Interface circuit, electronic equipment and control method of interface circuit

Abstract

The invention provides an interface circuit, electronic equipment and a control method of the interface circuit, the interface circuit is applied to the electronic equipment, the electronic equipment comprises an external interface, the external interface comprises a first pin and a second pin, the working voltage of the first pin is greater than the working voltage of the second pin, and the first pin is connected with the second pin. The interface circuit comprises a voltage reduction module used for reducing the voltage of the first pin; and the overvoltage detection module is used for detecting the voltage of the second pin and controlling the voltage reduction module to reduce the voltage of the first pin when the voltage of the second pin is greater than a first voltage threshold. According to the interface circuit, the problem that a post-stage device of the low-voltage pin is burnt and broken down due to parasitic coupling or short circuit of the high-voltage pin and the low-voltage pin in the interface circuit can be solved, and the reliability of the electronic equipment can be improved.

Description

Technical Field

[0001] This application relates to the field of circuit technologies, and particularly to an interface circuit, an electronic device, and a control method for the interface circuit. Background Art

[0002] The Type-C interface is a new generation of interface introduced according to the universal serial bus (USB) 3.1 standard. It supports plugging in either way, and can achieve functions such as high-current and high-voltage power supply for electronic devices, high-speed data transmission, and video and audio connections. Currently, the Type-C interface has been widely used in various electronic devices such as mobile phones.

[0003] The Type-C interface includes multiple pins such as the VBUS pin, D+ pin, and D- pin. Different pins are used to implement different functions of the electronic device. For example, the VBUS pin is used to implement the charging / discharging function of the electronic device, and the D+ pin and D- pin are used to implement the data transmission function of the electronic device.

[0004] With the continuous development of fast charging technology, the charging voltage of electronic devices has become higher and higher, so the voltage carried by the VBUS pin is also getting larger. For example, in a fast charging scenario, the voltage of the VBUS pin can reach 9V, 12V, or even 20V. During the normal use of the electronic device, it is inevitable that the Type-C interface gets dirty or damp, which may lead to weak short circuits or parasitic coupling channels between the VBUS pin and the D+ / D- pins. At this time, if the electronic device starts high-voltage charging, the high voltage coupled from the VBUS pin may burn out devices such as transient voltage suppressors (TVS) in the subsequent circuit of the D+ / D- pins, affecting the normal use of the electronic device. Summary of the Invention

[0005] Embodiments of this application provide an interface circuit, an electronic device, and a control method for the interface circuit, which can solve the problem that the subsequent devices of the low-voltage pin are burned out or broken down due to parasitic coupling or short circuit between the high-voltage pin and the low-voltage pin in the interface circuit, and can improve the reliability of the electronic device.

[0006] In a first aspect, an interface circuit is provided, which is applied to an electronic device. The electronic device includes an external interface, and the external interface includes a first pin and a second pin. The operating voltage of the first pin is greater than that of the second pin. The interface circuit includes: a step-down module; an overvoltage detection module, configured to detect the voltage of the second pin and control the step-down module to reduce the voltage of the first pin when the voltage of the second pin is greater than a first voltage threshold.

[0007] The interface circuit provided by the embodiment of the present application includes an overvoltage detection module and a step-down module. The step-down module is used to reduce the voltage of the first pin, and the overvoltage detection module is used to detect the voltage on the second pin and can control the step-down module. When it is detected that the voltage on the second pin is greater than the preset first voltage threshold, it indicates that there may be parasitic coupling or short circuit between the first pin and the second pin. At this time, the overvoltage detection module can control the step-down module to act to quickly reduce the voltage on the first pin, so that the coupling voltage (energy) coupled from the first pin to the second pin is also quickly reduced, making the coupling voltage less than the maximum withstand voltage of the device at the subsequent stage of the second pin, realizing overvoltage protection for the device at the subsequent stage of the second pin, and thus effectively reducing or even avoiding the problem that the device at the subsequent stage of the low-voltage pin is burned out or broken down due to parasitic coupling or short circuit between the pins, improving the reliability of the electronic device.

[0008] The interface circuit provided by the embodiment of the present application intervenes in the coupling energy source, so that the energy coupled to the second pin in an abnormal scenario is less than the standard surge model and within the normal operating (bearable) range of the device at the subsequent stage of the second pin, which can effectively reduce the phenomenon that the device at the subsequent stage is burned out or broken down due to overvoltage, ensure that the circuit at the subsequent stage of the second pin does not show abnormalities, thereby improving the usage reliability of the electronic device and enhancing the user experience.

[0009] Optionally, the operating voltage of the first pin can be a voltage range (for example, 5 - 20V), and the operating voltage of the second pin can be a fixed value (for example, 3.3V). At this time, the operating voltage of the first pin is greater than that of the second pin, which can be that the minimum operating voltage of the first pin is greater than the operating voltage of the second pin (i.e., the fixed value).

[0010] Optionally, the operating voltage of the first pin can be a fixed value (for example, 12V), and the operating voltage of the second pin can be a voltage range (for example, 3 - 3.5V). At this time, the operating voltage of the first pin is greater than that of the second pin, which can be that the operating voltage of the first pin (i.e., the fixed value) is greater than the maximum operating voltage of the second pin.

[0011] Optionally, both the first pin and the second pin have their respective operating voltage ranges. The operating voltage of the first pin is greater than that of the second pin, which can be that the maximum operating voltage of the first pin is greater than the maximum operating voltage of the second pin, that is, at this time, there may be partial overlap between the operating voltage range of the first pin and the operating voltage range of the second pin; it can also be that the minimum operating voltage of the first pin is greater than the maximum operating voltage of the second pin, that is, at this time, there is no overlap between the operating voltage range of the first pin and the operating voltage range of the second pin.

[0012] Optionally, the aforementioned first voltage threshold may be greater than the operating voltage of the second pin. With the above arrangement, the scenario where the second pin operates normally can be excluded, avoiding misoperation of the step-down module (such as a subsequent discharge switch). For example, the operating voltage of the second pin may be 3.3V, and this first voltage threshold may be greater than 3.3V, for example, it may be 4V.

[0013] Optionally, the aforementioned first voltage threshold is less than the maximum withstand voltage of the second functional circuit at the rear stage of the second pin. With the above arrangement, effective protection of components such as the second functional circuit can be achieved. For example, the maximum withstand voltage of the second functional circuit is 5V, and this first voltage threshold may be less than 5V, for example, it may be 4.2V or 4.5V.

[0014] Optionally, the step-down module may include any circuit structure capable of reducing the voltage of the first pin, and the step-down module may reduce the voltage of the first pin in any way. For example, the step-down module may include a first functional circuit connected to the first pin, and the first functional circuit may reduce the operating voltage on the first pin, for example, reduce the operating voltage of the first pin to the minimum operating voltage, or not apply an operating voltage to the first pin to make the first pin not work.

[0015] Optionally, the overvoltage detection module may include any circuit module capable of detecting the voltage of the second pin and controlling the step-down module. For example, the overvoltage detection module may include at least one of components such as a voltage-dividing resistor, a comparator, and a logic gate.

[0016] Optionally, the overvoltage detection module may be a pure circuit module. Or the overvoltage detection module may also be a combination of a software module and a hardware module (such as a circuit module), and this software module may be a process or a code program pre-set in a processor.

[0017] For example, the voltage value of the second pin can be detected by a circuit module and sent to the processor. Based on the built-in processing logic (such as a code program), the processor determines that the voltage value is greater than the first voltage threshold. At this time, the processor can send a control instruction to the step-down module to control the step-down module to act to reduce the voltage of the first pin.

[0018] In a possible implementation manner, when the voltage of the second pin is greater than the first voltage threshold, the overvoltage detection module is specifically configured to: control the step-down module to make the first pin enter an abnormal state, so that the electronic device or an external device connected to the external interface reduces the voltage of the first pin based on a preset circuit protection program.

[0019] Circuit protection programs are usually set in electronic devices or external devices. When it is detected that the external interface has an abnormal operation, the voltage on the interface can be reduced in time to protect the external interface, the interface circuit, etc., and improve the reliability of the device. For example, when the status of the VBUS pin is detected to be abnormal, the electronic device or external device can reduce the charging voltage applied to the VBUS pin or stop charging.

[0020] On this basis, the overvoltage detection module can control the buck module to act so that the first pin enters an abnormal state. In this way, when the electronic device or external device detects this abnormal state, it can reduce the voltage of the first pin based on the preset circuit protection program. By making the first pin enter an abnormal state, the present application can use the preset circuit protection program in the device to reduce the voltage of the first pin. The implementation method of making the first pin enter an abnormal state is simple (for example, grounding the first pin), without a complex circuit structure, thereby making the interface circuit have the advantages of simple structure, small number of components, low implementation cost, and small circuit layout area.

[0021] Optionally, for the buck module to make the first pin enter an abnormal state, it can be grounding the first pin, making the voltage on the first pin abnormal (too high or too low), making the current on the first pin abnormal (too large or too small), making the connection between the first pin and the first functional circuit abnormal (for example, the connection is disconnected), making the temperature of the first pin (external interface) too high, etc., but not limited to this.

[0022] Optionally, when the voltage of the second pin is less than the second voltage threshold, the buck module is controlled to make the first pin enter a normal state, and the second voltage threshold is less than the first voltage threshold.

[0023] That is to say, when the voltage of the second pin is less than the second voltage threshold, the buck module can also make the first pin recover from the abnormal state, that is, it can work normally. Through the above settings, after the voltage on the second pin returns to the normal and reasonable range, the first pin can be restored to the normal state, that is, the first pin can normally exercise its corresponding interface function in time, improving the user experience.

