Patent attributes
An apparatus and method allows selection of either one of main power supplied from a battery and DC Output (DCO) power supplied from a DC/DC converter included in a power management integrated circuit (PMIC) as the input power of an LDO regulator and supply of the selected power to the LDO regulator. The voltage of the input power of the LDO regulator is as low as possible, thus to reduce power loss caused by the LDO regulator. Also, DCO power supplied from the DC/DC converter included in the PMIC is supplied to the LDO regulator as the input power, and if a load connected to the DC/DC converter is turned off, the DC/DC converter is variably controlled to reduce the voltage of the input power supplied to the LDO regulator to be as low as possible, to thus reduce power loss caused by the LDO regulator.