Explainers

What exactly is Fast Charging? And how does it work?

Published

June 5, 2017

Martin James David

The mention of fast charging technologies for smartphones has become quite common lately. You’ve probably already heard of Qualcomm’s Quick Charge, OPPO’s VOOC flash charge, or OnePlus’ Dash Charge, which can juice up a smartphone’s battery to around 60 percent in just 30 minutes. So, how exactly do they work?

Most devices use lithium-ion batteries

To understand how these technologies work, knowing the basic principle of how a smartphone’s battery gets charged is a must. Most, if not all, smartphones today use a type of battery called lithium-ion (Li-ion). A Li-ion battery is composed of a positive and negative electrode and an electrolyte in between them. The lithium ions inside the battery move from one electrode to another, allowing the battery to be in a charging (storing energy) or discharging (expending energy) state.

The direction of lithium ions determines whether a battery is charging (positive to negative) or discharging (negative to positive).

Battery capacity is measured in milliampere hour (mAh)

Great, we’ve got some background on how Li-ion batteries work! The next question is how exactly do we determine the speed at which a Li-ion battery gets charged. You’re probably familiar with the rating used to gauge the capacity of a smartphone’s battery. If not, it’s the number that uses mAh (milliampere hour) as its unit of measurement. A larger number means larger capacity, which translates to longer battery life.

A 6000mAh battery will last twice as long as a 3000mAh battery. The same thing applies to charging: The larger the capacity of a Li-ion battery, the longer it takes to fully charge. The amount of current that the charger can output is usually the determining factor on how fast a battery can be charged, which is why a tablet charger that can output 2A (ampere) will charge twice as fast as a smartphone charger that can output 1A.

Another important nature of a Li-ion battery is that it doesn’t charge in a linear fashion. It’s easier to charge the battery when it’s nearly empty compared to charging when it’s nearly full. Think of it like packing a bag; it gets harder to put things in as it gets filled.

As mentioned, increasing the current used to charge a battery decreases charging time, but only up to a certain point. A Li-ion battery can only take in so much current, and increasing it past the threshold only results in dissipated energy in the form of heat. Therefore, if you use a tablet charger to charge a smartphone, it usually charges faster but also heats up faster.

Battery charging has evolved through the years

With all these things in mind, we can go back to the question of how fast charging technologies work. As its name implies, it allows rapid charging of a smartphone’s battery. This is usually done by increasing the power output of a charger, either by increasing the voltage or current that it provides to the device. You might ask if it’s safe to increase the amount of power we pump into our devices: Theoretically, it isn’t safe, but with the right hardware for monitoring and checking power output and temperature, things become safer.

Smartphones nowadays are smart when it comes to charging. Most devices today have a built-in chip for monitoring battery temperatures and the amount of power going through as the phone charges. This allows the smartphone to intelligently lessen or stop receiving power from the charger once the battery is full or if the battery gets too hot. That’s why when you leave your phone to charge, you’ll notice the charger and the battery heat up while charging, and once they’re done, both will stop heating up.

Taking things further are these new fast charging technologies that can provide more than half of a battery’s capacity in less than an hour. They work by pushing as much power as the device can handle to ensure the battery is charging at its maximum rate. As mentioned earlier, when a battery is at a low capacity, it’s easier to charge since the lithium ions have more freedom to move. This nature is what Qualcomm and other manufacturers take advantage of for faster charging.

Qualcomm’s Quick Charge gets better every year

Qualcomm’s Quick Charge technology leverages on different power outputs — mostly voltage adjustments — for the charger, depending on the current battery capacity of the device. Thanks to the special chip installed on both the device and charger, the latter can actively adjust the power output depending on the device’s needs. So, at lower capacities, it delivers the highest power rating the device can safely handle, and as the battery gets more juice, the device communicates with the charger and tells it to provide less power.

