USB - Battery Charing

Getting to the bottom of USB Battery Charging (了解 USB 电池充电的真相)

如今，几乎所有带电池的产品都被期望支持 BC1.2 USB 充电标准。

Today, almost every product with a battery is expected to support the BC1.2 standard for USB charging.

这对消费者来说是个好消息。USB Type-C® Power Delivery 目前支持高达 240W 的充电功率，并且向下兼容。BC1.2 定义的充电端口可使便携式设备吸收更多电流，这意味着充电速度更快。BC1.2 还为未来的快速充电技术奠定了基础。不过，这也意味着使用 USB Type-C 插座并支持 Power Delivery 的流行 USB-C 充电器和笔记本电脑的制造商必须确保其产品支持 BC1.2，并通过 BC1.2 认证测试。

That’s good news for consumers. USB Type-C® Power Delivery currently supports charging at up to 240W and is also downward compatible. The BC1.2-defined charging port enables portable devices to absorb more current, which means quicker charging. BC1.2 also lays the foundation for future quick charge technologies. However, it also means that manufacturers of popular USB-C chargers and laptops that use a USB Type-C receptacle and support Power Delivery, must ensure their products support BC1.2 and pass the BC1.2 test for certification.

本文旨在介绍 BC1.2 认证的基本操作原理和测试项目，帮助制造商减少设计中遇到的问题，顺利通过测试。

This article is aimed at providing an understanding of the basic operational principles and test items for BC1.2 certification, to help manufacturers reduce the problems encountered in design, and pass tests smoothly.

1，Introduction to BC 1.2 (BC 1.2 介绍)

基于 USB 2.0 的 Vbus 电源可提供 500mA 的最大供电电流。但是，移动电话等便携设备的充电时间较长。

A Vbus power supply based on USB 2.0 can provide a maximum supply current of 500mA. However, a portable device such as a mobile phone can take a long time to recharge.

2010 年 10 月发布的 USB-IF 电池充电 1.2 规范要求便携式设备在连接 USB 主机或集线器充电时吸收最大电流 1500mA（相当于 USB 2.0 的三倍）。这样，设备就能在原来三分之一的时间内完成充电。

The USB-IF’s Battery Charging 1.2 specification, which was issued in October 2010, requires portable devices to absorb a maximum current of 1500mA (equivalent to three times that of USB 2.0) during charging when connecting to a USB host or a hub. This enables the device to be recharged in a third of the original time.

便携式设备和 USB 主机或集线器都需要支持 BC1.2，通过检测 USB D+ 和 D- 触点来确认是否支持BC 1.2。一旦检测完成并确认支持 BC1.2，Vbus 就会提供 1500mA 的充电电流。

The portable device and USB host or hub both need to support BC1.2, which detects the USB D+ and D- contacts. Once this is complete and support for BC1.2 is confirmed, Vbus provides 1500mA current for recharging.

2，Charging capacity comparison (充电能力比较)

支持 BC1.2 的手机的充电能力会有所不同，这取决于手机是通过标准 USB3 端口（SDP）连接到笔记本电脑，还是通过支持 BC1.2 的 USB3（CDP）连接到笔记本电脑？

The charging capacity of mobile phones supporting BC1.2 varies, depending on whether they connect to laptops via standard USB3 ports (SDP) or laptops with USB3 supporting BC1.2 (CDP)?

当手机连接到带有标准 USB3 端口（不支持 BC1.2）的笔记本电脑时，最大可吸收电流为 900mA。

When the mobile phone connects to a laptop with standard USB3 ports (not supporting BC1.2), the maximum absorbable current is 900mA.

• 当手机已连接、未配置且未进入暂停状态时，最大可吸收电流为 100 mA。

• 当手机已连接、已配置且未进入暂停状态时，最大可吸收电流为 900 mA（USB 3.2 为 900 mA，USB 2.0 为 500mA）。

• 当手机已连接、已配置并进入暂停状态时，最大可吸收电流为 2.5 mA。

• When the mobile phone is connected, unconfigured, and has not entered the Suspend state, the maximum absorbable current is 100 mA.

• When the mobile phone is connected, configured, and has not entered the Suspend state, the maximum absorbable current is 900 mA (900 mA for USB 3.2, 500mA for USB 2.0).

• When the mobile phone is connected, configured, and has entered the Suspend state, the maximum absorbable current is 2.5 mA.

根据规范，在未配置的情况下，如果便携式设备的电池处于 "死电 "或 "弱电 "状态，最大可吸收电流应为 100 mA。(弱电池状态意味着可以用最小的能量启动设备，而死机状态则意味着无法启动设备）。

According to the specification, without being configured, if the battery of a portable device is in the Dead or Weak state, the maximum absorbable current should be 100 mA. (a Weak battery state means the device can be started with the minimum of energy, while the Dead state means the device cannot be started)

SDP（标准下游端口）是指不支持 BC1.2 的标准端口。

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