This paper presents a multi-stage asynchronous hybrid buck-boost DC-DC converter with a 5V-48V input and 5V-48V output range. The converter adopts a three-stage architecture, where the input and output stages each utilize a ladder switched-capacitor converter (SCC) to reduce switch voltage stress and inductor voltage swing. An intermediate reconfigurable buck-boost stage ensures output voltage regulation and extends the effective duty cycle. Crucially, the converter eliminates the requirement for synchronizing capacitor charge/discharge and inductor energizing/de-energizing across the entire conversion ratio range, always allowing for fixed 50% duty cycle PWM control of the SCC, thereby avoiding the high capacitive current surges typically associated with extreme duty cycle. Experimental results demonstrate a peak efficiency of 93.8%. Furthermore, the asynchronous operating mode achieves an efficiency improvement of up to 26.8% compared to synchronous mode at 48V to 5V.
.jpg "Yaoming Wang (he/him/his) photo")
.jpg "Yichao Ji photo")