US Patent 9240700 Cascading power for accessories

Methods, systems, and apparatuses for charging a host device from a charging source through an accessory are described. Upon detecting an input power signal from the charging source, an accessory may send an identification request to the host device and authenticate the host device based on the identification information received from the host device. Upon authenticating the host device, the accessory may enable a power path between the charging source and the host device to supply a charging current to charge the host device.