Protocol for managing a controllable power adapter accessory

摘要

A host device can manage a controllable power adapter accessory using a communication protocol. Based on information provided by the controllable power adapter accessory as to its power capabilities and the power needs and preferences of the host device, the host device can determine a desired power profile and request power from the accessory conforming to the desired profile. The desired power profile can also depend in part on the power-carrying capability of one or more cables connected between the host device and the accessory. In some instances, the host device and controllable power adapter accessory can be connected via an intermediary accessory that can siphon power from the controllable power adapter accessory, and the host device can manage the power siphoning behavior of the intermediary accessory using the communication protocol.

主权项

1. A method of operating a host device, the method comprising, by the host device:
receiving a device-class signal from an accessory via a first set of pins of a connector of the host device, the device-class signal corresponding to a device class that includes a controllable power adapter accessory; establishing an accessory-protocol communication channel with the accessory using the first set of pins; obtaining, via the accessory-protocol communication channel, accessory identification information from the accessory, the accessory identification information including information descriptive of a controllable power-supplying capability of the accessory; receiving, via a second set of pins of the connector, cable authentication information from a cable connected between the host device and the accessory; determining a power rating of the cable based at least in part on the cable authentication information; determining a power profile for power to be supplied by the accessory to the host device via the cable, the determination of the power profile being based on the power-supplying capability of the accessory, the power rating of the cable, and a power need of the host device; and sending a power management message to the accessory via the accessory-protocol communication channel, the power management message specifying the power profile.