[0024] In a possible implementation manner, the buck module includes: a discharge switch, the first end of the discharge switch is used to connect to the first pin, and the second end is used to ground; when the voltage of the second pin is greater than the first voltage threshold, the overvoltage detection module is specifically used to: control the discharge switch to conduct to ground the first pin.

[0025] With the above settings, when the overvoltage detection module detects that the voltage on the second pin is greater than the first voltage threshold, the overvoltage detection module can control the discharge switch to conduct, shorting the first pin to the reference ground to reduce the voltage on the first pin. At this time, since the first pin is abnormally grounded, that is, the state of the first pin is abnormal, it may further prompt the electronic device or an external device (such as a charger) connected to the external interface to actively reduce the voltage of the first pin based on a preset circuit protection program. Furthermore, the coupled voltage (energy) coupled from the first pin to the second pin can be rapidly reduced, thereby achieving overvoltage protection for the devices after the second pin and improving the reliability of the electronic device.

[0026] The interface circuit provided by the embodiments of the present application can make full use of the existing circuit modules in the electronic device. The discharge switch can reuse the switch device that already exists in the current device for overheat protection of the interface. Only by adding an overvoltage detection module can the protection of specific risk scenarios be achieved through system linkage. The above reasons make the interface circuit have the advantages of simple structure, small number of devices, low implementation cost, and small circuit layout area.

[0027] Optionally, a separate switch device can also be additionally provided as the discharge switch for the overvoltage protection of the second pin, that is, the switch device existing for overheat protection is not reused. The present application does not make special limitations on this.

[0028] Optionally, the discharge switch can include any switch device such as a transistor, a field effect transistor, a thyristor, etc. For example, the discharge switch can include a metal oxide semiconductor (MOS) transistor or a triode, etc. The MOS transistor can be, for example, an n-metal oxide semiconductor (NMOS) transistor or a p-metal oxide semiconductor (PMOS) transistor.

[0029] In a possible implementation manner, the overvoltage detection module is further configured to: when the voltage of the second pin is less than the second voltage threshold, control the discharge switch to turn off, and the second voltage threshold is less than the first voltage threshold.

[0030] With the above settings, after the voltage on the second pin returns to the normal and reasonable range, the discharge function of the discharge switch can be timely turned off, enabling the first pin to be used normally, that is, enabling the first pin to normally perform its corresponding interface function in a timely manner, improving the user experience.

[0031] In a possible implementation, the discharge switch includes a Metal-Oxide-Semiconductor (MOS) transistor. The gate of the MOS transistor is connected to the output terminal of the overvoltage detection module. The source of the MOS transistor is grounded, and the drain of the MOS transistor is connected to the first pin.

[0032] MOS transistors have advantages such as low drive power, fast response speed, small size, low cost, and simplicity in use. In the embodiments of the present application, using a MOS transistor as the discharge switch helps simplify the circuit structure, reduce the implementation cost of the interface circuit, and improve the control efficiency of the overvoltage detection module over the discharge switch, ensuring effective protection of the devices at the rear stage of the second pin.

[0033] In a possible implementation, the overvoltage detection module includes a first resistor and a second resistor. The first end of the first resistor is connected to the second pin. The second end of the first resistor is connected in parallel to the first end of the second resistor and the gate of the MOS transistor, and the second end of the second resistor is grounded.

[0034] The overvoltage detection module with the above structure has extremely low cost, which helps reduce the implementation cost of the interface circuit.

[0035] In a possible implementation, the overvoltage detection module includes a comparator. The first input terminal of the comparator is connected to the second pin. The second input terminal of the comparator receives a voltage reference signal, and the output terminal of the comparator is connected to the gate of the MOS transistor.

[0036] In this way, the comparator can control the MOS transistor based on the comparison result between the voltage value of the input signal at the first input terminal (such as the voltage value of the second pin) and the voltage value of the voltage reference signal. For example, when the voltage value of the input signal is greater than the voltage value of the voltage reference signal, the output terminal of the comparator outputs a high-level signal to control the discharge switch to turn on. When the voltage value of the input signal is less than the voltage value of the voltage reference signal, the output terminal of the comparator outputs a low-level signal to control the discharge switch to turn off.

[0037] For example, the rising-edge trigger threshold V1 of the comparator = ref = 4V, that is, the first voltage threshold is 4V. When the voltage value of the input signal at the first input terminal is greater than 4V, the comparator controls the discharge switch to turn on. When the voltage value of the input signal at the first input terminal is less than 4V, the comparator controls the discharge switch to turn off.

[0038] Exemplarily, the first input terminal of the comparator can be directly connected to the second pin. In this case, the voltage value of the input signal at the first input terminal is the voltage value of the second pin. Alternatively, the first input terminal of the comparator can also be connected to the second pin through a resistor voltage divider. In this case, the voltage value of the input signal at the first input terminal is the voltage value after voltage reduction. The embodiments of the present application do not make special limitations on this.

[0039] The overvoltage detection module includes a comparator, which is beneficial for conveniently and flexibly setting the first voltage threshold. The comparator also has advantages such as strong output driving ability, fast response speed, low cost, and being suitable for integrated chips, which is beneficial for simplifying the circuit structure, reducing the implementation cost of the interface circuit, and improving the control efficiency of the overvoltage detection module for the discharge switch, ensuring effective protection of the devices after the second pin.

[0040] Optionally, the comparator can be a hysteresis comparator. The hysteresis comparator can suppress the influence on the output result due to the fluctuation of the input signal (such as reducing generated noise or glitches, etc.), that is, it can avoid the jitter problem and improve the stability and reliability of the overvoltage detection module's control of the discharge switch. In addition, selecting a hysteresis comparator for the overvoltage detection module is also beneficial for conveniently and flexibly setting the aforementioned second voltage threshold.

[0041] For example, the rising edge trigger threshold V1 = ref = 4V of the hysteresis comparator, that is, the set first voltage threshold is 4V, and the falling edge release threshold V2 = V1 - hysteresis voltage 700mV = 3.3V, that is, the second voltage threshold is 3.3V. That is to say, setting the rising edge trigger threshold can achieve setting the first voltage threshold, and setting the hysteresis voltage can achieve setting the second voltage threshold.

[0042] Optionally, the above comparator can also be replaced by other devices such as logic gates. In addition, the general-purpose input / output (GPIO) pins of the SOC can be reused to detect the voltage of the second pin by detecting the high and low levels, and the SOC can further control the discharge switch according to the detection result. At this time, a voltage dividing resistor can be connected in series between the second pin and the SOC according to actual requirements.

[0043] In a possible implementation, the electronic device includes a first functional circuit and a second functional circuit. The interface circuit further includes a first connection path, a second connection path, and a second protection circuit. Wherein, the first end of the first connection path is used to connect to the first pin, and the second end is used to connect to the first functional circuit; the first end of the second connection path is used to connect to the second pin, and the second end is used to connect to the second functional circuit; the second protection circuit is connected to the second connection path and is used to absorb the surge energy entering the second connection path to protect the second functional circuit.

[0044] In a possible implementation, the first voltage threshold is less than the maximum withstand voltage of the second functional circuit.

[0045] Through the above settings, effective protection of components such as the second functional circuit can be achieved. For example, the maximum withstand voltage of the second functional circuit is 5V, and this first voltage threshold can be less than 5V, such as 4.2V or 4.5V.

[0046] In a possible implementation, the second protection circuit includes a second transient voltage suppressor TVS. The first end of the second TVS is connected to the second connection path, and the second end of the second TVS is used to ground.

[0047] Optionally, the first protection circuit includes a first transient voltage suppressor TVS. The first end of the first TVS is connected to the first connection path, and the second end is used to ground.

[0048] In a possible implementation, the external interface is a Type-C interface, the first pin is a VBUS pin, and the second pin is any one of a D+ pin, a D- pin, a CC1 pin, a CC2 pin, an SBU1 pin, and an SBU2 pin.

[0049] In a possible implementation, the overvoltage detection module is integrated inside a charging chip (charger) or a system on chip (SOC).

[0050] In a second aspect, an electronic device is provided, including: an external interface, the external interface includes a first pin and a second pin, and the operating voltage of the first pin is greater than the operating voltage of the second pin; and, the interface circuit provided by any one of the possible implementations in the foregoing first aspect.

[0051] In a third aspect, a control method for an interface circuit is provided, which is applied to an electronic device. The electronic device includes an external interface, and the external interface includes a first pin and a second pin. The operating voltage of the first pin is greater than that of the second pin. The interface circuit includes a step-down module and an overvoltage detection module. The control method includes: the overvoltage detection module detects the voltage of the second pin; when the voltage of the second pin is greater than a first voltage threshold, the overvoltage detection module controls the step-down module to reduce the voltage of the first pin.

[0052] In a possible implementation, the overvoltage detection module controls the step-down module to reduce the voltage of the first pin, including: the overvoltage detection module controls the step-down module to make the first pin enter an abnormal state, so that the electronic device or an external device connected to the external interface reduces the voltage of the first pin based on a preset circuit protection program.

[0053] In a possible implementation, the step-down module includes a discharge switch. The first end of the discharge switch is connected to the first pin, and the second end is grounded. The overvoltage detection module controls the step-down module to reduce the voltage of the first pin, including: the overvoltage detection module controls the discharge switch to conduct to ground the first pin.

[0054] In a possible implementation, the control method further includes: when the voltage of the second pin is less than a second voltage threshold, the overvoltage detection module controls the discharge switch to turn off, and the second voltage threshold is less than the first voltage threshold.

[0055] In a fourth aspect, a computer-readable storage medium is provided. A computer program is stored on the computer-readable storage medium. When the computer program runs on an electronic device, the electronic device is caused to execute the control method provided in any one of the possible implementations in the foregoing third aspect.

