Patent Publication Number: US-2020295760-A1

Title: Interface Circuit

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Patent Application No. PCT/CN2018/085458, filed on May 3, 2018, which claims priority to Chinese Patent Application No. 201711236410.6, filed on Nov. 30, 2017, both of which are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     This application relates to the field of electronic technologies, and in particular, to an interface circuit. 
     BACKGROUND 
     With development of electronic technologies, to enable a chip to have more functions and consume less power, a plurality of power domain circuits are usually disposed in the chip. The plurality of power domain circuits use power supply solutions independent of each other, or in other words, the plurality of power domain circuits have different power supply circuits. Each power domain circuit has a turnover voltage. The turnover voltage of each power domain circuit is less than a voltage of a power supply of the power domain circuit and greater than a voltage of a reference ground of the power domain circuit. For an analog signal in a power domain circuit, if a voltage of the analog signal at a moment is greater than a turnover voltage of the power domain circuit, the analog signal is at a logical high level at this moment. If a voltage of the analog signal at a moment is smaller than the turnover voltage of the power domain circuit, the analog signal is at a logical low level at this moment. Generally, the logical high level is provided by a power supply of the power domain circuit, and the logical low level is provided by a reference ground of the power domain circuit. 
     In actual application, a signal cable, a power cable, a ground cable, and the like in the chip are prone to electrostatic interference in a plugging or unplugging process or in a normal working process. The voltage of the power supply and the voltage of the reference ground of each power domain circuit in the chip change greatly due to the electrostatic interference. Consequently, the turnover voltage of each power domain circuit changes greatly. For example, when a signal cable in a power domain circuit is interfered with by positive static electricity, both a voltage of a power supply and a voltage of a reference ground of the power domain circuit increase, and consequently, a turnover voltage of the power domain circuit also increases. Alternatively, when a signal cable in a power domain circuit is interfered with by negative static electricity, both a voltage of a power supply and a voltage of a reference ground of the power domain circuit decrease, and consequently, a turnover voltage of the power domain circuit also decreases. 
     In this case, if another power domain circuit transmits a signal to the power domain circuit interfered with by the static electricity, a logical level of the signal is very likely to be incorrectly transmitted. For example, a signal transmitted by a first power domain circuit to a second power domain circuit is at a logical high level. In an embodiment, a voltage of the signal is a voltage of a power supply of the first power domain circuit. In this case, if a turnover voltage of the second power domain circuit increases due to interference of positive static electricity and exceeds the voltage of the power supply of the first power domain circuit, the signal that is input from the first power domain circuit and that is originally at the logical high level is incorrectly considered to be at a logical low level in the second power domain circuit. For another example, a signal transmitted by the first power domain circuit to the second power domain circuit is at a logical low level. In an embodiment, a voltage of the signal is a voltage of a reference ground of the first power domain circuit. In this case, if a turnover voltage of the second power domain circuit decreases due to interference of negative static electricity and is smaller than the voltage of the reference ground of the first power domain circuit, the signal that is input from the first power domain circuit and that is originally at the logical low level is incorrectly considered to be at a logical high level in the second power domain circuit. 
     To resolve the foregoing problem, currently, an electrostatic discharge (ESD) capability is usually added to the chip. For example, an ESD device, such as a transient voltage suppressor (TVS) diode or a series resistor, may be added outside the chip to directly discharge outside the chip static electricity interfering with the chip such that the static electricity does not affect an internal circuit of the chip. Alternatively, a quantity of output pins (pin) of the ground cable in the chip may be increased to enhance an electrostatic discharge capability of the ground cable such that a voltage of the ground cable does not become excessively high or excessively low due to electrostatic interference. However, these methods all increase packaging costs and an area of the chip, thereby affecting an application range of the chip. 
     SUMMARY 
     To resolve a problem in a related technology that a logical level of a signal is incorrectly transmitted, this application provides an interface circuit. The technical solutions are as follows. 
     According to a first aspect, an interface circuit is provided, including a phase inverter. 
     An input end of the phase inverter is connected to a signal output end of a first power domain circuit, and an output end of the phase inverter is connected to a signal input end of a second power domain circuit. 
     A power end of the phase inverter is connected to a power supply of the first power domain circuit, and a ground end of the phase inverter is connected to a reference ground of the second power domain circuit. Alternatively, a power end of the phase inverter is connected to a power supply of the second power domain circuit, and a ground end of the phase inverter is connected to a reference ground of the first power domain circuit. 
     Normally, a voltage of the power end of the phase inverter is greater than a voltage of the ground end of the phase inverter. In this case, if a voltage of the input end of the phase inverter is greater than a turnover voltage of the phase inverter, a voltage of the output end of the phase inverter is the voltage of the ground end of the phase inverter. If a voltage of the input end of the phase inverter is less than a turnover voltage of the phase inverter, a voltage of the output end of the phase inverter is the voltage of the power end of the phase inverter. The turnover voltage of the phase inverter is a voltage between the voltage of the power end of the phase inverter and the voltage of the ground end of the phase inverter. 
     It should be noted that the phase inverter is configured for transition between logical states of a signal. Further, the phase inverter is configured to, when an input signal is at a logical high level (that is, in a logical state “1”), output a signal at a logical low level (that is, in a logical state “0”), or when an input signal is at a logical low level, output a signal at a logical high level. 
     In addition, for a power domain circuit, a voltage of a signal that is output by the power domain circuit at a logical high level is a voltage of a power supply of the power domain circuit, and a voltage of a signal that is output by the power domain circuit at a logical low level is a voltage of a reference ground of the power domain circuit. 
     In this embodiment of the present disclosure, when the power end of the phase inverter is connected to the power supply of the first power domain circuit, and the ground end of the phase inverter is connected to the reference ground of the second power domain circuit, if a signal transmitted by the signal output end of the first power domain circuit to the input end of the phase inverter is at a logical high level, the voltage of the input end of the phase inverter is equal to the voltage of the power end of the phase inverter. Therefore, provided that a voltage, after increasing, of the reference ground of the second power domain circuit does not exceed the voltage of the power supply of the first power domain circuit, the voltage of the power end of the phase inverter is greater than the voltage of the ground end of the phase inverter, and the voltage of the input end of the phase inverter is greater than the turnover voltage of the phase inverter. In this case, the voltage of the output end of the phase inverter is the voltage of the ground end of the phase inverter. In an embodiment, a voltage of a signal transmitted by the output end of the phase inverter to the signal input end of the second power domain circuit is the voltage of the reference ground of the second power domain circuit. In this way, the signal that is input to the signal input end of the second power domain circuit is at a logical low level in the second power domain circuit, thereby ensuring correct transmission of the logical level of the signal. 
     In addition, when the power end of the phase inverter is connected to the power supply of the second power domain circuit, and the ground end of the phase inverter is connected to the reference ground of the first power domain circuit, if a signal transmitted by the signal output end of the first power domain circuit to the input end of the phase inverter is at a logical low level, the voltage of the input end of the phase inverter is equal to the voltage of the reference ground of the phase inverter. Therefore, provided that a voltage, after decreasing, of the power supply of the second power domain circuit is not smaller than the voltage of the reference ground of the first power domain circuit, the voltage of the power end of the phase inverter is greater than the voltage of the ground end of the phase inverter, and the voltage of the input end of the phase inverter is less than the turnover voltage of the phase inverter. In this case, the voltage of the output end of the phase inverter is the voltage of the power end of the phase inverter. In an embodiment, a voltage of a signal transmitted by the output end of the phase inverter to the signal input end of the second power domain circuit is the voltage of the power supply of the second power domain circuit. In this way, the signal that is input to the signal input end of the second power domain circuit is at a logical high level in the second power domain circuit, thereby ensuring correct transmission of the logical level of the signal. 
     The phase inverter includes a p-channel metal-oxide-semiconductor (PMOS) transistor and an n-channel metal-oxide-semiconductor (NMOS) transistor. 
     Both a gate of the PMOS transistor and a gate of the NMOS transistor are connected to the signal output end of the first power domain circuit. Both a drain of the PMOS transistor and a drain of the NMOS transistor are connected to the signal input end of the second power domain circuit. 
     A source of the PMOS transistor is connected to the power supply of the first power domain circuit, and a source of the NMOS transistor is connected to the reference ground of the second power domain circuit. Alternatively, a source of the PMOS transistor is connected to the power supply of the second power domain circuit, and a source of the NMOS transistor is connected to the reference ground of the first power domain circuit. 
     In this embodiment of the present disclosure, when the source of the PMOS transistor is connected to the power supply of the first power domain circuit, and the source of the NMOS transistor is connected to the reference ground of the second power domain circuit, if a signal transmitted by the signal output end of the first power domain circuit to the input end of the phase inverter is at a logical high level, voltages applied to the gate of the PMOS transistor and the gate of the NMOS transistor are the voltage of the power supply of the first power domain circuit. In this case, the voltage of the gate of the PMOS transistor is equal to a voltage of the source of the PMOS transistor, and the PMOS transistor is cut off. When a voltage, after increasing, of the reference ground of the second power domain circuit does not exceed the voltage of the power supply of the first power domain circuit, the voltage of the gate of the NMOS transistor is greater than a voltage of the source of the NMOS transistor, and the NMOS transistor is turned on. In this way, a voltage of a connection point between the drain of the PMOS transistor and the drain of the NMOS transistor is the voltage of the reference ground of the second power domain circuit connected to the source of the NMOS transistor. In an embodiment, a voltage of a signal that is input to the signal input end of the second power domain circuit is the voltage of the reference ground of the second power domain circuit. 
     In addition, when the source of the PMOS transistor is connected to the power supply of the second power domain circuit, and the source of the NMOS transistor is connected to the reference ground of the first power domain circuit, if a signal transmitted by the signal output end of the first power domain circuit to the input end of the phase inverter is at a logical low level, voltages applied to the gate of the PMOS transistor and the gate of the NMOS transistor are the voltage of the reference ground of the first power domain circuit. In this case, the voltage of the gate of the NMOS transistor is equal to the voltage of the source of the NMOS transistor, and the NMOS transistor is cut off. When a voltage, after decreasing, of the power supply of the second power domain circuit is not smaller than the voltage of the reference ground of the first power domain circuit, the voltage of the gate of the PMOS transistor is less than the voltage of the source of the PMOS transistor, and the PMOS transistor is turned on. In this way, the voltage of the connection point between the drain of the PMOS transistor and the drain of the NMOS transistor is the voltage of the power supply of the second power domain circuit connected to the source of the PMOS transistor. In an embodiment, a voltage of a signal that is input to the signal input end of the second power domain circuit is the voltage of the power supply of the second power domain circuit. 
     According to a second aspect, an interface circuit is provided, including a NAND gate circuit. 
     There are n input ends of the NAND gate circuit respectively connected to n signal output ends of a plurality of power domain circuits, and an output end of the NAND gate circuit is connected to a signal input end of a target power domain circuit. The n input ends of the NAND gate circuit one-to-one correspond to n power ends of the NAND gate circuit, and n is an integer greater than or equal to 2. 
