The fastest popular Quick Charge protocol is Quick Charge, referred to as QC protocol, launched by qualcomm, the mobile phone chip giant. The original Qualcomm QC1.0 phase upgraded the original 5V1A to 5V2A, doubling the charging power from 5W to 10W. In QC2.0 phase, limited by the maximum current of 2A supported by the MicroUSB interface, Qualcomm chose the high-voltage, low-current mode in the fast charging scheme. QC2.0 breaks the conventional standard output voltage of 5V and increases the voltage to support up to 20V. However, after various considerations, mobile phone manufacturers mostly use 9V,12V high voltage scheme, with 2A current, with 18W or 24W charging power. The advantage of this solution is only need regular charge of charging wire with high pressure head can be used, the problem is when the 12 V electricity at the end of the phone need to be done on the mobile end step-down, fell to 4.2 V battery can accept, in the process of mobile terminal step-down will produce a lot of heat, this is the main reason for the rapid charging fever early mobile phones products. Heating means energy loss, and the conversion rate is only about 80%.
At this time, there is an international association called USB-IF, which is a non-profit organization, they vigorously promote USB Power Delivery, also known as PD protocol. At present, all the mainstream mobile phone manufacturers have supported PD quick charge protocol, including Apple, and some previous charging protocols are backward compatible. In addition, PD protocol uses Type-C as the only designated interface, with a maximum charging power of 20V5A (PD3.0 already supports a maximum charging voltage of 21V), that is, 100W. It can charge laptop computers, game consoles and other devices with only one set of charger. Usb-pd, also known as USB Power Delivery in English, is a fast charging standard launched by THE USB standardization organization USB-IF. After nearly 7 years of development and update, the current USB PD fast charging protocol has developed from the original version 1.0, version 2.0 and version 3.0 to the current PPS. In July 2012, USB-IF released the USB-PD 1.0 standard based on the then ubiquitous USB-A and USB-B interfaces. It depicts the beautiful imagination of USB 3.0 and USB 2.0 ports with up to 100W power supply capacity, but it was not until the advent of USB-C interface that this imagination began to become a reality. In August 2014, USB-IF released the revolutionary Type-C 1.0 interface standard and USB-PD 2.0 standard. At the same time, Qualcomm’s QC 2.0 version was released in the same year. USB PD makes the magic USB Type-C interface not only have the traditional power and data transmission ability, but also have the audio and video transmission ability. In addition, power, data, and audio and video transmission speeds are better than traditional transmission lines. Compared with Micro-USB, USB-C (USB Type-C) interface supports up to 20V 5A power transmission, which is naturally more suitable for fast charging. However, usB-C interface is not the mainstream interface of smart phones at this time, so the third-party quick charging protocol led by Qualcomm QC protocol is still the mainstream of the market. At the end of 2015, USB-IF launched the USB-PD 3.0 standard. However, the quick charge standards on the market are different, such as Qualcomm QC 4.0/3.0, Mediatek PE3.0/2.0, Huawei Super Charge, MOTOROLA Turbo Charge, OPPO VOOC flash charge, OnePlus DASH flash charge, Meizu mCharge and so on. The situation of fast charging market is not significantly improved. In February 2017, the USB-IF organization released a major update to the USB-PD 3.0 standard, adding a Programmable Power Supply (PPS) to the USB-PD 3.0 standard, which aims to provide a unified specification for today’s quick charging solutions. At present, it has realized the collection of Qualcomm QC 3.0/4.0, Mediatek PE 2.0/3.0, OPPO VOOC, Huawei SuperCharge and other standards, which means that it can perfectly support these four fast charging schemes. The USB organization has even reached a consensus with China’s Ministry of Industry and Information Technology tel Laboratory to achieve a unified standard with the NATIONAL standard in the future.
21 v. This is an important change because there are two types of fast charging: high voltage low current and low voltage high current. From 3.0 V21V power supply range, so that PPS can meet a variety of technical schools of quick charging. 2, PPS voltage range can be adjusted to 20mV, can realize low voltage and high current direct charge. The voltage adjustment range of one gear of 20mV makes low-voltage and high-current direct charging possible. In fact, this technology is very controversial, because some phone manufacturers want to implement constant current direct charging control directly on the adapter, rather than on the phone end. But USB-IF did not agree to this after all. The main concern is that the constant current mechanism may cause severe fluctuation of output voltage in some cases, which is not good for the internal Bypass path management and power supply security of the internal baseband module of the mobile phone. 3. PPS has pulsating mechanism to ensure the safety of charging process. Once the PPS enters high current mode, safety becomes very important, so the PPS protocol stipulates that a pulsating communication between the load and the adapter should be maintained at least every 10 seconds to prevent the charging process from getting out of control.