Charging a Provider/Consumer with a Dead Battery via USB Power Delivery

摘要

A VBUS conductor is checked to determine whether a voltage on the VBUS conductor is greater than a vSafe0V voltage within a detect time interval. A device policy manager applies a vSafeDB voltage to the VBUS conductor when the voltage on the VBUS conductor is greater than the vSafe0V voltage. The policy engine waits for a bit stream to be detected within a timer interval. When the bit stream is not detected within the timer interval, the device policy manager is instructed to apply the vSafe0V voltage to the VBUS conductor. The device policy manager applies a vSafe5V voltage to the VBUS conductor when the bit stream is detected, and the policy engine waits for the bit stream to stop within a device ready timer interval. When the bit stream has stopped within the device ready timer interval, the policy engine sends capabilities as a source port.

主权项

1. An apparatus that is configured to operate as a consumer/provider, the apparatus comprising:
an interface having a power bus and a data bus, wherein the interface is configured to be coupled to a cable, and wherein the power bus includes a VBUS conductor and a ground conductor; an isolation circuit that is coupled to the VBUS conductor; a power system that is configured to be coupled to a power source and that is coupled to the inductor; a power transceiver that is coupled to the power system and the VBUS conductor, wherein the power transceiver has a device policy manager and a policy engine, wherein the policy engine is configured to interact with the device policy manager, wherein the power transceiver is configured to:
check the VBUS conductor to determine whether the voltage on the VBUS conductor is greater than a vSafe0V voltage within a dead battery detect time interval;instruct the device policy manager to apply a vSafeDB voltage to the VBUS conductor if the voltage on the VBUS conductor is not greater than the vSafe0V voltage;wait for a bit stream to be detected within a bit stream detect time interval;instruct the device policy manager to apply the vSafe0V voltage to the VBUS conductor if the bit stream is not detected within the bit stream detect timer interval; andinstruct the device policy manager to apply a vSafe5V voltage to the VBUS conductor if the bit stream is detected; andsend capabilities as a source port after the bit stream has stopped; and a capacitor that is coupled between the power transceiver and the VBUS conductor.