The Xiaomi Mi 10 Ultra is the first phone with Qualcomm’s 100W+ Quick Charge 5 technology
The new Xiaomi Mi 10 Ultra is an exciting smartphone as it’s the pinnacle of 10 years of Xiaomi’s growth in the smartphone business. Featuring a 120Hz refresh rate OLED display made by TCL’s CSOT, a 48MP Quad Bayer sensor with a 120mm-equivalent, 5x optical lens for up to 120X zoom, and 120W fast wired charging, the Mi 10 Ultra is yet more proof that Xiaomi can produce innovative smartphone hardware. That last figure is one of the more exciting features of the Mi 10 Ultra as it’s actually made possible from a collaboration between Xiaomi and Qualcomm. In fact, the Mi 10 Ultra is the first smartphone to launch with Qualcomm’s new Quick Charge 5 technology.
— Qualcomm (@Qualcomm) August 12, 2020
Announced late last month, Quick Charge 5 is the latest version of Qualcomm’s fast charging technology for mobile devices. Qualcomm boasts that it is the first commercially viable fast charging platform for smartphones that supports over 100W charging power. Quick Charge 5’s charge negotiation protocol is based on the existing USB Power Delivery Programmable Power Supply (USB PD-PPS) standard, and Qualcomm’s new SMB1396 and SMB1398 PMICs support 2S battery systems (dual cell batteries connected in series.) This allows for doubling the voltage for the same current, thereby doubling the charging speed. A device with 4,500mAh in total battery capacity, for example, can charge from 0 to 50% in just five minutes (a 1.5 C-rate). If you’re wondering how Quick Charge 5 affects the longevity of a battery, Qualcomm says that the new technology uses Qualcomm’s Battery Saver algorithm and the new Qualcomm Smart Identification of Adapter Capabilities technology to support “unparalleled efficiency.”
In a blog post published on Weibo, Xiaomi further details the 120W fast charging technology in the Mi 10 Ultra. Xiaomi says the Mi 10 Ultra can be charged to 100% in just 23 minutes. They achieved this by converting two high-voltage currents of 20V/3A into two low-voltage currents of 10V/6A and then converting that to 10V/12A which is finally split among both 2,250mAh batteries connected in series. In collaboration with Qualcomm, Xiaomi says they achieved 98.5% conversion efficiency with this charging system.
In the blog post, Xiaomi also describes the changes they made to the battery and internal components to support this fast 120W charging. For example, the phone’s “butterfly double string battery” design is contrasted against traditional side-by-side dual cell battery designs, which Xiaomi says allows for a larger battery capacity without taking up more volume. The battery cells also have a “low internal resistance tab design” to reduce the resistance and temperature by 36% and 4.8°C respectively. The graphene material at the positive electrode is substantially more conductive than traditional carbon materials, the thicker and lower impedance “dual FPC connection” between the battery and motherboard reduces energy loss and heat generation, and the “Battery Sense” voltage monitoring technology accurately detects the true voltage of the battery cell to avoid errors caused by the battery protection circuit. Xiaomi says that the Mi 10 Ultra loses only 10% of its total battery capacity over 800 full charge-discharge cycles.