[0056] In a fifth aspect, a computer program product is provided, including: computer program code. When the computer program code runs on an electronic device, the electronic device is caused to execute the control method provided in any one of the possible implementations in the foregoing third aspect.

[0057] In a sixth aspect, an electronic device is provided, including: a memory storing instructions; a processor, when the instructions are run by the processor, causing the electronic device to execute the control method provided in any one of the possible implementations in the foregoing third aspect. Description of the Drawings

[0058] Figure 1 It is a schematic structural diagram of the Type-C interface of the electronic device.

[0059] Figure 2 It is a circuit schematic diagram of the Type-C interface and the subsequent circuit in some implementation manners.

[0060] Figure 3 It is a schematic diagram of the standard surge voltage model.

[0061] Figure 4 It is a schematic diagram of the standard surge current model.

[0062] Figure 5 It is a schematic diagram of the operating principle of the TVS.

[0063] Figure 6 It is a schematic diagram of the burning principle of TVS2 on the D+ / D- path.

[0064] Figure 7 It is a schematic diagram of the application scenario of the electronic device provided in the embodiment of the present application.

[0065] Figure 8 It is a schematic diagram of the connection between the electronic device provided in the embodiment of the present application and an external device.

[0066] Figure 9 It is a schematic diagram of an example of the circuit structure of the electronic device provided in the embodiment of the present application.

[0067] Figure 10 It is a schematic diagram of another example of the circuit structure of the electronic device provided in the embodiment of the present application.

[0068] Figure 11 It is a working timing diagram of the overvoltage detection module for protecting the second connection path.

[0069] Figure 12 It is a schematic diagram of an example of the interface circuit provided in the embodiment of the present application.

[0070] Figure 13 It is a schematic diagram of another example of the interface circuit provided in the embodiment of the present application.

[0071] Figure 14 It is a schematic diagram of the overvoltage detection module integrated in the SOC provided in the embodiment of the present application.

[0072] Figure 15 It is a schematic diagram of the overvoltage detection module integrated in the charging chip provided in the embodiment of the present application.

[0073] Figure 16 It is a flowchart of an example of the control method of the interface circuit provided in the embodiment of the present application.

[0074] Figure 17 It is a flowchart of another example of the control method of the interface circuit provided in the embodiment of the present application. Detailed Embodiments

[0075] The following describes in detail the embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application.

[0076] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a connection that can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0077] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "side", "front", "rear", etc. is based on the orientation or positional relationship of the installation, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0078] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0079] The term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0080] Electronic devices such as mobile phones and tablet computers usually have external interfaces for connecting to external devices, such as USB interfaces or Lightning interfaces. The electronic device is connected to the external device through this external interface, so that electrical signals are transmitted between the functional circuits inside the electronic device and the external device to implement the corresponding interface functions, such as implementing a charging function or a data transmission function, etc.

[0081] The Type-C interface is a new generation of interface introduced according to the USB3.1 standard. It supports plugging in either way, enabling functions such as high-current and high-voltage power supply for electronic devices, high-speed data transmission, video and audio connections, etc. That is to say, the Type-C interface can be multiplexed. For example, it can be used as a charging interface and also as a headphone interface. These advantages have led more and more electronic devices to choose the Type-C interface as the external interface.

[0082] The currently used USB transmission protocols include USB2.0, USB3.0, and USB3.1. Different transmission standards correspond to different transmission speeds. Currently, the transmission speed of USB3.1 is higher than that of USB3.0 and USB2.0. The transmission speed of USB2.0 can reach 480 Mbit / s, the transmission speed of USB3.0 can reach 5 Gbit / s, and the higher transmission speed of USB3.1 can reach 10 Gbit / s.

[0083] The Type-C interface includes a Type-C socket (also called receptacle interface or female head) and a Type-C plug (also called plug interface or male head). Electronic devices such as mobile phones usually use the Type-C socket as the external interface for the Type-C plug of external devices or USB data cables to be inserted to achieve the corresponding interface functions. Figure 1 It is a schematic diagram of the structure of the Type-C interface of an electronic device, that is, a schematic diagram of the structure of the Type-C socket.

[0084] Figure 1 It shows each pin defined in the Type-C interface. As Figure 1 shown, the Type-C interface includes two rows of 24 pins in total. One row of pins is labeled A1 to A12, and the other row of pins is labeled B1 to B12. The upper and lower rows of pins are symmetrically arranged about the center, so the function of plugging in either way can be achieved. Each pin corresponds to a corresponding lane. For example, D+ and D- correspond to the USB2.0 data transmission lane. The 24 pins are as follows:

[0085] 4 power pins VBUS, such as Figure 1 A4, A9, B4, B9 shown in

[0086] 4 ground pins GND, such as Figure 1 A1, A12, B1, B12 shown in

[0087] Two pairs of 4 pins D+ / D- for USB2.0 data transmission, such as Figure 1A6, A7, B6, and B7 shown in [the figure]. Among them, each pair of D+ / D- corresponds to a data channel, and D+ and D- are used to transmit a pair of differential signals.

[0088] Eight pins TXx+ / TXx- and RXx+ / RXx- (x represents 1 or 2) for USB3 data transmission, a total of four pairs, as Figure 1 shown by A2, A3, A10, A11, B2, B3, B10, and B11 in [the figure]. Among them, TX represents the data transmission pin, and RX represents the data reception pin. Each pair of TXx+ / TXx- corresponds to a data channel, and TXx+ and TXx- are used to transmit a pair of differential signals. Each pair of RXx+ / RXx- corresponds to a data channel, and RXx+ and RXx- are used to transmit a pair of differential signals. It should be noted that USB3 here can include USB3.0 and USB3.1.

[0089] Two configuration channel (CC) pins CC1 and CC2, as Figure 1 shown by A5 and B5 in [the figure]. The CC pins (or CC channels) are used to confirm the transmission direction and the correct / incorrect insertion during the Type-C connection process, and are also used to transmit the USB PD BCM code signal to implement the function configuration of the load. When one of the CC pins is used to transmit the configuration signal of the Type-C interface, the other CC pin serves as the power supply VCONN for the electronically marked cable (E-Marker) chip on the cable. The cable with an E-Marker chip can read information such as the current-carrying capacity, characteristics, and wire identification of the cable for transmission configuration.

[0090] Two Type-C extension pins SBU1 and SBU2, as Figure 1 shown by A8 and B8 in [the figure]. SBU1 and SBU2 are transmission channels for auxiliary signals and have different uses in different application scenarios. For example, when transmitting DP signals in the DP alternate mode (DP ALT MODE), they serve as the audio data transmission channel, and in the audio adapter accessory mode, they serve as the microphone signal transmission channel.

[0091] Figure 2 is a circuit schematic diagram of the Type-C interface and the subsequent circuit in some implementation manners. As Figure 2As shown, the Type-C interface is usually set on the outer wall of the electronic device, and the port faces outward for external devices to plug in. Each pin inside the Type-C interface is electrically connected to the corresponding functional circuit inside the electronic device through the corresponding connection path to achieve its own functions. For example, the VBUS pin is electrically connected to the charging chip through connection path #1 to achieve the charging / discharging function of the electronic device; the D+ / D- pins are electrically connected to the SOC through connection path #2 to achieve the data transmission function of the electronic device; the GND pin is electrically connected to the reference ground through connection path #3.

[0092] In the field of electricity, surge is a common phenomenon. Surge can also be called spike, mainly referring to the momentary overvoltage exceeding the normal operating voltage on an electronic device or circuit. During the process of connecting to an external device through an external interface, for example, when plugging or unplugging the external interface to achieve electrical connection or disconnection, there may be a surge entering the external interface. In this way, the surge will further enter the interior of the electronic device through the external interface, causing the subsequent circuit of the external interface to generate an electrical over stress (EOS) phenomenon, which may damage the subsequent circuit.

[0093] Figure 3 It is a schematic diagram of the standard surge voltage model. Figure 4 It is a schematic diagram of the standard surge current model. Combining Figure 3 and Figure 4 , the momentary overvoltage and momentary overcurrent caused by the surge act on the subsequent circuit of the external interface. The transient overvoltage and overcurrent quickly increase from small to large and reach the peak value, and then start to decline. This process lasts for about dozens of microseconds (μs). The momentary overvoltage generated by the surge is much greater than the working voltage of the subsequent circuit and may be greater than the maximum withstand voltage of the electronic components in the subsequent circuit, causing the subsequent circuit to generate an EOS phenomenon, resulting in the electronic components in the subsequent circuit being burned or broken down, affecting the normal use of the external interface or the electronic device.

[0094] For example, when the electronic device is in the process of wired charging through the Type-C interface shown in Figure 2 , at the moment when the charging plug is inserted into the Type-C interface, or at the moment when the charging plug suddenly falls off from the Type-C interface, a surge may be generated. The surge enters the interior of the electronic device through the VBUS pin, which may damage components such as the charging chip in the subsequent circuit.

[0095] For another example, when the electronic device is in Figure 2During the data transmission process through the Type-C interface shown, surges may occur when the plug of an external device is inserted into the Type-C interface or when the plug suddenly falls off the Type-C interface. The surges enter the interior of the electronic device through the D+ / D- pins and may damage components such as the SOC in the subsequent circuit.

[0096] In the current technology, to reduce the damage of surges to the subsequent circuit of the external interface, a TVS is usually set on the subsequent circuit. The TVS can timely discharge the surge current and can effectively protect against EOS, achieving overvoltage protection for the electronic components in the subsequent circuit.

