Abstract:
A power adapter, a tenninal, and a method for processing an impedance anomaly in a charging circuit. The terminal ( 10 ) forms a charging circuit with the power adapter through a charging interface ( 12 ), so as to charge a battery ( 11 ). The terminal ( 10 ) also comprises a communications unit ( 13 ), a detection unit ( 14 ), and an anomaly processing unit ( 15 ). The communications unit ( 13 ) is used for receiving voltage indication information from the power adapter when the power adapter charges the terminal, the voltage indication information indicating the output voltage of the power adapter. The detection unit ( 14 ) is used for detecting the input voltage of the power adapter. The anomaly processing unit ( 15 ) is used for determining, on the basis of any difference between input and output voltages, whether charging circuit impedance is anomalous, and for controlling the charging circuit to enter a protected state when such an anomaly is found. Detecting and processing charging circuit anomalies improves the safety of the charging process.

Description:
TECHNICAL FIELD 
       [0001]    Embodiments of the present disclosure relate to the charging technical field, and more particularly, to a power adapter, a terminal and a method for processing an impedance anomaly of a charging loop. 
       BACKGROUND 
       [0002]    Currently, batteries in most of electronic devices are coupled to external power adapters via charging interfaces of the electronic devices to be charged. 
         [0003]    Phenomenon of an impedance anomaly of a charging loop often occurs during charging. There are various reasons resulting in the impedance anomaly, for example, a poor contact caused by not well inserting the charging interface, and a poor contact between a battery and a connector at each terminal of the battery due to dirt at the two terminals of the battery. 
         [0004]    In a case that the impedance anomaly of the charging loop occurs, if the charging goes on, charging components (such as a battery, a power adapter, and a terminal) will be damaged, so that there are security risks. In the related art, the impedance anomaly of the charging loop cannot be detected and processed, so that the security during charging is poor. 
       SUMMARY 
       [0005]    Embodiments of the present disclosure provide a power adapter, a terminal and a method for processing an impedance anomaly of a charging loop, so as to improve the security during charging. 
         [0006]    In a first aspect, a terminal is provided. The terminal includes a battery and a charging interface, and is configured to form a charging loop with a power adapter via the charging interface to charge the battery. The terminal further includes: a communication unit, configured to receive voltage indication information from the power adapter when the power adapter charges the terminal, in which the voltage indication information indicates an output voltage of the power adapter; a detection unit, configured to detect an input voltage of the power adapter; and an anomaly processing unit, configured to determine whether an impedance of the charging loop is abnormal according to a difference between the input voltage and the output voltage, and to control the charging loop to enter into a protected state if the impedance of the charging loop is abnormal. 
         [0007]    Combined with the first aspect, in an implementation of the first aspect, the anomaly processing unit is configured to determine whether the impedance of the charging loop is abnormal according to the difference between the input voltage and the output voltage and to control the charging loop to enter into the protected state if the impedance of the charging loop is abnormal, and specifically: to determine a level of the impedance according to the difference; to control the charging loop to enter into a protected state corresponding to the level, according to the level of the impedance. 
         [0008]    Combined with any one of the first aspect or the above implementation, in another implementation of the first aspect, detection positions of the input voltage of the power adapter and the output voltage of the power adapter are located at two terminals of the charging interface respectively, and the impedance of the charging loop specifically refers to an impedance of a circuit in the charging interface. 
         [0009]    Combined with any one of the first aspect or the above implementations, in another implementation of the first aspect, a detection position of the input voltage of the power adapter is located at two terminals of the battery of the terminal, and the impedance of the charging loop specifically refers to an impedance of a circuit from the power adapter to the battery of the terminal. 
         [0010]    Combined with any one of the first aspect or the above implementations, in another implementation of the first aspect, the terminal further includes: an alarm device, configured to generate an alarm signal if the impedance of the charging loop is abnormal. 
         [0011]    Combined with any one of the first aspect or the above implementations, in another implementation of the first aspect, the communication unit is configured to send charging protection indication information to the power adapter if the impedance of the charging loop is abnormal, so as to instruct the power adapter to control the charging loop to enter into the protected state. 
