<p>It is possible to automatically switch the mode between a light load mode and a heavy load mode depending on the output current. There are provided a first error amplification circuit for controlling a first output circuit capable of supplying a first current level required during the heavy load mode and a second error amplification circuit for controlling a second output circuit capable of supplying a second current level (which is smaller than the first current level) during the light load mode. The first and the second error amplification circuit are controlled to be in the opposite operation states or stop state according to the mode control signal formed in accordance with the output current level. Thus, it is possible to reduce the current consumption during the light load mode and improve the transient response.</p>