     An i th  power end of the n power ends of the NAND gate circuit is connected to a power supply of a power domain circuit to which an i th  signal output end of the n signal output ends belongs, a ground end of the NAND gate circuit is connected to a reference ground of the target power domain circuit, and i is an integer greater than or equal to 1 and less than or equal to n. Alternatively, the n power ends of the NAND gate circuit are all connected to a power supply of the target power domain circuit, and a ground end of the NAND gate circuit is connected to a reference ground of a power domain circuit to which a target signal output end of the n signal output ends belongs, and the target signal output end is connected to a target input end of the n input ends of the NAND gate circuit. 
     Normally, a voltage of each of the n power ends of the NAND gate circuit is greater than a voltage of the ground end of the NAND gate circuit. In this case, if a voltage of each of the n input ends of the NAND gate circuit is greater than a turnover voltage of the NAND gate circuit, a voltage of the output end of the NAND gate circuit is the voltage of the ground end of the NAND gate circuit. If a voltage of the target input end of the NAND gate circuit is less than the turnover voltage of the NAND gate circuit, the voltage of the output end of the NAND gate circuit is a voltage of a target power end that is in the n power ends of the NAND gate circuit and that corresponds to the target input end. The turnover voltage of the NAND gate circuit is a voltage between the voltage of the ground end of the NAND gate circuit and a smallest voltage of voltages of the n power ends of the NAND gate circuit. 
     It should be noted that the NAND gate circuit is configured for transition between logical states of a signal. Further, the NAND gate circuit is configured to, when a plurality of input signals are all at a logical high level, output a signal at a logical low level, or when any one of a plurality of input signals is at a logical low level, output a signal at a logical high level. 
     In this embodiment of the present disclosure, when the i th  power end of the n power ends of the NAND gate circuit is connected to the power supply of the power domain circuit to which the i th  signal output end of the n signal output ends belongs, and the ground end of the NAND gate circuit is connected to the reference ground of the target power domain circuit, if signals transmitted by the n signal output ends to the n input ends of the NAND gate circuit are all at a logical high level, a voltage of an i th  input end of the n input ends of the NAND gate circuit is equal to a voltage of the i th  power end of the NAND gate circuit. Therefore, provided that a voltage, after increasing, of the reference ground of the target power domain circuit does not exceed a voltage of a power supply of each of the plurality of power domain circuits, the voltage of each of the n power ends of the NAND gate circuit is greater than the voltage of the ground end of the NAND gate circuit, and the voltage of each of the n input ends of the NAND gate circuit is greater than the turnover voltage of the NAND gate circuit. In this case, the voltage of the output end of the NAND gate circuit is the voltage of the ground end of the NAND gate circuit. In an embodiment, a voltage of a signal transmitted by the output end of the NAND gate circuit to the signal input end of the target power domain circuit is the voltage of the reference ground of the target power domain circuit. In this way, the signal that is input to the signal input end of the target power domain circuit is at a logical low level in the target power domain circuit, thereby ensuring correct transmission of the logical level of the signal. 
     In addition, when the n power ends of the NAND gate circuit are all connected to the power supply of the target power domain circuit, and the ground end of the NAND gate circuit is connected to the reference ground of the power domain circuit to which the target signal output end of the n signal output ends belongs, if a signal transmitted by the target signal output end of the n signal output ends to the target input end of the n input ends of the NAND gate circuit is at a logical low level, the voltage of the target input end of the NAND gate circuit is equal to the voltage of the ground end of the NAND gate circuit. Therefore, provided that a voltage, after decreasing, of the power supply of the target power domain circuit is not smaller than the voltage of the power supply of each of the plurality of power domain circuits, the voltage of each of the n power ends of the NAND gate circuit is greater than the voltage of the ground end of the NAND gate circuit, and the voltage of the target input end of the NAND gate circuit is less than the turnover voltage of the NAND gate circuit. In this case, the voltage of the target input end of the NAND gate circuit is a voltage of a power end of the NAND gate circuit. In an embodiment, a voltage of a signal transmitted by the output end of the NAND gate circuit to the signal input end of the target power domain circuit is the voltage of the power supply of the target power domain circuit. In this way, the signal that is input to the signal input end of the target power domain circuit is at a logical high level in the target power domain circuit, thereby ensuring correct transmission of the logical level of the signal. 
     The NAND gate circuit includes n PMOS transistors and n NMOS transistors. 
     Both a gate of an i th  PMOS transistor of the n PMOS transistors and a gate of an i th  NMOS transistor of the n NMOS transistors are connected to the i th  signal output end. Both a drain of each of the n PMOS transistors and a drain of a first NMOS transistor of the n NMOS transistors are connected to the signal input end of the target power domain circuit. 
     A source of the i th  PMOS transistor is connected to the power supply of the power domain circuit to which the i th  signal output end belongs, the n NMOS transistors are connected in series, and a source of an n th  NMOS transistor of the n NMOS transistors is connected to the reference ground of the target power domain circuit. Alternatively, a source of each of the n PMOS transistors is connected to the power supply of the target power domain circuit, the n NMOS transistors are connected in series, and a source of the n th  NMOS transistor is connected to the reference ground of the power domain circuit to which the target signal output end belongs. 
     In this embodiment of the present disclosure, when the source of the i th  PMOS transistor is connected to the power supply of the power domain circuit to which the i th  signal output end belongs, the n NMOS transistors are connected in series, and the source of the n th  NMOS transistor of the n NMOS transistors is connected to the reference ground of the target power domain circuit, if signals transmitted by the n signal output ends to the n input ends of the NAND gate circuit are all at a logical high level, provided that a voltage, after increasing, of the reference ground of the target power domain circuit does not exceed the voltage of the power supply of each of the plurality of power domain circuits, the n PMOS transistors are all cut off, and the n NMOS transistors are all turned on. In this way, a voltage of a connection point between the drain of each of the n PMOS transistors and the drain of the first NMOS transistor is the voltage of the reference ground of the target power domain circuit connected to the source of the n th  NMOS transistor. In an embodiment, a voltage of a signal that is input to the signal input end of the target power domain circuit is the voltage of the reference ground of the target power domain circuit. 
     In addition, when the source of each of the n PMOS transistors is connected to the power supply of the target power domain circuit, the n NMOS transistors are connected in series, and the source of the n th  NMOS transistor is connected to the reference ground of the power domain circuit to which the target signal output end belongs, if a signal transmitted by the target signal output end of the n signal output ends to the target input end of the n input ends of the NAND gate circuit is at a logical low level, provided that a voltage, after decreasing, of the power supply of the target power domain circuit is not smaller than the voltage of the power supply of each of the plurality of power domain circuits, the n NMOS transistors are all cut off, and the n PMOS transistors are all turned on. In this way, the voltage of the connection point between the drain of each of the n PMOS transistors and the drain of the first NMOS transistor is the voltage of the power supply of the target power domain circuit connected to a source of a target PMOS transistor. In an embodiment, a voltage of a signal that is input to the signal input end of the target power domain circuit is the voltage of the power supply of the target power domain circuit. 
     According to a third aspect, an interface circuit is provided, including a NOR gate circuit. 
     There are m input ends of the NOR gate circuit respectively connected to m signal output ends of a plurality of power domain circuits, and an output end of the NOR gate circuit is connected to a signal input end of a target power domain circuit. The m input ends of the NOR gate circuit one-to-one correspond to m ground ends of the NOR gate circuit, and m is an integer greater than or equal to 2. 
     A power end of the NOR gate circuit is connected to a power supply of a power domain circuit to which a target signal output end of the m signal output ends belongs, the m ground ends of the NOR gate circuit are all connected to a reference ground of the target power domain circuit, and the target signal output end is connected to a target input end of the m input ends of the NOR gate circuit. Alternatively, a power end of the NOR gate circuit is connected to a power supply of the target power domain circuit, a k th  ground end of the m ground ends of the NOR gate circuit is connected to a reference ground of a power domain circuit to which a k th  signal output end of the m signal output ends belongs, and k is an integer greater than or equal to 1 and less than or equal to m. 
     Normally, a voltage of the power end of the NOR gate circuit is greater than a voltage of each of the m ground ends of the NOR gate circuit. In this case, if a voltage of the target input end of the NOR gate circuit is greater than a turnover voltage of the NOR gate circuit, a voltage of the output end of the NOR gate circuit is a voltage of a target ground end that is in the m ground ends of the NOR gate circuit and that corresponds to the target input end. If a voltage of each of the m input ends of the NOR gate circuit is less than the turnover voltage of the NOR gate circuit, the voltage of the output end of the NOR gate circuit is the voltage of the power end of the NOR gate circuit. The turnover voltage of the NOR gate circuit is a voltage between the voltage of the power end of the NOR gate circuit and a smallest voltage of voltages of the m ground ends of the NOR gate circuit. 
     It should be noted that the NOR gate circuit is configured for transition between logical states of a signal. Further, the NOR gate circuit is configured to, when any one of a plurality of input signals is at a logical high level, output a signal at a logical low level, or when a plurality of input signals are all at a logical low level, output a signal at a logical high level. 
     In this embodiment of the present disclosure, when the power end of the NOR gate circuit is connected to the power supply of the power domain circuit to which the target signal output end of the m signal output ends belongs, and the m ground ends of the NOR gate circuit are all connected to the reference ground of the target power domain circuit, if a signal transmitted by the target signal output end of the m signal output ends to the target input end of the m input ends of the NOR gate circuit is at a logical high level, the voltage of the target input end of the NOR gate circuit is equal to the voltage of the power end of the NOR gate circuit. Therefore, provided that a voltage, after increasing, of the reference ground of the target power domain circuit does not exceed the voltage of the power supply of each of the plurality of power domain circuits, the voltage of the power end of the NOR gate circuit is greater than the voltage of each of the m ground ends of the NOR gate circuit, and the voltage of the target input end of the NOR gate circuit is greater than the turnover voltage of the NOR gate circuit. In this case, the voltage of the output end of the NOR gate circuit is a voltage of a ground end of the NOR gate circuit. In an embodiment, a voltage of a signal transmitted by the output end of the NOR gate circuit to the signal input end of the target power domain circuit is the voltage of the reference ground of the target power domain circuit. In this way, the signal that is input to the signal input end of the target power domain circuit is at a logical low level in the target power domain circuit, thereby ensuring correct transmission of the logical level of the signal. 
     In addition, when the power end of the NOR gate circuit is connected to the power supply of the target power domain circuit, and the k th  ground end of the m ground ends of the NOR gate circuit is connected to the reference ground of the power domain circuit to which the k th  signal output end of the m signal output ends belongs, if signals transmitted by the m signal output ends to the m input ends of the NOR gate circuit are all at a logical low level, a voltage of a k th  input end of the NOR gate circuit is equal to a voltage of the k th  ground end of the NOR gate circuit. Therefore, provided that a voltage, after decreasing, of the power supply of the target power domain circuit is not smaller than the voltage of the reference ground of each of the plurality of power domain circuits, the voltage of the power end of the NOR gate circuit is greater than the voltage of each of the m ground ends of the NOR gate circuit, and the voltage of each of the m input ends of the NOR gate circuit is less than the turnover voltage of the NOR gate circuit. In this case, the voltage of the output end of the NOR gate circuit is the voltage of the power end of the NOR gate circuit. In an embodiment, a voltage of a signal transmitted by the output end of the NOR gate circuit to the signal input end of the target power domain circuit is the voltage of the power supply of the target power domain circuit. In this way, the signal that is input to the signal input end of the target power domain circuit is at a logical high level in the target power domain circuit, thereby ensuring correct transmission of the logical level of the signal. 
