TWI497284B - Method of controlling surface temperature and related surface temperature control system - Google Patents

Description

Method for controlling surface temperature and related surface temperature control system

The present invention is directed to a method of controlling surface temperature and related surface temperature control systems, and more particularly to a method of controlling surface temperature that satisfies surface low temperature burn standards and associated surface temperature control systems.

At present, consumer electronic products, such as mobile phones, have already supported 3G networks such as Wideband Code Division (W-CDMA). Because the working mode is different, the mobile phone talks under the W-CDMA network for a long time, the temperature of the mobile phone surface will be significantly higher than that of the Global System for Mobile (GSM) network call, and the trend of the mobile phone is also The thinner the phone, the hotter temperature on the surface of the phone has been increasingly valued by the public, so the major mobile phone manufacturers will compare the heating temperature. Some system operators have proposed the standard of low-temperature burns. In the case of whether the mobile phone is charging and the antenna signal strength is weak (the signal is weak, the RF power will increase), it is necessary to ensure that the highest temperature point on the surface of the mobile phone cannot exceed 43 degrees and 8 hours, 45 degrees. 2 hours, 48 degrees and 10 minutes, however, to meet this requirement has the following difficulties:

1. Cost considerations. Adding an additional temperature sensor to detect the temperature of the surface may increase the cost. In addition, even if there is temperature detection inside the mobile phone, the control of the surface temperature of the mobile phone cannot be satisfied. Some mobile phone manufacturers have suggested that the battery temperature should be turned off if it is too high, but the internal battery temperature is not necessarily the hottest point on the surface.

2. Charging will affect the temperature of the surface of the mobile phone, especially the stacking structure of the current smart phone. Since the charging current has reached more than 1 amp, the heat of the battery will directly reflect the surface glass of the mobile phone, and the heat of the power management chip is also Will be higher, it will also affect the surface temperature of the phone.

3. The RF power of W-CDMA will directly affect the heat output of the power amplifier. When the signal is good, the RF power is about 15dbm. When the signal is very poor, the RF power is about 23dbm. Under different powers, the current can vary by several hundred micro. Accompany. The energy loss of the efficiency of the RF power amplifier can be converted to thermal energy, which is directly reflected to the surface glass of the mobile phone.

4. Even if the relationship between internal temperature detection and surface temperature corresponds, how to cover different combinations of RF power and whether it is charging.

5. How to meet the surface temperature duration requirements, but also to meet the battery specifications of the battery can not be charged more than 45 degrees.

Accordingly, it is a primary object of the present invention to provide a method for controlling surface temperature in a mobile device to meet a low temperature burn standard.

A method for controlling surface temperature in a mobile device is disclosed. The method includes periodically reporting a power amplifier temperature digit value and a battery temperature; and when the battery temperature is greater than or equal to a first threshold value and the power amplifier temperature digit value is less than or equal to a second threshold value, and the mobile device is charging Restricting a charging current; determining whether a first timer exists if the battery temperature is greater than or equal to the first threshold and the power amplifier temperature digital value is less than or equal to a third threshold; When present, determining whether the first timer expires; when the first timer has not expired, determining whether the battery temperature is greater than or equal to a fourth threshold and the power amplifier temperature digit value is less than or equal to a fifth Threshold value; determining whether a second timer exists if the battery temperature is greater than or equal to the fourth threshold and the power amplifier temperature digit value is less than or equal to the fifth threshold; and determining whether the second timer already exists Whether the second timer expires; when the second timer has not expired, determining whether the battery temperature is greater than The sixth threshold is 且 and the power amplifier temperature digit value is less than or equal to a seventh threshold; and when the battery temperature is greater than or equal to the sixth threshold and the power amplifier temperature digit value is less than or equal to the seventh threshold, the The call function of the mobile device and an overheating prompt is displayed.

