Patent ID: 7574617

Claim:
A power supply apparatus to supply power to a portable electronic device comprising a plurality of electronic components, the power supply apparatus comprising: a linear voltage regulator supplying a first power required to drive a microcomputer in an off-mode to define an off-state of the portable electronic device; a switching voltage regulator supplying a second power required to drive at least one among the plurality of electric components and the microcomputer in an on-mode to define an on-state of the portable electronic device; and a controller controlling the switching voltage regulator to supply the second power to the microcomputer in the on-mode, wherein the first power and second power have a similar voltage level, and the controller comprises a shut_down signal generator which shuts down the linear voltage regulator at or after starting the on-mode, and the controller comprises a switch controlling the power to be supplied from the switching voltage regulator to the microcomputer, and a switching controller turning on the switch when the second power is supplied in a forward bias direction from the switching voltage regulator.