Design of buck converter circuits operating in weak-inversion region

A 900-nA quiescent current Buck converter is implemented in standard 0.25 μm CMOS technology. The controller's analog subblocks are designed to operate in weak-inversion region to reduce quiescent current. It also implements internal compensation circuit to minimize external passive components. In order to reduce the size of an on-chip capacitor, the Miller effect is utilized. The measurement results show the successful operation of the DC-DC converter in extremely low quiescent current.