[0097] TVS is a device made of semiconductor technology, integrated with a single PN junction or multiple PN junctions, and is divided into unidirectional and bidirectional types. Unidirectional TVS is generally applied to DC power supply circuits, and bidirectional TVS is applied to circuits with alternating voltages. Figure 5 It is a schematic diagram of the operating principle of TVS. As Figure 5 shown, when applied to a DC circuit, the unidirectional TVS is reversely connected in parallel to the circuit. When the circuit is operating normally, the TVS is in the cut-off state (high impedance state) and does not affect the normal operation of the circuit. When an abnormal overvoltage occurs in the circuit and reaches the breakdown voltage (VBR) of the TVS, the TVS quickly changes from the high-resistance state to the low-resistance state, discharging the instantaneous overcurrent caused by the abnormal overvoltage to the ground, and at the same time clamping the abnormal overvoltage to a lower level, that is, clamping it to the maximum clamping voltage (VC), thus protecting the subsequent protected circuit from damage by the abnormal overvoltage. When the abnormal overvoltage disappears, the resistance value of the TVS returns to the high-impedance state.

[0098] TVS has various different VC specifications, and the selection is specifically based on the voltage withstand specifications of the subsequent circuit and components, that is, it is required that the VC of the TVS is less than the maximum voltage that the subsequent circuit and components can withstand (i.e., the highest voltage withstand). That is to say, the selected VC of the TVS should be less than the highest voltage withstand of the subsequent circuit, so as to effectively achieve EOS protection for the subsequent circuit.

[0099] With the continuous development of fast charging technology, the charging voltage of electronic devices has become higher and higher, so the voltage carried by the VBUS pin of the Type-C interface of the electronic device is also getting larger. For example, in a fast charging scenario, the voltage of the VBUS pin is increased as required and can usually reach 9V, 12V or even 20V. The D+ pin and the D- pin are connected to the SOC, and the maximum operating voltage is usually 3.3V. With the evolution of the SOC process and the USB protocol, the operating voltage of the D+ pin and the D- pin has a further downward trend. Since the typical operating voltage scenarios of the VBUS pin and the D+ / D- pins are different, the withstand voltage specifications of the subsequent device designs are also different. For example, the withstand voltage level of the VBUS port of a general charging chip can reach 24V, and the maximum withstand voltage of the D+ / D- port of the SOC does not exceed 5V. On this premise, the VC specifications of the TVS corresponding to the above two paths or links will also be significantly different.

[0100] Specifically, as Figure 2 shown, the VBUS pin is electrically connected to the charging chip through connection path #1. One end of TVS1 is connected to connection path #1 (i.e., between the VBUS pin and the charging chip), and the other end is grounded. TVS1 is used to protect the subsequent charging chip. Since the maximum withstand voltage of the charging chip is 24V, the VC of TVS1 can be less than and close to 24V. For example, the VC of TVS1 can be 22V or 23V. In this way, when a surge enters connection path #1 through the external interface, TVS1 can clamp the abnormal overvoltage to VC, that is, clamp it to 22V or 23V. Since the VC of TVS1 is less than the maximum withstand voltage of the charging chip, the subsequent charging chip is protected.

[0101] The D+ / D- pins are electrically connected to the SOC through connection path #2. One end of TVS2 is connected to connection path #2 (i.e., between the D+ / D- pins and the SOC), and the other end is grounded. TVS2 is used to protect the subsequent SOC. Since the maximum withstand voltage of the SOC is 5V, the VC of TVS2 can be less than and close to 5V. For example, the VC of TVS2 can be 4V or 4.5V. In this way, when a surge enters connection path #2 through the external interface, TVS2 can clamp the abnormal overvoltage to VC, that is, clamp it to 4V or 4.5V. Since the VC of TVS2 is less than the maximum withstand voltage of the SOC, the subsequent SOC is protected.

[0102] In addition, since the Type-C interface of the electronic device is prone to water ingress or foreign objects, resulting in abnormal charging and an increase in the interface temperature, it may cause the port to burn and deform during charging or even lead to a fire accident. To improve charging safety, as Figure 2As shown, a discharge switch electrically connected to the VBUS pin is usually provided in the electronic device. The main function of the discharge switch is to prevent the interface from overheating and burning. The discharge switch is controlled by the SOC. In the charging scenario, when the system detects that the interface is overheated and comprehensively judges that there is a risk of burning, the SOC sends a signal to control the discharge path to conduct, so that the VBUS pin is short-circuited to the ground. This behavior further triggers the charging chip to detect an abnormality and quickly shut down the VBUS pin output, thereby exiting the charging mode and achieving overheat protection.

[0103] During the normal use of electronic devices, it is inevitable that the Type-C interface will become dirty or damp, which will cause a weak short circuit between the VBUS pin and the D+ / D- pin or a parasitic coupling channel. Figure 6 This is a schematic diagram of the process of weak short circuit or parasitic coupling between the VBUS pin and the D+ / D- pin. Figure 6 As shown in the figure, when the interface is dirty or damp, the VBUS pin and the D+ / D- pin generate a weak short circuit or parasitic coupling. At this time, if the electronic device starts high-voltage charging, the voltage coupled from the VBUS pin is much higher than the clamping voltage of TVS2 on the D+ / D- path, causing TVS2 to be broken down or overheated and burned, thereby affecting the normal use of the electronic device.

[0104] In view of the above problems, an embodiment of the present application provides an interface circuit, which is applied to an electronic device with an external interface, and is used to realize an electrical connection between the external interface and a functional circuit in the device, wherein the external interface includes a first pin and a second pin, and the working voltage of the first pin is greater than that of the second pin. The interface circuit includes a step-down module and an overvoltage detection module, wherein the step-down module is used to reduce the voltage of the first pin, and the overvoltage detection module is used to detect the voltage on the second pin. When it is detected that the voltage on the second pin is greater than a preset first voltage threshold, the overvoltage detection module can also control the step-down module to reduce the voltage on the first pin.

[0105] When the overvoltage detection module detects that the voltage on the second pin is greater than the first voltage threshold, it indicates that parasitic coupling or short circuit may occur between the first pin and the second pin. At this time, the overvoltage detection module can control the step-down module to act to quickly reduce the voltage on the first pin, thereby rapidly reducing the coupling voltage (energy) coupled from the first pin to the second pin, so that the coupling voltage is less than the maximum withstand voltage of the subsequent device of the second pin, thereby achieving overvoltage protection for the subsequent device of the second pin, thereby effectively reducing or even avoiding the problem of burning and breakdown of the subsequent device of the low-voltage pin caused by parasitic coupling or short circuit between the pins, thereby improving the reliability of the electronic equipment.

[0106] In some examples, the overvoltage detection module here may include a discharge switch. One end of the discharge switch is electrically connected to the first pin, and the other end is grounded. The overvoltage detection module can control the on / off of the discharge switch. When the overvoltage detection module detects that the voltage on the second pin is greater than the first voltage threshold, the overvoltage detection module can control the discharge switch to conduct, so that the first pin is shorted to the reference ground to reduce the voltage on the first pin. At this time, since the first pin is abnormally grounded, that is, the state of the first pin is abnormal, it may further prompt the electronic device or an external device (such as a charger) connected to the external interface to actively reduce the voltage of the first pin based on a preset circuit protection program (similar to the aforementioned overheat protection). Furthermore, the coupled voltage (energy) coupled from the first pin to the second pin can be rapidly reduced, thereby achieving overvoltage protection for the devices after the second pin and improving the reliability of the electronic device.

[0107] Exemplarily, in combination with the foregoing Figure 2 and Figure 6 related content, the electronic device here can be a mobile phone, the external interface can be a Type-C interface, the first pin is the VBUS pin, the second pin is the D+ / D- pin (that is, the second pin is the D+ pin or the D- pin), and the overvoltage detection module includes a discharge switch.

[0108] According to the interface circuit provided by the embodiments of the present application, during the charging process of the mobile phone through the Type-C interface (such as fast charging), the overvoltage detection module detects the voltage on the D+ / D- pins. When the overvoltage detection module detects that the voltage on the D+ / D- pins is greater than a preset threshold (for example, 4V), it indicates that there may be parasitic coupling or short circuit between the VBUS pin and the D+ / D- pins. At this time, the overvoltage detection module can timely control the discharge switch to conduct, so that the VBUS pin is shorted to the reference ground through the discharge switch to reduce the voltage on the VBUS pin. After the charger detects that the state of the VBUS pin is abnormal, it will actively reduce the charging voltage based on the circuit protection program in the current charging protocol, such as turning off the VBUS output. Furthermore, the coupled voltage (energy) coupled from the VBUS pin to the D+ / D- pins is also rapidly reduced, so that the coupled voltage is less than the maximum withstand voltage of devices such as TVS2 and SOC after the D+ / D- pins, achieving overvoltage protection for devices such as TVS2 and SOC, effectively reducing the phenomenon that the above devices are burned out and broken down due to overvoltage, thereby improving the reliability of the electronic device in use and enhancing the user experience.

[0109] For the convenience of understanding, the electronic device with the above interface circuit will be introduced below with reference to the accompanying drawings first. Figure 7 is a schematic diagram of the application scenario of the electronic device provided by the embodiments of the present application. As Figure 7As shown, the application scenario includes an electronic device 100 and an external device 200. Among them, the electronic device 100 has an external interface 110, and the electronic device 100 can be electrically connected to the external device 200 through the external interface 110 to implement corresponding interface functions, such as implementing a charging function or a data transmission function, etc.