     The NOR gate circuit includes m PMOS transistors and m NMOS transistors. 
     Both a gate of a k th  PMOS transistor of the m PMOS transistors and a gate of a k th  NMOS transistor of the m NMOS transistors are connected to the k th  signal output end. Both a drain of an m th  PMOS transistor of the m PMOS transistors and a drain of each of the m NMOS transistors are connected to the signal input end of the target power domain circuit. 
     A source of a first PMOS transistor of the m PMOS transistors is connected to the power supply of the power domain circuit to which the target signal output end belongs, the m PMOS transistors are connected in series, and a source of each of the m NMOS transistors is connected to the reference ground of the target power domain circuit. Alternatively, a source of the first PMOS transistor is connected to the power supply of the target power domain circuit, the m PMOS transistors are connected in series, and a source of the k th  NMOS transistor is connected to the reference ground of the power domain circuit to which the k th  signal output end belongs. 
     In this embodiment of the present disclosure, when the source of the first PMOS transistor of the m PMOS transistors is connected to the power supply of the power domain circuit to which the target signal output end belongs, the m PMOS transistors are connected in series, and the source of each of the m NMOS transistors is connected to the reference ground of the target power domain circuit, if a signal transmitted by the target signal output end of the m signal output ends to the target input end of the m input ends of the NOR gate circuit is at a logical high level, provided that a voltage, after increasing, of the reference ground of the target power domain circuit does not exceed the voltage of the power supply of each of the plurality of power domain circuits, the m PMOS transistors are all cut off, and the m NMOS transistors are all turned on. In this way, a voltage of a connection point between the drain of the m th  PMOS transistor and the drain of each of the m NMOS transistors is the voltage of the reference ground of the target power domain circuit connected to a source of a target NMOS transistor. In an embodiment, a voltage of a signal that is input to the signal input end of the target power domain circuit is the voltage of the reference ground of the target power domain circuit. 
     In addition, when the source of the first PMOS transistor is connected to the power supply of the target power domain circuit, the m PMOS transistors are connected in series, and the source of the k th  NMOS transistor is connected to the reference ground of the power domain circuit to which the k th  signal output end belongs, if signals transmitted by the m signal output ends to the m input ends of the NOR gate circuit are all at a logical low level, provided that a voltage, after decreasing, of the power supply of the target power domain circuit is not smaller than the voltage of the reference ground of each of the plurality of power domain circuits, the m NMOS transistors are all cut off, and the m PMOS transistors are all turned on. In this way, the voltage of the connection point between the drain of the m th  PMOS transistor and the drain of each of the m NMOS transistors is the voltage of the reference ground of the target power domain circuit connected to a source of the M th  NMOS transistor. In an embodiment, a voltage of a signal that is input to the signal input end of the target power domain circuit is the voltage of the power supply of the target power domain circuit. 
     Beneficial effects brought by the technical solutions provided in this application are as follows. The input end of the phase inverter is connected to the signal output end of the first power domain circuit, and the output end of the phase inverter is connected to the signal input end of the second power domain circuit. In this case, if the power end of the phase inverter is connected to the power supply of the first power domain circuit, and the ground end of the phase inverter is connected to the reference ground of the second power domain circuit, when a signal transmitted by the signal output end of the first power domain circuit to the input end of the phase inverter is at a logical high level, the voltage of the input end of the phase inverter is equal to the voltage of the power end of the phase inverter. Therefore, even if the voltage of the reference ground of the second power domain circuit changes greatly due to electrostatic interference, provided that a voltage, after increasing, of the reference ground of the second power domain circuit does not exceed the voltage of the power supply of the first power domain circuit, the voltage of the power end of the phase inverter is greater than the voltage of the ground end of the phase inverter, and the voltage of the input end of the phase inverter is greater than the turnover voltage of the phase inverter. In this case, a voltage of a signal transmitted by the output end of the phase inverter to the signal input end of the second power domain circuit is the voltage of the reference ground of the second power domain circuit. In this way, the signal that is input to the signal input end of the second power domain circuit is at a logical low level in the second power domain circuit, thereby ensuring correct transmission of the logical level of the signal. If the power end of the phase inverter is connected to the power supply of the second power domain circuit, and the ground end of the phase inverter is connected to the reference ground of the first power domain circuit, when a signal transmitted by the signal output end of the first power domain circuit to the input end of the phase inverter is at a logical low level, the voltage of the input end of the phase inverter is equal to the voltage of the reference ground of the phase inverter. Therefore, even if the voltage of the power supply of the second power domain circuit changes greatly due to electrostatic interference, provided that a voltage, after decreasing, of the power supply of the second power domain circuit is not smaller than the voltage of the reference ground of the first power domain circuit, the voltage of the power end of the phase inverter is greater than the voltage of the ground end of the phase inverter, and the voltage of the input end of the phase inverter is less than the turnover voltage of the phase inverter. In this case, a voltage of a signal transmitted by the output end of the phase inverter to the signal input end of the second power domain circuit is the voltage of the power supply of the second power domain circuit. In this way, the signal that is input to the signal input end of the second power domain circuit is at a logical high level in the second power domain circuit, thereby ensuring correct transmission of the logical level of the signal. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a schematic diagram of a power domain circuit interfered with by positive static electricity according to an embodiment of the present disclosure. 
         FIG. 1B  is a schematic diagram of a power domain circuit interfered with by negative static electricity according to an embodiment of the present disclosure. 
         FIG. 1C  is a schematic diagram of voltage increases of a power supply and a reference ground according to an embodiment of the present disclosure. 
         FIG. 1D  is a schematic diagram of voltage decreases of a power supply and a reference ground according to an embodiment of the present disclosure. 
         FIG. 2A  is a schematic structural diagram of a first interface circuit according to an embodiment of the present disclosure. 
         FIG. 2B  is a schematic structural diagram of a second interface circuit according to an embodiment of the present disclosure. 
         FIG. 2C  is a schematic structural diagram of a third interface circuit according to an embodiment of the present disclosure. 
         FIG. 2D  is a schematic structural diagram of a fourth interface circuit according to an embodiment of the present disclosure. 
         FIG. 3A  is a schematic structural diagram of a fifth interface circuit according to an embodiment of the present disclosure. 
         FIG. 3B  is a schematic structural diagram of a sixth interface circuit according to an embodiment of the present disclosure. 
         FIG. 3C  is a schematic structural diagram of a seventh interface circuit according to an embodiment of the present disclosure. 
         FIG. 3D  is a schematic structural diagram of an eighth interface circuit according to an embodiment of the present disclosure. 
         FIG. 4A  is a schematic structural diagram of a ninth interface circuit according to an embodiment of the present disclosure. 
         FIG. 4B  is a schematic structural diagram of a tenth interface circuit according to an embodiment of the present disclosure. 
         FIG. 4C  is a schematic structural diagram of an eleventh interface circuit according to an embodiment of the present disclosure. 
         FIG. 4D  is a schematic structural diagram of a twelfth interface circuit according to an embodiment of the present disclosure. 
       Reference numerals.  1  is a phase inverter,  1   a  is an input end of the phase inverter,  1   b  is an output end of the phase inverter,  1   c  is a power end of the phase inverter,  1   d  is a ground end of the phase inverter,  2  is a first power domain circuit,  2   a  is a signal output end of the first power domain circuit, vdd 1  is a power supply of the first power domain circuit, vss 1  is a reference ground of the first power domain circuit,  3  is a second power domain circuit,  3   a  is a signal input end of the second power domain circuit, vdd 2  is a power supply of the second power domain circuit, vss 2  is a reference ground of the second power domain circuit,  4  is a NAND gate circuit,  4   a  is an input end of the NAND gate circuit,  4   a   t  is a target input end of the NAND gate circuit,  4   b  is an output end of the NAND gate circuit,  4   c  is a power end of the NAND gate circuit,  4   c   t  is a target power end of the NAND gate circuit,  4   d  is a ground end of the NAND gate circuit,  5  is a power domain circuit,  5   a  is a signal output end of the power domain circuit,  5   a   t  is a target signal output end of the power domain circuit,  6  is a target power domain circuit,  6   a  is a signal input end of the target power domain circuit,  7  is a NOR gate circuit,  7   a  is an input end of the NOR gate circuit,  7   a   t  is a target input end of the NOR gate circuit,  7   b  is an output end of the NOR gate circuit,  7   c  is a power end of the NOR gate circuit,  7   d  is a ground end of the NOR gate circuit,  7   d   t  is a target ground end of the NOR gate circuit, Q 1  is a PMOS transistor, g 1  is a gate of the PMOS transistor, s 1  is a source of the PMOS transistor, d 1  is a drain of the PMOS transistor, Q 1   t  is a target PMOS transistor, g 1   t  is a gate of the target PMOS transistor, s 1   t  is a source of the target PMOS transistor, d 1   t  is a drain of the target PMOS transistor, Q 2  is a NMOS transistor, g 2  is a gate of the NMOS transistor, s 2  is a source of the NMOS transistor, d 2  is a drain of the NMOS, Q 2   t  is a target NMOS transistor, g 2   t  is a gate of the target NMOS transistor, s 2   t  is a source of the target NMOS transistor, d 2   t  is a drain of the target NMOS transistor. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     To make the objectives, technical solutions, and advantages of this application clearer, the following further describes the implementations of this application in detail with reference to the accompanying drawings. 
     Before the embodiments of the present disclosure are described in detail, an application scenario of the embodiments of the present disclosure is described. 
     Currently, a signal cable, a power cable, a ground cable, and the like in a chip are prone to electrostatic interference in a plugging or unplugging process or in a normal working process. A voltage of a power supply and a voltage of a reference ground of each power domain circuit in the chip change greatly due to the electrostatic interference. For example, the chip includes a power domain circuit in which a digital circuit is located and a power domain circuit in which an analog circuit is located. It is assumed that a signal cable in the power domain circuit in which the analog circuit is located is interfered with by positive static electricity. As shown in  FIG. 1A , the static electricity is transmitted to a reference ground AVSS of the power domain circuit using a diode DIOP and an ESD clamp circuit. Consequently, a voltage of the reference ground AVSS increases. Because there are a comparatively large quantity of capacitors between a power supply AVDD of the power domain circuit and the reference ground AVSS, a voltage of the power supply AVDD increases with the voltage of the reference ground AVSS. It is also assumed that a signal cable in the power domain circuit in which the analog circuit is located is interfered with by negative static electricity. As shown in  FIG. 1B , the static electricity is transmitted to the reference ground AVSS using a diode DION. Consequently, the voltage of the reference ground AVSS decreases. When the voltage of the reference ground AVSS decreases, the voltage of the power supply AVDD decreases with the voltage of the reference ground AVSS. 
