Patent ID: 8364989

Claim:
A power supply input selection circuit for selecting one of a plurality of external power supply inputs to supply power to a driven circuit, comprising: a power supply input switching circuit configured to provide operating power to the driven circuit by routing a selected one of the external power supply inputs to the driven circuit as a function of external power supply selection information; a latch configured to be powered directly via any of the plurality of external power supply inputs and to store the external power supply selection information; and a logic circuit configured to change the external power supply selection information stored in the latch if a default power mode does not match a desired power mode, the logic circuit being further configured to reset the power supply input selection circuit after changing the external power supply selection information stored in the latch, the external power supply selection information stored in the latch being maintained during the reset, wherein the power supply input switching circuit provides a desired one of the external power supply inputs after the logic circuit resets the power supply input selection circuit.