Near-threshold startup integrated boost converter with slew rate enhanced error amplifier

Abstract

An integrated voltage-mode boost converter that starts up at 0.9 V is successfully implemented in a standard 3.3/5 V 0.6 mum CMOS process with V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">tn</sub> =0.7 V and |V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">tp</sub> |=0.8 V. The special features are: (1) a near-threshold soft-start circuit that keeps maximum in-rush current under control; (2) a slew rate enhanced error amplifier that achieves stable response over a wide range of supply voltage; and (3) a capacitor multiplier in implementing the compensation capacitor that reduces die area. Maximum efficiency of 93% is achieved at an output power of 260 mW.