     In this case, compared with a voltage of a power supply DVDD and a voltage of a reference ground DVSS of the power domain circuit in which the digital circuit is located, a turnover voltage of the power domain circuit in which the analog circuit is located changes more dramatically. For example, when the power domain circuit in which the analog circuit is located is interfered with by the positive static electricity in  FIG. 1A , as shown in  FIG. 1C , the voltage of the power supply AVDD may increase to a point A′ instantaneously from a point A, and the voltage of the reference ground AVSS may increase to a point B′ instantaneously from a point B. Consequently, the turnover voltage of the power domain circuit in which the analog circuit is located increases and exceeds the voltage of the power supply DVDD. For another example, when the power domain circuit in which the analog circuit is located is interfered with by the negative static electricity in  FIG. 1B , as shown in  FIG. 1D , the voltage of the power supply AVDD may decrease to a point A″ instantaneously from the point A, and the voltage of the reference ground AVSS may decrease to a point B″ instantaneously from the point B. Consequently, the turnover voltage of the power domain circuit in which the analog circuit is located decreases and is smaller than the voltage of the reference ground DVSS. 
     The increase or the decrease of the turnover voltage of the power domain circuit in which the analog circuit is located is very likely to cause an error to a logical level of a signal transmitted by the power domain circuit in which the digital circuit is located to the power domain circuit in which the analog circuit is located. For example, the signal transmitted by the power domain circuit in which the digital circuit is located to the power domain circuit in which the analog circuit is located is at a logical high level. In an embodiment, a voltage of the signal is the voltage of the power supply DVDD. In this case, if the turnover voltage of the power domain circuit in which the analog circuit is located increases and exceeds the voltage of the power supply DVDD due to the interference of the positive static electricity, the signal is incorrectly considered to be at a logical low level in the power domain circuit in which the analog circuit is located. For another example, the signal transmitted by the power domain circuit in which the digital circuit is located to the power domain circuit in which the analog circuit is located is at a logical low level. In an embodiment, a voltage of the signal is the voltage of the reference ground DVSS. In this case, if the turnover voltage of the power domain circuit in which the analog circuit is located decreases and is smaller than the voltage of the reference ground DVSS due to the interference of the negative static electricity, the signal is incorrectly considered to be at a logical high level in the power domain circuit in which the analog circuit is located. 
     It can be learned from the foregoing that when a signal transmitted by a power domain circuit to another power domain circuit that is interfered with by positive static electricity is at a logical high level, the logical level of the signal is very likely to be incorrectly transmitted at a logical low level, and when a signal transmitted by a power domain circuit to another power domain circuit that is interfered with by negative static electricity is at a logical low level, the logical level of the signal is very likely to be incorrectly transmitted at a logical high level. Incorrect transmission of a logical level of a signal is very likely to cause an incorrect change in internal state logic or a state of some registers in a power domain circuit receiving the signal. This causes an error to a data transmission link between power domain circuits in a chip, and affects working performance of the chip. Therefore, the embodiments of the present disclosure provide three interface circuits, to correctly transmit a logical level of a signal, thereby ensuring stability and reliability of a data transmission link between power domain circuits in a chip, and improving working performance of the chip. 
     It should be noted that voltages in the embodiments of the present disclosure are all determined based on a chip ground of a chip. For example, a voltage of a power supply of a power domain circuit is a potential difference between the power supply of the power domain circuit and a chip ground of a chip in which the power domain circuit is located, and a voltage of a reference ground of a power domain circuit is a potential difference between the reference ground of the power domain circuit and a chip ground of a chip in which the power domain circuit is located. Concepts of other voltages in the embodiments of the present disclosure are similar thereto, and details are not described herein. 
     The following describes in detail a first interface circuit provided in an embodiment of the present disclosure. 
       FIG. 2A  and  FIG. 2B  are schematic structural diagrams of an interface circuit according to an embodiment of the present disclosure. Referring to  FIG. 2A  and  FIG. 2B , the interface circuit includes a phase inverter  1 . 
     An input end  1   a  of the phase inverter  1  is connected to a signal output end  2   a  of a first power domain circuit  2 , and an output end  1   b  of the phase inverter  1  is connected to a signal input end  3   a  of a second power domain circuit  3 . 
     Referring to  FIG. 2A , a power end  1   c  of the phase inverter  1  is connected to a power supply vdd 1  of the first power domain circuit  2 , and a ground end  1   d  of the phase inverter  1  is connected to a reference ground vss 2  of the second power domain circuit  3 . Alternatively, referring to  FIG. 2B , a power end  1   c  of the phase inverter  1  is connected to a power supply vdd 2  of the second power domain circuit  3 , and a ground end  1   d  of the phase inverter  1  is connected to a reference ground vss 1  of the first power domain circuit  2 . 
     Normally, a voltage of the power end  1   c  of the phase inverter  1  is greater than a voltage of the ground end  1   d  of the phase inverter  1 . In this case, if a voltage of the input end  1   a  of the phase inverter  1  is greater than a turnover voltage of the phase inverter  1 , a voltage of the output end  1   b  of the phase inverter  1  is the voltage of the ground end  1   d  of the phase inverter  1 . If a voltage of the input end  1   a  of the phase inverter  1  is less than a turnover voltage of the phase inverter  1 , a voltage of the output end  1   b  of the phase inverter  1  is the voltage of the power end  1   c  of the phase inverter  1 . 
     It should be noted that the phase inverter  1  is configured for transition between logical states of a signal. Further, the phase inverter  1  is configured to, when an input signal is at a logical high level (that is, in a logical state “1”), output a signal at a logical low level (that is, in a logical state “0”), or when an input signal is at a logical low level, output a signal at a logical high level. 
     In addition, the turnover voltage of the phase inverter  1  is less than a first voltage of the phase inverter  1  and is greater than a second voltage of the phase inverter  1 . The first voltage of the phase inverter  1  is a larger voltage of the voltage of the power end  1   c  of the phase inverter  1  and the voltage of the ground end  1   d  of the phase inverter  1 . The second voltage of the phase inverter  1  is a smaller voltage of the voltage of the power end  1   c  of the phase inverter  1  and the voltage of the ground end  1   d  of the phase inverter  1 . For example, the turnover voltage of the phase inverter  1  may be half of a sum of the voltage of the power end  1   c  of the phase inverter  1  and the voltage of the ground end  1   d  of the phase inverter  1 . 
     It should be noted that the first power domain circuit  2  and the second power domain circuit  3  may be two different power domain circuits. In an embodiment, the first power domain circuit  2  and the second power domain circuit  3  use power supply solutions independent of each other, or in other words, a power supply circuit of the first power domain circuit  2  is different from a power supply circuit of the second power domain circuit  3 . 
     In addition, for a power domain circuit, a voltage of a signal that is output by the power domain circuit at a logical high level is a voltage of a power supply of the power domain circuit, and a voltage of a signal that is output by the power domain circuit at a logical low level is a voltage of a reference ground of the power domain circuit. For example, if a signal that is output by the first power domain circuit  2  is at a logical high level, a voltage of the signal is a voltage of the power supply vdd 1  of the first power domain circuit  2 . For another example, if a signal that is output by the first power domain circuit  2  is at a logical low level, a voltage of the signal is a voltage of the reference ground vss 1  of the first power domain circuit  2 . 
     It should be noted that when the power end  1   c  of the phase inverter  1  is connected to the power supply vdd 1  of the first power domain circuit  2 , and the ground end  1   d  of the phase inverter  1  is connected to the reference ground vss 2  of the second power domain circuit  3 , the voltage of the power end  1   c  of the phase inverter  1  is the voltage of the power supply vdd 1  of the first power domain circuit  2 , and the voltage of the ground end  1   d  of the phase inverter  1  is a voltage of the reference ground vss 2  of the second power domain circuit  3 . In this case, when a signal transmitted by the signal output end  2   a  of the first power domain circuit  2  to the input end  1   a  of the phase inverter  1  is at a logical high level, the voltage of the input end  1   a  of the phase inverter  1  is the voltage of the power supply vdd 1  of the first power domain circuit  2 . In other words, the voltage of the input end  1   a  of the phase inverter  1  is equal to the voltage of the power end  1   c  of the phase inverter  1 . Therefore, even if the voltage of the reference ground vss 2  of the second power domain circuit  3  changes greatly due to electrostatic interference, provided that a voltage, after increasing, of the reference ground vss 2  of the second power domain circuit  3  does not exceed the voltage of the power supply vdd 1  of the first power domain circuit  2 , the voltage of the power end  1   c  of the phase inverter  1  is greater than the voltage of the ground end  1   d  of the phase inverter  1 , and the voltage of the input end  1   a  of the phase inverter  1  is greater than the turnover voltage of the phase inverter  1 . In this case, the voltage of the output end  1   b  of the phase inverter  1  is the voltage of the ground end  1   d  of the phase inverter  1 . In an embodiment, a voltage of a signal transmitted by the output end  1   b  of the phase inverter  1  to the signal input end  3   a  of the second power domain circuit  3  is the voltage of the reference ground vss 2  of the second power domain circuit  3 . 
     When the voltage of the signal transmitted by the output end  1   b  of the phase inverter  1  to the signal input end  3   a  of the second power domain circuit  3  is the voltage of the reference ground vss 2  of the second power domain circuit  3 , the signal that is input to the signal input end  3   a  of the second power domain circuit  3  is at a logical low level in the second power domain circuit  3 . In this case, a signal that is input by the first power domain circuit  2  to the phase inverter  1  is at a logical high level, and then a signal that is input by the phase inverter  1  to the second power domain circuit  3  is at a logical low level such that the logical level of the signal is correctly transmitted, thereby ensuring stability and reliability of a data transmission link between the first power domain circuit  2  and the second power domain circuit  3 , enhancing an electrostatic interference resistance capability of a chip provided with the interface circuit, and improving working performance of the chip. 
     In addition, when the power end  1   c  of the phase inverter  1  is connected to the power supply vdd 2  of the second power domain circuit  3 , and the ground end  1   d  of the phase inverter  1  is connected to the reference ground vss 1  of the first power domain circuit  2 , the voltage of the power end  1   c  of the phase inverter  1  is the voltage of the power supply vdd 2  of the second power domain circuit  3 , and the voltage of the ground end  1   d  of the phase inverter  1  is the voltage of the reference ground vss 1  of the first power domain circuit  2 . In this case, when a signal transmitted by the signal output end  2   a  of the first power domain circuit  2  to the input end  1   a  of the phase inverter  1  is at a logical low level, the voltage of the input end  1   a  of the phase inverter  1  is the voltage of the reference ground vss 1  of the first power domain circuit  2 . In other words, the voltage of the input end  1   a  of the phase inverter  1  is equal to the voltage of the ground end  1   d  of the phase inverter  1 . Therefore, even if the voltage of the power supply vdd 2  of the second power domain circuit  3  changes greatly due to electrostatic interference, provided that a voltage, after decreasing, of the power supply vdd 2  of the second power domain circuit  3  is not smaller than the voltage of the reference ground vss 1  of the first power domain circuit  2 , the voltage of the power end  1   c  of the phase inverter  1  is greater than the voltage of the ground end  1   d  of the phase inverter  1 , and the voltage of the input end  1   a  of the phase inverter  1  is less than the turnover voltage of the phase inverter  1 . In this case, the voltage of the output end  1   b  of the phase inverter  1  is the voltage of the power end  1   c  of the phase inverter  1 . In an embodiment, a voltage of a signal transmitted by the output end  1   b  of the phase inverter  1  to the signal input end  3   a  of the second power domain circuit  3  is the voltage of the power supply vdd 2  of the second power domain circuit  3 . 
