Patent Publication Number: US-11658494-B2

Title: Charging method and related device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/828,508 filed on Mar. 24, 2020, which is a continuation of U.S. patent application Ser. No. 16/095,848 filed on Oct. 23, 2018, now U.S. Pat. No. 10,630,091. U.S. patent application Ser. No. 16/095,848 is a national stage of International Patent Application No. PCT/CN2016/105856 filed on Nov. 15, 2016. All of the aforementioned patent applications are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present invention relates to the field of electronic technologies, and in particular, to a charging method and a related device. 
     BACKGROUND 
     With rapid development of electronic technologies, upgrading of user terminals accelerates. For example, commonly used user terminals such as mobile phones, tablet computers, wearable devices have become an important part of people&#39;s daily life. Most user terminals need to be charged by using a power supply device. In an example of a mobile phone, one Universal Serial Bus (Universal Serial Bus, USB) port, on a charging data cable, that is used to connect to a power source and that matches the mobile phone is connected to a power source charger or a computer, and the other USB port on the charging data cable is connected to a charging port of the mobile phone, to charge the mobile phone. 
     In an actual application, in a charging process of the user terminal, a leakage current at the charging port, an extremely high current, and an extremely high voltage may cause damage to the mobile phone to some extent. In an existing technical solution, a protection circuit designed inside the user terminal can protect the user terminal from the extremely high current or the extremely high voltage. However, in a case of a short circuit at the charging port, before flowing into the protection circuit inside the user terminal, some currents flowing through the charging port are short-circuited to ground. In this case, if a current detected by the protection circuit does not exceed a preset current threshold, the protection circuit considers that charging is normal, and the user terminal remains in a charging state. This causes the charging port to be burned due to the extremely high current, and reduces charging security of the user terminal. 
     SUMMARY 
     Embodiments of the present invention provide a charging method and a related device. A charging current is monitored in real time, so that a user terminal monitors whether a leakage current exists in a current charging process, and in a case of the leakage current, a power cable is disconnected in time by using a charge protection apparatus, so as to protect the user terminal. 
     According to a first aspect, an embodiment of the present invention provides a charge protection apparatus, where the charge protection apparatus is connected to a charging cable, and the charging cable includes a power cable and a data cable; 
     the charge protection apparatus includes a micro control unit MCU, a current detection circuit, a gating circuit, and an I/O interface; 
     the current detection circuit and the gating circuit are disposed on the power cable; if the gating circuit is in a closed state, the power cable is not disconnected from charging, or if the gating circuit is in an open state, the power cable is disconnected from charging; the I/O interface and the data cable are connected; and the MCU sends data by using the I/O interface; and 
     the current detection circuit detects an external charging current flowing through the power cable; the current detection circuit transmits the external charging current to the MCU; the MCU transmits the external charging current to a user terminal by using the I/O interface, so that the user terminal calculates a current difference between the external charging current and an internal charging current detected by the user terminal, and determines, based on the current difference, whether to generate a circuit control command; and the MCU receives the circuit control command sent by the user terminal, and controls, according to the circuit control command, the gating circuit to be in the closed state or the open state. 
     According to the first aspect of the embodiments of the present invention, a charging current is monitored in real time, so that the user terminal monitors whether a leakage current exists in a current charging process, and in a case of the leakage current, the power cable is disconnected from charging in time by using the charge protection apparatus, so as to protect the user terminal. 
     With reference to the first aspect, in a first implementation of the first aspect, the charge protection apparatus further includes a temperature detection circuit; 
     the temperature detection circuit detects a temperature of the charging cable, and transmits the temperature of the charging cable to the MCU; and the MCU transmits the temperature of the charging cable to the user terminal by using the I/O interface, so that the user terminal determines, based on the temperature of the charging cable, whether to generate the circuit control command; and 
     the MCU receives the circuit control command sent by the user terminal, and controls, according to the circuit control command, the gating circuit to be in the closed state or the open state. 
     Optionally, the charge protection apparatus is disposed at a position close to a USB port connected to a charging port of the user terminal, so that the temperature detection circuit can more accurately detect the temperature of the charging port of the user terminal. 
     With reference to the first aspect or the first implementation of the first aspect, in a second implementation of the first aspect, the charge protection apparatus further includes a voltage detection circuit, and the voltage detection circuit is disposed on the power cable; 
     the voltage detection circuit detects an external charging voltage of the power cable, and transmits the external charging voltage to the MCU; and the MCU transmits the external charging voltage to the user terminal by using the I/O interface, so that the user terminal determines, based on the external charging voltage, whether to generate the circuit control command; and 
     the MCU receives the circuit control command sent by the user terminal, and controls, according to the circuit control command, the gating circuit to be in the closed state or the open state. 
     With reference to the first aspect, the first implementation of the first aspect, or the second implementation of the first aspect, in a third implementation of the first aspect, the controlling, according to the circuit control command, the gating circuit to be in the closed state or the open state includes: 
     if the circuit control command is to keep charging, the MCU controls the gating circuit to be in the closed state; or if the circuit control command is to disconnect from charging, the MCU controls the gating circuit to be in the open state. 
     With reference to the first aspect, the first implementation of the first aspect, the second implementation of the first aspect, or the third implementation of the first aspect, in a fourth implementation of the first aspect, the charge protection apparatus further includes a prompt circuit, the charge protection apparatus further includes a buzzer, an indicator, and/or an oscillator, and the prompt circuit is configured to control whether the buzzer rings, control whether the indicator flickers, and/or control whether the oscillator oscillates; and 
     if a first warning prompt is set in the circuit control command, the MCU performs a warning operation according to the first warning prompt by using the prompt circuit. 
     Optionally, the first warning prompt carries a first time interval for a first prompt mode and a second time interval for a second prompt mode; and that the MCU controls, according to the first warning prompt by using the prompt circuit, the buzzer to ring and the indicator to flicker is specifically: the MCU performs, based on a time interval for each prompt mode by using the prompt circuit, an operation corresponding to each prompt mode. 
     Optionally, the prompt circuit is configured to control whether the buzzer rings, control whether the indicator flickers, and/or control whether the oscillator oscillates. The charge protection apparatus may include one or more of the buzzer, the indicator, and the oscillator. It may be understood that, if the buzzer is included, the first warning prompt may include a prompt mode in which the buzzer rings; if the indicator is included, the first warning prompt may include a prompt mode in which the indicator flickers; or if the oscillator is included, the first warning prompt may include a prompt mode in which the oscillator oscillates. 
     Further, optionally, when the first warning prompt may include a plurality of prompt modes, one or more of the prompt modes may be selected for prompting. This is not limited in this embodiment of the present invention. In this way, a user is prompted in the prompt mode, so that the user can learn of a current charging status in time. 
     With reference to the first aspect, the first implementation of the first aspect, the second implementation of the first aspect, the third implementation of the first aspect, or the fourth implementation of the first aspect, in a fifth implementation of the first aspect, the charge protection apparatus further includes a port status detection circuit, and the port status detection circuit and the gating circuit are connected in parallel; and 
     when the gating circuit is in the open state, if the port status detection circuit detects that the gating circuit is disconnected from the power supply apparatus or is disconnected from the charging port of the user terminal, the port status detection circuit notifies the MCU that the port connection has been broken, and the MCU controls the gating circuit to be in the closed state. 
     Optionally, the port status detection circuit may include a current limiting resistor and a micro current detection circuit. Because the port status detection circuit and the gating circuit are connected in parallel, the port status detection circuit is equivalent to another closed circuit on the power cable. However, herein, setting a resistance value of the current limiting resistor can enable a current of the closed circuit to be at a milliampere scale or even smaller, and the current can be detected by using the micro current detection circuit. Therefore, once the gating circuit is in the open state, the port status detection circuit notifies the MCU that the gating circuit is disconnected from the charging port, so that the MCU controls the gating circuit to restore to the closed state, helping the charge protection apparatus perform protection for a next charging connection. 
     According to a second aspect, an embodiment of the present invention provides a charging data cable, where the charging data cable includes the charge protection apparatus provided in the first aspect. In this embodiment of the present invention, the charging data cable may receive a circuit control command that is generated by a user terminal based on a result of comparison between an internal charging current and an external charging current, and further control whether a power cable is disconnected from charging, so as to protect the user terminal. The charge protection apparatus is usually disposed near a port of the user terminal on the charging data cable. 
     According to a third aspect, an embodiment of the present invention provides a charger, where the charger includes the charge protection apparatus provided in the first aspect. In this embodiment of the present invention, the charger may receive a circuit control command that is generated by a user terminal based on a result of comparison between an internal charging current and an external charging current, and further control whether a power cable is disconnected from charging, so as to protect the user terminal. 
     According to a fourth aspect, an embodiment of the present invention provides a charge protection apparatus, where the charge protection apparatus is connected to a charging cable, the charging cable includes a power cable and a data cable, and the charge protection apparatus includes a detection unit, a sending unit, a receiving unit, and a control unit; 
     the control unit is configured to detect an external charging current of the power cable by using the detection unit; 
     the control unit is further configured to send the external charging current to a user terminal by using the sending unit, so that the user terminal calculates a current difference between the external charging current and an internal charging current detected by the user terminal, and determines, based on the current difference, whether to generate a circuit control command; 
     the control unit is further configured to receive, by using the receiving unit, the circuit control command sent by the user terminal; and 
     the control unit is further configured to control, according to the circuit control command, whether the power cable is disconnected from charging. 
     According to the fourth aspect of the embodiments of the present invention, a charging current is monitored in real time, so that the user terminal monitors whether a leakage current exists in a current charging process, and in a case of the leakage current, the power cable is disconnected from charging in time by using the charge protection apparatus, so as to protect the user terminal. 
     With reference to the fourth aspect, in a first implementation of the fourth aspect, the control unit is further configured to: detect a temperature of the charging cable by using the detection unit, and send the temperature of the charging cable to the user terminal, so that the user terminal determines, based on the temperature of the charging cable, whether to generate the circuit control command. Therefore, a charging port can be better protected by performing temperature detection. 
     With reference to the fourth aspect or the first implementation of the fourth aspect, in a second implementation of the fourth aspect, the control unit is further configured to: detect an external charging voltage of the power cable by using the detection unit, and send the external charging voltage to the user terminal, so that the user terminal determines, based on the external charging voltage, whether to generate the circuit control command. The user terminal can be better protected by performing external charging voltage detection. 
     With reference to the fourth aspect, the first implementation of the fourth aspect, or the second implementation of the fourth aspect, in a third implementation of the fourth aspect, with regard to the controlling, according to the circuit control command, whether the power cable is disconnected from charging, the control unit is specifically configured to: 
     if the circuit control command is to keep charging, control the power cable to remain in a charging connection; or if the circuit control command is to disconnect from charging, control the power cable to disconnect from charging. It may be understood that, if the circuit control command sent by the user terminal is not received, the charging data cable remains in a charging state, and in this case, the power cable remains in the charging connection. 
     With reference to the third implementation of the fourth aspect, in a fourth implementation of the fourth aspect, the control unit is further configured to: if a first warning prompt is set in the circuit control command, perform a warning operation according to the first warning prompt. 
     Optionally, at least one prompt mode and a time interval for executing each prompt mode are set in the first warning prompt; and 
     the control unit is specifically configured to: if the first warning prompt is set in the circuit control command, perform, based on the time interval for each prompt mode, an operation corresponding to each prompt mode. 
