Today's hardware of the electronic products, including mobile phones, are rapidly updating and iterating, and only the battery has always been the shortest board of the barrel. Because the energy density of the battery has been difficult to achieve breakthrough, at present, only by improving the battery capacity and charging efficiency can the battery be supplemented, and the improvement of the battery capacity often needs to sacrifice the volume, so the fast charging technology becomes the breakthrough most easy to achieve. At present, wireless fast charging has been officially commercial, which can increase the wireless charge power of mobile phones to 20W. Our huawei wireless fast charger is one of the example. The actual effect is basically the same as the previous generation flagship's wired charging!
It can realize 20W wireless fast charging. The key is to use charge pump in the mobile phone. Compared with other mobile phones, Xiaomi 9 has greatly developed the use scenario of charge pump. In the wireless charging, it uses precise voltage reduction to supply twice the battery voltage for the mobile phone. After the mobile phone receives it, it uses high-efficiency charge pump to reduce the voltage to charge the battery. Compared with the traditional scheme, the current at the receiving end is constant and the power at the receiving end is increasing.
At present, there are two common schemes of fast charging: high voltage and low current, low voltage and high current. Charge pump technology can achieve both high voltage and high current. The principle is to use capacitor as energy storage element for voltage transformation, which is simply to charge the capacitor in the input circuit, and then discharge the capacitor in the output circuit, so as to achieve the rise and fall of voltage, and the conversion rate is very high! We've already have the 15w huawei wireless quick charge, which shows great effiency.
The wireless charging power of the mobile phone is 20W, and the receiving power of the mobile phone is 15V1.34A. Because the charge pump can't bear too much voltage change, use buck to reduce the voltage before, and it can realize 20mV fine voltage regulation, but its greater role is to stabilize the voltage, and then use the charge pump to carry out half voltage conversion to reach the battery voltage, which better solves the short board of the charge pump! As for wireless charging, electromagnetic coils are used for transmission, and charge pump technology is used for power improvement. In addition, the terminal coil of the mobile phone has also been adjusted. The new multi strand coil adding 5-layer nanocrystalline material is used to reduce the consumption, interference and temperature.