ADAPTIVE USB CHARGING METHOD AND SYSTEM

摘要

An adaptive universal serial bus (USB) charging method and system are disclosed. In a low-power state, a USB device is charged with a non-USB charging mode. The non-USB charging mode is retained when no variation of a data signal coupled to the USB device is detected. When the data signal possesses variation for a first period, it is switched to a third proprietary charging mode.

主权项

1. An adaptive Universal Serial Bus (USB) charging method, comprising:
charging a USB device according to a non-USB charging mode in a low-power state; providing a first reference signal and a second reference signal to a positive data input pin and a negative data input pin of a differential data input pair of the USB device, respectively; retaining the non-USB charging mode when the voltage levels responding by the USB device on the positive data input pin and the negative data input pin are the same with the first reference signal and the second reference signal, respectively; and switching to a third proprietary charging mode when the voltage levels responding by the USB device on the positive data input pin and the negative data input pin are different from the first reference signal and the second reference signal for a first period, respectively.