     When the voltage of the signal transmitted by the output end  1   b  of the phase inverter  1  to the signal input end  3   a  of the second power domain circuit  3  is the voltage of the power supply vdd 2  of the second power domain circuit  3 , the signal that is input to the signal input end  3   a  of the second power domain circuit  3  is at a logical high level in the second power domain circuit  3 . In this case, a signal that is input by the first power domain circuit  2  to the phase inverter  1  is at a logical low level, and then a signal that is input by the phase inverter  1  to the second power domain circuit  3  is at a logical high level such that the logical level of the signal is correctly transmitted, thereby ensuring stability and reliability of a data transmission link between the first power domain circuit  2  and the second power domain circuit  3 , enhancing an electrostatic interference resistance capability of a chip provided with the interface circuit, and improving working performance of the chip. 
     Referring to  FIG. 2C  and  FIG. 2D , the phase inverter  1  includes a PMOS transistor Q 1  and an NMOS transistor Q 2 . 
     Both a gate g 1  of the PMOS transistor Q 1  and a gate g 2  of the NMOS transistor Q 2  are connected to the signal output end  2   a  of the first power domain circuit  2 . Both a drain dl of the PMOS transistor Q 1  and a drain d 2  of the NMOS transistor Q 2  are connected to the signal input end  3   a  of the second power domain circuit  3 . 
     Referring to  FIG. 2C , a source s 1  of the PMOS transistor Q 1  is connected to the power supply vdd 1  of the first power domain circuit  2 , and a source s 2  of the NMOS transistor Q 2  is connected to the reference ground vss 2  of the second power domain circuit  3 . Alternatively, referring to  FIG. 2D , a source s 1  of the PMOS transistor Q 1  is connected to the power supply vdd 2  of the second power domain circuit  3 , and a source s 2  of the NMOS transistor Q 2  is connected to the reference ground vss 1  of the first power domain circuit  2 . 
     It should be noted that when the source s 1  of the PMOS transistor Q 1  is connected to the power supply vdd 1  of the first power domain circuit  2 , and the source s 2  of the NMOS transistor Q 2  is connected to the reference ground vss 2  of the second power domain circuit  3 , if a signal transmitted by the signal output end  2   a  of the first power domain circuit  2  to the input end  1   a  of the phase inverter  1  is at a logical high level, voltages applied to the gate g 1  of the PMOS transistor Q 1  and the gate g 2  of the NMOS transistor Q 2  are the voltage of the power supply vdd 1  of the first power domain circuit  2 . In this case, the voltage of the gate g 1  of the PMOS transistor Q 1  is equal to a voltage of the source s 1  of the PMOS transistor Q 1 , and the PMOS transistor Q 1  is cut off. When a voltage, after increasing, of the reference ground vss 2  of the second power domain circuit  3  does not exceed the voltage of the power supply vdd 1  of the first power domain circuit  2 , the voltage of the gate g 2  of the NMOS transistor Q 2  is greater than a voltage of the source s 2  of the NMOS transistor Q 2 , and the NMOS transistor Q 2  is turned on. In this way, a voltage of a connection point between the drain d 1  of the PMOS transistor Q 1  and the drain d 2  of the NMOS transistor Q 2  is the voltage of the reference ground vss 2  of the second power domain circuit  3  connected to the source s 2  of the NMOS transistor Q 2 . In an embodiment, a voltage of a signal that is input to the signal input end  3   a  of the second power domain circuit  3  is the voltage of the reference ground vss 2  of the second power domain circuit 
     In addition, when the source s 1  of the PMOS transistor Q 1  is connected to the power supply vdd 2  of the second power domain circuit  3 , and the source s 2  of the NMOS transistor Q 2  is connected to the reference ground vss 1  of the first power domain circuit  2 , if a signal transmitted by the signal output end  2   a  of the first power domain circuit  2  to the input end  1   a  of the phase inverter  1  is at a logical low level, voltages applied to the gate g 1  of the PMOS transistor Q 1  and the gate g 2  of the NMOS transistor Q 2  are the voltage of the reference ground vss 1  of the first power domain circuit  2 . In this case, the voltage of the gate g 2  of the NMOS transistor Q 2  is equal to the voltage of the source s 2  of the NMOS transistor Q 2 , and the NMOS transistor Q 2  is cut off. When a voltage, after decreasing, of the power supply vdd 2  of the second power domain circuit  3  is not smaller than the voltage of the reference ground vss 1  of the first power domain circuit  2 , the voltage of the gate g 1  of the PMOS transistor Q 1  is less than the voltage of the source s 1  of the PMOS transistor Q 1 , and the PMOS transistor Q 1  is turned on. In this way, the voltage of the connection point between the drain dl of the PMOS transistor Q 1  and the drain d 2  of the NMOS transistor Q 2  is the voltage of the power supply vdd 2  of the second power domain circuit  3  connected to the source s 1  of the PMOS transistor Q 1 . In an embodiment, a voltage of a signal that is input to the signal input end  3   a  of the second power domain circuit  3  is the voltage of the power supply vdd 2  of the second power domain circuit  3 . 
     In this embodiment of the present disclosure, the input end of the phase inverter is connected to the signal output end of the first power domain circuit, and the output end of the phase inverter is connected to the signal input end of the second power domain circuit. In this case, if the power end of the phase inverter is connected to the power supply of the first power domain circuit, and the ground end of the phase inverter is connected to the reference ground of the second power domain circuit, when a signal transmitted by the signal output end of the first power domain circuit to the input end of the phase inverter is at a logical high level, the voltage of the input end of the phase inverter is equal to the voltage of the power end of the phase inverter. Therefore, even if the voltage of the reference ground of the second power domain circuit changes greatly due to electrostatic interference, provided that a voltage, after increasing, of the reference ground of the second power domain circuit does not exceed the voltage of the power supply of the first power domain circuit, the voltage of the power end of the phase inverter is greater than the voltage of the ground end of the phase inverter, and the voltage of the input end of the phase inverter is greater than the turnover voltage of the phase inverter. In this case, a voltage of a signal transmitted by the output end of the phase inverter to the signal input end of the second power domain circuit is the voltage of the reference ground of the second power domain circuit. In this way, the signal that is input to the signal input end of the second power domain circuit is at a logical low level in the second power domain circuit, thereby ensuring correct transmission of the logical level of the signal. If the power end of the phase inverter is connected to the power supply of the second power domain circuit, and the ground end of the phase inverter is connected to the reference ground of the first power domain circuit, when a signal transmitted by the signal output end of the first power domain circuit to the input end of the phase inverter is at a logical low level, the voltage of the input end of the phase inverter is equal to the voltage of the reference ground of the phase inverter. Therefore, even if the voltage of the power supply of the second power domain circuit changes greatly due to electrostatic interference, provided that a voltage, after decreasing, of the power supply of the second power domain circuit is not smaller than the voltage of the reference ground of the first power domain circuit, the voltage of the power end of the phase inverter is greater than the voltage of the ground end of the phase inverter, and the voltage of the input end of the phase inverter is less than the turnover voltage of the phase inverter. In this case, a voltage of a signal transmitted by the output end of the phase inverter to the signal input end of the second power domain circuit is the voltage of the power supply of the second power domain circuit. In this way, the signal that is input to the signal input end of the second power domain circuit is at a logical high level in the second power domain circuit, thereby ensuring correct transmission of the logical level of the signal. 
     The following describes in detail a second interface circuit provided in an embodiment of the present disclosure. 
       FIG. 3A  and  FIG. 3B  are schematic structural diagrams of an interface circuit according to an embodiment of the present disclosure. Referring to  FIG. 3A  and  FIG. 3B , the interface circuit includes a NAND gate circuit  4 . 
     n input ends  4   a  of the NAND gate circuit  4  are respectively connected to n signal output ends  5   a  of a plurality of power domain circuits  5 , and an output end  4   b  of the NAND gate circuit  4  is connected to a signal input end  6   a  of a target power domain circuit  6 . The n input ends  4   a  of the NAND gate circuit  4  one-to-one correspond to n power ends  4   c  of the NAND gate circuit  4 , and n is an integer greater than or equal to 2. 
     Referring to  FIG. 3A , an i th  power end  4   c   i  of the n power ends  4   c  of the NAND gate circuit  4  is connected to a power supply of a power domain circuit to which an i th  signal output end  5   a,  of the n signal output ends  5   a  belongs, a ground end  4   d  of the NAND gate circuit  4  is connected to a reference ground of the target power domain circuit  6 , and i is an integer greater than or equal to 1 and less than or equal to n. Alternatively, referring to  FIG. 3B , the n power ends  4   c  of the NAND gate circuit  4  are all connected to a power supply of the target power domain circuit  6 , and a ground end  4   d  of the NAND gate circuit  4  is connected to a reference ground of a power domain circuit to which a target signal output end  5   a   t  of the n signal output ends  5   a  belongs, and the target signal output end  5   a   t  is connected to a target input end  4   a   t  of the n input ends  4   a  of the NAND gate circuit  4 . 
     Normally, a voltage of each of the n power ends  4   c  of the NAND gate circuit  4  is greater than a voltage of the ground end  4   d  of the NAND gate circuit  4 . In this case, if a voltage of each of the n input ends  4   a  of the NAND gate circuit  4  is greater than a turnover voltage of the NAND gate circuit  4 , a voltage of the output end  4   b  of the NAND gate circuit  4  is the voltage of the ground end  4   d  of the NAND gate circuit  4 . If a voltage of the target input end  4   a   t  of the NAND gate circuit  4  is less than the turnover voltage of the NAND gate circuit  4 , the voltage of the output end  4   b  of the NAND gate circuit  4  is a voltage of a target power end  4   c   t  that is in the n power ends  4   c  of the NAND gate circuit  4  and that corresponds to the target input end  4   a   t . 
     It should be noted that the NAND gate circuit  4  is configured for transition between logical states of a signal. Further, the NAND gate circuit  4  is configured to, when a plurality of input signals are all at a logical high level, output a signal at a logical low level, or when any one of a plurality of input signals is at a logical low level, output a signal at a logical high level. 
     In addition, the turnover voltage of the NAND gate circuit  4  is less than a first voltage of the NAND gate circuit  4  and is greater than a second voltage of the NAND gate circuit  4 . The first voltage of the NAND gate circuit  4  is a larger voltage of the voltage of the ground end  4   d  of the NAND gate circuit  4  and a smallest voltage of voltages of the n power ends  4   c  of the NAND gate circuit  4 . The second voltage of the NAND gate circuit  4  is a smaller voltage of the voltage of the ground end  4   d  of the NAND gate circuit  4  and the smallest voltage of the voltages of the n power ends  4   c  of the NAND gate circuit  4 . For example, the turnover voltage of the NAND gate circuit  4  may be half of a sum of the voltage of the ground end  4   d  of the NAND gate circuit  4  and the smallest voltage of the voltages of the n power ends  4   c  of the NAND gate circuit  4 . 
     It should be noted that the plurality of power domain circuits  5  and the target power domain circuit  6  may be different power domain circuits. In an embodiment, the plurality of power domain circuits  5  and the target power domain circuit  6  use power supply solutions independent of each other, or in other words, power supply circuits of the plurality of power domain circuits  5  are different from a power supply circuit of the target power domain circuit  6 . Each of the plurality of power domain circuits  5  may have at least one signal output end, and the plurality of power domain circuits  5  may have the n signal output ends in total. 
