Protection circuit and electronic device

Abstract

The present application relates to the technical field of electronic information, and relates to a protection circuit and an electronic device, which are used to solve the problem of EOS causing damage to external ports. The protection circuit is applied to the electronic device having an external port and a processing chip. The protection circuit comprises a first protection unit and a second protection unit. A first terminal of the first protection unit is configured to be coupled to a pin of the external port, and a second terminal of the first protection unit is configured to be coupled to the processing chip. The first protection unit is configured to isolate direct-current stress and / or surge stress at the first terminal of the first protection unit from the second terminal of the first protection unit. A first terminal of the second protection unit is coupled to the first terminal of the first protection unit, and a second terminal of the second protection unit is coupled to a ground terminal. The second protection unit is configured to reduce the surge stress and / or electrostatic stress at the first terminal of the first protection unit.

Description

Protecting circuits and electronic equipment

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on October 13, 2023, with application number 202311342351.6 and invention name “Protective Circuit and Electronic Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of electronic information technology, and in particular to a protection circuit and electronic equipment. Background Art

[0003] With the rapid development of electronic information technology, electronic devices can use their own external ports to connect to some external devices, so as to realize functions that the electronic devices themselves cannot realize through the external devices; alternatively, electronic devices can also use their own external ports to connect to chargers to charge the internal batteries of the electronic devices.

[0004] Typically, electronic devices have exposed external ports. This makes them susceptible to electrical overstress (EOS) from the environment, which can damage them and render them partially inoperable. Therefore, there is an urgent need for designs that can protect external ports from EOS.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a protection circuit and an electronic device for solving the problem of damage to an external port caused by EOS.

[0007] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0008] In a first aspect, a protection circuit is provided. The protection circuit is applied to an electronic device having an external port and a processing chip. The protection circuit includes a first protection unit and a second protection unit. The first end of the first protection unit is used to couple a pin of the external port, and the second end of the first protection unit is used to couple the processing chip. The first protection unit is configured to isolate the DC stress and / or surge stress at the first end of the first protection unit from the second end of the first protection unit. The first end of the second protection unit is coupled to the first end of the first protection unit, and the second end of the second protection unit is coupled to the ground end. The second protection unit is configured to reduce the surge stress and / or electrostatic stress at the first end of the first protection unit.

[0009] The following explanation will be given using an example in which the electronic device is a mobile phone, the external port includes the Type-C port of the mobile phone, and the processing chip is a system on chip (SOC), but this should not be used as a limitation on the electronic device, external port, and processing chip.

[0010] The protection circuit may include a first protection unit and a second protection unit. The first protection unit may be coupled to a pin of the Type-C port, and the first protection unit may be coupled to the SOC in the mobile phone. It is understood that the first end of the first protection unit serves as the input end of the protection circuit, and the second end of the first protection unit serves as the output end of the protection circuit.

[0011] The first end of the second protection unit is coupled to the first end of the first protection unit, and the second end of the second protection unit is coupled to the ground end. It can be understood that the second protection unit is connected in series between the first end of the first protection unit and the ground end.

[0012] Because the Type-C port of a mobile phone is exposed, it is easy for the Type-C port to introduce EOS from the environment, thereby causing damage to the Type-C port and causing at least some of the Type-C port to lose its functionality. For example, if the Type-C port is used as a charging port with a fast charging function, if the Type-C port is damaged by EOS, the Type-C port will lose its fast charging function as a charging port. For another example, if the Type-C port is used as a data transmission port, if the Type-C port is damaged by EOS, the Type-C port will lose its data transmission function as a data transmission port.

[0013] EOS mainly includes electrostatic stress, surge stress and DC stress. Among them, the electrostatic stress of the Type-C port is mainly due to the stress caused by factors such as friction electrification in the environment. The voltage value corresponding to electrostatic stress is very large and can reach thousands of volts. The surge stress of the Type-C port is the stress caused by the plugging and unplugging of the Type-C plug at the Type-C port. The voltage value corresponding to the surge stress can be more than ten volts to several dozen volts. DC stress is mainly caused by the external conductor (such as liquid seeping into the Type-C port) forming a path between different pins in the Type-C port, resulting in a large DC voltage on the pins and causing stress. The voltage value corresponding to DC stress can be more than ten volts to several dozen volts.

[0014] Among them, electrostatic stress occurs for a shorter time, which is nanosecond level stress; surge stress occurs for a slightly longer time, which is microsecond level stress; and DC stress occurs for the longest time, which is millisecond to second level stress.

[0015] In the embodiments of the present application, when at least one of the above-mentioned electrostatic stress, surge stress and DC stress occurs on the pins of the Type-C port, EOS can avoid damage to the SOC by EOS after being protected by the second protection unit and the first protection unit in sequence.

[0016] The second protection unit is coupled to the first end of the first protection unit. It can be understood that the signal from the pin of the Type-C port is first protected by the second protection unit, then by the first protection unit, and finally flows from the second end of the first protection unit to the mobile phone chip, thus completing a single signal transmission from the pin of the Type-C port to the SOC.

[0017] The type of stress protection provided by the first protection unit may be different from the type of stress protection provided by the second protection unit.

[0018] The first protection unit can be configured to isolate the SOC from DC stress and / or surge stress on the pins of the Type-C port. Exemplarily, the first protection unit isolates the SOC from DC stress on the pins of the Type-C port. In another exemplary embodiment, the first protection unit isolates the SOC from surge stress on the pins of the Type-C port. In another exemplary embodiment, the first protection unit isolates the SOC from DC stress and surge stress on the pins of the Type-C port.

[0019] The second protection unit may be configured to reduce electrostatic stress and / or surge stress at the first end of the first protection unit. Exemplarily, the second protection unit may reduce electrostatic stress at the first end of the first protection unit. Exemplarily, the second protection unit may reduce surge stress at the first end of the first protection unit. Exemplarily, the second protection unit may reduce electrostatic stress and surge stress at the first end of the first protection unit.

[0020] It can be understood that after EOS occurs on the pin of the Type-C port, the second protection unit will first protect the electrostatic stress and / or surge stress of the first end of the first protection unit, and then the first protection unit will protect the DC stress and / or surge stress in the EOS, so that after being protected by the first protection unit and the second protection unit, the EOS that occurs on the pin of the Type-C port will not cause damage to the SOC.

[0021] In some feasible implementations of the first aspect, the first protection unit includes a switch subcircuit. A first end of the switch subcircuit is coupled to a pin of an external port, and a second end of the switch subcircuit is coupled to a processing chip. Isolating DC stress and / or surge stress at the first end of the first protection unit from the second end of the first protection unit includes isolating the first end of the switch subcircuit from the second end of the switch subcircuit.

[0022] In some examples, the switch sub-circuit can detect whether DC stress and / or surge stress are present on the pins of the Type-C port. For example, DC stress and / or surge stress correspond to a relatively large voltage value, so the switch sub-circuit can determine whether DC stress and / or surge stress are present on the pins of the Type-C port by detecting the voltage at the first terminal of the switch sub-circuit.

[0023] When the switch subcircuit detects that the voltage at the first end of the switch subcircuit is greater than or equal to a preset threshold, it determines that there is DC stress and / or surge stress at the voltage at the first end of the switch subcircuit, and disconnects the first end of the switch subcircuit from the second end of the switch subcircuit, thereby disconnecting the connection between the pin of the Type-C port and the SOC, isolating the DC stress and / or surge stress from the SOC, thereby achieving protection against EOS and preventing EOS from damaging the SOC.

[0024] When the switch subcircuit detects that the voltage at the first end of the switch subcircuit is less than a preset threshold, it determines that there is no DC stress and / or surge stress on the voltage at the first end of the switch subcircuit, maintains conduction between the first end of the switch subcircuit and the second end of the switch subcircuit, thereby conducting the connection between the pin of the Type-C port and the SOC, and completing the signal transmission from the pin of the Type-C port to the SOC.

[0025] In other examples, the switch sub-circuit can receive control from other units to disconnect the connection between the pins of the Type-C port and the SOC when there is DC stress and / or surge stress on the pins of the Type-C port, and to connect the connection between the pins of the Type-C port and the SOC when there is no DC stress and / or surge stress on the pins of the Type-C port.

[0026] Exemplarily, the protection circuit 200 may further include a control unit. The control unit is coupled to the control terminal of the switch subcircuit. The control unit is configured to provide a control voltage to the control terminal of the switch subcircuit.

[0027] For example, the control unit can detect whether there is DC stress and / or surge stress on the pins of the Type-C port. When there is no DC stress and / or surge stress on the pins of the Type-C port, the control unit can output a first control voltage; when there is DC stress and / or surge stress on the pins of the Type-C port, the control unit can output a second control voltage.

[0028] When the control end of the switch sub-circuit receives the first control voltage, the conduction between the first end of the switch sub-circuit and the second end of the switch sub-circuit is maintained, thereby conducting the connection between the pin of the Type-C port and the SOC, completing the signal transmission from the pin of the Type-C port to the SOC.

[0029] When the control end of the switch sub-circuit receives the second control voltage, the connection between the first end of the switch sub-circuit and the second end of the switch sub-circuit is disconnected, thereby disconnecting the connection between the pin of the Type-C port and the SOC, isolating the DC stress and / or surge stress from the SOC, achieving protection against EOS and preventing EOS from damaging the SOC.

[0030] In some feasible implementations of the first aspect, the protection circuit further includes a control unit. The switch subcircuit includes a transistor. A first terminal of the transistor is coupled to a pin of an external port, a second terminal of the transistor is coupled to a processing chip, and a control terminal of the transistor is coupled to the control unit. Isolating the first terminal of the switch subcircuit from the second terminal of the switch subcircuit includes isolating the first terminal of the transistor from the second terminal of the transistor.

[0031] The transistor T may be a P-type channel transistor or an N-type channel transistor. An N-type channel transistor is used as an example for description.

[0032] In some examples, when there is no DC stress and / or surge stress on the pins of the Type-C port, the control unit can output a high voltage signal (a first control voltage), and the control end of the switch subcircuit receives the high voltage signal, maintaining conduction between the first end of the switch subcircuit and the second end of the switch subcircuit, thereby conducting the connection between the pins of the Type-C port and the SOC, and completing the signal transmission from the pins of the Type-C port to the SOC. When there is DC stress and / or surge stress on the pins of the Type-C port, the control unit can output a low voltage signal (a second control voltage), and the control end of the switch subcircuit receives the low voltage signal, disconnecting the first end of the switch subcircuit and the second end of the switch subcircuit, thereby disconnecting the pins of the Type-C port and the SOC, isolating the DC stress and / or surge stress from the SOC, and achieving protection against EOS, thereby preventing EOS from causing damage to the SOC.

