An 800mW fully-integrated 130nm CMOS DC-DC step-down multi-phase converter, with on-chip spiral inductors and capacitors

A fully-integrated DC-DC step-down four-phase converter in a 130 nm 1.2 V CMOS technology is realized. Integrated metal-track inductors and integrated MOS and MIM capacitors are used for the output filter. No external components are required. The converter is designed to generate an output voltage of 1.2 V out of a 2.6 V supply voltage. Stacked transistors are used to cope with the high voltage. The maximum power conversion efficiency is 58 %, for a voltage conversion ratio of 0.46. This yields a 21 % efficiency enhancement factor over a linear regulator. The maximum output power of 800 mW is the highest ever reported for a fully-integrated DC-DC converter, by the authors knowledge. A novel control system, based on a semi-constant on/off-time keeps the output voltage constant at varying load and line conditions. Moreover it ensures stability over the entire load range from 0 mW to 800 mW.