     In addition, for a power domain circuit, a voltage of a signal that is output by the power domain circuit at a logical high level is a voltage of a power supply of the power domain circuit, and a voltage of a signal that is output by the power domain circuit at a logical low level is a voltage of a reference ground of the power domain circuit. For example, if a signal that is output by any one of the plurality of power domain circuits  5  is at a logical high level, a voltage of the signal is a voltage of a power supply of the power domain circuit. For another example, if a signal that is output by any one of the plurality of power domain circuits  5  is at a logical low level, a voltage of the signal is a voltage of a reference ground of the power domain circuit. 
     It should be noted that when the i th  power end  4   c,  of the n power ends  4   c  of the NAND gate circuit  4  is connected to the power supply of the power domain circuit to which the i th  signal output end  5   a,  of the n signal output ends  5   a  belongs, and the ground end  4   d  of the NAND gate circuit  4  is connected to the reference ground of the target power domain circuit  6 , a voltage of the i th  power end  4   c,  of the NAND gate circuit  4  is a voltage of the power supply of the power domain circuit to which the i th  signal output end  5   a,  belongs, and the voltage of the ground end  4   d  of the NAND gate circuit  4  is a voltage of the reference ground of the target power domain circuit  6 . In this case, when signals transmitted by the n signal output ends  5   a  to the n input ends  4   a  of the NAND gate circuit  4  are all at a logical high level, a voltage of an i th  input end  4   a,  of the n input ends  4   a  of the NAND gate circuit  4  is the voltage of the power supply of the power domain circuit to which the i th  signal output end  5   a,  belongs. In other words, the voltage of the i th  input end  4   a,  of the NAND gate circuit  4  is equal to the voltage of the i th  power end  4   c,  of the NAND gate circuit  4 . Therefore, even if the voltage of the reference ground of the target power domain circuit  6  changes greatly due to electrostatic interference, provided that a voltage, after increasing, of the reference ground of the target power domain circuit  6  does not exceed a voltage of a power supply of each of the plurality of power domain circuits  5 , a voltage of each of the n power ends  4   c  of the NAND gate circuit  4  is greater than the voltage of the ground end  4   d  of the NAND gate circuit  4 , and a voltage of each of the n input ends  4   a  of the NAND gate circuit  4  is greater than the turnover voltage of the NAND gate circuit  4 . In this case, the voltage of the output end  4   b  of the NAND gate circuit  4  is the voltage of the ground end  4   d  of the NAND gate circuit  4 . In an embodiment, a voltage of a signal transmitted by the output end  4   b  of the NAND gate circuit  4  to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the reference ground of the target power domain circuit  6 . 
     When the voltage of the signal transmitted by the output end  4   b  of the NAND gate circuit  4  to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the reference ground of the target power domain circuit  6 , the signal that is input to the signal input end  6   a  of the target power domain circuit  6  is at a logical low level in the target power domain circuit  6 . In this case, signals that are input by the plurality of power domain circuits  5  to the NAND gate circuit  4  are all at a logical high level, and then a signal that is input by the NAND gate circuit  4  to the target power domain circuit  6  is at a logical low level such that the logical level of the signal is correctly transmitted, thereby ensuring stability and reliability of data transmission links between the target power domain circuit  6  and the plurality of power domain circuits  5 , enhancing an electrostatic interference resistance capability of a chip provided with the interface circuit, and improving working performance of the chip. 
     In addition, when the n power ends  4   c  of the NAND gate circuit  4  are all connected to the power supply of the target power domain circuit  6 , and the ground end  4   d  of the NAND gate circuit  4  is connected to the reference ground of the power domain circuit to which the target signal output end  5   a   t  of the n signal output ends  5   a  belongs, the voltages of the n power ends  4   c  of the NAND gate circuit  4  are all the voltage of the power supply of the target power domain circuit  6 , and the voltage of the ground end  4   d  of the NAND gate circuit  4  is a voltage of the reference ground of the power domain circuit to which the target signal output end  5   a   t  belongs. In this case, when a signal transmitted by the target signal output end  5   a   t  of the n signal output ends  5   a  to the target input end  4   a   t  of the n input ends  4   a  of the NAND gate circuit  4  is at a logical low level, the voltage of the target input end  4   a   t  of the NAND gate circuit  4  is the voltage of the reference ground of the power domain circuit to which the target signal output end  5   a   t  belongs. In other words, the voltage of the target input end  4   a   t  of the NAND gate circuit  4  is equal to the voltage of the ground end  4   d  of the NAND gate circuit  4 . Therefore, even if the voltage of the power supply of the target power domain circuit  6  changes greatly due to electrostatic interference, provided that a voltage, after decreasing, of the power supply of the target power domain circuit  6  is not smaller than the voltage of the power supply of each of the plurality of power domain circuits  5 , the voltage of each of the n power ends  4   c  of the NAND gate circuit  4  is greater than the voltage of the ground end  4   d  of the NAND gate circuit  4 , and the voltage of the target input ends  4   a   t  of the NAND gate circuit  4  is smaller than the turnover voltage of the NAND gate circuit  4 . In this case, the voltage of the output end  4   b  of the NAND gate circuit  4  is the voltage of the target power end  4   c   t  that is in the n power ends  4   c  of the NAND gate circuit  4  and that corresponds to the target input end  4   a   t . In an embodiment, a voltage of a signal transmitted by the output end  4   b  of the NAND gate circuit  4  to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the power supply of the target power domain circuit  6 . 
     When the voltage of the signal transmitted by the output end  4   b  of the NAND gate circuit  4  to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the power supply of the target power domain circuit  6 , the signal that is input to the signal input end  6   a  of the target power domain circuit  6  is at a logical high level in the target power domain circuit  6 . In this case, at least one of signals that are input by the plurality of power domain circuits  5  to the NAND gate circuit  4  is at a logical low level, and then a signal that is input by the NAND gate circuit  4  to the target power domain circuit  6  is at a logical high level such that the logical level of the signal is correctly transmitted, thereby ensuring stability and reliability of data transmission links between the target power domain circuit  6  and the plurality of power domain circuits  5 , enhancing an electrostatic interference resistance capability of a chip provided with the interface circuit, and improving working performance of the chip. 
     Referring to  FIG. 3C  and  FIG. 3D , the NAND gate circuit  4  includes n PMOS transistors Q 1  and n NMOS transistors Q 2 . 
     Both a gate g 1   1  of an i th  PMOS transistor Q 1   i  of the n PMOS transistors Q 1  and a gate g 2   i  of an i th  NMOS transistor Q 2   i  of the n NMOS transistors Q 2  are connected to the i th  signal output end  5   a   i . Both a drain d 1  of each of the n PMOS transistors Q 1  and a drain d 2   1  of a first NMOS transistor Q 2   1  of the n NMOS transistors Q 2  are connected to the signal input end  6   a  of the target power domain circuit  6 . 
     Referring to  FIG. 3C , a source s 1   i  of the i th  PMOS transistor Q 1   i  is connected to the power supply of the power domain circuit to which the i th  signal output end  5   a   i  belongs, the n NMOS transistors Q 2  are connected in series, and a source s 2   n  of an n th  NMOS transistor Q 2   n  of the n NMOS transistors Q 2  is connected to the reference ground of the target power domain circuit  6 . Alternatively, referring to  FIG. 3D , a source s 1  of each of the n PMOS transistors Q 1  is connected to the power supply of the target power domain circuit  6 , the n NMOS transistors Q 2  are connected in series, and a source s 2   n  of an n th  NMOS transistor Q 2   n  is connected to the reference ground of the power domain circuit to which the target signal output end  5   a   t  belongs. 
     It should be noted that when the source s 1   i  of the i th  PMOS transistor Q 1   i  is connected to the power supply of the power domain circuit to which the i th  signal output end  5   a,  belongs, the n NMOS transistors Q 2  are connected in series, and the source s 2   n  of the n th  NMOS transistor Q 2   n  of the n NMOS transistors Q 2  is connected to the reference ground of the target power domain circuit  6 , if a signal transmitted by the i th  signal output end  5   a   i  to the i th  input end  4   a   i  of the NAND gate circuit  4  is at a logical high level, voltages applied to the gate g 1   i  of the i th  PMOS transistor Q 1   i  and the gate g 2   i  of the i th  NMOS transistor Q 2   i  are the voltage of the power supply of the power domain circuit to which the i th  signal output end  5   a   i  belongs. In other words, the voltage of the gate g 1   i  of the i th  PMOS transistor Q 1 , is equal to a voltage of the source s 1   i  of the i th  PMOS transistor Q 1   i , and the i th  PMOS transistor Q 1   1  is cut off. When a voltage, after increasing, of the reference ground of the target power domain circuit  6  does not exceed the voltage of the power supply of the power domain circuit to which the i th  signal output end  5   a   i  belongs, the voltage of the gate g 2   i  of the i th  NMOS transistor Q 2   i  is greater than a voltage of a source s 2   i  of the i th  NMOS transistor Q 2   i , and the i th  NMOS transistor Q 2   i  is turned on. 
     Therefore, when signals transmitted by the n signal output ends  5   a  to the n input ends  4   a  of the NAND gate circuit  4  are all at a logical high level, provided that a voltage, after increasing, of the reference ground of the target power domain circuit  6  does not exceed the voltage of the power supply of each of the plurality of power domain circuits  5 , the n PMOS transistors Q 1  are all cut off, and the n NMOS transistors Q 2  are all turned on. In this way, a voltage of a connection point between the drain d 1  of each of the n PMOS transistors Q 1  and the drain d 2   1  of the first NMOS transistor Q 2   1  is the voltage of the reference ground of the target power domain circuit  6  connected to the source s 2   n  of the n th  NMOS transistor Q 2   n . In an embodiment, a voltage of a signal that is input to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the reference ground of the target power domain circuit  6 . 
     In addition, when the source s 1  of each of the n PMOS transistors Q 1  is connected to the power supply of the target power domain circuit  6 , the n NMOS transistors Q 2  are connected in series, and the source s 2   n  of the n th  NMOS transistor Q 2   n  is connected to the reference ground of the power domain circuit to which the target signal output end  5   a   t  belongs, if a signal transmitted by the target signal output end  5   a   t  to the target input end  4   a   t  of the NAND gate circuit  4  is at a logical low level, voltages applied to a gate g 1   t  of a target PMOS transistor Q 1   t  of the n PMOS transistors Q 1  connected to the target signal output end  5   a   t  and a gate g 2   t  of a target NMOS transistor Q 2   t  of the n NMOS transistors Q 2  are the voltage of the reference ground of the power domain circuit to which the target signal output end  5   a   t  belongs. In this case, the voltage of the gate g 2   t  of the target NMOS transistor Q 2   t  is equal to a voltage of a source s 2   t  of the target NMOS transistor Q 2   t , and the target NMOS transistor Q 2   t  is cut off. When a voltage, after decreasing, of the power supply of the target power domain circuit  6  is not smaller than the voltage of the reference ground of the power domain circuit to which the target signal output end  5   a   t  belongs, the voltage of the gate g 1   t  of the target PMOS transistor Q 1   t  is less than a voltage of a source s 1   t  of the target PMOS transistor Q 1   t , and the target PMOS transistor Q 1   t  is turned on. 