         [0012]    Combined with any one of the first aspect or the above implementations, in another implementation of the first aspect, the charging interface includes a power wire and a data wire, the terminal is configured to form the charging loop with the power adapter via the charging interface to charge the battery, and specifically: to form the charging loop with the power adapter via the power wire in the charging interface to charge the battery; the communication unit is configured to receive the voltage indication information from the power adapter, and specifically: to receive the voltage indication information from the power adapter via the data wire in the charging interface. 
         [0013]    In a second aspect, a power adapter is provided. The power adapter includes a power conversion unit and a charging interface, and the power conversion unit is configured to form a charging loop with a terminal via the charging interface to charge a battery of the terminal. The power adapter further includes: a detection unit, a communication unit and an anomaly processing unit, in which, the detection unit is configured to detect an output voltage of the power adapter when the power adapter charges the terminal; the communication unit is configured to send voltage indication information to the terminal, the voltage indication information indicating the output voltage of the power adapter detected by the detection unit; the communication unit is configured to receive charging protection indication information from the terminal if the terminal determines that an impedance of the charging loop is abnormal based on a difference between an input voltage of the power adapter and the output voltage of the power adapter; and the anomaly processing unit is configured to control the charging loop to enter into a protected state according to an indication of the charging protection indication information. 
         [0014]    Combined with the second aspect, in an implementation of the second aspect, the charging interface includes a power wire and a data wire, the power conversion unit is configured to form the charging loop with the terminal via the charging interface to charge the battery of the terminal, and specifically: to form the charging loop with the terminal via the power wire in the charging interface to charge the battery of the terminal; the communication unit is configured to send the voltage indication information to the terminal, and specifically: to send the voltage indication information to the terminal via the data wire in the charging interface. 
         [0015]    Combined with any one of the second aspect or the above implementation, in another implementation of the second aspect, detection positions of the input voltage of the power adapter and the output voltage of the power adapter are located at two terminals of the charging interface respectively, and the impedance of the charging loop specifically refers to an impedance of a circuit in the charging interface. 
         [0016]    Combined with any one of the second aspect or the above implementations, in another implementation of the second aspect, a detection position of the input voltage of the power adapter is located at two terminals of the battery of the terminal, and the impedance of the charging loop specifically refers to an impedance of a circuit from the power adapter to the battery of the terminal. 
         [0017]    Combined with any one of the second aspect or the above implementations, in another implementation of the second aspect, the power adapter further includes: an alarm device, configured to generate an alarm signal if the impedance of the charging loop is abnormal. 
         [0018]    In a third aspect, a method for processing an impedance anomaly of a charging loop is provided. The method includes: receiving, by a terminal, voltage indication information from a power adapter when the power adapter charges the terminal, the voltage indication information indicating an output voltage of the power adapter; detecting, by a terminal, an input voltage of the power adapter; and determining, by a terminal, whether an impedance of the charging loop is abnormal according to a difference between the input voltage and the output voltage and controlling, by the terminal, the charging loop to enter into a protected state if the impedance of the charging loop is abnormal. 
         [0019]    Combined with the third aspect, in an implementation of the third aspect, determining, by the terminal, whether the impedance of the charging loop is abnormal according to the difference between the input voltage and the output voltage and controlling, by the terminal, the charging loop to enter into the protected state if the impedance of the charging loop is abnormal, includes: determining, by the terminal, a level of the impedance according to the difference; and controlling, by the terminal, the charging loop to enter into a protected state corresponding to the level according to the level of the impedance. 
         [0020]    Combined with any one of the third aspect or the above implementations, in another implementation of the third aspect, detection positions of the input voltage of the power adapter and the output voltage of the power adapter are located at two terminals of a charging interface respectively, and the impedance of the charging loop specifically refers to an impedance of a circuit in the charging interface. 
         [0021]    Combined with any one of the third aspect or the above implementations, in another implementation of the third aspect, a detection position of the input voltage of the power adapter is located at two terminals of a battery of the terminal, and the impedance of the charging loop specifically refers to an impedance of a circuit from the power adapter to the battery of the terminal. 
         [0022]    Combined with any one of the third aspect or the above implementations, in another implementation of the third aspect, the method further includes: generating, by the terminal, an alarm signal if the impedance of the charging loop is abnormal. 