The invention further discloses a surface temperature control system for a mobile device. The surface The temperature control system includes a battery including a first thermistor and a power amplifier module, and a second thermistor coupled to the power amplifier module and a power management chip for detecting the first heat. The temperature of the varistor and the temperature of the second thermistor and a processor are used to perform a surface temperature control method. The surface temperature control method includes periodically reporting a power amplifier temperature digital value and a battery temperature; and when the battery temperature is greater than or equal to a first threshold and the power amplifier temperature digital value is less than or equal to a second threshold value and the When the mobile device is charging, limiting a charging current; determining whether a first timer exists if the battery temperature is greater than or equal to the first threshold and the power amplifier temperature digital value is less than or equal to a third threshold; When a timer already exists, determining whether the first timer expires; when the first timer has not expired, determining whether the battery temperature is greater than or equal to a fourth threshold and the power amplifier temperature digit value is less than Is equal to a fifth threshold value; when the battery temperature is greater than or equal to the fourth threshold value and the power amplifier temperature digital value is less than or equal to the fifth threshold value, determining whether a second timer exists; When present, determining whether the second timer expires; when the second timer has not expired, determining whether The battery temperature is greater than or equal to the sixth threshold value and the power amplifier temperature digital value is less than or equal to a seventh threshold value; and the battery temperature is greater than or equal to the sixth threshold value and the power amplifier temperature digital value is less than or equal to the seventh threshold value When the mobile device's call function is turned off and an overheating prompt is displayed.

10, 20‧‧‧ Process

Steps of 100, 102, 104, 106, 108, 110‧‧

112, 114, 116, 118, 120, 122‧‧‧ steps

124, 126, 128, 130, 132, 134‧ ‧ steps

200, 202, 204, 206, 208, 210‧ ‧ steps

212, 214, 216, 218, 220‧ ‧ steps

70‧‧‧Surface temperature control system

700‧‧‧Battery

720‧‧‧Power Amplifier Module

740‧‧‧Power Management Chip

760‧‧‧ processor

R1, R2‧‧‧ thermistor

TH1, TH2, TH3, TH4, TH5, TH6, TH7‧‧‧ threshold

I‧‧‧Charging current

B_T‧‧‧Battery temperature

PA_AD‧‧‧Power amplifier temperature digital value

FIG. 1 is a schematic diagram of a software flow according to Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram of a process for obtaining one of a plurality of threshold values in the first figure according to an embodiment of the present invention.

Figures 3-6 are actual test results of an embodiment of the present invention.

Figure 7 is a schematic view of a surface temperature control system according to an embodiment of the present invention.

Please refer to FIG. 1 , which is a schematic diagram of a process 10 according to an embodiment of the present invention. The process 10 is used in a mobile device to control the surface temperature of the mobile device. Process 10 includes:

Step 100: Report a power amplifier temperature digital value PA_AD and a battery temperature B_T every minute.

Step 102: Determine whether the battery temperature B_T≧ threshold TH TH1 and the power amplifier temperature digital value PA_AD ≦ a threshold TH2 and the mobile device is charging? If yes, go to step 106; if no, go to step 104.

Step 104: Determine if the mobile device is charging? If yes, go to step 108; if no, go to step 110.

Step 106: Limit a charging current I.

Step 108: Restore the charging current I to a corresponding charging current using USB/ADP charging.

Step 110: Determine whether the battery temperature B_T threshold value TH1 and the power amplifier temperature digital value PA_AD ≦ a threshold value TH3? If yes, go to step 114; if no, go to step 112.

Step 112: Clear a timer A and return to step 100.

Step 114: Determine whether the timer A exists? If yes, go to step 118; if no, go to step 116.

Step 116: Set timer A and execute step 114.

Step 118: Determine whether the timer A is full of time? If yes, go to step 122; if no, go to step 120.

Step 120: Determine whether the battery temperature B_T threshold TH4 and the power amplifier temperature digital value PA_AD ≦ a threshold TH5? If yes, go to step 126; if no, go to step 124.

Step 122: Turn off the call function of the mobile device and display an overheating prompt.

Step 124: Clear a timer B and return to step 100.

Step 126: Determine whether the timer B exists? If yes, go to step 130; if no, go to step 128.