Ever since Quick Charge was introduced, Qualcomm has continued its development and currently has five iterations: Quick Charge 1.0, 2.0, 3.0, 4.0, and just recently, 4+. Here’s a table to summarize what the first four iterations of Quick Charge are capable of:

Quick Charge Version	Voltage	Current	Power (Watts)
1.0	5V	2A	Up to 10W
2.0	5V, 9V, 12V	2A, 2A, 1.67A	Up to 18W
3.0	From 3.2V to 20V, dynamic increments of 200mV	2.6A, 4.6A	Up to 18W
4.0	Dynamic	Dynamic	Up to 28W

Quick Charge 4.0 builds on the success of QC 3.0 by adding new features: compliance to USB Type-C and USB Power Delivery; a newer version of Intelligent Negotiation for Optimum Voltage (INOV), allowing the device to determine the optimum power level to request from the charger; and the inclusion of Dual Charge which adds a secondary power management chip in the device for better thermal dissipation and more efficient charging.

Even though few smartphones supporting QC 4.0 have been released, Qualcomm has already launched an update, version 4.0+. It further improves the Dual Charge feature of its predecessor with the addition of Intelligent Thermal Balancing, which eliminates hot spots by moving current through the coolest path available during charging. Building on the already robust safety features of QC 4.0, this update goes one step further by also monitoring the temperature levels of the case and connector. The added layer of protection helps prevent overheating and short-circuit damage.

High-current charging for OPPO and OnePlus

Being sister companies, OPPO’s VOOC charging technology and OnePlus’s Dash Charge have the same method for charging faster, and they do so by providing high amounts of current (around 4A) while charging. The level gets lower as the device gets charged up. Again, thanks to the special chips installed in the device and charger, OPPO and OnePlus devices supporting these technologies can charge faster.

Quick Charge and VOOC/Dash Charge may both be fast charging technologies, but they have some differences. Quick Charge mainly leverages on the use of higher voltages, while VOOC and Dash Charge use high-current charging. OPPO and OnePlus also made sure that the charger takes in the bulk of the heat generated while charging, which is not the case for Qualcomm’s Quick Charge, wherein both the charger and the device heat up.

Because of the phone not heating up too much, OPPO and OnePlus devices can be used while fast charging without any issues. In addition, OPPO and OnePlus’ fast charging technology is proprietary, which means you’ll need the charger and cable that came with your device to use it.

Samsung has its own Adaptive Fast Charging technology

If you own a recent Samsung device, you’re probably familiar with Adaptive Fast Charging. This is essentially the same as Qualcomm’s Quick Charge technology, since Samsung acquired the license from Qualcomm to use its technology on devices that have non-Qualcomm processors. This means a Quick Charge adapter can be used on a Samsung device that features Adaptive Fast Charging and vice versa.

Fast Charging requires specific hardware

Keep in mind that to make use of such tech, you’ll need a smartphone that supports a fast charging technology and a certified charger and/or cable. If you’re using a higher-end phone that’s been released in the last couple of years, chances are your handset supports fast charging.

Summing thing up: Fast, quick, rapid charging, or whatever they call it, is technically just a smarter form of charging that takes advantage of how Li-ion batteries work. With all the prerequisites — a compatible smartphone and charger — you won’t be stuck near a wall outlet for a few hours just to receive an ample amount of energy in your device. Until better battery technology comes out, fast charging might be the only solution we have for a while.

Illustrations: Kimchi Lee

[irp posts=”9952″ name=”Why is USB Type-C so important?”]

Explainers

Everyone’s angry at PlayStation’s new no-disc policy, and this is why

It’s a tragedy for nostalgia, ownership, and preservation.

Published

July 2, 2026

Luigi Leonardo

Check in with your gamer friends today. Today, a lot of gamers are up in arms over Sony’s decision to kill the physical game disc starting in 2028. But, if you’re a digital-only gamer or just not a gamer yourself, you might not understand the anger. If you want to understand the ire or just want to relate with your gamer friends, here’s a primer for you.

Ending the era of the physical media

Last year, Nintendo launched the Switch 2. Though the console still has a slot for physical cartridges, the Switch 2 also introduced the Virtual Game Card as a way to digitize your library of games.

Of course, the feature wasn’t positioned as a way to eliminate physical cartridges. In fact, Nintendo just wanted to add the flexibility of physical cartridges to the digital world. In the end, the feature strangely coincided with less cartridges. For example, Pokémon Pokopia, one of the most popular games this year, does not come with a cartridge even if you buy a “physical” copy in a brick-and-mortar store. It was a portent of things to come.