[0110] In some examples, the electronic device 100 can be any device with an external interface such as a mobile phone, a tablet computer, a laptop computer, a desktop computer, a television, a vehicle-mounted device, a wearable device, a smart speaker, etc. The mobile phone can be, for example, a conventional straight mobile phone or a foldable mobile phone, such as an up-and-down small foldable mobile phone, a left-and-right inner foldable mobile phone, or a left-and-right outer foldable mobile phone. The wearable device can be, for example, a smart bracelet, a smart watch, a wireless earphone (case), an augmented reality (AR) glasses, an AR helmet, a virtual reality (VR) glasses, or a VR helmet, etc. The embodiments of the present application do not impose special restrictions on the specific form of the electronic device 100. Hereinafter, the electronic device 100 is taken as an example of a mobile phone for illustration.

[0111] In some examples, the external interface 110 of the electronic device 100 can be a USB interface, such as a Type-A interface, a Type-B interface, a Type-C interface, a micro USB interface, or a future new type of USB interface, etc. In addition, the external interface 110 can also be other types of interfaces such as a lightning interface, a board to board connector interface, a subscriber identification module (SIM) card interface, a secure digital (SD) card interface, a network cable interface, a video input / output interface, etc. The embodiments of the present application take the external interface 110 as a Type-C interface for illustration.

[0112] In some examples, the external device 200 can be a power adapter (charger), a USB flash drive, a wired earphone, or any terminal device such as a mobile phone or a computer. For example, the type of the terminal device can be the same as or different from that of the electronic device 100.

[0113] Exemplarily, as Figure 7 shown, the external device 200 can be a power adapter, and the power adapter can have a fast charging function. For example, the maximum charging power of the power adapter can reach 40W, 66W, 88W, 100W, 120W or more. At this time, the external device 200 can quickly charge the electronic device 100 through the charging cable 300.

[0114] In a charging scenario, the charging plug 310 at one end of the charging cable 300 is plugged into the external interface 110 of the electronic device 100, and the other end of the charging cable 300 is connected to the output end of the power adapter, while the input end of the power adapter is connected to the power grid. After the electronic device 100 is successfully connected to the power adapter and the protocol handshake is successful, the power adapter converts the AC voltage provided by the power grid (such as 220V) into a DC voltage (such as 12V, 15V or 20V) that meets the charging requirements of the electronic device 100, and outputs this DC voltage to the electronic device 100, thereby realizing the power supply replenishment of the electronic device 100.

[0115] Figure 8 It is a schematic diagram of the connection between the electronic device 100 and the external device 200 provided by the embodiments of the present application. As Figure 8 shown, the electronic device 100 includes an external interface 110, a functional circuit 130, and an interface circuit 120 for connecting the external interface 110 and the functional circuit 130. When the electronic device 100 is connected to the external device 200 through the external interface 110, electrical signals can be transmitted between the electronic device 100 and the external device 200, thereby realizing interface functions, such as a charging function, and also a file transfer function for transmitting file information such as video files, picture files, and audio files.

[0116] Among them, the functional circuit 130 is an electronic component of the electronic device 100 for processing interface signals. The interface signal refers to the electrical signal transmitted between the external interface 120 and the external device 200 for the electronic device 100 to realize the interface function. It should be understood that the interface signal can include the electrical signal transmitted from the electronic device 100 to the external device 200, and can also include the electrical signal transmitted from the external device 200 to the electronic device 100. Since the interface functions of the electronic device 100 include but are not limited to a charging function and a function of transmitting file information (such as video files, picture files, and audio files), the interface signals that need to be processed by the electronic device 100 include but are not limited to: a charging protocol signal for establishing a charging connection and a charging current signal for realizing charging, a communication protocol signal for establishing a file transfer connection, and the file information to be transmitted, etc. Based on this, the functional circuit 130 of the electronic device 100 can include an SOC, a charging chip, etc.

[0117] In some examples, the external interface 110 may introduce surges to the electronic device 100, and the functional circuit 130 can be a circuit that needs surge protection or EOS protection, that is, the functional circuit 130 can be a protected circuit. At this time, the interface circuit 120 can include surge protection devices such as TVS or EOS protection devices, and the TVS is used to discharge the surge current to protect the backend functional circuit 130 from being damaged by the impact of an instantaneous large current.

[0118] In some examples, the functional circuit 130 may include a chip, a processor, a memory, an integrated circuit (IC), etc. For example, the functional circuit 130 may include chips such as an application processor (AP), a micro-electro-mechanical system (MEMS), a radio frequency chip, and an application specific integrated circuit (ASIC). It should be understood that the above application processor or application specific integrated circuit may be a central processing unit (CPU), a graphics processing unit (GPU), or an artificial intelligence processor in specific applications. For example, it may be a network processing unit (NPU), etc. The memory may be a cache, a random access memory (RAM), a read only memory (ROM), or other memories.

[0119] The circuit structure in the embodiments of the present application will be further described in detail below with reference to the accompanying drawings. Figure 9 It is a schematic diagram of an example of the circuit structure of the electronic device 100 provided by the embodiments of the present application. As Figure 9 shown, in the embodiments of the present application, the external interface 110 of the electronic device 100 includes a first pin and a second pin, the interface circuit 120 includes a first connection path 121 and a second connection path 122, and the functional circuit 130 includes a first functional circuit 131 and a second functional circuit 132.

[0120] Among them, the first end of the first connection path 121 is connected to the first pin, and the second end is connected to the first functional circuit 131, that is, the first pin is connected to the first functional circuit 131 through the first connection path 121 to implement the interface function corresponding to the first pin, such as a charging function. The first end of the second connection path 122 is connected to the second pin, and the second end is connected to the second functional circuit 132, that is, the second pin is connected to the second functional circuit 132 through the second connection path 122 to implement the interface function corresponding to the second pin, such as a data transmission function.

[0121] In some examples, the interface circuit 120 further includes a first protection circuit 125 and a second protection circuit 126. The first protection circuit 125 is connected to the first connection path 121 and is configured to absorb the surge energy entering the first connection path 121, for example, discharging the surge current, so as to protect the first functional circuit 131. The second protection circuit 126 is connected to the second connection path 122 and is configured to absorb the surge energy entering the second connection path 122, for example, discharging the surge current, so as to protect the second functional circuit 132.

[0122] Exemplarily, the protection circuit here (such as the first protection circuit 125 and / or the second protection circuit 126) can be a surge protection circuit or an EOS protection circuit, and can include at least one of a TVS, a gas discharge tube, an over voltage protection (OVP) device, a level shift device, etc., but is not limited thereto.

[0123] Exemplarily, the operating voltage of the first pin is greater than that of the second pin, and the maximum withstand voltage of the first functional circuit 131 can be greater than that of the second functional circuit 132. Therefore, the specifications or grades of the corresponding protection devices in the first protection circuit 125 and the second protection circuit 126 can be different. For example, both the first protection circuit 125 and the second protection circuit 126 include a TVS. Since the maximum withstand voltage of the first functional circuit 131 is greater than that of the second functional circuit 132, the VC of the TVS in the first protection circuit 125 is greater than the VC of the TVS in the second protection circuit 126.

[0124] Exemplarily, the external interface 110 can be a Type-C interface, the first pin can be a VBUS pin, and the second pin can be any one of a D+ pin, a D- pin, a CC1 pin, a CC2 pin, an SBU1 pin, and an SBU2 pin. At this time, the first functional circuit 131 can be a charging chip, and the second functional circuit 132 can be a SOC.

[0125] As Figure 9 shown, the interface circuit 120 further includes an overvoltage detection module 123 and a buck module 124. The buck module 124 is connected to the first pin and is configured to reduce the voltage of the first pin. The input end of the overvoltage detection module 123 is connected to the second pin, and the output end is connected to the buck module 124. The overvoltage detection module 123 is configured to detect the voltage on the second pin. When it detects that the voltage on the second pin is greater than a preset first voltage threshold, the overvoltage detection module 123 can also control the buck module 124 to reduce the voltage on the first pin.

[0126] The interface circuit 120 provided by the embodiment of the present application includes an overvoltage detection module 123 and a step-down module 124. The step-down module 124 is used to reduce the voltage of the first pin, and the overvoltage detection module 123 is used to detect the voltage on the second pin and can control the step-down module 124. When it is detected that the voltage on the second pin is greater than a preset first voltage threshold, it indicates that parasitic coupling or short circuit may occur between the first pin and the second pin. At this time, the overvoltage detection module 123 can control the step-down module 124 to act to quickly reduce the voltage on the first pin, so that the coupled voltage (energy) coupled from the first pin to the second pin is also quickly reduced, making the coupled voltage less than the maximum withstand voltage of the device at the subsequent stage of the second pin, realizing overvoltage protection for the device at the subsequent stage of the second pin, and thus effectively reducing or even avoiding the problem that the device at the subsequent stage of the low-voltage pin is burned out or broken down due to parasitic coupling or short circuit between the pins, improving the reliability of the electronic device 100.

[0127] The interface circuit 120 provided by the embodiment of the present application intervenes in the coupled energy source, so that the energy coupled to the second pin in an abnormal scenario is less than the standard surge model and within the normal operating (bearable) range of the device at the subsequent stage of the second pin, which can effectively reduce the phenomenon that the device at the subsequent stage is burned out or broken down due to overvoltage, ensure that the subsequent circuit of the second pin does not malfunction, thereby improving the usage reliability of the electronic device and enhancing the user experience.

[0128] In some examples, the operating voltage of the first pin can be a voltage range (such as 5 - 20V), and the operating voltage of the second pin can be a fixed value (such as 3.3V). At this time, the operating voltage of the first pin is greater than that of the second pin, which can be that the minimum operating voltage of the first pin is greater than the operating voltage of the second pin (i.e., the fixed value).