         [0023]    Combined with any one of the third aspect or the above implementations, in another implementation of the third aspect, the method further includes: sending, by the terminal, charging protection indication information to the power adapter if the impedance of the charging loop is abnormal, so as to instruct the power adapter to control the charging loop to enter into the protected state. 
         [0024]    Combined with any one of the third aspect or the above implementations, in another implementation of the third aspect, the charging interface includes a power wire and a data wire, the power adapter charges the terminal via the power wire, receiving, by the terminal, the voltage indication information from the power adapter includes: receiving, by the terminal, the voltage indication information from the power adapter via the data wire in the charging interface. 
         [0025]    In a fourth aspect, a method for processing an impedance anomaly of a charging loop is provided. The method includes: detecting, by the power adapter, an output voltage of the power adapter when the power adapter charges the terminal; sending, by the power adapter, voltage indication information to the terminal, the voltage indication information indicating the output voltage of the power adapter detected by the power adapter; receiving, by the power adapter, charging protection indication information from the terminal if the terminal determines that an impedance of the charging loop is abnormal based on a difference between an input voltage of the power adapter and the output voltage of the power adapter; and controlling, by the power adapter, the charging loop to enter into a protected state according to an indication of the charging protection indication information. 
         [0026]    Combined with the fourth aspect, in an implementation of the fourth aspect, a charging interface includes a power wire and a data wire, the power adapter charges the terminal via the power wire in the charging interface, sending by the power adapter the voltage indication information to the terminal, includes: sending, by the power adapter, the voltage indication information to the terminal via the data wire in the charging interface. 
         [0027]    Combined with any one of the fourth aspect or the above implementations, in another implementation of the fourth aspect, detection positions of the input voltage of the power adapter and the output voltage of the power adapter are located at two terminals of the charging interface respectively, and the impedance of the charging loop specifically refers to an impedance of a circuit in the charging interface. 
         [0028]    Combined with any one of the fourth aspect or the above implementations, in another implementation of the fourth aspect, a detection position of the input voltage of the power adapter is located at two terminals of a battery of the terminal, and the impedance of the charging loop specifically refers to an impedance of a circuit from the power adapter to the battery of the terminal. 
         [0029]    Combined with any one of the fourth aspect or the above implementations, in another implementation of the fourth aspect, the method further includes: generating an alarm signal if the impedance of the charging loop is abnormal. 
         [0030]    In embodiments of the present disclosure, the terminal obtains the output voltage of the power adapter via the communication with the power adapter. The terminal determines whether the impedance of the charging loop is abnormal according to the difference between the output voltage of the power adapter and the input voltage of the power adapter detected by itself, and controls the charging loop to enter into the protected state if the impedance of the charging loop is abnormal, thereby improving the security during charging. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    In order to make the technical solutions of embodiments of the present disclosure more clearly, the accompanying drawings used in the description of embodiments of the present disclosure are briefly described hereunder. Obviously, the described drawings are merely some embodiments of present disclosure. For persons skilled in the art, other drawings may be obtained based on these drawings without any creative work. 
           [0032]      FIG. 1  is a schematic block diagram showing a terminal according to an embodiment of the present disclosure; 
           [0033]      FIG. 2  is a schematic block diagram showing a power adapter according to an embodiment of the present disclosure; 
           [0034]      FIG. 3  is a schematic flow chart showing a method for processing an impedance anomaly of a charging loop according to an embodiment of the present disclosure; 
           [0035]      FIG. 4  is a schematic flow chart showing a method for processing an impedance anomaly of a charging loop according to an embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    The technical solutions in embodiments of the present disclosure are hereinafter described clearly and completely with reference to the accompanying drawings in embodiments of the present disclosure. It should be understood that, embodiments described herein are a part of embodiments of the present disclosure, but not all. Based on embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of the present disclosure. 
         [0037]      FIG. 1  is a schematic block diagram showing a terminal according to an embodiment of the present disclosure. The terminal  10  in  FIG. 1  includes a battery  11  and a charging interface  12 . The terminal  10  forms a charging loop with a power adapter via the charging interface  12  to charge the battery  11 . The terminal  10  further includes: a communication unit  13 , a detection unit  14  and an anomaly processing unit  15 . 
