In-depth analysis of USB PD fast charging protocol and its industry applications

1. Overview of USB PD protocol

The USB Power Delivery (USB PD) protocol was launched by USB-IF. It is a universal fast charging standard that supports high-power charging through

 the USB-C interface. Compared with the traditional USB protocol, the PD protocol supports power output up to 240W and allows the voltage and current

 between the device and the charger to be adjusted according to actual needs. Its latest PD 3.1 version provides a higher voltage level (up to 48V), 

meeting the charging needs of a wider range of devices, including laptops, smartphones, etc.

2. Technical characteristics and advantages of the PD protocol

The PD protocol uses the CC (Configuration Channel) pin for communication, which is different from the D+/D- pins used by other fast charging protocols

 (such as the QC protocol). The flexibility of the protocol enables it to achieve dynamic adjustment from 5V to 20V (even 28V or higher voltage), allowing 

devices to accurately distribute power according to actual power needs. For example, mobile phones usually require 9V or lower voltage, while laptops 

require higher voltages (such as 20V or 28V) to meet high power requirements.

3. Introduction of PPS fast charging

The programmable power supply (PPS) mode is introduced in PD 3.0 and above. This feature allows the device to achieve more detailed voltage 

regulation during charging (such as continuous voltage regulation from 3V to 20V) to reduce battery overheating and energy loss and improve charging

 efficiency. This function is particularly common in smartphone charging, and can flexibly adjust the output voltage and current according to the battery 

status.

4. Adapter device and charging cable requirements

Devices and chargers that support the USB PD protocol are becoming more and more popular. Chargers usually use USB-C interfaces to ensure 

compatibility and efficient charging. The C to C or C to Lightning charging cable has an embedded E-marker chip to record and transmit the maximum 

current information, thereby achieving current transmission of up to 5A. For current transmission exceeding 5A, the manufacturer's private protocol is

 usually required.

5. Extended application of USB PD 3.1

The introduction of the PD 3.1 protocol increases the maximum power to 240W, expanding its application areas. In addition to common mobile phones 

and tablets, the PD protocol can now also support fast charging of gaming devices, laptops, and even some small home appliances. For example, some

 high-power laptops (such as Huawei, Lenovo, and Samsung) have adopted the PD protocol for fast charging while still maintaining the safety of the 

device.

6. Industry Trends and Future Outlook

As the USB PD protocol gradually becomes the global fast charging standard, its application scope is expanding. Many electronic product manufacturers

 are accelerating the launch of devices that support PD 3.1, covering smartphones, laptops, smart home devices, etc. With the development of technology, 

the PD protocol is expected to become the mainstream solution for more high-power application scenarios.

As a universal fast charging protocol, the USB PD protocol has the characteristics of high power support, flexible voltage regulation, and wide device 

compatibility. Its latest PD 3.1 version has greatly increased the charging power and met the diverse needs from smartphones to high-power laptops. 

In the future, with the further development of fast charging technology, the USB PD protocol will continue to promote the efficient and safe charging 

of electronic devices and become the core technology of the industry standard.