A step-up circuit is equipped with a step-up clock signal generation device that
generates a clock signal to be used for stepping up voltage, a plurality of step-up
stages for successively stepping up a power supply voltage based on the clock signal,
and control devices that controls, after starting an operation, the stepped up
clock signal generated by the step-up clock signal generation device to be supplied
to the plurality of step-up stages at different timings.