     Optionally, when the first warning prompt may include a plurality of prompt modes, one or more of the prompt modes may be selected for prompting. This is not limited in this embodiment of the present invention. In this way, a user is prompted in the prompt mode, so that the user can learn of a current charging status in time. 
     With reference to the fourth aspect, the first implementation of the fourth aspect, the second implementation of the fourth aspect, the third implementation of the fourth aspect, or the fourth implementation of the fourth aspect, in a fifth implementation of the fourth aspect, the control unit is further configured to: when the power cable is disconnected from charging, if it is detected that the power cable is disconnected from the power supply apparatus or is disconnected from the charging port of the user terminal, control the power cable to establish a charging connection. 
     According to a fifth aspect, an embodiment of the present invention provides a charging data cable, where the charging data cable includes the charge protection apparatus provided in the first aspect. In this embodiment of the present invention, the charging data cable may receive a circuit control command that is generated by a user terminal based on a result of comparison between an internal charging current and an external charging current, and further control whether a power cable is disconnected from charging, so as to protect the user terminal. The charge protection apparatus is usually disposed near a port of the user terminal on the charging data cable. 
     According to a sixth aspect, an embodiment of the present invention provides a charger, where the charger includes the charge protection apparatus provided in the first aspect. In this embodiment of the present invention, the charger may receive a circuit control command that is generated by a user terminal based on a result of comparison between an internal charging current and an external charging current, and further control whether a power cable is disconnected from charging, so as to protect the user terminal. 
     According to a seventh aspect, an embodiment of the present invention provides a user terminal, including a detection unit, a receiving unit, a processing unit, and a sending unit; 
     the processing unit is configured to detect an internal charging current by using the detection unit; 
     the processing unit is further configured to receive, by using the receiving unit, an external charging current sent by the charge protection apparatus; 
     the processing unit is further configured to calculate a current difference between the external charging current and the internal charging current; 
     the processing unit is further configured to determine, based on the current difference, whether to generate a circuit control command; and 
     the processing unit is further configured to: if the circuit control command is generated, send the circuit control command to the charge protection apparatus by using the sending unit. 
     According to the seventh aspect of the embodiments of the present invention, a charging current is monitored in real time, so that the user terminal monitors whether a leakage current exists in a current charging process, and in a case of the leakage current, a power cable is disconnected from charging in time by using the charge protection apparatus, so as to protect the user terminal. 
     With reference to the seventh aspect, in a first implementation of the seventh aspect, with regard to the determining, based on the current difference, whether to generate a circuit control command, the processing unit is specifically configured to: 
     if the current difference is greater than a first current threshold and less than a second current threshold, determine that the generated circuit control command is to keep charging; or if the current difference is greater than the second current threshold and less than a third current threshold, determine that the generated circuit control command is to disconnect from charging. 
     It may be understood that, if the current difference is less than the first current threshold, the user terminal does not generate the circuit control command. 
     With reference to the first implementation of the seventh aspect, in a second implementation of the seventh aspect, the user terminal further includes a first output unit; 
     the processing unit is further configured to: if the current difference is greater than the first current threshold and less than the second current threshold, output a first pop-up prompt on a screen by using the first output unit, where the first pop-up prompt is a prompt message used to indicate that the current difference exists in a current charging process; and 
     the processing unit is further configured to: if the current difference is greater than the second current threshold and less than the third current threshold, output a second pop-up prompt on the screen by using the first output unit, where the second pop-up prompt is a prompt message used to indicate that the current difference exists in the current charging process and charging is disconnected. 
     The pop-up prompt may be used to instruct a user to check in time whether there is a problem of liquid intake, corrosion, or the like for a charging port of the user terminal. 
     With reference to the seventh aspect, the first implementation of the seventh aspect, or the second implementation of the seventh aspect, in a third implementation of the seventh aspect, the processing unit is further configured to receive, by using the receiving unit, a temperature of a charging cable that is sent by the charge protection apparatus; and the processing unit is further configured to determine, based on the temperature of the charging cable, whether to generate the circuit control command. The charging port can be better protected by using a temperature detection mechanism. 
     With reference to the third implementation of the seventh aspect, in a fourth implementation of the seventh aspect, with regard to the determining, based on the temperature of the charging cable, whether to generate the circuit control command, the processing unit is specifically configured to: 
     if the temperature of the charging cable is greater than a first temperature threshold and less than a second temperature threshold, determine that the generated circuit control command is to keep charging; or if the temperature of the charging cable is greater than the second temperature threshold, determine that the generated circuit control command is to disconnect from charging. 
     It may be understood that, if the temperature of the charging cable is less than the first temperature threshold, the user terminal does not generate the circuit control command. 
     With reference to the fourth implementation of the seventh aspect, in a fifth implementation of the seventh aspect, the user terminal further includes a second output unit; 
     the processing unit is further configured to: if the temperature of the charging cable is greater than the first temperature threshold and less than the second temperature threshold, output a third pop-up prompt on the screen by using the second output unit, where the third pop-up prompt is a prompt message used to indicate that the temperature of the charging cable is extremely high in the current charging process; and 
     the processing unit is further configured to: if the temperature of the charging cable is greater than the second temperature threshold and less than the third temperature threshold, output a fourth pop-up prompt on the screen by using the second output unit, where the fourth pop-up prompt is a prompt message used to indicate that the temperature of the charging cable is extremely high in the current charging process and charging is disconnected. 
     The pop-up prompt may be used to instruct the user to check in time whether there is a problem of liquid intake, corrosion, or the like for the charging port of the user terminal. 
     With reference to the seventh aspect, the first implementation of the seventh aspect, the second implementation of the seventh aspect, the third implementation of the seventh aspect, the fourth implementation of the seventh aspect, or the fifth implementation of the seventh aspect, in a sixth implementation of the seventh aspect, the processing unit is further configured to receive, by using the receiving unit, an external charging voltage sent by the charge protection apparatus; and 
     the processing unit is further configured to determine, based on the external charging voltage, whether to generate the circuit control command. The user terminal can be better protected by performing external charging voltage detection. 
     With reference to the sixth implementation of the seventh aspect, in a seventh implementation of the seventh aspect, with regard to the determining, based on the external charging voltage, whether to generate the circuit control command, the processing unit is specifically configured to: 
     if the external charging voltage is greater than a first voltage threshold and less than a second voltage threshold, determine that the generated circuit control command is to keep charging; or if the external charging voltage is greater than the second voltage threshold, determine that the generated circuit control command is to disconnect from charging. 
     It may be understood that, if the external charging voltage of the power cable is less than the first voltage threshold, the user terminal does not generate the circuit control command. 
     With reference to the seventh implementation of the seventh aspect, in an eighth implementation of the seventh aspect, the user terminal further includes a third output unit; 
     the processing unit is further configured to: if the external charging voltage is greater than the first voltage threshold and less than the second voltage threshold, output a fifth pop-up prompt on the screen by using the third output unit, where the fifth pop-up prompt is a prompt message used to indicate that the external charging voltage is extremely high in the current charging process; and 
     the processing unit is further configured to: if the external charging voltage is greater than the second voltage threshold and less than the third voltage threshold, output a sixth pop-up prompt on the screen by using the third output unit, where the sixth pop-up prompt is a prompt message used to indicate that the external charging voltage is extremely high in the current charging process and charging is disconnected. 
     The pop-up prompt may be used to instruct the user to check in time whether there is a problem of liquid intake, corrosion, or the like for the charging port of the user terminal. 
     Optionally, the user terminal further includes a fourth output unit; and the processing unit is further configured to output the internal charging current, the external charging current, and the external charging voltage on the screen by using the fourth output unit. 
     Optionally, the processing unit may output at least one of the internal charging current, the external charging current, and the external charging voltage. 
     Optionally, a first warning prompt is set in the circuit control command, and the first warning prompt is used to instruct the charge protection apparatus to perform a warning operation according to the first warning prompt. Further, optionally, at least one prompt mode and a time interval for executing each prompt mode are set in the first warning prompt. 
     With reference to the seventh aspect, the first implementation of the seventh aspect, the second implementation of the seventh aspect, the third implementation of the seventh aspect, the fourth implementation of the seventh aspect, the fifth implementation of the seventh aspect, the sixth implementation of the seventh aspect, the seventh implementation of the seventh aspect, or the eighth implementation of the seventh aspect, in a ninth implementation of the seventh aspect, the processing unit is further configured to perform a warning operation based on a preset second warning prompt if the circuit control command is generated, where the second warning prompt includes at least one prompt mode. For example, the prompt mode may include one or more of a sound prompt mode, a flicker prompt mode, and an oscillation prompt mode, and the prompt mode in the second warning prompt is not limited to these prompt modes. The circuit control command may be a command for keeping charging or disconnecting from charging, and therefore the user terminal may set different prompt modes for different commands. In this way, the user is prompted in the prompt mode, so that the user can learn of a current charging status in time. 
     According to an eighth aspect, an embodiment of the present invention provides a charging method, where the method is applied to a charge protection apparatus, a charging cable in the charge protection apparatus includes a power cable and a data cable, and the method includes: 
     detecting, by the charge protection apparatus, an external charging current of the power cable; 
     sending, by the charge protection apparatus, the external charging current to a user terminal, so that the user terminal calculates a current difference between the external charging current and an internal charging current detected by the user terminal, and determines, based on the current difference, whether to generate a circuit control command; 
     receiving, by the charge protection apparatus, the circuit control command sent by the user terminal; and 
     controlling, by the charge protection apparatus according to the circuit control command, whether the power cable is disconnected from charging. 
     According to the eighth aspect of the embodiments of the present invention, a charging current is monitored in real time, so that the user terminal monitors whether a leakage current exists in a current charging process, and in a case of the leakage current, the power cable is disconnected from charging in time by using the charge protection apparatus, so as to protect the user terminal. 
     With reference to the eighth aspect, in a first implementation of the eighth aspect, before the receiving, by the charge protection apparatus, the circuit control command sent by the user terminal, the method further includes: 
     detecting, by the charge protection apparatus, a temperature of the charging cable, and sending the temperature of the charging cable to the user terminal, so that the user terminal determines, based on the temperature of the charging cable, whether to generate the circuit control command. Therefore, a charging port can be better protected by performing temperature detection. 
     With reference to the eighth aspect or the first implementation of the eighth aspect, in a second implementation of the eighth aspect, before the receiving, by the charge protection apparatus, the circuit control command sent by the user terminal, the method further includes: 
     detecting, by the charge protection apparatus, an external charging voltage of the power cable, and sending the external charging voltage to the user terminal, so that the user terminal determines, based on the external charging voltage, whether to generate the circuit control command. The user terminal can be better protected by performing external charging voltage detection. 
     With reference to the eighth aspect, the first implementation of the eighth aspect, or the second implementation of the eighth aspect, in a third implementation of the eighth aspect, the controlling, by the charge protection apparatus according to the circuit control command, whether the power cable is disconnected from charging includes: 
     if the circuit control command is to keep charging, controlling, by the charge protection apparatus, the power cable to remain in a charging connection; or if the circuit control command is to disconnect from charging, controlling, by the charge protection apparatus, the power cable to disconnect from charging. It may be understood that, if the circuit control command sent by the user terminal is not received, the charging data cable remains in a charging state, and in this case, the power cable remains in the charging connection. 
