PD is the abbreviation of Power Delivery. PD charging protocol is the power transport protocol which is published by USB-IF institute. USB-Power delivery is one of mainstream fast charging protocols, it is a fast charging standard which is made by USB-IF institute. USB PD can increase power supply by USB cable and connector, to extend the capacity of power supply which is in the application of USB. This standard can realize higher voltage and current, the power delivered can be up to 100W, and it can change the power direction at ease.
Usually, PD adapter has two outlets, USB A connector and USB C connector. From its power definition, the core function of PD power adapter is PD fast charging. After entering into the era of fast charging, the power adapter is not the same as traditional adapter, different clients would have different requirements for multi-controls, and would also have different requirement for display methods, control methods.
PD protocol is one of protocol of fast charging, it need the charging power to accord with the standard which is put forward by USB standard institute, it is very popular in the technology of fast charging. Usually, fast charging has two protocols, QC protocol and PD protocol, as the requirement of charging efficiency is different for various of manufacturers, therefore, it need use a regulation to limit them, then, the PD protocol and QC protocol have appeared.