With the development of USB standards, not only has the data transfer speed been significantly improved, but its power supply capability has also been greatly enhanced. There are significant differences in power output, voltage level, and intelligent charging function among different versions of USB interfaces and related power supply protocols. This article will provide an in-depth analysis of several major USB categories and their power supply protocols.
一 USB 2.0
1. Default power supply: The USB 2.0 port provides 5V/500mA (2.5W) power, suitable for low-power devices such as keyboards, mice, etc.
2. BC 1.2 (Battery Charging Specification 1.2): Introduced a Dedicated Charging Port (DCP) that can provide up to 5V/1.5A (7.5W) of power. Supports multiple charging modes, including Standard Downstream Port (SDP) and Charging Downstream Port (CDP), improving the charging efficiency of portable devices.
二 USB 3.x
1. Power supply improvement: USB 3.0 and USB 3.1 default to 5V/900mA (4.5W) power supply, while USB 3.2 continues to use this standard.
2. Power Delivery (PD): Although USB 3. x itself does not change the basic power supply parameters, it is compatible with the USB PD protocol, allowing for higher power transmission.
三 USB Power Delivery (PD)
From USB PD 1.0 to the latest USB PD 3.2, each new version has added more features and higher power limits.
Features include configurable power supply, support for bidirectional power supply, which means the device can serve as both a power source and a power receiving device; And the voltage and current provided can be adjusted as needed. Multi level power: Initially, USB PD 2.0 supported multiple fixed voltage levels ranging from 5V/3A (15W) to 20V/5A (100W); USB PD 3.0 introduces Programmable Power Supply (PPS), which allows for more precise adjustment of voltage and current, optimizing the fast charging experience. Built in multiple protection mechanisms to ensure that connected devices are not damaged during use; Simultaneously maintaining good backward compatibility, even the latest PD specifications can work properly with older USB devices.
四 USB Type-C
USB Type-C is a new type of interface form with forward and reverse plug-in design, and the internal pin layout allows for more power transmission paths.
When combined with the USB PD protocol, the Type-C port can achieve a power output of up to 240W (USB PD 3.1 EPR Extended Power Range), far exceeding the capabilities of traditional USB A/B ports. Due to its powerful performance and flexibility, Type-C has become the preferred interface for modern laptops, smartphones, and other electronic products.
