Fast charge agreement

Now, the consumer electronics have entered the era of fast charging, how does the power adapter communicate with the mobile phone during the fast charging process? Today, I will take you to understand the fast charge from the protocol level and appreciate the mystery of the fast charge protocol!

Fast charge refers to fast charging of mobile phones and other devices. Through software and hardware technical means, the input values ​​of the voltage and current of the mobile phone are adjusted to shorten the charging time of the mobile phone and break the traditional 5V1A and 5V2A models. Ways to increase the charging speed: constant current, increase voltage; constant voltage, increase current; increase both voltage and current. With the increase in market demand, these three models have emerged and improved on the market, but different manufacturers choose different solutions and derive multiple fast charging protocols.

The current mainstream fast charging modes include PD fast charging, Qualcomm QC3.0, MediaTek’s PE protocol, OPPO, Vivo’s flash charging, Huawei’s SCP and so on. In order to standardize fast charging standards, USB-IF (USB Standardization Organization) has released an important update of USB PD 3.0, which aims to unify the fast charging technical specification program and does not allow the USB interface to perform voltage adjustments through non-USB PD protocols. Google also announced The fast charging protocol on mobile phones above Android7.0 must support the PD protocol, which speeds up the integration of the PD protocol. Let's take USB-PD as an example to fully understand the fast charging of mobile phones.

USB-PD charging principle
USB Power delivery (USB PD) is one of the current mainstream fast charging protocols formulated by the USB-IF organization. It can increase the power of the Type C interface with the default maximum power of 5V2A to 100W, and can transmit power in both directions and even networking. . With system-level power supply scheme.
USB PD communication modulates 24MHz by the AC-coupled FSK signal on the VBUS for half-duplex communication, so as to realize the charging process of the mobile phone and the charger.

The Source and Sink respectively represent the adapter and the internal chip SINK controller of the mobile phone. From the perspective of USB communication, it can be understood as USBHOST (master device) and USBOTG (as slave device). When the cable is connected, the SOP communication of the PD protocol is It will start on the CC line (Type-c interface communication configuration channel) to select the specification of point transmission. In this part, the SINK end asks the SOURE end for the power configuration parameters that can be provided, such as 5V, 9V, 15V, 20V

The mobile phone can dynamically send messages to request the charger to change the output voltage and current during the charging process, so as to realize the fast charging process.