At present, the battery capacity of mobile phones is generally more than two or three thousand MAH. Using the traditional 5V / 1A charger, it takes at least three hours to fully charge a battery, which is much longer than that of Nokia mobile phones in more than one hour. With the improvement of battery capacity, the original charger power can not meet the needs of charging, so QC fast charging protocol chip fast charging technology appears.
Principle of QC fast charging protocol chip
Major mobile phone manufacturers have launched their own fast charging technology. Its principle is to improve the charging current and voltage to realize high-power charging. Simply put, the input power of the charging port = input voltage x input current. Generally, the mobile phone charger will have a charging curve to achieve the highest charging efficiency by controlling different voltages and currents.
Generally speaking, the most efficient way is to start with constant current charging (faster charging speed), then constant voltage charging (the charging speed is down because the voltage of the battery itself is up), and finally trickle charging (after being fully charged, compensate for the capacity loss caused by self discharge).
Technical classification of QC fast charging protocol chip
At present, the fast charging technology used in mobile phones is mainly divided into two categories: "high voltage low current" and "low voltage high current".
Fast charging representatives of "high voltage and low current": Qualcomm's quickcharge and MediaTek's pumpexpress
Fast charging representatives of "low voltage and high current": oppo vooc, one plus dash and Huawei supercharge
Apple does not have its own fast charging technology, and the relatively general USB PD 3.0 standard is used to realize real fast charging for models above iPhone 8.
01 Qualcomm QC
Qualcomm's quick charge x.0 QC fast charge protocol chip is a comprehensive set of battery management technology, which improves the charging speed by increasing current and voltage. So far, Qualcomm has launched five versions of QC standards.
Qc1.0: voltage and current rise to 5V@2A , the charging time is reduced by 40%.
Qc2.0: compared with the old standard, QC fast charging protocol chip 2.0 has changed the charging voltage epoch-making, from the conventional 5V maintained for many years to 9V / 12V / 20V. Under the same 2A current as qc1.0, 18W high-power power power transmission is realized, and the wire rod does not need special treatment, and the old wire materials can be universal. Qc2.0 is divided into class A and class B industry standards. Standard a: 5V, 9V and 12V output voltage, and standard B: 5V, 9V, 12V and 20V output voltage. When the voltage is increased, the power increases, but the efficiency decreases. When the voltage increases by one gear, the efficiency decreases by about 10%, and most of these energy is converted into heat. Therefore, almost no one uses the 20V voltage gear, and only three gears of 5V, 9V and 12V are reserved.
Qc3.0: on the basis of qc2.0 9V / 12V voltage, further subdivide the voltage range, adopt the unique intelligent negotiation for optimum voltage (inov) algorithm, set the voltage at 200mV as the first level, the lowest voltage can be down to 3.6V, the highest voltage is 20V, and is downward compatible with qc2.0. Because the type C interface is fully used to replace the original micro USB interface, the maximum current is also increased to 3a. Because the voltage is lower, the efficiency is increased by up to 38%, the charging speed is increased by 27%, and the heating is reduced by 45%. Qc3.0 is good, but Google doesn't agree. How can you make a separate set for Qualcomm? If you use my system, you must use USB PD protocol for me. My arm can't twist my thigh. Qualcomm is soft and launches qc4.0.
Qc4.0: increase the power to 28w again and add support for USB PD. The 12V voltage level is cancelled, the maximum output of 5V is 5.6A, and the maximum output of 9V is 3a, and the voltage level continues to be subdivided to 20mV.
However, just six months after the release of qc4.0 standard, Qualcomm launched an upgraded version of qc4 + standard. Qc4 + does not need to be used with a new chip, including all the advantages of qc4 and three enhancements.
02 MediaTek pump Express Technology
MediaTek's new fast charging technology pump express is built into the power management IC of PMIC. It allows the charger to determine the initial voltage required for charging according to the current. The PMIC sends a pulse current command and transmits it to the charger through USB VBUS. The charger adjusts the output voltage according to this command, and the voltage gradually increases to up to 5V to reach the maximum charging current. At present, pump Express has two technical specifications, one is pump express with an output power of less than 10W, and the other is pump express plus with an output power of more than 15W.
At present, with the fast charging mode of MediaTek, power chip factories such as dialog, on bridge and Tongjia have developed exclusive power management IC for MediaTek. It does not need to use USB data communication port, and the line is simple. In terms of architecture, it is almost the same as the current traditional USB charger, and the cost improvement is also low, which is very suitable for promotion in medium and low-end mobile phones.
03 vooc flash charging technology
Vooc flash charging technology is a typical representative of "low voltage and high current" fast charging scheme. As we all know, high current will also lead to hot mobile phones, resulting in potential safety hazards. Vooc flash charging technology innovatively transplants the charging control circuit to the adapter, that is, transplants the largest heating source to the adapter. In this way, the control circuit is in the adapter, and the charged battery is in the mobile phone end. The heating of the mobile phone during charging can be well solved. The first generation vooc charger has a huge volume, and there is a risk of disconnection at the charging line interface. Fortunately, with the progress of technology, the second generation vooc Mini charger has come out. Its volume is equivalent to the standard USB charger, with high portability and perfect security. The biggest disadvantage of vooc technology is that it is only applicable to oppo products and has poor compatibility.
There are two different hardware designs in vooc flash charging system - 7-pin micro USB interface, 8-metal contact battery and corresponding internal MCU circuit. The battery part can be understood as a series connection formed by two ordinary batteries. According to the output of 5A, vooc flash charging is equivalent to charging the two batteries with a current of 2.5A respectively. In order to better control the charging process (for example, the control circuit needs to monitor the battery voltage and temperature in real time), oppo specially adds an intelligent control chip MCU at the adapter end, which realizes the charging control circuit and intelligently controls the whole charging process.
04 Fast Charger Protocol & SuperCharge
Huawei's initial fast charging uses technologies similar to Qualcomm's QC 2.0 and MediaTek's PE fast charging. The output specification is 9V 2a, which belongs to "high voltage low current" fast charging. After 2016, the "low voltage and high current" fast charging technology equivalent to vooc and dash is adopted, and the charging output voltage supports dynamic adjustment from 3.5V to 5V.
Back to fast charging, it has developed for so many years. In just seven years, the charging power of smart phones has increased from 5W to 65W, 13 times, and the charging speed has also developed from "charging for 5 minutes and talking for 2 hours" to "charging for 5 minutes and turning black for 2 hours".
As for whether the fast charging technology is good or bad, Wen Shan said that the momentum is still very good. Once we had to plug in a charger to have a safe sleep, but now, we only need to brush our teeth and wash our face for more than ten minutes, and the power of the mobile phone can be "resurrected with blood". Electricity anxiety has become a "pseudo proposition".