Step 128: Set timer B, and execute step 126.

Step 130: Determine whether the timer B is full of time? If yes, go to step 122; If no, go to step 132.

Step 132: Determine whether the battery temperature B_T threshold TH6 and the power amplifier temperature digital value PA_AD ≦ a threshold TH7? If yes, go to step 134; if no, go to step 100.

Step 134: Clear timer A and timer B.

According to the process 10, the mobile device reports the power amplifier temperature digital value PA_AD and the battery temperature B_T every minute. The battery temperature B_T can be directly read through a software, and the power amplifier temperature digital value PA_AD is a temperature near a power amplifier module, and the power amplifier temperature digital value PA_AD can be detected by an 8-bit analog digital converter. It ranges from 0 to 255, and the smaller the value, the higher the temperature. When the battery temperature B_T is greater than or equal to the threshold TH1 and the power amplifier temperature digit value PA_AD is less than or equal to the threshold TH2 and the mobile device is charging, the charging current is limited to 200 mA to avoid the charging current being too high to cause the battery to generate high heat. When the battery temperature B_T is greater than or equal to the threshold TH1 and the power amplifier temperature digit value PA_AD is less than or equal to the threshold TH3, it is determined whether the timer A is present, and if not, the timer A is set to a period of 6 hours. If the timer A already exists but has not been completed for 6 hours, it is judged whether the battery temperature B_T is greater than or equal to the threshold TH4 and the power amplifier temperature digit value PA_AD is less than or equal to the threshold TH5. If the timer A expires, the call function of the mobile device is turned off. When the battery temperature B_T is greater than or equal to the threshold TH4 and the power amplifier temperature digit value PA_AD is less than or equal to the threshold TH5, it is determined whether the timer B exists, and if not, the timer B is set to have a counting period of one hour. If the timer B already exists but has not been completed for one hour, it is judged whether the battery temperature B_T is greater than or equal to the threshold TH6 and the power amplifier temperature digit value PA_AD is less than or equal to the threshold TH7. If the timer B expires, the call function of the mobile device is turned off. When the battery temperature B_T is greater than or equal to the threshold TH6 and the power amplifier temperature digital value PA_AD is less than or equal to the threshold TH7, the call function of the mobile device is turned off and an overheating prompt is displayed. That is to say, if the battery temperature B_T is greater than or equal to the threshold TH1 and the power amplifier temperature digit value PA_AD is less than or equal to the threshold TH3, it must not exceed 6 hours; the battery temperature B_T is greater than or equal to the threshold TH4 and the power amplifier temperature digit value PA_AD is less than or equal to In case of threshold TH5, it shall not exceed 1 hour; battery temperature B_T is greater than or equal to threshold value TH6 and power amplifier temperature digit When the value PA_AD is less than or equal to the threshold TH7, the call function of the mobile device is immediately turned off. In this way, the embodiment of the invention can meet the requirements of low temperature burns. In the process 20, steps 112, 124, 132 will return to step 100 and determine in step 104 whether the mobile device is charging.

Wherein, the threshold TH1 is 43 ° C (surface temperature is about 43 ° C): the threshold TH2 is 64 (the temperature near the power amplifier module is about 50 ° C); the threshold TH3 is 55 (the temperature near the power amplifier module is about 55 ° C); The threshold TH4 is 45 ° C (surface temperature is about 45 ° C); the threshold TH5 is 47 (the temperature near the power amplifier module is about 60 ° C); the threshold TH6 is 47 (surface temperature is about 48 ° C); the threshold TH7 is 42 ( The temperature near the power amplifier module is about 65 ° C). According to the above embodiment and the value of the threshold value, the schedule table (1) and the table (2) can be summarized. Table (1) is for the mobile device to operate in a non-charged state; Table (2) is for the mobile device to operate in a charged state.

