"87W, isn't this a laptop charger? Isn't that big power going to burn the phone?"
Why? It’s all in 9102. Is there any worry that the charger will fill the phone? Xiaobian turned over the comment area and found that there are still many people who are concerned about this issue.
So, will the high-power charger burn the phone?
Before answering this question, we must first understand the output interface type of the charger and its working mode.
First, the charger output interface and working mode
At present, the output interface of the charger on the market can be roughly divided into two types, one is USB-A, and the other is USB-C.
Currently, the most common is the USB-A interface. This interface has been in use for more than 20 years. We can still see it in many electronic digital products. There are also USB-A interface products on the market. With a idiom, "old and strong" is suitable.
The shape of the USB-A interface is rectangular. Most people should touch the back of the computer case for the first time. At least 90 people and people in the previous era are like this. In addition to the shape of the outer body, its most obvious feature is the four metal shrapnel (contact), two of which are responsible for power transmission (positive VCC, ground GND), and the other two shrapnel are responsible for data transmission (data is D+ and The data is negative D-).
In the fast charge charger of USB-A output, the D+ and D- signal lines are responsible for transmitting the voltage signal that changes according to a certain rule, and the mobile phone pairs the “dark number”, the dark number is on, and the charger outputs high voltage or large. Current (When the output exceeds 3A, the mobile phone will also detect the line set of the charging line), otherwise the default D+, D- short circuit, the protocol is DCP, and the output is 5V/1.5A.
The above picture is a small series using the ChargerLAB Power-Z KM001 tester for the host computer to monitor the QC charger.Millet9 The curve of charging, the green curve is the D+ voltage curve of the USB-A port of the charger, and the orange is the D-voltage curve.
Charging for about 4 seconds, when the millet 9 is connected to the charger, the charger changes the voltage value of D+ and D-. Millet 9 detects the voltage value change of D+ and D-. This change is in accordance with the QC fast charging voltage characteristic. After the charger voltage and current start to rise, enter the QC fast charge, just like the secret code of the spy, the "dark number" is right to give you something.
In addition to the use of D +, D - "dark" for protocol judgment, there are some fast charge protocols that use the current pulse signal to match the secret number, such as MediaTek's PE fast charge. Xiaobian uses the ChargerLAB Power-Z KM001 tester to monitor the change curve of the PE charger to the Meizu 16th Plus when it is charged. When charging the Meizu 16th Plus, the current suddenly disappears. This is the current pulse signal sent to the Meizu 16th Plus (the position of the red circle in the picture). The break is a bit like the "Moss password." Meizu 16th Plus receives these pulse signals and the charger on the opposite sign, then the voltage and current begin to rise into the PE fast charge.
About the USB-C interface, its shape is similar to a flat oval shape, smaller than the USB-A, but the internal contacts are up to 24Pin, which is six times that of the ordinary USB-A interface. More contacts mean more powerful functions, and this is true. Whether it is power transmission or data transmission, USB-C is much more powerful than USB-A. At present, more and more devices use USB-C interface. This is the trend of future development.
In the USB-C charger (PD fast charge), the signal is transmitted through the CC line. The charger and the mobile phone will “talk” to each other to exchange information. The charger will first tell the mobile phone with its own power supply information, and the mobile phone will apply. A voltage and current that is acceptable to you. If there is no suitable voltage position, 5V charging or no charging will be selected by default. Just like the following.
PD Charger: I have 5 power supply positions.
Mobile: Received, I want a 5V/3A power supply.
PD Charger: Received, no problem, I will immediately supply you with 5V/3A gear.
PD charger: The power supply position has been adjusted to 5V/3A.
Mobile: Ok, I have already received it. Now I want a 9V/3A power supply.
PD Charger: Received, no problem, I will immediately supply you with 9V/3A gear.
PD charger: The power supply has been adjusted to 9V/3A.
Mobile: Ok, I have already received it, please keep it.
The following is a small series of two common high-power charger Huawei 40W, Apple 87W as an example, for everyone to actually test it, to see if it is as Xiaobian said, "high-power charger will not burn the phone."
