main controller 30 via wires.

[0069] Figure 4 This is a second schematic diagram of an interface circuit provided in an embodiment of this application, referring to... Figure 4 The output module 11 may also include an inverting sub-circuit 111. The first terminal of the inverting sub-circuit 111 is connected to the output terminals of all monostable sub-circuits 12, the second terminal of the inverting sub-circuit 111 is grounded, the third terminal of the inverting sub-circuit 111 is used to connect to the power supply voltage, and the fourth terminal of the inverting sub-circuit 111 is used to connect to the main controller 30. Since different main controllers 30 may correspond to different trigger pulses, by setting up the inverting circuit, positive pulses are converted into negative pulses, enabling the interface circuit 10 to support more types of main controllers 30, thereby improving the application versatility of the interface circuit 10.

[0070] Reference Figure 4 The inverting sub-circuit 111 includes a third resistor R3, a fourth resistor R4, and a MOSFET T1. The first terminal of the third resistor R3 is connected to the output terminal of the monostable sub-circuit 12 and the gate (G) of the MOSFET T1. The second terminal of the third resistor R3 is grounded to the source (S) of the MOSFET T1. The drain (D) of the MOSFET T1 is connected to the first terminal of the fourth resistor R4. The drain (D) of the MOSFET T1 is used to connect to the main controller 30. The second terminal of the fourth resistor R4 is used to connect to the power supply voltage (e.g., +5V). The MOSFET T1 is an N-type MOSFET.

[0071] Figure 5 This is a third schematic diagram of an interface circuit provided in an embodiment of this application, referring to... Figure 5The inverting sub-circuit 111 includes a third resistor R3, a fourth resistor R4, and a transistor T2. The first terminal of the third resistor R3 is connected to the output terminal of the monostable sub-circuit 12 and the base (B) of the transistor T2. The second terminal of the third resistor R3 is grounded to the emitter (E) of the transistor T2. The collector (C) of the transistor T2 is connected to the first terminal of the fourth resistor R4. The collector (C) of the transistor T2 is used to connect to the main controller 30. The second terminal of the fourth resistor R4 is used to connect to the power supply voltage (e.g., +5V). The transistor T2 is an NPN type transistor.

[0072] In one embodiment, in the application of commercial large-screen displays, inserting a device to wake up and jump to the corresponding signal source channel is a very important function. Due to the limited number of connection pins on the motherboard and interface circuit 10, and the limited number of available I / O output interfaces, a wake-up trigger circuit supporting multiple peripheral interfaces 20 inputs is required per output interface (i.e., a single I / O output interface) to enable wake-up functionality even with limited hardware resources. Therefore, this example provides an interface circuit 10, which can be configured with multiple monostable sub-circuits 12. The input of each monostable sub-circuit 12 is connected to a peripheral interface 20. When a peripheral is inserted into the peripheral interface 20, the output of the corresponding monostable sub-circuit 12 outputs a pulse signal with a corresponding pulse width to the output module 11. The output module 11 transmits the received pulse signal to the main controller 30, so that the main controller 30 can determine the currently connected peripheral interface 20 based on the pulse width of the pulse signal.

[0073] For example, suppose the input of a monostable subcircuit 12 is connected to an HDMI interface. When a peripheral device (i.e., an HDMI device) is plugged into the HDMI interface, the input of the monostable subcircuit 12 receives an HDMI_5V pulse signal. This HDMI_5V pulse signal is used to provide a device access signal to the controller of the electronic device (e.g., a display device). The voltage of this HDMI_5V pulse signal is 5V. When no peripheral device (i.e., an HDMI device) is plugged into the HDMI interface, the input of the monostable subcircuit 12 is in a low-level state. After adding an inverting circuit, the output of the monostable subcircuit 12 is in a continuously high-level state. When an HDMI interface is connected to a peripheral device (i.e., an HDMI device), the input of the monostable sub-circuit 12 receives the HDMI_5V pulse signal, and the state of the input of the monostable sub-circuit 12 changes from a low level to a high level. Since the peripheral device (i.e., the HDMI device) is always connected, the input of the monostable sub-circuit 12 will remain at a high level. However, after the Schmitt trigger ST1, a high-level pulse signal (with a certain pulse width) will be generated. After passing through the inverting circuit, it will become a low-level pulse signal (with a certain pulse width). By detecting the pulse width of this pulse signal, the main controller 30 can determine that the corresponding HDMI interface is connected to a peripheral device (i.e., an HDMI device).