It should be noted that the main purpose of this case is to prevent low-temperature burns, which are used to prevent burns caused by the skin on the surface of the mobile phone. Therefore, it is possible to eliminate the surface overheating caused by the user playing mobile games or watching videos, because playing mobile games or watching The video does not cling to the surface of the phone so it won't burn the skin of the face. Similarly, the possibility of a video phone burning the skin is not considered. In the embodiment of the present invention, a low-temperature burn caused by a large difference in signal power during a general charging call or a call is considered, so when the final threshold is reached, the shutdown is not selected, but the call function is turned off to avoid a bad user experience. .

On the other hand, the threshold value TH1, the threshold value TH2, the threshold value TH3, the threshold value TH4, the threshold value TH5, the threshold value TH6, and the threshold value TH7 can be obtained by the flow 20 of one embodiment of the present invention, as shown in FIG. Show. The process 20 is used to determine the value of the plurality of threshold values in the process 10, which includes the following steps.

Step 200: Establish a test environment.

Step 202: Adjust the power current to a standard value and a selected frequency band when the RF power is 15 dbm and 24 dbm, wherein the mobile device has a maximum power current when the mobile device operates in the frequency band.

Step 204: When the mobile device performs a call and charging in the frequency band (three channels of high, medium, and low), detecting that the mobile device has a hot spot of a highest surface temperature.

Step 206: When one surface temperature of the mobile device reaches 43 ° C, 45 ° C, and 48 ° C, respectively, a plurality of temperature values of a thermistor R1 and a plurality of temperature digital values of a thermistor R2 are obtained.

Step 208: When the RF power is 15 dbm and 24 dbm, the comparison is performed on multiple machines. The plurality of temperature values of the obtained thermistor R1 and the plurality of temperature digital values of the thermistor R2.

Step 210: Differentiate the plurality of temperature values of the thermistor R1 and the plurality of temperature digit values of the thermistor R2 when the mobile device is charged and not charged.

Step 212: Select a radio frequency power of 24 dBm from the temperature values of the plurality of thermistors R1 and a plurality of temperature digital values of the thermistor R2, a battery temperature B_T that is not charged during the mobile device call, and a threshold value of the power amplifier temperature digital value. (Example: TH1, TH3, TH4, TH5, TH6, TH7).

Step 214: From the temperature values of the plurality of thermistors R1 and the plurality of temperature digital values of the thermistor R2, select a threshold value of the radio frequency power of 24 dBm, the battery temperature B_T of the mobile device during charging, and the temperature value of the power amplifier. (Example: TH1, TH2).

Step 216: Is the highest surface temperature consistent with a specification when the RF power is 15 dBm and 24 dBm? If yes, go to step 220; if no, go to step 212.

Step 218: Is the highest surface temperature consistent with a specification when the RF power is 15 dBm and 24 dBm? If yes, go to step 220; if no, go to step 214.

Step 220: Confirm the threshold of the battery temperature B_T and the power amplifier temperature digital value at 43 ° C, 45 ° C, and 48 ° C, and apply the threshold of the battery temperature B_T and the power amplifier temperature digital value to the process 10.

According to the process 20, the frequency band having the maximum power current is selected. The frequency band has a high channel, a medium channel, and a low channel. Since the different mobile devices may have different locations due to component deployment, the location of the hot spots is different. Therefore, the mobile device has a first hot spot having a first highest surface temperature, a second hot spot having a second highest surface temperature, and a third highest point in the high, medium, and low channels, respectively. One of the surface temperatures is the third hot spot. In an embodiment of the invention, the Band 1 band and channel 10562 have a maximum power current. Through a software, a plurality of temperature values of the thermistor R1 and a plurality of temperature digital values of the thermistor R2 are obtained when the surface temperature of the mobile device reaches 43 ° C, 45 ° C, and 48 ° C, respectively. The thermistor R1 is an internal resistance of the battery of the mobile device, and the thermistor R2 is a power amplifier coupled to the mobile device. One of the modules' resistance. Then, when the mobile device is charged and not charged, the plurality of temperature values of the thermistor R1 and the plurality of temperature digital values of the thermistor R2, and the temperature values of the plurality of thermistors R1 and the thermistor Among the plurality of temperature digital values of R2, the threshold of the battery temperature B_T and the power amplifier temperature digital value is selected. The threshold values TH1, TH4, and TH6 in the process 10 are temperature values of the plurality of thermistors R1 when the mobile device is not charged, the RF power is 24 dBm, and the third threshold values TH3, TH5, and TH7 are in the action. The device does not charge, and the RF power is 24dbm, and the temperature of the thermistor R2 is plural. If the threshold of the battery temperature B_T and the power amplifier temperature digital value meets the RF power of 15dbm and 24dbm, the threshold of the battery temperature B_T and the power amplifier temperature digital value is applied to the process 10. If the threshold of the battery temperature B_T and the power amplifier temperature digital value does not meet the RF power of 15dbm and 24dbm, then the threshold of the battery temperature B_T and the power amplifier temperature digital value is re-adjusted.

