science

Quick Charge

Quick Charge is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Quick Charge rather than just read about it. In short: Quick Charge (QC) is a proprietary battery charging protocol developed by Qualcomm, used for managing power delivered over USB, mainly by communicating to the power supply and negotiating a voltage. Quick Charge is used by devices such as mobile phones which run on Qualcomm system-on-chip (SoCs), and by some chargers; both device and charger must implement QC for QC charging to happen; if one doesn't implement it, r…

Key takeaways

Quick Charge belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Quick Charge to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Quick Charge from memory before moving on to harder problems.

Reference excerpt

Quick Charge (QC) is a proprietary battery charging protocol developed by Qualcomm, used for managing power delivered over USB, mainly by communicating to the power supply and negotiating a voltage. Quick Charge is used by devices such as mobile phones which run on Qualcomm system-on-chip (SoCs), and by some chargers; both device and charger must implement QC for QC charging to happen; if one doesn't implement it, regular USB charging happens. QC charges batteries in devices faster than standard USB allows by increasing the output voltage supplied by the USB charger, while adopting techniques to prevent the battery damage caused by uncontrolled fast charging and regulating the incoming voltage internally. Many chargers that implement Quick Charge 2.0 and later are wall adaptors, but it is implemented on some in-car chargers, and some power banks use it to both receive and deliver charge. Quick Charge is also used by other manufacturers' proprietary rapid-charging systems.

Details Quick Charge is a proprietary technology that can charge battery-powered devices, primarily mobile phones, at power levels exceeding the 7.5 watts (5 volts at 1.5 amps) possible in the USB BC 1.2 standard, using existing USB cables. The higher voltage available allows more power (watts) to be supplied through wires without excessive heating. As current is lower for the same power if voltage is increased, there is less resistive loss, which becomes significant for longer cables. Numerous other companies have competing technologies, including MediaTek Pump Express and OPPO VOOC (licensed to OnePlus as Dash Charge), the latter of which supplies higher current without voltage increase, relying on thicker USB wires to handle the current without overheating, as described in VOOC § Technology.

Though not publicly documented, the voltage negotiation between device and charger has been reverse-engineered, and a custom voltage can be manually requested from the charger using a trigger circuit that simulates the negotiation to an end device. For Quick Charge charging to happen, both the power supply and the device being charged must implement it; otherwise charging falls back to the standard USB ten watts. Quick Charge 2.0 introduced an optional feature called Dual Charge (initially called Parallel Charging), using two PMICs to split the power into 2 streams to reduce phone temperature. Quick Charge 3.0 introduced INOV (Intelligent Negotiation for Optimal Voltage), Battery Saver Technologies, HVDCP+, and optional Dual Charge+. INOV is an algorithm that determines the optimum power transfer while maximizing efficiency. Battery Saver Technologies aims to maintain at least 80% of the battery's original charge capacity after 500 charge cycles. Qualcomm claims Quick Charge 3.0 is up to 4–6 °C cooler, 16% faster and 38% more efficient than Quick Charge 2.0, and that Quick Charge 3.0 with Dual Charge+ is up to 7–8 °C cooler, 27% faster and 45% more efficient than Quick Charge 2.0 with Dual Charge. Quick Charge 4 was announced in December 2016 for the Snapdragon 835 and later chips. Quick Charge 4 implements HVDCP++, optional Dual Charge++, INOV 3.0, and Battery Saver Technologies 2. It is cross-compatible with both USB-C and USB-PD specifications, with fallback to USB-PD if either the charger or device is not QC-compatible. However, Quick Charge 4 chargers are not backward compatible with Quick Charge. It also features additional safety measures to protect against over-voltage, over-current and overheating, as well as cable quality detection. Qualcomm claims Quick Charge 4 with Dual Charge++ is up to 5 °C cooler, 20% faster and 30% more efficient than Quick Charge 3.0 with Dual Charge+. Quick Charge 4+ was announced on June 1, 2017. It introduces Intelligent Thermal Balancing and Advanced Safety Features to eliminate hot spots and protect against overheating and short-circuit or damage to the USB-C connector. Dual Charge++ is mandatory, while in prior versions Dual Charge was optional. Unlike Quick Charge 4, Quick Charge 4+ is fully backward compatible with Quick Charge C 2.0 and 3.0 devices. Quick Charge 5 was announced on 27 July 2020. With up to 100 W of power, on a mobile phone with a 4500 mAh battery, Qualcomm claims 50% charge in just 5 minutes. Qualcomm announced that this standard is cross-compatible with USB Power Delivery plus Programmable Power Supply (USB PD PPS), and that its technology can communicate with the charger when charging double cells and double the voltage and current out. For instance, a single battery requests 8.8 V; the dual cell can then ask the PPS charger to output 17.6 volts and split it in half to the two separate batteries, providing 5.6 amps total to achieve 100 watts. The first phone with this technology was the Xiaomi Mi 10 Ultra. Quick Charge 5+ was announced on Sep 10, 2025.

Quick Charge for Wireless Power On February 25, 2019, Qualcomm announced Quick Charge for Wireless Power. Quick Charge for Wireless Power falls back on the Qi standard by the Wireless Power Consortium if either the charger or device is not compatible.

Versions

Other charging protocols

Compatible with QC-enabled chargers USB Power Delivery (USB-PD, used by multiple brands and platforms) Adaptive Fast Charging (Samsung) Super Fast Charging (Samsung, utilize USB PD PPS) BoostMaster (Asus) Dual-Engine Fast Charging (Vivo, pre-2020 models only) – interchangeable with Dash Charge and VOOC Mi Turbo Charge (Xiaomi) TurboPower (Motorola)

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Quick Charge

Start with the simplest possible case. Write down what Quick Charge claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Quick Charge before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Quick Charge ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Quick Charge

In research: Quick Charge appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Quick Charge in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Quick Charge is common in secondary-school and first-year university syllabi. It links to neighbouring topics Battery chargers, Consumer electronics, Qualcomm, so understanding it makes those chapters shorter.
In everyday life: Look for Quick Charge outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Quick Charge in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Quick Charge means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Quick Charge out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Quick Charge in simple terms?

Why does Quick Charge matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Quick Charge?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Quick Charge.