[0129] In some examples, the operating voltage of the first pin can be a fixed value (such as 12V), and the operating voltage of the second pin can be a voltage range (such as 3 - 3.5V). At this time, the operating voltage of the first pin is greater than that of the second pin, which can be that the operating voltage of the first pin (i.e., the fixed value) is greater than the maximum operating voltage of the second pin.

[0130] In some examples, both the first pin and the second pin have their respective operating voltage ranges. The operating voltage of the first pin is greater than that of the second pin, which can be that the maximum operating voltage of the first pin is greater than the maximum operating voltage of the second pin, that is, at this time, there may be a partial overlap between the operating voltage range of the first pin and the operating voltage range of the second pin; it can also be that the minimum operating voltage of the first pin is greater than the maximum operating voltage of the second pin, that is, at this time, there is no overlap between the operating voltage range of the first pin and the operating voltage range of the second pin.

[0131] In some examples, the foregoing first voltage threshold may be greater than the operating voltage of the second pin. With the above arrangement, the scenario where the second pin operates normally can be excluded, avoiding misoperation of the buck module 124. For example, the operating voltage of the second pin may be 3.3V, and this first voltage threshold may be greater than 3.3V, for example, it may be 4V.

[0132] In some examples, the foregoing first voltage threshold is less than the maximum withstand voltage of the second functional circuit 132. With the above arrangement, effective protection of components such as the second functional circuit 132 can be achieved. For example, the maximum withstand voltage of the second functional circuit 132 is 5V, and this first voltage threshold may be less than 5V, for example, it may be 4.2V or 4.5V.

[0133] In some examples, the buck module 124 may include any circuit structure capable of reducing the voltage of the first pin, and the buck module 124 may reduce the voltage of the first pin in any manner. For example, the buck module 124 may include a first functional circuit 131 connected to the first pin, and the first functional circuit 131 may reduce the operating voltage on the first pin, for example, reduce the operating voltage of the first pin to the minimum operating voltage, or not apply an operating voltage to the first pin, causing the first pin not to operate.

[0134] In some examples, the overvoltage detection module 123 may include any circuit module capable of detecting the voltage of the second pin and controlling the on / off of the buck module 124. For example, the overvoltage detection module 123 may include at least one of components such as a voltage-dividing resistor, a comparator, and a logic gate.

[0135] In some examples, the overvoltage detection module 123 may be a pure circuit module. Or the overvoltage detection module 123 may also be a combination of a software module and a hardware module (such as a circuit module), and this software module may be a process or a code program pre-set in the processor.

[0136] For example, the voltage value of the second pin may be detected by the circuit module and sent to the processor. Based on the built-in processing logic (such as a code program), the processor determines that the voltage value is greater than the first voltage threshold. At this time, the processor may send a control instruction to the buck module 124 to control the buck module 124 to act to reduce the voltage of the first pin.

[0137] In some examples, the overvoltage detection module 123 is specifically configured to:

[0138] Control the buck module 124 to make the first pin enter an abnormal state, so that the electronic device 100 or the external device 200 connected to the external interface 110 reduces the voltage of the first pin based on a preset circuit protection program.

[0139] A circuit protection program is usually set in the electronic device 100 or the external device 200. When it detects that the external interface 110 has an abnormal operation, it can timely reduce the voltage on the interface to protect the external interface 110, the interface circuit 120, etc., and improve the device reliability. For example, when it detects that the state of the VBUS pin is abnormal, the electronic device 100 or the external device 200 can reduce the charging voltage applied to the VBUS pin, or stop charging.

[0140] On this basis, the overvoltage detection module 123 can control the buck module 124 to act so that the first pin enters an abnormal state. In this way, when the electronic device 100 or the external device 200 detects this abnormal state, it can reduce the voltage of the first pin based on the preset circuit protection program. By making the first pin enter an abnormal state, the present application can use the preset circuit protection program in the device to reduce the voltage of the first pin. And the implementation method of making the first pin enter an abnormal state is simple (for example, grounding the first pin), without a complex circuit structure, thus making the interface circuit 120 have the advantages of simple structure, small number of components, low implementation cost, and small circuit layout area.

[0141] In some examples, for the buck module 124 to make the first pin enter an abnormal state, it can be grounding the first pin, the voltage on the first pin being abnormal (too high or too low), the current on the first pin being abnormal (too large or too small), the connection between the first pin and the first functional circuit 131 being abnormal (such as a disconnection), the temperature of the first pin (external interface 110) being too high, etc., but not limited to this.

[0142] In some examples, when the voltage of the second pin is less than the second voltage threshold, the buck module 124 is controlled to make the first pin enter a normal state, and the second voltage threshold is less than the first voltage threshold.

[0143] That is to say, when the voltage of the second pin is less than the second voltage threshold, the buck module 124 can also make the first pin recover from the abnormal state, that is, it can operate normally. Through the above settings, after the voltage on the second pin returns to the normal and reasonable range, the first pin can be restored to the normal state, that is, the first pin can timely and normally exercise its corresponding interface function, improving the user experience.

[0144] In some examples, the step-down module 124 includes a discharge switch 128. The first end of the discharge switch 128 is connected to the first pin. For example, the first end of the discharge switch 128 is connected to the first connection path 121, that is, the discharge switch 128 can be electrically connected to the first pin through the first connection path 121. The second end of the discharge switch 128 is connected to the reference ground. In this way, when the discharge switch 128 is turned on, the first pin will be shorted to the reference ground through the discharge switch 128.

[0145] The input end of the overvoltage detection module 123 is connected to the second pin. For example, the first end of the overvoltage detection module 123 is connected to the second connection path 122, that is, the overvoltage detection module 123 can be electrically connected to the second pin through the second connection path 122. The output end of the overvoltage detection module 123 is connected to the discharge switch 128 to realize the on-off control of the discharge switch 128.

[0146] In the embodiment of the present application, the overvoltage detection module 123 is used to detect the voltage on the second pin and control the discharge switch 128 to turn on when the voltage on the second pin is greater than a preset first voltage threshold. In this way, the first pin will be shorted to the reference ground through the discharge switch 128.

[0147] Through the above settings, when the overvoltage detection module 123 detects that the voltage on the second pin is greater than the first voltage threshold, the overvoltage detection module 123 can control the discharge switch 128 to turn on, so that the first pin is shorted to the reference ground to reduce the voltage on the first pin. At this time, due to the abnormal grounding of the first pin, that is, the first pin appears in an abnormal state, it may further prompt the electronic device 100 or an external device 200 (such as a charger) connected to the external interface to actively reduce the voltage of the first pin based on a preset circuit protection program (similar to the aforementioned overheat protection). Furthermore, the coupling voltage (energy) coupled from the first pin to the second pin can be quickly reduced, thereby realizing overvoltage protection for the devices at the rear stage of the second pin and improving the reliability of the electronic device.

[0148] The interface circuit 120 provided by the embodiment of the present application can make full use of the existing circuit modules in the electronic device 100. The discharge switch 128 can reuse the switch device already existing in the current device for overheat protection of the interface. Only by adding the overvoltage detection module 123 can the protection of specific risk scenarios be realized through system linkage. The above reasons make the interface circuit 120 have the advantages of simple structure, small number of devices, low implementation cost, and small circuit layout area.

[0149] In some examples, the circuit protection program here can be an output overcurrent protection program, an output short-circuit protection program (which may be triggered when the first pin is grounded, for example), an output overvoltage protection, or an interface overheat protection program, etc., but not limited thereto. When the electronic device 100 or the external device 200 (such as a charger) detects an abnormal state of the first pin, it can trigger the corresponding protection program and reduce the voltage on the first pin based on this program.

[0150] In some examples, a switching device can also be separately provided as a discharge switch 128 specifically for the overvoltage protection of the second pin, that is, the existing switching device for overheat protection is not reused. This application does not make special limitations on this.

[0151] In some examples, the discharge switch 128 can include any switching device such as a transistor, a field-effect transistor, a thyristor, etc. For example, the discharge switch 128 can include a MOS transistor or a bipolar transistor, etc. The MOS transistor can be an NMOS transistor or a PMOS transistor, for example.

[0152] In some examples, the overvoltage detection module 123 is further configured to:

[0153] When the voltage of the second pin is less than the second voltage threshold, control the discharge switch 128 to turn off. The second voltage threshold is less than the first voltage threshold. Through the above settings, after the voltage on the second pin returns to the normal and reasonable range, the discharge function of the discharge switch 128 can be timely turned off, enabling the first pin to be used normally, that is, enabling the first pin to timely and normally perform its corresponding interface function, improving the user experience.

[0154] Figure 10 It is a schematic diagram of another example of the circuit structure of the electronic device 100 provided by the embodiments of the present application. Figure 10 The shown circuit structure can be regarded as Figure 9 a more specific lower-level implementation manner of the previously shown Figure 10 circuit structure. As shown, in this embodiment, the aforementioned first pin and second pin are the VBUS pin and the D+ / D- pin respectively. In the fast charging scenario, the operating voltage of the VBUS pin is 20V, and the operating voltage of the D+ / D- pin is 3.3V. The aforementioned first functional circuit 131 and second functional circuit 132 respectively include a charging chip and an SOC. The maximum withstand voltage of the charging chip is 24V, and the maximum withstand voltage of the SOC is 5.0V.

[0155] The aforementioned first protection circuit 125 and second protection circuit 126 respectively include a first transient voltage suppressor TVS1 and a second transient voltage suppressor TVS2. One end of the first transient voltage suppressor TVS1 is connected to the first connection path 121, and the other end is grounded. One end of the second transient voltage suppressor TVS2 is connected to the second connection path 122, and the other end is grounded. The VC of the first transient voltage suppressor TVS1 is less than the maximum withstand voltage of the charging chip, for example, it can be 20V or 22V. The VC of the second transient voltage suppressor TVS2 is less than the maximum withstand voltage of the SOC, for example, it can be 4.2V or 4.5V.

