Quick Charge (QC) is a proprietarybattery charging protocol developed byQualcomm, used for managing power delivered overUSB, mainly by communicating to the power supply and negotiating a voltage.
Quick Charge is used by devices such as mobile phones which run on Qualcommsystem-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 andregulating the incoming voltage internally. Many chargers that implement Quick Charge 2.0 and later are wall adaptors, but it is implemented on somein-car chargers, and somepower banks use it to both receive and deliver charge.
Quick Charge is also used by other manufacturers' proprietary rapid-charging systems.
Quick Charge is a proprietary technology that can charge battery-powered devices, primarily mobile phones, at power levels exceeding the 7.5watts (5 volts at 1.5 amps) possible in the USB BC 1.2 standard, using existingUSB 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 lessresistive loss, which becomes significant for longer cables.
Numerous other companies have competing technologies, includingMediaTekPump Express andOPPO VOOC (licensed toOnePlus asDash Charge), the latter of which supplies higher current without voltage increase, relying on thicker USB wires to handle the current withoutoverheating, as described inVOOC § Technology.[1]
Circuit board to simulate QuickCharge voltage request signals
Though not publicly documented, the voltage negotiation between device and charger has beenreverse-engineered, and a custom voltage can be manually requested from the charger using atrigger circuit that simulates the negotiation to an end device.[2][3]
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),[4] using twoPMICs to split the power into 2 streams to reduce phone temperature.[5]
Quick Charge 3.0 introducedINOV (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.[6] 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.[4]
Quick Charge 4 was announced in December 2016 for theSnapdragon 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 bothUSB-C andUSB-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.[7] 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+.[5]
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.[8][9]
Quick Charge 5 was announced on July 27, 2020.[10] With up to 100W of power, on a mobile phone with a 4500mAh battery, Qualcomm claims 50% charge in just 5 minutes. Qualcomm announced that this standard is cross-compatible withUSB PD PPS programmable power supply, 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 8.8V; the dual cell can then ask thePPS 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 theXiaomi Mi 10 Ultra.[11]
On February 25, 2019, Qualcomm announced Quick Charge for Wireless Power. Quick Charge for Wireless Power falls back on theQi standard by theWireless Power Consortium if either the charger or device is not compatible.[12]
^Some mobile phones deactivate fast charging during operation, and only activate fast charging duringstandby mode or power-off state.
^TheGalaxy Note 4, released in September 2014, was already equipped with Quick Charge 2.0.[16]
^Because Quick Charge 3.0 power supplies are backwards-compatible with Quick Charge 2.0, Quick Charge 3.0 chargers are often able to deliver more power to Quick Charge 2.0 loads than Quick Charge 2.0 chargers, since Quick Charge 3.0 chargers can provide higher currents at the same voltages.
^Samsung's own 15W Quick Charge 2.0 mobile phone chargers can produce only 5 and 9 volts (at 2A and 1.67A respectively), not 12 volts (at which 1.25A is possible in some other 15W Quick Charge 2.0 chargers).[36][37]