         [0038]    The communication unit  13  is configured to receive voltage indication information from the power adapter when the power adapter charges the terminal, in which the voltage indication information indicates an output voltage of the power adapter detected by the terminal. 
         [0039]    The detection unit  14  is configured to detect an input voltage of the power adapter. 
         [0040]    The anomaly processing unit  15  is configured to determine whether an impedance of the charging loop is abnormal according to a difference between the input voltage and the output voltage, and to control the charging loop to enter into a protected state if the impedance of the charging loop is abnormal. 
         [0041]    In embodiments of the present disclosure, the terminal obtains the output voltage of the power adapter via the communication with the power adapter. The terminal determines whether the impedance of the charging loop is abnormal according to the difference between the output voltage of the power adapter and the input voltage of the power adapter detected by itself, and controls the charging loop to enter into the protected state if the impedance of the charging loop is abnormal, thereby improving the security during charging. 
         [0042]    It should be understood that, the anomaly processing unit  15  is configured to control the charging loop to enter into the protected state may include, and specifically: to reduce the input voltage of the power adapter; to reduce an input current of the power adapter; or to switch off the charging loop. 
         [0043]    Alternatively, as an embodiment, the anomaly processing unit  15  is configured to determine whether the impedance of the charging loop is abnormal according to the difference between the input voltage and the output voltage and to control the charging loop to enter into the protected state if the impedance of the charging loop is abnormal, and specifically: to determine a level of the impedance according to the difference between the input voltage and the output voltage of the power adapter; and to control the charging loop to enter into a protected state corresponding to the level according to the level of the impedance. 
         [0044]    For example, a correspondence between a level of the impedance and a difference between the input voltage and the output voltage of the power adapter may be set in advance. After the anomaly processing unit  15  determines an actual difference between the input voltage of the power adapter and the output voltage of the power adapter, a level of the impedance corresponding to the actual difference may be found by using the above correspondence. Different levels of the impedance correspond to different protected states respectively. For example, the levels of the impedance include “light”, “medium” and “heavy”. If the level of the impedance is “light”, it can control the charging loop to continue charging with a large current; if the level of the impedance is “medium”, it can control the charging loop to charge with a small current; and if the level of the impedance is “heavy”, it can control the charging loop to be switched off. 
         [0045]    It should be noted that, a position where the output voltage of the power adapter is detected and a position where the input voltage of the power adapter is detected by the terminal are not be limited specifically in embodiments of the present disclosure, and can be set according to different requirements. 
         [0046]    For example, detection positions of the input voltage of the power adapter and the output voltage of the power adapter are located at two terminals of the charging interface respectively, and the impedance of the charging loop specifically refers to an impedance of a circuit in the charging interface. The above detection positions of the input voltage of the power adapter and the output voltage of the power adapter being located respectively at two terminals of the charging interface specifically refers to that, the position where the power adapter detects the output voltage and the position where the terminal detects the input voltage of the power adapter are close to the charging interface coupled to the power adapter and the terminal. If any of the power adapter and the terminal detects that a drop of voltage is abnormal, it may be determined that it is caused by an impedance anomaly of the circuit in the charging interface. 
         [0047]    For another example, a detection position of the input voltage of the power adapter is located at two terminals of the battery, and the impedance of the charging loop specifically refers to an impedance of a circuit from the power adapter to the battery of the terminal. Since the input current of the power adapter flows through each component within the terminal and reaches the two terminals of the battery eventually, the difference between the input voltage and the output voltage of the power adapter can indicate the impedance of the whole charging loop if the terminal detects the input voltage of the power adapter at the two terminals of the battery. 
         [0048]    Alternatively, as an embodiment, the terminal  10  further includes an alarm device configured to generate an alarm signal if the impedance of the charging loop is abnormal. The alarm device can be a sound alarm device, or a lamp. Taking the impedance of the charging loop being the impedance of the circuit in the charging interface as an example, when the alarm device raises an alarm, it indicates that the charging interface contacts poorly and reminds a user to re-couple the charging interface between the power adapter and the terminal. 
         [0049]    Alternatively, as an embodiment, the communication unit  13  sends charging protection indication information to the power adapter if the impedance of the charging loop is abnormal, so as to instruct the power adapter to control the charging loop to enter into the protected state. 