[0156] On the above basis, assuming that there is a parasitic coupling path between the VBUS pin and the D+ / D- pins, the protection working principle of the interface circuit 110 in abnormal scenarios is as follows:

[0157] (1) The electronic device 100 is inserted into a high-voltage fast charger, and the charger and the electronic device 100 successfully perform a protocol handshake and start the boost mode, and the voltage on the VBUS pin gradually increases.

[0158] (2) The voltage on the VBUS pin further increases. Because there is parasitic coupling between the VBUS pin and the D+ / D- pins, the voltage on the D+ / D- pins synchronously increases. When the overvoltage detection module 123 detects that the voltage on the D+ / D- pins exceeds 4V (i.e., the first voltage threshold, which is set between 3.3V and 5V), it outputs a discharge control signal to the discharge switch 128 to turn on the discharge function.

[0159] (3) The overvoltage detection module 123 outputs a discharge control signal to control the discharge switch 128 to conduct to open the discharge channel. After the necessary response time of the circuit, the voltage on the VBUS pin starts to decrease.

[0160] (4) The charger (such as a wall plug adapter) detects an abnormal output and turns off the VBUS output.

[0161] (5) The voltage on the VBUS pin rapidly decreases, and at the same time, the voltage coupled to the D+ / D- pins also rapidly decreases. When the overvoltage detection module 123 detects that the voltage is lower than 3.3V (i.e., the second voltage threshold, which is lower than the aforementioned threshold of 4V), it sends a discharge-off control signal to the discharge switch 128 to turn off the discharge function. At this time, the discharge switch 128 is turned off, and the VBUS pin is no longer grounded.

[0162] Figure 11 It is the working timing diagram of the overvoltage detection module 123 for protecting the second connection path 122. As Figure 11As shown in the figure, when there is a parasitic coupling path between the VBUS pin and the D+ / D- pins, the voltage on the D+ / D- pins rises rapidly. When the voltage on the D+ / D- pins reaches the first voltage threshold V1 (i.e., the trigger threshold), after a detection time t1, it is detected by the overvoltage detection module 123. The overvoltage detection module 123 starts to output a discharge control signal (enable signal, high level) to the discharge switch 128. After a discharge enable response time t2, the discharge switch 128 is turned on, and the discharge circuit of the VBUS pin becomes effective (the VBUS pin is grounded). During the subsequent discharge time t3, the voltage on the VBUS pin drops rapidly, and the voltage on the D+ / D- pins also drops rapidly until the voltage on the D+ / D- pins drops to the second voltage threshold V2 (i.e., the release threshold). After a detection time t4, it is detected by the overvoltage detection module 123. The overvoltage detection module 123 starts to output a discharge shutdown control signal (disable signal, low level) to the discharge switch 128. After a discharge shutdown response time t5, the discharge switch 128 is turned off, and the VBUS pin is no longer grounded. At this time, the VBUS pin can continue to perform the charging function.

[0163] For each of the above durations, t1 + t2 and t4 + t5 can generally be achieved within 10 μs by the circuit, and t3 does not exceed 10 μs at most. Considering the worst-case scenario where the VBUS and D+ / D- pins are short-circuited, the maximum coupled energy does not exceed 5 A@20 μs, which is much less than Figure 4 100 A@20 μs in the standard surge current model shown. This shows that the interface circuit 110 provided by the embodiments of the present application can effectively protect the second transient voltage suppressor TVS2 and devices such as SOC in the circuit behind the D+ / D- pins.

[0164] Figure 12 is a schematic diagram of an example of the interface circuit 120 provided by the embodiments of the present application.

[0165] As Figure 12 shown, in the embodiments of the present application, the discharge switch 128 includes a MOS transistor, and the MOS transistor can be, for example, an NMOS transistor. Among them, the gate (gate, G) of the MOS transistor is connected to the output terminal of the overvoltage detection module 123, the source (source, S) of the MOS transistor is grounded, and the drain (drain, D) of the MOS transistor is connected to the first pin. For example, the drain of the MOS transistor is connected to the first connection path 121 and is electrically connected to the first pin through the first connection path 121.

[0166] The MOS transistor has the advantages of low drive power, fast response speed, small size, low cost, simple and easy to use, etc. The discharge switch 128 in the embodiments of the present application selects a MOS transistor, which is beneficial to simplify the circuit structure, reduce the implementation cost of the interface circuit 120, and is beneficial to improve the control efficiency of the overvoltage detection module 123 for the discharge switch 128, ensuring effective protection of the devices at the rear stage of the second pin.

[0167] As Figure 12 shown, the overvoltage detection module 123 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the second pin. For example, the first end of the first resistor R1 is connected to the second connection path 122 and is electrically connected to the second pin through the second connection path 122. The second end of the first resistor R1 is connected in parallel to the first end of the second resistor R2 and the gate of the MOS transistor, and the second end of the second resistor R2 is grounded. The cost of the overvoltage detection module 123 with the above structure is extremely low, so it is beneficial to reduce the implementation cost of the interface circuit 120.

[0168] Specifically, the value selection of the first resistor R1 and the second resistor R2 is strongly related to the type selection of the MOS transistor. Assuming that the turn-on voltage of the MOS transistor is 0.7V and the aforementioned first voltage threshold V1 = 4.2V, then according to the voltage division principle, the resistance value of the first resistor R1 should be five times that of the second resistor R2. For example, the resistance value of the first resistor R1 is 100KΩ (kiloohm), and the resistance value of the second resistor R2 is 20KΩ.

[0169] That is to say, when the voltage of the second pin is greater than 4.2V, the voltage input to the gate of the MOS transistor is greater than 0.7V, that is, greater than the turn-on voltage, which is equivalent to outputting a high level (enable signal) to the MOS transistor. Therefore, the MOS transistor is enabled to connect the source and the drain to each other. At this time, the first pin is grounded through the MOS transistor. When the voltage on the second pin is less than 4.2V, the voltage input to the gate of the MOS transistor is less than 0.7V, that is, less than the turn-on voltage, which is equivalent to outputting a low level (disable signal) to the MOS transistor. Therefore, the MOS transistor is disabled to disconnect the source and the drain from each other. At this time, the first pin is no longer grounded.

[0170] Exemplarily, a diode is further provided on the connection path between the first resistor R1 and the MOS transistor. The diode is configured to be able to output current (voltage) to the MOS transistor and can achieve reverse cut-off of the current to ensure the circuit stability and reliability of the interface circuit 120.

[0171] Figure 13 is a schematic diagram of another example of the interface circuit 120 provided by the embodiments of the present application.

[0172] As Figure 13As shown, in this embodiment, the overvoltage detection module 123 includes a comparator. The first input terminal IN#1 (i.e., the positive terminal of the comparator) of the comparator is connected to the second pin, and the second input terminal IN#2 (i.e., the negative terminal of the comparator) of the comparator is used to receive a voltage reference signal. The output terminal OUT of the comparator is connected to the gate of the MOS transistor.

[0173] In this way, the comparator can control the MOS transistor according to the comparison result between the voltage value of the input signal at the first input terminal IN#1 (such as the voltage value of the second pin) and the voltage value of the voltage reference signal. For example, when the voltage value of the input signal is greater than the voltage value of the voltage reference signal, the output terminal of the comparator outputs a high-level signal to the discharge switch 128 to control the discharge switch 128 to conduct. When the voltage value of the input signal is less than the voltage value of the voltage reference signal, the output terminal of the comparator outputs a low-level signal to the discharge switch 128 to control the discharge switch 128 to turn off.

[0174] For example, the rising-edge trigger threshold V1 of the comparator = ref = 4V, that is, the first voltage threshold is 4V. When the voltage value of the input signal at the first input terminal IN#1 is greater than 4V, the comparator controls the discharge switch 128 to conduct. When the voltage value of the input signal at the first input terminal IN#1 is less than 4V, the comparator controls the discharge switch 128 to turn off.

[0175] Exemplarily, the first input terminal IN#1 of the comparator can be directly connected to the second pin. At this time, the voltage value of the input signal at the first input terminal IN#1 is the voltage value of the second pin. Alternatively, the first input terminal IN#1 of the comparator can also be connected to the second pin through a resistor voltage divider device. At this time, the voltage value of the input signal at the first input terminal IN#1 is the voltage value after voltage reduction. The embodiments of the present application do not make special limitations on this.

[0176] The overvoltage detection module 123 includes a comparator, which is beneficial to conveniently and flexibly set the first voltage threshold. The comparator also has the advantages of strong output driving ability, fast response speed, low cost, and being suitable for integrated chips, which is beneficial to simplifying the circuit structure, reducing the implementation cost of the interface circuit 120, and improving the control efficiency of the overvoltage detection module 123 for the discharge switch 128 to ensure effective protection of the devices after the second pin.

[0177] In some examples, the comparator can be a hysteresis comparator. The hysteresis comparator can suppress the influence on the output result due to the fluctuation of the input signal (such as reducing generated noise or glitches, etc.), that is, it can avoid the jitter problem and improve the stability and reliability of the control of the discharge switch 128 by the overvoltage detection module 123. In addition, selecting a hysteresis comparator for the overvoltage detection module 123 is also beneficial to conveniently and flexibly set the aforementioned second voltage threshold.

[0178] For example, the rising-edge trigger threshold V1 of the hysteresis comparator is V1 = ref = 4V, that is, the set first voltage threshold is 4V, and the falling-edge release threshold V2 = V1 - hysteresis voltage 700mV = 3.3V, that is, the second voltage threshold is 3.3V. That is to say, setting the rising-edge trigger threshold can achieve the setting of the first voltage threshold, and setting the hysteresis voltage can achieve the setting of the second voltage threshold.

