The disclosed embodiments provide a system that enables a portable computing device to receive power through multiple bus interfaces at the same time. When the system senses that a first power source is plugged into a first bus interface in the portable computing device, the system determines whether the first power source is a host or a power adapter. Next, based upon whether the first power source is a host or a power adapter, the system uses a first power manager coupled to the first bus interface to limit a first input current received from the first power source to power the computing device. The system also provides the maximum charging current to a rechargeable battery for the portable computing device by chaining together a second bus interface whether power is present on the second bus interface or not.