[0033] In other examples, the control unit can provide a constant control voltage to the control terminal of the switch subcircuit. For example, the control voltage can be 5V, 6V, 8V, 10V, etc., which is not limited in this application. Transistor T switches on or off the connection between the pin of the Type-C port and the SOC based on the voltage difference between the voltage of the control terminal of transistor T and the voltage of the second terminal of transistor T.

[0034] When there is no DC stress and / or surge stress on the pin of the Type-C port, the voltage difference between the voltage of the control electrode of transistor T and the voltage value of the second electrode of transistor T is greater than zero, and transistor T turns on the connection between the first electrode of transistor T and the second electrode of transistor T, thereby turning on the connection between the pin of the Type-C port and the SOC, completing the signal transmission from the pin of the Type-C port to the SOC.

[0035] When DC stress and / or surge stress exists on the pin of the Type-C port, the voltage of the DC stress and / or surge stress is transmitted to the second electrode of the transistor T, so that the voltage of the second electrode of the transistor T is pulled up, and the voltage difference between the voltage of the control electrode of the transistor T and the voltage value of the second electrode of the transistor T is less than zero. The transistor T isolates the connection between the first electrode of the transistor T and the second electrode of the transistor T, thereby disconnecting the connection between the pin of the Type-C port and the SOC, isolating the DC stress and / or surge stress from the SOC, achieving protection against EOS, and preventing EOS from causing damage to the SOC.

[0036] In some feasible implementations of the first aspect, the first protection unit includes a capacitor. A first plate of the capacitor is coupled to a pin of the external port, and a second plate of the capacitor is coupled to the processing chip. Isolating DC stress and / or surge stress at a first end of the first protection unit from the second end of the first protection unit includes: isolating the DC stress of the first plate of the capacitor from the second plate of the capacitor.

[0037] The capacitor allows AC signals to pass through and blocks DC stress. That is, the AC signal on the pins of the external port can pass through the capacitor to the processing chip, while the DC stress on the pins of the external port is blocked by the capacitor and cannot be transmitted to the processing chip.

[0038] In some feasible implementations of the first aspect, the first protection unit includes a switch. A first contact of the switch is used to couple to a pin of an external port, a second contact of the switch is used to couple to a processing chip, and the first contact and the second contact are connected or disconnected. Isolating a DC stress and / or a surge stress at a first end of the first protection unit from a second end of the first protection unit includes: when a voltage at the first contact is greater than or equal to a preset threshold, disconnecting the first contact from the second contact, thereby isolating the DC stress and / or surge stress at the first contact from the second contact.

[0039] Disconnecting the first and second contacts is equivalent to disconnecting the Type-C port pins from the SoC, isolating the SoC from DC stress and / or surge stress, protecting against EOS and preventing damage to the SoC.

[0040] In some feasible implementations of the first aspect, the second protection unit includes a first overvoltage protection subcircuit. A first end of the first overvoltage protection subcircuit is coupled to a first end of the first protection unit, and a second end of the first overvoltage protection subcircuit is coupled to a ground end. Reducing surge stress and / or electrostatic stress at the first end of the first protection unit includes: when a voltage at the first end of the first overvoltage protection subcircuit is greater than or equal to a preset first startup voltage, conducting the first end of the first overvoltage protection subcircuit with the second end of the first overvoltage protection subcircuit to reduce the voltage at the first end of the first protection unit.

[0041] The first overvoltage protection subcircuit includes a protection state and a non-protection state. When the first overvoltage protection subcircuit is in the protection state, the first end of the first overvoltage protection subcircuit and the second end of the first overvoltage protection subcircuit are electrically connected, thereby connecting the first end of the first protection unit to the ground terminal, thereby pulling down the voltage at the first end of the first protection unit. When the first overvoltage protection subcircuit is in the non-protection state, the first end of the first overvoltage protection subcircuit and the second end of the first overvoltage protection subcircuit are disconnected, thereby disconnecting the first end of the first protection unit from the ground terminal, thereby smoothly transmitting the signal from the pin of the Type-C port to the first protection unit.

[0042] Whether the first overvoltage protection subcircuit is in a protective state or a non-protective state may depend on the voltage at the first terminal of the first overvoltage protection subcircuit. For example, when the voltage at the first terminal of the first overvoltage protection subcircuit is greater than or equal to a preset first startup voltage, the first overvoltage protection subcircuit may be in a protective state; and when the voltage at the first terminal of the first overvoltage protection subcircuit is less than the first startup voltage, the first overvoltage protection subcircuit may be in a non-protective state.

[0043] In some feasible implementations of the first aspect, the first overvoltage protection subcircuit includes a first transient voltage suppressor. A first terminal of the first transient voltage suppressor is coupled to a first end of the first protection unit, and a second terminal of the first transient voltage suppressor is coupled to ground. Electrically connecting the first end of the first overvoltage protection subcircuit to the second end of the first overvoltage protection subcircuit includes: electrically connecting the first terminal of the first transient voltage suppressor to the second terminal of the first transient voltage suppressor.

[0044] The first transient voltage suppressor tube can be a unidirectional transient voltage suppressor tube or a bidirectional transient voltage suppressor tube, which is not limited in this application.

[0045] When the voltage of the first electrode of the first transient voltage suppressor is greater than or equal to the preset first starting voltage, the first electrode of the first transient voltage suppressor is conductively connected to the second electrode of the first transient voltage suppressor, so that the first end of the first protection unit is conductively connected to the ground end, thereby pulling down the voltage at the first end of the first protection unit.

[0046] When the voltage of the first electrode of the first transient voltage suppressor is lower than the preset first startup voltage, the first electrode of the first transient voltage suppressor is isolated from the second electrode of the first transient voltage suppressor, so that the first end of the first protection unit is isolated from the ground end, so that the signal of the pin of the Type-C port is smoothly transmitted to the first protection unit.

[0047] It is understood that the first startup voltage can be understood as the turn-on voltage of the first transient voltage suppressor. Furthermore, the first transient voltage suppressor also includes a clamping voltage (also known as a limiting voltage), which refers to the maximum voltage allowed to be transmitted from the first terminal of the first transient voltage suppressor to the first end of the first protection unit after conduction between the first terminal of the first transient voltage suppressor and the second terminal of the first transient voltage suppressor. The clamping voltage of the first transient voltage suppressor is lower than the turn-on voltage of the first transient voltage suppressor.

[0048] In some feasible implementations of the first aspect, the first overvoltage protection subcircuit includes a transient voltage suppressor (TVS) tube assembly. A first end of the TVS tube assembly is coupled to a first end of the first protection unit, and a second end of the TVS tube assembly is coupled to ground. The TVS tube assembly includes a plurality of second TVS tubes connected in series.

[0049] The first end of the transient voltage suppression tube assembly is coupled to the first end of the first protection unit, and the second end of the transient voltage suppression tube assembly is coupled to the ground. It can be understood that the first end of the transient voltage suppression tube assembly corresponds to the first end of the first overvoltage protection subcircuit, and the second end of the transient voltage suppression tube assembly corresponds to the second end of the first overvoltage protection subcircuit.

[0050] The transient voltage suppressor assembly may include a plurality of second transient voltage suppressor tubes connected in series. A first electrode of a first second transient voltage suppressor tube among the plurality of second transient voltage suppressor tubes is coupled to the first end of the first protection unit, a first electrode of a second second transient voltage suppressor tube is coupled to the second electrode of the first second transient voltage suppressor tube, and so on, until the second electrode of a last second transient voltage suppressor tube is coupled to the ground terminal.

[0051] Multiple second transient voltage suppressor diodes are connected in series, so the same current flows through each second transient voltage suppressor diode. By connecting multiple second transient voltage suppressor diodes in series, the sum of their turn-on voltages can be used as the turn-on voltage of the entire transient voltage suppressor assembly. Consequently, if the voltage of a single transient voltage suppressor diode is lower than the first turn-on voltage, the turn-on voltage of the transient voltage suppressor assembly can be equalized to the first turn-on voltage by connecting multiple transient voltage suppressor diodes in series, achieving overvoltage protection.

[0052] For example, the transient voltage suppressor tube assembly may include two second transient voltage suppressor tubes. Of course, in some other examples, the transient voltage suppressor tube assembly may also include more second transient voltage suppressor tubes.

[0053] In some feasible implementations of the first aspect, the protection circuit further includes a third protection unit. A first end of the third protection unit is coupled to a second end of the first protection unit, and a second end of the third protection unit is coupled to a ground terminal. The third protection unit is configured to reduce surge stress and / or electrostatic stress at the second end of the first protection unit.

[0054] In some embodiments, in order to prevent DC stress from damaging the second protection unit, the startup voltage of the second protection unit is increased, which will cause the clamping voltage of the second protection unit to also increase, resulting in the clamping voltage of the second protection unit being higher than the safety voltage of the SOC.

[0055] Therefore, the third protection unit can further protect the surge stress and / or electrostatic stress protected by the second protection unit to ensure that the surge stress and / or electrostatic stress protected by the third protection unit is less than or equal to the safety voltage of the SOC, thereby improving the protection performance of the protection circuit to the SOC.

[0056] In other embodiments, even if the clamping voltage of the second protection unit is less than or equal to the safety voltage of the SOC, the third protection unit can further improve the performance of the protection circuit in protecting against surge stress and / or electrostatic stress.

[0057] When there is no surge stress and / or electrostatic stress on the pin of the Type-C port, or when there is surge stress and / or electrostatic stress on the pin of the Type-C port and the second protection unit reduces the voltage of the surge stress and / or electrostatic stress to less than the preset second starting voltage, the voltage at the first end of the third protection unit is less than the preset second starting voltage, the first end of the third protection unit and the second end of the third protection unit are disconnected, so that the second end of the first protection unit is disconnected from the ground end, so that the signal output from the second end of the first protection unit is smoothly transmitted to the SOC and provided to the SOC.

[0058] When surge stress and / or electrostatic stress exists on the pin of the Type-C port and the voltage of the surge stress and / or electrostatic stress is still greater than or equal to the second startup voltage after the second protection unit reduces it, when the voltage at the first end of the third protection unit is greater than or equal to the second startup voltage, conduction occurs between the first end of the third protection unit and the second end of the third protection unit, so that conduction occurs between the second end of the first protection unit and the ground end, thereby pulling down the voltage at the second end of the first protection unit, ensuring that the surge stress and / or electrostatic stress protected by the third protection unit is less than or equal to the safety voltage of the SOC, thereby improving the protection performance of the protection circuit for the SOC.

