What is fast charging? What are PD 3.0 and QC 3.0?

What is fast charging? What do USB PD 3.0 and QC 3.0 (or QC 4.0) mean? How to choose a power adapter? This article briefly introduces you.

In the case of cell phone battery technology stagnation, if you want to increase the use time, two commonly used methods are: increasing the battery capacity and increasing the charging speed. Since increasing the battery capacity will cause the phone to become thick and heavy, increasing the charging speed is a good solution.

What is fast charging?

We have all seen this simple formula: P (power) = V (voltage) * I (voltage). Yes, the principle of fast charging of mobile phones is to increase the input power. There are three ways to increase power: 1. increase current; 2. increase voltage; 3. dynamically increase voltage and current. Currently, mainstream fast charging protocols mainly include two: Quick Charge (QC) and USB Power Delivery (USB PD).

Quick Charge

Quick Charge (QC) is a fast charging technology developed by Qualcomm Technologies, which has been developed to the fourth generation (QC 4.0).

QC 3.0 features

• The interface supports USB-A and USB-C;
• Class A version supports 3.6V~12V dynamic voltage;
• Class B version supports 3.6V~20V dynamic voltage;
• Dynamic current, maximum support 3A;
• The maximum power is 18W.

QC 4.0 /QC 4.0+ features

• The interface supports USB-C, compatible with USB PD;
• 3.6V~12V dynamic voltage;
• Dynamic current, maximum support 4.6A;
• The maximum power is 28W.

USB Power Delivery (USB PD)

USB PD is a power supply standard based on USB C, and the maximum power supply can reach 100W. With the popularization of the USB C interface, more and more devices use USB PD fast charging solutions, such as mobile phones, laptops, and monitors.

USB PD 3.0 features

• The interface supports USB-C, compatible with PD 2.0;
• 3.0V~21V dynamic voltage;
• Current: 1.5A, 2A, 3A, 5A;
• The maximum power is 100W.

Other fast charge

In addition to QC 3.0 /QC 4.0 and USB PD 3.0, there are other fast charging protocols, such as Huawei FCP/SCP, Samsung AFC, MTK PE, etc.