         [0050]    In embodiments of the present disclosure, if the impedance of the charging loop is abnormal, the terminal not only controls the charging loop to enter into the protected state actively, but also instructs the power adapter to control the charging loop to enter into the protected state. In this way, even if the anomaly processing unit of the terminal is invalid and cannot control the charging loop to enter into the protected state, the charging loop still can be controlled by the power adapter to enter into the protected state, thereby further improving the security during charging. 
         [0051]    Alternatively, as an embodiment, the charging interface  12  includes a power wire and a data wire. The terminal  10  is configured to form the charging loop with the power adapter via the charging interface  12  to charge the battery, and specifically: to form the charging loop with the power adapter via the power wire in the charging interface  12  to charge the battery  11 ; the communication unit  13  is configured to receive the voltage indication information from the terminal when the power adapter  10  charges the terminal, and specifically: to receive the voltage indication information from the power adapter via the data wire in the charging interface  12 . 
         [0052]    For example, the charging interface may be a Universal Serial Bus (USB) interface or a micro USB interface. The above power wire may be a power wire in the USB interface, for example, +5V power wire and −5V power wire; the above data wire may be a data wire in the USB interface, for example, D+ wire and D− wire. 
         [0053]      FIG. 2  is a schematic block diagram showing a power adapter according to an embodiment of the present disclosure. The power adapter  20  in  FIG. 2  includes a power conversion unit  21  and a charging interface  22 . The power conversion unit  21  is configured to form a charging loop with a terminal via the charging interface  22  to charge a battery of the terminal. The power adapter  20  further includes: a detection unit  23 , a communication unit  24  and an anomaly processing unit  25 . 
         [0054]    The detection unit  23  is configured to detect an output voltage of the power adapter when the power adapter  20  charges the terminal. 
         [0055]    The communication unit  24  is configured to send voltage indication information to the terminal, in which the voltage indication information indicates the output voltage of the power adapter detected by the detection unit  23 . 
         [0056]    The communication unit  24  is configured to receive charging protection indication information from the terminal if the terminal determines that an impedance of the charging loop is abnormal based on a difference between an input voltage of the power adapter  20  and the output voltage of the power adapter  20 . 
         [0057]    The anomaly processing unit  25  is configured to control the charging loop to enter into a protected state according to an indication of the charging protection indication information. 
         [0058]    In embodiments of the present disclosure, the power adapter communicates with the terminal during charging, and sends the output voltage of the power adapter detected by itself to the terminal, so that the terminal determines whether the impendence of the charging loop is abnormal according to the difference between the output voltage of the power adapter and the input voltage of the power adapter detected by itself. If the impendence of the charging loop is abnormal, the power adapter receives the charging protection indication information from the terminal and then controls the charging loop to enter into the protected state, thereby improving the security during charging. 
         [0059]    Alternatively, as an embodiment, the charging interface  22  includes a power wire and a data wire. The power conversion unit  21  is configured to form the charging loop with the terminal via the charging interface  22  to charge the battery of the terminal, and specifically: to form the charging loop with the terminal via the power wire in the charging interface  22  to charge the battery of the terminal; the communication unit  24  is configured to send the voltage indication information to the terminal, and specifically: to send the voltage indication information to the terminal via the data wire in the charging interface  22 . 
         [0060]    For example, the charging interface may be a Universal Serial Bus (USB) interface or a micro USB interface. The above power wire may be a power wire in the USB interface, for example, +5V power wire and −5V power wire; the above data wire may be a data wire in the USB interface, for example, D+ wire and D− wire. 
         [0061]    It should be noted that, a position where the power adapter detects the output voltage thereof and a position where the terminal detects the input voltage of the power adapter are not be limited specifically in embodiments of the present disclosure, and may be set according to different requirements. 
         [0062]    For example, detection positions of the input voltage of the power adapter and the output voltage of the power adapter are located at two terminals of the charging interface respectively, and the impedance of the charging loop specifically refers to an impedance of a circuit in the charging interface. The above detection positions of the input voltage of the power adapter and the output voltage of the power adapter being located respectively at two terminals of the charging interface specifically refers to that, the position where the power adapter detects the output voltage and the position where the terminal detects the input voltage of the power adapter are close to the charging interface coupled to the power adapter and the terminal. If any of the power adapter and the terminal detects that a drop of voltage is abnormal, it may be determined that it is caused by an impedance anomaly of the circuit in the charging interface. 
