Improved on-chip components for integrated DC-DC converters in 0.13 µm CMOS

A fully-integrated DC-DC converter with on-chip inductors and capacitors is realized in a 0.13 µm CMOS technology. By using an asymmetric, high-Q inductor, power efficiency comparable to that of converters implemented with off-chip inductors is achieved. Straightforward analysis of high-density capacitor structure results in minimal ESR and optimal filtering of the output. The manufactured converter achieves a peak power efficiency of 80.5 % for an optimal load current of 170 mA and a voltage conversion ratio of 0.76 when switching at 180 MHz. This design is approximately 23 % more efficient than a linear regulator at a voltage conversion ratio of 0.55. A simple voltage mode PWM control keeps the output stable at the desired level, under load conditions from 0 mW to 720 mW.