     With reference to the third implementation of the eighth aspect, in a fourth implementation of the eighth aspect, the method further includes: 
     performing, by the charge protection apparatus if a first warning prompt is set in the circuit control command, a warning operation according to the first warning prompt. 
     Optionally, at least one prompt mode and a time interval for executing each prompt mode are set in the first warning prompt; and the performing, by the charge protection apparatus if a first warning prompt is set in the circuit control command, a warning operation according to the first warning prompt includes: if the first warning prompt is set in the circuit control command, performing, by the charge protection apparatus based on the time interval for each prompt mode, an operation corresponding to each prompt mode. 
     Optionally, when the first warning prompt may include a plurality of prompt modes, one or more of the prompt modes may be selected for prompting. This is not limited in this embodiment of the present invention. In this way, a user is prompted in the prompt mode, so that the user can learn of a current charging status in time. 
     With reference to the eighth aspect, the first implementation of the eighth aspect, the second implementation of the eighth aspect, the third implementation of the eighth aspect, or the fourth implementation of the eighth aspect, in a fifth implementation of the eighth aspect, the method further includes: 
     when the power cable is disconnected from charging, if it is detected that the power cable is disconnected from the power supply apparatus or is disconnected from the charging port of the user terminal, controlling, by the charge protection apparatus, the power cable to establish a charging connection. 
     According to a ninth aspect, an embodiment of the present invention provides a charging method, including: 
     detecting, by a user terminal, an internal charging current; 
     receiving, by the user terminal, an external charging current sent by the charge protection apparatus; 
     calculating, by the user terminal, a current difference between the external charging current and the internal charging current; 
     determining, by the user terminal based on the current difference, whether to generate a circuit control command; and 
     sending, by the user terminal, the circuit control command to the charge protection apparatus if the circuit control command is generated. 
     According to the ninth aspect of the embodiments of the present invention, a charging current is monitored in real time, so that the user terminal monitors whether a leakage current exists in a current charging process, and in a case of the leakage current, a power cable is disconnected from charging in time by using the charge protection apparatus, so as to protect the user terminal. 
     With reference to the ninth aspect, in a first implementation of the ninth aspect, the determining, by the user terminal based on the current difference, whether to generate a circuit control command includes: 
     if the current difference is greater than a first current threshold and less than a second current threshold, determining, by the user terminal, that the generated circuit control command is to keep charging; or if the current difference is greater than the second current threshold and less than a third current threshold, determining, by the user terminal, that the generated circuit control command is to disconnect from charging. 
     It may be understood that, if the current difference is less than the first current threshold, the user terminal does not generate the circuit control command. 
     With reference to the first implementation of the ninth aspect, in a second implementation of the ninth aspect, the method further includes: 
     if the current difference is greater than the first current threshold and less than the second current threshold, outputting, by the user terminal, a first pop-up prompt on a screen, where the first pop-up prompt is a prompt message used to indicate that the current difference exists in a current charging process; or if the current difference is greater than the second current threshold and less than the third current threshold, outputting, by the user terminal, a second pop-up prompt on the screen, where the second pop-up prompt is a prompt message used to indicate that the current difference exists in the current charging process and charging is disconnected. 
     The pop-up prompt may be used to instruct a user to check in time whether there is a problem of liquid intake, corrosion, or the like for a charging port of the user terminal. 
     With reference to the ninth aspect, the first implementation of the ninth aspect, or the second implementation of the ninth aspect, in a third implementation of the ninth aspect, before the sending, by the user terminal, the circuit control command to the charge protection apparatus if the circuit control command is generated, the method further includes: 
     receiving, by the user terminal, a temperature of a charging cable that is sent by the charge protection apparatus; and determining, by the user terminal based on the temperature of the charging cable, whether to generate the circuit control command. The charging port can be better protected by using a temperature detection mechanism. 
     With reference to the third implementation of the ninth aspect, in a fourth implementation of the ninth aspect, the determining, by the user terminal based on the temperature of the charging cable, whether to generate the circuit control command includes: 
     if the temperature of the charging cable is greater than a first temperature threshold and less than a second temperature threshold, determining, by the user terminal, that the generated circuit control command is to keep charging; or if the temperature of the charging cable is greater than the second temperature threshold, determining, by the user terminal, that the generated circuit control command is to disconnect from charging. 
     It may be understood that, if the temperature of the charging cable is less than the first temperature threshold, the user terminal does not generate the circuit control command. 
     With reference to the fourth implementation of the ninth aspect, in a fifth implementation of the ninth aspect, the method further includes: 
     if the temperature of the charging cable is greater than the first temperature threshold and less than the second temperature threshold, outputting, by the user terminal, a third pop-up prompt on the screen, where the third pop-up prompt is a prompt message used to indicate that the temperature of the charging cable is extremely high in the current charging process; or if the temperature of the charging cable is greater than the second temperature threshold and less than the third temperature threshold, outputting, by the user terminal, a fourth pop-up prompt on the screen, where the fourth pop-up prompt is a prompt message used to indicate that the temperature of the charging cable is extremely high in the current charging process and charging is disconnected. 
     The pop-up prompt may be used to instruct the user to check in time whether there is a problem of liquid intake, corrosion, or the like for the charging port of the user terminal. 
     With reference to the ninth aspect, the first implementation of the ninth aspect, the second implementation of the ninth aspect, the third implementation of the ninth aspect, the fourth implementation of the ninth aspect, or the fifth implementation of the ninth aspect, in a sixth implementation of the ninth aspect, before the sending, by the user terminal, the circuit control command to the charge protection apparatus if the circuit control command is generated, the method further includes: 
     receiving, by the user terminal, an external charging voltage sent by the charge protection apparatus; and determining, based on the external charging voltage, whether to generate the circuit control command. The user terminal can be better protected by performing external charging voltage detection. 
     With reference to the sixth implementation of the ninth aspect, in a seventh implementation of the ninth aspect, the determining, by the user terminal based on the external charging voltage, whether to generate the circuit control command includes: 
     if the external charging voltage is greater than a first voltage threshold and less than a second voltage threshold, determining, by the user terminal, that the generated circuit control command is to keep charging; or if the external charging voltage is greater than the second voltage threshold, determining, by the user terminal, that the generated circuit control command is to disconnect from charging. 
     It may be understood that, if the external charging voltage of the power cable is less than the first voltage threshold, the user terminal does not generate the circuit control command. 
     With reference to the seventh implementation of the ninth aspect, in an eighth implementation of the ninth aspect, the method further includes: 
     if the external charging voltage is greater than the first voltage threshold and less than the second voltage threshold, outputting, by the user terminal, a fifth pop-up prompt on the screen, where the fifth pop-up prompt is a prompt message used to indicate that the external charging voltage is extremely high in the current charging process; or if the external charging voltage is greater than the second voltage threshold and less than the third voltage threshold, outputting, by the user terminal, a sixth pop-up prompt on the screen, where the sixth pop-up prompt is a prompt message used to indicate that the external charging voltage is extremely high in the current charging process and charging is disconnected. 
     The pop-up prompt may be used to instruct the user to check in time whether there is a problem of liquid intake, corrosion, or the like for the charging port of the user terminal. 
     Optionally, the method further includes: outputting the internal charging current, the external charging current, and the external charging voltage on the screen. Further, optionally, the processing unit may output at least one of the internal charging current, the external charging current, and the external charging voltage. 
     Optionally, a first warning prompt is set in the circuit control command, and the first warning prompt is used to instruct the charge protection apparatus to perform a warning operation according to the first warning prompt. Further, optionally, at least one prompt mode and a time interval for executing each prompt mode are set in the first warning prompt. 
     With reference to the ninth aspect, the first implementation of the ninth aspect, the second implementation of the ninth aspect, the third implementation of the ninth aspect, the fourth implementation of the ninth aspect, the fifth implementation of the ninth aspect, the sixth implementation of the ninth aspect, the seventh implementation of the ninth aspect, or the eighth implementation of the ninth aspect, in a ninth implementation of the ninth aspect, the method further includes: 
     performing, by the user terminal, a warning operation based on a preset second warning prompt if the circuit control command is generated, where the second warning prompt includes at least one prompt mode. For example, the prompt mode may include one or more of a sound prompt mode, a flicker prompt mode, and an oscillation prompt mode, and the prompt mode in the second warning prompt is not limited to these prompt modes. The circuit control command may be a command for keeping charging or disconnecting from charging, and therefore the user terminal may set different prompt modes for different commands. In this way, the user is prompted in the prompt mode, so that the user can learn of a current charging status in time. 
     According to a tenth aspect, an embodiment of the present invention provides another user terminal, the user terminal includes a processor, a charging control IC, and a transceiver, and the processor is configured to execute the charging method provided in the fifth aspect of the present invention. Optionally, the user terminal may further include a memory, a display system, an audio frequency system, and/or an oscillator; the memory is configured to store application program code used for supporting a user terminal in executing the foregoing method; and the processor is configured to execute an application program stored in the memory. 
     According to an eleventh aspect, an embodiment of the present invention provides a computer storage medium, configured to store a computer software instruction used by the charge protection apparatus. The computer software instruction includes a program that is designed for executing the foregoing aspects. 
     According to a twelfth aspect, an embodiment of the present invention provides a computer storage medium, configured to store a computer software instruction used by the user terminal. The computer software instruction includes a program that is designed for executing the foregoing aspects. 
     In the embodiments of the present invention, names of the charging data cable and the user terminal impose no limitation on the devices. In an actual application, these devices may have other names, provided that functions of the devices are similar to those in the present invention and fall within the scope defined by the following claims and equivalent technologies of the present invention. 
     In the embodiments of the present invention, a charging current is monitored in real time, so that the user terminal monitors whether a leakage current exists in the current charging process, and in a case of the leakage current, the power cable is disconnected from charging in time by using the charge protection apparatus, so as to protect the user terminal. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       To describe the technical solutions in the embodiments of the present invention or in the prior art more clearly, the following briefly describes the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present invention, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts. 
         FIG.  1    is a possible schematic diagram of charging; 
         FIG.  2    is a schematic structural diagram of a charge protection apparatus according to an embodiment of the present invention; 
         FIG.  3   a    is an example diagram of charging according to an embodiment of the present invention; 
         FIG.  3   b    is another example diagram of charging according to an embodiment of the present invention; 
         FIG.  4    is a schematic flowchart of a charging method according to an embodiment of the present invention; 
         FIG.  5   a    is an example diagram of a prompt according to an embodiment of the present invention; 
         FIG.  5   b    is an example diagram of another prompt according to an embodiment of the present invention; 
         FIG.  6    is a schematic flowchart of another charging method according to an embodiment of the present invention; 
         FIG.  7   a    is an example diagram of another prompt according to an embodiment of the present invention; 
         FIG.  7   b    is an example diagram of another prompt according to an embodiment of the present invention; 
         FIG.  8    is a schematic modular diagram of a charge protection apparatus according to an embodiment of the present invention; 
         FIG.  9    is a schematic modular diagram of a user terminal according to an embodiment of the present invention; and 
         FIG.  10    is a schematic structural diagram of a user terminal according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In solutions provided in the present invention, a charging current is monitored in real time, so that a user terminal monitors whether a leakage current exists in a current charging process, and in a case of the leakage current, a power cable is disconnected from charging in time by using a charge protection apparatus, so as to protect the user terminal. To make a person skilled in the art understand the technical solutions in the present invention better, the following clearly describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are merely some rather than all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. 
