An Integrated DC–DC Boost Converter Having Low-Output Ripple Suitable for Analog Applications

This paper presents an integrated boost converter having very low output voltage ripple making it suitable for analog applications, which are sensitive to supply noise. Architecturally, the converter consists of a conventional boost converter followed by an <italic>L–C</italic> filter, which drastically reduces the output ripple. The <italic>L–C</italic> filter has been realized using 30-nH bondwire inductance and 0.54-nF on-chip capacitance. The converter switches at 118 MHz and produces a regulated 3.2-V output from an input voltage ranging from 1.0 to 2.7 V. The converter is able to deliver up to 65-mA current for input voltage <inline-formula><tex-math notation="LaTeX"> $\geq$</tex-math></inline-formula> 2.4 V. The prototype has been implemented in 0.18-<inline-formula> <tex-math notation="LaTeX">$\mu$</tex-math></inline-formula>m standard digital CMOS process and the entire design consumes only 0.52-mm<inline-formula><tex-math notation="LaTeX">$^2$</tex-math></inline-formula> chip area resulting in a maximum power density of 0.387 W/mm<inline-formula><tex-math notation="LaTeX">$^2$</tex-math></inline-formula>. Peak efficiency of the converter is 77.4% at 32.2-mA current for 2.7-V input supply. The measured maximum output ripple noise is 21 mV that is less than 0.65% of the regulated output voltage.