In order to fulfill the basic functions of our service, the user hereby agrees to allow Xiaomi to collect, process and use personal information which shall include but not be limited to written threads, pictures, comments, replies in the Mi Community, and relevant data types listed in Xiaomi's Private Policy. By selecting "Agree", you agree to Xiaomi's Private Policy and Content Policy .

Redmi 7/7A

[Discussion] [How it Works #12] What is Fast Charging in a Smartphone!

2019-07-02 02:52:51
1869 56

Dear Mi Fans!

This is a new series about all parts your smartphones and how it works on device!
Almost all modern smartphones are equipped - Fast charging. But not all know how it work's! Today you know it and more about this smartphone detail.  We will not talk about how they are produced! And let's talk about the main concepts and technical characteristics. I think many will be interested to find out this information.

What is Fast charging in mobile phone!?

Formally, the name of the function reflects its essence - a smartphone can quickly charge. To be more precise, it can charge faster than smartphones that are not endowed with the function of fast charging. For example, Sasmung Galaxy Note 4 with a battery capacity of just over 3000 mAh can charge as much as 50% in 30 minutes! Agree, the result is impressive. True, full charge lasts much longer, but still the speed of the charge will be high.

While fast charging is supported only by certain processors. One of the leaders in this area is Qualcomm, it manufactures Snapdragon processors, which are used in many smartphones. It works proprietary technology Quick Charge ("Fast Charging") only if you have the appropriate power adapter. If you use a different adapter, you can forget about the technology.

How is the quick charge of the smartphone?
Each device is designed for a specific current and voltage, that is, when charging, the device only passes a certain current. Special adapters that are used in smartphones with support for fast charging, allow the device to take more voltage and amperage. Thanks to this technology, the smartphone charges much faster.

True, there is one very important feature that must be taken into account. The fact is that the accelerated charging of the device is divided into several stages. At the very first stage, the maximum current is applied, so that the charge of the device grows literally before our eyes. However, on reaching 50-70% of the current begins to decline sharply, resulting in the charging speed to the remaining 100% decreases. Why is this done? It's simple - so that the battery does not overheat and does not fail. By the way, this is why in advertisements of fast-charging technology they say something like: “In just 30 minutes you can charge your smartphone up to 50%!”, Because before the remaining 100% the device can charge for another hour, or even longer.

What is the need for fast charging technology?
It is clear that this allows you to reduce the charging time of the device, which, of course, is a big plus. In fact, the main focus is on charging for the first 10-20 minutes. Example: your smartphone is discharging, literally 5% is left. You run into a cafe, order coffee and charge the device, since the power adapter is with you. For those 10-15 minutes that you drink coffee, the device will have time to charge up to 35-50%, which is enough for the rest of the day. And, in our opinion, this is a huge advantage of this technology.

By the way, a similar technology is used on many electric vehicles: in the first couple of hours, batteries can charge up to 50-80%, and the remaining charge can take another 5-6 hours, if not more. Everything you need to know about this technology and its types. With an increase in diagonal and screen resolution, as well as processor power, the load on the battery also increased. We no longer have the usual charge of 5 volts and 2 amps. With such a normal charge, the battery charges for at least two hours. Therefore, manufacturers have adopted the technology of fast charging (fast charge). But there were questions. How harmful is fast charging for batteries? Is it true that from this smartphones can explode? What is the difference between Qualcomm Quick Charge and MediaTek Pump Express, and which is better? And how does fast charge work?  Today there are several standards for fast charging. Many brands in the smartphone market are trying to create their standard, both well-known and unknown Chinese companies. Huawei has its super charge with a maximum power of 22 watts, Asus Bust Master allows you to charge devices under 9 volts and 2 amps current, Samsung developed similar Adaptive Fast Charging technology, it can produce 5 or 9 volts and 2 or 1.67 amps respectively.

How fast charging works?
Any fast charging is based on the principle of increasing the power of the current transmitted to the batteries. But the increase in power in each of these technologies is achieved in different ways. This can be an increase in voltage up to 20 volts, and somewhere they increase the current to 5-6 amperes, and someone combines these methods and increases both the voltage and the current. Recall that electrical power can be determined by multiplying the voltage value in volts by the current in amperes.
P = U ∙ I

All fast charge technologies include:
  • smart controller, most often it is embedded in the processor
  • special charger capable of delivering the required current
  • powerful cable capable of transmitting high power current

Harm from Fast Charging
And yet the first question is whether fast charging is harmful to the battery. And here the situation is ambiguous. There are a number of studies that prove the negative impact of fast charging on a battery, but there are also studies that completely refute this.