Second, the actual test
Huawei 40W charger is a USB-A interface charger, which supports 40W SCP fast charge, QC fast charge, FCP fast charge.
First we use it to fill it upiPhoneXS. iPhone XS mobile phone supports PD fast charging, Apple 2.4A protocol, when it is powered on with the charger, it will first ask the charger whether there is Apple2.4 charging protocol through D+, D- voltage change, if there is no Apple2.4A agreement Will look at the support does not support the DCP1.5A mode (D + D - direct connectivity), if you do not have any recognition, you can only charge with the ancestral Wufu one An 5V / 1A (0.96A). As can be seen from the figure, the power of Huawei 40W charger for iPhone XS is about 5W. It is charging, and the mobile phone is not damaged because the charger is "powerful".
Let's take a look at the more powerful Apple 87W charger for iPhone XS. Apple's 87W charger's charger interface is USB-C. Before we learned that the USB-C port has more contacts than the USB-A, the number of contacts is more intelligent.
Apple 87W charger is a charger that supports USB PD fast charging. When it charges iPhone XS, they will tell each other their own power supply and charging information, just like two people introduce themselves to each other. As you can see, the current iPhone XS power is 18.99W, which belongs to the safe power range of the phone. The iPhone XS is not damaged because the charger is as high as 87W.
Some people may say: You are testing Apple mobile phones as an example. What about Android phones?
Android phone is actually the same, here Xiaobian 8 as an example, Xiaomi 8 supports PD fast charge, QC fast charge. The charger still uses Huawei 40W and Apple 87W. Because PD fast charge is to exchange information through CC core communication, USB-A interface does not have CC core, so it does not have CC communication function. When Xiaomi 8 and charger are powered on, it will skip PD communication and pass D+ directly. D-voltage change to ask if the charger has a QC fast charge protocol. If it is not, then there will be a DCP protocol, and so on.
Huawei's charger supports QC fast charging. In the above picture, you can see that the current charging power of Xiaomi 8 is 12.77W, and the handshake QC is fast charging. It belongs to the safe power range of the mobile phone, and the mobile phone is in normal charging state.
Apple 87W charger filled with Xiaomi 8, the priority handshake handshake PD fast charging protocol, the current power is 15.64W, and there is no case of charging the phone.
Moreover, most mobile phones have a certain high-voltage protection mechanism. When the input voltage, current, and power are too large, they will automatically turn off the power and refuse self-protection. The above picture shows the PD charger charging the Meizu mobile phone with different voltage positions. Pay attention to the marker in the POWER-Z tester display and the charging status in the upper right corner of the phone screen. It can be seen that 5V, 9V, 12V can be charged normally, 15V, 20V mobile phones will detect excessive voltage, refuse to charge and protect the mobile phone from damage. Of course, the self-protection high voltage range of each mobile phone is different. Don't imitate it easily, it may cause damage to the mobile phone.
Third, the charging head network summary
Will a high-power charger burn the phone? The answer is: no. Because the charger is charging the phone, they will perform a series of communication and communication, and can adjust the voltage and current at any time. For the charger that uses the USB-A interface to charge the phone, the two will each report the "connector code". If the match is made, it will be charged. If the phone is not matched, the phone will refuse to be charged; and the USB-C port will be used for charging. When charging, the communication between the mobile phone and the charger will be more frequent and accurate, and communication will continue to ensure the best charging solution.
The power parameter of the charger is one of its performance indicators, indicating how much output power the charger can achieve.
Using an easy-to-understand example, the charger is a car, and the output power of the charger is how fast the car can drive (200 km/h). The phone is like a driver, he controls the accelerator pedal of the car.
How fast the car is driving, everything is to see the driver's needs, you can slowly go to buy food, you can go at a high speed of 120 kilometers per hour. The output power of the charger is also to look at the mobile phone, how much power the mobile phone needs, and how much the charger outputs to the mobile phone.
So, don't worry that a powerful charger will burn your phone.
However, don't use some exotic chargers, or 48V, 72V, which is not a power adapter for charging mobile phones, or even use a 220V mobile phone directly. This is definitely bad. You must pay more attention.