PD fast charging is a fast charging specification formulated by USB-IF organization, and it is one of the mainstream fast charging protocols. PD charging protocol can increase the default power of 5V/2A Type-c interface to 100W. The charging head made by PD fast charging specification has the characteristics of intelligent, safe, efficient and stable charging. Because Google announced that the fast charging protocol for mobile phones with Android7.0 or above must support the PD protocol, it is a huge market opportunity for PD fast charging products. This paper will mainly explain to you how PD fast charging products work and what kind of discrete device products are needed internally.

How do PD fast charging products work?

PD fast charging products rely on the main control chip and components to realize the intelligent adjustment of the voltage and current of the products. PD fast charging adopts a communication protocol based on USB-C port, and realizes the information exchange between the charger and the equipment through USB-C interface. USB-C interface has become the standard interface of many devices, which also shows that the application scenario of PD fast charging products is huge.

Usually, there are different schemes for PD fast charging, such as voltage and current, which may be different from manufacturer to manufacturer. Many PD fast charging chargers can provide different voltages such as 5V, 9V, 15V and 20V, and can also provide different currents such as 0.5-2A, 1-3A, 3-5A and 5-10A. By adjusting the voltage and current of the product at the same time, higher charging power can be achieved, up to 100W W.

Why is PD fast charging product good? This is because it is more intelligent, efficient and standardized. During the charging process, the electronic equipment will communicate with the charger to inform it of the required voltage and current. This is because the CC on the USB-C interface is equipped with channel pins. After receiving the request sent by the equipment, the charger will intelligently adjust the output voltage and current according to the requirements of the equipment. This intelligent adjustment can reduce the energy consumption and heat generation during charging. PD fast charging products can be applied to smart phones, tablet computers, notebook computers, smart wearable devices, smart home appliances, in-vehicle entertainment and display, game consoles and other electronic products.

PD fast charging products usually include many safety protection mechanisms, such as over-current protection, over-voltage protection, short-circuit protection, etc. These mechanisms ensure the fast, safe and efficient charging of products, and require more safety, stability, high performance and reliability for products of discrete devices. The above picture shows that discrete devices are used to realize the functions of fast charging, rectification, voltage stabilization and switching of PD.

Take the commonly used 65W fast charging product scheme as an example, which includes rectifier circuit, which may adopt rectifier bridge, primary high-frequency conversion circuit, fast recovery rectifier diode, rectifier diode, Schottky diode, switching MOS tube and other products, and secondary synchronous rectifier circuit adopts rectifier MOS tube. Hottech can provide RS1M diode products, GBUJ406 bridge stack and BAV21WS Schottky diodes for fast charging products.