     Therefore, when a signal transmitted by the target signal output ends  5   a   t  to the target input end  4   a   t  of the NAND gate circuit  4  is at a logical low level, provided that a voltage, after decreasing, of the power supply of the target power domain circuit  6  is not smaller than the voltage of the power supply of each of the plurality of power domain circuits  5 , the n NMOS transistors Q 2  are all cut off, and the n PMOS transistors Q 1  are all turned on. In this way, the voltage of the connection point between the drain d 1  of each of the n PMOS transistors Q 1  and the drain d 2   1  of the first NMOS transistor Q 2   1  is the voltage of the power supply of the target power domain circuit  6  connected to the source s 1   t  of the target PMOS transistor Q 1   t . In an embodiment, a voltage of a signal that is input to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the power supply of the target power domain circuit  6 . 
     In this embodiment of the present disclosure, the n input ends of the NAND gate circuit are respectively connected to the n signal output ends of the plurality of power domain circuits, and the output end of the NAND gate circuit is connected to the signal input end of the target power domain circuit. In this case, if the i th  power end of the n power ends of the NAND gate circuit is connected to the power supply of the power domain circuit to which the i th  signal output end of the n signal output ends belongs, and the ground end of the NAND gate circuit is connected to the reference ground of the target power domain circuit, when signals transmitted by the n signal output ends to the n input ends of the NAND gate circuit are all at a logical high level, the voltage of the i th  input end of the n input ends of the NAND gate circuit is equal to the voltage of the i th  power end of the NAND gate circuit. Therefore, even if the voltage of the reference ground of the target power domain circuit changes greatly due to electrostatic interference, provided that a voltage, after increasing, of the reference ground of the target power domain circuit does not exceed the voltage of the power supply of each of the plurality of power domain circuits, the voltage of each of the n power ends of the NAND gate circuit is greater than the voltage of the ground end of the NAND gate circuit, and the voltage of each of the n input ends of the NAND gate circuit is greater than the turnover voltage of the NAND gate circuit. In this case, a voltage of a signal transmitted by the output end of the NAND gate circuit to the signal input end of the target power domain circuit is the voltage of the reference ground of the target power domain circuit. In this way, the signal that is input to the signal input end of the target power domain circuit is at a logical low level in the target power domain circuit, thereby ensuring correct transmission of the logical level of the signal. If the n power ends of the NAND gate circuit are all connected to the power supply of the target power domain circuit, and the ground end of the NAND gate circuit is connected to the reference ground of the power domain circuit to which the target signal output end of the n signal output ends belongs, when a signal transmitted by the target signal output end to the target input end of the n input ends of the NAND gate circuit is at a logical low level, the voltage of the target input end of the NAND gate circuit is equal to the voltage of the ground end of the NAND gate circuit. Therefore, even if the voltage of the power supply of the target power domain circuit changes greatly due to electrostatic interference, provided that a voltage, after decreasing, of the power supply of the target power domain circuit is not smaller than the voltage of the power supply of each of the plurality of power domain circuits, the voltage of each of the n power ends of the NAND gate circuit is greater than the voltage of the ground end of the NAND gate circuit, and the voltage of the target input end of the NAND gate circuit is less than the turnover voltage of the NAND gate circuit. In this case, a voltage of a signal transmitted by the output end of the NAND gate circuit to the signal input end of the target power domain circuit is the voltage of the power supply of the target power domain circuit. In this way, the signal that is input to the signal input end of the target power domain circuit is at a logical high level in the target power domain circuit, thereby ensuring correct transmission of the logical level of the signal. 
     The following describes in detail a third interface circuit provided in an embodiment of the present disclosure. 
       FIG. 4A  and  FIG. 4B  are schematic structural diagrams of an interface circuit according to an embodiment of the present disclosure. Referring to  FIG. 4A  and  FIG. 4B , the interface circuit includes a NOR gate circuit  7 . 
     There are m input ends  7   a  of the NOR gate circuit  7  respectively connected to m signal output ends  5   a  of a plurality of power domain circuits  5 , and an output end  7   b  of the NOR gate circuit  7  is connected to a signal input end  6   a  of a target power domain circuit  6 . The m input ends  7   a  of the NOR gate circuit  7  one-to-one correspond to m ground ends  7   d  of the NOR gate circuit  7 , and m is an integer greater than or equal to 2. 
     Referring to  FIG. 4A , a power end  7   c  of the NOR gate circuit  7  is connected to a power supply of a power domain circuit to which a target signal output end  5   a   t  of the m signal output ends  5   a  belongs, the m ground ends  7   d  of the NOR gate circuit  7  are all connected to a reference ground of the target power domain circuit  6 , and the target signal output end  5   a   t  is connected to a target input end  7   a   t  of the m input ends  7   a  of the NOR gate circuit  7 . Alternatively, referring to  FIG. 4B , a power end  7   c  of the NOR gate circuit  7  is connected to a power supply of the target power domain circuit  6 , a k th  ground end  7   d   k  of the m ground ends  7   d  of the NOR gate circuit  7  is connected to a reference ground of a power domain circuit to which a k th  signal output end  5   a   k  of the m signal output ends  5   a  belongs, and k is an integer greater than or equal to 1 and less than or equal to m. 
     Normally, a voltage of the power end  7   c  of the NOR gate circuit  7  is greater than a voltage of each of the m ground ends  7   d  of the NOR gate circuit  7 . In this case, if a voltage of the target input end  7   a   t  of the NOR gate circuit  7  is greater than a turnover voltage of the NOR gate circuit  7 , a voltage of the output end  7   b  of the NOR gate circuit  7  is a voltage of a target ground end  7   d   t  that is in the m ground ends  7   d  of the NOR gate circuit  7  and that corresponds to the target input end  7   a   t . If a voltage of each of the m input ends  7   a  of the NOR gate circuit  7  is less than the turnover voltage of the NOR gate circuit  7 , the voltage of the output end  7   b  of the NOR gate circuit  7  is the voltage of the power end  7   c  of the NOR gate circuit  7 . 
     It should be noted that the NOR gate circuit  7  is configured for transition between logical states of a signal. Further, the NOR gate circuit  7  is configured to, when any one of a plurality of input signals is at a logical high level, output a signal at a logical low level, or when a plurality of input signals are all at a logical low level, output a signal at a logical high level. 
     In addition, the turnover voltage of the NOR gate circuit  7  is less than a first voltage of the NOR gate circuit  7  and is greater than a second voltage of the NOR gate circuit  7 . The first voltage of the NOR gate circuit  7  is a larger voltage of the voltage of the power end  7   c  of the NOR gate circuit  7  and a smallest voltage of voltages of the m ground ends  7   d  of the NOR gate circuit  7 . The second voltage of the NOR gate circuit  7  is a smaller voltage of the voltage of the power end  7   c  of the NOR gate circuit  7  and the smallest voltage of the voltages of the m ground ends  7   d  of the NOR gate circuit  7 . For example, the turnover voltage of the NOR gate circuit  7  may be half of a sum of the voltage of the power end  7   c  of the NOR gate circuit  7  and the smallest voltage of the voltages of the m ground ends  7   d  of the NOR gate circuit  7 . 
     It should be noted that the plurality of power domain circuits  5  and the target power domain circuit  6  may be different power domain circuits. In an embodiment, the plurality of power domain circuits  5  and the target power domain circuit  6  use power supply solutions independent of each other, or in other words, power supply circuits of the plurality of power domain circuits  5  are different from a power supply circuit of the target power domain circuit  6 . Each of the plurality of power domain circuits  5  may have at least one signal output end, and the plurality of power domain circuits  5  may have the m signal output ends in total. 
     In addition, for a power domain circuit, a voltage of a signal that is output by the power domain circuit at a logical high level is a voltage of a power supply of the power domain circuit, and a voltage of a signal that is output by the power domain circuit at a logical low level is a voltage of a reference ground of the power domain circuit. For example, if a signal that is output by any one of the plurality of power domain circuits  5  is at a logical high level, a voltage of the signal is a voltage of a power supply of the power domain circuit. For another example, if a signal that is output by any one of the plurality of power domain circuits  5  is at a logical low level, a voltage of the signal is a voltage of a reference ground of the power domain circuit. 
     It should be noted that when the power end  7   c  of the NOR gate circuit  7  is connected to the power supply of the power domain circuit to which the target signal output end Sa t  of the m signal output ends  5   a  belongs, and the m ground ends  7   d  of the NOR gate circuit  7  are all connected to the reference ground of the target power domain circuit  6 , the voltage of the power end  7   c  of the NOR gate circuit  7  is a voltage of the power supply of the power domain circuit to which the target signal output end  5   a   t  belongs, and voltages of the m ground ends  7   d  of the NOR gate circuit  7  are all the voltage of the reference ground of the target power domain circuit  6 . In this case, when a signal transmitted by the target signal output end  5   a   t  of the m signal output ends  5   a  to the target input end  7   a   t  of the m input ends  7   a  of the NOR gate circuit  7  is at a logical high level, the voltage of the target input end  7   a   t  of the NOR gate circuit  7  is the voltage of the power supply of the power domain circuit to which the target signal output end  5   a   t  belongs. In other words, the voltage of the target input end  7   a   t  of the NOR gate circuit  7  is equal to the voltage of the power end  7   c  of the NOR gate circuit  7 . Therefore, even if the voltage of the reference ground of the target power domain circuit  6  changes greatly due to electrostatic interference, provided that a voltage, after increasing, of the reference ground of the target power domain circuit  6  does not exceed a voltage of a power supply of each of the plurality of power domain circuits  5 , the voltage of the power end  7   c  of the NOR gate circuit  7  is greater than the voltage of each of the m ground ends  7   d  of the NOR gate circuit  7 , and the voltage of the target input end  7   a   t  of the NOR gate circuit  7  is greater than the turnover voltage of the NOR gate circuit  7 . In this case, the voltage of the output end  7   b  of the NOR gate circuit  7  is the voltage of the target ground end  7   d   t  that is in the m ground ends  7   d  of the NOR gate circuit  7  and that corresponds to the target input end  7   a   t . In an embodiment, a voltage of a signal transmitted by the output end  7   b  of the NOR gate circuit  7  to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the reference ground of the target power domain circuit  6 . 
     When the voltage of the signal transmitted by the output end  7   b  of the NOR gate circuit  7  to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the reference ground of the target power domain circuit  6 , the signal that is input to the signal input end  6   a  of the target power domain circuit  6  is at a logical low level in the target power domain circuit  6 . In this case, at least one of signals that are input by the plurality of power domain circuits  5  to the NOR gate circuit  7  is at a logical high level, and then a signal that is input by the NOR gate circuit  7  to the target power domain circuit  6  is at a logical low level such that the logical level of the signal is correctly transmitted, thereby ensuring stability and reliability of data transmission links between the target power domain circuit  6  and the plurality of power domain circuits  5 , enhancing an electrostatic interference resistance capability of a chip provided with the interface circuit, and improving working performance of the chip. 