[0179] In some examples, the above comparator can also be replaced by other devices such as logic gates. In addition, the GPIO pins of the SOC can be reused, and the voltage of the second pin can be detected by detecting the high and low levels of the GPIO pins, and the SOC can further control the discharge switch 128 according to the detection result. At this time, a voltage-dividing resistor can be connected in series between the second pin and the SOC according to actual requirements.

[0180] Exemplarily, the overvoltage detection module 123 can be a board-level independent module, or can be integrated into the SOC or the internal of the charging chip, or can be integrated into the internal of any third-party chip or IC such as a power management unit (PMU).

[0181] Figure 14 It is a schematic diagram of the overvoltage detection module provided by the embodiment of the present application integrated in the SOC. As Figure 14 shown, the overvoltage detection module 123 can be integrated into the internal of the charging chip. At this time, the overvoltage detection module 123 can be regarded as a part of the charging chip.

[0182] Figure 15 It is a schematic diagram of the overvoltage detection module provided by the embodiment of the present application integrated in the charging chip. As Figure 15 shown, the overvoltage detection module 123 can be integrated into the internal of the SOC. At this time, the overvoltage detection module 123 can be regarded as a part of the SOC.

[0183] Combined with the above electronic device 100, the embodiment of the present application also provides a control method for an interface circuit. This control method can be applied to the electronic device 100 provided in the foregoing embodiment, or applied to a chip or a chip system in the electronic device 100. The following is a method embodiment provided by the present application, and this method embodiment corresponds to the foregoing product (device) embodiment.

[0184] Figure 16It is a flowchart of a control method 400 for an interface circuit provided by an embodiment of the present application. The control method 400 can be applied to the aforementioned electronic device 100. The electronic device 100 includes an external interface 110. The external interface 110 includes a first pin and a second pin. The operating voltage of the first pin is greater than that of the second pin. The interface circuit 120 includes an overvoltage detection module 123 and a voltage reduction module 124. The control method 400 includes:

[0185] Step 410, the overvoltage detection module 123 detects the voltage of the second pin.

[0186] Step 420, when the voltage of the second pin is greater than the first voltage threshold, the overvoltage detection module 123 controls the voltage reduction module 124 to reduce the voltage of the first pin.

[0187] Optionally, in step 420, the overvoltage detection module 123 controls the voltage reduction module 124 to reduce the voltage of the first pin, including:

[0188] The overvoltage detection module 123 controls the voltage reduction module to make the first pin enter an abnormal state, so that the electronic device 100 or the external device 200 connected to the external interface reduces the voltage of the first pin based on a preset circuit protection program.

[0189] Optionally, the control method 400 further includes:

[0190] When the voltage of the second pin is less than the second voltage threshold, the overvoltage detection module 123 controls the voltage reduction module 124 to make the first pin enter a normal state, and the second voltage threshold is less than the first voltage threshold.

[0191] Figure 17 It is a flowchart of a control method 500 for an interface circuit provided by an embodiment of the present application. The control method 500 can be regarded as a more subordinate and specific implementation manner of the control method 400. The control method 500 can be applied to the aforementioned electronic device 100. The electronic device 100 includes an external interface 110. The external interface 110 includes a first pin and a second pin. The operating voltage of the first pin is greater than that of the second pin. The interface circuit 120 includes an overvoltage detection module 123 and a voltage reduction module 124. The voltage reduction module 124 includes a discharge switch 128. The first end of the discharge switch 128 is connected to the first pin, and the second end is grounded. The control method 500 includes:

[0192] Step 510, the overvoltage detection module 123 detects the voltage of the second pin.

[0193] Step 520, when the voltage of the second pin is greater than the first voltage threshold, the overvoltage detection module 123 controls the discharge switch 128 to conduct, so that the first pin is grounded.

[0194] Optionally, the control method 400 further includes:

[0195] Step 530, when the voltage of the second pin is less than the second voltage threshold, the overvoltage detection module 123 controls the discharge switch 128 to turn off, and the second voltage threshold is less than the first voltage threshold.

[0196] Regarding the above Figure 16 、 Figure 17 For the introduction and description of the control method 400 and the control method 500 shown above, refer to the corresponding descriptions in the above text, and details are not repeated here.

[0197] The embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program runs on an electronic device, the electronic device is caused to execute the control method 400 or the control method 500 provided in the foregoing embodiments.

[0198] The embodiment of the present application further provides a computer program product, including: computer program code. When the computer program code runs on an electronic device, the electronic device is caused to execute the control method 400 or the control method 500 provided in the foregoing embodiments.

[0199] The embodiment of the present application further provides an electronic device, including: a memory storing instructions; a processor. When the instructions are run by the processor, the electronic device is caused to execute the control method 400 or the control method 500 provided in the foregoing embodiments. The electronic device may be, for example, the foregoing electronic device 100.

[0200] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present application, and all should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An interface circuit, characterized in that, Applied to an electronic device, the electronic device includes an external interface, the external interface includes a first pin and a second pin, and the operating voltage of the first pin is greater than that of the second pin. The interface circuit includes: A buck module; An overvoltage detection module for detecting the voltage of the second pin and controlling the buck module to reduce the voltage of the first pin when the voltage of the second pin is greater than a first voltage threshold.

2. The interface circuit according to claim 1, wherein When the voltage of the second pin is greater than the first voltage threshold, the overvoltage detection module is specifically configured to: Control the buck module to make the first pin enter an abnormal state, so that the electronic device or an external device connected to the external interface reduces the voltage of the first pin based on a preset circuit protection program.

3. The interface circuit according to claim 1 or 2, characterized in that, The buck module includes: A discharge switch, the first end of the discharge switch is used to connect to the first pin, and the second end is used to ground; When the voltage of the second pin is greater than the first voltage threshold, the overvoltage detection module is specifically configured to: Control the discharge switch to conduct to ground the first pin.

4. The interface circuit according to claim 3, wherein The overvoltage detection module is further configured to: When the voltage of the second pin is less than a second voltage threshold, control the discharge switch to turn off, and the second voltage threshold is less than the first voltage threshold.

5. The interface circuit according to claim 3 or 4, characterized in that, The discharge switch includes a metal oxide semiconductor MOS transistor, the gate of the MOS transistor is connected to the overvoltage detection module, the source of the MOS transistor is used to ground, and the drain of the MOS transistor is used to connect to the first pin.

6. The interface circuit according to claim 5, characterized in that, The overvoltage detection module includes a first resistor and a second resistor. The first end of the first resistor is used to connect to the second pin, and the second end of the first resistor is connected in parallel to the first end of the second resistor and the gate of the MOS transistor, and the second end of the second resistor is used to ground.

7. The interface circuit according to claim 5 or 6, characterized in that The overvoltage detection module includes a comparator. The first input terminal of the comparator is used to connect to the second pin, the second input terminal of the comparator is used to receive a voltage reference signal, and the output terminal of the comparator is connected to the gate of the MOS transistor.

8. The interface circuit according to any one of claims 1-7, characterized in that, The interface circuit further includes: A first connection path, the first end is used to connect to the first pin, and the second end is used to connect to the first functional circuit of the electronic device; A second connection path, the first end is used to connect to the second pin, and the second end is used to connect to the second functional circuit of the electronic device; A second protection circuit connected to the second connection path for absorbing the surge energy entering the second connection path to protect the second functional circuit.

9. The interface circuit according to claim 8, wherein The first voltage threshold is less than the maximum withstand voltage of the second functional circuit.

10. The interface circuit according to claim 8 or 9, characterized in that, The second protection circuit includes a second transient voltage suppressor TVS. The first end of the second TVS is connected to the second connection path, and the second end of the second TVS is used to ground.

11. The interface circuit according to any one of claims 1-10, characterized in that, The external interface is a Type-C interface, the first pin is a VBUS pin, and the second pin is any one of a D+ pin, a D- pin, a CC1 pin, a CC2 pin, an SBU1 pin, and an SBU2 pin.

12. The interface circuit according to any one of claims 1-11, characterized in that, The overvoltage detection module is integrated inside a charging chip or a system-on-chip SOC.

13. An electronic device, characterized in that, Including: An external interface, the external interface includes a first pin and a second pin, and the operating voltage of the first pin is greater than the operating voltage of the second pin; And, The interface circuit according to any one of claims 1-12.

14. A control method for an interface circuit, characterized in that Applied to an electronic device, the electronic device includes an external interface, the external interface includes a first pin and a second pin, the operating voltage of the first pin is greater than the operating voltage of the second pin, the interface circuit includes a buck module and an overvoltage detection module, and the control method includes: The overvoltage detection module detects the voltage of the second pin; When the voltage of the second pin is greater than a first voltage threshold, the overvoltage detection module controls the buck module to reduce the voltage of the first pin.

15. The control method according to claim 14, wherein The overvoltage detection module controls the buck module to reduce the voltage of the first pin, including: The overvoltage detection module controls the buck module to make the first pin enter an abnormal state, so that the electronic device or an external device connected to the external interface reduces the voltage of the first pin based on a preset circuit protection program.

16. The control method according to claim 14 or 15, characterized in that, The buck module includes a discharge switch, a first end of the discharge switch is connected to the first pin, a second end is grounded, and the overvoltage detection module controls the buck module to reduce the voltage of the first pin, including: The overvoltage detection module controls the discharge switch to conduct to ground the first pin.

17. The control method according to claim 16, wherein The control method further includes: When the voltage of the second pin is less than a second voltage threshold, the overvoltage detection module controls the discharge switch to turn off, and the second voltage threshold is less than the first voltage threshold.

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