     In the specification, claims, and accompanying drawings of the present invention, the terms “first”, “second”, “third”, “fourth”, and the like are intended to distinguish between different objects but do not indicate a particular order. Moreover, the terms “include”, “contain”, and any other variant thereof are intended to cover a non-exclusive inclusion. For example, a process, a method, a system, a product, or a device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes an unlisted step or unit, or optionally further includes another inherent step or unit of the process, the method, the product, or the device. 
     “Embodiment” mentioned in this specification indicates that a particular characteristic, structure, or property that is related to the embodiment may be included in at least one embodiment of the present invention. The word occurring at different locations in this specification does not necessarily refer to a same embodiment, or an independent or alternate embodiment exclusive of another embodiment. A person skilled in the art understands, in explicit and implicit manners, that an embodiment described in this specification may be combined with another embodiment. 
     For ease of understanding the present invention, the following first describes an example diagram of existing charging. As shown in  FIG.  1   , to charge a user terminal, there may be a charger, a charging data cable, and the user terminal. In one manner, the charging data cable and the charger may be integrated together. In another manner, one end of the charging data cable and the charger may be connected by using a USB port. The charging data cable has a USB port at the other end of the charging data cable, and is connected to a charging port of the user terminal by using the USB port. In this way, the charging data cable is connected to the user terminal. The charging data cable further includes a charging cable. The charging cable may include a power cable, a data cable, and a ground cable. The data cable may include a positive data cable (Data+, D+) and a negative data cable (Data−, D−). If the charging data cable and the charger are integrated together, when the charger is connected to a power supply apparatus and the USB port at the other end of the charging data cable is connected to the user terminal, a function for charging the user terminal can be implemented. Alternatively, if the charging data cable and the user terminal are connected by using the USB port, a function for charging the user terminal can be implemented in a manner in which one end of the charging data cable is connected to a power supply apparatus, and the other end is connected to the user terminal, instead of using the charger. The power cable is used for charging, and if the power supply apparatus can further exchange data with the user terminal, data transmission can be implemented by using the data cable. 
     However, in an actual application, in a process in which the power supply apparatus charges the user terminal by using the charging data cable, a current flowing through the charging port is short-circuited to ground, and consequently the charging port is burned. In the embodiments of the present invention, a charge protection apparatus is provided. The charge protection apparatus includes a micro control unit (Micro Control Unit, MCU), a current detection circuit, a gating circuit, and an input/output (input/output, I/O) interface. The current detection circuit and the gating circuit are disposed on a power cable. In a charging process, if the gating circuit is in a closed state, the power cable remains in a charging connection; or if the gating circuit is in an open state, the power cable is disconnected from charging. The I/O interface and the data cable are connected, and the MCU sends data by using the I/O interface. The current detection circuit detects an external charging current flowing through the power cable. The current detection circuit transmits the external charging current to the MCU. The MCU transmits the external charging current to a user terminal by using the I/O interface, so that the user terminal calculates a current difference between the external charging current and an internal charging current detected by the user terminal, and determines, based on the current difference, whether to generate a circuit control command. The MCU receives the circuit control command sent by the user terminal, and controls, according to the circuit control command, the gating circuit to be in the closed state or the open state. A charging current is monitored in real time, so that the user terminal monitors whether a leakage current exists in a current charging process, and in a case of the leakage current, the power cable is disconnected from charging in time by using the charge protection apparatus, so as to protect the user terminal. 
     The USB port in the embodiments of the present invention may be a type-A USB port, a type-B USB port, a mini USB port, a micro USB port, or a lightning USB port. For example, if a USB port at one end of a charging data cable is a type-A male USB port, in one manner, the USB port is directly connected to a type-A female USB port of a power supply apparatus; in another manner, the USB port is connected to a type-A USB port disposed in a charger, and the charger is inserted into a power source socket to implement a connection between the USB port and a power source. A USB port at the other end of the charging data cable is a micro male USB port, and may be connected to a micro female USB port: a charging port of a user terminal, to implement a function for charging the user terminal. It may be understood that, although a port used for the charging data cable is a USB port currently, in the embodiments of the present invention, any transmission port for implementing electrical signal transmission and/or data signal transmission can be used for the charging data cable. 
     In the embodiments of the present invention, the user terminal may be any device that needs to be charged by using a charging port, such as a tablet computer, a mobile phone, a personal computer (Personal Computer, PC), a notebook computer, an in-vehicle device, a smart band, a smartwatch, or smart glasses. 
     Referring to  FIG.  2   ,  FIG.  2    is a schematic structural diagram of a charge protection apparatus according to an embodiment of the present invention. As shown in  FIG.  2   , the charge protection apparatus  1  is connected to a charging cable  2 . The charging cable  2  includes a power cable  201  and a data cable  202 . Optionally, the charging cable  2  includes a ground cable  203 . The charge protection apparatus  1  includes a micro control unit  101 , a current detection circuit  102 , a gating circuit  103 , an I/O interface  105 , and a bus  112 . Optionally, the charge protection apparatus  1  further includes a port status detection circuit  104 . Optionally, the charge protection apparatus  1  further includes a voltage detection circuit  106  and/or a temperature detection circuit  107 . Optionally, the charge protection apparatus  1  may further include a prompt circuit  108 , a buzzer  109 , an indicator  110 , and an oscillator  111 . 
     The current detection circuit  102  and the gating circuit  103  are disposed on the power cable  201 . In a charging process, if the gating circuit  103  is in a closed state, the power cable  201  remains in a charging connection; or if the gating circuit  103  is in an open state, the power cable  201  is disconnected from charging. The I/O interface  105  and the data cable  202  are connected. The MCU  101  sends data by using the I/O interface  105 . 
     The bus  112  may include a channel, used to transmit information between the components included in the charge protection apparatus  1 . 
     The current detection circuit  102  detects an external charging current flowing through the power cable  201 . The current detection circuit  102  transmits the external charging current to the MCU  101 . The MCU  101  transmits the external charging current to a user terminal by using the I/O interface  105 , so that the user terminal calculates a current difference between the external charging current and an internal charging current detected by the user terminal, and determines, based on the current difference, whether to generate a circuit control command. Content about this part is described in the following embodiment. The MCU  101  receives the circuit control command sent by the user terminal, and controls, according to the circuit control command, the gating circuit  103  to be in the closed state or the open state. In this way, a charging current of the charge protection apparatus can be monitored in real time, so that the user terminal monitors whether a leakage current exists in the current charging process, and in a case of the leakage current, the power cable is disconnected from charging in time by using the charge protection apparatus, so as to protect the user terminal. 
     If the circuit control command is to keep charging, the MCU  101  controls the gating circuit  103  to be in the closed state, so that the power cable  201  remains in the charging connection; or if the circuit control command is to disconnect from charging, the MCU  101  controls the gating circuit  103  to be in the open state, so that the power cable is disconnected from charging. 
     Optionally, the charge protection apparatus further includes the port status detection circuit  104 . The port status detection circuit  104  and the gating circuit  103  are connected in parallel. When the gating circuit  103  is in the open state, if the port status detection circuit  104  detects that the gating circuit  103  is disconnected from the power supply apparatus or is disconnected from a charging port of the user terminal, the port status detection circuit  104  notifies the MCU  101  that the port connection has been broken, and the MCU  101  controls the gating circuit  103  to be in the closed state. 
     For example, the port status detection circuit  104  may include a current limiting resistor and a micro current detection circuit. Because the port status detection circuit  104  and the gating circuit  103  are connected in parallel, the port status detection circuit is equivalent to another closed circuit on the power cable. However, herein, setting a resistance value of the current limiting resistor can enable a current of the closed circuit to be at a milliampere scale or even smaller, and the current can be detected by using the micro current detection circuit. During specific implementation, if the micro current detection circuit detects a current greater than 0 in the closed circuit, it indicates that the user terminal is not disconnected from the power supply apparatus, and is not disconnected from the charging port of the user terminal, either. In this case, a connected state of the gating circuit  103  is not changed. If the micro current detection circuit detects a current 0 in the closed circuit, it indicates that the gating circuit  103  is disconnected from the power supply apparatus and is also disconnected from the charging port of the user terminal, and it further indicates that the user terminal is currently not charged. Therefore, on this premise, once the gating circuit  103  is in the open state, the port status detection circuit  104  notifies the MCU  101  that the gating circuit  103  is disconnected from the charging port, so that the MCU  101  controls the gating circuit  103  to restore to the closed state, helping the charge protection apparatus perform protection for a next charging connection. 
     For example, the MCU  101  may control, by using a high level signal, the gating circuit  103  to be in the closed state, and control, by using a low level signal, the gating circuit  103  to be in the open state. Specifically, the MCU  101  may send, to the gating circuit  103 , a first digital signal indicating the high level signal, and the gating circuit  103  generates the high level signal through digital-analog conversion after receiving the first digital signal. The high level signal is used to control the gating circuit  103  to be in the closed state. Likewise, the MCU  101  may send, to the gating circuit  103 , a second digital signal indicating the low level signal, and the gating circuit  103  generates the low level signal through digital-analog conversion after receiving the second digital signal. The low level signal is used to control the gating circuit  103  to be in the open state. 
     For another example, referring to  FIG.  3   a   ,  FIG.  3   a    is an example diagram of charging according to an embodiment of the present invention. As shown in  FIG.  3   a   , one end of a charging data cable is connected to a charger, and the other end is connected to a charging port of a user terminal. The charging data cable includes a charge protection apparatus. A charging cable connected to the charge protection apparatus is a cable in the charging data cable. In the user terminal, the charging port is connected to a charging control integrated circuit (integrated circuit, IC), and the charging control IC is connected to a battery of the user terminal. After the charger is connected to a power source, the user terminal can be charged by using the charging data cable. In a charging process, the charging data cable may detect an external charging current by using the charge protection apparatus. The charging control IC of the user terminal can detect an internal charging current of the user terminal. The user terminal compares the external charging current and the internal charging current, to detect whether a leakage current exists. Specifically, if a current difference between the external charging current and the internal charging current is less than a first current threshold (for example, the first current threshold is 5 milliampere or 1 milliampere), it may be considered that the battery of the user terminal is in a normal charging state, and no leakage current exists in the current charging process. If the current difference between the external charging current and the internal charging current is greater than the first current threshold, a leakage current exists in the current charging process. Some of currents flowing from the charging data cable to the charging port of the user terminal may flow into the charging control IC, and some of the currents may flow into a ground cable of the charging port. If there is an extremely high current in the ground cable of the charging port, the charging port may be burned due to overheating. Therefore, in this embodiment of the present invention, the charging data cable may receive a circuit control command that is generated by the user terminal based on a result of comparison between the internal charging current and the external charging current, and further control whether a power cable is disconnected from charging, so as to protect the user terminal. The charge protection apparatus is usually disposed near the port of the user terminal on the charging data cable. 
