| 摘要 |
A method involves detecting an inrush current that flows out of a USB port of a first electronic device when a central processing unit (CPU) of the first electronic device is not being powered. The inrush current is detected by a novel inrush current detect circuit when a second electronic device is connected to the USB port. In one example, the first electronic device is a laptop computer having a battery and a USB DC-to-DC converter. The inrush current detect circuit enables the USB DC-to-DC converter such that the USB DC-to-DC converter receives power from the battery and supplies a regulated voltage to the second electronic device through the USB port while the CPU remains unpowered (not drawing power from the battery).
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