Digitally controlled integrated DC-DC converters with fast transient response

Fast load transient response and high power conversion efficiency in DC-DC converters have conflicting requirements on the size of the inductor. In this paper, an integrated point-of-load (POL) DC-DC converter with an smaller auxiliary output stage added in parallel to the main output switching stage to help reduce the output voltage deviation during load transient is investigated. The transistor sizing of the auxiliary output stage in relation to the main output stage is studied through analysis and simulation of a 12 V to 1 V, 3 W, buck converter. The auxiliary output stage performs well with transistors occupying as little as 5% the area of the main output stage.