     In addition, when the power end  7   c  of the NOR gate circuit  7  is connected to the power supply of the target power domain circuit  6 , and the k th  ground end  7   d   k  of the m ground ends  7   d  of the NOR gate circuit  7  is connected to the reference ground of the power domain circuit to which the k th  signal output end  5   a   k  of the m signal output ends  5   a  belongs, the voltage of the power end  7   c  of the NOR gate circuit  7  is the voltage of the power supply of the target power domain circuit  6 , and a voltage of the k th  ground end  7   d   k  of the m ground ends  7   d  of the NOR gate circuit  7  is the voltage of the reference ground of the power domain circuit to which the k th  signal output end  5   a   k  of the m signal output ends  5   a  belongs. In this case, when signals transmitted by the m signal output ends  5   a  to the m input ends  7   a  of the NOR gate circuit  7  are all at a logical low level, a voltage of a k th  input end  7   a   k  of the m input ends  7   a  of the NOR gate circuit  7  is the voltage of the reference ground of the power domain circuit to which the k th  signal output end  5   a   k  belongs. In other words, the voltage of the k th  input end  7   a   k  of the NOR gate circuit  7  is equal to the voltage of the k th  ground end  7   d   k  of the NOR gate circuit  7 . Therefore, even if the voltage of the power supply of the target power domain circuit  6  changes greatly due to electrostatic interference, provided that a voltage, after decreasing, of the power supply of the target power domain circuit  6  is not smaller than a voltage of a reference ground of each of the plurality of power domain circuits  5 , the voltage of the power end  7   c  of the NOR gate circuit  7  is greater than the voltage of each of the m ground ends  7   d  of the NOR gate circuit  7 , and the voltage of each of the input ends  7   a  of the NOR gate circuit  7  is smaller than the turnover voltage of the NOR gate circuit  7 . In this case, the voltage of the output end  7   b  of the NOR gate circuit  7  is the voltage of the power supply  7   c  of the NOR gate circuit  7 . In an embodiment, a voltage of a signal transmitted by the output end  7   b  of the NOR gate circuit  7  to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the power supply of the target power domain circuit  6 . 
     When the voltage of the signal transmitted by the output end  7   b  of the NOR gate circuit  7  to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the power supply of the target power domain circuit  6 , the signal that is input to the signal input end  6   a  of the target power domain circuit  6  is at a logical high level in the target power domain circuit  6 . In this case, signals that are input by the plurality of power domain circuits  5  to the NOR gate circuit  7  are all at a logical low level, and then a signal that is input by the NOR gate circuit  7  to the target power domain circuit  6  is at a logical high level such that the logical level of the signal is correctly transmitted, thereby ensuring stability and reliability of data transmission links between the target power domain circuit  6  and the plurality of power domain circuits  5 , enhancing an electrostatic interference resistance capability of a chip provided with the interface circuit, and improving working performance of the chip. 
     Referring to  FIG. 4C  and  FIG. 4D , the NOR gate circuit  7  includes m PMOS transistors Q 1  and m NMOS transistors Q 2 . 
     Both a gate g 1   k  of a k th  PMOS transistor Q 1   k  of the m PMOS transistors Q 1  and a gate g 2   k  of a k th  NMOS transistor Q 2   k  of the m NMOS transistors Q 2  are connected to the k th  signal output end  5   a   k . Both a drain d 1   m  of an m th  PMOS transistor Q 1   m  of the m PMOS transistors Q 1  and a drain d 2  of each of the m NMOS transistors Q 2  are connected to the signal input end  6   a  of the target power domain circuit  6 . 
     Referring to  FIG. 4C , a source s 1   1  of a first PMOS transistor Q 1   1  of the m PMOS transistors Q 1  is connected to the power supply of the power domain circuit to which the target signal output end  5   a   t  belongs, the m PMOS transistors Q 1  are connected in series, a source s 2  of each of the m NMOS transistors Q 2  is connected to the reference ground of the target power domain circuit  6 . Alternatively, referring to  FIG. 4D , a source s 1   1  of a first PMOS transistor Q 1   1  is connected to the power supply of the target power domain circuit  6 , the m PMOS transistors Q 1  are connected in series, and a source s 2   k  of the k th  NMOS transistor Q 2   k  is connected to the reference ground of the power domain circuit to which the k th  signal output end  5   a   k  belongs. 
     It should be noted that when the source s 1   1  of the first PMOS transistor Q 1   1  of the m PMOS transistors Q 1  is connected to the power supply of the power domain circuit to which the target signal output end  5   a   t  of the m signal output ends  5   a  belongs, the m PMOS transistors Q 1  are connected in series, and the source s 2  of each of the m NMOS transistors Q 2  is connected to the reference ground of the target power domain circuit  6 , if a signal transmitted by the target signal output end  5   a   t  to the target input end  7   a   t  of the NOR gate circuit  7  is at a logical high level, voltages applied to a gate g 1   t  of a target PMOS transistor Q 1   t  of the m PMOS transistors Q 1  connected to the target signal output end  5   a   t  and a gate g 2   t  of a target NMOS transistor Q 2   t  of the m NMOS transistors Q 2  are the voltage of the power supply of the power domain circuit to which the target signal output end  5   a   t  belongs. In this case, the voltage of the gate g 1   t  of the target PMOS transistor Q 1   t  is equal to a voltage of a source s 1   t  of the target PMOS transistor Q 1   t , and the target PMOS transistor Q 1   t  is cut off. When a voltage, after increasing, of the reference ground of the target power domain circuit  6  does not exceed the voltage of the power supply of the power domain circuit to which the target signal output end  5   a   t  belongs, the voltage of the gate g 2   t  of the target NMOS transistor Q 2   t  is greater than a voltage of a source s 2   t  of the target NMOS transistor Q 2   t , and the target NMOS transistor Q 2   t  is turned on. 
     Therefore, when a signal transmitted by the target signal output end  5   a   t  to the target input end  7   a   t  of the NOR gate circuit  7  is at a logical high level, provided that a voltage, after increasing, of the reference ground of the target power domain circuit  6  does not exceed the voltage of the power supply of each of the plurality of power domain circuits  5 , the m PMOS transistors Q 1  are all cut off, and the m NMOS transistors Q 2  are all turned on. In this way, a voltage of a connection point between the drain d 1   m  of the m th  PMOS transistor Q 1   m  and the drain d 2  of each of the m NMOS transistors Q 2  is the voltage of the reference ground of the target power domain circuit  6  connected to the source s 2   t  of the target NMOS transistor Q 2   t . In an embodiment, a voltage of a signal that is input to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the reference ground of the target power domain circuit  6 . 
     In addition, when the source s 1   1  of the first PMOS transistor Q 1   1  is connected to the power supply of the target power domain circuit  6 , the m PMOS transistors Q 1  are connected in series, and the source s 2   k  of the k th  NMOS transistor Q 2   k  is connected to the reference ground of the power domain circuit to which the k th  signal output end  5   a   k  belongs, if a signal transmitted by the k th  signal output end  5   a   k  to the k th  input end  7   a   k  of the NOR gate circuit  7  is at a logical low level, voltages applied to the gate g 1   k  of the k th  PMOS transistor Q 1   k  and the gate g 2   k  of the k th  NMOS transistor Q 2   k  are the voltage of the reference ground of the power domain circuit to which the k th  signal output end  5   a   k  belongs. In other words, the voltage of the gate g 2   k  of the k th  NMOS transistor Q 2   k  is equal to a voltage of the source s 2   k  of the k th  NMOS transistor Q 2   k , and the k th  NMOS transistor Q 2   k  is cut off. When a voltage, after decreasing, of the power supply of the target power domain circuit  6  is not smaller than the voltage of the reference ground of the power domain circuit to which the k th  signal output end  5   a   k  belongs, the voltage of the gate g 1   k  of the k th  PMOS transistor Q 1   k  is less than a voltage of a source s 1   k  of the k th  PMOS transistor Q 1   k , and the k th  PMOS transistor Q 1   k  is turned on. 
     Therefore, when signals transmitted by the m signal output ends  5   a  to the m input ends  7   a  of the NOR gate circuit  7  are all at a logical low level, provided that a voltage, after decreasing, of the power supply of the target power domain circuit  6  is not smaller than the voltage of the reference ground of each of the plurality of power domain circuits  5 , the m NMOS transistors Q 2  are all cut off, and the m PMOS transistors Q 1  are all conducted. In this way, the voltage of the connection point between the drain d 1   m  of the M th  PMOS transistor Q 1   m  and the drain d 2  of each NMOS transistor Q 2  of the m NMOS transistors Q 2  is the voltage of the power supply of the target power domain circuit  6  connected to the source s 1   m  of the M th  PMOS transistor Q 1   m . In an embodiment, a voltage of a signal that is input to the signal input end  6   a  of the target power domain circuit  6  is the voltage of the power supply of the target power domain circuit  6 . 
     In this embodiment of the present disclosure, the m input ends of the NOR gate circuit are respectively connected to the m signal output ends of the plurality of power domain circuits, and the output end of the NOR gate circuit is connected to the signal input end of the target power domain circuit. In this case, if the power end of the NOR gate circuit is connected to the power supply of the power domain circuit to which the target signal output end of the m signal output ends belongs, and the m ground ends of the NOR gate circuit are all connected to the reference ground of the target power domain circuit, when a signal transmitted by the target signal output end of the m signal output ends to the target input end of the m input ends of the NOR gate circuit is at a logical high level, the voltage of the target input end of the NOR gate circuit is equal to the voltage of the power end of the NOR gate circuit. Therefore, even if the voltage of the reference ground of the target power domain circuit changes greatly due to electrostatic interference, provided that a voltage, after increasing, of the reference ground of the target power domain circuit does not exceed the voltage of the power supply of each of the plurality of power domain circuits, the voltage of the power end of the NOR gate circuit is greater than the voltage of each of the m ground ends of the NOR gate circuit, and the voltage of the target input end of the NOR gate circuit is greater than the turnover voltage of the NOR gate circuit. In this case, a voltage of a signal transmitted by the output end of the NOR gate circuit to the signal input end of the target power domain circuit is the voltage of the reference ground of the target power domain circuit. In this way, the signal that is input to the signal input end of the target power domain circuit is at a logical low level in the target power domain circuit, thereby ensuring correct transmission of the logical level of the signal. If the power end of the NOR gate circuit is connected to the power supply of the target power domain circuit, and the k th  ground end of the m ground ends of the NOR gate circuit is connected to the reference ground of the power domain circuit to which the k th  signal output end of the m signal output ends belongs, when signals transmitted by the m signal output ends to the m input ends of the NOR gate circuit are all at a logical low level, the voltage of the k th  input end of the NOR gate circuit is equal to the voltage of the k th  ground end of the NOR gate circuit. Therefore, even if the voltage of the power supply of the target power domain circuit changes greatly due to electrostatic interference, provided that a voltage, after decreasing, of the power supply of the target power domain circuit is not smaller than the voltage of the reference ground of each of the plurality of power domain circuits, the voltage of the power end of the NOR gate circuit is greater than the voltage of each of the m ground ends of the NOR gate circuit, and the voltage of each of the m input ends of the NOR gate circuit is less than the turnover voltage of the NOR gate circuit. In this case, a voltage of a signal transmitted by the output end of the NOR gate circuit to the signal input end of the target power domain circuit is the voltage of the power supply of the target power domain circuit. In this way, the signal that is input to the signal input end of the target power domain circuit is at a logical high level in the target power domain circuit, thereby ensuring correct transmission of the logical level of the signal. 
     The foregoing descriptions are merely embodiments provided in this application, but are not intended to limit this application. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of this application should fall within the protection scope of this application.