Patent ID: 7447922

Claim:
A system for providing power comprising: a host configured to identify compatible peripheral devices that can be used in supplying power to said host over a Universal Serial Bus (USB) connection between said host and a compatible peripheral device, said USB connection including a voltage line and a ground line, a power supply in said host to apply a first voltage to said voltage line, a power supply in the said peripheral device to apply a second voltage greater than said first voltage to said voltage line in response to commands received from said host to cause said power supply in said peripheral device to apply said second voltage to said voltage line without having to first determine whether said host is capable of receiving power over said USB connection, a battery in said host, a battery charging circuit in said host adapted to charge said battery when a potential is applied to said battery charging circuit, and a circuit in said host to connect said voltage line to said battery charging circuit when the potential on said voltage line is greater than said first voltage, wherein said battery in said host can be charged by said power supply in said peripheral device via said USB connection.