         [0063]    For another example, a detection position of the input voltage of the power adapter is located at two terminals of the battery, and the impedance of the charging loop specifically refers to an impedance of a circuit from the power adapter to the battery of the terminal. Since the input current of the power adapter flows through each component within the terminal and reaches the two terminals of the battery eventually, the difference between the input voltage and the output voltage of the power adapter may indicate whether the impedance of the whole charging loop is abnormal, if the terminal detects the input voltage of the power adapter at the two terminals of the battery. 
         [0064]    Alternatively, as an embodiment, the power adapter  20  further includes an alarm device configured to generate an alarm signal if the impedance of the charging loop is abnormal. The alarm device can be a sound alarm device, or a lamp. Taking the impedance of the charging loop being the impedance of the circuit in the charging interface as an example, when the alarm device raises an alarm, it indicates that the charging interface has a poor contact and reminds a user to re-couple the charging interface between the power adapter and the terminal. 
         [0065]      FIG. 3  is a schematic flow chart showing a method for processing an impedance anomaly of a charging loop according to an embodiment of the present disclosure. It should be understood that, the method in  FIG. 3  may be performed by the terminal shown in  FIG. 1 , which is not described in detail here to avoid duplication. The method in  FIG. 3  includes followings. 
         [0066]    In block  310 , a terminal receives voltage indication information from a power adapter when the power adapter charges the terminal, in which the voltage indication information indicates an output voltage of the power adapter. 
         [0067]    In block  320 , the terminal detects an input voltage of the power adapter. 
         [0068]    In block  330 , the terminal determines whether an impedance of the charging loop is abnormal according to a difference between the input voltage and the output voltage and controls the charging loop to enter into a protected state if the impedance of the charging loop is abnormal. 
         [0069]    In embodiments of the present disclosure, the terminal obtains the output voltage of the power adapter via the communication with the power adapter. The terminal determines whether the impedance of the charging loop is abnormal according to the difference between the output voltage of the power adapter and the input voltage of the power adapter detected by itself, and controls the charging loop to enter into the protected state if the impedance of the charging loop is abnormal, thereby improving the security during charging. 
         [0070]    Alternatively, as an embodiment, the terminal determining whether the impedance of the charging loop is abnormal according to the difference between the input voltage and the output voltage and controlling the charging loop to enter into the protected state if the impedance of the charging loop is abnormal includes: the terminal determining a level of the impedance according to the difference; and the terminal controlling the charging loop to enter into a protected state corresponding to the level according to the level of the impedance. 
         [0071]    Alternatively, as an embodiment, detection positions of the input voltage of the power adapter and the output voltage of the power adapter are located at two terminals of a charging interface respectively, and the impedance of the charging loop specifically refers to an impedance of a circuit in the charging interface. 
         [0072]    Alternatively, as an embodiment, a detection position of the input voltage of the power adapter is located at two terminals of a battery of the terminal, and the impedance of the charging loop specifically refers to an impedance of a circuit from the power adapter to the battery of the terminal. 
         [0073]    Alternatively, as an embodiment, the method in  FIG. 3  further includes: generating by the terminal an alarm signal if the impedance of the charging loop is abnormal. 
         [0074]    Alternatively, as an embodiment, the method in  FIG. 3  further includes: sending by the terminal charging protection indication information to the power adapter if the impedance of the charging loop is abnormal, so as to instruct the power adapter to control the charging loop to enter into the protected state. 
         [0075]    Alternatively, as an embodiment, the charging interface includes a power wire and a data wire, the power adapter charges the terminal via the power wire, the terminal receiving the voltage indication information from the power adapter includes: the terminal receiving the voltage indication information from the power adapter via the data wire in the charging interface. 
         [0076]      FIG. 4  is a schematic flow chart showing a method for processing an impedance anomaly of a charging loop according to an embodiment of the present disclosure. It should be understood that, the method in  FIG. 4  may be performed by the power adapter shown in  FIG. 2 , which is not described in detail here to avoid duplication. The method in  FIG. 4  includes followings. 
