The voltage deviation is converted into the time quantity with the first integration circuit for the voltage detection and the second integration circuit for the voltage detection. The current setting value and the current measurements are converted into the time quantity with the second integration circuit for the current control to which the first integration circuit for the current control from which the voltage value of the set current value corresponding is input and the voltage value of the value of the current of the inductor corresponding are input and it controls. And, the start of the first integration circuit for the current control is delayed with operation quantity signal generation circuit only at the time that the high-resolution evaluation or more than the start of the first integration circuit for the current control and corresponds to the voltage deviation.