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Fast Charger: The Difference Between QC3.0 And QC2.0
Mar 31, 2018

With the development of science and technology, the functions of mobile phones, tablets and other devices are becoming more and more powerful, and the power that comes with them is also consumed very quickly. Therefore, more and more people are pursuing fast charging, and then quick chargers are gradually emerging on the market. So what is a quick charger? QuickCharge (herein after referred to as QC) is a fast charging technology dominated by Qualcomm and has now been developed to the latest QC3.0 version. Although QC3.0 has higher charging efficiency, its popularization process is not as smooth as it should have been.


Fast charger

QC3.0 new features

Compared with the VOOCs of MediaTek Pump Express Plus (hereinafter referred to as PEP) and OPPO, Qualcomm QC fast charging technology has the highest share in the field of smartphones. Taking QC 2.0, which is becoming popular, as an example, the Class A standard customized for smart phones supports 5V, 9V, and 12V input voltages, and can achieve up to 24W of charging power on the premise of 2A input current.


QuickCharge 2.0/3.0 has two standards, Class A and Class B. Among them, ClassA standard QC2.0 supports three voltages of 5V/9V/12V, QC3.0 supports 3.6V to 12V fluctuation voltage; Class B standard QC2.0 supports four voltages of 5V/9V/12V/20V, QC3.0 supports 3.6V to 20V fluctuation voltage. As the smart phone field does not use the exaggerated 20V voltage, its peripheral chargers and mobile power QC2.0/3.0 are based on the Class A standard. At this stage, the chips that have announced support for QC 3.0 include Xiaolong 820, Xiaolong 620, Xiaolong 618, Xiaolong 617 and Xiaolong 430.

Unfortunately, QC2.0's "fixed voltage" management mechanism is too simple and rude. After judging that both the mobile phone and the charger support QC2.0, it will directly jump the input voltage from 5V to 9V or 12V and rush to the total power. The 90% (this standard can be customized by the manufacturer), and then add to 100% of the electricity through trickle charging. This will lead to a problem: When the 9V/12V fast charge, the battery voltage and the DC / DC converter circuit input and output voltage difference is greater, so the power consumption is more serious and brings the problem of cell phone fever. For this reason, the vast majority of mobile phone manufacturers will choose to reduce the input current to control the heating problem to a reasonable range, such as a QC2.0 charger supporting 5V/2A, 9V/1.8A, 12V/1.5A. Relieve from the side.

The biggest improvement of QC3.0 is to replace the "fixed voltage" management mechanism with "INOV" (Intelligent Negotiation for Optimum Voltage), allowing the input voltage to start from 3.6V to 0.2V (200mV). For units, fine-tune in conjunction with real-time battery temperature, conversion efficiency, power and other factors, and gradually increase or decrease within the allowable input voltage range (9V or 12V), unlike QC2.0 only at 5V/9V/12V The "non-one to two" violence choices were made.

With the help of the “INOV” management mechanism, QC3.0 can significantly reduce the loss of the DC/DC conversion circuit, which effectively alleviates the heating problem during fast charging. According to Qualcomm, QC3.0 can achieve a 38% increase in efficiency over QC2.0, a 27% increase in charging speed, a 45% reduction in heat, and a typical cell phone charging from zero to 80% in approximately 35 minutes. However, is the fact really as good as Qualcomm imagined?