     For another example, referring to  FIG.  3   b   ,  FIG.  3   b    is another example diagram of charging according to an embodiment of the present invention. One end of a charging data cable is connected to a charger, and the other end is connected to a charging port of a user terminal. The charger includes a charge protection apparatus. The charger has a power cable and a ground cable. Therefore, when the charging data cable is connected to the charger, a power cable of the charging data cable is connected to the power cable of the charger. Then a data cable is disposed in the charger to connect to an I/O interface of the charge protection apparatus. The data cable may be connected to a data cable in the charging data cable when the charging data cable is connected to the charger. In the user terminal, the charging port is connected to a charging control IC, and the charging control IC is connected to a battery of the user terminal. After the charger is connected to a power source, the user terminal can be charged by using the charging data cable. In a charging process, the charging data cable can detect an external charging current by using the charge protection apparatus, and the charging control IC of the user terminal can detect an internal charging current of the user terminal. The user terminal compares the external charging current and the internal charging current, to detect whether a leakage current exists. Therefore, in this embodiment of the present invention, the charger may receive a circuit control command that is generated by the user terminal based on a result of comparison between the internal charging current and the external charging current, and further control whether the power cable is disconnected from charging, so as to protect the user terminal. 
     In a first feasible embodiment, based on the foregoing description, the charge protection apparatus  1  further includes the prompt circuit  108 , the buzzer  109 , the indicator  110 , and the oscillator  111 . During specific implementation, if the circuit control command further includes a first warning prompt, the MCU  101  performs a warning operation according to the first warning prompt by using the prompt circuit  108 . The prompt circuit is configured to control whether the buzzer rings, control whether the indicator flickers, and/or control whether the oscillator oscillates. 
     Optionally, the charge protection apparatus may include one or more of the buzzer  109 , the indicator  110 , and the oscillator  111 . It may be understood that, if the buzzer  109  is included, the first warning prompt may include a prompt mode in which the buzzer  109  rings; if the indicator  110  is included, the first warning prompt may include a prompt mode in which the indicator  110  flickers; or if the oscillator  111  is included, the first warning prompt may include a prompt mode in which the oscillator oscillates. 
     Further, optionally, a first time interval for ringing of the buzzer  109 , a second time interval for flickering of the indicator  110 , and/or a third time interval for oscillation of the oscillator  111  are/is set in the first warning prompt. In this case, that the MCU  101  controls, according to the first warning prompt by using the prompt circuit  108 , the buzzer  109  to ring, controls the indicator  110  to flicker, and/or controls the oscillator  111  to oscillate is specifically: by using the prompt circuit  108 , controlling the buzzer  109  to ring based on the first time interval, controlling the indicator  110  to flicker based on the second time interval, and/or controlling the oscillator  111  to oscillate based on the third time interval. 
     Further, for example, if the charge protection apparatus includes the indicator  110  and the oscillator  111 , the first warning prompt may include only the prompt mode in which the indicator  110  flickers, or include only the prompt mode in which the oscillator  111  oscillates, or include the prompt mode in which the indicator  110  flickers and the prompt mode in which the oscillator  111  oscillates. Therefore, when the first warning prompt may include a plurality of prompt modes, one or more of the prompt modes may be selected for prompting. This is not limited in this embodiment of the present invention. In this way, a user is prompted in the prompt mode, so that the user can learn of a current charging status in time. 
     Optionally, in the example diagram of charging shown in  FIG.  3   a   , the oscillator  111  may not be disposed in the charge protection apparatus  1 , so as to reduce space occupied by the charge protection apparatus  1 . 
     It should be noted that, in this embodiment of the present invention, the buzzer, the indicator, and the oscillator are set based on the time interval, or the buzzer, the indicator, and the oscillator may be set in a manner, for example, by using a timer, or based on a quantity of ringing times/a quantity of flickering times/a quantity of oscillation times, or based on different ringtone content/different indicator colors/different oscillation levels. The setting may be performed by a manufacturer or an end user. This is not limited in this embodiment of the present invention. 
     For example, if the MCU  101  receives the first warning prompt and the circuit control command for keeping charging that are sent by the user terminal, the MCU  101  sends an instruction that the gating circuit  103  is to remain in the closed state to the gating circuit  103 , and sends, to the prompt circuit  108 , an instruction that the buzzer  109  is to ring at intervals of 10s and an instruction that the indicator  110  is to flicker in green at a low speed. If the MCU  101  receives the first warning prompt and the circuit control command for disconnecting from charging that are sent by the user terminal, the MCU  101  sends an instruction that the gating circuit  103  is to switch to the open state to the gating circuit  103 , and sends, to the prompt circuit  108 , an instruction that the buzzer  109  is to constantly ring and an instruction that the indicator  110  is to flicker in red at a high speed. If the MCU  101  has not received the circuit control command sent by the user terminal, the MCU  101  does not send an instruction to the gating circuit  103 , and the buzzer  109  and the indicator  110  may remain in a default state (for example, the default state is a state in which the buzzer  109  does not ring and the indicator  110  does not flicker and is in an off state). 
     In a second feasible embodiment, if the charge protection apparatus  1  does not include the prompt circuit  108 , the buzzer  109 , the indicator  110 , or the oscillator  111 , or if the charge protection apparatus  1  includes the prompt circuit  108 , the buzzer  109 , the indicator  110 , and the oscillator  111 , the charge protection apparatus  1  further includes the temperature detection circuit  107 . The temperature detection circuit  107  is configured to detect a temperature of the charging cable. 
     Specifically, the temperature detection circuit  107  transmits the detected temperature of the charging cable to the user terminal, so that the user terminal determines, based on the temperature of the charging cable, whether to generate the circuit control command. The MCU  101  receives the circuit control command sent by the user terminal, and controls, according to the circuit control command, the gating circuit  103  to be in the closed state or the open state. 
     If the circuit control command is to keep charging, the MCU  101  controls the gating circuit  103  to be in the closed state; or if the circuit control command is to disconnect from charging, the MCU  101  controls the gating circuit  103  to be in the open state. 
     Optionally, in the example diagram of charging shown in  FIG.  3   a   , the charge protection apparatus  1  may be disposed at a position close to a USB port connected to the charging port of the user terminal, so that the temperature detection circuit  107  can more accurately detect a temperature around the charging port, so as to better protect the user terminal. A plurality of temperature detection circuits  107  may be disposed. 
     Optionally, in the example diagram of charging shown in  FIG.  3   b   , a module other than the temperature detection circuit  107  in the charge protection apparatus  1  may be disposed in the charger, and the temperature detection circuit  107  may be independently disposed at a position close to a USB port connected to the charging port of the user terminal on the charging data cable, so that the temperature detection circuit  107  can more accurately detect a temperature around the charging port, so as to better protect the user terminal. 
     Further, if the charge protection apparatus  1  further includes the prompt circuit  108 , the buzzer  109 , the indicator  110 , and the oscillator  111 , the MCU  101  may further receive the circuit control command that carries the first warning prompt and that is sent by the user terminal, and the MCU  101  performs a warning operation according to the first warning prompt by using the prompt circuit  108 . 
     It should be noted that, for the first warning prompt herein, refer to the first warning prompt described in the first feasible embodiment. Details are not described herein again. 
     In a third feasible embodiment, based on the foregoing feasible embodiments, the charge protection apparatus  1  further includes the voltage detection circuit  106 , and the voltage detection circuit  106  is disposed on the power cable. 
     Specifically, the voltage detection circuit  106  detects an external charging voltage of the power cable, and the voltage detection circuit  106  transmits the external charging voltage to the MCU  101 . The MCU  101  transmits the external charging voltage to the user terminal by using the I/O interface  105 , so that the user terminal determines, based on the external charging voltage, whether to generate the circuit control command. The MCU  101  receives the circuit control command sent by the user terminal, and controls, according to the circuit control command, the gating circuit  103  to be in the closed state or the open state. 
     If the circuit control command is to keep charging, the MCU  101  controls the gating circuit  103  to be in the closed state; or if the circuit control command is to disconnect from charging, the MCU  101  controls the gating circuit  103  to be in the open state. 
     In this embodiment of the present invention, the charging current, the charging voltage, and the temperature of the charging cable are monitored in real time, so that the user terminal monitors whether a leakage current exists in the current charging process, whether a charging voltage is extremely high, and whether a temperature is extremely high, and in a case of the leakage current, the extremely high voltage, or the extremely high temperature, the power cable is disconnected in time by using the charge protection apparatus, so as to protect the user terminal. In addition, through triple detection of the charging current, the charging voltage, and the temperature of the charging cable, the user terminal can be better protected in the charging process. 
     Referring to  FIG.  4   ,  FIG.  4    is a schematic flowchart of a charging method according to an embodiment of the present invention. The embodiment shown in  FIG.  4    is described from two perspectives of a charge protection apparatus and a user terminal. For the charge protection apparatus, refer to the charge protection apparatus in the embodiment shown in  FIG.  2   . In the embodiment shown in  FIG.  4   , the charge protection apparatus may be disposed in a charger or a charging data cable. Therefore, the charge protection apparatus is connected to a power supply apparatus by using the charger or the charging data cable. A USB port of the charging data cable is connected to a charging port of the user terminal. The method may include step  101  to step  107 . 
       101 . The charge protection apparatus detects an external charging current flowing through a power cable. 
     Specifically, the charge protection apparatus detects, by using a current detection circuit, the external charging current flowing through the power cable. It may be understood that, in a process of charging the user terminal, a current of the power supply apparatus is transmitted from the charge protection apparatus to the user terminal, and therefore the current first flows through the charge protection apparatus, and then is transmitted to the user terminal. Therefore, in this embodiment of the present invention, the external charging current and an internal charging current may be compared, to determine whether a leakage current exists in the current charging process. 
       102 . The charge protection apparatus sends the external charging current to the user terminal. 
     Specifically, the charge protection apparatus sends the external charging current to the user terminal by using a data cable, and correspondingly, the user terminal receives the external charging current sent by the charge protection apparatus, so that the user terminal monitors the external charging current in the current charging process. 
       103 . The user terminal detects an internal charging current. 
     Optionally, a charging control IC is disposed inside the user terminal, and the charging control IC is configured to detect the internal charging current flowing through a battery of the user terminal. 
     In a feasible solution, the user terminal may determine whether the internal charging current is greater than a fourth current threshold. The fourth current threshold is a maximum charging current that the user terminal can tolerate. If the internal charging current is less than or equal to the fourth current threshold, the user terminal performs step  104 . If the internal charging current is greater than the fourth current threshold, in one solution, the user terminal proceeds to perform step  104 , to detect whether a leakage current exists, and the user terminal performs a current limiting operation by using the charging control IC, so that the internal charging current is reduced to a value less than or equal to the fourth current threshold; in another solution, the user terminal does not perform step  104 , but directly generates a circuit control command for disconnecting from charging, and performs step  106  to send the circuit control command to the charge protection apparatus, so that after the charge protection apparatus receives the circuit control command for disconnecting from charging, the power cable is disconnected by using the charge protection apparatus, so as to protect the user terminal. 
       104 . The user terminal calculates a current difference between the external charging current and the internal charging current. 
     Specifically, the user terminal calculates the current difference between the external charging current detected by the charge protection apparatus and the internal charging current detected by the user terminal. The current difference may be used to detect whether a leakage current exists in the current charging process. If no leakage current exists, the current difference between the external charging current and the internal charging current is less than a first current threshold (for example, the first current threshold is 5 milliampere or 1 milliampere). If the current difference between the external charging current and the internal charging current is greater than the first current threshold, it indicates that a leakage current exists in the current charging process. 
       105 . The user terminal determines, based on the current difference, whether to generate a circuit control command. 