[0059] In some feasible implementations of the first aspect, the third protection unit includes a second overvoltage protection subcircuit. A first end of the second overvoltage protection subcircuit is coupled to a second end of the first protection unit, and the second end of the second overvoltage protection subcircuit is coupled to a ground end. Reducing surge stress and / or electrostatic stress at the second end of the first protection unit includes: when a voltage at the first end of the second overvoltage protection subcircuit is greater than or equal to a preset second startup voltage, conducting the first end of the second overvoltage protection subcircuit with the second end of the second overvoltage protection subcircuit to reduce the voltage at the second end of the first protection unit.

[0060] The third protection unit may include a second overvoltage protection subcircuit, wherein a first terminal of the second overvoltage protection subcircuit is coupled to a second terminal of the first protection unit, and a second terminal of the second overvoltage protection subcircuit is coupled to a ground terminal.

[0061] The second overvoltage protection subcircuit includes a protection state and a non-protection state. When the second overvoltage protection subcircuit is in the protection state, the first end of the second overvoltage protection subcircuit and the second end of the second overvoltage protection subcircuit are conductively connected, thereby causing conductivity between the second end of the first protection unit and the ground terminal, thereby pulling down the voltage at the second end of the first protection unit. When the second overvoltage protection subcircuit is in the non-protection state, the first end of the second overvoltage protection subcircuit and the second end of the second overvoltage protection subcircuit are disconnected, thereby disconnecting the second end of the first protection unit from the ground terminal GND, thereby smoothly transmitting the signal output from the second end of the first protection unit to the SOC, thereby achieving signal transmission between the pins of the Type-C port and the SOC.

[0062] Whether the second overvoltage protection subcircuit is in a protective state or a non-protective state may depend on the voltage at the first terminal of the second overvoltage protection subcircuit. For example, if the voltage at the first terminal of the second overvoltage protection subcircuit is greater than or equal to a preset second startup voltage, the second overvoltage protection subcircuit may be in a protective state; if the voltage at the first terminal of the second overvoltage protection subcircuit is less than the second startup voltage, the second overvoltage protection subcircuit may be in a non-protective state.

[0063] In some feasible implementations of the first aspect, the protection circuit further includes a first overvoltage protection subcircuit. A second startup voltage corresponding to the second overvoltage protection subcircuit is lower than a first startup voltage corresponding to the first overvoltage protection subcircuit.

[0064] The second startup voltage corresponding to the third protection unit is less than the first startup voltage corresponding to the second protection unit. Exemplarily, the second startup voltage corresponding to the third protection unit is less than the clamping voltage corresponding to the second protection unit. Furthermore, the output voltage corresponding to the second terminal of the third protection unit may be less than or equal to the safety voltage of the SOC.

[0065] In some feasible implementations of the first aspect, the second overvoltage protection subcircuit includes a third transient voltage suppressor. A first terminal of the third transient voltage suppressor is coupled to the second end of the first protection unit, and a second terminal of the third transient voltage suppressor is coupled to ground. Electrically connecting the first end of the second overvoltage protection subcircuit to the second end of the second overvoltage protection subcircuit includes: electrically connecting the first terminal of the third transient voltage suppressor to the second terminal of the third transient voltage suppressor.

[0066] The third transient voltage suppressor tube can be a unidirectional transient voltage suppressor tube or a bidirectional transient voltage suppressor tube, which is not limited in the embodiments of the present application.

[0067] When the voltage at the first terminal of the third transient voltage suppressor is greater than or equal to the second starting voltage, the first terminal of the third transient voltage suppressor is electrically connected to the second terminal of the third transient voltage suppressor, thereby electrically connecting the second terminal of the first protection unit to the ground terminal, thereby pulling down the voltage at the second terminal of the first protection unit. When the voltage at the first terminal of the third transient voltage suppressor is less than the second starting voltage, the first terminal of the third transient voltage suppressor is electrically disconnected from the second terminal of the third transient voltage suppressor, thereby disconnecting the second terminal of the first protection unit from the ground terminal. This allows the signal output from the second terminal of the first protection unit to be smoothly transmitted to the SOC, thereby enabling signal transmission between the pins of the Type-C port and the SOC.

[0068] It can be understood that the second startup voltage can be understood as the turn-on voltage of the third transient voltage suppressor. In addition, the third transient voltage suppressor also includes a clamping voltage (also known as a limiting voltage), which refers to the maximum voltage that the first electrode of the third transient voltage suppressor is allowed to continue transmitting to the SOC after conduction between the first electrode of the third transient voltage suppressor and the second electrode of the third transient voltage suppressor. The clamping voltage of the third transient voltage suppressor is lower than the turn-on voltage of the third transient voltage suppressor.

[0069] In some other examples, the second overvoltage protection subcircuit may also include multiple transient voltage suppressors. In this case, the connection relationship and operating principle of the multiple transient voltage suppressors can refer to the connection relationship and operating principle of the multiple second transient voltage suppressors in the transient voltage suppressor assembly, and will not be repeated here.

[0070] In a second aspect, an electronic device is provided. The electronic device includes: an external port, a processing chip, and a protection circuit coupled to the external port and the processing chip, respectively. The protection circuit is any protection circuit as described in the first aspect.

[0071] The technical effects of the second aspect can be referred to the technical effects of the first aspect, and will not be repeated here.

[0072] In some feasible implementations of the second aspect, the external port includes a plurality of pins, one of which is coupled to the protection circuit and coupled to the processing chip through the protection circuit.

[0073] In some feasible implementations of the second aspect, the external port includes a plurality of pins, wherein the plurality of pins are respectively coupled to different protection circuits, and each pin is coupled to the processing chip via the connected protection circuit.

[0074] For example, multiple pins in the Type-C port (e.g., the D+ pin, the D- pin, and the CC pin) are each connected to a protection circuit and are further coupled to the processing chip through the connected protection circuits. For another example, each pin in the Type-C port can be connected to a protection circuit and coupled to the processing chip for communication through the connected protection circuits.

[0075] In some feasible implementations of the second aspect, the external port may include at least one of a universal serial bus (USB) port, a high definition multimedia interface (HDMI), and a network card interface.

[0076] The USB port may be, for example, a Type-C port, a micro USB port, etc. The network card interface may be, for example, an RJ45 (registered jack45), etc.

[0077] In some feasible implementations of the second aspect, the processing chip includes a SOC or a micro control unit (MCU).

[0078] In some feasible implementations of the second aspect, the electronic device includes at least one circuit board. The first protection unit and the second protection unit in the protection circuit are located on the same circuit board; or the first protection unit and the second protection unit in the protection circuit are located on different circuit boards.

[0079] In some examples, the aforementioned protection circuitry is all located on a single circuit board. Furthermore, the pins on the Type-C port and the SoC may also be located on the same circuit board. It is understood that the pins on the Type-C port, the SoC, and the protection circuitry connecting the pins and the SoC are all located on the same circuit board.

[0080] In other examples, a mobile phone may include two circuit boards. The mobile phone may include a first circuit board and a second circuit board. The area of ​​the first circuit board may be smaller than the area of ​​the second circuit board, or may be equal to or larger than the area of ​​the second circuit board, and this application does not limit this.

[0081] For example, the pins on the Type-C port may be located on a first circuit board, and the above-mentioned protection circuits are all located on a second circuit board.

[0082] For another example, the second protection unit can be located on the first circuit board, and the first protection unit can be located on the second circuit board. In addition, the pins on the Type-C port can be located on circuit board 1 together with the second protection unit, and the SOC can be located on the second circuit board together with the first protection unit.

[0083] The mobile phone may further include a flexible printed circuit (FPC). The FPC may connect two circuit boards, for example, the FPC may connect a first circuit board and a second circuit board respectively.

[0084] The FPC can include multiple signal lines, each of which can be coupled to a signal interface on two adjacent circuit boards, allowing signals to be transmitted outside the two circuit boards, achieving cross-circuit signal transmission. Furthermore, due to the FPC's flexibility, it does not restrict the layout of the two connected circuit boards, facilitating space design within the phone.

[0085] In some feasible implementations of the second aspect, the external port includes a Type-C port, and the Type-C port includes a D+ pin and a D- pin. The electronic device also includes a common-mode inductor, and the common-mode inductor includes a magnetic ring, and a first inductor coil and a second inductor coil respectively wound around the magnetic ring. The first end of the first inductor coil is coupled to the D- pin, and the first end of the second inductor coil is coupled to the D+ pin. The electronic device also includes two protection circuits. In one protection circuit, the first end of the first protection unit is coupled to the second end of the first inductor coil, and the second end of the first protection unit is coupled to the processing chip. In another protection circuit, the first end of the first protection unit is coupled to the second end of the second inductor coil, and the second end of the first protection unit is coupled to the processing chip.

[0086] The first inductor, the second inductor, and the magnetic ring together form a common-mode inductor. This inductor filters common-mode electromagnetic interference signals. As you can see, the first inductor filters electromagnetic interference signals from the Type-C port's D- pin; similarly, the second inductor filters electromagnetic interference signals from the Type-C port's D+ pin. This improves the reliability of signal transmission on the Type-C port.

[0087] At the same time, the D+ pin and D- pin are equipped with protection circuits in the connection circuits with the SOC respectively, which can also protect the D+ pin and D- pin in the Type-C port against EOS, thereby avoiding EOS damage to the SOC and common-mode inductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] FIG1 is a schematic structural diagram of a mobile phone provided in some embodiments;

[0089] FIG2 is a schematic structural diagram of the bottom frame of the mobile phone shown in FIG1 ;

[0090] FIG3 is a schematic diagram of the structure of the Type-C port in FIG2 ;

[0091] FIG4 is a schematic structural diagram of a protection circuit in a mobile phone provided in an embodiment of the present application;

[0092] FIG5 is another structural schematic diagram of the protection circuit shown in FIG4 ;

[0093] FIG6 is another structural diagram of the protection circuit shown in FIG4 ;

[0094] FIG7 is a schematic diagram of another structure of the protection circuit shown in FIG4;

[0095] FIG8 is a schematic structural diagram of another protection circuit in a mobile phone provided in an embodiment of the present application;

[0096] FIG9 is another structural schematic diagram of the protection circuit shown in FIG7 ;

[0097] FIG10 is another structural diagram of the protection circuit shown in FIG8 ;

[0098] FIG11 is a schematic diagram of the structure of the protection circuit shown in FIG10 applied to the D+ pin and D- pin of the Type-C port;

[0099] FIG12 is a schematic diagram showing a structure in which there is no protection circuit between the pins of the Type-C port and the SOC in a mobile phone;

[0100] FIG13 is a schematic diagram of a structure in which a second protection unit is included but a first protection unit is not included between the pin of the Type-C port and the SOC in a mobile phone;

[0101] FIG14 is a schematic structural diagram of the second protection unit in FIG13 applied to the D+ pin of the Type-C port;

[0102] FIG15 is a schematic diagram of a structure in which a first protection unit is included but a second protection unit is not included between the pin of the Type-C port and the SOC in a mobile phone;

[0103] FIG16 is a schematic diagram of a layout of a circuit board and a protection circuit in a mobile phone provided by an embodiment of the present application;

[0104] FIG17 is another schematic diagram of the layout of the circuit board and the protection circuit in the mobile phone provided in an embodiment of the present application. DETAILED DESCRIPTION

[0105] The following will describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0106] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more.