Modern lithium-ion and lithium-polymer batteries do not matter with what current strength and voltage they will be charged. If you take a laptop, then they have all the same lithium-ion batteries, only more. But if you look at the parameters of the charger, you will see a current of around 4-5 amps and a voltage of about 20 volts, while the most evil fast charge technologies give out 12 volts and 2-3 amps and that during the first 15-20 minutes, after which they switch to a smaller current.

But it is also true that smartphones from fast charging can explode. The most damaging effect on the battery is heating, it is he who kills the battery and reduces its capacity.

Overheating is the main cause of fire and explosions. All modern technologies of fast charge are equipped with a huge number of systems to protect against overheating, but why do new photos of burnt devices appear on the network? Because no system can protect the gadget from the impact of the user who charges the device with anything and how horrible.

Therefore, never save on chargers and cables. Ideally, always charge your smartphone with the original charger and cable, do not put a damaged device on it. If the body of the smartphone is bent, cracked or broken, it is better not to risk it and not to use such a device at all. Never leave a charging smartphone covered with something, in a tight case or bag.

The second reason for the breakdown of gadgets is poor-quality components or marriage. If you buy a phone for $ 50, then you should not hope that it has a good battery. But there are shortcomings and top brands. You can recall the sensational story about the exploding Galaxy Note 7.

Technology comparison
Now let's look at 3 promising fast charging technologies. This is Qualcomm Quick Charge, slightly less common pump express from MediaTek and found only in Oppa devices VOOC Flash Charge technology.

Oppa vooc flash charge
Let's start with Super VOOC Flash Charge. This, though less common, but the most interesting, the fastest and most careful technology.

At the moment, Oppo has introduced the second version of this technology. It allows you to fully charge the battery at 2500 mAh in 15 minutes, and in 5 minutes the battery can be replenished by 45%, while the smartphone is charged with a completely standard voltage of 5 volts.

This voltage allows you to not heat the battery. These results were obtained through the use of special batteries that withstand current up to 4.5 amperes, which is almost 2 times more than in standard charging. Batteries have eight contacts at once and are divided into several cells that are charged in parallel. Oppo is said to have transferred technology to OnePlus, and she tried to develop her own version of Dash Charge based on VOOC Charge.
MediaTek Pump Express
Next fast charge pump express. It does not greatly depend on the specific batteries and materials from which the connectors and cables are made.
Today's current Pump Express 3.0 charges batteries from 0 to 70% in just 20 minutes. The technology uses a voltage of 3 volts with a current of more than 5 amps. With Pump Express, you can charge the battery directly, bypassing the intermediate circuits, without affecting the standard built-in charging circuit. But this option is only possible when using the USB Type-C connector, because it allows you to greatly reduce energy leakage and reduce heating. To protect against overheating, there are 20 built-in protection systems.

The first processor with Pump Express 3.0 support is Helio P20, it is stated that subsequent chipsets will also receive support for this standard. MediaTek sells its processors in bulk to any smartphone maker, so Pump Express should be found in many MediaTek smartphones, but in practice this is not the case. Why?

Yes, because the processor supports fast charging, but manufacturers do not realize this opportunity, due to the fact that they do not want to develop complicated power circuits for the needs of Pump Express and thereby increase the cost of the device. Perhaps manufacturers fear for the safety of batteries, which are not always made with high-quality budget phones. Of the smartphones made on MediaTek, only a few have fast charging technology.

Qualcomm Quick Charge
Qualcomm has achieved the greatest success in developing fast charging. The development of the Quick Charge technology has been going on for 4 generations and has been brought to the ideal.

All versions are backward compatible, that is, you can use version 4 of the charger with a phone that supports only version 1, in which case charging will switch to Quick Charge 1.0 mode.

Qualcomm's standard supports a huge number of manufacturers of smartphones and accessories. For example, Samsung retains support for Quick Charge, despite the fact that it has its own design. The first version of the Qualcomm standard introduced back in 2013, since the implementation of Quick Charge has not changed much. Integration into a mobile device occurs through a separate chip or together with a Snapdragon chip (central processor) and a special adapter that can deliver high-power current.

With each new version of the standard Quick Charge is becoming faster, smarter and safer. For example, the first generation could charge devices only at 5 volts and 2-2.5 amperes, the second generation allowed to use overvoltage up to 12 volts, or rather the controller chose the required value from three fixed at 5V / 9V / 12V with a maximum current of 3 amperes. In this case, the allowable maximum power of the power supply can reach 18 watts. But with such power, problems with heating began to appear acutely and in the next versions of the standard, engineers paid more attention to protecting the battery from overheating.