Fast forward to today, Sony has made the monumental decision to stop producing physical game discs starting in 2028. The PlayStation’s future is completely digital.

On a similar note, Microsoft is also experimenting with a disc-to-digital feature. Much like the Nintendo Virtual Game Card, the experiment will digitize libraries and attaches the digital copy to the physical game disc. It sounds awfully like a prelude to killing off the game disc.

Why this matters

The physical disc is synonymous with a simpler time. It represents a time when gamers camped out stores to anticipate midnight releases, when gamers can learn more about their games through an in-box manual, and when gamers can show off their fandom through a beautifully stocked shelf of games.

And yes, that’s part of why this situation sucks, but it’s not the only reason.

If you’re an outsider looking in, this nostalgia factor is the easiest to see. Then again, it’s also the most difficult to relate with, especially if you’ve never had the history of buying physical games.

The more crucial reason — and the one that most people will relate with — is media ownership. By not having a physical copy, you will no longer have ownership of what you bought digitally.

And it’s not an imaginary issue. In 2024, Steam amended its policies to reflect that players do not own the games they buy. Rather, they simply own a license to play the game.

In the same year, Ubisoft delisted The Crew, a sure sign that the new policy means business. Though Steam itself has a relatively good track record of prioritizing its customers, publishers and developers can get rid of games if they choose to.

That limitation doesn’t exist with a physical copy. As long as you have a working disc drive, you can install a game whenever you want, even if the publisher decides to pull it from stores.

Therein lies how much this is a touchy topic. Should you own digital goods in the same way as you own physical ones? If the answer is yes, then selling only the license for the good doesn’t make sense. But if it’s a no, we shouldn’t pay full price for something we don’t own anyway.

Will PlayStation actually delete games?

Now, just because they can, does it mean that they will?

Right now, it’s hard to say. You can certainly go by the optimistic hope that PlayStation would never do something as anti-consumer as that. And yes, there are times when you’d be right.

Plus, there is a good chance that governments, especially those in the European Union, will protect consumers if PlayStation even thinks about deleting a game that others have paid for. Governments have been known to intervene in the past, such as when the EU forced Apple to adopt USB-C as a standard. There are checks and balances available.

Then again, Sony has had recent history of deleting media from a user’s library.

Only a few days ago, PlayStation made headlines for deleting over 500 titles from their library. Starting September 1, users can no longer access movies distributed by Studio Canal, due to licensing agreements. Sony was unapologetic about unceremoniously deleting this content. No refunds, no apologies; just 500 movies, which you thought you bought, gone for good.

No matter how you angle it, Sony’s recent decisions just don’t bode well for media ownership.

You can argue that this is the price we’re paying for not buying enough physical games. Still, losing PlayStation discs, even as an option, is tragic for nostalgia, ownership, and preservation.

The world we live in

Unfortunately, this all comes with precedent. Unless you buy physical games and movies, we already don’t own anything in today’s world.

Outside games, Netflix and Disney+ remove the ownership of movies and shows from us. It’s already common practice for these platforms to remove titles regularly. Some platforms even give you a last chance to catch these titles before they go away. Moreover, they can even restrict access, like with Disney+, if you travel abroad.

In exchange for convenience, subscription services and digital storefronts have made it all too comfortable to not own media. With a rental service like Netflix, that’s all expected, but we’re now at the inevitable stage when even bought games and movies are at the behest of our corporate overlords.

This is where the fury comes from. Companies are getting more brazen about taking more options from us. Between this and the increasing prices of RAM, it’s getting harder and harder to live as a tech-savvy citizen in today’s age.

Computers

Samsung’s SECRET That Made OLED Even Better

Say hello to the new QD-OLED Penta Tandem display tech by the Korean giant

Published

May 23, 2026

GadgetMatch and Michael Josh Villanueva

Samsung Display just unveiled QD-OLED Penta Tandem technology. This is a next-generation display structure that stacks five emission layers to improve brightness, efficiency, and overall OLED performance.

In this video, we simplify what Penta Tandem actually is, how it works, and show you two monitors that already have the technology — specifically from MSI and Dell.

For more details, check out Samsung Display here.