[0107] In addition, in this application, directional terms such as "up", "down", "left", and "right" may be defined including but not limited to the orientation relative to the schematic placement of the components in the drawings. It should be understood that these directional terms may be relative concepts. They are used for relative descriptions and clarifications, and they may change accordingly according to changes in the orientation of the components in the drawings.

[0108] When describing some embodiments, the terms "connected," "connected," and their derivatives may be used. For example, when describing some embodiments, the term "connected" may be used to indicate that two or more components are in direct or indirect physical contact with each other. For example, "A and B are connected" may mean that A and B are connected directly, or that A and B are connected through other components. In addition, the term "coupled" may refer to a method of electrical connection for signal transmission, and coupling may refer to direct coupling or indirect coupling.

[0109] “At least one of A, B and C” has the same meaning as “at least one of A, B or C” and both include the following combinations of A, B and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B and C.

[0110] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0111] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of deviation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0112] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0113] The embodiments of the present application provide a protection circuit and electronic device. The electronic devices provided in the embodiments of the present application may include but are not limited to mobile phones, tablet computers, laptop computers, handheld computers, netbooks, personal digital assistants (PDAs), wearable electronic devices, virtual reality devices, electric vehicles, and other processing devices with their own data processing functions. The electronic devices may also include but are not limited to data cable adapters, docking stations (also known as port replicators), chargers, headphones, speakers, mice, monitors, keyboards, and other external devices that can be connected to the external ports of the processing devices.

[0114] The electronic devices provided in the embodiments of the present application may include an external port. The external port may be a universal serial bus (USB) port, such as a Type-C port or a micro USB port; the external port may also be a high-definition multimedia interface (HDMI) or a network card interface (such as a registered jack 45, or RJ45), etc., and the embodiments of the present application are not limited thereto.

[0115] For ease of understanding, the following description uses a mobile phone as an example of an electronic device with a Type-C port. However, this should not be used as a limitation on electronic devices and external ports.

[0116] Figure 1 shows a schematic structural diagram of a mobile phone; Figure 2 shows a schematic structural diagram of the bottom frame of the mobile phone shown in Figure 1; Figure 3 shows a schematic structural diagram of the Type-C port in Figure 2.

[0117] As shown in Figure 1, the mobile phone 100 may include two long frames 10 extending along a first direction X, and two short frames 20 extending along a second direction Y. The two long frames 10 and the two short frames 20 are alternately connected end to end to form a closed rectangular shape. The two short frames 20 may be the top frame 21 and the bottom frame 22 of the mobile phone, and the two long frames may be the left frame and the right frame of the mobile phone. For example, a curved corner may be formed between the long frames 10 and the short frames 20, so that the planar shape of the mobile phone can be a rounded rectangle.

[0118] The mobile phone 100 may include multiple buttons. For example, the mobile phone 100 may include a lock screen button 31, a volume + button 32, a volume - button 33, and the like. The volume + button 32 and the volume - button 33 may be located on the same long frame 10; the lock screen button 31 may be located on the same long frame 10 as the volume + button 32, or on a different long frame 10. Furthermore, the lock screen button 31 may also be located on the short frame 20.

[0119] The mobile phone 100 may also include multiple openings. For example, as shown in FIG2 , the openings on the bottom frame 22 may include a microphone opening 41, a speaker opening 42, and an external port. The microphone inside the mobile phone communicates with the external environment of the mobile phone through the microphone opening 41 to collect sounds from the external environment. The sound outlet of the speaker module inside the mobile phone communicates with the speaker opening 42 to broadcast sounds to the external environment of the mobile phone.

[0120] The mobile phone may further include a processing chip, which may be a system on chip (SOC), a micro control unit (MCU), or other suitable chips with data processing functions, which are not limited in this application.

[0121] The external ports of a mobile phone may include a Type-C port, micro USB, or other suitable external ports. The pins in the external port can be coupled to the processing chip via the phone's internal signal lines to enable functions such as fast charging and data exchange. For ease of understanding, the following description uses the example of an external port including a Type-C port and a processing chip being a SOC, but this should not be construed as limiting the terms external port and processing chip.

[0122] As shown in FIG2 , the Type-C port 43 can be located on the short bezel 20 at the bottom of the phone. In other examples, the Type-C port can also be located on the short bezel at the top of the phone, or on the long bezel on the left or right side. Furthermore, the number of Type-C ports can be one or more.

[0123] The Type-C port is oval in shape and symmetrically aligned with the phone's short bezel, allowing the Type-C plug to be inserted either head-on or side-on.

[0124] As shown in Figure 3, both Side A and Side B of the Type-C port include 12 pins. Exemplarily, the Type-C interface includes at least two symmetrically arranged VBUS pins (for providing USB voltage, pins 4 and 9), a channel configuration (CC) pin (for detecting connector orientation and determining the type of external device, pin 5, with Side A labeled CC1 and Side B labeled CC2), a D+ pin (pin 6), a D- pin (pin 7), an SBU pin (pin 8 is a spare pin, with Side A labeled SBU1 and Side B labeled SBU2), a TX+ pin (pin 2, with Side A labeled TX1+ and Side B labeled TX2+), a TX- pin (pin 3, with Side A labeled TX1- and Side B labeled TX2-), an RX+ pin (pin 11, with Side A labeled RX2+ and Side B labeled RX1+), an RX- pin (pin 10, with Side A labeled RX2- and Side B labeled RX1-), and a GND pin (for providing a ground signal, pins 1 and 12).

[0125] The protection circuit provided in the embodiments of the present application can be connected to the pins in the Type-C port. Exemplarily, one pin in the Type-C port (e.g., the D+ pin) is connected to a protection circuit. Another exemplary embodiment, multiple pins in the Type-C port (e.g., the D+ pin, the D- pin, and the CC pin) are each connected to a protection circuit. Another exemplary embodiment, each pin in the Type-C port is connected to a protection circuit.

[0126] The structure of the protection circuit connected to each pin in the Type-C port is basically the same. Therefore, the following description will use one pin in the Type-C port connected to one protection circuit as an example. The structures of the protection circuits connected to other pins in the Type-C port can also be referred to in the following description.

[0127] FIG4 shows a schematic diagram of the structure of a protection circuit in a mobile phone.

[0128] As shown in Figure 4, the protection circuit 200 may include a first protection unit 210 and a second protection unit 220. The first protection unit 210 may be coupled to a pin of the Type-C port, and the first protection unit 210 may be coupled to the SOC in the mobile phone. It is understood that the first end of the first protection unit 210 serves as the input end of the protection circuit 200, and the second end of the first protection unit 210 serves as the output end of the protection circuit 200.

[0129] The first end of the second protection unit 220 is coupled to the first end of the first protection unit 210, and the second end of the second protection unit 220 is coupled to the ground terminal GND. It can be understood that the second protection unit 220 is connected in series between the first end of the first protection unit 210 and the ground terminal GND.

[0130] Because the Type-C port of a mobile phone is exposed, it is easy for the Type-C port to introduce EOS from the environment, thereby causing damage to the Type-C port and causing at least some of the Type-C port to lose its functionality. For example, if the Type-C port is used as a charging port with a fast charging function, if the Type-C port is damaged by EOS, the Type-C port will lose its fast charging function as a charging port. For another example, if the Type-C port is used as a data transmission port, if the Type-C port is damaged by EOS, the Type-C port will lose its data transmission function as a data transmission port.

[0131] EOS mainly includes electrostatic stress, surge stress and DC stress. Among them, the electrostatic stress of the Type-C port is mainly due to the stress caused by factors such as friction electrification in the environment. The voltage value corresponding to electrostatic stress is very large and can reach thousands of volts. The surge stress of the Type-C port is the stress caused by the plugging and unplugging of the Type-C plug at the Type-C port. The voltage value corresponding to the surge stress can be more than ten volts to several dozen volts. DC stress is mainly caused by the external conductor (such as liquid seeping into the Type-C port) forming a path between different pins in the Type-C port, resulting in a large DC voltage on the pins and causing stress. The voltage value corresponding to DC stress can be more than ten volts to several dozen volts.

[0132] Among them, electrostatic stress occurs for a shorter time, which is nanosecond level stress; surge stress occurs for a slightly longer time, which is microsecond level stress; and DC stress occurs for the longest time, which is millisecond to second level stress.

[0133] In the embodiments of the present application, when at least one of the above-mentioned electrostatic stress, surge stress and DC stress occurs on the pins of the Type-C port, EOS can avoid damage to the SOC by EOS after being protected by the second protection unit and the first protection unit in sequence.

[0134] As shown in Figure 4, the second protection unit 220 is coupled to the first end a1 of the first protection unit 210. It can be understood that the signal from the pin of the Type-C port first passes through the protection of the second protection unit 220, then passes through the protection of the first protection unit 210, and finally flows from the second end a2 of the first protection unit 210 to the mobile phone chip, thus completing a single signal transmission from the pin of the Type-C port to the SOC.

[0135] The type of stress protection provided by the first protection unit 210 may be different from the type of stress protection provided by the second protection unit 220 .

[0136] The first protection unit 210 can be configured to isolate the SOC from DC stress and / or surge stress on the pins of the Type-C port. Exemplarily, the first protection unit 210 isolates the SOC from DC stress on the pins of the Type-C port. Exemplarily, the first protection unit isolates the SOC from surge stress on the pins of the Type-C port. Exemplarily, the first protection unit isolates the SOC from DC stress and surge stress on the pins of the Type-C port.