Please refer to Figures 3-6, and Figures 3-6 are actual test results of an embodiment of the present invention. In the third figure, the test environment: ambient temperature 25 ° C, RF power 15 dbm, continuous talk when charging the phone, maximum surface temperature 41 ° C, limited charging current I is 200 mA, power amplifier temperature digital value PA_AD is 55, battery temperature B_T is 43 ° C, in line with low temperature burn requirements. In the fourth figure, the test environment: the ambient temperature is 35 ° C, the RF power is 15 dBm, the phone is continuously talking during charging, and the maximum surface temperature is 43 ° C. The external temperature has little effect. In Figure 5, the test environment: ambient temperature 25 ° C, RF power is 15dbm, mobile phone long-term conversation, the highest surface temperature is less than 43 °C. When the mobile phone is normally charged, the temperature rises, so the charging current I is limited to 200 mA. Since the charging current I is limited, the temperature drop returns to normal charging, causing the temperature to rise, again limiting the charging current I. Finally, the heat balance is reached. In Figure 6, the test environment: RF power is 24dbm, battery temperature B_T exceeds 45 °C within one hour, the phone has been hung up, in line with low temperature burn requirements. In other embodiments of the present invention, when the battery temperature B_T is detected more than 45 ° C multiple times, the mobile phone is turned off to protect the battery.

Please refer to FIG. 7. FIG. 7 is a schematic diagram of a surface temperature control system 70 according to an embodiment of the present invention. Surface temperature control system 70 is used in a mobile device to control the mobile device Surface temperature. The surface temperature control system 70 includes a battery 700 in which a thermistor R1 is embedded, a power amplifier module 720 in which a thermistor R2 is embedded, a power management chip 740, and a processor 760. The thermistor R2 is used to detect the ambient temperature of the power amplifier module 720. The power management chip 740 is used to detect the temperature of the thermistor R1 and the temperature digital value of R2. The processor 760 is coupled to the power management chip 740 for performing the above process 10 and the process 20 for surface temperature control and threshold selection. On the other hand, the temperature in the vicinity of the power amplifier module 720 can be converted into an 8-bit digit value, which ranges from 0 to 255, through an analog-to-digital converter inside the processor 760 (not shown in FIG. 7). The smaller the temperature, the higher the temperature. In the embodiment of the present invention, when the battery 700 detects that the battery temperature is 45 ° C during charging, the battery 700 automatically turns off charging to protect the battery.

For detailed operation manners of the surface temperature control system 70, reference may be made to the above-mentioned processes 10 and 20, and details are not described herein again.

In summary, the embodiments of the present invention provide a method for controlling a surface temperature of a mobile phone. When the battery temperature is greater than or equal to 43 ° C and the power amplifier temperature digital value is less than or equal to 55, it shall not exceed 6 hours; if the battery temperature is greater than or equal to 45 ° C and the power amplifier temperature digital value is less than or equal to 47, it shall not exceed 1 hour; When the temperature is greater than or equal to 47 ° C and the power amplifier temperature digital value is less than or equal to 42, the call is immediately turned off and there is an overheating prompt. In this way, the embodiments of the present invention can meet the requirements for low temperature burns of mobile phones.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