[0074] The interface circuit 10 provided in this embodiment can support multi-input status detection when IO resources are limited. It can distinguish different inputs based on the pulse width of the output pulse signal. Using only common components, it can achieve automatic identification of peripheral insertion of multiple peripheral interfaces 20 based on a single output interface, without additional load, thus saving cost. Through the interface circuit 10 provided in this example, automatic identification of peripheral insertion of multiple peripheral interfaces 20 can be achieved based on a single output interface. The main controller 30 jumps to the corresponding signal source channel and switches to the corresponding signal source working mode based on the identification of the inserted peripheral interface 20, realizing automatic switching of working modes. Compared with the method of requiring users to manually switch working modes in related technologies, it eliminates the need for users to manually switch working modes, thereby improving the automation and intelligence of working mode switching and thus improving the user experience.

[0075] This application also provides a circuit board including the aforementioned interface circuit.

[0076] This application also provides a smart tablet, including the aforementioned circuit board. The smart tablet includes the aforementioned interface circuit, peripheral interface, and main controller, etc.

[0077] The beneficial effects of the circuit board and smart tablet provided above can be referenced from the beneficial effects of the interface circuit.

[0078] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0079] In this utility model, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "join," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0081] It should be noted that, in this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0082] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An interface circuit, characterized in that, include: Output module and at least two monostable sub-circuits; The output terminal of each monostable sub-circuit is connected to the input terminal of the output module, the ground terminal of each monostable sub-circuit is grounded, and the input terminal of each monostable sub-circuit is used to connect to a different peripheral interface respectively. When each monostable sub-circuit is used to connect a peripheral device to the corresponding peripheral interface, the output terminal outputs a pulse signal with a corresponding pulse width. The pulse width of the pulse signal output by each monostable sub-circuit is different. The output module is used to connect to the main controller and output the received pulse signal to the main controller so that the main controller can determine the peripheral interface of the currently connected peripheral based on the pulse width of the pulse signal.

2. The interface circuit according to claim 1, characterized in that, The monostable sub-circuit includes a monostable trigger, and the trigger threshold of the monostable trigger in each monostable sub-circuit is different. The output terminal of the monostable multivibrator is connected to the input terminal of the output module, the ground terminal of the monostable multivibrator is grounded, and the input terminal of the monostable multivibrator is used to connect to the peripheral interface.

3. The interface circuit according to claim 2, characterized in that, The monostable multivibrator includes: a first capacitor, a first resistor, and a Schmitt trigger; The first terminal of the first capacitor is connected to the first terminal of the first resistor and the input terminal of the Schmitt trigger, and the second terminal of the first capacitor is used to connect to a peripheral interface. The second terminal of the first resistor is grounded; The output of the Schmitt trigger is connected to the input of the output module.

4. The interface circuit according to claim 3, characterized in that, The monostable sub-circuit further includes: a second resistor; The first end of the second resistor is connected to the second terminal of the first capacitor, and the second end of the second resistor is grounded.

5. The interface circuit according to claim 3, characterized in that, The monostable trigger also includes: a first diode; The anode of the first diode is connected to the first terminal of the first capacitor; The cathode of the first diode is connected to the input terminal of the Schmitt trigger.

6. The interface circuit according to any one of claims 1-5, characterized in that, The output module includes: an inverting sub-circuit; The first terminal of the inverting sub-circuit is connected to the output terminal of the monostable sub-circuit. The second terminal of the inverting sub-circuit is grounded; The third terminal of the inverting sub-circuit is used to connect to the power supply voltage; The fourth terminal of the inverting sub-circuit is used to connect to the main controller.

7. The interface circuit according to claim 6, characterized in that, The inverting sub-circuit includes: a third resistor, a fourth resistor, and a MOSFET; The first end of the third resistor is connected to the output end of the monostable sub-circuit and the gate of the MOS transistor; The second terminal of the third resistor is grounded to the source of the MOS transistor; The drain of the MOS transistor is connected to the first terminal of the fourth resistor, and the drain of the MOS transistor is used to connect to the main controller. The second end of the fourth resistor is used to connect to the power supply voltage.

8. The interface circuit according to claim 6, characterized in that, The inverting sub-circuit includes: a third resistor, a fourth resistor, and a transistor; The first end of the third resistor is connected to the output terminal of the monostable sub-circuit and the base of the transistor; The second terminal of the third resistor is grounded to the emitter of the transistor; The collector of the transistor is connected to the first end of the fourth resistor, and the collector of the transistor is used to connect to the main controller. The second end of the fourth resistor is used to connect to the power supply voltage.

9. A circuit board, characterized in that, Includes the interface circuit described in any one of claims 1-8.

10. A smart tablet, characterized in that, Includes the circuit board as described in claim 9.

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