Now the popularity of mobile phones in the general public users has been quite high, many people maintain a replacement frequency of about a year, sometimes, the extra charger connector has become a more troublesome thing, is thrown, or continue use? If you continue to use it, many people will be scared. The brand is different. Will there be any problems with the old charger?

Well, before that, let's solve one problem first: How does fast charging work?

 

First of all, the definition of USB connector is basically determined, micro USB has a total of 5 lines;

The current five lines under the current definition can provide the highest charging indicator of 5V 2A . So how is the definition of fast charge?

 

Previously we had discussed the formula for electric power: P=UI . Therefore, if we want to increase the electric power, then only: 1. Raise the voltage; 2. Raise the electric current.

 

One way to increase voltage is Qualcomm's quickcharge and MTK 's PE+ protocol. Qualcomm's QC Fast Charge 2.0 uses 5v , 9v , 12v , and 20v four gears, and 3.0 is seamlessly adjustable at 200mv , while MTK 's PE+ protocol is similar to it. There are also 5v , 7v , 9v , 12v fourth gear, and the new specification, 500mv a seamless adjustment.

Since the voltage has increased and it has broken through the normal USB interface voltage, then how does the charger ensure normal operation?

 

Of course, we need to make some transactions ~

The content of this "transaction" is: through the mobile phone charger and the power management chip inside the mobile phone, the voltage communication between them is performed. At the very beginning when the charger was plugged in to the phone, VDDC+ and VDDC- were shorted to the data transmission line, and the charging voltage was maintained at the standard 5V normal charge. After that, the mobile phone will talk to the charger about the charging protocol. The mobile phone will send the identification voltage to the charger (setting value is 0.325v ). If the charger supports fast charging, after the voltage is recognized, the data line will be short-circuited. At this time, the system process in the mobile phone will be set according to the highest voltage value set in the system, and the mobile phone will set different voltage feedbacks for the charger on the data transmission line, according to the voltage values ​​of VDDC + and VDDC- , thereby providing quick charging for the mobile phone. The function.

The above is a brief description of Qualcomm's QC fast charging protocol. MTK 's protocol process is similar, but the verification process is somewhat different.

 

Therefore, in fact, prior to the Qualcomm mobile fast charging protocol, the mobile phone first needs to recognize the fast charge protocol. Only through the fast charging protocol, the mobile phone using the Qualcomm chip can increase the voltage of the charging terminal for fast charging.

 

If the mobile phone itself does not support fast charging or the mode does not match, it will not respond to the fast charging verification signal, and will not stay in the standard 5V charging voltage process until the high voltage charging section . Similarly, if you use an older charger, the charger will not react to the signal sent by the phone and will only perform the normal charging process.

 

So the conclusion is here: For Qualcomm's fast charge system, mixing the charger will not cause any problems, but it will become a regular charging parameter.

And oppo flash charge piece is slightly different, we have mentioned before, oppo fast charge mode is the use of high-current, high current transfer wire by increasing the reach microUSB defined in the original, so oppo's scope is much smaller Because of the change in the style and definition of the micro USB interface, oppo is best for special planes.

Speaking of this, everyone can be assured that: support for high-voltage fast charge, use the standard USB definition of the phone, as long as you are not using a cottage charger, qualified charger free replacement charge will not have any security risks, Only the difference between charging faster and slower, nothing more.

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