A single-inductor multiple-bipolar-output (SIMBO) converter with fully-adaptive feedback matrix and improved light-load ripple

Specified for one output channel 1V to 4V, the second one 1.8V to 4V and the last one 0V to -1.8V, a prototype of single-inductor multiple-bipolar-output (SIMBO) DC-DC converter performed on 0.25-μm CMOS mixed signal process is presented. Fully-adaptive feedback matrix in pulse-width modulation (PWM) control to suppress cross regulation and constant-voltage-ripple pulse-frequency modulation (PFM) control to achieve fair light-load ripple for various conversion mode and wide-range conversion ratio are proposed. This converter can automatically switch between PWM and PFM control. The peak conversion efficiency is close to 90%.