     Specifically, if the current difference is greater than the first current threshold and less than a second current threshold, the user terminal determines that the generated circuit control command is to keep charging; or if the current difference is greater than the second current threshold and less than a third current threshold, the user terminal determines that the generated circuit control command is to disconnect from charging. It may be understood that, if the current difference is less than the first current threshold, the user terminal does not generate the circuit control command. The first current threshold, the second current threshold, and the third current threshold are real numbers greater than or equal to 0. 
     It should be noted that, in this embodiment of the present invention, based on the first current threshold, the second current threshold, and the third current threshold, there are three cases about whether to generate the circuit control command. Cases in which the current difference is equal to the first current threshold, the second current threshold, and the third current threshold may be respectively added to classifications in which the first current threshold, the second current threshold, and the third current threshold are respectively used as critical values, and a case in which the current difference is equal to one threshold cannot be added to different classifications. For example, the case in which the current difference is equal to the second current threshold may be added to a solution in which if the current difference is greater than the first current threshold and less than or equal to the second current threshold, it is determined that the generated circuit control command is to keep charging; or the case in which the current difference is equal to the second current threshold may be added to a solution in which if the current difference is greater than or equal to the second current threshold and less than the third current threshold, it is determined that the generated circuit control command is to disconnect from charging. 
     Optionally, if the current difference is greater than the first current threshold and less than the second current threshold, the user terminal outputs a first pop-up prompt on a screen. The first pop-up prompt is a prompt message used to indicate that the current difference exists in the current charging process. For example, referring to  FIG.  5   a   ,  FIG.  5   a    is an example diagram of a prompt according to an embodiment of the present invention. As shown in  FIG.  5   a   , if the current difference is greater than the first current threshold and less than the second current threshold, it indicates that a leakage current with a relatively small current exists in the current charging process, and a warning notice shown in  FIG.  5   a    may be used to notify a user. The warning notice can be used to instruct the user to check whether there is a problem of liquid intake, corrosion, or the like for the charging port of the user terminal, so as to protect the charging port from being burned. 
     If the current difference is greater than the second current threshold and less than the third current threshold, the user terminal outputs a second pop-up prompt on the screen. The second pop-up prompt is a prompt message used to indicate that the current difference exists in the current charging process and charging is disconnected. For example, referring to  FIG.  5   b   ,  FIG.  5   b    is another example diagram of a prompt according to an embodiment of the present invention. As shown in  FIG.  5   b   , if the current difference is greater than the second current threshold and less than the third current threshold, it indicates that a leakage current with a relatively large current exists in the current charging process, and a warning notice shown in  FIG.  5   b    may be used to notify a user. The warning notice can be used to notify the user that charging is disconnected and instruct the user to check in time whether there is a problem of liquid intake, corrosion, or the like for the charging port of the user terminal. 
       106 . The user terminal sends the circuit control command to the charge protection apparatus. 
     Specifically, the user terminal sends the circuit control command to the charge protection apparatus by using the data cable. 
     Correspondingly, the charge protection apparatus receives the circuit control command sent by the user terminal. It may be understood that, if the circuit control command sent by the user terminal is not received, the charge protection apparatus remains in a charging state, and in this case, the power cable remains in a charging connection. 
       107 . The charge protection apparatus controls, according to the circuit control command, whether the power cable is disconnected from charging. 
     Specifically, in the process of charging the user terminal, if the received circuit control command is to keep charging, the charge protection apparatus controls the power cable to remain in the charging connection; or if the received circuit control command is to disconnect from charging, the charge protection apparatus controls the power cable to disconnect from charging. The charge protection apparatus may control a gating circuit to remain in a closed state, so that the power cable remains in the charging connection; or the charge protection apparatus may control the gating circuit to switch to an open state, so that the power cable is disconnected from charging. 
     In a feasible solution, if the circuit control command carries a first warning prompt, the charge protection apparatus performs a warning operation according to the first warning prompt. Optionally, the first warning prompt carries at least one prompt mode and a time interval for executing each prompt mode, and therefore the charge protection apparatus performs, based on the time interval for each prompt mode, an operation corresponding to each prompt mode. Optionally, in this embodiment of the present invention, the prompt mode may include but is not limited to at least one of a mode in which a buzzer rings, a mode in which an indicator flickers, and a mode in which an oscillator oscillates. It should be noted that, in this embodiment of the present invention, the buzzer, the indicator, and the oscillator are set based on the time interval, or the buzzer, the indicator, and the oscillator may be set in a manner, for example, by using a timer, or based on a quantity of ringing times/a quantity of flickering times/a quantity of oscillation times, or based on different ringtone content/different indicator colors/different oscillation levels. The setting may be performed by a manufacturer or an end user. This is not limited in this embodiment of the present invention. 
     In this embodiment of the present invention, a charging current is monitored in real time, so that the user terminal monitors whether a leakage current exists in the current charging process, and in a case of the leakage current, the power cable is disconnected in time by using the charge protection apparatus, so as to protect the user terminal. 
     Referring to  FIG.  6   ,  FIG.  6    is a schematic flowchart of a charging method according to an embodiment of the present invention. The embodiment shown in  FIG.  6    is described from two perspectives of a charge protection apparatus and a user terminal. For the charge protection apparatus, refer to the charge protection apparatus in the embodiment shown in  FIG.  2   . In the embodiment shown in  FIG.  6   , the charge protection apparatus may be disposed in a charger or a charging data cable. Therefore, the charge protection apparatus is connected to a power supply apparatus by using the charger or the charging data cable. A USB port of the charging data cable is connected to a charging port of the user terminal. The method may include step  201  to step  213 . 
       201 . The charge protection apparatus detects an external charging current flowing through a power cable. 
     Specifically, the charge protection apparatus detects, by using a current detection circuit, the external charging current flowing through the power cable. It may be understood that, in a process of charging the user terminal, a current of the power supply apparatus is transmitted from the charge protection apparatus to the user terminal, and therefore the current first flows through the charge protection apparatus, and then is transmitted to the user terminal. Therefore, in this embodiment of the present invention, the external charging current and an internal charging current may be compared, to determine whether a leakage current exists in the current charging process. 
       202 . The charge protection apparatus sends the external charging current to the user terminal. 
     Specifically, the charge protection apparatus sends the external charging current to the user terminal by using a data cable, and correspondingly, the user terminal receives the external charging current sent by the charge protection apparatus, so that the user terminal learns of the external charging current in the current charging process. 
       203 . The user terminal detects an internal charging current. 
     Optionally, a charging control IC is disposed inside the user terminal, and the charging control IC is configured to detect the internal charging current flowing through a battery of the user terminal. 
       204 . The user terminal calculates a current difference between the external charging current and the internal charging current. 
       205 . The user terminal determines, based on the current difference, whether to generate a circuit control command. 
       206 . The charge protection apparatus receives the circuit control command sent by the user terminal. 
       207 . The charge protection apparatus controls, according to the circuit control command, whether the power cable is disconnected from charging. 
     For step  203  to step  207 , refer to detailed descriptions of corresponding steps in the embodiment shown in  FIG.  4   . Details are not described herein again. 
       208 . The charge protection apparatus detects a temperature of a charging cable. 
     Specifically, the charge protection apparatus detects the temperature of the charging cable by using a built-in temperature detection circuit. In the process of charging the user terminal, an extremely high temperature at the charging port may cause the charging port and the charge protection apparatus to be burned. Therefore, if the temperature detection circuit is at a position close to the USB port connected to the charging port of the user terminal, the temperature detection circuit can more accurately detect a temperature around the charging port, thereby improving detection accuracy. 
     Optionally, the charge protection apparatus may detect the external charging current and the temperature of the charging cable concurrently, and therefore step  201  and step  208  are performed in no particular order. 
       209 . The charge protection apparatus sends the temperature of the charging cable to the user terminal. 
     Specifically, the charge protection apparatus sends the temperature of the charging cable to the user terminal by using the data cable, and correspondingly, the user terminal receives the temperature of the charging cable that is sent by the charge protection apparatus, so that the user terminal learns of the temperature of the charging cable in the current charging process. 
       210 . The user terminal determines, based on the temperature of the charging cable, whether to generate the circuit control command. 
     Specifically, if the temperature of the charging cable is greater than a first temperature threshold and less than a second temperature threshold, the user terminal determines that the generated circuit control command is to keep charging; or if the temperature of the charging cable is greater than the second temperature threshold, the user terminal determines that the generated circuit control command is to disconnect from charging. It may be understood that, if the temperature of the charging cable is less than the first temperature threshold, the user terminal does not generate the circuit control command. The first temperature threshold, the second temperature threshold, and a third temperature threshold are real numbers greater than or equal to 0. 
     It should be noted that, in this embodiment of the present invention, based on the first temperature threshold, the second temperature threshold, and the third temperature threshold, there are three cases about whether to generate the circuit control command. Cases in which the temperature of the charging cable is equal to the first temperature threshold, the second temperature threshold, and the third temperature threshold may be respectively added to classifications in which the first temperature threshold, the second temperature threshold, and the third temperature threshold are respectively used as critical values, and a case in which the temperature of the charging cable is equal to one threshold cannot be added to different classifications. For example, the case in which the temperature of the charging cable is equal to the second temperature threshold may be added to a solution in which if the temperature of the charging cable is greater than the first temperature threshold and less than or equal to the second temperature threshold, it is determined that the generated circuit control command is to keep charging; or the case in which the temperature of the charging cable is equal to the second temperature threshold may be added to a solution in which if the temperature of the charging cable is greater than or equal to the second temperature threshold and less than the third temperature threshold, it is determined that the generated circuit control command is to disconnect from charging. 
     Optionally, if the temperature of the charging cable is greater than the first temperature threshold and less than the second temperature threshold, the user terminal outputs a third pop-up prompt on a screen. The third pop-up prompt is a prompt message used to indicate that the temperature of the charging cable is extremely high in the current charging process. For example, referring to  FIG.  7   a   ,  FIG.  7   a    is another example diagram of a prompt according to an embodiment of the present invention. As shown in  FIG.  7   a   , if the temperature of the charging cable is greater than the first temperature threshold and less than the second temperature threshold, it indicates that continuous heating may occur due to a short circuit in the current charging process, and a warning notice shown in  FIG.  7   a    may be used to notify a user. The warning notice can be used to instruct the user to check whether there is any exception in a connection between a second USB port of the charge protection apparatus and the charging port of the user terminal, so as to protect the charging port from being burned due to continuous heating. 
     If the temperature of the charging cable is greater than the second temperature threshold and less than the third temperature threshold, the user terminal outputs a fourth pop-up prompt on the screen. The fourth pop-up prompt is a prompt message used to indicate that the temperature of the charging cable is extremely high in the current charging process and charging is disconnected. For example, referring to  FIG.  7   b   ,  FIG.  7   b    is another example diagram of a prompt according to an embodiment of the present invention. As shown in  FIG.  7   b   , if the temperature of the charging cable is greater than the second temperature threshold and less than the third temperature threshold, it indicates that a temperature is extremely high in the current charging process, and a warning notice shown in  FIG.  7   b    may be used to notify a user. The warning notice can be used to notify the user that charging is disconnected and instruct the user to check in time whether there is any exception in a connection between a second USB port of the charge protection apparatus and the charging port of the user terminal. 
