Xiaomi launched its 2019 Xiaolong 855 flagship mobile phone Xiaomi 9 on February 20. One of the biggest highlights of this mobile phone is that it supports 20W Wireless Flash charging, which is also the world's first flagship mobile phone supporting 20W Wireless Flash charging, so it has attracted the attention of many consumers. How about the 20W Wireless Flash charging of Xiaomi 9 compared with the wired fast charging of Xiaomi 8? This article brings you the performance introduction of Xiaomi 9 20W Wireless Flash charging and the comparison between Xiaomi 9 20W Wireless Flash charging and Xiaomi 8 wired fast charging. Let's have a look.
On March 1, according to the official wechat of Xiaomi mobile phone, the key for Xiaomi 9 to realize the world's first 20W wireless charging is to adopt the same half pressure direct charging scheme as wired fast charging, that is, the charge pump technology we often call.
Charge pump technology is a scheme that can charge at high voltage and use high current. As a DC-DC (DC-DC) converter, it uses capacitance as energy storage element for voltage conversion. Its conversion efficiency is very high, almost 100%.
The maximum output power of Xiaomi 9 20W wireless charging base is about 20W, allowing the mobile phone terminal to input with a receiving power of 15V / 1.34a.
The intermediate stage uses 95% high efficiency DC-DC (DC-DC) (Buck) to reduce the voltage to twice the battery voltage. It can also realize 20mV fine voltage regulation to ensure the charging stability of the next stage charge pump. The latter stage uses charge pump technology for 2:1 voltage transformation operation to charge the power into the lithium battery, and the conversion efficiency of this intermediate stage is as high as 97% - 98%.
Xiaomi 9 wireless fast charging PK Xiaomi 8 wired fast charging
The measured results of the two mobile phones with similar battery capacity show that it takes Xiaomi 9 4 minutes faster than Xiaomi 8 to charge to 100%. The 20W wireless fast charging of Xiaomi 9 is faster than the 18W wired charging of Xiaomi 8.
Three flagship wireless charging speed competition: Xiaomi 9 win
The measured charging results of the three mainstream flagship models are shown in the figure. Xiaomi 9 was charged in 1 hour and 30 minutes, mate 20 Pro took 2 hours and 4 minutes, and iPhone XS Max took 4 hours and 17 minutes to be fully charged.