[0137] The second protection unit 220 can be configured to reduce electrostatic stress and / or surge stress at the first end a1 of the first protection unit 210. For example, the second protection unit 220 can reduce electrostatic stress at the first end a1 of the first protection unit 210. For another example, the second protection unit 220 can reduce surge stress at the first end a1 of the first protection unit 210. For another example, the second protection unit 220 can reduce electrostatic stress and surge stress at the first end a1 of the first protection unit 210.

[0138] It can be understood that after EOS occurs on the pin of the Type-C port, the second protection unit 220 will first protect the electrostatic stress and / or surge stress of the first end a1 of the first protection unit 210, and then the first protection unit 210 will protect the DC stress and / or surge stress in the EOS, so that after being protected by the first protection unit 210 and the second protection unit 220, the EOS that occurs on the pin of the Type-C port will not cause damage to the SOC.

[0139] In some embodiments, as shown in FIG5 , the first protection unit 210 may include a switch subcircuit 211. A first terminal of the switch subcircuit 211 is coupled to a pin of the Type-C port, and a second terminal of the switch subcircuit 211 is coupled to the SOC. It is understood that the first terminal of the switch subcircuit 211 corresponds to the first terminal a1 of the first protection unit 210, and the second terminal of the switch subcircuit 211 corresponds to the second terminal a2 of the first protection unit 210.

[0140] The switch sub-circuit 211 can disconnect the pins of the Type-C port from the SOC when DC stress and / or surge stress is present on the pins of the Type-C port, isolating the DC stress and / or surge stress from the SOC to protect against EOS and prevent EOS from damaging the SOC. When the pins of the Type-C port do not experience DC stress and / or surge stress, the switch sub-circuit 211 connects the pins of the Type-C port to the SOC, completing the transmission of signals from the pins of the Type-C port to the SOC.

[0141] In some examples, the switch sub-circuit 211 can detect whether DC stress and / or surge stress are present on the pins of the Type-C port. For example, DC stress and / or surge stress correspond to relatively large voltage values, so the switch sub-circuit 211 can determine whether DC stress and / or surge stress are present on the pins of the Type-C port by detecting the voltage at the first terminal of the switch sub-circuit 211.

[0142] When detecting that the voltage at the first terminal a1 of the switch subcircuit 211 is greater than or equal to a preset threshold, the switch subcircuit 211 determines that a DC stress and / or a surge stress exists at the voltage at the first terminal a1 of the switch subcircuit 211, and disconnects the first terminal a2 of the switch subcircuit 211 from the second terminal a2 of the switch subcircuit 211, thereby disconnecting the connection between the pin of the Type-C port and the SOC, isolating the DC stress and / or surge stress from the SOC, thereby achieving protection against EOS and preventing EOS from damaging the SOC.

[0143] When the switch subcircuit 211 detects that the voltage at the first end a1 of the switch subcircuit 211 is less than a preset threshold, it determines that there is no DC stress and / or surge stress at the voltage at the first end a1 of the switch subcircuit 211, maintains conduction between the first end a1 of the switch subcircuit 211 and the second end a2 of the switch subcircuit 211, thereby conducting the connection between the pin of the Type-C port and the SOC, and completing the signal transmission from the pin of the Type-C port to the SOC.

[0144] In other examples, the switch sub-circuit 211 can receive control from other units to disconnect the connection between the pins of the Type-C port and the SOC when there is DC stress and / or surge stress on the pins of the Type-C port, and to connect the connection between the pins of the Type-C port and the SOC when there is no DC stress and / or surge stress on the pins of the Type-C port.

[0145] 6 , the protection circuit 200 may further include a control unit 230. The control unit 230 is coupled to the control terminal a3 of the switch sub-circuit 211. The control unit 230 is configured to provide a control voltage to the control terminal a3 of the switch sub-circuit 211.

[0146] For example, the control unit 230 can detect whether there is DC stress and / or surge stress on the pins of the Type-C port. If there is no DC stress and / or surge stress on the pins of the Type-C port, the control unit 230 can output a first control voltage; if there is DC stress and / or surge stress on the pins of the Type-C port, the control unit 230 can output a second control voltage.

[0147] When the control terminal a3 of the switch sub-circuit 211 receives the first control voltage, the first terminal a1 of the switch sub-circuit 211 and the second terminal a2 of the switch sub-circuit 211 are maintained conductive, thereby conducting the connection between the pin of the Type-C port and the SOC, completing the signal transmission from the pin of the Type-C port to the SOC.

[0148] When the control terminal a3 of the switch sub-circuit 211 receives the second control voltage, the connection between the first terminal a1 of the switch sub-circuit 211 and the second terminal a2 of the switch sub-circuit 211 is disconnected, thereby disconnecting the connection between the pin of the Type-C port and the SOC, isolating the DC stress and / or surge stress from the SOC, achieving protection against EOS and preventing EOS from damaging the SOC.

[0149] As shown in Figure 6, the switch sub-circuit 211 includes a transistor T. The first electrode of the transistor T is coupled to a pin of the Type-C port, the second electrode of the transistor T is coupled to the SOC, and the control electrode of the transistor T is coupled to the control unit 230. It can be understood that the first electrode of the transistor T is equivalent to the first terminal a1 of the switch sub-circuit 211, the second electrode of the transistor T is equivalent to the second terminal a2 of the switch sub-circuit 211, and the control electrode of the transistor T is equivalent to the control terminal a3 of the switch sub-circuit 211.

[0150] The transistor T can be a P-type channel transistor or an N-type channel transistor. The transistor T is an N-type channel transistor as an example for explanation. When there is no DC stress and / or surge stress on the pin of the Type-C port, the control unit 230 can output a high voltage signal (first control voltage), and the control terminal a3 of the switch subcircuit 211 receives the high voltage signal, maintaining the conduction between the first terminal a1 of the switch subcircuit 211 and the second terminal a2 of the switch subcircuit 211, thereby conducting the connection between the pin of the Type-C port and the SOC, and completing the signal transmission from the pin of the Type-C port to the SOC. When DC stress and / or surge stress exists on the pins of the Type-C port, the control unit 230 can output a low voltage signal (second control voltage). The control terminal a3 of the switch sub-circuit 211 receives the low voltage signal, disconnecting the connection between the first terminal a1 of the switch sub-circuit 211 and the second terminal a2 of the switch sub-circuit 211, thereby disconnecting the connection between the pins of the Type-C port and the SOC, isolating the DC stress and / or surge stress from the SOC, achieving protection against EOS, and preventing EOS from damaging the SOC.

[0151] In other examples, the control unit 230 can provide a constant control voltage to the control terminal a3 of the switch sub-circuit 211. For example, the control voltage can be 5V, 6V, 8V, 10V, etc., which is not limited in this application. The transistor T conducts or disconnects the connection between the pin of the Type-C port and the SOC based on the voltage difference between the voltage of the control terminal of the transistor T and the voltage of the second terminal of the transistor T.

[0152] When there is no DC stress and / or surge stress on the pin of the Type-C port, the voltage difference between the voltage of the control electrode of transistor T and the voltage value of the second electrode of transistor T is greater than zero, and transistor T turns on the connection between the first electrode of transistor T and the second electrode of transistor T, thereby turning on the connection between the pin of the Type-C port and the SOC, completing the signal transmission from the pin of the Type-C port to the SOC.

[0153] When DC stress and / or surge stress exists on the pin of the Type-C port, the voltage of the DC stress and / or surge stress is transmitted to the second electrode of the transistor T, so that the voltage of the second electrode of the transistor T is pulled up, and the voltage difference between the voltage of the control electrode of the transistor T and the voltage value of the second electrode of the transistor T is less than zero. The transistor T isolates the connection between the first electrode of the transistor T and the second electrode of the transistor T, thereby disconnecting the connection between the pin of the Type-C port and the SOC, isolating the DC stress and / or surge stress from the SOC, achieving protection against EOS, and preventing EOS from causing damage to the SOC.

[0154] In other embodiments, the first protection unit 210 may also include a capacitor. One plate of the capacitor may be coupled to a pin, and the other plate of the capacitor may be coupled to the mobile phone chip. The capacitor allows AC signals to pass through, while blocking the transmission of DC stress. In other words, the AC signal on the pin can pass through the capacitor to the mobile phone chip, while the DC stress on the pin is blocked by the capacitor and cannot be transmitted to the mobile phone chip.

[0155] In some other embodiments, the first protection unit 210 may also include a switch (e.g., a high-speed switch). The first contact of the switch is used to couple a pin of the Type-C port, and the second contact of the switch is used to couple a mobile phone chip, and the first contact is connected or disconnected with the second contact. The DC stress and / or surge stress of the first end a1 of the first protection unit 210 is isolated from the second end a2 of the first protection unit 210, including: when the voltage of the first contact is greater than or equal to a preset threshold, the first contact is disconnected from the second contact, which is equivalent to disconnecting the connection between the pin of the Type-C port and the SOC, thereby isolating the DC stress and / or surge stress from the SOC, achieving protection against EOS, and preventing EOS from damaging the SOC.

[0156] Of course, the first protection unit 210 may also be other circuit structures that can isolate the mobile phone chip from the DC stress on the pins, and the embodiments of the present application are not limited to this.

[0157] In some embodiments, as shown in FIG5 , the second protection unit 220 may include a first overvoltage protection subcircuit 221. A first terminal of the first overvoltage protection subcircuit 221 is coupled to the first terminal a1 of the first protection unit 210, and a second terminal of the first overvoltage protection subcircuit 221 is coupled to the ground terminal GND. It is understood that the first terminal of the first overvoltage protection subcircuit 221 corresponds to the first terminal b1 of the second protection unit 220, and the second terminal of the first overvoltage protection subcircuit 221 corresponds to the second terminal b2 of the second protection unit 220.

[0158] The first overvoltage protection subcircuit 221 can be in a protection state and a non-protection state. When the first overvoltage protection subcircuit 221 is in the protection state, the first terminal b1 of the first overvoltage protection subcircuit 221 and the second terminal b2 of the first overvoltage protection subcircuit 221 are electrically connected, thereby connecting the first terminal a1 of the first protection unit 210 to the ground terminal GND, thereby pulling down the voltage at the first terminal a1 of the first protection unit 210. When the first overvoltage protection subcircuit 221 is in the non-protection state, the first terminal b1 of the first overvoltage protection subcircuit 221 and the second terminal b2 of the first overvoltage protection subcircuit 221 are isolated, thereby isolating the first terminal a1 of the first protection unit 210 from the ground terminal GND, thereby smoothly transmitting the signal from the pin of the Type-C port to the first protection unit 210.

