Patent ID: 7541788

Claim:
A switching regulator converting an input voltage to a predetermined voltage and outputting the predetermined voltage to a load through an output terminal, comprising: a first switching element including a first control electrode, said first switching element performing switching according to a control signal input to the first control electrode and controlling outputting the input voltage; a second switching element including a second control electrode having capacitance smaller than the capacitance of the first control electrode of the first switching element and an on-resistance larger than the on-resistance of the first switching element, said second switching element performing switching according to a control signal input to the second control electrode and controlling outputting the input voltage; a control switching circuit part performing one of a PWM control on both of the first switching element and the second switching element and a PFM control only on the second switching element according to an operating mode so that a voltage output from the output terminal is the predetermined voltage; and a smoothing circuit smoothing a voltage output from each of the first switching element and the second switching element and outputting the smoothed voltage to the output terminal, wherein said control switching circuit part performs said PWM control to increase the voltage from said output terminal step by step from a predetermined first voltage to a second voltage when a first operating mode shifts into a second operating mode, and wherein in said first operating mode, said PFM control is performed and the output voltage from said output terminal is the predetermined first voltage, and in said second operating mode, said PWM control is performed and the output voltage from said output terminal is the second voltage that is larger than the predetermined first voltage.