A High-Efficiency CMOS DC-DC Converter With 9-$\ \mu$s Transient Recovery Time

This paper presents an efficient CMOS dc-dc converter with fast transient recovery. A fast-transient control operating in conjunction with a linearly scaled gate-driving technique is used to concurrently improve the transient response and light-load efficiency of a dc-dc converter. The controller operates under a pulse-width modulation mode during steady state and enables a saturation mode during transient to attain fast transient response. The linearly scaled gate-driving technique optimizes the gate-driving voltage with respect to the changing load leading to lower gate-driving loss and better light-load efficiency. A prototype chip was implemented using a commercial 0.35-μm CMOS process to validate the proposed techniques. The measurement result shows a 5% increase in light-load efficiency and achieves an overall maximum efficiency of 90%. Moreover, the transient recovery time of a 450 mA step load change is less than 9 μs.