Circuit for supplementing electrical current to a peripheral device

摘要

A data bus can supply power from a first power source to a sink device. The data bus is coupled to a second power source. An electrical current from the second power source supplements an electrical current on the data bus if the voltage on the data bus decreases to less than a threshold value.

主权项

1. An apparatus comprising:
a data bus comprising a data conductor adapted to supply data signals to a sink device and a power conductor adapted to supply power from a first power source to the sink device; a second power source connected in parallel to the power conductor between an upstream connection node and a downstream connection node along the power connector, an electrical current from the second power source combined at the downstream node with an electrical current on the power conductor from the first power source in response to a voltage on the power conductor decreasing below a threshold value; and a recharging circuit which receives a signal provided to a light emitting diode (LED) of the sink device, the received signal having a first logic level during an inactive mode of the sink device and a second logic level during an active mode of the sink device, the recharging circuit recharging the second power source responsive to the received signal having the first logic level and interrupts recharging of the second power source responsive to the received signal transitioning to the second logic level.