[0159] Whether the first overvoltage protection subcircuit 221 is in a protection state or a non-protection state may depend on the voltage at the first terminal b1 of the first overvoltage protection subcircuit 221. For example, when the voltage at the first terminal b1 of the first overvoltage protection subcircuit 221 is greater than or equal to a preset first startup voltage, the first overvoltage protection subcircuit 221 may be in a protection state; and when the voltage at the first terminal b1 of the first overvoltage protection subcircuit 221 is less than the first startup voltage, the first overvoltage protection subcircuit 221 may be in a non-protection state.

[0160] As shown in Figure 6, the first overvoltage protection sub-circuit 221 may include a first transient voltage suppressor (TVS1). A first terminal of the first transient voltage suppressor (TVS1) is coupled to the first terminal a1 of the first protection unit 210, and a second terminal of the first transient voltage suppressor (TVS1) is coupled to the ground terminal GND. It is understood that the first terminal of the first transient voltage suppressor (TVS1) corresponds to the first terminal b1 of the first overvoltage protection sub-circuit 221, and the second terminal of the first transient voltage suppressor (TVS1) corresponds to the second terminal b2 of the first overvoltage protection sub-circuit 221.

[0161] The first transient voltage suppressor tube TVS1 may be a unidirectional transient voltage suppressor tube or a bidirectional transient voltage suppressor tube, which is not limited in the embodiments of the present application.

[0162] When the voltage at the first electrode of the first transient voltage suppressor TVS1 is greater than or equal to the preset first starting voltage, the first electrode of the first transient voltage suppressor TVS1 and the second electrode of the first transient voltage suppressor TVS1 are conductively connected, so that the first end a1 of the first protection unit 210 and the ground end GND are conductively connected, thereby pulling down the voltage at the first end a1 of the first protection unit 210.

[0163] When the voltage of the first electrode of the first transient voltage suppressor TVS1 is lower than the preset first starting voltage, the first electrode of the first transient voltage suppressor TVS1 and the second electrode of the first transient voltage suppressor TVS1 are isolated, so that the first end a1 of the first protection unit 210 is isolated from the ground end GND, so that the signal of the pin of the Type-C port is smoothly transmitted to the first protection unit 210.

[0164] It is understood that the first startup voltage can be understood as the turn-on voltage of the first transient voltage suppressor (TVS1). Furthermore, the first transient voltage suppressor (TVS1) also includes a clamping voltage (also known as a limiting voltage), which refers to the maximum voltage allowed to be transmitted from the first terminal of the first transient voltage suppressor (TVS1) to the first terminal a1 of the first protection unit 210 after conduction between the first terminal of the first transient voltage suppressor (TVS1) and the second terminal of the first transient voltage suppressor (TVS1). The clamping voltage of the first transient voltage suppressor (TVS1) is lower than the turn-on voltage of the first transient voltage suppressor (TVS1).

[0165] In some cases, the first startup voltage is greater than the turn-on voltage of a single transient voltage suppressor (TVS). Therefore, as shown in FIG7 , the first overvoltage protection subcircuit 221 may include a transient voltage suppressor (TVS) assembly U-TVS. The first end of the transient voltage suppressor assembly U-TVS is coupled to the first end a1 of the first protection unit 210, and the second end of the transient voltage suppressor assembly U-TVS is coupled to the ground terminal GND. It can be understood that the first end of the transient voltage suppressor assembly U-TVS corresponds to the first end b1 of the first overvoltage protection subcircuit 221, and the second end of the transient voltage suppressor assembly U-TVS corresponds to the second end b2 of the first overvoltage protection subcircuit 221.

[0166] The transient voltage suppressor assembly U-TVS may include a plurality of second transient voltage suppressor tubes TVS2 connected in series. A first electrode of a first second transient voltage suppressor tube TVS2 among the plurality of second transient voltage suppressor tubes TVS2 is coupled to the first terminal a1 of the first protection unit 210, a first electrode of a second second transient voltage suppressor tube TVS2 is coupled to the second electrode of the first second transient voltage suppressor tube TVS2, and so on, until a second electrode of a last second transient voltage suppressor tube TVS2 is coupled to the ground terminal GND.

[0167] Multiple second transient voltage suppressor diodes (TVS2) are connected in series, so the same current flows through each second transient voltage suppressor diode (TVS2). By connecting multiple second transient voltage suppressor diodes (TVS2) in series, the sum of the threshold voltages of each second transient voltage suppressor diode (TVS2) can be used as the threshold voltage of the entire transient voltage suppressor diode assembly (U-TVS). Therefore, if the voltage of a single transient voltage suppressor diode (TVS2) is lower than the first threshold voltage, the threshold voltage of the transient voltage suppressor diode assembly (U-TVS) can be equalized to the first threshold voltage by connecting multiple transient voltage suppressors in series, thus achieving overvoltage protection.

[0168] 7 , the transient voltage suppressor tube assembly U-TVS may include two second transient voltage suppressor tubes TVS2. Of course, in other examples, the transient voltage suppressor tube assembly U-TVS may also include more second transient voltage suppressor tubes TVS2.

[0169] In some embodiments, the first startup voltage can be greater than the voltage corresponding to the DC stress. It is understood that when DC stress is present on the pins of the Type-C port, since the voltage corresponding to the DC stress is less than the first startup voltage, the second protection unit 220 is not activated, and the DC stress is directly transmitted to the first protection unit 210.

[0170] As previously explained, the duration of DC stress is much longer than that of electrostatic stress. While the second protection unit 220 can protect against electrostatic stress with a higher voltage but a shorter duration, it may not be able to withstand DC stress with a longer duration. Therefore, DC stress can damage the second protection unit 220. Therefore, in this embodiment, by designing the first startup voltage to be greater than the voltage corresponding to DC stress, it is possible to prevent DC stress from activating the second protection unit 220, thereby preventing damage to the second protection unit 220 caused by DC stress. This improves the reliability of the second protection unit 220 and the reliability of the protection circuit 200.

[0171] In some other embodiments, the second protection unit 220 may also include a varistor, one end of which may be coupled to the first end of the first protection unit 210 , and the other end of which may be coupled to the ground terminal GND.

[0172] By utilizing the nonlinear characteristics of the varistor, when excessive electrostatic stress and / or surge stress appears on the pin, the varistor can clamp the voltage to a relatively fixed and low voltage value, thereby reducing the electrostatic stress and / or surge stress at the first end of the first protection unit 210.

[0173] Of course, the second protection unit 220 can also be other circuit structures that can reduce electrostatic stress and / or surge stress, such as a buck circuit that can step down the voltage corresponding to electrostatic stress and / or surge stress, etc. The embodiments of the present application are not limited to this.

[0174] FIG8 shows a schematic structural diagram of another protection circuit in a mobile phone.

[0175] 8 , the protection circuit 200 may further include a third protection unit 240. A first terminal c1 of the third protection unit 240 is coupled to the second terminal a2 of the first protection unit 210, and a second terminal c2 of the third protection unit 240 is coupled to the ground terminal GND.

[0176] In some embodiments, in order to prevent DC stress from damaging the second protection unit 220, the startup voltage of the second protection unit 220 is increased, which will cause the clamping voltage of the second protection unit 220 to also increase, resulting in the clamping voltage of the second protection unit 220 being higher than the safety voltage of the SOC.

[0177] Therefore, the third protection unit 240 can further protect the surge stress and / or electrostatic stress protected by the second protection unit 220 to ensure that the surge stress and / or electrostatic stress protected by the third protection unit 240 is less than or equal to the safety voltage of the SOC, thereby improving the protection performance of the protection circuit 200 against the SOC.

[0178] In other embodiments, even if the clamping voltage of the second protection unit 220 is less than or equal to the safety voltage of the SOC, the third protection unit 240 can further improve the performance of the protection circuit 200 in protecting against surge stress and / or electrostatic stress.

[0179] When there is no surge stress and / or electrostatic stress on the pin of the Type-C port, or when there is surge stress and / or electrostatic stress on the pin of the Type-C port and the second protection unit 220 reduces the voltage of the surge stress and / or electrostatic stress to less than the preset second starting voltage, the voltage of the first end c1 of the third protection unit 240 is less than the preset second starting voltage, the first end c1 of the third protection unit 240 and the second end c2 of the third protection unit 240 are disconnected, so that the second end a2 of the first protection unit 210 is disconnected from the ground terminal GND, so that the signal output from the second end a2 of the first protection unit 210 is smoothly transmitted to the SOC and provided to the SOC.

[0180] When surge stress and / or electrostatic stress exists on the pin of the Type-C port and the second protection unit 220 reduces the voltage of the surge stress and / or electrostatic stress but is still greater than or equal to the second startup voltage, the voltage of the first end c1 of the third protection unit 240 is greater than or equal to the second startup voltage, and the first end c1 of the third protection unit 240 and the second end c2 of the third protection unit 240 are conductively connected, so that the second end a2 of the first protection unit 210 is conductively connected to the ground end GND, thereby pulling down the voltage of the second end a2 of the first protection unit 210, ensuring that the surge stress and / or electrostatic stress protected by the third protection unit 240 is less than or equal to the safety voltage of the SOC, thereby improving the protection performance of the protection circuit for the SOC.

[0181] It should be noted that the second startup voltage corresponding to the third protection unit 240 is lower than the first startup voltage corresponding to the second protection unit 220. For example, the second startup voltage corresponding to the third protection unit 240 is lower than the clamping voltage corresponding to the second protection unit 220. Furthermore, the output voltage corresponding to the second terminal c2 of the third protection unit 240 can be lower than or equal to the safety voltage of the SOC.

[0182] As shown in FIG9 , the third protection unit 240 may include a second overvoltage protection subcircuit 241. The connection relationship between the second overvoltage protection subcircuit 241 and the third protection unit 240 may refer to the connection relationship between the first overvoltage protection subcircuit 221 and the second protection unit 220; similarly, the operation process of the second overvoltage protection subcircuit 241 may refer to the operation process of the first overvoltage protection subcircuit 221; this application will not further describe this.

[0183] As shown in FIG10 , the second overvoltage protection subcircuit 241 may include a third transient voltage suppressor (TVS3). The connection relationship between the third transient voltage suppressor (TVS3) and the second overvoltage protection subcircuit 241 can refer to the connection relationship between the third transient voltage suppressor (TVS3) and the second overvoltage protection subcircuit 241. Similarly, the operation process of the third transient voltage suppressor (TVS3) can refer to the operation process of the first transient voltage suppressor (TVS1); this application will not further describe this.