     After step  210 , if the user terminal determines to generate the circuit control command, the following steps are performed: step  206  of sending the circuit control command to the charge protection apparatus and step  207  of controlling, according to the circuit control command, whether the power cable is disconnected from charging. For details, refer to detailed descriptions of corresponding steps in the embodiment shown in  FIG.  4   . Details are not described herein again. 
       211 . The charge protection apparatus detects an external charging voltage of the power cable. 
     Specifically, the charge protection apparatus detects the external charging voltage of the power cable by using a built-in voltage detection circuit. 
     Optionally, the charge protection apparatus may detect the external charging current, the temperature of the charging cable, and the external charging voltage of the power cable concurrently, and therefore step  201 , step  208 , and step  211  are performed in no particular order. 
       212 . The charge protection apparatus sends the external charging voltage to the user terminal. 
     Specifically, the charge protection apparatus sends the external charging voltage to the user terminal by using the data cable, and correspondingly, the user terminal receives the external charging voltage sent by the charge protection apparatus, so that the user terminal learns of the external charging voltage in the current charging process. 
       213 . The user terminal determines, based on the external charging voltage of the power cable, whether to generate the circuit control command. 
     Specifically, if the external charging voltage of the power cable is greater than a first voltage threshold and less than a second voltage threshold, the user terminal determines that the generated circuit control command is to keep charging; or if the external charging voltage of the power cable is greater than the second voltage threshold, the user terminal determines that the generated circuit control command is to disconnect from charging. It may be understood that, if the external charging voltage of the power cable is less than the first voltage threshold, the user terminal does not generate the circuit control command. The first voltage threshold, the second voltage threshold, and a third voltage threshold are real numbers greater than or equal to 0. 
     It should be noted that, in this embodiment of the present invention, based on the first voltage threshold, the second voltage threshold, and the third voltage threshold, there are three cases about whether to generate the circuit control command. Cases in which the external charging voltage of the power cable is equal to the first voltage threshold, the second voltage threshold, and the third voltage threshold may be respectively added to classifications in which the first voltage threshold, the second voltage threshold, and the third voltage threshold are respectively used as critical values, and a case in which the external charging voltage of the power cable is equal to one threshold cannot be added to different classifications. For example, the case in which the external charging voltage of the power cable is equal to the second voltage threshold may be added to a solution in which if the external charging voltage of the power cable is greater than the first voltage threshold and less than or equal to the second voltage threshold, it is determined that the generated circuit control command is to keep charging; or the case in which the external charging voltage of the power cable is equal to the second voltage threshold may be added to a solution in which if the external charging voltage of the power cable is greater than or equal to the second voltage threshold and less than the third voltage threshold, it is determined that the generated circuit control command is to disconnect from charging. 
     Optionally, if the external charging voltage of the power cable is greater than the first voltage threshold and less than the second voltage threshold, the user terminal outputs a fifth pop-up prompt on the screen. The fifth pop-up prompt is a prompt message used to indicate that the external charging voltage of the power cable is extremely high in the current charging process. For example, if the external charging voltage of the power cable is greater than the first voltage threshold and less than the second voltage threshold, it indicates that a charging voltage is extremely high in the current charging process, and a warning notice may be used to notify a user. The warning notice can be used to notify the user that currently the charging voltage is extremely high, and the user may determine whether the user terminal keeps charging. 
     If the external charging voltage of the power cable is greater than the second voltage threshold and less than the third voltage threshold, the user terminal outputs a sixth pop-up prompt on the screen. The sixth pop-up prompt is a prompt message used to indicate that the external charging voltage of the power cable is extremely high in the current charging process and charging is disconnected. For example, if the external charging voltage of the power cable is greater than the second voltage threshold and less than the third voltage threshold, it indicates that a voltage is extremely high in the current charging process, and a warning notice may be used to notify a user. The warning notice can be used to notify the user that charging is disconnected and the charging voltage is extremely high. 
     After step  213 , if the user terminal determines to generate the circuit control command, the following steps are performed: step  206  of sending the circuit control command to the charge protection apparatus and step  207  of controlling, according to the circuit control command, whether the power cable is disconnected from charging. For details, refer to detailed descriptions of corresponding steps in the embodiment shown in  FIG.  4   . Details are not described herein again. 
     Optionally, the user terminal may further output the internal charging current and the external charging current on the screen. 
     Optionally, the user terminal may further output the temperature of the charging cable on the screen. 
     Optionally, the user terminal may further output the external charging voltage on the screen. 
     It should be noted that, in this embodiment of the present invention, step  208  and step  209  are performed if the temperature detection circuit is built in the charge protection apparatus. Therefore, provided that the charge protection apparatus includes the temperature detection circuit, the solution of step  208  and step  209  may be executed. If a leakage current exists at the charging port and the charging port remains in a charging state for a long time, the charging cable in the charge protection apparatus continuously emits heat. A probability that the charge protection apparatus is burned can be reduced by detecting the temperature of the charging cable. Further, if the temperature detection circuit is at the position close to the USB port connected to the charging port of the user terminal, the temperature detection circuit can more accurately detect the temperature around the charging port, thereby improving detection accuracy. 
     It should also be noted that, in this embodiment of the present invention, step  211  and step  212  are performed if the voltage detection circuit is built in the charge protection apparatus. Therefore, provided that the temperature detection circuit is built in the charge protection apparatus, step  211  and step  212  may be performed. 
     Optionally, when the power cable is disconnected from charging, if it is detected that the power cable is disconnected from the power supply apparatus or is disconnected from the charging port of the user terminal, the charge protection apparatus controls the power cable to establish a charging connection. In this way, after the power cable is disconnected from charging, when the charge protection apparatus is not used to charge the user terminal, the power cable is restored to a charging connection state, so that the charge protection apparatus performs protection for a next charging connection. 
     Optionally, when the user terminal generates the circuit control command, the user terminal performs a warning operation based on a preset second warning prompt. The second warning prompt includes at least one prompt mode. For example, the prompt mode may include one or more of a sound prompt mode, a flicker prompt mode, and an oscillation prompt mode, and the prompt mode in the second warning prompt is not limited to these prompt modes. The circuit control command may be a command for keeping charging or disconnecting from charging, and therefore the user terminal may set different prompt modes for different commands. In this way, the user is prompted in the prompt mode, so that the user can learn of a current charging status in time. 
     For example, if the circuit control command is to keep charging, the user terminal may provide a sound prompt by using a first ringtone. For another example, if the circuit control command is to disconnect from charging, the user terminal may provide a sound prompt by using a second ringtone and provide an oscillation prompt. 
     In this embodiment of the present invention, the charging current, the charging voltage, and the temperature of the charging cable are monitored in real time, so that the user terminal monitors whether a leakage current exists in the current charging process, whether a charging voltage is extremely high, and whether a temperature is extremely high, and in a case of the leakage current, the extremely high voltage, or the extremely high temperature, the power cable is disconnected in time by using the charge protection apparatus, so as to protect the user terminal. In addition, through triple detection of the charging current, the charging voltage, and the temperature of the charging cable, the user terminal can be better protected in the charging process. 
     Referring to  FIG.  8   ,  FIG.  8    is a schematic modular diagram of a charge protection apparatus according to an embodiment of the present invention. As shown in  FIG.  8   , the charge protection apparatus  1  in this embodiment of the present invention may include a detection unit  11 , a sending unit  12 , a receiving unit  13 , and a control unit  14 . 
     The control unit  14  is configured to detect an external charging current of a power cable by using the detection unit  11 ; 
     the control unit  14  is further configured to send the external charging current to a user terminal by using the sending unit  12 , so that the user terminal calculates a current difference between the external charging current and an internal charging current detected by the user terminal, and determines, based on the current difference, whether to generate a circuit control command; 
     the control unit  14  is further configured to receive, by using the receiving unit  13 , the circuit control command sent by the user terminal; and the control unit  14  is further configured to control, according to the circuit control command, whether the power cable is disconnected from charging. 
     In a possible embodiment, the control unit  14  is further configured to: detect a temperature of a charging cable by using the detection unit  11 , and send the temperature of the charging cable to the user terminal, so that the user terminal determines, based on the temperature of the charging cable, whether to generate the circuit control command. 
     In a possible embodiment, the control unit  14  is further configured to: detect an external charging voltage of the power cable by using the detection unit  11 , and send the external charging voltage to the user terminal, so that the user terminal determines, based on the external charging voltage, whether to generate the circuit control command. 
     In a possible embodiment, with regard to the controlling, according to the circuit control command, whether the power cable is disconnected from charging, the control unit  14  is specifically configured to: 
     if the circuit control command is to keep charging, control the power cable to remain in a charging connection; or if the circuit control command is to disconnect from charging, control the power cable to disconnect from charging. 
     In a possible embodiment, the control unit  14  is further configured to: if a first warning prompt is set in the circuit control command, perform a warning operation according to the first warning prompt. 
     In a possible embodiment, at least one prompt mode and a time interval for executing each prompt mode are set in the first warning prompt; and the control unit  14  is specifically configured to: if the first warning prompt is set in the circuit control command, perform, based on the time interval for each prompt mode, an operation corresponding to each prompt mode. 
     In a possible embodiment, the control unit  14  is further configured to: when the power cable is disconnected from charging, if it is detected that the power cable is disconnected from the power supply apparatus or is disconnected from a charging port of the user terminal, control the power cable to establish a charging connection. 
     It should be noted that, functions and beneficial effects of functional units of the charge protection apparatus  1  described in this embodiment of the present invention may be specifically described according to the method in the method embodiment shown in  FIG.  4    or  FIG.  5   . Details are not described herein again. 
     In this embodiment, the charge protection apparatus  1  is presented in a form of a functional unit. The “unit” herein may be an application-specific integrated circuit (application-specific integrated circuit, ASIC), a circuit, a processor executing one or more software or firmware programs, an integrated logic circuit, and/or another component capable of providing the foregoing functions. In a simple embodiment, a person skilled in the art may figure out that the form shown in  FIG.  2    may be used for the charge protection apparatus  1 . 
     An embodiment of the present invention further provides a computer storage medium, configured to store a computer software instruction used by the charge protection apparatus  1  shown in  FIG.  8   . The computer software instruction includes a program designed for the charge protection apparatus  1  to execute the foregoing methods. 
     Referring to  FIG.  9   ,  FIG.  9    is a schematic modular diagram of a user terminal  2  according to an embodiment of the present invention. As shown in  FIG.  9   , the user terminal  2  in this embodiment of the present invention may include a detection unit  21 , a receiving unit  22 , a processing unit  23 , and a sending unit  24 . Optionally, the user terminal  2  may further include a first output unit  25 , a second output unit  26 , a third output unit  27 , and/or a fourth output unit  28 . 
     The processing unit  23  is configured to detect an internal charging current by using the detection unit  21 ; 
     the processing unit  23  is further configured to receive, by using the receiving unit  22 , an external charging current sent by the charge protection apparatus; 
     the processing unit  23  is further configured to calculate a current difference between the external charging current and the internal charging current; 
     the processing unit  23  is further configured to determine, based on the current difference, whether to generate a circuit control command; and the processing unit  23  is further configured to: if the circuit control command is generated, send the circuit control command to the charge protection apparatus by using the sending unit  24 . 
