A 12-to-1 V Quad-Output Switched-Capacitor Buck Converter With Shared DC Capacitors
Tingxu Hu, Mo Huang, Rui P. Martins, Yan Lü
Abstract
This article presents a 12-to-1 V quad-output switched-capacitor buck (SCB) converter with shared dc capacitors ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{\mathrm {DC}}\text{s}$ </tex-math></inline-formula> ). 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{\mathrm {DC}}\text{s}$ </tex-math></inline-formula> . Second, based on the single-output SCB, we proposed multiple-output SCB converter that shares the two <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{\mathrm {DC}}\text{s}$ </tex-math></inline-formula> among the channels. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{\mathrm {DC}}$ </tex-math></inline-formula> -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/mm3 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.