[0184] In other examples, the second overvoltage protection subcircuit 241 may also include multiple transient voltage suppressors. In this case, the connection relationship and operating principle of the multiple transient voltage suppressors can refer to the connection relationship and operating principle of the multiple second transient voltage suppressors TVS2 in the transient voltage suppressor assembly U-TVS, and will not be repeated here.

[0185] FIG11 shows a schematic structural diagram of the protection circuit shown in FIG10 applied to the D+ pin and the D- pin of the Type-C port.

[0186] In some examples, the protection circuit 200 is coupled to the D+ and D- pins of a Type-C port. As shown in Figure 11, an inductor L1 may be included between the D- pin and the protection circuit 200a, and an inductor L2 may be included between the D+ pin and the protection circuit 200b. The first end d1 of the inductor L1 is coupled to the D- pin, and the second end d2 of the inductor L1 is coupled to the first end b1 of the second protection unit 220 in the protection circuit 200a. The first end d3 of the inductor L2 is coupled to the D+ pin, and the second end d4 of the inductor L2 is coupled to the first end b1 of the second protection unit 220 in the protection circuit 200b.

[0187] The circular ring between inductor L1 and inductor L2 represents the magnetic ring shared by inductor L1 and inductor L2. Inductor L1, inductor L2, and the magnetic ring together constitute the common-mode inductor DL. Common-mode inductor DL ​​filters common-mode electromagnetic interference signals. As you can see, inductor L1 filters electromagnetic interference signals from the D- pin of the Type-C port; similarly, inductor L2 filters electromagnetic interference signals from the D+ pin of the Type-C port. This improves the reliability of signal transmission on the Type-C port.

[0188] Figure 12 shows a schematic diagram of the structure of a mobile phone without a protection circuit between the pin of the Type-C port and the SOC; Figure 13 shows a schematic diagram of the structure of a mobile phone with a second protection unit and no first protection unit between the pin of the Type-C port and the SOC; Figure 14 is a schematic diagram of the structure of the circuit in Figure 13 using the D+ pin of the Type-C port;

[0189] FIG15 shows a schematic structural diagram of a mobile phone including a first protection unit and excluding a second protection unit between the pin of the Type-C port and the SOC.

[0190] The following compares the protection effects of various circuits between a pin of the Type-C port in a mobile phone and the SoC.

[0191] In Figure 12, one pin of the Type-C port is directly coupled to the SOC, without either the first or second protection unit. This allows electrostatic stress, surge stress, and DC stress to be transmitted directly from the pin to the SOC, damaging it.

[0192] In FIG. 13 , one pin of the Type-C port is directly coupled to the SOC, wherein FIG. 13 further includes a second protection unit 220 but does not include the first protection unit 210 .

[0193] When the turn-on voltage of the second protection unit 220 is greater than the voltage corresponding to the DC stress (less than the voltage corresponding to the surge stress and the voltage corresponding to the electrostatic stress), the surge stress and / or DC stress can turn on the second protection unit 220, and the second protection unit 220 can conduct the surge stress and / or electrostatic stress to the ground terminal GND, thereby pulling down the voltage corresponding to the surge stress and / or electrostatic stress, thereby realizing protection against surge stress and / or electrostatic stress on the pins of the Type-C port, and preventing surge stress and / or electrostatic stress from damaging the SOC.

[0194] However, the DC stress does not activate the second protection unit 220 , and the DC stress may be directly transmitted from the pins of the Type-C port to the SOC, causing damage to the SOC.

[0195] If the activation voltage of the second protection unit 220 is lower than the voltage corresponding to DC stress (lower than the voltage corresponding to surge stress and the voltage corresponding to electrostatic stress), the DC stress can activate the second protection unit 220. However, the second protection unit 220 cannot withstand the DC stress for a long time and may be damaged. The DC stress can still be directly transmitted from the pins of the Type-C port to the SOC, causing damage to the SOC. Moreover, due to the damage to the second protection unit 220, the second protection unit 220 can no longer provide protection against surge stress and / or electrostatic stress on the pins of the Type-C port.

[0196] In some examples, the protection circuit 200 is coupled to the D+ pin of the Type-C port. As shown in FIG14 , an inductor L2 may be included between the D+ pin and the protection circuit 200. A first end d3 of the inductor L2 is coupled to the D+ pin, and a second end d4 of the inductor L2 is coupled to a first end b1 of the second protection unit 220.

[0197] When the activation voltage of the second protection unit 220 is lower than the voltage corresponding to the DC stress (also lower than the voltage corresponding to the surge stress and / or electrostatic stress), the DC stress can activate the second protection unit 220, wherein one of the inductor L2 and the second protection unit 220 may be damaged due to being unable to withstand the DC stress for a long time.

[0198] If the inductor L2 is damaged by DC stress, it will cause a short circuit between the D+ pin and the SoC. This may cause the Type-C port to lose its fast charging and data transmission functions, affecting its normal use.

[0199] If the second protection unit 220 is damaged due to DC stress, the second protection unit 220 may no longer be able to protect the pins of the Type-C port from surge stress and / or electrostatic stress.

[0200] One pin of the Type-C port in FIG15 is directly coupled to the SOC, wherein FIG15 also includes a first protection unit but does not include a second protection unit.

[0201] If DC stress occurs on the pins of the Type-C port, the first protection unit 210 can isolate the connection between the pins of the Type-C port and the SOC, thereby protecting the pins from DC stress. Similarly, if surge stress occurs on the pins of the Type-C port, the first protection unit 210 can also isolate the connection between the pins of the Type-C port and the SOC, thereby protecting the pins from surge stress.

[0202] However, when electrostatic stress occurs on the pins of the Type-C port, since the electrostatic stress occurs for a very short time and the voltage corresponding to the electrostatic stress is very high, the electrostatic stress can be directly transmitted from the pins of the Type-C port to the SOC, causing damage to the SOC.

[0203] The mobile phone in FIG4 includes both a first protection unit and a second protection unit.

[0204] When the activation voltage of the second protection unit 220 is lower than the voltage corresponding to DC stress (lower than the voltage corresponding to surge stress and / or electrostatic stress), the DC stress can activate the second protection unit 220. However, the second protection unit 220 cannot withstand the DC stress for a long time and may be damaged. The first protection unit 210 can isolate the connection between the pins of the Type-C port and the SOC, thereby protecting the pins of the Type-C port from DC stress. However, since the DC stress damages the second protection unit 220, the second protection unit 220 can no longer provide protection against surge stress and / or electrostatic stress on the pins of the Type-C port.

[0205] When the activation voltage of the second protection unit 220 is greater than the voltage corresponding to DC stress (less than the voltage corresponding to electrostatic stress), DC stress does not activate the second protection unit 220. The first protection unit 210 can isolate the connection between the pins of the Type-C port and the SOC, thereby protecting the pins of the Type-C port from DC stress. Similarly, when the activation voltage of the second protection unit 220 is greater than the voltage corresponding to surge stress, the first protection unit 210 can also isolate the connection between the pins of the Type-C port and the SOC, thereby protecting the pins of the Type-C port from surge stress.

[0206] Furthermore, the second protection unit 220 can conduct the electrostatic stress to the ground terminal GND, thereby pulling down the voltage corresponding to the electrostatic stress at the first terminal a1 of the first protection unit 210, thereby protecting the pins of the Type-C port from electrostatic stress. Similarly, when the turn-on voltage of the second protection unit 220 is lower than the voltage corresponding to the surge stress, the second protection unit 220 can conduct the surge stress to the ground terminal GND, thereby pulling down the voltage corresponding to the surge stress at the first terminal a1 of the first protection unit 210, thereby protecting the pins of the Type-C port from surge stress.

[0207] However, since the turn-on voltage of the second protection unit 220 is relatively large, the clamping voltage corresponding to the second protection unit 220 may also be relatively large and exceed the safety voltage of the SOC. In this way, the voltage corresponding to the surge stress and / or electrostatic stress after protection by the second protection unit 220 may be greater than the safety voltage of the SOC, thereby causing damage to the SOC.

[0208] FIG8 includes a first protection unit, a second protection unit and a third protection unit.

[0209] The turn-on voltage of the second protection unit 220 is greater than the voltage corresponding to the DC stress, and the clamping voltage of the second protection unit 220 is greater than the safety voltage of the SOC. The turn-on voltage of the third protection unit 240 is less than the turn-on voltage of the second protection unit 220 and less than the clamping voltage of the second protection unit 220, and the clamping voltage of the third protection unit 240 is less than or equal to the safety voltage of the SOC.

[0210] When electrostatic stress occurs on the pins of the Type-C port, the second protection unit 220 can be activated, causing the second protection unit 220 to pull down the voltage corresponding to the electrostatic stress at the first end a1 of the first protection unit 210 (this voltage is greater than the safety voltage of the SOC). After that, the electrostatic stress caused by the pull-down is transmitted to the second end a2 of the first protection unit 210, and the third protection unit 240 is activated, causing the third protection unit 240 to pull down the voltage corresponding to the electrostatic stress at the second end a2 of the first protection unit 210, so that the voltage corresponding to the electrostatic stress after the second pull-down is less than the safety voltage of the SOC. In this way, it is possible to protect the pins of the Type-C port from electrostatic stress and prevent damage to the SOC caused by electrostatic stress.

[0211] When surge stress occurs on the pins of the Type-C port:

[0212] If the voltage corresponding to the surge stress is greater than the turn-on voltage of the second protection unit 220, the second protection unit 220 is activated, causing it to pull down the voltage corresponding to the surge stress at the first terminal a1 of the first protection unit 210 (this voltage is greater than the safe voltage of the SOC). The surge stress generated by this pull-down is then transmitted to the second terminal a2 of the first protection unit 210, and the third protection unit 240 is activated, causing it to pull down the voltage corresponding to the surge stress at the second terminal a2 of the first protection unit 210. This ensures that the voltage corresponding to the surge stress after the second pull-down is less than the safe voltage of the SOC. This protects the pins from surge stress and prevents damage to the SOC caused by surge stress.

[0213] If the voltage corresponding to the surge stress is lower than the activation voltage of the second protection unit 220, the second protection unit 220 is not activated. The surge stress is transmitted to the second end a2 of the first protection unit 210, activating the first protection unit 210. The first protection unit 210 can isolate the connection between the Type-C port pins and the SOC, isolating the surge stress from the SOC and preventing the surge stress from being transmitted to the SOC. This protects the Type-C port pins from surge stress and prevents damage to the SOC caused by surge stress.