     In a possible embodiment, with regard to the determining, based on the current difference, whether to generate a circuit control command, the processing unit  23  is specifically configured to: 
     if the current difference is greater than a first current threshold and less than a second current threshold, determine that the generated circuit control command is to keep charging; or if the current difference is greater than the second current threshold and less than a third current threshold, determine that the generated circuit control command is to disconnect from charging. 
     In a possible embodiment, the user terminal  2  further includes the first output unit  25 ; 
     the processing unit  23  is further configured to: if the current difference is greater than the first current threshold and less than the second current threshold, output a first pop-up prompt on a screen by using the first output unit  25 , where the first pop-up prompt is a prompt message used to indicate that the current difference exists in a current charging process; and 
     the processing unit  23  is further configured to: if the current difference is greater than the second current threshold and less than the third current threshold, output a second pop-up prompt on the screen by using the first output unit  25 , where the second pop-up prompt is a prompt message used to indicate that the current difference exists in the current charging process and charging is disconnected. 
     In a possible embodiment, the processing unit  23  is further configured to receive, by using the receiving unit  22 , a temperature of a charging cable that is sent by the charge protection apparatus; and 
     the processing unit  23  is further configured to determine, based on the temperature of the charging cable, whether to generate the circuit control command. 
     In a possible embodiment, with regard to the determining, based on the temperature of the charging cable, whether to generate the circuit control command, the processing unit  23  is specifically configured to: 
     if the temperature of the charging cable is greater than a first temperature threshold and less than a second temperature threshold, determine that the generated circuit control command is to keep charging; or if the temperature of the charging cable is greater than the second temperature threshold, determine that the generated circuit control command is to disconnect from charging. 
     In a possible embodiment, the user terminal  2  further includes the second output unit  26 ; 
     the processing unit  23  is further configured to: if the temperature of the charging cable is greater than the first temperature threshold and less than the second temperature threshold, output a third pop-up prompt on the screen by using the second output unit  26 , where the third pop-up prompt is a prompt message used to indicate that the temperature of the charging cable is extremely high in the current charging process; and 
     the processing unit  23  is further configured to: if the temperature of the charging cable is greater than the second temperature threshold and less than the third temperature threshold, output a fourth pop-up prompt on the screen by using the second output unit  26 , where the fourth pop-up prompt is a prompt message used to indicate that the temperature of the charging cable is extremely high in the current charging process and charging is disconnected. 
     In a possible embodiment, the processing unit  23  is further configured to receive, by using the receiving unit  22 , an external charging voltage sent by the charge protection apparatus; and 
     the processing unit  23  is further configured to determine, based on the external charging voltage, whether to generate the circuit control command. 
     In a possible embodiment, with regard to the determining, based on the external charging voltage, whether to generate the circuit control command, the processing unit  23  is specifically configured to: 
     if the external charging voltage is greater than a first voltage threshold and less than a second voltage threshold, determine that the generated circuit control command is to keep charging; or if the external charging voltage is greater than the second voltage threshold, determine that the generated circuit control command is to disconnect from charging. 
     In a possible embodiment, the user terminal  2  further includes the third output unit  27 ; 
     the processing unit  23  is further configured to: if the external charging voltage is greater than the first voltage threshold and less than the second voltage threshold, output a fifth pop-up prompt on the screen by using the third output unit  27 , where the fifth pop-up prompt is a prompt message used to indicate that the external charging voltage is extremely high in the current charging process; and 
     the processing unit  23  is further configured to: if the external charging voltage is greater than the second voltage threshold and less than the third voltage threshold, output a sixth pop-up prompt on the screen by using the third output unit  27 , where the sixth pop-up prompt is a prompt message used to indicate that the external charging voltage is extremely high in the current charging process and charging is disconnected. 
     In a possible embodiment, the user terminal  2  further includes the fourth output unit  28 ; and 
     the processing unit  23  is further configured to output the internal charging current, the external charging current, and the external charging voltage on the screen by using the fourth output unit  28 . 
     In a possible embodiment, a first warning prompt is set in the circuit control command, and the first warning prompt is used to instruct the charge protection apparatus to perform a warning operation according to the first warning prompt. 
     In a possible embodiment, at least one prompt mode and a time interval for executing each prompt mode are set in the first warning prompt. 
     In a possible embodiment, the processing unit  23  is further configured to perform a warning operation based on a preset second warning prompt if the circuit control command is generated, where the second warning prompt includes at least one prompt mode. 
     It should be noted that, functions and beneficial effects of functional units of the user terminal  2  described in this embodiment of the present invention may be specifically described according to the method in the method embodiment shown in  FIG.  4    or  FIG.  5   . Details are not described herein again. 
     In this embodiment, the user terminal  2  is presented in a form of a functional unit. The “unit” herein may be an application-specific integrated circuit (application-specific integrated circuit, ASIC), a circuit, a processor executing one or more software or firmware programs, an integrated logic circuit, and/or another component capable of providing the foregoing functions. In a simple embodiment, a person skilled in the art may figure out that a user terminal shown in  FIG.  10    may be used for the user terminal in the embodiment shown in  FIG.  9   . As shown in  FIG.  10   ,  FIG.  10    is a schematic structural diagram of a user terminal according to an embodiment of the present invention. The user terminal  2000  includes at least one processor  2001 , a bus  2002 , a transceiver  2004 , and a charging control IC  2005 . 
     The processor  2001  and the transceiver  2004  are connected, for example, by using the bus  2002 . Optionally, the user terminal  2000  may further include a memory  2003 , the memory  2003  is configured to store data of the user terminal  2000  or store application program code used to execute the solutions of the present invention, and the processor  2001  is configured to control the execution. The processor  2001  is configured to execute the application program code stored in the memory  2003 , to implement an action of the user terminal in the embodiment shown in  FIG.  4    or  FIG.  5   . 
     Further, optionally, the user terminal  2000  may further include an audio frequency system  2006 , an oscillator  2007 , and/or a display system  2008 . The audio frequency system  2006  is configured to output an audio frequency signal. The oscillator  2007  is configured to perform an oscillation operation. The display system  2008  is configured to output and display information and receive an operation input by a user. 
     It should be noted that, a quantity of transceivers  2004  is not limited in an actual application, and the user terminal  2000  does not impose a limitation on the embodiments of the present invention. 
     The processor  2001  in this embodiment of the present invention is configured to implement a function of the processing unit  23  shown in  FIG.  9   . The transceiver  2004  includes a receiver and a transmitter. The transceiver  2004  in this embodiment of the present invention is configured to implement functions of the receiving unit  22  and the sending unit  24  shown in  FIG.  9   . The charging control IC in this embodiment of the present invention is configured to implement a function of the detection unit  21  shown in  FIG.  9   . The display system  2008  in this embodiment of the present invention is configured to implement functions of the first output unit  25 , the second output unit  26 , the third output unit  27 , and/or the fourth output unit  28  shown in  FIG.  9   . The audio frequency system  2006  and the oscillator  2007  are configured to output a plurality of prompt modes in the second warning prompt executed by the processor  2001 . 
     The processor  2001  may be a central processing unit (Central Processing Unit, CPU), a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application-specific integrated circuit (Application-Specific Integrated Circuit, ASIC), a field-programmable gate array (Field-Programmable Gate Array, FPGA) or another programmable logic device, a transistor logic device, a hardware device, or any combination thereof. The processor  2001  may implement or execute various example logical blocks, modules, and circuits described with reference to content disclosed in the present invention. Alternatively, the processor  2001  may be a combination for implementing a computing function, for example, a combination including one or more microprocessors, a combination of a DSP and a microprocessor, or the like. 
     The bus  2002  may include a channel, used to transmit information between the foregoing components. The bus  2002  may be a Peripheral Component Interconnect (Peripheral Component Interconnect, PCI) bus, an extended industry standard architecture (Extended Industry Standard Architecture, EISA) bus, or the like. The bus  2002  may be classified into an address bus, a data bus, a control bus, and the like. For ease of representation, the bus is represented by using only one bold line in  FIG.  10   . However, this does not mean that there is only one bus or one type of bus. 
     The memory  2003  may be a read-only memory (read-only memory, ROM) or another type of static storage device capable of storing static information and instructions, a random access memory (random access memory, RAM) or another type of dynamic storage device capable of storing information and instructions, or may be an electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, EEPROM), a compact disc read-only memory (Compact Disc Read-Only Memory, CD-ROM) or another compact disc storage, an optical disc storage (including a compressed optical disc, a laser disc, an optical disc, a digital universal optical disc, a Blu-ray disc, and the like), a magnetic disk storage medium or another magnetic storage device, or any other medium capable of carrying or storing expected program code in a form of instructions or data structures and capable of being accessed by a computer. However, this is not limited herein. 
     An embodiment of the present invention further provides a computer storage medium, configured to store a computer software instruction used by the user terminal, and the computer software instruction includes a program designed for the user terminal to execute the foregoing methods. 
     It should be noted that, for ease of description, the foregoing method embodiments are represented as a series of actions. However, a person skilled in the art should appreciate that the present invention is not limited to the described order of the actions, because according to the present invention, some steps may be performed in other orders or simultaneously. In addition, a person skilled in the art should also appreciate that all the embodiments described in this specification are example embodiments, and the related actions and modules are not necessarily mandatory to the present invention. 
     In the foregoing embodiments, the descriptions of the embodiments have respective focuses. For a part that is not described in detail in an embodiment, refer to related descriptions in other embodiments. 
     A sequence of the steps of the method in the embodiments of the present invention may be adjusted, and steps may also be merged or removed as actually required. 
     Merging, division, and removing may be performed on the units in the apparatus in the embodiments of the present invention as actually required. A person skilled in the art may combine different embodiments and features of different embodiments described in this specification. 
     With descriptions of the foregoing embodiments, a person skilled in the art may clearly understand that the present invention may be implemented by hardware, firmware, or a combination thereof. When the present invention is implemented by software, the foregoing functions may be stored in a computer-readable medium or transmitted as one or more instructions or code in the computer-readable medium. The computer-readable medium includes a computer storage medium and a communications medium, where the communications medium includes any medium that enables a computer program to be transmitted from one place to another. The storage medium may be any available medium accessible to a computer. The computer-readable medium may include but is not limited to: a random access memory (Random Access Memory, RAM), a read-only memory (Read-Only Memory, ROM), an electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, EEPROM), a compact disc read-only memory (Compact Disc Read-Only Memory, CD-ROM) or another optical disk storage, a disk storage medium or another disk storage, or any other medium capable of carrying or storing expected program code in a form of instructions or data structures and capable of being accessed by a computer. In addition, any connection may be appropriately defined as a computer-readable medium. For example, if software is transmitted from a website, a server, or another remote source by using a coaxial cable, an optical fiber/cable, a twisted pair, a digital subscriber line (Digital Subscriber Line, DSL) or wireless technologies such as infrared ray, radio, and microwave, the coaxial cable, optical fiber/cable, twisted pair, DSL or wireless technologies such as infrared ray, radio, and microwave are included in definitions of a medium to which they belong. For example, a disk (Disk) and a disc (disc) used by the present invention include a compact disc (CD), a laser disc, an optical disc, a digital versatile disc (DVD), a floppy disk, and a Blu-ray disc, where the disk generally copies data by a magnetic means, and the disc copies data optically by a laser means. The foregoing combination should also be included in the protection scope of the computer-readable medium. 
     In conclusion, what is described above is merely example embodiments of the technical solutions of the present invention, but is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of the present invention shall fall within the protection scope of the present invention.