As the performance of mobile phones becomes stronger and the screens become larger and larger, the power consumption of mobile phones has also increased dramatically, and fast charging has become an indispensable part. However, each brand develops their own fast charging technology and many of them are incompatible with each other which brings the consumer an abundance of inconvenience and it is a waste of resources.
In 2017, the USB-IF Association added Programmable Power Supply (PPS) to the USB PD 3.0 standard, expecting a unified specification for today's fast charging solutions. In that same year, Qualcomm’s QC4.0 complied with PPS standards, reaching a unified charging scheme. So what is Programmable Power Supply (PPS)?
The PPS standard refers to the power supply can exchange data with the power supply every ten seconds, so that the power supply can dynamically adjust the output voltage and current according to the condition of the receiving product specifications. The voltage range is between 3~ 21V, with increment of 0.02V. Due to PPS, USB-IF Association has also added "PPS Voltage Step Test" and "PPS Current Limit Test" to ensure that the current and voltage dynamic adjustment of the device during the charging process are in compliance with the Association's specifications.
Note: There are two types of fast charging modes, one is high voltage and low current, and the other is low voltage and high current. The disadvantage of the first mode is because while the withstand voltage of the mobile phone battery is 4.2V, but the input charging voltage is 9V, it is necessary to reduce voltage to 4.2V in the mobile phone. The reduction of voltage will increase the current and cause the mobile phone to easily overheat. This is the reason why you feel the increase in temperature on your mobile phone.