         [0077]    In block  410 , the power adapter detects an output voltage of the power adapter when the power adapter charges the terminal. 
         [0078]    In block  420 , the power adapter sends voltage indication information to the terminal, in which the voltage indication information indicates the output voltage of the power adapter detected by the power adapter. 
         [0079]    In block  430 , the power adapter receives charging protection indication information from the terminal if the terminal determines that an impedance of the charging loop is abnormal based on a difference between an input voltage of the power adapter and the output voltage of the power adapter. 
         [0080]    In block  440 , the power adapter controls the charging loop to enter into a protected state according to an indication of the charging protection indication information. 
         [0081]    In embodiments of the present disclosure, the power adapter communicates with the terminal during charging, and sends the output voltage of the power adapter detected by itself to the terminal, so that the terminal determines whether the impendence of the charging loop is abnormal according to the difference between the output voltage of the power adapter and the input voltage of the power adapter detected by itself. If the impendence of the charging loop is abnormal, the power adapter receives the charging protection indication information from the terminal and then controls the charging loop to enter into the protected state, thereby improving the security during charging. 
         [0082]    Alternatively, as an embodiment, the charging interface includes a power wire and a data wire, and the power adapter charges the terminal via the power wire in the charging interface; the power adapter sending the voltage indication information to the terminal includes: the power adapter sending the voltage indication information to the terminal via the data wire in the charging interface. 
         [0083]    Alternatively, as an embodiment, detection positions of the input voltage of the power adapter and the output voltage of the power adapter are located at two terminals of the charging interface respectively, and the impedance of the charging loop specifically refers to an impedance of a circuit in the charging interface. 
         [0084]    Alternatively, as an embodiment, a detection position of the input voltage of the power adapter is located at two terminals of a battery of the terminal, and the impedance of the charging loop specifically refers to an impedance of a circuit from the power adapter to the battery of the terminal. 
         [0085]    Alternatively, as an embodiment, the method in  FIG. 4  further includes: generating an alarm signal if the impedance of the charging loop is abnormal. 
         [0086]    Those skilled in the art may be aware that, in combination with the examples described in the embodiments disclosed in this specification, units and algorithm steps can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are executed by hardware or software depends on particular applications and design constraint conditions of the technical solutions. Persons skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of the present invention. 
         [0087]    It would be appreciated by those skilled in the art that, for the purpose of simplification convenience of description, concerning the specific working process of the above system, device and unit as described above, reference is made to the method embodiments of the present disclosure, which will not be elaborated herein. 
         [0088]    In several embodiments provided in the application, it should be understood that the disclosed system, device and method can be realized by other manners. For example, the above-described embodiments are only exemplary; for example, the division of said unit is only a logic function division; there may be additional dividing manners during the actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features can be ignored, or not implemented. Another point, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection of devices or units via some interfaces, in electronic, mechanical, or other forms. 
         [0089]    Said unit described as a separation part may be or may not be separated physically; the part displayed as a unit may be or may not be a physical unit, namely it can be located in one place, or can be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment. 
         [0090]    In addition, all functional units in the embodiments of the invention can be integrated in one processing unit, or each unit exists individually in physical form, or two or more units are integrated in one unit. 
         [0091]    If said function is realized in the form of software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. With such an understanding, the technical solution of the invention substantially or its portion that contributes to the prior art or a portion of the technical solution may embody in the form of a computer software product which is stored in a memory media, including a plurality of instructions such that a computer (may be a personal computer, a server, or a network device, etc.) executes all or some steps of the methods described in each of all the embodiments. And the previously mentioned memory media include such media capable of storing program codes as USB flash disk, portable hard drive, read-only memory (ROM), random access memory (RAM), floppy disk or compact disk. 
         [0092]    The above descriptions are only specific embodiments of the invention, but not intended to limit the protection scope of the invention. The variation or replacement easily thought of by those of skill in the art within the technical scope disclosed by the invention, shall fall within the protection scope of the invention. Therefore, the protection scope of the invention shall be determined with reference to the protection scope of the claims.