An Independently Programmable Multioutput SAR SC DC-DC Converter

This article presents an integrated independently programmable multioutput (MO) successive approximation (SAR) switched-capacitor (SC) DC-DC converter with two independently programmable output channels ranging outputs between 0.4 V and$V_{\text {BAT}}$with resolution of$V_{\text {BAT}}/{3^{N}}$where$V_{\text {BAT}}$is the input voltage and N is the number of SC units cascaded in SAR structure. A modified dual-output (DO) SC DC-DC converter unit cell is proposed with reduced ripple at its output and is integrated in the SAR-SC structure to deliver a wide input and output voltage range. The modified DO-SC units are cascaded via switch boxes to yield a fine-grain voltage resolution. The 1357 ordered pairs of conversion ratios (CRs) ensure that the two output channels are orthogonal and have near-zero crosstalk under varying load conditions. The proposed converter is fabricated in 180 nm CMOS process and achieves a peak efficiency of 94% across a combined load variation of 10 to$800{\,}\mu $A.