What fast charging

I. Definition of Fast Charging What is fast charging? Is it judged by power? Is voltage the criterion? Is the interface the criterion? This has to be considered comprehensively. At present, there is no clear judgment on the definition of fast charging by relevant organizations, and everyone has their own understanding of fast charging. Fast is different from slow, and reference can be used as a basis for judgment. USB standard supply voltage 5V, iPhone 11 uses Apple 5V1A 5 W charging, which is definitely classified as slow charging, while using APPLE2.4A protocol to achieve 12 W charging power, or using USB-C to Lightning to obtain more than 18 W power through PD charger, both of which are fast charging. In terms of Android formation, raising voltage through QC can also be included in fast charging, VOOC, SCP and other changes in low voltage and high current are also fast charging, and PD super power charging is also fast charging. Simply put, the methods of increasing charging power by different means can be summarized as fast charging. Two, when did the fast charging come out? As early as the Nokia era, electronic products mostly used the method of battery replacement to maintain their battery life. At that time, electronic products had a single function and low power consumption. A battery could be used for several days. It was normal to take several batteries with extended battery life. It can be said that there was no demand for fast charging in the market at that time. Until Samsung note giant screen mobile phone came on the market, the matching charger first appeared strange specifications, the output voltage was not 5V but 5.3 V, and with line loss compensation function to offset the voltage drop loss of wires to improve charging power, at this time, users found that the charging speed of this charger was much faster than other 5V chargers, with a comparison of speed and speed. So for the first time, the experience of "fast charging" was vaguely born. In 2014, OPPO launched Find7 mobile phone with VOOC flash charging, charging for five minutes and talking for two hours, but only OPPO users enjoy this pleasure. In 2015, a large number of Qualcomm QC2.0 mobile phones were launched. Based on the general technical standards and a variety of third-party accessories, fast charging officially began, and most users enjoyed the fun of fast charging for the first time. Three, USB-C unified to promote the development of PD fast charging As early as December 2013, the USB-if Association of the United States announced the USB-C interface, and then the relevant industry chain began to prepare for mass production in 2014. The USB-C interface supports double-sided blind insertion, which solves the experience of observing the positive and negative reinsertion with the naked eye at the device end. Up to 24pin enables the interface to support 100 W power transmission and 20Gbps data transmission, and the PPS voltage subset has been added to the later PD3.0 standard, which has the potential for sustainable development. In 2015, many products equipped with USB-C were born for the first time, such as the first USB-C mobile phone Le Superphone 1, the first USB-C notebook New Macbook, the first tablet Nokia N1, the first usb-c charger Apple 29W, and the first usb-c charger Yubo YB-CP1. These pioneers have promoted the rapid popularization of USB PD in the future. The great unification of USB-C interface makes the industry full of vitality, and all kinds of PD fast charging accessories are inexpensive. After several years of market development, USB PD fast charging has entered almost all mainstream electronic products in 2020. IV. Composition of fast charging system The fast charging system consists of three parts, the charger (power adapter) responsible for providing power, the cable (data line) for power transmission, and the receiving end equipment (digital products), each of which is a participant in the fast charging system. 1. Quick charger In the past, because of different voltage requirements and different interfaces, each device needed a corresponding charger, and the plugboard was densely filled with different chargers. Nowadays, the advanced communication mechanism of USB PD allows different devices to communicate with the charger and ask for the matching voltage of their own needs. Whether it is a high-power notebook up to 100 W or a TWS headset with only a few watts, they can use the same PD charger to charge, and the multi-port charger can also provide one-to-many services. From the device point of view, the traditional silicon-based charger is huge and inconvenient to carry. In order to reduce the size of the charger, the switching frequency must be increased. However, the traditional silicon-based semiconductor can not meet the high frequency characteristics, so the charger volume has been maintained at a large level. In 2018, ANKER successfully mass-produced the first gallium nitride charger, announcing that the charger has entered another dimension. Gallium nitride charger with high frequency and high efficiency can use smaller transformers, capacitors, inductors and other devices, coupled with three-dimensional stacking design, the volume of gallium nitride charger is nearly half smaller than that of traditional charger under the same power. 2. Fast charging cable In addition to the charger, fast charging also requires the use of data lines, which are mainly divided into USB-C to USB -C, USB-C to Lightning, and USB-C to USB -a. USB-C to USB-C is also known as CC cable, which can be divided into 60 W power transmission wire and 100 W power transmission wire according to the wire specification and whether it is equipped with 5A E-Marker chip. If users need more than 3A current, they must use it with 5A E-Marker wire. CC wire has become the most common wire for Android mobile phones, tablets and notebooks. USB-C to Lightning is a special wire used by Apple to connect to the PD charger. The applicable devices include iPhone, AirPods, low-end iPad and other Apple devices. As a Lightning wire, each one needs to pass the MFi certification. There are two types of USB-C to USB. One is special specification, which is mainly used for some special fast charging equipment, such as Huawei low voltage fast charging SCP, such as OPPO series low voltage fast charging VOOC, and such as Xiaomi private magic modification fast charging. The other is general wire, which does not support PD fast charging and only supports QC