10‧‧‧ Process

Steps of 100, 102, 104, 106, 108, 110‧‧

112, 114, 116, 118, 120, 122‧‧‧ steps

124, 126, 128, 130, 132, 134‧ ‧ steps

Claims (42)

A method for controlling surface temperature in a mobile device, comprising: periodically reporting a power amplifier temperature digital value and a battery temperature; wherein the battery temperature is greater than or equal to a first threshold value and the power amplifier temperature digital value is less than or equal to When a second threshold is depreciated and the mobile device is charging, limiting a charging current; when the battery temperature is greater than or equal to the first threshold and the power amplifier temperature digital value is less than or equal to a third threshold, determining a first Whether the timer exists; when the first timer already exists, determining whether the first timer expires; when the first timer has not expired, determining whether the battery temperature is greater than or equal to a fourth threshold And the power amplifier temperature digit value is less than or equal to a fifth threshold value; when the battery temperature is greater than or equal to the fourth threshold value and the power amplifier temperature digit value is less than or equal to the fifth threshold value, determining whether a second timer exists When the second timer already exists, determining whether the second timer expires; if the second timer has not yet When the period is full, determining whether the battery temperature is greater than or equal to the sixth threshold value and the power amplifier temperature digit value is less than or equal to a seventh threshold value; and the battery temperature is greater than or equal to the sixth threshold value and the power amplifier temperature digit value When the value is less than or equal to the seventh threshold, the call function of the mobile device is turned off and an overheating prompt is displayed. The method of claim 1, further comprising: determining whether the mobile device is charging when the battery temperature is less than the first threshold or the power amplifier temperature digital value is greater than the second threshold; and While the device is charging, continue charging and determine whether the battery temperature is greater than or equal to the first threshold and the power amplifier temperature digital value is less than or equal to the third threshold. The method of claim 2, further comprising determining, when the mobile device is not charging, determining whether the battery temperature is greater than or equal to the first threshold and the power amplifier temperature digit value is less than or equal to the The third threshold. The method of claim 1, further comprising clearing the first timer when the battery temperature is less than the first threshold or the power amplifier temperature digit is greater than the third threshold. The method of claim 1, further comprising: setting the first timer when the first timer does not exist. The method of claim 1, further comprising, when the first timer expires, turning off the call function of the mobile device and displaying an overheating prompt. The method of claim 1, further comprising clearing the second timer when the battery temperature is less than the fourth threshold or the power amplifier temperature digit value is greater than the fifth threshold. The method of claim 1, further comprising the second timer not being present, setting the second timer. The method of claim 1, further comprising, when the second timer expires, turning off the call function of the mobile device and displaying an overheating prompt. The method of claim 1, further comprising: clearing the first timer and the second timer when the battery temperature is greater than or equal to the sixth threshold and the power amplifier temperature digit value is less than or equal to the seventh threshold . The method of claim 1, further comprising reporting the power amplifier temperature and the battery temperature every minute when the battery temperature is less than the sixth threshold or the power amplifier temperature digital value is greater than the seventh threshold. A method for determining a threshold of a battery temperature and a power amplifier temperature digital value in a mobile device, comprising: selecting a frequency band, wherein the mobile device has a maximum power current when the mobile device operates in the frequency band When the mobile device is in the frequency band for talking and charging, detecting that the mobile device has a hot spot having a highest surface temperature; and the surface temperature of one of the mobile devices reaches a first temperature and a second temperature respectively And a third At a temperature, obtaining a plurality of temperature values of the first thermistor and a plurality of temperature digit values of a second thermistor; when the RF power is a first value and a second value, comparing the plurality of a temperature value of the thermistor and the plurality of temperature digital values of the second thermistor; distinguishing the temperature values of the plurality of first thermistors and the second thermistor when the mobile device is charged and not charged The plurality of temperature digital values; and a threshold of the battery temperature and the power amplifier temperature digital value from the temperature values of the plurality of first thermistors and the plurality of temperature digital values of the second thermistor value. The method of claim 12, wherein the frequency band comprises a high channel, a medium channel, and a low channel. The method of claim 13, wherein detecting the hot spot having the highest surface temperature on the mobile device comprises: detecting that the mobile device has a first highest surface when operating in the high channel a first hot spot of temperature; detecting that the mobile device has a second hot spot on the mobile device when operating in the medium channel; and detecting that the mobile device is operating in the low channel The mobile device has a third hot spot on the third highest surface temperature. The method of claim 12, wherein the first value is 15 dbm and the second value is 24 dbm. The method of claim 12, wherein the threshold of the battery temperature and the power amplifier temperature value is not charged by the mobile device, and the temperature of the plurality of first thermistors when the RF power is the second value And a plurality of temperature digital values of the second thermistor. The method of claim 16, further comprising testing whether the highest surface temperature conforms to a specification standard when the RF power is the first value and the second value. The method of claim 18, further comprising the fact that the maximum surface temperature does not conform to the specification standard, Adjust the battery temperature and the threshold value of the power amplifier temperature digital value. The method of claim 12, wherein the battery temperature and the power amplifier temperature value are the temperature values of the plurality of first thermistors when the mobile device is charged, the RF power is the second value The plurality of temperature digital values of the second thermistor. The method of claim 19, further comprising testing whether the highest surface temperature conforms to a specification standard when the RF power is the first value and the second value. The method of claim 20, further comprising adjusting the battery temperature and a threshold value of the power amplifier temperature digital value if the maximum surface temperature does not conform to the specification. A surface temperature control system for a mobile device, comprising: a battery comprising a first thermistor; a power amplifier module comprising a second thermistor coupled to the power amplifier module; a power management chip for detecting a temperature of the first thermistor and a temperature of the second thermistor; and a processor for performing a surface temperature control method; wherein the surface temperature control method comprises: Periodically reporting the temperature digital value of the power amplifier module and the temperature of the battery; when the temperature of the battery is greater than or equal to a first threshold and the temperature digital value of the power amplifier module is less than or equal to a second threshold When the mobile device is charging, limiting a charging current; determining whether a first timer exists if the temperature of the battery is greater than or equal to the first threshold and the temperature digital value of the power amplifier module is less than or equal to a third threshold When the first timer already exists, determining whether the first timer expires; when the first timer has not expired, determining No temperature of the battery is larger than a fourth threshold value is equal to the temperature of the power amplifier module and the digital value is greater than equal to a fifth threshold; Determining whether a second timer exists when the temperature of the battery is greater than or equal to the fourth threshold and the temperature digit value of the power amplifier module is less than or equal to the fifth threshold; when the second timer already exists, Determining whether the second timer expires; when the second timer has not expired, determining whether the temperature of the battery is greater than or equal to the sixth threshold and the temperature digit value of the power amplifier module is less than or equal to one The threshold value is seven; and when the temperature of the battery is greater than or equal to the sixth threshold and the temperature digit value of the power amplifier module is less than or equal to the seventh threshold, the call function of the mobile device is turned off and an overheating prompt is displayed. The surface temperature control system of claim 22, wherein the surface temperature control method further comprises: when the temperature of the battery is less than the first threshold or the temperature digital value of the power amplifier module is greater than the second threshold; Determining whether the mobile device is charging; and when the mobile device is charging, continuing to charge and determining whether the temperature of the battery is greater than or equal to the first threshold and the temperature digital value of the power amplifier module is less than or equal to the third threshold . The surface temperature control system of claim 22, wherein the surface temperature control method is further included when the mobile device is not charging, determining whether the temperature of the battery is greater than or equal to the first threshold and the temperature of the power amplifier module The value is less than or equal to the third threshold. The surface temperature control system of claim 22, wherein the surface temperature control method is further included when the temperature of the battery is less than the first threshold or the temperature digital value of the power amplifier module is greater than the third threshold The first timer. The surface temperature control system of claim 22, wherein the surface temperature control method is further included in the first timer not being set, the first timer being set. The surface temperature control system of claim 22, wherein the surface temperature control method further comprises When the first timer expires, the