The main innovation of Quick Charge 3.0 is not the increased charging speed, but the ability of the technology to save energy, while avoiding excessive heat generation. Implementing this approach allowed the new technology INOV, that is, a smart definition of the desired voltage. Thanks to this innovation, data is being exchanged between charging and the device, when there is a request for the required voltage, which can be any in the range from 3.2 to 20 volts in 0.2 volt increments. Thus, Quick Charge 3.0 allows you to dynamically tune to the required voltage.

As the battery charges or heats up, the controller gradually reduces the voltage required. Including for this reason, the last 20% charge longer. As a result, charging is done carefully, the battery does not overheat, and its wear is minimized. And last year devices with support for Quick Charge 4.0 appeared, the technology is implemented in the Snapdragon 835 chip. The new standard adds several degrees of protection against overheating, there is a built-in cable quality control system that will not allow the device to charge from a poor-quality or damaged wire. But the main novelty in Quick Charge 4.0 will be support for the USB Power Delivery standard. This is a fast charging technology developed by Google. Perhaps in the future PD will become the basis for combining different standards of fast charging, it would be good to use one charge for any standard.

The development of mobile power sources!
What will happen in the future? I want to believe that all smartphone batteries will be based on Graphene, such batteries can boast the properties of super capacitors, and they will take minutes to charge. They are much cooler than modern lithium-ion batteries, do not lose their capacity even after 2000 charging cycles, and have a higher energy storage density. Perhaps such batteries will appear in 10 years, and we will switch to them, the prototypes are already there. And there are still developments on the manufacture of microscopic batteries based on radioactive elements. They do not have to be charged at all, you just need to change them every 2 years, but these are developments of the distant future.

Thanks to Administrator and SMod and Mod!

Related thread:
[How it Works #4] Type of Touchscreen and How it Work!
[How it Works #5] Type of Display and How it Work!
[How it Works #6] Camera in smartphone, and how it works!

[How it Works #7] What is the battery in your phone or smartphone?
[How it Works #8] What is a processor in a mobile phone?
[How it Works #9] What is a RAM in smartphone!
[How it Works #10] How to produce processors, and what are the difficulties in their manufacture!
[How it Works #11] What is a Modem in a Mobile Phone?


Number of participants 4 Experience +51 Pack Reason

View Rating Log

2019-07-02 02:52:51
Favorites33 RateRate

Grand Master Bunny

Seragios | from Redmi 5


Thanks for sharing information ❤️❤️❤️
2019-07-02 03:00:07

Intern Moderator

BeingBishal | from MI 9 SE


Nicely Explained!
2019-07-02 03:15:28

Beta Team-Global

Animesh Singh | from Redmi Note 6 Pro


Good information sharing, Thanks
2019-07-02 03:35:56

Photography Team

Jillzy | from Redmi Note 5


nice-nice , thanks for information!
2019-07-02 04:05:44

Master Bunny

NDaru.NDGOLL | from Redmi 5 Plus


Thank you for sharing,nice information
2019-07-02 04:10:28

Beta Team-Global

NEAR_MI | from Redmi Note 6 Pro


Thanks for sharing
2019-07-02 05:33:30

Advanced Bunny

shaunmoroz | from Redmi Note 7


Excellent explanation! Glad my Redmi Note 7 has QC4. ;)
2019-07-02 07:37:21

Device team

$huvo | from Redmi 4


Thanks for sharing
2019-07-02 08:15:45

Beta Team-Global

georan. | from Redmi Note 5 Pro


thanks to share
2019-07-02 08:31:04

News Reporter

ᎮᏒᎥᏁፈᏋ | from Redmi Note 4X


Well Explained thanks for sharing
2019-07-02 10:04:05
please sign in to reply.
Sign In Sign Up


Super moderator

  • Followers


  • Threads


  • Replies


  • Points


3 Days Check-In
7 Days Check-In
21 Days Check-In
40 Days Check-In
70 Days Check-In
Newbie Member
100 Коментарів
100 Тем
New Home
10k Mi Fans
Redmi Note 7
Cast Away
20K Mi Fans
Mi Love U & I
Bunny Winner
20K Mi Fans
Best Mi
Android Q
50K Mi Fans
Mobile Photography Lover
70K Mi Fans
Eid ul-Fitr Mubarak
Brain Teaser
100K Mi Fans
Selfie Day
Mi 9T
Global Fans
My Country My Pride
Check in
Profile Medal
MIUI 9th Birthday

Read moreGet new
Copyright©2016-2019, All Rights Reserved
Content Policy
Quick Reply To Top Return to the list