A 12-to-1 V Quad-Output Switched-Capacitor Buck Converter With Shared DC Capacitors

Abstract

This article presents a 12-to-1 V quad-output switched-capacitor buck (SCB) converter with shared dc capac- itors ( CDCs). First, we proposed single-output SCB achieving a high efficiency, with small switch area and small inductor volume under several-ampere conditions. Each single-output SCB has two CDCs. Second, based on the single-output SCB, we proposed multiple-output SCB converter that shares the two CDCs among the channels. The CDC-sharing improves the power density and efficiency under unequal-load conditions. Third, we eliminate cross-regulation in a conventional energy-store-device-sharing topology through current mode (CM) control. Besides, we use a capacitor-sourced gate drive scheme that is highly compatible with the SCB, removing the bootstrap and gate drive supply voltage generation circuits. Fabricated in a 180-nm BCD process, this design achieves a measured peak efficiency of 90.4%, and 48 mA/mm 3 power density with 85% efficiency. To our best knowledge, this is one of the first 12-to-1 V integrated hybrid converter with multiple outputs reported.