[0214] When DC stress occurs on the pin, the first protection unit 210 is activated. The first protection unit 210 can isolate the connection between the pin of the Type-C port and the SOC, so that the DC stress is isolated from the SOC and prevented from being transmitted to the SOC, thereby protecting the pin from DC stress and preventing damage to the SOC caused by DC stress.

[0215] From the above comparison, it can be known that only when the protection circuit 200 includes at least the first protection unit 210 and the second protection unit 220 at the same time, the protection circuit 200 can fully protect against the electrostatic stress, surge stress and DC stress in EOS, thereby preventing the EOS appearing on the pins of the Type-C port from damaging the SOC.

[0216] In addition, by adding the third protection unit 240, the protection circuit 200 can increase the turn-on voltage of the second protection unit 220 while ensuring the protection effect of the protection circuit 200 against EOS, thereby preventing DC stress from damaging the second protection unit 220, thereby improving the reliability of the protection circuit 200.

[0217] FIG16 shows a schematic structural diagram of a mobile phone; FIG17 shows a schematic structural diagram of another mobile phone.

[0218] The mobile phone may include at least one circuit board. For example, the mobile phone may include one circuit board (such as a main board), or the mobile phone may include multiple circuit boards.

[0219] In some examples, as shown in FIG16 , the aforementioned protection circuit 200 is all located on a single circuit board (circuit board 2). Furthermore, the pins on the Type-C port and the SoC may also be located on the same circuit board. It is understood that the pins on the Type-C port, the SoC, and the protection circuit 200 connecting the pins and the SoC, respectively, are all located on the same circuit board (circuit board 2).

[0220] In other examples, a mobile phone may include two circuit boards. The mobile phone may include circuit board 1 and circuit board 2. The area of ​​circuit board 1 may be smaller than the area of ​​circuit board 2, or may be equal to or larger than the area of ​​circuit board 2, and this application does not limit this.

[0221] For example, as shown in FIG16 , the pins on the Type-C port may be located on circuit board 1 , and the above-mentioned protection circuits may be located on circuit board 2 .

[0222] For another example, as shown in Figure 17, the second protection unit 220 can be located on circuit board 1, and the first protection unit 210 can be located on circuit board 2. In addition, the pins on the Type-C port can be located together with the second protection unit 220 on circuit board 1, and the SOC can be located together with the first protection unit 210 on circuit board 2.

[0223] As shown in Figures 16 and 17, the mobile phone may further include a flexible printed circuit (FPC) 300. The FPC 300 may connect two circuit boards, for example, the FPC may connect circuit board 1 and circuit board 2 respectively.

[0224] FPC 300 can include multiple signal lines, each of which can be coupled to a signal interface on two adjacent circuit boards, allowing signals to be transmitted outside the two circuit boards, achieving cross-circuit board signal transmission. Furthermore, due to the FPC's flexibility, it does not restrict the layout of the two connected circuit boards, facilitating space design within the phone.

[0225] The above is only a specific embodiment of the present application, but the scope of protection of this application is not limited to this. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A protection circuit, applied to an electronic device having an external port and a processing chip, characterized in that: The protection circuit comprises: a first protection unit and a second protection unit; The first end of the first protection unit is used to couple a pin of the external port, and the second end of the first protection unit is used to couple the processing chip; the first protection unit is configured to isolate the DC stress and / or surge stress of the first end of the first protection unit from the second end of the first protection unit; The first end of the second protection unit is coupled to the first end of the first protection unit, and the second end of the second protection unit is coupled to the ground end; the second protection unit is configured to reduce surge stress and / or electrostatic stress at the first end of the first protection unit.

2. The protection circuit according to claim 1, characterized in that: The first protection unit includes a switch subcircuit; a first end of the switch subcircuit is used to couple a pin of the external port, and a second end of the switch subcircuit is used to couple the processing chip; The step of isolating the DC stress and / or surge stress at the first end of the first protection unit from the second end of the first protection unit includes isolating the first end of the switch sub-circuit from the second end of the switch sub-circuit.

3. The protection circuit according to claim 2, characterized in that: The method of isolating the DC stress and / or surge stress at the first end of the first protection unit from the second end of the first protection unit includes: when the voltage at the first end of the switch subcircuit is greater than or equal to a preset threshold, isolating the first end of the switch subcircuit from the second end of the switch subcircuit.

4. The protection circuit according to claim 2 or 3, characterized in that: The protection circuit further comprises a control unit; the switch subcircuit comprises a transistor; The first electrode of the transistor is used to couple to a pin of the external port, the second electrode of the transistor is used to couple to the processing chip, and the control electrode of the transistor is coupled to the control unit; The isolating the first end of the switch subcircuit from the second end of the switch subcircuit includes: isolating the first electrode of the transistor from the second electrode of the transistor.

5. The protection circuit according to claim 1, characterized in that: The first protection unit includes a capacitor; a first plate of the capacitor is used to couple a pin of the external port, and a second plate of the capacitor is used to couple the processing chip; The step of isolating the DC stress and / or surge stress at the first end of the first protection unit from the second end of the first protection unit includes: isolating the DC stress at the first plate of the capacitor from the second plate of the capacitor.

6. The protection circuit according to claim 1, characterized in that: The first protection unit includes a switch; a first contact of the switch is used to couple a pin of the external port, a second contact of the switch is used to couple the processing chip, and the first contact is connected or disconnected with the second contact; The method of isolating the DC stress and / or surge stress at the first end of the first protection unit from the second end of the first protection unit includes: when the voltage of the first contact is greater than or equal to a preset threshold, the first contact is disconnected from the second contact, and the DC stress and / or surge stress of the first contact is isolated from the second contact.

7. The protection circuit according to any one of claims 1 to 6, characterized in that: The second protection unit includes a first overvoltage protection subcircuit; A first end of the first overvoltage protection subcircuit is coupled to a first end of the first protection unit, and a second end of the first overvoltage protection subcircuit is coupled to the ground end; The method of reducing the surge stress and / or electrostatic stress at the first end of the first protection unit includes: when the voltage at the first end of the first overvoltage protection subcircuit is greater than or equal to a preset first starting voltage, the first end of the first overvoltage protection subcircuit is connected to the second end of the first overvoltage protection subcircuit to reduce the voltage at the first end of the first protection unit.

8. The protection circuit according to claim 7, characterized in that: The first overvoltage protection subcircuit includes a first transient voltage suppression tube; a first electrode of the first transient voltage suppression tube is coupled to a first end of the first protection unit, and a second electrode of the first transient voltage suppression tube is coupled to the ground end; The first end of the first overvoltage protection subcircuit is connected to the second end of the first overvoltage protection subcircuit, including: connecting the first pole of the first transient voltage suppression tube to the second pole of the first transient voltage suppression tube.

9. The protection circuit according to claim 7, characterized in that: The first overvoltage protection subcircuit includes a transient voltage suppression tube assembly; a first end of the transient voltage suppression tube assembly is coupled to a first end of the first protection unit, and a second end of the transient voltage suppression tube assembly is coupled to the ground end; The transient voltage suppression tube assembly includes a plurality of second transient voltage suppression tubes connected in series.

10. The protection circuit according to any one of claims 1 to 9, characterized in that: The protection circuit further includes a third protection unit; The first end of the third protection unit is coupled to the second end of the first protection unit, and the second end of the third protection unit is coupled to the ground end; the third protection unit is configured to reduce the surge stress and / or the electrostatic stress of the second end of the first protection unit.

11. The protection circuit according to claim 10, characterized in that: The third protection unit includes a second overvoltage protection subcircuit; The first end of the second overvoltage protection subcircuit is coupled to the second end of the first protection unit, and the second end of the second overvoltage protection subcircuit is coupled to the ground end; The reducing the surge stress and / or the electrostatic stress at the second end of the first protection unit includes: when the voltage at the first end of the second overvoltage protection subcircuit is greater than or equal to a preset second starting voltage, the first end of the second overvoltage protection subcircuit is connected to the second end of the second overvoltage protection subcircuit to reduce the voltage at the second end of the first protection unit.

12. The protection circuit according to claim 11, characterized in that: The protection circuit also includes a first overvoltage protection subcircuit; The second startup voltage corresponding to the second overvoltage protection subcircuit is lower than the first startup voltage corresponding to the first overvoltage protection subcircuit.

13. The protection circuit according to claim 11 or 12, characterized in that: The second overvoltage protection subcircuit includes a third transient voltage suppression tube; a first electrode of the third transient voltage suppression tube is coupled to the second end of the first protection unit, and a second electrode of the third transient voltage suppression tube is coupled to the ground end; The first end of the second overvoltage protection subcircuit is connected to the second end of the second overvoltage protection subcircuit, including: connecting the first pole of the third transient voltage suppression tube to the second pole of the third transient voltage suppression tube; Pass.

14. An electronic device, characterized in that: include: An external port, a processing chip, and a protection circuit coupled to the external port and the processing chip respectively; The protection circuit is the protection circuit according to any one of claims 1 to 13.

15. The electronic device according to claim 14, characterized in that: The external port includes a plurality of pins; One of the pins is coupled to the protection circuit and coupled to the processing chip through the protection circuit; or, The plurality of pins are respectively coupled to different protection circuits, and each pin is coupled to the processing chip by using the connected protection circuits.

16. The electronic device according to claim 14 or 15, characterized in that: The external port includes at least one of a universal serial bus (USB) port, a high-definition multimedia interface (HDMI), and a network card interface.

17. The electronic device according to any one of claims 14 to 16, characterized in that: The processing chip includes a system-on-chip (SOC) or a microcontroller unit (MCU).

18. The electronic device according to any one of claims 14 to 17, characterized in that: The electronic device comprises at least one circuit board; The first protection unit and the second protection unit in the protection circuit are located on the same circuit board; or, The first protection unit and the second protection unit in the protection circuit are respectively located on different circuit boards.

19. The electronic device according to any one of claims 14 to 18, characterized in that: The external port includes a Type-C port, and the Type-C port includes a D+ pin and a D- pin; The electronic device further includes a common mode inductor, which includes a magnetic ring, and a first inductor coil and a second inductor coil respectively wound around the magnetic ring; a first end of the first inductor coil is coupled to the D- pin, and a first end of the second inductor coil is coupled to the D+ pin; The electronic device also includes two protection circuits; in one protection circuit, the first end of the first protection unit is coupled to the second end of the first inductor coil, and the second end of the first protection unit is coupled to the processing chip; in the other protection circuit, the first end of the first protection unit is coupled to the second end of the second inductor coil, and the second end of the first protection unit is coupled to the processing chip.

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