Which is better for High-current fast charging or high-voltage fast charging?
With the development of mobile phone charging technology, most of the current smartphones adopt fast charging solutions. We are familiar with OPPO VOOC flash charging, Qualcomm QC fast charging, Huawei SuperCharge charging, and so on.
So which one is better, high-voltage fast charging or high-current fast charging?
According to power P=current (I) x voltage (U), increasing the charging power of the mobile phone is nothing more than increasing the charging current or increasing the charging voltage, or both.
At present, fast charging includes high voltage fast charging and high current fast charging. The representative of high voltage fast charging is Qualcomm QuickCharge fast charging technology. Qualcomm finally gave out QC 4+ fast charging head at the second Snapdragon Technology Summit not long ago. It can be seen from the parameters that Qualcomm QC 4+ supports fast charging up to 27W. The output power is 5V/3A, 9V/3A, 11V/2.4A, 12V/2.25A. From the technical parameters, Qualcomm QC 4+ is still high-voltage and fast. For the charging scheme, the maximum current does not exceed 3A.
Qualcomm’s QC 4+ is one of the few fast charging solutions that still insists on high-voltage fast charging. Which one is better? The low-voltage and high-current fast charging solutions are better. The most obvious daily experience is fast charging. At the same time, charging heat is also low.
The voltage of low-voltage and high-current fast charging is mostly around 5V, and the voltage of the mobile phone battery matches this data. Therefore, the power conversion efficiency is higher when charging the mobile phone with low-voltage and high-current.
Because most of the energy loss in the charging process is on heat generation, the lower the heat generation, the higher the conversion efficiency. However, the high-voltage fast charging scheme does not have this advantage, and the heat generated during the charging process is significantly higher.
In addition to low-voltage and high-current fast charging and high-voltage fast charging, there are also fast-charging technologies that use a compromise method. The voltage and current are increased a little bit, and the same charging power can also be achieved.
Qualcomm's QuickCharge supports this feature. For example, the latest QC 4+ supports 12V/2.25A fast charging and also has a 9V/3A gear, but even this compromise method is not necessarily the power conversion efficiency. There are low-voltage fast charging and high-speed charging. As for why Qualcomm insists on high-voltage fast charging, I don’t know.
It can be seen from the above that although the names of the fast charging schemes on the market are varied, the real fast charging schemes are actually only high-voltage fast The advantages of low heat generation at the time of the fuselage began to spread gradually.
In the future, with technological breakthroughs, an extremely fast charging solution with high voltage and high current may appear.