call function of the mobile device is turned off and an overheating prompt is displayed. The surface temperature control system of claim 22, wherein the surface temperature control method is further included when the temperature of the battery is less than the fourth threshold or the temperature digital value of the power amplifier module is greater than the fifth threshold The second timer. The surface temperature control system of claim 22, wherein the surface temperature control method is further included in the second timer not being present, the second timer being set. The surface temperature control system of claim 22, wherein the surface temperature control method is further included when the second timer expires, the call function of the mobile device is turned off and an overheating prompt is displayed. The surface temperature control system of claim 22, wherein the surface temperature control method is further included when the temperature of the battery is greater than or equal to the sixth threshold and the temperature digital value of the power amplifier module is less than or equal to the seventh threshold The first timer and the second timer are cleared. The surface temperature control system of claim 22, wherein the surface temperature control method is further included when the temperature of the battery is less than the sixth threshold or the temperature digital value of the power amplifier module is greater than the seventh threshold The power amplifier temperature and the battery temperature are reported. The surface temperature control system of claim 22, wherein the processor is further configured to perform a threshold determination method; wherein the threshold determination method comprises: selecting a frequency band, wherein the mobile device operates in the frequency band The mobile device has a maximum power current; when the mobile device performs a call and charging in the frequency band, detecting that the mobile device has a hot spot having a highest surface temperature; and the surface temperature of one of the mobile devices reaches a first temperature, a second temperature, and a third temperature, obtaining a temperature value of the first thermistor and a plurality of temperature digital values of the second thermistor; When the RF power is a first value and a second value, comparing the temperature value of the first thermistor with the plurality of temperature digit values of the second thermistor; distinguishing the mobile device from charging and not charging a temperature value of the first thermistor and the plurality of temperature digit values of the second thermistor; and a temperature value from the first thermistor and the plurality of temperature digits of the second thermistor For the value, the first threshold value, the second threshold value, the third threshold value, the fourth threshold value, the fifth threshold value, the sixth threshold value, and the seventh threshold value are selected. The surface temperature control system of claim 33, wherein the frequency band comprises a high channel, a medium channel, and a low channel. The surface temperature control system of claim 34, wherein detecting the hot spot having the highest surface temperature on the mobile device comprises: detecting that the mobile device has a first a first hot spot of one of the highest surface temperatures; detecting that the mobile device has a second hot spot on the mobile device when operating in the middle channel; and detecting that the mobile device operates at the low The mobile device has a third hot spot on the mobile device that has a third highest surface temperature. The surface temperature control system of claim 33, wherein the first value is 15 dBm and the second value is 24 dBm. The surface temperature control system of claim 33, wherein the first threshold value, the fourth threshold value, and the sixth threshold value are the first time when the mobile device is not charged, and the RF power is the second value. The temperature value of the thermistor, and the third threshold value, the fifth threshold value, and the seventh threshold value are the second thermistor when the mobile device is not charged, and the RF power is the second value A plurality of temperature digital values. The surface temperature control system of claim 37, wherein the threshold value determining method further comprises testing whether the highest surface temperature is when the RF power is the first value and the second value One standard. The surface temperature control system of claim 38, wherein the threshold value determining method is further included in the maximum surface temperature not meeting the specification standard, adjusting the first threshold value, the third threshold value, the fourth threshold value, The fifth threshold value, the sixth threshold value, and the seventh threshold value. The surface temperature control system of claim 33, wherein the first threshold is a temperature value of the first thermistor when the mobile device is charged, and the second threshold is when the RF power is the second value. And a temperature digital value of the second thermistor when the RF power is the second value during charging of the mobile device. The surface temperature control system of claim 40, wherein the threshold value determining method further comprises testing whether the highest surface temperature conforms to a specification standard when the RF power is the first value and the second value. The surface temperature control system of claim 41, wherein the threshold value determining method is further included in the maximum surface temperature not meeting the specification standard, adjusting the first threshold value and the second threshold value.