Created
May 26, 2019 21:13
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Xiaomi Redmi Note 4X (Snapdragon - Mido) charging current limitation
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TL;DR: no, it won't be beneficial to use a charger with QC3.0, | |
it won't charge better/quicker your Xiaomi Redmi Note 4X (Snapdragon - Mido) | |
Disassembly guide for pics: | |
http://en.miui.com/thread-554086-1-1.html | |
PMM8952 Power Management Module | |
https://developer.qualcomm.com/download/sd600/pmm8920-power-management-module-device-specification.pdf | |
Chip is limited to 5V and 2A max if everything is ideal | |
but in real life.. it is never ideal | |
below 20% and above around 70..75 it is limited. | |
Around between 30..70% the max (ideally) around 1.6A. | |
Max. was 1.9A if I recall correctly | |
(depends on the kernel and environmental conditions). | |
The chip cannot do more than QC2.0+ in this phone. | |
That is more than QC2.0 but way less than QC3.0, | |
it's fancy marketing BS was "USB Fast Charge" | |
when Mido has been introduced. | |
This (I mean fast and quick charge functionality) | |
was a distinguisher function / feature between | |
budget and mid-range phones of Xiaomi back in 2017. | |
The chip itself would be able to work at 5V*3A or 9V*2A | |
but the actual power management chip in the phone | |
is not able to use 9V, only 5V | |
(forcefully regulated by the manufacturer, | |
probably because of heat dissipation, marketing and | |
licensing to Qualcomm (Xiaomi did not pay for it..)) | |
and not able to go above 2A | |
and you should consider the thermal dissipation as well, | |
that's why the chip is going way below 2A, it's heating up.. | |
and thus the PM chip is regulating the current | |
(max. 1.9A as far as I remember my actual measurement values | |
and around 1.3A when it's already on charger for about 10..20 mins | |
(heating up a bit and the battery is between 30..70%)). | |
Hope this helps - but probably not. | |
PS: facts are facts, you cannot bend physics nor engineering with software mods. |
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