Patent ID: 8222875

Claim:
An apparatus comprising: a system control unit which is capable of providing a code for designating an operation voltage thereof; a control circuit which is coupled to receive the code provided from the system control unit and which provides a first control signal and a second control signal according to the code provided from the system control unit; a first switching regulator which is coupled to receive an input voltage and the first control signal and which provides a first voltage lower than the input voltage, the first voltage being set according to the first control signal; and a second switching regulator which is coupled to receive the first voltage from the first switching regulator and the second control signal and which provides a second voltage which is lower than the first voltage and which is supplied to the system control unit as the operation voltage thereof, the second voltage being set according to the second control signal, wherein the second switching regulator includes an N-phase switching regulator that has N output circuits, and wherein the input voltage is set to be higher than the first voltage and the first voltage is higher than the second voltage.